Swift and supergiant fast X-ray transients

A novel monitoring approach

P. Romano, L. Sidoli, V. Mangano, Jamie A. Kennea, G. Cusumano, S. Vercellone, H. A. Krimm, David Nelson Burrows, N. Gehrels

Research output: Contribution to journalConference article

Abstract

We describe our monitoring strategy which best exploits the sensitivity and flexibility of Swift to study the long-term behaviour of Supergiant Fast X-ray Transients (SFXTs). We present observations of the recent outbursts from two objects of this class. IGR J16479-4514, underwent an outburst on 2008 March 19, reaching a peak luminosity of about 6×1037 erg s-1 (0.5-100 keV; at a distance of 4.9 kpc). We obtained a simultaneous broad-band spectrum (0.3-100 keV), the first for the SFXT class, which is fit with a heavily absorbed (column density 5×1022 cm-2) hard power-law with a high energy cut-off at about 7 keV. This spectrum shows properties similar to the ones of accreting pulsars, although no X-ray pulsations were found. IGR J11215-5952, one of the only two periodic SFXT known to date, was observed with Swift several times, first with an intense 23-day long monitoring campaign around the 2007 February 9 outburst; then with a 26-day long monitoring around the unexpected July 24 outburst; finally with a deep exposure during the 2008 June 16 outburst. We present the whole dataset, which also includes observations which allowed us to firmly establish the outburst period at P ∼ 165 days. Thanks to our combined observations common characteristics to this class of objects are emerging, i.e., outburst lengths well in excess of hours, often with a multiple peaked structure, dynamic range ∼ 3 orders of magnitude, and periodicities are starting to be found.

Original languageEnglish (US)
JournalProceedings of Science
StatePublished - Dec 1 2008
Event7th INTEGRAL Workshop - An INTEGRAL View of Compact Objects, INTEGRAL 2008 - Copenhagen, Denmark
Duration: Sep 8 2008Sep 11 2008

Fingerprint

x rays
pulsars
dynamic range
periodic variations
emerging
flexibility
cut-off
luminosity
broadband
sensitivity
energy

All Science Journal Classification (ASJC) codes

  • General

Cite this

Romano, P., Sidoli, L., Mangano, V., Kennea, J. A., Cusumano, G., Vercellone, S., ... Gehrels, N. (2008). Swift and supergiant fast X-ray transients: A novel monitoring approach. Proceedings of Science.
Romano, P. ; Sidoli, L. ; Mangano, V. ; Kennea, Jamie A. ; Cusumano, G. ; Vercellone, S. ; Krimm, H. A. ; Burrows, David Nelson ; Gehrels, N. / Swift and supergiant fast X-ray transients : A novel monitoring approach. In: Proceedings of Science. 2008.
@article{e03ddda7a9884a8fb33dad6ef727ffc3,
title = "Swift and supergiant fast X-ray transients: A novel monitoring approach",
abstract = "We describe our monitoring strategy which best exploits the sensitivity and flexibility of Swift to study the long-term behaviour of Supergiant Fast X-ray Transients (SFXTs). We present observations of the recent outbursts from two objects of this class. IGR J16479-4514, underwent an outburst on 2008 March 19, reaching a peak luminosity of about 6×1037 erg s-1 (0.5-100 keV; at a distance of 4.9 kpc). We obtained a simultaneous broad-band spectrum (0.3-100 keV), the first for the SFXT class, which is fit with a heavily absorbed (column density 5×1022 cm-2) hard power-law with a high energy cut-off at about 7 keV. This spectrum shows properties similar to the ones of accreting pulsars, although no X-ray pulsations were found. IGR J11215-5952, one of the only two periodic SFXT known to date, was observed with Swift several times, first with an intense 23-day long monitoring campaign around the 2007 February 9 outburst; then with a 26-day long monitoring around the unexpected July 24 outburst; finally with a deep exposure during the 2008 June 16 outburst. We present the whole dataset, which also includes observations which allowed us to firmly establish the outburst period at P ∼ 165 days. Thanks to our combined observations common characteristics to this class of objects are emerging, i.e., outburst lengths well in excess of hours, often with a multiple peaked structure, dynamic range ∼ 3 orders of magnitude, and periodicities are starting to be found.",
author = "P. Romano and L. Sidoli and V. Mangano and Kennea, {Jamie A.} and G. Cusumano and S. Vercellone and Krimm, {H. A.} and Burrows, {David Nelson} and N. Gehrels",
year = "2008",
month = "12",
day = "1",
language = "English (US)",
journal = "Proceedings of Science",
issn = "1824-8039",
publisher = "Sissa Medialab Srl",

}

Romano, P, Sidoli, L, Mangano, V, Kennea, JA, Cusumano, G, Vercellone, S, Krimm, HA, Burrows, DN & Gehrels, N 2008, 'Swift and supergiant fast X-ray transients: A novel monitoring approach', Proceedings of Science.

Swift and supergiant fast X-ray transients : A novel monitoring approach. / Romano, P.; Sidoli, L.; Mangano, V.; Kennea, Jamie A.; Cusumano, G.; Vercellone, S.; Krimm, H. A.; Burrows, David Nelson; Gehrels, N.

In: Proceedings of Science, 01.12.2008.

Research output: Contribution to journalConference article

TY - JOUR

T1 - Swift and supergiant fast X-ray transients

T2 - A novel monitoring approach

AU - Romano, P.

AU - Sidoli, L.

AU - Mangano, V.

AU - Kennea, Jamie A.

AU - Cusumano, G.

AU - Vercellone, S.

AU - Krimm, H. A.

AU - Burrows, David Nelson

AU - Gehrels, N.

PY - 2008/12/1

Y1 - 2008/12/1

N2 - We describe our monitoring strategy which best exploits the sensitivity and flexibility of Swift to study the long-term behaviour of Supergiant Fast X-ray Transients (SFXTs). We present observations of the recent outbursts from two objects of this class. IGR J16479-4514, underwent an outburst on 2008 March 19, reaching a peak luminosity of about 6×1037 erg s-1 (0.5-100 keV; at a distance of 4.9 kpc). We obtained a simultaneous broad-band spectrum (0.3-100 keV), the first for the SFXT class, which is fit with a heavily absorbed (column density 5×1022 cm-2) hard power-law with a high energy cut-off at about 7 keV. This spectrum shows properties similar to the ones of accreting pulsars, although no X-ray pulsations were found. IGR J11215-5952, one of the only two periodic SFXT known to date, was observed with Swift several times, first with an intense 23-day long monitoring campaign around the 2007 February 9 outburst; then with a 26-day long monitoring around the unexpected July 24 outburst; finally with a deep exposure during the 2008 June 16 outburst. We present the whole dataset, which also includes observations which allowed us to firmly establish the outburst period at P ∼ 165 days. Thanks to our combined observations common characteristics to this class of objects are emerging, i.e., outburst lengths well in excess of hours, often with a multiple peaked structure, dynamic range ∼ 3 orders of magnitude, and periodicities are starting to be found.

AB - We describe our monitoring strategy which best exploits the sensitivity and flexibility of Swift to study the long-term behaviour of Supergiant Fast X-ray Transients (SFXTs). We present observations of the recent outbursts from two objects of this class. IGR J16479-4514, underwent an outburst on 2008 March 19, reaching a peak luminosity of about 6×1037 erg s-1 (0.5-100 keV; at a distance of 4.9 kpc). We obtained a simultaneous broad-band spectrum (0.3-100 keV), the first for the SFXT class, which is fit with a heavily absorbed (column density 5×1022 cm-2) hard power-law with a high energy cut-off at about 7 keV. This spectrum shows properties similar to the ones of accreting pulsars, although no X-ray pulsations were found. IGR J11215-5952, one of the only two periodic SFXT known to date, was observed with Swift several times, first with an intense 23-day long monitoring campaign around the 2007 February 9 outburst; then with a 26-day long monitoring around the unexpected July 24 outburst; finally with a deep exposure during the 2008 June 16 outburst. We present the whole dataset, which also includes observations which allowed us to firmly establish the outburst period at P ∼ 165 days. Thanks to our combined observations common characteristics to this class of objects are emerging, i.e., outburst lengths well in excess of hours, often with a multiple peaked structure, dynamic range ∼ 3 orders of magnitude, and periodicities are starting to be found.

UR - http://www.scopus.com/inward/record.url?scp=84883652264&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84883652264&partnerID=8YFLogxK

M3 - Conference article

JO - Proceedings of Science

JF - Proceedings of Science

SN - 1824-8039

ER -

Romano P, Sidoli L, Mangano V, Kennea JA, Cusumano G, Vercellone S et al. Swift and supergiant fast X-ray transients: A novel monitoring approach. Proceedings of Science. 2008 Dec 1.