GRB080605A

This page lists all entries on GRB080605A in GRBweb

Summary IPN Swift GCN 7828 GCN 7829 GCN 7830 GCN 7831 GCN 7832 GCN 7833 GCN 7834 GCN 7835 GCN 7836 GCN 7837 GCN 7838 GCN 7839 GCN 7841 GCN 7844 GCN 7845 GCN 7851 GCN 7854 GCN 7857 GCN 7863 GCN 7864

Summary table
Variable Value Source
T0 23:47:57 UTC GCN_circulars,Swift Det
ra 262.1252° Swift
decl 4.0155° Swift
pos_error 6.47e-05° Swift
T90 20.0 s Swift
T90_start 23:47:57 UTC Swift
fluence 1.33e-05 erg/cm² Swift
redshift 1.6398 GCN_circulars,Optical
T100 20.0 s
GBM_located False
mjd 54622.991631944446 GCN_circulars,Swift Det
IPN table
GRB_name GRB080605A
ra 262.1292°
decl 4.0000°
pos_error 5.00e-02°
redshift 1.6398
Swift table
GRB_name GRB080605A
t_trigger 23:47:57 UTC
ra 262.1252°
decl 4.0155°
pos_error 6.47e-05°
T90 20.0 s
fluence 1.33e-05 erg/cm²
redshift 1.6398
GCN 7828 table
GRB_name GRB080605A
GCN_number 7828
Detection_method Swift Det
t_trigger 23:47:57 UTC
ra 262.1270°
decl 4.0020°
Circular_text TITLE: GCN CIRCULAR NUMBER: 7828 SUBJECT: GRB 080605: Swift detection of a burst with an optical afterglow DATE: 08/06/06 00:13:48 GMT FROM: David Palmer at LANL B. Sbarufatti (INAF-IASFPA), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), S. T. Holland (CRESST/USRA/GSFC), V. La Parola (INAF-IASFPA), V. Mangano (INAF-IASFPA), C. B. Markwardt (CRESST/GSFC/UMD), D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (NASA/UMBC), T. N. Ukwatta (GSFC/GWU) and D. E. Vanden Berk (PSU) report on behalf of the Swift Team: At 23:47:57 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 080605 (trigger=313299). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 262.127, +4.002 which is RA(J2000) = 17h 28m 31s Dec(J2000) = +04d 00' 06" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows multiple overlapping peaks lasting at least to T+8 sec (at which the TDRSS lightcurve is truncated). The peak count rate was ~17000 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began observing the field at 23:49:28.2 UT, 90.4 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 262.1249, +4.0153 which is equivalent to: RA(J2000) = 17h 28m 29.9s Dec(J2000) = +04d 00' 55.0" with an uncertainty of 5.0 arcseconds (radius, 90% containment). This location is 48 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. The UVOT detects a new source within the XRT error circle. We are unable to obtain a position or magnitude at this time. The source is very close to a known source in the DSS. Further information will be provided when it is available. Burst Advocate for this burst is B. Sbarufatti (sbarufatti 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.)
GCN 7829 table
GRB_name GRB080605A
GCN_number 7829
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 7829 SUBJECT: GRB 080605: TLS RRM Afterglow DATE: 08/06/06 00:17:51 GMT FROM: Alexander Kann at TLS Tautenburg This is a multi-part message in MIME format. --bound1212711210 Content-Type: text/plain Content-Transfer-Encoding: 7bit D. A. Kann, U. Laux, S. Klose, S. Ertel (TLS Tautenburg) and J. Greiner (Garching) report: We observed the location of Swift GRB 080605 with the TLS Tautenburg 1.34m Schmidt telescope in RRM Mode (Klose et al., GCN 3609). At the in-flight XRT position, in a 120 sec Ic band frame, we detect a new source not present in the DSS at: RA (J2000) = 17:28:29.96 Dec. (J2000) = +04:00:57.5 The source is blended with a star to the southeast but clearly discernible. We propose this to be the afterglow of GRB 080605. Spectroscopy is encouraged. This message may be cited. --bound1212711210--
GCN 7830 table
GRB_name GRB080605A
GCN_number 7830
Detection_method Swift-UVOT Other
ra 262.1253°
decl 4.0156°
Circular_text TITLE: GCN CIRCULAR NUMBER: 7830 SUBJECT: GRB 080605: Swift/UVOT Position of the Optical Afterglow DATE: 08/06/06 00:27:40 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/USRA/GSFC) and B. Sbarufatti (INAF-IASFPA) report on behalf of the Swift Team: Swift/UVOT began observing the field of GRB 080605 (Sbarufatti et al. 2008, GCN Circ. 7828) with a 99 s white exposure starting 104 s after the BAT trigger. The preliminary Swift/UVOT position of the optical afterglow candidate is RA(J2000) = 17:28:30.07 Dec(J2000) = +04:00:56.0 with an estimated position uncertainty of 1.0 arcsec. There is a known source (USNO-B1.0 940-028965) 3 arcsec from this position.
