//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8979 SUBJECT: GRB 090313 OA candidate DATE: 09/03/13 09:27:18 GMT FROM: Ryan Chornock at UC Berkeley R. Chornock, W. Li, and A. V. Filippenko report on behalf of the KAIT GRB team: The Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory slewed to the position of GRB 090313 and found a new bright source not present in the DSS: Coordinates (J2000) 13:13:36.21 +08:05:49.8 The bright moon is hindering follow up, but the source appears to be mag ~16 and is a few arcseconds away from a galaxy. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8980 SUBJECT: GRB 090313: Swift detection of a burst DATE: 09/03/13 09:34:52 GMT FROM: Jirong Mao at INAF-OAB J. Mao (INAF-OAB), A. P. Beardmore (U Leicester), P. A. Evans (U Leicester), C. Guidorzi (U Ferrara), E. A. Hoversten (PSU), H. A. Krimm (CRESST/GSFC/USRA), R. Margutti (Univ Bicocca&OAB), P. T. O'Brien (U Leicester), K. L. Page (U Leicester), P. Romano (INAF-IASFPA), T. Sakamoto (NASA/UMBC), G. Tagliaferri (INAF-OAB) and H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team: At 09:06:27 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 090313 (trigger=346386). The BAT on-board calculated location is RA, Dec 198.397, +8.107 which is RA(J2000) = 13h 13m 35s Dec(J2000) = +08d 06' 23" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a broad series of multiple peaks from approximately T-10 to T+40. The peak count rate was ~1300 counts/sec (15-350 keV), at ~4 sec after the trigger. Since this was an image trigger, the light curve shows only rather weak peaks. We will have more information upon receipt of the BAT event data in a few hours. Due to a Moon observing constraint, Swift cannot slew to the BAT position until 16:45 UT. There will thus be no prompt XRT or UVOT data for this trigger. Burst Advocate for this burst is J. Mao (jirong.mao AT brera.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: 8983 SUBJECT: GRB 090313, GROND observations DATE: 09/03/13 10:34:51 GMT FROM: Sylvio Klose at TLS Tautenburg A. C. Updike (Clemson University), S. Klose (Tautenburg), C. Clemens and J. Greiner (MPE Garching) report on behalf of the GROND team: We observed the field of GRB 090313 (Swift trigger 346386; Mao et al. 2009, GCN 8980) 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 09:13 UT on March 13, 7 minutes after the GRB trigger. We confirm that the afterglow candidate reported by Chornock et al. (GCN 8979) is bright in all bands. We measure the following preliminary magnitudes at a mean time of about 10 minutes after the burst (Vega mags): J = 14.0 +/- 0.1 H = 13.1 +/- 0.1 K = 12.3 +/- 0.1 calibrated against 2MASS field stars. Astrometry gives RA, DEC (J2000) = 13:13:36.21, +08:05:49.2 (+/- 0.5 arcsec). As already noted by Chornock et al., the afterglow is close to a bright galaxy. These are preliminary data. Data reduction is in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8984 SUBJECT: GRB 090313: SDSS object underlying the optical afterglow position DATE: 09/03/13 13:26:03 GMT FROM: Edo Berger at Harvard E. Berger (Harvard) reports: "Inspection of archival Sloan Digital Sky Survey images reveals a faint (and apparently extended) object near the position of the optical afterglow (GCN 8979) of GRB 090313 (GCN 8980). The object is located at: RA = 13:13:36.08 DEC = 08:05:51.06 (J2000) which is 2.3" away from the optical afterglow position provided by Chornock et al. (GCN 8979). The SDSS model magnitudes of this object are: g = 22.8+/-0.3 r = 21.6+/-0.16 i = 21.1+/-0.18 z = 20.7+/-0.4 A much brigher galaxy is located 17.8" away from the optical afterglow position at: RA = 13:13:35.29 DEC = 08:05:38.54 (J2000) which we consider to be the galaxy mentioned by Chornock et al. (given its brightness). The SDSS model magnitudes of this galaxy are: u = 17.07+/-0.01 g = 16.02+/-0.01 r = 15.57+/-0.01 i = 15.32+/-0.01 z = 15.14+/-0.01 A direct determination of the afterglow redshift is required in order to determine which of the two objects is the host galaxy." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8985 SUBJECT: GRB 090313: Sustained optical brightness DATE: 09/03/13 13:45:27 GMT FROM: Daniel Perley at U.C. Berkeley D. A. Perley, W. Li, R. Chornock, and A. V. Filippenko (UC Berkeley) report on behalf of the KAIT GRB team: We continued observing the position of the optical afterglow (Chornock et al., GCN 8979) of GRB 080313 (Mao et al., GCN 8980) with the Katzman Automatic Imaging Telescope (KAIT) in unfiltered and I-band images lasting until 2.9 hours after the trigger. In spite of significant contamination due to scattered light from the full moon 20 degrees away, we continue to (marginally) detect the afterglow in 30-second unfiltered and 120-second I-band exposures with a magnitude of I = 17.7 +/- 0.4 (calibrated relative to nearby USNO standards) at this time. Given the usually bright late-time optical afterglow, the equatorial and nearly anti-sun position, and the possibility of an association with the bright nearby galaxy (the second object mentioned in Berger et al., GCN 8984, which has a spectroscopic redshift of z=0.0235 according to SDSS), and the unclear high-energy classification of this object (Sakamoto et al., GCN 8982) we strongly encourage continued follow-up in spite of the presence of the nearby moon. [GCN OPS NOTE(13mar09): Per author's request, please see GCN 8988 that explains the mistaken sakamoto reference and the high-energy statement in the last sentence, as explained in the corerction GCN 8988.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8986 SUBJECT: GRB 090313: Swift-BAT refined analysis DATE: 09/03/13 13:48:31 GMT FROM: Scott Barthelmy at NASA/GSFC T. Sakamoto (GSFC/UMBC), 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), J. Mao (INAF-OAB), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. 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 090313 (trigger #346386) (Mao, et al., GCN Circ. 8980). The BAT ground-calculated position is RA, Dec = 198.400, 8.086 deg, which is RA(J2000) = 13h 13m 36.0s Dec(J2000) = +08d 05' 10.7" with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 15%. The mask-weighted light curve shows emission starting before T-100 sec at which time the burst location came into the BAT FOV during a pre-programmed target slew. BAT triggered on the peak starting at ~T-20 sec, peaking at ~T+10 sec, and ending at ~T+90 sec. T90 (15-350 keV) is 78 +- 19 sec (estimated error including systematics). The time-averaged spectrum from T-21.3 to T+66.6 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.91 +- 0.29. The fluence in the 15-150 keV band is 1.4 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+4.86 sec in the 15-150 keV band is 0.8 +- 0.3 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/346386/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8988 SUBJECT: GRB 090313: Sustained optical brightness (correction) DATE: 09/03/13 13:55:10 GMT FROM: Daniel Perley at U.C. Berkeley D. A. Perley (UC Berkeley) reports: In the preceding circular reporting on the continued optical brightness at ~3 hours, the reference to Sakamoto et al. (GCN 8982) is in error. That circular addresses GRB 090309, not GRB 090313. As is clear in Sakamoto et al. (GCN 8986), this event is clearly a long GRB (T90 = 78 +- 19 sec). I apologize for any confusion. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8989 SUBJECT: GRB 090313: Faulkes Telescope North observations DATE: 09/03/13 18:53:56 GMT FROM: Cristiano Guidorzi at Ferrara U,Italy C. Guidorzi (U. Ferrara), A. Melandri, I. A. Steele (Liverpool JMU), A. Gomboc (U. Ljubljana), D. Bersier, C.J. Mottram, C.G. Mundell, R.J. Smith (Liverpool JMU), P. O'Brien, N. Bannister, N. Tanvir (U. Leicester) on behalf of a large collaboration report: The 2-m Faulkes Telescope North (Hawaii) automatically reacted to the Swift burst GRB 090313 (trigger=346386, Mao et al. GCN 8980). Observations started about 168 s after the trigger time with filters BRi. We confirm the detection of the optical counterpart (Chornock et al. GCN 8979, Updike et al. GCN 8983, Perley et al. GCN 8985). The afterglow magnitude was observed to rise and peak around 1.3 ks post burst, followed by a rapid decay out to ~ 10 ks. Further observations suggest a subsequent flattening. Filter Tmid(s) Exposure(s) Mag ------------------------------------------------ R 880 60 16.12 +/- 0.07 R 1260 120 15.60 +/- 0.05 R 12290 300 18.20 +/- 0.20 ------------------------------------------------ Magnitudes are calibrated with respect to the nearby USNOB1 star 13:13:35.789 +08:05:24.11 assuming its catalogue value of R2=17.08. Further observations are going to be attempted. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8990 SUBJECT: GRB 090313: Swift/UVOT upper limits DATE: 09/03/13 22:50:45 GMT FROM: Patricia Schady at MSSL/Swift P.Schady (MSSL-UCL) S.T. Holland (CRESST/GSFC/USRA) and J. Mao (INAF-OAB) report on behalf of the Swift/UVOT team: The Swift/UVOT began observing the field of GRB 0903013 once it came out of Moon constraint, 27ks after the BAT trigger (Mao et al., GCN Circ. 8980). There is no afterglow detection in any of the b, u or uvw1 UVOT filter observations taken at the optical afterglow position reported by Chornock et al. (GCN 8979), although by coadding all filters into a single exposure, a source is marginally detected at the 2-sigma level. The 3-sigma upper limits for GRB090313 within each UVOT filter are as follows: Filter T_mid(hrs) Exp(s) 3-sig Mag UL u 7.98 223 > 20.81 b 7.82 885 > 21.36 uvw1 7.57 886 > 21.32 where Tmid is the weighted mean time of the observations. The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8991 SUBJECT: GRB 090313: Swift-XRT refined analysis DATE: 09/03/13 23:00:22 GMT FROM: Jirong Mao at INAF-OAB J. Mao & R. Margutti (INAF-OAB) report on behalf of the Swift-XRT team: We have analysed 2 ks of XRT data for GRB 090313 (Mao et al. GCN Circ. 8980), from 26.8 ks to 28.6 ks after the BAT trigger. All the data were taken in Photon Counting (PC) mode. Using 2038 s of XRT Photon Counting mode data and 1 UVOT image, 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 = 198.40130, 8.09730 which is equivalent to: RA (J2000): 13 13 36.30 Dec (J2000): +08 05 50.4 with an uncertainty of 1.8 arcsec (radius, 90% confidence). The optical candidate (Chornock et al. GCN 8979 and Updike et al. GCN 8983) lies within the XRT error circle. The lightcurve can be modeled as a single power-law with an index around 5.4. Given the present data set the value of this parameter is affected by a large uncertainty. The PC mode spectrum can be fit with an absorbed simple power-law, with a photon index of 2.12 ± 0.33 and an absorbing column density of 1.29 ± 0.97 e21 cm-2, in excess of the Galactic value of 2.10e20 cm-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 5.1e-11 (5.9e-11) erg cm-2 count-1. Given the very uncertain power-law decay index, no firm prediction of the lightcurve can be made. The results of the automatic XRT analysis are available online at http://www.swift.ac.uk/xrt_products/00346386. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8992 SUBJECT: GRB 090313: Ongoing plateau phase DATE: 09/03/13 23:39:20 GMT FROM: Antonio Deugarte at IAA-CSIC A. de Ugarte Postigo (ESO), J. Gorosabel, A. Sota, A.J. Castro-Tirado (IAA-CSIC) report on behalf of a larger collaboration: We have observed the field of GRB 090313 (Mao et al. GCNC 8980) with the 1.5m OSN telescope (Granada, Spain) starting on 22:29 UT (13.4 hours after the burst). Our I-band images show that the optical afterglow reported by Chornock et al. (GCNC 8979) is still bright. Preliminary photometry yields I=17.7+/- 0.3. This would imply that the plateau phase reported by Perley et al. (GCN 8985) is still ongoing, half a day later. Further observations are encouraged //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8993 SUBJECT: GRB 090313 optical observations DATE: 09/03/14 01:47:12 GMT FROM: AAVSO GRB Network at AAVSO Markku Nissinen (Varkaus, Finland) reports to the AAVSO High Energy Network the following optical observations of GRB 090313 (Chornock, Li, and Filippenko, GCN #8979; Mao et al., GCN #8980): Markku Nissinen reports the detection of the optical counterpart of GRB 090313 using the GRAS-04 telescope sited in Mayhill, NM, USA. A number of unfiltered observations with varying exposure times were made using the 0.25-meter telescope with an SBIG ST8XE CCD camera; observations began approximately 1 hour post burst. The afterglow was detected in all frames with astrometric positions matching those given by Chornock, Li, and Filippenko (GCN #8979) and Updike et al (GCN #8983) to within positional errors. The following unfiltered magnitudes were obtained from the observations using USNO-A2.0 U0975_07146255 (R magnitude = 15.9) as the comparison: obs midpoint(UT) exptime mag(CR) mag.err 2009-03-13 10:14:41 360 sec 16.5 +/- 0.3 (3 x 120 sec) 2009-03-13 10:27:59 300 sec 16.7 +/- 0.3 2009-03-13 10:39:53 600 sec 16.9 +/- 0.3 A FITS image of the 300-second observation is available at the following URL: ftp://ftp.aavso.org/grb/MarkkuNissinen_GRB090313_2454904.28608_.fits The AAVSO thanks the Curry Foundation for their continued support of the AAVSO International High Energy Network. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8994 SUBJECT: GRB 090313: Gemini-S redshift DATE: 09/03/14 05:45:25 GMT FROM: Daniel Perley at U.C. Berkeley R. Chornock, D. A. Perley, S. B. Cenko, J. S. Bloom, B. Cobb (UC Berkeley), and J. X. Prochaska (UCO/Lick) report: We began a spectroscopic integration on the afterglow of GRB 090313 (Chornock et al., GCN 8979; Mao et al., GCN 8980) using Gemini-South (GMOS) starting at 04:20 UT on 2009-03-14, approximately 19 hours after the trigger. We conducted a series of two exposures of 600 seconds each using the R400 grating, covering a wavelength range of approximately 3900 to 8140 Angstroms. Additional exposures are in progress. We detect transitions corresponding to C IV, Al II, O I, Si II, Si IV, and Fe II, as well as a broad absorption feature which we associate with Lyman-alpha, at a common redshift of z=3.375. We also detect Si II* at this redshift, identifying this as the redshift of the GRB. While ruling out an association with the bright nearby SDSS galaxy, this redshift suggests an extraordinary late-time afterglow luminosity. We continue to encourage sustained late-time follow-up of this event, which given its continued brightness (Perley et al., GCN 8985; de Ugarte Postigo et al., GCN 8992) is likely to continue to be observable to small-aperture telescopes for an extended period of time. We thank the Gemini staff for conducting these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8995 SUBJECT: GRB 090313 - PAIRITEL NIR detections DATE: 09/03/14 06:35:06 GMT FROM: Adam Morgan at PSU/Swift-UVOT A. N. Morgan, J. S. Bloom, D. A. Perley (UC Berkeley), and D. Starr (UCB, LCOGT) report: We observed the optical afterglow of GRB 090313 (Mao et al. 2009, GCN 8980) with PAIRITEL beginning at 2009-03-13 09:39 UT, 31 minutes after the Swift Trigger. We detect the afterglow (Chornock et al., GCN 8979) in all 111 47-second mosaics of 7.8 second simultaneous exposures in the J, H, and Ks taken throughout the night. Preliminary lightcurves indicate a shallowing of the temporal decay rate during the 3.5 hours over which the afterglow was observed. The preliminary photometry yields: post_burst t_mid (hr) exp(s) filt mag merr 0.941 1883 J 14.7 0.1 0.941 1883 H 13.8 0.1 0.941 1883 K 12.8 0.1 2.302 2331 J 15.6 0.1 2.302 2331 H 14.6 0.1 2.302 2331 K 13.8 0.1 3.512 1860 J 15.9 0.1 3.512 1860 H 15.4 0.1 3.512 1860 K 14.1 0.1 No correction for Galactic extinction has been made to the above reported values. Further observations are being taken tonight. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8997 SUBJECT: GRB 090313: Gemini-S photometry DATE: 09/03/14 10:38:18 GMT FROM: Daniel Perley at U.C. Berkeley D. A. Perley (UC Berkeley) reports on behalf of a larger collaboration: Following our spectroscopic integration on the optical afterglow of GRB 090313 (GCN 8994), we acquired one 60s frame in each of g, r, i, and z filters using Gemini-S (GMOS) in imaging mode between 05:11 and 05:18 UT (20.07 hours after the burst). We report the following magnitudes: g = 21.62 +/- 0.08 r = 20.12 +/- 0.03 i = 19.50 +/- 0.05 z = 19.03 +/- 0.05 The optical SED is well-fit assuming a moderate (A_V ~< 0.4) amount of SMC-like dust extinction. The presence of a 2175 A dust feature is strongly ruled out by the z-band measurement. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8998 SUBJECT: GRB 090313: TAROT La Silla observatory optical detection DATE: 09/03/15 00:38:51 GMT FROM: Alain Klotz at CESR-CNRS Klotz, A. (CESR-OMP), Gendre, B. (LAM-OAMP), Boer M. (OHP-OAMP), Atteia J.L. (LATT-OMP) report: We imaged the field of GRB 090313 detected by Swift (trigger 346386) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile. The observations started 104s after the GRB trigger The elevation of the field decreased from 37 degrees above horizon and weather conditions were good but the moon was at 20 deg. The first image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39). We do not detect the OT reported by Chornock et al. (GCNC 8979) with a limiting magnitude of: t0+104s to t0+164s : R > 15.3 The second image is 30.0s exposure in tracking mode: t0+186s to t0+216s : R > 16.6 We co-added a series of exposures. The OT is detected: t0+186s to t0+421s : R = 17.1 All images are unfiltered. Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8999 SUBJECT: GRB 090313: Light curve steepening DATE: 09/03/15 04:39:47 GMT FROM: Antonio Deugarte at IAA-CSIC A. de Ugarte Postigo (ESO), J. Gorosabel, A. Sota, A.J. Castro-Tirado (IAA-CSIC), S. McBreen (Univ. College Dublin) and M.R. Zapatero-Osorio (IAC) report on behalf of a larger collaboration: We continued the observations of the afterglow (Chornock et al. GCNC 8979) of GRB 090313 (Mao et al. GCNC 8980) from the 1.5m OSN telescope at Sierra Nevada Observatory (Granada, Spain) in I-band, the 0.8m IAC80 telescope at Teide Observatory (Tenerife, Spain) in R-band and the 2.5m NOT telescope in nIR bands. The observations show how the light curve maintains its brightness until at least 0.8341 days after the burst, where our last image from OSN shows the afterglow at I=17.9+/-0.2. This is still stable as compared to the report of Perley et al. (GCNC 8985) 0.12 days after the burst and our previous report (de Ugarte Postigo et al. GCNC 8992) 0.56 days after the burst. We note that our new magnitude is somehow brighter than the one reported by Perley et al. at a similar epoch (GCNC 8997). This could be due to a calibration issue. We are using USNO-B1.0 stars as reference. From the IAC80 we observe the burst during the plateau 0.6482 days after the burst at a magnitude of 19.1+/-0.1. At NOT telescope we clearly detect the bright afterglow in J and Ks bands with NOTCAM 0.7989 days after the burst at a magnitude of Ks=15.2+/-0.3. We used 2MASS for the calibration, which is the main source of uncertainty in this value. Observations continued the following night, where we see a strong drop in the magnitude of the afterglow, which can be detected at I=20.2 +/- 0.4, 1.5547 days after the burst, indicating the presence of a break in the light curve. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9000 SUBJECT: GRB 090313: WSRT Radio Observations DATE: 09/03/15 16:16:34 GMT FROM: Alexander van der Horst at NASA/MSFC A.J. van der Horst (NASA/MSFC/ORAU) and A.P. Kamble (University of Amsterdam) report on behalf of a larger collaboration: "We observed the position of the GRB 090313 afterglow at 4.9 GHz with the Westerbork Synthesis Radio Telescope at March 14 21.06 UT to March 15 7.27 UT, i.e. 1.50 - 1.92 days after the burst (GCN 8980). We do not detect a radio source at the position of the optical counterpart (GCN 8979). The three-sigma rms noise in the map around that position is 114 microJy per beam. The formal flux measurement for a point source at the position of the optical counterpart is 26 +/- 38 microJy. We would like to thank the WSRT staff for scheduling and obtaining these observations." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9001 SUBJECT: GRB 090313: Additional Gemini-S photometry DATE: 09/03/15 20:00:06 GMT FROM: Daniel Perley at U.C. Berkeley D. A. Perley, S. B. Cenko, J. S. Bloom, W. Li, and B. E. Cobb (UC Berkeley) report: We conducted additional imaging observations of the optical afterglow of GRB 090313 (GCN 8979, GCN 8780) consisting of 2x90 seconds in g, r, i, and z filters on Gemini-S (GMOS) between 08:39 and 08:58 UT on 2009-03-15 (47.7 hours after the burst). At this time we measure an afterglow magnitude (calibrated using SDSS stars in the field) of r = 21.77 +/- 0.05, confirming the steepening in the decay reported by de Ugarte Postigo et al. (GCN 8999). The amount of fading relative to our first epoch (GCN 8997) is consistent across all four filters. We measure an average decay index (F ~ t^-alpha) of alpha=1.77 over this interval. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9002 SUBJECT: GRB 090313: MITSuME Okayama observation DATE: 09/03/16 09:58:21 GMT FROM: Michitoshi Yoshida at Okayama Astrophysical Obs M. Yoshida, D. Kuroda, K. Yanagisawa, 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 090313 (Mao et al. GCN 8980) with the optical three-color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory. The observation started on 2009-03-14 14:27:51 UT (29.34 hours after the alert). We detected a point source at the position of the X-ray - optical - IR afterglow (Chornock and Filippenko GCN 8979; Mao et al. GCN 8991; Updike et al. GCN 8983; Vaalsta et al. GCN 8996; de Ugarte Postigo et al. GCN 8992, GCN 8999; Perley GCN 8997; Perley et al. GCN 9001) in Ic band. Photometric result is listed below. We used GSC2.3 catalog for flux calibration. Mid-UT Td Exp.Time Ic ------------------------------------------------------------- 2009-03-14 16:30:24 31.3775 hr 60sec x 171 19.3 +/- 0.2 ------------------------------------------------------------- Our result and previous reports (Vaalsta et al. GCN 8996; Perley GCN 8997; de Ugarte Postigo et al. GCN 8999) show that the afterglow maintained its brightness from 10 hours to 30 hours after the burst. de Ugarte Postigo et al. (GCN 8999) and Perley et al. (GCN 9001) reported steep decline of the I band magnitude of the object after our observation. Thus the break point of the light curve may exist at around 31 hours after the burst. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9003 SUBJECT: Radio detection of GRB090313 DATE: 09/03/16 10:17:38 GMT FROM: Guy Pooley at MRAO, Cambridge, UK Guy Pooley, on behalf of the AMI collaboration (Cavendish Astrophysics, University of Cambridge) reports: We detected GRB 090313 in an observation with the AMI Large Array in the frequency range 14.5 to 17.5 GHz. The observation was on 2009 Mar 16 from 02h00m to 04h24m (2d 18h after the burst: Mao et al, GCN 8980). We measured a flux density of 820 microJy with an rms noise of 71 microJy, at a position 13h13m36.0s +08d05'47", consistent with the optical position (Chornock et al GCN8979). The resolution is 63"x24" at p.a. 24deg. This message may be quoted. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9005 SUBJECT: GRB 090313: detection with CARMA in 3mm band DATE: 09/03/16 15:21:35 GMT FROM: Poonam Chandra at U Virginia/NRAO D. C.-J. Bock (CARMA), P. Chandra (RMC), D. A. Frail (NRAO), and S. R. Kulkarni (Caltech) report on behalf of a larger collaboration: "We observed the field of view of GRB 090313 (GCN 8980) with the Combined Array for Research in Millimeter-Wave Astronomy (CARMA) at a frequency of 92.5 GHz at the mean observation time of 2009 March 14, 0930 UT, within a day of detection by the Swift. We detect the GRB at the KAIT optical afterglow position (GCN 8979) with a flux density of 4.0+/-0.6 mJy. The map rms noise is 0.17 mJy. We acknowledge excellent support from the staff and observers at CARMA." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9006 SUBJECT: Further Swift/UVOT observations of GRB 090313 DATE: 09/03/16 20:55:05 GMT FROM: Patricia Schady at MSSL/Swift P.Schady (MSSL-UCL), F.E.Marshall (NASA/GSFC) and J. Mao (INAF-OAB) report on behalf of the Swift/UVOT team: Following on from GCN 8990 (Schady et al.), we report on Swift/UVOT observations of GRB 090313 for all optical and ultraviolet filters. A fading source is detected in the v filter and marginally in the b-band filter at a position consistent with the optical afterglow reported by Chornock et al. (GCN 8979). These observations are in agreement with the spectroscopic redshift z=3.375 (Chornock et al., GCN 8994). The magnitudes and 3-sigma upper limits for GRB 090313 within each co-added UVOT filter are as follows: Filter T_mid (hrs) Exp (s) Mag/3-sigma UL v 11.0 551 20.10 +/- 0.30 (3.6 sigma) b 11.2 770 21.50 +/- 0.38 (2.8 sigma) u 8.1 1024 > 21.44 uvw1 8.6 1771 > 21.78 uvm2 9.3 886 > 21.22 uvw2 10.9 886 > 21.58 where T_mid is the weighted mean time of the observations. The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998). All photometry is on the UVOT photometry system described in Poole et al. (2008, MNRAS, 383, 627). In addition, we note an error in GCN 8990 (Schady et al.), where we mistakenly labelled the results for the u filter as b and vice versa. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9007 SUBJECT: Further radio observation of GRB 090313 DATE: 09/03/17 09:17:34 GMT FROM: Guy Pooley at MRAO, Cambridge, UK Guy Pooley, on behalf of the AMI collaboration (Cavendish Astrophysics, University of Cambridge) reports further to GCN9003: We observed the field of GRB 090313 again with the AMI Large Array in the frequency range 14.5 to 17.5 GHz. The observation was on 2009 Mar 16 23h51m to Mar 17 02h50m (3d 18h after the burst). We measured a flux density of 860 microJy with an rms noise of 75 microJy, at a position consistent with that reported in GCN9003. The spectrum over that frequency band is consistent with a spectral index of zero, but is not well constrained because of the relatively narrow bandwidth and faint flux. Since the flux density has not changed significantly, while radio detections of GRBs at this early stage are often highly variable, the association of this source with the GRB is currently not confirmed. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9008 SUBJECT: GRB 090313, SMARTS optical/IR observations DATE: 09/03/18 01:06:29 GMT FROM: Bethany Cobb at UC Berkeley B. E. Cobb (UC Berkeley) reports: Using the ANDICAM instrument on the 1.3m telescope at CTIO, we obtained optical/IR imaging of the error region of GRB 090313 (GCN 8980, Mao et al.) over four epochs (with UT mid-exposure times of: 2009-03-14 04:27, 2009-03-14 06:55, 2009-03-15 06:30 & 2009-03-17 05:07). Total summed exposure times for each observation amounted to 36 minutes in R and 30 minutes in J. The GRB afterglow (e.g. GCN 8979, Chornock et al., GCN 8983, Updike et al. and GCN 8985, Perley et al.) appears in our imaging to be fading rapidly after ~19 hours post-burst: mid-exposure time (hours post-burst) R mag J mag 19.33 19.70+/-0.04 17.38+/-0.15 21.81 19.90+/-0.04 17.62+/-0.15 45.38 21.57+/-0.12 18.91+/-0.16 92.01 > 22.5 > 19.8 These preliminary magnitudes are calibrated using Landolt standard stars in the optical and a 2MASS star in the IR. This rapid fading follows the initial plateau phase that was reported by Perley et al. (GCN 8985) and de Ugarte Postigo et al. (GCN 8992). This fading is consistent with the light curve break noted by de Ugarte Postigo et al. (GCN 8999), though the break appears to occur in this imaging somewhat earlier than suggested by Yoshida et al. (GCN 9002). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9011 SUBJECT: GRB090313: radio detection with the VLA DATE: 09/03/19 15:40:15 GMT FROM: Poonam Chandra at U Virginia/NRAO D. A. Frail (NRAO), and P. Chandra (RMC) report on behalf of a larger collaboration: "We observed the field of view of GRB 090313 (GCN 8980) with the Very Large Array (VLA) in 8.46 GHz frequency on 2009 March 19.23 UT. We detect a radio source at position (J2000) RA 13:13:36.189, Dec 08:05:49.75, which is within 0.3" of the KAIT optical afterglow position (GCN 8979). The GRB flux density at 8.46 GHz band is 269+/-31 uJy. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9012 SUBJECT: GRB 090313: VLT spectroscopy DATE: 09/03/19 22:51:47 GMT FROM: Paolo D'Avanzo at INAF-OAB C. C. Thoene (INAF-OAB), P. D'Avanzo (Univ. Bicocca & INAF-OAB), D. Fugazza (INAF-OAB), A. de Ugarte Postigo (ESO), V. D'Elia, S. Piranomonte (INAF-OAR), S. Covino, S. Campana (INAF-OAB), G. Chincarini (Univ. Bicocca) report, on behalf of the MISTICI collaboration: We observed the optical afterglow of GRB 090313 (Chornock et al. GCN 8979; Mao et al. GCN 8980) with the ESO VLT about 1.9 days after the burst with the FORS2 camera in spectroscopic mode. We took 4 exposures of 20 min each with the 600I grism covering the range 6800-9300 Angstrom with a resolution of R=1500. While we confirm the redshift reported by Chornok et al. (GCN 8994), we also report the detection of a broad double absorption feature around observed lambda 7830 and 7840 angstrom that does not fit any transition at the GRB redshift (z = 3.375). This double feature can be interpreted as Mg II 2796,2803, each consisting of 2 velocity components with a separation of about 300 km/s, and could be a signature of an intervening system at z ~ 1.8. We cannot confirm the presence of Mg I 2852 at z = 1.8 due to the possible overlap with Mg I 1827 absorption at the redshift of the GRB. We acknowledge excellent support from the ESO staff, in particular Yuri Beletsky. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9015 SUBJECT: X-shooter observations of GRB 090313 DATE: 09/03/23 02:58:03 GMT FROM: Antonio Deugarte at IAA-CSIC A. de Ugarte Postigo, S. D’Odorico (ESO PI), J. Vernet, A. Modigliani, S. Ramsay from ESO Commissioning team; S. Covino (INAF Brera), H. Flores (Obs. Paris), J. Fynbo, J. Hjorth (NBI/DARK, U. Copenhagen) and R.A.M.J. Wijers (Astr. Institute, U. Amsterdam) from the X-shooter GRB team; F. Hammer (Obs. Paris), L. Kaper (Astr. Institute, U. Amsterdam), P. Kjaergaard (NBI, U. Copenhagen), S. Randich (INAF Arcetri) as X-shooter PIs; P.J. Groot (Radboud Univ. Nijmegen) from the X-shooter Science Team. On March 15.22 UT we initiated observations of GRB 090313 (Chornock et al., GCNC 8979; Mao et al., GCNC 8980) with X-shooter at the ESO Melipal telescope of the Paranal Observatory. X-shooter is the first of the second-generation