J/ApJ/939/74 Globular clusters from CFHT/MegaCam ugi obs. of M104 (Kang+, 2022)
Tracing the giant outer halo of the mysterious massive disk galaxy M104.
I. Photometry of the extended globular cluster systems.
Kang J., Lee M.G., Jang In S., Ko Y., Sohn J., Hwang N., Park B.-G.
<Astrophys. J., 939, 74 (2022)>
=2022ApJ...939...74K 2022ApJ...939...74K
ADC_Keywords: Galaxies, nearby; Clusters, globular; Photometry, ugriz; Colors
Keywords: Globular star clusters ; Early-type galaxies ; Elliptical galaxies ;
Galaxy evolution ; Lenticular galaxies
Abstract:
M104 (NGC 4594, the Sombrero galaxy) is a mysterious massive
early-type galaxy that shows a dominant bulge and a prominent disk.
However, the presence of a halo in M104 has been elusive, and it is
not yet known how M104 has acquired such a peculiar structure. Using
wide (∼2deg2) and deep ugi images of M104 obtained with the
CFHT/MegaCam, we detect a large number of globular clusters (GCs)
found out to R∼35' (∼100kpc). The color distribution of these GCs
shows two subpopulations: a blue (metal-poor) system and a red
(metal-rich) system. The total number of GCs is estimated to be
NGC=1610±30 and the specific frequency to be SN=1.8±0.1. The
radial number density profile of the GCs is steep in the inner region
at R<20' and becomes shallow in the outer region at 20'<R<35'. The
outer region is dominated by blue GCs and is extended out to R∼35'.
This shows clearly the existence of a giant metal-poor halo in M104.
The inner region is composed of a bulge hosting a disk, corresponding
to a metal-rich halo as seen in early-type galaxies. At least two
clumps of blue GCs are found in the outer region. One clump is
overlapped with a faint stellar stream located in the southwest,
indicating that it may be a remnant of a disrupted dwarf galaxy. Our
results imply that the metal-rich inner halo of M104 formed first via
major mergers, and the metal-poor outer halo grew via numerous minor
mergers.
Description:
We obtained wide and deep ugi images of M104 with CFHT/MegaCam as part
of the K-GMT Science Program (PI: Myung Gyoon Lee; PID: 15AK06) on
2015 May 17,24,25.
The CFHT is a 3.6m optical/infrared telescope located at Maunakea, and
the MegaCam is a wide-field imaging camera covering a 1x1° field
with a pixel scale of 0.185". We obtained seven, eight, and seven
shots, respectively, for the u, g, and i bands, so that the total
exposure times are about 2000, 4800, and 5600s.
We use the CFHT AB magnitude system in this study. See Section 2.3.
Objects:
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RA (ICRS) DE Designation(s)
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12 39 59.43 -11 37 22.9 M104 = NAME Sombrero Galaxy
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 60 2936 A ugi photometric catalog of the globular clusters
(GCs) in M104
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See also:
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
VII/195 : Globular Clusters in the Milky Way (Harris, 1996)
VII/202 : Globular Clusters in the Milky Way (Harris, 1997)
V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)
J/MNRAS/313/469 : Streaming motions of galaxy clusters. I. (Smith+, 2000)
J/MNRAS/327/1116 : VI photometry of Sombrero globular clusters (Larsen+, 2001)
J/MNRAS/365/1357 : Absolute mag. of Globular Cluster (Di Criscienzo+, 2006)
J/AJ/132/1593 : BVR phot. of NGC 4594 globular clusters (Spitler+, 2006)
J/ApJ/681/197 : ACS Virgo Cluster Survey. XV (Peng+, 2008)
J/ApJS/183/1 : Catalog of central stellar velocity dispersions (Ho+, 2009)
J/MNRAS/401/1965 : Globular clusters in M104 (Harris+, 2010)
J/MNRAS/412/2498 : Galaxy group & clouds in the local universe (Makarov+, 2011)
J/ApJ/772/82 : A catalog of globular cluster systems (Harris+, 2013)
J/ApJ/773/L27 : GCs in ACSVCS early-type galaxies (Park+, 2013)
J/AJ/147/150 : Velocities of globular clusters in M104 (Dowell+, 2014)
J/ApJS/217/32 : S4G galaxy morphologies in the CVRHS system (Buta+, 2015)
J/ApJ/835/123 : Globular clusters in NGC 474 from CFHT obs. (Lim+, 2017)
J/ApJ/872/202 : CFHT ugi photometry of globular clusters in M85 (Ko+, 2019)
J/ApJ/871/33 : BVI phot. catalog of star clusters in NGC4589 (Lee+, 2019)
J/ApJ/891/144 : CFHT dwarf satellite gal. around LV hosts (Carlsten+, 2020)
J/ApJ/899/140 : 632 Gaia Ultracompact Dwarf galaxy cand. (Voggel+, 2020)
J/ApJ/914/16 : NGC 5128 GCs from PISCes, Gaia DR2 and NSC (Hughes+, 2021)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Seq [1/2936] Running sequence number
6- 14 F9.5 deg RAdeg [189.4/190.6] Right Ascension (J2000)
16- 24 F9.5 deg DEdeg [-12.21/-11] Declination (J2000)
26- 30 F5.2 mag imag [18.1/24.9] CFHT/MegaCam apparent i-band AB
magnitude
32- 35 F4.2 mag e_imag [0.06/0.2] Uncertainty in imag
37- 40 F4.2 mag g-i [0.58/1.3] The (g-i) color index
42- 45 F4.2 mag e_g-i [0.08/0.4] Uncertainty in g-i
47- 50 F4.2 mag u-g [0.85/1.95] The (u-g) color index
52- 55 F4.2 mag e_u-g [0.14/3.2] Uncertainty in u-g
57- 60 F4.2 mag Ci [0.3/0.6] The i-band concentration index
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 10-Sep-2024