//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9438 SUBJECT: GRB 090530: Swift detection of a burst with an optical counterpart DATE: 09/05/30 03:30:01 GMT FROM: Scott Barthelmy at NASA/GSFC J. K. Cannizzo (NASA/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (NASA/UMBC), C. Gronwall (PSU), S. T. Holland (CRESST/USRA/GSFC), V. Mangano (INAF-IASFPA), C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), T. Sakamoto (NASA/UMBC), B. Sbarufatti (INAF-IASFPA), M. H. Siegel (PSU), M. Stamatikos (NASA/ORAU) and T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team: At 03:18:18 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 090530 (trigger=353567). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 179.395, +26.584 which is RA(J2000) = 11h 57m 35s Dec(J2000) = +26d 35' 01" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single peak with a duration of about 10 sec. The peak count rate was ~5000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 03:19:33.1 UT, 74.7 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source located at RA, Dec 179.41927, 26.59282 which is equivalent to: RA(J2000) = 11h 57m 40.62s Dec(J2000) = +26d 35' 34.2" with an uncertainty of 3.9 arcseconds (radius, 90% containment). This location is 84 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (1.78e+20 cm^-2, Kalberla et al. 2005), with an excess column of 2.1 (+2.01/-1.71) x 10^21 cm^-2 (90% confidence). The initial flux in the 2.5 s image was 6.42e-10 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 83 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 11:57:40.50 = 179.41876 DEC(J2000) = +26:35:38.6 = 26.59405 with a 90%-confidence error radius of about 0.75 arc sec. This position is 4.7 arc sec. from the center of the XRT error circle. The estimated magnitude is 17.39 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02. Burst Advocate for this burst is J. K. Cannizzo (cannizzo AT milkyway.gsfc.nasa.gov). 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: 9439 SUBJECT: GRB 090530A: ROTSE-III Detection of Optical Counterpart DATE: 09/05/30 03:30:24 GMT FROM: Heather Flewelling at IfA/Hawaii H. Flewelling (IfA), B. E. Schaefer (Louisiana State), Shashi Pandey (UMich) report on behalf of the ROTSE collaboration: ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB 090530A (Swift trigger 353567). The first image was at 03:18:35.8 UT, 17.4 s after the burst (6.8 s after the GCN notice time). The unfiltered images are calibrated relative to USNO A2.0. We detect a new object, not visible in the DSS (second epoch), with coordinates: 11:57:40.5 +26:35:37.9 (J2000), with positional uncertainty of 1" or better start UT mag mlim(of image) ---------------------------------- 03:18:42.7 16.0 16.2 A jpeg image is available at http://www.rotse.net/images/gsb353567_3b00_img.jpg Note that the object marked 48 is the candidate in question. Continuing observations are in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9441 SUBJECT: GRB 090530: GRAS002 optical observations DATE: 09/05/30 09:13:47 GMT FROM: Veli-Pekka Hentunen at Taurus Hill Obs,A95 Markku Nissinen (Taurus Hill Observatory) and Veli-Pekka Hentunen (Taurus Hill Observatory) report: We used Global-rent-a-scope GRAS002 Tak Mewlon 0.30m telescope with SBIG ST-8E CCD at RAS Observatory Mayhill H06 (New Mexico, USA) for follow-up observations of GRB090530 (J.K. Cannizzo et al., GCN 9438). The observations were started on May 30, at 05:30 UTC (2.2 hours after the burst) and stopped on May 30, at 06:16 UTC. Four unfiltered 600 seconds images were taken. We detected very faint optical afterglow object at the