J/MNRAS/414/3052 HST/ACS Coma Cluster Survey. VI. (den Brok+, 2011)
The HST/ACS Coma cluster survey.
VI. Colour gradients in giant and dwarf early-type galaxies.
den Brok M., Peletier R.F., Valentijn E.A., Balcells M., Carter D.,
Erwin P., Ferguson H.C., Goudfrooij P., Graham A.W., Hammer D., Lucey J.R.,
Trentham N., Guzman R., Hoyos C., Verdoes Kleijn G., Jogee S., Karick A.M.,
Marinova I., Mouhcine M., Weinzirl T.
<Mon. Not. R. Astron. Soc., 414, 3052-3070 (2011)>
=2011MNRAS.414.3052D 2011MNRAS.414.3052D (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, photometry ; Photometry, HST ; Redshifts
Keywords: galaxies: clusters: individual: Coma - galaxies: dwarf -
galaxies: elliptical and lenticular, cD - galaxies: structure
Abstract:
Using deep, high-spatial-resolution imaging from the Hubble Space
Telescope/Advanced Camera for Surveys (HST/ACS) Coma Cluster Treasury
Survey, we determine colour profiles of early-type galaxies in the
Coma cluster. From 176 galaxies brighter than MF814W(AB)=-15mag
that are either spectroscopically confirmed members of Coma or
identified by eye as likely members from their low surface brightness,
data are provided for 142 early-type galaxies. Typically, colour
profiles are linear against log (R), sometimes with a nuclear region
of distinct, often bluer colour associated with nuclear clusters.
Colour gradients are determined for the regions outside the nuclear
components. We find that almost all colour gradients are negative,
both for elliptical and for lenticular galaxies. Most likely, earlier
studies that report positive colour gradients in dwarf galaxies are
affected by the bluer colours of the nuclear clusters, underlining
that high-resolution data are essential to disentangle the colour
properties of the different morphological components in galaxies.
Colour gradients of dwarf galaxies form a continuous sequence with
those of elliptical galaxies, becoming shallower towards fainter
magnitudes. Interpreting the colours as metallicity tracers, our data
suggest that dwarfs as well as giant early-type galaxies in the Coma
cluster are less metal rich in their outer parts. We do not find
evidence for environmental influence on the gradients, although we
note that most of our galaxies are found in the central regions of the
cluster. For a subset of galaxies with known morphological types, S0
galaxies have less steep gradients than elliptical galaxies.
Description:
We have used the data from the HST/ACS Coma Cluster Survey, a deep
two-passband imaging survey of the Coma cluster. A full description of
the observations and data reduction can be found in Paper I (Carter et
al., 2008ApJS..176..424C 2008ApJS..176..424C).
We have derived colour gradients for a sample of confirmed or very
likely Coma cluster members.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 83 142 Sample
tablea2.dat 66 34 Galaxies excluded from our sample
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See also:
J/ApJS/191/143 : HST/ACS Coma cluster survey. II. (Hammer+, 2010)
J/MNRAS/445/2385 : HST/ACS Coma Cluster Survey. X. (den Brok+, 2014)
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 25 A25 --- Name COMA ID (COMAiHHMMSS.ssspDDMMSS.SS,
[HVH2010] Comai JHHMMSS.sss+DDMMSS.ss in Simbad)
27- 35 F9.5 deg RAdeg Right ascension (J2000)
37- 44 F8.5 deg DEdeg Declination(J2000)
46- 50 F5.2 mag F814W Sersic F814W band magnitude
52 A1 --- Rating [0-2] Membership ratio (1)
54- 59 F6.4 --- z ?=- Redshift
61- 66 F6.3 --- Grad Colour gradient in the outer parts
68- 72 F5.3 --- e_Grad rms uncertainty on Gradient
74- 77 F4.2 --- eps Ellipticity used in the Galphot fit
79- 83 F5.2 -- chi2r Reduced chi2 from the fit of the gradient to
the outer part of the colour profile
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Note (1): Membership ratio as follows:
0 = spectroscopically confirmed members of Com
1 = almost certain member (sources that are only rarely found in the field)
2 = likely member
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Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 25 A25 --- Name COMA ID (COMAiHHMMSS.ssspDDMMSS.SS)
27- 66 A40 --- Reasons Reasons of exclusion of the sample
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
Carter et al., Paper I 2008ApJS..176..424C 2008ApJS..176..424C
Hammer et al., Paper II 2010ApJS..191..143H 2010ApJS..191..143H, Cat. J/ApJS/191/143
Hoyos et al., Paper III 2011MNRAS.411.2439H 2011MNRAS.411.2439H, Cat. J/MNRAS/411/2439
Peng et al., Paper IV 2011ApJ...730...23P 2011ApJ...730...23P
Price et al., Paper V 2009MNRAS.397.1816P 2009MNRAS.397.1816P
den Brok et al., Paper VI 2011MNRAS.414.3052D 2011MNRAS.414.3052D
Weinzirl et al., Paper VII 2014MNRAS.441.3083W 2014MNRAS.441.3083W
Marinova et al., Paper VIII 2012ApJ...746..136M 2012ApJ...746..136M
den Brok et al., Paper X 2014MNRAS.445.2385D 2014MNRAS.445.2385D, Cat. J/MNRAS/445/2385
(End) Patricia Vannier [CDS] 29-Jan-2018