GCN 7831 table
GRB_name GRB080605A
GCN_number 7831
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 7831 SUBJECT: GRB 080605: Liverpool Telescope optical afterglow candidate DATE: 08/06/06 00:40:18 GMT FROM: Andreja Gomboc at LT,ARI,Liverpool JMU A. Gomboc (U. Ljubljana), A. Melandri, R.J. Smith, C.G. Mundell, I.A. Steele, D. Bersier, S. Kobayashi, D. Carter, M. Burgdorf, M.F. Bode (Liverpool JMU), C. Guidorzi (INAF-OAB) report: The Liverpool Telescope (La Palma) automatically reacted to the Swift trigger 313299 and started observing the field 3 min after the trigger. We find an un-catalogues source at RA 17:28:29.9, dec +04:00:55.0 consistent with the XRT position. The magnitude of the source is R=18.3 at 11.3 min after the trigger.
GCN 7832 table
GRB_name GRB080605A
GCN_number 7832
Detection_method Optical
redshift 1.6398
Circular_text TITLE: GCN CIRCULAR NUMBER: 7832 SUBJECT: GRB 080605: VLT redshift DATE: 08/06/06 03:56:15 GMT FROM: Pall Jakobsson at U Hertfordshire Pall Jakobsson (U. Hertfordshire), Paul M. Vreeswijk, Dong Xu and Christina C. Thoene (DARK, NBI) report on behalf of a larger collaboration: Using FORS2 on the Very Large Telescope, we have obtained a 10 min spectrum (grism 300V) of the optical afterglow of GRB 080605 (Sbarufatti et al., GCN 7828). The acquisition image shows it to have R = 20.4 on June 6.063 (1.7 hours post burst). A firm upper limit of z < 2.1 can be placed on the redshift of GRB 080605 from the lack of Ly-alpha forest lines in the spectrum of the afterglow. The spectrum is rich in absorption features, including Si II, C IV, Al II, Al III, Zn II, Fe II, Mg II and Mg I, corresponding to a redshift of z = 1.6398 +/- 0.0006. We thank the Paranal staff for excellent support, especially Linda Schmidtobreick.
GCN 7833 table
GRB_name GRB080605A
GCN_number 7833
Detection_method Optical
ra 17.0000°
decl 4.0000°
Circular_text TITLE: GCN CIRCULAR NUMBER: 7833 SUBJECT: GRB080605: optical observations DATE: 08/06/06 04:22:14 GMT FROM: Alexei Pozanenko at IKI, Moscow V. Rumyantsev (CrAO), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the optical afterglow (Kann, et al., GCN 7829; Holland et al., GCN 7830; Gomboc et al., GCN 7831) of Swift GRB 080605 (Sbarufatti et al., GCN 7828) in R and I bands on June 05 Zeiss-1000 (Simeiz) telescope of CrAO observatory under not optimal weather conditions. Based on USNO-B1.0 star RA (J2000) = 17 28 29.92, Dec. (J2000) = +04 00 36.5, R2=15.90 we estimated brightness of the optical afterglow in first frames: UT, Exposure, R_mag, (start time) 2008-06-05T23:55:58 120 s 17.9 2008-06-06T00:00:34 120 s 18.4 During observations the afterglow is clearly faded. Coordinates of the afterglow with uncertainties of 0.3": RA(2000): 17 28 30.01 Dec(2000): +04 00 56.4 A finding chart can be found at http://grb.rssi.ru/GRB080605/grb080605_080605_z1000.gif The message may be cited.
