J/A+A/684/A214 Photometry and proper motion cat. in NSD region (Zoccali+, 2024)
Observed kinematics of the Milky Way nuclear stellar disk region.
Zoccali M., Rojas-Arriagada A., Valenti E., Contreras Ramos R.,
Valenzuela-Navarro A., Salvo-Guajardo C.
<Astron. Astrophys. 684, A214 (2024)>
=2024A&A...684A.214Z 2024A&A...684A.214Z (SIMBAD/NED BibCode)
ADC_Keywords: Galactic plane ; Milky Way ; Photometry, CCD ; Proper motions
Keywords: Galaxy: kinematics and dynamics - Galaxy: nucleus -
Galaxy: stellar content - Galaxy: structure
Abstract:
The nuclear region of the Milky Way, within approximately -1<l<+1 and
-0.3<b<+0.3 (i.e., |l|<150pc, |b|<45pc) is believed to host a
Nuclear Stellar Disk, co-spatial with the gaseous Central Molecular
Zone. Previous kinematical studies detect faster rotation for the
stars belonging to the Nuclear Stellar Disk, compared to the
surrounding regions. We analyse the rotation velocity of stars at the
Nuclear Stellar Disk, and compare them with its analogue in a few
control fields just outside this region. We limit our analysis to
stars in the Red Clump of the Color Magnitude Diagram, in order to be
able to relate their mean de-reddened luminosity with distance along
the line of sight. We use a Proper Motion catalogue, obtained from
Point Spread Function photometry on VISTA Variables in the Via a
Lactea images, to construct maps of the transverse velocity for these
stars. We complement our analysis with radial velocities from the 17th
data release of the APOGEE survey. We find that the main difference
between the Nuclear Stellar Disk region and its surroundings is that
at the former we see only stars moving eastwards, that we believe are
located in front of the Galactic Center. On the contrary, in every
other direction, we see the brightest Red Clump stars moving
eastwards, and the faintest ones moving westwards, as expected for a
rotating disk. We interpret this observations as produced by the
Central Molecular Zone, hiding stars behind itself. What we observe is
compatible with being produced just by the absence of the component at
the back, without requiring the presence of a cold, fast rotating
disk. This component is also not clearly detected in the newest
release of the APOGEE catalogue. In other words, we find no clear
signature of the Nuclear Stellar Disk as a distinct kinematical
component. This work highlights the need for nearby control fields
when attempting to characterize the properties of the Nuclear Stellar
Disk, as the different systematics affecting this region, compared to
nearby ones, might introduce spurious results. Deep, wide field and
high resolution photometry of the inner 4 degrees of the Milky Way is
needed, in order to understand the structure and kinematics of this
very unique region of our Galaxy.
Description:
VVV photometry and proper motions for a sample of red clump stars in
the nuclear stellar disk region.
The ID of each star contains three bits of information separated by
underscores: the tile name in VVV survey data, the chip/pawprint used
to perform the photometry, and a correlative index produced by DAOphot
while performing the photometry in each chip. Galactic longitude is
folded around the bulge minor axis, i. e. it can take negative values.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 121 6096101 Photometry and proper motion catalogue in the
Nuclear Stellar Disk (NSD) region
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- ID Star ID (bNNNNNNNNNNN)
22- 31 F10.6 deg GLON [-2.5/2.5] Galactic longitude
33- 42 F10.6 deg GLAT [-1.2/1.2] Galactic latitude
44- 50 F7.4 mag Jmag ? J-band magnitude
52- 57 F6.4 mag e_Jmag ? Error of J-band magnitude
59- 65 F7.4 mag Hmag H-band magnitude
67- 72 F6.4 mag e_Hmag Error of H-band magnitude
74- 80 F7.4 mag Kmag K-band magnitude
82- 87 F6.4 mag e_Kmag Error of K-band magnitude
89- 96 F8.3 mas/yr pml ? Proper motion component in the direction
parallel to the Galactic plane (mu_l)
98-104 F7.3 mas/yr e_pml ? Error on pml
106-113 F8.3 mas/yr pmb ? Proper motion component in the direction
perpendicular to the Galactic plane (mu_b)
115-121 F7.3 mas/yr e_pmb ? Error on pmb
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Acknowledgements:
Manuela Zoccali, mzoccali(at)uc.cl
(End) Manuela Zoccali [IA PUC], Patricia Vannier [CDS] 21-Feb-2024