This file contains BOTH GRBs 060502A and 060502B. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5047 SUBJECT: GRB 060502: Swift detection of a burst with an optical counterpart DATE: 06/05/02 03:55:38 GMT FROM: Scott Barthelmy at NASA/GSFC V. La Parola (INAF-IASFPA), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), P. Romano (INAF-OAB), T. Sakamoto (NASA/ORAU), E. Troja (INAF-IASFPA) and D. E. Vanden Berk (PSU) report on behalf of the Swift Team: At 03:03:32 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 060502 (trigger=208169). Swift slewed immediately to the burst. The BAT on-board calculated location is RA,Dec 240.858, +66.595 {16h 03m 26s, +66d 35' 42"} (J2000) with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a roughly triangular shaped single peak starting at ~T-8 sec and lasting until ~T+20 sec. The peak count rate was ~2500 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 03:04:48 UT, 76 seconds after the BAT trigger. Ground analysis of the initial XRT data found a bright, uncatalogued, fading X-ray source located at RA(J2000) = 16h 03m 42.9s, Dec(J2000) = +66d 35' 57.4", with an estimated uncertainty of 3.9 arcseconds (90% confidence radius). This location is 98 arcseconds from the BAT on-board position, within the BAT error circle. The initial flux in the 2.5s image was 1.3e-09 erg/cm2/s (0.2-10 keV). UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 85 seconds after the BAT trigger. There is an 18.4 magnitude source that is not visible in the Digitized Sky Survey images, at J2000 coordinate 16h 03m 42.48s, +66d 36' 02.5" (240.9270, +66.6007). The position is 5.7 arcseconds from the center of the XRT error circle. This burst triggered BAT at the beginning of a Malindi telemetry downlink session and so the downlink of the TDRSS notices was delayed until the end of the pass (~18 min). //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5048 SUBJECT: GRB 060502: P60 Afterglow Confirmation DATE: 06/05/02 04:45:42 GMT FROM: S. Bradley Cenko at Caltech S. B. Cenko, E. O. Ofek (Caltech), and D. B. Fox (Penn State) report on behalf of a larger collaboration: We have imaged the field of GRB060502 (La Parola et al., GCN 5047) with the automated Palomar 60-inch telescope. Observations began immediately following astronomical twilight. The UVOT optical candidate is detected in individual 60 s R, g, and i' images and is cleary fading. We therefore confirm this object as the afterglow of GRB060502. We estimate the magnitude of the afterglow to be R ~ 19.8 approximately 40 minutes after the burst trigger (calculated with reference to several nearby USNO-B objects). Observations are continuing. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5049 SUBJECT: GRB060502: Super-LOTIS Observations DATE: 06/05/02 07:13:21 GMT FROM: Grant Williams at Steward Observatory G. G. Williams (MMTO), and P. A. Milne (Steward Observatory) on behalf of the Super-LOTIS Collaboration, report: The robotic 0.6-m Super-LOTIS telescope began observing the error box of GRB060502 (Swift Trigger 208169, GCNC 5047) at 03:20:46 UT, 1034 seconds after the burst (17.23 min; 33 seconds after the delayed GCN notice). Our initial observations include 5 x 10s exposures, 5 x 20s exposures, and 30 x 60s exposures, all in the R-band. Under thin cirrus we do not detect the Swift afterglow reported by La Parola et al. and Cenko et al. (GCN 5047 & 5048) in our earliest 60 second exposure to the following 3-sigma limiting magnitude estimated using nearby USNO-B1.0 stars: t_mid obs (UT) exp t (s) t-t_0 (s) Limit -------------------------------------------------------- 03:24:56 60 1284 R > 17.9 Additional observations and analysis, including image stacking, are ongoing. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5051 SUBJECT: GRB 060502: APO Spectroscopic Observations DATE: 06/05/02 10:12:43 GMT FROM: Hsiao-Wen Chen at U Chicago H.-W. Chen (U Chicago), R. McMillan (APO), A. Bender (U Colorado), D. York, and D. Lamb (U Chicago) report on behalf of a larger collaboration: "We observed the afterglow of GRB060502A reported by La Parola et al. (GCN 5047) and confirmed by Cenko et al. (GCN5048), using the Dual Imaging Spectrograph (DIS) with a 1.5-arcsec slit on the 3.5 m telescope at the Apache Point Observatory. The observations started at UT 05:52:33 on May 2, 2006, ~ 2.8 hours after the inital Swift/BAT trigger, and were carried out under a mean seeing condition of 1.3 arcsec in a sequence of two 1800-sec exposures. The final stacked spectrum covers the spectral range from 3800 Ang to 8500 Ang with a spectral resolution of 2.4 Ang per pixel, and appears to be featureless. The abundant fluxes observed below 4000 Ang and the lack of spectral discontinuity below 4500 Ang indicate that the GRB originated at redshift z < 2.2. We determine a tentative redshift for the GRB afterglow at z=0.099 +/0.001 based on the tentative identifications of CaII H&K absorption features at around 4322 and 4361 Ang. Further analysis is underway. This message may be cited." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5052 SUBJECT: GRB060502: Gemini spectroscopy DATE: 06/05/02 10:13:13 GMT FROM: Antonino Cucchiara at PSU A. Cucchiara (Penn State), P.A. Price (IfA, Hawaii), D.B. Fox, (Penn State), S.B. Cenko (SRL, Caltech) and B.P. Schmidt (RSAA, ANU) report on behalf of a larger collaboration: We have observed the optical afterglow of GRB 060502 (La Parola et al., GCN 5047, Cenko et al., 5048) with the GMOS instrument on Gemini North telescope. Observations consisted of 2 x 1800 sec exposures with the R400 grating, commencing at 2006 May 2.34 UTC. In the summed spectrum, we identify an absorption system consisting of Fe II, Mg II and Mg I at a redshift of z ~ 1.51. No other absorption or emission line systems are apparent. We acknowledge the rapid response effort of Gemini personnel that yielded these data. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5053 SUBJECT: GRB 060502: Swift-BAT refined analysis DATE: 06/05/02 13:50:00 GMT FROM: Takanori Sakamoto at NASA/GSFC A. Parsons (GSFC), L. Barbier (GSFC), S. Barthelmy (GSFC), J. Cummings (GSFC/ORAU), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (BYU-Idaho), H. Krimm (GSFC/USRA), M. Koss (UMD), C. Markwardt (GSFC/UMD), D. Palmer (LANL), T. Sakamoto (GSFC/ORAU), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), on behalf of the Swift-BAT team: Using the data set from T-119 to T+229 sec from the recent telemetry downlink, we report further analysis of BAT GRB 060502 (trigger #208169) (La Parola, et al., GCN 5047). The BAT ground-calculated position is (RA,Dec) = 240.941, 66.600 deg {16h 3m 45.8s, 66d 35' 59.5"} (J2000) +- 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 49%. The mask-weighted lightcurve shows a main peak starting at T-5 sec and ending at T+30 sec. The second weak peak follows in a duration of ~15 sec. T90 (15-350 keV) is 33 +- 5 sec (estimated error including systematics). The time-averaged spectrum from T-5.8 to T+42.0 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.43 +- 0.08. The fluence in the 15-150 keV band is 2.2 +- 0.1 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T-0.10 sec in the 15-150 keV band is 1.7 +- 0.2 ph/cm2/sec. Eiso is 5.8e+49 ergs (16.5 - 164.9 keV in the GRB rest frame) and 1.5e+52 ergs (37.7 - 376.5 keV in the GRB rest frame) using z = 0.099 (Chen et al. GCN 5051) and z = 1.51 (Cucchiara et al. GCN 5052) respectively. All the quoted errors are at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5054 SUBJECT: GRB060502: Swift-XRT refined analysis DATE: 06/05/02 15:17:44 GMT FROM: Eleonora Troja at INAF-IASFPA V. La Parola, E. Troja, V. Mangano (INAF-IASFPA), S. Campana (INAF-OAB), K. L. Page (U Leicester), J. Kennea, D.N. Burrows (PSU), on behalf of the Swift-XRT team. We have analyzed the first two orbit of data of GRB060502 (La Parola et al 2006, GCN 5047). The XRT data set consists of 71 s exposure in Windowed Timing (WT) mode followed by 355 s exposure in Photon Counting (PC) mode in the first orbit and 2.4 ks in the second orbit. The refined position of the source is RA (2000) = 16h 03m 42.9s Dec (2000) = 66° 35' 58.1" with an uncertainty of 3.7 arcsec (90% confinement). This position is only 1 arcsec from the one calculated from early downlinked data (La Parola et al 2006, GCN 5047), 5.1 arcsec from the UVOT afterglow position and 17.6" from the BAT refined position (Parsons et al. GCN5053). The 0.2-10 keV X-ray light curve shows an initial fast decay with slope -2.87 +/- 0.11 and a break at 252 +/- 17 s from the trigger followed by a second decay slope of -0.54 +/- 0.05. The WT spectrum (collected during the pre-break phase) can be fitted with a power law (photon index 2.3 +/-0.5) plus a soft thermal component (which can be modelled with a blackbody at 0.13+/-0.02 keV), with intrinsic absorption (0.45+/-0.15)e22 cm-2, assuming a redshift of 1.51 (Cucchiara et al. GCN5052). The PC spectrum after the break is fitted with an absorbed power law with photon index 1.99 +/-0.15 and intrinsic absorption (0.6+/-0.2)e22 cm-2. The Galactic absorption is 2.97e20 cm-2. With the present decay slope, the 0.2-10 keV flux at 24h after the trigger is expected to be ~2e-12 erg/s/cm-2 This Circular is an official product of the Swift XRT Team. