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Young Massive Clusters Near the Galactic Center: Initial Mass Function and Stellar Evolution.

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Item Summary Hosek, Matthew W., Jr 2019-05-28T19:31:41Z 2019-05-28T19:31:41Z 2018-08
dc.title Young Massive Clusters Near the Galactic Center: Initial Mass Function and Stellar Evolution.
dc.type Thesis
dc.contributor.department Astronomy
dcterms.abstract With projected distances of just ~30 pc from Sgr A*, the Arches and Quintuplet clusters are valuable probes of star formation in the extreme Galactic Center (GC) environment. Of particular interest is the Initial Mass Function (IMF), which yields critical insight into the physics driving star formation and is a vital ingredient in many areas of astronomy. We use multi-epoch Hubble Space Telescope (HST) observations to obtain high-precision proper motions of stars beyond the central 25” of these clusters for the first time, calculating cluster membership probabilities down to ~2 M. We achieve significantly cleaner cluster samples than is possible through photometric methods due to severe differential extinction in the field. For the Arches cluster, we 1) measure the stellar radial density profile out to 3 pc for the first time, finding no evidence of a tidal radius and demonstrating that the cluster is much larger than predicted; 2) combine this sample with HST observations of Westerlund 1 to measure the extinction law of highly reddened stars in the Galactic plane between 0.8 μm – 2.2 μm, revealing it to be inconsistent with a single power-law (contrary to long-held assumptions) and significantly steeper than commonly-used extinction laws; and 3) use these observations with K-band spectroscopy to make the first proper motion-based IMF measurement of the cluster, finding significant deviations from the local IMF and suggesting that the IMF of the GC is non-standard. In addition, we show current progress on the analysis of the Quintuplet cluster along with a science case for future studies of both clusters with the James Webb Space Telescope.
dcterms.description Ph.D. Thesis. University of Hawaiʻi at Mānoa 2018.
dcterms.language eng
dcterms.publisher University of Hawaiʻi at Mānoa
dcterms.rights All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
dcterms.type Text
Appears in Collections: Ph.D. - Astronomy

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