The Luminosities, Sizes, and Velocity Dispersions of Brightest Cluster Galaxies: Implications for Formation History

By Mariangela Bernardi, Joseph B. Hyde, R. Sheth, C. Miller, Robert Nichol. 2006

190 citations recorded by the source corpus.

The size-luminosity relation of early-type brightest cluster galaxies (BCGs), Re ∝ L0.88, is steeper than that for the bulk of the early-type galaxy population, for which Re ∝ L0.68. This is true if quantities derived from either de Vaucouleurs or Sérsic fits to the surface brightness profiles are used. Contamination from an intracluster light component centered on the BCG, with parameters similar to what has been seen in some recent studies, is not able to account for this difference. In addition, although BCGs are hardly offset from the fundamental plane defined by the bulk of the early-type population, they show considerably smaller scatter. The larger than expected sizes of BCGs, and the increased homogeneity, are qualitatively consistent with models that seek to explain the colors of the most massive galaxies by invoking dry dissipationless mergers, since dissipation tends to reduce the sizes of galaxies, and wet mergers that result in star formation would tend to increase the scatter in luminosity at a fixed size and velocity dispersion. Furthermore, BCGs define the same g - r color-magnitude relation as the bulk of the early-type population. If BCGs formed from dry mergers, then BCG progenitors must have been red for their magnitudes, suggesting that they hosted older stellar populations than is typical for their luminosities. Our findings have two other consequences. First, the Re-L relation of the early-type galaxy population as a whole (i.e., normal plus BCG) exhibits some curvature: the most luminous galaxies tend to have larger sizes than is expected from the Re ∝ L0.68 scaling—some of this curvature must be a consequence of the fact that an increasing fraction of the most luminous galaxies are BCGs. The second consequence is suggested by the fact that, despite following a steeper size-luminosity relation, BCGs tend to define a tight relation between dynamical mass Reσ2/G and luminosity. Although this relation is slightly different than that defined by the bulk of the population, the fact that their sizes are large for their luminosities suggests that their velocity dispersions are small. We find that, indeed, BCGs define a shallower σ-L relation than the bulk of the early-type galaxy population. This shallower relation suggests that there may be a curvature in the correlation between black hole mass and velocity dispersion; simple extrapolation of a single power law M•-σ relation to large σ will underestimate M•.

Subfields: Astronomy and Astrophysics, Electrical and Electronic Engineering, Instrumentation

View Paper: https://www.semanticscholar.org/paper/bea6eeb4f745429e825ae91b181be33c0f1999b8

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Electrical and Electronic Engineering