position of RA 11h 57m 39s.8 and Dec +26o 35' 47" (J2000) with possitional uncertainty of 10" with respect to POSSII F/USNO-B1.0. This is in correlation with ROTSE-III optical counterpart position (H. Flewelling et al., GCN 9439). Upper limit for the observations is >20.2 mag (3UL). Quoted upper limit has been derived using POSSII F and USNO-B1.0 field stars as reference. Filter Tmid(s) Exp(s) Mag (CR) USNO-B1.0 u 05:55:15 4x600 19.7 A jpeg preview of the observation showing the position of the afterglow is at this URL: http://cutenews.kassiopeia.net/data/upimages/GRB090530A_new.jpg //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9442 SUBJECT: GRB 090530: GRAS002 refined OA analysis DATE: 09/05/30 10:25:37 GMT FROM: Veli-Pekka Hentunen at Taurus Hill Obs,A95 Markku Nissinen (Taurus Hill Observatory) and Veli-Pekka Hentunen (Taurus Hill Observatory) report: We used Global-rent-a-scope GRAS002 Tak Mewlon 0.30m telescope with SBIG ST-8E CCD at RAS Observatory Mayhill H06 (New Mexico, USA) for follow-up observations of GRB090530 (J.K. Cannizzo et al., GCN 9438). The observations were started on May 30, at 05:30 UTC (2.2 hours after the burst) and stopped on May 30, at 06:16 UTC. Four unfiltered 600 seconds images were taken. We detected very faint optical afterglow object at the position of RA 11h 57m 40s.6 and Dec +26o 35' 38".7 (J2000) with respect to POSSII F/USNO-B1.0 and this is in good correlation with ROTSE-III optical counterpart position (H. Flewelling et al., GCN 9439). Upper limit for the observations is >20.2 mag (3UL). Quoted upper limit has been derived using POSSII F and USNO-B1.0 field stars as reference. Filter Tmid(s) Exp(s) Mag (CR) USNO-B1.0 u 05:55:15 4x600 19.2 A jpeg preview of the observation showing the position of the afterglow is at this URL: http://cutenews.kassiopeia.net/data/upimages/GRB090530.jpg //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9440 SUBJECT: GRB 090530: PAIRITEL NIR Detections DATE: 09/05/30 04:30:03 GMT FROM: Adam Morgan at U.C. Berkeley A. N. Morgan, D. A. Perley, J. S. Bloom, (UC Berkeley), and D. Starr (UCB, LCOGT) report: We observed the field of GRB 090530 (Cannizzo et al., GCN 9438) with the 1.3-m PAIRITEL located at Mt Hopkins, Arizona. Observations began at 2009-05-30 03:19:30 UT, 72 seconds after the Swift Trigger. We detect the optical afterglow (Cannizzo et al., GCN 9438, Flewelling et al., GCN 9439) in mosaics taken simultaneously in the J, H, and Ks filters. The preliminary photometry yields: post_burst t_mid (min) exp(s) filt mag merr 8.33 424 J 16.4 0.1 8.33 424 H 15.4 0.1 8.33 424 Ks 15.0 0.1 All magnitudes given in the Vega system, calibrated to 2MASS. No correction for Galactic extinction has been made to the above reported values. Observations are ongoing. [GCN OPS NOTE(30may09); The typo in the Subject line was changed from "090515" to "090530".] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9443 SUBJECT: GRB 090530: Swift-BAT refined analysis DATE: 09/05/30 12:34:07 GMT FROM: Scott Barthelmy at NASA/GSFC D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. K. Cannizzo (NASA/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), T. Sakamoto (GSFC/UMBC), 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-60 to T+243 sec from the recent telemetry downlink, we report further analysis of BAT GRB 090530 (trigger #353567) (Cannizzo, et al., GCN Circ. 9438). The BAT ground-calculated position is RA, Dec = 179.400, 26.590 deg, which is RA(J2000) = 11h 57m 36.0s Dec(J2000) = +26d 35' 23.0" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 41%. The mask-weighted light curve shows a FRED-like