J/ApJ/932/L6 Young stars in the Galactic Center (von Fellenberg+, 2022)
The young stars in the Galactic Center.
von Fellenberg S.D., Gillessen S., Stadler J., Baubock M., Genzel R.,
de Zeeuw T., Pfuhl O., Amaro Seoane P., Drescher A., Eisenhauer F.,
Habibi M., Ott T., Widmann F., Young A.
<Astrophys. J., 932, L6 (2022)>
=2022ApJ...932L...6V 2022ApJ...932L...6V
ADC_Keywords: Galactic center; Spectra, infrared; Radial velocities;
Cross identifications
Keywords: Galactic center
Abstract:
We present a large ∼30"x30" spectroscopic survey of the Galactic
Center using the SINFONI IFU at the VLT. Combining observations of the
last two decades we compile spectra of over 2800 stars. Using the
Bracket-γ absorption lines, we identify 195 young stars,
extending the list of known young stars by 79. In order to explore the
angular momentum distribution of the young stars, we introduce an
isotropic cluster prior. This prior reproduces an isotropic cluster in
a mathematically exact way, which we test through numerical
simulations. We calculate the posterior angular momentum space as a
function of projected separation from Sgr A*. We find that the
observed young star distribution is substantially different from an
isotropic cluster. We identify the previously reported feature of the
clockwise disk and find that its angular momentum changes as a
function of separation from the black hole and thus confirm a warp of
the clockwise disk (p∼99.2%). At large separations, we discover three
prominent overdensities of the angular momentum. One overdensity has
been reported previously, the counterclockwise disk. The other two are
new. Determining the likely members of these structures, we find that
as many as 75% of stars can be associated with one of these features.
Stars belonging to the warped clockwise disk show a top-heavy K-band
luminosity function, while stars belonging to the larger separation
features do not. Our observations are in good agreement with the
predictions of simulations of in situ star formation and argue for the
common formation of these structures.
Description:
We compile spectroscopic Galactic Center (GC) observations spanning
almost two decades. Our observations consist of adaptive optics
(AO)-assisted SINFONI observations at the VLT, most of which are
obtained with the combined H+K band, with a pixel scale of 100mas. We
rereduce and analyze all GC SINFONI pointings. A considerable fraction
of these data were analyzed in previous publications
(e.g., Paumard+ 2006, J/ApJ/643/1011; Bartko+ 2009, J/ApJ/697/1741 and
2010ApJ...708..834B 2010ApJ...708..834B; Pfuhl+ 2011ApJ...741..108P 2011ApJ...741..108P and
2014ApJ...782..101P 2014ApJ...782..101P).
Furthermore, we analyze previously unpublished observations of the GC,
which were obtained as backup observations of the continuous
monitoring of the motions of the stars in the GC
(Gillessen+ 2009ApJ...692.1075G 2009ApJ...692.1075G and 2017, J/ApJ/837/30; Gravity Col.
2021A&A...647A..59G 2021A&A...647A..59G).
