Day 455

Saturday.  And Sunday.

1306.6330
The Sloan digital sky survey data release 7 spectrsoscopic m dwarf catalog iii: the spatial dependence of magnetic activity in the galaxy
Pineda, West, Bochanski, Burgasser

Analyze the magnetic activity of 59k M dwarfs from DR7.  This analysis explores the spatial distribution of M dwarf activity as a function of both vertical distance from the Galactic plane (Z) and planar distance from the Galactic center (R).  Confirm the established trends of decreasing magnetic activity (as measured by H-alpha emission) with increasing distance from the mid-plane of the disk and find evidence for a trend in Galactocentric radius.  Measure a non-zero radial gradient in the activity fraction in the analysis of stars with spectral types dM3 and dM4.  The activity fraction increases with R and can be explained by a decreasing mean stellar age with increasing distance from the Galactic center. [I guess it's the M stars that are responsible for Galactic-scale magnetic activity?  Not clearly stated in the abstract, but seems to imply so.  I guess they are abundant (low mass).]

1306.6332
The (galaxy-wide) IMF in giant elliptical galaxies: from top to bottom
Weidner, Ferraras, Vazdekis, La Barbera

Based on spectral line strengths and dynamical modeling, evidence of a non-universal stellar IMF emerges, implying an excess of low-mass stars in the most massive elliptical galaxies.  Show that a time-independent bottom-heavy IMF is compatible neither with the observed metal-rich populations found in giant ellipticals nor with the number of stellar remnants observed within these systems.  Suggest a two-stage formation scenario involving a time-dependent IMF to reconcile these observational constraints.  In this model, an early strong star-bursting stage with a top-heavy IMF is followed by a more prolonged stage with a bottom-heavy IMF.  Such model is physically motivated by the fact that a sustained high star formation will bring the interstellar medium to a state of pressure, temperature and turbulence that can drastically alter the fragmentation of the gaseous component into small clumps, promoting the formation of low-mass stars.  This toy model is in good agreement with the different observational constraints on massive elliptical galaxies, such as age, metallicity, alpha-enhancement, M/L, or the mass fraction of the stellar component in low-mass stars.

1306.6333
Chronos: a NIR spectroscopic galaxy survey.  From the formation of galaxies to the peak of activity
Ferraras, ... Conselice, et al

Chronos is a response to ESA's call for white papers to define the science for the future L2, L3 missions.  Targets the formation and evolution of galaxies, by collecting the deepest NIR spectroscopic data, from the formation of the first galaxies at z~10 to the peak of formation activity at z~1-3.  The strong emission from the atmospheric background makes this type of survey impossible from a ground-based observatory.  The spectra of galaxies represent the equivalent of DNA fingerprint [OK,], containing information about the past history of SF and chemical enrichment.  The proposed survey will allow us to dissect the formation process of galaxies including the timescales of quenching triggered by SF or AGN activity, the effect of environment, the role of infall/outflow processes, or the connection between the galaxies and their underlying dark matter haloes.  To provide these data, the mission requires a 2.5m space telescope optimized for a campaign of very deep NIR spectroscopy.  A combination of a high multiplex and very long integration times will result in the deepest, largest, high-quality spectroscopic dataset of galaxies from z=1 to 12, spanning the history of the Universe, from 400 million to 6 billion years after the big bang, i.e. covering the most active half of cosmic history.

1306.6334
The mass-metallicity relation of a z~2 protocluster with MOSFIRE
Kulas, ... Shapley, Steidel, ... et al

MOSFIRE observations of the role of environment in the formation of galaxies at z~2.  Use K-band spectroscopy of Ha and [NII] emission lines; analyze the metallicities of galaxies within and around a z=2.3 protocluster discovered in the HS1700+643 field.  Main sample consists of 23 protocluster and 20 field galaxies with estimates of stellar masses and gas-phase metallicities based on the N2 strong-line metallicity indicator.  With these data, examine the mass-metallicity relation (MZR) wth respect to environment at z~2.  Find that field galaxies follow the well-established trend between stellar mass and metallicity, such that more massive galaxies have larger metallicities.  The protocluster galaxies, however, do not exhibit a dependence of metallicity on mass, with the low-mass protocluster galaxies showing an enhancement in metallicity compared to field galaxies spanning the same mass range.  A comparison with galaxy formation models suggests that the mass-dependent environmental trend observed can be qualitatively explained in the context of the recycling of "momentum-driven" galaxy wind material.  Accordingly, winds are recycled on a shorter timescale in denser environments, leading to an enhancement in metallicity at fixed mass for all but the most massive galaxies.  Future hydrodynamical simulations of z~2 overdensities matching the one in the HS1700 field will be crucial for understanding the origin of the observed environmental trend in detail.

1306.6336
Measuring the gas clumping in Abell 133
Morandi, Cui

Developing a non-parametric method to measure inhomogeneities in the gas distribution from X-ray observations of galaxy clusters.  Apply method to Chandra X-ray observations of A133 and present the determination of gas clumping factor from X-ray cluster data.  Find that the gas clumping factor in A133 increases with radius and reaches ~2-3 at R_200.  This is in good agreement with the predictions of hydrodynamical simulations and the previous determination, but at odds with several recent Suzaku studies.  Then observe a general trend of steepening in the radial profiles of the gas density beyond 0.3 R_200, with a logarithmic slope of ~2.6 at R_200.  The observed density profiles appear to be flatter compared to simulations, but in agreement with previous observational findings.  In addition, observe that the measured temperature decreases steadily with radius toward the outskirts of A133, while the entropy increases monotonically with radius, gently flattening in the outer volumes.  With respect to theoretical predictions from pure gravitational collapse, the results presented here point to an entropy excess in the central regions, which extends out to large radii.  These results suggest that gas inhomogeneities should be treated properly when interpreting X-ray measurements in the envelope of galaxy clusters.  Finally, discuss how the brightness distribution keeps a recored of the large-scale structures formation scenario, providing a snapshot of the 'melting pot' in the virialization region.

1306.6339
A lithium depletion boundary age of 22 Myr for NGC 1960
Jeffries et al

Deep Cousins RI photometric survey of open cluster NCD 1960, complete to R_C~22, I_C~21, that is used to select a sample of very low-mass cluster candidates.  Gemini spectroscopy of a subset of these is used to confirm membership and locate the age-dependent "lithium depletion boundary" (LDB), the luminosity at which Li remains unburned in its low-mass stars.  The LDB implies a cluster age of 22pm4 Myr and is quite insensitive to choice of evolutionary model.  NGC 1960 is the youngest cluster for which a LDB age has been estimated and possesses a well populated upper main sequence and a rich low-mass pre-main sequence.  The LDB age determined here agrees well with precise age estimates made for the same cluster based on isochrone fits to its high- and low-mass populations.  The concordance between these three age estimation techniques, that rely on different facets of stellar astrophysics at very different masses, is an important step towards calibrating the absolute ages of young open clusters and lends confidence to ages determined using any one of them.  [the three are: cluster MS population evolution, LDB, and isochrone fits?  what's the difference between cluster MS population evolution and isochrone fits?----isochrone fits are fits to the color, which evolve over age, apparently.]

1306.6359
Clipping the cosmos II: cosmological information from non-linear scales
Simpson, Heavens, Heymans

A method for suppressing contributions from higher-order terms in perturbations theory, greatly increasing the amount of information which may be extracted from the matter PS.  In an evolved cosmological density field, the highest density regions are responsible for the bulk of the NL power.  By suitable down-weighting these problematic regions, find that the one- and two-loop terms are typically reduced in amplitude by ~70% and ~95% respectively, relative to the linear PS.  This greatly facilitates modeling the shape of the galaxy power spectrum, potentially increasing the number of useful Fourier modes by more than two orders of magnitude.  Provide a demonstration of how this technique allows the galaxy bias and the amplitude of linear matter perturbations sigma_8 to be determined from the PS on conventionally NL scales, 0.1<k<0.7 h/Mpc.

1306.6423
Exploring the systematic uncertainties of Type Ia supernovae as cosmological probes
Wang, Wang

No z-evolution with alpha or beta, the stretch-luminosity parameter.

