This file contains both bursts: GRB 050219A and GRB 050219B //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3036 SUBJECT: GRB 050219: Prompt X-ray position DATE: 05/02/19 13:35:10 GMT FROM: David Burrows at PSU/Swift P. Romano (INAF-OAB), M. Perri (ASDC), A. Beardmore (U. Leicester), V. Mangano (INF-IASF/Palermo), D. N. Burrows, J. E. Hill, (PSU), B. Zhang (U. Nevada), and N. Gehrels (GSFC) report on behalf of the Swift XRT team: The Swift BAT instrument detected a GRB at 12:40:01 UT on 19 February 2005. The observatory executed an automated slew to the BAT position and the XRT began taking data at 12:41:33.38 UT. The XRT was in Auto state and reports a prompt position of: GRB-RA= 166.41396, GRB-DEC= -40.68277 RA(J2000) = 11h 05m 39.4s DEC(J2000) = -40:40:58.0 We estimate an uncertainty of about 6 arcseconds. We have not examined the XRT image yet due to technical problems, but at first glance, this appears to be a valid position. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3038 SUBJECT: GRB 050219: Swift-BAT detection of a burst DATE: 05/02/19 18:23:22 GMT FROM: Scott Barthelmy at NASA/GSFC D. Hullinger (GSFC/UMD), S. Barthelmy, L. Barbier, J. Cummings (GSFC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), J. Norris (GSFC), J. Nousek (PSU), D. Palmer (LANL), A. Parsons (GSFC), M. Perri (ASDC), T. Sakamoto (GSFC), G. Sato (ISAS), A. Smale (NASA HQ), M. Suzuki (Saitama), J. Tueller (GSFC), B. Zhang (UNLV) on behalf of the Swift-BAT team: At 12:40:01 UT, the Swift Burst Alert Telescope (BAT) triggered and located on-board GRB050219. The spacecraft autonomously slewed to the burst location (started at T+12 sec and was on target at T+78 sec). The XRT and UVOT instruments then began their standard set of pre-programmed observing sequences. Using the time interval of the burst before the slew, the ground-calculated location is RA,Dec 166.409,-40.677 (J2000) with an uncertainty of 4 arcmin (radius, including a systematic uncertainty, 90% containment). The burst was 43 degrees off the BAT boresight (30% encoding). It is within 25 arcsec of the XRT position (Romano et al., GCN Circ 3036). The burst lightcurve has two overlapping peaks, with a T90 duration of ~23 sec. The peak flux is 5.5 ph/cm2/sec for a 1-sec interval (15-350 keV). The fluence is ~9.4e-6 erg/cm^2 (15-350 keV). //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3039 SUBJECT: GRB050219a: No Swift UVOT Detection of Afterglow Emission DATE: 05/02/19 22:46:56 GMT FROM: Pete Roming at PSU 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. Holland, M. Still (GSFC/USRA), W. Landsman (GSFC), S. Hunsberger (PSU), A. Breeveld (MSSL), P. Roming (PSU), K. Mason, H. Huckle (MSSL), P. Broos (PSU), T. Kennedy, P. Smith, B. Hancock (MSSL), S. Koch (PSU), M. Carter (MSSL), J. Racusin (PSU), E. Fenimore (LANL), B. Zhang (UNLV), J. Nousek (PSU), N. Gehrels (GSFC), on behalf of the Swift UVOT team. The Swift Ultra-Violet/Optical Telescope (UVOT) began observations of GRB050219a on February 19, 2005, at 12:41:21 UT, 80 seconds after the initial Swift BAT trigger (Hullinger et al, GCN 3038). We detect no source at the Swift XRT position (Romano et al, GCN 3036). The limiting magnitudes in each of the UVOT filters are as follows: UVW2 ~ 21.0 (3-sigma) for a combined 277 second exposure starting @ 80 seconds after the burst UVM2 ~ 20.8 (3-sigma) for a combined 277 second exposure starting @ 201 seconds after the burst UVW1 ~ 21.7 (3-sigma) for a combined 287 second exposure starting @ 216 seconds after the burst U ~ 21.6 (3-sigma) for a combined 280 second exposure starting @ 230 seconds after the burst B ~ 21.5 (3-sigma) for a combined 278 second exposure starting @ 245 seconds after the burst V ~ 20.7 (3-sigma) for a combined 374 second exposure starting @ 96 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. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3040 SUBJECT: GRB 050219a: Refined XRT position DATE: 05/02/19 23:29:58 GMT FROM: David Burrows at PSU/Swift K. L. Page, M. R. Goad, O. Godet, J. P. Osborne, (U. Leicester), M. Perri (ASDC), J. L. Racusin, D. N. Burrows, (PSU), C. Pagani, G. Tagliaferri (INAF-OAB), V. Mangano (INAF-IASF/Palermo), K. Hurley (UC-Berkeley), N. White, N. Gehrels (GSFC), B. Zhang (U. Nevada), report on behalf of the Swift XRT team: We report a refined XRT position for GRB 050219a (Romano et al. 2005, GCN 3036; Hullinger et al. 2005, GCN 3038), based on ground-processing of XRT Photon-Counting mode data taken during the first orbit after the burst. The refined position is: RA(J2000) = 11:05:38.8, Dec(J2000) = -40:40:58.3. We estimate an uncertainty of about 6.3 arcseconds. The lightcurve of this burst is fading, with a steep power-law up to about 200 s post-burst and a shallower power law at later times. Swift observations of this burst ended at 21:05:36.00 UT, when the Swift BAT triggered on GRB 050219b, which replaced GRB 050219a as the new GRB target in the on-board schedule. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3041 SUBJECT: GRB 050219a, optical observations DATE: 05/02/19 23:50:51 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia A. de Ugarte Postigo (IAA-CSIC, Granada), S. Eguchi (Stelab, Nagoya Univ.), J. Gorosabel (IAA-CSIC), Ph. Yock (Univ. of Auckland) and A.J. Castro-Tirado (IAA-CSIC), report: "Following the detection by SWIFT of GRB 050219a (Hullinger et al. GCN Circ. 3038) we imaged the error box with the 0.6 m telescope at Mt. John Univ. Observatory. We obtained 3 x 300s images with the MOA camera (+ wide R-band filter) under poor seeing conditions (4"- 5") starting on 19.613 Feb (i.e. 2.05 hr after the event). Additional observations were performed with a wide B-band filter. Comparison of the stacked R-band image with the DSS-2 revealed neither counterpart within the 6" radius X-ray afterglow position given by the SWIFT/XRT (Romano et al. GCN Circ. 3036) nor variable source to about R = 20.5 within the 4' radius SWIFT/BAT error box." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3042 SUBJECT: GRB 050219b: Swift XRT Position DATE: 05/02/20 00:29:56 GMT FROM: David Burrows at PSU/Swift D. N. Burrows, J. E. Hill, J. A. Kennea, J. L. Racusin (PSU), C. Pagani, A. Moretti (INAF-OAB), O. Godet, A. F. Abbey (U. Leicester), V. La Parola (INAF-IASF/Palermo), F. Tamburelli (ASDC), K. Hurley (UC-Berkeley), B. Zhang (U. Nevada), D. Hinshaw, L. Angelini, N. White, N. Gehrels (GSFC), report on behalf of the Swift XRT team: The Swift BAT instrument detected GRB 050219b at 21:05:51 UT on 19 February 2005. The burst was too close to the Earth limb to allow immediate observation by the XRT and UVOT. The observatory executed an automated slew to the BAT position at 21:56:25 UT and the XRT began taking data at about 21:58 UT. The XRT was in Auto state and attempted to obtain a GRB position, but the source was too faint to obtain a reliable on-board centroid. The ground-processed centroid of this image gives an approximate source position of: RA(J2000) = 05:24:26.5 Dec(J2000) = -57:47:51.3 We estimate an uncertainty of 15 arcseconds in this position. XRT then began observations in Windowed Timing mode, which provides 1-D position information. There appears to be a fairly bright X-ray source at a position bounded by the following error box: RA, Dec (J2000): Corner #1: 05:25:44.9, -57:55:55.3 Corner #2: 05:25:44.2, -57:55:57.4 Corner #3: 05:24:41.7, -57:33:54.5 Corner #4: 05:24:41.0, -57:33:56.6 Photon-counting mode frames taken in the following orbit are expected to produce a more accurate position, and will be reported when they become available on the ground. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3043 SUBJECT: GRB 050219b: CORRECTION: Swift XRT Position DATE: 05/02/20 00:46:10 GMT FROM: David Burrows at PSU/Swift D. N. Burrows, J. E. Hill, J. A. Kennea, J. L. Racusin (PSU), C. Pagani, A. Moretti (INAF-OAB), O. Godet, A. F. Abbey (U. Leicester), V. La Parola (INAF-IASF/Palermo), F. Tamburelli (ASDC), K. Hurley (UC-Berkeley), B. Zhang (U. Nevada), D. Hinshaw, L. Angelini, N. White, N. Gehrels (GSFC), report on behalf of the Swift XRT team: CORRECTION: shortly after submitting this information to the GCN, we discovered an error in the XRT position. The original rectangular error box based on WT mode data was correct, but the error circle based on image mode data was incorrect. That position is corrected below. The Swift BAT instrument detected GRB 050219b at 21:05:51 UT on 19 February 2005. The burst was too close to the Earth limb to allow immediate observation by the XRT and UVOT. The observatory executed an automated slew to the BAT position at 21:56:25 UT and the XRT began taking data at about 21:58 UT. The XRT was in Auto state and attempted to obtain a GRB position, but the source was too faint to obtain a reliable on-board centroid. The ground-processed centroid of this image gives an approximate source position of: CORRECTION: RA(J2000) = 05:25:15.2 Dec(J2000) = -57:45:25.2 We estimate an uncertainty of 15 arcseconds in this position. XRT then began observations in Windowed Timing mode, which provides 1-D position information. There appears to be a fairly bright X-ray source at a position bounded by the following error box: RA, Dec (J2000): Corner #1: 05:25:44.9, -57:55:55.3 Corner #2: 05:25:44.2, -57:55:57.4 Corner #3: 05:24:41.7, -57:33:54.5 Corner #4: 05:24:41.0, -57:33:56.6 Photon-counting mode frames taken in the following orbit are expected to produce a more accurate position, and will be reported when they become available on the ground. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3044 SUBJECT: GRB 050219b: Swift-BAT detection of a burst DATE: 05/02/20 01:03:47 GMT FROM: Scott Barthelmy at NASA/GSFC J. Cummings, S. Barthelmy, L. Barbier, J. Cannizzo (GSFC), M. Chester (PSU), E. Fenimore, M. Galassi (LANL), N. Gehrels (GSFC), D. Hullinger (GSFC/UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC), G. Sato (ISAS), M. Suzuki (Saitama), T. Takahashi (ISAS), J. Tueller (GSFC), B. Zhang (UNLV) on behalf of the Swift-BAT team: At 21:05:51 UT, the Swift Burst Alert Telescope (BAT) triggered and located on-board GRB050219b. Because of the Earth-limb constraint, the spacecraft could not immediately slew to the burst location. The location became unconstrained at T+50 min, and the spacecraft slewed. The XRT and UVOT instruments then began their standard set of pre-programmed observing sequences. Using the time interval of the burst, the ground-calculated location is RA,Dec 81.287,-57.770 (J2000) with an uncertainty of 4 arcmin (radius, including a systematic uncertainty, 90% containment). The burst was 54 degrees off the BAT boresight (10% encoding). The burst lightcurve has five overlapping peaks preceeded by a slow rise, with a T90 duration of ~27 sec (and T50 is 6.8 sec). The peak flux is 26 ph/cm2/sec for a 1-sec interval (15-350 