The new Swift SGR J1622.3-1606 ////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12159 SUBJECT: Swift J1822.3-1606: A Probable New SGR in Ground Analysis of BAT Data DATE: 11/07/15 17:35:23 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift Swift J1822.3-1606: A Probable New SGR in Ground Analysis of BAT Data J. R. Cummings (GSFC/UMBC), D. Burrows (PSU), S. Campana (INAF-OAB), J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA), D. M. Palmer (LANL), T. Sakamoto (NASA/UMBC), S. Zane (MSSL-UCL) on behalf of the Swift Team At 2011-07-14 at 12:47:47.1 UTC, Swift-BAT triggered (#457261) on a previously unknown source, Swift J1822.3-1606. This was at the same time as Fermi-GBM trigger #332340476. Only a subthreshold source was detected onboard. There were two subsequent rate increases of similar size, probably from the same source at about T+26 sec and T+308 sec, the latter also causing a rate trigger with no significant source found onboard (#457263). There were also 2 other rate triggers within the same pointing period (about 1650 seconds long), but no significant flux was observed from the source at these times. Each pulse was about 0.005 +- 0.001 sec long. All the emission was < 100 keV. Because of the repeated soft and short rate increases, and the location of the source near the Galactic plane, we tentatively classify this object as a new Soft Gamma-ray Repeater. Combining BAT pulse-height events from the two rate triggers yields a highly significant source detection at RA, Dec 275.595, -16.100, which is: RA (J2000) 18h 22m 22.8s Dec (J2000) -16d 05' 59" with an estimated error of 2.3 arcmin (estimated radius, 90% containment). There was also a rate trigger (#457253) on a longer (~0.1 sec), larger, and harder event that was out of the BAT field of view at T-10754 sec. SWIFT J1822.3-1606 was above the horizon and out of the BAT FOV, and we cannot determine if the event was associated with the source or not. The Swift/BAT hard X-ray transient archive was examined to search for previous emission from SWIFT J1822.3-1606 in daily averages. No significant excess was found back to 2011 June 15 with an average 1-sigma error in the 15-50 keV band of 0.0016 ct/s/cm2 (~7 mCrab). The history of Swift/BAT on-board source detections was examined and we found no previous rate-triggered or image- triggered detections of the source. We have detailed data for two rate increases. A powerlaw fit to the combined spectrum has a photon index of 3.7 +- 0.5. A blackbody fit to the combined spectrum has a marginally better chisquared with a temperature of 4.9 +- 0.5 keV. The combined fluence of the two rate increases for which we have data, using the blackbody model, was (2.0 +- 0.4) x 10^-7 ergs/cm^2 A Swift TOO has been approved, but the source is Moon constrained until at least 17:34 UT on July 15. An observation is planned soon after the source comes out of constraint. This circular has also been posted as ATel #3488: http://www.astronomerstelegram.org/?read=3488 ////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12163 SUBJECT: Swift J1822.3-1606: Swift-XRT detection of the X-ray counterpart DATE: 11/07/16 00:33:30 GMT FROM: Claudio Pagani at U of Leicester C. Pagani, A. P. Beardmore (U. Leicester), J. A. Kennea (PSU) and J. R. Cummings (GSFC/UMBC) report on behalf of the Swift-XRT team. We have analysed 584 s of Photon Counting (PC) XRT data for Swift J1822.3-1606 (Cummings et al. GCN Circ. 12159),  a probable SGR.  The XRT observations started 1.2 days after the  BAT trigger. A bright, uncatalogued X-ray source is detected inside the BAT error circle at RA, Dec 275.5763, -16.0742 which is equivalent to:   RA(J2000)  = 18h 22m 18.32s   Dec(J2000) = -16d 04' 27.2" with an uncertainty of 3.6 arcseconds (radius, 90% containment). This location is 113 arcseconds from the BAT position. ////////////////////////////////////////////////////////////////// ATEL #3488 ATEL #3488 Title: Swift J1822.3-1606: A Probable New SGR in Ground Analysis of BAT Data Author: J. R. Cummings (GSFC/UMBC), D. Burrows (PSU), S. Campana (INAF-OAB), J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA), D. M. Palmer (LANL), T. Sakamoto (NASA/UMBC), S. Zane (MSSL-UCL) on behalf of the Swift Team Queries: jay.cummings@nasa.gov Posted: 15 Jul 2011; 17:36 