The Orbital Period of the Wolf-Rayet Binary IC 10 X-1: Dynamic Evidence that the Compact Object Is a Black Hole

Abstract

. (2007) 'The orbital period of the Wolf-Rayet binary IC 10 X-1 : dynamic evidence that the compact ob ject is a black hole.', Astrophysical journal letters., 669 (1). L21-L24.Further information on publisher's website: Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ABSTRACT IC 10 X-1 is a bright (L X p 10 38 ergs s Ϫ1 ) variable X-ray source in the Local Group starburst galaxy IC 10. The most plausible optical counterpart is a luminous Wolf-Rayet star, making IC 10 X-1 a rare example of a Wolf-Rayet X-ray binary. In this Letter, we report on the detection of an X-ray orbital period for IC 10 X-1 of 34.4 hr. This result, combined with a reexamination of optical spectra, allows us to determine a mass function for the system of M , and a probable mass for the compact object of 24-33 M , . If this analysis is f (M) p 7.8 correct, the compact object is the most massive stellar-mass black hole known. We further show that the observed period is inconsistent with Roche lobe overflow, suggesting that the binary is detached and that the black hole is accreting the wind of the Wolf-Rayet star. The observed mass-loss rate of [MAC92] 17A is sufficient to power the X-ray luminosity of IC 10 X-1.

(No) dynamical constraints on the mass of the black hole in two ULXs

“…We can take encouragement from the recent reports of mass functions for two extragalactic BHBs, M33 X-8 and IC 10 X-1 (Orosz et al 2007;Prestwich et al 2007;Silverman & Filippenko 2008). However, most ULXs are at least three times more distant than these objects, with m V ∼ 20.5 at best (Motch, these proceedings) and more typically m V > 24 (Roberts, Levan & Goad 2008).…”

Two Eclipsing Ultraluminous X-Ray Sources in M51

“…Its donor star periodically eclipses the thermal bremsstrahlung radiation (L 10 X 36 erg s −1 ) from the base of the jet. The first unambiguous eclipsing behavior in a candidate BH X-ray binary outside the Milky Way was found in IC 10 X-1, located in a Local Group dwarf galaxy, with a Wolf-Rayet donor star, a binary period of 1.45 days, and an X-ray luminosity » L 10 X 38 erg s −1 (Prestwich et al 2007;Laycock et al 2015a;Steiner et al 2016). For IC 10 X-1, it is still disputed whether the accreting compact object is a BH or a neutron star (Laycock et al 2015b).…”

Sources of Gravitational Waves: Theory and Observations

“…The largest confirmed BH mass in the stellar range is ∼ 15 M [332], but there are hints of even heavier BHs of 23-34M [333]. Theoretically, low metallicity massive stars could lead to BHs of 50M or higher [317].…”