VLT instruments and includes three Echelle spectrographs, the Ultraviolet/Blue (UVB), the Visible (VIS) and the Near Infrared (NIR), which combined provide a fixed spectral format and cover in one shot the spectral range 3000 - 24000 A at medium spectral resolution (R = 4000 - 10000 depending on the arm and slit width). The mean epoch of the observation was 45.3 hours after the burst, when the afterglow had faded to R ~ 21.6 (Perley et al. GCNC 9001; Cobb et al. GCNC 9008). In the 4 x 1500 s combined spectrum we clearly detect continuum above 5580 A with several absorption lines; below this, the signal is dominated by background emission produced by the nearby Moon (90 % illumination at 37 deg from the field). The spectrum indicates an absorption redshift of z = 3.3721 ± 0.0004 (consistent with that measured by Chornock et al., GCNC 8994 and Thoene et al., GCNC 9012) through the detection of Si II (1304.5), C II (1334.5), Si IV (1393.8), Si IV (1402.8), Si II (1526.7), C IV (1548.2,1550.8), Fe II (1608.5), Fe II (1611.2), Al III (1854.7), Al III (1862.8), Zn II (2062.6), Fe II (2600.1), Mg II (2796.3, 2803.5) and Mg I (2853.0). The intervening system identified by Thoene et al. (GCNC 9012) is resolved into multiple components through the detection of Fe II, Mg II and Mg I lines with its main absorption at redshift 1.800. A further system at z = 1.959 shows Fe II, Mg II and Mg I absorption. The spectra of GRB 090313 will be made public on the ESO web as other data of scientific relevance obtained during the commissioning of the instrument. [GCN OPS NOTE923mar09): Per author's request, the Groot-author's affiliation was changed.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9016 SUBJECT: GRB 090313: WSRT Radio Detection DATE: 09/03/23 05:45:35 GMT FROM: Alexander van der Horst at NASA/MSFC A.J. van der Horst (NASA/MSFC/ORAU) and A.P. Kamble (University of Amsterdam) report on behalf of a larger collaboration: "We reobserved the position of the GRB 090313 afterglow at 4.9 GHz with the Westerbork Synthesis Radio Telescope at March 20 18.89 UT to March 21 6.88 UT, i.e. 7.41 - 7.91 days after the burst (GCN 8980). We detect a radio source with a flux density of 165 +/- 30 microJy at the position of the optical counterpart (GCN 8979). We would like to thank the WSRT staff for scheduling and obtaining these observations." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9017 SUBJECT: Further 15GHz observations of GRB090313 DATE: 09/03/23 12:34:06 GMT FROM: Guy Pooley at MRAO, Cambridge, UK Guy Pooley, on behalf of the AMI collaboration (Cavendish Astrophysics, University of Cambridge) reports: Further observations of the field of GRB090313 have been made with the AMI Large Array in the frequency range 14.5 to 17.5 GHz. Including those already reported in GCN 9003 and 9007, after minor recalibration, the flux densities measured were 2009 Mar 16.13 800 +- 80 microJy 2009 Mar 17.06 882 +- 77 2009 Mar 18.05 815 +- 129 2009 Mar 20.16 718 +- 97 2009 Mar 23.05 655 +- 69 Observations lasted between 1 and 3 h, and the resolution is approximately 60x25 arcsec. The position is consistent with that of the optical transient (Chornock et al GCN8979). This message may be quoted. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9606 SUBJECT: GRB 090313: optical observations DATE: 09/07/03 10:53:29 GMT FROM: Graziella Pizzichini at IASF/CNR,Bologna E. Maiorano, G. Pizzichini (INAF/IASF Bologna), C. Bartolini, G. Greco, A. Guarnieri, A. Mantegna, A. Piccioni (Bologna University), D. Nanni (INAF/OAR and Second University of Rome "Tor Vergata"), F. Terra (Second University of Roma "Tor Vergata"), R. Gualandi (Bologna Observatory) report: During the night between 09/03/13 and 09/03/14 we observed the OT of GRB090313 (Chornock et al., GCN 8979, Mao et al., GCN 8980) with the 1.52 cm telescope of the Bologna Observatory in Loiano. Airmass 1.24 and seeing less than 2" . Observations were disturbed by the moon. The images were calibrated using the star quoted by Guidorzi et al., GCN 8989. By summing 9 images in filter R, with a total duration of 2280s obtained on March 14 between 00:41:11 and 01:27:59 UT, (mid exposure time 15.97 hr after the burst) we find R mag = 19.26 +/- 0.15 Our image has been posted in our public directory from where it can be retrieved by sftp using sftp publicGRB@137.204.66.221 password: GRB_bo cd GRB090313