//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7800 SUBJECT: GRB 080604: Swift detection of a burst with an optical afterglow DATE: 08/06/04 07:38:24 GMT FROM: David Palmer at LANL V. La Parola (INAF-IASFPA), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), C. Guidorzi (INAF-OAB), S. T. Holland (CRESST/USRA/GSFC), N. P. M. Kuin (MSSL), J. Mao (INAF-OAB), P. T. O'Brien (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), D. Perez (U Leicester), B. Sbarufatti (INAF-IASFPA), R. L. C. Starling (U Leicester), D. E. Vanden Berk (PSU) and H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team: At 07:27:01 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 080604 (trigger=313116). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 236.970, +20.555 which is RA(J2000) = 15h 47m 53s Dec(J2000) = +20d 33' 19" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a broad single peak structure with a duration of about 70 sec. The peak count rate was ~300 counts/sec (15-350 keV), at ~10 sec after the trigger. The XRT began observing the field at 07:29:00.4 UT, 119.3 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 236.9648, +20.5572 which is equivalent to: RA(J2000) = 15h 47m 51.5s Dec(J2000) = +20d 33' 25.9" with an uncertainty of 5.4 arcseconds (radius, 90% containment). This location is 19 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy. UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 128 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 15:47:51.70 = 236.9654 DEC(J2000) = +20:33:28.1 = 20.5578 with a 1-sigma error radius of about 0.5 arc sec. This position is 3.4 arc sec. from the center of the XRT error circle. The estimated magnitude is 20.1 with a 1-sigma error of about 0.5 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.05. Burst Advocate for this burst is V. La Parola (laparola AT ifc.inaf.it). 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: 7801 SUBJECT: GRB080604: confirmation of optical afterglow DATE: 08/06/04 08:04:00 GMT FROM: Evert Rol at U.Leicester E. Rol (U. Leicester), C. Guidorzi (INAF-OAB), A. Gomboc (U. Ljubljana), I.A. Steele (Liverpool JMU), P. O'Brien (U. Leicester), A, Melandri, D. Bersier, C.G. Mundell, R.J. Smith, D. Carter, S. Kobayashi, M. Burgdorf, M. Bode (Liverpool JMU), N. Bannister, N. Tanvir (U. Leicester) report: The Faulkes Telescope North observed the position of GRB080604. We confirm the detection of an optical transient (La Parola, GCN 7800), with a position of (J2000): RA = 15 47 51.65 Dec = +20 33 28.1 In the first 10 second exposure, starting 5:42 minutes after the BAT trigger, we estimate a magnitude of R = 20.12 +/- 0.15 with respect to the USNO-B1.0 star at 15:47:52.50, +20:34:24.4. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7802 SUBJECT: GRB 080604: Early Super-LOTIS Observations DATE: 08/06/04 09:32:05 GMT FROM: Grant Williams at Steward Observatory G. G. Williams (MMTO), P. A. Milne (Steward Observatory) and A. Updike (Clemson) on behalf of the Super-LOTIS Collaboration, report: The robotic 0.6-m Super-LOTIS telescope began observing the error box of GRB 080604 (Swift Trigger 313116, La Parola et al. GCN 7800) at 07:28:59.0 UT, 118 seconds after the trigger. Our initial observations include 5 x 10s exposures, 5 x 20s exposures, and 30 x 60s exposures, all in the R-band. We do not detect the afterglow reported by La Parola et al. (GCN 7800) and confirmed by Rol et al. (GCN 7801) in our earliest exposure to the following 5-sigma limiting magnitude determined using the nearby USNO-B1.0 star 1105-0256520 at RA=15:47:45.32, Dec=+20:33:38.4 with R2mag=14.56: t_start (UT) exp t (s) t_start-t_0 (s) Limit -------------------------------------------------------- 07:28:59.0 10 118.0 R > 17.5 We also do not detect the afterglow in our later images or the sum of our 20s images and 6x60s images. Additional observations and analysis are ongoing. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7805 SUBJECT: GRB 080604: Hobby-Eberly Telescope spectroscopy DATE: 08/06/04 11:39:53 GMT FROM: Antonino Cucchiara at PSU A. Cucchiara and D. B. Fox (Penn State) report: "Starting on 2008 June 4.35 UT we used the Marcario LRS spectrograph on the Hobby-Eberly Telescope (R ~ 230) to obtain a 1200s spectrum of the optical afterglow of GRB 080604 (La Parola et al., GCN 7800). The spectrum covers the wavelength range 4500 to 10,000 Angstrom. Based on a preliminary calibration we detect absorption features corresponding to the MgII doublet (2796, 2803 A) and MgI (2852 A) as well as other metal absorption features at redshift z = 1.28. The absence of Lyman break in our dataset suggests z < 2.7. A refined analysis will be posted. We thank the HET staff for performing this observation, in particular Matthew Shetrone." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7807 SUBJECT: GRB 080604: Enhanced Swift-XRT position DATE: 08/06/04 13:01:16 GMT FROM: Phil Evans at U of Leicester P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team. Using 749 s of overlapping XRT Photon Counting mode and UVOT data for GRB 080604, 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 = 236.96516, +20.55777 which is equivalent to: RA (J2000): 15h 47m 51.64s Dec (J2000): +20d 33' 28.0" with an uncertainty of 1.7 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: 7816 SUBJECT: GRB 080604: Swift-XRT refined analysis DATE: 08/06/04 17:55:28 GMT FROM: Valentina La Parola at INAF-IASPA V. La Parola, B. Sbarufatti, V. Mangano (INAF-IASF Pa) report on behalf of the Swift-XRT team The Swift-XRT observed GRB 080604 (trigger 313116, La Parola et al. GCN Circ 7800) for 6.3 ksec, starting 119.3 seconds after the BAT trigger. We detect an X-ray counterpart at the position (astrometrically corrected using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 236.96516, +20.55777 which is equivalent to: RA (J2000): 15h 47m 51.64s Dec (J2000): +20d 33' 28.0" with an uncertainty of 1.7 arcsec (radius, 90% confidence). The X-ray light curve shows a power law decay with slope -2.18 +/-0.06, with a hint of a flare at ~T+1000 s. The spectrum accumulated over the whole observation can be modelled with an absorbed powerlaw with the following parameters (Galactic nH is 4.0e20cm**-2): nH = (8 +/- 4)e20 cm**-2 Gamma= 1.8 +/- 0.2 Flux (0.3-10 keV) 4.18E-12 ergs cm**-2 s**-1 Unabsorbed Flux (0.3-10 keV) = 4.9E-12 ergs cm**-2 s**-1 The predicted XRT count rate after 24 hours from the burst is 1.5e-5 counts/s This circular is an official product of the Swift-XRT team. I.A.S.F. INAF Mailing System Outgoing mail is certified Virus Free. Checked by McAfee anti-virus system //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7817 SUBJECT: GRB 080604, Swift-BAT refined analysis DATE: 08/06/04 18:03:17 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), V. La Parola (INAF-IASFPA), C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD), D. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from recent telemetry downlinks, we report further analysis of BAT GRB 080604 (trigger #313116) (La Parola, et al., GCN Circ. 7800). The BAT ground-calculated position is RA, Dec = 236.960, 20.557 deg, which is RA(J2000) = 15h 47m 50.3s Dec(J2000) = +20d 33' 25.4" with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows a single peak starting at ~T-25 sec and ending at ~T+100 sec. T90 (15-350 keV) is 82 +- 13 sec (estimated error including systematics). The time-averaged spectrum from T-27.3 to T+67.2 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.78 +- 0.18. The fluence in the 15-150 keV band is 8.0 +- 0.9 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T-3.02 sec in the 15-150 keV band is 0.4 +- 0.1 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/313116/BA/ This burst satisfies Sakamoto/Ukwatta Swift-BAT possible high-z criteria (Ukwatta et al. arXiv:0802.3815): 1) Pawer Law photon index = 1.78 (PL photon index < 2) 2) 1-s peak photon flux = 0.4 (1-s peak photon flux < 1.0 ph/cm2/s) 3) Light curve variance = 1.1e-05 (Variance < 0.0001) 4) T90/(Peak photon flux) = 218 (T90/(Peak photon flux) > 100) Based on a limited sample of bursts, these criteria yield an 85% chance it has a redshift greater than 3.5. We note that the Cucchiara (GCN Circ 7805) HET spectrum yields a z = 1.28. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7818 SUBJECT: GRB 080604: Gemini-North spectroscopy DATE: 08/06/04 20:46:50 GMT FROM: Klaas Wiersema at U of Leicester K. Wiersema (U. of Leicester), J. Graham (STScI), N. Tanvir, E. Rol (U. of Leicester), A. Levan (U. of Warwick) and A. Fruchter (STScI) report on behalf of a larger collaboration: We observed the optical afterglow of GRB 080604 (GCNC 7800, 7801) with Gemini-North, using the GMOS-N instrument. Spectroscopy was performed with the R400 grism, using 4 x 450 seconds integration time, starting at 2008 June 04, 08:58 UT. Several absorption lines of, among others, Fe II (2382,2586,2600), Mg II (2796,2803) and Mg I (2026,2852) are found at a redshift of 1.416. The discrepancy with respect to the redshift reported in GCN 7805 may be due to provisional calibration files used for the HET reduction (Cucchiara priv. comm.). We thank the Gemini staff astronomers for their support in obtaining