J/ApJ/835/123 Globular clusters in NGC 474 from CFHT obs. (Lim+, 2017)
Globular clusters as tracers of fine structure in the dramatic shell galaxy
NGC 474.
Lim S., Peng E.W., Duc P.-A., Fensch J., Durrell P.R., Harris W.E.,
Cuillandre J.-C., Gwyn S., Lancon A., Sanchez-Janssen R.
<Astrophys. J., 835, 123-123 (2017)>
=2017ApJ...835..123L 2017ApJ...835..123L (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Photometry, ugriz ; Galaxies, nearby
Keywords: galaxies: elliptical and lenticular, cD; galaxies: evolution;
galaxies: formation; galaxies: individual: NGC 474;
galaxies: star clusters: general
Abstract:
Globular clusters (GCs) are some of the most visible tracers of the
merging and accretion histories of galaxy halos. Metal-poor GCs, in
particular, are thought to arrive in massive galaxies largely through
dry, minor merging events, but it is rare to see a direct connection
between GCs and visible stellar streams. NGC 474 is a post-merger
early-type galaxy with dramatic fine structures made of concentric
shells and radial streams that have been more clearly revealed by deep
imaging. We present a study of GCs in NGC 474 to better establish the
relationship between merger-induced fine structure and the GC system.
We find that many GCs are superimposed on visible streams and shells,
and about 35% of GCs outside 3Re,galaxy are located in regions of
fine structure. The spatial correlation between GCs and fine structure
is significant at the 99.9% level, which shows that this correlation
is not coincidental. The colors of GCs on fine structures are mostly
blue, and we also find an intermediate-color population that is
dominant in the central region and that will likely passively evolve
to have colors consistent with a traditional metal-rich GC population.
The association of the blue GCs with fine structures is direct
confirmation that many metal-poor GCs are accreted onto massive galaxy
halos through merging events and that the progenitors of these mergers
are sub-L* galaxies.
Description:
The observations were part of the Mass Assembly of Early-Type Galaxies
with Their Fine Structures (MATLAS; Duc+, 2015, J/MNRAS/446/120), a
Canada-France-Hawaii Telescope (CFHT) Large Program to obtain deep,
multiband optical imaging for 260 ATLAS3D galaxies (Cappellari+
2011, J/MNRAS/413/813) using MegaCam on CFHT. The accumulated exposure
times are 4900, 2415, 2415, and 3220s for u*, g', r', and i',
respectively.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 84 144 A catalog of the globular clusters in NGC 474
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See also:
B/cfht : Log of CFHT Exposures (CADC, 1979-)
J/ApJ/681/197 : ACS Virgo Cluster Survey. XV (Peng+, 2008)
J/MNRAS/413/813 : ATLAS3D project. I. (Cappellari+, 2011)
J/ApJ/773/L27 : GCs in ACSVCS early-type galaxies (Park+, 2013)
J/MNRAS/428/389 : SLUGGS GCs in early-type galaxies (Pota+, 2013)
J/MNRAS/446/120 : ATLAS3D project. XXIX (Duc+, 2015)
J/MNRAS/448/3484 : ATLAS3D Project. XXX (McDermid+, 2015)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- Seq Running sequence number
8 I1 h RAh [1] Hour of Right ascension (J2000)
10- 11 I2 min RAm [19/20] Minute of Right ascension (J2000)
13- 17 F5.2 s RAs Second of Right ascension (J2000)
19 A1 --- DE- [+] Sign of Declination (J2000)
20 I1 deg DEd [3] Degree of Declination (J2000)
22- 23 I2 arcmin DEm [19/29] Arcminute of Declination (J2000)
25- 28 F4.1 arcsec DEs Arcsecond of Declination (J2000)
30- 35 F6.3 mag gmag0 [18.9/25] The dereddened CFHT g-band AB magnitude
37- 42 F6.3 mag e_gmag0 [0.001/0.09] Uncertainty in gmag0
44- 49 F6.3 mag (u-g)0 [0.8/2] The dereddened (u-g) color index
51- 56 F6.3 mag e_(u-g)0 [0.002/0.5] Uncertainty in (u-g)0
58- 63 F6.3 mag (g-r)0 [0.2/1] The dereddened (g-r) color index
65- 70 F6.3 mag e_(g-r)0 [0.001/0.2] Uncertainty in (g-r)0
72- 77 F6.3 mag (g-i)0 [0.5/1.2] The dereddened (g-i) color index
79- 84 F6.3 mag e_(g-i)0 [0.001/0.2] Uncertainty in (g-i)0
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 16-Aug-2017