peak starting at ~T-0.3 sec, peaking at ~T+0.2 sec, and returning almost to background. Then a second and much smaller peak starts at ~T+35 sec, peaks at ~T+45 sec, and ends at ~T+50 sec. There is an ~3-sigma precursor peak at T-4sec. T90 (15-350 keV) is 48 +- 36 sec (estimated error including systematics). The time-averaged spectrum from T-12.2 to T+51.8 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.61 +- 0.17. The fluence in the 15-150 keV band is 1.1 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+0.0 sec in the 15-150 keV band is 2.5 +- 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/353567/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9445 SUBJECT: GRB 090530: Enhanced Swift-XRT position DATE: 09/05/30 15:15:48 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 646 s of XRT Photon Counting mode data and 1 UVOT images for GRB 090530, 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 = 179.41846, +26.59341 which is equivalent to: RA (J2000): 11h 57m 40.43s Dec (J2000): +26d 35' 36.3" with an uncertainty of 1.5 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: 9450 SUBJECT: GRB090530: Swift/UVOT afterglow detection DATE: 09/05/30 17:08:39 GMT FROM: Patricia Schady at MSSL/Swift P. Schady (MSSL-UCL) and J. K. Cannizzo (NASA/UMBC) report on behalf of the Swift UVOT team: The Swift/UVOT began settled observations of the field of GRB 090530 158s after the BAT trigger (Cannizzo et al., GCN Circ. 9438) and a decaying source is detected in all UVOT filters within the XRT error circle (Beardmore et al., GCN Circ. 9445), putting an upper limit on the redshift of z < 1.7. The source initially rises, and at around 100s after the BAT trigger decays at a constant rate of 0.73+/-0.03 for the duration of intial UVOT observations, out to ~20ks after the BAT trigger. The best UVOT position determined from a co-added white band exposure is RA (J2000) 11:57:40.50 = 179.41873 (deg) Dec (J2000) +26:35:38.4 = +26.59400 (deg) with an estimated uncertainty of 0.5 arcsec (radius, 90% confidence, statistical + systematic), consistent with the ROTSE-IIIb afterglow position (Flewelling et al., GCN Circ. 9439). The magnitudes for the observations currently available are as follows: Filter T_start(s) T_stop(s) Exp(s) Mag white 83 233 147 17.43 +/- 0.03 v 624 644 19 17.69 +/- 0.29 b 550 570 19 18.60 +/- 0.27 u 295 545 246 17.46 +/- 0.05 uvw1 5735 5935 197 20.15 +/- 0.37 uvm2 5530 11687 1082 20.31 +/- 0.22 uvw2 5121 17468 1279 21.31 +/- 0.32 The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998). The photometry is on the UVOT photometric system described in Poole et al. (2008, MNRAS, 383, 627). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9451 SUBJECT: GRB090530: Swift XRT refined analysis DATE: 09/05/30 21:09:24 GMT FROM: Vanessa Mangano at INAF-IASFPA Mangano V., Sbarufatti B. (INAF-IASFPA), J. K. Cannizzo (NASA/UMBC) report on behalf of the Swift XRT Team: We have analyzed the first five orbits of Swift-XRT data of GRB 090530 (trigger 353567; Cannizzo, et al., GCN Circ. 9438), consisting of 22 s in Windowed Timing (WT) mode from T+81 to T+103 s and 9 ks in Photon Counting (PC) mode from T+105 s to T+24.4 ks. The best position for the X-ray afterglow is the XRT UVOT-enhanced position: RA, Dec = 179.41846, +26.59341 which is equivalent to: RA (J2000): 11h 57m 40.43s Dec (J2000): +26d 35' 36.3" with an uncertainty of 1.5 arcsec (radius, 90% confidence), as given by Beardmore, et al., GCN Circ 9445. The 0.3-10 keV X-ray light curve is best fitted by a broken powerlaw with early decay index of about -5.7, late decay index -0.60+/-0.04 and a break at about 