See Section 2.1.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table4.dat 108 36 Stars with determined orbital solutions;
see Section 2.4
table5.dat 125 159 Young stars without determined orbital solutions;
see Section 2.5
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See also:
J/ApJ/470/864 : JHKL photometry of the Galactic Center (Blum+, 1996)
J/ApJ/643/1011 : Early-type stars in the center of the Galaxy (Paumard+, 2006)
J/ApJ/697/1741 : Warped disks of YSOs in Galactic center (Bartko+, 2009)
J/ApJ/737/73 : Infrared extinction toward the Galactic Centre (Fritz+, 2011)
J/ApJ/764/154 : Stellar populations in the central 0.5pc. I. (Do+, 2013)
J/ApJ/783/131 : Kinematic of stars in Galactic center (Yelda+, 2014)
J/ApJ/808/106 : NIR spectroscopic obs. in the Galactic Center (Stostad+, 2015)
J/ApJ/830/17 : Gal. Center secondary IR astrometric standards (Boehle+, 2016)
J/ApJ/837/30 : 25yrs obs. of stellar orbits in the GC (Gillessen+, 2017)
J/A+A/609/A26 : Galactic Center old stars distribution (Gallego-Cano+, 2018)
J/A+A/612/A1 : H.E.S.S. Galactic Plane Survey (HESS+, 2018)
J/ApJ/896/100 : Kinematic structure of the Gal. Center S cluster (Ali+, 2020)
J/A+A/641/A102 : Milky Way nuclear star cluster HKs phot. (Schoedel+, 2020)
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- MPE MPE identifier (<[EG97] SNN> in Simbad
for IDs starting with "S")
6- 8 A3 --- [PGM2006] Paumard+ 2006, J/ApJ/643/1011 identifier
10- 14 A5 --- UCLA UCLA identifier (<[GKM98] SNN-NNN> in Simbad
for IDs starting with "S")
16- 19 F4.2 arcsec a [0.1/6.6] Semimajor axis
21 A1 --- lea Limit flag on e_a
23- 26 F4.2 arcsec e_a [0.01/1.7] a uncertainty
28- 31 F4.2 --- e [0.01/1] Eccentricity
33 A1 --- lee Limit flag on e_e
35- 38 F4.2 --- e_e [0.01/1.7] e uncertainty
40- 45 F6.2 deg i [22.9/147.3] Inclination
47- 50 F4.2 deg e_i [0.03/8.1] inc uncertainty
52- 57 F6.2 deg Omega [6.26/345] Position angle of the ascending
node Ω
59- 62 F4.2 deg e_Omega [0.03/3.1] Omega uncertainty
64- 69 F6.2 deg w [3.5/360] Longitude of the pericenter, ω
71- 74 F4.2 deg e_w [0.02/9.3] omega uncertainty
76- 82 F7.2 yr Per [16/6056] Orbital period
84 A1 --- l_Per Limit flag on Per
86- 92 F7.2 yr e_Per [0.01/2344] Per uncertainty
94- 100 F7.2 yr t0 [-878/4006] Epoch, t0
102 A1 --- let0 Limit flag on e_t0
104- 108 F5.2 yr e_t0 [0.01/75] t0 uncertainty
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Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq [0/158] Running sequence number
5- 9 I5 --- T08 [-1/10007] Trippe+ (2008A&A...492..419T 2008A&A...492..419T)
identifier
11- 13 A3 [-] [PGM2006] Paumard+ 2006, J/ApJ/643/1011 identifier
15- 21 A7 --- UCLA UCLA identifier (<[GKM98] SNN-NNN> in Simbad)
23- 34 A12 --- ONames Alternative name (s)
36- 39 F4.1 mag Kmag [9.2/18] K band magnitude
41- 44 F4.1 arcsec Rad [0.4/29] Radius, R
46- 54 A9 --- Source Source vLSR (1)
56- 64 F9.5 arcsec offRA [-11/21.7] Right ascension offset in arcsec
66- 71 F6.2 mas e_offRA [0.05/409] offRA uncertainty
73- 81 F9.5 arcsec offDE [-11.3/22] Declination offset in arcsec
83- 88 F6.2 mas e_offDE [0.04/308] offDE uncertainty
90- 95 F6.1 km/s Vra [-349.2/354.3] Radial velocity (VR.A.)
97- 100 F4.1 km/s e_Vra [0.2/53] Vra uncertainty
102- 107 F6.1 km/s Vdec [-357/315] Radial velocity (VDecl)
109- 112 F4.1 km/s e_Vdec [0.2/37] Vdec uncertainty
114- 119 F6.1 km/s Vz [-499/536] Radial velocity (Vz)
121- 125 F5.1 km/s e_Vz [0/154] Vz uncertainty
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Note (1): Source as follows:
t.w. = Radial velocities determined in this work
Tri. = Trippe+ 2008A&A...492..419T 2008A&A...492..419T
Pau. = Paumard+ 2006, J/ApJ/643/1011
Gil. = Gillessen+ 2017, J/ApJ/837/30
Yel. = Yelda+ 2014, J/ApJ/783/131
I. = IRS stars
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 14-Mar-2025