New Density Profile and Structural Parameters of the Complex Stellar System Terzan 5
Abstract
Terzan 5 is a globular cluster-like stellar system in the Galactic bulge which has been recently found to harbor two stellar populations with different iron content and probably different ages. This discovery suggests that Terzan 5 may be the relic of a primordial building block that contributed to the formation of the Galactic bulge. Here we present a re-determination of the structural parameters (center of gravity, density and surface brightness profiles, total luminosity, and mass) of Terzan 5, as obtained from the combination of high-resolution (ESO-MAD and Hubble Space Telescope ACS-WFC) and wide-field (ESO-WFI) observations. We find that Terzan 5 is significantly less concentrated and more massive than previously thought. Still it has the largest collision rate of any stellar aggregate in the Galaxy. We discuss the impact of these findings on the exceptional population of millisecond pulsars harbored in this stellar system.
Based on observations collected at the European Southern Observatory, Cerro Paranal (during the Science Demonstration of MAD) and La Silla (under proposal 278.D-5067), Chile. Also based on observations with the NASA/ESA HST, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS5-26555.- Publication:
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The Astrophysical Journal
- Pub Date:
- July 2010
- DOI:
- 10.1088/0004-637X/717/2/653
- arXiv:
- arXiv:1005.2847
- Bibcode:
- 2010ApJ...717..653L
- Keywords:
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- globular clusters: individual: Terzan 5;
- stars: evolution;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 17 pages, 4 figures