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5055 SUBJECT: GRB 060502B: Swift detection of a short burst DATE: 06/05/02 18:08:11 GMT FROM: Scott Barthelmy at NASA/GSFC E. Troja (INAF-IASFPA), S. D. Barthelmy (GSFC), P. T. Boyd (NASA/GSFC), D. N. Burrows (PSU), J. R. Cummings (NASA/ORAU), N. Gehrels (NASA/GSFC), S. T. Holland (GSFC/USRA), S. D. Hunsberger (PSU), J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA), V. La Parola (INAF-IASFPA), V. Mangano (INAF-IASFPA), F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), T. Sakamoto (NASA/ORAU), G. Tagliaferri (INAF-OAB) and D. E. Vanden Berk (PSU) report on behalf of the Swift Team: At 17:24:41 UT, the Swift Burst Alert Telescope (BAT) triggered and located the short GRB 060502B (trigger=208275). Swift slewed immediately to the burst. The BAT on-board calculated location is RA,Dec 278.936, +52.632 {18h 35m 45s, +52d 37' 56"} (J2000) with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The TDRSS BAT light curve shows a single spike with a FWHM of less than 128 msec. The peak count rate was ~10000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began taking data at 17:25:51 UT, 70 seconds after the BAT trigger. The XRT on-board centroid algorithm did not find a source in the image, however analysis of downlinked data reveals a faint point source at the following coordinates: RA(J2000) = 18h 35m 45.9s, Dec(J2000) = 52d 37m 38.1s, with an estimated uncertainty of 10 arcseconds radius (90% containment). This position is 20 arcseconds from BAT localization. We note that the XRT position lies 2.5 arcseconds from an possible galaxy with R=18.5 in the APM-North catalogue (McMahon et al., 2000). UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 74.2 seconds after the BAT trigger. There is no detected new source in the rapidly available 2.7'x2.7' sub-image, to a limiting White magnitude of about 19.1. We are currently in the beginning of the Malindi downlink gap, so we will not have the full data set until at least 01:00 03/May/06 UT. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5056 SUBJECT: GRB 060502B: MASTER optical observations DATE: 06/05/02 19:34:26 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, V.Kornilov, N.Tyurina, A.Belinski, D.Kuvshinov, E.Gorbovskoy, A.Krylov, G.Borisov, A.Sankovich, V.Vladimirov, P.Gritsyk, S.Korobkin Sternberg Astronomical Institute, Moscow Union 'Optic' MASTER robotic system (http://observ.pereplet.ru) responded to GRB060502B (GRB_TIME is 2006-05-02 17:24:41.07, E. Troja et al. GCN5055) by unfiltered, BVR-filtered, spectral and high time resolution cameras. The first image was at 2006-05-02 17:25:50.11 UT, 69 s after the GRB time on the bright evening sky. The first images with more or less good limit was at 82 min after the GRB time at high air mass. The unfiltered image is calibrated relative to USNO A2.0 (0.8 R + 0.2 B). The robot not find OT-candidate in error box brighter then 16.0 (s/n=5) at Swift XRT position. This work is supported by RFFI 04-02-16411 grant. This message can be cited. Mailto: lipunov@sai.msu.ru //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5057 SUBJECT: GRB 060502B: Xinglong optical observation DATE: 06/05/02 20:40:39 GMT FROM: W.K. Zheng at NAOC M.Zhai, Y.L. Qiu, J.Y. Wei, J.Y. Hu, J.S. Deng(NAOC),X.F. Wang (THCA), K.Y. Huang (NCU), Y. Urata (Saitama Univ.) on behalf of EAFON report: "We have imaged the field of GRB 060502B (Troja et al. GCN 5055) with clear, R and I band using the 0.8m telescope at Xinglong Observatory. First imaging was started from 305 s after the trigger. The limiting magnitude is clear = ~ 20 (12 min after) and R=20.6 (60 min after) derived from USNO-B1.0 r catalog. No new source was detected brighter than the limits in the XRT error circle. Further analysis is in progress." This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5059 SUBJECT: GRB060502B: correction to XRT position DATE: 06/05/02 21:25:00 GMT FROM: Vanessa Mangano at INAF-IASFPA E. Troja (INAF-IASFPA), V. Mangano (INAF-IASFPA), J. Kennea (PSU), A. Moretti (INAF-OAB) on behalf of the Swift XRT team: A re-analysis of the XRT TDRSS data has led to a different position from the one issued with GCN 5055. The new estimated position for the candidate X-ray afterglow is: RA (2000) = 18 35 45.6 Dec (2000) = +52 37 54.2 with an uncertainty of 7 arcsec (90% confinement). We are still waiting for down-linked data for refined coordinates of the source. We apologize for the inconvenient. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5060 SUBJECT: GRB 060502A: TTT Observations DATE: 06/05/02 22:44:08 GMT FROM: Melissa Nysewander at UNC,Chapel Hill M. Nysewander, J. Harvey, A. Foster, D. Reichart, J. A. Crain, K. Ivarsen report on behalf of the UNC team of the FUN GRB Collaboration: Under the automated control of SkyNet, the 0.37-m TTT telescope, located outside of Fort Collins, Colorado, began observing the localization of GRB 060502A (Parola et al., GCN 5047) 65 seconds after the initial notification, and 17.8 minutes after the time of the burst in the V & Red filters. In our first 160-s exposure at a mean time of 19.1 minutes after the burst, we do not see the afterglow (Parola et al. GCN 5047, Cenko et al., 5048) down to a 3-sigma limiting magnitude of R ~ 17.5. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5062 SUBJECT: Short GRB 060502B: Tautenburg Observation DATE: 06/05/03 00:28:27 GMT FROM: Alexander Kann at TLS Tautenburg D. A. Kann, S. Klose & P. Ferrero (TLS Tautenburg) report: We observed the location of the short burst GRB 060502B (Troja et al., GCN 5055) with the Tautenburg 1.34m Schmidt telescope. Observations were taken under bad observing conditions (airmass 1.95, twilight, moonlight). The observation consisted of a single 900 sec exposure in the R band taken at a mid-exposure time of 20060502.8356, 0.1101 days after the burst. Due to the conditions, the image limit is shallow, with a 3 sigma limiting magnitude of 20.2. The Galaxy mentioned in GCN 5055 is clearly detected at a magnitude of R = 18.1 +/- 0.09 (measured vs. several surrounding USNO1.0B stars). We detect a possible additional source to the southeast of the center of the galaxy (but within the PSF in our image), at RA = 18:35:45.90, Dec.= +52:37:33.20 (errors +/- 0.5"), which could possibly be a superposed faint afterglow, reminescent of GRBs 050709 or 050724. But there seems to be a source here also in the DSS R image, so this identification is very unsure. Furthermore, we note that this galaxy is not included in the revised error circle (Troja et al., GCN 5059) any more, which would rule it out as a host galaxy altogether, unless it lies at low redshift and the progenitor has been ejected from the galaxy. Spectroscopy is encouraged. No source is detected at all within the revised error circle. We are grateful to S. Melnikov for observing time. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5063 SUBJECT: GRB060502B: Swift XRT Team refined analysis DATE: 06/05/03 02:15:10 GMT FROM: Vanessa Mangano at INAF-IASFPA E. Troja (INAF-IASFPA), V. Mangano (INAF-IASFPA), V. La Parola (INAF-IASFPA), D. N. Burrows (PSU) report on behalf of the Swift XRT Team: We have analyzed the first 10 ks of PC data of GRB060502B (Troja et al 2006, GCN 5055). The refined position of the source is RA (2000) = 18h 35m 45.65s Dec (2000) = +52d 37' 51.97'' with an uncertainty of 5.4 arcsec (90% containement). This position is only 2.2 arcsec from the corrected XRT position (Troja et al 2006, GCN 5059). The 0.2-10 keV X-ray light curve shows a decay behaviour with slope of -1.2 +/ 0.2. There are only 36 counts in the extraction region, that are not enough for a detailed spectral analysis. The estimated source flux, assuming a photon index of 2.0, is about 10^-13 ergs cm^-2 s^-1. If decaying at the present rate the source will reach the flux level of 1.5 x 10^-15 erg cm^-2 s^-1 (corresponding to a count rate level of 2.9 x 10^-5 counts s^-1) after one day. This Circular is an official product of the Swift XRT Team. [GCN OPS NOTE(03may06): Per author's request, the "only 4 arcsec" was changed to "only 2.2 arcsec".] //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5064 SUBJECT: GRB 060502B: Refined analysis of the Swift-BAT short burst DATE: 06/05/03 04:31:23 GMT FROM: Scott Barthelmy at NASA/GSFC G. Sato (ISAS), L. Barbier (GSFC), S. Barthelmy (GSFC), J. Cummings (GSFC/ORAU), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (BYU-Idaho), H. Krimm (GSFC/USRA), M. Koss (UMD), C. Markwardt (GSFC/UMD), J. Norris (GSFC), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), M. Stamatikos (GSFC/ORAU), E. Troja (INAF-IASFPA), J. Tueller (GSFC) on behalf of the Swift-BAT team: Using the data set from T-119 to T+183 sec from the recent telemetry downlink, we report further analysis of BAT GRB 060502B (trigger #208275) (Troja, et al., GCN 5055). The BAT ground-calculated position is RA,Dec = 278.949, 52.642 deg {18h 35m 47.7s, 52d 38' 32.5"} (J2000) +- 1.