Title: A luminous gamma-ray binary in the large magellanic cloud

Abstract

Gamma-ray binaries consist of a neutron star or a black hole interacting with a normal star to produce gamma-ray emission that dominates the radiative output of the system. Previously, only a handful of such systems have been discovered, all within our Galaxy. We report the discovery of a luminous gamma-ray binary in the Large Magellanic Cloud, found with the Fermi Large Area Telescope (LAT), from a search for periodic modulation in all sources in the third Fermi LAT catalog. This is the first such system to be found outside the Milky Way. Furthermore, the system has an orbital period of 10.3 days, and is associated with a massive O5III star located in the supernova remnant DEM L241, previously identified as the candidate high-mass X-ray binary (HMXB) CXOU J053600.0–673507. X-ray and radio emission are also modulated on the 10.3 day period, but are in anti-phase with the gamma-ray modulation. Optical radial velocity measurements suggest that the system contains a neutron star. The source is significantly more luminous than similar sources in the Milky Way, at radio, optical, X-ray, and gamma-ray wavelengths. The detection of this extra-galactic system, but no new Galactic systems, raises the possibility that the predicted number of gamma-raymore » binaries in our Galaxy has been overestimated, and that HMXBs may be born containing relatively slowly rotating neutron stars.« less

Authors:

Corbet, R. H. D. ^[1]; Chomiuk, L.  ^[2];

• Search DOE PAGES for author "Chomiuk, L."
• Search DOE PAGES for ORCID "0000-0002-8400-3705"

Coe, M. J. ^[3]; Coley, J. B.  ^[4];

• Search DOE PAGES for author "Coley, J. B."
• Search DOE PAGES for ORCID "0000-0001-7532-8359"

Dubus, G.  ^[5];

• Search DOE PAGES for author "Dubus, G."
• Search DOE PAGES for ORCID "0000-0002-5130-2514"

Edwards, P. G. ^[6]; Martin, P. ^[7]; McBride, V. A. ^[8]; Stevens, J. ^[6]; Strader, J.  ^[2];

• Search DOE PAGES for author "Strader, J."
• Search DOE PAGES for ORCID "0000-0002-1468-9668"

Townsend, L. J. ^[9]; Udalski, A. ^[10]

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+ Show Author Affiliations

1. Univ. of Maryland Baltimore County (UMBC), Baltimore, MD (United States); NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States); Maryland Inst. College of Art, Baltimore, MD (United States)
2. Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy
3. Univ. of Southampton (United Kingdom). School of Physics and Astronomy
4. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)
5. Univ. of Grenoble (France). Inst. of Planetology nad Astrophysics
6. Commonwealth Scientific and Industrial Research Organization Astronomy and Space Science, New South Wales (Australia)
7. Univ. of Toulouse (France). Inst. of Astrophysical Research and Planetology
8. Univ. of Cape Town (South Africa). Dept. of Astronomy; South African Astronomical Observatory (South Africa)
9. Univ. of Cape Town (South Africa). Dept. of Astronomy
10. Warsaw Univ. Observatory (Poland)

Publication Date:

Tue Sep 27 00:00:00 EDT 2016

Research Org.:

SLAC National Accelerator Lab., Menlo Park, CA (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1355709

Grant/Contract Number:  

AC02-76SF00515

Resource Type:

Accepted Manuscript

Journal Name:

The Astrophysical Journal (Online)

Additional Journal Information:

Journal Name: The Astrophysical Journal (Online); Journal Volume: 829; Journal Issue: 2; Journal ID: ISSN 1538-4357

Publisher:

Institute of Physics (IOP)

Country of Publication:

United States

Language:

English

Subject:

79 ASTRONOMY AND ASTROPHYSICS; gamma rays: stars; stars: individual (CXOU J053600.0-673507); stars: neutron