1306.6466
Intrinsic alignments and 3d weak gravitational lensing
Merkel, Schaefer

Show how IA can be incorporated consistently in the formalism of 3d weak lensing.  [What is 3d WL?  3d mass reconstruction?  WL tomography?....no, apparently to "completely account for the 3-dimensional character of WL by maintaining the radial dependence of the lensing potential throughout the whole analysis (with the aid of photo-z, I presume).]  Use two different descriptions of the intrinsic galaxy ellipticities, the so-called linear and quadratic model, respectively.  For both models derive the covariance matrix of the intrinsic alignment signal (II-alginments) and GI-alignments (the cross correlation of intrinsic and lensing-induced ellipticities).  Evaluating the covariance matrices for the linear model numerically and comparing the results to the cosmic shear signal, find that for a low redshift survey the total covariance matrix is dominated by the contributions of the II-alignments.  For a Euclid-like survey II-alignments still dominated over GI-alignments, but they are more than one order of magnitude smaller than the lensing signal.  THe shape of the ellipticity covariance matrices is quite different in the k-k'-plane for cosmic shear on the one hand and IA on the other hand.  In comparison to lensing both alignment types tend to be rather elongated along the diagonal k=k'.  Moreover, for high multipoles (l~100) IA are strongly concentrated along that diagonal.

1306.6468
AGN feedback works both ways
Zinn et all

Simulations of galaxy growth need to invoke strong negative feedback from AGN to suppress the formation of stars and thus prevent the over-production of very massive systems.  While some observations provide evidence for such negative feedback, other studies find either no feedback, or even positive feedback, with increased SF associated with higher AGN luminosities.  Report an analysis of several 100 AGN and their host galaxies in the CDFS using X-ray and radio data for sample selection.  Combined with archival FIR data as a reliable tracer of SF activity in the AGN host galaxies, find that AGN with pronounced radio jets exhibit a much higher SFR than the purely X-ray selected ones, even at the same X-ray luminosities.  This difference implies that positive AGN feedback plays an important role, too, and therefore has to be accounted for in all future simulation work.  Interpret this to indicate that the enhanced SFR of radio-selected AGN arises because of jet-induced SF, as is hinted by the different jet powers among the AGN samples, while the suppressed SFR of X-ray selected AGN is caused by heating and photo-dissociation of molecular gas by the hot AGN accretion disc.

1306.6552
The nature of extremely red galaxies in the local universe
Sodré, da Silva, Santos

Investigate the nature of extremely red galaxies (ERGs), objects whose colors are redder than those found in the red sequence present in color-magnitude diagrams of galaxies.  Selected from SDSS DR7 a volume-limited sample of such galaxies in 0.010<z<0.030, brighter than M_r=-17.8 (magnitudes dereddened, corrected for the MW extinction) and with (g-r) colors larger than those of galaxies in the red sequence.  This sample contains 416 ERGs, which were classified visually.  Classification was cross-checked with other classifications available in the literature.  Found from visual classification that the majority of objects in sample are edge-on spirals (73%).  OTher spirals correspond to 13%, whereas elliptical galaxies comprise only 11% of the objects.  After comparing the morphological mix and the distributions of Ha Hb and axial ratios of ERGs and objects in the red sequence, suggest that dust, more than stellar population effects, is the driver of the red colors found in these extremely red galaxies.

1306.6565
The chemical case for no winds in dwarf irregular galaxies
Gavilán et al

Argue that isolated gas-rich dwarf galaxies (in particular dIrr) do not necessarily undergo significant gas loss.  Aim is to investigate whether the observed properties of isolated, gas-rich dwarf galaxies, not affected by external environmental processes, can be reproduced by self-consistent chemo-photometric infall models with continuous SFH and no mass or metal loss.  This model is characterized by the total mass of primordial gas available to the object, its characteristic collapse timescale, and a constant SF efficiency.  A grid of 144 such models has been computed by varying these parameters, and their predictions (elemental abundances, stellar and gas masses, photometric colors) have been compared with a set of observations of dIrr galaxies obtained from the literature.  It is found that the models with moderate to low efficiency are able to reproduce most of the observational data, including the relative abundances of nitrogen and oxygen. 

Day 454

Friday.

1306.6325
How to distinguish between cloudy mini-Neptunes and water/volatile-dominated super-earths
Benneke, Seager

One of the most profound questions about the newly discovered class of low-density super-Earths is whether these exoplanets are predominately H2-dominated mini-Neptures or volatile-rich worlds with gas envelopes dominated by H2O, CO2, CO, CH4, or N2.  Transit observations of the super-Earth GJ 1214b rule out a cloud-free H2-dominated atmosphere, but are not able to determine whether the lack of deep spectral features is due to high-altitude clouds or the presence of a high mean molecular mass atmosphere.  Here, demonstrate that one can unambiguously distinguish between cloudy mini-Neptunes and volatile-dominated worlds based on the differences in the wing steepness and relative depths of water absorption features in moderate-resolution NIR transmission spectra (R~100).  In a numerical retrieval study, show for GJ 1214b that an unambiguous distinction between a cloudy H2-dominated atmosphere and cloud-free H2 atmosphere will be possible if the uncertainties in the spectral transit depth measurements can be reduced by a factor of ~3 compared to the published HST WFC3 and VLT transit observations.  Argue that the required precision for the distinction may be achievable with currently available instrumentation by stacking 10-15 transit observations. Provide a scaling law that scales the quantitative results to other transiting super-Earths and Neptunes.  The analysis is performed using an improved version of the Bayesian atmospheric retrieval framework.  The new framework not only constrains the gas composition and cloud/haze parameters, but also determines the confidence in having detected molecules and cloud/haze species through Bayesian model comparison.  Using the Bayesian tool, demonstrate quantitatively that the subtle transit depth variation in the Berta et al (2012) data is not sufficient to claim the detection of water absorption.

Day 453

Thursday.

1306.5746
Luminosity of young Jupiters revisited.  massive cores make host planets
Mordasini

Intrinsic luminosity of young Jupiters is of high interest for planet formation theory.  Related to physical mechanisms during formation are the accretion shock structure and the basic formation mechanism (core accretion of gravitational instability).  Study the impact of the core mass on the post-formation entropy and luminosity of young giant planets forming via core accretion with a super critical shock (cold accretion).  Conduct self-consistently coupled formation and evolution calculations of giant planets with masses between 1 and 12 Jovian masses and core masses between 20 and 120 Earth masses.  Find that the post-formation luminosity of massive giant planets is very sensitive to core mass.  An increase of the core mass by a factor 6 results in an increase of post-formation luminosity of a 10 Jovian mass planet by a factor 120.   Due to this dependency, there is no single well defined post-formation luminosity for core accretion, but a wide range.  For massive cores (~100 Earth masses), the post-formation luminosities of core accretion planets become so high that they approach those in the host start scenario that is often associated with gravitational instability.  For the mechanism to work, it is necessary that the solids are accreted before or during gas runaway accretion, and that they sink deep into the planet.  Make no claims whether or not such massive cores can actually form in giant planets.  BUt if yes, it becomes difficult to rule out core accretion as formation mechanism based solely on luminosity for directly imaged planets that are more luminous than predicted for low core masses.  Instead of invoking gravitational instability as the consequently necessary formation mode, the high luminosity could also be caused simply by a more massive core.

1306.5751
Teasing bits of information out of the CMB energy spectrum
Chuluba, Jeong

CMB spectral distortions (departures from BB) encode information about the thermal history of the early Universe (1e3<z<few 1e6).  While the signal is usually characterized as mu- and y-type distortion, a smaller residual (non-y/non-mu) distortion can also be created at intermediate redshifts 1e4<z<3e5.  Here, construct a new set of observables, nu_i, that describes the principal components of this residual distortion.  The principal components are orthogonal to temperature shift, y- and mu-type distortion, and ranked by their detectability, thereby delivering a compression of all valuable information offered by the CMB spectrum.  This method provides an efficient way of analyzing the spectral distortion for given experimental settings, and can be applied to a wide range of energy-release scenarios.  As an illustration, discuss the analysis of the spectral distortion signatures caused by dissipation of small-scale acoustic waves and decaying/annihilating particles for a PIXIE-type experiments. Provide forecasts for the expected measurement uncertainties of model-parameters and detections limits in each case.  Furthermore show that a PIXIE-type experiments can in principle distinguish dissipative energy release from particle decays for a nearby scale-invariant primordial PS with small running.  Future CMB spectroscopy thus offers a unique way to probe physics in the primordial Universe.  [what's the PIXIE experiment?]