GCN 7834 table
GRB_name GRB080605A
GCN_number 7834
Detection_method Optical
ra 262.1252°
decl 4.0156°
Circular_text TITLE: GCN CIRCULAR NUMBER: 7834 SUBJECT: GRB 080605: GROND detection of the optical afterglow candidate DATE: 08/06/06 04:30:38 GMT FROM: Christian Clemens at MPE C. Clemens, T. Kruehler, J. Greiner, A. Kupcu Yoldas, A. Yoldas (all MPE Garching) and G. Szokoly (Eoetvoes Univ., Budapest and MPE Garching) report on behalf of the GROND team: We observed the field of GRB 080605 (Swift trigger 313299; Sbarufatti et al., GCN #7828) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m ESO/MPI telescope at La Silla Observatory (Chile). Observations started at 01:10:59 UT on June 6th, 2008, 83 mins after the GRB trigger, and are continuing. We found a single and relatively bright point source within the 1.0'' Swift-UVOT error circle reported by Holland et al. (GCN #7830) at RA (J2000) = 17h 28m 30.05s DEC (J2000) = +04d 00' 56.2" with a typical uncertainty of 0.8", which is consistent with the sources reported by Kann et al. (GCN #7829) and Gomboc et al. (GCN #7831). Based on 460 s and 1500 s of effective exposures taken 1.65 hrs and 2.78 hrs after the trigger, we estimate preliminary magnitudes of r' = 20.3 and i' = 19.4, as well as r' = 20.7 and i' = 19.9 with typical errors of +/- 0.1. (Given magnitudes are calibrated against USNO-B1 field stars and might be affected by the bright, nearby star.) This indicates a clear fading of the source, which we therefore suggest to be the optical afterglow of GRB 080605.
GCN 7835 table
GRB_name GRB080605A
GCN_number 7835
Detection_method Swift-XRT Det
ra 262.1253°
decl 4.0161°
Circular_text TITLE: GCN CIRCULAR NUMBER: 7835 SUBJECT: GRB 080605: Enhanced Swift-XRT position DATE: 08/06/06 11:41:27 GMT FROM: Phil Evans at U of Leicester M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team. Using 426 s of overlapping XRT Photon Counting mode and UVOT data for GRB 080605, 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 = 262.12533, +4.01608 which is equivalent to: RA (J2000): 17h 28m 30.08s Dec (J2000): +04d 00' 57.9" with an uncertainty of 1.8 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.
GCN 7836 table
GRB_name GRB080605A
GCN_number 7836
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 7836 SUBJECT: GRB 080605: MASTER VWF 46 s AT observation DATE: 08/06/06 11:52:33 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs MASTER-Net Team: D.Kuvshinov, V. Lipunov, V.Kornilov, E.Gorbovskoy, A.Belinski, N.Shatskiy, N.Tyurina, Sternberg Astronomical Institute, Moscow Union 'Optic' A. Tlatov, I.Golubov Kislovodsk Solar Station of the Pulkovo observatory V.Krushinski, I.Zalognikh Ural State University, Kourovka S.Yazev, K.Ivanov Irkutsk State University MASTER Very Wide Field Camera located at Kislovodsk Solar Station (http://observ.pereplet.ru, D=50 mm, 1015 square degrees, 35'' per pix) has moved to the Swift-BAT trigger 313299 (23:47:57 UT) and it has taken a series of 5s exposures starting 46s after the GRB time and 12 s after notice arrivel time at 23:48:43 UT under good weather condition, but large zenit distance. These unfiltered images are calibrated relative to USNO A2.0 (R). There is no OT was found inside Swift error box (B. Sbarufatti, S. D. Barthelmy et al., GCN Circ 7828). T-Tgrb Mean Time Limit Coadd? Note 46s 48.5s >9.0 no moving 51s 53.5s >10.0 no 51s 56.0s >10.2 2 51s 76.0s >11.0 10 51s 101.0s >11.5 20 The message can be cited. mailto: lipunov@sai.msu.ru PS. AT = After Trigger
GCN 7837 table
GRB_name GRB080605A
GCN_number 7837
