scholarly journals An HST Survey of Cores of Early-Type Galaxies

1996 ◽  
Vol 171 ◽  
pp. 105-116 ◽  
Author(s):  
John Kormendy ◽  
Yong-Ik Byun ◽  
E. A. Ajhar ◽  
Tod R. Lauer ◽  
Alan Dressler ◽  
...  
Keyword(s):  
Outer Surface ◽  
Surface Brightness ◽  
Hubble Space Telescope ◽  
Elliptical Galaxies ◽  
Core Radius ◽  
Early Type ◽  
Late Type ◽  
Fundamental Plane ◽  
The Core ◽  
Oblate Spheroidal

Photometry of the central parts of bulges and elliptical galaxies with the Hubble Space Telescope (HST) confirms and extends ground-based results. Most giant ellipticals have cuspy cores: at the “break radius” rb (formerly the core radius rc), the steep outer surface brightness profile turns down to a shallow inner power law I(r) ∝ r–γ, 0 ≤ γ ≲ 0.25. The corresponding slope of the deprojected profile is derived; the flattest cores allow box orbits to survive. Cores continue to satisfy fundamental plane parameter correlations like those found from the ground. In particular, HST confirms that the luminosity sequence of elliptical galaxies (from cDs to M 32) is physically unrelated to spheroidal galaxies like Fornax. The latter are closely related to late-type dwarfs. Low-luminosity ellipticals do not show cores: 0.5 ≲ γ ≲ 1.3. The most important new result is that global and core properties both show signs of a dichotomy between (i) low-luminosity ellipticals that rotate rapidly, that are nearly isotropic and oblate-spheroidal, that have disky-distorted isophotes, and that are coreless and (ii) giant ellipticals that are essentially nonrotating, anisotropic, and moderately triaxial, that are boxy-distorted, and that have cuspy cores.

scholarly journals Kinematic properties and dark matter fraction of Virgo dwarf early-type galaxies

2012 ◽  
Vol 10 (H16) ◽  
pp. 335-335
Author(s):  
E. Toloba ◽  
A. Boselli ◽  
R. Peletier ◽  
J. Gorgas
Keyword(s):  
Dark Matter ◽  
Galaxy Evolution ◽  
Dwarf Galaxies ◽  
Elliptical Galaxies ◽  
Virgo Cluster ◽  
Early Type ◽  
Late Type ◽  
Fundamental Plane ◽  
Ram Pressure ◽  
Kinematic Properties

AbstractWhat happens to dwarf galaxies as they enter the cluster potential well is one of the main unknowns in studies of galaxy evolution. Several evidence suggests that late-type galaxies enter the cluster and are transformed to dwarf early-type galaxies (dEs). We study the Virgo cluster to understand which mechanisms are involved in this transformation. We find that the dEs in the outer parts of Virgo have rotation curves with shapes and amplitudes similar to late-type galaxies of the same luminosity (Fig. 1). These dEs are rotationally supported, have disky isophotes, and younger ages than those dEs in the center of Virgo, which are pressure supported, often have boxy isophotes and are older (Fig. 1). Ram pressure stripping, thus, explains the properties of the dEs located in the outskirts of Virgo. However, the dEs in the central cluster regions, which have lost their angular momentum, must have suffered a more violent transformation. A combination of ram pressure stripping and harassment is not enough to remove the rotation and the spiral/disky structures of these galaxies. We find that on the the Faber-Jackson and the Fundamental Plane relations dEs deviate from the trends of massive elliptical galaxies towards the position of dark matter dominated systems such as the dwarf spheroidal satellites of the Milky Way and M31. Both, rotationally and pressure supported dEs, however, populate the same region in these diagrams. This indicates that dEs have a non-negligible dark matter fraction within their half light radius.

scholarly journals Fundamental Plane and Merger Scenario

1999 ◽  
Vol 186 ◽  
pp. 185-188
Author(s):  
K. Bekki
Keyword(s):  
Surface Brightness ◽  
Velocity Dispersion ◽  
Evolutionary Process ◽  
Elliptical Galaxies ◽  
Scaling Relation ◽  
Early Type ◽  
Dynamical Mass ◽  
Fundamental Plane ◽  
Apparent Deviation ◽  
The Mean

