J/A+A/463/503 Early-type dwarf galaxies in Fornax cluster (Mieske+, 2007)
The early-type dwarf galaxy population in the Fornax cluster.
Mieske S., Hilker M., Infante L., Mendes de Oliveira C.
<Astron. Astrophys. 463, 503 (2007)>
=2007A&A...463..503M 2007A&A...463..503M
ADC_Keywords: Galaxies, photometry ; Photometry, CCD ; Photometry, surface
Keywords: galaxies: clusters: individual: Fornax cluster - galaxies: dwarf -
galaxies: fundamental parameters - techniques: photometric -
galaxies: luminosity function, mass function
Abstract:
We analyse the photometric properties of the early-type Fornax cluster
dwarf galaxy population, based on a wide field imaging study of the
central cluster area in V and I. We used the instrument/telescope
combination IMACS/Magellan at Las Campanas Observatory.
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 fluctuation (SBF) distances to
candidate dEs; (2) We re-assessed morphological classifications for
candidate dEs 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.
(1) We confirm cluster membership for 28 candidate dEs in the range
-16.6<MV←10.1mag by means of SBF distances. We find no SBF
background galaxy. (2) Of 51 further candidate dEs in the range
-13.2<MV←8.6mag, 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←8.8mag. The surface brightness-magnitude relation defined
by the resulting fiducial dE sample shows that Fornax dEs are about
40% larger than Local Group dEs. The Fornax dE sample furthermore
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 faint end slope alpha=-1.1± 0.1.
Description:
Total V-band magnitude, central V-band surface brightness, and V-I
colour is presented for a sample of 100 dwarf elliptical galaxy
candidates in the central Fornax cluster. We also give the cluster
membership flag assigned to each galaxy, based upon distance
measurements obtained with the SBF method and on morphological
assessment. For most of the sources, the photometric parameters are
derived from imaging with the IMACS instrument at the Magellan
telescope on Las Campanas Observatory. For some fainter sources the
photometric parameters were derived from imaging with the WFCCD camera
at the 2.5m du Pont telescope on Las Campanas Observatory. Those
sources are specifically indicated in the comments column of the
table.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 108 100 Photometric parameters for 100 dwarf galaxy
candidates in the Fornax cluster
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See also:
VII/180 : Galaxies in Fornax Cluster and five nearby groups (Ferguson+ 1990)
J/A+AS/134/59 : The central Fornax Cluster. I. Galaxy photometry (Hilker+ 1999)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Galaxy Name (1)
14- 16 F3.1 --- Memb Membership flag (2)
19- 23 F5.2 mag Vmag Apparent V-band magnitude
27- 30 F4.2 mag e_Vmag Error of V-band magnitude
34- 38 F5.2 mag/arcsec2 SuBrV Central surface brightness in V-band
42- 45 F4.2 mag/arcsec2 e_SuBrV Error of central surface brightness
48- 53 F6.3 mag V-I V-I colour index
57- 61 F5.3 mag e_V-I Error of V-I colour index
65- 66 I2 h RAh Right Ascension J2000 (hours)
68- 69 I2 min RAm Right Ascension J2000 (minutes)
71- 75 F5.2 s RAs Right Ascension J2000 (seconds)
79 A1 --- DE- Declination J2000 (sign)
80- 81 I2 deg DEd Declination J2000 (degrees)
83- 84 I2 arcmin DEm Declination J2000 (minutes)
86- 90 F5.2 arcsec DEs Declination J2000 (seconds)
94-108 A15 --- Notes Special notes for some galaxies (3)
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Note (1): Three different namings:
FCC xxx refers to sources already included in the Fornax Cluster
Catalog (Ferguson et al., 1990, Cat. VII/180)
WFLSBxxxx refers to sources detected in our WFCCD imaging campaign
(Hilker et al., 2003A&A...397L...9H 2003A&A...397L...9H)
IMxxxxxxxxxx refers to sources detected only in our IMACS imaging
campaign
Note (2): Membership flags are as follows:
1 = Membership confirmed by SBF distance measurement
2 = Probable member based on morphological assessment
3 = Probable background based on morphological assessment
4 = Unclear classification
Non-integer numbers denote intermediate classifications
Note (3): Explanation of the different symbols:
* = Photometry is derived from WFCCD images
(Hilker et al., 2003A&A...397L...9H 2003A&A...397L...9H)
** = Candidate was not imaged in the WFCCD data but is listed in
the FCC as likely members. The FCC number is also given.
*** = Listed in the FCC as likely background member and as GCF_1-44
in Hilker et al. (1999, Cat. J/A+AS/134/59).
The FCC number is also given.
+ = Candidate was detected in the IMACS imaging by visual inspection,
not by SExtractor.
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Acknowledgements:
Steffen Mieske, smieske(at)eso.org
(End) Steffen Mieske [ESO, Germany], Patricia Vannier [CDS] 15-Dec-2006