Contains A and B GCN OPS NOTE (25may05): The first GCN/Swift Notices on this burst (050525A) were delayed by ~6 min after the BAT trigger because the burst happened during a telemetry down-link playback session (to Malindi) and the TDRSS real-time capability is disabled during this ~13 min interval. All the TDRSS messages are buffered on board the s/c during a playback, and when the playback has completed, TDRSS r-t is re-enabled, and the messages come down. They are then immediately processed by GCN (as always) and distributed to the client list (as per their filtering critria and distribution method, as always). //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3465 SUBJECT: GRB 050525A: ROTSE-III Detection of Possible Counterpart DATE: 05/05/25 00:41:33 GMT FROM: Eli Rykoff at U of Michigan/ROTSE E.S. Rykoff (U Mich), S.A. Yost (U Mich), H. Swan (U Mich), report on behalf of the ROTSE collaboration: ROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia, responded to GRB 050525A (Swift trigger 130088). The first image was at 00:08:56.7 UT, 363.5 s after the burst (8.7 s after the GCN notice time). The unfiltered images are calibrated relative to USNO A2.0. We detect a 14.7 magnitude, fading source at: 18:32:32.76 +26:20:22.65 (J2000) start UT mag mlim(of image) ---------------------------------- 00:08:56.7 14.7 15.4 This source is not visible in DSS (second epoch), 2MASS or the MPChecker database. Continuing observations are in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3466 SUBJECT: GRB 050525: Swift Detection of a Bright, Possibly Short Burst DATE: 05/05/25 01:36:14 GMT FROM: David L. Band at NASA/GSFC D. Band (GSFC/UMBC), J. Cummings (GSFC/NRC), M. Perri (ASDC), S. Holland (GSFC/USRA), D. N. Burrows (PSU), N. Gehrels (GSFC), J. E. Hill, J. A. Kennea, S. Hunsberger (PSU), C. Markwardt (GSFC/UMD), D. Palmer (LANL) on behalf of the Swift Team. At 00:02:53 UT, the BAT instrument on the Swift spacecraft triggered (trigger=130088) and located GRB 050525. The BAT on-board calculated location is RA,Dec 278.144 , +26.340 (18h 32m 35s +26d 20' 23") (J2000) with an uncertainty of 3 arcmin (radius, 3-sigma, including systematic uncertainty). This is a very bright burst, yielding about 1500 counts over background in 64 ms (preliminary) in the 25-100 keV range in the BAT instrument. This would correspond to a rate of 10 counts/sec/cm2 in that 64 ms interval, but the peak rate in a later interval may be greater. Although light curves are not yet available, the BAT rate trigger continued to evaluate different timescales while data from the first 64 ms was being imaged. The merit parameters indicate that the highest significance rate trigger is for a 1 second interval, consistent with a short burst. More details will be available after the full data pass. The XRT was pointed promptly at the burst and took an image at 00:04:58 UT (125 s after the BAT burst trigger). The XRT found a bright X-ray source near the center of the field of view, with position RA(J2000) = 18h 32m 32.3s Dec(J2000) = +26d 20' 17.5" We estimate an uncertainty of about 6 arcseconds radius (90% containment). This position is 31 arcseconds from the BAT position and 8 arcseconds from the ROTSE position (Rykoff et al, GCN 2465). We caution that the XRT is in the middle of engineering tests and is in an unusual mode. While the X-ray afterglow looks unusually strong, there are also indications that the XRT instrument configuration is abnormal due to the tests being performed. The XRT position is outside of the UVOT-TDRSS image. Analysis of the UVOT data will take place after the next full data pass. This is a bright burst that appears to be in the short category; the Sun and moon angles are conducive for optical observations. Followup observations are strongly encouraged. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3467 SUBJECT: GRB 050525 - Very Bright, Not Short DATE: 05/05/25 02:14:26 GMT FROM: Craig Markwardt at NASA/GSFC/UMD C. Markwardt (GSFC/UMD), S. Barthelmy (NASA/GSFC), L. Barbier (GSFC), J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (UMD), H. Krimm (GSFC/USRA), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), M. Suzuki (Saitama), J. Tueller (GSFC) on behalf of the Swift-BAT team: GRB 050525 (Swift trigger 130088) was observed by Swift BAT. At the present, only rate data are available. This initial data indicate that the burst was very intense (peak rate of 80,000 ct/s above background). The light curve consists of at least two ragged peaks, with a total duration of approximately 10 seconds (15 - 200 keV). Thus, this is not a short burst as initially speculated (Band et al. GCN #3466), but it is one of the brightest bursts of the year. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3468 SUBJECT: GRB050525: ROTSE-III Refined Analysis DATE: 05/05/25 04:09:26 GMT FROM: Eli Rykoff at U of Michigan/ROTSE E.S. Rykoff (U Mich), S.A. Yost (U Mich), H. Swan (U Mich), R. Quimby (U Texas), report on behalf of the ROTSE collaboration: ROTSE-IIIc, located at the H.E.S.S. site in Namibia, and ROTSE-IIId at the Turkish National Observatory in Turkey responded automatically to Swift GRB 050525 (GCN 3466, 3467). Our first 5-s exposure from ROTSE-IIIc begain at 00:08:56.7 UT; the response in Turkey was delayed approximately 30 minutes due to bad weather. The images in Namibia were affected by clouds passing through the images. We confirm the fading nature of the afterglow reported in GCN 2465. The afterglow is well detected in images from both ROTSE-IIIc and ROTSE-IIId. The afterglow is 9" (3 pixels) from a 17.2 magnitude USNO star, which affected our initial position estimate. The revised position is: 18:32:32.6 +26:20:23.5 (J2000) with an uncertainty of ~1". We note that this is 7.2" from the XRT position reported by Band et al (GCN 2465). We have measured the afterglow flux with our PSF fitting software and have found that the early lightcurve is fading with a slow power-law decline with index ~-0.5, with a peak of 15.1+/-0.1 at 601s post-burst. The images are unfiltered and calibrated relative to USNO B1.0 R-band magnitudes. This bright afterglow with a slow decline should still be bright for follow-up spectroscopy. An image of the afterglow and burst field from ROTSE-IIId is available at: http://www.rotse.net/grb_reports/050525_btab.html //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3469 SUBJECT: GRB 050525: observatons of the optical afterglow DATE: 05/05/25 04:29:31 GMT FROM: Daniele Malesani at SISSA-ISAS,Trieste,Italy D. Malesani (SISSA), S. Piranomonte, F. Fiore (INAF/OARm), G. Tagliaferri, D. Fugazza (INAF/OABr), and R. Cosentino (INAF/TNG), report on behalf of a larger collaboration: We imaged the field of the bright GRB 050525 (Band et al., GCN 3466; Markwardt et al., GCN 3467) with the Italian 3.6m TNG. Observations were performed under good observing conditions (seeing ~1.1"), even if close to the bright Moon. The object reported by Rykoff et al. (GCNs 3465, 3468) is clearly detected in a single R-band image (2 min exposure) starting on 2005 Apr 25.07138 UT, 1.7 h after the GRB. Based on several nearby USNO stars, its magnitude is R ~ 17.4. We thus confirm the fading behaviour of this object. This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3470 SUBJECT: GRB 050525: Optical observation DATE: 05/05/25 04:44:38 GMT FROM: Ken ichi Torii at RIKEN K. Torii (Osaka U.) and Matt BenDaniel (http://Slooh.com) report: "The error region of the bright GRB 050525 (Band et al. GCN 3466; Markwardt et al. GCN 3467) was observed with the Slooh 14 inch f/6.3 telescope at Observatorio del Teide in the Canary Islands. The observation started at 2005 May 25, 00:50 UT (47 minutes after the burst) and a 30 s exposure in each of red, green, and blue filter was obtained. We stacked the three frames and compared it with the DSS frames. As a result of the preliminary analysis, we note a 3.3-sigma enhancement at position (R.A., Dec.) = (18:32:32.65 +26:20:24.5) (J2000, 1.3" uncertainty) with R~16.6 (USNO-A2.0 magnitude). This is 8".4 away from the Swift XRT position (GCN 3466) while it agrees with the refined position (Rykoff et al. GCN 3468) for the optical afterglow candidate (Rykoff et al. GCN 3465)." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3471 SUBJECT: GRB 050525, infrared observations DATE: 05/05/25 08:55:01 GMT FROM: Peter Garnavich at U of Notre Dame J. Rosenberg (CfA) and P. Garnavich (Notre Dame) We imaged the field of GRB 050525 (Band et al. GCN 3466) and the optical afterglow reported by Rykoff et al. (GCN 3465) with the 1.2m telescope of the Fred Whipple Observatory and Stelircam infrared imager. Imaging in J and K' began on May 25.22 (UT). Quick reduction of the K' data shows a new source not visible in the 2MASS K image at 18:32:32.61 +26:20:22 +/-1.0" (J2000) based on the USNO A-2.0 catalog. This is in agreement with the position provided by Rykoff et al. (GCN 3468) and Torii & BenDaniel (GCN 3470) given their quoted errors. The brightness is roughly K'=14. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3472 SUBJECT: INTEGRAL detection of GRB 050525 DATE: 05/05/25 09:16:08 GMT FROM: Sandro Mereghetti at IASF/CNR D. Gotz, S. Mereghetti (IASF, Milano), N. Mowlavi, S. Shaw, M. Beck (ISDC, Versoix), J. Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team and N. Lund (DSRI, Copenhagen) on behalf of the ISWT report: Offline analysis of the IBAS data showed that GRB 050525 discovered by Swift (Band et al. GCN 3466, Markwardt et al. GCN 3467), has been detected also by the IBIS/ISGRI instrument on board INTEGRAL. The burst occurred at an off-axis angle of 14.7 degrees, very close to the edge of the IBIS/ISGRI field of view, and illuminated through the coded mask only 6% of the detector surface. The preliminary value of the peak flux is 33 photons (3.2E-6 ergs)/cmsq/s (1 sec integration time, 20-200 keV). Owing to a small gap caused by telemetry saturation, we can only derive a lower limit on the fluence of 144 photons (1.2E-5 ergs)/cmsq (12 s integration time, 20-200 keV). A plot of the multi peaed light curve is posted at: http://ibas.mi.iasf.cnr.it/IBAS_Results.html This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3473 SUBJECT: GRB 050525: TAROT observations of the early afterglow DATE: 05/05/25 10:01:39 GMT FROM: Jean-Luc Atteia at Lab d Astrophys.,OMP,Toulouse Klotz, A. (CESR-OMP), Boer M. (OHP), and Atteia, J.L. (LAT-OMP) report: We imaged the entire field of GRB 050525 detected by SWIFT (Band et al. GCNC 3466) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. Observations started at 00:08:52s UT, 4 seconds after the GCN notice, and 6 min after the GRB. The field had an elevation of 62 degrees above horizon at the begining of the observations. The afterglow reported by Rykoff et al. (GCNC 3465) is clearly seen in TAROT images, with a magnitude R=15.1, 6 minutes after the GRB, and R=17.1, 108 minutes after the GRB. The unfiltered TAROT images are calibrated relative to R-band magnitudes in the USNO A1 Catalog. Further information, including a light-curve of the afterglow during the first two hours after the GRB can be found at the following address: http://www.cesr.fr/~klotz/grb050525/ This notice can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3474 SUBJECT: Konus-Wind observation of GRB 050525 DATE: 05/05/25 11:28:56 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and T. Cline on behalf of the Konus-Wind team report: A long bright GRB 050525 (Swift-BAT trigger=130088: GCN 3466,3467) triggered Konus-Wind at 176.704 s UT (00:02:56.704). As observed by Konus-Wind, it had a duration of ~11.5 s, fluence (7.84 +/- 0.06)10-5 erg/cm2, peak flux on 16-ms time scale (8.7 +/- 0.7)10-6 erg/cm2 s (both in the 20 keV - 1 MeV energy range). In ~2800 s after trigger, Konus-Wind detected even more intense burst. Because it was detected during data readout, only time history in the G2 window (74-295 keV) with 3-s time resolution is available. It had a duration of ~20 s and fluence 25100 counts in 74-295 keV energy range (the fluence of the trigger burst was 8500 counts in the same energy range). Assuming it had the same spectrum as the trigger burst, the energy fluence can be estimated as ~2.3x10^-4 erg/cm2. Whether the second burst relates to the first one or it is different GRB accidentaly registered close to the trigger burst can be clarified by data from other instruments (but the chance to register two very bright bursts so close to each other seems to be poor). The time-integrated spectrum of the GRB 050525 is well fitted by a power law with exponential roloff model: dN/dE ~ E^alpha exp(-E/E0) with alpha = -1.10 +/- 0.05, and E0 = 93.6 +/- 5.3 keV. The peak energy Ep = 84.1 +/- 1.7 keV. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3475 SUBJECT: Swift/UVOT UV and optical detections of GRB 050525 DATE: 05/05/25 12:29:37 GMT FROM: Alexander Blustin at MSSL-UCL S. Holland (GSFC), D. Band (GSFC/UMBC), A. Blustin, S. Rosen (MSSL), P. Roming (PSU), P. Schady (MSSL/PSU), K. Mason (MSSL), C. Gronwall (PSU), A. Breeveld (MSSL), T. Poole, C. James, K. McGowan, M. de Pasquale (MSSL) S. Hunsberger, C. Pagani, P. Brown, M. Ivanushkina (PSU), B. Hancock, T. Kennedy (MSSL), P. Broos, S. Koch (PSU), P. Smith, H. Huckle (MSSL), M. Still, P. Boyd, W. Landsman (GSFC), J. Nousek (PSU), N. Gehrels (GSFC) on behalf of the Swift UVOT team. Swift/UVOT has detected GRB 050525 in all of its UV and optical filters. Using data from 65 seconds after the burst, we obtain the following magnitudes from images summed between the T_start and T_stop times in the table: Filter Magnitude Exp (s) T_start T_stop V 14.97 +/- 0.02 287 65 1292 B 16.53 +/- 0.03 188 224 1084 U 15.32 +/- 0.03 98 90 979 UVW1 15.63 +/- 0.04 98 196 2046 UVM2 15.75 +/- 0.06 98 182 952 UVW2 16.62 +/- 0.05 188 952 1189 Where T_start and T_stop are in seconds after the trigger (Band et al. GCN 3466). The magnitudes are based on preliminary zero-points, measured in orbit, and will require refinement with further calibration. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3476 SUBJECT: Subject : GRB 050525: pseudo-redshift DATE: 05/05/25 12:50:03 GMT FROM: Jean-Luc Atteia at Lab d Astrophys.,OMP,Toulouse J-L. Atteia & A. Pelangeon (LAT-OMP) report: Taking into account the spectral parameters of GRB 050525 provided by Golenetskii et al. (GCNC 3474), we have computed its pseudo-redshift, using the method described in Atteia, 2003, A&A, 407, L1. We find a pseudo-redshift pz=0.36 +/- 0.1 We thank S. Golenetskii et al. for quickly providing the spectral parameters of this GRB. This notice can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3477 SUBJECT: GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A DATE: 05/05/25 13:15:23 GMT FROM: Sandro Mereghetti at IASF/CNR S. Mereghetti, D. Gotz (IASF, Milano), N. Mowlavi, S. Shaw, M. Beck (ISDC, Versoix), J. Borkowski (CAMK, Torun), A. von Kienlin, A. Rau, G. Lichti (MPE, Garching) on behalf of the IBAS Team report: The bright event seen by Konus/Wind about 2800 s after GRB 050525 and reported in GCN 3474 (Golenetskii et al. 2005) has also been detected by the Anti-Coincidence Shield of the SPI instrument on board INTEGRAL, starting at 00:49:50 UT and lasting about 16 seconds. At that time the position of GRB 050525A (GCN Circ. 3466, 3467, 3472) was inside the field of view of the IBIS imaging instrument. No signal was detected from this direction, indicating that the event at 00:49:50 UT is not related with GRB 050525A and is most likely another bright GRB. This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3478 SUBJECT: GRB050525: Optical observations DATE: 05/05/25 14:07:59 GMT FROM: Aaron Price at AAVSO D. T. Durig (Cordell-Lorenz Observatory, University of the South), A. Oksanen (Nyrola Observatory), C. Pullen (AAVSO) and A. Price (AAVSO) report on behalf of the AAVSO International High Energy Network on optical observations of GRB050525 (GCN #3466; Band et al.): An afterglow candidate is found at the location reported by Rykoff et al. (GCN #3468) and Band et al. (GCN #3465). At 08:13 UT it is detected at an unfiltered magnitude of 18-19 (fading over 100 mins centered on 08:13UT). The USNO star near 18 32 34.5 +26 20 24 can not completely be resolved from the afterglow candidate. Full details and FITS image URL is below. Name: Dr. Douglas T. Durig email: ddurig@sewanee.edu Observer: Dr. D. T. Durig ( CLW01) Site: Cordell-Lorenz Observatory Location: Sewanee, Tenn., USA LatitudeLongitude: 35 12 N 85 55 W Elevation: 600 m Scope: SCT 0.30 m ScopeFocalRatio: f/5.8 1765 mm CCDVendor: SBIG STL-1001E CCDDetector: KAF 1001E CCDSize: 1024x1024 CCDPixelScale: 2.8 CCDFOV: 48x48 full, 12x12 quarter frame cropped Object: GRB050525 ObsDate: 2005 05 25 ObsMidPointTime: 08 13 25 TimePerFrame: 120 sec NumberOfFrames: 75 Filters: CR Processing: dark, flat, register, co-add, 1/4 frame crop Seeing: 5-6 arc sec LimitingMag: 19.5-20 ??? Sky: very clear but breezy with Bright Moonlight afterglowmag: 18-19 afterglowerr: 1 compstars: 1300 UCAC ref stars in full frame Report: The USNO star near 18 32 34.5 +26 20 24 can not completely be resolved from the afterglow candidate, but I do see it fade by around 1 mag over a little over 100 min by summing a series of 30 consecutive 120 sec exposures. I get a measured position of 18 32 33.9 +26 20 23 and 18 mag at 7:23 UT falling to 19 mag at 9:03 UT, but this includes some contribution from the USNO star. comments: UT dec.day CR mag 7:23:28 25.30796 18.0 7:40:09 25.31955 18.2 7:56:43 25.33105 18.3 8:13:25 25.34265 18.3 8:30:10 25.35428 18.3 8:46:49 25.36584 18.6 9:03:28 25.37741 19.0 A FITS image has been uploaded to ftp://ftp.aavso.org/grb/Dr.DouglasT.Durig_GRB050525_2453516.00275_.fits The AAVSO thanks the Curry Foundation for their continued support of the AAVSO International High Energy Network. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3479 SUBJECT: GRB 050525A: Swift-BAT refined analysis DATE: 05/05/25 15:20:37 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift J. Cummings (GSFC/NRC), L. Barbier (GSFC), S. Barthelmy (GSFC), M. Chester (PSU), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), F. Marshall (GSFC), T. Mitani (ISAS), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), M. Suzuki (Saitama), J. Tueller (GSFC), on behalf of the Swift - BAT team: At 00:02:53 UT Swift-BAT detected GRB 050525A (trigger=130088) (GCN Circ 3466, Band, et al.). The refined BAT ground position is (RA,Dec) = 278.140,+26.344, [deg; J2000] {18:32:34, +26:20:38} +- 0.5 arcmin, (95% containment). This position is consistent with the reported optical transient positions to within 20 arcsec (GCN Circ 3468, Rykoff et al.; GCN Circ 3470, Torii et al.). The image significance is 148 sigma, making GRB 050525 the most significant BAT-imaged GRB to date. The burst was 26 degrees off axis, and the partial coding fraction was 85%. The mask-weighted light curve shows two peaks with duration of 2 and 5 seconds respectively. Each peak has two sub-pulses, which become more distinct at higher energies. T90 is (8.8 +- 0.5) seconds and T50 is (5.2 +- 0.5) seconds (15-350 keV; estimated errors include systematics). The spectrum has significant curvature, and is not consistent with a single power law model. Fitting to a cut-off power law yields a low-energy photon index of 1.0 +- 0.1, Epeak is 79 +- 4 keV. Fitting to a "Band" GRB spectral model yields the same spectral parameters, but the "beta" index is unconstrained. Chi2 for the Band model is the same as for the cutoff power law. The fluence in the 15-350 keV band is (2.0 +- 0.1) x 10^-5 erg/cm2. The 1-s peak photon flux, starting at T0+1.63 second in the 15-350 keV band is (48 +- 1) ph/cm2/s. All the quoted errors are at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3480 SUBJECT: GRB 050525A: BOOTES simultaneous optical observations DATE: 05/05/25 16:48:14 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia A. de Ugarte Postigo, M. Jelinek, J. Gorosabel, S. Guziy (IAA-CSIC Granada), P. Kubanek, R. Hudec (ASU-CAS, Ondrejov), S. Vitek (FEL-CVUT Praha), T. J. Soria, R. Fernandez (EELM-CSIC Malaga), J. Fabregat (Univ. de Valencia) and A. J. Castro-Tirado(IAA-CSIC), report: "The BOOTES-1 and BOOTES-2 very wide field cameras, located at INTA- CEDEA (Huelva, Spain) and EELM-CSIC (Malaga, Spain) respectively, and distant 200 km each other, observed the region of the sky containing the SWIFT/BAT error box for GRB 050525 (Band et al. GCN 3466, Markwardt et al. GCN 3467, Cummings et al. GCN 3469) as part of their routine observing schedules. 30 s exposures started simultaneously at 00:03:00 UT (7 s after the onset of the 10 s long burst), with the following frame starting at 00:04:00 UT (i.e. covering the late part of the event). A limiting (unfiltered) magnitude of 9.0 is derived for any prompt optical flash arising from this particular GRB. Images are posted at: http://www.iaa.es/~deugarte/GRBs/050525/GRB050525_wide.gif ". //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3481 SUBJECT: GRB 050525: BART optical observation DATE: 05/05/25 18:21:49 GMT FROM: Martin Jelinek at Inst.Astrophys.Andalucia,Granada Martin Jelinek (IAA CSIC Granada, Spain), Petr Kubanek, Martin Nekola and Rene Hudec (ASU AV CR Ondrejov, Czech Republic) report: The robotic telescope BART located at Astronomical Institute in Ondrejov, Czech Republic, observed the errorbox of the GRB050525 (Band et al. GCN 3466, Markwardt et al. GCN 3467, Cummings et al. GCN 3469) with it's Wide-field camera. First exposure started 18s after issuing the GCN alert (and 6m13s after the GRB onset). Co-add of first ten minutes of observation reveals the OT reported by Rykoff et al. (GCN 3468) at the detection limit of the image, which is V=15.5 according to our callibration made against GSC-1.2. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3483 SUBJECT: GRB 050525a: Gemini/GMOS Spectra DATE: 05/05/25 21:04:19 GMT FROM: Josh Bloom at Harvard/CFA R. J. Foley (UCB), H.-W. Chen (MIT), J. Bloom (UCB), J. X. Prochaska (UCSC) report: "We obtained a 5x1800 sec dithered exposures of the optical candidate (GCN 3465) of GRB 050525 with GMOS on the Gemini-North telescope starting at 2005 May 25.43 UT. We measure a redshift of z = 0.606, which we assume to be the redshift of the host galaxy, based on [O III] 5007 and H beta emission and Ca H&K and Ca I 4228 absorption. There is perhaps very faint [O II] emission. Further analysis is underway. This notice may be cited." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3484 SUBJECT: GRB 050525, spectral lag pseudo-redshift DATE: 05/05/25 22:19:26 GMT FROM: Jay Norris at NASA-GSFC/LHEA J. Norris, S. Barthelmy, N. Gehrels (GSFC), J. Cummings (GSFC/NRC), D. Band (GSFC/UMBC), L. Barbier (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), A. Parsons (GSFC), J. Tueller (GSFC) Analysis of the Swift/BAT light curves, between channels 100-350 keV and 25-50 keV, yields an estimate of the spectral lag of 0.124 +- 0.006 seconds for GRB 050525 (GCN 3466, Band et al.; (GCN 3479, Cummings et al.). Assuming the lag-luminosity relation (Norris et al. 2000, ApJ, 534, 248), using the Band model spectral parameters measured during the 1-second peak of the burst's light curve -- alpha = -1.0, beta = -8.9, Epeak = 79 keV, and the 1-second peak flux, 48 photon/cm^2/s, 15-350 keV -- we estimated a spectral-lag pseudo redshift of z = 0.72 +- 0.15, in broad agreement with the spectroscopic redshift, z = 0.606, reported by Foley et al. (GCN 3483). Uncertainty in the high-energy spectral shape, and the difference between the BATSE and BAT bandpass dependences of the lag-luminosity relation on peak flux, combine to require the error of order delta_z = 0.15. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3485 SUBJECT: GRB050525: Super-LOTIS observations DATE: 05/05/26 00:23:27 GMT FROM: Peter A. Milne at super-LOTIS P.A.Milne, G.G.Williams (Steward Obs), H.-S.Park (LLNL), on behalf of the Super-LOTIS GRB team report: We observed the field of GRB 050525 (SWIFT trigger 130088) starting at UT=06:02:41 (05:59:48 after the burst), with the 0.6m Super-LOTIS telescope at Kitt Peak, AZ. We obtained 20 x 30-sec images in each of the R,V and I filters. Observing conditions were affected by thin clouds in addition to the bright moon. Inspection of the three resulting co-added images reveals no source brighter than our limitting magnitude at the location of the candidate optical counterpart first reported by Rykoff et al. (GCN 3465,3468). Comparisons were based upon the DSS2 image and the afterglow finders provided by the ROTSE-III and TAROT collaborations. We report upper limits of: filter upper limit R 06:16 17.5 V 06:47 17.5 I 07:18 18.0 These values can be compared with the unfiltered detections reported by Durig et al. (GCN 3478). The upper limits are based upon three stars in the USNOB catalog, 1163-0325237, 1163-0325216, 1163-0325240. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3486 SUBJECT: GRB 050525 : Lulin optical afterglow observations DATE: 05/05/26 07:00:28 GMT FROM: Kuiyun Huang at IANCU GRB 050525 : Lulin optical afterglow observations P.S. Chiang (NCKU), K.Y. Huang, W.H. Ip (NCU), Y. Urata(RIKEN), Y. Qiu (BAO), Y.Q. Lou (THCA) on behalf of EAFON report: " We have imaged the GRB 050525 optical afterglow position reported by Rykoff et al.(GCN 3468) and Torii et al. (GCN 3470) using 1.0-m telescope at Lulin Observatory, Taiwan. The afterglow was detected at LOT images. The R band magnitude of afterglow is about 21.3 +/-0.1 around 17.74 hours after burst ( exposure time 300sec x 4) which compared with USNOB-1.0 stars. Further analysis are in progress. This message may be cited." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3487 SUBJECT: GRB050525A,optical observation DATE: 05/05/26 11:36:19 GMT FROM: Shouta Maeno at U.of Miyazaki S.maeno,E.sonoda,Y.Tokunaga,M.Yamauchi (University of Miyazaki) "We have observed the field covering the error circle of GRB 050525A (GCN3466 ; Swift BAT Trigger time is 00:02:53 UT) with the unfiltered CCD camera on the 30-cm telescope at University of Miyazaki. The observation was started 12:05:50 UT on May.25. After co-adding a set of 73 images (12:05:50 - 14:26:49 UT) of 30 sec exposures, we have compared with the USNO A2.0 catalog. Preliminary analysis shows there is no new source brighter than 17.7 mag at the position reported by Rykoff et al.(GCN 3468) and Torii et al.(GCN 3470) //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3488 SUBJECT: GRB 050525a: MDM Observations DATE: 05/05/26 15:35:49 GMT FROM: Nestor Mirabal at U Michigan N. Mirabal (U. Michigan), D. Bonfield and K. Schawinski (U. Oxford), report on behalf of the MDM GRB follow-up team: "Continuous r'-band photometry of the GRB 050525a afterglow (Rykoff et al. GCN #3465) was obtained with the RETROCAM imager (Morgan et al., astro-ph/0502274) installed on the MDM 2.4m telescope. The data consists of ~120 points spanning from 4.4 hr to 11.6 hr after the burst. During this period, the magnitude of the optical afterglow is seen to decline from R ~ 18.5 to R ~ 19.6, referenced to the R ~ 17.2 USNO star listed by Rykoff et al. (GCN #3465). A fit to the latter part of the observations yields a power-law decay slope of -1.38 +/- 0.2, consistent with a tentative steepening of the decay after ~0.4 days. Further analysis is in progress. A graph of the preliminary differential magnitude light curve is available at http://www-personal.umich.edu/~mirabal/grb050525/lightc.ps" //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3489 SUBJECT: GRB 050525: MITSuME Optical Observation in VRI DATE: 05/05/26 15:49:41 GMT FROM: Nobuyuki Kawai at Tokyo Tech K. Yanagisawa (OAO/NAOJ), H. Toda, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: "We observed the field of GRB 050525 (Band et al.; GCN 3466) with the 3-color MITSuME 50cm Telescope at Okayama, Japan starting at 12:03(UT) on May 25, 2005. We obtained a 5400 sec exposure (120 sec x 45 frames; midtime=13:02 UT) simultaneously in V, R, and I-bands. We confirmed the optical afterglow (Rykoff et al.; GCN 3465) in R and I bands at the position RA=18:32:32.6, DEC=+26:20:22 (J2000) with magnitudes R = 19.30 +/- 0.17 and I = 20.12 +/- 0.29. We did not detect the optical transient in the V-band image with an upper limit of V=19.2." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3490 SUBJECT: GRB 050525B: Swift-BAT observations DATE: 05/05/26 18:09:33 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift J. Cummings (GSFC/NRC), L. Barbier (GSFC), S. Barthelmy (GSFC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (UMD), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), T. Mitani (ISAS), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), M. Suzuki (Saitama), J. Tueller (GSFC), on behalf of the Swift-BAT team: From 00:49:50 to approximately 00:50:06 UT Swift-BAT recorded high rates from GRB 050525B (Mereghetti et al., GCN Circ 3477, Golenetskii et al. GCN Circ 3474). The burst was not in the BAT field of view, and was primarily detected in the high energy band (>100 keV) through the side or bottom of the instrument. Thus BAT did not find a position, and detailed information about the flux and spectrum is not available. The light curve is complex. Peaks occur at 00:49:50, 00:49:52, 00:49:55, and a complex of peaks with the most intense flux from 00:49:59 to 00:50:06. The peak rate in a 64 ms interval was recorded at 00:50:00.12. (The association of the small peak at 00:49:39, which initiated BAT trigger 130094, with the others is uncertain, because GRB 050525B was not coded by the mask and, unlike the other peaks, the trigger peak's energy profile is not obviously that of exposure through the side or bottom of the instrument.) The light curve is available at: http://swift.gsfc.nasa.gov/docs/swift/results/releases/images/GRB050525b/ We note that GRB 050525A was well below the Earth horizon from the point of view of Swift at the time of this burst, and therefore cannot be connected with this GRB 050525B event. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3491 SUBJECT: GRB 050525a: SARA Observations DATE: 05/05/26 23:42:35 GMT FROM: Autumn Homewood at Clemson U Autumn Homewood, Dieter H. Hartmann, Kiran Garimella (Clemson Univ.), Gary Henson (ETSU), Jeremy McLaughlin (Radford Univ.), Adam Brimeyer (Iowa State Univ.) report: We observed a 6x6 arcminute field centered on the optical afterglow of GRB 050525a (GCN 3466), identified by ROTSE-IIIc (GCN 3465) with the SARA 0.9 m Telescope at KPNO. Observations were carried out under good seeing conditions with the AP7 CCD. We obtained 35 300-second exposures each in the R-band, in 2 seperate groups. Observations of the first group (27 images) started at UT 2005/05/25 04:40:15, and ended 07:08:07. Observations of the second group (8 images) began at UT 10:51:29, and ended at 11:33:59. At the beginning of the first observation run we detect the afterglow at R = 18.9 +/- 0.2 mag, relative to USNO B2.0 R1. The SARA home page can be found at http://www.astro.fit.edu/sara/sara.html This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3492 SUBJECT: GRB050525a: optical upper limits DATE: 05/05/27 14:01:46 GMT FROM: Vasilij Rumjantsev at CrAO V.Rumyantsev (CrAO), G. Kornienko, A. Erofeeva, (UAPhO), A.Pozanenko (IKI) on behalf of larger GRB follow up collaboration report: We have observed the refined error box (Cummings et al., GCN 3449) of the Swift GRB050525a (Band et al., GCN 3466) with 0.4m telescope of Ussuriysk Astrophysical Observatory (UAPhO), and AT-64 telescope of CrAO on May, 25. We do not detect OT found by Rykoff et al., (GCN 3465). Upper limits of unfiltered stacked images calibrated against of R USNO-A2.0 are following: Mean time Exposure Limiting mag. May 25 (UT) (s) 13:59 7x60 15.9 19:38 40x60 19.5 The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3493 SUBJECT: GRB 050525: RTT150, Optical observations DATE: 05/05/27 15:44:50 GMT FROM: Irek Khamitov at TUG Z. Aslan, I. Khamitov, T. Ozisik, K. Uluc (TUG), U. Kiziloglu (METU), I. Bikmaev, N. Sakhibullin (KSU/AST), A. Alpar (SabUni), A.Yaskovich, R.Burenin, M. Pavlinsky, R. Sunyaev (IKI), report: We have observed the field of OT of GRB 050525 (Rykoff et al, GCN3465) with 2k*2k Andor CCD attached to the Russian-Turkish 1.5-m telescope (Bakirlitepe, Turkey) in VRc bands. We made series of 5*90s exposures in V, starting at 00:22UT May 26, and 20*60s exposures in Rc, starting at 01:18 UT May 26. On 20 co-added R-images we clearly see the OT at the position RA = 18:32:32.57 (2000.0), DEC=+26:20:22.5 (2000.0) based on the USNO-B1 catalog, its uncertainty is about 0.1 arcsec. We estimate m_R magnitude of OT using USNO-B1 as 21.76+/-0.17 corresponding to the midtime of 25.5 hours after the burst. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3495 SUBJECT: GRB050525a: Radio Observations DATE: 05/05/28 05:31:14 GMT FROM: Patrick B. Cameron at Caltech P. B. Cameron (Caltech) and D. A. Frail (NRAO) report on behalf of the Caltech-NRAO-Carnegie GRB Collaboration: "We observed the field of GRB050525a (GCN#3466) using the Very Large Array at a frequency of 22.5 GHz on May 25.42 UT and May 26.36 UT. We detect a radio source at the position of the optical transient (GCN#3468)." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3506 SUBJECT: GRB 050525a, SMARTS optical/IR afterglow observations DATE: 05/05/31 20:45:24 GMT FROM: Bethany Cobb at Yale U B. E. Cobb and C. D. Bailyn (Yale), part of the larger SMARTS consortium, report: Using the ANDICAM instrument on the 1.3m telescope at CTIO, we obtained simultaneous optical/IR imaging of the error region of GRB 050525a (Band et al. GCN 3466). Several dithered images were obtained in each filter, with total summed exposure times of 180s in each of BRIYJK and 120s in each of H and V. Imaging was carried out in a symmetrical manner so that the mid-exposure time is the same for all final combined images, in this case being ~5.2 hours post-burst (2005-05-25 05:13 UT). The afterglow reported by Rykoff et al. (GCNs 3465, 3468) is detected in each summed image, though the source appears only slightly above the background. Preliminary comparison with USNO B1.0 stars in the optical and 2MASS stars in the IR yields the following approximate afterglow magnitudes: filter AG mag ------ ------ B 18.8+/-0.4 R 18.1+/-0.3 I 18.8+/-0.3 J 17.4+/-0.3 H 16.6+/-0.3 K 16.15+/-0.35 Furthermore, a second epoch of imaging was obtained at a mid-exposure time of ~53.4 hours post-burst (2005-05-27 05:27 UT). Total summed exposure times for these images was 36 min in I and 30 min in J. The afterglow experienced significant decay between epochs and is not detectable in the second epoch images to a limiting magnitude of I > 21.2+/-0.2 and J > 18.8+/-0.1. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3507 SUBJECT: GRB 050525a, infrared observations DATE: 05/06/01 16:50:24 GMT FROM: Peter Garnavich at U of Notre Dame D. Kaplan (MIT), P. Garnavich (Notre Dame), J. Rosenberg (CfA) and K.Z. Stanek (CfA, Ohio State) The field of GRB 050525a (Band et al. GCN 3466) was imaged with the PANIC infrared camera on the Baade telescope of the Magellan Observatory on May 26 and 27 (UT) and we detect the afterglow (Rykoff et al. GCN 3465;3468) in the Ks-band on both nights. Using the 2MASS calibrated stars in the field we find the afterglow on May 26.278 (UT) to have Ks=19.2+/-0.1. We also have properly calibrated the FLWO observation obtained on May 25 (Rosenberg & Garnavich GCN 3471) and combined all three nights of data. We find that the afterglow light curve in the K-band is well represented by a power-law decay with a slope of -1.6 and Ks=18.75 one day after the burst. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3532 SUBJECT: GRB 050525a, Mid-Infrared Observations DATE: 05/06/07 22:53:44 GMT FROM: Peter Garnavich at U of Notre Dame P. Garnavich (Notre Dame), M. Pahre (CfA), A. Noriega-Crespo (CalTech), K.Z. Stanek (CfA, OSU), S.T. Holland (GSFC), D. Bersier (STScI), T. Matheson (NOAO), R. Perna (U. Colorado), K. Krisciunas (Notre Dame) After confirmation of a bright optical afterglow associated with GRB 050525 (Band et al. GCN 3466; Rykoff et al. GCN 3465;3468) we triggered a "target-of-opportunity" (ToO) program on the Spitzer Space Telescope. Observations began on May 27.26 (UT), or 2.26 days after the burst, with IRAC imaging followed by IRS spectroscopy, MIPS mapping and finally another epoch of IRAC images ending on May 27.56 (UT). Soon after triggering the ToO, the brightness of the afterglow switched to a steeper decline rate (Mirabal et al. GCN 3488; Kaplan et al. GCN 3507) making a rapid response essential. The first epoch of imaging shows point source at the position of the afterglow (Rykoff et al. GCN 3468; Yanagisawa et al. GCN 3489) in the 3.6,4.5 and 8.0 micron IRAC channels and in the 24 micron MIPS band. A second epoch of IRAC imaging and MIPS mapping was performed on May 29. The source is seen to fade in IRAC between the two epochs of the first visit and is beyond the detection limit during the second visit. The MIPS 24 micron source is also seen to fade between visits. This is the first confirmed detection of a GRB afterglow at mid-infrared wavelengths. Preliminary estimate of the flux in the IRAC channels combined with K-band observations of Kaplan et al. (GCN 3507) suggests a spectral energy distribution consistent with a power-law. The index of the power-law between 2 and 8 microns is 1.3+/-0.2. This is surprisingly steep and further analysis is continuing. The IRAC 3.6 micron images taken at two epochs can be viewed at: http://www.nd.edu/~pgarnavi/grb050525/irac.jpg We thank Nancy Silbermann and the Spitzer Science Center for rapidly responding to a complex target-of-opportunity observation. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3550 SUBJECT: GRB050525a: HST Observations DATE: 05/06/16 15:43:35 GMT FROM: Alicia Soderberg at Caltech A. M. Soderberg (Caltech) reports on behalf of the Caltech-NRAO-Carnegie collaboration: "We observed the field of GRB050525a (GCN 3466) with HST+ACS/WFC on 12 Jun 2005 UT (t~18 days) as part of our HST Cycle 13 program to study the supernovae associated with gamma-ray bursts and X-ray flashes (GO 10135; PI Kulkarni). Coincident with the afterglow position (GCN 3468), we detect a point source superposed on top of a compact galaxy. Within a 0.5 arcsec aperture, we find the host+OT system to be F625W ~ 24.2 mag (Vega). Adopting this value as a limit on the brightness of an associated supernova, we find that the SN associated with GRB050525a is at least ~0.6 magnitudes fainter than SN1998bw at a comparable epoch (assuming negligible host extinction). Further observations are planned." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3551 SUBJECT: GRB 050525A: Swift Late-Time Decay Rate DATE: 05/06/21 20:27:28 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC GRB 050525A: Swift Late-Time Decay Rate S. T. Holland, (GSFC/USRA), D. Band (GXFC), A. Blustin (MSSL), P. Boyd (GSFC/UMBC), F. Marshall (GSFC), K. Mason (MSSL), M. Perri (ASI), A. Breeveld (MSSL), P. Brown, A. Cucchiara, C. Gronwall, S. Hunsberger, M. Ivanushkina (PSU), W. Landsman (GSFC), K. McGowan (MSSL), A. Morgan (PSU), M. De Pasquale, T. Poole (MSSL), P. Roming (PSU), S. Rosen, (MSSL), P. Schady (MSSL), M. Still (GSFC/USRA), J. Nousek (PSU), N. Gehrels (GSFC), on behalf of the Swift UVOT team report: Swift/UVOT data suggest that there is a jet break at 17,979 s (0.205 d) after the BAT trigger (Band et al. 2005, GCN 3466) in the optical/ultraviolet afterglow of GRB 050525A. The observed decay index after the jet break is -1.73. The Swift/XRT data also show a late-time break followed by a steep power-law decay. If we extrapolate the UVOT late-time decay to the time of the HST F625W observation (Soderberg 2005, GCN 3550) the predicted magnitude of the optical afterglow is approximately V = 27.4. Therefore the HST observations suggest that the optical afterglow of GRB 050525A was approximately three magnitudes brighter at 18 days after the burst than expected from the fireball model alone. More data are needed to determine if this additional luminosity is due to a host galaxy or some form of rebrightening such as a supernova or a dust echo. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3566 SUBJECT: GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration DATE: 05/07/06 18:42:11 GMT FROM: Melissa Nysewander at UNC,Chapel Hill M. Nysewander (North Carolina), J. Flasher (Colorado), F. Hearty (Colorado), G. Stringfellow (Colorado), J. Walawender (Colorado), D. Q. Lamb (Chicago), J. Dembicky (APO), J. Barentine (APO), R. McMillan (APO), B. Ketzeback (APO), D. Reichart (North Carolina), and D. G. York (Chicago) report on behalf of the FUN GRB collaboration: Using griz all-sky photometry of a 4.8 arcmin x 4.8 arcminute field centered on the coordinates of the optical afterglow of GRB 0505025a that was derived from ARC 3.5-meter SPIcam observations made between 4:00 and 7:00 UT on 2005 June 13, we have calculated the griz magnitudes of 103 sources in the field of GRB 050525a: http://www.physics.unc.edu/~mnysewan/grb050525a.dat The astrometry in these files is based on the USNO B1.0-catalogue. The estimated systematic errors in the astrometry are less than 400mas. The estimated systematic photometric errors are typically ± 0.05 mag in the gri bands and ± 0.06 mag in the z band. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3567 SUBJECT: GRB 050525a: ARC 3.5-meter Optical and NIR Observations DATE: 05/07/06 19:00:54 GMT FROM: Don Lamb at U.Chicago GRB 050525a: ARC 3.5-meter Optical and NIR Observations J. Flasher (Colorado), F. Hearty (Colorado), G. Stringfellow (Colorado), J. Walawender (Colorado), D. Q. Lamb (Chicago), D. G. York (Chicago), G. Wallerstein (Washington), V. Woolf (Washington), S. Anderson (Washington), J. Dembicky (APO), J. Barentine (APO), R. McMillan (APO), and B. Ketzeback (APO) report on behalf of the ARC GRB team of the FUN GRB collaboration: We observed the afterglow (Rykoff et al., GCN Circular No. 3465; Malesani et al., GCN Circular No. 3469) of GRB 050525a, a burst localized by Swift/BAT (Band et al., GCN Circular No. 3466; Markwardt et al., GCN Circular No. 3467), on the night of May 24th, using SPIcam and NIC-FPS on the ARC 3.5-meter telescope at Apache Point Observatory. The observation began at 08.33 UT on 25 May 2005 (8.28 hours after the burst) and ended at 11.07 UT on 25 May 2005 (11.02 hours after the burst). The observation consisted of two 300-second exposures each in r, i, and z; and a series of 60-, 60-, 10-, and 10-second exposures in Z, J, H, and Ks, respectively. We have constructed stacked images of the GRB field, corresponding to 10-minute integrations in r, i, z, and Z; and 20-minute integrations in J, H, and Ks. We detect the afterglow in all seven filters, and measure J = 18.3 ± 0.1 at 09:50 UT (the mid-point time of the J-band observation), calibrated relative to the 2MASS stars in the field. NIC-FPS is currently in its commissioning phase. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3568 SUBJECT: GRB 050525a: PROMPT VRcIc Detections DATE: 05/07/06 19:25:10 GMT FROM: Josh Haislip at U.North Carolina J. Haislip, C. MacLeod, M. Nysewander, A. Foster, J. A. Crain, D. Reichart, M. Bayliss, J. Kirschbrown, and C. Mack report on behalf of the UNC team of the FUN GRB Collaboration: We observed the BAT localization of GRB 050525a (Band et al., GCN 3466) with PROMPT-5 beginning 5.3 hours after the burst. We detect the afterglow (Rykoff et al., GCN 3465) in VRcIc across multiple epochs. Using the field calibration of Nysewander et al. (GCN 3566), we find that Rc =3D 19.84 +/- 0.11 mag at a mean time of 8.1 hours after the burst. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3566 SUBJECT: GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration DATE: 05/07/06 18:42:11 GMT FROM: Melissa Nysewander at UNC,Chapel Hill M. Nysewander (North Carolina), J. Flasher (Colorado), F. Hearty (Colorado), G. Stringfellow (Colorado), J. Walawender (Colorado), D. Q. Lamb (Chicago), J. Dembicky (APO), J. Barentine (APO), R. McMillan (APO), B. Ketzeback (APO), D. Reichart (North Carolina), and D. G. York (Chicago) report on behalf of the FUN GRB collaboration: Using griz all-sky photometry of a 4.8 arcmin x 4.8 arcminute field centered on the coordinates of the optical afterglow of GRB 0505025a that was derived from ARC 3.5-meter SPIcam observations made between 4:00 and 7:00 UT on 2005 June 13, we have calculated the griz magnitudes of 103 sources in the field of GRB 050525a: http://www.physics.unc.edu/~mnysewan/grb050525a.dat The astrometry in these files is based on the USNO B1.0-catalogue. The estimated systematic errors in the astrometry are less than 400mas. The estimated systematic photometric errors are typically ± 0.05 mag in the gri bands and ± 0.06 mag in the z band. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3567 SUBJECT: GRB 050525a: ARC 3.5-meter Optical and NIR Observations DATE: 05/07/06 19:00:54 GMT FROM: Don Lamb at U.Chicago GRB 050525a: ARC 3.5-meter Optical and NIR Observations J. Flasher (Colorado), F. Hearty (Colorado), G. Stringfellow (Colorado), J. Walawender (Colorado), D. Q. Lamb (Chicago), D. G. York (Chicago), G. Wallerstein (Washington), V. Woolf (Washington), S. Anderson (Washington), J. Dembicky (APO), J. Barentine (APO), R. McMillan (APO), and B. Ketzeback (APO) report on behalf of the ARC GRB team of the FUN GRB collaboration: We observed the afterglow (Rykoff et al., GCN Circular No. 3465; Malesani et al., GCN Circular No. 3469) of GRB 050525a, a burst localized by Swift/BAT (Band et al., GCN Circular No. 3466; Markwardt et al., GCN Circular No. 3467), on the night of May 24th, using SPIcam and NIC-FPS on the ARC 3.5-meter telescope at Apache Point Observatory. The observation began at 08.33 UT on 25 May 2005 (8.28 hours after the burst) and ended at 11.07 UT on 25 May 2005 (11.02 hours after the burst). The observation consisted of two 300-second exposures each in r, i, and z; and a series of 60-, 60-, 10-, and 10-second exposures in Z, J, H, and Ks, respectively. We have constructed stacked images of the GRB field, corresponding to 10-minute integrations in r, i, z, and Z; and 20-minute integrations in J, H, and Ks. We detect the afterglow in all seven filters, and measure J = 18.3 ± 0.1 at 09:50 UT (the mid-point time of the J-band observation), calibrated relative to the 2MASS stars in the field. NIC-FPS is currently in its commissioning phase. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3568 SUBJECT: GRB 050525a: PROMPT VRcIc Detections DATE: 05/07/06 19:25:10 GMT FROM: Josh Haislip at U.North Carolina J. Haislip, C. MacLeod, M. Nysewander, A. Foster, J. A. Crain, D. Reichart, M. Bayliss, J. Kirschbrown, and C. Mack report on behalf of the UNC team of the FUN GRB Collaboration: We observed the BAT localization of GRB 050525a (Band et al., GCN 3466) with PROMPT-5 beginning 5.3 hours after the burst. We detect the afterglow (Rykoff et al., GCN 3465) in VRcIc across multiple epochs. Using the field calibration of Nysewander et al. (GCN 3566), we find that Rc = 19.84 +/- 0.11 mag at a mean time of 8.1 hours after the burst. PROMPT is still being built and commissioned. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3660 SUBJECT: Correction to GCN Circ 3474 on GRB050525A DATE: 05/07/21 14:58:14 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and T. Cline on behalf of the Konus-Wind team report: In GCN 3474 we reported wrong value of the Konus-Wind fluence for GRB 050525A (because of missprinting). The correct value is (2.06 +/- 0.02)10-5 erg/cm2 . The reported peak flux and spectral parameters were correct. We thank Dr. Hurley for noticing this error. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3721 SUBJECT: Correction to GCN Circ 3476 on GRB050525A DATE: 05/08/01 14:46:46 GMT FROM: Jean-Luc Atteia at Lab d Astrophys.,OMP,Toulouse J-L. Atteia & A. Pelangeon (LAT-OMP) report: Taking into account the revised value of the fluence of GRB 050525a provided by Golenetskii et al. in GCN 3660, we have re-computed the pseudo-redshift of GRB 050525a (using the method described in Atteia, 2003, A&A, 407, L1). We find a pseudo-redshift pz=0.64 +/- 0.1, in good agreement with the spectroscopic redshift z=0.606 //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3855 SUBJECT: GRB050525, GRB050607, GRB050802 BVRcIc field photometry DATE: 05/08/22 15:26:26 GMT FROM: Arne A. Henden at AAVSO A. Henden (AAVSO/USNO) reports on behalf of the USNO GRB Team: We have acquired BVRcIc all-sky photometry for 23x23arcmin fields centered on the coordinates of recent GRB localizations with the USNOFS 1.0-m telescope on 1 or 2 photometric nights but with bright moonlight and variable seeing. Stars brighter than V=12.0 are saturated and should be used with care. We have placed the photometric data on our anonymous ftp site: ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb050525.dat ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb050607.dat ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb050802.dat The astrometry in these files is based on linear plate solutions with respect to UCAC2 or USNO-A2.0. The external errors are usually 200mas or better. The estimated external photometric error is about 0.03mag. Some fields are relatively crowded, and the large apertures required to handle the variable seeing also blended some measurements, so choose comparison stars wisely. We have one additional night for GRB050525 that will be added when reductions are complete. As always, you should check the dates on the .dat file prior to final publication to get the latest photometry. There is a README file on the ftp directory to give you information about the procedures used to calibrate these fields.