The Fundamental Plane (FP) is one of the most important universal relations in early type galaxies because it contains valuable information about the formative and evolutionary process of galaxies (Djorgovski & Davis 1987, Dressler et al. 1987). The commonly used form of the scaling relation in the FP is described as Re = σAIB, where Re, σ, and I are effective radius, central velocity dispersion, and mean surface brightness of elliptical galaxies, respectively. The exponents A, B are considered to be 1.56 ± 0.07 and −0.94 ± 0.09 in the FP derived by K band photometry, respectively, and these values deviate significantly from the values A = 2.0 and B = −1.0 expected from virial theorem (Pahre et al. 1995; Djorgovski, Pahre, & de Carvalho 1996). This apparent deviation requires that the ratio of dynamical mass (M) to luminosity of elliptical galaxies (L) depends on M as M/L ∝ Mα (α = 0.12 ± 0.03 for K band). Possible interpretations for the required dependence of M/L on M are generally considered to be divided into the following two. One is that the required dependence of M/L on M results from the fact that the mean stellar age and metalicity of elliptical galaxies depend systematically on M. The other is that the required dependence reflects the M dependence of structural and kinematical properties of elliptical galaxies (“nonhomology”). Although we should not neglect the importance of stellar populations in generating the M dependence of the M/L (Renzini & Ciotti 1993), we here consider that the origin of the required M dependence of M/L is closely associated with the structural and kinematical properties dependent on M or L in elliptical galaxies.

scholarly journals Stellar Populations of the Most Massive Galaxies

2009 ◽  
Vol 5 (S267) ◽  
pp. 459-459
Author(s):  
Alexander Fritz ◽  
Michael D. Hoenig ◽  
Ricardo P. Schiavon
Keyword(s):  
High Velocity ◽  
Surface Brightness ◽  
Stellar Populations ◽  
Spectroscopic Properties ◽  
Low Density ◽  
Early Type ◽  
Small Surface ◽  
Fundamental Plane ◽  
Massive Galaxies ◽  
Bona Fide

Within the hierarchical CDM framework, gas-poor mergers contribute substantially to the building of the most massive galaxies (Faber et al. 2007). We want to test this scenario by studying the fundamental plane (FP) and the stellar populations of the most massive galaxies. We investigate a well-defined sample of massive early-type galaxies at 0.1<z<0.4, identified from the SDSS database. Out of 42,000 possible targets in the SDSS database, we extracted 23 luminous early-type galaxies with bona fide high velocity dispersions of σ>350 km s−1. These systems are located either in high or low-density environments and show a variety of small surface-brightness structure. Using archival HST/ACS images and Gemini/GMOS spectroscopy, we will explore the photometric and spectroscopic properties of these galaxies.

scholarly journals The Manifold of Elliptical Galaxies

1987 ◽  
Vol 127 ◽  
pp. 79-88
Author(s):  
S. Djorgovski
Keyword(s):  
Galaxy Formation ◽  
Surface Brightness ◽  
Velocity Dispersion ◽  
Elliptical Galaxies ◽  
Morphological Parameters ◽  
Strong Regularity ◽  
Fundamental Plane ◽  
Global Properties ◽  
Error Bars ◽  
Intrinsic Scatter

Global properties of elliptical galaxies, such as the luminosity, radius, projected velocity dispersion, projected luminosity density, etc., form a two-dimensional family. This “fundamental plane” of elliptical galaxies can be defined by the velocity dispersion and mean surface brightness, and its thickness is presently given by the measurement error-bars only. This is indicative of a strong regularity in the process of galaxy formation. However, all morphological parameters which describe the shape of the distribution of light, and reflect dynamical anisotropies of stars, are completely independent from each other, and independent of the fundamental plane. The M/L ratios show only a small intrinsic scatter in a luminosity range spanning some four orders of magnitude; this suggests a constant fraction of the dark matter contribution in elliptical galaxies.

scholarly journals Near-infrared surface brightness fluctuation measurements with the Hubble Space Telescope's WFC3/IR channel

2012 ◽  
Vol 8 (S289) ◽  
pp. 371-374
Author(s):  
Hyejeon Cho ◽  
Joseph B. Jensen ◽  
John P. Blakeslee ◽  
Brigham S. French ◽  
Hyun-chul Lee ◽  
...  
Keyword(s):  
Surface Brightness ◽  
Near Infrared ◽  
Hubble Space Telescope ◽  
Wide Field ◽  
Population Synthesis ◽  
Early Type ◽  
Distance Method ◽  
Brightness Fluctuation ◽  
Advanced Camera For Surveys ◽  
Fornax Cluster