keV). Using a simple power law model, the fluence is ~2.3 (+/-30%) e-5 erg/cm^2 (15-350 keV). //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3045 SUBJECT: GRB 050219b: Refined XRT position DATE: 05/02/20 03:09:51 GMT FROM: David Burrows at PSU/Swift J. L. Racusin (PSU), C. Pagani, S. Campana (INAF-OAB), V. La Parola (INAF-IASF/Palermo), D. C. Morris, D. N. Burrows, J. A. Nousek (PSU), O. Godet, A. F. Abbey (U. Leicester), F. Tamburelli (ASDC), K. Hurley (UC-Berkeley), B. Zhang (U. Nevada), D. Hinshaw, L. Angelini, N. White, N. Gehrels (GSFC), report on behalf of the Swift XRT team: Ground processing of Photon Counting mode data from 3 epochs (roughly 3600 - 10,000 s post-burst) gives the following refined Swift XRT afterglow position for GRB 050219b: RA(J2000) = 05:25:15.3 Dec(J2000) = -57:45:09.2 The estimated uncertainty in this position is 6.3 arcseconds. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3046 SUBJECT: GRB050219b: No Swift UVOT Detection of Afterglow Emission DATE: 05/02/20 04:45:45 GMT FROM: Patricia Schady at MSSL/Swift 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. Holland, M. Still (GSFC/USRA), W. Landsman (GSFC), S. Hunsberger (PSU), A. Breeveld (MSSL), P. Roming (PSU), K. Mason, P. Schady (MSSL) P. Broos (PSU), T. Kennedy, P. Smith, B. Hancock (MSSL), S. Koch (PSU), M. Carter, H. Huckle (MSSL), J. Racusin (PSU), E. Fenimore (LANL), B. Zhang (UNLV), J. Nousek (PSU), N. Gehrels (GSFC), on behalf of the Swift UVOT team. The Swift Ultra-Violet/Optical Telescope (UVOT) began observations of GRB050219b on February 19, 2005, at 12:57:51 UT, 52 minutes after the initial Swift BAT trigger (Cummings et al, GCN 3044). The delay in observations was due to the Earth-limb constraint, which prevented an immediate slew. We detect no source at the Swift XRT position (Burrows et al, GCN 3043). The limiting magnitudes (3-sigma) in each of the UVOT filters are as follows: Filter Lim_Mag Duration T_start UVW2 ~ 22.04 1154 T+3120 UVM2 ~ 20.95 100 T+3243 UVW1 ~ 20.65 100 T+3349 U ~ 20.92 100 T+3455 B ~ 20.85 100 T+3561 V ~ 19.38 100 T+3136 The limiting magnitude for the UVW2 filter was calculated from a summation of four separate exposures taken at different times between observations made in other filters. This is the cause of the overlap between the duration of the UVW2 exposure and the start of some of the other exposures. We caution that the instrument is not yet fully calibrated and that the magnitude limits presented here may need to be refined. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3047 SUBJECT: GRB 050219b: Optical and near-IR observations from LCO DATE: 05/02/20 06:03:42 GMT FROM: Edo Berger at Carnegie Obs E. Berger, D. Kelson (Carnegie Observatories) and S. Gonzalez (Las Campanas Observatory) report: "We imaged a field centered on the XRT error circle (GCN 3045) of GRB 050219b (GCN 3044) with the Las Campanas Observatory's du Pont 2.5-m telescope in the Ks-band and the Swope 40-in telescope in the R-band (2005, Feb 20.095, 5.2 hours after the burst). We do not detect any bright sources within the 6.3 arcsec radius XRT error circle in either band. However, a faint source close to the detection limit of the Ks-band image is located at (J2000): RA = 05:25:15.21 DEC = -57:45:10.4 about 1.3" from the nominal XRT position." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3048 SUBJECT: GRB 050219a: Optical observations from LCO DATE: 05/02/20 08:02:54 GMT FROM: Edo Berger at Carnegie Obs E. Berger (Carnegie Observatories) and S. Gonzalez (Las Campanas Observatory) report: "We imaged a field centered on the XRT error circle (GCN 3040) of GRB 050219a (GCN 3038) with the Las Campanas Observatory's Swope 40-in telescope in the I-band for a total of 20 min (2005, Feb 20.264, 17.7 hours after the burst). We do not detect any sources within the 6.3 arcsec radius XRT error circle to a limit of about 21.5 mag." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3049 SUBJECT: GRB 050219b: CORRECTION to refined XRT position DATE: 05/02/20 14:46:53 GMT FROM: David Burrows at PSU/Swift J. L. Racusin (PSU), C. Pagani, S. Campana (INAF-OAB), V. La Parola (INAF-IASF/Palermo), D. C. Morris, D. N. Burrows, J. A. Nousek (PSU), O. Godet, A. F. Abbey (U. Leicester), F. Tamburelli (ASDC), K. Hurley (UC-Berkeley), B. Zhang (U. Nevada), D. Hinshaw, L. Angelini, N. White, N. Gehrels (GSFC), report on behalf of the Swift XRT team: We have found an error in the processing that produced the refined Swift XRT position reported in GCN 3045. We have now corrected that error and have a new, corrected position for the X-ray afterglow of GRB 050219b: CORRECTED COORDINATES: RA(J2000) = 05:25:16.31 Dec(J2000) = -57:45:27.31 The estimated uncertainty in this position is 6.3 arcseconds. Please refer to this GCN instead of GCN 3045. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3050 SUBJECT: GRB050219b: No Swift UVOT Detection of Afterglow Emission DATE: 05/02/20 19:06:55 GMT FROM: Patricia Schady at MSSL/Swift 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. 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. Kennedy, P. Smith, B. Hancock (MSSL), S. Koch (PSU), M. Carter, H. Huckle (MSSL), P. Broos, J. Racusin (PSU), E. Fenimore (LANL), B. Zhang (UNLV), J. Nousek (PSU), N. Gehrels (GSFC), on behalf of the Swift UVOT team. The Swift Ultra-Violet/Optical Telescope (UVOT) began observations of GRB050219b on February 19, 2005, at 12:57:51 UT, 52 minutes after the initial Swift BAT trigger (Cummings et al, GCN 3044). The delay in observations was due to the Earth-limb constraint, which prevented an immediate slew. We detect no source at the Swift XRT position (Burrows et al, GCN 3043). The limiting magnitudes (3-sigma) in each of the UVOT filters are as follows: A re-examination of the UVOT data at the new XRT position (Racusin et al, GCN 3049) revealed no new source detection down to the following 3-sigma limiting magnitudes Filter Lim_Mag Duration T_start UVW2 ~ 22.16 1154 T+3120 UVM2 ~ 22.24 1435 T+3243 UVW1 ~ 22.23 940 T+3349 U ~ 20.74 100 T+3455 B ~ 20.9 100 T+3561 V ~ 19.41 100 T+3136 Several exposures were taken in the UV filters, and these were co-added in order to derive the limiting magnitudes. This is the cause of the apparent overlap between the duration of these exposure and the start time of the exposures in the optical filters. We caution that the instrument is not yet fully calibrated and that the magnitude limits presented here may need to be refined. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3052 SUBJECT: GRB050219b: CORRECTION to time of UVOT observations DATE: 05/02/21 20:34:24 GMT FROM: Patricia Schady at MSSL/Swift 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. 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. Kennedy, P. Smith, B. Hancock (MSSL), S. Koch (PSU), M. Carter, H. Huckle (MSSL), P. Broos, J. Racusin (PSU), E. Fenimore (LANL), B. Zhang (UNLV), J. Nousek (PSU), N. Gehrels (GSFC), on behalf of the Swift UVOT team. CORRECTION: The time at which the UVOT began observations of GRB050219b should read as 21:57:51 in GCN 3046 and GCN 3050. This was 52 minutes after the initial Swift BAT trigger (Cummings et al, GCN 3044), the delay being caused by the Earth-limb constraint. No new source was detected at the corrected XRT position (Racusin et al, GCN 3049), and the 3-sigma limiting magnitudes given in GCN 3050 still apply: Filter Lim_Mag Tot_Exposure(s) T_start (s) UVW2 ~ 22.16 1154 T+3120 UVM2 ~ 22.24 1435 T+3243 UVW1 ~ 22.23 940 T+3349 U ~ 20.74 100 T+3455 B ~ 20.9 100 T+3561 V ~ 19.41 100 T+3136 We caution that the instrument is not yet fully calibrated and that the magnitude limits presented here may need to be refined. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3064 SUBJECT: GRB 050219b: candidate NIR afterglow DATE: 05/02/24 22:27:28 GMT FROM: Paolo D'Avanzo at INAF-OAB P. D'Avanzo, D. Fugazza, S. Covino, G. Tagliaferri, D. Malesani, L.A. Antonelli, S. Campana, G. Chincarini, M. Della Valle, F. Fiore, L. Stella, F.M. Zerbi, on behalf of the MISTICI collaboration report : Optical and near-infrared monitoring of the field of GRB050219b (Cummings et al., GCN 3044) was performed at the ESO-VLT, with the FORS2 and ISAAC instruments respectively. Observations were carried out under a clear sky, starting 0.18 days after the GRB. The log is reported below. Mean date (UT) t-t0 (days) filter seeing (") ---------------------------------------------- Feb 20.062 0.18 R 1.0 Feb 21.062 1.18 R 1.0 Feb 21.088 1.21 Ks 0.5 Feb 24.024 4.14 Ks 0.5 ---------------------------------------------- t0 = Feb 19.879 UT (GRB trigger). In the refined XRT position and error circle (Burrows et al., GCNs 3043; Racusin et al., GCN 3049) we detect three sources in the Ks images: 1. RA: 05:25:15.99 Dec: -57:45:28.7 2. RA: 05:25:16.13 Dec: -57:45:30.5 3. RA: 05:25:15.59 Dec: -57:45:25.4 Source #2 and #3 do not exhibit significant variations (the latter being also present in the 2MASS catalogue). Source #1 is pointlike and is fading by 1.09 +- 0.19 mag in the Ks band between 1.21 and 4.15 days after the burst. We therefore identify this is the NIR afterglow of GRB050219b. The flux decay index (F = K*t^-delta) is delta = 0.81 +- 0.14. The candidate afterglow has a magnitude Ks = 21.47 +- 0.18 on Feb 24.02, based upon field calibration with standard stars. We caution that we get Ks = 16.45 +- 0.04 for the 2MASS star quoted above (source #3), which has a tabulated magnitude K=15.345 in the 2MASS catalog. In the R band, no source is detected at the position of the candidate afterglow, down to a limiting magnitude R~23, based on calibration against the USNO catalog. Further observations are planned at the VLT. This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3096 SUBJECT: GRB 050219b: Gemini/GNIRS near-infrared spectroscopy DATE: 05/03/16 00:47:10 GMT FROM: Edo Berger at Carnegie Obs E. Berger (Carnegie Observatories) and D.B. Fox (Caltech) report on behalf of the Carnegie-Caltech-NRAO collaboration: "On 2005, February 24.09 UT we obtained near-infrared spectra with GNIRS on the Gemini-south telescope of the NIR afterglow of GRB 050219b, identified in images from the Las Campanas 100-inch telescope (see also GCN 3064). As reported in GCN 3064 (also GCN 3052: UVOT limits), the NIR afterglow is significantly brighter than optical limits obtained contemporaneously, suggesting a large dust extinction or a high redshift (z>5) origin. Using Director's Discretionary time we obtained a total of 4800 sec on source in the cross-dispersed mode which covers the range of 1-2.5 microns in six echelle orders (R~1700). No continuum or emission lines were detected in the combined 2-d spectrum. We thank Phil Puxley, Gemini South Associate Director, for the allocation of DD time, and Claudia Winge for extensive help with the Phase I/II setup and the observations."