scholarly journals Proper motions of thin filaments at the Galactic Center

2006 ◽  
Vol 2 (S238) ◽  
pp. 415-416
Author(s):  
K. Mužić ◽  
A. Eckart ◽  
R. Schödel ◽  
L. Meyer ◽  
A. Zensus
Keyword(s):  
Adaptive Optics ◽  
Milky Way ◽  
Galactic Center ◽  
Proper Motions ◽  
Thin Filaments ◽  
Motion Study ◽  
L Band ◽  
Central Parsec ◽  
Stellar Envelopes ◽  
Shock Fronts

AbstractWe present the proper motion study of the thin filaments observed in L'-band (3.8 μm) adaptive optics images of the central parsec of the Milky Way. Observed filaments are associated with the mini-spiral and, in some cases, with stars. They can be interpreted as shock fronts formed by the interaction of a central wind with the mini-spiral or extended dusty stellar envelopes.

scholarly journals Adaptive optics $\vec{L}$-band observations of the Galactic Center region

2001 ◽  
Vol 376 (1) ◽  
pp. 124-135 ◽  
Author(s):  
Y. Clénet ◽  
D. Rouan ◽  
E. Gendron ◽  
J. Montri ◽  
F. Rigaut ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Galactic Center ◽  
Center Region ◽  
L Band

scholarly journals Infrared Imaging of the Arches Cluster - Adaptive Optics in the Densest Region of the Milky Way

2002 ◽  
Vol 207 ◽  
pp. 132-134
Author(s):  
Andrea Stolte ◽  
Eva K. Grebel ◽  
Wolfgang Brandner ◽  
Donald F. Figer
Keyword(s):  
Adaptive Optics ◽  
Milky Way ◽  
Infrared Imaging ◽  
Galactic Center ◽  
Cluster Formation ◽  
Extreme Environment ◽  
Mass Function ◽  
Cluster Center ◽  
Limiting Factor ◽  
Dense Cluster

The Arches cluster - located only 11′ from the Galactic Center (GC) - is one of the densest and richest young star clusters in the Milky Way. With an age of only about 2 Myr, it is ideally suited to study massive cluster formation in an extreme environment. We find an IMF slope of Γ = −0.77 from 5 to 100 M⊙, in good agreement with the results from HST/NICMOS from Figer et al. (1999). The limiting factor in the dense cluster center is crowding. With the new AO systems, high resolution analysis of the dense cluster region combined with very deep infrared photometry is available. We have analysed deep H and K′ images of the cluster center obtained with the GEMINI/Hokupa'a adaptive optics system. Colour-magnitude diagrams and the IMF are constructed from these data. A comparison with isochrones yields the mass function.

scholarly journals Using ground based data as a precursor for Gaia in getting proper motions of satellites

2017 ◽  
Vol 12 (S330) ◽  
pp. 210-213
Author(s):  
Tobias K. Fritz ◽  
Sean T. Linden ◽  
Paul Zivick ◽  
Nitya Kallivayalil ◽  
Jo Bovy
Keyword(s):  
Adaptive Optics ◽  
Globular Cluster ◽  
Proper Motion ◽  
Milky Way ◽  
Dwarf Galaxy ◽  
Optical Data ◽  
Line Of Sight ◽  
Wide Field ◽  
Proper Motions ◽  
Tidal Stream

AbstractWe present our effort to measure the proper motions of satellites in the halo of the Milky Way with mainly ground based telescopes as a precursor on what is possible with Gaia. For our first study, we used wide field optical data from the LBT combined with a first epoch of SDSS observations, on the globular cluster Palomar 5 (Pal 5). Since Pal 5 is associated with a tidal stream it is very useful to constrain the shape of the potential of the Milky Way. The motion and other properties of the Pal 5 system constrain the inner halo of the Milky Way to be rather spherical. Further, we combined adaptive optics and HST to get an absolute proper motion of the globular cluster Pyxis. Using the proper motion and the line-of-sight velocity we find that the orbit of Pyxis is rather eccentric with its apocenter at more than 100 kpc and its pericenter at about 30 kpc. The dynamics excludes an association with the ATLAS stream, the Magellanic clouds, and all satellites of the Milky Way at least down to the mass of Leo II. However, the properties of Pyxis, like metallicity and age, point to an origin from a dwarf of at least the mass of Leo II. We therefore propose that Pyxis originated from an unknown relatively massive dwarf galaxy, which is likely today fully disrupted. Assuming that Pyxis is bound to the Milky Way we derive a 68% lower limit on the mass of the Milky Way of 9.5 × 1011 M⊙.

