ATel #11952: IGR J17503-2636: a new X-ray transient discovered by INTEGRAL and confirmed by Swift

J. Chenevez, G. Jaisawal, E. Kuulkers, C. Sanchez-Fernandez, A. Bazzano, A. Paizis, A. Bodaghee, S. Brandt, N. Lund, E. Bozzo, C. Ferrigno

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Referred to by ATel #: 11990, 11992

The X-ray monitor JEM-X on-board the INTEGRAL satellite has discovered a new X-ray transient source during the recent Galactic Bulge observation performed on August 11th (revolution 1986) from UTC 07:44 to 12:30 (ATel #438, Kuulkers et al. 2007, A&A 466, 595, see also:
The source is detected at 7 σ for an effective exposure time of 17.9 ks on the combined JEM-X mosaics from which we obtain the following fluxes:
12 ±2 mCrab (≈2.0×10-10 erg/cm2/s) between 3-10 keV,
17 ±3 mCrab (≈1.9×10-10 erg/cm2/s) between 10-25 keV.
JEM-X sees the source at the following position:
RA = 267.58°, Dec = -26.61° with an uncertainty of 1.5 arcmin
leading to the new source name: IGR J17503-2636.
The source is not detected by IBIS/ISGRI above 20 keV, and we estimate a 3-σ upper limit about 10 mCrab (20-40 keV).
Thanks to a 1-ks exposure with Swift/XRT in PC mode between August 13th 19:41-20:13 (UTC) we can refine the source position at:
RA = 267.57527° = 17h 50m 18.06s
Dec = -26.60458° = -26d 36m 16.5s.
The error radius is 2.2 arcsec (90% confidence) obtained with the enhanced method using Swift/UVOT provided by the on-line Swift/XRT data product tool (Evans et al. 2009, MNRAS 397,
The Swift/XRT 0.3-10 keV count rate was increasing between the two snapshots from 0.3 to 0.5 c/s.
The average spectrum is highly absorbed with a derived absorption column between (6.2-13.7)×1022 cm-2 (for a galactic column density of 1.3×1022 cm-2 in that direction). The
observed 0.3-10 keV flux is estimated between (2.0-8.3)×10-11 erg/cm2/s.
The next INTEGRAL observations of the Galactic Bulge region are currently scheduled on August 17th and will continue at a rough cadence of one-two observations per week until October 20th.
Multi-wavelength follow-up observations are encouraged to unveil the nature of IGR J17503-2636.
We thank the Swift Team for scheduling the ToO observation with short notice.
Original languageEnglish
Publication date2019
Number of pages1
Publication statusPublished - 2019
SeriesThe Astronomer's telegram


  • X-ray
  • Transient

Cite this

Chenevez, J., Jaisawal, G., Kuulkers, E., Sanchez-Fernandez, C., Bazzano, A., Paizis, A., Bodaghee, A., Brandt, S., Lund, N., Bozzo, E., & Ferrigno, C. (2019). ATel #11952: IGR J17503-2636: a new X-ray transient discovered by INTEGRAL and confirmed by Swift. The Astronomer's telegram