Radial Color Gradients in K + A Galaxies in Distant Clusters of Galaxies

Bartholomew, L. J.; Rose, James A.; Gaba, Alejandro E.; Caldwell, Nelson

doi:10.1086/324229

Cited by 21 publications

(32 citation statements)

References 48 publications

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“…Typical mean errors are CGE $ 0:045. cluster galaxies are consistent with populations of galaxies found in distant (z > 0:3) clusters showing enhanced Balmer absorption spectra (Couch & Sharples 1987;Barger et al 1996). Additionally, Bartholomew et al (2001) found that distant cluster galaxies with strong Balmer absorption have blue color gradients and are presumed to be a poststarburst population (Caldwell & Rose 1998;Poggianti et al 1999). Furthermore, Rose et al (2001) found that currently starforming galaxies in local clusters often show blue cores and have more centrally concentrated emission lines than field galaxies.…”

Section: Estimated Color Gradientssupporting

confidence: 74%

Structural Evidence for Environment‐driven Transformation of the Blue Galaxies in Local Abell Clusters: A85, A496, and A754

McIntosh

Rix

Caldwell

2004

ApJ

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We present a detailed comparison of structural properties in the rest-frame V band of cluster and field galaxies, selected and analyzed in the same manner, to test the hypothesis that much of the current cluster galaxy membership resulted from the fairly rapid (1-2 Gyr) transformation of infalling, field spirals into red, cluster early types. Specifically, we have selected $140 galaxies from three nearby Abell clusters (A85, A496, and A754) that have colors significantly bluer than the red sequence population and compared them to $80 field galaxies with similar colors and luminosities from the Nearby Field Galaxy Survey. The comparison is based on the hypothesis that recent (1-4 Gyr) cluster arrivals were originally blue and star-forming, then stopped forming stars to dim and redden in a few gigayears. For the comparison we quantify galaxy internal structure and morphology from twodimensional bulge/disk decompositions using GIM2D. We observe structural differences between blue galaxies in local (z < 0:06) clusters, compared to field environments. All cluster galaxies have spectroscopic membership. The majority of blue cluster members, presumably recent additions, are physically smaller and fainter than their equally colored field counterparts. At a matched size and luminosity, the newer cluster arrivals are quantifiably smoother in appearance, yet their total light is as disk dominated as in normal field spirals. Moreover, half of the blue cluster members appear to have blue cores or globally blue color profiles, in contrast with field spirals, which typically exhibit red inward color gradients. Blue cores suggest enhanced nuclear star formation, possibly a starburst, while uniformly blue profiles are consistent with an episode of fairly strong global star formation in the past few gigayears. Our previous work shows that the blue membership of local clusters is a recently infalling population that has yet to encounter the dense core. In a universe without environmentally dependent evolution outside of cluster cores, we would expect blue disk galaxies inhabiting field and cluster regions to have similar morphology, size, and color gradient distributions. Our findings show conclusively not only that the abundance of red and blue galaxies depends on environment, but also that fundamental structural and morphological galaxy properties do indeed reflect the environment in which the galaxy is found. Moreover, the data show that the transformation of accreted galaxies is not confined to the dense cluster core. The overall properties of bluer cluster members are best explained by environment-driven transformation of accreted field spirals, and our results suggest that the processes that govern color and morphological evolution occur separately.

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Section: Estimated Color Gradientssupporting

confidence: 74%

Structural Evidence for Environment‐driven Transformation of the Blue Galaxies in Local Abell Clusters: A85, A496, and A754

McIntosh

Rix

Caldwell

2004

ApJ

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“…However, the origin of E+A galaxies with negative colour gradients – which are observed both in the field and in clusters (e.g. Bartholomew et al 2001; Yang et al 2004) – remains unclear. In particular, the central red colours in E+A galaxies with negative Hδ gradients (e.g.…”

Section: Discussionmentioning

confidence: 99%

Origin of E+A galaxies - I. Physical properties of E+A galaxies formed from galaxy merging and interaction

