J/A+A/609/A26 Galactic Center old stars distribution (Gallego-Cano+, 2018)
The distribution of old stars around the Milky Way's central black hole.
I. Star counts.
Gallego-Cano E., Schoedel R., Nogueras-Lara F., Gallego-Calvente A.T.,
Amaro-Seoane P., Baumgardt H.
<Astron. Astrophys. 609, A26 (2018)>
=2018A&A...609A..26G 2018A&A...609A..26G (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Stars, nearby ; Photometry, infrared
Keywords: galaxies: structure - Galaxy: center - Galaxy: structure -
infrared: stars
Abstract:
The existence of dynamically relaxed stellar density cusp in dense
clusters around massive black holes is a long-standing prediction of
stellar dynamics, but it has so far escaped unambiguous observational
confirmation. In this paper we revisit the problem of inferring the
innermost structure of the Milky Way's nuclear star cluster via star
counts, to clarify whether it displays a core or a cusp around the
central black hole. We use judiciously selected adaptive optics
assisted high angular resolution images obtained with the NACO
instrument at the ESO VLT. Through image stacking and improved PSF
fitting we push the completeness limit about one magnitude deeper than
in previous, comparable work. Crowding and extinction corrections are
derived and applied to the surface density estimates. Known young, and
therefore dynamically not relaxed stars, are excluded from the
analysis. Contrary to previous work, we analyse the stellar density in
well-defined magnitude ranges in order to be able to constrain stellar
masses and ages. We conclude that the observed density of the faintest
stars detectable with reasonable completeness at the Galactic Centre,
is consistent with the existence of a stellar cusp around the Milky
Way's central black hole, Sagittarius A*.
Description:
Photometric and astrometric parameters for the point source detections
in the central parsec in the Galactic Centre. As we described in the
manuscript, we work on four pointings which we do not combine to a
final mosaic to avoid distortion issues. We analyse those four
pointings in four different ways, applying different sets of
StarFinder parameters. Therefore we present 16 tables, one for each
pointing in the observations and StarFinder parameters.
We present the extinction and completeness-corrected stellar density
in three different magnitudes ranges. The tables are used to represent
Figure 9 in the paper.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
pointings.pdf 512 1287 Images of the four pointings analyzed
table1.dat 79 9237 *Galactic Centre stars. Pointing 1 and SF-set 1
table2.dat 79 7497 *Galactic Centre stars. Pointing 1 and SF-set 2
table3.dat 79 10551 *Galactic Centre stars. Pointing 1 and SF-set 3
table4.dat 79 8476 *Galactic Centre stars. Pointing 1 and SF-set 4
table5.dat 79 8201 *Galactic Centre stars. Pointing 2 and SF-set 1
table6.dat 79 6766 *Galactic Centre stars. Pointing 2 and SF-set 2
table7.dat 79 9321 *Galactic Centre stars. Pointing 2 and SF-set 3
table8.dat 79 7816 *Galactic Centre stars. Pointing 2 and SF-set 4
table9.dat 79 10023 *Galactic Centre stars. Pointing 3 and SF-set 1
table10.dat 79 8202 *Galactic Centre stars. Pointing 3 and SF-set 2
table11.dat 79 11217 *Galactic Centre stars. Pointing 3 and SF-set 3
table12.dat 79 9189 *Galactic Centre stars. Pointing 3 and SF-set 4
table13.dat 79 9457 *Galactic Centre stars. Pointing 4 and SF-set 1
table14.dat 79 7868 *Galactic Centre stars. Pointing 4 and SF-set 2
table15.dat 79 10698 *Galactic Centre stars. Pointing 4 and SF-set 3
table16.dat 79 8628 *Galactic Centre stars. Pointing 4 and SF-set 4
tablea1.dat 29 43 *Surface density for brighter stars
tablea2.dat 29 43 *Surface density for faint stars
tablea3.dat 29 43 *Surface density for fainter stars
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Note on table1.dat table5.dat table9.dat table13.dat: The StarFinder (SF)
parameter set 1 corresponds to min_correlation=0.80 and deblend=0 for all
the pointings.
Note on table2.dat table6.dat table10.dat table14.dat: The StarFinder (SF)
parameter set 2 corresponds to min_correlation=0.85 and deblend=0 for all
the pointings.
Note on table3.dat table7.dat table11.dat table15.dat: The StarFinder (SF)
parameter set 3 corresponds to min_correlation=0.85 and deblend=1 for all
the pointings.
Note on table4.dat table8.dat table12.dat table16.dat: The StarFinder (SF)
parameter set 4 corresponds to min_correlation=0.90 and deblend=1 for all
the pointings.