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 7837 SUBJECT: GRB080605: observation by BOOTES DATE: 08/06/06 12:36:57 GMT FROM: Martin Jelinek at Inst.Astrophys.Andalucia,Granada M. Jelinek, A.J.Castro-Tirado, J. Gorosabel (IAA CSIC Granada), Petr Kubanek (GACE Valencia), S. Vitek (FEL CVUT Praha), A. de Ugarte Postigo (ESO Santiago), on behalf of a larger Collaboration: report: "We observed the optical afterglow of GRB 080605 (Kann et al. GCN 7829, Sbarufatti et al. GCN 7828, Gomboc et al. GCN 7831) with the 30cm BOOTES-1B and with the 60cm BOOTES-2/TELMA robotic telescopes in southern Spain. The sequence of observations started 43s after the GRB trigger. We clearly detect a 15th mag transient outshining the nearby star in R-band (BOOTES-2/TELMA) and without filter (BOOTES-1B). "
GCN 7838 table
GRB_name GRB080605A
GCN_number 7838
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 7838 SUBJECT: GRB 080605: Swift-XRT refined analysis DATE: 08/06/06 17:22:59 GMT FROM: Boris Sbarufatti at INAF-IASF-Pa B. Sbarufatti, V. Mangano, V. La Parola (INAF-IASF Pa) report on behalf of the Swift-XRT team The XRT began observations of GRB 080605 (trigger=313299, Sbarufatti et al., GCN circ. 7828) started on 2008 May 05 at 23:49:36 UT, 97 s after the BAT trigger. The data consist of 642 s in Windowed Timing mode and 4.3 ks s in Photon Counting mode. The light curve is described by a powerlaw with initial slope 0.65 (+/-0.05) until T+ 280s (+90, - 45), at which point the decay steepens to an index 1.32 (+/-0.03). The spectrum of the WT mode data can be fitted by a powerlaw with photon index 1.78 (+/- 0.04) and an intrinsic absorbing column of 6.6 (+/-0.9)E21 cm^-2 at z=1.6398 (Jakobsson et al., GCN circ. 7832), in excess over the Galactic value of 6.67E20 cm^-2. The observed (unabsorbed) flux is 7.5 (8.1)E-10 erg cm^-2 s^-1. The first orbit PC mode spectrum (379 s of exposure) can be fit by a powerlaw with photon index 1.6 (+/- 0.2) and an intrinsic absorbing column of 4.8 (+/-4)E21 cm^-2. The observed (unabsorbed) flux is 3.0 (3.3)E-10 erg cm^-2 s^-1. The countrate to flux conversion factor is 4.87e-11 erg cm^-2 s^-1. The predicted countrate 24 h after the trigger is 1.6E-2 counts/s, equivalent to an observed flux of 7.8E-13 erg cm^-2 cts^-1. This circular is an official product of the Swift-XRT team.
GCN 7839 table
GRB_name GRB080605A
GCN_number 7839
Detection_method Swift-BAT Det
ra 262.1300°
decl 4.0100°
Circular_text TITLE: GCN CIRCULAR NUMBER: 7839 SUBJECT: GRB 080605, Swift-BAT refined analysis DATE: 08/06/06 17:37:12 GMT FROM: Scott Barthelmy at NASA/GSFC J. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC), E. Fenimore (LANL), 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 (ISAS), M. Stamatikos (GSFC/ORAU), B. Sbarufatti (INAF-IASFPA), J. Tueller (GSFC), T. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-240 to T+962 sec from recent telemetry downlinks, we report further analysis of BAT GRB 080605 (trigger #313299) (Sbarufatti, et al., GCN Circ. 7828). The BAT ground-calculated position is RA, Dec = 262.130, 4.010 deg, which is RA(J2000) = 17h 28m 31.1s Dec(J2000) = +04d 00' 35.6" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 41%. The mask-weighted light curve shows a cluster of overlapping peaks starting at ~T-3 sec, the largest peak at ~T+8 sec, and all ending at ~T+70 sec. At the 1-2 sigma level, there is appears to be persistant emmission in the T+300 to T+700 sec range. T90 (15-350 keV) is 20 +- 1 sec (estimated error including systematics). The time-averaged spectrum from T-5.5 to T+30.0 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.11 +- 0.14, and Epeak of 223 +- 133 keV (chi squared 28.10 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 1.33 +- 0.02 x 10^-5 erg/cm2 and the 1-sec peak flux measured from T+7.57 sec in the 15-150 keV band is 19.9 +- 0.6 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.36 +- 0.03 (chi squared 37 for 57 d.o.f.). 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/313299/BA/