140 s after the trigger. In the first orbit a small amplitude flare is detected at T+300 s. Flaring activity is also visible along the later decay. If decaying at the present rate, the predicted rate after 24h from the trigger is 2.0e-2 counts/s. However, we remark that a second break followed by a steepening of the lightcurve is possibly expected. The issue will be clarified with following Swift observations that will resume on Sunday May 31st. The average initial WT spectrum (covering the initial steep decay) can be modeled as an absorbed power-law with index 2.3 (+0.5-0.4), absorbing column NH < 11E20 cm-2 (three sigma upper limit) and observed(unabsorbed) average flux in the 0.3-10 keV energy range of 2.9(3.6)E-10 ergs cm-2 s-1. The average PC spectrum (roughly covering the flatter part of the afterglow) is best fitted by an absorbed power-law with index 2.00+/-0.15 The absorbing column is NH = (8.2 -2.9+3.6)E20 cm-2 in excess with respect to the Galactic value of 1.78E+20 cm-2 (Kalberla et al. 2005). The average observed(unabsorbed) flux is 4.0(4.9)E-12 ergs cm-2 s-1. The count-rate to flux conversion factor is 5.4E-11. All quoted errors are at 90% confidence level. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00353567. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9452 SUBJECT: GRB 090530: NOT optical observations DATE: 09/05/30 23:26:56 GMT FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst D. Malesani, D. Xu, G. Leloudas, J.P.U. Fynbo (DARK/NBI), P. Jakobsson (Univ. Iceland), M.E. Brown (Caltech), E.L. Schaller (Univ. Hawaii), and T. Liimets (NOT & Tartu Obs.) report on behalf of a larger collaboration: We observed the field of GRB 090530 (Cannizzo et al., GCN 9438) with the NOT equipped with the MOSCA camera. Observations were carried out in the R band, starting on 2009 May 30.879 UT (17.8 hr after the GRB). The optical afterglow (Cannizzo et al., GCN 9438; Flewelling et al., GCN 9439; Morgan et al., GCN 9440) is clearly detected in a single 300s exposure, with a magnitude R = 21.6 assuming R = 18.17 for the USNO star at RA = 11:57:41.68, Dec = +26:35:43.3. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9458 SUBJECT: GRB 090530: break in light curve DATE: 09/05/31 12:36:48 GMT FROM: Jochen Greiner at MPI A. Rossi (Tautenburg), F. Olivares, and J. Greiner (both MPE Garching) report on behalf of the GROND team: We observed the field of GRB 090530 (Swift trigger 353567, Cannizzo et al., GCN #9438) simultaneously in g'r'i'z'JHK with GROND mounted at the 2.2m MPI/ESO telescope at La Silla Observatory (Chile). Observations started on 31 May 2009 at 00:36 UT, 21.3 h after the burst. We detect the optical/NIR afterglow (Cannizzo et al., GCN #9438; Flewelling et al., GCN #9439; Morgan et al., GCN #9440; Nissinen & Hentunen, GCN #9442) in stacked exposures of 20 min in JHK and 24 min in g'r'i'z'. Calibrating the r' band data against the USNO star at RA = 11:57:41.7, Dec = +26:35:43, we obtain R = (22.2 +-0.2) mag. Comparing this with the white light magnitudes obtained by ROTSE (Flewelling et al., GCN #9439), UVOT (Schady et al., GCN #9450) and GRAS002 (Nissinen & Hentunen, GCN #9442) as well as the NOT R-band magnitude (Malesani et al., GCN #9452), we find a break in the optical light at around 22 ksec post-burst (i.e. before the NOT observation), with slopes of 0.5+-0.1 (pre-break) and 1.8+-0.4 (post-break). We note that a break at this time is also visible in the Swift/XRT data (see repository; Evans et al. 2007). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9459 SUBJECT: GRB090530: R-band Observation DATE: 09/05/31 14:49:20 GMT FROM: Myungshin Im at Seoul Nat U M. Im (CEOU/Seoul National Univ) and Y. Urata (NCU) on behalf of EAFON team. We observed GRB090530 (Cannizzo et al. GCN 9438) in R using the 1.0m telescope at Mt. Lemmon (Arizona, US) operated by the Korea Astronomy Space Science Institute. The R-band imaging started at 2009 May 30, 04:18:02 UT (~1 hr after the burst), with the mid-point at May 30, 04:45 UT. In a stacked image of 9 frames (3 min exp. each), the optical afterglow is clearly detected at R=19.6 +- 0.15 mag. The photometry was calibrated against R2mag of USNO-B1 stars in the vicinity of GRB. We thank the LOAO operator, J. Yoon for his assistance for this observation. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9466 SUBJECT: GRB 090530: GRT Optical Observation DATE: 09/06/01 01:50:08 GMT FROM: Takanori Sakamoto at NASA/GSFC T. Sakamoto (UMBC/GSFC), D. Donato (ORAU/GSFC), N. Gehrels (GSFC), T. Okajima (JHU/GSFC), T. N. Ukwatta (GWU/GSFC), Y. Urata (NCU), C. Wallace (FGCU) We observed the field of GRB 090530 detected by Swift (trigger #353567; Cannizzo et al., GCN #9438) with the 14-inch Goddard Robotic Telescope (GRT) located at the Goddard Geophysical and Astronomical Observatory (http://cddisa.gsfc.nasa.gov/ggao/). 100 set of 30 sec exposures were taken in the R filter starting from May 30 03:33:00 (UT) about 15 min after the trigger and stopped on May 30 04:29:30 (UT). We do not detect the optical afterglow (Cannizzo et al., GCN #9438, Flewelling et al., GCN #9439, Nissinen et al., GCN #9441, Malesani et al., GCN #9452, Im et al., GCN #9459) both in the individual images and the combined image. The estimated three sigma upper limit of the combined image (total exposure of 3000 sec) is ~18.1 mag using the USNO-B1 catalog. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9472 SUBJECT: GRB 090530B: Fermi GBM detection DATE: 09/06/01 14:56:31 GMT FROM: Alexander van der Horst at NASA/MSFC A.J. van der Horst (NASA/MSFC/ORAU) reports on behalf of the Fermi GBM Team: "At 18:14:24.42 UT on 30 May 2009, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 090530B (trigger 265400066 / 090530.760). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 73.2, Dec = +13.8 (J2000 degrees, equivalent to J2000 4h53m, +13d47'), with a statistical uncertainty of less than 1 degree (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). The angle from the Fermi LAT boresight is 84 degrees. The GBM light curve of this long and soft GRB consists of a double peaked FRED, with a total duration (T90) of 194 s (8-1000 keV). The time-averaged spectrum from T0-3.1 to T0+110.6 s is best fit by a Band function with alpha = -0.71 +/- 0.06, beta = -2.42 +/- 0.05, and Epeak = 67 +/- 3. The fluence (8-1000 keV) in this interval is (5.9 +/- 0.4)E-5 erg/cm^2. The 1-sec peak photon flux measured starting from T0+10.2s in the 8-1000 keV band is 10.8 +/- 2.0 ph/s/cm^2. The spectral and temporal analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9478 SUBJECT: GRB 090530: Early RAPTOR Optical Observations DATE: 09/06/02 00:37:08 GMT FROM: James Wren at LANL J. Wren, W.T. Vestrand, P.R. Wozniak, H. Davis, B. Norman of Los Alamos National Laboratory report: The RAPTOR telescope system responded to Swift trigger 353567 (Cannizzo et al., GCN 9438) under fair observing conditions. Our narrow-field instruments began observing the location at 03:18:37.96 UTC, 19.6 s after the Swift trigger. We detect the optical counterpart initially reported by Cannizzo et al. (GCN 9438) and Flewelling et al. (GCN 9439). Our first image at T+22.1 seconds shows the counterpart at R~17.1. It appears to brighten over the next minute reaching