AbstractThe surface brightness fluctuation (SBF) method at near-infrared (NIR) wavelengths is a powerful tool for estimating distances to unresolved stellar systems with high precision. The IR channel of the Wide Field Camera 3 (WFC3), installed on board the Hubble Space Telescope (HST) in 2009, has a greater sensitivity and a wider field of view than the previous generation of HST IR instruments, making it much more efficient for measuring distances to early-type galaxies in the Local Volume. To take full advantage of its capabilities, we need to empirically calibrate the SBF distance method for WFC3's NIR passbands. We present the SBF measurements for the WFC3/IR F160W bandpass filter using observations of 16 early-type galaxies in the Fornax and Virgo Clusters. These have been combined with existing (g475–z850) color measurements from the Advanced Camera for Surveys Virgo and Fornax Cluster Surveys to derive a space-based H160-band SBF relation as a function of color. We have also compared the absolute SBF magnitudes to those predicted by evolutionary population synthesis models in order to study stellar population properties in the target galaxies.

scholarly journals Caught in the Act: the identification of the galaxies responsible for the faint blue excess

1996 ◽  
Vol 171 ◽  
pp. 221-224
Author(s):  
Simon P. Driver ◽  
Rogier A. Windhorst ◽  
Richard E. Griffiths
Keyword(s):  
Hubble Space Telescope ◽  
Early Type ◽  
Late Type ◽  
Space Telescope ◽  
Normal Galaxies ◽  
Number Counts

We summarise recent Hubble Space Telescope results on the morphology of faint field galaxies. Our two principle results are: (1) the galaxies responsible for the faint blue excess have late-type/irregular morphology and (2) the number counts of normal galaxies, ellipticals and early-type spirals, are well fit by standard no-evolution models implying that the giant population was in place and mature by a redshift of ≥ 0.7.

scholarly journals UV-IR color profiles of the outer regions of 2K nearby S4G galaxies

2016 ◽  
Vol 11 (S321) ◽  
pp. 257-259
Author(s):  
Alexandre Y. K. Bouquin ◽  
Armando Gil de Paz
Keyword(s):  
Surface Brightness ◽  
Large Fraction ◽  
Early Type ◽  
Late Type ◽  
Quenching Mechanism ◽  
Star Forming ◽  
Spatially Resolved ◽  
Ram Pressure ◽  
Late Type Star ◽  
Radial Evolution

AbstractWe present our new, spatially-resolved, photometry in FUV and NUV from images obtained by GALEX, and IRAC1 (3.6 μm) photometry obtained by the Spitzer Space Telescope. We analyzed the surface brightness profiles μFUV, μNUV, μ[3.6], as well as the radial evolution of the (FUV-NUV), (FUV - [3.6]), and (NUV - [3.6]) colors in the Spitzer Survey of Stellar Structures in Galaxies (S4G) galaxies (d < 40 Mpc) sample. We defined the GALEX Blue Sequence (GBS) and GALEX Red Sequence (GBR) from the (FUV - NUV) versus (NUV - [3.6]) color-color diagram, populated by late-type star forming galaxies and quiescent early-type galaxies respectively. While most disk becomes radially bluer for GBS galaxies, and stay constant for GRS galaxies, a large fraction ( > 50%) of intermediary GALEX Green Valley (GGV) galaxies’ outer disks are becoming redder. An outside-in quenching mechanism such as environmentally-related mechanisms such as starvation or ram-pressure-stripping could explain our results.

scholarly journals A framework for measuring weak-lensing magnification using the Fundamental Plane

2020 ◽  
Vol 496 (3) ◽  
pp. 2998-3014
Author(s):  
Jenna K C Freudenburg ◽  
Eric M Huff ◽  
Christopher M Hirata
Keyword(s):  
Surface Brightness ◽  
Cosmological Parameters ◽  
Elliptical Galaxies ◽  
Weak Lensing ◽  
Selection Function ◽  
Source Population ◽  
Fundamental Plane ◽  
Background Population ◽  
Number Counts ◽  
Better Than

