ATel #7098: INTEGRAL detection of a hard X-ray transient in NGC 6440

E. Kuulkers*, E. Bozzo, A. Bazzano, V. Beckmann, T. Bird, A. Bodaghee, J. Chenevez, M. Del Santo, A. Domingo, P. Jonker, P. Kretschmar, A. Paizis, K. Pottschmidt, C. Markwardt, C. Sanchez-Fernandez, R. Wijnands

*Corresponding author for this work

Research output: Other contributionNet publication - Internet publicationResearch

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Abstract

Referred to by ATel #: 7106, 7136, 7183
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During INTEGRAL Galactic bulge monitoring (e.g., ATel #438) observations performed on UT 2015 February 17 at 12.53-16:45, IBIS/ISGRI detected renewed activity at hard X-rays from a transient within the Globular Cluster NGC 6440. The best determined position is: RA, Dec (J2000) = 267.208, -20.314 degrees, with an error radius of 2.4 arcmin (90% c.l.). Formally, there is no known X-ray source within the error circle, so we label the source as IGR J17488-2018. The hard X-ray transient is detected at a significance of 11 (6.5) sigma on the IBIS/ISGRI mosaic in the 20-40 keV (40-80 keV) energy band. The IBIS/ISGRI spectrum (total exposure time of 12 ks) provides a photon index of 2.4 +/- 0.5 and a 20-100 keV flux of 4.8E-10 ergs/cm^2/s. NGC 6440 was outside the JEM-X field-of-view for the entire observation. The Globular Cluster NGC 6440 is known to host millisecond X-ray pulsars (see, e.g., ATel #2672), so it is possible that INTEGRAL detected an outburst from one of these sources. We can not rule out that one of the known X-ray sources just outside the error circle (such as MXB 1746-20 aka H1745-203) is experiencing an outburst. Note that Swift/BAT also detects enhanced activity from H1745-203 over the last days. Further INTEGRAL observations in the direction of NGC 6440 are planned for the coming weeks. Swift ToO follow-up observations have been requested. Observations at other wavelengths are encouraged.
Original languageEnglish
Publication date2015
VolumeATel #7098
Number of pages1
Publication statusPublished - 2015
SeriesThe Astronomer's telegram

Keywords

  • Binary
  • Globular Cluster
  • Neutron Star
  • Transient
  • Variables
  • Pulsar

Cite this

Kuulkers, E., Bozzo, E., Bazzano, A., Beckmann, V., Bird, T., Bodaghee, A., Chenevez, J., Del Santo, M., Domingo, A., Jonker, P., Kretschmar, P., Paizis, A., Pottschmidt, K., Markwardt, C., Sanchez-Fernandez, C., & Wijnands, R. (2015). ATel #7098: INTEGRAL detection of a hard X-ray transient in NGC 6440. The Astronomer's telegram http://www.astronomerstelegram.org/?read=7098