GCN 7841 table
GRB_name GRB080605A
GCN_number 7841
Detection_method Swift-BAT Det
ra 262.1300°
decl 4.0100°
Circular_text TITLE: GCN CIRCULAR NUMBER: 7841 SUBJECT: GRB 080605, Swift-BAT refined analysis DATE: 08/06/06 17:44:56 GMT FROM: Scott Barthelmy at NASA/GSFC J. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC), E. Fenimore (LANL), 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 (ISAS), M. Stamatikos (GSFC/ORAU), B. Sbarufatti (INAF-IASFPA), J. Tueller (GSFC), T. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-240 to T+962 sec from recent telemetry downlinks, we report further analysis of BAT GRB 080605 (trigger #313299) (Sbarufatti, et al., GCN Circ. 7828). The BAT ground-calculated position is RA, Dec = 262.130, 4.010 deg, which is RA(J2000) = 17h 28m 31.1s Dec(J2000) = +04d 00' 35.6" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 41%. The mask-weighted light curve shows a cluster of overlapping peaks starting at ~T-3 sec, the largest peak at ~T+8 sec, and all ending at ~T+70 sec. At the 1-2 sigma level, there is appears to be persistant emmission in the T+300 to T+700 sec range. T90 (15-350 keV) is 20 +- 1 sec (estimated error including systematics). The time-averaged spectrum from T-5.5 to T+30.0 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.11 +- 0.14, and Epeak of 223 +- 133 keV (chi squared 28.10 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 1.33 +- 0.02 x 10^-5 erg/cm2 and the 1-sec peak flux measured from T+7.57 sec in the 15-150 keV band is 19.9 +- 0.6 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.36 +- 0.03 (chi squared 37 for 57 d.o.f.). 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/313299/BA/
GCN 7844 table
GRB_name GRB080605A
GCN_number 7844
Detection_method Swift-UVOT Other
ra 262.1252°
decl 4.0156°
Circular_text TITLE: GCN CIRCULAR NUMBER: 7844 SUBJECT: GRB 080605: Swift-UVOT refined analysis DATE: 08/06/06 20:45:57 GMT FROM: Paul Kuin at MSSL N. P. M. Kuin (MSSL/UCL), B. Sbarufatti (INAF-IASFPA), F. Marshall (GSFC), and P.Schady (MSSL/UCL), report on behalf of the Swift UVOT team The Swift UltraViolet/Optical Telescope (UVOT) began observations of GRB 080605, on June 5, 2008, at 23:49:19 UT, 82 seconds after the initial Swift BAT trigger (Mangano et al., GCN Circ. 7794), and started the finding chart exposure in the white filter at 102 seconds after the trigger. The refined uvot position of GRB080605 is RA=262.12522, Dec=+4.01555 deg.(= 17:28:30.05 +04:00:55.97), with an accuracy of 0.5", consistent with the positions reported in GCN Circ. 7830 (Holland et al.) and 7835 (Goad et al.). The GRB is found close (about 4" distant) to a star, which may cause an error in the measured flux, especially at later times. For this analysis we use a small 2" aperture which which reduces the contamination, and apply a standard aperture correction. We note that the DSS image indicates the presence of a weak, possibly extended source near the position of the afterglow. The magnitudes with 1-sigma errors for GRB080605 are given below for the initial observation sequence. Filter Tstart(s) Tstop(s) Exp(s) Magnitude wh 102 201 98.2 18.11 +/- 0.06 v 208 607 393.5 18.53 +/- 0.11 wh 858 957 98.2 20.02 +/- 0.17 uvm2 615 788 38.9 >18.38 (3 sigma UL) uvw1 639 813 38.9 >18.95 (3 sigma UL) uvw2 720 739 19.5 >18.16 (3 sigma UL) b 27679 28264 571.7 21.10 +/- 0.27 u 18432 41856 550.7 21.17 +/- 0.43 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) = 0.137 in the direction of the burst (Schlegel et al. 1998).
