Day 361

Sunday.

1212.4834
The merger rates and sizes of galaxies across the peak epoch of star formation from the HiZELS survey
Stott, et al

HiZELS Narrow-band H-alpha survey, combined with CANDELS, UKIDSS and WIRDS NIR imaging, to invesitgate the morphologies, merger rates and sizes of a sample of H-alpha emitting galaxies in the 0.40<z<2.23, an epoch encompassing the rise to the peak of the SFR density.  Merger rates are estimated from space- and ground-based imaging using the M20 coefficient [what's that?].  To account for the increase in the specific SFR (sSFR) of the SF 'main-sequence' with z, normalize the SFR of galaxies at each epoch to the typical value derived from the H-alpha LF.  Once this trend in sSFR is removed, see no evidence for an increase in the number density of SF galaxies or merger rate with redshift.  Conclude that neither is the main driver of the enhanced SFR density at z=1-2, with secular processes such as instabilities within efficiently fueled, gas-rich discs or multiple minor mergers the most likely alternatives.  However, find that 40-50% of starburst galaxies, those with enhanced specific SF at their epoch, are major mergers and this fraction is z independent.  Finally, find that the typical size of a SF galaxy of a given mass does not evolve across the redshift range considered, suggesting a universal size-mass relation.  Taken in combination, these results indicate a SF galaxy population that is statistically similar in physical size, merger rate and mass over the 6 Gyr covered in this study, despite the increase in typical sSFR.

1212.4835
Probing high-redshift galaxy formation at the highest luminosities: new insights from DEIMOS spectroscopy
Lee, Dey, Cooper, Reddy, Jannuzi

Most UV-luinous SF galaxies at 3.2,z<4.6; sample contains L*<L<7L*, largest sample to date at these z.  Clean selection of photometric candidates validated.  Fraction of Lya emitters increases with decreasing UV luminosity.  Find strong evidence of large-scale outflows, transporting the neutral/ionized gas in the ISM away from the galaxy.  Galaxies exhibiting both interstellar absorption and Lya emission lines show a significant velocity offset between the 2 features (200-1140 km/s).  Find tentative evidence that this measure of the outflow velocity increases with UV luminosity and/or stellar mass.  The luminosity- and mass-dependent outflow strengths suggest that the efficiency of feedback and enrichment of the surrounding medium depend on these parameters.  Present composite spectra of the absorption-line-only and Lya-emitting subsets of the UV luminous galaxies at z~3.7.  The composite spectra are similar to those of lower-z and lower-luminosity LBG samples, but with some subtle differences.  Analysis of the composite spectra suggest that the UV luminous LBGs at z~3.7 may have a higher covering fraction of absorbing gas, and may be older than their lower-z and lower-luminosity counterparts.  In addition, 5 galaxies discover that belong to a massive over density at z=3.78.  2 galaxies each show 2 distinct sets of interstellar absorption features.  The latter may be a sign of a final stage of major merger, or clumpy disk formation.  Their presence implies that frequency of such sources among the luminous z~3.7 LBGs may be an order of magnitude higher than in lower redshift and lower luminosity samples.

1212.4844
The cosmic MeV neutrino background as a laboratory for black hole formation
Yuksel, Kistler

Calculations of the cosmic rate of corse collapses, and the associated neutrino flux, commonly assume that a fixed fraction of massive stars collapse to black holes.  Argue that recent results suggest that this fraction instead increases with z.  With relatively more stars vanishing as "unnovae" in the distant universe, the detectability of the cosmic MeV neutrino background is improved due to their hotter neutrino spectrum, and expectations for supernova surveys are reduced.  We conclude that neutrino detectors, after the flux from normal SNe is isolated via either improved modeling or the next Galactic SN, can probe the conditions and history of BH formation.  

1212.4848
The fundamental metallicity relation reduces type Ia SN Hubble residuals more than host mass alone
Hayden, Gupta, Garnavich, Mannucci, Nichol, Sako

* FMR: mass-metllicity-SFR relation.

SNIa Hubble residuals have been shown to correlate with host galaxy mass, imposing a major obstacle for their use in measuring DE properties.  Here, calibrate the fundamental metallicity relation (FMR) of Mannucci+ (2010) for host mass and SFR measured from broad-band colors alone.  Apply the FMR to the large number of hosts from the SSS-II sample of GUpta+ 2011 and find that the scatter in the Hubble residuals is significantly reduced when compared with using only stellar mass (or the mass-metallicity relation) as a fit parameter.  Calibration of the FMR is restricted to only SF galaxies and in the Hubble residual calculation include only hosts with log(SFR)>-2.  Results strongly suggest that metallicity is the underlying source of the correlation between Hubble residuals and host galaxy mass.  Since the FMR is nearly constant between z=2 and the present, use of the FMR along with light curve width and color should provide a robust distance measurement method that minimizes systematic errors.

1212.4905
Calibrating [OII] star-formation rates at z>1 from dual H\alpha-[OII] imaging from HiZELS
Hayashi, Sorbal, Best, Smail, Kodama

Investigate the relationship between H\alpha\ and [OII](\lambda 3727) emission in faint SF galaxies at z=1.47 with dust uncorrected SFRs sown to 1.4Msun/yr, using data in 2 narrow-bands.  ... Important to take into account that the relations for the dust correction which are derived using H\alpha\ emitter samples, and frequently used in many studies of high-z galaxies, may overestimate the intrinsic SFRs of [OII]-selected galaxies, and that surveys of [OII] emission galaxies are likely to miss dusty populations.

1212.5018
A novel approach in the WIMP quest: cross-correlation of gamma-ray anisotropies and cosmic shear
Camera, Fornasa, Fornengo, Regis

DM structures are responsible for bending of light, and those same objects can emit gamma-rays, either because they host astrophysical sources (AGN or SF galaxies) or directly by DM annihilations (or decays).  Such gamma-rays should therefore exhibit strong correlation with the cosmic shear signal.  In this Letter, we compute the cross-correlation angular PS of cosmic shear and gamma-rays produced by the annihilation/decay of WIMP DM, as well as from astrophysical sources.  Show that this observable provides novel information on the composition of the EGB (extra-galactic gamma-ray BG), since the amplitude and shape of the cross-correlation signal strongly depends on which class of source is responsible for the gamma-ray emission.  If the DM contribution to the EGB is significant (at least in a definite energy range), although compatible with current observational bounds, its strong correlation with the cosmic shear makes such signal potentially detectable by combining Fermi-LAT data with forthcoming galaxy surveys, like DES and Euclid.  At the same time, the same signal would demonstrate that the WL observables are indeed due to particle DM matter, and not to possible modifications of GR.

1212.5076
Measuring the dark matter halo mass of X-ray AGN at z~1 using photometric redshifts
Mountrichas, .. Finoguenov, ... Coil, ... Newman et al

Infer the bias and DM halo mass of moderate luminosity X-ray AGN at z~1 via their X-correlation function with galaxies.  In contrast to standard cross-correlation function estimators, present a method that requires spectroscopy only for the AGN and uses photometric redshift probability distribution functions for galaxies to determine the projected real-space AGN/galaxy cross-correlation function.  The estimated DM halo mass of X-ray AGN in the combined AEGIS, COSMOS and ECDFS fields is ~13 Msun/h, in agreement with previous studies at similar redshift and luminosity ranges.  Removing from the sample the 5% of the AGN associated with x-ray selected groups results in a reduction by about 0.5 dex in the inferred AGN DM halo mass.  The distribution of AGN in DM halo mass is therefore skewed and the bulk of the population lives in moderate mass haloes.  This result favors cold gas accretion as the main channel of SMBH growth for most X-ray AGN.

