SGR 1627-41 This contains GCN Circulars and IAU Circulars about this source since 1998. Items are listed in chronological order. ///////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 107 SUBJECT: Discovery of a new SGR source, SGR1627-41 DATE: 98/06/18 03:36:20 GMT FROM: Chryssa Kouveliotou at MSFC C. Kouveliotou, Universities Space Research Association, M. Kippen, P. Woods, G. Richardson, University of Alabama in Huntsville, V. Connaughton, National Research Council, report on behalf of the BATSE team at NASA/Marshall Space Flight Center: BATSE has detected repeated soft gamma-ray bursts consistent with the same (previously unknown) location. We recorded three bursts on June 15.109, 15.296, 15.411 UT (BATSE triggers 6825, 6826, 6827, respectively) with an average duration of ~ 200 milliseconds. Preliminary spectral analysis of the data indicates that the events are very soft, with power law spectral indices varying between -3.0 and -7.0. BATSE triggered 5 more times, on June 17.873, 17.901, 18.004, 18.035, and 18.071 UT (BATSE trigger numbers 6833, 6834, 6835, 6836 and 6837, respectively). The last trigger had a peak count rate of over 300000 counts/sec above background (integrated over 4 detectors between 20-1000 keV, in 1 second interval) and a duration of ~ 3 seconds. Due to its very high peak intensity, deadtime effects prevent us from using it for localization, until we receive more data types. The weighted location of the 7 remaining triggers is centered on R.A. = 16h27m12.0s and dec = -41d06.0' with an error radius of about 2 degrees. This location does not correspond to any previously known SGR source; we conclude that we have discovered a new source, SGR1627-41. We have initiated an RXTE ToO and we strongly encourage wide field observations at other wavelengths. ///////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 110 SUBJECT: SGR 1627-41 DATE: 98/06/18 18:49:41 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley, Space Sciences Laboratory, on behalf of the Ulysses Gamma-Ray Burst Team and C. Kouveliotou, Universities Space Research Association, on behalf of the Gamma-Ray Observatory BATSE team, report: "This soft gamma repeater (IAUC 6944) has been observed by Ulysses. Triangulation gives a preliminary annulus whose center is at (equinox 2000.0) R.A. = 22h01m40s, Decl. = -10o09'.8, and whose radius is 76.771 +/- 0.05 deg. This annulus intersects the BATSE error circle and forms an error box with an area of approximately 1700 sq. arcmin. Further refinement of this position is possible. An image may be found at http://ssl.berkeley.edu/ipn3/sgr1627-41/" This message may be cited. ///////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 111 SUBJECT: SGR1627-41, BeppoSAX-GRBM detections DATE: 98/06/18 22:31:25 GMT FROM: Marco Feroci at IAS/CNR Frascati M. Feroci, E. Costa, L. Amati, L. Piro and B. Martino, Istituto di Astrofisica Spaziale (CNR, Rome), L. Di Ciolo and A. Coletta, BeppoSAX Science Operation Center (Rome), F. Frontera, Istituto Tecnologie e Studio Radiazioni Extraterrestri (CNR, Bologna), report: "The Gamma Ray Burst Monitor (GRBM) onboard BeppoSAX has detected bursts from a direction consistent with the new Soft Gamma-ray Repeater SGR1627-41 (Kouveliotou et al., GCN #107 and IAUC 6944). Two events were triggered on June 17.90091 (consistent with BATSE trigger n. 6834) and 18.15556. The duration of the events is about 90 and 40 milliseconds respectively. The spectral index, assuming a power law function, is (3.0+/-0.3) and (2.5+/-0.3) respectively in the 40-700 keV energy band. These detections are in agreement with those reported by BATSE and with the harder energy range of the GRBM. Data analysis is in progress to find out other bursts from the same source." This message may be cited. ///////////////////////////////////////////////////////////////////// Circular No. 6945 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science) URL http://cfa-www.harvard.edu/iau/cbat.html Phone 617-495-7244/7440/7444 (for emergency use only) SGR 1627-41 M. Feroci, E. Costa, L. Amati, L. Piro, and B. Martino, Istituto di Astrofisica Spaziale, CNR, Rome; L. Di Ciolo and A. Coletta, BeppoSAX Science Operation Center, Rome; and F. Frontera, Istituto Tecnologie e Studio Radiazioni Extraterrestri, CNR, Bologna, report: "The Gamma Ray Burst Monitor (GRBM) onboard BeppoSAX has detected bursts from a direction consistent with the new soft gamma-ray repeater SGR 1627-41 (IAUC 6944). Two events were triggered on June 17.90091 (consistent with BATSE trigger 6834) and 18.15556 UT. The durations of the events are about 90 and 40 ms, respectively. The spectral indices, assuming a power- law function, are 3.0 +/- 0.3 and 2.5 +/- 0.3, respectively, in the energy band 40-700 keV. These detections are in agreement with those reported by BATSE and with the harder-energy range of the GRBM. Data analysis is in progress to identify other bursts from the same source." (C) Copyright 1998 CBAT 1998 June 18 (6945) Daniel W. E. Green ///////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 113 SUBJECT: Reduced error box of SGR 1627-41 DATE: 98/06/19 03:40:23 GMT FROM: Chryssa Kouveliotou at MSFC SGR 1627-41 P. Woods, M. Kippen, Jan van Paradijs, University of Alabama in Huntsvile, C. Kouveliotou, M. McCollough, Universities Space Research Association, K. Hurley, Space Sciences Laboratory, report: " BATSE Earth limb considerations limit the possible position of this SGR to declinations along the IPN annulus reported in GCN # 110, which are between -43 and -49 degrees. This is slightly outside the BATSE 1 sigma error circle reported in GCN # 107. However, due to the soft spectrum of the source systematic errors were larger than usual. A preliminary search through the MOST SNR catalog (Whiteoak and Green, A&A Suppl. Ser. 118, 329, 1996) reveals only one candidate within the error box reported here, G337.0-0.1. The peculiar nothermal structure core reported for G337.0-0.1 is entirely within the IPN annulus width. We strongly encourage follow-up observations of the SNR source. ///////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 115 SUBJECT: SGR1627-41, Refined IPN annulus location DATE: 98/06/19 13:55:01 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley, Space Sciences Laboratory, on behalf of the Ulysses Gamma-Ray Burst Team and C. Kouveliotou, USRA, M. Kippen, P. Woods, UAH, on behalf of the Gamma-Ray Observatory BATSE team, report: "We have obtained a refined IPN annulus for this soft gamma repeater (IAUC 6944 and GCN 110). Its center is at (equinox 2000.0) R.A. = 22h01m40s, Decl. = -10o09'.8, and its radius is 76.769 +/- 0.028 deg. This annulus is contained within the previous one. Considerable further refinement of this position is possible. An image may be found at http://ssl.berkeley.edu/ipn3/sgr1627-41/" ///////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 116 SUBJECT: SGR1627-41, RXTE/ASM observations DATE: 98/06/19 17:20:20 GMT FROM: Don Smith at MIT D. A. Smith and A. M. Levine, on behalf of the RXTE/ASM teams at MIT and NASA/GSFC, report: "Although the ASM did not observe any of the BATSE-detected events from SGR 1627-41, during the interval from Jun 15 to Jun 19, three short (<~1 s) burst events were detected in SSC 3 at May 17.943917, 17.954243, and 18.010803 (UTC). During the first event, the original BATSE location (GCN 107) was outside the FOV of the ASM. The full width of the FOV of SSC 3 during the first event restricts the range of declination values along the IPN annulus (GCN 115) between -44.4 and -56.4 degrees. This is fully consistent with the revised BATSE position reported in GCN 113. Due to low signal-to-noise, our standard cross-correlation technique was unable to isolate these events in our position data, but given the IPN annulus, we were able to search along it for a best-fit location. We find a minimum reduced chi-squared at R.A. = 16h35m50s, Decl.= -47o32' for event 1 and R.A. = 16h35m50s, Decl.