The true nature of Terzan 5: the most efficient ``furnace'' of MSPs in the Galaxy
Abstract
Terzan 5 is the globular cluster (GC)-like stellar system harboring the largest known population of MSPs. Using the Multi-Conjugate Adaptive Optics Demonstrator MAD at the ESO-VLT, we recently obtained a superb (K, J-K) color-magnitude diagram, which has revealed the existence of two horizontal branches (HBs) well separated in magnitude and colour (Ferraro et al. 2009, Nature, 462, 483). A prompt spectroscopic follow-up with NIRSPECatKeck has shown that the two populations have (1) significantly different iron content ([Fe/H] = -0.2 and +0.3 for the faint and the bright HB, respectively), (2) distinct [α/Fe] abundance patterns and (3) no evidence of the Al-O anti-correlation commonly observed in GCs. All these properties suggest that Ter 5 is far from being a genuine globular. Instead it has experienced the explosion of a huge number of supernovae (SNe), thus accounting for its high metal content and it should have been much more massive in the past than today, thus to retain the SN ejecta within its potential well. The many type II SNe should have also produced a large number of neutron stars (NSs), which could finally explain its exceptionally large population of MSPs.
- Publication:
-
Radio Pulsars: An Astrophysical Key to Unlock the Secrets of the Universe
- Pub Date:
- August 2011
- DOI:
- 10.1063/1.3615102
- arXiv:
- arXiv:1012.3616
- Bibcode:
- 2011AIPC.1357..147F
- Keywords:
-
- adaptive optics;
- supernovae;
- neutron stars;
- collision processes;
- 95.75.Qr;
- 97.60.Bw;
- 97.60.Jd;
- 98.65.Fz;
- Adaptive and segmented optics;
- Supernovae;
- Neutron stars;
- Galaxy mergers collisions and tidal interactions;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- Contributed Talk at the conference "Radio Pulsars: a key to unlock the secrets of the Universe", Baia Chia, Sardinia, Italy, 11-15 Oct. 2010, 4 pages, 2 figures