scholarly journals Really Cool Stars and the Star Formation History at the Galactic Center

2003 ◽  
Vol 597 (1) ◽  
pp. 323-346 ◽  
Author(s):  
R. D. Blum ◽  
Solange V. Ramirez ◽  
K. Sellgren ◽  
K. Olsen
Keyword(s):  
Star Formation ◽  
Galactic Center ◽  
Star Formation History ◽  
Formation History ◽  
Cool Stars

Really Cool Stars and the Star Formation History at the Galactic Center

2003 ◽  
Vol 324 (S1) ◽  
pp. 247-253
Author(s):  
Robert D. Blum ◽  
Solange V. Ram�rez ◽  
Kristen Sellgren ◽  
Knut Olsen
Keyword(s):  
Star Formation ◽  
Galactic Center ◽  
Star Formation History ◽  
Formation History ◽  
Cool Stars

scholarly journals IRAS Observations of the Galactic Center

1989 ◽  
Vol 136 ◽  
pp. 121-128 ◽  
Author(s):  
P. Cox ◽  
R. Laureijs
Keyword(s):  
Near Infrared ◽  
Galactic Center ◽  
Galactic Disk ◽  
Radio Continuum ◽  
Star Formation History ◽  
Zodiacal Light ◽  
Heating Source ◽  
Formation History ◽  
Cool Stars ◽  
Center Area

IRAS observations of the Galactic Center are presented. The maps at 12, 25, 60 and 100 μm have a typical resolution of a few arcmin and cover an area 6×2 deg2 centered on SgrA. All data have been corrected for the zodiacal light contamination and for the diffuse emission associated with the galactic disk. The infrared radiation originating in the Galactic Center arises from well-defined sources which can be identified with known radio sources and from an extended emission which accounts for most of the infrared luminosity. The total infrared luminosity associated with the Galactic Center (area 3°×2°) amounts to 109L⊙. The sources contribute 10% to this luminosity. A comparison with surveys in the radio continuum and in the near infrared is presented. Results are analyzed in terms of star formation history. In particular, it is suggested that the dominant heating source for the dust is the population of cool stars - K and M giants - comprising the galactic nucleus.

scholarly journals High-speed stars: Galactic hitchhikers

2020 ◽  
Vol 638 ◽  
pp. A122 ◽  
Author(s):  
E. Caffau ◽  
L. Monaco ◽  
P. Bonifacio ◽  
L. Sbordone ◽  
M. Haywood ◽  
...  
Keyword(s):  
Star Formation ◽  
High Speed ◽  
Milky Way ◽  
Star Formation History ◽  
Proper Motions ◽  
Orbital Parameters ◽  
Blue Stragglers ◽  
Formation History ◽  
Cool Stars ◽  
Age Estimates

Context. The search for stars born in the very early stages of the Milky Way star formation history is of paramount importance in the study of the early Universe since their chemistry carries irreplaceable information on the conditions in which early star formation and galaxy buildup took place. The search for these objects has generally taken the form of expensive surveys for faint extremely metal-poor stars, the most obvious but not the only candidates to a very early formation. Aims. Thanks to Gaia DR2 radial velocities and proper motions, we identified 72 bright cool stars displaying heliocentric transverse velocities in excess of 500 km s−1. These objects are most likely members of extreme outer-halo populations, either formed in the early Milky Way build-up or accreted from since-destroyed self-gravitating stellar systems. Methods. We analysed low-resolution FORS spectra of the 72 stars in the sample and derived the abundances of a few elements. Despite the large uncertainties on the radial velocity determination, we derived reliable orbital parameters for these objects. Results. The stars analysed are mainly slightly metal poor, with a few very metal-poor stars. Their chemical composition is much more homogeneous than expected. All the stars have very eccentric halo orbits, some extending well beyond the expected dimension of the Milky Way. Conclusions. These stars can be the result of a disrupted small galaxy or they could have been globular cluster members. Age estimates suggest that some of them are evolved blue stragglers, now on the subgiant or asymptotic giant branches.

scholarly journals Metallicity studies of the Galactic center: evidence for a top-heavy star formation history?

2013 ◽  
Vol 9 (S303) ◽  
pp. 252-253
Author(s):  
Francisco Najarro ◽  
Diego de la Fuente ◽  
Tom R. Geballe ◽  
Don F. Figer
Keyword(s):  
Star Formation ◽  
Massive Star ◽  
Local Group ◽  
Galactic Center ◽  
Massive Stars ◽  
Star Formation History ◽  
Test Bed ◽  
Formation History ◽  
History Of ◽  
Stellar Properties

AbstractThe Galactic center (GC) region hosts three of the most massive resolved young clusters in the Local Group and constitutes a test bed for studying the star formation history of the region and inferring the possibility of a top-heavy scenario. Further, recent detection of a large number of apparently isolated massive stars within the inner 80 pc of the Galactic center has raised fundamental questions regarding massive star formation in a such a dense and harsh environment. Noting that most of the isolated massive stars have spectral analogs in the Quintuplet cluster, we have undertaken a combined analysis of the infrared spectra of both selected Quintuplet stars and the isolated objects using Gemini spectroscopy. We present preliminary results, aiming at α-elements versus iron abundances, stellar properties, ages and radial velocities which will differentiate the top-heavy and star-formation scenarios.

