Do the stellar populations of the brightest two group galaxies depend on the magnitude gap?

Abstract

We investigate how the stellar populations of the inner regions of the first and the second brightest group galaxies (respectively BGGs and SBGGs) vary as a function of magnitude gap, using an SDSS-based sample of 550 groups with elliptical BGGs. The sample is complete in redshift, luminosity and for $\Delta {\mathcal{M}}_{12}$ up to 2.5 mag, and contains 59 large-gap groups (LGGs, with $\Delta {\mathcal{M}}_{12}>2.0$ mag). We determine ages, metallicities, and SFHs of BGGs and SBGGs using the STARLIGHT code with two different single stellar population models (which lead to important disagreements in SFHs), and also compute $[\alpha /\mathrm{Fe}]$ from spectral indices. After removing the dependence with galaxy velocity dispersion or with stellar mass, there is no correlation with magnitude gap of BGG ages, metallicities, $[\alpha /\mathrm{Fe}]$, and SFHs. The lack of trends of BGG SFHs with magnitude gap suggests that BGGs in LGGs have undergone more mergers than those in small-gap groups, but these mergers are either dry or occurred at very high redshift, which in either case would leave no detectable imprint in their spectra. We show that SBGGs in LGGs lie significantly closer to the BGGs (in projection) than galaxies with similar stellar masses in normal groups, which appears to be a sign of the earlier entry of the former into their groups. Nevertheless, the stellar population properties of the SBGGs in LGGs are compatible with those of the general population of galaxies with similar stellar masses residing in normal groups.

20 pages, 15 figures, published in MNRAS. Consolidated version with Erratum

References in corpus (20)

• Mass and environment as drivers of galaxy evolution in SDSS and zCOSMOS and the origin of the Schechter function
• UV Star Formation Rates in the Local Universe
• Astrophysics Source Code Library
• Galaxy Groups in the SDSS DR4: I. The Catalogue and Basic Properties
• Evolutionary Stellar Population Synthesis with MILES. Part I: The Base Models and a New Line Index System
• Galaxy Zoo 1 : Data Release of Morphological Classifications for nearly 900,000 galaxies
• Evolutionary stellar population synthesis with MILES - II. Scaled-solar and α-enhanced models
• Towards a Concordant Model of Halo Occupation Statistics
• Dependence of Galaxy Quenching on Halo Mass and Distance from its Centre
• Scaling relations in fossil galaxy groups
• The universal distribution of halo interlopers in projected phase space. Bias in galaxy cluster concentration and velocity anisotropy?
• The stellar accretion origin of stellar population gradients in massive galaxies at large radii
• The Mass Assembly of Fossil Groups of Galaxies in the Millennium Simulation
• Imprints of galaxy evolution on H ii regions Memory of the past uncovered by the CALIFA survey
• The central elliptical galaxy in fossil groups and formation of BCGs
• On the Nature of Fossil Galaxy Groups: Are they really fossils ?
• SPIDER X - Environmental effects in central and satellite early-type galaxies through the stellar fossil record
• Truncated Star Formation in Compact Groups of Galaxies: A Stellar Population Study
• Ultimate age-dating method for galaxy groups; clues from the Millennium Simulations
• The Overlooked Potential of Generalized Linear Models in Astronomy - I: Binomial Regression

Cited by in corpus (18)

• The Impact of Environment on the Stellar Mass - Halo Mass Relation
• The Observed Evolution of the Stellar Mass - Halo Mass Relation for Brightest Central Galaxies
• Are fossil groups early-forming galaxy systems?
• A finer view of the conditional galaxy luminosity function and magnitude-gap statistics
• The impact of the dynamical state of galaxy groups on the stellar populations of central galaxies
• The Impact of Environment on Late Time Evolution of the Stellar Mass - Halo Mass Relation
• Fossil group origins IX. Probing the formation of fossil galaxy groups with stellar population gradients of their central galaxies
• The frequency of very young galaxies in the local Universe: II. The view from SDSS spectra
• Merger history of central galaxies in Semi-Analytic Models of galaxy formation
• Group galaxy number density profiles far out: is the 'one-halo' term NFW out to $>10$ virial radii?
• The Puzzling Origin of Massive Compact Galaxies in MaNGA
• Using Strong Gravitational Lensing to Identify Fossil Group Progenitors
• UV upturn versus UV weak galaxies: differences and similarities of their stellar populations unveiled by a de-biased sample
• The properties and environment of very young galaxies in the local Universe
• Fossil group origins: VIII RXJ075243.6+455653 a transitionary fossil group
• Assembly Conformity of Structure Growth: Fossil versus Normal Groups of Galaxies
• No dependence of radio properties of brightest group galaxies on the luminosity gap
• UV bright red-sequence galaxies: a comparative study between UV upturn and UV weak systems