An extraordinary cluster of massive young stars in the Milky Way's nucleus

E. Serabyn(1), D. Shupe(2), D. F. Figer(3)


(1) California Institute of Technology, MS 320-47, Pasadena, CA 91125
(2) Jet Propulsion Laboratory, California Institute of Technology, MS 171-113, 4800 Oak Grove Drive, Pasadena, CA 91109
(3) Dept. of Physics and Astronomy, UCLA, Los Angeles, CA 90095

Paper: to appear in Nature

Weblink: http://www.astro.ucla.edu/~figer/papers.html


Abstract:

The mass distribution of newborn stars (the stellar initial mass function, or IMF) is key to the evolution of galaxies, as it determines whether a galaxy's interstellar medium is funneled predominantly into dim, long-lived, low-mass stars, as is the case in normal galactic disks, or into bright, short-lived, massive stars, as is perhaps the case in ``starburst'' nuclei. Our own Galactic nucleus is not a full-fledged starburst, but its star-formation rate per volume is nevertheless well above that of the Galactic disk (by a factor of ~ 103). Even so, the Milky Way's nuclear IMF remains uncertain, because high obscuration and the large background population of bright, elderly giant stars have impeded the detection of normal hydrogen-burning (or ``main-sequence'') stars. Our high-resolution infrared observations of a compact stellar cluster in the nucleus now reveal the presence of numerous young, massive main sequence stars, several of which may number among the Galaxy's most massive. Dwarfing all other known young Galactic clusters, the ``Arches'' cluster may in fact be a weaker analog of the ``super star-clusters'' found in starburst nuclei.


Preprints available from the authors at figer@gc.astro.ucla.edu , or the raw TeX (no figures) if you click here.

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