1306.5752
Galaxy and mass assembly (GAMA): witnessing the assembly of the cluster Abell 1882
Owers et al

Combined optical and X-ray analysis of the rich cluster Abell 1882 with the aim of identifying merging substructure and understanding the recent assembly history of this system.  Optical from GAMA; use 283 spectroscopically confirmed cluster members to detect and characterize substructure.  X-ray from Chandra and XMM.  A1882 harbors two main components A and B, which have a projected separation of 2 Mpc and a LoS velocity difference of -428 km/s.  The primary system A has velocity dispersion sigma_v=500km/s and Chandra (XMM) temperature kT=3.57keV (3.31keV); B has sigma_v=457km/s and kT=2.39keV (2.12keV).  The optical and X-ray estimates for the masses of the two systems are consistent within the uncertainties and indicate that there is twice as much mass in A (M_500=1.5-1.9e14 Msun) than B (0.8-1.0e14 Msun).  Interpret the A+B system as being observed prior to a core passage.  Supporting this interpretation is the large projected separation of A+B and the dearth of evidence for a recent (<2 Gyr) major interaction in the X-ray data.  Two-body analyses indicate that A and B form a bound system with bound incoming solutions strongly favored.  Compute blue fractions of f_b=0.28 and 0.18 for the spectroscopically confirmed member galaxies within r_500 of the centers of A and B, respectively.  These blue fractions do not differ significantly from the blue fraction measured from an ensemble of 20 clusters with similar redshift.

1306.5771
Panphasia: a user guide
Jenkins, Booth

Make a very large realization of a Gaussian white noise field, called PANPHASIA, public by releasing SW that computes this field.  Panphasia is designed specifically for setting up Gaussian IC for cosmo sims and re-simulations of structure formation.  Illustrate applications, including a modified version of a public serial IC generator.  Document the SW and present the results of a few basic tests of the field.  The properties and method of construction of Panphasia are described in full in a companion paper Jenkins 2013.

1306.5798
Clues on void evolution I: large scale galaxy distributions around voids
Ceccarelli, Paz, Lares, Padilla, Lambas

Statistical void environment study: examine galaxy density profiles around voids in the SDSS, finding a correlation between void-centric distance to the shell of maximum density and void radius when a maximum in overdensity exists.  Analyze voids with and without a surrounding over-dense shell in the SDSS.  Find that small voids are more frequently surrounded by over-dense shells whereas the radial galaxy density profile of large voids tends to rise smoothly towards the mean galaxy density.  Analyze the fraction of voids surrounded by overdense shells finding a continuous trend with void radius.  The differences between voids with and without an overdense shell around them can be understood in terms of whether the voids are, on average, in the process of collapsing [collapse?] or continuing their expansion, respectively, in agreement with previous theoretical expectations.  Use numerical simulations coupled to SAM of galaxy formation in order to test and interpret results.  The very good agreement between the mock catalog results and the observations provides additional support to the viability of a LCDM model to reproduce the LSS of the universe as defined by the void network, in a way which has not been analysed previously.

1306.5896
The one-dimensional Ly-alpha forest power spectrum from BOSS
Palanque-Delabrouille et al

Develop 2 independent methods to measure the one-dimensional PS of the transmitted flux in the Ly-a forest.  The first method is based on a Fourier transform, and the second on a maximum likelihood estimator.  The two methods are independent and have different systematic uncertainties.  The determination of the noise level in the data spectra was subject to a novel treatment, because of its significant impact on the derived power spectrum.  Apply the two methods to 13821 quasar spectra from DR9, selected from a larger sample of >60k spectra on the basis of their quality, S/N, and spectral resolution.  The PS measured using either approach are in good agreement over all twelve redshift bins from <z>=2.2 to 4.4, and scales from 0.001(km/s)^-1 to 0.02(km/s)^-1.  Determine the methodological and instrumental systematic uncertainties of our measurements.  Provide a preliminary cosmological interpretation of measurements using available hydrodynamical simulations.  The improvement in precision over previous results is a factor 2-3 for constraints on relevant cosmological parameters.  For a LCDM model and using a constraint on H0 that encompasses measurements based on the local distance ladder and on CMB anisotropies, infer sigma_8=0.83pm0.03 and n_s=0.97pm0.02 based on HI absorption in the range 2.1<z<3.7.

1306.5968
A new way of setting the phases for cosmological multi-scale gaussian initial conditions
Jenkins

Describe how to define an extremely large discrete realization of a Gaussian white noise field that has a hierarchical structure and the property that the value of any part of the field can be computed quickly.  Tiny subregions of such a field can be used to set the phase information for Gaussian IC for individual cosmological simulations of structure formation.  This approach has several attractive features: (i) the hierarchical structure based on an octree is particular well suited for generating follow up resimulation or zoom initial conditions; (ii) the phases are defined for all relevant physical scales in advance so that resimulation ICs are, by construction, consistent both with their parent simulation and with each other; (iii) the field can easily be made public by releasing a code to compute it - once public, phase information can be shared or published by specifying a spatial location within the realization.  In this paper describe the principles behind creating such realizations.  Define an example called PANPHASIA and in a companion paper on arXiv, make public a code to compute it.  With 50 octree levels Panphasia spans a factor of more than 1e15 in linear scale - a range that significantly exceeds the ratio of the current Hubble radius to the putative CDM free-streaming scale.  Show how to modify a code used for making cosmo and resimulation ICs so that it can take the phase information from Panphasia and, using this code, demonstrate that it is possible to make good quality resimulation ICs.  Define a convention for publishing phase information from Panphasia and publish the initial phases for several of the Virgo Consortium's most recent cosmological simulations including the 303 billion particle MXXL simulation.

1306.6096
The mass-concentration relation in massive galaxy clusters at redshift ~1
Sereno, Covone

Mass and concentration of clusters of galaxies are related and evolving with redshift.  Study the properties of a sample of 31 massive galaxy clusters at high z, 0.8<z<1.5, using WL and SL observations.  Concentration is a steep function of mass, c_200~M_200^(-0.83pm0.39), with higher-redshift clusters being less concentrated.  Mass and concentration from the stacked analysis, M_200=4.1e14 Msun/h and c_200=2.3pm0.2 are in line with theoretical results extrapolated from the local universe.  Clusters with signs of dynamical activity preferentially feature high concentrations.  Discuss the possibility that the whole sample is a mix of two different kinds of haloes.  Over-concentrated clusters might be accreting haloes out of equilibrium in a transient phase of compression, whereas less concentrated ones might be more relaxed.

1306.6117
Galaxy clusters in the line of sight to background quasars - III multi-object spectroscopy
Andrews, ... Gladders, Yee, et al

Present multi-object spectroscopy of 31 galaxy cluster candidates at 0.2<z<1.0 and centered on QSO sight-lines taken from Lopez+(2008).  The targets were selected based on the presence of an intervening MgII absorption system at a similar redshift to that of a galaxy cluster candidate lying at a projected distance < 2Mpc/h from the QSO sight-line (a 'photometric-hit').  The absorption systems span rest-frame equivalent widths between 0.015 and 2.028 A. Aim: (1) identify the absorbing galaxies and determine their impact parameters, (2) confirm the galaxy cluster candidates in the vicinity of each quasar sightline, (3) determine whether the absorbing galaxies reside in galaxy clusters.  Findings: (1) 10/24 absorbing galaxies identified, with z up to 1.0955.  (2) 20/31 cluster/group candidates spectroscopically confirmed, with most of the confirmed clusters/groups at z<0.7.  (3) 10/14 spectro confirmation of photometric hits within ~650 km/s from galaxy clusters/groups, in addition to 2 new ones related to galaxy group environments.  These number imply efficiencies of 71% in finding such systems with MOS spectroscopy.  This is remarkable, since a photometric hit was defined as those cluster-absorber pairs having a redshift difference dz=0.1.  Absorbing cluster-galaxies hosting weak absorbers are consistent with lower SF activity than the rest, which produce strong absorption and agree with typical MgII absorbing galaxies found in the literature.  Spectroscopic confirmations lend support to the selection of photometric hits made in Lopez+(2008).

