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X-ray, optical, and infrared investigation of the candidate supergiant fast X-ray transient IGR J18462 - 0223

X-ray, optical, and infrared investigation of the candidate supergiant fast X-ray transient IGR J18462 - 0223
X-ray, optical, and infrared investigation of the candidate supergiant fast X-ray transient IGR J18462 - 0223
We report on a broad-band X-ray study (0.5-60 keV) of the poorly known candidate Supergiant Fast X-ray Transient (SFXT) IGR J18462-0223, and on optical and near-infrared (NIR) followup observations of field objects. The out-of-outburst X-ray state has been investigated for the first time with archival INTEGRAL/IBIS, ASCA, Chandra and Swift/XRT observations. This allowed us to place stringent 3 sigma upper limits on the soft (0.5-10 keV) and hard (18-60 keV) X-ray emission of 2.9x10-13 erg cm-2 s-1 and 8x10-12 erg cm-2 s-1, respectively; the source was also detected during an intermediate soft X-ray state with flux equal to 1.6x10-11 erg cm-2 s-1 (0.5-10 keV). In addition, we report on the INTEGRAL/IBIS discovery of three fast hard X-ray flares (18-60 keV) having a duration in the range 1-12 hours: the flaring behavior was also investigated in soft X-rays (3-10 keV) with archival INTEGRAL/JEM-X observations. The duty cycle (1.2%) and the dynamic ranges (> 1,380 and > 190 in the energy bands 0.5-10 keV and 18-60 keV, respectively) were measured for the first time. Archival UKIDSS JHK NIR data, together with our deep R-band imaging of the field, unveiled a single, very red object inside the intersection of the Swift/XRT and XMM-Newton error circles: this source has optical/NIR photometric properties compatible with a very heavily absorbed blue supergiant located at about 11 kpc, thus being a strong candidate counterpart for IGR J18462-0223. NIR spectroscopy is advised to confirm the association. Finally, a hint of a possible orbital period was found at about 2.13 days. If confirmed by further studies, this would make IGR J18462-0223 the SFXT with the shortest orbital period among the currently known systems.
0004-6361
1-9
Sguera, V.
371bb568-7e56-496e-a624-dba6de79d9e1
Drave, S.P.
e34f14fb-0a86-439f-9a64-a69dfc733672
Sidoli, L.
2207422d-1a4d-448c-8c0b-8f0c2bf78a18
Masetti, N.
78166fad-2a82-4de5-9359-25706c0a6e2f
Landi, R.
b8243478-d7a1-4774-8a66-4158a65a33d3
Bird, A.J.
e69d3bd1-3dbd-461b-92dd-1704b5dc1b8b
Bazzano, A.
8eef0c6e-1a5f-4bcd-a034-9a5c3b29104d
Sguera, V.
371bb568-7e56-496e-a624-dba6de79d9e1
Drave, S.P.
e34f14fb-0a86-439f-9a64-a69dfc733672
Sidoli, L.
2207422d-1a4d-448c-8c0b-8f0c2bf78a18
Masetti, N.
78166fad-2a82-4de5-9359-25706c0a6e2f
Landi, R.
b8243478-d7a1-4774-8a66-4158a65a33d3
Bird, A.J.
e69d3bd1-3dbd-461b-92dd-1704b5dc1b8b
Bazzano, A.
8eef0c6e-1a5f-4bcd-a034-9a5c3b29104d

Sguera, V., Drave, S.P., Sidoli, L., Masetti, N., Landi, R., Bird, A.J. and Bazzano, A. (2013) X-ray, optical, and infrared investigation of the candidate supergiant fast X-ray transient IGR J18462 - 0223. Astronomy & Astrophysics, 556, 1-9, [A27]. (doi:10.1051/0004-6361/201220785).

Record type: Article

Abstract

We report on a broad-band X-ray study (0.5-60 keV) of the poorly known candidate Supergiant Fast X-ray Transient (SFXT) IGR J18462-0223, and on optical and near-infrared (NIR) followup observations of field objects. The out-of-outburst X-ray state has been investigated for the first time with archival INTEGRAL/IBIS, ASCA, Chandra and Swift/XRT observations. This allowed us to place stringent 3 sigma upper limits on the soft (0.5-10 keV) and hard (18-60 keV) X-ray emission of 2.9x10-13 erg cm-2 s-1 and 8x10-12 erg cm-2 s-1, respectively; the source was also detected during an intermediate soft X-ray state with flux equal to 1.6x10-11 erg cm-2 s-1 (0.5-10 keV). In addition, we report on the INTEGRAL/IBIS discovery of three fast hard X-ray flares (18-60 keV) having a duration in the range 1-12 hours: the flaring behavior was also investigated in soft X-rays (3-10 keV) with archival INTEGRAL/JEM-X observations. The duty cycle (1.2%) and the dynamic ranges (> 1,380 and > 190 in the energy bands 0.5-10 keV and 18-60 keV, respectively) were measured for the first time. Archival UKIDSS JHK NIR data, together with our deep R-band imaging of the field, unveiled a single, very red object inside the intersection of the Swift/XRT and XMM-Newton error circles: this source has optical/NIR photometric properties compatible with a very heavily absorbed blue supergiant located at about 11 kpc, thus being a strong candidate counterpart for IGR J18462-0223. NIR spectroscopy is advised to confirm the association. Finally, a hint of a possible orbital period was found at about 2.13 days. If confirmed by further studies, this would make IGR J18462-0223 the SFXT with the shortest orbital period among the currently known systems.

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1305.1538 - Author's Original
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Published date: 2013
Organisations: Physics & Astronomy

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Local EPrints ID: 369345
URI: http://eprints.soton.ac.uk/id/eprint/369345
ISSN: 0004-6361
PURE UUID: d075c13d-161d-4e63-821a-d3555bee6c58

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Date deposited: 24 Sep 2014 10:31
Last modified: 14 Mar 2024 18:01

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Contributors

Author: V. Sguera
Author: S.P. Drave
Author: L. Sidoli
Author: N. Masetti
Author: R. Landi
Author: A.J. Bird
Author: A. Bazzano

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