J/ApJ/951/148 Subaru/MOIRCS NIR obs. of the GC region (Nishiyama+, 2023)
Search for young and intermediate-age stellar populations in the Galactic Center
with Subaru/MOIRCS and CO narrowband filters.
Nishiyama S., Funamoto N., Schodel R.
<Astrophys. J., 951, 148 (2023)>
=2023ApJ...951..148N 2023ApJ...951..148N
ADC_Keywords: Galactic center; Photometry, infrared; Extinction; Colors
Keywords: Galactic center ; Infrared photometry ; Narrow band photometry
Abstract:
Extinction toward the Galactic Center (GC) is extreme and limits
observations of its stars to the infrared. In addition, the extinction
varies on scales of arcseconds. It is therefore highly challenging to
distinguish between different stars photometrically and to identify
young, massive, or intermediate-age stars that can trace recent star
formation. Here we report the results of near-infrared imaging
observations of a 6.0'x3.3' region at the GC that encompasses the
northwest part of the nuclear star cluster and parts of the nuclear
stellar disk. We carried out the observations with the wide-field
camera MOIRCS of the Subaru Telescope, using three narrowband (NB)
filters. Two of the filters trace the stellar continuum, while we use
the third one to measure the strength of the CO absorption features
that are prominent in the spectra of cool giants, shallower in the
spectra of warmer stars, and absent in young massive stars. Thus, we
aim to distinguish between old late-type giants and young and
intermediate-age stars. We have found 131 candidates of young and
intermediate-age stars. The magnitude limit is ∼11.25 in the
extinction-corrected K-band magnitude. The contamination of the
candidates by old giants is estimated to be 26%. We show that our
method allows us to identify correctly four out of five
spectroscopically confirmed massive stars, and 68 of 75
spectroscopically confirmed cool stars (91%). Our results suggest that
imaging observations with a CO NB filter can be complementary to other
methods to identify massive stars in the GC.
Description:
We carried out imaging observations of the central region of our
Galaxy with the Multi-Object Infrared Camera and Spectrograph
(MOIRCS). MOIRCS is a NIR instrument of the Subaru 8.2m Telescope for
wide-field imaging and multiobject spectroscopy.
The data were obtained on 2014 June 22. The coordinate of the pointing
center was RAJ2000=17:45:30.80,DEJ2000=-28:58:28.33, northwest from SgrA*.
We used three NB filters: NB1657, K-continuum (NB225), and NB2315.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 114 131 Candidates of young and intermediate age
populations
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See also:
J/ApJ/589/225 : Chandra X-ray sources toward Galactic Center (Muno+, 2003)
J/A+A/457/637 : UBVJHK synthetic phot. of Galactic O stars (Martins+, 2006)
J/MNRAS/371/38 : X-ray observations of the Galaxy center (Wang+, 2006)
J/A+A/499/483 : NIR obs. of sources in galactic center (Buchholz+, 2009)
J/ApJ/703/30 : Counterparts to Chandra X-ray sources. I. (Mauerhan+, 2009)
J/ApJS/181/110 : Galactic center X-ray sources (Muno+, 2009)
J/A+A/511/A18 : NIR observations of stars near SgrA* (Schoedel+, 2010)
J/MNRAS/417/114 : HST/NICMOS Galactic Center survey catalogue (Dong+, 2011)
J/A+A/549/A57 : Young, massive star candidates in Sgr A* (Nishiyama+, 2013)
J/A+A/570/A2 : Sp. & radial velocities of nuclear stars (Feldmeier+, 2014)
J/ApJ/821/44 : Star motions in the nuclear cluster of the MW (Fritz+, 2016)
J/A+A/617/A65 : Stellar population of the Arches cluster (Clark+, 2018)
J/A+A/618/A2 : Quintuplet cluster updated stellar census (Clark+, 2018)
J/A+A/609/A26 : Galactic Center old stars distribution (Gallego-Cano+, 2018)
J/A+A/610/A83 : GALACTICNUCLEUS: JHKs imaging survey (Nogueras-Lara+, 2018)
J/A+A/623/A83 : Blue stragglers Wd1-27 and Wd1-30a spectra (Clark+, 2019)
J/A+A/631/A20 : GALACTICNUCLEUS imaging survey. II. (Nogueras-Lara+, 2019)
J/MNRAS/494/396 : Metallicity distribution in GC (Feldmeier-Krause+, 2020)
J/A+A/641/A102 : MW nuclear star cluster HKs photometry (Schoedel+, 2020)
J/ApJ/905/173 : Gal. center compact radio sources from JVLA (Zhao+, 2020)
J/A+A/649/A83 : Milky Way nuclear disk KMOS survey (Fritz+, 2021)
J/MNRAS/500/3213 : 2D kinematics of massive stars (Libralato+, 2021)
J/A+A/653/A133 : GALACTICNUCLEUS IV. (Nogueras-Lara+, 2021)
J/ApJ/930/16 : Massive YSOs in the GC. II. IRTF spectra (Jang+, 2022)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/131] Internal identifier
5- 13 F9.5 deg RAdeg [266.32/266.44] Right Ascension (J2000)
15- 23 F9.5 deg DEdeg [-29/-28.9] Declination (J2000)
25- 30 F6.3 mag Jmag [15.16/21.1]? J band magnitude (1)
32- 36 F5.3 mag e_Jmag [0.004/0.14]? Uncertainty in Jmag (1)
38- 43 F6.3 mag Hmag [12.55/17.18] H band magnitude (1)
45- 49 F5.3 mag e_Hmag [0.003/0.04] Uncertainty in Hmag (1)
51- 56 F6.3 mag Ksmag [10.11/14.88] Ks band magnitude (1)
58- 62 F5.3 mag e_Ksmag [0.003/0.05] Uncertainty in Ksmag (1)
64- 67 F4.2 mag AKs [1.39/3.13] Ks band interstellar
extinction; Section 3.2
69- 72 F4.2 mag NBcol [0.04/0.25] Subaru/MOIRCS corrected
(NB225-NB2315) color (2)
74- 77 F4.2 --- sigma [2/7.83] Deviation from the color of the RGB
stars (3)
79- 83 F5.1 arcsec SepSgrA [38.6/325.7] Distance from Sgr A*
85 I1 --- ch [1/2] Detector channel
87- 114 A28 --- Alias Source alias
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Note (1): From Nogureras-Lara+ 2019, J/A+A/631/A20
Note (2): After the extinction and color correction, see Section 3.2.
Note (3): Deviation from the extinction and color corrected mean
(NB225-NB2315) color of the RGB stars, see Section 3.3.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 22-Aug-2025