UT Subjects:X-ray, Gamma Ray, Soft Gamma-ray Repeater At 2011-07-14 at 12:47:47.1 UTC, Swift-BAT triggered (#457261) on a previously unknown source, Swift J1822.3-1606. This was at the same time as Fermi-GBM trigger #332340476. Only a subthreshold source was detected onboard. There were two subsequent rate increases of similar size, probably from the same source at about T+26 sec and T+308 sec, the latter also causing a rate trigger with no significant source found onboard (#457263). There were also 2 other rate triggers within the same pointing period (about 1650 seconds long), but no significant flux was observed from the source at these times. Each pulse was about 0.005 +- 0.001 sec long. All the emission was < 100 keV. Because of the repeated soft and short rate increases, and the location of the source near the Galactic plane, we tentatively classify this object as a new Soft Gamma-ray Repeater. Combining BAT pulse-height events from the two rate triggers yields a highly significant source detection at RA, Dec 275.595, -16.100, which is: RA (J2000) 18h 22m 22.8s Dec (J2000) -16d 05' 59" with an estimated error of 2.3 arcmin (estimated radius, 90% containment). There was also a rate trigger (#457253) on a longer (~0.1 sec), larger, and harder event that was out of the BAT field of view at T-10754 sec. SWIFT J1822.3-1606 was above the horizon and out of the BAT FOV, and we cannot determine if the event was associated with the source or not. The Swift/BAT hard X-ray transient archive was examined to search for previous emission from SWIFT J1822.3-1606 in daily averages. No significant excess was found back to 2011 June 15 with an average 1-sigma error in the 15-50 keV band of 0.0016 ct/s/cm2 (~7 mCrab). The history of Swift/BAT on-board source detections was examined and we found no previous rate-triggered or image- triggered detections of the source. We have detailed data for two rate increases. A powerlaw fit to the combined spectrum has a photon index of 3.7 +- 0.5. A blackbody fit to the combined spectrum has a marginally better chisquared with a temperature of 4.9 +- 0.5 keV. The combined fluence of the two rate increases for which we have data, using the blackbody model, was (2.0 +- 0.4) x 10^-7 ergs/cm^2 A Swift TOO has been approved, but the source is Moon constrained until at least 17:34 UT on July 15. An observation is planned soon after the source comes out of constraint. ////////////////////////////////////////////////////////////////// ATEL #3490 ATEL #3490 Title: SGR 1822-1606 (Swift J1822.3-1606): X-ray spectrum and refined spin period from Swift XRT analysis Author: P. Esposito (INAF-OAC), N. Rea (CSIC-IEEC), G. L. Israel (INAF-OAR) report on behalf of a larger collaboration Queries: gianluca@oa-roma.inaf.it Posted: 16 Jul 2011; 14:49 UT Subjects:X-ray, Neutron Star, Soft Gamma-ray Repeater, Transient, Pulsar We have analysed 1.6 ks s of Photon Counting (PC) XRT data of the new SGR/magnetar candidate Swift J1822.3-1606 (Cummings et al. GCN #12159), including the first 0.6 ks on which Pagani et al. reported in GCN #12163. We found that the source spectrum is well described by a power-law plus blackbody model, modified for the interstellar absorption (reduced chi-squared = 1.04 for 97 degrees of freedom). The best fitting parameters are: nH = 3e+21 cm^-2, photon index Gamma = 0.6, and blackbody temperature equivalent to 0.7 keV. The 0.5-10 kev observed (not corrected for the absorption) flux is approximately 2e-10 ergs/cm^2/s. With a standard folding analysis of the solar system barycentered light curves, we measured a period of 8.434(5) s (1-sigma uncertainty), consistent with the early value by Pagani et al. (GCN 12163). The pulsed fraction defined as (Fmax - Fmin)/(Fmax + Fmin), where Fmax and Fmin are the observed background-subtracted count rates at the peak and at the minimum, is (31 +/- 5)% in the 0.2-10 keV band. Finally we note that Chandra observed the field of Swift J1822.3-1606 three times, on 2006-08-21, 2006-08-27, and 2010-05-27. No source was detected at the XRT position of the SGR (Pagani et al. GCN #12163) in any observation, with 3-sigma upper limits on the 0.5-10 keV X-ray flux below 1e-14 ergs/cm^2/s (assuming nH = 3e+21 cm^-2 and a blackbody with kT = 0.5 keV as the quiescent spectrum).