Day 568

Saturday.  Two full weeks and a few days behind.  Sunday.

1312.2576
Lensed Type Ia supernovae as probes of cluster mass models
Nordin, Rubin, Richard, Rykoff, Aldering, Amanulla, .. Fakhouri, … Meyers, Perlmutter, et al

First pilot study to see whether standardizable candles can be used to calibrate cluster mass maps created from SL observations (uses 3 magnified SNIa behind massive CLASH clusters).  Such calibrations will be crucial when next generation HST cluster surveys (e.g. FRONTIER) provide magnification maps that will, in turn, form the basis for the exploration of the high z universe.  Demonstrate that SNe can be used as "test beams" for this purpose.  Use a combination of spectroscopic and photometric methods to classify the SNe and then determine the SN amplification factors using the SALT2/Union2.1 framework.  Find SNe with significant amplification, up to a factor of 1.7 at ~5 sigma significance for SN-L2 behind MACSJ1720.  Initially conducted theist as a blind study to avoid find tuning of parameters, and found a mean amplification difference between SNe and the cluster lensing models of 0.09 pm0.09(stat) pm0.05(sys) mag.These constraints are impressive, especially given the small sample size, and suggest no tension between cluster mass models and high-z standardized SN Ia [but the cluster mass model differs for each cluster, though…?  There is no standardized cluster mass modeling, I don't think.].  However, the measured statistical dispersion of sigma_mu=0.21 mag appeared large compared to the dispersion expected based on statistical uncertainties (0.14). FUrther work with the SN and cluster lensing models, post unblinding, reduced the measured dispersion to sigma_mu=0.12 mag.  This demonstrates that an explicit choice should be made and reported as to whether the SNe are used unblinded to improved the model, or blinded to test the model.  As the lensed SN samples grow larger, this technique will allow improved constraints on mass sheets and assumptions regarding the structure of the DM halo.

1312.2583
Using gas kinematics to constrain 3d model of disks: IC 2531
Eigenbrot, Bershady

Deep, longslit spectra of the nearby edge-on galaxy IC 2531 to obtain gas kinematics out to 5 radial scale-lengths (40 kpc) and 4 vertical scale-heights (1.7 kpc).  The large vertical range spanned by the data offers unique leverage to constrain 3d models.  The shape of the observed emission-line profiles offer insights to LoS density distributions in the disk; discuss the possibility of disk-flaring in the ionized gas.  Begin to quantify measurements of line shape to allow model galaxies to be compared to data across all radii and heights simultaneously.

1312.2584
Spatially resolved LMC star formation history: I. outside in evolution of the outer LMC disk
Meschin et al

Study the evolution of 3 fields in the outer LMC disk Rgc=3.5-6.2 kpc.  Their SFH indicates a stellar populations gradient such that younger stellar populations are more centrally concentrated.  Identify 2 main SF epochs, separated by a period of lower activity between ~7 and ~4 Gyr ago.  Their relative importance varies from a similar mount of stars formed in the two epochs in the innermost field, to only 40% of the stars formed in the more recent epoch in the outermost field.  The young SF epoch continues to the present time in the innermost field, but lasted only till ~0.8 and 1.3 Gyr ago at Rgc=5.5 deg and 7.1 deg, respectively.  This gradient is correlated with the measured HI column density and implies an outside-in quenching of the SF, possibly related to a variation of the size of the HI disk.  This could either result from gas depletion due to SF or ram-pressure stripping, or from the compression of the gas disk as ram-pressure from the MW halo acted on the LMC ISM.   The latter two situations may have occurred when the LMC first approached the MW.

1312.2587
On the mass of the local group
Gonzalez, Kravtsov, Gnedin

Use proper motion measurements of the tangential velocity of M31, along with its radial velocity and distance, to derive the likelihood of the sum of halo masses of the MW and M31.  This is done using a simple halo pairs in the Bolshoi cosmological simulation of LCDM cosmology selected to match properties and environment of the LG.  The resulting likelihood gives estimate of the sum of masses of M_MW,200 + M_M31,200 = 2.40-1.05+1.95 e12 Msun (90% CL).  This estimate is consistent with individual mass estimates for the MW and M31 and is (albeit somewhat on the low side) also with the mass estimated using the timing argument [?].  Show that although the timing argument is unbiased on average for all pairs, for pairs constrained to have radial and tangential velocities similar to that of the LG, the argument overestimates the sum of masses by a factor of 1.6.  Using similar technique estimate the total DM mass enclosed within 1 Mpc from the LG barycenter to be M_LG(r<1 Mpc)=4.2-2.0+3.4 e12 Msun (90% CL).

1312.2593
A tale of two redshifts
Bassett, Fantaye, Hlozek, Saibu, Smith

Observed redshift z_o and model redshift z may be different, and a simple remapping z= a_1 z_o + a_2 z_o^2 allows pretty good fitting to the SNe data of a non-LCDM model redshift.  But redshift remapping leaves a distinct observational signature which allow both strong constraints on remapping and reaffirmation of acceleration when current d_A, d_L and H(z) data are combined.  Remapping can significantly change the inferred values of data points, blurring the line between theory and data and creating tension between different estimates of parameters such as H_0.  While constraining specific models with z remapping requires careful analysis, results suggest it provides a new test of back reaction and non-standard physics.

1312.2595
Overlapping inflow events as catalysts for supermassive black hole growth
Carmona-Loaiza et al

Aim: to explore how the interaction between the rotating, infalling gas shells and the primitive large scale (~10pc) disk around a SMBH redistributes the angular momentum on scales close  to the BH's sphere of influence.  Angular momentum redistribution via hydrodynamical shocks leads to inflows of gas across the inner boundary, enhancing the inflow rate by more than 2-3 orders of magnitude.  In all cases, the gas inflow rate across they inner parsec is higher than in the absence of the interaction, and the orientation of the angular momentum of the flow in the region changes with time due to gas mixing.  Warped discs or nested misaligned rings form depending on the angular momentum content of the in falling shell relative to the disc.  In the cases in which the shell falls in near counter-rotation, part of the resulting flows settle into an inner dense disc which becomes more susceptible to mass transfer.

1312.2620
Magnetic fields in cosmological simulations of disk galaxies
Pakmor, Marinacci, Springel

Observationally, B-fields reach equipartition with thermal energy and CRs in the ISM of disk galaxies such as the MW.  However, thus far cosmological simulations of the formation and evolution of galaxies have usually neglected B-fields.  Employ the moving-mesh code Arepo to follow for the first time the formation and evolution of a MW-like disk galaxy in its full cosmological context while taking into account B-fields.  Find that a prescribed tiny B-field seed field grows exponentially by a small-scale dynamo [in a star or what?] until it saturates around z=4 with a magnetic energy of ~10% of the kinetic energy in the center of the galaxies main progenitor halo.  By z=2, a well-defined gaseous disk forms in which the B-field is further amplified by a differential rotation, until it saturates at an average field strength of ~6 micro Gauss in the disk plane.  In this phase, the B-field is transferred from a chaotic small-scale field to an ordered large-scale field coherent on scales comparable to the disk radius.  The final B-field strength, its radial profile and the stellar structure of the disk compare well with observational data.  A minor merger temporarily increases the B-field strength by about a factor of 2, before it quickly decays back into its saturation value.  Results are highly insensitive to the initial seed field strength and suggest that the large-scale B-field in spiral galaxies can be explained as a result of the cosmic structure formation process.

1312.2871
Micro-arcsecond radio astrometry
Reid, Honma

Astrometry: association of sources detected at different times or wavelengths, and distances are essential to estimate the size, luminosity, has, and ages of most objects.  VLBI at radio, with diffraction-limited imaging at sub-milliarcsec resolution, has long held the promise of micro-arcsecond astrometry.  However, only in the past decade has this been routinely achieved.  Currently, parallaxes for sources across the MW are being measured with ~10 uas accuracy and proper motions of galaxies are being determined with accuracies of ~1 uas/y.  The astrophysical applications of these measurements cover many fields, including SF, evolved stars, stellar and SMBHs, galactic structure, the history and fate of the Local Group, the Hubble constant, and tests of GR.  This review summarizes the methods used and the astrophysical applications of micro-acrsecond radio astrometry.

