THIS FILE CONTAINS CIRCULARS FOR BOTH 'A' and 'B' BURSTS. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3264 SUBJECT: Swift BAT/XRT Detection of GRB 050416 DATE: 05/04/16 11:50:53 GMT FROM: Takanori Sakamoto at NASA/GSFC T. Sakamoto (GSFC/NRC), L. Barbier (GSFC), S. Barthelmy (GSFC), D. Burrows (PSU), M. Chester (PSU), J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (UMD), J. Kennea (PSU) , H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), G. Sato (ISAS), M. Suzuki (Saitama), M. Tripicco (GSFC-SSAI), J. Tueller (GSFC), D. Burrows (PSU), on behalf of the Swift team: At 11:04:44.5 UT, the Swift Burst Alert Telescope (BAT) triggered and located on-board GRB050416 (trigger #114753). The BAT on-board calculated location is RA, dec 188.478, 21.043 (J2000) with an uncertainty of 3.00 arcmin (radius, 3-sigma, including estimated systematic uncertainty). The BAT light curve shows double structures with a duration of about three seconds. The peak count rate measured by BAT was about 3000 counts/sec in the 15 - 350 keV band. The burst signal is mostly seen in 15-50 keV. The XRT observed the target field at 11:06:12 UT and detected 17 counts in a single CCD frame, just under the number needed for a reliable on-board centroid. Initial indications based on the raw spectra and lightcurve transmitted via TDRSS suggest that there is a real X-ray source in the field. We will issue an update following the next ground station pass at 12:18 UT. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3265 SUBJECT: GRB050416: P60 Afterglow Candidate DATE: 05/04/16 12:06:54 GMT FROM: S. Bradley Cenko at Caltech S. Bradley Cenko and Derek B Fox report on behalf of the Caltech-NRAO- Carnegie GRB Collaboration: We have imaged the error circle of the Swift GRB050416 with the automated Palomar 60-inch Telescope. We find the presence of a bright, stationary source not present in the DSS at the location: RA: 12:33:54.6 Dec: +21:03:26.7 J2000.0 We tentatively identify this object as the afterglow of GRB050416 //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3266 SUBJECT: Confirmation of OT for GRB050416 DATE: 05/04/16 13:01:18 GMT FROM: Brian Schmidt at RSAA, ANU (MSSSO) Gemma Anderson, Marilena Salvo, Josh Rich and Brian P Schmidt (Australian National University) report on behalf of a larger collaboration "We observed a 6' region covering the BAT position of the SWIFT burst GRB 050416 using the ANU 2.3m telescope on April 12.51 UT in R band. The object identified by Cenko and Fox is mvisible and clearly has faded in comparison with their image. This indicate that this object is likely the afterglow of GRB 050416 //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3267 SUBJECT: GRB 050416: Radio observations DATE: 05/04/16 13:17:22 GMT FROM: Dale A. Frail at NRAO D. A. Frail (NRAO) and A. M. Soderberg (Caltech) report on behalf of the Caltech-NRAO-Carnegie GRB Collaboration: "We observed the field centered on the BAT position of the Swift burst GRB 050416 (GCN#3264) using the VLA at a frequency of 8.46 GHz and starting at 11:42 UT, about 37 minutes after the burst. There are no bright radio sources (> 260 microJy) within 1 arcminute of the BAT position. At the position of the afterglow candidate of Cenko and Fox (GCN#3265), the peak radio flux is 20 +/- 51 microJy. Further observations are planned." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3268 SUBJECT: GRB 050416: Swift XRT Position DATE: 05/04/16 13:55:53 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT J. A. Kennea, J. L. Racusin, D. N. Burrows (PSU), V. Mangano (IASF/Palermo), T. Sakamoto (GSFC/NRC), N. Gehrels (NASA/GSFC) report on behalf of the Swift XRT team: The Swift BAT instrument detected a GRB at 11:04:45 UT on 16th April 2005 (GCN Circ 3264). The observatory executed an automated slew to the BAT position and the XRT began taking data at 11:06:03 UT. The XRT was in Auto state but was not able to centroid on the afterglow due to low source brightness. From downlinked data we find a uncataloged fading X-ray source located at: RA(J2000) = 12:33:54.6, Dec(J2000) = +21:03:24. We estimate an uncertainty of about 5 arcseconds radius (90% containment). This position is 49 arcseconds from the BAT position reported in GCN 3264, and 2.7 arcseconds from the P60 optical afterglow candidate reported in GCN 3265. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3269 SUBJECT: GRB050416: P200 NIR Observations DATE: 05/04/16 14:58:48 GMT FROM: S. Bradley Cenko at Caltech S. Bradley Cenko, Derek B. Fox, and Avishay Gal-Yam (Caltech) report on behalf of the Caltech-NRAO-Carnegie GRB Collaboration: We have imaged the field of GRB050416 with the Wide-Field Infrared Camera (WIRC) mounted on the Palomar 200-inch Hale Telescope. Images were taken in Ks-band and began approximately 6 minutes after the burst. The afterglow candidate reported in GCN 3265 is clearly detected. The object fades by 0.8 mag from approximately 11:15 UT to 12:05 UT (10 - 50 minutes after the burst), confirming the results of Anderson et al. (GCN 3266). //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3270 SUBJECT: GRB 050416: KAIT observations DATE: 05/04/16 15:30:38 GMT FROM: Weidong Li at UC Berkeley KAIT/LOSS W. Li, R. Chornock, S. Jha, and A. V. Filippenko (University of California, Berkeley) report: "The Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory robotically observed Swift GRB 050416 (Trigger #114753; Sakamoto et al., GCN 3264). The first 3x15s R-band grid image started at 11:05:25 UT (40.5s after the burst), which did not detect the afterglow as observed by Cenko and Fox (GCN 3265) to a limiting magnitude of about 16.5 when compared to the USNO A2.0 catalog. Our subsequent images have varying exposure times from 15s to 360s, and were observed with R, I, V, and z filters. Due to the depth of the images, only a 60s I-band image started 11:12:09 UT (444.5s after the burst) has a marginal detection of the afterglow. Further analysis is in progress." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3271 SUBJECT: GRB 050416,optical observation DATE: 05/04/16 15:53:23 GMT FROM: Eri Sonoda at U of Miyazaki/Japan E.Sonoda,S.Maeno,Y.Tokunaga,M.Yamauchi (University of Miyazaki) "We have observed the field covering the error circle of GRB 050416 (GCN3264 ; Swift-BAT Trigger time is 11:04:57 UT) with the unfiltered CCD camera on the 30-cm telescope at University of Miyazaki. The observation was started 11:09:18 UT on Apr.16. After co-adding a set of 5 images (11:09:18 - 11:14:52 UT) of 30 sec exposures, we have compared with the USNO A2.0 catalog. Preliminary analysis shows there is no new source brighter than 16.7 mag. at the reported position by S.Bradley Cenko et al. (GCN3265) and J.A.Kennea et al.(GCN3268)." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3272 SUBJECT: GRB 050416: ART observations DATE: 05/04/16 16:09:24 GMT FROM: Ken ichi Torii at RIKEN K. Torii (Osaka U.) reports "The error region of GRB 050416 (Sakamoto, et al. GCN 3264) was observed with the ART 14 inch telescope. VRcIc imaging started at 11:05:36 UT (52s after trigger) and 60s exposure was repeated. As a result of the preliminary analyses, the optical afterglow (Cenko and Fox GCN 3265; Anderson, et al. GCN 3266) is not detected in our frames and the following upper limit is derived relative to USNO-A2.0 (R) magnitude. Start(UT) Magnitude Exposure 11:07:53 >16.6Rc 60s " //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3273 SUBJECT: GRB 050416: Swift-BAT refined analysis DATE: 05/04/16 16:25:32 GMT FROM: Takanori Sakamoto at NASA/GSFC T. Sakamoto (GSFC/NRC), L. Barbier (GSFC), S. Barthelmy (GSFC), J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), G. Sato (ISAS), M. Suzuki (Saitama), M. Tashiro (Saitama U.), J. Tueller (GSFC), on behalf of the Swift/BAT team: At 11:04:44.5 UT Swift-BAT detected GRB 050416 (trigger=114753) (GCN Circ 3264, Sakamoto et al.). The refined BAT ground position is (RA,Dec) = 188.490, 21.053, [deg; J2000] +- 3 arcmin, (95% containment). This is 0.7 arc minutes from the position determined by the XRT (GCN