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Detection of VHE gamma-rays from HESS j0632+057 during the 2011 february X-ray outburst with the magic telescopes

By Pedro Antoranz Canales, Juan Abel Barrio Uña, José Luis Contreras González, Mª Victoria Fonseca González, Marcos López Moya, José Miguel Miranda Pantoja, Daniel Nieto, Konstanzja Satalecka and Valeria Scapin

Abstract

The very high energy (VHE) gamma-ray source HESS J0632+057 has recently been confirmed to be a gamma-ray binary. The optical counterpart is the Be star MWC 148, and a compact object of unknown nature orbits it every similar to 321 days with a high eccentricity of similar to 0.8. We monitored HESS J0632+057 with the stereoscopic MAGIC telescopes from 2010 October to 2011 March and detected significant VHE gamma-ray emission during 2011 February, when the system exhibited an X-ray outburst. We find no gamma-ray signal in the other observation periods when the system did not show increased X-ray flux. Thus, HESS J0632+057 exhibits gamma-ray variability on timescales of the order of one to two months possibly linked to the X-ray outburst that takes place about 100 days after the periastron passage. Furthermore, our measurements provide for the first time the gamma-ray spectrum down to about 140 GeV and indicate no turnover of the spectrum at low energies. We compare the properties of HESS J0632+057 with the similar gamma-ray binary LS I +61 degrees 303 and discuss the possible origin of the multi-wavelength emission of the source

Topics: Electricidad, Electrónica, Física nuclear
Publisher: IOP Publishing
Year: 2012
DOI identifier: 10.1088/2041-8205
OAI identifier: oai:www.ucm.es:20733
Provided by: EPrints Complutense

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