1312.2927
The smallest particles in Saturn's A and C rings
Harbison, Nicholson, Hedman

Contrary to previous optical and IR work which impiled that there were few particles in the A ring <1cm, radio occultations of Saturn's main rings suggest a power law particle size-distribuiton down to sizes of order 1 cm.  Lack of optical depth variations between UV and NIR wavelengths indicate a lack of micron-sized particles.  A cutoff where the particle-size distribution turns over must exist, but the position and shape of it is not clear from existing studies.  From forward scattered light in the A and C rings and a model of diffraction by ring particles, estimate the minimum particle size using a truncated power-law size distribution.  C ring shows minimum size of ~4mm with a power law index of q=3.1 and maximum of 10m.  The A ring shows a similar level of scattered flux, but modeling is complicated by the presence of self-gravity wakes and higher optical depths.  If z<3, the A ring model requires a minimum particle size <1mm to be consistent with VIMS observations.  

1312.2947
The MICE grad challenge light cone simulation III: Galaxy lensing mocks from all-sky lensing maps
Fosalba, Gaztanaga, Castander, Crocce

MICE-GC build halo and galaxy catalogs using HOD an halo abundance matching.  Given its large volume and fine mass resolution, the MICE-GC simulation also allows an accurate modeling of the lensing observables from upcoming wide and deep galaxy surveys.  In this paper, describe the construction of all-sky lensing maps, following the "onion universe" approach, and discuss their propeties in the light cone up to z=1.4 with sub-arcmin spatial resolution  By comparing the convergence PS in the MICE-GC to lower mass-resolution (1e11 Msun particles) simulations, find that resolution effects are at the 5% level for multipoles l~1e3 and 20% of l~1e4.  Resolution effects have a much lower impact on the simulation, as shown by comparing the MICE-GC to recent numerical fits.  Use the all-sky lensing maps to model galaxy lensing properties, such as the convergence, shear, and lensed magnitudes and positions, and validate them thoroughly using galaxy shear auto and cross-correlations in harmonic and configuration space.  Results show that the galaxy lensing mocks here presented can be used to accurately model lensing observables down to arc minute scales.

1312.2952
Constraining the origin of the rising cosmic ray positron fraction with the boron-to-carbon ratio
Cholis, Hooper

The rapid rise in the CR positron fraction above 10 GeV, as measured by PAMELA and AMS, suggests the existence of nearby primary sources of HE positrons, such as pulsars or annihilating/decaying DM.  In contrast, the spectrum of secondary positrons produced through the collisions of CRs in the ISM is predicted to fall rapidly with energy, and thus is unable to account of the observed rise.  It has been proposed, however, that secondary positrons could be produced and then accelerated in nearby SN remnants, potentially explaining the observed rise, without the need of primary positron sources.  Yet, if secondary positrons are accelerated in such shocks, other secondary CR species (such as B nuclei, and antiprotons) will also be created, leading to rises in the B/C and antiproton-to-proton ratios. The measurements of the B/C ratio by PAMELA and AMS collaborations, however, show no sign of such a rise.  With this new data in head, revisit the secondary acceleration scenario for the rising positron fraction.  Assuming that the same SN remnants accelerate both light nuclei (protons, He) and heavier CR species, find that no more than ~25% of the observed rise in the positron fraction can result from this mechanism (at the 95% CL).

1312.3015
Measurement of galaxy cluster integrated Comptonization and mass scaling relations with the south pole telescope
Saliwanchik et al

A new method for measuring the integrated Comptonization (YSZ) from SPT SZ multi-band data; characterize the sample of galaxy clusters detected.  Test this method on simulated cluster observations and verify that it can accurately recover cluster parameters with negligible bias.  In realistic simulations of an SPT-like survey, with realization of CMB anisotropy, point sources, and atmosphere and instrumental noise at typical SPT-SZ survey levels, find that YSZ is most accurately determined in a aperture comparable to the SPT beam size.  Demonstrate the utility of this method to measure YZZ and to constrain mass scaling relations using X-ray mass estimates for a sample f 18 galaxy clusters from the SPT-SZ survey.  Measuring YSZ within a 0.75' radius aperture, find an intrinsic log-normal scatter of 21 pm 11% in YSZ at a fixed mass.  Measuring YSZ within a 0.3 Mpc projected radius (equivalent to 0.75' at the survey median z = 0.6) find a scatter of 26pm9%.  Prior to this study, the SPT observable found to have the lowest scatter with mass was cluster detection significance.  Demonstrate, from both simulations and SPT observed clusters, that YSZ measured within an aperture comparable to the SPT beam size is equivalent, in terms of scatter with cluster mass, to SPT cluster detection significance.

1312.3029
An atlas of galaxy spectral energy distributions from the ultraviolet to the mid-infrared
Brown, Moustakas, … et al

Present atlas of 129 SEDs for nearby galaxies, with wavelength coverage from UV to MIR.  Atlas spans ellipticals, spirals, merging galaxies, blue compact dwarfs, and luminous IR galaxies (LIRGs).  Combined ground-based optical drift-scan spectrophotometry with IR spectroscopy from Spitzer and Akari, with gaps in spectra coverage being filled using MAGPHYS SED models.  The spectroscopy and models were normalized, constrained and verified with matched-aperture photometry measured from Swift, GALEX, SDSS, 2MASS, Spitzer and WISE images. The availability of 26 photometric bands allowed identification and mitigation of systematic errors present in the data.  Comparison of SEDs with other template libraries and the observed colors of galaxies indicates that there are smaller systematic errors than existing atlases, while spanning a broader range of galaxy types.  Relative to prior literature, this atlas will provide improved K-corrections, photometric redshifts and SFR calibrations.

1312.3117
The mutual interaction between population III stars and self-annihilating dark matter
Stacy, Pawlik, Bromm, Loeb

Use cosmo-sims of high-z mini halos to investigate the effect of DM annihilation (DMA) on the collapse of primordial gas.  Numerically investigate the evolution of the gas as it assembles in a Pop III stellar disk.  Find that when DMA effects are neglected, the disk undergoes multiple fragmentations events beginning at ~500 yr after the appearance of the first protostar.  On the other hand, DMA heating and ionization of the gas speeds the initial collapse of gas to protostellar densities and also affects the stability of the developing disk against fragmentation, depending on the DM distribution.  Compare the evolution when the DM density is modeled with an analytical DM profile which remains centrally peaked, and when the DM profile is simulated using N-body particles (the 'live' DM halo).  When utilizing the analytical DM profile, DMA suppresses disk fragmentation for ~3500 yr after the first protostar forms, in agreement with earlier work.  However, when using a 'live' DM halo, the central DM density peak is gradually flattened due to the mutual interaction between the DM and the rotating gaseous disk, reducing the effects of DMA on the gas, and enabling secondary protostars of mass ~1 Msun to be formed within ~900 yr.  These simulations demonstrate that DMA is ineffective in suppressing gas collapse and subsequent fragmentation, rendering the formation of long-lived dark stars unlikely [do they mean DM-only stars?  That all DM halo will have significant baryonic components?].  However, DMA effects may still be significant in the early collapse and disk formation phase of primordial gas evolution.

