Galaxy scaling relations from the ACS Virgo and Fornax Cluster Surveys: no evidence for a dwarf-giant dichotomy

AbstractWe examine the photometric and structural properties of early-type galaxies derived from the ACS Virgo and Fornax Cluster Surveys, supplementing these data with previously published or newly reanalysed data for additional early-type galaxies in Virgo, Fornax and the Local Group. As we have noted elsewhere, Sérsic models are found to provide accurate representations of the observed brightness profiles on scales greater than a few percent of the effective radius, Re. On smaller scales, the brightness profiles of bright (MB ≳ −20) galaxies show central deficits with respect to the inward extrapolation of the Sérsic models; fainter galaxies usually show central excesses. Fainter than MB ≈ −20, we find a continuity in the photometric and structural scaling relations: i.e., between absolute magnitude, central surface brightness, Sérsic index, effective radius, and the surface brightness measured at, and averaged within, the effective radius. There is no evidence for a “dwarf/giant dichotomy” — a conclusion consistent with a number of recent studies but contrary to some earlier claims.

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A Flat Faint End of the Fornax Cluster Galaxy Luminosity Function

Proceedings of the International Astronomical Union ◽

10.1017/s1743921307014172 ◽

2007 ◽

Vol 3 (S244) ◽

pp. 331-335 ◽

Cited By ~ 1

Author(s):

S. Mieske ◽

M. Hilker ◽

L. Infante ◽

C. Mendes de Oliveira

Keyword(s):

Surface Brightness ◽

Luminosity Function ◽

Local Group ◽

Dwarf Galaxy ◽

High Mass ◽

Wide Field ◽

Early Type ◽

Cluster Galaxy ◽

Fornax Cluster ◽

Galaxy Luminosity Function

AbstractWe analyse the photometric properties of the early-type Fornax cluster dwarf galaxy population (MV > −17 mag), based on a wide field imaging study of the central cluster area in V and I band-passes with IMACS/Magellan at Las Campanas Observatory. We create a fiducial sample of ~ 100 Fornax cluster dwarf ellipticals (dEs) with −16.6 < MV < −8.8 mag in the following three steps: (1) To verify cluster membership, we measured I-band surface brightness fluctuations (SBF) distances to candidate dEs known from previous surveys; (2) We re-assessed morphological classifications for those candidate dEs that are too faint for SBF detection; and (3) We searched for new candidate dEs in the size-luminosity regime close to the resolution limit of previous surveys. The resulting fiducial dE sample follows a well-defined surface brightness – magnitude relation, showing that Fornax dEs are about 40% larger than Local Group dEs. The sample also defines a colour-magnitude relation similar to that of Local Group dEs. The early-type dwarf galaxy luminosity function in Fornax has a very flat faint end slope α ≃ −1.1 ± 0.1. We compare the number of dwarfs per unit mass with those in other environments and find that the Fornax cluster fits well into a general trend of a lack of high-mass dwarfs in more massive environments.

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The structure of early-type galaxies from the ACS Virgo and Fornax cluster surveys: cores, nuclei and supermassive black holes

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308017651 ◽

2007 ◽

Vol 3 (S245) ◽

pp. 203-206

Author(s):

Laura Ferrarese ◽

Patrick Côté

Keyword(s):