scholarly journals The Massive stellar Population at the Galactic Center

2016 ◽  
Vol 12 (S329) ◽  
pp. 287-291
Author(s):  
Francisco Najarro ◽  
Diego de la Fuente ◽  
Tom R. Geballe ◽  
Don F. Figer ◽  
D. John Hillier
Keyword(s):  
Star Formation ◽  
Massive Star ◽  
Stellar Population ◽  
Milky Way ◽  
Local Group ◽  
Galactic Center ◽  
Spectroscopic Studies ◽  
Star Formation History ◽  
Stellar Content ◽  
Formation History

AbstractWe present results from our ongoing infrared spectroscopic studies of the massive stellar content at the Center of the Milky Way. This region hosts a large number of apparently isolated massive stars as well as three of the most massive resolved young clusters in the Local Group. Our survey seeks to infer the presence of a possible top-heavy recent star formation history and to test massive star formation channels: clusters vs isolation.

An Extended Star Formation History for the Galactic Center fromHubble Space TelescopeNICMOS Observations

2004 ◽  
Vol 601 (1) ◽  
pp. 319-339 ◽  
Author(s):  
Donald F. Figer ◽  
R. Michael Rich ◽  
Sungsoo S. Kim ◽  
Mark Morris ◽  
Eugene Serabyn
Keyword(s):  
Star Formation ◽  
Galactic Center ◽  
Star Formation History ◽  
Formation History

scholarly journals 1.3. First stellar iron abundance measurements in the Galactic center

1998 ◽  
Vol 184 ◽  
pp. 21-22 ◽  
Author(s):  
K. Sellgren ◽  
J. S. Carr ◽  
S. C. Balachandran
Keyword(s):  
Star Formation ◽  
Gas Phase ◽  
Chemical Evolution ◽  
Milky Way ◽  
Galactic Center ◽  
Star Formation History ◽  
Stellar Abundances ◽  
Milky Way Galaxy ◽  
Formation History ◽  
Iron Abundance

The disk of the Milky Way galaxy shows evidence for gas-phase abundances which increase with decreasing radius (Simpson et al. 1995; Afflerbach et al. 1997). Sustained star formation in the center of the Milky Way Galaxy may be fueled by inflow of inner disk gas (Serabyn & Morris 1996), suggesting that Galactic Center (GC) stars may be metal-rich. Measurements of stellar abundances in the GC allow us to explore the chemical evolution of our Galaxy's nucleus and to infer its star formation history.

scholarly journals 1.1. The Galactic bulge

1998 ◽  
Vol 184 ◽  
pp. 11-18
Author(s):  
R. Michael Rich
Keyword(s):  
Star Formation ◽  
Globular Clusters ◽  
Galactic Center ◽  
Star Formation History ◽  
Galactic Bulge ◽  
Rich Cluster ◽  
Cluster Systems ◽  
Formation History ◽  
Metallicity Distribution ◽  
Review Current

I review current work on the Galactic bulge, with emphasis on issues that may connect to the environment of the Galactic Center. There is growing evidence that the field population of the bulge at RGC > 500pc is as old as the metal rich Galactic center globular clusters, and that field and clusters have the same spatial and metallicity distribution. We suggest that by analogy, extragalactic metal rich cluster systems, which also tend to follow the spheroid light, are old. On the other hand, there has been long standing evidence for an age gradient toward the Galactic center, and recent observations confirm without doubt that there is active star formation there. If a long-lived bar has been funneling gas (and inducing star formtion) in the central 100 pc, the star formation history there will be complicated and interesting.

scholarly journals 4.3. A large-scale CO imaging of the Galactic center by the Nobeyama 45-m telescope: shell statistics and star formation history

1998 ◽  
Vol 184 ◽  
pp. 171-172
Author(s):  
Tetsuo Hasegawa ◽  
Tomoharu Oka ◽  
Fumio Sato ◽  
Masato Tsuboi ◽  
Atsushi Yamazaki
Keyword(s):  
Star Formation ◽  
High Resolution ◽  
Focal Plane ◽  
Large Scale ◽  
Galactic Center ◽  
Focal Plane Array ◽  
Star Formation History ◽  
Radio Observatory ◽  
Formation History ◽  
Array Receiver

As a key program of the 45-m telescope at Nobeyama Radio Observatory, we have made high-resolution CO images of the Galactic center region with the 2×2 focal plane array receiver. The data consist of 44,000 12CO and 13,000 13CO spectra taken with 16″ beams spaced by 34″. The 12CO image covers roughly −1.5° ≤ l ≤ +3.4° and −0.6° ≤ b ≤ +0.6° (Oka et al. 1997b)

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