1312.3133
The environmental dependence of neutral hydrogen in the GIMIC simulations
Cunnama et al

Use Galaxies-Intergalactic Medium Interaction Calculation (GIMIC) cosmo hydrosim at z=0 to study the distribution and environmental dependence of neutral Hydrogen (HI) gas in the outskirts of simulated galaxies.  This gas can currently be probed directly in, e.g., Lya absorption via the observation of BG quasars.  Radio facilities, such as SKA, will provide a complementary probe of the diffuse HI in emission and will constrain the physics underpinning the complex interplay between accretion and feedback mechanisms which affect the IGM.  Extract a sample of 488 galaxies from a re-simulation of the average cosmic density GIMIC region.  Estimate the HI content of these galaxies and the surrounding IGM within which they reside.  Investigate the average HI radial profiles by stacking the individual profiles according to both mass and environment.  Find high HI column densities at large impact parameters in group environments and markedly lower HI densities for non-group galaxies.  Suggest that these results likely arise from the combined effects of ram pressure stripping and tidal interactions present in group environments.

1312.3181
Trigonometric parallaxes to star-forming regions within 4 kpc of the galactic center
Sanna et al

Report 4 trigonometric parallaxes for high-mass SF regions within 4 kpc of the Galactic center; associated with large-scale features in CO and HI longitude-velocity diagrams.  Outline some major features of the inner MW: the Connecting arm, the nearing and far 3kpc arms, and the Norma arm.  The connecting erin in the first Galactic quadrant lies closer to the Glactic center than the far 3 kpc arm and is offset by the long-bar's major axis near its leading edge, supporting the presence of an inner Lindbald resonance.  Assuming the 3 kpc arms are a continuous physical structure, the relative Galactocentric distance of its near and far sides suggests highly elliptical streamlines of gas around the bar(s) and a bar coronation radius, r_CR > 3.6 kpc.  At a Galactic longitude near 10 deg and a hello centric distance of about 5 kpc, the near 3 kpc arm and the Norma arm intersect on a face-on view of the Galaxy, while passing at different Galactic latitudes.  Provide an accurate distance measurement to the W31 SF complex of 4.95pm0.5 kpc from the Sun, which associates it with at bright CO feature belonging to the near 3 kpc arm.
1312.3223
Formation of molecular clouds and global conditions for star formation
Dobbs, et al

Giant molecular clouds (GMCs) are the primary reservoirs of cold, SF molecular gas in the MW and similar galaxies, and thus any understanding of SF must encompass a model for GMC formation, evolution, and destruction.  These models are necessarily constrained by measurements of interstellar molecular and atomic gas, and the emergent, newborn stars.  Both observations and theory have undergone great advances in recent years, the latter driven largely by improved numerical simulations, and the former by the advent of large-scale surveys with new telescopes and instruments.  Offer a thorough review of the current state of the field.

1312.3233
A comparison between semi-analytic model predictions for the CANDELS survey
Lu, Wechsler, … et al

Compare the predictions of three independently developed SAM models that are being used to aid in the interpretation of results from the CANDELS survey.  These models are each applied to the same set of halo merger trees extracted from the "Bolshoi" simulation and are carefully tuned to match the local galaxy stellar mass function using Bayesian Inference coupled with MCMC or by hand.  The comparisons reveal that in spite of the significantly different parameterizations for SF and feedback processes, the three models yield qualitatively similar predictions for the assembly histories of galaxy stellar mass and SF over cosmic time.  Show that the SAMs generally require strong outflows to suppress SF in low-mass halos to match the present day stellar mass function.  However, all of the models considered produce predictions for the SFRs and metallicities of low-mass galaxies that are inconsistent with existing data and diverge between the models.  Suggest that large differences in the metallicity relations and small differences in the stellar mass assembly histories of model galaxies stem from different assumptions for the outflow mass-loading factor.  Importantly, while more accurate observational measurements for stellar mass, SFR and metallicity of galaxies at 1<z<5 will discriminate between models, the discrepancies between the models and existing data of these observables have already revealed challenging problems in understanding SF and its feedback in galaxy formation.  The three sets of models are being used to construct catalogs of mock galaxies on light cones that have the same geometry as the CANDELS survey, which should be particularly useful for quantifying the biases and uncertainties on measurements and inferences from the real observations.

1312.3241
Trigonometric parallaxes for 1,507 nearby mid-to-late M-dwarfs
Dittmann et al

MEarth survey: search for small rocky planets around the smallest, nearest stars to the sun as identified by high proper motion with red colors.  Average precision of 5 milliarcseconds; combined with 2MASS photometry, allow absolute K_s magnitude for each star, allowing better estimates of the stellar parameters than those obtained with photometric estimates alone and to better prioritize the targets chosen to monitor at high cadence for planetary transits.  The MEarth sample is mostly complete out to a distance of 25 parsecs for stars of type M5.5V and earlier, and mostly complete for later type stars out to 20 parsecs.  Find 8 stars that are within 10 parsecs of the Sun for which there did not exist a published trigonometric parallax distance estimate.  Release a catalog of the trigonometric parallax measurements for 1,507 mid-to-late M-dwarfs, as well as new estimates of their masses and radii.

1312.3313
Planck data reconsidered
Spergel, Flauger, Hlozek

The tension between the best fit parameters derived by the Planck team and a number of other astronomical measurements suggests either systematics in the astronomical measurements, systematics in the Planck data, the need for new physics, or a combination thereof.  Reanalyze the Planck data and find that the 217 GHz x 217 GHz detector set spectrum used in the Planck analysis is responsible for some of this tension.  use a map-based FG cleaning procedure, relying on a combination of 353 GHz and 545 GHz maps to reduce residual FGs in the intermediate frequency maps used for cosmological inference.  For the baseline data analysis, which uses 47% of the sky and makes use of both 353 and 545 GHz data for FG cleaning, find the LCDM cosmo parameters Omega_c h^2 = 0.1169 pm 0.0025, n_s=0.9671 pm 0.0069, H0=68.0 pm 1.1 km/s/Mpc, Omega_b h^2 = 0.02197 pm 0.00027, ln 10^10 A_s = 3.080 pm 0.025, and tau = 0.089pm0.013.  While in broad agreement with the results reported by the Planck team, these revised parameters imply a universe with a lower matter density of Omega_M=0.302 pm 0.015, and parameter values generally more consistent with pre-Planck CMB analyses and astronomical observations.  Compare cleaning procedure with the FG modeling used by the Planck team and find good agreement.  The difference in parameters between analysis and that of the Planck team is mostly due to the use of cross-spectra from the publicly available survey maps instead of their use of the detector set cross-spectra which include pixels only observed in one of the surveys.  Show evidence suggesting residual systematics in the detector set spectra used in the Planck likelihood code, which is substantially reduced for this spectra.

1312.3320
A Herschel [C II] Galactic plane survey II: CO-dark H2 in clouds
Langer et al

Find that a significant fraction of the warm molecular ISM gas is invisible in HI and CO, but is detected in [CII].  The fraction of CO-dark H2 is greatest in the diffuse clouds and decreases with increasing total column density, and is lowest in the massive clouds.

1312.3323
The structure of Exoplanets
Spiegel, Fortney, Sotin

Review the diverse range of interior structures that are known to, and speculated to, exist in exoplanetary systems --- from mostly degenerate objects that are more than 10 times as massive a Jupiter, to intermediate-mass Neptune-lie objects with large cores and moderate hydrogen/helium envelopes, to rocky objects with roughly the mass of the Earth.

1312.3328
Identifying clustering at high redshift through actively star-forming galaxies
Davies et al

Identifying galaxy clustering at high z (i.e., z>1) is essential to our understanding of the current cosmological model.  However, at increasing z, clusters evolve considerably in SF activity and so are less likely to be identified using the widely-used red sequence method.  Assess the viability of instead identifying high z clustering [or clusters?] using actively SF galaxies (SMGs associated with over-densityes of BzKs/LBGs).  Perform both a 2- and 3-D clustering analysis to determine whether or not true (3D) clustering can be identified where only 2d data are available.  As expected, find that 2d clustering signals are weak at best and inferred results are method dependent.  In the 3d analysis, identify 12 SMGs associated with an over-density of galaxies coincident both spatially and in redshift - just 8% of SMGs with known redshifts in the sample.  Where an SMG in the target fields lacks a known redshift, their sightline is no more likely to display clustering than blank sky fields; prior redshift information for the SMG is required to identify a true cluster signal. Find that the strength of clustering in the volume around typical SMGs, while identifiable, is not exceptional.  However, a small number of highly clustered regions are identified, all associated with an SMG.  The most notable of these potentially contains an SMG, a QSO and 36 SF galaxies (a >20 sigma over-density) all at z~1.8.  This region is highly likely to represent an actively SF cluster and illustrates the success of using SF galaxies to select sites of early clustering Given the increasing number of deep fields with large volumes of spectroscopy, or high quality and reliable photometric redshifts, this opens a new avenue for cluster identification in the young Universe.

