J/ApJ/866/12 VVV and DECaPS photometry of the GC Minni 22 (Minniti+, 2018)
Confirmation of a new metal-poor globular cluster in the Galactic Bulge.
Minniti D., Schlafly E.F., Palma T., Claria J.J., Hempel M.,
Alonso-Garcia J., Bica E., Bonatto C., Braga V.F., Clementini G.,
Garofalo A., Gomez M., Ivanov V.D., Lucas P.W., Pullen J., Saito R.K.,
Smith L.C.
<Astrophys. J., 866, 12 (2018)>
=2018ApJ...866...12M 2018ApJ...866...12M
ADC_Keywords: Photometry, ugriz; Photometry, infrared; Clusters, globular
Keywords: Galaxy: bulge ; Galaxy: evolution ; globular clusters: general ;
globular clusters: individual (Minni 22)
Abstract:
We use deep near-IR photometry of the VISTA Variables in the Via
Lactea (VVV) Survey and deep DECam Plane Survey (DECaPS) optical
photometry to confirm the physical reality of the candidate globular
cluster (GC) Minni 22, which is located in the Galactic bulge. This
object, which was detected as a high density region in our maps of
bulge red giants, is now confirmed as a real GC based on the optical
and near-IR color-magnitude diagrams. We also recover three known
fundamental mode (ab type) RR Lyrae stars within 2 arcmin of the
cluster center. The presence of RR Lyrae stars also seems to confirm
Minni 22 as a bonafide old and metal-poor GC. We estimate a cluster
reddening E(J-Ks)=0.6mag and determine its heliocentric distance
D=7.4±0.3kpc. The optical and near-IR color-magnitude diagrams
reveal well-defined red giant branches in all cases, including a red
giant branch bump at Ks=13.30±0.05mag. The comparison with
theoretical isochrones yields a mean metallicity of [Fe/H]=-1.3±0.3dex,
and age of t∼11.2Gyr. This is a good example of a new low-luminosity
(MV=-6.2mag) GC found in the central bulge of the Milky Way. After
discussing the different ways to confirm the existence of bulge GC
candidates, we find that one of the best methods is to use the CMDs
from the combination of the DECaPS+VVV photometries.
Description:
We use data from the VISTA Variables in the Via Lactea (VVV) Survey
(Minniti+ 2010NewA...15..433M 2010NewA...15..433M and Saito+ 2012, II/337) that were
acquired with the VIRCAM camera at the VISTA 4m telescope at the ESO
Paranal Observatory between years 2010 and 2016.
We also exploit the data obtained by the deep DECam Plane Survey
(DECaPS) Survey, which is a grizY-band optical survey of the southern
Galactic plane (Schlafly+ 2018ApJS..234...39S 2018ApJS..234...39S). This survey was
carried out using the Dark Energy Camera at the 4m telescope of the
Cerro Tololo Inter-American Observatory.
Objects:
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RA (ICRS) DE Designation(s)
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17 48 49 -33 03 03 Minni 22 = [MGA2017] 22
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 94 45358 The combined VVV-DECaPS multicolor photometry
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See also:
II/337 : VISTA Variables in the Via Lactea Survey DR1 (Saito+, 2012)
J/A+A/303/468 : Spectrospcopy, IR-photom. in GCs (Minniti, 1995)
J/MNRAS/351/1204 : IR Photometry of 10 Galactic GCs (Valenti+, 2004)
J/A+A/523/A48 : Gaia photometry (Jordi+, 2010)
J/MNRAS/402/1729 : JHK photometry of 36 Galactic GCs (Valenti+ 2010)
J/AJ/149/99 : VVV GCs. I. 2MASS-GC02, Terzan 10 (Alonso-Garcia+, 2015)
J/ApJ/807/127 : 70 RR Lyrae stars in the LMC bar (Muraveva+, 2015)
J/other/NewA/49.50 : New Variables in 3 Galactic open clusters (Palma+, 2016)
J/A+A/604/A120 : omega Cen RR Lyrae and SX Phoenicis stars (Navarrete+, 2017)
J/A+A/616/A10 : Open clusters GaiaDR2 HR diagrams (Gaia Collaboration, 2018)
http://decaps.skymaps.info/ : The DECam Plane Survey home page
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 12 F12.7 deg RAdeg [267/267.4] Right Ascension (J2000)
14- 24 F11.7 deg DEdeg [-33.2/-32.9] Declination (J2000)
26- 31 F6.3 mag Zmag [12.4/20.8]? VVV Survey Z band magnitude (1)
33- 38 F6.3 mag YmagV [12.6/20.3]? VVV Survey Y band magnitude (1)
40- 45 F6.3 mag Jmag [12.4/19.5]? VVV Survey J band magnitude (1)
47- 52 F6.3 mag Hmag [12/18.7]? VVV Survey H band magnitude (1)
54- 59 F6.3 mag Ksmag [11.4/18.1] VVV Survey Ks band magnitude
61- 66 F6.3 mag gmag [15/24.5]? DECaPS survey g band magnitude (1)
68- 73 F6.3 mag rmag [14.2/25.5]? DECaPS survey r band magnitude (1)
75- 80 F6.3 mag imag [13.8/27.3]? DECaPS survey i band magnitude (1)
82- 87 F6.3 mag zmag [13/25.5]? DECaPS survey z band magnitude (1)
89- 94 F6.3 mag YmagD [13.5/24.6]? DECaPS survey Y band magnitude (1)
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Note (1): A blank indicates an Infinite value.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 27-Sep-2019