Bekki

Couch

Shioya

et al. 2005

Monthly Notices of the Royal Astronomical Society

111

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We investigate the structural, kinematical and spectrophotometric properties of ‘E+A’ galaxies – those with strong Balmer absorption lines but no significant [O ii] emission – using numerical simulations combined with stellar population synthesis codes. We particularly focus on the two‐dimensional (2D) distributions of line‐of‐sight velocity, velocity dispersion, colour and line index in E+A galaxies formed via the interaction and merging of two gas‐rich spirals. Our numerical simulations demonstrate that E+A elliptical galaxies formed by major galaxy merging have positive radial colour gradients and negative radial Hδ gradients by virtue of their central post‐starburst populations. Furthermore, we show that the projected kinematical and spectroscopic properties of the simulated E+A galaxies can be remarkably different for different major merger models. For example, the simulated E+A ellipticals with kinematically decoupled cores clearly show regions of strong Hδ absorption which are very flattened, with differences in rotation and velocity dispersion between the old and young stars. E+A ellipticals are highly likely to show more rapid rotation and a smaller central velocity dispersion in young stars than in old ones. E+A galaxies formed from the strong tidal interaction between gas‐rich spirals have discy morphologies with thick discs and are highly likely to be morphologically classified as barred S0 galaxies. We also provide specific predictions on the structural, kinematical and spectrophotometric properties of young globular cluster systems in E+A galaxies. Based on these results, we discuss the importance of spatially resolved, integral field unit spectroscopy on large (8–10 m) ground‐based telescopes in confirming the formation of kinematically distinct cores in elliptical galaxies produced via dissipative merging and determining the most probable physical mechanism(s) for E+A formation with discy and spheroidal morphologies.

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“…A steepening of colour gradients with galaxy luminosity has been unfruitfully looked for by various studies (e.g. Peletier et al 1990a;Bartholomew et al 2001). Recently, Tamura & Ohta (2003) measured the optical colour gradients for N = 36 galaxies at z ∼ 0.…”

Section: Discussionmentioning

confidence: 99%

Probing galaxy evolution through the internal colour gradients, the Kormendy relations and the Photometric Plane of cluster galaxies at z ~ 0.2

Barbera

Merluzzi

Busarello

et al. 2004

A&A

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Abstract. We present a detailed analysis of the photometric properties of galaxies in the cluster A 2163B at redshift z ∼ 0.2. R-, I-and K-band structural parameters, (half light radius R e , mean surface brightness µ e within R e and Sersic index n) are derived for N ∼ 60 galaxies, and are used to study their internal colour gradients. For the first time, we use the slopes of optical-NIR Kormendy relations to study colour gradients as a function of galaxy size, and we derive the Photometric Plane at z ∼ 0.2 in the K band. Colour gradients are negligible at optical wavelengths, and are negative in the optical-NIR, amounting on average to −0.48 ± 0.06. This result is in agreement with our previous measurements of colour gradients at intermediate redshifts, and imply a metallicity gradient in galaxies of ∼0.2 dex per radial decade. The analysis of the Kormendy relation suggests that its slope increases from the optical to the NIR, implying that colour gradients do not vary or even do become less steep in more massive galaxies. Such a result is not simply accomodated within a monolithic collapse scenario, while it can be well understood within a hierarchical merging framework. Finally, we derive the first NIR Photometric Plane at z ∼ 0.2, accounting for both the correlations on the measurement uncertainties and the selection effects. The Photometric Plane at z ∼ 0.2 is consistent with that at z ∼ 0, with an intrinsic scatter significantly smaller than the Kormendy relation but larger than the Fundamental Plane.

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Radial Color Gradients in K + A Galaxies in Distant Clusters of Galaxies

Cited by 21 publications

References 48 publications

Structural Evidence for Environment‐driven Transformation of the Blue Galaxies in Local Abell Clusters: A85, A496, and A754

Structural Evidence for Environment‐driven Transformation of the Blue Galaxies in Local Abell Clusters: A85, A496, and A754

Origin of E+A galaxies - I. Physical properties of E+A galaxies formed from galaxy merging and interaction

Probing galaxy evolution through the internal colour gradients, the Kormendy relations and the Photometric Plane of cluster galaxies at z ~ 0.2

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