//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9086 SUBJECT: GRB 090404: Swift detection of a burst DATE: 09/04/04 16:07:58 GMT FROM: Scott Barthelmy at NASA/GSFC H. Ziaeepour (UCL-MSSL), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester), S. R. Oates (UCL-MSSL), K. L. Page (U Leicester), D. M. Palmer (LANL) and B. Sbarufatti (INAF-IASFPA) report on behalf of the Swift Team: At 15:56:30 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 090404 (trigger=348428). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 239.218, +35.500 which is RA(J2000) = 15h 56m 52s Dec(J2000) = +35d 29' 59" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multiply-peaked structure with a duration of about 80 sec and possible activity out to T+100 sec. The peak count rate was ~3500 counts/sec (15-350 keV), at ~17 sec after the trigger. The XRT began observing the field at 15:57:57.8 UT, 87.3 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 239.2351, +35.5173 which is equivalent to: RA(J2000) = 15h 56m 56.42s Dec(J2000) = +35d 31' 02.2" with an uncertainty of 5.0 arcseconds (radius, 90% containment). This location is 79 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 150 seconds with the White filter starting 96 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 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 0.02. Burst Advocate for this burst is H. Ziaeepour (hz AT mssl.ucl.ac.uk). 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: 9088 SUBJECT: GRB 090404: Enhanced Swift-XRT position DATE: 09/04/04 21:31:18 GMT FROM: Phil Evans at U of Leicester A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team. Using 989 s of XRT Photon Counting mode data and 2 UVOT images for GRB 090404, 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 = 239.23986, +35.51615 which is equivalent to: RA (J2000): 15h 56m 57.57s Dec (J2000): +35d 30' 58.1" 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) and Evans et al. (2009, arXiv:0812.3662). This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9089 SUBJECT: GRB 090404: Swift-BAT refined analysis DATE: 09/04/04 23:48:55 GMT FROM: Scott Barthelmy at NASA/GSFC J. Tueller (GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), T. N. Ukwatta (GWU), H. Ziaeepour (UCL-MSSL) (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 090404 (trigger #348428) (Ziaeepour, et al., GCN Circ. 9086). The BAT ground-calculated position is RA, Dec = 239.233, 35.518 deg, which is RA(J2000) = 15h 56m 55.8s Dec(J2000) = +35d 31' 03.4" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 89%. The mask-weighted light curve shows at least 7 overlapping peaks starting at ~T-50 sec and ending at ~T+150 sec. T90 (15-350 keV) is 84 +- 14 sec (estimated error including systematics). The time-averaged spectrum from T-35.2 to T+94.6 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.32 +- 0.08. The fluence in the 15-150 keV band is 3.0 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+17.32 sec in the 15-150 keV band is 1.9 +- 0.2 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/348428/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9090 SUBJECT: GRB 090404: Xinglong TNT optical Upper Limit DATE: 09/04/04 23:49:27 GMT FROM: L.P. Xin at NAOC GRB 090404: Xinglong TNT optical Upper Limit L.P. Xin, W.K. Zheng, Y.L. Qiu, J.Y. Wei, j. Wang, J.S. Deng, Y. Urata and J.Y. Hu on behalf of EAFON report: We have observed GRB090404 (Ziaeepour et al., GCN 9086; Beardmore et al., GCN 9088) with Xinglong TNT telescope from Apr.4,15:58:17 (UT), 107 sec after the burst. After combined 18*20s white band images, no new source was found in our combined image. The 3 sigma upper limits calibrated to USNO-B1.0 R2 magnitude is R=20.37 mag at the mean time of 333 sec after the trigger. 