Please use this identifier to cite or link to this item:
|Title:||The Gamma-Ray Source AGL J2241+4454 as the Possible Counterpart of MWC 656||Authors:||Munar-Adrover, Pere
Nguyen, L. H.
|Issue Date:||2016||Journal:||THE ASTROPHYSICAL JOURNAL||Number:||829||Issue:||2||Abstract:||AGILE discovered the transient source AGL J2241+4454 in 2010, which triggered the study of the associated field allowing for the discovery of the first Be/black hole binary system: MWC 656. This binary was suggested to be the counterpart of AGL J2241+4454, but this association is still not robust. In this work we explore the archival AGILE and Fermi/Large Area Telescope (LAT) data to find more transient events compatible with AGL J2241+4454 and address the possibility to link them to the accretion/ejection processes of MWC 656. We found a total of nine other transient events with AGILE compatible with the position of AGL J2241+4454, besides the 2010 one. We folded these events with the period of the binary system and we could not associate the gamma-ray activity with any particular orbital phase. By stacking the 10 transient events we obtained a spectrum that extends between 100 MeV and 1 GeV, and we fitted it with a power law with a photon index Γ = 2.3 +/- 0.2. We searched the Fermi/LAT data in order to complement the gamma-ray information provided by AGILE but no significant results arose. To investigate this apparent contradiction between these telescopes, we studied the exposure of the field of AGL J2241+4454 in both instruments, and found significant differences. In particular, AGILE exposed, for a longer time and at a lower off-axis angular distance, the field of AGL J2241+4454. This fact, together with the energy-dependent sensitivity of both instruments, and the soft spectrum found in the stacking analysis, might explain why AGILE observed the transient events not seen by Fermi/LAT.||URI:||http://hdl.handle.net/20.500.12386/29551||URL:||https://iopscience.iop.org/article/10.3847/0004-637X/829/2/101||ISSN:||0004-637X||DOI:||10.3847/0004-637X/829/2/101||Bibcode ADS:||2016ApJ...829..101M||Fulltext:||open|
|Appears in Collections:||1.01 Articoli in rivista|
Show full item record
Files in This Item:
|Munar_2016_ApJ_829_101.pdf||pdf editoriale||900.61 kB||Adobe PDF||View/Open|
checked on Aug 4, 2021
checked on Aug 4, 2021
Items in DSpace are published in Open Access, unless otherwise indicated.