Day 961

Monday.


1509.01250
Push it to the limit: local group constraints on high-redshift stellar mass functions for Mstar>1e5 Msun
Graus, Bullock, Boylan-Kolchin, Weisz

Constrain the evolution of the galaxy stellar mass function from 2<z<5 for galaxies with stellar masses as low as 1e5 Msun by combining SFHs of MW satellite galaxies derived from deep HST observations with merger trees from the ELIVS suite of N-body sims.  This approach extends the understanding more than 2 orders of magnitude lower n stellar mass than is currently possible by direct imaging.  Find the faint end slopes of the mass functions to be alpha=-1.42±0.05 at z=2 and alpha=-1.57±0.06 at z=5, and show the slope only weakly evolves from z=5 to z=0.  The findings are in stark contrast to a number of direct detection studies that suggest slopes as steep as alpha=-1.9 at these epochs.  Such a steep slope would result in an order of magnitude too many luminous MW satellites in a mass regime that is observationally complete (M*>2e5 Msun at z=0).  The most recent studies from ZFOURGE and CANDELS also suggest flatter faint end slopes that are consistent with the results, but with a lower degree of precision.  This work illustrates the strong connections between low and high-z observations when viewed through the lens of LCDM numerical simulations.


1509.01276
The Stripe 82 massive galaxy project I: catalog construction
Bundy, Leauthaud, Sito, Bolton, Lin,  et al

S82-MGC (Massive Galaxy Catalog) is the largest-volume stellar mass-limited sample of galaxies beyond z~1 constructed to date.  Spanning 139.4 deg2, the s82-MGC includes a mass-limited sample of 41,770 galaxies with logMstar>11.2 to z~0.7, sampling a volume of 0.3 Gpc3, roughly equivalent to the volume of SDSS-I/II z<0.15 MAIN sample.  The catalog is built on 3 pillars of survey data: the SDSS Stripe 82 Coadd photometry which reaches r-band magnitudes of 23.5 AB, YJHK photometry at depths of 20th magnitude (AB) from UKIDSS Large Area Survey, and over 70k spectroscopic galaxy redshifts from SDSS-I/II and BOSS.  Describe the catalog construction and verification, the production of 9-band matched aperture photometry, tests of existing and newly estimated photometric redshifts required to supplement spectroscopic redshifts for 55% of the logMstar>11.2 sample, and geometric masking. Provide NIR based stellar mass estimates and compare these to previous estimates.  All catalog products are made publicly available.  The S82-MGC not only addresses previous statistical limitations in high-mass galaxy evolution studies but begins tackling inherent data challenges in the coming era of wide-field imaging surveys.


1509.01279
A Keck adaptive optics survey of a representative sample of gravitationally-lensed star-forming galaxies: high spatial resolution suited of kinematics and metallicity gradients
Leethochawalit, Jones, Ellis, Stark, Richard, Zitrin, Auger

15 GL SF galaxies at z~2 with spatially resolved emission line spectroscopy. ... Data indicates a more diverse range of kinematic and metal gradient behavior inconsistent with a smile picture of well-ordered rotation developing concurrently with established steep metal greatness in all but merging systems.  Comparing the observations with the predictions of hydrodynamical sims suggests that strong feedback plays a key role in flattening metal gradients in early SF galaxies.


1509.01322
Cosmology and astrophysics from relaxed galaxy clusters III: thermodynamic profiles and scaling relations
Mantz, Allen, Morris, Schmidt

Sample comprises 40 clusters as being dynamically relaxed and hot (papers I, II).  In this paper, consider the thermodynamics of the ICM, in particular the profile of density, temperature and related quantities, as well as integrated measurements of gas mass, average temperature, total luminosity and center-excluded luminosity.  Fit power-law scaling relations of each of these quantities as a function of z and cluster mass, which can be measured precisely and with minimum bias for these relaxed clusters.  For the thermodynamic profiles, jointly model the density and temperature and their intrinsic scatter as a function of radius, thus also capturing the behavior of the gas pressure and entropy.  For the integrated quantities, also jointly fit a multidimensional intrinsic covariance, providing the first observational constraints on many of the off-diagonal terms of the covariance matrix.  The results reinforce the view that self similar theory provides a good description of relaxed cluster outside their centers (radii r>0.5 r_2500 ~ 0.15 r_500), but that some combination of heating and cooling processes breaks self similarity within those centers.  As cosmo tests using clusters continue to improve, statistical models with the power and flexibility to reflect the internal astrophysics of cluster formation and evolution will be needed; the analysis presented here is a step in that direction.