The tidal stream generated by the globular cluster NGC 3201. (arXiv:2010.14381v2 [astro-ph.GA] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Palau_C/0/1/0/all/0/1">C. G. Palau</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Miralda_Escude_J/0/1/0/all/0/1">J. Miralda-Escudé</a>
We detect a tidal stream generated by the globular cluster NGC 3201 extending
over ~140 degrees on the sky, using the Gaia DR2 data, with the maximum
likelihood method we presented previously to study the M68 tidal stream. Most
of the detected stream is the trailing one, which stretches in the southern
Galactic hemisphere and passes within a close distance of 3.2 kpc from the Sun,
therefore making the stream highly favorable for discovering relatively bright
member stars, while the leading arm is further from us and behind a disk
foreground that is harder to separate from. The cluster has just crossed the
Galactic disk and is now in the northern Galactic hemisphere, moderately
obscured by dust, and the part of the trailing tail closest to the cluster is
highly obscured behind the plane. We obtain a best-fit model of the stream
which is consistent with the measured proper motion, radial velocity and
distance to NGC 3201, and show it to be the same as the previously detected
Gj”oll stream by Ibata et al. We identify ~200 stars with the highest
likelihood of being stream members using only their Gaia kinematic data. Most
of these stars (170) are photometrically consistent with being members of NGC
3201 when they are compared to the cluster H-R diagram, only once a correction
for dust absorption and reddening by the Galaxy is applied. The remaining stars
are consistent with being random foreground objects according to simulated data
sets. We list these 170 highly likely stream member stars, which will be of
strong interest to model the gravitational potential of the Milky Way and to be
followed up spectroscopically for accurate radial velocities.
We detect a tidal stream generated by the globular cluster NGC 3201 extending
over ~140 degrees on the sky, using the Gaia DR2 data, with the maximum
likelihood method we presented previously to study the M68 tidal stream. Most
of the detected stream is the trailing one, which stretches in the southern
Galactic hemisphere and passes within a close distance of 3.2 kpc from the Sun,
therefore making the stream highly favorable for discovering relatively bright
member stars, while the leading arm is further from us and behind a disk
foreground that is harder to separate from. The cluster has just crossed the
Galactic disk and is now in the northern Galactic hemisphere, moderately
obscured by dust, and the part of the trailing tail closest to the cluster is
highly obscured behind the plane. We obtain a best-fit model of the stream
which is consistent with the measured proper motion, radial velocity and
distance to NGC 3201, and show it to be the same as the previously detected
Gj”oll stream by Ibata et al. We identify ~200 stars with the highest
likelihood of being stream members using only their Gaia kinematic data. Most
of these stars (170) are photometrically consistent with being members of NGC
3201 when they are compared to the cluster H-R diagram, only once a correction
for dust absorption and reddening by the Galaxy is applied. The remaining stars
are consistent with being random foreground objects according to simulated data
sets. We list these 170 highly likely stream member stars, which will be of
strong interest to model the gravitational potential of the Milky Way and to be
followed up spectroscopically for accurate radial velocities.
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