On the possible orbital motion of Sgr A* in the smooth potential of the Milky Way. (arXiv:2104.03229v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Nikiforov_I/0/1/0/all/0/1">Igor' I. Nikiforov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Veselova_A/0/1/0/all/0/1">Angelina V. Veselova</a>
The modern accuracy of measurements allows the residual/peculiar
(Galactocentric) velocity of the supermassive black hole (SMBH) in our Galaxy,
Sgr A*, on the order of several kilometers per second. We integrate possible
orbits of the SMBH along with the surrounding nuclear star cluster (NSC) for a
barred model of the Galaxy using modern constraints on the components of the
SMBH Galactocentric velocity. Is is shown that the range of oscillations of the
SMBH + NSC in a regular Galactic field in the plane of the Galaxy allowed by
these constraints strongly depends on the set of central components of the
Galactic potential. If the central components are represented only by a
bulge/bar, for a point estimate of the SMBH Galactocentric velocity, the
oscillation amplitude does not exceed 7 pc in the case that a classical bulge
is present and reaches 25 pc if there is no bulge; with SMBH velocity
components within the $2sigma$ significance level, the amplitude can reach 15
and 50 pc, respectively. However, when taking into account the nuclear stellar
disk (NSD), even in the absence of a bulge, the oscillation amplitude is only 5
pc for the point estimate of the SMBH velocity, and 10 pc for the $2sigma$
significance level. Thus, the possible oscillations of the SMBH + NSC complex
from the confirmed components of the Galaxy’s potential are mostly limited by
the NSD, and even taking into account the uncertainty of the mass of the
latter, the oscillation amplitude can hardly exceed $13,text{pc}=6’$.
The modern accuracy of measurements allows the residual/peculiar
(Galactocentric) velocity of the supermassive black hole (SMBH) in our Galaxy,
Sgr A*, on the order of several kilometers per second. We integrate possible
orbits of the SMBH along with the surrounding nuclear star cluster (NSC) for a
barred model of the Galaxy using modern constraints on the components of the
SMBH Galactocentric velocity. Is is shown that the range of oscillations of the
SMBH + NSC in a regular Galactic field in the plane of the Galaxy allowed by
these constraints strongly depends on the set of central components of the
Galactic potential. If the central components are represented only by a
bulge/bar, for a point estimate of the SMBH Galactocentric velocity, the
oscillation amplitude does not exceed 7 pc in the case that a classical bulge
is present and reaches 25 pc if there is no bulge; with SMBH velocity
components within the $2sigma$ significance level, the amplitude can reach 15
and 50 pc, respectively. However, when taking into account the nuclear stellar
disk (NSD), even in the absence of a bulge, the oscillation amplitude is only 5
pc for the point estimate of the SMBH velocity, and 10 pc for the $2sigma$
significance level. Thus, the possible oscillations of the SMBH + NSC complex
from the confirmed components of the Galaxy’s potential are mostly limited by
the NSD, and even taking into account the uncertainty of the mass of the
latter, the oscillation amplitude can hardly exceed $13,text{pc}=6’$.
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