2008ApJ...688.1235M


C.D.S. - SIMBAD4 rel 1.7 - 2020.11.25CET07:53:22

2008ApJ...688.1235M - Astrophys. J., 688, 1235-1249 (2008/December-1)

Models for the observable system parameters of ultraluminous X-ray sources.

MADHUSUDHAN N., RAPPAPORT S., PODSIADLOWSKI P. and NELSON L.

Abstract (from CDS):

We investigate the evolution of model populations of ultraluminous X-ray sources (ULXs), consisting of a black hole accretor in a binary with a donor star. Two of the models we consider invoke stellar-mass (up to ∼25 M) black hole binaries (LMBHs), generated with a binary population synthesis code, while a third model uses intermediate-mass (∼1000 M) black hole accretors (IMBHs). For each model, we computed 30,000 binary evolution sequences. A scheme for calculating the optical flux from ULXs is discussed. We present ``probability images'' for the color-magnitude diagrams (CMDs) and for the orbital period-X-ray luminosity (Porb-Lx) plane. We show how a population of luminous X-ray sources in a cluster of stars evolves with time. The most probable ULX system parameters correspond to high-mass donors (of initial mass ≳25 M) with effective O through late B spectral types, and Porb between 1 and 10 days. Estimates of the numbers of ULXs in a typical galaxy as a function of Lx are also presented. We find that if LMBHs are allowed to have super-Eddington Lx, the binding energy parameter for the stellar envelope of the black hole progenitor must be λ≲0.03 in order not to overproduce ULXs. Comparison of six known ULX counterparts with our model CMDs indicates that the IMBH model somewhat more closely matches the observations. We find that a significant contribution to the optical flux from the IMBH systems comes from intrinsic accretion disk radiation. In effect, IMBH systems, when operating at their maximum luminosities (1041-1042 ergs/s), are milli-AGNs. While models of IMBH systems during the X-ray phase are attractive, their formation mechanism remains uncertain.

Abstract Copyright:

Journal keyword(s): Accretion, Accretion Disks - Stars: Binaries: General - Black Hole Physics - Galaxies: Star Clusters - X-Rays: Binaries

Simbad objects: 11

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Number of rows : 11

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 2E 756 ULX 03 18 22.00 -66 36 04.3   23.5 23.6     O9.5 194 3
2 UGC 4305 IG 08 19 04.9878269182 +70 43 13.025604473 12.06 11.72 11.39 11.11   ~ 700 2
3 [SST2011] J081929.00+704219.3 ULX 08 19 28.99 +70 42 19.4           ~ 158 2
4 [FK2005] 7 SNR 09 55 32.95 +69 00 33.6   23.87 23.89     ~ 80 1
5 M 81 Sy2 09 55 33.17306143 +69 03 55.0609270   7.89 6.94     ~ 4009 5
6 NGC 4559 H2G 12 35 57.6399424116 +27 57 35.859639262   10.46 10.01     ~ 542 1
7 RX J123558+27577 UX? 12 35 58.56 +27 57 41.9           ~ 36 2
8 M 101 GiP 14 03 12.583 +54 20 55.50   8.46 7.86 7.76   ~ 2579 2
9 [FK2005] 25 ULX 14 03 19.63 -41 22 58.7           ~ 198 0
10 NGC 5408 EmG 14 03 20.907 -41 22 39.75   12.59   11.96 12.2 ~ 319 3
11 [JRW2005b] 122 UX? 14 03 32.38 +54 21 03.0   21.13       ~ 99 0

    Equat.    Gal    SGal    Ecl

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2020.11.25-07:53:22

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