1312.3329
The SCUBA-2 cosmology legacy survey: Ultraluminous star-forming galaxies in a a z=1.6 cluster
Smail et al

Analyze new SCUBA-2 sub millimeter and archival SPIRE FIR imaging of a z=1.62 cluster, which lies in the UKIDSS/UDS field of the SCUBA-2 cosmology legacy survey.  Combining these tracers of obscured SF activity with the extensive photometric and spectroscopic information available for this field, identify 31 FIR/submillimeter-detected probably cluster members with bolometric luminosities >1e12 L_sun and show that by virtue of their dust content and activity, these represent some of the reddest and brightest galaxies in this structure.  Exploit Cycle-1 ALMA sub millimeter continuum imaging which covers one of these sources to confirm the identification of a SCUBA-2-detected ultra luminous star-forming galaxy in this structure.  Integrating the total SF activity in the central region of the structure, estimate that it is an order of magnitude higher (in a mass-normalised sense) than clusters at z~0.5-1.  However, also find that the most active cluster members do not reside in the densest regions of the structure, which instead host a population of passive and massive, red galaxies.  Suggest that while the passive and active populations have comparable NIR luminosities at z=1.6, M(H)~-23, the subsequent stronger fading of the more active galaxies me ands that they will evolve into passive systems at the preset-day which are less luminous than the descendants of those galaxies which were already passive at z~1.6 (M(H)~-20.5 and M(H)~-21.5 respectively at z~0).  Conclude that the massive galaxy population in the dense cores of present-day clusters were already in place at z=1.6 and that in this cluster, continuing infall of less extreme, but still ultra luminous, SF galaxies onto a pre-existing structure is seen.

1312.3336
The dependency of AGN infrared color-selection on source luminosity and obscuration: an observational perspective in CDFS and COSMOS
Messias et al

Confirm that AGN IR-selection is genuinely biased toward unobscured AGN, but only at intermediate luminosities.  At the highest luminosities, where AGN IR-selection is more efficient, there is no obscuration bias.  Showa that type-1 AGNs are intrinsically more luminous than type-2 AGN only at z<~1.6 [does that make sense, if the difference between types 1 and 2 are the dust obscuration angles?] thus resulting in more type-1 AGN being selected the shallower the IR survey is.

1312.3337
Increased insolation threshold for runaway greenhouse processes on Earth like planets
Leconte et al

Because the solar luminosity increases over geological timescales, Earth climate is expected to warm, increasing water evaporation which, in turn, enhances the atmospheric greenhouse effect.  Above a certain critical insolation, this destabilizing greenhouse feedback can "runaway" until all the oceans are evaporated.  Through increases in stratospheric humidity, warming may also cause oceans to escape to space before the runaway greenhouse occurs. The critical insolation [amount of solar radiation reaching a given area] thresholds for these processes, however, remain uncertain because they have so far been evaluated with unidimensional models that canon account for the dynamical and cloud feedback effects that are key stabilizing features of Earth's climate.  Use a 3d global climate model to show that the threshold for the runaway greenhouse is about 375 W/m^2, significantly higher than previously thought.  Model is specifically developed to quantify the climate response of Earth-like planets to increase insolation in hot and extremely moist atmospheres.  In contrast with previous studies, find that clouds have a destabilizing feedback on the long term warming.  However, subsident [gradual sinking of an area of land], unsaturated regions created by the Hadley circulation have a stabilizing effect that is strong enough to defer the runaway greenhouse limit to higher insolation than inferred from 1d models.  Furthermore, because of wavelength-dependent radiative effects, the stratosphere remains cold and dry enough to hamper atmospheric water escape, even at large fluxes.  This has strong implications for Venus early water history and extends the size of the habitable zone around other stars.

1312.3415
Testing local anisotropy using the method of smoothed residuals I - Methodology
Appleby, Shafieloo

Discuss method of smoothed residuals, which has recently been used to search for anisotropic signals in low-z distance measurements (SNe).  In this short note, focus on some details regarding the implementation of the method, particularly the issue of effectively detecting signals in data that are inhomogeneously distributed on the sky.  Using simulated data, argue that the original method proposed in Colin+ will not detect spurious signals due to incomplete sky coverage, and that introducing additional Gaussian weighting to the statistic can hinder its ability to detect a signal.  Issues related to the width of the Gaussian smoothing are also discussed.

1312.3442
Gas-to-dust mass ratios in local galaxies over a 2 dex metallicity range
Rémi-Ruyer et al

Analyze the behavior of the gas-to-dust ratio (G/D) of local universe galaxies over a large metallicity range.  Combine Dwarf Galaxy Survey, KINGFISH survey and a subsample from Galametz+, totaling 126 galaxies, covering a 2 dex metallicity range, with 30% of the sample with 12+log(O/H) < 8.0.  The dust masses are homogeneously determined with a semi-empirical dust model, including submm constraints.  The atomic and molecular gas masses are compiled from the literature.  Two XCO are used to estimate molecular gas masses: the Galactic XCO, and a XCO depending on the metallicity (as Z^-2).  Correlations with morphological types, stellar masses, SFRs and sSFRs are discussed.  The trend between G/D and metallicity is empirically modeled using power-laws (slope of -1 and free) and a broken power-law.  Compare the evolution of the G/D with predictions from chemical evolution models.  Find that out of the five tested galactic parameters, metallicity is the galactic property deriving the observed G/D.  The G/D versus metallicity relation cannot be represented by a power-law with a slope of -1 over the whole metallicity range.   The observed trend is steeper for metallicities lower than ~8.0.  A large scatter is observed in the G/D for a given metallicity, with a dispersion of 0.37 dex in metallicity bins of ~0.1 dex.  The broken power-law reproduces best the observed G/D and provides estimates of the G/D that are accurate to a factor of 1.6.  The good agreement of the G/D and its scatter with the three tested chemical evolution models shows that the scatter is intrinsic to galactic properties, reflecting the different SFHs, dust destruction efficiencies, dust grain size distributions and chemical compositions across the sample.

1312.3468
Exoplanetary searches with gravitational microlensing: polarization issues
Zakharov et al

There are different methods for finding exoplanets such as radial spectral shifts, astrometrical measurements, transits, timing etc.  Gravitational microlensing (including pixel-lensing) is among the most promising techniques with the potential of detecting Earth-like planets at distances about a few astronomical units from their host star or near the so-called snow line with a temperature in the range 0-100 C on a solid surface of an exoplanet.  Emphasize the importance of polarization measurements which can help to resolve degeneracies in theoretical models.  In particular, the polarization angle could give additional information about the relative position of the lens with respect to the source.

Day 567

Friday.