1306.6148
Is GBT 1355+5439 a dark galaxy?
Oosterloo, Heald, de Blok

Present HI imaging of GBT 1355+5439 with Westerbork Synthesis Radio Telescope.  This is a dark HI object recently discovered close to the nearby galaxy M101.  Find this object to be an HI cloud 5x3 arcmin in size.  THe total HI image in and the kinematics show that the cloud consists of condensations that have small (~10 km/s) motions with respect to each other.  THe column densities of the HI are low; the observed peak value is 7.1e19 cm^-2.  The velocity field shows a mild velocity gradient over the body of this object, possibly due to rotation, but it may also indicate large-scale radial motions.  Data limited in sensitivity, but at all positions the HI velocity dispersion is higher than 5 km/s and no narrow, cold, HI component is seen.  Because its distance is not known, consider various possibilities for the nature of this object.  Both scenarios of a tidal remnant near M101 and that it is a dark dwarf companion of M101 meet difficulties.  Neither do the data fit the properties of known compact high-velocity clouds in the galactic halo exactly, but we cannot entirely exclude this option and deeper observations are required.  Also considered the possibility that this object is a gas-rich dark minihalo in the outer regions of the Local Group.  It would then have similar properties as the clouds of a proposed Local Group population recently found in the ALFALFA survey.  In this case, the HI mass of this object would be about a few times 1e5 Msun, its size about 1kpc, and the dynamical mass M_dyn > 5e7 Msun.  However, if this is a dark Local Group object, the internal kinematics of the HI appears to be different from that of gas-dominated, almost dark galaxies of similar size.

1306.6151
Source-lens clustering bias of weak-lensing estimators
Valageas

Estimate the amplitude of the source-lens clustering bias of weak lensing estimators of the 2-pt and 3-pt convergence and cosmic shear correlation functions.  Use a linear galaxy bias model for the galaxy-density correlations.  For the 3-pt and 4-pt density correlations, use analytical or semi-analytical models, based on a hierarchical ansatz or a combination of one-loop perturbation theory with a halo model.  For two-point statistics, find that the source-lens clustering bias is typically several orders of magnitude below the weak lensing signal, except when we correlate a low-redshift galaxy (z<0.05) with a higher redshift galaxy (z>0.5), where it can reach 10% of the signal for the shear.  For 3-pt statistics, the source-lens clustering bias is typically of order 10% of the signal, as soon as the 3 galaxy source redshifts are not identical.

1306.6191
Low-resolution spectrum of the Zodiacal light with AKARI InfraRed camera
Tsumura et al

Present NIR and MIR zodiacal light spectrum from AKARI IRC.  A catalog of 278 spectra of the diffuse sky covering a wide range of Galactic and ecliptic latitudes constructed.  Wavelength range: 1.8-5.3 um with resolution of lambda/Delta lambda ~ 20.  Analysis of the spectra collected in different seasons and ecliptic latitudes, confirm that the spectral shape of the scattered component and the thermal emission component of zodiacal light does not show any dependence on location and time, but relative brightness between them varies with location.  Also confirmed that the color temperature of the zodiacal emission at 3-5 um is 300 pm 10 K at any ecliptic latitude.  This emission is expected to be originated from sub-micron dust particles in interplanetary space.

Day 452

Wednesday.

1306.5745
The imprint of inhomogeneous HeII reionization on the HI and HeII Ly-alpha forest
Compostella, Cantalupo, Porciani

Use a set of AMR hydrodynamic sims post-processed with the radiative-transfer code RADAMESH to study how inhomogeneous HeII reionization affects the IGM.  Propagate radiation from AGNs considering two scenarios for the time evolution of the ionizing sources.  Find that HeII reionization takes place in a very inhomogeneous fashion, through the production of well separated bubbles of the ionized phase that subsequently percolate.  Overall, the reionization process is extended in time and lasts for a redshift interval Delta z>1.  At fixed gas density, the temperature distribution is bimodal during the early phases of HeII reionization and cannot be described by a simple effective equation of state.  When HeII reioinzation is complete, the IGM is characterized by polytropic equation of state with index gamma~1.20.  This relation is appreciably flatter than at the onset of the reionization process (gamma=1.56) and also presents a much wider dispersion around the mean.  Extract HI and HeII Ly-alpha absorption spectra from the simulations and fit Voigt profiles to them.  Find that the regions where helium is doubly ionized are characterized by different probability density functions of the curvature and of the Doppler b parameters of the HI Ly-alpha forest as a consequence of the bimodal temperature distribution during the early phases of HeII reionization.  The column-density ratio in HeII and HI shows a strong spatial variability.  Its probability density function rapidly evolves with time reflecting the increasing volume fraction in which ionizing radiation is harder due to the AGN contribution.  FInally show that the number density of the flux-transmission windows per unit redshift and the mean size of the dark gaps in the HeII spectra have the potential to distinguish between different reionization scenarios.

Day 451

Tuesday.

1306.5235
PAH and mid-infrared continuum emission in a z>4 submillimeter galaxy
Riechers, et al

Investigation provides an improved understanding of the energy sources that power these systems (submm galaxies), which represent the extreme and of massive galaxy formation at early cosmic times.  PAH emission at z>4 detected, strength of this emission feature is consistent with a very high SFR of ~1800 Msun/yr.  This intense starburst powers at least ~1/3 of the faint underlying 6um continuum emission, with an additional (perhaps dominant) contribution due to a power-law-like hot dust source, which is interpreted to likely be a faint, dust-obscured AGN.   Despite the strong power-law component enhancing the MIR continuum emission, the intense SB associated with the photon-dominated regions that give rise to the PA emission appears to dominate the total energy output in the IR.  Also find evidence (by comparing upper X-ray limit to 6um AGN continuum luminosity) that the previously undetected AGN in this source is Compton-thick, consistent with the finding at optical/IR wavelengths that the galaxy and its nucleus are heavily dust-obscured.

1306.5236
Star/galaxy separation at faint magnitudes: application to a simulated Dark Energy Survey
Soumagnac, Abdalla, Lahav, Kirk, ... Bertin, Rowe, Annis, Busha, ... Jarvis [!], Lin, Percival, ... Wechsler, Yanny et al

Address the problem of separating stars from the galaxies in future large photometric surveys.  Focus analysis on simulations of DES.  Derive the science requirements on star/galaxy separation, for measurement of cosmo parameters with WL and LSS probes.  Requirements are dictated by the need to control both the statistical and systematic errors on the cosmological parameters, and by PSF calibration [for WL].  Formulate the requirements in terms of the completeness and purity provided by a given star/galaxy classifier.  In order to achieve these requirements at faint magnitudes, propose a new method for star/galaxy separation.  First use PCA to outline the correlations between the objects parameters and extract from it the most relevant information.  Then use the reduced set of parameters as input to an Artificial Neural Network.  This multi-parameter approach improves upon purely morphometric classifiers (such as the classifier implemented in SExtractor), especially at faint magnitudes: it increases the purity by up to 20% for stars and by up to 12% for galaxies, at i-magnitude fainter than 23.

1306.5240
Galaxy halo truncation and giant arc surface brightness reconstruction in the cluster MACSJ1206.2-0847
Eichner, Seitz, Suyu, ... Umetsu, Zitrin, Coe, ... Koekemoer, Broadhurst, Moustakas, et al

Analyze mass distribution of this cluster, especially focusing on the halo properties of its cluster members.  The cluster appears relaxed in its X-ray emission, but has significant amounts of intracluster light which is not centrally concentrated, suggesting that galaxy-scale interactions are still ongoing despite the overall relaxed state.  The cluster lenses 12 background galaxies into multiple images and one galaxy at z=1.033 into a giant arc and its counterimage.  The multiple image positions and the surface brightness distribution (SFB) of the arc which is bent around several cluster members are sensitive to the cluster galaxy halo properties.  Model the cluster mass distribution with a NFW profile and the galaxy haloes with two parameters for the mass normalization and extent of a reference halo assuming scalings with their observed NIR-light.  Match the multiple image positions at an r.m.s. level of 0.85"; construct the SFB distribution of the arc in several filters to a remarkable accuracy based on this cluster model.  [still no mass-sheet degeneracy info!]  The length scale where the enclosed galaxy halo mass is best constrained is about 5 effective radii -- a scale in between those accessible to dynamical and field SL mass estimates on one hand and gg WL results on the other hand.  The velocity dispersion and halo size of a galaxy with m_160W,AB=19.2 or M_B,Vega=-20.7 are sigma=150 km/s and r~26pm6kpc, indicating that the halos of the cluster galaxies are tidally stripped.  Also reconstruct the unlensed source (which is smaller by a factor of ~5.8 in area), demonstrating the increase of morphological information due to lensing and conclude that this galaxy has likely SF spiral arms with a red (older) central component.

