//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17688 SUBJECT: GRB 150413A: Swift detection of a burst DATE: 15/04/13 14:06:39 GMT FROM: David Palmer at LANL C. B. Markwardt (NASA/GSFC), M. M. Chester (PSU), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), C. Pagani (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL) and T. N. Ukwatta (LANL) report on behalf of the Swift Team: At 13:54:58 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 150413A (trigger=637899). Swift did not slew immediately to the burst due to an observing constraint. The BAT on-board calculated location is RA, Dec 190.385, +71.824 which is RA(J2000) = 12h 41m 32s Dec(J2000) = +71d 49' 26" 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 120 sec. The peak count rate was ~1100 counts/sec (15-350 keV), at ~2 sec after the trigger. Due to an observing constraint, Swift cannot observe until T0+4 days. There will be no XRT or UVOT data until this time. Burst Advocate for this burst is C. B. Markwardt (Craig.Markwardt AT 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: 17689 SUBJECT: GRB 150413A: MASTER bright OT detection DATE: 15/04/13 14:21:11 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University E. Gorbovskoy, V. Lipunov, N.Tyurina, V.Kornilov, P.Balanutsa, A.Kuznetsov, D.Kuvshinov, Lomonosov Moscow State University, Sternberg Astronomical Institute D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk V.Krushinski, I.Zalozhnih, A. Popov Ural Federal University, Kourovka Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Tunka was pointed to the GRB150413A (Markwardt et al. GCN 17688) 132 sec after trigger time at 2015-04-13 13:57:10 UT in two polarizations. We see bright OT at: RA, Dec = 12 41 41.98 +71 50 28.0 Mag = 16.1 (unfiltered 0.2B +0.8R UsnoB1) The discovery image is available at https://master.sai.msu.ru/static/OT/grb150413A.jpg The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17690 SUBJECT: GRB 150413A: MASTER very bright unusual OT observations DATE: 15/04/13 14:46:33 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs N.Tyurina, E. Gorbovskoy, N.Tyurina, V.Kornilov, P.Balanutsa, A.Kuznetsov, D.Kuvshinov, Lomonosov Moscow State University, Sternberg Astronomical Institute K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk V.Krushinski, I.Zalozhnih, A. Popov Ural Federal University, Kourovka Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Tunka was pointed to the GRB150413A (Markwardt et al. GCN 17688) 132 s. After MASTER OT J124141.98+715028.0 detection (Ivanov et all, GCN 17689) we see obvious brightening on next 4 expozition sets in two polarizations. After 18 min MASTER OT J124141.98+715028.0 is about 14.7 ! The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17691 SUBJECT: GRB 150413A: MAXI/GSC detection DATE: 15/04/13 15:09:31 GMT FROM: Motoko Suzuki at RIKEN M. Serino (RIKEN), H. Negoro (Nihon U.), S. Nakahira (JAXA), S. Ueno, H. Tomida, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Shidatsu, J. Sugimoto, T. Takagi, M. Matsuoka (RIKEN), N. Kawai, T. Yoshii, Y. Tachibana (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, R. Imatani (Osaka U.), M. Nakajima, T. Namba, M. Fujita, F. Honda, K. Tanaka, T. Masumitsu (Nihon U.), Y. Ueda, T. Kawamuro, T. Hori (Kyoto U.), Y. Tsuboi, S. Kanetou (Chuo U.), M. Yamauchi, D. Itoh (Miyazaki U.), K. Yamaoka (Nagoya U.), M. Morii (ISM) report on behalf of the MAXI team: At 13:56:30 UT, the MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at the position (R.A., Dec) = (190.278 deg, 71.742 deg) = (12 41 07, +71 44 31) (J2000). The position is consistent with that reported by Markwardt et al. (GCN 17688). The X-ray flux averaged over the scan was 440 +- 40 mCrab (4-10keV, 1 sigma error). There was no significant excess flux in the previous transit at UT 12:24 with an upper limit of 20 mCrab. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17692 SUBJECT: GRB 150413A: Khureltogot optical observations DATE: 15/04/13 15:55:04 GMT FROM: Alexei Pozanenko at IKI, Moscow S. Schmalz (AIP), A. Pozanenko (IKI), N. Tungalag (Research Center of Astronomy and Geophysics MAS), E. Mazaeva (IKI), A. Volnova (IKI), I.Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of the GRB 150413A (Markwardt et al., GCN 17688; Serino et al., GCN 17691) with ORI-40 telescope of Khureltogot observatory starting on Apr., 13 (UT) 14:08:52, i.e. ~10 minutes after burst trigger. Within BAT/Swift error circle we clearly detect fading optical source (Ivanov et al. GCN 17689, Tyurina et al. GCN 17690). Preliminary photometry of the source in single images is following Date UT start t-T0 Filter Exp. OT OT_err (mid, days) (s) 2015-04-13 14:08:52 0.0069 none 60 14.7 0.1 2015-04-13 14:39:52 0.0318 none 60 15.6 0.1 2015-04-13 15:11:54 0.0541 none 60 16.3 0.1 Photometry is based on nearby USNO-B1.0 stars, R2 mags. Observation is continuing. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17693 SUBJECT: GRB 150413A: Nanshan optical and radio follow-ups DATE: 15/04/13 16:14:57 GMT FROM: Dong Xu at NAOC/CAS D. Xu (NAOC), X. Zhang, C.-H. Bai, G.-J. Feng, A. Esamdin, L. Ma, J.-Z. Liu (XAO), Y. Qin (Geneva Observatory), J.-P. Yuan, Z.-G. Wen (XAO) report: We observed the field of GRB 150413A (Markwardt et al., GCN 17688; Serino et al., GCN 17691) using the 1m telescope located at Nanshan, Xinjiang, China. Observations started at 15:00:38 UT on 2015-04-13, i.e., 1.09 hr after the burst and a series of 150s R-band images were obtained and observations are ongoing. The OT reported by MASTER (Ivanov et al., GCN 17689; Tyurina et al., GCN 17690) is within the BAT error circle, and it is clearly detected in each of our images. Preliminary reduction shows that the OT has been decaying very slowly since our observations. It has m(R) ~ 15.4 at 1.115 hr post-burst and has m(R) ~ 15.8 at 1.724 hr post-burst, calibrated with the same USNO B1 star (#1618-0098185, R=15.59, close to R1=16.02). The OT's lightcurve behavior is unusual compared to normal GRB optical afterglows, although it indeed could be the afterglow of the GRB. We note that there is a bright and much extended galaxy within the BAT error circle. However, we didn't find any apparent new point source within the galaxy, compared to DSS. In addition, we observed the field using the Nanshan 25m radio dish in the pulsar searching mode, to check if there is any radio pulse mimicking a fast radio burst and following the BAT trigger. [GCN OPS NOTE(21apr15): Per author's request, the mode in the last sentence was changed from "timing mode" to "pulsar searching mode".] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17694 SUBJECT: GRB 150413A: Tautenburg observations DATE: 15/04/13 19:50:02 GMT FROM: Sylvio Klose at TLS Tautenburg S. Klose, S. Schmidl, B. Stecklum, A. Nicuesa Guelbenzu, D. A. Kann, and F. Ludwig (TLS Tautenburg) report: Tautenburg observed the afterglow of GRB 150413A (Markwardt et al., GCN 17688; Ivanov et al., GCN 17689; Tyurina et al., GCN 17690; Serino et al., GCN 17691; Schmalz et al., GCN 17692; Xu et al., GCN 17693) with the 1.34m Schmidt telescope under good weather conditions. At a mean time of 19:23 UT we measure a preliminary magnitude of R = 17.2 +/- 0.1, calibrated against the USNO B1 star #1618-0098185 (Xu et al.). Observations are continuing. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17695 SUBJECT: GRB 150413A: Khureltogot optical observations DATE: 15/04/14 02:02:12 GMT FROM: Alexei Pozanenko at IKI, Moscow S. Schmalz (AIP), N. Tungalag (Research Center of Astronomy and Geophysics MAS), A. Pozanenko (IKI), E. Mazaeva (IKI), A. Volnova (IKI), I. Molotov (KIAM), report on behalf of larger GRB follow-up collaboration: We observed the field of the GRB 150413A (Markwardt et al., GCN 17688; Serino et al., GCN 17691) with ORI-40 telescope of Khureltogot observatory starting on Apr., 13 (UT) 14:08:52 and finishing on Apr. 13 (UT) 20:08:39. The afterglow (Ivanov et al., GCN 17689, Tyurina et al., GCN 17690, Schmalz et al., GCN 17692, Xu et al., GCN 17693, Klose et al., GCN 17694) is detected up to the end of our observations. Preliminary light curve obtained for single unfiltered images and calibrated against nearby USNO-B1.0 stars (R2 mags) can be found in http://grb.rssi.ru/GRB150413A/GRB150413A_ORI40_lc.jpg In particular, our photometry on Apr., 13 (UT) 19:21:35 R=17.2+/-0.1 is compatible with photometry at (UT) 19:23 reported by Klose et al. (GCN 17694). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17696 SUBJECT: GRB 150413A: P60 photometry DATE: 15/04/14 04:41:01 GMT FROM: Daniel Perley at Caltech D. A. Perley (Caltech) and S. B. Cenko (GSFC) report: The Palomar 60-inch telescope observed the location of the optical counterpart of GRB 150413A (Markwardt et al., GCN 17688; Ivanov et al., GCN 17689) starting at 03:15:21 UT on 2015-04-14. We acquired 3x180s images in griz filters under good conditions. The optical transient is well-detected in all four filters. Calibrating relative to USNO stars in the field, we measure a magnitude of R = 19.1 (+/- 0.1) mag at this time (t = 0.560 days after the BAT trigger), indicating significant fading since the early observations. Further follow-up is planned. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17697 SUBJECT: GRB 150413A: redshift determination with the 2.2m CAHA DATE: 15/04/14 10:34:25 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia R. Sanchez-Ramirez (UPV/EHU, IAA-CSIC), A. J. