Effects of Environment on Galaxy Formation and Evolution

In this dissertation, I seek to advance our understanding of environment effects on galaxy formation and evolution. First, I use the deep near-infrared (IR) observation from the FourStar Galaxy Evolution Survey (ZFOURGE) and the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS) to derive the distribution of satellites (log(M/Mʘ > 9) around massive galaxies at 1 < z < 3 to provide constraints on the dark matter halo mass of massive galaxies with different star-formation activity (quiescent versus star-forming), and demonstrate that while halo mass may be an important mechanism for star formation suppression (“quenching”), it is unlikely to be the only factor. Second, to gain further understanding in star formation suppression in galaxies, I combine imaging from three deep near-infrared-selected surveys (ZFOURGE/CANDELS, UDS, and Ultra- VISTA) to study the correlation between star formation activity of massive central galaxies and their satellites out to~2:5. Satellites around quiescent centrals are more likely to be quenched compared to the satellites around star-forming centrals, demonstrating that satellite quenching is connected to the star formation properties of the central galaxy as well as to the mass of the halo. Third, I utilize the robust photometric redshift (Ơvz=(1+z) </~ 0:02) of ZFOURGE to accurately recover galaxies in low- and high-density environments and study of galactic star formation activity as a function of environmental density and stellar mass over 0.5<z<2.0. The strength of environmental quenching depends on galaxy stellar mass, indicating that the effects of quenching related to (stellar) mass and environment are not separable. The evolution of the environmental quenching favors models that combine gas starvation (as galaxies become satellites) with gas exhaustion through star-formation and outflows (“overconsumption”), and additional processes to account for the morphological differences between the quiescent and star-forming galaxy populations. Fourth, I apply The Tractor image modeling code to the vSpitzer/HETDEX Exploratory Large- Area (SHELA) survey, covering ~^ 24 deg2 of the Sloan Digital Sky Survey (SDSS) “Stripe82” region with spanning optical to mid-infrared wavelength. The new multi-band forced photometric catalogs provide several advantages over traditional position-matched catalog, including (1) consistent source cross-identification between bands, (2) deblending of sources that are clearly resolved in the higher resolution bands but blended in the lower resolution vSpitzer/IRAC bands, (3) detecting extremely faint sources that fall below the IRAC detection threshold, and (4) an improvement in the photometric redshift accuracy as evidenced by decreasing in bias and outlier fraction compared to spectroscopic redshifts. Finally, I demonstrate the utility of the multi-wavelength forced photometric catalogs constructed for SHELA survey. The large area (~17:5 deg^2) and moderate depth of SHELA survey drastically reduces the statistical uncertainties. After accounting for a number of potential systematic errors, I measure galaxy stellar mass functions (SMF) over 0:3 < z < 1:0 down to log(M.Mʘ) = 10:5 and find no evolution in the typical stellar mass over this redshift and stellar mass range with an uncertainty of 12%. This confidence interval is dominated by uncertainties in the assumed star formation history and stellar population synthesis models for stellar mass estimations. Similarly, I do not detect evolution (</~ 0:1 dex) in the typical stellar mass for massive quiescent galaxies (log(M.Mʘ ) > 11:0). Because quiescent galaxies are expected to lose mass through processes of stellar evolution, this implies massive galaxies continue to build up by merging at a rate that offsets the stellar mass loss. Lastly, the lack of evolution in the observed SMF provide the upper limit of mass growth by merging to be ~ 48% over 0:3 < z < 1:0

Effects of Environment on Galaxy Formation and Evolution

In this dissertation, I seek to advance our understanding of environment effects on galaxy formation and evolution. First, I use the deep near-infrared (IR) observation from the FourStar Galaxy Evolution Survey (ZFOURGE) and the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS) to derive the distribution of satellites (log(M/Mʘ > 9) around massive galaxies at 1 < z < 3 to provide constraints on the dark matter halo mass of massive galaxies with different star-formation activity (quiescent versus star-forming), and demonstrate that while halo mass may be an important mechanism for star formation suppression (“quenching”), it is unlikely to be the only factor. Second, to gain further understanding in star formation suppression in galaxies, I combine imaging from three deep near-infrared-selected surveys (ZFOURGE/CANDELS, UDS, and Ultra- VISTA) to study the correlation between star formation activity of massive central galaxies and their satellites out to~2:5. Satellites around quiescent centrals are more likely to be quenched compared to the satellites around star-forming centrals, demonstrating that satellite quenching is connected to the star formation properties of the central galaxy as well as to the mass of the halo. Third, I utilize the robust photometric redshift (Ơvz=(1+z) </~ 0:02) of ZFOURGE to accurately recover galaxies in low- and high-density environments and study of galactic star formation activity as a function of environmental density and stellar mass over 0.5<z<2.0. The strength of environmental quenching depends on galaxy stellar mass, indicating that the effects of quenching related to (stellar) mass and environment are not separable. The evolution of the environmental quenching favors models that combine gas starvation (as galaxies become satellites) with gas exhaustion through star-formation and outflows (“overconsumption”), and additional processes to account for the morphological differences between the quiescent and star-forming galaxy populations. Fourth, I apply The Tractor image modeling code to the vSpitzer/HETDEX Exploratory Large- Area (SHELA) survey, covering ~^ 24 deg2 of the Sloan Digital Sky Survey (SDSS) “Stripe82” region with spanning optical to mid-infrared wavelength. The new multi-band forced photometric catalogs provide several advantages over traditional position-matched catalog, including (1) consistent source cross-identification between bands, (2) deblending of sources that are clearly resolved in the higher resolution bands but blended in the lower resolution vSpitzer/IRAC bands, (3) detecting extremely faint sources that fall below the IRAC detection threshold, and (4) an improvement in the photometric redshift accuracy as evidenced by decreasing in bias and outlier fraction compared to spectroscopic redshifts. Finally, I demonstrate the utility of the multi-wavelength forced photometric catalogs constructed for SHELA survey. The large area (~17:5 deg^2) and moderate depth of SHELA survey drastically reduces the statistical uncertainties. After accounting for a number of potential systematic errors, I measure galaxy stellar mass functions (SMF) over 0:3 < z < 1:0 down to log(M.Mʘ) = 10:5 and find no evolution in the typical stellar mass over this redshift and stellar mass range with an uncertainty of 12%. This confidence interval is dominated by uncertainties in the assumed star formation history and stellar population synthesis models for stellar mass estimations. Similarly, I do not detect evolution (</~ 0:1 dex) in the typical stellar mass for massive quiescent galaxies (log(M.Mʘ ) > 11:0). Because quiescent galaxies are expected to lose mass through processes of stellar evolution, this implies massive galaxies continue to build up by merging at a rate that offsets the stellar mass loss. Lastly, the lack of evolution in the observed SMF provide the upper limit of mass growth by merging to be ~ 48% over 0:3 < z < 1:0

