Query : 2010A&A...523A..33S

2010A&A...523A..33S - Astronomy and Astrophysics, volume 523, A33-33 (2010/11-2)

Probing isolated compact remnants with microlensing.


Abstract (from CDS):

We consider isolated compact remnants (ICoRs), i.e. neutrons stars and black holes that do not reside in binary systems and therefore cannot be detected as X-ray binaries. ICoRs may represent ∼5 percent of the stellar mass budget of the Galaxy, but they are very hard to detect. Here we explore the possibility of using microlensing to identify ICoRs. In a previous paper we described a simulation of neutron star evolution in phase space in the Galaxy, taking into account the distribution of the progenitors and the kick at formation. Here we first reconsider the evolution and distribution of neutron stars and black holes with an added a bulge component. From the new distributions we calculate the microlensing optical depth, event rate and distribution of event time scales, comparing and contrasting the case of ICoRs and ``normal stars''. We find that the contribution of remnants to optical depth is slightly lower than without kinematics, owing to the evaporation from the Galaxy. On the other hand, the relative contribution to the rate of events is a factor ∼5 higher. In all, ∼6-7 percent of the events are likely related to ICoRs. In particular, ∼30-40 percent of the events with duration >100 days are possibly related to black holes. It seems therefore that microlensing observations are a suitable tool to probe the population of Galactic ICoRs.

Abstract Copyright:

Journal keyword(s): stars: kinematics and dynamics - stars: neutron - Galaxy: stellar content

Simbad objects: 5

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Number of rows : 5
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 13679 0
2 NAME Baade Window reg 18 03.5 -30 01           ~ 591 3
3 NAME Galactic Bar reg ~ ~           ~ 1142 0
4 NAME Galactic Bulge reg ~ ~           ~ 4096 0
5 NAME Magnificent Seven ? ~ ~           ~ 69 1

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