RXJ0142.0+2131: I. The galaxy content of an X-ray-luminous galaxy cluster at z=0.28

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dc.creatorBarr, Jordi
dc.creatorDavies, Roger
dc.creatorJorgensen, Inger
dc.creatorBergmann, Marcel
dc.creatorCrampton, David
dc.date2005-04-04
dc.date.accessioned2026-07-07T11:29:40Z
dc.date.available2026-07-07T11:29:40Z
dc.descriptionWe present a photometric and spectroscopic study of stellar populations in the X-ray-luminous cluster of galaxies RXJ0142.0+2131 at z=0.280. This paper analyses the results of high signal-to-noise spectroscopy, as well as g'-, r'-, and i'-band imaging, using the Gemini Multi-Object Spectrograph on Gemini North. Of 43 spectroscopic targets, we find 30 cluster members over a range in color. Central velocity dispersions and absorption-line strengths for lines in the range 3700A < lambda_rest < 5800A are derived for cluster members, and are compared with a low-redshift sample of cluster galaxies, and single stellar population (SSP) models. We use a combination of these indicators to estimate luminosity-weighted mean ages, metallicities ([M/H]), and alpha-element abundance ratios ([alpha/Fe]). RXJ0142.0+2131 is a relatively poor cluster and lacks galaxies with high central velocity dispersions. Although the red sequence and the Faber-Jackson relation are consistent with pure passive evolution of the early-type population with a formation redshift of z_form = 2, the strengths of the 4000A break and scaling relations between metal line indices and velocity dispersion reject this model with high significance. By inverting SSP models for the Hbeta_G, Mgb, and <Fe> line indices, we calculate that, at a given velocity dispersion and metallicity, galaxies in RXJ0142.0+2131 have luminosity-weighted mean ages 0.14 +- 0.07 dex older than the low-redshift sample. We also find that [alpha/Fe] in stellar populations in RXJ0142.0+2131 is 0.14 +- 0.03 greater than at low redshift. All scaling relations are consistent with these estimated offsets. (abridged)
dc.descriptionAJ, accepted. 31 pages, 13 figures, uses emulateapj.cls. High-resolution figures available on request from first author
dc.identifierhttps://arxiv.org/abs/astro-ph/0504069
dc.identifierhttp://arxiv.org/abs/astro-ph/0504069
dc.identifierAstron.J.130:445-474,2005
dc.identifierdoi:10.1086/431745
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/196787
dc.subjectAstrophysics
dc.titleRXJ0142.0+2131: I. The galaxy content of an X-ray-luminous galaxy cluster at z=0.28
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