1306.5324
Density mapping with weak lensing and phase information
Szepietowski, Bacon, Dietrich, Busha, Wechsler, Melchior

Investigate reconstruction the projected density field using the complementarity of WL (weak S/N, but unbiased) and galaxy positions (high resolution, but biased tracer).  Propose a maximum-probability reconstruction of the 2d lensing convergence with a likelihood term for shear data and a prior on the Fourier phases constructed from the galaxy positions.  By considering only the phases of the galaxy field, evade the unknown value of the bias and allow it to be calibrated by lensing on a mode-by-mode basis.  Apply this method to a realistic simulated galaxy shear catalogue, find that a weak prior on phases provides a good quality reconstruction down to scales beyond l=1000, far in to the noise domain of the lensing signal alone.

1306.5333
A high erath, lunar resonant orbit for lower cost space science missions
Gangestad, Henning, Persinger, Ricker

NASA astrophysics robotic science missions often require continuous, unobstructed FoV of the celestial sphere and orbits that provide stable thermal-and attitude-control environments.  To date, the more expensive "flagship" missions use the second Earth/Sun Lagrange point (L2) approximately 1.5 million km from the Earth outside the orbit of the Moon or a "drift away" orbit to distances >10 Mkm.  A High Earth Orbit (HEO) offers similar advantages with regard to continuous, unobstructed FoV and a thermally stable environment with minimal station-keeping requirements.  The "P/2-HEO", an orbit in 2:1 resonance with the orbit of the Moon, also provides the opportunity for data downlink at orbit perigee distances close to the Earth allowing for lower-cost communications systems.  The P/2-HEO oscillates on the order of 12 years and trades orbit eccentricity for orbit inclination.  This orbit variability can be selected for optimum spacecraft performance by proper choice of the conditions using a lunar flyby for gravitational assist.  The lunar flyby and the shorter distance for science data downlink offer lower cost astrophysics missions the advantages of the more expensive L2 or "drift away" orbits.  [WMAP, Planck at L2; Kepler is in a "drift away" orbit around the Sun.]

1306.5367
Beam patterns of the five hundred metre aperture spherical telescope: optimization
Dong, Han

FAST uses adaptive spherical panels to realize the huge collecting area for radio waves.  Explore the optimal parameters for the curvature radius of spherical panels and the focal distance by comparison of the calculated beam patterns.  Show that the get the best beam shape and maximum gain, the optimal curvature radius of panels is around 300m, and a small shift of focal distance of a few cm is needed.  The aperture efficiency can be improved by ~10 at 3GHz by this small shift.  Also try to optimize the panel positioning for the best beam, and find that panel shifts of a few mm can improve the beam pattern by a similar extent.  Results indicate that the accurate control of the feed and panel position to the mm level is very crucial to the stability of FAST performance.

1306.5407
Photometric study of five open star clusters
Lata et al

As the title says; UBVRI photometry of 5 open clusters.  Fundamental cluster parameters such as FG reddening E(B-V), distance, and age have been derived by means of the observed 2 color and color-magntiude diagrams, coupled to comparisons with theoretical models.  E(B-V) values range from 0.55 to 0.74 mag, while ages derived for these clusters range from ~10 to ~500 Myr.  Studied the spatial structure, mass fraction and mass segregation effects.  The present study shows that evaporation of low mass stars from the halo of the clusters increases as they evolve.

1306.5534
Constraints on dark matter in the solar system
Pitjev, Pitjeva

Searched for and estimated the possible gravitational influence of DM in the Solar System based on the EPM 2011 planetary ephemerides using about 677k positional observations of planets and spacecraft.  Most of the observations belong to present-day ranging measurements.  Estimates of the DM density and mass at various distances from the Sun are generally overridden by their errors (sigma).  This suggests that the density of DM rho_dm, if present, is very low and is much less than the currently achieved error of these parameters.  We have found that rho_dm is less than 1.1e-20 g/cm3 at the orbital distance of Saturn, <1.4e-20 g/cm3 at the orbital distance of Mars, and <1.4e-19 g/cm3 at the orbital distance of the Earth.  Also have considered the case of a possible concentration of DM to the Solar system center.  The DM mass in the sphere within Saturn's orbit should be less than 1.7e-10 M_sun even if its possible concentration is taken into account.

1306.5544
Constraints on neutrino masses from Planck and galaxy clustering data
Giusarma, de Putter, Ho, Mena

Spectroscopic galaxy clustering measurements improve significantly the existing neutrino mass bounds from Planck data in LCDM.  Find sum m_nu < 0.39 eV at 95% CL by combining 3d PS with Planck CMB (including lensing) and WMAP9 polarization.  Robust neutrino mass constraints can be obtained without the addition of the prior on the Hubble constant from HST.    In extended cosmological scenarios with a DE fluid or with non flat geometries, galaxy clustering measurements are essential to pin down the neutrino mass bounds, providing the majority of cases better results than those obtained from the associated measurement of the Baryon Acoustic Oscillation scale only.  In the presence of a freely varying (constant) DE EoS, find sum m_nu<0.49 eV at 95% CL for the combination of the 3d PS with Planck CMB data (with lensing included) and WMAP9 polarization measurements.  This same data combination in non flat geometries provides the neutrino mass bound sum m_nu<0.35 eV at 95% CL.

1306.5730
How close is Earth to a runaway greenhouse?
Ramirez, Kopparapu, Lindner, Kasting

Recent calculations suggest that the inner edge of the habitable zone around the Sun could be as far out as 0.99 AU--much closer to the orbit of Earth than had been thought.  This reopens the question of whether future increases in atmospheric CO2 might trigger a runaway or moist greenhouse.  A runaway greenhouse implies complete ocean vaporization; a moist greenhouse implies that the stratosphere becomes wet, leading to ocean loss via hydrogen escape to space.  Previous studies had indicated that neither a moist nor a runaway greenhouse could be triggered by CO2 increases of any magnitude.  Revisit this question with a 1d climate model that includes updated absorption coefficients for CO2 and H2O, along with an improved parameterization of tropospheric relative humidity.  Find that a runaway greenhouse is still precluded.  However, a moist greenhouse could conceivably be triggered by an 11-fold increase in atmospheric CO2, and humans could be subject to fatal heat stress for CO2 increases of (4-8)-fold.  When this relative humidity parameterization is used in the habitable zone calculations, the inner edge moves inward to 0.97 AU.  Both of these calculations remain overly pessimistic, as relative humidity may increase more slowly than assumed and cloud feedback is probably negative in this temperature regime. Reexamine the lifetime of the biosphere against solar luminosity increases and show that older calculations suggesting ~0.5 Ga and 0.9 Ga as the lifetime for C3 and C4 photosynthesis are still approximately correct.  Improvements in all of these estimates could be made with a properly formulated 3d climate model that can self-consistently calculate relative humidity and cloud feedbacks.

Day 450

Monday.

1306.4980
CANDELS: the correlation between galaxy morphology and star formation activity at z~2
Lee, ... Koekemoer, Grogin, Dekel, Bell, et al

Discuss the state of assembly of the Hubble Sequence in the mix of bright galaxies at 1.4<z<=2.5 with a sample of 1671 galaxies down to H_AB~26, selected from the HST/ACS and WFC3 images of the GOODS-South field obtained as part of the GOODS and CANDELS observations.  Investigate the relationship between the SF properties and morphology using various parametric diagnostics, such as the Sersic light profile, Gini (G), M_20, Concentration (C), Asymmetry (A) and multiplicity parameters.  The sample clearly separates into massive, red and passive galaxies versus less massive, blue and SF ones, and this dichotomy correlates very well with the galaxies' morphological properties.  SF galaxies show a broad variety of morphological features, including clumpy structures and bulges mixed with faint low SB features, generally characterized by disky-type light profiles.  Passively evolving galaxies, on the other hand, very often have compact light distribution and morphology typical of today's spheroidal systems.  Also find that artificially redshifted local galaxies have a similar distribution with z~2 galaxies in a G-M_20 plane.  [!!!  useful info for shape measurements]  Visual inspection between the rest-frame optical and UV images show that there is a generally weak morphological k-correction for galaxies at z~2, but the comparison with non-parametric measures show that galaxies in the rest-frame UV are somewhat clumpier than rest-frame optical.  [more useful info!!]  Similar trends are observed in the local universe among massive galaxies, suggesting that the backbone of the Hubble sequence was already in place at z~2.

