The Large Early Galaxy Astrophysics Census (LEGA-C) Data Release 2: Dynamical and Stellar Population Properties of z ≲ 1 Galaxies in the COSMOS Field

Straatman, Caroline; Wel, Arjen van der; Bezanson, Rachel; Pacifici, Camilla; Gallazzi, Anna; Wu, Po-Feng; Noeske, K. G.; Barišić, Ivana; Bell, Eric F.; Brammer, Gabriel; Calhau, João; Chauké, Priscilla; Franx, Marijn; Houdt, Josha van; Labbé, Ivo; Maseda, Michael V.; Muñoz-Mateos, J. C.; Muzzin, Adam; Sande, Jesse van de; Sobral, David; Spilker, Justin

doi:10.3847/1538-4365/aae37a

Cited by 96 publications

(122 citation statements)

References 92 publications

(89 reference statements)

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“…Cappellari 2017). We select galaxies with S/N higher than 10 per pixel at rest-frame 4000Å (SN RF 4000 ≥ 10) and quality flags f use = 1 in the LEGA-C DR2 catalog (Straatman et al 2018) to minimize mis-classification. The typical uncertainties in EW(Hδ) is ∼ 0.4Å.…”

Section: The Sample Of Recently Quenched Galaxiesmentioning

confidence: 99%

The Colors and Sizes of Recently Quenched Galaxies: A Result of Compact Starburst before Quenching

Wel

Bezanson

et al. 2020

ApJ

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We analyze the colors and sizes of 32 quiescent (UVJ-selected) galaxies with strong Balmer absorption (EW(Hδ) ≥ 4Å) at z ∼ 0.8 drawn from DR2 of the LEGA-C survey to test the hypothesis that these galaxies experienced compact, central starbursts before quenching. These recently quenched galaxies, usually referred to as post-starburst galaxies, span a wide range of colors and we find a clear correlation between color and half-light radius, such that bluer galaxies are smaller. We build simple toy models to explain this correlation: a normal star-forming disk plus a central, compact starburst component. Bursts with exponential decay timescale of ∼ 100 Myr that produce ∼ 10% to more than 100% of the pre-existing masses can reproduce the observed correlation. More significant bursts also produce bluer and smaller descendants. Our findings imply that when galaxies shut down star formation rapidly, they generally had experienced compact, starburst events and that the large, observed spread in sizes and colors mostly reflects a variety of burst strengths. Recently quenched galaxies should have younger stellar ages in the centers; multi-wavelength data with high spatial resolution are required to reveal the age gradient. Highly dissipative processes should be responsible for this type of formation history. While determining the mechanisms for individual galaxies is challenging, some recently quenched galaxies show signs of gravitational interactions, suggesting that mergers are likely an important mechanism in triggering the rapid shut-down of star-formation activities at z ∼ 0.8.

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Section: The Sample Of Recently Quenched Galaxiesmentioning

confidence: 99%

The Colors and Sizes of Recently Quenched Galaxies: A Result of Compact Starburst before Quenching

Wel

Bezanson

et al. 2020

ApJ

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“…Each galaxy is observed for ∼ 20 h, which results in spectra with S/N ∼ 20Å −1 (with resolution R ∼ 3000) in the wavelength range ∼ 0.6µm − 0.9µm. For details of the data reduction procedure, see van der Wel et al (2016) and Straatman et al (2018). This work is based on the second data release 1 , which contains 1550 primary sample galaxies.…”

Section: Datamentioning

confidence: 99%

Rejuvenation in z ∼ 0.8 Quiescent Galaxies in LEGA-C

Chauké

Wel

Pacifici

et al. 2019

ApJ

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We use reconstructed star-formation histories (SFHs) of quiescent galaxies at z = 0.6 − 1 in the LEGA-C survey to identify secondary star-formation episodes that, after an initial period of quiescence, moved the galaxies back to the star-forming main sequence (blue cloud). 16 ± 3% of the z ∼ 0.8 quiescent population has experienced such rejuvenation events in the redshift range 0.7 < z < 1.5 after reaching quiescence at some earlier time. On average, these galaxies first became quiescent at z = 1.2, and those that rejuvenated, remained quiescent for ∼ 1Gyr before their secondary SF episode which lasted ∼ 0.7Gyr. The stellar mass attributed to rejuvenation is on average 10% of the galaxy stellar mass, with rare instances of an increase of more than a factor 2. Overall, rejuvenation events only contribute ∼ 2% of the total stellar mass in z ∼ 0.8 quiescent galaxies and we conclude that rejuvenation is not an important evolutionary channel when considering the growth of the red sequence. However, our results complicate the interpretation of galaxy demographics in color space: the galaxies with rejuvenation events tend to lie in the so-called 'green valley', yet their progenitors were quiescent at z ∼ 2.

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“…The typical velocity resolution from the FMOS spectroscopy is ∼ 115 km s −1 . Straatman et al (2018): The Large Early Galaxy Astrophysics Census (LEGA-C) Data Release 2 provided redshifts from VLT/VIMOS observations. LEGA-C includes 1699 redshifts for objects in the COSMOS galaxy catalog; 554 objects also have redshifts from zCOSMOS.…”

Section: Trump Et Al (2009)mentioning

confidence: 99%

A Spectroscopic Census of X-Ray Systems in the COSMOS Field

Sohn

Geller

Zahid

2019

ApJ

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We investigate spectroscopic properties of galaxy systems identified based on deep X-ray observations in the COSMOS field. The COSMOS X-ray system catalog we use (George et al. 2011) includes 180 X-ray systems to a limiting flux of 1.0 × 10 −15 erg cm −2 s −1 , an order of magnitude deeper than future e-ROSITA survey. We identify spectroscopic members of these X-ray systems based on the spectroscopic catalog constructed by compiling various spectroscopic surveys including 277 new measurements; 137 X-ray systems are spectroscopically identified groups with more than three spectroscopic members. We identify 1843 spectroscopic redshifts of member candidates in these Xray systems. The X-ray luminosity (L X ) -velocity dispersion (σ v ) scaling relation of the COSMOS X-ray systems is consistent with that of massive X-ray clusters. One of the distinctive features of the COSMOS survey is that it covers the X-ray luminosity range where poor groups overlap the range for extended emission associated with individual quiescent galaxies. We assess the challenges posed by the complex morphology of the distribution of low X-ray luminosity systems, including groups and individual quiescent galaxies, in the L x − σ v plane.

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The Large Early Galaxy Astrophysics Census (LEGA-C) Data Release 2: Dynamical and Stellar Population Properties of z ≲ 1 Galaxies in the COSMOS Field

Cited by 96 publications

References 92 publications

The Colors and Sizes of Recently Quenched Galaxies: A Result of Compact Starburst before Quenching

The Colors and Sizes of Recently Quenched Galaxies: A Result of Compact Starburst before Quenching

Rejuvenation in z ∼ 0.8 Quiescent Galaxies in LEGA-C

A Spectroscopic Census of X-Ray Systems in the COSMOS Field

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