these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7819 SUBJECT: GRB080604: HET redshift retraction DATE: 08/06/04 20:56:18 GMT FROM: Antonino Cucchiara at PSU A. Cucchiara and D. B. Fox (Penn State) report: Based on updated calibration files we re-analyzed the GRB080604 spectrum taken at HET (GCN 7805). The features reported in the previous GCN are no longer significant at a 3-sigma confidence level. Furthermore, only an upper limit of z < 2.8 can be derived from our dataset. Our revised results are consistent with the results from Gemini-North spectroscopy (Wiersama et al., GCN 7818). The low signal to noise of our spectrum does not permit detection of the absorption features associated with the z=1.416 system seen in those data. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7820 SUBJECT: Swift/UVOT observations of GRB080604 DATE: 08/06/04 21:27:12 GMT FROM: Massimiliano de Pasquale at MSSL-UCL M. De Pasquale (MSSL/UCL), V. La Parola (INAF-IASFPA), F. E. Marshall (GSFC) report: The Swift UltraViolet/Optical Telescope (UVOT) began its first finding chart exposure of GRB080604 (La Parola et al., GCN circ. 7800) 129 seconds after the trigger in white filter and detected the optical afterglow (GCN circ. 7800). The coordinates of this transient are: Dec: 15:47:51.68 RA: +20:33:28.0 The afterglow is detected only in the white filter. Magnitudes and 3 sigma upper limits are listed in the table below. Filter T_start(s) T_stop(s) Exp(s) Magnitude white 129 228 99 20.1 +/- 0.2 white 730 739 10 > 19.7 white 869 968 99 21.0 +0.3 -0.2 white 1479 1651 39 > 20.7 white 5369 7031 393 21.8 +0.5 -0.4 v 235 635 393 > 20.1 v 769 1373 412 > 20.0 v 1519 1701 39 > 18.8 v 5807 7441 393 > 19.9 v 17489 18395 885 > 20.3 b 716 725 10 > 19.0 b 1454 1637 39 > 19.8 b 5191 6826 393 > 21.0 u 691 862 39 > 19.4 u 1430 1612 39 > 19.4 u 4896 6621 393 > 20.7 u 12600 13306 689 > 21.0 uw1 667 1738 46 > 19.6 uw1 6217 12591 1082 > 21.2 um2 641 19090 1931 > 21.6 uw2 745 17482 1395 > 21.4 The values quoted above are on the UVOT Photometric System (Poole et al, 2008, MNRAS 383,627). They are not corrected for the expected Galactic reddening of E(B-V) = 0.049 in the direction of the burst (Schlegel et al. 1998). _______________________________________________ Uvot_cal mailing list Uvot_cal@phoenix.astro.psu.edu https://phoenix.astro.psu.edu/mailman/listinfo/uvot_cal //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7821 SUBJECT: GRB 080604: MITSuME Okayama observation DATE: 08/06/05 10:00:56 GMT FROM: Michitoshi Yoshida at Okayama Astrophysical Obs M. Yoshida, K. Yanagisawa, D. Kuroda, Y. Shimizu, S. Nagayama, H. Toda (OAO, NAOJ) and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the field of GRB 080604 (La Parola et al., GCN7800) with the 50cm MITSuME Telescope at Okayama Astrophysical Observatory on June 4 UT. We detected a faint point source at the UVOT position (La Parola et al., GCN7800; Rol et al., GCN7801; De Pasquale et al., GCN7820) in our Ic band image. Photometric calibration was done using USNO-B1.0 catalog. mid-UT exp-T g' Rc Ic ------------------------------------------------------------ 2008-6-4 12:41:48 49min >20.0 >19.2 18.6 +/- 0.4 ------------------------------------------------------------ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7825 SUBJECT: GRB 080604: Xinglong R band observation DATE: 08/06/05 16:25:28 GMT FROM: W.K. Zheng at NAOC X.M. Meng, Y.N. Zhu, L.P. Xin, Q.C. Feng, M. Zhai, Y.L. Qiu, J.Y. Wei, J.Y. Hu, J.S. Deng, J. Wang, Y. Urata and W.K. Zheng on behalf of EAFON report: We observed GRB080604 (La Parola et al., GCN 7800) with Xinglong 2.16m telescope + BFOSC on Jun 4, 8.024 hours after the burst. We marginally detected the OT (La Parola et al., GCN 7800; Rol et al., GCN 7801; De Pasquale et al., GCN 7820) at 3 sigma level. The estimated brightness was R ~ 21.6 +/- 0.3 calibrated to USNO-A2.0 stars. This message may be cited. For more information about Xinglong GRBs Follow-up observations, please visit the website: http://www.xinglong-naoc.org/grb/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7842 SUBJECT: GRB 080604: VLA radio upper limit DATE: 08/06/06 17:49:20 GMT FROM: Poonam Chandra at U Virginia/NRAO Poonam Chandra (NRAO/UVA) and Dale A. Frail (NRAO) report on behalf of the Caltech-NRAO-Carnegie GRB Collaboration: "We used the Very Large Array to observe the field of view toward GRB 080604 (GCN 7800) at a frequency of 8.46 GHz on 2008 June 05.22 UT. The GRB radio afterglow is undetected and the peak radio flux at the SWIFT-UVOT position (GCN 7800) is -8 ± 39 uJy. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc."