J/A+A/577/A59 g'i' photometry in 5 isolated elliptical galaxies (Salinas+, 2015)
Isolated ellipticals and their globular cluster systems.
III. NGC 2271, NGC 2865, NGC 3962, NGC 4240, and IC 4889.
Salinas R., Alabi A., Richtler T., Lane R.R.
<Astron. Astrophys. 577, A59 (2015)>
=2015A&A...577A..59S 2015A&A...577A..59S
ADC_Keywords: Galaxies, nearby ; Clusters, globular ; Photometry, SDSS
Keywords: galaxies: elliptical and lenticular, cD -
galaxies: star clusters: general - galaxies: structure
Abstract:
As tracers of star formation, galaxy assembly and mass distribution,
globular clusters have provided important clues to our understanding
of early-type galaxies. But their study has been mostly constrained to
galaxy groups and clusters where early-type galaxies dominate, leaving
the properties of the globular cluster systems (GCSs) of isolated
ellipticals as a mostly uncharted territory. We present
Gemini-South/GMOS g'i' observations of five isolated elliptical
galaxies: NGC 3962, NGC 2865, IC 4889, NGC 2271 and NGC 4240.
Photometry of their GCSs reveals clear color bimodality in three of
them, remaining inconclusive for the other two. All the studied GCSs
are rather poor with a mean specific frequency SN∼1.5, independently
of the parent galaxy luminosity. Considering also previous work, it is
clear that bimodality and especially the presence of a significant,
even dominant, population of blue clusters occurs at even the most
isolated systems, casting doubts on a possible accreted origin of
metal-poor clusters as suggested by some models. Additionally, we
discuss the possible existence of ultra-compact dwarfs around the
isolated elliptical NGC 3962.
Description:
We present a catalog of globular cluster candidates around the
isolated elliptical galaxies NGC 2271, NGC 2865, NGC 3962, NGC 4240,
and IC 4889. Besides being point sources, these are limited in color
and magnitude as explained in the paper. The catalog contains
equatorial coordinates as well as SDSS g and i magnitudes with
uncertainties.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 91 5 Basic data of the galaxies presented in this work
and observation dates
phot.dat 60 2180 Object positions and photometry
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Galaxy name
10- 11 I2 h RAh Right ascension (J2000)
13- 14 I2 min RAm Right ascension (J2000)
16- 19 F4.1 s RAs Right ascension (J2000)
21 A1 --- DE- Declination sign (J2000)
22- 23 I2 deg DEd Declination (J2000)
25- 26 I2 arcmin DEm Declination (J2000)
28- 31 F4.1 arcsec DEs Declination (J2000)
33- 40 A8 --- MType Morphological type (1)
41- 45 F5.2 mag BT0 [11.5/14.1] Total apparent B magnitude (2)
47- 51 F5.2 mag MOD [32/33] Distance modulus (m-M)0 (3)
52 A1 --- u_MOD [a] a: considered as uncertain by
Tonry et al. (2001ApJ...546..681T 2001ApJ...546..681T)
54- 59 F6.2 mag BMAG [-21.2/-18.0] Absolute B magnitude
61- 64 F4.1 kpc fov [41/61] Physical size covered by the GMOS
Field of View at each galaxy's distance
66- 75 A10 "date" Obs1 First observation date
77- 86 A10 "date" Obs2 Second observation date
87- 91 A5 --- Gal Abbreviated galaxy name, as in table phot.dat
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Note (1): Classification type comes from NED and HyperLeda databases
Note (2): Total apparent B magnitudes are taken from RC3 (Cat. VII/155/),
except for NGC 4240, taken from HyperLeda.
Note (3): Distance moduli have been adopted from Tonry et al.
(2001ApJ...546..681T 2001ApJ...546..681T), except the one for NGC 4240 which comes from
Reda et al. (2004MNRAS.354..851R 2004MNRAS.354..851R).
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Byte-by-byte Description of file: phot.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- Gal Galaxy ID
7- 9 I3 --- Seq [0/687] Object sequential number within
the galaxy
11- 12 I2 h RAh Right ascension (J2000.0)
14- 15 I2 min RAm Right ascension (J2000.0)
17- 21 F5.2 s RAs Right ascension (J2000.0)
23 A1 --- DE- Declination sign (J2000.0)
24- 25 I2 deg DEd Declination (J2000.0)
27- 28 I2 arcmin DEm Declination (J2000.0)
30- 34 F5.2 arcsec DEs Declination (J2000.0)
36- 41 F6.3 mag gmag [21.3/27.0] SDSS g magnitude
43- 47 F5.3 mag e_gmag [0.003/0.23] SDSS g magnitude error
49- 54 F6.3 mag imag [20.5/26.0] SDSS i magnitude
56- 60 F5.3 mag e_imag [0.004/0.22] SDSS i magnitude error
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Acknowledgements:
Ricardo Salinas, rsalinas(at)pa.msu.edu
References:
Lane et al., Paper I 2013A&A...549A.148L 2013A&A...549A.148L
Richtler et al., Paper II 2015A&A...574A..21R 2015A&A...574A..21R
(End) Patricia Vannier [CDS] 05-Mar-2015