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: 9091 SUBJECT: GRB 090404: Swift-XRT Team refined analysis DATE: 09/04/05 00:01:05 GMT FROM: Kim Page at U.of Leicester K.L. Page (U. Leicester) & H. Ziaeepour (UCL-MSSL) report on behalf of the Swift-XRT team: We have analysed the first 3 orbits of XRT data obtained for GRB 090404 (Ziaeepour et al. 2009, GCN Circ. 9086), comprising 129 s in Windowed Timing mode and 5.4 ks in Photon Counting (PC) mode. The UVOT-enhanced position was given by Beardmore et al. (GCN Circ. 9088). The X-ray afterglow was initially very bright, starting at a count rate of ~1200 count s^-1. The light-curve can be approximately modelled with a doubley broken power-law: alpha1 = 3.2 +/- 0.3 until around 120 s after the burst, at which point the decay steepened to a slope of alpha2 = 9.3 +/- 0.3. After 265 s, the decay is much more gradual, with alpha3 = 0.17 +/- 0.06. The data show significant softening until at least 150 s after the trigger. A spectrum extracted from the first orbit of PC data can be fitted with a power-law of Gamma = 3.0 +/- 0.5 and a total absorbing column of 5.1x10^21 cm^-2, which is in excess of the Galactic value of 2.0x10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.1x10^-11 (1.4x10^-10) erg cm^-2 count^-1. If the light-curve continues to decay with alpha ~ 0.17, the predicted count rate at 24 hours is 0.14 count s^-1, corresponding to an observed (unabsorbed) flux of 4.3x10^-12 (2.0x10^-11) erg cm^-2 s^-1. However, we note that it is unlikely that the light-curve decay will still be this flat at 24 hours. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00348428. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9092 SUBJECT: GRB 090404: optical observations at BOOTES-3 and 1.5-m OSN DATE: 09/04/05 00:34:01 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia P. Yock (Auckland Univ.), B. Allen (Vintage Lane Obs., Blenheim), , A. de Ugarte Postigo (ESO Santiago), P. Kubánek (GACE, Univ. of Valencia), A. Sota and A. J. Castro-Tirado (IAA-CSIC Granada), on behalf of a larger collaboration, report: "Following the detection by Swift of GRB 090404 (Ziaeepour et al. GCNC 9086), the 0.6-m Yock-Allen robotic telescope at the BOOTES-3 astronomical station in Blenheim (New Zealand) responded automatically, under non-favourable conditions (very high airmass). The first i'-band images taken 185s after the trigger time (15:59:35 UT) set a limiting magnitude of i' = 15 at this time. Follow-up observations at the 1.5-m telescope at Observatorio de Sierra Nevada in Granada have been obtained starting at 21:46 UT. No optical afterglow in the I-band is detected at the Swift/XRT enhanced position (Beardmore et al. GCNC 9088) down to the DSS2-infrared limit. A more detailed analysis is in progress." This message can be quoted. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9093 SUBJECT: GRB 090404: NOT observations DATE: 09/04/05 03:21:10 GMT FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst D. Malesani, J.P.U. Fynbo (DARK/NBI), P. Jakobsson (Univ. Iceland), A.J. Levan (Univ. Warwick), T. Liimets (Tartu Obs. and NOT), and Z. Banhidi (NOT), report on behalf of a larger collaboration: We observed the field of GRB 090404 (Ziaeepour et al., GCN 9086) with the NOT equipped with StanCam. Observations were carried out in the R and I bands, starting on 2009 Apr 5.035 UT (8.89 hr after the GRB). A total of 20 min exposure per filter were secured. We do not detect any object inside the revised XRT error circle (Beardmore et al., GCN 9088), down to limiting magnitudes R > 23.5, I > 22.3, assuming R = 19.19 and I = 18.84 for the USNO-B1 star 1255-0233978 at RA = 15:57:00.24, Dec = +35:31:28.0. We note the presence of a faint object (R = 22.8), possibly extended, just outside the XRT circle, at coordinates (J2000): RA = 15:56:57.72 Dec = +35:30:58.2 This position is 2.4" away from the XRT error circle center, which has currently an error radius of 1.4" (from http://www.swift.ac.uk/xrt_positions/index.php). We cannot state whether this object is related to GRB 090404. Further observations are ongoing. [GCN OPS NOTE(06may09): Per author's request, the institutional affiliation of Banhidi was changed to NOT.