GCN 7845 table
GRB_name GRB080605A
GCN_number 7845
Detection_method correction
Circular_text TITLE: GCN CIRCULAR NUMBER: 7845 SUBJECT: GRB 080605: TLS RRM Analysis, Plateau/Rebrightening, Red OT DATE: 08/06/07 02:27:14 GMT FROM: Alexander Kann at TLS Tautenburg D. A. Kann, U. Laux and S. Ertel (TLS Tautenburg) report: We continue observations of the afterglow of GRB 080605 (independently discovered by Sbarufatti et al., GCN 7828, Kann et al., GCN 7829, and Gomboc et al., GCN 7831). We acquired one 300 sec image each in V, R, and I around 0.95 days after the GRB, and further imaging 0.1 days later until dawn. Astonishingly, the afterglow is still clearly visible in R and I bands. As mentioned in the above-cited GCNs, the afterglow is close to a star and affected by its PSF in images with low-quality seeing or large pixel scale, such as the TLS camera. To obtain a qualitative description of the afterglow evolution, we perform aperature photometry in a 3 pixel aperature, and derive the aperature correction for each image by comparing the counts for a reference star in the 3 pixel aperature with that in a 7 pixel (which is typically seeing-matched) aperature. As a reference star, we use the star to the south of the afterglow, USNOB1.0 ID 0940-0289655 at (catalog position): RA = 17:28:29.920, Dec. = +04:00:36.51, which has R2 = 15.90 mag, I = 14.54 mag. We derive the following magnitudes for selected images in the I band (the error is estimated to be 0.1 magnitudes in all cases): dt I 0.00478791 16.74 0.00674681 17.18 0.00869923 17.36 0.01064872 17.61 0.01849396 18.19 0.02433042 18.19 0.05922051 18.48 0.96109933 18.51 1.05275325 18.71 The early afterglow decay (0.00479 to 0.01849 days) is well-described by a power-law with decay slope alpha=0.97. After this, the afterglow decay seems to flatten. Between 0.06 days and 0.95 days, the afterglow magnitude remains unchanged, indicating a plateau phase. As the afterglow has resumed its decay 0.1 days later, this probably implies that the afterglow underwent a strong rebrightening which we caught after the peak. This is reminiscent of GRB 071003, which lies at a very similar redshift (Perley et al. 2008, ApJ, submitted, arXiv:0805.2394) of ~ 1.6 (Jakobsson et al., GCN 7832). Furthermore, we determined the R band magnitude at two epochs: dt R 0.01655957 19.87 0.95457023 20.75 Corrected for the moderate Galactic foreground extinction of E(B-V) = 0.136, we find R - I ~ 2 mag. This is a very red color for an afterglow, indicating strong internal reddening due to dust. We caution that the USNOB1.0 comparison star may have incorrect photometry, on the other hand, a simple image comparison shows that the R band magnitude is much fainter than the I band magnitude. The strong rebrightening combined with the large correction for dust extinction that is needed imply that this is an intrinsically extremely luminous afterglow. Further follow-up, especially in the NIR bands, is highly encouraged. This message may be cited.
GCN 7851 table
GRB_name GRB080605A
GCN_number 7851
Detection_method correction
Circular_text TITLE: GCN CIRCULAR NUMBER: 7851 SUBJECT: GRB 080605: GROND 2nd epoch observations DATE: 08/06/07 09:44:28 GMT FROM: Christian Clemens at MPE C. Clemens, A. Kupcu Yoldas, J. Greiner, T. Kruehler, A. Yoldas (all MPE Garching) and G. Szokoly (Eoetvoes Univ., Budapest and MPE Garching) report on behalf of the GROND team: We observed the field of GRB 080605 for a second time at 02:43 UT on June 7th, 2008 about 1.12 days after the GRB trigger with 25 mins of effective exposures in g'r'i'z'. We still detect the bright afterglow within the refined 0.5'' Swift-UVOT error circle (Kuin et al., GCN #7844) to the following preliminary magnitudes of r' = 22.3, i' = 21.7 and z' = 21.4 with typical errors of +/- 0.1. Given magnitudes are calibrated against USNO-B1 field stars and might be affected by the bright, nearby star. This indicates a clear fading of the optical afterglow compared to our first epoch observations (C. Clemens et al., GCN #7834). Please note, that no correction for the galactic foreground reddening of E(B-V) = 0.136 mag (Schlegel et al., 1998) has been applied.