Black Holes ◽

Surface Brightness ◽

Supermassive Black Holes ◽

Effective Radius ◽

Core Structure ◽

Host Galaxy ◽

Early Type ◽

The Core ◽

The Galaxy ◽

Fornax Cluster

AbstractThe core structure of early-type galaxies is revisited in light of recent results from the ACS Virgo and Fornax Cluster Surveys. These surveys are comprised of HST/ACS g, z band images for a representative sample of 143 early-type galaxies, spanning a factor 720 in B-band luminosity. The data indicates a clear transition in the core structure going from the brightest to the faintest galaxies. In contrast to previous claims, however, this transition is found to be a continuous function of galaxy magnitude. We characterize the core structure in terms of deviations of the observed surface brightness profile – measured within ~ 2% of the galaxy effective radius – relative to the inner extrapolation of the Sérsic law that best fits the profiles on larger scales. Virtually all galaxies fainter than MB ~ −20 mag contain distinct stellar nuclei, and are described by surface brightness profiles that lie above the Sérsic extrapolation, while the reverse is true for brighter galaxies. The latter are also known to host supermassive black holes. A relation between SBHs and stellar nuclei is suggested by the fact that both types of “central massive objects” contain the same fraction, 0.2% of the total mass of the host galaxy.

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Dwarf Elliptical Galaxies in the M81 Group: The Structure and Stellar Populations of BK5N and F8D1

Highlights of Astronomy ◽

10.1017/s1539299600020220 ◽

1998 ◽

Vol 11 (1) ◽

pp. 132-133

Author(s):

Taft E. Armandroff ◽

Nelson Caldwell ◽

G.S. Da Costa ◽

Patrick Seitzer

Keyword(s):

Surface Brightness ◽

Local Group ◽

Absolute Magnitude ◽

Groups Of Galaxies ◽

Central Surface ◽

Luminous Matter ◽

Total Magnitude ◽

Metal Abundance ◽

The Mean ◽

Red Giant

The M81 group is one of the nearest groups of galaxies, but its properties are quite different from those of the Local Group. It has therefore provided a different environment for the evolution of its member galaxies. We have carried out a CCD survey of the M81 group to search for analogs to Local Group dwarf elliptical (dE) galaxies. All the M81 dwarfs previously identified in photographic surveys were recovered and we also discovered several new systems whose surface brightnesses fall within the range found for Local Group dE’s. We have obtained HST WFPC2 images through the F555W and F814W filters of two M81 group dE’s: BK5N and a new system, designated F8D1. The resulting color-magnitude diagrams show the upper two magnitudes of the red giant branch. The I magnitudes of the red giant branch tip in both galaxies yield distances that are consistent with membership in the M81 group. Surface brightness and total magnitude measurements indicate that BK5N and F8D1 have similar central surface brightness (24.5 and 25.4 mag arcsec-2 in V, respectively), but F8D1 is larger length scale results in it being 3 magnitudes more luminous than BK5N. BK5N lies on the relation between central surface brightness and absolute magnitude defined by Local Group dwarf ellipticals, but F8D1 does not. F8D1 is more luminous for its central surface brightness than the relation predicts, similar to the large low surface brightness dwarf galaxies found in, for example, Virgo. The mean color of the giant branch is used to establish the mean abundance of each galaxy. F8D1, the more luminous galaxy, is significantly more metal rich ([Fe/H] ≈ -1.0) than BK5N ([Fe/H] ≈ -1.7). Both BK5N and F8D1 lie on the relation between absolute magnitude and metal abundance defined by Local Group dwarf ellipticals. However, as regards the relation between central surface brightness and metal abundance, BK5N again follows the Local Group dwarfs, while F8D1 deviates significantly from this relation. This suggests that the total amount of luminous matter is more fundamental in controlling metal enrichment than the surface density of luminous matter. We have also used the color width of the giant branch compared with the photometric errors to establish abundance ranges in both galaxies, the sizes of which are comparable to those in Local Group dE’s.

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

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312021734 ◽

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.

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The Centers of Early‐Type Galaxies withHubble Space Telescope. VI. Bimodal Central Surface Brightness Profiles

The Astrophysical Journal ◽

10.1086/519229 ◽

2007 ◽

Vol 664 (1) ◽

pp. 226-256 ◽

Cited By ~ 171

Author(s):

Tod R. Lauer ◽

Karl Gebhardt ◽

S. M. Faber ◽

Douglas Richstone ◽

Scott Tremaine ◽

...

Keyword(s):

Surface Brightness ◽

Early Type ◽

Space Telescope ◽

Central Surface

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The Fornax Deep Survey with the VST

Astronomy and Astrophysics ◽

10.1051/0004-6361/201833741 ◽

2019 ◽

Vol 623 ◽

pp. A1 ◽

Cited By ~ 16

Author(s):

E. Iodice ◽

M. Spavone ◽

M. Capaccioli ◽

R. F. Peletier ◽

G. van de Ven ◽

...

Keyword(s):

Globular Clusters ◽

Surface Brightness ◽

Major Axis ◽

Position Angle ◽

Early Type ◽

Semi Major Axis ◽

Cluster Galaxies ◽

The Galaxy ◽

Deep Survey ◽

Fornax Cluster

Context. This paper is based on the multi-band (ugri) Fornax Deep Survey (FDS) with the VLT Survey Telescope (VST). We study bright early-type galaxies (mB ≤ 15 mag) in the 9 square degrees around the core of the Fornax cluster, which covers the virial radius (Rvir ∼ 0.7 Mpc). Aims. The main goal of the present work is to provide an analysis of the light distribution for all galaxies out to unprecedented limits (in radius and surface brightness) and to release the main products resulting from this analysis in all FDS bands. We give an initial comprehensive view of the galaxy structure and evolution as a function of the cluster environment. Methods. From the isophote fit, we derived the azimuthally averaged surface brightness profiles, the position angle, and ellipticity profiles as a function of the semi-major axis. In each band, we derived the total magnitudes, effective radii, integrated colours, and stellar mass-to-light ratios. Results. The long integration times, the arcsec-level angular resolution of OmegaCam at VST, and the large covered area of FDS allow us to map the light and colour distributions out to large galactocentric distances (up to about 10−15 Re) and surface brightness levels beyond μr = 27 mag arcsec−2 (μB ≥ 28 mag arcsec−2). Therefore, the new FDS data allow us to explore in great detail the morphology and structure of cluster galaxies out to the region of the stellar halo. The analysis presented in this paper allows us to study how the structure of galaxies and the stellar population content vary with the distance from the cluster centre. In addition to the intra-cluster features detected in previous FDS works, we found a new faint filament between FCC 143 and FCC 147, suggesting an ongoing interaction. Conclusions. The observations suggest that the Fornax cluster is not completely relaxed inside the virial radius. The bulk of the gravitational interactions between galaxies happens in the W-NW core region of the cluster, where most of the bright early-type galaxies are located and where the intra-cluster baryons (diffuse light and globular clusters) are found. We suggest that the W-NW sub-clump of galaxies results from an infalling group onto the cluster, which has modified the structure of the galaxy outskirts (making asymmetric stellar halos) and has produced the intra-cluster baryons (ICL and GCs), concentrated in this region of the cluster.

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Discovery of new dwarf galaxies around NGC4631 with Subaru/Hyper Suprime-Cam

Proceedings of the International Astronomical Union ◽

10.1017/s1743921315007115 ◽

2015 ◽

Vol 11 (S317) ◽

pp. 350-351

Author(s):

Mikito Tanaka ◽

Masashi Chiba ◽

Yutaka Komiyama

Keyword(s):

Local Group ◽

Dwarf Galaxies ◽

Dwarf Galaxy ◽

Outer Region ◽

Absolute Magnitude ◽

Effective Radius ◽

The Other ◽

Interacting Galaxies ◽

Irregular Galaxy ◽

Star Forming

AbstractWe have observed on-going interacting galaxies (NGC4631 and NGC4656) using Subaru/Hyper Suprime-Cam and reduced the data using HSC pipeline and conducted photometry based on DAOphot. Then, we have detected 8 new dwarf galaxy candidates in the outer region of NGC4631 and confirmed the three candidates previously reported by Karachentsev et al. 2014. The 3 or 4 candidates detected in this study may be a star-forming dwarf irregular galaxy and the other 7 candidates may be an old dwarf spheroidal galaxy based on these stellar populations. It looks like that the effective radius - absolute magnitude relation of dwarf galaxies in NGC4631 group is similar to the relation of the Local Group and the other galaxy systems.

