//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9135 SUBJECT: GRB 090417B: Swift detection of a burst DATE: 09/04/17 15:41:13 GMT FROM: Scott Barthelmy at NASA/GSFC B. Sbarufatti (INAF-IASFPA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), P.A. Curran (MSSL-UCL), P. A. Evans (U Leicester), O. Godet (U Leicester), 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), V. Mangano (INAF-IASFPA), J. Mao (INAF-OAB), R. Margutti (Univ Bicocca&OAB), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), P. Romano (INAF-IASFPA), B. A. Rowlinson (U Leicester), M. H. Siegel (PSU), M. Stamatikos (NASA/ORAU) and T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team: At 15:20:03 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 090417B (trigger=349450). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 209.706, +47.000 which is RA(J2000) = 13h 58m 49s Dec(J2000) = +47d 00' 01" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The TDRSS BAT light does not show much for this 320-sec image trigger (as is typical for image triggers). The XRT began observing the field at 15:26:30.4 UT, 387.0 seconds after the BAT trigger. XRT found a bright, uncatalogued and fading X-ray source located at RA, Dec 209.6931, +47.0170 which is equivalent to: RA(J2000) = 13h 58m 46.34s Dec(J2000) = +47d 01' 01.2" with an uncertainty of 5.0 arcseconds (radius, 90% containment). This location is 68 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 2.77e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 395 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The 3-sigma upper limit is white = 20.1 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02. Burst Advocate for this burst is B. Sbarufatti (sbarufatti 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: 9139 SUBJECT: GRB 090417B: Swift-BAT refined analysis DATE: 09/04/17 23:31:58 GMT FROM: Scott Barthelmy at NASA/GSFC J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), B. Sbarufatti (INAF-IASFPA), J. Tueller (GSFC), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from recent telemetry downlinks, we report further analysis of BAT GRB 090417B (trigger #349450) (Sbarufatti, et al., GCN Circ. 9135). The BAT ground-calculated position is RA, Dec = 209.624, 46.954 deg, which is RA(J2000) = 13h 58m 29.7s Dec(J2000) = +46d 57' 14.1" with an uncertainty of 4.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 94%. The mask-weighted light curve shows that this burst started before T-200 sec (where we start collecting event data on each trigger), slowly rises to a peak around T+400 sec and slowly decreases out past T+950 sec (where we stop processing the data). T90 (15-350 keV) is greater than 260 sec. The time-averaged spectrum from T+278.7 to T+617.1 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.85 +- 0.14. The fluence in the 15-150 keV band is 2.3 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+434.93 sec in the 15-150 keV band is 0.3 +- 0.1 ph/cm2/sec. 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/349450/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9140 SUBJECT: GRB090417B: optical observations DATE: 09/04/18 00:23:39 GMT FROM: Johan U. Fynbo at U.Copenhagen J. P. U. Fynbo, D. Malesani, Jens Hjorth (DARK/NBI), E. Leitet, Staffan Linne (Uppsala), Thomas A. Ottosen (NOT), P. Jakobsson (Univ. Iceland), report on behalf of a larger collaboration: We observed the field of GRB 090417B (Sbarufatti et al., GCN 9135) with the NOT equipped with ALFOSC. Observations were carried out in the B, R and i bands. Inside the revised XRT error circle, we find a single source detected in all three bands, with approximate magnitude R=21.3 (at mean time Apr 17.966, 7.84 hr after the GRB). The source is also visible in the SDSS and classified as a galaxy. Photometry reveals that the object has approximately the same brightness as in the SDSS (in the R band). In the NOT images the object also appears extended. The source is thus unlikely to be the afterglow of GRB 090417B, although it may be its host galaxy. We acknowledge excellent support from the NOT staff and observer. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9141 SUBJECT: GRB 090417B: optical observations DATE: 09/04/18 01:25:33 GMT FROM: Igor Volkov at Asro.Inst.Slovak Acad.Sciences On 2009 April 17 I observed the field of GRB 090417B (Sbarufatti et al. GCN Circ. 9135) with the 0.5m reflector and ST-10XME CCD camera of Stara Lesna (Slovak Republic) observatory. I have got 11 frames in standard Rc system, starting at 22:10:05 UT, 23332s after the alert. In my coadded frame (total exposition 930s)it was not possible to detect a single source inside the refined XRT error box (Sbarufatti et al. GCN Circ. 9135) with S/N rate more than 5, which corresponds to limiting magnitude Rc >19.9. The time of the middle of the sequence was 22:18:00 UT. GSC2.3 catalog was used for flux calibration. Igor Volkov, visiting astronomer of Astronomical Institute of the Slovak Academy of Sciences, 059 60 Tatranska Lomnica, Slovak Republic; Sternberg Astronomical Institute, 119992 Moscow, Universitetskij pr.13; e-mail: volkov@ta3.sk, imv@sai.msu.ru //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9142 SUBJECT: GRB090417B: Xinglong TNT optical upper limit DATE: 09/04/18 05:03:56 GMT FROM: L.P. Xin at NAOC L. P. Xin, X. F. Wang, W. K. Zheng, Y. L. Qiu, J. Y. Wei, J. Wang, J. S. Deng, Y. Urata and J. Y. Hu on behalf of EAFON report: We have observed GRB 090417B (Sbarufatti et al., GCN 9135) with Xinglong TNT telescope from Apr.17,15:34:38(UT), 14.5 min after the burst. The weather was cloudy. After combined white and R band images, no new source was found in our combined images. The 3 sigma upper limits derived from USNO-B1.0 R2 magnitudes were shown as following: -------------------------------------------------------- MeanTime exposure Band Mag UpperLimit? coadded? -------------------------------------------------------- 16.5min 8*40s white 20.1 yes yes 1.63hr 29*300s R 21.6 yes yes ------------------------------------------------------- We also notice that in the location of XRT error circle, a extended object was likely to be present, as found by Fynbo et al (GCN 9140). However, the S/N is very low that we could not make sure. This message may be cited. For more information about Xinglong GRBs Follow-up observations, please visit the website: http://www.xinglong-naoc.org/grb/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9143 SUBJECT: GRB 090417B: MITSuME Okayama optical upper limits DATE: 09/04/18 06:21:01 GMT FROM: Michitoshi Yoshida at Okayama Astrophysical Obs D. Kuroda, M. Yoshida, K. Yanagisawa, Y. Shimizu, S. Nagayama, H. Toda (OAO, NAOJ) and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the field of GRB 090417B (Sbarufatti et al. GCN 9135) with optical three color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory. We started the observation at 15:29:29 UT, 566s after the burst. There is no point source brighter than 20 mag within the XRT error circle (Cummings et al. GCN 9139) in our 5940 sec exposure frames. 3-sigma upper limits to our observation are listed below. We used GSC2.3 catalog for flux calibration. Mid-UT Td EXP-T g' Rc Ic ----------------------------------------------------------- 15:34:43 880s 540s (9x60s) >19.2 >18.8 >18.4 15:44:55 1492s 1560s (24x60s) >19.9 >19.6 >19.1 15:59:37 2374s 3000s (50x60s) >20.2 >19.9 >19.4 16:29:42 4179s 5940s (99x60s) >20.3 >20.0 >19.5 ----------------------------------------------------------- //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9144 SUBJECT: GRB 090417B: Liverpool Telescope observations DATE: 09/04/18 09:13:41 GMT FROM: Cristiano Guidorzi at Ferrara U,Italy C. Guidorzi (U. Ferrara), R. Smith, C.G. Mundell (Liverpool JMU), A. Gomboc (U. Ljubljana), P. O'Brien, N. Tanvir (U. Leicester) on behalf of a large collaboration report: On 2009 April 18 at 03:10:50 UT we observed the Swift GRB 090417B (Sbarufatti et al., GCN Circ. 9135) with the Liverpool Telescope using the SDDS-R filter. From a 6x300 s frame, inside the revised XRT error circle we clearly detect the SDSS galaxy already mentioned by Fynbo et al. (GCN Circ. 9140). At a mid epoch of 12.10 hrs post burst we estimate its magnitude of r'=21.9 +/- 0.3, calibrated with respect to nearby SDSS stars. This value is consistent with that reported in the SDSS catalogue of 21.6 mag. We therefore conclude that this source is not the afterglow of GRB 090417B, while it could possibly be its host galaxy, as already suggested by Fynbo et al. (GCN Circ. 9140). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9145 SUBJECT: GRB 090417B: Subaru NIR Observations DATE: 09/04/18 09:53:27 GMT FROM: Nobuyuki Kawai at Tokyo Tech K. Aoki, I. Tanaka, F. Nakata (Subaru Telescope), K. Ohta, S. Yuma (Kyoto U), and N. Kawai (Tokyo Tech) report on behalf of the Subaru GRB team: We observed the field of GRB 090417B (Sbarufatti et al. GCN 9135) with MOIRCS on Subaru Telescope in J band Ks bands under a cirrus condition. The observing period is from 05:00 UT to 07:45 UT on April 18th, about 15 hours after the burst. In the XRT error circle, we detected the object reported by Fynbo et al. (GCN 9140). Roughly estimated J and Ks magnitudes of this object relative to a nearby 2MASS star are 20.0 mag and 18.5 mag (Vega), respectively. The object seems to be point-like under the seeing condition of 0."7, though the S/N is not so good to be definitive. No other sources are found in the error circle. The GRB may be a dusty GRB in the galaxy seen in the SDSS image, or might be a high redshift GRB that appeared far behind the galaxy, or intrinsically very faint. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9153 SUBJECT: GRB 090417B: Swift-BAT further refined analysis DATE: 09/04/18 15:31:19 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), D. M. Palmer (LANL), B. Sbarufatti (INAF-IASFPA) (for the Swift-BAT team): Continuing the analysis for BAT GRB 090417B (trigger #349450) (Cummings, GCN Circ 9139) using more downlinked data, we report that this burst is very long. The revised mask-weighted light curve starts before T-200 sec (where we start collecting event data on each trigger), slowly rises to a peak around T+400 sec and slowly decreases to a minumum around T+1100 sec, then increases to a second maximum around T+1650 sec, and then decreases again with continuing emission past T+2100 sec (where the data stops). The amplitudes of the two peaks are 0.09 +- 0.01 and 0.060 +- 0.006 ph/cm2/sec, resp. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9155 SUBJECT: GRB 090417B: Swift-XRT refined analysis DATE: 09/04/18 16:55:25 GMT FROM: Boris Sbarufatti at INAF-IASF-Pa Sbarufatti B., Mangano V. (INAF-IASFPA) report on behalf of the Swift Team: We have analysed the first six orbits of Swift-XRT data obtained from GRB 090417B (trigger 349450; Sbarufatti, et al., GCN Circ. 9135), comprising 1456 s taken in Windowed Timing (WT) mode, from T+393 s to T+2.0 ks, and a total exposure of 9.2 ks in Photon Counting (PC) mode divided in 192 s from T+1.1 ks to T+1.3 ks and 9.0 ks from T+5.4 ks to the end of the observation at T+30 ks. Using 6972 s of XRT Photon Counting mode data and 9 UVOT images, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching to the USNO-B1 catalogue): RA, Dec = 209.6942, 47.0182 which is equivalent to: RA (J2000): 13 58 46.62 Dec (J2000): +47 01 05.4 with an uncertainty of 1.4 arcsec (90% confidence). This position lies 4.8 arcmin from the BAT refined position, outside the quoted error circle (Cummings, et al., GCN circ. 9139). The 0.3-10 keV X-ray light curve of the first orbit is dominated by flaring activity, with 3 major peaks at ~T+530, ~T+1410 s and ~T+1560 s respectively. From the second orbit on the light-curve is decaying according to a power-law with slope -1.21+/-0.05. If decaying at this rate, the afterglow will reach a count-rate of 1.98E-2 counts/s at T+48h. The average WT spectrum of the first orbit is best fitted by an absorbed power-law model with a high energy cutoff. The best fit parameters are photon index 0.40+/-0.17, cutoff energy 3.1+/-0.4 keV and NH (9.2+/-0.6)E21 cm^-2, in large excess with respect to the galactic value 1.6E20 cm^-2 (Kalberla et al. 2005). The average observed(unabsorbed) flux in the 0.3-10 keV band is 1.6(2.1)E-9 ergs cm^-2 s^-1. The average spectrum of the large double peaked flare between T+1.3 ks and T+2.0 ks is also fitted by an absorbed power-law model with a high energy cutoff with best fit parameters photon index 0.46+/-0.2, cutoff energy 3.2+/-0.5 and NH (9.5+/-0.7)E21 cm^-2. The average PC spectrum in the T+5.4 ks - T+30 ks interval is well fitted by an absorbed power-law with photon index 2.0+/-0.1 and NH (9.6+/-0.10E21 cm^-2. The average observed(unabsorbed) flux in the 0.3-10 keV band is 2.8(5.6)E-11 ergs cm^-2 s^-1. The count-rate to flux conversion factor is 1.0E-10. All quoted errors are at 90% confidence level. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00349450. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9156 SUBJECT: GRB 090417B: Galaxy redshift DATE: 09/04/18 17:49:52 GMT FROM: Edo Berger at Harvard E. Berger (Harvard) and D.B. Fox (PSU) report: "We obtained spectroscopic observations of the SDSS galaxy located inside the XRT error circle of GRB 090417B (GCNs 9153, 9155, 9140) with GMOS on the Gemini-North telescope. In a combined 1800 sec spectrum we detect emission lines corresponding to [OII]3727, [OIII]5006, and H-alpha at a redshift of z=0.345. At this redshift the observed fluence of the burst (2.3e-6 erg/cm^2; GCN 9139) translates to an isotropic-equivalent energy of 9e50 erg." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9158 SUBJECT: GRB 090417B: Gemini imaging DATE: 09/04/18 18:54:50 GMT FROM: Edo Berger at Harvard E. Berger (Harvard), D.B. Fox (PSU), and N. Tanvir (Leicester) report: "In addition to the spectroscopic observations described in GCN 9156, we also imaged the field of GRB 090417B with GMOS in the griz filters starting on 2008 April 18.38 (17.7 hours after the burst). A total of 360 sec were obtained in gri, and a total of 540 sec was obtained in z. We find the following magnitudes for the SDSS galaxy coincident with the XRT afterglow position: g = 22.47+/-0.16 mag (SDSS: 23.0+/-0.5 mag) r = 21.62+/-0.10 mag (SDSS: 21.62+/-0.16 mag) i = 21.31+/-0.12 mag (SDSS: 21.41+/-0.09 mag) z = 21.49+/-0.30 mag (SDSS: 20.78+/-0.25 mag) Thus, we find no evidence for brightening compared to the SDSS archival magnitudes." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9165 SUBJECT: VLA radio upper limit on GRB 090417B DATE: 09/04/19 23:26:11 GMT FROM: Poonam Chandra at U Virginia/NRAO Poonam Chandra (RMC) and Dale A. Frail (NRAO) report on behalf of a larger collaboration: "We used the Very Large Array to observe the field of view toward GRB 090417B (GCN 9135) at a frequency of 8.46 GHz on 2009 Apr. 19.37 UT. The GRB radio afterglow is undetected within the Swift-XRt error circle (GCN 9155). We place the three-sigma upper limit of 120 uJy on the GRB afterglow. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9173 SUBJECT: GRB 090417B Correction to the BAT refined analysis position DATE: 09/04/20 17:04:26 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift J. R. Cummings (GSFC/UMBC), S. D. Barthelmy, H. A. Krimm (GSFC/USRA), B. Sbarufatti(INAF-IASFPA), P.A. Evans (U. Leicester) on behalf of the Swift team We wish to make a correction to the reported analysis of the extremely long-duration burst GRB 090417B (GCN circ #9135, Sbarufatti et al.). The position in the BAT refined-analysis circular (GCN circ #9139, Cummings et al.) was based on the results of an automated script, which was unable to find the optimum imaging interval due to the unusual length of this burst. Thus the reported position was not the best BAT ground-calculated position. The best position is RA, Dec 209.687 +47.015, which is: RA (J2000) 13h 58m 44.8s Dec (J2000) 47d 00m 55s with an error radius of ~1 arcmin. This position is 0.35 arcmin from the XRT refined position (GCN circ #9155, Sbarufatti et al.). We are grateful to those who noticed the discrepancy, and regret any confusion resulting from this error. Any corrections to other BAT refined-analysis items (which are expected to be slight), such as to the spectral index, will appear in the final Swift Team report on this burst. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9174 SUBJECT: GRB 090417B: Swift/UVOT Upper Limits DATE: 09/04/20 19:46:26 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/GSFC/USRA) and B. Sbarufatti (INAF-IASFPA) report on the behalf of the Swift UVOT team: The Swift/UVOT observed the field of GRB 090417B starting 378 s after the BAT trigger (Sbarufatti, et al., 2009, GCN Circ. 9135). Settled exposures started at T+395 s. We do not find any new source, relative to the DSS, USNO-B1.0, or 2MASS at the position of the XRT afterglow (Sbarufatti, et al. 2009, GCN Circ. 9155). Preliminary 3-sigma upper limits for detecting a source in the white finding chart, and the co-added images, using a 2.5 arcsecond radius circular aperture, are Filter T_start T_stop Exp(s) Mag -------------------------------------------- white (fc) 395 545 147 >21.7 v 552 13,098 1237 >21.3 b 651 19,457 862 >21.9 u 1300 25,241 1376 >22.0 uvw1 601 25,174 2300 >22.2 uvm2 750 24,268 1878 >21.8 uvw2 700 29,604 1331 >22.0 white 395 7823 841 >22.6 -------------------------------------------- The quoted upper limits have not been corrected for the expected Galactic extinction along the line of sight corresponding to a reddening of E_{B-V} = 0.02 mag (Schlegel, et al., 1998, ApJS, 500, 525). All photometry is on the UVOT photometry system described in Poole et al. (2008, MNRAS, 383, 627). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9180 SUBJECT: GRB 090417B: Optical observation DATE: 09/04/21 04:28:00 GMT FROM: Rupak Roy at ARIES Brajesh Kumar, Rupak Roy, Brijesh Kumar and S. B. Pandey (ARIES, NainiTal, India, on behalf of larger Indian GRB collaboration). We observed swift GRB 090417B (GCN 9135) using 104 cm Sampurnanand optical telescope at A.R.I.E.S. Nainital on 17th April, 2009 at 16.244 hrs UT, under good sky conditions using 2k*2k CCD detector. No afterglow candidate was found in our co-added R_c band image (exp time = 5*300 sec) within the error region of BAT. Photometry of the stacked frame poses an upper limit of ~ 21 mag, in comparison to nearby USNO-B1 stars.