Circ 3268, Kennea, et al.). The BAT mask weighted light curve shows a single peak of about one second duration followed by a small bump. Most of the emission is in the 15-50 keV band. T90 (15-350 keV) is (2.4 +- 0.2) seconds (estimated error including systematics). The photon index of the spectrum is 2.9 +- 0.2. The fluences in the 15-50 keV band and in the 15-350 keV band are (2.8 +- 0.2) x 10^-7 erg/cm2 and (3.8 +- 0.4) x 10^-7 erg/cm2 respectively. The peak photon fluxes in the 15-50 keV band and in the 15-350 band are (4.4 + 0.8) ph/cm2/s and (4.8 +- 0.6) ph/cm2/s respectively. All the quoted errors are in 90% confidence level. The BAT team cautions that while there appears to be a deficit of counts below 20 keV, this is likely due to systematic errors in the response matrix being accentuated by the steep spectrum. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3274 SUBJECT: GRB050416: Maidanak optical observations DATE: 05/04/16 17:45:24 GMT FROM: Alexei Pozanenko at IKI, Moscow B. Kahharov, M. Ibrahimov, D. Sharapov (MAO), A.Pozanenko (IKI) V.Rumyantsev (CrAO), G.Beskin (SAO) on behalf of larger collaboration report: We observed the Swift GRB050416 (Sakamoto et al. GCN3264) with 1.5m telescope of the Maidanak Astronomical Observatory (MAO), Uzbekistan The observation started at (UT) 15:34 , April 16 in R and B bands. We found a source at the position afterglow (Cenko & Fox GCN3265). A preliminary R-photometry of first frames against of USNO-B1.0 Catalog is the following: Mean time Exposure Mag. (UT) (s) 15:44 3x300 20.85 +/- 0.12 Observation is continuing. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3275 SUBJECT: GRB050416: Refined Swift-XRT analysis DATE: 05/04/16 18:37:28 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT G. Cusumano, V. La Parola, T. Mineo, V. Mangano (IASF/Palermo), G. Chincarini, S. Campana, G. Tagliaferri, P. Romano, P. Giommi, M. Perri (INAF-OAB), M. Capalbi (ASDC), D. N. Burrows, J. A. Kennea (PSU), N. Gehrels (NASA/GSFC) We have analyzed the Swift-XRT data from the first orbit observation of GRB050416 (Sakamoto et al. 2005, GCN3264). The new refined coordinates are: RA(J2000) = 12:33:54.8 Dec(J2000) = +21:03:25.1 This position is 17.7 arcseconds from the BAT position given in GCN 3273 (Sakamoto et al. 2005) and 1.3 arcsec from the preliminary XRT position (GCN3268, Kennea et al. 2005). We estimate an uncertainty of 5 arcseconds radius (90% containment). The [0.2-10] keV light curve in Photon Counting (PC) mode starts ~90 seconds from the BAT trigger (T0). We clearly detect a rapidly fading source. The light curve can be fitted with a single power law with alpha= -0.6 +/- 0.3. A preliminary spectral fit to the PC data gives a spectral power law photon index of 2.02+/-0.21 in the [0.2-10] keV band, with a column density of (0.25+/-0.05)E22 cm^-2 (the Galactic line-of-sight absorption is 2.06E20 cm^-2). The average estimated unabsorbed 0.2-10 keV flux is 1.7E-11 erg cm^-2 s^-1. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3276 SUBJECT: GRB 050416: Swift/UVOT detection of afterglow emission DATE: 05/04/16 19:13:08 GMT FROM: Patricia Schady at MSSL/Swift P. Schady (MSSL), T. Sakamoto (GSFC/NRC), K. McGowan (MSSL), P. Boyd (GSFC/UMBC), P. Roming (PSU), J. Nousek (PSU), N. Gehrels (GSFC), on behalf of the Swift UVOT team. The Swift Ultra-Violet/Optical Telescope (UVOT) began settled observations of the field of GRB 050416 (Sakamoto et al; GCN 3264) at 11:05:49 UT, 65s after the BAT trigger. A comparison of the 100s finding chart in the V filter against the Digitized Sky Survey reverals a new source inside the XRT error circle at RA = 12 33 54.56 Dec = +21 03 27.73 and consistent with the P60 positition reported by Bradley Cenko & Fox (GCN 3265). The V band magnitude is V = 19.38. The magnitude is based on preliminary zero-points, measured in orbit and will require refinement with further calibration. Further detailed analysis is ongoing. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3279 SUBJECT: Swift-BAT detection of GRB 050416b DATE: 05/04/16 23:23:57 GMT FROM: Scott Barthelmy at NASA/GSFC D. Hullinger (UMD), L. Barbier, S. Barthelmy (GSFC), J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), M. Suzuki (Saitama), J. Tueller (GSFC) on behalf of the Swift-BAT team: At 22:35:54.11 UT Swift-BAT triggered on burst GRB 050416b (trigger=114797). The BAT flight position is RA,Dec=133.853,+11.173 (J2000). We note this is 17 deg from the Moon, hence the s/c did not slew because of the Moon observing constraint. The burst was 53 deg off the BAT bore sight. The lightcurve shows a narrow peak with a total burst duration of ~5 sec (T90=~3sec in 15-350 keV). //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3280 SUBJECT: GRB 050416: Swift/UVOT refined analysis DATE: 05/04/17 00:22:59 GMT FROM: Patricia Schady at MSSL/Swift P. Schady (MSSL), T. Sakamoto (GSFC/NRC), K. McGowan (MSSL), P. Boyd (GSFC/UMBC), P. Roming (PSU), J. Nousek (PSU), N. Gehrels (GSFC), on behalf of the Swift UVOT team. Starting with the data taken ~207s after the BAT trigger (Sakamoto et al., GCN 3264) we have co-added the early time data of GRB 050416 in each of the Ultra-Violet/Optical Telescope (UVOT) U, B, and V bands. The co-added images are made up of 9 x 10s exposures. A source is detected at the position of the afterglow (Cenko & Fox, GCN 3265) in the U and B band with magnitudes U = 19.34 +/- 0.2 and B = 19.85 +/- 0.2. No source is detected in the V co-added image down to a 5-sigma limiting magnitude V > 19.57. There is ~173s difference between the start of the finding chart exposure, in which a source was detected (Schady et al., 3276) and the co-added image. The magnitudes are based on preliminary zero-points, measured in orbit and will require refinement with further calibration. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3281 SUBJECT: GRB050416B: IR observations DATE: 05/04/17 02:38:02 GMT FROM: Silvia Piranomonte at OAR S. Piranomonte, A. Melandri, L.A. Antonelli, S. Covino, F.M. Zerbi, G. Chincarini, M. Rodono', G. Tosti, P. Conconi, G. Cutispoto, E. Molinari, L. Nicastro, E. Palazzi, E. Meurs, P. Goldoni, on behalf of the REM/ROSS Team report: "The REM telescope at the La Silla Observatory (ESO) is observing the field of GRB 050416B (BAT Trigger #114797). Observations started just after the sunset in La Silla on Apr. 17 00:01:17 UT about 1.1hr after the burst. Preliminary analysis of the first frames reveal no new sources in the BAT error circle (Hullinger et al., GCN 3279) approximately down to the 2MASS limit in the J, H and Ks bands. Observations and further analyses are going on. This message may be cited." ------------------------------------------------- This mail sent through IMP: http://horde.org/imp/ //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3282 SUBJECT: GRB 050416b: LCO observations DATE: 05/04/17 02:54:02 GMT FROM: Edo Berger at Carnegie Obs E. Berger, J. Mulchaey (Carnegie Observatories), N. Morrell, and W. Krzeminski (LCO) report: "We imaged the BAT error circle of GRB 050416b (GCN 3279) with the Swope 40-inch telescope (r-band) and the du Pont 100-inch telescope (I-band) at LCO starting on 2005, April 17.001 and 17.002 UT, respectively (86 and 114 min after the burst). We also obtained a 5-minute image with IMACS on the Magellan/Baade telescope in R-band. A comparison to DSS reveals no new sources to the depth of the survey in any of our images." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3283 SUBJECT: GRB 050416b: LCO observations DATE: 05/04/17 03:10:08 GMT FROM: Edo Berger at Carnegie Obs E. Berger, J. Mulchaey (Carnegie Observatories), N. Morrell, and W. Krzeminski (LCO) report: "We imaged the BAT error circle of GRB 050416b (GCN 3279) with the Swope 40-inch telescope (r-band) and the du Pont 100-inch telescope (I-band) at LCO starting on 2005, April 17.001 and 17.002 UT, respectively (86 and 114 min after the burst). We also obtained a 5-minute image with IMACS on the Magellan/Baade telescope in R-band. A comparison to DSS reveals no new sources to the depth of the survey in any of our images." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3284 SUBJECT: GRB 050416b: Swift-BAT refined analysis DATE: 05/04/17 03:26:08 GMT FROM: Takanori Sakamoto at NASA/GSFC G. Sato (ISAS), L. Barbier, S. Barthelmy (GSFC), J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), M. Suzuki (Saitama), J. Tueller (GSFC) on behalf of the Swift-BAT team: At 22:35:54.1 UT Swift-BAT detected GRB 050416b (trigger=114797) (GCN Circ 3279, Hullinger et al.). The refined BAT ground position is (RA,Dec) = 133.854, 11.182, [deg; J2000] +- 3 arcmin, (95% containment). The partial coding fraction was 16%. The moon is moving towards the position of the GRB, and Swift will not be able to observe for several days because of the spacecraft moon angle constraint. The BAT mask weighted light curve shows a FRED-like structure. T90 (15-350 keV) is (5.4 +- 0.9) seconds (estimated error including systematics). The time-averaged spectrum is well fitted in a simple power-law model. The photon index is 1.5 +- 0.2. The fluence in the 15-350 keV band is (2.1 +- 0.3) x 10^-6 erg/cm2. The peak photon flux in the 15-350 band is (7.9 +- 0.7) ph/cm2/s. The quoted errors are at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3285 SUBJECT: GRB 050416B: optical observations DATE: 05/04/17 03:42:11 GMT FROM: Alberto Castro-Tirado at LAEFF-INTA M. Jelinek, A. de Ugarte Postigo (IAA-CSIC Granada), P. Kubanek (ASU-CAS Ondrejov), T. J. Mateo Sanguino (Univ. de Huelva), S. Castillo, J. Gorosabel, S.Guziy and A. J. Castro-Tirado (IAA-CSIC), report: "Following the detection by SWIFT/BAT of GRB 050416B (Hullinger et al., GCN 3279), the 0.6m BOOTES-IR telescope at IAA's Observatorio de Sierra Nevada responded automatically at 23:13 UT (i.e. 38 minutes after the event). Although we are still testing the telescope during the commissioning phase, and the near-IR camera is not yet installed, an optical camera was available. A co-addition of first 20 R-band images taken at that particular instrument reveals no optical counterpart in the SWIFT/BAT error box down to R = 19. The instrument sensitivity was highly compromised due to the presence of the nearby moon. Additional info on BOOTES-IR can be found at www.iaa.csic.es/BOOTES-IR.html." This message can be quoted. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3286 SUBJECT: GRB 050416 : optical observation at Xinglong observatory DATE: 05/04/17 08:56:06 GMT FROM: Yuji Urata at RIKEN Y. Qiu, C.L. Lu (BAO), Y.Q. Lou (THCA), K.Y. Huang (NCU), Y. Urata (RIKEN) on behalf of EAFON report " We have imaged the GRB 050416 optical afterglow position (Bradley et al, GCN 3265) using 0.8-m telescope at XingLong Observatory, China. The observations started at 18.65 UT (~ 7.57 hours after the burst). Due to the bad weather condition (seeing ~ 4"), the limiting magnitude of our R band co-added image is ~ 18.6 compared with USNOB1.0 stars. No new source was detected under the limiting magnitude. This message may be cited." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3287 SUBJECT: GRB 050416: Mitsume optical observation DATE: 05/04/17 13:53:02 GMT FROM: Nobuyuki Kawai at Tokyo Tech K. Yanagisawa (OAO/NAO), H. Toda, and N. Kawai (Tokyo Tech) report on behalf of the Mitsume Collaboration: "The field of GRB050416 (Sakamoto et al.; GCN 3264) was observed by the 3-color Mitsume 50cm Telescope at Okayama, Japan starting at 13:27 (UT). With the first 60 min exposure, we did not detect a source brighter than V=18.0, R=19.6, and I=19.0 at the position of the afterglow reported by Cenko and Fox (GCN 3265)." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3290 SUBJECT: GRB050416A, optical observations DATE: 05/04/18 19:25:11 GMT FROM: Adalberto Piccioni at Astronomy, Bologna U. G. Greco, C. Bartolini, A. Guarnieri, A. Piccioni (Bologna University), G.Pizzichini (IASF-CNR, sezione di Bologna), R. Poggiani (Pisa University) and I. Bruni (Osservatorio di Bologna) report: "We observed the field of GRB 050416A (Sakamoto et al., GCN 3264) using the 1.52-cm G. D. Cassini telescope of Bologna University, equipped with the BFOSC CCD imager. We obtained 2x1200s images in Rc light on 2005 April 16.345 and 16.361 UT. Due to the poor weather conditions, a seeing ~ 3", and the nearness of the Moon, we evaluate the limiting magnitude of our co-added images at ~ 19.6. We did not detect the OT given by Bradley et al. (GCN 3265). This message may be cited." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3295 SUBJECT: GRB 050416b: Tentative Swift XRT Position DATE: 05/04/20 21:18:36 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT J. A. Kennea, C. P. Hurkett, D. N. Burrows (PSU), V. Mangano (IASF/Palermo), T. Sakamoto (GSFC/NRC), N. Gehrels (NASA/GSFC) report on behalf of the Swift XRT team: The Swift BAT instrument detected a GRB at 22:35:54 UT on 16th April 2005 (GCN Circ 3279). Due to the close proximity of this burst to the moon, the observatory did not executed an automated slew at that time. This burst became visible to Swift Narrow Field Instruments at 12:48:00 UT on 20th April 2005, and was observed by Swift-XRT as a pre-planned target. From ground processed data we find a uncatalogued X-ray source within the BAT error circle, located at: RA(J2000) = 08:55:35.2, Dec(J2000) = +11:10:32. We estimate an uncertainty of about 5 arcseconds radius (90% containment). This position is 152 arcseconds from the BAT position reported in GCN 3284. This source should be considered a tentative afterglow candidate, we are currently performing further observations to determine if the source is fading. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3318 SUBJECT: GRB050416a: Radio Detection DATE: 05/04/22 19:15:34 GMT FROM: Alicia Soderberg at Caltech A. M. Soderberg (Caltech) reports on behalf of the Caltech-NRAO-Carnegie GRB Collaboration: "We observed the field centered on the XRT position of the Swift burst GRB 050416a (GCN#3268) using the VLA at a frequency of 4.86 GHz on Apr 22.04 UT (t ~ 5.6 days after the burst). We detect a radio source coincident with the optical afterglow position reported by Cenko & Fox (GCN#3265). The flux density of the source is 260 +- 55 uJy. Further observations are planned" //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3361 SUBJECT: GRB 050416b:Swift XRT afterglow upper limits DATE: 05/05/06 00:33:54 GMT FROM: David Burrows at PSU/Swift The Swift BAT instrument detected a GRB at 22:35:54 UT on 16th April 2005 (Hullinger et al., GCN 3279). Due to the close proximity of this burst to the moon, the observatory did not execute an automated slew at that time. This burst became visible to Swift Narrow Field Instruments at 12:48:00 UT on 20th April 2005 (i.e. 86.3 hours after the trigger), and was observed by Swift-XRT as a pre-planned target on 20th April, 22nd April, and 1st May 2005. Five uncataloged sources are detected within the BAT error circle(Sato et al., GCN Circ 3284), but none of them is fading. The source previously indicated as a tentative afterglow candidate in GCN 3295 (Kennea et al.) is stable within errors. Thus we cannot identify any afterglow for this GRB. We estimate 3 sigma upper limits of 2E-14, 1.7E-14, and 1.5E-14 erg/cm2/s for the flux of the GRB afterglow in the first, second and third observations, respectively. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3362 SUBJECT: GRB 050416b:Swift XRT afterglow upper limits DATE: 05/05/06 00:48:31 GMT FROM: David Burrows at PSU/Swift V. La Parola, V. Mangano (INAF-IASF/Palermo), J. A. Kennea, D. N. Burrows (PSU), T. Sakamoto (GSFC), C. P. Hurkett (U. Leicester) and N. Gehrels (GSFC) report on behalf of the Swift XRT team: The Swift BAT instrument detected a GRB at 22:35:54 UT on 16th April 2005 (Hullinger et al., GCN 3279). Due to the close proximity of this burst to the moon, the observatory did not execute an automated slew at that time. This burst became visible to Swift Narrow Field Instruments at 12:48:00 UT on 20th April 2005 (i.e. 86.3 hours after the trigger), and was observed by Swift-XRT as a pre-planned target on 20th April, 22nd April, and 1st May 2005. Five uncataloged sources are detected within the BAT error circle(Sato et al., GCN Circ 3284), but none of them is fading. The source previously indicated as a tentative afterglow candidate in GCN 3295 (Kennea et al.) is stable within errors. Thus we cannot identify any afterglow for this GRB. We estimate 3 sigma upper limits of 2E-14, 1.7E-14, and 1.5E-14 erg/cm2/s for the flux of the GRB afterglow in the first, second and third observations, respectively. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3369 SUBJECT: GRB050416A : 1 GHz limit from GMRT DATE: 05/05/06 12:25:56 GMT FROM: Resmi L at Raman Res.Inst./India C. H. Ishwara-Chandra (National Centre for Radio Astrophysics, Pune, India), A. P. Kamble and L. Resmi (Raman Research Institute, Bangalore, India) report on behalf of a larger GRB collaboration: We observed the GRB050416A field (GCN 3268) on 25th April 2005 (UT 17:30 to 22:20) with the Giant Meterwave Radio Telescope at 1280MHz. We do not detect any source within the 5" error circle of the Swift XRT. At the position of the VLA source reported by Soderberg et. al. (GCN 3318) we place a 2 sigma upper limit of 94 micro Jansky. This message may be cited. [GCN OPS NOTE; This circular was delayed 2 hrs until an account could be set up.] //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3408 SUBJECT: GRB050416: Afterglow detection at 188 nm with Swift UVOT DATE: 05/05/10 20:46:59 GMT FROM: Derek Fox at CIT Derek B. Fox (Caltech) reports on behalf of a larger collaboration: "We have created a summed image from the first 10.14 ksec of exposure on GRB050416 (BAT trigger #114753; Sakamoto et al., GCN 3264) through the "UVW2" filter of the Swift UVOT. Earlier reports have discussed the detection of the optical afterglow of this event (Cenko & Fox, GCN 3265) in the U, B, and V filters (Schady et al., GCN 3280). The UVW2 sequence consists of nine ~10-second exposures taken from 4 to 15 minutes after the burst; two ~100-second exposures taken 18 and 29 minutes after the burst, and 11 ~900-second exposures taken from 92 minutes to 2 days after the burst. The final summed frame was astrometrically registered to the USNO B-1.0 catalog. At the position of the optical afterglow we detect a source at >3-sigma confidence with a mean count rate of 6.0 +/- 0.7 cts/ksec according to the default uvotdetect analysis. Examination of individual frames suggests that the source is not distinguishable above background in the individual short (10-s and 100-s) exposures, being most prominent in the early ~900 second exposures of the sequence. The UVW2 filter bandpass is centered at 188 nm with a width of 76 nm. Since it is unlikely that significant afterglow emission would be detected blueward of the host galaxy Lyman limit at 91 nm -- with significant suppression redward to the Lyman-alpha resonance at 122 nm -- we suggest that this detection implies a redshift constraint for GRB050416 of z <~ 1.0." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3542 SUBJECT: GRB 050416(a): Host Galaxy Redshift Determination DATE: 05/06/10 00:45:36 GMT FROM: S. Bradley Cenko at Caltech S. B. Cenko, S. R. Kulkarni, A. Gal-Yam (Caltech) and E. Berger (Carnegie Observatories) report on behalf of the Caltech-NRAO-Carnegie Collaboration: We have obtained 2 x 30 minute spectra of the host galaxy of GRB 050416 (a) with the Low Resolution Imaging Spectrometer mounted on the 10-m Keck I Telescope. Observations were taken on 6 June, 2005 UT. We identify several emission lines including [OII], H-beta, H-gamma, and H- delta at a redshift of z = 0.6535 +/- 0.0002. The spectrum indicates the host galaxy is faint and blue with large amounts of ongoing star formation. We note the redshift is consistent with the prediction of Fox (3408) based on the afterglow detection in the Swift UVOT UVW2 filter. Using a fluence of 3.8e-7 erg/cm^2 (10 - 350 keV, GCN 3273), we find an isotropic gamma-ray energy release of 7.0e50 ergs. [GCN OPS NOTE; This circular was delayed 2 hrs until an account could be set up.]