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Applying galactic archeology to massive galaxies using deep imaging surveys

Proceedings of the International Astronomical Union ◽

10.1017/s1743921315003518 ◽

2014 ◽

Vol 10 (S311) ◽

pp. 120-125

Author(s):

Pierre-Alain Duc

Keyword(s):

Galaxy Evolution ◽

Surface Brightness ◽

Local Group ◽

Diffuse Light ◽

Early Type ◽

Massive Galaxies ◽

Systematic Survey ◽

Deep Imaging ◽

Low Surface Brightness ◽

Optical Surveys

AbstractVarious programs aimed at exploring the still largely unknown low surface brightness Universe with deep imaging optical surveys have recently started. They open a new window for studies of galaxy evolution, pushing the technique of galactic archeology outside the Local Group (LG). The method, based on the detection and analysis of the diffuse light emitted by collisional debris or extended stellar halos (rather than on stellar counts as done for LG systems), faces however a number of technical difficulties, like the contamination of the images by reflection halos and Galactic cirrus. I review here the on-going efforts to address them and highlight the preliminary promising results obtained with a systematic survey with MegaCam on the CFHT of nearby massive early-type galaxies done as part of the ATLAS3D, NGVS and MATLAS collaborations.

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The Early-Type Dwarf Galaxy Population of the Fornax Cluster

Proceedings of the International Astronomical Union ◽

10.1017/s1743921306006326 ◽

2006 ◽

Vol 2 (S235) ◽

pp. 226-226

Author(s):

Steffen Mieske

Keyword(s):

Surface Brightness ◽

Dwarf Galaxy ◽

Wide Field ◽

Early Type ◽

Cluster Membership ◽

Galaxy Population ◽

Fornax Cluster ◽

Galaxy Luminosity Function ◽

Field Imaging ◽

Wide Field Imaging

AbstractAIMS: We analyse the photometric properties of the early-type Fornax cluster dwarf galaxy population (MV> − 17 mag), based on a wide field imaging study of the central cluster area in V and I bandpasses. We used the instrument/telescope combination IMACS/Magellan at Las Campanas Observatory, providing much larger light collecting area and better image resolution than previous wide field imaging surveys.METHODS: We create a fiducial sample of Fornax cluster dwarf ellipticals (dEs) in the following three steps: (1) To verify cluster membership, we measured I-band surface brightness fluctuations (SBF) distances to candidate dEs known from previous surveys; (2) We re-assessed morphological classifications for those candidate dEs that are too faint for SBF detection; and (3) We searched for new candidate dEs in the size-luminosity regime close to the resolution limit of previous surveys.RESULTS: (1) We confirm cluster membership for 28 candidate dEs in the range −16.6 < MV < −10.1 mag by means of SBF measurement. We find no SBF background galaxy. (2) Of 51 further candidate dEs in the range −13.2 < MV < −8.6 mag, 2/3 are confirmed as probable cluster members by morphological re-assessment, while 1/3 are re-classified as probable background objects. (3) We find 12 new dE candidates in the range −12.3 < MV < −8.8 mag, two of which are directly confirmed via SBF measurement. The resulting fiducial dE sample follows a well-defined surface brightness – magnitude relation, showing that Fornax dEs are about 40% larger than Local Group dEs. The sample also defines a colour-magnitude relation that appears slightly shallower than that of Local Group dEs. The early-type dwarf galaxy luminosity function in Fornax has a very flat faint end slope α ≃ −1.1 ± 0.1. We discuss these findings in the context of structure formation theories.CONCLUSIONS: The SBF method is a very powerful tool to help constrain the faint end of the galaxy luminosity function in nearby galaxy clusters. For the Fornax cluster, morphological cluster memberships – if performed at sufficient resolution – are very reliable.This contribution is based on Mieske et al. (2006).

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