1212.5077
Helioseismology: a fantastic tool to probe the interior of the Sun
Di Mauro

The study of global solar oscillations has proved to be an extremely powerful tool for the investigation of the internal structure and dynamics of the Sun.  Studies of time changes in frequency observations of solar oscillations from helioseismology experiments on Earth and in space have shown, for example, that the Sun's shape varies over solar cycle timescales.  In particular, far-reaching inferences about the Sun have been obtained by applying inversion techniques to observations of frequencies of oscillations.  The results, so far, have shown that the solar structure is remarkably close to the predictions of the standard solar model and,  recently, that the near-surface region can be probed with sufficiently high spatial resolution as to allow investigations of the equation of state and of the solar envelope He abundance.  The same helioseismic inversion methods can be applied to the rotational frequency splittings to deduce with high accuracy the internal rotation velocity of the Sun, as function of radius and latitude.  This also allows us to study some global astrophysical properties of the Sun, such as the angular momentum, the gravitational quadrupole moment and the effect of distortion induced on the surface (oblateness).  The helioseismic approach and what we have learnt from it during the last decades about the interior of the Sun are reviewed here.

1212.5092
Spherical collapse model with shear and angular momentum in dark energy cosmologies
Del Popolo, Pace, Lima

How shear and angular momentum modify typical parameters of the spherical collapse model in DE dominated universes.  Study the linear density threshold for collapse delta_c and the virial overdensity Delta_V for several DE models and its influence on the cumulative mass function.  With the introduction of shear and rotation terms, the parameters of the spherical collapse model are now mass-dependent.  The results of the paper show, as expected, that the new terms considered in the spherical collapse model oppose the collapse of perturbations on the galactic scale giving rise to higher values of the linear overdensity parameter with respect to the non-rotating case.  Find a similar effect also for the virial overdensity parameter.  For what concerns the mass function, find that its high mass tail is suppressed, while the low mass tail is slightly affected except in some cases.

1212.5159
A study on the chemical properties of blue compact dwarf galaxies
Zhao, Gao, Gu

Studies on the gaseous and chemical properties of a 53-sample blue compact dwarf galaxies (BCDs).  Correlations among O abundance, M*, M_gas, M_baryon, and f_gas are present for both E- and I-type BCDs, which are classified and show elliptical and irregular outer haloes, respectively.  These correlations of I-type BCDs show similar slopes to those of E-type ones.  However, in general, E-type BCDs are more gas-poor and metal-rich than I-type ones at a given baryonic mass.  Based on these results, suggest that E-type BCDs, at least a part of them, and I-type ones might be likely at different evolutionary phases and/or having different progenitors.  Investigation of the correlation between O abundance and gas fraction shows that BCDs appear to have not evolved as isolated systems, but to have experienced some gas flows and/or mergers.

1212.5222
A new multi-field determination of the galaxy luminosity function at z=7-9 incorporating the 2012 Hubble ultradeep field imaging
McLure, et al

Results strengthen suggestions that the evolution at z>7 is more akin to 'density evolution' than the apparent 'luminosity evolution' seen at z~5-7.  Provide the first meaningful information on the LF at z~9, explore alternative extrapolations to higher z, and consider the implications for the evolution of UV luminosity density.  Finally, provide catalogues for the 100 most robust 6.5<z<11.9 galaxies in the HUDF used in the analysis.  DIscuss results in the context of earlier work and the results of an independent analysis of the UDF12 data based on color-color selection.

1212.5225
Nine-year wilkinson microwave anisotropy probe (WMAP) observations: final maps and results
Bennett, ... Halpern, Komatsu, .. Page, Spergel, .. Dunkley, Kogut, Limon, ... Tucker, Wright et al

Findal 9 year maps and basic results from WMAP mission.  Full sky T maps, processed to reduce the asymmetry of the effective beams.  Temperature and polariation sky maps examined to separate CMB anisotropy from FG emission, and both types of signals are analyzed in detail.  Combine with finer scale CMB, BAO, and H0 constant measurements, find that BBN is well supported and no compelling evidence for a non-standard number of neutrino species (3.26pm0.35).  Model fit also implies that the age of the universe is 13.772pm0.059 Gyr, and the fit Hubble constants H0=6932pm0.8 km/s/Mpc.  Inflation is also supported: the fluctuations are adiabatic, with Gaussian random phases; the detection of a deviation of the scalar spectral index from unity reported early by WMAP now has high statistical significance (n_s = 0.9608 pm 0.0080); and the universe is close to flat/Euclidean, Omega_k = -0.0027 pm 0.0039.  Overall, the WMAP mission has resulted in a reduction of the cosmological parameter volume by a factor of 68000 for the standard 6 parameter LCDM model, based on CMB data alone.  For a model including tensors, the allowed 7-parameter volume has been reduced by a factor  117000.  Other cosmological observations are in accord with the CMB predictions, and the combined data reduces the cosmological parameter volume even further.  With no significant anomalies and an adequate goodness-of-fit, the inflationary flat LCDM model and its precise and accurate parameters rooted in WMAP data stands as the standard model of cosmology.  [What is sigma_8?]

1212.5226
Nine-year Wilkinson microwave anisotropy probe (WMAP) observations: cosmological parameter results
Hinshaw, et al

WMAP data alone are remarkable well fit by a six-parameter LCDM model.  When combined with high-l CMB anisotrpy, BAO, H0, the densities (bhp, ch2, and L) are each determined to a precision of ~1.5%.  The amplitude of the primordial spectrum is measured to within 3%, and there is now evidence for a tilt in the primordial spectrum at the 5 sigma level, confirming the first detection of tilt based on the 5 year WMAP data.  .. Compare recent PLANCK measurements of SZ effect with WMAP7, show their mutual agreement.  Analysis of the polarization pattern around temperature extrema is updated.  This confirms a fundamental prediction of the standard cosmological model and provides a striking illustration of acoustic oscillations and adiabatic initial conditions in the early universe.

Day 360

Saturday.  Send my sister off to Cameroon.

1212.4500
Systematic effects in large-scale angular power spectra of photometric quasars and implications for constraining primordial nongaussianity
Pullen, Hirata

Primordial non-Gaussianity of local type is predicted to lead to enhanced halo clustering on very large scales.  Quasars at z>2 are promising tracers for constraining non-G using this effect.  However, large-scale systematics can also mimic this signature of non-G.  In order to assess the contribution of systematic effects, cross-correlate overdensity maps of photometric quasars from SDSS DR6 in different z ranges.  Find that the maps are significantly correlated on large scales, even though the expectation is such that the angular distribution of quasars at different redshift to be uncorrelated.  THis implies that the quasar maps are contaminated with systematic errors.  Investigate the use of external templates that provide information on the spatial dependence of potential systematic errors to reduce the level of spurious clustering in the quasar data.  Find that templates associated with stellar density, the stellar color locus, airmass, and seeing are major contaminants of quasar maps, with seeing having the largest effect.  Using template projection, decrease the significance of the X-correlation measurement on the largest scales from 9 sigma to 5 sigma.  The remaining X-correlation suggests the contamination in the quasar sample too great to allow a competitive constraint on fNL by correlations internal to this sample.  The SDSS quasar catalog exhibits spurious number density fluctuations of ~2% rms, and we need a contamination level less than 1% (0.6%) in order to measure values of fNL less than 100 (10).  Properly dealing with these systematics will be paramount for future large scale structure surveys that seek to constrain non-G.