ZFOURGE: Using Composite Spectral Energy Distributions to Characterize Galaxy Populations at 1<z<4

We investigate the properties of galaxies as they shut off star formation over the 4 billion years surrounding peak cosmic star formation. To do this we categorize $\sim7000$ galaxies from $1<z<4$ into $90$ groups based on the shape of their spectral energy distributions (SEDs) and build composite SEDs with $R\sim 50$ resolution. These composite SEDs show a variety of spectral shapes and also show trends in parameters such as color, mass, star formation rate, and emission line equivalent width. Using emission line equivalent widths and strength of the 4000\AA\ break, $D(4000)$, we categorize the composite SEDs into five classes: extreme emission line, star-forming, transitioning, post-starburst, and quiescent galaxies. The transitioning population of galaxies show modest H$\alpha$ emission ($EW_{\rm REST}\sim40$\AA) compared to more typical star-forming composite SEDs at $\log_{10}(M/M_\odot)\sim10.5$ ($EW_{\rm REST}\sim80$\AA). Together with their smaller sizes (3 kpc vs. 4 kpc) and higher S\'ersic indices (2.7 vs. 1.5), this indicates that morphological changes initiate before the cessation of star formation. The transitional group shows a strong increase of over one dex in number density from $z\sim3$ to $z\sim1$, similar to the growth in the quiescent population, while post-starburst galaxies become rarer at $z\lesssim1.5$. We calculate average quenching timescales of 1.6 Gyr at $z\sim1.5$ and 0.9 Gyr at $z\sim2.5$ and conclude that a fast quenching mechanism producing post-starbursts dominated the quenching of galaxies at early times, while a slower process has become more common since $z\sim2$.Comment: Accepted for publication in The Astrophysical Journa

Investigating the growing population of massive quiescent galaxies at cosmic noon

We explore the build-up of quiescent galaxies using a sample of 28 469 massive (M⋆ ≥ 1011 M☉) galaxies at redshifts 1.5 < zz < 3.0, drawn from a 17.5 deg2 area (0.33 Gpc3 comoving volume at these redshifts). This allows for a robust study of the quiescent fraction as a function of mass at 1.5 < zz < 3.0 with a sample ∼40 times larger at log(M⋆/ M⊙)≥11.5M⊙)≥11.5 than previous studies. We derive the quiescent fraction using three methods: specific star formation rate, distance from the main sequence, and UVJ colour-colour selection. All three methods give similar values at 1.5 < zz < 2.0, however the results differ by up to a factor of 2 at 2.0 < zz < 3.0. At redshifts 1.5 < zz < 3.0, the quiescent fraction increases as a function of stellar mass. By zz = 2, only 3.3 Gyr after the big bang, the universe has quenched ∼25 per cent of M⋆ = 1011 M☉ galaxies and ∼45 per cent of M⋆ = 1012 M☉ galaxies. We discuss physical mechanisms across a range of epochs and environments that could explain our results. We compare our results with predictions from hydrodynamical simulations SIMBA and IllustrisTNG and semi-analytic models (SAMs) SAG, SAGE, and Galacticus. The quiescent fraction from IllustrisTNG is higher than our empirical result by a factor of 2-5, while those from SIMBA and the three SAMs are lower by a factor of 1.5-10 at 1.5 < zz < 3.0Fil: Sherman, Sydney. Department Of Astronomy; Estados UnidosFil: Jogee, Shardha. Department Of Astronomy; Estados UnidosFil: Florez, Jonathan. Department Of Astronomy; Estados UnidosFil: Stevans, Matthew L. Department Of Astronomy; Estados UnidosFil: Kawinwanichakij, Lalitwadee. Kavli Institute For The Physics And Mathematics Of The; JapónFil: Wold, Isak. Nasa Goddard Space Flight Center; Estados UnidosFil: Finkelstein, Steven L. Department Of Astronomy; Estados UnidosFil: Papovich, Casey. Department Of Physics And Astronomy; Estados UnidosFil: Ciardullo, Robin. Department Of Astronomy And Astrophysics; Estados UnidosFil: Gronwall, Caryl. Department Of Astronomy And Astrophysics; Estados UnidosFil: Cora, Sofia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Hough, Tomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Vega Martínez, Cristian Antonio. Instituto de Investigación Multidisciplinar En Ciencia; Chil