1306.4984
Detectability of the first cosmic explosions
de Souza et al

Preset a fully self-consistent simulation of a synthetic survey from the furthermost cosmic explosions.  The appearance of the first generation of stars (Pop III) in the Universe represents a critical point during cosmic evolution signaling the end of the dark ages, a period of absence of light sources.  Despite their importance, there is no confirmed detection of Pop III stars so far.  A fraction of these primordial stars are expected to die as a pair-instability SNe (PISN [can only happen in stars with a mass range from around 130 to 250 Msun and low to moderate metalicity]), and should be bright enough to be observed up to a few hundred million years after the Big Bang.  While the quest for Pop III stars continues, detailed theoretical models and computer simulations serve as a testbed for their observability.  With the upcoming NIR missions, estimates of the feasibility of detecting PISN are not only timely but imperative.  Combine state of the art cosmo and radiative sims into a complete and self-consistent framework which includes detailed features of the observational process.  Show that a dedicated observational strategy using <~8 [units?] of total allocation time of the JWST mission can provide up to 9-15 detectable PISN per year.

1306.4985
the case against large intensity fluctuations in the z~2.5 HeII Lyman-alpha forest
McQuinn, Worseck

Previous studies of the 2.2<z<2.7 HeII Lya forest measured much larger ionizing BG fluctuations than are anticipated theoretically.  Re-analyize recent HST data from the two HeII sight-lines that have been used to make these measurements, and find that the vast majority of the absorption is actually consistent with a single HeII photoionization rate.  Show that the data constrains the RMS fractional fluctuations level smoothed at 1 Mpc to be <2 and discuss why other studies had found larger fluctuations.  Our measurement is consistent with models in which quasars dominate the z=2.5 metagalactic HeII-ionizing background (but it can accomodate less compelling models), and it suggests that quasars (rather than stars) are the dominant contributor to the HI-ionizing background.  Detect a HeII transverse proximity effect that is slightly offfset in redshift from a known quasar.  Its profile and offset may indicate that the quasar turned on 10 Myr ago.

1306.4998
Review of the anisotropy working group at UHECR-2012
Deligny et al

Report on the current status for anisotropy searches in the arrival directions of UHECRs.

1306.5131
Two-point correlation function of density perturbations in a large void universe
Nishikawa, Yoo, Nakao

Study the 2-pt correlation function of density perturbations in a spherically symmetric void universe model which does not employ the Copernican principle [i.e., no special place in the Universe].  First solve perturbation equations in the inhomogeneous universe model and obtain density fluctuations by using a method of NL perturbation theory which was adopted in the previous paper.  From the obtained solutions, calculate the 2-pt correlation function and show that it has a local anisotropy at the off-center position differently from those in homogeneous and isotropic universes.  This anisotropy is caused by the tidal force in the off-center region of the spherical void.  Since no tidal force exists in homogeneous and isotropic universes, can test the inhomogeneous universe by observing statistical distortion of the 2-tp galaxy correlation function.

1306.5140
How well do we know the Halo Mass Function?
Murray, Power, Robotham

Halo mass function (HMF): a powerful probe of DM and DE models, informed by LCDM parameters.  In this letter, trace how changes in the cosmological parameters over the last decade have influenced uncertainty in our knowledge of the HMF.  Show that this uncertainty has reduced significantly since the WMAP3, but the rate of this reduction is slowing.  This is limited by uncertainty in the normalization sigma_8, whose influence is most pronounced at the high mass end of the MF.  Find that the accuracy with which we can constrain the HMF in terms of the cosmological parameters has now reached the point at which it is comparable to the scatter in HMF fitting functions.  This suggests that the power of the HMF as a precision probe of DM and DE hinges on more accurate determination of the theoretical HMF.  Assess prospects of using the HMF to differentiate between CDM and WDM models based on ongoing improvements in measurements of Omega_m, and comment briefly on optimal survey strategies for constraining DM and DE models using the HMF.

Day 449

Friday.

1306.4673
Atmospheric heat redistribution on hot Jupiters
Perez-Becker, Showman

IR light curves of transiting hot Jupiters present a trend in which the atmospheres of the hottest planets are less efficient at redistributing the stellar energy absorbed on their daysides--and thus have a larger day-night temperature contrast--than colder planets.  No predictive atmospheric model has been published that identifies which dynamical mechanisms determine the atmospheric heat redistribution efficiently on tidally locked exoplanets.  Present a two-layer shallow water model of the atmospheric dynamics on synchronously rotating planets that explains the observed trend.  Model shows that planets with weak friction and weak irradiation exhibit a banded zonal flow with minimal day-night temperature differences, while models with strong irradiation and/or strong friction exhibit a day-night flow pattern with order-unity fractional day-night temperature differences.  To interpret the model, develop a scaling theory that shows that the timescale for gravity waves to propagate horizontally over planetary scales, t_wave, plays a dominant role in controlling the transition from small to large temperature contrasts.  This implies that hiat redistribution is governed by a wave-like process, similar to the one responsible for the weak temerature gradients in the Earth's tropics.  When atmospheric drag can be neglected, the transition from small to large day-night temperature contrasts occurs when t_wave ~ sqrt(t_rad/Omega), where t_rad is the radiative relaxation time, and Omega is the planetary rotation frequency.  Alternatively, this transition criterion can be expressed as t_rad ~ t_vert, where t_vert is the timescale for a fluid parcel to move vertically over the difference in day-night thickness.  These results subsume the commonly used timescale comparison for estimating heat redistribution efficiency between t_rad and the global horizontal advection timescale, t_adv.

1306.4674
ARCONS: a 2024 pixel optical through near-IR Cryogenic imaging spectrophotometer
Mazin et al

Array Camera for Optical to Near-IR Spectrophotometry (design, construction and commissioning results).  Based on Microwae Kinetic Inductance Detectors (MKIDs), a cryogenic detector capable of detecting single photons and measuring their energy without filters or gratings, similar to an X-ray microcalorimeter.  MKIDs are nearly ideal, noiseless photon detectors, as they do not suffer from read noise or dark current and have nearly perfect cosmic ray rejection.  ARCONS is an integral field spectrograph (IFS) containing a lens-coupled 2024 pixel MKID array yielding a 20"x20" FoV, and has been deployed on the Palomar 200" and Lick 120" telescopes for 24 nights of observing.  Present initial results showing that ARCONS and its MKID arrays are now a fully operational and powerful tool for astronomical observations.

1306.4675
Source-position transformation -- an approximate invariance in strong gravitational lensing
Schneider, Sluse

Obstacle for GL in determine accurate masses of deflectors, or to determine precise estimates for the Hubble constant, is the degeneracy of lensing observables with respect to the mass-sheet transformation (MST).  The MST is a global modification of the mass distribution which leaves all image positions, shapes and flux ratios invariant, but which changes the time delay.  Show that another global transformation of lensing mass distributions exists which almost leaves image positions and flux ratios invariant, and of which the MST is a special case.  Whereas for axi-symmetric lenses this source position transformation exactly reproduces all strong lensing observables, it does so only approximately for more general lens situations.  Provide crude estimates for the accuracy with which the transformed mass distribution can reproduce the same image positions as the original lens model, and present an illustrative example of its performance.  This new invariance transformation most likely is the reason why the same SL information can be accounted for with rather different mass models.

1306.4684
Cosmological parameters from weak lensing power spectrum and bispectrum tomography: including the non-Gaussian errors
Kayo, Takada

Re-examine a genuine power of WL bispectrum tomography for constraining cosmological parameters, when combined with the power spectrum tomography, based on the Fisher information matrix formalism.  To account for the full information at 2- and 3-pt levels, include all the PS and bispectrum information built from all-scales (up to L_max=2000, fiducial).  For the parameter forecast, use the halo model approach in Kay, Takada & Jain (2013) to model the non-Gaussian error covariances as well as the cross-covariance between the PS and the bispectrum, including the halo sample variance or the NL version of beat-coupling.  Find that adding the bispectrum information leads to about 60% improvement in the DE FoM compared to the lensing PS tomography alone, for 3 redshift-bin tomography and Subaru-type survey probing galaxies at z_s~1.  The improvement is equivalent to a 1.6 larger survey area.  Thus results show that the bispectrum or more generally any 3-pt correlation based statistics carries complementary information on cosmological parameters to the PS.  However, the improvement is modest compared to the previous claim derived using the Gaussian error assumption, and therefore results imply less additional information in even higher-order moments such as the 4-pt correlation function.