1212.4526
Cross-correlation of SDSS DR7 quasars and DR10 BOSS galaxies: the weak luminosity dependence of quasar clustering at z~0.5
Shen, McBride, White, ... Padmanabhan, Ross, ... et al

Present the 2-pt X-correlation function of 8k quasars and 349 CMASS galaxies from BOSS at <z>~0.5 (0.3<z<0.9).  The X-correlation function can be reasonably well fit bay a power-law model on projected scales of r_p=2-25 Mpc/h with r_0=6.61 Mpc/h and gamma=1.69 pm 0.07.  Estimate a quasar linear bias of b_Q=1.38 at this redshift from the X-corr measurements.  This linear bias corresponds to a characteristic host halo mass of 4e12 Msun/h, compared to 1e13 Msun/h characteristic host halo mass for CMASS galaxies.  Divide the quasar sample in luminosity and constrain the luminosity dependence of quasar bias to be db_Q/dlogL=0.20 or 0.11 (depending on different luminosity divisions) for quasar luminosities -23.5>M_i>-25.5, impling a weak luminosity dependence of quasar clustering for the bright end of thequasar population at <z>~0.5.  Compare meausrements with theoretical predictions, HOD models and mock catalogs.  These comparisons suggest quasars reside in a broad range of host haloes, and the host halo mass distirbutions significantly overlap with each other for quasars at different luminosities, implying a poor correlation between halo mass and instantaneous quasar luminosity.  Also find that the quasar HOD parameterization is largely degenerate such that different HODs can reproduce the CCF equally well, but with different outcomes such as the satellite fraction and host halo mass distribution.  These results highlight the imitations and ambiguities in modeling the distribution of quasars with the standard HOD approach and the need for additional information in populating quasars in DM haloes with HOD.

1212.4661
Modern cosmology: interactive computer simulations that use recent observational surveys
Moldenhauer et al

Open-source computational tools for numerically modeling large-scale observational data sets using modern cosmology theory.  Specifically, these tools will allow both students and researches to constrain the parameter values in competitive cosmological models, thereby discovering both the accelerated expansion of the universe and its composition (DM and DE).  These programs have several features to help the non-cosmologist build and understanding of cosmological models and their relation to observational data: a build-in collection of several real observational data sets; sliders to vary the values of the parameters that define different cosmological models; real-time plotting of simulated data, and chi2 calculations of the goodness of fit for each choice of parameters (theory) and observational data (experiment).  The current list of build-in observations includes several recent SNIa surveys, BAO, CMB, gamma-ray bursts, and measurements of the Hubble parameter.  In this article, discuss specific results for testing cosmological models using these observational data.  These programs can be found at its webpage.

1212.4726
Theoretical models of dark energy
Yoo, Watamabe

Solving fine-tuning and coincidence: quintessence, k-essence, coupled DE, and unified DE.  Compare these models by presenting attractive aspects, new rising problems and possible solutions.  Furthermore review modified gravity models that lead to late-time accelerated expansion without invoking a new form of DE; they contain f(R) gravity and the DGP model.  Discuss observational constraints on those models and on future modified gravity theories.  Review the inhomogeneous LTB model that drops and assumption of the spatial homogeneity of the Universe.  Also present basics of cosmology and scalar field theory, which are useful eSpecially for students and novices to understand DE models.

1212.4759
An improved model for the infrared emission from the zodiacal dust cloud: cometary, asteroidal and interstallar dust
Rowan-Robinson, May

Model the IR emission from zodiacal dust from IRAS and COBE, with the aim of estimating the relative contributions of asteroidal, cometary and interstellar dust to the zodiacal cloud. Most important result is the detection of an isotropic component of FG radiation due to interstellar dust.  The dust in the inner solar system is known to have a fan-dlike distribution.  If this is assumed to extend to the orbit of Mars, find that cometary, asteroidal and interstellar dust account for 70%, 22% and 7.5% of the dust in the fan.  Find a worse fit if the fan is assumed to extend to the orbit of Jupiter.  Model is broadly consistent with the analysis by Divine (1993) of interplanetary dust detected by Ulysses and other spacecraft.  Estimate of the mass-density of interstellar dust in the inner solar system is consistent with estimate fro Ulysses at 1.5 au, but is an order of magnitude higher than Ulysses estimates at r>4au.  Only 1% of the zodiacal dust arriving at the earth would be interstellar in this model.  Models can be further tested by ground-based kinematical studies of the zodiacal cloud, which need to extend over a period of years to monitor solar cycle variations in interstellar dust, by dynamical simulations, and by in situ measurements from spacecraft.

1212.4832
Multifractal analysis and lacunarity spectrum of the galaxies of the ninth Sloan digital sky survey (SDSS) data release
Chacon-Cardona, Casas-Miranda

Sample of 164k galaxies, use sliding-window technique to determine the multifractal dimension spectrum and its dependence on radial distance.  Generalization of the concept of fractal dimension is used to analyze large-scale clustering of matter in complex systems.  Likewise, the lacunarity spectrum, which is a quantity that complements the characterization of a fractal set by quantifying how the set fills the space in which it is embedded, is determined.  Using these statistical tools, find that the clustering of galaxies exhibits fractal behavior that depends on the radial distance for all calculated quantities.  A transition to homogeneity is not observed in the calculation of the fractal dimension of galaxies; instead, the galaxies exhibit a multifractal behavior whose dimensional spectrum does not exceed the physical spatial dimension for radial distances up to 180 Mpc/h from each center within the sample. Results and their implications are discussed in the context of the formation of large-scale structures in the Universe.

Day 359

Friday.  Meeting my sister's fiancé today.

1212.4492
Helium in natal HII regions: the origin of the X-ray absorption in gamma-ray burst afterglows
Watson et al

As the title says.  Soft X-ray absorption in excess of Galactic observed in GRBs were a mystery prior to this study.  Find He in GRB's host HII region is responsible for most of the absorption.  Show X-ray absorbing column density (N_Hx) is correlated with both the neutral gas column density and with the optical afterglow extinction (Av).  This correlation explains the connection between dark bursts and bursts with high N_Hx values.  Find that the correlation with the dust column has a strong z evolution, whereas the correlation with the neutral gas does not.  Column density of the X-ray absorption is correlated with the total gas column density in the host galaxy rather than the metal column density, in spite of the fact that X-ray absorption is typically dominated by metals.  The strong redshift absorption of X-rays in GRB afterglows is caused by He in the HII region hosting the GRB.  While dust is destroyed and metals are stripped of all of their electrons by the GRB to great distances, the abundance of He saturates the He-ionising UV continuum much closer to the GRB, allowing it to remain in the neutral or singly-ionised state.  Helium X-ray absorption explains the correlation with the total gas, the lack of strong evolution with redshift as well as the absence of dust, metal or hydrogen absorption features in the optical-UV spectra.

Day 358

Thursday.  Wayne Hu visits IPMU today.

[*]1212.4143
The dependence of the mass-size relation of early-type galaxies on environment in the local Universe
Huertas-Company, .. Mei, Bernardi, ... et al

ETG mass-size relation studied to understand how these galaxies have assembled their mass.  One key observational results of the last years is that massive galaxies increased their size by a factor of a few at fixed stellar mass from z~2.  Minor mergers have been put forward in hierarchical models as a plausible driver of this size growth.  Some of these models, predict a significant environmental dependence in the sense that galaxies residing in more massive haloes tend to be larger than galaxies in lower mass haloes, at fixed stellar mass and redshift.  At present observational results of this environmental dependence have been contradictory.  In this paper, revisit this issue in the local Universe, by carefully investigating how the sizes of massive ETGs depend on large-scale environment using an updated sample of massive ETGs (>1e11) in different environments - field, group, clusters - from SDSS DR7.  Observations do not show any environmental dependence of the sizes of central and satellite ETGs at fixed stellar mass.  The size-mass relation of early-type galaxies seems to be universal, independent of the mass of the host halo and of the position of the galaxy in that halo (central or satellite).  Compare observational results with two hierarchical models build from Millennium SIm.  Find results to broadly agree (w/in 1-2 sigma) with one of the models, but strongly disagree with the other (at 3 sigma), proving how useful environment is in testing galaxy evolution models.

[*]1212.4153
On the multiplicity of supernovae within host galaxies
Anderson, Soto

Investigate nature of multiple supernova hosting galaxies, and the types of events which they produce.  Using all known historical supernovae, split host galaxies into samples containing single or multiple events.  These samples are then characterized in terms of their relative SNe fractions, and host properties.  In multiple SNe hosts the ratio of type Ia to core-collapse events is lower than in single SNe hosts.  For core-collapse events there is a suggestion that the ratio of types Ibc to type II events is higher in multiples than within single SNe hosts.  This second increase is dominated by an increase in the number of SNIb.  Within multiple SNe hosts, SNe of any given type appear to 'prefer' to explode in galaxies that are host to the same type of SN.  Also find that multiple SN hosts have higher T-type morphologies [what is that?].  While these results suffer from low number statistics, speculate that their simplest interpretation is that SF within galaxies is generally of an episodic and bursty nature.  This leads to the SNe detected within any particular galaxy to be dominated by those with progenitors of a specific age, rather than a random selection from standard relative SNe rates, as the latter would be expected if SF was of a long-term continuous nature.  Further discuss the SNe progenitor and SF properties that may be important for understanding these trends, and also comment on a range of important selection effects within the sample.

1212.4157
Ellipsoidal halo finders and implications for models of triaxial halo formation
Despali, Tormen, Sheth

Describe an algorithm for identifying ellipsoidal haloes in numerical simulations, and quantify how the resulting estimates of halo mass and shape differ with respect to spherical halo finders.  Haloes become more prolate when fit with ellipsoids, the difference being most pronounced for the more aspherical objects.  Although the ellipsoidal mass is systematically larger, this is typically by less than 10% for most of the haloes [?].  However, even this small difference in mass corresponds to a significant difference in shape from the spherical counterpart.  Quantify these effects on the initial mass and deformation tensors, on which most models of triaxial collapse are based.  By studying the properties of protohaloes in the initial conditions, find that models in which protohaloes are identified in Lagrangian space by three positive eigenvalues of the deformation tensor are are tenable only at the masses well-above M*.  The overdensity delta within almost any protohalo is larger than the critical value associated with spherical collapse; this is in good qualitative agreement with models which identify haloes requiring that collapse have occurred along all 3 principal axes, each axis having turned around from the universal expansion at a different time.  On average, delta increases as mass M decreases, scaling as delta_c(1+0.2 sigma) with rms scatter 0.2 sigma(M).  The mean ellipticity e and prolateness p of the deformation tensor both increase as M decreases.

[*] 1212.4185
Distant galaxy clusters in the XMM large scale structure survey
Willis et al

Sample of 22 distant (z>0.8) galaxy clusters and cluster candidates from and overlap of XMM, CFHTLS and Spitzer SWIRE surveys.  Clusters are selected as extended X-ray sources with an accompanying overdensity of galaxies displaying optical to mid-infrared photometry consistent with z>0.8.  Nine clusters confirmed spectroscopic redshifts in the interval 0.8<z<1.2, 4 of which are new.  A further 11 candidate cluaters have between 8 and 10 band photometric redshifts in the interval 0.8<z<2.2, while the remaining 2 candidates do not have information in sufficient wavebands to generate a reliable photometric redshift.  All candidate clusters are new.  These clusters with NIR photometry display evidence for a RS galaxy population, determined either individually or via stacking, whose color is consistent with the expectation of an old, coeval stellar population observed at the cluster redshift.  Note that the sample displays a large range of red fraction values indicating that the clusters may be at different stages of red sequence assembly.  Compare the observed X-ray emission to the flux expected from a suite of model clusters and find that the sample displays an effective mass limit M200~1e14 Msun with all clusters displaying masses consistent with M200<5e14 Msun.  This XMM distant cluster study represents a complete sample of X-ray selected z>0.8 clusters.  [really?  complete?]

[*]1212.4359
Purring the precision in precision cosmology: how accurate should your data covariance matrix be?
Taylor, Joachimi, Kitching

Parameter estimation in cosmology requires that the likelihood function of the data is accurately known.  Assuming that cosmological large-scale structure power spectra data are multivariate Gaussian-distributed, we show the accuracy of parameter estimation is limited by the accuracy of the inverse data covariance matrix - the precision matrix.  If the data covariance and precision matrices are estimated by sampling independent realizations of the data, their statistical properties are described by the Wishart and Inverse-Wishart distributions, respectively.  Independent of any details of the survey, show that the fractional error on a parameter variance, or FoM, is equal to the fractional variance of the parameter error depends only on the difference between the number of independent realisations and the number of data points, and so can easily diverge.  For a 5% error on a parameter error and N_D << 100 data points, a minimum of 200 realisations of the survey are needed, with 10% accuracy for the data covariance.  If the number of data-points N_D>>100, need N_S > N_D realizations and a fractional accuracy of <sqrt(2/N_D) in the data covariance.  As the number of power spectra data points grows to N_D>1e4-6 this approach will be problematic.  We discuss possible ways to relax these conditions: improved theoretical modeling; shrinkage methods; data-compression; simulation and data resampling methods.

[*]1212.4433
Influence of baryonic physics in galaxy simulations: the molecular component
Halle, Combes

Role of baryon physics to solve the main problems encountered by the standard theory at the galactic scale, such as the galaxy stellar mass functions, or the missing satellites problem.  The present work aims at investigating in particular the role of the cold and dense molecular phase, which could play a role of gas reservoir in the outer galaxy discs, with low star formation efficiency.  Through TreeSPH simulations, implementing the cooling to low temperatures, and the inclusion of the molecular hydrogen component, several feedback efficiencies are studied, and results on the gas morphology and SF are obtained.  It is shown that molecular hydrogen allows some slow SF to occur in the outer parts of the discs.  This dense and quiescent phase might be a way to store a significant fraction of dark baryons, in a relatively long time-scale, in the complete baryonic cycle, connecting the galaxy discs to host gaseous haloes and to the cosmic filaments.

