//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 22710 SUBJECT: GRB 180512A: Swift detection of a burst DATE: 18/05/12 23:01:48 GMT FROM: Alex Deich at Penn State U A. Deich (PSU), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), J.D. Gropp (PSU), S. J. LaPorte (PSU), A. Y. Lien (GSFC/UMBC) and F. E. Marshall (NASA/GSFC) report on behalf of the Neil Gehrels Swift Observatory Team: At 22:01:47 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 180512A (trigger=832119). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 201.953, +21.406 which is RA(J2000) = 13h 27m 49s Dec(J2000) = +21d 24' 23" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 550 sec. The main pulse starts at ~T+400 s and ends at ~T+550 s. The peak count rate was ~1000 counts/sec (15-350 keV), at ~500 sec after the trigger. The XRT began observing the field at 22:05:20.1 UT, 213.0 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 201.93846, 21.40271 which is equivalent to: RA(J2000) = 13h 27m 45.23s Dec(J2000) = +21d 24' 09.8" with an uncertainty of 4.4 arcseconds (radius, 90% containment). This location is 50 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. We cannot determine whether the source is fading at the present time. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 1.73 x 10^20 cm^-2 (Willingale et al. 2013). No UVOT data are available at this time. Burst Advocate for this burst is A. Deich (aud375 AT psu.edu). 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: 22711 SUBJECT: GRB 180512A: Upper limits from OSN DATE: 18/05/12 23:37:11 GMT FROM: Alexander Kann at IAA-CSIC A. de Ugarte Postigo (HETH/IAA-CSIC, Dark/NBI), L. Izzo, D. A. Kann (both HETH/IAA-CSIC), and A. Sota (IAA/CSIC) report on behalf of HETH: We observed the field of GRB 180512A (Deich et al.; GCN Circ. 22710) with the 1.5-m OSN telescope in Granada, Spain Observations started at 22:15:35 UT (827 s after the GRB trigger) for OSN, and we obtained 8x60s images in the Rc band and 6x300s images in the Ic band. Observations were obtained in inclement conditions (bad seeing of ~3"). In our stacked images, we find no source inside the Swift-XRT error circle down to a 3-sigma limit of Ic (Vega) > 21. The calibration was performed using nearby stars in the SDSS catalog. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 22712 SUBJECT: GRB 180512A: OASDG optical observations DATE: 18/05/12 23:39:22 GMT FROM: Luca Izzo at IAA-CSIC L. Izzo (HETH/IAA-CSIC) reports: We observed the field of GRB 180512A (Deich et al., GCN Circ. 22710) with the 0.5m telescope of the Osservatorio Astronomico S. Di Giacomo located in Agerola, Italy ( http://acgo.it/oa ) We began observing at 22:31:54 UT (~30 min after the GRB trigger), and obtained 7x180s images in the Rc band. In our stacked image, we find no source inside the Swift-XRT error box down to a 3-sigma limit of Rc (Vega) > 20.2. The calibration was performed using nearby stars in the USNO B1 catalog. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 22713 SUBJECT: GRB 180512A: NOT upper limits DATE: 18/05/13 00:15:15 GMT FROM: Kasper Elm Heintz at Univ. of Iceland and DAWN/NBI Kasper Elm Heintz (Univ. Iceland and DAWN/NBI), Daniele Malesani (DAWN/NBI and DARK/NBI), Lauri Siltala (NOT), and Pilar Montanes Rodriguez (IAC), report on behalf of a larger collaboration: We observed the field around GRB 180512A (Deich et al., GCN 22710) with the 2.5-m Nordic Optical Telescope (NOT) equipped with ALFOSC. Observations of 3x100 s were carried out in each of the SDSS r, i, and z filters and started at 22:48:54 UT on May 12, 47 min after trigger. We do not detect the optical counterpart within the Swift-XRT error circle and calibrated against Pan-STARRS local photometry we measure upper limits (at 3-sigma) of: m(r) > 23.3, m(i) > 23.0, and m(z) > 22.1 AB mag. These magnitudes are not corrected for Galactic extinction in the direction of the GRB. [GCN OPS NOTE(12may18): Per author's request, a typo in the author name Rodriguez was corrected.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 22714 SUBJECT: GRB 180512A: GROND upper limits DATE: 18/05/13 02:42:32 GMT FROM: Jan Bolmer at MPE/Garching J. Bolmer MPE Garching) reports on behalf of the GROND Team: I observed the field of GRB180512A (Swift trigger 832119; Deich et al., GCN #22710) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPG telescope at the ESO La Silla Observatory (Chile). Observations started at 00:03 UT on 2018-05-13, 2.7 hrs after the GRB trigger. They were performed at an average seeing of 1.3'' and at an average airmass of 1.9. No source is detected within or close to the Swift-XRT error circle. Based on 40 min of exposure in g'r'i'z' and 41 min in JHK_s, at a mid-time of 00:44 UT, we derive the following preliminary upper limits (in AB system): g' > 25.4 mag, r' > 24.9 mag, i' > 24.0 mag, z' > 23.4 mag, J > 21.9 mag, H > 21.2 mag, and K_s > 20.2 mag. Given upper limits are calibrated against SDSS field stars in g'r'i'z' as well as 2MASS field stars in JHK_s. No correction for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.058 mag in the direction of the burst (Schlafly & Finkbeiner 2011) has been applied. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 22715 SUBJECT: GRB 180512A: Enhanced Swift-XRT position DATE: 18/05/13 04:49:52 GMT FROM: Phil Evans at U of Leicester P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team. Using 1368 s of XRT Photon Counting mode data and 4 UVOT images for GRB 180512A, 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 = 201.93805, +21.40355 which is equivalent to: RA (J2000): 13h 27m 45.13s Dec (J2000): +21d 24' 12.8" with an uncertainty of 1.9 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, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 22716 SUBJECT: GRB 180512A: LT prompt observations DATE: 18/05/13 08:31:12 GMT FROM: Cristiano Guidorzi at Ferrara U,Italy C. Guidorzi, R. Martone (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell (U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU) on behalf of a large collaboration report: The 2-m Liverpool Telescope automatically began observing Swift GRB 180512A (Deich et al. GCN 22710) on May 12, 22:07:15 UT (5.5 minutes since the GRB) with the RINGO3 polarimeter and the IO:O camera in the SDSS-R filter. Within the enhanced XRT error circle (Evans et al. GCN 22715) we do not detect any optical counterpart down to the following magnitude: Mid time since GRB     Exp        Filter         Magnitude (hrs)                  (s) ----------------------------------------------------------- 0.64                  6x10       SDSS-R          > 20.8 ----------------------------------------------------------- as calibrated against nearby SDSS objects. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 22717 SUBJECT: GRB 180512A: Swift/UVOT Upper Limits DATE: 18/05/13 10:53:43 GMT FROM: Paul Kuin at MSSL N. P. M. Kuin (UCL-MSSL) and Deich (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 180512A 218 s after the BAT trigger (Deich et al., GCN Circ. 22710). No optical afterglow consistent with the XRT position (Evans et al. GCN Circ. 22715) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 218 368 147 >21.1 white 218 4358 344 >21.2 v 5986 6120 132 >19.0 b 3953 4153 197 >20.7 u 3748 16254 422 >20.7 w1 3543 16019 1107 >20.3 m2 9380 10280 886 >20.9 w2 5781 5981 197 >20.1 The magnitudes in the table 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). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 22718 SUBJECT: GRB 180512A: LBT optical detection DATE: 18/05/13 13:13:01 GMT FROM: Andrea Rossi at INAF A. Rossi and E. Palazzi (INAF-OAS) report on behalf of the CIBO colaboration: We observed the field of GRB180512A (Swift trigger 832119; Deich et al., GCN #22710) simultaneously in r' and z' bands with the LBC imager mounted on LBT (Mt Graham, AZ, USA). Observations started at 04:05 UT on 2018-05-13, 6 hrs after the GRB trigger and finished at 04:27 UT and allowed us to obtain 20min of exposure in each band. Image inspection reveals a faint source within the Swift/XRT enhanced error circle (Evans et al., GCN 22715) with coordinates: RA(J2000) = 13:27:45.130 Dec(J2000)= +21:24:13.39 with an uncertainty of 0.2" in each coordinate. The source is detected only r'-band and has magnitude r' = 25.0 mag +-0.3 (AB), calibrated against r'-band SDSS field stars. No statement about the variability can be made at this point. Further observations are planned. No correction for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.02 mag in the direction of the burst (Schlafly & Finkbeiner 2011) has been applied. We acknowledge the excellent support from the LBT-INAF staff, particularly F. Cusano and A. Gargiulo in obtaining these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 22719 SUBJECT: GRB 180512A: RATIR Optical Observations DATE: 18/05/13 16:00:35 GMT FROM: Alan M. Watson at Instituto de Astronomia UNAM Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki Toy (UMD) report: We observed the field of GRB 180512A (Deich et al., GCN Circ. 22710) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir from 2018/05 13.16 to 2018/05 13.44 UTC (5.75 to 12.58 hours after the BAT trigger), obtaining a total of 5.22 hours exposure in the r and i bands. For a source within the enhanced Swift-XRT error circle (Evans et al., GCN