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 92%. The lightcurve consists of two spikes. The main peak starts at ~T-0.060 and has a FWHM of ~40 msec. Its rise is faster than the decay. There is also a possible second peak (a precurrsor) starting at T-0.3 sec with a FWHM of ~100 msec and a significance of only ~4 sigma. T90 (15-350 keV) is 90 +- 20 msec (estimated error including systematics). The lag analysis shows this burst to be cleanly in the short hard burst class (Norris and Bonnell, 2006, ApJ, accepted; see, Figure 3). Specifically, the measured lags for the main peak are: -4.0 ms +- 3.0 ms (15-25 keV vs. 50-100 keV) -0.2 ms +- 2.8 ms (25-50 keV vs. 100-350 keV) The time-averaged spectrum from T-0.05 to T+0.04 is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 0.92 +- 0.23. The fluence in the 15-150 keV band is 4 +- 0.5 x 10^-8 erg/cm2. The 1-sec peak photon flux measured from T-0.43 sec in the 15-150 keV band is 4.4 +- 0.6 ph/cm2/sec. All the quoted errors are at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5065 SUBJECT: GRB 060502B: AROMA optical observations DATE: 06/05/03 08:44:18 GMT FROM: Kazutaka Yamaoka at Aoyama Gakuin U I.Takahashi, T.Uehara, K.Yoshida, A.Kobayashi, K.Tanaka, Y.E.Nakagawa, S.Sugita, K.Yamaoka, A.Yoshida (AGU) report: The robot optical telescope, AROMA, at Aoyama Gakuin University (AGU) responded to GRB 060502B (Troja et al. GCN 5055). The observations started at 17:26:26 UT (105s after the GRB) by the 0.3m optical telescope with R-band filter located at the AGU campus in Sagamihara, Japan. No new source was found above the 3 sigma limiting magnitude of R~16 calibrated with USNO A2.0 by the preliminary routine analysis on the first 20 frames of image with 5s exposure each. The mean time of the data set corresponded to 319s after the burst. Further analysis is underway. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5066 SUBJECT: GRB 060502B: MDM Optical Observation DATE: 06/05/03 09:38:13 GMT FROM: Jules Halpern at Columbia U. J. P. Halpern (Columbia U.) and N. Mirabal (U. Michigan) report: "We observed the location of Swift short GRB 060502B (Troja et al., GCN 5055) in the R band on the MDM 1.3m telescope starting on May 03 08:22 UT, 15 hours after the trigger. A summed 45 minute exposure has a limiting magnitude of R~23.5. To this limit, there is a single object in the refined XRT error circle of Troja et al. (GCN 5063), at coordinates (J2000) 18h 35m 45.89s +52d 37' 56.2" (+/- 1") Its magnitude is R = 21.6 +/- 0.1, calibrated with Landolt standard stars, and it appears unresolved in seeing of 1.7". Further optical observations are encouraged. This message may be cited." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5068 SUBJECT: GRB 060502A: Swift/UVOT source detection DATE: 06/05/03 10:35:52 GMT FROM: Tracey Poole at MSSL T. S. Poole (UCL-MSSL), and V. La Parola (INAF-IASFPA) on behalf of the Swift/UVOT team. The Swift/UVOT began observing the field of GRB060502 (BAT Trigger=208169, V. La Parola, et. al, GCN 5047) at 03:04:56 UT, 84s after the BAT trigger. We detect a fading source with a calculated position of RA = 16:03:42.48 and Dec = +66:36:02.5 (J2000) in the V, B and White filters, and the summed UVW1 filter. The error in the coordinates of the UVOT source is +/- 0.56 arcsec (90% confidence). The position is 4.4 arcseconds from the centre of the XRT error circle reported by V. La Parola, et. al, (GCN 5054). Checks against the Digitized Sky Survey images yield no known source at this position on the sky. The calculated magnitudes of the first afterglow observations in the UVOT filters are given below. The limiting magnitudes are given to a 3 sigma limit. These values are not corrected for Galactic extinction; E(B-V) = 0.033. Filter T_range(s) T_exp(s) Magnitude Comments V 190-536 346 18.70 +/- 0.14 - source detection V 5092-5292 200 20.19 - 3 sigma upper limit B 4478-4678 200 20.04 +/- 0.16 - source detection B 5910-6110 200 20.91 +/- 0.34 - source detection U 4273-4473 200 20.84 - 3 sigma upper limit U 5706-5905 200 20.78 - 3 sigma upper limit UVW1 4069-4269 200 20.63 - 3 sigma upper limit UVW1 5501-5701 200 20.61 - 3 sigma upper limit UVW1 4069-5701 400 20.89 +/- 0.40 - source detection UVM2 3864-4064 200 20.85 - 3 sigma upper limit UVM2 5296-5496 200 21.03 - 3 sigma upper limit UVW2 4888-5087 200 21.60 - 3 sigma upper limit WHITE 84-184 100 18.50 +/- 0.07 - source detection WHITE 4682-4882 200 20.53 +/- 0.20 - source detection WHITE 6115-6314 200 21.22 - 3 sigma upper limit Where T_range is time post-trigger, and T_exp is the exposure time of the observation. A 6 arcsec radius was used for all filters. When summing the two UVW1 200s exposures we see a source detection above 3 sigma. This give a z upper limit of 1.9. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5069 SUBJECT: GRB 060502B: Swift/UVOT upper limits DATE: 06/05/03 10:37:39 GMT FROM: Tracey Poole at MSSL T. S. Poole (UCL-MSSL), and E. Troja (INAF-IASFPA) on behalf of the Swift/UVOT team. The Swift/UVOT began observing the field of GRB060502b (BAT Trigger=208275, E. Troja, et. al, GCN 5055) at 17:25:38 UT, 57s after the BAT trigger (which includes the 10s V filter settling exposure). No new source is detected at the XRT position (E. Troja, GCN 5063) in coadded images with any of the filters. The following 5-sigma magnitude upper limits are not corrected for Galactic extinction; E(B-V) = 0.044. Filter T_range(s) T_exp(s) 5sigma(mag) V 57-35329 3002 20.29 B 658-24560 1204 20.62 U 634-41112 3819 21.04 UVW1 610-40198 4038 21.29 UVM2 586-36126 3633 21.31 UVW2 686-34417 2259 21.29 WHITE 74-6845 619 20.49 Where T_range is time post-trigger, and T_exp is the exposure time of the observation. A 6 arcsec radius was used for all filters. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5070 SUBJECT: GRB060502A, optical observation DATE: 06/05/03 15:33:17 GMT FROM: Peter Garnavich at U of Notre Dame M. Hicken (CfA) and P. Garnavich (Notre Dame) Images of the field around GRB 060502A (La Parola et al., GCN 5047) were obtained with the FLWO 1.2m telescope and KepCAM beginning on 2006 May 2.23 (UT). Four R-band exposures of 120 and 180 seconds were combined and the optical afterglow (Cenko et al., GCN 5048) is detected but is faint. The mean time of the combined exposures is 2.77 hours after the burst. Using stars in the USNO-A2.0 for calibration, we estimate the brightness of the afterglow to be R=20.1 +/- 0.3 mag. Also using the USNO-A2.0 catalog we estimate the position of the afterglow to be RA=16:03:42.63 DEC=66:36:03.7 (J2000) with an error of 0.7" which is consistent with the Swift/UVOT position (Poole et al., GCN 5068). //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5071 SUBJECT: GRB 060502b: Gemini imaging and spectroscopy DATE: 06/05/03 17:52:27 GMT FROM: Edo Berger at Carnegie Obs E. Berger (Carnegie Observatories), S. B. Cenko and A. Rau (Caltech) report on behalf of a larger collaboration: "We used the GMOS instrument on the Gemini North Telescope to image the field of GRB 060502b (GCN 5064) and to obtain a spectrum of the object detected within the XRT error circle (GCN 5063) by Halpern and Mirabal (GCN 5066). We detect the latter object in a combined 1500 sec exposure with an r-band magnitude of about 21.8, suggesting that the object has not faded between the time of the MDM observation (15 hrs post burst) and our observation (17 hrs post burst). Moreover, a spectrum of the object reveals broad absorption bands centered on 5900, 6200, and 6700 A, which are typical of cool giants (a comparison to stellar spectra indicates a M2V - M4V classification). In addition to this star, we also identify a fainter and marginally extended object within the XRT error circle with r~24.7 mag located at (J2000): RA = 18:35:46.06 DEC= +52:37:51.46 with an uncertainty of about 0.3" in each coordinate. An image of the region centered on the XRT error circle is available at: http://www.ociw.edu/~eberger/grb060502b_gemini.gif Source "S1" is the object found by Halpern and Mirabal (shown here to be a star), and source "G1" is the faint galaxy discussed above." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5072 SUBJECT: GRB 060502B MDM Follow-up Observation DATE: 06/05/04 11:22:23 GMT FROM: Jules Halpern at Columbia U. J. P. Halpern (Columbia U.) and N. Mirabal (U. Michigan) report: "Following our initial report in GCN 5066, we continued observing the XRT location of Swift short GRB 060502B (Troja et al., GCNs 5055,5063) in the R band on the MDM 1.3m telescope on May 3 and 4 UT. In a summed 75 minute exposure centered at May 3 09:02 UT, we clearly detect the faint galaxy candidate "G1" seen in the Gemini North image of Berger et al. (GCN 5064) that was taken about 1.5 hours later. Observing on the following night, a summed 105 minute exposure centered at May 4 08:56 UT again shows "G1" at about the same magnitude. We measure R~23.9 for this object, somewhat brighter than Berger et al. (GCN 5064). MDM images of this field are posted at http://www.astro.columbia.edu/~jules/grb/060502b/ This message may be cited." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5073 SUBJECT: GRB 060502B: AROMA refined photometric calibration DATE: 06/05/04 19:15:10 GMT FROM: Kazutaka Yamaoka at Aoyama Gakuin U I.Takahashi, T.Uehara, K.Yoshida, A.Kobayashi, T.Koshiishi, K.Tanaka, Y.E.Nakagawa, S.Sugita, K.Yamaoka, A.Yoshida (AGU) report: After the previous report (GCN 5065), we carried out further photometric calibrations for the observations of the GRB 060502B field (Troja et al. GCN 5055, GCN 5059). We have taken 100 frames of R band image with 20s exposure each and photometric calibration was mede by every 20 frames by comparing with USNO A2.0 stars in the same field. The 3 sigma limiting magnitude of each combined image is as below. data set mean time time - burst[s] lim-mag R (3sigma) ====================================================== 1st 17:30:00 UT 319 16.12 +/-0.16 2nd 17:37:35 UT 774 16.26 +/-0.19 3rd 17:45:13 UT 1232 16.00 +/-0.05 4th 17:52:44 UT 1683 16.00 +/-0.02 5th 18:00:13 UT 2132 16.30 +/-0.02 //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5074 SUBJECT: GRB 060502B: optical observations DATE: 06/05/05 09:03:29 GMT FROM: Daniele Malesani at SISSA-ISAS,Trieste,Italy E.J.A. Meurs, S.D. Vergani, C. O'Maoileidigh (Dunsink Observatory), D. Malesani (SISSA), and R. Gualandi (Loiano Observatory), report: We observed the field of the short GRB 060502B (Troja et al. 2006, GCN 5055) with the 152 Cassini telescope located in Loiano, Italy, equipped with BFOSC. Observations were conducted under moderate weather conditions (passing cirrus), securing three 20-min exposures. The mean time was May 2.96198 UT (5.68 hr after the burst). The average seeing was 1.8". No source was detected inside the revised XRT error circle (Troja et al. 2006, GCN 5063) in the coadded frame. The limiting magnitude is R = 20.6 (3 sigma) based on the USNO catalog. This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5077 SUBJECT: GRB 060502b: Second epoch Gemini observations DATE: 06/05/06 02:43:27 GMT FROM: Paul Price at IfA,UH P.A. Price (IfA, Hawaii), E. Berger (OCIW), D.B. Fox (Penn State), S.B. Cenko and A. Rau (Caltech) report on behalf of a larger collaboration: We have obtained a second epoch of imaging with the Gemini North telescope of the XRT localisation of the short/hard GRB 060502B (GCN #5063). The observations commenced at 2006 May 4.43 UTC (1.7 days after the GRB), and consisted of 5 x 300 sec exposures in r'. These observations have better seeing and depth than our first epoch observation (2006 May 3.43 UTC, 0.7 days after the GRB; GCN #5071). Image subtraction does not reveal any variable sources within the XRT error circle. In particular, the galaxy ("G1") and source ("S1") identified in our previous observations have not appreciably changed in brightness. These observations place a limiting magnitude of any optical afterglow in our first epoch observation of approximately R ~ 24.3 mag, based on assuming R=17.5 mag for USNO-B1 star 426-035230 (RA,Dec = 278.92572,52.61611). We identify in the second epoch image an additional faint source ("S2") at R ~ 25.8 mag in the error circle at approximate coordinates: 18:35:45.86 +52:37:50.0 J2000 An image of the field is available at: http://www.ifa.hawaii.edu/~price/grb060502b.gif Note that the magnitude of the faint galaxy ("G1") in GCN #5071 is measured to be R ~ 23.8 mag in our first epoch observation, using the above calibration, consistent with the observation of Halpern & Mirabal (GCN #5072). We apologise for any inconvenience this error may have caused. We thank the Gemini North observing team for obtaining these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5093 SUBJECT: GRB060502B: improvement in the XRT afterglow position DATE: 06/05/09 08:16:10 GMT FROM: Eleonora Troja at INAF-IASFPA E. Troja (INAF-IASFPA), D. N. Burrows (PSU), and N. Gehrels (NASA/GSFC) report on behalf of the Swift XRT Team: We have improved the astrometry of the Swift XRT observation of the short hard burst GRB 060502B (Troja et al. 2006, GCN Circs. 5055, 5059, and 5063) using 28 serendipitous X-ray sources detected in the field during our 30 ks observation. We find 13 possible associations in the 2MASS or USNO 1.0B catalogs. Four of these could be random matches, based on simulations with 28 sources placed randomly within the XRT field of view. From the 13 possible associations, we selected 7 guide sources with offsets <~ 3 arcsec from the X-ray sources, and used them to derive an astrometry correction using the ccorr command in XIMAGE. We obtained shifts in the coordinates of DeltaRA=1.3 arcsec, DeltaDec=-0.6 arcsec. The final best position of the X-ray afterglow is: RA(J2000) = 18h 35m 45.74s Dec(J2000) = +52d 37' 52.47'' The uncertainty in the afterglow position on the detector is 2.0 arcsec. The RMS scatter in the offsets between the corrected X-ray source positions and the optical counterparts is 1.9 arcsec, giving us a 90% confidence error radius of 4.4 arcsec. This position is 1.0 arcsec from the previously reported XRT refined position (GCN 5063) and 3.1 arcsec from the candidate galaxy G1 (Price et al. 2006, GCN 5071). //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5184 SUBJECT: GRB060502b: optical observations DATE: 06/05/29 10:02:37 GMT FROM: Alexei