1212.4452
The escape fraction of ionizing radiation from primordial galaxies
Benson, Venkatesan, Shull

Escape of ionizing radiation from galaxies plays a critical role in the evolution of gas in galaxies, and the heating and ionization history of the IGM.  Present semi-analytic calculations of the escape fraction of ionizing radiation for both H and He from primordial galaxies, as well as analytic derivations of these quantities.  Consider variations in the galaxy density profile, source type, location, and spectrum, and gas clumping/distribution factors.  For sufficiently hard first-light sources, the He ionization fronts closely track or even advance beyond that of hydrogen.  Key new results in this work include calculations of the escape fractions for He I and He II ionizing radiation, and the impact of partial ionization from X-rays from early AGN or stellar clusters on the escape fractions from primordial haloes.  When factoring in frequency-dependent effects, find that X-rays play an important role in boosting the escape fractions for both H and He, but especially for He II.  Briefly discuss the implications of these results for recent observations of the He II reionization epoch at low redshifts, as well as the UV data and emission line signatures from early galaxies anticipated from future satellite missions.

Day 357

Wednesday.  In Japan.

1212.3610
The 6dF galaxy survey: dependence of halo occupation on stellar mass
Beutler, Blake, ... et al

NIR selection of 6dFGS gives more reliable stellar mass estimates compared to optical band.  Use HOD to investigate the trend of DM halo mass and satellite fraction with M* by measuring the projected correlation function w_p(r_p).  Find that the typical halo mass as well as the satellite power law index increase with stellar mass.  This indicates (1) that galaxies with higher stellar mass sit in more massive DM haloes and (2) that these more massive DM haloes accumulate satellites faster with growing mass compared to halos occupied by low stellar mass galaxies.  Find a relation between typical halo mass and the minimum DM halo mass relation of M ~ 22xM_min, in agreement with similar findings by SDSS.  Satellite fraction of 6dFGS galaxies declines with increasing M* from 21% at M*=2.6e10 Msun/h^2 to 12% at M*=5.4e10Msun/h^2, indicating that high M* galaxies are more likely to be central galaxies.  Compare results to 2 different SAM derived from Millennium simulation, finding some disagreement.  Data can be used to constrain SAM, particularly that of LRG satellites.  Compare results of HOD studies with gg WL studies.  Find good overall agreement, representing a valuable Xcheck for these two different tools for studying the matter distribution in the Universe.

1212.3615
Reconstructing the distribution of haloes and mock galaxies below the resolution limit in cosmological simulations
de la Torre, Peacock

Present a method for populating DM simulations with haloes of mass below the resolution limit.  Based on stochastically sampling a field derived from the density field of the halo catalogue, using constraints from the conditional halo mass function n(m|delta).  Test the accuracy of the method and show its application in the context of building mock galaxy samples.  Find that this technique allows precise reproduction of the 2-pt statistics of galaxies in mock samples constructed with this method.  Results demonstrate that the full information content of a simulation can be communicated efficiently using only a catalogue of the more massive halos.

1212.3642
A joint model of the X-ray and infrared extragalacitic backgrounds: I. Model construction and first results
Shi, et al

Model incorporates SF and SMBH accretion in a co-evolution scenario to fit simultaneously 617 data points of number counts, z distributions and local luminosity functions with 19 free parameters.  ... All variants of the model require that Compton-thick AGN fraction decrease with SMBH luminosity but increase with z while the type-1 AGN fraction has the reverse trend.

1212.3670
The local dark matter density
Nesti, Salucci

This method is based on the local equation of centrifugal equilibrium and depends on local and quite well known quantities such as the angular Sun's elocity, the disk to dark contribution to the circular velocity at the Sun and the think stellar disk scale length.  Result: rho = 0.43 GeV/cm^3.

1212.3691
Constraints on anisotropic cosmic expansion from supernovae
Kalus  et al

The fastest expansion is in the direction of (l,b) = (-35, -19) degrees with delta H/H ~0.026.

1212.3755
Signature of outflows in strong MgII absorbers in quasar sightlines
Sharma, et al

Velocity offset v/c = beta shows a power law increase with L_bol with a slope of 1/4.  Find that such a relation of beta with L_bol is expected for outflows driven by scattering of BH radiation by dust grains, and which are launched from the innermost dust survival radius.  Results indicate that a significant fraction of the strong MgII absorbers, in the range of beta = (0-0.4) are associated with the quasars themselves.

1212.3869
Evolution of the sizes of galaxies over 7<z<12 revealed by the 2012 Hubble Ultra Deep Field campaign
Ono, Ouchi, ... et al

Analyze the z- and L- dependent sizes of dropout galaxy candidates in 7<z<12 using deep images from the UDF12 campaign, data which offers two distinct advantages over that used in earlier work.  Provide improved size measurements for known galaxies at 6.5<z<8 in the HUDF.  Stack the new deep F140W image with the existing F125W data in order to provde improved measurements of the half-light radii of z-dropouts.  Similarly stack this image with the new deep UDF12 F160W image to obtain new size measurements for a sample of Y-dropouts.  Due to new data, sample at z>8 have been extended reliably to higher z.  For >15 sigma detections, confirm earlier indications that the average half-light of 7<z<12 galaxies are extremely small, 0.3-0.4 kpc, comparable to the sizes of gian moleular associations in local SF galaxies.  Also conform that there is a clear trend of decreasing half-light radius with increasing redshift, and provide the first evidence that this trend continues beyond z~8.  Modeling the evolution of the average half-light radius as a power-law (1+z)^s, obtain a best-fit index of s=-1.28pm0.13 over 4<z<12, mid-way between the physically expected evolution for baryons embedded in dark halos of constant mass (s=-1) and constant velocity (s=-1.5).  A clear size-luminosity relation, such as that found at lower redshift, is also evident in both our z- and Y-dropout sample.  This realization can be interpreted in terms of a constant surface density of SF over a range in luminosity of 0.05-1.0L*_z=3.

1212.3907
Gravitational lensing properties of isothermal universal halo profile
Er

N-body simulations predict that DM haloes with different mass scales are described by a universal model, the NFW density profiles.  As a consequence of baryonic cooling effects, the halos will become more concentrated, and similar to an isothermal sphere over large range in radii (~300 kpc/h).  The singular isothermal sphere model however has to be truncated artificially at large radii since it extends to infinity.  Model a massive galaxy halo as a combination of an isothermal sphere and an NFW density profile.  Give an approximation for the mass concentration at different baryon fractions and present exact expressions for the WL shear and flexion for such a halo.  Compare lensing properties with SIS and NFW profiles.  Find that the combined profile can generate higher order lensing signals at small radii and is more efficient in generating SL events.  In order to distinguish such a halo profile from the SIS or NFW profiles, one needs to combine strong and weak lensing constraints on small and large radii.

1212.4025
Perturbation theory for nonlinear halo power spectrum: the renormalized bias and halo bias
NIshizawa, Takada, Nishimichi

Revisit an analytical model to describe the halo-matter cross-power spectrum and the halo auto-power spectrum in the weakly NL regime, by combining the PT for matter clustering, the local bias model, and the halo bias.  Non-linearities in the power spectra arise from the NL clustering of matter as well as the NL relation between the matter and halo density fields.  By using the "renormalization" approach, express the NL power spectra by a sum of the two contributions: the NL matter PS with the effective linear bias parameter, and the higher-order PT spectra having the halo bias parameters as the coefficients.  The halo auto-power spectrum includes the residual shot noise contamination that needs to be treated as additional free parameter.  The terms of the higher-order PT spectra and the residual shot noise cause the scale-dependent bias function relative to the NL matter PS in the weakly NL regime.  Show that the model predictions are in good agreement with the spectra measured from a suit of high-resolution N-body simulations up to k~0.2 h/Mpc at z=0.35, for different halo mass bins.