GCN 7854 table
GRB_name GRB080605A
GCN_number 7854
Detection_method Konus-Wind Det
t_trigger 23:48:02.336 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 7854 SUBJECT: Konus-Wind observation of GRB 080605 DATE: 08/06/07 16:02:39 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: The bright GRB 080605 (Swift-BAT trigger #313299: Sbarufatti et al., GCN 7828, Cummings et al., GCN 7839) triggered Konus-Wind at T0=85682.336 s UT (23:48:02.336). The burst light curve shows a multipeaked structure with a total duration of ~20s. As observed by Konus-Wind the burst had a fluence of 3.02(-0.12, +0.13)x10^-5 erg/cm2, and a 16-ms peak flux measured from T0+7.984 s of (1.60 +/- 0.33)x10^-5 erg/cm2/s (both in the 20 keV - 2 MeV energy range). The time-integrated spectrum of the burst (from T0 to T0+18.944 s) can be fitted (in the 20 keV - 2 MeV range) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.03 +/- 0.07, and Ep = 252(-17, +20) keV (chi2 = 57.2/61 dof). Fitting by GRBM (Band) model yields: the low-energy photon index is alpha = -1.02 +/- 0.08, the high energy photon index beta < -2.75, the peak energy Ep = 246(-18, +23) keV (chi2 = 56.7/60 dof). The spectrum of the most intense peak (from T0+7.168 s to T0+8.960 s) is well fitted (in the 20 keV - 2 MeV range) by a power law with exponential cutoff model with alpha = -0.94 +/- 0.10 and Ep = 333(-34, +42) keV (chi2 = 60.6/54 dof). Fitting by GRBM (Band) model yields: the low-energy photon index is alpha = -0.87(-0.12, +0.13), the high energy photon index beta = -2.58(-0.84, +0.31), the peak energy Ep = 297(-40, +46) keV (chi2 = 56.6/53 dof). All the quoted errors are at the 90% confidence level. Assuming z = 1.640 (Jakobsson et al., GCN 7832) and a standard cosmology model with H_0 = 70 km/s/Mpc, Omega_M = 0.27, Omega_\Lambda = 0.73, the isotropic energy release is E_iso ~2.1x10^53 erg, the maximum luminosity is (L_iso)_max ~3.0x10^53 erg/s, and Ep_rest ~660 keV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.rssi.ru/LEA/GRBs/GRB080605_T85682/
GCN 7857 table
GRB_name GRB080605A
GCN_number 7857
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 7857 SUBJECT: GRB 080605: optical observations DATE: 08/06/07 19:42:52 GMT FROM: Alexei Pozanenko at IKI, Moscow V. Rumyantsev (CrAO), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the optical afterglow of Swift GRB 080605 (Sbarufatti et al., GCN 7828) in second epoch on June 06 with Zeiss-1000 (Simeiz) telescope of CrAO observatory with favorable weather conditions and seeing about 2". Our first epoch astrometry of the source (Rumyantsev et al., GCN 7833) is in agreement with refined UVOT position of GRB080605 (Kuin et al., GCN 7844). The observation of the first epoch started 8 minute after burst onset (Rumyantsev et al., GCN 7833) was performed under descending weather conditions with seeing about 3". Improved photometry of the first epoch observation as well as observation on June 6 is based on USNO-B1.0 star RA (J2000) = 17 28 29.92, Dec.(J2000) = +04 00 36.5, assuming R=15.90, I=14.54: T0+ Exposure, Filter, mag, (d,mid time) 0.006251 120 R 18.04 +/- 0.08 0.007698 120 R 18.43 +/- 0.06 0.009457 120 R 18.62 +/- 0.06 0.010985 120 R 18.63 +/- 0.23 0.015163 120 R 18.93 +/- 0.23 0.018068 120 R >19.04 0.019504 120 R 18.86 +/- 0.20 0.026031 120 I 18.12 +/- 0.28 0.033219 120 V >17.50 0.034654 120 V >18.20 0.904028 34x120 R 21.13 +/- 0.06 The photometry is still preliminary and not corrected for Galaxy extinction and might be affected by the bright, nearby star. It is evident that the source is faded between June 5 and June 6. Power law index of early afterglow decay ~0.8 is compatible with index obtained in I-band (Kann et al., GCN 7845). However our absolute photometry in R-band have a significant offset in comparison with early observations by Kann et al. (GCN 7845) and compatible with photometry of Gomboc et al. (GCN 7831). Our early observation suggests R-I ~ 1.2, however we caution the color of the afterglow is also depending on photometry which is affected by bright, nearby star. The message may be cited.