In Instrumentation

Citations in the corpus

On the correlations between galaxy properties and supermassive black hole mass (2011, methodology): “The existence of such BHFP has important implications for the largest M• and resolves the apparent conflict between expected and measured values of M• for the outliers in both M•–σ e and M• − Mbulge relations (e.g. Bernardi et al. 2007b; Lauer et al. 2007).”
GALAXY CLUSTER BARYON FRACTIONS REVISITED (2013, methodology): “9 Multiple authors have pointed out that the SDSS magnitudes, such as those used by Zhang et al. (2011), are underestimates because of oversubtraction of the sky in crowded regions and for extended sources (Lauer et al. 2007; Bernardi et al. 2007; Hyde & Bernardi 2009).”
THE INITIAL MASS FUNCTION OF EARLY-TYPE GALAXIES (2010, unknown): “This may therefore be another indication that velocity dispersion and not luminosity is the main parameter controlling stellar populations, including the IMF (Bernardi et al. 2007; Graves et al. 2009).”
THE MBH–LSPHEROID RELATION AT HIGH AND LOW MASSES, THE QUADRATIC GROWTH OF BLACK HOLES, AND INTERMEDIATE-MASS BLACK HOLE CANDIDATES (2012, background): “18 At this time Bernardi et al. (2007) had speculated that there may instead be curvature in the Mbh–σ relation The Mbh–Lspheroid relation 17 ported that the average photometric bulge mass of barred galaxies is less than that of non-barred disc galaxies of similar total galaxy stellar mass (Aguerri…”
Intracluster stars in simulations with active galactic nucleus feedback (2010, methodology): “We obtain an appropriate scaling relation by combining an empirical relation between cluster mass and BCG luminosity (Popesso et al. 2007) with a relation between BCG luminosity and half-light radius re (Bernardi et al. 2007).”
Discriminating Between the Physical Processes that Drive Spheroid Size Evolution (2009, background): “…environments may have the largest radii for their mass – if so, these systems have evolved to ‘overshoot’ the median of the local size–mass relations, evolving by more like a factor of ∼10 in effective radius (Gallazzi et al. 2006; Bernardi et al. 2007; Graves, Faber & Schiavon 2009).”
On the prevalence of radio‐loud active galactic nuclei in brightest cluster galaxies: implications for AGN heating of cooling flows (2006, background): “The SDSS photometry systematically underestimates the luminosities of nearby large galaxies, particularly in cluster environments, because it overestimates the level of sky background (Lauer et al. 2006; Bernardi et al. 2007; von der Linden et al. 2007).”
REVISITING THE SCALING RELATIONS OF BLACK HOLE MASSES AND HOST GALAXY PROPERTIES (2012, background): “Saturation of the L − σ and M• − σ relations has been predicted from observations and simulations of the most massive galaxies (e.g., Boylan-Kolchin et al. 2006; Bernardi et al. 2007; Lauer et al. 2007a).”
Compact high-redshift galaxies are the cores of the most massive present-day spheroids (2009, background): “In fact, at a fixed stellar mass, ellipticals with older stellar populations appear to have the largest radii (Gallazzi et al. 2006; Bernardi et al. 2007; Graves, Faber & Schiavon 2009; van der Wel et al. 2009).”
Physical properties and environments of nearby galaxies (2009, background): “…(FP; Djorgovski & Davis 1987; Faber et al. 1987) — the tight relationship among r50, half-light surface brightness I50, and velocity dispersion σ. Bernardi et al. (2007) selected nearby early-types according to concentration, color and emission line strength and found that for a relationship…”
The massive end of the luminosity and stellar mass functions: Dependence on the fit to the light profile (2013, methodology): “On the other hand, the total light associated with the best-fit single Sersic or a two-component Sersic-bulge + exponential-disk model, is less-biased from its true value (e.g. Bernardi et al. 2007; Bernardi et al. 2013).”
The DEEP3 Galaxy Redshift Survey: the impact of environment on the size evolution of massive early-type galaxies at intermediate redshift (2011, background): “…brightest cluster galaxies (BCGs) in the local Universe find that BCGs tend to be larger than early types of comparable stellar mass in less-dense environs (e.g. Bernardi et al. 2007; Desroches et al. 2007; von der Linden et al. 2007; Liu et al. 2008, see also Boylan-Kolchin, Ma & Quataert 2006).”
The Hierarchical Build-Up of Massive Galaxies and the Intracluster Light since z = 1 (2007, background): “Definition of the BCG It has recently come to light that standard photometry in large galaxy surveys systematically underestimates BCG luminosities for several different reasons (Lauer et al. 2007; Bernardi et al. 2007).”
THE DENSITY PROFILES OF MASSIVE, RELAXED GALAXY CLUSTERS. II. SEPARATING LUMINOUS AND DARK MATTER IN CLUSTER CORES (2012, result): “This small variation is consistent with previous studies of BCGs as “standard candles” with uniform luminosities and colors (e.g., Sandage 1972; Postman & Lauer 1995; Collins & Mann 1998; Bernardi et al. 2007).”
THE GALAXY CONTENT OF SDSS CLUSTERS AND GROUPS (2007, background): “…profiles (Matthews et al. 1964; Tonry 1987; Schombert 1988; Gonzalez et al. 2000, 2003), larger size at fixed luminosity than other early types (Bernardi et al. 2007, and references therein) and may contain a larger fraction of dark matter than typical galaxies (e.g., Mandelbaum et al. 2006;…”
Black Holes in Pseudobulges and Spheroidals: A Change in the Black Hole-Bulge Scaling Relations at Low Mass (2008, background): “…from the fundamental plane of regular ellipticals and classical bulges; while saturates at 400 km s 1 (and correspondingly MBH 3 ; 109 M ), the luminosities and effective radii of brightest cluster galaxies continue to rise (e.g., Bernardi et al. 2007; Lauer et al. 2007b; Desroches et al. 2007).”
Stellar Mass—Halo Mass Relation and Star Formation Efficiency in High-Mass Halos (2014, background): “As shown by Lauer et al. (2007) and Bernardi et al. (2007), the main source of the bias is oversubtraction of background (see also He et al. 2013) that is estimated at radii that are too small for such luminous, extended galaxies in general, and BCGs in particular.”