1212.4097
Search for dark matter annihilations in the Sun with the 79-string IceCube detector
IceCube collaboration

Search for muon neutrinos from DM annihilation in the center of the Sun.  317 days of data, consistent with expected BG from atmospheric muons and neutrinos.  Upper limits set on hte DM annihilation rate, with conversions to limits on spin-dependent and spin-indepenednet WIMP-proton cross-sections for WIMP masses in the range 20-5000 GeV.  These are the most stringent limits to date above 35 GeV.

1212.4131
Planck intermediate results.  XI: the gas content of dark matter halos: the Sunyaev-Zeldovich-stellar mass relation for locally brightest galaxies
Planck Collaboration

Scaling relation between SZ signal and M* for 260k locally brightest galaxies from SDSS.  These are predominantly the central galaxies of their DM haloes.  Calibrate the stellar-t-halo mass conversion using realistic mock catalogues based on Millennium.  Measure the mean SZ signal down to M*~2e11 Msun, with a clear indication of signal at even lower stellar mass.  Derive the scaling relation between SZ signal and halo mass by assigning halo properties from mock catalogues to the real LBGs and simulation the Planck observation process.  This relation shows no evidence for deviation from a power law over a halo mass range extending from rich clusters down to M500~2e13 Msun, and there is a clear indication of signal down to M500 ~ 4e12 Msun.  Planck's SZ detections in such low-mass halos imply that about a quarter of all baryons have now been seen in the form of hot halo gas, and that this gas must be less concentrated than the DM in such halos in order to remain consistent with X-ray observations.  At the high-mass end, the measured SZ signal is 20% lower than found from observations of X-ray clusters, a difference consistent with Malmquist bias effects in the X-ray sample.  

1212.3608
Neutrino physics from future weak lensing surveys
Vanderveld, Hu

Shear deficit in 20-40% range, or rexcess in the 20-80% range cannot be explained by varioations in parameters of the flat LCDM model that are allowed by current observations of the expansion history from SNIa, BAO, and local measures of H0, coupled with WMAP and SPT.  Such a shear deficit or excess would indicate large masses or extra species, respectively, and find this to be independent of the flatness assumption [because it's matter clustering, I think].  Also discuss the robustness of these predictions to cosmic acceleration physics and the mans by which shear degeneracies in joint variation of mass and species can be broken.

1212.3612
Ripping apart at the seams: the network of stripped gas surrounding M86
Ehlert et al

Robust measurements of the temperature and metallicity structure of each galaxy along with the entire ~1 deg region between these galaxies.  Data suggest all 4 of these galaxies are undergoing ram pressure stripping by ICM, though manner of interaction is observationally distinct.  Nature of ram pressure stripping can vary significantly from site to site.

1212.3792
Limits in late time conversion of cold dark matter into hot dark matter
Motta, Boriero, de Holanda

Structure formation can generate a late time conversion of CDM into a relativistic form of DM (e.g., SNe event converts 99% of binding energy into relativistic neutrinos).  Alternative to the pure CDM model.

Day 356

Monday.  

1212.3327
CFHTLenS tomographic weak lensing: quantifying accurate redshift distributions
Benjamin, Van Waerbeke, Heymans, Kilbinger, Erben, Hildebrandt, Hoekstra, Kitching, Mellier, Miller, Rowe, Schrabback, ... Kuijken, Semboloni, et al



CFHTLenS: u*g'r'i'z' photometry: redshift probability distribution function summed over galaxies provides an accurate representation of the galaxy redshift distribution accounting for random and catastrophic errors for galaxies with best fitting photometric z_p<1.3.  Present cosmological constraints using tomographic WL by LSS.  Use 2 broad z bins 0.5<z_p<=0.85 and 0.85<z_p<=1.3 free of intrinsic alignment contamination, and measure the shear correlation function on angular scales in the range ~1-40 arcmin.  Show that the problematic z scaling of the signal does not affect th CFHTLenS data [why?].  For a flat LCDM model and Omega_m=0.27 (fixed), find the sigma_8=0.771 pm 0.041.  When combined with WMAP7, BOSS, and a prior on the Hubble constant from the HST distance ladder, find that CFHTLenS improves the precision of the fully marginalised parameter estimates by an average factor of 1.5-2.  Combining results with the above probes, find Omega_m=0.2762pm0.0074 and sigma_8=0.802 pm 0.013.

1212.3331
Remarkable spectral variability on the spin period of the accreting white dwarf in V455 And
Bloemen, et al

Spin-resolved spectroscopy of accreting WD binary: suggested spin period of 67s, one of the fastest spinning WDs known.  Study spectral variability on the spin period; 2s integration times.  Strong coherent signals detected in time series, leads to a robust determination of the spin period of the WD (67.619 pm 0.002 sec).  Folding the spectra on the WD spin period uncovered very complex emission line variations in H_gamma, He I and He II.  Attribute the observed spin sphase dependence of the emission line shape to the presence of magnetically controlled accretion onto the WD via accretion curtains, consistent with an intermediate polar type system.  No specific model that can quantitatively explain the complex velocity variations detected.  The orbital variations in the spectral lines indicate that the accretion disc of V455 And is rather structureless, contrary to the disk of the prototype of the intermediate polars, DQ Her.  This work demonstrates the potential of electron multiplying CCDs to observe faint targets at high cadence, as readout noise would make such a study impossible with conventional CCDs.

1212.3332
MegaMorph - multi-wavelength measurement of galaxy structure: complete S\'ersic profile information from modern surveys
Häußler, ... Nichol, et al

Find: fitting galaxy light profiles with multi-wavelength data increases the stability and accuracy of the measured parameters, and hence produces more complete and meaningful multi-wavelength photometry than has been available previously.  The improvement is particularly significant for magnitudes in low S/N bands and for structural parameters like half-light radius re and Sersic index n for which a prior is used by constraining these parameters to a polynomial as a function of wavelength.  This allows the fitting routines to push the magnitude of galaxies for which sensible values can be derived to fainter limits  The technique utilises a smooth transition of galaxy parameters with wavelength, creating more physically meaningful transitions than single-band fitting and allows accurate interpolation between passbands, perfect for derivation of rest-frame values.

1212.3336
The 70 month Swift-BAT All-sky hard X-ray survey
Baumgartner et al

1171 hard X-ray sources in the 14-195 keV band down to 5 sigma, associated with 1210 counterparts.  Down to flux level of 1.0e-11 erg/s/cm2 over 50% of the sky, and 1.3e-11 ergs/s/cm2 over 90% of the sky.  The majority of new sources i the 70-mo survey continue to be AGN, with >700 i the 70 mo survey catalog.  Also make available 8-channel spectra and monthly-sampled lightcurves for each object detected in the survey at the Swift-BAT 70 mo website.

[*]1212.3338
CFHTLenS:  Combined probe cosmological model comparison using 2d weak gravitational lensing
Kilbinger, Fu, Heymans, Benjamin, Erben, ... Hoekstra, Hildebrandt, Kitching, Mellier... et al

Cosmological constraints from 2d WL by LSS in CFHTLenS over 154 sq. deg in 5 optical bands.  4.2 million galaxies between 0.2<z<1.3, compute the 2d cosmic shear correlation function over angular scales from 0.8 to 350 arcmin.  Use NL models of DM PS, constrain cosmological parameters by exploring the parameter space with Population MC sampling.  Bets constraints from lensing alone are obtained for the small-scale density-fluctuations amplitude sigma_8 scaled with the total matter density Omega_m.  For a flat LCDM model, obtain sigma_8(Omega_m/0.27)^0.6 = 0.79 pm 0.03.  Combine the CFHTLenS with WMAP7, BOSS and HST Hubble distance-ladder constant prior to get joint constraints.  For a flat LCDM model, find Omega_m=0.283 pm 0.010 and sigma_8=0.813pm0.014.  In the case of a curved wCDM universe, obtain Omega_m = 0.27 pm 0.03, sigma_8=0.83pm0.04, w_0=-1.1pm0.15, and Omega_K=0.006 pm 0.006.  Calculate the Bayesian evidence to compare flat and curved LCDM and DE CDM models.  From the combination of all four probes, find models with curvature to be at moderately disfavoured with respect to the flat case.  A simple DE model is indistinguishable from LCDM.  Results therefore do not necessitate any deviations from the standard cosmological model.

[*]CFHTLenS: testing the laws of gravity with tomographic weak lensing and redshift space distortions
Simpson, Heymans, Parkinson, Blake, Kilbinger,... et al

WL and galaxy peculiar velocities provide complementary probes of GR, and in combination allow us to test modified theories of gravity in a unique way.  Combine WiggleZ and 6dFGS with CFHTLenS.  For scale-independent modifications to the metric potentials which evolve linearly with the effective DE density, find present-day cosmological deviations in the Newtonian potential and curvature potential from the prediction of GR to be Delta Psi/ Psi = 0.05 pm 0.25 and Delta Phi / Phi = -0.05 pm 0.3 respectively (1 sigma).

1212.3342
Deviation of stellar orbits from test particle trajectories around Sgr A* due to tides and winds
Psaltis, Li, Loeb

Effects of stellar winds are, in general, negligible.  On the other hand, the most eccentric orbits (e>0.96) for which an optical interferometer, such as GRAVITY, will detect orbital plane precession due to frame dragging, the tidal dissipation of orbital energy occurs at timescales comparable to the timescale of precession due to the quadrupole moment of the BH.  This non-conservative effect is a potential source of systematic uncertainty in testing the no-hair theorem with stellar orbits.

1212.3408
The dependence of tidal stripping efficiency on the satellite and host galaxy morphology
Chang, Maccio', Kang

Find that the host morphology and the orbital parameters have an effect on determining the mass removal, but they are of secondary importance with respect to satellite morphology; satellite morphology has a very strong effect on the efficiency of stellar stripping; should be taken into account in modeling galaxy formation and evolution.

1212.3438
Can we measure the slopes of density profiles in dwarf spheroidal galaxies?
Kowalzyk et al

The masses withing half-light radii obtained by Wolf+ are over(under)estimated by up to a factor of two when the LoS is along the longest (shortest) axis of the stellar component.  Divide the initial stellar distribution into an inner and outer population and trace their evolution in time.  The two populations retain different density profiles even after a faew Gyr.  Measure the half-light radii and velocity dispersions of the stars in the 2 populations along different lines of sight and use them to estimate the slope of the mass distribution in the dwarfs following the method proposed by Walker & Penarrubia.  The inferred slopes are systematically over- or underestimated, depending on the LoS.  When the dwarf is seen along the longest axis of the stellar component, a significantly shallower density profile is inferred than the real one measured from the simulations.  Since most dSphs are non-spherical and their orientation with respect to our LoS is unknown, the method can be reliably applied only to a large sample of dwarfs when these systematic errors are expected to be diminished.

1212.3514
Cosmological structure formation with augmented Lagrangian perturbation theory
Kitaura, Heß

For long range, use second order LPT (contains a tidal nonlocal and nonlinear term).  For short therm, use spherical collapse approximation.  Use a Gaussian filter with a smoothing radius r_S to separate between both regimes.  This method improves previous approximations at all scales, showing ~25% and ~75% higher correlation than 2LPT with the N-body solution at k=1 and 2 h/Mpc, respectively.  Conduct a parameter study to determine the optimal range of smoothing radii and find that the maximum correlation is achieved with r_S=4-5 h/Mpc.  This structure formation approach could be used for setting up IC for N-body sims, generating mock galaxy catalogs, perform cosmic web analysis, or for reconstructions of the primordial density fluctuations.

Day 355

Sunday.

1212.2985
First astroseismic limits on the nature of dark matter
Casanellas, Lopes

Weakly interacting low-mass DM particle constraints; the additional energy transport mechanism due to accumulated asymmetric DM particles modifies the central temperature and density of low-mass stars and suppresses the convective core expected in 1.1-1.3 Ms stars even for an environmental DM density as low as the expected in the solar neighborhood.  Compare to a few stars modeled astroseismically, rule out region of DM parameter space mass vs. spin-dependent DM-proton scattering cross section comparable with present experimental constraints.

1212.3082
The Planck Sunyaev-Zel'dovich vs. the X-ray view of the Coma cluster
Fusco-Femiano, Lapi, Cavaliere

Planck directly gauged the e- pressure profile in intracluster plasma from SZ effect, of Coma cluster.  This quantity may also be derived by combining the density and temperature provided by X-ray observations of the thermal bremsstrahlung radiation emitted by the plasma.  Find a model-independent tension between the SZ and the X-ray pressure, with the SZ one being definitely lower by 15-20%.  Propose that such a challenging tension can be resolved in terms of an additional, non-thermal support to the gravitational equilibrium of the intracluster plasma.  Possible origins of the nonthermal component include CR protons, ongoing turbulence, and relativistic electrons; given the existing observational constraints on the first two options, we focus on the third.  For this to be effective, find that the e- population must include not only an energetic tail accelerated to gamma>1e3 responsible for the Coma radio halo, but also many more, lower energy electrons.  The e- acceleration is to be started by merging events similar to hose which provided the very high central entropy of the thermal intracluster plasma in Coma.

1212.3207
The evolution of galaxy sizes
Poggianti, et al

Galaxies with radii and masses comparable to high-z massive and compact galaxies represent 4.4% of all galaxies more massive that 3e10Msun in the field.  Such galaxies are 3x more frequent in clusters than in the field.  Most of them are early-type galaxies with intermediate to old stellar populations.  There is a trend of smaller radii for older luminosity-weighted ages at fixed galaxy mass.  Show the relation between size and luminosity-weighted age for galaxies of different stellar masses and in different environments.  Compare with high- z data to quantify the evolution of galaxy sizes.  Find that, once the progenitor bias due to the relation between galaxy size and stellar age is removed, the average amount of size evolution of individual galaxies between high- and low-z is mild, of the order of 1.6x.  