scholarly journals 10.2. High proper motions in the vicinity of Sgr A∗: unambiguous evidence for a massive central black hole

1998 ◽  
Vol 184 ◽  
pp. 433-434
Author(s):  
A. M. Ghez ◽  
B. L. Klein ◽  
C. McCabe ◽  
M. Morris ◽  
E. E. Becklin
Keyword(s):  
Black Hole ◽  
Milky Way ◽  
Galactic Center ◽  
Robust Method ◽  
Proper Motions ◽  
Central Black Hole ◽  
Milky Way Galaxy ◽  
The Galaxy ◽  
Sgr A

Although the notion that the Milky Way galaxy contains a supermassive central black hole has been around for more than two decades, it has been difficult to prove that one exists. The challenge is to assess the distribution of matter in the few central parsecs of the Galaxy. Assuming that gravity is the dominant force, the motion of the stars and gas in the vicinity of the putative black hole offers a robust method for accomplishing this task, by revealing the mass interior to the radius of the objects studied. Thus objects located closest to the Galactic Center provide the strongest constraints on the black hole hypothesis.

scholarly journals Thin filaments at the Galactic Center: identification and proper motions

2006 ◽  
Vol 54 ◽  
pp. 311-315
Author(s):  
K Muzić ◽  
A Eckart ◽  
R Schödel ◽  
L Meyer ◽  
A Zensus
Keyword(s):  
Galactic Center ◽  
Proper Motions ◽  
Thin Filaments

scholarly journals SiO and H2O Masers in the Central Parsec of the Galaxy

1998 ◽  
Vol 164 ◽  
pp. 229-230 ◽  
Author(s):  
Karl M. Menten ◽  
Mark J. Reid
Keyword(s):  
Galactic Center ◽  
Radio Continuum ◽  
Continuum Emission ◽  
Proper Motions ◽  
Infrared Images ◽  
Evolved Stars ◽  
The Galaxy ◽  
Sgr A ◽  
Central Parsec ◽  
Infrared Sources

AbstractWe have discovered maser emission from SiO and H2O molecules toward a number of evolved stars within the central parsec of our Galaxy. The maser positions can be registered with milliarcsecond precision relative to the radio continuum emission of the nonthermal Galactic center source Sgr A*. Since the masing stars are prominent infrared sources, our data can be used to locate the position of Sgr A* on infrared images of the Galactic center region. Using VLBA observations it will be possible to measure proper motions of the maser stars, which can be used to put constraints on the mass distribution in the central parsec.

scholarly journals Young stellar disks formed by the collision of a molecular cloud with a circumnuclear disk at the Galactic center

2013 ◽  
Vol 9 (S303) ◽  
pp. 185-187 ◽  
Author(s):  
C. Alig ◽  
M. Schartmann ◽  
A. Burkert ◽  
K. Dolag
Keyword(s):  
Accretion Disks ◽  
Molecular Cloud ◽  
Milky Way ◽  
Galactic Center ◽  
Multiple Streams ◽  
Central Black Hole ◽  
Circumnuclear Disk ◽  
Central Parsec ◽  
Ring Material ◽  
New Formation

AbstractWe suggest a new formation mechanism for the inclined, sub-parsec scale and counterrotating stellar disks observed around the central black hole in the Milky Way Galactic center. The simulation of a single molecular cloud crashing into a circumnuclear ring of gas leads to the inflow of multiple streams of gas towards the central parsec region. The time delayed arrival of those streams forms multiple, sub-parsec scale accretion disks, with angular momentum depending on the ratio of cloud and circumnuclear ring material. These accretion disks could then be the progenitors which fragmented into the observed stellar disks. A similar event might have also led to the creation of the so-called minispiral in the Galactic center.