ABSTRACT Galaxy–galaxy lensing is an essential tool for probing dark matter haloes and constraining cosmological parameters. While galaxy–galaxy lensing measurements usually rely on shear, weak-lensing magnification contains additional constraining information. Using the Fundamental Plane (FP) of elliptical galaxies to anchor the size distribution of a background population is one method that has been proposed for performing a magnification measurement. We present a formalism for using the FP residuals of elliptical galaxies to jointly estimate the foreground mass and background redshift errors for a stacked lens scenario. The FP residuals include information about weak-lensing magnification κ, and therefore foreground mass, since to first order, non-zero κ affects galaxy size but not other FP properties. We also present a modular, extensible code that implements the formalism using emulated galaxy catalogues of a photometric galaxy survey. We find that combining FP information with observed number counts of the source galaxies constrains mass and photo-z error parameters significantly better than an estimator that includes number counts only. In particular, the constraint on the mass is 17.0 per cent if FP residuals are included, as opposed to 27.7 per cent when only number counts are included. The effective size noise for a foreground lens of mass $M_\mathrm{ H}=10^{14}\, \mathrm{M}_\odot$, with a conservative selection function in size and surface brightness applied to the source population, is σκ, eff = 0.250. We discuss the improvements to our FP model necessary to make this formalism a practical companion to shear analyses in weak-lensing surveys.

scholarly journals Near-IR Imaging of Elliptical Galaxies

1995 ◽  
Vol 164 ◽  
pp. 443-443 ◽  
Author(s):  
M.A. Pahre ◽  
S. Djorgovski ◽  
K. Matthews ◽  
D. Shupe ◽  
R. De Carvalho ◽  
...  
Keyword(s):  
Surface Brightness ◽  
Stellar Population ◽  
Elliptical Galaxies ◽  
Virgo Cluster ◽  
Fundamental Plane ◽  
Near Ir ◽  
Surface Brightness Fluctuations ◽  
Distance Indicator ◽  
Color Gradients ◽  
Optical Color

We have imaged more than thirty early-type galaxies in the K-band to investigate their stellar populations. Our surface brightness fluctuations (SBF) measurements for the nearest 14 galaxies produce a mean fluctuations magnitude in the K-band of The scatter in the Virgo cluster is small at 0.18 mag, which implies that infrared SBF is potentially a good distance indicator (Pahre & Mould 1994). Inspection of the simple stellar population tracks of Worthey (1994) suggests that a plot of the fluctuation color against broadband color (V – I) might be useful in discriminating between age and metallicity effects in elliptical galaxies. We have measured (r – K) color gradients for the entire sample utilizing three methods, two of them independent of sky-subtraction errors, as found in Sparks & Jørgensen (1993). Our color gradients are consistent with a mean metallicity gradient of 0.14 mag dex−1, which is somewhat smaller than that implied by optical color and line gradients alone, suggesting that age gradients may also be important. Finally, we have constructed an infrared Fundamental Plane (FP) which is consistent with its optical counterpart; continued work will determine if there is a significant change in the tilt of the FP between the optical and infrared.

scholarly journals Formation of the largest galactic cores through binary scouring and gravitational wave recoil

2021 ◽  
Vol 502 (4) ◽  
pp. 4794-4814
Author(s):  
Imran Tariq Nasim ◽  
Alessia Gualandris ◽  
Justin I Read ◽  
Fabio Antonini ◽  
Walter Dehnen ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Surface Brightness ◽  
Elliptical Galaxies ◽  
Galactic Centre ◽  
Merging Galaxies ◽  
The Core ◽  
Major Merger ◽  
Minor Mergers ◽  
Light Profiles ◽  
Compact Cluster

ABSTRACT Massive elliptical galaxies are typically observed to have central cores in their projected radial light profiles. Such cores have long been thought to form through ‘binary scouring’ as supermassive black holes (SMBHs), brought in through mergers, form a hard binary and eject stars from the galactic centre. However, the most massive cores, like the $\sim 3{\, \mathrm{kpc}}$ core in A2261-BCG, remain challenging to explain in this way. In this paper, we run a suite of dry galaxy merger simulations to explore three different scenarios for central core formation in massive elliptical galaxies: ‘binary scouring’, ‘tidal deposition’, and ‘gravitational wave (GW) induced recoil’. Using the griffin code, we self-consistently model the stars, dark matter, and SMBHs in our merging galaxies, following the SMBH dynamics through to the formation of a hard binary. We find that we can only explain the large surface brightness core of A2261-BCG with a combination of a major merger that produces a small $\sim 1{\, \mathrm{kpc}}$ core through binary scouring, followed by the subsequent GW recoil of its SMBH that acts to grow the core size. Key predictions of this scenario are an offset SMBH surrounded by a compact cluster of bound stars and a non-divergent central density profile. We show that the bright ‘knots’ observed in the core region of A2261-BCG are best explained as stalled perturbers resulting from minor mergers, though the brightest may also represent ejected SMBHs surrounded by a stellar cloak of bound stars.

Sign in / Sign up

Export Citation Format

Share Document