1306.4686
Cosmological constraints from galaxy clustering and the mass-to-number ratio of galaxy clusters: marginalizing over the physics of galaxy formation
Reddick, Tinker, Wechsler, Lu

Many cosmo info rely on connection between galaxies and DM.  The distribution of galaxies is dependent on their formation and evolution as well as the cosmological model, and galaxy formation is still not a well-constrined process.  Thus, methods that probe cosmology using galaxies as a tracer for DM must be able to accurately estimate the cosmological parameters without knowing the details of galaxy formation a priori.  Apply this reasoning to the method of obtaining Omega_m and sigma_8 from galaxy clustering combined with the mass-to-number ratio of galaxy clusters.  To test the sensitivity of this method to variations due to galaxy formation, consider several different [SAM?] models applied to the same cosmological DM simulation.  The cosmological parameters are then estimated using the observables in each model, marginalizing over the parameters of the HOD.  Find that for models where the galaxies can be well represented by a parameterized HOD, this method can successfully extract the desired cosmological parameters for a wide range of galaxy formation prescriptions.

1306.4732
Cosmology from gravitational lens time delays and Planck data
Suyu, Treu, Hilbert, Sonnenfeld, Auger, Blandford, Collett, Courbin, Fassnacht, Koopmans, Marshall, Meylan, Spiniello, Tewes

With LCDM, Planck data points to a H0 that is in tension with that measured by SL time delays and by local distance ladder.  Could be from systematics, or (if systematics ruled out) a departure from LCDM, introducing e.g. a modest amount of spatial curvature, or a non-trivial DE EoS.  Present analysis of RXJ1131-1231 with improvement in systematics analysis in the lens model density profile.  Use more flexible gravitational lens models with baryonic and DM components, and found that the HST image with thousands of pixels within Einstein ring contains sufficient information to constrain the more flexible models.  The total uncertainty on the time-delay distance is 6.5% for a single system, including the uncertainty over the two lens models considered.  Thus proceed to combine the improved time-delay distance measurements with WMAP9 and Planck posteriors.  In an open LCDM model, the data for RXJ1131-1231 in combination with Planck favor a flat universe with Omega_k=-0.01pm0.02 (68%CL).  In a flat wCDM model, the combination of SL data and Planck yields w=-1.55pm0.2 (68% CL).  [no mass sheet degeneracy mentioned!  Mass sheet degeneracy still allows for the lens modeling to succeed, but with degenerate H0 values, so HST pixels and images are irrelevant with regards to this degeneracy.]

1306.4736
A curious relation between the flat cosmological model and the elliptic integral of the first kind
Meszaros, Ripa

Present luminosity distance-redshift relation for non-zero cosmological constant (for zero cosmological constant, relation is given by standard functions).  Use definite integrals.  The integration ends in the elliptic integral of the first kind.  The results shows that no numerical integration is needed for the non-zero cosmological constant, if the universe is spatially flat.

1306.4786
A new way to measure supermassive black hole spin in accretion disc dominated active galaxies
Done, Jin, Middleton, Ward

Show that disc continuum fitting can be used to constrain BH spin in a subclass of Narrow Line Seyfert 1 (NLS1) AGN as their low mass and high mass accretion rate [?] means that the disc peaks at energies just below the soft X-ray bandpass.  Apply the technique to the NLS1 PG1244+026, where the optical/UV/X-ray spectrum is consistent with being dominated by a standard disc component.  This gives a best estimate for BH spin which is low, with a firm upper limit of a*<0.86.  This contrasts with the recent X-ray determinations of (close to) maximal BH spin in other NLS1 based on relativistic smearing of the Fe profile.  While data does not have sufficient statistics at high energy to give a good measure of BH spin from the Fe line profile, cosmological simulations predict that BHs with similar masses have similar growth histories and so should have similar spins.  

1306.4963
Galaxy and mass assembly (GAMA): galaxy radial alignments in GAMA groups
Schneider, Cole, Frenk, Kelvin, Mandelbaum, ... et al

Constrain distributions of projected radial alignment angles of satellite galaxy shapes within GAMA group catalogue.  Identify the galaxy groups using spectro-z and measure galaxy projected ellipticities from SDSS images.  With a sample of 3,850 groups with 13,655 satellite galaxies with high quality shape measurements, find a less than 2-sigma signal of radial alignments in the mean projected ellipticity components and the projected position angle when using galaxy shape estimates optimized for WL measurements.  Radial alignment measurement increases to greater than 3 sigma significance relative to the expectation for no alignments if we use 2d Sersic model fits to define galaxy orientations.  Weak measurement of radial alignments is in conflict with predictions from DM N-body simulations, which we interpret as evidence for large mis-alignments of baryons and DM in group and cluster satellites.  Within uncertainties, that are dominated by the small sample size, find only weak and marginally significant trends of the radial alignment angle distributions on projected distance from the group center, host halo mass, and redshift that could be consistent with a tidal torquing mechanism for radial alignments.  Using lensing optimized shape estimators, estimate that IA of galaxy group members may contribute a systematic error to the mean differential projected surface mass density of groups inferred from WL observations by -1 pm 20% at scales around 300 kpc/h from the group centre assuming a photometric redshift RMS error of 10%, and given our group sample with median redshift of 0.17 and median virial masses 1e13 Msun/h.

1306.4968
The ALHANBRA survey: Bayesian photometric redshifts with 23 bands for 3 squared degrees
Molino, Benitez, et al

Advance Large Homogeneous Area Medium Band Redshift Astronomical (ALHAMBRA) survey has observed 8 different regions of the sky, including COSMOS, DEEP2, ELAIS, GOODS-N, SDSS and Groth fields using 20 continuous ~300A width filters covering the optical range, combining with deep JHKs imaging.  Observations at Calar Alto 3.5M telescope, 0.25 sq deg FoV with optical and NIR instruments, ~700 hrs on-target science images.  Photometric system designed to maximize the effective depth of the survey in terms of accurate spectral-type and photo-zs estimation along the capability of identification of relatively faint emission lines.  Present multicolor photometry and photo-zs for ~438k galaxies, detected in synthetic F814W images, down to I~24.5 AB (takes in to account realistic noise estimates, and correcting PSF and aperture effects with software).  The photometric ZP have been calibrated using stellar transformation equations and refined internally, using a new technique based on the highly robust photometric redshifts measured for emission line galaxies.  Calculate photometric redshifts with the BPZ2 code, which includes new empirically calibrated templates and priors.  Photo-zs have precision of dz/(1+z_s)=1% for I<22.5 and 1.4% for 22.5<I<24.5.  Precisions of less than 0.5% are reached for the brighter spectro sample, showing the potential of medium-band photometric surveys.  The global P(z) shows a mean redshift <z>=0.56 for I<22.5 AB and <z>=0.86 for I<24.5AB.  The data presented here covers and effective area of 2.79 sq. deg, split into 14 strips of 5.5'x15.5' and represents ~32 hrs of on-target.

Day 448

Thursday.

1306.4195
The star formation history of the solar neighbourhood from the white dwarf luminosity function
Rowell
The termination in the WD LF is a standard diagnostic tool for measuring the total age of nearby stellar populations.  In this paper, an algorithm is presented for inverting the full WD LF to obtain a maximum likelihood estimate of the time varying SFR of the host stellar population.  Tests with synthetic data demonstrate that the algorithm converges over a wide class of underlying SFR forms.  The algorithm successfully estimates the moving average SFR as a function of lookback time in the presence of realistic measurement noise, though suffers from degeneracies around discontinuities in the underlying SFR.  The inversion results are most sensitive to the choice of WD cooling models, with the models produced by different groups giving quite different results.  The results are relatively insensitive to the progenitor metallicity, IMF, initial-final mass relation and ratio of H/He atmosphere WDs.  Application to two independent determinations of the Solar neighborhood WD LF give similar results.  The SFR has a bimodal form, with broad peaks at 2-3 Gyr and 7-9 Gyr in the past, separated by a significant lull of magnitude 30-90% depending on choice of cooling models.  The onset of SF occurs around 8-10 Gyr ago.  The total integrated SFR is ~0.014 stars/pc3 in the Solar neighbourbood, for stars more massive than 0.6 M_sun.

