A proper motion catalogue for the Milky Way's nuclear stellar disc

Shahzamanian, B.; Schoedel, R.; Nogueras-Lara, F.; Martinez-Arranz, A.; Sormani, M. C.; Gallego-Calvente, A. T.; Gallego-Cano, E.; Alburai, A.

doi:10.48550/arxiv.2108.11847

Cited by 2 publications

(10 citation statements)

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“…We tried doing this with one, two, and three-Gaussians models. To estimate the goodness of each fit, we used the logarithm of posterior probability, log Z (see Shahzamanian et al 2021). We found that the best fit is achieved with two Gaussians.…”

Section: Resultsmentioning

confidence: 99%

“…In the Galactic center, at a distance of ∼ 8 kpc (McNamara et al 2000;Ghez et al 2008;Genzel et al 2010), we can find the central molecular zone (CMZ), a flattened structure of gas and dust within a radius of ∼200 pc (Kruijssen et al 2014;Tress et al 2020). Occupying a similar space as the CMZ, there is the socalled nuclear stellar disk (NSD), a rotating structure (Schönrich et al 2015;Shahzamanian et al 2021), with a radius of ∼ 150 pc and a scale height of ∼ 45 pc (Launhardt et al 2002;Gallego-Cano et al 2020;Sormani et al 2020).…”

Section: Introductionmentioning

confidence: 99%

“…In this Letter we cross-check the work of Nogueras-Lara et al (2021a) with kinematic data, considering one of these two possibilities based on the assumption that the Brick is mostly opaque to near-infrared light (Longmore et al 2012) and, therefore, we can only detect stars in front of the cloud. The first option being that the Brick is outside of the NSD and inside the Bulge, in which case we would expect to find only stars with typical Bulge proper motions, in other words zero mean proper motion and isotropic velocity dispersion (Kunder et al 2012;Shahzamanian et al 2021). Alternatively, the second option being that the Brick is inside the NSD, in which case we would expect to find two different kinematic groups: one Article number, page 1 of 5 arXiv:2204.02109v1 [astro-ph.GA] 5 Apr 2022…”

Section: Introductionmentioning

confidence: 99%

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Distance to the Brick cloud using stellar kinematics

Martínez-Arranz

Schödel

Nogueras-Lara

et al. 2022

A&A

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Context. The central molecular zone at the Galactic center is currently being studied intensively to understand how star formation proceeds under the extreme conditions of a galactic nucleus. Knowing the position of molecular clouds along the line of sight toward the Galactic center has had important implications in our understanding of the physics of the gas and star formation in the central molecular zone. It was recently claimed that the dense molecular cloud G0.253 + 0.016 (the Brick) has a distance of ∼7.20 kpc from the Sun. That would place it outside of the central molecular zone, and therefore of the nuclear stellar disk, but still inside the Bulge. Aims. Theoretical considerations as well as observational studies show that stars that belong to the nuclear stellar disk have different kinematics from those that belong to the inner Bulge. Therefore, we aim to constrain the distance to the Brick by studying the proper motions of the stars in the area. Methods. We used ESO HAWK-I/VLT imaging data from epochs 2015 and 2019 to compute proper motions on the Brick and in a nearby comparison field free of dark clouds. Results. The stellar population seen toward the nuclear stellar disk shows the following three kinematic components: (1) Bulge stars with an isotropic velocity dispersion of ∼3.5 micro-arc second per year; (2) eastward moving stars on the near side of the nuclear stellar disk; and (3) westward moving stars on the far side of the nuclear stellar disk. We clearly see all three components toward the comparison field. However, toward the Brick, which blocks the light from stars behind it, we can only see kinematic components (1) and (2). Conclusions. While the Brick blocks the light from stars on the far side of the nuclear stellar disk, the detection of a significant component of eastward streaming stars implies that the Brick must be located inside the nuclear stellar disk and, therefore, that it forms part of the central molecular zone.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Distance to the Brick cloud using stellar kinematics

Martínez-Arranz

Schödel

Nogueras-Lara

et al. 2022

A&A

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“…The NSD is rotating. The rotation of the NSD has been detected in APOGEE spectroscopic data by Schönrich et al (2015), in OH/IR and SiO maser stars by Lindqvist et al (1992) and Habing et al (2006), in ISAAC (VLT) near-infrared integral-field spectroscopy by Feldmeier et al (2014), in classical cepheids by Matsunaga et al (2015), in the KMOS spectroscopic survey by Fritz et al (2021), and in proper motions parallel to the Galactic plane by Shahzamanian et al (2021).…”

Section: Structure Of the Nsdmentioning

confidence: 90%

“…The 𝜇 𝑙 distributions of the NSD in the central fields show a characteristic double-peaked shape (Trippe et al 2008;Schödel et al 2009;Chatzopoulos et al 2015a;Shahzamanian et al 2021). This is due to rotation and can be understood by considering the limiting case of a cold disc of stars in purely circular motion: at 𝑙 = 0 stars move perpendicularly to the line-of-sight, and stars rotating in one sense (and placed in the front side of the NSD) will give rise to one peak, and stars rotating in the opposite sense (and placed on the back side of the NSD) to the other peak.…”

Section: Fiducial Modelmentioning

confidence: 99%

Jeans modelling of the Milky Way’s nuclear stellar disc

Sormani

Magorrian²,

Nogueras-Lara

et al. 2020

Monthly Notices of the Royal Astronomical Society

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The nuclear stellar disc (NSD) is a flattened stellar structure that dominates the gravitational potential of the Milky Way at Galactocentric radii 30 ≲ R ≲ 300 pc. In this paper, we construct axisymmetric Jeans dynamical models of the NSD based on previous photometric studies and we fit them to line-of-sight kinematic data of APOGEE and SiO maser stars. We find that (i) the NSD mass is lower but consistent with the mass independently determined from photometry by Launhardt et al. (2002). Our fiducial model has a mass contained within spherical radius r = 100 pc of $M(r<100\, {\rm pc}) = 3.9 \pm 1 \times 10^8 \, \rm M_\odot$ and a total mass of $M_{\rm NSD} = 6.9 \pm 2 \times 10^8 \, \rm M_\odot$. (ii) The NSD might be the first example of a vertically biased disc, i.e. with ratio between the vertical and radial velocity dispersion σz/σR > 1. Observations and theoretical models of the star-forming molecular gas in the central molecular zone suggest that large vertical oscillations may be already imprinted at stellar birth. However, the finding σz/σR > 1 depends on a drop in the velocity dispersion in the innermost few tens of parsecs, on our assumption that the NSD is axisymmetric, and that the available (extinction corrected) stellar samples broadly trace the underlying light and mass distributions, all of which need to be established by future observations and/or modelling. (iii) We provide the most accurate rotation curve to date for the innermost 500 pc of our Galaxy.

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A proper motion catalogue for the Milky Way's nuclear stellar disc

Cited by 2 publications

References 50 publications

Distance to the Brick cloud using stellar kinematics

Distance to the Brick cloud using stellar kinematics

Jeans modelling of the Milky Way’s nuclear stellar disc

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