Pozanenko at IKI, Moscow V.Rumyantsev (CrAO), R. Karimov (MAO), R. Salyamov (MAO), E. Pavlenko (CrAO), Yu. Efimov (CrAO), A. Pozanenko (IKI), M. Ibrahimov (MAO) on behalf of larger GRB follow up collaboration report: We observed the location of Swift short GRB060502B (Troja et al., GCNs 5055, 5059, 5063, 5093) in the R band with 1.5m telescope of Maidanak Astronomical Observatory (MAO) starting on May 02 22:43 (UT) (5.3 hours after the trigger) and Shajn 2.6m telescope of CrAO between May 03 (UT) 01:27 - 02:41 (8.6 hours after the trigger). Totally we obtained 6 images of 180 sec exposure with mean seeing ~0.95" in Maidanak 1.5m and 39 images of 60 sec exposure in CrAO observatory (seeing ~3"). In combined images we detect G1 galaxy mentioned by Berger et al. (GCN 5071) and Halpern et al. (GCN 5072) and do not detect S2 source (Price et al. GCN 5077). A photometry of G1 and S1 sources is based on USNO B1.0 star R=17.5 mag (USNO-B1 426-035230 RA, Dec = 278.92572,52.61611): Mid time Telescope Exp. G1 S1 Limiting (UT) sec mag mag mag May 02.954 MAO 1.5m 6È180 ~24.2 21.40 +/-0.10 23.6 May 03.086 CrAO 2.6m 39x60 23.7 +/-0.3 21.65 +/-0.05 24.1 Our brightness estimation of G1 is consistent with brightness estimations obtained in MDM 1.3 (T0+15 h) R~23.9 (Halpern et al. GCN5072) and in Gemini North (T0+17 h) R~23.8 (Price et al. GCN5077). The combined images can be found in http://grb.rssi.ru/GRB060502b This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5195 SUBJECT: GRB 060502A: Optical afterglow observations DATE: 06/06/02 15:06:26 GMT FROM: Pall Jakobsson at U Hertfordshire Pall Jakobsson (Univ. of Hertfordshire), Erik Zackrisson, Janne Holopainen (Tuorla Observatory), Genoveva Micheva (Stockholm Observatory), Brian L. Jensen, Johan P. U. Fynbo and Jens Hjorth (DARK, NBI) report: Using MOSCA on the 2.56-meter Nordic Optical Telescope, we obtained 3*300 s R-band images of the GRB 060502A field (La Parola et al., GCN#5047) on May 3.21 (1.08 days post burst). At the location of the optical afterglow (Pool et al., GCN#5068), 0.7 arcsec outside the XRT borders (La Parola et al., GCN#5054), we detect a source with R = 22.5. Combined with the R-band magnitude reported by Hicken & Garnavich (GCN#5070), this implies a decay slope of alpha = 1.0. An image of the field is shown at: http://star-www.herts.ac.uk/~palli/grb060502A/grb060502A.jpg //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5238 SUBJECT: GRB 060502B: A Bright Early-type Galaxy as Putative Host of the Short Burst DATE: 06/06/07 10:36:49 GMT FROM: Josh Bloom at UC Berkeley GRB 060502B: A Bright Early-type Galaxy as Putative Host of the Short Burst J. S. Bloom, D. Perley, D. Kocevski, N. Butler (UC Berkeley), J. X. Prochaska (UCO/Lick), and H.-W. Chen report: On 31 May 2006 UT, using Keck I (+LRIS), we obtained spectra of a bright red extended source ("G*"; RA, DEC J2000 = 18:35:45.7, +52:37:37) that is 11.2 arcsec South of the southern edge of the revised XRT error circle (Troja et al. GCN 5093). Strong absorption features, which we identify as Ca II H+K, indicate a redshift for this early type galaxy of z=0.287. Weak [OII] emission can be seen indicating some low level of active star formation. We advance the hypothesis that this galaxy is the host of short burst GRB 060502B (Troja et al. GCN 5055) based on several points: 1. The galaxy is a massive early-type similar to the putative hosts of 050509B [1] and 050724 [2]. 2. The redshift inferred of the hosts of 050509b (z=0.225) and 050724 (z=0.258) are remarkably similar to that of G* indicating comparable energetics of the respective bursts. 3. At the redshift of z=0.287, the burst location would be between 47 - 67 kpc in projection from the center of the putative host, similar to the offset (39 +/- 13 kpc) inferred for 050509b. There are viable progenitors scenarios (e.g. degenerate binary mergers) where bursts occur at such distances from their birthsite. 4. Weak X-ray afterglow and no detected optical afterglow would seem to indicate a low density circumburst environment, as would be expected if the GRB originated far from the progenitor birthsite. We recognize the difficulty of now confirming this hypothesis but note that in the striking similarity of the host, redshift, afterglow, and offset configuration to GRB 050509b, these observations and inferences have a priori precedent." A false color image will be posted at: http://astro.berkeley.edu/~jbloom/grb060502B_color_keck1.gif This message may be cited. [1] Bloom et al. 2006ApJ...638..354B (astro-ph/0505480); Gehrels et al. 2005Natur.437..851G (astro-ph/0505630) [2] Berger et al. Nature 438 (2005) 988-990 (astro-ph/0508115)