1312.2458
Magnification of photometric LRGs by foreground LRGs and clusters in SDSS
Bauer, Gaztañaga, Martí, Miquel

Measure the mass profiles of spectroscopic LRGs and galaxy clusters by measuring WL magnification of photometric LRGs in their BG.  Measure the change in detected galaxy counts as well as the increased average galaxy flux behind the lenses.  In addition, measure the average change in source color due to extinction by dust in the lenses.  By simultaneously fitting these 3 probes, constrain the mass profiles and dust-to-mass ratios of the lenses in six bins of lens richness. For each richness bin, fit an NFW halo mass, BCG mass, second halo term, and dust-to-mass ratio, and marginalize over uncertainties in the lensing sensitivities alpha_{c,m}.  Measure a mass-richness relation consistent with previous measurements of the catalogs, and limits on the dust-to-mass ratio in the lenses in agreement with expectations.  Explore the effects of including the (low S/N) flux magnification and reddening measurements in the analysis compared to using only the counts magnification data; the additional probes significantly improve the agreement between the measured mass-richness relation and previous results.
1312.2462
Constraints on the CMB temperature evolution using multi-band measurements of the Sunyaev Zel'dovich effect with the South Pole Telescope
Saro et al

The adiabatic evolution of the temperature of the CMB is a key prediction of standard cosmology.  Study deviations from the expected adiabatic evolution of the CMB temperature from T(z) = T_0(1+z)^(1-alpha) using measurements of the spectrum of the SZ effect with SPT.  Present a method for using the ratio of the SZ signal at 95 and 150 GHz in the SPT data to constrain the temperature of the CMB.  Demonstrate that this approach provides unbiased results using mock observations of clusters from a new set of hydro-sims.  Apply this method to a sample of 158 SPT-selected clusters, spanning 0.05<z<1.35, and measure alpha=0.017pm0.03, consistent with the standard model prediction of alpha=0.  In combination with other published results, constrain alpha=0.011pm0.016, an improvement of ~20% over published constraints.  This measurement also provides a strong constraint on the effective equation of state in models of decaying DE w+eff = -0.987pm0.016.

1312.2464
Stellar spectral signatures in high-redshift galaxies
Leitherer

Stellar emission and absorption lines are routinely observed in galaxies at z up to 5 with spectrographs on 8-10m class telescopes.  While the overall spectra are well understood and have been successfully modeled using empirical and theoretical libraries, some challenges remain.  Three issue are discussed: determining abundances using stellar and interstellar spectral lines, understanding the origin of the strong, stellar He II 1640 line, and gauging the influence of stellar Lyman-alpha on the combined stellar+nebular profile.  All three issues can be tackled with recently created theoretical stellar libraries for hot stars which take into account the radiation-hydrodynamics of stellar winds.

1312.2513
Strong neutrino cooling by cycles of electron capture and $/beta^-$ decay in neutron star crusts
Schatz et al

* Urca process: In astroparticle physics, an Urca process is a reaction which emits a neutrino and which is assumed to take part in cooling processes in NS and WDs.  Process was first discussed by Gamow and Schoenberg in a casino named Cassino de Urca.

The temperature in the crust of an accreting NS, which comprises its outermost kilometer, is set by heating from nuclear reactions at large densities, neutrino cooling, and heat transport from the interior.  The heated crust has been thought to affect observable phenomena at shallower depths, such as thermonuclear bursts in the accreted envelope.  Here, report that cycles of electron capture and its inverse, beta- decay, involving neutron-rich nuclei at a typical depth of about 150m, cool the outer NS crust by emitting neutrinos while also thermally decoupling the surface layers from the deeper crust.  This Urca mechanism has been studied in the context of WDs and SNIa, but hitherto was not considered in NS, because previous models computed the crust reactions using a zero-temperature approximation and assumed that only a single nuclear species was present at any given depth.  This thermal decoupling means that X-ray bursts and other surface phenomena are largely independent of the strength of deep crustal heating.  The unexpectedly short recurrence times, of the order of years, observed for very energetic thermonuclear super bursts are therefore not an indicator of a hot crust, but may point instead to an unknown local heating mechanism near the NS surface.

Day 566

Friday. …. Wednesday.

1312.2313
Precision astronomy with imperfect fully depleted CCDs -- an introduction and a suggested lexicon
Stubbs

Summary of challenges of making precision astronomical measurements using deeply depleted (thick) CCDs.  While thick CCDs provide definite advantages in terms of increased quantum efficiency at NIR wavelengths, and reduced fringing from atmospheric emission lines, these devices also exhibit undesirable features that pose a challenge to precision determination of the positions, fluxes, and shapes of astronomical objects, and features in astronomical spectra.  Many of the effects seen in these devices arise from lateral electoral fields within the detector, that produce charge transport anomalies that have been previously misinterpreted as quantum efficiency variations.  Performing simplistic flat-fielding introduces systematic errors in the image processing pipeline.  One measurement challenge is devising a calibration method that can distinguish genuine quantum efficiency variations from charge transport effects.  Given the scientific benefits of improving both the precision and accuracy of astronomical measurements, need to identify, characterize and overcome these various detector artifacts.  In retrospect, many of the detector features first identified in thick CCDs also afflict measurements made with more traditional CCD detectors, albeit often at a reduced level.  Provide a qualitative overview of the physical effects of the physical effects believed to be responsible for the observed device properties, and provide some perspective for the work that lies ahead.  Establishing a clear and consistent vocabulary when describing these various detector features, and make some suggestions for a standard lexicon based on discussions at the workshop.

1312.2330
A provocative summary: is there any unified model for triggering active galactic nuclei?
Taniguchi

Summary of "galaxy mergers in an evolving universe".  Conference covers 1) mergers at low z, 2) merger dynamics and numerical simulations, 3) mergers in galaxy evolution, 4) mergers and AGNs, 5) mergers at high z and submm galaxies, 6) feedback from starbursts and AGNs, 6) chemical evolution of galaxies, and 7) results from new surveys.  "Is there any unified model for triggering AGN?"  Given key observational properties of galaxies with AGNs, a possible unified model is discussed as an evolutionary model from starbursts to AGNs based on minor and major mergers between/among galaxies.

1312.2373
Magnetic fields in stars: origin and impact
Langer

Various types of B-fields occur in stars: small scale fields, large scale fields, and internal toroidal fields.  While the latter may be ubiquitous in stars due to differential rotation, small scale fields (spots) may be associated with envelope convection in all low and high mass stars.  The stable large scale fields found in only about 10% of intermediate mass and massive stars may be understood as a consequence of dynamical binary interaction, e.g., the merging of two stars in a binary.  Relate these ideas to B-fields in white dwarfs and neutron stars, and to their role in core-collapse and thermonuclear supernova explosions.

1312.2399
An HI study of NGC 3521 - a galaxy with a slow-rotating halo
Elson

The anomalous HI lags the regular HI by ~25-125 km/s; possible location of anomalous HI strongly suggest it to be distributed in a thick disc with a scale height of ~3.5 kpc, constituting a slow-rotating halo gas component (consistent with nearby galaxies), spatially coincident with the inner regions of the stellar disc where the SFR is highest.  It is most likely a galactic fountain that has deposited gas from the from the disc of the galaxy into the halo.

1312.2417
Massive star-forming host galaxies of quasars on SDSS stripe 82
Matsuoka, Strauss, Price, DiDonato

Stellar properties of 800 optically luminous, unobscured galaxies at z<0.6 analyzed.  Decompose into nucleus and host galaxy from PSF and Sersic models.  Systematic errors in measured absolute magnitudes and colors are 0.5 and 0.1 mag respectively, with simulated quasar images.  Effect of quasar light scattered by the ISM is also addressed.  The measured quasar-to-galaxy ratio in total flux decreases toward longer wavelengths, from ~8 in the u band to ~1 in the i and z bands.  Find that SDSS quasars are hosted exclusively by massive galaxies (M*>1e10 Msun), which is consistent with previous results for less luminous narrow-line (obscured) AGNs.  The quasar hosts are very blue and almost absent on the red sequence, showing stark contrast to the color-magnitude distribution of normal galaxies.  The fact that more powerful AGNs reside in galaxies with higher SF efficiency may indicate that negative AGN feedback, if it exists, is not concurrent with the most luminous phase of AGNs.  Also find positive correlation between the mass of SMBHs, and host stellar mass, but the M_BH-M* relation is offset toward large M_BH or small M* compared to the local relation.  While this could indicate that SMBHs grow earlier than do their host galaxies, such an argument is not conclusive, as the effect may be dominated by observational biases.

