26 research outputs found
The - and -to-stellar mass correlations of late- and early-type galaxies and their consistency with the observational mass functions
We compile and carrefully homogenize local galaxy samples with available
information on stellar, and/or masses, and morphology.
After processing the information on upper limits in the case of non gas
detections, we determine the - and -to-stellar mass
relations and their scatter for both late- and early-type galaxies.
The obtained relations are fitted to single or double power laws. Late-type
galaxies are significantly gas richer than early-type ones, specially at high
masses. The respective -to- mass ratios as a function of
are discussed. Further, we constrain the full mass-dependent
distribution functions of the - and -to-stellar mass ratios.
We find that they can be described by a Schechter function for late types and a
(broken) Schechter + uniform function for early types. By using the observed
galaxy stellar mass function and the volume-complete late-to-early-type galaxy
ratio as a function of , these empirical distribution functions are
mapped into and mass functions. The obtained mass
functions are consistent with those inferred from large surveys. The empirical
gas-to-stellar mass relations and their distributions for local late- and
early-type galaxies presented here can be used to constrain models and
simulations of galaxy evolution.Comment: 43 pages, 18 figures, to appear in RMxAA. Minor corrections
introduced. The presented results are optimal for comparisons with
theoretical predictions. Py-code to generate the HI- and H2-to-stellar mass
relations and their 1sigma scatter, as well as the full mass-dependent
distribution functions of the MHI/Ms and MH2/Ms ratios are available upon
request to A.R. Calett
CANDELS Sheds Light on the Environmental Quenching of Low-mass Galaxies
We investigate the environmental quenching of galaxies, especially those with
stellar masses (M*), beyond the local universe. Essentially
all local low-mass quenched galaxies (QGs) are believed to live close to
massive central galaxies, which is a demonstration of environmental quenching.
We use CANDELS data to test {\it whether or not} such a dwarf QG--massive
central galaxy connection exists beyond the local universe. To this purpose, we
only need a statistically representative, rather than a complete, sample of
low-mass galaxies, which enables our study to . For each low-mass
galaxy, we measure the projected distance () to its nearest massive
neighbor (M*) within a redshift range. At a given redshift
and M*, the environmental quenching effect is considered to be observed if the
distribution of QGs () is significantly skewed toward
lower values than that of star-forming galaxies (). For galaxies
with , such a difference between
and is detected up to . Also, about 10\%
of the quenched galaxies in our sample are located between two and four virial
radii () of the massive halos. The median projected distance from
low-mass QGs to their massive neighbors, , decreases with
satellite M* at , but increases with satellite M*
at . This trend suggests a smooth, if any,
transition of the quenching timescale around at
.Comment: 8 pages, 5 figures. ApJL accepted. Typos correcte
Astro2020: Empirically Constraining Galaxy Evolution
Over the past decade, empirical constraints on the galaxy-dark matter halo
connection have significantly advanced our understanding of galaxy evolution.
Past techniques have focused on connections between halo properties and galaxy
stellar mass and/or star formation rates. Empirical techniques in the next
decade will link halo assembly histories with galaxies' circumgalactic media,
supermassive black holes, morphologies, kinematics, sizes, colors,
metallicities, and transient rates. Uncovering these links will resolve many
critical uncertainties in galaxy formation and will enable much higher-fidelity
mock catalogs essential for interpreting observations. Achieving these results
will require broader and deeper spectroscopic coverage of galaxies and their
circumgalactic media; survey teams will also need to meet several criteria
(cross-comparisons, public access, and covariance matrices) to facilitate
combining data across different surveys. Acting on these recommendations will
continue enabling dramatic progress in both empirical modeling and galaxy
evolution for the next decade.Comment: Science white paper submitted to the Astro2020 Decadal Surve
Demographics of Star-forming Galaxies since z ⌠2.5. I. The <i>UVJ </i>Diagram in CANDELS
This is the first in a series of papers examining the demographics of
star-forming galaxies at in CANDELS. We study 9,100 galaxies from
GOODS-S and UDS having published values of redshifts, masses, star-formation
rates (SFRs), and dust attenuation () derived from UV-optical SED fitting.
In agreement with previous works, we find that the colors of a galaxy are
closely correlated with its specific star-formation rate (SSFR) and . We
define rotated coordinate axes, termed and
, that are parallel and perpendicular to the star-forming
sequence and derive a quantitative calibration that predicts SSFR from
with an accuracy of ~0.2 dex. SFRs from UV-optical fitting and
from UV+IR values based on Spitzer/MIPS 24 agree well overall,
but systematic differences of order 0.2 dex exist at high and low redshifts. A
novel plotting scheme conveys the evolution of multiple galaxy properties
simultaneously, and dust growth, as well as star-formation decline and
quenching, exhibit "mass-accelerated evolution" ("downsizing"). A population of
transition galaxies below the star-forming main sequence is identified. These
objects are located between star-forming and quiescent galaxies in space
and have lower and smaller radii than galaxies on the main sequence.
Their properties are consistent with their being in transit between the two
regions. The relative numbers of quenched, transition, and star-forming
galaxies are given as a function of mass and redshift.Comment: 36 pages, 26 figures, ApJ accepte
The Seventeenth Data Release of the Sloan Digital Sky Surveys: Complete Release of MaNGA, MaStar and APOGEE-2 Data
This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library (MaStar) accompanies this data, providing observations of almost 30,000 stars through the MaNGA instrument during bright time. DR17 also contains the complete release of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) survey which publicly releases infra-red spectra of over 650,000 stars. The main sample from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), as well as the sub-survey Time Domain Spectroscopic Survey (TDSS) data were fully released in DR16. New single-fiber optical spectroscopy released in DR17 is from the SPectroscipic IDentification of ERosita Survey (SPIDERS) sub-survey and the eBOSS-RM program. Along with the primary data sets, DR17 includes 25 new or updated Value Added Catalogs (VACs). This paper concludes the release of SDSS-IV survey data. SDSS continues into its fifth phase with observations already underway for the Milky Way Mapper (MWM), Local Volume Mapper (LVM) and Black Hole Mapper (BHM) surveys
Projection of the stellar to halo mass relation into the scaling relations of a disc galaxy population
Several pieces of evidence suggest that disk formation is the generic process of assembly of galaxies, while the spheroidal component arises from the merging/interactions of disks as well as from their secular evolution. To understand galaxy formation and evolution, a cosmological framework is required. The current cosmological paradigm is summarized in the so-called Î-cold dark matter model (ÎCDM). The statistical connection between the masses of the observed galaxies and those of the simulated CDM halos in large volumes leads us to the galaxy-halo mass relation, which summarizes the main astrophysical processes of galaxy formation and evolution (gas heating and cooling, SF, SN- and AGN-driven feedback, etc.). An important question is how this relation constrained by semi-empirical methods (e.g., Rodriguez-Puebla et al. 2014) is âprojectedâ into the disk galaxy scaling relations and other galaxy correlations. To explore this question, we generate a synthetic catalog of thousands of disk/halo systems by means of an extended Mo, Mao & White (1998) model, and by using as input the baryonic-to-halo mass relation, fbar(Mh), of local disk galaxy as recently constrained by Calette et al. (2015)