1212.3230
Quasi-periodical features in the distribution of luminous red galaxies
Ryabinkov, Kaurov, Kaminker

LRG statistical analysis from SDSS DR7 with 0.16<z<0.47 carried out.  Find that the radial distribution incorporates a few quasi-periodical components relative to eta, the dimensionless line-of-sight comoving distance calculated for the LCDM cosmological model.  101 h/Mpc period dominant and represent BAO, 135 h/Mpc period also exists, which differs for LRG samples of different characteristic (luminosity).  Caveat: show that estimations of the significance levels of the peaks strongly depend on a smoothed radial function as well as characteristics of random fluctuations.

1212.3273
Earth and Mars crater size frequence distribution and impact rates: theoretical and observational analysis
Bruckman, Ruiz, Ramos

1 megaton one every 3 years for Mars; 10 megaton one every century for Earth, according to the model.  Model allows the derivation of an expression that gives the number of craters observed today as a function of D (crater diameter) and age.  The application of this expression to the Earth's crater data shows a remarkable agreement between theory and observations.

Day 354

Saturday.  Fun party at the Spleen last night.

1212.2639
The Carnegie-Irvine galaxy survey. III. The three-component structure of nearby elliptical galaxies
Huang, et al

Explore detailed photometric structure of a representative sample of 94 bright, nearby elliptical galaxies.  M* from 1e10.2 to 1e12.0 Msun.  Make 2d models to look for distinct substructures.  Find global light distribution of >75% of elliptical galaxies is not well described by a single Sersic function.  Instead, proposed that they generally contain 3 subcomponents: a compact <1kpc inner component with luminosity fraction of 0.1-0.15; an intermediate-scale ~2.5 kpc middle component with f~0.2-0.25; and a dominant (f=0.6), extended ~10 kpc outer envelope.  All subcomponents have average Sersic indices n~1-2, significantly lower than the values typically obtained from single-component fits.  The individual subcomponents follow well-defined photometric scaling relations and the stellar mass-size relation.  Discuss the physical nature of the substructures and their implications for the formation of massive elliptical galaxies.

1212.2650
Inferring the mass of sub-millimetre galaxies by exploiting their gravitational magnification of background galaxies
Hildebrandt, van Waerbeke, Scott, ... Cooray, .. Erben, ... et al

Dust emission at sub-millimetre wavelengths allows tracing of early phases of SF in the universe.  To understand the physical processes involved in this mode of SF [what mode?], it is essential to gain knowledge about the DM structures - most importantly their masses - that SMG live in [why?].  Use magnification effect of gravitational lensing to determine the average mass and dust content of SMG with 250 um flux densities of S_250>15mJy selected using data from the Herschel Multi-tiered Extragalactic Survey.  The positions of hundreds of SM foreground lenses are cross-correlated with the positions of BG Lyman-break galaxies at z~3-5 selected using optical data from CFHTLS.  Detect a cross-correlation signal at the 7-sigma level over a sky area of 1 sq deg, with 80% of this signal being due to magnification (the remaining 20% comes from dust extinction).  Adopting some simple assumptions fo the DM and dust profiles and the redshift distribution enables us to estimate the average mass of the haloes hosting the SMG to be log(M200/Msun)=13.7 pm 0.05 and their average dust mass fraction (at radii of >10kpc) to be Mdust/M200~6e-5.  This supports the picture that SMG are dusty, forming stars at a high rate, reside in massive group-sized haloes, and are a crucial phase in the assembly and evolution of structure in the universe.

1212.2675
Ca, Fe, and Mg trends among the within elliptical galaxies
Worthey, Ingermann, Serven

Ca/Fe and Ca/Mg systematically decrease with increasing elliptical galaxy mass.  Metallicity mixtures, age effects, stellar chromospheric emission effects, and low-mass IMF boost effects are ruled out as causes.    Feature gradients within galaxies imply a global Ca deficit rather than a radius-dependent phenomenon.  Some, but not all, SNII nucleosynthetic yield calculations indicate a decreasing Ca/Fe yield ratio in more massive SNe, lending possible support of the hypothesis that more massive elliptical galaxies have an IMF that favors more massive stars.  No SNII nucleosynthetic yield calculations show significant leverage in the Ca/Fe ratio as a function of progenitor metallicity.  It seems unlikely that the Ca behavior can be explained as a build-in metallicity effect, and this argues against explanations that vary only the Type II to Type Ia SNe enrichment ratio.

1212.2806
Reconstructing cosmological initial conditions from galaxy peculiar velocities.  I.  Reverse Zeldovich Approximation
Doumler, Hoffman, Courtois, Gottloeber

New method to recover the cosmological IC of the presently observed galaxy distribution (can serve to run constrained simulations of the LU).  The RZA method can be applied to radial galaxy peculiar velocity data and extends the previously used constraint realization method by adding a Lagrangian reconstruction step.  The RZA method consists of applying Zeldovich approximation in reverse to galaxy peculiar velocities to estimate the cosmic displacement field and the initial linear matter distribution from which the present-dat LU evolved.  Test our method with a mock survey taken from a cosmological simulation.  Show that the halo peculiar velocities at z=0 are close to the linear prediction of the Z approximation, if a grouping is applied to the data to remove virial motions.  The RZA is able to recover the correct initial positions of the velocity tracers with a median error of only 1.36 Mpc/h in the test simulation.  For realistic sparse and noisy data, this median increases to 5 Mpc/h.  This is a significant improvement over the previous approach of neglecting the displacement field, which introduces errors on a scale of 10 Mpc/h or even higher.  Applying the RZA method to the upcoming high-quality observational peculiar velocity catalogues will generate much more precise constrained simulations of the LU.

1212.2967
Hints on the nature of dark matter from the properties of Milky Way satellites
Anderhalden et al

At highly NL scales, strong astrophysical constraints can be set on the nature of the DM particle; e.g., satellite galaxies of MW.  Present results from a set of high-res simulations of a MW sized DM halo in 8 distinct cosmologies: CDM, WDM of 2keV particle; and 6 different cold+warm models (mass and fraction varied).  Test for total satellite abundance, their radial distribution and their mass profile.  Show that the requirement of simultaneously satisfying all 3 constraints sets very strong limits on the nature of DM [particle mass and total mass, I guess].  

1212.2968
Effects of power law primordial magnetic field on big bang nucleosynthesis
Yamazaki, Kusakabe

BBN affected by energy density of a primordial magnetic field (PMF).  Assume a power law distribution of PMF, then show a relation between PL-PMF parameters and the scale invariant strength of PMF.  Perform BBN calculation, show abundances as a function of eta.  The SI strength of the PMF is constrained from observational constraints on abundances of 4He and D.  Minimum abundance of 7Hi/H as a function of eta slightly moves to a higher value at larger eta value when a PMF exists during BBN.  ...

1212.2980
The size - virial radius relation of galaxies
Kravtsov

Sizes of galaxies are important diagnostic for galaxy formation models.  Use abundance matching ansatz to derive estimates of the virial radius, R200, for galaxies of different morphological types and wide range of stellar mass.  Show that over 8 orders of magnitude in M* galaxies of all morphological types follow an approximately linear relation between half-mass radius of their stellar distribuiton, r_half and virial radius, r_half ~ 0.015 R200, in remarkable agreement with expectation of models which assume that r_half lambda R200, where lambda is the spin of galaxy parent halo.  The scatter about the relation is comparable with the scatter expected from the distribution of lambda and normalization of the relation agrees with that predicted if galaxy sizes were set on average at 1<z<2.