Day 565

Thursday. 

1312.2199
Evidence for cosmic neutrino background from CMB circular polarization
Mohammadi

The primordial anisotropies of the CMB are linearly polarized via Compton-scattering.  On the other hand, a primordial degree of circular polarization the CMB is not observationally excluded.  In this work, discuss the generation of the circular polarization of CMB via their scattering on the cosmic neutrino BG since the epoch of recombination.  Show that photon-neutrino interaction can transform plane polarization into circular polarization through processes gamma+nu=> gamma+nu and the Stokes-V parameter of CMB has linear dependence on the wavelength and square dependence on the average bulk velocity of CMB and also the maximum value of C^V is estimated in range of a few Nano-Kelvin square.

1312.2215
The onset of spiral structure in the universe
Elmegreen, Elmegreen

The onset of spiral structure in galaxies appears to occur between 1.4<z<1.8 when disks have developed a cool stellar component, rotation dominates over turbulent motions in the gas, and massive clumps become less frequent.  During the transition from clumpy to spiral disks, two unusual types of spirals are found in the HUDF that are massive, clumpy and irregular like their predecessor clumpy disks, yet spiral-like or sheared like their descendants. One type is "wooly" with massive clumpy arms all over the disk and is brighter than other disk galaxies at the same redshift, while another type has irregular multiple arms with high pitch angles, SF knots and no inner symmetry like today's multiple-arm galaxies.  The common types of spirals seen locally are also present in a range around z~1, namely grand design with two symmetric arms, multiple arm with symmetry in the inner parts and several long, thin arms in the outer parts, and flocculent, with short, irregular and patchy arms that are mostly from SF.  Normal multiple arm galaxies are found only closer than z~0.6 in the UDF.  Grand design galaxies extend furthest to z~1.8, presumably because interactions can drive a two-arm spiral in a disk that would otherwise have a more irregular structure.  The difference between these types is understandable in terms of the usual stability parameters for gas and stars, and the ratio of the velocity dispersion to rotation speed.  [that's pretty cool!]

Day 564

Wednesday.

1312.2009
Spectra as windows into exoplanet atmospheres
Burrows

Planet's atmosphere necessary to understand: the planet itself, its formation, structure, evolution and habitability.  Spectra would be great, but very far for exoplanets.  Give a personal perspective on exoplanet theory and remote sensing via photometry and low-res spectroscopy.  Highlight the limitations in knowledge of compositions, thermal profiles, effects of stellar irradiation, focusing on transiting giant planets.  Recent past of exoplanet atmospheric research has been not to constrain planet properties for all time, but to train a new generation of scientists that is fast establishing a solid future foundation for a robust science of exoplanets.

1312.2013
The MICE grand challenge light cone simulation II: halo and galaxy catalogues
Crocce et al

Present end-to-end simulation from MICE-GC run.  Introduce halo and galaxy catalogues built on it, both in wide (5000 sq deg) and deep (z<1.4) light-cone in several redshift snap shots.  FoF halos resolved down to 1e11 Msun/h, allowed modeling galaxies down to faint luminosities (M_r<-18.9).  Used a new hybrid HOD and abundance matching technique for galaxy assignment.  The catalogue includes SEDs of all galaxies from which multi-band photometric galaxy surveys are modeled.  Describe a variety of applications for halo and galaxy clustering statistics.  Discuss how mass resolution effects can bias the large scale 2pt clustering amplitude of poorly resolved haloes at the <~5% level, and their 3pt correlation function.  Find a characteristic scale dependent bias of <~6% across the BAO feature for halos well above M* ~1e12 Msun/h and for LRG like galaxies.  For haloes well below M* the scale dependence at 100 Mpc/h is <~2%.  Lastly discuss the validity of the large-scale Kaiser limit across redshift and departures from it towards NL scales, in particular due to the motion of satellite galaxies.  Make the current version of light-cone halo and galaxy catalogue (MICECATv1.0) publicly available on http://cosmohub.pic.es, to help develop and exploit the new generation of astronomical surveys.

1312.2025
Using dimers to measure biosignatures and atmospheric pressure for terrestrial exoplanets
Misra, Meadows, Claire, Crisp

Present new method to probe atmospheric pressure on Earthlike planets using (O2-O2) dimers in the near-IR.  Show that dimer features possibly the most readily detectable biosignatures for Earthlike atmospheres, may even be more detectable in transit transmission with JWST.  Absorption by dimers changes more rapidly with pressure and density than that of monomers, and can therefore provide additional information about atmospheric pressures.  By comparing the absorption strengths of rotational and vibrational features to the absorption strengths of dimer features, show that in some cases it may be possible to estimate the pressure at the reflecting surface of a planet.  This method is demonstrated using the O2 A band and the 1.06 um dimer feature, either in transmission or reflected spectra.  It works best for planets around M dwarfs with atmospheric pressures between 0.1 and 10 bars, and for O2 volume mixing ratios above 50% of Earth's present day level.  Furthermore, unlike observations of Rayleigh scattering, this method can be used at wavelengths longer than 0.6 um, and is therefore potentially applicable, although challenging, to near-term planet characterization mission such as JWST.  Performed detectability studies for JWST transit transmission spectroscopy and find the the 1.06 um and 1.27 um dimer features could be detectable (SNR>3) for an Earth-analog orbiting an M5V star at distance of 5 pc.  The detection of these features could provide a constraint on the atmospheric pressure of an exoplanet, and serve as biosignatures for oxygenic photosynthesis.  Calculated the required SNRs to detect and characterize O2 monomer and dimer features in reflected spectra and find that SNRs greater than 10 at a spectral resolving power of R=100 would be required.

1312.2101
PkANN - II. A non-linear matter power spectrum interpolator developed using artificial neural networks
Agarwal, Abdalla, Feldman, Lahav, Thomas

Introduce PkANN, SW package for interpolating the NL matter PS, constructed using ANNs.  Previously, using Halofit to calculate matter power spectrum, demonstrated that ANNs can make extremely quick and accurate predictions of the PS.  Using a suite of 6380 N-body sims spanning 580 cosmologies, train ANNs to predict the PS over the cosmological parameter space spanning 3sigma CL around the concordance cosmology.  Present with a set of cosmological parameters (Omh2, Obh2, ns, w, sigma8, Sum m_nu and redshift z), the trained ANN interpolates the PS for z<~2 at sub% accuracy for modes up to k<0.8 h/Mpc.  PkANN is after than computationally expensive N-body sims, yet provides a worst-case error <1% fit to the NL matter PS deduced through N-body sims.  The overall precision of PkANN is set by the accuracy of the N-body sims, at 5% level for cosmological models with Sum m_nu<0.5 eV for all redshifts z<=2.  For models with Sum m_nu>0.5 eV, predictions are expected to be at 5(10)% level for redshifts z>1 (z<=1).  The PkANN interpolator publicly available at http://zuserver2.star.ucl.ac.uk/~fba/PkANN.

Day 563

Monday.

1312.1707
The MICE Grand Challenge Lightcone Simulation I: Dark matter clustering
Fosalba et al

MICE-GC: 7e10 DM partices in (3 Gpc/h)^3 comoving volume N-body simulation; 5 orders of magnitude in dynamic range.  Allows an accurate modeling of the growth of structure in the universe from the linear through the highly NL regime of gravitational clustering.  Validate the DM simulation outputs using 3D and 2D clustering statistics, and discuss mass-resolution effects in the NL regime by comparing to previous simulations and the latest numerical fits.  Show that the MICE-GC run allows for a measurement of the BAO feature with percent level accuracy and compare it to state-of-the-art theoretical models.  Also use sub-arcmin resolution pixelized 2D maps of the DM counts in the light cone to make tomographic analyses in real and redshift space.  Analysis shows the simulation reproduces the Kaiser effect on large scales, but find a significant suppression of power on NL scales relative to the real space clustering [due to z-space distortion or what?].  Complete validation by presenting an analysis of the 3pt correlation function in this and previous MICE simulations, finding further evidence for mass-resolution effects.  This is the first of a series of 3 papers in which the MICE-GC end-to-end simulation is presented, along with a wide (5000 sq deg) and deep (z<1.4) mock galaxy catalog constructed using a hybrid HOD and Halo Abundance Matching approach.  Accompanying these papers, make a first public release of MICE-GC light cone galaxy mock (MICECAT v1.0) through http://cosmohub.pic.es, to help develop and exploit new generation of astronomical surveys.

1312.1715
The Keplerian orbit of G2
Meyer et al

G2: the gaseous red emission-line object that is on a very eccentric orbit around the Galaxy's central BH, and predicted to come within 2400 Rs in early 2014.  Use laser guide star AO system on Keck I and II telescopes to obtain 3 epochs of spectroscopy and imaging at highest spatial resolution in near-IR.  Updated orbital solution from radial velocities + Br-Gamma line astrometry is consistent with earlier estimates.  Even ~6 months before pericenter passage there is no perceptible deviation from a Keplerian orbit.  Show that a proposed "tail" of G2 is likely not associated with it, but is rather an independent gas structure.  Also show that G2 does not seem to be unique, since several red emission-line objects can be found n the central arc second.  Taken together, seems more likely that G2 is ultimately stellar in nature, although there is clearly gas associated with it.

1312.1729
The flattening of the concentration-mass relation towards low halo masses and its implications for the annihilation signal boost
Sanchez-Conde, Prada

In standard CDM, there exists a tight connection between the properties of DM haloes, and their formation epochs.  Such relation can be expressed in terms of a single key parameter, namely the halo concentration.  In this work, examine the concentration-mass relation c(M), at present time over more than 20 orders of magnitude in halo mass (from Earth mass micro halos up to galaxy clusters).  Use the c(M) model proposed by Prada+ (2012) to test its predictions against results from N-body cosmo sims.  Despite little knowledge of halo concentrations below 1e8 Msun in simulations, the model works remarkable well; it is compatible with all the available data down to 1e6 Msun within 1 sigma.  Both simulation results and model show a clear flattening of the halo concentration-mass relation towards smaller masses that excludes the commonly used power-law c(M) models, and stands as a natural prediction for the CDM model.  Provide a parameterization for the c(M) relation that works accurately for all halo masses.  The flattening of the halo concentrations at low halo masses has decisive consequences e.g. for gamma-ray DM searches, as it implies more modest enhancements of the DM annihilation flux due to DM substructure than usually adopted in the literature, i.e. of ~1000 for galaxy clusters, and ~200 for MW-sized halos (e.g., Springel+2008, Gao+2012).  These values relied on such power-law c(M) extrapolations and those are clearly rejected.  Obtain much lower boosts, i.e., ~35 for galaxy clusters and ~15 for galaxies like MW.  These figures may have a critical impact on current and up-coming gamma-ray search strategies.  Finally provide a parameterization of the boost that can be safely used for dwarf- to cluster-size halos.

1312.1736
The Solar Neighborhood XXXII. The Hydrogen burning limit
Dieterich et al

Construct a HR diagram for the stellar/substellar boundary based on a sample of 63 objects ranging in spectral type from M6V to L4.  Report newly observed VRI photometry for all 63 objects and new trigonometric parallaxes for 37 objects.  The remaining 26 objects have trigonometric parallaxes from the literature.  Combine optical photometry and trigonometric parallaxes with 2MASS and WISE photometry and employ a novel SED fitting algorithm to determine effective temperatures, bolometric luminosities, and radii.  Uncertainties range from ~20K to ~150 K in temperature, ~0.01 to ~0.06 in log(L/Ls) and 3% to 10% in radius.  Check methodology by comparing calculated radii to radii directly measured via long baseline optical interferometry [did it work out OK?].  Find deviance for the local minimum in the radius-temperature and radius-luminosity trends that signals the end of the stellar MS and the start of the brown dwarf sequence at T~2075K, log(L/Ls)~-3.9, and (R/Rs)~0.086.  The existence of this local minimum is predicted by evolutionary models, but at temperatures ~400K cooler.  The minimum radius happens near the locus of 2MASS J0523-1403, an L2.5 dwarf with V-K=9.42.    Make qualitative arguments as to why the effects of the recent revision in solar abundances accounts for the discrepancy between the findings here and the evolutionary models.  Also report new color-absolute mag relations for optical and IR colors useful for estimating photometric distances.  Study the optical variability of all 63 targets and find an overall variability fraction of 36pm8% at a threshold of 15 milli-mags in the I band, in agreement with previous studies.  [tiny variability!  where does it come from?]

1312.1836
Discovery of the first B[e] supergiants in M 31
Kraus et al

B[e] supergiants (B[e]SGs) are transitional objects in the post-MS evolution of massive stars.  The small number of B[e]SGs known so far in the Galaxy and the Magellanic Clouds indicates that this evolutionary phase is short.  Nevertheless, the strong aspherical mass loss occurring during this phase, which leads to the formation of rings or disk-like structures, and the similarity to possible progenitors of SN1987A emphasize the importance of B[e]SGs for the dynamics of the ISM as well as stellar and galactic chemical evolution.  The number of objects and their mass loss behavior at different metallicities are essential ingredients for accurate predictions from stellar and galactic evolution calculations.  However, B[e]SGs are not easily identified, as they share many characteristics with luminous blue variables (LBVs) in their quiescent (hot) phase.  Present medium-resolution near-IR K-band spectra for four stars in M 31, which have been assigned a hot LBV (candidate) status.  Applying diagnostics that were recently developed to distinguish B[e]SGs from hot LBVs, classify two of the objects as bonafide LBVs; one of them currently in outburst.  In addition, firmly classify two stars as the first B[e]SGs in M 31 based on strong CO band emission detected in their spectra, and IR colors typical for this class of stars.

1312.1846
Multi-frequencey constraints on the non-thermal pressure in galaxy clusters
Colafrancesco et al

The origin of radio halos in galaxies clusters is still unknown and is the subject of debate both from the observational and theoretical point of view.  In particular the amount and the nature of non-thermal plasma and of the B-field energy density in clusters hosting radio halos is still unclear.  The aim of this paper is to derive an estimate of the pressure ratio X between the non-thermal and thermal plasma in radio halo clusters that have combined radio, X-ray and SZ effect observations.  From the simultaneous P-L_X and P-Y_SZ correlations [is P=plasma pressure?] for a sample of clusters observed with Planck, derive a correlation between Y_SZ and L_X that are used to derive a value for X.  This is possible since the Compton parameter Y_SZ is proportional to the total plasma pressure n the cluster (a sum of the thermal and non-thermal pressure) while the X-ray luminosity L_X is proportional only to the thermal pressure of the intracluster plasma.  Results indicate that the average (best fit) value of the pressure ratio in a self-similar cluster formation model is X=0.55 pm 0.05 in the case of an isothermal beta-model with beta=2/3 and a core radius r_c=0.3 R_500 holding on average for the cluster sample.  Also show that the theoretical prediction for the Y_SZ-L_X correlation in this model has a slope that is steeper than the best fit value for the available data.  The agreement with the data can be recovered if the pressure ratio X decreases with increasing X-ray luminosity as L_X^-0.96.  Conclude that the available data on radio halo clusters indicate a substantial amount of non-thermal pressure in cluster atmospheres whose value must decrease with increasing X-ray luminosity, or increasing cluster mass (temperature).

1312.1852
Parameterizing the local dark matter speed distribution: a detailed analysis
Kavanagh

A new parameterization of DM speed distribution f(v) proposed for use in the analysis of data from direct detection experiments.  This parameterization involves expressing the logarithm of the speed distribution as a polynomial in the speed v.  Present here a more detailed analysis of the properties of this parameterization.  Show that the method leads to statistically unbiased mass reconstructions and exact coverage of credible intervals [? verified using simulations?].  The method performs well over a wide range of DM masses, even when finite energy resolution and BGs are taken into account.  Also show how to select the appropriate number of basis functions for the parameterization.  Finally, look at how the speed distribution itself can be reconstructed, and how the method can be used to determine if the data are consistent with some test distribution.  In summary, show that this parameterization performs consistently well over a wide range of input parameters and over large numbers of statistical ensembles and can therefore reliably be used to reconstruct both the DM mass and speed distribution from direct detection data.

1312.1905
Molecules in the circumnuclear disk of the Galactic Center
Harada, et al

Within a few parsecs around the central BH Sgr A*, chemistry in the dense molecular cloud material of the circumnuclear disk (CND) can be affected by many energetic phenomena such as high UV-flux from the massive central star cluster, X-rays from Sgr A*, shock waves, and an enhanced CR flux.  Recently, spectroscopic surveys with the IRAM 30 m and the APEX 12 m telescopes of substantial parts of the 80-500 GHz frequency range were made toward selected positions in and near the CND.  These datasets contain lines from the molecules HCN, HCO+, HNC, CS, SO, SiO, CN, H2CO, HC3N, N2H+, H3O+ and others.  Conduct Large Velocity Gradient analyses to obtain column densities and total H densities, n, for each species in molecular clouds located in the SW lobe of CND.  The data for the above mentioned molecules indicate 1e5 cm^-3 < n<1e6 cm^-3, which shows that the CND is tidally unstable.  The derived chemical composition is compared with a chemical model calculated using the UCL_CHEM code that includes gas and grain reactions, and the effects of shock waves.  Models are run for varying shock velocities, CR ionization rates, and number densities.  The resulting chemical composition is fitted best to an extremely high value of CR ionization rage zeta~1e-14 s^-1, 3 orders of magnitude higher than the values in regular Galactic molecular clouds, if the pre-shock density is n=1e5 cm^-3.



1312.1916
All weather calibration of wide field optical and NIR surveys
Burke et al

Ground-based large-area surveys (e.g., DES, Pan-STARRS, and LSST) require calibration of broadband photometry that is stable in time and uniform over the sky to precisions of a per cent or better.  This performance will need to be achieved with data taken over the course of many years, and often in less than ideal conditions.  This paper describes a strategy to achieve precise internal calibration of imaging survey data taken in less than photometric conditions, and reports results of an observational study of the techniques needed to implement this strategy.  Find that images of celestial fields used in this case study with stellar densities of order one per arcmin-squared and taken through cloudless skies can be calibrated with relative precision of 0.5% (reproducibility).  Report measurements of spatial structure functions of cloud absorption observed over a range of atmospheric conditions, and find it possible to achieve photometric measurements that are reproducible to 1% in images that were taken through cloud layers that transmit as little as 25% of the incident optical flux (1.5 mag of extinction).  Find, however, that photometric precision below 1% is impeded by the thinnest detectable cloud layers.  Comment on implications of these results for the observing strategies of future surveys.  [what exactly is the strategy anyway?]

1312.1929
Simple expressions for second order density perturbations in standard cosmology
Uggla, Wainwright

Present 4 simple expressions for the relativistic first and second order fractional density perturbations for LCDM cosmologies in different gauges: Poisson, uniform curvature, total matter and synchronous gauges.  Use of a canonical set of quadratic differential expressions involving an arbitrary spatial function (comoving curvature perturbation) to describe the spatial dependence, which enables unifying, simplifying and extending previous seemingly disparate results.  The simple structure of the expressions makes the evolution of the density perturbations completely transparent and clearly displays the effect of the cosmological constant on the dynamics, namely that it stabilizes the perturbations.  Expect that the results will be useful in applications, e.g. studying the effects of primordial non-Gaussianity on the large scale structure of the universe.

1312.1947
Thermal escape from extrasolar giant planets
Koskinen et al

There are two distinct regimes f thermal escape from EGPs, and the transition between these regimes is relatively sharp.

1312.2002
Similarities and distinctions in cosmic-ray modulation during different phases of solar and magnetic activity cycles
Aslam, Badruddin

Study the solar-activity and solar-polarity dependence of galactic CR intensity (CRI) on the solar and heliospheric parameters playing a significant role in solar modulation.  … The relative CRI-response to changes in various parameters (solar activity by sunspot number (SSN), interplanetary plasma/field parameters, solar-wind velocity V, magnetic field B, tilt of the heliospheric current sheet (Lambda), neutron monitors [counts]).  Regression analysis to calculate and compare the CRI-response to changes in different solar/interplanetary parameters during (i) different phases of solar activity and (ii) similar activity phases but different polarity states.  Find that the CRI response is different during negative as compared to positive polarity states, not only with SSN and Lambda but also with B and V.  The relative CRI-response to changes in various parameters, in negative vs positive state, is solar-activity dependent (higher at low solar activity, and nearly equal in high solar-activity conditions).  Although results can be ascribed to preferential entry of charged particles via the equatorial/polar regions of the heliosphere as predicted by drift models, these results also suggest that we should look for any polarity-dependent response of solar wind and transport parameters in modulating CRI in the heliosphere.

1312.2006 [vote?]
Les Houches Lectures on physics beyond the standard model of cosmology
Khoury

Review various extensions of LCDM model, characterized by additional light degrees of freedom in the dark sector.  In order to reproduce the successful phenomenology of GR in the solar system, these fields must effectively decouple from matter on solar system/laboratory scales.  This is achieved through screening mechanisms, which rely on the interplay between self-interactions and coupling to matter to suppress deviations from standard gravity.  The manifestation of the new degrees of freedom depends sensitively on their environment, which in turn leads to striking experimental signatures.

Day 562

Friday.  Saturday.  Sunday, one week behind.

1312.1699
Mergers as triggers for nuclear activity: A near-IR study of the close environment of AGN in the VISTA-VIDEO survey
Karouzos, Jarvis, Bonfield

AGN triggered by major or minor galaxy mergers, or through secular processes like cooling gas accretion and/or formation of bars?  Investigate the close environment of active galaxies selected in the X-ray, the radio, and the mid-IR.  Utilize DR1 of near-IR VISTA Deep Extragalactic Observations (VIDEO) survey of XMM-LSS field.  Use 2 measures of environment density: counts within a given aperture and a finite redshift slice (pseudo-3D density) and closet neighbor density measures Sigma_2 and Sigma_5.  Select both AGN and control samples, matching them in redshift and apparent Ks-band magnitude.  Find that AGN are found in a range of environments, with a subset of the AGN samples residing in over-dense environments.  Seyfert-like X-ray AGN and flat-spectrum radio-AGN are found to inhabit significantly over-dense environments compared to their control sample.  The relation between over-densities and AGN luminosity does not however reveal any positive correlation.  

1312.1700
The pressure of the star forming ISM in cosmological simulations
Munshi, et al

Examine the pressure of SF ISM of MW-sized disk galaxies using fully cosmological SPH+N-body, high resolution simulations.  These simulations include explicit treatment of metal-line cooling in addition to dust and self-sheilding, H2 based SF.  The 4 simulated haloes have masses ranging from a few times 1e10 to nearly 1e12 Msun.  Using a kinematic decomposition of these galaxies into present-day bulge and disk components, find that the typical pressure of the SF ISM in the present-day bulge is higher than that in the present-day disk by an order of magnitude [because SF has ceased in the bulge?].  Also find that pressure of the SF ISM at high z is on average higher than ISM pressures at low z [more SF at higher z, usually z~2-3; the universe should have 3-4x higher density around here!].  This explains why the bulge forms at higher pressures: the disk assembles at lower redshift, when the ISM is lower pressure and the bulge forms at high z, when the ISM is at higher pressure.  If ISM pressure and IMF variation are tied together as suggested in studies like Conroy 2012, these results could indicate a time-dependent IMF in MW-like systems, as well as a different IMF in the bulge and the disk.