Structure and Kinematics of the Milky Way

2017 ◽  
Vol 13 (S336) ◽  
pp. 148-153 ◽  
Author(s):  
Mark J. Reid
Keyword(s):  
Rotation Curve ◽  
Milky Way ◽  
Spiral Structure ◽  
Galactic Center ◽  
Rotation Speed ◽  
Information Modeling ◽  
High Mass ◽  
Proper Motions ◽  
Dimensional Phase Space ◽  
The Galaxy

AbstractMaser astrometry is now providing parallaxes with accuracies of ±10 micro-arcseconds, which corresponds to 10% accuracy at a distance of 10 kpc! The VLBA BeSSeL Survey and the Japanese VERA project have measured ≈200 parallaxes for masers associated with young, high-mass stars. Since these stars are found in spiral arms, we now are directly mapping the spiral structure of the Milky Way. Combining parallaxes, proper motions, and Doppler velocities, we have complete 6-dimensional phase-space information. Modeling these data yields the distance to the Galactic Center, the rotation speed of the Galaxy at the Sun, and the nature of the rotation curve.

scholarly journals New constraints on the structure of the nuclear stellar cluster of the Milky Way from star counts and MIR imaging

2020 ◽  
Vol 634 ◽  
pp. A71 ◽  
Author(s):  
E. Gallego-Cano ◽  
R. Schödel ◽  
F. Nogueras-Lara ◽  
H. Dong ◽  
B. Shahzamanian ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Milky Way ◽  
Galactic Center ◽  
Galactic Plane ◽  
3D Structure ◽  
Major Axis ◽  
Stellar Disk ◽  
Axis Ratio ◽  
Stellar Cluster ◽  
Red Clump

Context. The Milky Way nuclear star cluster (MWNSC) is a crucial laboratory for studying the galactic nuclei of other galaxies, but its properties have not been determined unambiguously until now. Aims. We aim to study the size and spatial structure of the MWNSC. Methods. This study uses data and methods that address potential shortcomings of previous studies on the topic. We use 0.2″ angular resolution Ks data to create a stellar density map in the central 86.4 pc × 21 pc at the Galactic center. We include data from selected adaptive-optics-assisted images obtained for the inner parsecs. In addition, we use Spitzer/IRAC mid-infrared (MIR) images. We model the Galactic bulge and the nuclear stellar disk in order to subtract them from the MWNSC. Finally, we fit a Sérsic model to the MWNSC and investigate its symmetry. Results. Our results are consistent with previous work. The MWNSC is flattened with an axis ratio of q = 0.71 ± 0.10, an effective radius of Re = (5.1 ± 1.0) pc, and a Sérsic index of n = 2.2 ± 0.7. Its major axis may be tilted out of the Galactic plane by up to −10°. The distribution of the giants brighter than the Red Clump (RC) is found to be significantly flatter than the distribution of the faint stars. We investigate the 3D structure of the central stellar cusp using our results on the MWNSC structure on large scales to constrain the deprojection of the measured stellar surface number density, obtaining a value of the 3D inner power law of γ = 1.38 ± 0.06sys ± 0.01stat. Conclusions. The MWNSC shares its main properties with other extragalactic NSCs found in spiral galaxies. The differences in the structure between bright giants and RC stars might be related to the existence of not completely mixed populations of different ages. This may hint at recent growth of the MWNSC through star formation or cluster accretion.

scholarly journals Constraining the Variability and Binary Fraction of Galactic Center Young Stars

2016 ◽  
Vol 11 (S322) ◽  
pp. 237-238
Author(s):  
Abhimat K. Gautam ◽  
Tuan Do ◽  
Andrea M. Ghez ◽  
Jessica R. Lu ◽  
Mark R. Morris ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Adaptive Optics ◽  
Binary Systems ◽  
Main Sequence ◽  
Milky Way ◽  
Galactic Center ◽  
Young Stars ◽  
Early Type ◽  
Eclipsing Binary ◽  
Early Type Stars

AbstractWe present constraints on the variability and binarity of young stars in the central 10 arcseconds (~ 0.4 pc) of the Milky Way Galactic Center (GC) using Keck Adaptive Optics data over a 12 year baseline. Given our experiment’s photometric uncertainties, at least 36% of our sample’s known early-type stars are variable. We identified eclipsing binary systems by searching for periodic variability. In our sample of spectroscopically confirmed and likely early-type stars, we detected the two previously discovered GC eclipsing binary systems. We derived the likely binary fraction of main sequence, early-type stars at the GC via Monte Carlo simulations of eclipsing binary systems, and find that it is at least 32% with 90% confidence.

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