NOAO >   Observing Info >   Approved Programs >   2017B-0057

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Program Information for 2017B-0057


PI: Sebastian Gomez, Harvard U., sgomez@cfa.harvard.edu
Address: Astronomy Department, 60 Garden Street, Cambridge, Massachusetts 02138 United States

CoI: Jonathan Grindlay, Harvard U.

Title: Spectroscopy of a likely new black hole X-ray binary and Cygnus X-1 progenitor

Abstract: HD96670 is a single-line spectroscopic binary made up of an O8.5V primary with variable HeII emission, and an unseen secondary (Sota, et al. 2014). We observed the source and determined a mass function of $f(M) = 0.1161 pm 0.0046$ M_Sun. For an O8.5 primary, this implies a minimum secondary mass of $M_2 > 3.5 pm 0.5 M_Sun$, ruling out a neutron star or white dwarf secondary. We don’t see any spectral signatures that can be associated with a main sequence companion $> 3.5$M_Sun. The source also shows X-ray emission above 10keV with a photon index $sim 2.5$ (Grindlay, et al. in prep). These arguments favor a black hole secondary, if confirmed this would be the third to fifth dynamically confirmed black hole high mass X-ray binary known in the galaxy (Besides Cyg X-1 and MWC 656).

Program Type: Standard/LCO

Scheduled Nights:
Run 1 (2017B):  LCO-1m/NRES -- 10hrs


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NOAO >   Observing Info >   Approved Programs >   2017B-0057

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