Note on tablea1.dat: Surface density for stars in the magnitude interval
12.5 ≤ Ks ≤ 16.0. We exclude all spectroscopically identified early-type,
i.e. young and massive, stars from our sample (using the data of Do et al.
(2009ApJ...703.1323D 2009ApJ...703.1323D, Cat. J/ApJ/703/1323)
Note on tablea2.dat: Surface density for stars in the magnitude interval
16.5 ≤ Ks ≤ 17.5. We exclude all spectroscopically identified early-type,
i.e. young and massive, stars from our sample (using the data of Do et al.
(2009ApJ...703.1323D 2009ApJ...703.1323D, Cat. J/ApJ/703/1323)
Note on tablea3.dat: Surface density for stars in the magnitude interval
17.5 ≤ Ks ≤ 18.5. We exclude all spectroscopically identified early-type,
i.e. young and massive, stars from our sample (using the data of Do et al.
(2009ApJ...703.1323D 2009ApJ...703.1323D, Cat. J/ApJ/703/1323)
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See also:
J/ApJ/703/1323 : Spectroscopy of stars in Galaxy's nuclear cluster (Do+ 2009)
J/A+A/511/A18 : NIR observations of stars near SgrA* (Schoedel+, 2010)
Byte-by-byte Description of file: table?.dat table1?.dat
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Bytes Format Units Label Explanations
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1- 7 F7.3 arcsec offX X position offset(increasing to the East) (1)
9- 15 F7.3 arcsec offY Y position offset (1)
17- 21 F5.3 arcsec e_offX Uncertainty on X position (2)
23- 27 F5.3 arcsec e_offY Uncertainty on Y position (2)
29- 34 F6.3 mag Ksmag Ks-band magnitude (3)
36- 40 F5.3 mag e_Ksmag Uncertainty on Ks-band magnitude (2)
42- 47 F6.3 mag Hmag ?=0 H-band magnitude (3)
49- 53 F5.3 mag e_Hmag ?=0 Uncertainty on H-band magnitude (2)
55- 59 F5.3 mag AK Extinction in the Ks band (4)
61- 65 F5.3 mag e_AK Uncertainty on extinction in the Ks band
67- 71 F5.3 % p Percentage reduction in observed stars(5)
73- 77 F5.3 mag comp Source detection completeness in the Ks-images
79 I1 --- ageFlag [0,1] Age Flag (0: old star, 1: young star) (6)
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Note (1): Offset is from Sagittarius A*:
tables 1-4 : Pointing 1: x0= 672 and y0=1448
tables 5-8 : Pointing 2: x0= 671 and y0= 431
tables 9-12 : Pointing 3: x0=1692 and y0= 425
tables 13-16 : Pointing 4: x0=1694 and y0=1446
Note (2): Uncertainties on positions and magnitudes are the formal
uncertainties from StarFinder.
Note (3): The photometry was calibrated with the stars IRS 16C, IRS 16NW, and
IRS 33N. See Schoedel et al. (2010A&A...511A..18S 2010A&A...511A..18S, Cat. J/A+A/511/A18)
Note (4): The extinction maps for each of the four pointings were created with
the same method as applied in Schoedel et al.
(2010A&A...511A..18S 2010A&A...511A..18S, Cat. J/A+A/511/A18)
Note (5): Correction factor that we apply to each detected star to correct the
individual stellar magnitudes for differential extinction by applying the
methodology of Chatzopoulos et al. (2015MNRAS.453..939C 2015MNRAS.453..939C)
Note (6): We use the list of spectroscopically identified young stars
from Do et al. (2009ApJ...703.1323D 2009ApJ...703.1323D, Cat. J/ApJ/703/1323)
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Byte-by-byte Description of file: tablea1.dat tablea2.dat tablea3.dat
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Bytes Format Units Label Explanations
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1- 9 F9.6 arcsec Rad Projected radius from Saggitarius A*
11- 19 F9.6 arcsec-2 Den Number stellar density for late-type stars
21- 29 F9.6 arcsec-2 e_Den Uncertainty on number stellar density
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Acknowledgements:
The research leading to these results has received funding from the
European Research Council under the European Union's Seventh Framework
Programme (FP7/2007-2013) / ERC grant agreement n [614922]. This
work is based on observations made with ESO Telescopes at the La Silla
Paranal Observatory under programmes IDs 183.B-0100 and 089.B-0162.
Eulalia Gallego Cano, lgc(at)iaa.es
(End) Eulalia Gallego Cano [IAA-CSIC, Spain], Patricia Vannier [CDS] 15-Sep-2017