The evolution of galaxies in radio-selected groups

Allington‐Smith, J. R.; Ellis, Richard S.; Zirbel, Esther; Oemler, Augustus

doi:10.1086/172305

Cited by 82 publications

(97 citation statements)

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“…Using the Morphs data, Ellis et al (1997) find a remarkably small scatter (<0.07 mag in rest-frame U-V) in the colours of the elliptical population, even across different clusters, at z≃0.5 (see Stanford et al 1997 for an extension over a wider redshift range). The bulk of this population must be passively-evolving systems whose stars formed at an early time (z >3) in broad agreement with earlier ground-based work (Aragon-Salamanca et al 1993). Similar constraints are now emerging from fundamental plane (Mg -σ and r e -σ) relations pursued to high redshift (van Dokkum & Franx 1996, Bender et al 1997.…”

Section: The Role Of the Environmentsupporting

confidence: 82%

The Formation and Evolution of Galaxies: Perspectives on the Origin of the Hubble Sequence

Ellis¹

1999

Symp. - Int. Astron. Union

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Abstract. I review recent observational progress concerning the evolution of the morphological distribution of galaxies in the rich cluster environment and in the faint field population. By coupling HST imagery with ground-based spectroscopic diagnostics, evidence accumulates that galaxy morphology can be a transient phenomenon reflecting various changes in the star formation rate. Possible physical processes responsible for these changes are discussed. Future progress in understanding them will depend on securing 2-D spectroscopic data for representative systems. 1

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Section: The Role Of the Environmentsupporting

confidence: 82%

The Formation and Evolution of Galaxies: Perspectives on the Origin of the Hubble Sequence

Ellis¹

1999

Symp. - Int. Astron. Union

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“…However, the fact that at least some of the environmental differentiation has occurred at recent epochs (BO78, Dressler et al 1997, Allington-Smith et al 1993, McGee et al 2011 suggests-although it does not require-that much evolution is driven by the continuing interaction of galaxies with their surroundings. Many such processes have been suggested, including shutoff of the external gas supply (LTC80), stripping of gas by a hot external medium (Gunn & Gott 1972), tidal encounters (Richstone & Malmuth 1983, Byrd & Valtonen 1990, Moore et al 1996, and mergers with other galaxies (Dressler et al 1999, Struck 2006.…”

Section: Introductionmentioning

confidence: 99%

The Star Formation Histories of Disk Galaxies: The Live, the Dead, and the Undead

Oemler¹,

Abramson²,

Gladders

et al. 2017

ApJ

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We reexamine the systematic properties of local galaxy populations, using published surveys of star formation, structure and gas content. After recalibrating star formation measures, we are able to reliably measure specific star formation rates well below that of the so-called "main sequence" of star formation vs mass. We find an unexpectedly large population of galaxies with star formation rates intermediate between vigorously star-forming main sequence galaxies and passive galaxies, and with gas content disproportionately high for their star formation rates. Several lines of evidence suggest that these quiescent galaxies form a distinct population rather than a low star formation tail of the main sequence. We demonstrate that a tight main sequence, evolving with epoch as it is observed to do, is a natural outcome of most histories of star formation and has little astrophysical significance, but that the quiescent population requires additional astrophysics to explain its properties. Using a simple model for disk evolution based on the observed dependence of star formation on gas content in local galaxies, and assuming simple histories of cold gas inflow, we show that the evolution of galaxies away from the main sequence can be attributed to the depletion of gas due to star formation after a cutoff of gas inflow. The quiescent population is composed of galaxies in which the density of disk gas has fallen below a threshold for disk stability. The evolution of galaxies beyond the quiescent state to gas exhaustion and a complete end of star formation requires another process, probably wind-driven mass loss. The SSFR distribution of the quiescent and passive galaxies implies that the timescale of this process must be long, greater than a few Gyr, but less than a few tens of Gyrs. The environmental dependence of the three galaxy populations is consistent with recent numerical modeling which indicates that cold gas inflows into galaxies are truncated at earlier epochs in denser environments.

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“…(Dressler & Gunn 1982, 1992Lavery & Henry 1986, 1988Fabricant et al 1991;Poggianti et al 1999Poggianti et al , 2006Ellingson et al 2001), has been extended to groups (Allington-Smith et al 1993;Wilman et al 2005a;Gerke et al 2007;Cucciati et al 2009b), and critically discussed in the context of selection biases (Andreon & Ettori 1999;Andreon et al 2004Andreon et al , 2006.…”

Section: Introductionmentioning

confidence: 99%

The zCOSMOS redshift survey: how group environment alters global downsizing trends

Iovino¹,

Cucciati

Scodeggio

et al. 2009

A&A

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Context. Groups of galaxies are a common environment, bridging the gap between starforming field galaxies and quiescent cluster galaxies. Within groups secular processes could be at play, contributing to the observed strong decrease of star formation with cosmic time in the global galaxy population. Aims. We took advantage of the wealth of information provided by the first ∼10 000 galaxies of the zCOSMOS-bright survey and its group catalogue to study in detail the complex interplay between group environment and galaxy properties. Methods. The classical indicator F blue , i.e., the fraction of blue galaxies, proved to be a simple but powerful diagnostic tool. We studied its variation for different luminosity and mass selected galaxy samples, divided as to define groups/field/isolated galaxy subsamples. Results. Using rest-frame evolving B-band volume-limited samples, the groups galaxy population exhibits significant blueing as redshift increases, but maintains a systematic difference (a lower F blue ) with respect to the global galaxy population, and an even larger difference with respect to the isolated galaxy population. However moving to mass selected samples it becomes apparent that such differences are largely due to the biased view imposed by the B-band luminosity selection, being driven by the population of lower mass, bright blue galaxies for which we miss the redder, equally low mass, counterparts. By carefully focusing the analysis on narrow mass bins such that mass segregation becomes negligible we find that only for the lowest mass bin explored, i.e., log(M * /M ) ≤ 10.6, does a significant residual difference in color remain as a function of environment, while this difference becomes negligible toward higher masses. Conclusions. Our results indicate that red galaxies of mass log(M * /M ) ≥ 10.8 are already in place at z ∼ 1 and do not exhibit any strong environmental dependence, possibly originating from so-called nature or internal mechanisms. In contrast, for lower galaxy masses and redshifts lower than z ∼ 1, we observe the emergence in groups of a population of nurture red galaxies: slightly deviating from the trend of the downsizing scenario followed by the global galaxy population, and more so with cosmic time. These galaxies exhibit signatures of group-related secular physical mechanisms directly influencing galaxy evolution. Our analysis implies that these mechanisms begin to significantly influence galaxy evolution after z ∼ 1, a redshift corresponding to the emergence of structures in which these mechanisms take place.

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The evolution of galaxies in radio-selected groups

Cited by 82 publications

References 0 publications

The Formation and Evolution of Galaxies: Perspectives on the Origin of the Hubble Sequence

The Formation and Evolution of Galaxies: Perspectives on the Origin of the Hubble Sequence

The Star Formation Histories of Disk Galaxies: The Live, the Dead, and the Undead

The zCOSMOS redshift survey: how group environment alters global downsizing trends

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