//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9133 SUBJECT: GRB 090417: Swift detection of a short burst DATE: 09/04/17 13:37:57 GMT FROM: Scott Barthelmy at NASA/GSFC V. Mangano (INAF-IASFPA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (MSSL), C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC), J. P. Osborne (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), M. Perri (ASDC), P. Romano (INAF-IASFPA), B. A. Rowlinson (U Leicester), B. Sbarufatti (INAF-IASFPA), M. C. Stroh (PSU), T. N. Ukwatta (GSFC/GWU), L. Vetere (PSU) and H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team: At 13:17:23 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 090417 (trigger=349447). Swift did not slew immediately due to a Sun constraint. The BAT on-board calculated location is RA, Dec 34.995, -7.181 which is RA(J2000) = 02h 19m 59s Dec(J2000) = -07d 10' 51" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 0.1 sec. The peak count rate was ~3200 counts/sec (15-350 keV), at ~0 sec after the trigger. Due to an observing constraint, Swift cannot slew to the BAT position. There will thus be no XRT or UVOT data for this trigger. This location will not come out of constraint until 02 Jun 2009. Burst Advocate for this burst is V. Mangano (vanessa AT ifc.inaf.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9134 SUBJECT: GRB 090417: 2MASS galaxy within BAT Localization DATE: 09/04/17 14:11:21 GMT FROM: Derek Fox at PSU D. B. Fox (Penn State) reports: "I note the presence of a bright (J_tot=13.4 mag) galaxy, 2MASX J02194771-0712008, within the BAT localization region of the Swift-detected short burst GRB 090417 (Mangano et al., GCN 9133). Considering the average sky density of 2MASS extended source catalog objects of this magnitude or brighter, the presence of such a galaxy within a region of 3-arcmin radius is suggestive at roughly 97%-confidence." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9136 SUBJECT: GRB 090417A: nearby galaxy redshift DATE: 09/04/17 16:27:39 GMT FROM: Nial Tanvir at IofA U.Cambridge P. T. O'Brien and N. R. Tanvir (U. Leicester) report: We note that the bright 2MASS galaxy at the edge of the BAT error circle, pointed out by Fox (GCN 9134), has a spectrum measured as part of the 6dF survey, which gives a redshift of z=0.088. This corresponds to a luminosity distance of about 400 Mpc in standard cosmology, which would be very large for an SGR giant flare, but quite plausible for a short-GRB comparable in luminosity to several others which have been seen at moderate redshifts. The spectrum can be seen at the following link: http://www-wfau.roe.ac.uk/6dFGS/cgi-bin/show.cgi?release=dr3&name=g0219477-071201&tid=-1&specid=123101 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9137 SUBJECT: GRB 090417A: Early-type nature of the putative host DATE: 09/04/17 17:35:29 GMT FROM: Josh Bloom at UC Berkeley J. S. Bloom (UC Berkeley), D. Fox (PSU), N. R. Tanvir, P. T. O'Brien (U. Leicester), William Lee (UNAM), J. X. Prochaska (UCO/Lick) report: We further note that the galaxy possibly associated (Fox GCN 9134) with GRB 090417A (Mangano et al., GCN 9133) appears both visually and spectrally to be of an early-type (smooth morphology, prominent Ca H&K). In the 6df spectrum (O'Brien & Tanvir, GCN 9136), there is some low-level Hα emission apparent suggesting some low-level star- formation. However no other Balmer lines appear prominently detected and there is no apparent [OIII] or [OII] as seen in the host galaxies of essentially all long-soft GRB (LSB) hosts. Without a detailed analysis, we classify this galaxy as a S0/lenticular or (more likely) an elliptical. Given the connection of several other SHBs to ellipticals at moderate redshift, we feel this identification can be taken as weak observational support for a connection between this galaxy and 090417A and further suggests that the burst was unlikely to be due to an SGR flare-type event (O'Brien & Tanvir, GCN 9136). The fact that the galaxy is at the edge of the BAT error circle does not necessarily argue against it being the host: the offset from the center of the circle, which amounts to ~320 kpc at this redshift, is certainly within the range of plausible natal kicks of a compact binary progenitor (~1 Gyr merger time for a 500 km/s kick). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9138 SUBJECT: GRB 090417A: Swift-BAT refined analysis DATE: 09/04/17 19:50:47 GMT FROM: Scott Barthelmy at NASA/GSFC W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), V. Mangano (INAF-IASFPA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-119 to T+261 sec from recent telemetry downlinks, we report further analysis of BAT GRB 090417A (trigger #349447) (Mangano, et al., GCN Circ. 9133). The BAT ground-calculated position is RA, Dec = 34.993, -7.141 deg which is RA(J2000) = 02h 19m 58.3s Dec(J2000) = -07d 08' 28.9" with an uncertainty of 2.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 30%. The mask-weighted light curve shows a single peak starting at T-0.06 sec, peaking at T+0.04 sec, and ending at T+0.09 sec. There appears to be no extended emmission out to T+55 sec, at which point the burst location went out of the BAT FOV during a planned target slew. T90 (15-350 keV) is 0.072 +- 0.018 sec (estimated error including systematics). The time-averaged spectrum from T-0.0 to T+0.1 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index -0.65 +- 2.11, and Epeak of 40.3 +- 12.7 keV (chi squared 67.41 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 1.9 +- 0.5 x 10^-8 erg/cm2 and the 1-sec peak flux measured from T-0.46 sec in the 15-150 keV band is 3.6 +- 1.0 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.99 +- 0.36 (chi squared 77.85 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/349447/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9160 SUBJECT: VLA observations of short burst GRB 090417A DATE: 09/04/19 13:23:35 GMT FROM: Poonam Chandra at U Virginia/NRAO P. Chandra (RMC) and D. A. Frail (NRAO) report on behalf of a larger collaboration: "We have used the Very Large Array (VLA) to image a field centered on the 2MASS galaxy suggested by Fox (GCN #9134) to be a possible host of the short duration burst 090417A (GCN # 9133, 9138). The VLA observed the burst at a frequency of 8.46 GHz on two epochs, April 17.92 UT and April 18.90 UT. Within a radius of 1.5 arcmin around the 2MASS galaxy there are no radio sources detected at either epoch to a 4-sigma limit of 104 uJy and 84 uJy, respectively. No further observations are planned. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc."