//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7512 SUBJECT: GRB 080325: Swift detection of a burst DATE: 08/03/25 04:25:22 GMT FROM: David Palmer at LANL L. Vetere (PSU), P. J. Brown (PSU), D. Grupe (PSU), C. B. Markwardt (CRESST/GSFC/UMD), C. Pagani (PSU), D. M. Palmer (LANL), J. L. Racusin (PSU), M. C. Stroh (PSU) and T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team: At 04:09:17 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 080325 (trigger=307604). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 277.895, +36.511 which is RA(J2000) = 18h 31m 35s Dec(J2000) = +36d 30' 38" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Because this is a 64-sec long image trigger, the TDRSS lightcurve does not show any significant signal (as is typical). The XRT began observing the field at 04:11:49.2 UT, 151.9 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 277.8920, +36.5221 which is equivalent to: RA(J2000) = 18h 31m 34.0s Dec(J2000) = +36d 31' 19.5" with an uncertainty of 4.7 arcseconds (radius, 90% containment). This location is 40 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to assess possible redshift constraints using X-ray spectroscopy and the nH-z relation from Grupe et al. (2007). UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 162 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. Image catalog data are not available at this time. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.06. Burst Advocate for this burst is L. Vetere (vetere AT astro.psu.edu). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7513 SUBJECT: GRB 080325: Enhanced Swift-XRT position DATE: 08/03/25 11:21:05 GMT FROM: Phil Evans at U of Leicester J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team. Using 199 s of overlapping XRT Photon Counting mode and UVOT data for GRB 080325, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 277.89272, +36.52381 which is equivalent to: RA (J2000): 18h 31m 34.25s Dec (J2000): +36d 31' 25.7" with an uncertainty of 2.6 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401 http://www.swift.ac.uk/xrt_positions/Goad.pdf), the current algorithm is an extension of this method. This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7515 SUBJECT: GRB 080325: NIR afterglow candidate DATE: 08/03/25 15:43:08 GMT FROM: Adria C. Updike at Clemson U Adria C. Updike, Brian C. Donehew, Ian Oliver, and Dieter H. Hartmann (Clemson University) report: We imaged the field of GRB 080325 (Vetere et al., GCN 7512) with the KPNO 2.1m + FLAMINGOS in the J band beginning 5 hours and 42 minutes after the trigger. Within the enhanced XRT position (Osborne et al., GCN 7513), we detect a source at RA = 18:31:34.185, Dec = +36:31:19.60 (+/- 2 arcseconds). Days after trigger Band Magnitude -------------------------------------------------- 0.23775 J 18.76 +/- 0.14 0.25022 J 18.85 +/- 0.13 0.26427 J 19.42 +/- 0.26 Magnitudes are derived relative to the 2MASS catalog. This sequence suggests a fading source. Further observations are required to confirm this detection. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7516 SUBJECT: GRB 080325: Early observations from OSN DATE: 08/03/25 18:33:39 GMT FROM: Antonio Deugarte at IAA-CSIC A. de Ugarte Postigo (ESO, Chile), A. Sota, J.Gorosabel, A.J. Castro-Tirado (IAA-CSIC) report, We have observed the field of GRB 080325 (Vetere et al. GCN 7512) with the 1.5m OSN telescope at Sierra Nevada Observatory (Granada, Spain) starting at 04:23:01 UT, 12.48 minutes after the burst. Inside the initial XRT error box there is an object with coordinates R.A.: 18:31:34.13 Dec.: +36:31:19.8 (J2000 +/- 0.5"), which is also present in the DSS, consistent with the coordinates reported by Updike et al. (GCN 7515). Inside the refined XRT error box (Osborne et al. GCN 7513) we do not detect any new source down to the following 3-sigma limits (t-t0 being the mean observing time since the GRB): (t-t0) (min) | Exp. time (s) | I-band limit 12.65 | 20 | > 19.5 14.36 | 9x20 | > 20.8 39.46 | 2300s | > 21.8 This message may be cited //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7518 SUBJECT: GRB 080325: Swift/UVOT Upper Limits DATE: 08/03/25 20:25:03 GMT FROM: Peter Brown at PSU P. J. Brown and L. Vetere (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 080325 (trigger=307604) starting 163 s after the BAT trigger (Vetere et al., GCN Circ. 7512). We do not detect an optical/uv afterglow at the enhanced XRT position (Osborne et al., GCN Circ. 7513), or NIR candidate (Updike et al., GCN Circ. 7515) in the initial finding chart observations or subsequent summed images down to the following 3 sigma upper limits: Filter T_start (s) T_stop Exposure MagLimit white 163 262 98 >20.6 white 163 5905 392 >21.5 v 269 513 240 >19.3 v 269 6297 419 >19.6 b 5501 5700 197 >20.6 u 4131 22211 353 >20.9 uvw1 3925 21975 2371 >21.8 uvm2 3720 10211 891 >21.1 uvw2 5912 6111 197 >20.1 The above magnitudes are not corrected for the Galactic extinction corresponding to a reddening of E(B-V) = 0 .064 mag (Schlegel et al.,1998, ApJS, 500, 525). The photometry is on the UVOT flight systemdescribed in Poole et al. (2008, MNRAS, 383,627). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7520 SUBJECT: GRB 080325: GROND Observations DATE: 08/03/25 22:56:25 GMT FROM: Christian Clemens at MPE C. Clemens, A. Kupcu Yoldas, J. Greiner, A. Yoldas, T. Kruehler and G. Szokoly (Eoetvoes Univ., Budapest and MPE Garching) (all others MPE Garching) report on behalf of the GROND team: We observed the field of GRB 080325 (Swift trigger 307604; L. Vetere et al., GCN #7512) simultaneously in g', r', i', z', J, H and K with GROND (Greiner et al. 2008, PASP) mounted at the 2.2m ESO/MPI telescope at La Silla Observatory (Chile). Observations started at 09:50 UT on March 25th, 2008, about 5.7 hrs after the GRB trigger. We obtained 20 mins of total integration time in J, H and K during morning twilight. We do not detect any new source within the 2.6'' enhanced Swift-XRT error circle reported by J. Osborne et al. (GCN #7513) to the following 3-sigma upper limits: J > 20.4, H > 19.4 and K > 19.0. We also detect the afterglow candidate, about 6" south of the centre of the enhanced Swift-XRT error circle, reported by A. Updike et al. (GCN #7515) to following magnitude: J = 18.60 +/- 0.06, calibrated against 2MASS catalogue stars. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7521 SUBJECT: GRB080325: XRT Refined Analysis DATE: 08/03/25 23:24:28 GMT FROM: Loredana Vetere at PSU L. Vetere, J. L. Racusin (PSU) report on behalf of the Swift-XRT team: We have analysed the first 8 orbits of Swift-XRT data obtained for BAT GRB 080325 (trigger 307604, Vetere et al., GCN Circ. 7512). The data consist of 360 s in Windowed Timing (WT) mode, starting 160 s after the BAT trigger and 7.8 ks in Photon Counting (PC) mode. The astrometrically corrected X-ray position is given in Osborne et al. GCN 7513. The early WT light-curve shows flaring activity followed by a fast decay that can be fit by a power law with a slope of alpha1=5.7 ± 0.5. The following PC light curve starts at 3.6 ks after BAT trigger and shows a much slower decay with a slope of alpha2=0.8 ± 0.2. If the light-curve continues to decay at the same rate, we predict an XRT count rate of 0.011 count/s at T+24 hours. The spectrum formed from all the WT data can be modeled with a power-law of photon index Gamma = 2.4 ± 0.1, with an absorbing column of NH = (3.0 ± 0.1)e21 cm^-2, significantly in excess with respect to the Galactic value of 3.81e20 cm^-2. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7522 SUBJECT: GRB 080325: MITSuME Akeno optical upper limits DATE: 08/03/26 07:40:25 GMT FROM: Nobuyuki Kawai at Tokyo Tech Y. Kudou, T. Shimokawabe and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the error box of GRB 080325 (L. Vetere et al. GCN 7512) with the 3-color 50cm MITSuME Telescope at Akeno, Japan starting at 16:51:16 Mar 25 UT, 12.7 hr after the trigger under a poor sky condition at a low altitude. In the co-added images of Ic, Rc, and g' bands, we did not detect any afterglow candidate in the XRT error circle. The 3-sigma limiting magnitudes based on USNO-B1.0 (I-band) and NOMAD (R-band,g'-band) stars are following. Filter start time end time Exposure Mag (3-sigma upper limit) ----------------------------------------------------------------- g' 16:51:16 17:54:41 15 x 60 s 17.2 Rc 16:51:16 17:54:41 15 x 60 s 16.4 Ic 16:51:16 17:54:41 15 x 60 s 17.0 ----------------------------------------------------------------- //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7524 SUBJECT: GRB 080325: Subaru detection of NIR afterglow candidate DATE: 08/03/27 06:50:55 GMT FROM: Nobuyuki Kawai at Tokyo Tech I. Tanaka, T.-S. Pyo, T. Hattori, K. Aoki (Subaru, NAOJ), C. Tokoku, T. Yamada (Tohoku U), K. Ohta (Kyoto U), and N. Kawai (Tokyo Tech) report on behalf of the Subaru GRB team: We observed the field of GRB 080325 (Vetere et al., GCN 7512) with MOIRCS on the Subaru Telescope in J and Ks bands starting at 12:51 UT, March 25, about 8.7 hours after the trigger. The observation lasted until 15:43 UT with effective exposures of 18 min in J band and 80 min in Ks band. We detected a faint extended object (Ks=19.5) in the enhanced Swift XRT error circle (Osborne et al., GCN 7513). We measure the coordinates of its center as: 18:31:34.24 +36:31:24.3 (J2000, uncertainty 0".3). There seemed to be a bright spot at the north end of this object. We performed another set of observation with MOIRCS at March 26.5-26.7 in Ks and J bands. We confirmed that the north spot of the source had faded significantly, and the total magnitude of the source had faded by 0.5 mag. Based on the positional coincidence and the fading behavior, we suggest that the faint extended source is the host galaxy of GRB 080325, and the spot in the north was the afterglow. The source 6" south of the enhanced Swift-XRT error circle reported by Updike et al. (GCN 7515) was also present in our image, and we measure its magnitude at ~14:00 UT, March 25 (10 hours after the trigger) as: J = 18.62 +/- 0.03, consistent with the magnitude reported by Clemens et al. (GCN 7520). Thus it is not likely to be the afterglow of the GRB. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7529 SUBJECT: GRB080325 - I and z-band Imaging DATE: 08/03/28 15:27:18 GMT FROM: Myungshin Im at Seoul Nat U M. Im, I. Lee (Seoul National Univ), and Y. Urata (Saitama U/ASIAA) on behalf of EAFON team. We took a series of I-band and z-band images of GRB080325, using the 1.0m telescope at Mt. Lemmon (Arizona, US) operated by the Korea Astronomy Space Science Institute. The z-band observation started at March 27, 08:46:06 UT (2.19223 days after the burst) and the I-band observation started at March 27, 10:41:05 UT (2.27208 days after the burst). We do not find an optical counterpart at the location of the NIR afterglow candidate reported by Tanaka et al. (GCN 7524), in both I and z-band stacked images. We set the limit of the GRB afterglow as I > 21.2 mag (3-sigma), calibrated with a USNO-B star at (18:31:36.3, 36:31:51.0). The afterglow candidate reported by Updike et al. (GCN 7515) is detected at both I- and z-bands, with the I-band magnitude of I=19.0 +- 0.1 mag, calibrated with the same star as above. However, we note that this object is also visible in the DSS image (POSS-II), and therefore it is unlikely to be a GRB afterglow. We thank the LOAO operator, I. Baek for her assistance for this observation. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7531 SUBJECT: GRB 080325, Swift-BAT refined analysis DATE: 08/03/28 18:08:58 GMT FROM: Craig Markwardt at NASA/GSFC/UMD E. Fenimore (LANL), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU), (i.e. the Swift-BAT team), and L. Vetere (PSU): Using the data set from T-323 to T+963 sec from all of the telemetry, we report further analysis of BAT GRB 080325 (trigger #307604) (Vetere, et al., GCN Circ. 7512). The BAT ground-calculated position is RA, Dec = 277.906, 36.516 deg which is RA(J2000) = 18h 31m 37.5s Dec(J2000) = +36d 30' 57.9" with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 10%. The mask weighted light curve has a broad FRED-like structure, with a rise to peak within ~20 sec, followed by a gradual decay extending out to T+200 sec. The low partial coding in the initial part of the burst makes it difficult to distinguish between statistical and real fluctuations. T90 (15-350 keV) is 128.4 +- 34.2 sec (estimated error including systematics). The time-averaged spectrum from T-29.3 to T+170.5 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.68 +- 0.17. The fluence in the 15-150 keV band is 4.9 +- 0.4 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+38.02 sec in the 15-150 keV band is 1.4 +- 0.6 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/307604/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7563 SUBJECT: GRB 080325: optical upper limit DATE: 08/04/04 15:16:08 GMT FROM: Graziella Pizzichini at IASF/CNR,Bologna F. Munz (INAF/IASF Bologna) F. Terra (Second University of Rome "Tor Vergata"), G. Greco, C. Bartolini, A. Guarnieri, A. Piccioni (Bologna University), G. Pizzichini (INAF/IASF Bologna), D. Nanni (INAF/OAR and Second University of Rome "Tor Vergata"), M. Redfern (National University of Ireland, Galway), A. De Blasi (Bologna Observatory) report: We observed the field of GRB 080325 (GCN 7512, Vetere et al.) with the 152 cm telescope located in Loiano. We obtained one 10 min exposure in the Rc filter at mean time 2008 March 26 0.55 UT. Further observations were prevented by clouds and the moon. We do not detect any object in the Swift-XRT error box reported by Osborne et al. (GCN 7513). Our 3-sigma limiting magnitude is R~20.6 (based on Nomad1 catalogue). The image shall be posted in our public directory from where it can be retrieved by sftp using hostname: ermione.bo.astro.it username: publicGRB password: GRB_bo directory: GRB080325