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9094 SUBJECT: Swift/UVOT observations of GRB090404 DATE: 09/04/05 12:56:40 GMT FROM: Patricia Schady at MSSL/Swift S. R. Oates (MSSL-UCL) and H. Ziaeepour report on behalf of the Swift/UVOT team: The Swift/UVOT began observing the field of GRB 090404 96 s after the BAT trigger (Ziaeepour et al., GCN Circ. 9086). No optical afterglow is detected in the initial UVOT exposures at the refined position of the X-ray afterglow (Beardmore et al., GCN Circ. 9088). The 3 sigma upper limits for the finding chart (fc) and summed exposures are reported below. Filter T_start (s) T_stop Exposure Mag/3UL --------------------------------------------------- white fc 96 246 147 < 20.92 white 591 1189 206 < 20.82 white 5121 18611 1084 < 21.80 u fc 310 559 246 < 20.17 u 715 1140 39 < 18.60 u 4710 35856 3049 < 21.56 v 641 1239 78 < 18.58 v 5531 11198 1150 < 20.37 b 565 1164 58 < 19.35 b 4915 35968 2078 < 21.50 uvw1 691 1116 39 < 18.45 uvw1 4504 45467 3237 < 21.47 uvm2 665 1091 58 < 18.54 uvm2 5736 41754 2695 < 21.42 uvw2 616 1214 78 < 19.09 uvw2 5326 6965 393 < 20.28 The above magnitudes are not corrected for the Galactic extinction corresponding to a reddening of E_{B-V} = 0.02 mag (Schlegel et al., 1998, ApJS, 500, 525). The photometry is on the UVOT flight system described in Poole et al. (2008, MNRAS, 383,627). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9095 SUBJECT: GRB 090404: further NOT observations DATE: 09/04/05 18:51:36 GMT FROM: Paolo D'Avanzo at INAF-OAB D. Malesani (DARK/NBI), P. D'Avanzo (Univ. Bicocca/INAF-Brera), P. Jakobsson (Univ. Iceland), J.P.U. Fynbo (DARK/NBI), T. Liimets (Tartu Obs. and NOT), and Z. Banhidi (NOT), report on behalf of a larger collaboration: Further to what reported in GCN 9093 (Malesani et al.), we observed again the field of GRB 090404 (Ziaeepour et al., GCN 9086) with the NOT. The object just outside the error circle noted in GCN 9093 is still well detected in the R band. Comparison of the two epochs, taken with mean times Apr 5.043 and Apr 5.214 UT (9.09 and 13.19 hr after the GRB, respectively), reveals no fading of the object by more than 0.1 mag. This corresponda to a limit on the decay index alpha < 0.25 (assuming F propto t^-alpha). The lack of significant variability and the location of the object outside the XRT error circle make this object unlikely related to GRB 090404. We acknowledge the NOT staff for excellent support. [GCN OPS NOTE(06may09): Per author's request, the institutional affiliation of Banhidi was changed to NOT.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9096 SUBJECT: GRB 090404: GROND upper limits DATE: 09/04/06 13:03:26 GMT FROM: Jochen Greiner at MPI P. Afonso, T. Kruehler, J. Greiner (MPE Garching) and S. Klose (TLS Tautenburg), report on behalf of the GROND team: GROND (Greiner et al. 2008, PASP 120, 405), mounted at the 2.2m ESO/MPI telescope at La Silla Observatory (Chile), observed the field of GRB 090404 (H. Ziaeepour et al. 2009, GCN #9086) simultaneously in the g'r'i'z'JHK bands. Observations started on April 5, at 06:19 UTC (14.4 h after the burst) and were carried out at air mass higher than 2.2. We obtained several short exposures with a total integration time of 80 min in g'r'i'z' and 72 min in JHK. We do not detect any new object in the stacked images inside the enhanced XRT error circle (Beardmore et al. 2009, GCN #9088), down to the following limiting magnitudes (all in the AB system): g' > 23.8 r' > 24.3 i' > 23.3 z' > 23.1 J > 22.3 H > 21.6 K > 20.3 The upper limits have been obtained using SDSS and 2MASS field stars as reference. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02 mag. We further note that the nearby object reported by D. Malesani et al. (2009, GCN #9093) is present in the SDSS catalog, and also detected with GROND at very similar magnitudes. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9099 SUBJECT: GRB 090404: nIR observations at Calar Alto DATE: 09/04/06 22:05:09 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia M. Jelínek, A. J. Castro-Tirado (IAA-CSIC Granada) and G. Bergond (CAHA Almería), on behalf of a larger collaboration, report: "Following the detection by Swift of GRB 090404 (Ziaeepour et al. GCNC 9086), JHKs observations (900-s each) were conducted on Apr 5.025 UT (8.5 hr after the burst) with the 3.5-m telescope (+ OMEGA2000) at the German-Spanish Calar Alto Observatory, under excellent conditions (0".9 seeing). At the Swift/XRT enhanced position (Beardmore et al. GCNC 9088) no nIR source is detected down to a limiting magnitude H = 21.5, in agreement with the limits reported by Afonso et al (GCNC 9096)." This message can be quoted. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9100 SUBJECT: GRB 090404: millimeter detection DATE: 09/04/06 22:15:32 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia A. J. Castro-Tirado (IAA-CSIC Granada), M. Bremer and J.-M. Winters (IRAM Grenoble), J. Gorosabel, S. Guziy, M. Jelínek, P. Kubánek (IAA-CSIC), A. de Ugarte Postigo (ESO Santiago) and D. Pérez-Ramírez (Univ. de Jaén), report: "Following the detection by Swift of GRB 090404 (Ziaeepour et al. GCNC 9086), millimeter observations were conducted on Apr 5.9 UT at the Plateau de Bure Interferometer. Consistent the Swift/XRT enhanced position (Beardmore et al. GCNC 9088) we clearly detect a millimeter source with a 108 GHz flux density of 1.1 mJy at coordinates RA(2000) = 15:56:57.52, Dec(2000) = +35:30:57.5 with (0.3",0.2") 1-sigma error in (RA,DEC). Pending of confirming its variability we propose this as the likely millimeter afterglow to GRB 090404. Together with the lack of optical and near-IR afterglows (Xin et al. GCNC 9090, Yock et al. GCNC 9092, Malesani et al. GCNC 9095, Afonso et al. GCNC 9096, Jelínek et al. GCNC 9099), this event strongly resembles the dark burst GRB 051022 (Castro-Tirado et al. 2007, A&A 475, 101). Further millimeter observations are scheduled." This message can be quoted. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9601 SUBJECT: GRB 090404: Deep optical imaging and possible host association DATE: 09/07/02 06:33:36 GMT FROM: Daniel Perley at U.C. Berkeley D. A. Perley, S. B. Cenko, and J. S. Bloom (UC Berkeley) report: We imaged the field of dark gamma-ray burst GRB 090404 (Ziaeepour et al., GCN 9086) using the Keck I telescope (+LRIS) on the night of 2009-06-25 (UT) for 1670 seconds in g-band and 1560 seconds in I-band under excellent (0.5 arcsecond) seeing and photometric conditions. The object outside the XRT error circle mentioned by Malesani et al. (GCN 9093, GCN 9095) is clearly detected as an extended source, likely a moderate-redshift galaxy (hereafter "G1"). A second, slightly fainter extended source ("G2") is also detected 3.5 arcseconds to its northeast, and the two sources appear to be connected by faint emission, perhaps a tidal bridge. Both sources are marginally detected in Sloan Digital Sky Survey archival images (see also GCN 9096). Additional faint, extended emission is detected just west of the brighter galaxy G1. The emission appears to be spread over several arcminutes in the g-band image, with an obvious "knot" located 1 arcsecond northeast of the millimeter afterglow position reported by Catro-Tirado et al. (GCN 9100). The extended region itself passes directly through the millimeter position. A false-color image of the field, with the millimeter and enhanced XRT positions (http://www.swift.ac.uk/xrt_positions/00348428/image.php) superimposed, is posted to: http://lyra.berkeley.edu/~dperley/090404/090404_gI.png We hypothesize that the extended emission may be a tidal tail extending from G1 as a result of interaction with its northeastern neighbor. Alternatively, the extended region may represent a very faint background host galaxy. Aperture photometry at the location of the millimeter afterglow gives a magnitude of g = 27.3 +/- 0.2. We encourage spectroscopy of the two bright galaxies G1 and G2 to determine their redshifts. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9602 SUBJECT: GRB 090404: Deep optical imaging and possible host association (correction) DATE: 09/07/02 07:38:53 GMT FROM: Daniel Perley at U.C. Berkeley D. A. Perley (UC Berkeley) reports: In the third paragraph of the previous circular (GCN 9601), the reference to the extended emission possibly associated with G1 being spread over several "arcminutes" should instead read that the emission is spread over several arcseconds. A g-band thumbnail image showing this emission (and the nearby "knot") more clearly is posted to: http://lyra.berkeley.edu/~dperley/090404/090404_g.png