This file contains both bursts: GRB 050215A and GRB 050215B. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3021 SUBJECT: GRB050215A: ROTSE-III Optical Observations DATE: 05/02/15 03:45:25 GMT FROM: Don Smith at U michigan Title: GRB050215A: ROTSE-III Optical Observations Smith, D. A., Rykoff, E. S., & Yost, S. A. (U. of Michigan) report on behalf of the ROTSE collaboration: ROTSE-IIIb, located at McDonald Observatory, Texas responded to Swift GRB050215A (Trigger #106106). An automatic response resulted in a sequence of 29 images beginning 7.2 seconds after receipt of the GCN trigger. The first image was taken at 02:16:34.2, 65.7 sec after the burst trigger. The source was fairly low on the horizon and setting. We took 10 5-s, 10 20-s and 9 60-s exposures before the alert for GRB 050215B (Trigger #106107) interrupted the sequence (See Yost et al., coming soon) The images are unfiltered and were calibrated relative to USNO A2.0. As the source is in a crowded field at relatively low galactic latitude, our limits are adversely effected by source confusion. Individual images have limiting magnitudes ranging from 15.9-17.4. Comparison to DSS (second epoch) reveals no new sources within the 3-sigma error circle to a limiting magnitude of 17.4 and 17.6 for co-adds of 10 images taken between 66 s and 18 min after the burst. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3022 SUBJECT: GRB050215B: ROTSE-III optical observations DATE: 05/02/15 04:01:32 GMT FROM: Sarah Yost at U.Michigan S.A. Yost, D.A. Smith, and E.S. Rykoff report on behalf of the ROTSE collaboration: ROTSE3B, located at McDonald Observatory, Texas, responded to GRB050215B (Swift#0106107) under fair conditions (low elevation). An automatic response (interrupting the sequence for 050215A) resulted in a sequence of 60+ images beginning 8 sec after the trigger. The first image was taken at 02:35:19.0, 97 sec after the burst. We took 10 5 sec, 10 20 sec, and 40+ 60 sec exposures. The images are unfiltered and were calibrated relative to USNO A2.0. Individual images have limiting magnitudes from 16-17.7 mag. Comparison to the DSS reveals no new sources within the 3-sigma error circle to a limiting magnitude of 17.8-18.8 for coadded sets of 10 images between 100 sec and 50 min post-burst This message may be cited //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3023 SUBJECT: GRB 050215b, BOOTES-1B optical limit DATE: 05/02/15 04:23:01 GMT FROM: Martin Jelinek at Inst.Astrophys.Andalucia,Granada Martin Jelinek, Javier Gorosabel, Alberto J. Castro-Tirado, Antonio de Ugarte Postigo, (IAA CSIC, Granada), Petr Kubanek, Rene Hudec (ASU AV CR Ondrejov) and Stanislav Vitek (FEL CVUT Praha). report: We have imaged the error box of Swift's GRB 050215b [trigger #106107], with the BOOTES-1B facility in southern Spain. Comparison with the GSC-2 catalogue does not reveal any new source. We report the following 3-sigma magnitude limits 25.6 minutes (mean obs. time) after trigger: V > 16.5 I > 15.0 on our 600s exposures. [GCN OPS NOTE (15feb05): Per author's request, the 050215c was changed to 050215b (since the HETE trigger earlier turned out to not be a real GRB.)] //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3024 SUBJECT: Swift-BAT detects two bursts: GRB050215a and GRB050215b DATE: 05/02/15 04:45:33 GMT FROM: Scott Barthelmy at NASA/GSFC S. Barthelmy, L. Barbier, J. Cummings (GSFC), E. Fenimore (LANL), N. Gehrels (GSFC), J. Greiner (MPE), D. Hinshaw (GSFC-SPSYS), D. Hullinger (GSFC/UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), T. Mitani (ISAS), K. Nakazawa (ISAS), J. Norris (GSFC), D. Palmer (LANL), A. Parsons, T. Sakamoto (GSFC) G. Sato (ISAS), M. Suzuki (Saitama), J. Tueller (GSFC), on behalf of the Swift-BAT team: The BAT instrument on Swift triggered at 02:15:28 and at 02:33:12 