GCN 7863 table
GRB_name GRB080605A
GCN_number 7863
Detection_method MITSuME
Circular_text TITLE: GCN CIRCULAR NUMBER: 7863 SUBJECT: GRB080605: optical observation with the MITSuME-OAO telescope DATE: 08/06/09 00:24:33 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 performed optical imaging observation (Rc, and Ic) of the field of GRB 080605 (Sbarufatti et al., GCN 7828) with 50cm MITSuME telescope at Okayama Astrophysical Observatory June 6 2008 UT. We detected a point source at the UVOT position of the optical afterglow (Kuin et al., GCN 7844). Differential photometry was made using a USNO B1.0 star, USNO-ID 0940-0289655 (Kann et al., GCN 7845). The Ic-band magnitude of the source was almost constant from T-T0 = 0.516 to 0.756. The source is about 1.5 magnitude fainter in Rc-band than in Ic-band. These results are consistent with other reports (Kann et al., GCN 7845, Rumyantsev et al., GCN 7857). MITSuME observation start: 2008-06-06 11:35:11 UT mid-UT T-T0(days) exp-T Ic (2008-06-06) --------------------------------------------------- 12:11:27 0.516314 60 min 19.03 +/- 0.38 12:48:05 0.541753 60 min 19.00 +/- 0.29 14:00:54 0.592315 60 min 18.85 +/- 0.18 15:15:44 0.644288 60 min 19.03 +/- 0.22 16:30:50 0.696429 60 min 18.82 +/- 0.21 17:56:24 0.755856 80 min 18.87 +/- 0.30 --------------------------------------------------- mid-UT (2008-06-06) T-T0(days) ext-T Rc --------------------------------------------------- 15:52:20 0.669745 120 min 20.58 +/- 0.32 ---------------------------------------------------
GCN 7864 table
GRB_name GRB080605A
GCN_number 7864
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 7864 SUBJECT: GRB 080605: TLS 3rd Epoch - Source Confusion DATE: 08/06/09 01:24:01 GMT FROM: Alexander Kann at TLS Tautenburg D. A. Kann, U. Laux & S. Ertel (TLS Tautenburg) report: We obtained further images of the Swift GRB 080605 (Sbarufatti et al., GCN 7828). A 300 second Ic frame obtained under excellent observing conditions shows the field remains unchanged in comparison to the second epoch as well as the final images of the first epoch (Kann et al., GCN 7845). Recently, Yoshida et al. (GCN 7863) also claimed detection of a plateau phase. Clemens et al. (GCN 7851), on the other hand, report a clear fading of the afterglow, as well as only a moderately red color in comparison to Kann et al. (GCN 7845), which can possibly be explained by the moderate Galactic reddening alone. Comparison with a multicolor finding chart taken by GROND (C. Clemens, priv. comm.) reveals the culprit: source confusion. Near the position of the afterglow, there are in total three sources, all seemingly stellar in GROND images, along a line. The star to the southeast (Source #1) was immediately reported (Sbarufatti et al., GCN 7828, Kann et al., GCN 7829) and is clearly visible in the DSS. To the northwest, there is another source (Source #2), also clearly visible in the DSS. An inspection of the DSS IR frame reveals that #2 is hardly visible at all, but a new source (Source #3), inbetween #1 and #2, now becomes clearly visible. This source is extremely red, possibly a red dwarf, and it is THIS source which begins to dominate the photometry reported in Kann et al. (GCN 7845) (and presumably Yoshida et al., GCN 7863), which is mostly I band. The small offset from source #1 lead us to believe that this is the afterglow (and explained the puzzling observation that it seemed to slightly shift position). Therefore, we retract the identification of a plateau phase of the afterglow of GRB 080605, as well as the claim of extreme redness and the resulting high lumonisity around 1 day in the observer frame. On the other hand, the afterglow IS clearly detected on the early I band frames of the TLS RRM observation, as well as in the R band and a stacked V band frame. The early photometry, which leads to a decay slope of alpha ~ 1, is still valid. Image subtraction will have to be performed to see how many detections we have actually gotten. This message may be cited.