= -47o39' for event 2 (1-sigma error of 4' in Decl. in both cases). Both positions are consistent with the location of the SNR (g337.0-0.1) mentioned in GCN 113. If we assume these bursts are coming from SNR G337.0-0.1, we can use its location to measure the burst fluxes: Event Fluence Peak Flux (2-12 keV) (10^{-7} erg/cm^2) (10^{-7} erg/cm^2/s) 1.5-3 3-5 5-12 kev (1-s averages) 1 <0.6 <0.4 2.1 (+- 0.3) 1.1 2 <0.8 <0.4 2.9 (+- 0.5) 2.8 Upper limits are 2-sigma. We do not yet have pointing information for the observation of the third burst." ///////////////////////////////////////////////////////////////////// Circular No. 6948 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science) URL http://cfa-www.harvard.edu/iau/cbat.html Phone 617-495-7244/7440/7444 (for emergency use only) SGR 1627-41 P. Woods, M. Kippen, and Jan van Paradijs, University of Alabama in Huntsville; C. Kouveliotou and M. McCollough, Universities Space Research Association; and K. Hurley, Space Sciences Laboratory, communicate: "BATSE Earth-limb considerations limit the possible position of this object to declinations along the IPN annulus reported by Hurley et al. (below), which are between -43 deg and -49 deg. This is slightly outside the BATSE 1-sigma error circle reported on IAUC 6944. However, due to the soft spectrum of the source, systematic errors were larger than usual. A preliminary search through the MOST supernova remnant (SNR) catalogue (Whiteoak and Green 1996, A.Ap. Suppl. 118, 329) reveals only one candidate within the error box reported here, G337.0-0.1. The peculiar nonthermal-structure core reported for G337.0-0.1 is entirely within the IPN annulus width. We strongly encourage follow-up observations of the SNR source." Hurley, on behalf of the Ulysses Gamma-Ray Burst Team; and Kouveliotou, Kippen, and Woods, on behalf of the Gamma-Ray Observatory BATSE team, report: "We have obtained an IPN annulus for this soft gamma-ray repeater (IAUC 6944). Its center is at R.A. = 22h01m40s, Decl. = -10o09'.8 (equinox 2000.0), and its radius is 76.769 +/- 0.028 deg. Considerable further refinement of this position is possible. An image may be found at http://ssl.berkeley.edu/ipn3/sgr1627-41/." (C) Copyright 1998 CBAT 1998 June 19 (6948) Daniel W. E. Green ///////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 121 SUBJECT: Radio observations of SGRs DATE: 98/07/01 17:10:46 GMT FROM: Dale A Frail at NRAO D. A. Frail, National Radio Astronomy Observatory and S. R. Kulkarni, California Institute of Technology report: The recent renewed activity from SGR1900+14 (GCN #94) and the newly-discovered SGR1627-41 (GCN #107) prompted VLA radio observations at 8.46 GHz on 1998 June 25. For SGR1900+14 we observed a field centered on the proposed X-ray/infrared counterpart (Hurley et al. ApJ, 463, L13, 1996, Vrba et al. ApJ, 468, 225, 1996). For SGR1627-41 we observed the 95 arcsec diameter supernova remnant CTB33 (IAU Circ. 6948), most recently studied by Sarma, Goss, Green & Frail (ApJ, 483, 335, 1997). The synthesized beam was approximately 1 arcsec. The interferometer is insensitive to extended structure on angular scales larger than 20 arcsec. No point sources were visible above 200 microJy and 345 microJy (4-sigma) for the SGR1900+14 and SGR1627-41, respectively. This report can be cited. ///////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 122 SUBJECT: SGR1627-41 DATE: 98/07/03 23:44:44 GMT FROM: Kevin Hurley at UCBerkeley/SSL SGR 1627-41 K. Hurley, Space Sciences Laboratory, T. Cline, P. Butterworth, NASA GSFC, E. Mazets and S. Golenetskii, Ioffe Institute, on behalf of the Ulysses and Konus-Wind teams, report: "We have triangulated the position of this soft gamma repeater using 7 Konus-Ulysses events between 17 and 22 June. A typical annulus has a center at (equinox 2000.0) R.A.=22h03m04s, Decl.=-9o49'.8, and a radius 77.247 +/- 0.013 degrees. Around the position of the supernova remnant G337.0-0.1, this annulus nests within the one reported previously (IAUC 6948), but is considerably narrower. Around this position, the 7 annuli give results which are mutually consistent to better than 10 arcseconds. The positions of the annuli suggest that if the source of the bursts is indeed within the SNR, it lies between the two radio lobes. An image may be found at http://ssl.berkeley.edu/ipn3/sgr1627-41/. These preliminary annuli can be refined further." This message may be cited. ///////////////////////////////////////////////////////////////////// Circular No. 6966 