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Paper: |
HST Paα Survey of the Galactic Center – Seeking the Missing Young Stellar Populations within the Galactic Center |
Volume: |
439, The Galactic Center: a Window to the Nuclear Environment of Disk Galaxies |
Page: |
104 |
Authors: |
Dong, H.; Wang, Q. D.; Cotera, A.; Stolovy, S.; Morris, M. R.; Mauerhan, J.; Mills, E. A.; Schneider, G.; Lang, C. |
Abstract: |
We present preliminary results of our HST Paα survey of
the Galactic Center (GC), which maps the central
0.65×0.25 degrees around Sgr A*. This survey provides us
with a more complete inventory of massive stars within the GC,
compared to previous observations. We find 152 Paα emitting sources, which are evolved massive
stars. Half of them are located outside of three young massive
star clusters near Sgr A*. The spatial distribution of
these field sources suggests that they are within less massive
star clusters/groups, compared to the three massive ones. Our
Paα mosaic not only resolves previously well-known
large-scale filaments into fine structures, but also reveals many
new extended objects, such as bow shocks and H II regions. In
particular, we find two regions with large-scale Paα
diffuse emission and tens of Paα emitting sources in the
negative Galactic longitude suggesting recent star formation
activities, which were not known previously. Furthermore, in our
survey, we detect ∼0.6 million stars, most of which are red
giants or AGB stars. Comparisons of the magnitude distribution in
1.90 μm and those from the stellar evolutionary tracks with
different star formation histories suggest an episode of star
formation process about 350 Myr ago in the GC. |
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