a peak near R~16.3 and then begins fading in the manner described by Schady et al. (GCN 9450) and Rossi et al. (GCN 9458). Our unfiltered images were calibrated against the USNO-B1 R-band. The following table gives selected observations, not corrected for extinction, from this event. t-mid(s) exp(s) mag mag-err -------------------------------------------- 22.08 5.0 17.13 0.25 57.90 5.0 16.30 0.10 84.50 5.0 16.60 0.13 133.21 10.0 16.87 0.11 414.65 30.0 17.31 0.09 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9487 SUBJECT: GRB 090530: RTT150 Optical Observation DATE: 09/06/03 17:47:25 GMT FROM: Solen Balman at METU S. Balman (METU), M. Parmaksizoglu (TUG) Z. Eker (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.) I. Bikmaev, N. Sakhibullin (KSU/AST) R. Burenin, M. Pavlinsky, R. Sunyaev (IKI), report: We observed the field of GRB 090530 (Swift trigger=353567, Cannizzo et al.,2009 GCN Circ. 9438) with the Russian-Turkish 1.5-m telescope (RTT150, Bakirlitepe, TUBITAK National Observatory, Turkey) on 30 May starting at 18:30:37.7 UT about 15.2 hours (0.633 d) after the burst using the TFOSC CCD (burst detected at 03:18:18 UT with Swift Burst Alert Telescope(BAT)). Flewelling et al. 2009 GCN Circ. 9439 found the afterglow at 16.0 mag at 03:18:42.7 UT. Calibrating the data against the USNO star at RA = 11:57:41.7, Dec = +26:35:43, Rossi et al. 2009 GCN Circ. 9458 obtain R = (22.2 +-0.2) mag 21.3 hrs after burst. They also found a break in the optical light at around 22 ksec post-burst (see also GCN Circ.9440-9443, 9450-9452, 959, 9466, 9478 for white light and UV photometry). We obtained one 900 sec exposure using the R band filter (Bessell filter). We used the Swift XRT position derived by Breadmore at al. (2009) GCN Circ. 9445 to locate the afterglow candidate. We were able see the source, but unable to calculate a magnitude using PSF photometry with DAOPHOT within MIDAS software performed on the 13.3 by 13.3 arcmin field around the candidate. We find a frame upper limit of R = 21.1+/-0.5 mag at 3 sigma and 21.9+/-0.5 mag at 2 sigma confidence level calculated using the same USNO star mentioned in the above paragraph. This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9488 SUBJECT: GRB 090530: Further NOT optical observations DATE: 09/06/03 19:51:39 GMT FROM: Dong Xu at DARK,NBI D. Xu, G. Leloudas, D. Malesani, J. P. U. Fynbo, J. Hjorth (DARK/NBI), P. Jakobsson (Univ. Iceland), and T. Liimets (NOT & Tartu Obs.) report on behalf of a larger collaboration: We continued to observe the field of GRB 090530 (Cannizzo et al., GCN 9438) with the Nordic Optical Telescope equipped with ALFOSC. We obtained 3x600 s R-band frames staring on June 01, 22:04:19 UT, 66.7669 hr after the burst. The optical afterglow (Cannizzo et al., GCN 9438) is still detected in the stacked frame. The magnitude is R=22.6+/-0.2 against the same reference star in Malesani et al. (GCN 9452). Balman et al. (GCN 9487) found a 3sigma upper limit of R=21.1+/-0.5 mag at 15.2 hr after the burst. Our first observation shows R=21.6 mag at 17.8 hr after the burst. Rossi et al. (GCN 9458) found R=22.2+/-0.2 mag at 21.3 hr after the burst, and a break in the light curve at around 22 ksec post-burst with slopes of 0.5+-0.1 (pre-break) and 1.8+-0.4 (post-break), using previous obs (Flewelling et al., GCN 9439; Schady et al., GCN 9450; Nissinen & Hentunen, GCN 9442). Our new observation indicates that the optical decay is becoming much slower. The slower optical decay may be due to the presence of a fairly bright host galaxy. Further optical observations are encouraged. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9489 SUBJECT: GRB 090530B: Suzaku WAM observation of the prompt emission DATE: 09/06/04 11:05:56 GMT FROM: Kazuhiro Noda at Miyazaki U K. Noda, E. Sonoda, M. Yamauchi, N. Ohmori, H. Hayashi, K. Kono, A. Daikyuji, Y. Nishioka (Univ. of Miyazaki), Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa (Hiroshima U.), M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA), W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda, T. Sugasahara (Saitama U.), Y. Urata (NCU), T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo), K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y. E. Nakagawa, T. Tamagawa (RIKEN), S. Hong (Nihon U.), N. Vasquez (Tokyo Tech.), on behalf of the Suzaku WAM team, report: The long GRB 090530B (Fermi/GBM trigger #265400066 / 090530.760; van der Horst et al., GCN 9472) was detected by the the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 18:14:23 UT (=T0). The observed light curve shows a single peak starting at T0-1s, ending at T0+219s, with a duration (T90) of about 113 seconds. The fluence in 100 - 1000 keV was 2.41 ( +0.06/ -0.07 )x10-5 erg/cm2. The 1-s peak flux measured from T0+8s was 2.39 ( +0.08/ -1.41 ) photons/cm2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0-1s to T0+219s is well fitted by a single power-law with a photon index of 3.30 ( +0.14/ -0.13 ) (chi2/d.o.f = 31/17 ). All the quoted errors are at statistical 90% confidence level, in which the systematic uncertainties are not included. The light curves with 1-sec time resolution for this burst will be appeared at: http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10015 SUBJECT: GRB 090530A: Skynet/DSO Detections DATE: 09/10/11 21:25:05 GMT FROM: Aaron LaCluyze at U.North Carolina A. Smith, A. LaCluyze, D. Reichart, D. Caton, L. Hawkins, J. Haislip, K. Ivarsen, A. Foster, J. Moore, A. Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. Nysewander report: Skynet observed the Swift/BAT localization of GRB 090530A (Cannizzo et al., GCN 9438) with the 14" Dark Sky Observatory telescope in North Carolina beginning 61.8 minutes after the trigger in RI. We detect the afterglow (Cannizzo et al., GCN 9438). Stacking only images that increase the limiting magnitude yields: mean 1-sig. 1-sig. time sys. stat. since cal. cal. cal. trig. tel. exp. fil. magnitude stars* unc. unc. (m) (# x s) (mag) (mag) 88.8 DSO-14 20 x 80 I 19.26 +0.32 -0.25 7 SDSS 7 0.050 0.001 102.2 DSO-14 23 x 80 R 19.53 +0.16 -0.14 10 SDSS 7 0.022 0.001 * Transformed using Jester et al., 2005, ApJ, 130, 873. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15571 SUBJECT: GRB 090530: X-shooter redshift DATE: 13/12/03 18:31:28 GMT FROM: Paolo Goldoni at U.Paris/APC P. Goldoni (APC/Irfu - CEA), A. de Ugarte Postigo (IAA - CSIC and DARK/NBI) and J.P.U. Fynbo (DARK/NBI) report on behalf of the X-shooter GRB collaboration : We reduced with the most recent pipeline the observations of the optical afterglow of GRB 090530 (Cannizzo et al., GCN 9438) made using the ESO VLT equipped with the X-shooter spectrograph. The observations were performed during commissioning with the instrument not fully calibrated. The observations started on 2009-05-30 at 23:56 UT (i.e., 20.63 hr after the burst). A total exposure of 1x900 s + 4x1200 s was obtained, covering the spectral range from ~3000 to ~24000 Ang. The afterglow is detected in the UVB and VIS arms with a faint continuum. Superposed on the continuum we detected spectral features consistent with MgII, MgI, SiII, FeII and AlIII at a redshift ~1.266 fully consistent with the photometric redshift 1.28 (+0.16, -0.15) (Kruehler et al. 2011, A&A 526, 153).