UT 15 Feb 05, triggers 106106 and 106107, respectively. We have done preliminary analysis on the ground using the TDRSS messages and the initial portions of the data from a telemetry downlink. For GRB050215a (Trigger 106106) the position is RA,Dec=348.382,+49.322 (J2000) with a position uncertainty of 4 arcmin (statistical plus systematic, 90% containment radius). The lightcurve is a single peak with a duration of ~6 seconds. Nearly all of the emission is in the 15-25 keV band. The Swift spacecraft automatically slewed to this burst and began follow-up observations, but that follow-up sequence was interrupted by the second burst (18 min later). For GRB050215b (Trigger 106107) the position is RA,Dec=174.450,+40.805 (J2000) with a position uncertainty of 4 arcmin (statistical plus systematic, 90% containment radius). The lightcurve is a single peak with a duration of ~10 seconds. The emission extends from 15 to ~100 keV. The Swift spacecraft also automatically slewed to this burst location and is currently doing an extended follow-up observation on this burst. We note that this burst is well suited for ground-based optical follow-up observations in the Northern hemisphere. We note that these bursts are clearly distinct and separate from each other. It is merely coincidental that these two bursts happened within a few hours after the enabling of the automatic real-time distribution of the Notices. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3025 SUBJECT: GRB050215a: No Swift UVOT Detection of Afterglow Emission DATE: 05/02/15 08:27:59 GMT FROM: Pete Roming at PSU A. Breeveld (MSSL), P. Roming (PSU), K. Mason, P. Schady (MSSL), M. Ivanushkina (PSU), T. Poole (MSSL), C. Gronwall (PSU), A. Blustin (MSSL), P. Brown (PSU), P. Schady, S. Rosen, K. McGowan, M. De Pasquale (MSSL), P. Boyd (GSFC/UMBC), S. Holland, M. Still (GSFC/USRA), W. Landsman (GSFC), S. Hunsberger (PSU), B. Hancock (MSSL), S. Koch (PSU), M. Carter, H. Huckle (MSSL), P. Broos (PSU), T. Kennedy, P. Smith (MSSL), J. Hill (PSU), C. Markwardt (GSFC/UMD), T. Sakamoto (GSFC), J. Nousek (PSU), N. Gehrels (GSFC), on behalf of the Swift UVOT team. The Swift Ultra-Violet/Optical Telescope (UVOT) began observations of GRB050215a (GCN 3024) on February 15, 2005 at 02:17:05 UT. We detect no source down to a magnitude of 19.2 in the UVW2-filter for a 9 second exposure starting 98s after the BAT trigger. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3026 SUBJECT: GRB050215b: No Swift UVOT Detection of Afterglow Emission DATE: 05/02/15 08:44:00 GMT FROM: Pete Roming at PSU P. Roming (PSU), K. Mason, P. Schady (MSSL), M. Ivanushkina (PSU), T. Poole (MSSL), C. Gronwall (PSU), A. Blustin (MSSL), P. Brown (PSU), P. Schady, S. Rosen, K. McGowan, M. De Pasquale (MSSL), P. Boyd (GSFC/UMBC), S. Holland, M. Still (GSFC/USRA), W. Landsman (GSFC), S. Hunsberger (PSU), A. Breeveld (MSSL), S. Koch (PSU), M. Carter, H. Huckle (MSSL), P. Broos (PSU), T. Kennedy, P. Smith, B. Hancock (MSSL), J. Kennea (PSU), J. Cummings (GSFC), T. Sakamoto (GSFC), J. Nousek (PSU), N. Gehrels (GSFC), on behalf of the Swift UVOT team. The Swift Ultra-Violet/Optical Telescope (UVOT) began observations of GRB050215b (GCN 3024) on February 15, 2005 at 02:35:10 UT. We detect no source down to a magnitude of 19.5 in the V-filter for a 100 second exposure 1747s after the BAT trigger. No source was detected in the other UVOT filters. The limiting magnitudes in each of the UVOT filters are as follows: UVW2 = No source identified down to 19.2 (3-sigma) for a 10 second exposure @ 88 seconds after the burst UVM2 = No source identified down to 21.3 (3-sigma) for a 100 second exposure @ 1853 seconds after the burst UVW1 = No source identified down to 20.2 (3-sigma) for a 100 second exposure @ 1959 seconds after the burst U = No source identified down to 19.8 (3-sigma) for a 100 second exposure @ 2065 seconds after the burst B = No source identified down to 19.9 (3-sigma) for a 100 second exposure @ 2171 seconds after the burst V = No source identified down to 19.5 (3-sigma) for a 100 second exposure @ 1747 seconds after the burst We caution that the instrument is not yet fully calibrated and that the magnitude limits presented here may need to be refined at a future date. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3027 SUBJECT: GRB 050215b: Swift XRT Observations DATE: 05/02/15 15:28:22 GMT FROM: David Burrows at PSU/Swift K. Page (U. Leicester), G. Tagliaferri, S. Campana, A. Moretti, C. Pagani, P. Romano, G. Chincarini (OAB), G. Cusumano, V. Mangano, V. La Parola (IASF/Palermo), D. N. Burrows, J. Kennea, J. E. Hill, J. A. Nousek (PSU), J. P. Osborne, M. Goad, A. Beardmore, A. F. Abbey, A. A. Wells (U. Leicester), P. Giommi, M. Capalbi, M. Perri, F. Tamburelli (ASDC), T. Sakamoto, L. Angelini, N. Gehrels (GSFC), W. Voges (MPE), L. Cominsky (Sonoma State U.), M. Tripicco (GSFC-SSAI), report on behalf of the Swift XRT team: The Swift BAT instrument detected GRB 050215b at 02:35:00 UT on 15 Feb 2005. The observatory executed an automated slew to the BAT position, but the XRT was in Manual State collecting calibration data and did not perform its normal automated GRB observing sequence. Furthermore, the satellite entered the SAA shortly after detecting this burst, and the XRT had data collection disabled until it exited the SAA at 03:03 to 03:10 UT, at which time the XRT was in Manual state and made observations in Windowed Timing (WT) mode. On the second orbit XRT collected data from 04:11 to 04:15 in Photon Counting (PC) mode, and from 04:44 to 04:47 in WT mode. (In between Swift was again located in the SAA). Observations continued in both WT and PC modes on subsequent orbits. With three orbits of PC mode data processed through the ground software, we find a faint, uncataloged X-ray source located 35 arcseconds from the BAT position at RA(J2000) = 11 37 46.1, Dec(J2000) = +40 47 54.3. The XRT alignment calibration is still in progress. We estimate a systematic uncertainty in this position of 6 arc seconds radius. However, the lightcurve of this source, in both WT and PC mode, does NOT appear to be fading, although the source is extremely weak and the statistics are not good enough yet for an accurate determination. GRB050215b remains the Swift Automated Target, and we expect to continue monitoring operations for the next 12 hours. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3028 SUBJECT: GRB 050215B: UKIRT K-band imaging DATE: 05/02/15 17:22:05 GMT FROM: Nial Tanvir at IofA U.Cambridge N. Tanvir, R. Priddey, M. Hughes, S. Pak, R. Chapman (U. Hertfordshire), P. O'Brien, A. Levan (U. Leicester), C. Simpson (U. Durham), T. Carroll (JACH) report on behalf of a larger collaboration: We observed the Swift/BAT position reported for GRB 050215B with the UFTI camera on UKIRT in good seeing. The exposure was in the K98 filter beginning at Feb 15.51 UT (9.76 hours post burst). We find no sources apart from the bright 2MASS star (catalogued position 11 37 46.50 +40 47 58.2) within 15 arcsec of the Swift/XRT position reported by Page et al. (GCN circular 3027), down to a limiting K-band magnitude of approx 20.5 (5 sigma). Preliminary standard star calibration gives a magnitude for the 2MASS star of K=15.4 compared to a catalogued value of 15.22. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3029 SUBJECT: GRB 050215b, BOOTES-2 simultaneous optical observations DATE: 05/02/15 18:22:51 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia M. Jelínek, A. J. Castro-Tirado, J. Gorosabel, A. de Ugarte Postigo (IAA-CSIC Granada), P. Kubanek, R. Hudec (Astronomical Institute of the Academy of Sciences, Ondrejov), T. J. Mateo Sanguino (Universidad de Huelva), T. Soria, R. Fernández (EELM-CSIC, Málaga) and J. Fabregat (Universidad de Valencia) report: The BOOTES-2 very wide field camera, located at the Estación Experimental de La Mayora (EELM-CSIC) in Málaga, observed the region of the sky containing the SWIFT/BAT error box for GRB 050215b (Barthelmy et al. GCN 3024) as part of its routine observing schedule. A 30 s exposure started at 02:33:05 UT (7 s prior to the onset of the 10 s long burst), with the following frame starting at 02:34:05 UT. Limiting (unfiltered) magnitude of 10.0 is derived for any prompt optical flash arising from this event. This message can be quoted. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3030 SUBJECT: GRB 050215b : Lulin follow-up observation DATE: 05/02/16 12:09:39 GMT FROM: Kuiyun Huang at IANCU P.S. Chiang, K.Y. Huang, W.H. Ip (NCU), Y. Urata, T. Tamagawa (RIKEN), Y. Qiu (BAO), Y.Q. Lou(THCA) on behalf of the East Asian collaboration report: We observed the SWIFT/BAT error region for GRB 050215b ( Barthelmy et al. GCN 3024) using Lulin 1-m telescope at Taiwan. We imaged a V-band 300 sec exposure at 15.65 UT (~ 13.07 hrs after the burst ) and a I-band 300 sec at 17.14 UT ( ~ 14.56 hrs after the burst ). No new source was found around X-ray source reported by Page et al. (GCN 3027) at our two observations. Compare with USNO-B1 I band stars, the limiting magnitudes are V ~ 19 and I ~ 20 (3 sigma). This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3031 SUBJECT: GRB 050215B: candidate afterglow DATE: 05/02/17 14:48:33 GMT FROM: Nial Tanvir at IofA U.Cambridge N. Tanvir, S. Pak, R. Priddey, M. Hughes (U. Hertfordshire), E. Rol, A. Levan, P. O'Brien (U. Leicester), C. Simpson (U. Durham), E. Vardoulaki (U. Oxford), T. Carroll (JACH) report on behalf of a larger collaboration: We have obtained a second epoch of UKIRT/UFTI K-band imaging of the Swift/BAT position reported for GRB 050215B. Seeing was again good (approx 0.5 arcsec compared to 0.4 arcsec on the previous night). The observation began at Feb 16.49 UT, roughly 34 hrs post burst. We find no variable sources within the XRT error circle for the object reported by Page et al (GCN circular 3027). However we find a faint, apparently variable, point source about 30 arcsec from the centre of the BAT error circle. It has magnitude K=20.23+-0.11 on night 1 and K=20.75+-0.22 on night 2 (both measured in a 0.9 arcsec aperture), which we believe is therefore a good candidate for the afterglow of this burst. Although near the detection limit, the source on the second night may be slightly extended (possibly also on the first), which would indicate a host contribution, and hence that particularly the second magnitude should be treated as an upper limit on the afterglow magnitude. The location of this object, is 15.7 arcsec E and 12.7 arcsec S of the 2MASS/USNO-B1 catalogued object (whose magnitude we refine to K=15.46 based on our standard star calibration). ie. in the USNO-B1 system the candidate afterglow is located at: 11:37:47.90 40:47:45.6 Postage stamp images are available on: http://star-www.herts.ac.uk/~nrt/050215b.html Further followup is ongoing. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3032 SUBJECT: GRB 050215b: Swift XRT Source Variability DATE: 05/02/17 21:39:55 GMT FROM: David Burrows at PSU/Swift M. Goad, K. Page, J. P. Osborne, P. O'Brien (U. Leicester), D. C. Morris, J. A. Kennea, D. N. Burrows, J. L. Racusin, J. E. Hill, M. M. Chester, J. A. Nousek (PSU), P. Giommi, M. Capalbi, M. Perri, F. Tamburelli (ASDC), P. Romano, G. Tagliaferri, S. Campana, A. Moretti, C. Pagani, G. Chincarini (INAF-OAB), G. Cusumano, V. Mangano, V. La Parola (INAF-IASF/Palermo), A. A. Wells (U. Leicester), B. Zhang (U. Nevada), T. Sakamoto, L. Angelini, N. Gehrels (GSFC), W. Voges (MPE), L. Cominsky (Sonoma State U.), M. Tripicco (GSFC-SSAI) report on behalf of the Swift XRT team: The Swift XRT has continued to monitor the X-ray source (designated SWIFT J113746.1+404754) discussed in GCN 3027 (Page et al. 2005) in the field of GRB 050215b. We now have data over two epochs, indicating a decaying light curve for this object. First epoch: We obtained 5155 seconds of data in Photon-Counting mode (our most sensitive observing mode) from six orbits beginning at 04:09:52 UT on 2005-02-15. The average count rate for SWIFT J113746.1+404754 in the first two orbits is 0.0231 +/- 0.0050 cps (0.2-10 keV). The average count rate for this source over orbits 3-6 is 0.0108 +/- 0.0018 cps, consistent with a decreasing rate. Second epoch: We obtained 1640 seconds on SWIFT J113746.1+404754 between 01:36:37 UT and 09:39:42 UT on 2005-02-17 in Photon-Counting mode. The source is undetectable in this second epoch, with a 95% confidence upper limit on the count rate of 0.0018 cps (0.2-10 keV, calculated using the method of Kraft, Burrows, and Nousek 1993, ApJ, 1991, 374, 344). The fading count rate suggests that this source could be the X-ray afterglow of GRB 050215b, although it is extremely weak in the first epoch (a few times 10^-13 ergs/cm**2/s at about 95 minutes post-burst). However, we cannot rule out other possibilities. We note that there is an optical source (R=17.3, B=18.5) in the USNO catalog at the edge of the XRT error circle of the detected X-ray source reported in GCN 3027. If we assume that this object is the optical counterpart of our X-ray source, the optical-to-X-ray ratio is alpha_ox~1.35 during our first epoch, compatible with a radio-quiet AGN. Optical spectroscopy of this USNO object would help determine its nature, and could eliminate it from consideration as a possible counterpart of SWIFT J113746.1+404754. We do not detect any X-ray object in either epoch at the position of the UKIRT afterglow candidate (Tanvir et al. 2005, GCN 3031). We place 95% upper limits on the XRT count rate from the UKIRT afterglow candidate of 0.0006 cps in the first epoch and 0.0018 cps in the second epoch (0.2-10 keV), within a 20 arcsecond radius circle of the UKIRT position. Further Swift observations of this field are planned through the weekend. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3033 SUBJECT: GRB050215b: P60 Optical Observations DATE: 05/02/18 00:51:27 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 field of the Swift GRB050215b with the automated Palomar 60-inch telescope. Our first epoch consists of 9 x 120 s exposures in the Kron R band, taken at a mean time of 12:00 February 15 UT (~ 9.5 hours after the burst). Our second epoch consists of 5 x 120 s exposures in the Kron R band, taken at a mean time of 6:50 February 17 UT (~ 52.3 hours after the burst). Both epochs reach a 3-sigma limiting magnitude of R ~ 20.5. The only source present in either epoch in the XRT error circle (Page et. al., GCN 3027) is the USNO source discussed by Goad et. al. (GCN 3032). We find no evidence for any variability in this source (R = 17.23 +/- 0.1 in epoch 1, R = 17.30 +/- 0.1 in epoch 2). To our limits, we find no optical counterpart to the NIR candidate proposed by Tanvir et. al. (GCN 3031) in either epoch. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3034 SUBJECT: GRB 050215b: XRT confirmation of IR afterglow candidate DATE: 05/02/18 18:35:51 GMT FROM: David Burrows at PSU/Swift M. Goad, K. Page, J. P. Osborne, P. O'Brien (U. Leicester), D. C. Morris, J. A. Kennea, D. N. Burrows, J. L. Racusin, J. E. Hill, M. M. Chester, J. A. Nousek (PSU), P. Giommi, M. Capalbi, M. Perri, F. Tamburelli (ASDC), P. Romano, G. Tagliaferri, S. Campana, A. Moretti, C. Pagani, G. Chincarini (INAF-OAB), G. Cusumano, V. Mangano, V. La Parola (INAF-IASF/Palermo), A. A. Wells (U. Leicester), B. Zhang (U. Nevada), T. Sakamoto, L. Angelini, N. Gehrels (GSFC), W. Voges (MPE), L. Cominsky (Sonoma State U.), M. Tripicco (GSFC-SSAI) report on behalf of the Swift XRT team: We confirm that the fading IR object discovered by Tanvir et al. 2005 (GCN 3031) is the afterglow of GRB 050215b. We have discovered an error in the astrometry for previously-reported XRT positions on the field of GRB050215b. This affects both the position reported by Page et al. 2005 (GCN 3027) and some of the information in Goad et al. 2005 (GCN 3032). We recommend that those GCNs not be referenced, and that this Circular be referenced instead for XRT observations of this burst. The corrected XRT position for the afterglow of GRB 050215b is RA(J2000) = 11 37 47.7 , Dec(J2000) = +40 47 44.0 The estimated uncertainty in this position is 6 arcseconds radius. We note that this corrected error circle now includes the UKIRT counterpart candidate (Tanvir et al. 2005, GCN 3031). Further, the new XRT position puts the USNO/2MASS object mentioned in GCN 3032 outside of the XRT error circle. We can therefore definitely confirm this object as the afterglow of GRB 050215b. We can also now definitely say that the XRT counterpart is fading, but with a fairly flat decay curve (slope of -0.76 +/- 0.26). The Swift XRT has continued to monitor the X-ray source (now designated SWIFT J113747.7+404744) discussed in GCN 3027 (Page et al. 2005) in the field of GRB 050215b. We now have data over two epochs, indicating a decaying light curve for this object. First epoch: We obtained 5155 seconds of data in Photon-Counting mode (our most sensitive observing mode) from six orbits beginning at 04:09:52 UT on 2005-02-15. The average count rate for SWIFT J113747.7+404744 in the first two orbits is 0.0231 +/- 0.0050 cps (0.2-10 keV). The average count rate for this source over orbits 3-6 is 0.0108 +/- 0.0018 cps, consistent with a decreasing rate. Second epoch: We obtained 1640 seconds on SWIFT J113747.7+404744 between 01:36:37 UT and 09:39:42 UT on 2005-02-17 in Photon-Counting mode. The source is undetectable in this second epoch, with a 95% confidence upper limit on the count rate of 0.0018 cps (0.2-10 keV, calculated using the method of Kraft, Burrows, and Nousek 1993, ApJ, 1991, 374, 344). Further Swift observations of this field are planned through the weekend. [GCN OPS NOTE (18feb05): Per author's request some typos were corrected: In lines 42 and 55, "J1137477+404744" was changed to "J113747.7+404744". In line 49 "J113746.1+404754" was changed to "J113747.7+404744".] //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3035 SUBJECT: GRB 050215B: Radio Observations DATE: 05/02/19 01:26:42 GMT FROM: Alicia Soderberg at Caltech A. M. Soderberg (Caltech) and D. A. Frail (NRAO) report on behalf of a larger collaboration: "On 2005 Feb 18.5 UT we carried out follow-up observations with the VLA at 8.46 GHz centered on the optical afterglow candidate (GCN 3031) of GRB 050215B (GCN 3024). Within the XRT position circle of 6-arcsec radius (GCN 3034) there are no radio sources to a 3-sigma limit of 93 microJy." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3037 SUBJECT: GRB050215b: Swift UVOT Detection of Afterglow Emission DATE: 05/02/19 15:19:47 GMT FROM: Pete Roming at PSU K. Mason, P. Schady (MSSL), M. Ivanushkina (PSU), T. Poole (MSSL), C. Gronwall (PSU), A. Blustin (MSSL), P. Brown (PSU), S. Rosen, K. McGowan, M. De Pasquale (MSSL), P. Boyd (GSFC/UMBC), S. T. Holland, M. Still (GSFC/USRA), W. Landsman (GSFC), S. Hunsberger (PSU), A. Breeveld (MSSL), P. Roming (PSU), M. Carter, H. Huckle (MSSL), P. Broos (PSU), T. Kennedy, P. Smith, B. Hancock (MSSL), S. Koch, D. Morris (PSU), S. Barthelmy, T. Sakamoto (GSFC), J. Nousek (PSU), N. Gehrels (GSFC), on behalf of the Swift UVOT team. After further observations of GRB 050215B with the Swift Ultra-Violet/Optical Telescope (UVOT), we have identified a source near the position identified by Tanvir, et al (GCN 3031). The source was detected at a position of RA = 11:37:48.03 and Dec = +40:47:43.4 (J2000). The UVOT alignment is not yet fully calibrated, therefore, we estimate a systematic uncertainty of about +/- 1arcsecond in this position. Reexamination of the early time UVOT observations at this location are consistent with our previously reported findings of no detected afterglow (Roming et al, GCN 3026). The source was identified at a magnitude of 21.7 by co-adding three V-band images which were taken 2.2-9.7 hours after the initial trigger. Examination of V-band images taken after this time reveal no reliable detections. We caution that the instrument is not yet fully calibrated and that the magnitudes presented here may need to be refined. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3051 SUBJECT: GRB050215b: Faulkes North and SDSS limits on UKIRT candidate DATE: 05/02/20 21:06:15 GMT FROM: Alessandro Monfardini at JMU/Liverpool Robotic Tele A. Monfardini (Liverpool), N. Tanvir (Hertfordshire), C. Mundell (Liverpool), R. Smith (Liverpool), A. Levan (Leicester), E. Rol (Leicester), P. O'Brien (Leicester) and M. Bode (Liverpool) on behalf of the ROBONET collaboration report: "We observed the field of GRB050215b (GCN 3024) with the 2.0m Faulkes North Telescope on Haleakala. We obtained SDSS-I imaging commencing 1.229 days after the burst under poor seeing conditions. A re-analysis at the position of the candidate first reported by Tanvir et. al and then confirmed by XRT (GCN 3031, GCN 3034) shows no detection on our images up to I=20.5 (limited by technical problems). We reiterate the coordinates: RA=11:37:47.90 DEC=+40:47:45.6 We also searched for possible hosts in SDSS plates (observations date: 2003-04-01) and found no candidates within 5 arcsec up to (SDSS filters): u = 21.0 g = 21.9 r = 22.0 (R ~ 21.9) i = 21.7 (I ~ 21.3) z = 20.2 These values were derived using SDSS field photometry references." This message can be cited //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3053 SUBJECT: HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash DATE: 05/02/23 05:01:42 GMT FROM: Don Lamb at U.Chicago HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash Y. Nakagawa, G. Ricker, J-L. Atteia, N. Kawai, D. Lamb, and S. Woosley, on behalf of the HETE Science Team; T. Donaghy, E. Fenimore, M. Galassi, C. Graziani, M. Matsuoka, T. Sakamoto, R. Sato, Y. Shirasaki, M. Suzuki, T. Tamagawa, Y. Urata, T. Yamazaki, Y. Yamamoto, and A. Yoshida, on behalf of the HETE WXM Team; N. Butler, G. Crew, J. Doty, G. Prigozhin, R. Vanderspek, J. Villasenor, J. G. Jernigan, A. Levine, G. Azzibrouck, J. Braga, R. Manchanda, and G. Pizzichini, on behalf of the HETE Operations and HETE Optical-SXC Teams; M. Boer, J-F Olive, J-P Dezalay, and K. Hurley, on behalf of the HETE FREGATE Team; report: GRB 050215b (=U11570) occurred 36 degrees off the HETE boresight, and therefore well within the FREGATE field of view but only at the very edge of the WXM field of view. Consequently, the burst is seen in the FREGATE data but not in the WXM data. Using a simple power-law model to fit the FREGATE spectral data, we find a best-fit power-law index of beta = -2.2 (+0.4/-0.6). Using a constrained Band model (Sakamoto et al., ApJ, 602, 875, 2004) to fit the data, we find a best-fit value for the peak energy of E_peak = 17.6 keV; a 68% confidence region 4.8 keV < E_peak < 23.7 keV, a 95% upper bound E_peak < 30.3 keV, and a 99% upper bound E_peak < 35.7 keV. Finally, using a Band model with the low-energy power-law index alpha fixed at -1 to fit the data, we find fluences of S_x (2-30 keV) = 2.8 (+3.3/-1.1) x 10-7 erg cm-2 and S_gamma (30-400 keV) = 1.7 (+2.5/-1.3) x 10-7 erg cm-2. The best-fit value of S_x/S_gamma is therefore 1.65. Taken together, these results are strong evidence that GRB 050215b was an X-Ray Flash. We note that a supernova component has not been definitively established in the afterglow of any X-Ray Flash and that any supernova component in the afterglow of GRB 050215b would be expected to peak soon. We therefore encourage further observations of the afterglow of this burst. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3062 SUBJECT: Confirmed XRF nature for GRB050215b DATE: 05/02/24 00:22:10 GMT FROM: Takanori Sakamoto at NASA/GSFC T. Sakamoto, S. Barthelmy, N. Gehrels, J. Cummings, A. Parsons, J. Tueller (GSFC), E. Fenimore, D. Palmer (LANL), D. Hullinger, C. Markwardt (GSFC/UMD), H. Krimm (GSFC/USRA), G. Sato (ISAS), M. Suzuki (Saitama) With the further analysis of the BAT spectral data of GRB050215b, we confirmed the nature of X-ray flash for GRB050215b. If we used the best fit Epeak energy of 17.6 keV derived from the HETE data (Nakagawa et al, Circ 3053), the transition energy between the lower energy cutoff power-law component and the higher energy power-law component of the Band function (Band et al. 1993) will be 26.4 keV if we assume alpha=-1 and beta=-2.5. Based on this estimation, we tried to fit the BAT spectrum only using above 30 keV to see the evidence of the power-law slope of steeper than -2. With this fit, we obtained the best fit power-law index of -2.99 (-1.02/+0.77; 90% confidence). The significance in the power-law index of steeper than -2.0 is 97%. This is a strong indication that BAT observed the higher portion of the Band function, and the Epeak of GRB050215b is indeed below 30 keV. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3066 SUBJECT: XRF/GRB 050215B: Radio Observations DATE: 05/02/28 20:57:19 GMT FROM: Alicia Soderberg at Caltech A. M. Soderberg (Caltech) and D. A. Frail (NRAO) report on behalf of a larger collaboration: "On 2005 Feb. 27.09 UT we carried out follow-up observations with the VLA at 8.46 GHz centered on the afterglow (GCN 3031,3034) of XRF/GRB 050215B (GCN 3024,3053). Within a circle of 1-arcsec radius there are no radio sources to a 3-sigma limit of 156 microJy. No further observations are planned." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3069 SUBJECT: GRB050215B: Late-Time Swift UVOT Observations DATE: 05/03/03 20:17:31 GMT FROM: Pete Roming at PSU P. Brown (PSU), S. Rosen, K. McGowan, M. De Pasquale (MSSL), P. Boyd (GSFC/UMBC), S. T. Holland, M. Still (GSFC/USRA), W. Landsman (GSFC), S. Hunsberger (PSU), A. Breeveld (MSSL), P. Roming (PSU), K. Mason, P. Schady (MSSL), M. Ivanushkina (PSU), T. Poole (MSSL), C. Gronwall (PSU), A. Blustin (MSSL), S. Koch (PSU), M. Carter, H. Huckle (MSSL), P. Broos (PSU), T. Kennedy, P. Smith, B. Hancock (MSSL), M. Chester (PSU), B. Zhang (UNLV), J. Nousek (PSU), N. Gehrels (GSFC), on behalf of the Swift UVOT team. The Swift Ultra-Violet/Optical Telescope (UVOT) observed the field of the X-ray flash GRB050215B (GCN 3024) between February 25, 2005 and February 28, 2005 UT. The 5-sigma limiting magnitudes for each exposure are presented below. We stress that the limiting magnitudes are based on ground calibrations and are uncertain by approximately +/-0.5 mag. # Exposure # Date (UTC) Time Time (s) Filter Mag 2005-02-25 15:13:13 1670.52 V 22.2 2005-02-25 19:52:34 2189.47 B 23.0 2005-02-25 21:32:35 2068.95 U 22.7 2005-02-25 23:27:38 985.24 V 21.9 2005-02-26 02:34:31 1351.94 V 22.0 2005-02-27 15:20:04 2099.11 B 22.9 2005-02-28 01:07:03 1620.44 V 22.2 2005-02-28 10:40:04 1919.99 B 22.9 We find no evidence for a brightening source, such as a supernova component, at the location of the afterglow seen by UKIRT (GCN 3031).