Circ. 22715), in comparison with the SDSS DR9 and 2MASS catalogs, we obtain the following 3-sigma upper limits: r > 24.30 i > 24.23 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 22720 SUBJECT: GRB 180512A: Swift-BAT refined analysis DATE: 18/05/13 16:56:18 GMT FROM: Amy Lien at GSFC J. R. Cummings (CPI), S. D. Barthelmy (GSFC), A. Deich (PSU), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 180512A (trigger #832119) (Deich et al., GCN Circ. 22710). The BAT ground-calculated position is RA, Dec = 201.940, 21.404 deg which is RA(J2000) = 13h 27m 45.5s Dec(J2000) = +21d 24' 15.7" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 67%. The mask-weighted light curve shows a weak pulse that starts at ~T+30 s, peaks at ~T+40 s, and ends at ~T+55 s. The short spike at T+54.4 s is due to detector noise. T90 (15-350 keV) is 24.0 +- 7.1 sec (estimated error including systematics). Note that the burst went out of the BAT FOV at T+469 s. The large pulse seen in the BAT raw light curve from ~T+400 s to ~T+550 s was from a bright background source that came in and out of the BAT FOV during this time interval. The time-averaged spectrum from T+29.00 to T+55.00 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.10 +- 0.27. The fluence in the 15-150 keV band is 4.2 +- 0.7 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+39.00 sec in the 15-150 keV band is 0.6 +- 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/832119/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 22721 SUBJECT: GRB 180512A: Swift-XRT refined Analysis DATE: 18/05/13 22:27:02 GMT FROM: Phil Evans at U of Leicester D.N. Burrows (PSU), A. Tohuvavohu (PSU), S.L. Gibson (U. Leicester), Z. Liu (NAOC / U. Leicester), J.P. Osborne (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), S. J. LaPorte (PSU) and A. Deich report on behalf of the Swift-XRT team: We have analysed 4.2 ks of XRT data for GRB 180512A (Deich et al. GCN Circ. 22710), from 230 s to 72.7 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN Circ. 22715). The light curve can be modelled with a power-law decay with a decay index of alpha=0.87 (+0.12, -0.11). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.5 (+0.9, -0.8). The best-fitting absorption column is 2.3 (+1.5, -1.1) x 10^22 cm^-2, in excess of the Galactic value of 1.7 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 5.2 x 10^-11 (1.9 x 10^-10) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 2.3 (+1.5, -1.1) x 10^22 cm^-2 Galactic foreground: 1.7 x 10^20 cm^-2 Excess significance: 3.6 sigma Photon index: 2.5 (+0.9, -0.8) If the light curve continues to decay with a power-law decay index of 0.87, the count rate at T+24 hours will be 2.1 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x 10^-13 (4.0 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00832119. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 22724 SUBJECT: GRB 180512A: VLT/HAWK-I NIR Observations DATE: 18/05/14 15:28:16 GMT FROM: Andrea Rossi at INAF A. Rossi (INAF-OAS), J. Palmerio (IAP, Paris), J. Japelj (API, U. Amsterdam), D. Malesani (DAWN/NBI and DARK/NBI), N. R. Tanvir (Univ. Leicester), D. A. Kann (HETH/IAA-CSIC), J. P. U. Fynbo (DAWN/NBI), G. Pugliese (API, U. Amsterdam), A. de Ugarte Postigo (HETH/IAA-CSIC and DARK/NBI), K. E. Heintz (Univ. Iceland and DAWN/NBI), and S. D. Vergani (GEPI/Obs. Paris) report on behalf of the Stargate Consortium: We observed the Swift/XRT afterglow localization of GRB 180512A (Swift trigger 832119; Deich et al., GCN #22710) with the ESO VLT UT4 equipped with the HAWK-I near-infrared imager. Observations started on 2018 May 13 at 04:27 UT and ended at 05:28 UT, for a total of 36 min on source and corresponding to a midtime of ~7 hours after the GRB trigger. We do not detect the optical source observed by Rossi et al. (GCN #22718), nor any other object within the XRT error circle, down to H > 22.8 (Vega), calibrated against 2MASS field stars. Moreover, we note that after comparing the early GROND upper limit (r' > 24.9; Bolmer, GCN #22714) with the Swift/XRT observations, we obtain an optical to X-ray spectral slope beta_OX < ~0.1 (using the convention F_nu ~ nu^-beta). This value is lower than the minimum expected following standard afterglow modelling (beta_OX >= 0.5) and, together with the r-band detection with LBT as well as the high X-ray column density (Burrows et al., GCN #22721), suggests that a combination of moderate redshift, intrinsic faintness and dust extinction is responsible for the faint optical afterglow. We acknowledge the excellent support from the ESO staff, particularly Cyrielle Opitom, Fuyan Bian, and Steffen Mieske in obtaining these observations.