1306.4157
Galaxy redshift surveys with sparse sampling
Chiang et al

A competitive study of the 3d-survey of galaxies require a large volume (V_survey ~ 10 Gpc^3), and thus expensive.  A "sparse sampling" method offers a more affordable solution to this problem: within a survey footprint covering a given survey volume, observed only a fraction of the volume.  The distribution of observed regions should be chosen such that their separation is smaller than the length scale corresponding to the wavenumber of interest.  Then one can recover the PS of galaxies with precision expected for a survey covering a volume of V_survey (rather than the volume of the sum of observed regions) with the number density of galaxies given by the total number of observed galaxies divided by V_survey (rather than the number density of galaxies within an observed region).  Find that regularly-spaced sampling yields an unbiased PS with no window function effect, and deviations from regularly-spaced sampling, which are unavoidable in realistic surveys, introduce calculable window function effects and increase the uncertainties of the recovered PS.  Method is general, but discussed in terms of Hobby-Eberly telescope DE experiment.

1306.4415
The GRB redshift distribution: implications for abundance evolution, star formation, and cosmology
Wei et al

LGRBs from Swift do not trace the SFH in LCDM; confirm that the latest example of GRBs reveals an increasing evolution in the GRB rate relative to the SFR at high redshifts.  [...Metallicity evolution may explain this, but doesn't quite work.  Assume a different cosmology that makes it work....]  Assuming that the GRB rate is related to the SFR and an evolving metallicity, find that the GRB data constrain the slope of the high-z SFR to be -4.6.  With this updated SFH, find that in the R_h=ct universe, the observed redshift distribution can also be fitted very well.

1306.4312
Dust in the polar region as a major contributor to the IR emission of AGN
Hoenig, Kishimoto, et al

As the title says.

1306.4319
Baryons do trace dark matter 380,000 years after the big bang: search for compensated isocurvature perturbations with WMAP 9-year data
Grin, Hanson, Holder, Dore, Kamionkowski

Primordial isocurvature fluctuations between photons and either neutrinos or non-relativistic species such as baryons or DM are known to be sub-dominant to adiabatic fluctuations.  However, perturbations in the relative densities of baryons and DM (known as compensated isocurvature perturbations, or CIPs) are poorly constrained.  CIPs leave no imprint in the CMB on observable scales, at least at linear order in their amplitude and zeroth order in the amplitude of adiabatic perturbations.  It is thus not yet empirically known if baryons trace dark matter at the surface of last scattering.  If CIPs exist, they would spatially modulate the Silk damping scale and acoustic horizon, causing distinct fluctuations in the CMB temperature/polarization PS across the sky: this effect is first order in both the CIP and adiabatic mode amplitudes.  Here, temperature data from the WMAP are used to conduct the first CMB-based observational search for CIPs, using off-diagonal correlations and the CMB trispectrum.  Reconstruction noise from WL and point sources is shown to be negligible for this data set.  No evidence for CIPs is observed, and a 95%-confidence upper limit of 1.1e-2 is imposed to the amplitude of a scale-invariant CIP PS.  This limit agrees with CIP sensitivity forecasts for WMAP, and is competitive with smaller scale constraints from measurements of the baryon fraction in galaxy clusters.  It is shown that the root-mean squared CIP amplitude on 5-100 deg scales is smaller than 0.07-0.17 (depending on the scale) at the 95% confidence level.  Temperature data from the Planck satellite will provide an even more sensitive probe for the existence of CIPs, as will the upcoming ACTPol and SPTPol experiments on smaller angular scales.

1306.4328
The massive satellite population of Milky-Way sized galaxies
Rodriguez-Puebla, Avila-Reese, Drory

Occupational distributions for satellite galaxies m_s>4e7 Msun around MW-sized hosts are presented and used to predict the internal dynamics of these satellites.  Create galaxy group mock catalog base on (sub)halo-to-stellar mass relations constrained with observations; the stellar MF of centrals and satellites, and the 2-t correlation function.  6.6% of MW-s galaxies host 2 sats in the mass range of the SMC and LMC.  THe probabilities of the MW-s galaixes to have 1 sat>= the LMC or 2 sats >= te SMC or 3 sats >= Sgr are ~0.26, 0.14, and 0.14, respectively.  MW-s hosting 3 sats >= Sgr (as the MW) are among the most common cases.  However, the most and 2nd most massive sats in these systems are <LMC and SMC by ~0.7 and 0.8 dex.  The N(>m_s) for MW-s galaxies is broad, the case of the MW being of low frequency but not an outlier.  The Mh of MW-s galaxies correlates only weakly with N(>ms).  THen, it is not possible to accurately determine the MW halo mass by mans of N(>ms); constrain a lower limit 1e12 Msun at 1sig level.  Analysis strongly suggests that the abundance of massive subhalos agree with the abundance of massive sats in al MW-s hosts, i.e., there is not a (massive) sat missing problem for the LCDM.  However, confirm that the max circular vel, vmax, of the subhalos of sats ms<1e8 Msun is systematically larger than the vmax inferred from current observational studies of the MW bright dwarf sats; at difference of previous works, this conclusion is based on an analysis of the overall population of MW-s galaxies.  Some pieces of evidence suggest that the issue could refer only to sat dwarfs but not to central dwarfs; then, environmental processes associated to dwarfs inside host halos combined with SN-driven core expansion should be at the basis of the lowering of vmax.

1306.4337
The build-up of nuclear stellar cusps in extreme starburst galaxies and major mergers
Haan et al

Nuclear stellar cusps are defined as central excess light component in the stellar light profiles of galaxies and are suggested to be stellar relics of intense compact starbursts in the central ~100-500pc region of gas-rich major mergers.  Probe the build-up of nuclear cusps during the actual starburst phase for a complete sample of LIRG systems (85 LIRGs with L_IR=1e11.4-12.5 L_sun) in the GOALS sample.  Cusp properties are derived via 2-d fitting of the nuclear stellar light imaged in the NIR by HST and have been combined with MIR diagnostics for AGN/SB characterization.  Find that nuclear stellar cusps are resolved in 76% of LIRGs (merger and non-interacting galaxies).  The cusp strength and luminosity increases with FIR luminosity (excluding AGN) and merger state, confirming theoretical models that starburst activity is associated with the build-up of nuclear stellar cusps.  Evidence for ultra compact nuclear starbursts is found in ~13% of LIRGs, which have a strong unresolved central NIR light component but no significant contribution of an AGN.  The nuclear NIR surface density (measured within 1 kpc radius) increases by a factor of ~5 towards late merger stages.  A careful comparison to local early type galaxies with comparable masses reveals (a) that local (U)LIRGs have a significantly larger cusp fraction and (b) that the majority of the cusp LIRGs have host galaxy luminosities (H-band) similar to core ellitpicals which is roughly one order in magnitude larger than for cusp ellipticals.

1306.4663
Modeling the pollution of pristine gas in the early universe
Pan et al

Theoretical and numerical investigation of the pollution of pristine gas in turbulent flows, designed to provide new tools for modeling the evolution of the 1st generation of stars.  Cooling is different ing as with a metallicity below a critical value Z_c (1e-6~1e-3 Z_sun).  Z_c is much smaller than the typical average metallicity <Z>; thus the mixing efficiency of the pristine gas in the interstellar medium plays a crucial role in the transition from Pop III to normal star formation.  The small critical value Z_c corresponds to the far left tail of the probability distribution function of the metallicity.  Based on closure models for the PDF formation of turbulent mixing, derive equations for the fraction of gas, P, lying below Z_c, in compressible turbulence.  Simulation show that the evolution of the fraction P can be well approximated by a generalized self-convolution model, which predicts dP/dt = -n/tau_con P(1-P^(1/n)), where n is a measure of the locality of the PDF convolution and the timescale tau-con is determined by the rate at which turbulence stretches the pollutants.  Using a suite of simulations with Mach numbers ranging from M=0.9 to 6.2, provide accurate fits to n and tau_con as a function of M, Z_c /<Z>, and the scale L_p at which pollutants are added to the flow.  For P>0.9, mixing occurs only in the regions surrounding the pollutants, such that n=1. For smaller P, n is larger as mixing becomes more global.  Show how the results can be used to construct one-zone models for the evolution of Pop III stars in a single high-redshift galaxy, as well as subgrid models for tracking the evolution of the first stars in large cosmological simulations.