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science) URL http://cfa-www.harvard.edu/iau/cbat.html Phone 617-495-7244/7440/7444 (for emergency use only) SGR 1627-41 K. Hurley, Space Sciences Laboratory; T. Cline and P. Butterworth, Goddard Space Flight Center, NASA; and E. Mazets and S. Golenetskii, Ioffe Institute, on behalf of the Ulysses and Konus-Wind teams, report: "We have triangulated the position of this soft gamma-ray repeater using seven Konus-Ulysses events between June 17 and 22. A typical annulus has a center at R.A. = 22h03m04s, Decl. = -9o49'.8 (equinox 2000.0), and a radius of 77.247 +/- 0.013 deg. Around the position of the supernova remnant (SNR) G337.0-0.1, this annulus nests within the one reported previously (IAUC 6948), but is considerably narrower. Around this position, the seven annuli give results that are mutually consistent to better than 10". The positions of the annuli suggest that, if the source of the bursts is indeed within the SNR, it lies between the two radio lobes. An image may be found at http://ssl.berkeley.edu/ipn3/sgr1627-41/." (C) Copyright 1998 CBAT 1998 July 4 (6966) Daniel W. E. Green ///////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7777 SUBJECT: Reactivation of SGR 1627-41 DATE: 08/05/29 00:34:50 GMT FROM: David Palmer at LANL D. Palmer (LANL), P. Esposito (INAF-IASF Milano), S. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), G. L. Israel (INAF-OA Roma), H. Krimm (GSFC/USRA), T. Sakamoto (GSFC/ORAU), R. Starling (U. of Leicester) Swift has detected the resumption of activity of Soft Gamma Repeater SGR 1627-41 after a 9.8-year long quiescent period. BAT detected the initial burst on 2008-05-28 at 08:21:43 UT, and a larger burst at 09:53:00. This was followed by a 'forest' of dozens of bursts extending at least to 10:25:54. The brightest burst seen thus far has a 15-50 keV flux of 550 times the Crab, averaged over a 0.128 second time interval. Following the BAT detection, Swift observed the source with XRT on 2008 May 28th, starting from 12:58:14 UT. This SGR was discovered in 1998 June when it emitted over 100 bursts clustered within 6 weeks (Kouveliotou et al. 1998, IAU Circ. 6944, 2; Woods et al. 1999, ApJ 519, L139); no further burst emission has been reported to date. Preliminary results, based on the first 2 ks XRT observation, found a persistent and relatively constant X-ray source with a count rate of 0.06 +/- 0.01 cts/s at a position RA, Dec = 16 35 51.9, -47 35 23.0 (J2000) with an uncertainty of 4.1 arcsec (radius, 90% confidence level). This position is consistent with the Chandra coordinates of the SGR (Wachter et al. 2004, ApJ 615, 887). The paucity of detected photons did not allow us to carry out a sensitive search for coherent pulsations (upper limits > 100% pulsed fraction at 3 sigma c.l.). A single absorbed black body model fits well the spectrum with nH=6.8x10^22 cm^-2 and kT=0.8 keV (Mereghetti et al. 2006, A&A 450, 759). The observed flux is 6.5x10^-12 erg/cm2/s (unabsorbed: 7.3x10^-11). This persistent luminosity is the highest ever recorded from this source (and a factor ~50 higher than the September 2004 XMM-Newton values; Mereghetti et al. 2006). Analysis of data from this burst is continuing, and will be reported in later circulars. A plot of the BAT light curve for the forest can be seen at . The timeline of the previous outbursts can be seen at . We thank the Swift Operations Duty Scientist and Flight Operations Team for performing a rapid ToO. This GCN is also being submitted as an ATEL. ///////////////////////////////////////////////////////////////////// ATEL #1548 ATEL #1548 Title: Reactivation of Soft Gamma Repeater 1627-41 Author: D. Palmer (LANL), P. Esposito (INAF-IASF Milano), S. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), G. L. Israel (INAF-OA Roma), H. Krimm (GSFC/USRA), T. Sakamoto (GSFC/ORAU), R. Starling (U. of Leicester) Queries: palmer@lanl.gov Posted: 29 May 2008; 0:40 UT Subjects: X-ray, Gamma Ray, Soft Gamma-ray Repeaters (The following has also been submitted as GCN #7777, and is being resubmitted as an ATEL to bring it to the attention of the larger astronomical community.) Swift has detected the resumption of activity of Soft Gamma Repeater SGR 1627-41 after a 9.8-year long quiescent period. ?BAT detected the initial burst on 2008-05-28 at 08:21:43 UT, and a larger burst at 09:53:00. ?This was followed by a 'forest' of dozens of bursts extending at least to 10:25:54. ?The brightest burst seen thus far has a 15-50 keV flux of 550 times the Crab, averaged over a 0.128 second time interval. Following the BAT detection, Swift observed the source with XRT on 2008 May 28th, starting from 12:58:14 UT. This SGR was discovered in 1998 June when it emitted over 100 bursts clustered within 6 weeks (Kouveliotou et al. 1998, IAU Circ. 6944, 2; Woods et al. 1999, ApJ 519, L139); no further burst emission has been reported to date. Preliminary results, based on the first 2 ks XRT observation, found a persistent and relatively constant X-ray source with a count rate of 0.06 +/- 0.01 cts/s at a position RA, Dec = 16 35 51.9, -47 35 23.0 (J2000) with an uncertainty of 4.1 arcsec (radius, 90% confidence level). This position is consistent with the Chandra coordinates of the SGR (Wachter et al. 2004, ApJ 615, 887). The paucity of detected photons did not allow us to carry out a sensitive search for coherent pulsations (upper limits > 100% pulsed fraction at 3 sigma c.l.). A single absorbed black body model fits well the spectrum with nH=6.8x10^22 cm^-2 ?and kT=0.8 keV (Mereghetti et al. 2006, A&A 450, 759). The observed flux is 6.5x10^-12 erg/cm2/s (unabsorbed: 7.3x10^-11). This persistent luminosity is the highest ever recorded from this source (and a factor ~50 higher than the September 2004 XMM-Newton values; Mereghetti et al. 2006). Analysis of data from this burst is continuing, and will be reported in later circulars. A plot of the BAT light curve for the forest can be seen at http://gcn.gsfc.nasa .gov/gcn/other/SGR1627-41_timeline_2008.png. The timeline of the previous outbursts can be seen at http://gcn.gsfc.nasa.gov/gcn/ot her/SGR1627-41_timeline.gif. We thank the Swift Operations Duty Scientist and Flight Operations Team for performing a rapid ToO. ///////////////////////////////////////////////////////////////////// ATEL #1549 ATEL #1549 Title: RXTE Observations of Renewed Burst Activity from SGR 1627-41 Author: P.M. Woods (Dynetics/NSSTC), C. Kouveliotou (MSFC/NSSTC), E. Gogus (Sabanci Univ.), K. Hurley (UC-Berkeley), and J. Tomsick (UC-Berkeley) Queries: Peter.Woods@dynetics.com Posted: 29 May 2008; 12:31 UT Subjects: X-ray, Gamma Ray, Neutron Stars, Soft Gamma-ray Repeaters Following the Swift detection of the reactivation of SGR 1627-41 (Palmer et al. ATEL 1548 and GCN 7777), we searched serendipitous RXTE observations of the region targeting the black-hole transient 4U 1630-47. The 1 degree field-of-view of the PCA includes 4U 1630-47 and SGR 1627-41. We found no evidence for burst activity in 3 observations of the region between 2008 May 25 and 2008 May 27. During an RXTE observation of the region on 2008 May 28 (93702-01-14-01), we detect at least 8 bursts in a 1600 s exposure. The temporal and spectral properties of these bursts resemble those of SGR 1627-41. In particular, the bursts show rise times of ~10-100 ms and significantly slower fall times with total durations of 0.2-0.5 s. Some of the time histories exhibit double-peaked morphologies commonly seen from SGRs. The energy spectra are well characterized by a 4 keV blackbody in the PCA band (2-20 keV) where we have assumed a column density of 9x10^22 cm^-2 based upon modeling of the persistent emission (Kouveliotou et al. 2003). The peak luminosities of the eight bursts were on average 10^39 ergs/s for a distance of 11 kpc (Corbel et al. 1999). The brightest burst at 30103.9 SOD UT saturated the PCA having a peak luminosity of at least 10^40 ergs/s. We note that the spin period of this SGR has not yet been positively identified. Due to the poor signal-to-noise ratio during this observation, the limit on coherent pulsations from SGR 1627-41 for these data is not constraining. Follow-up ToO observations with RXTE and Chandra are planned for the next week. Daily observations of 4U 1630-47 with RXTE will also continue.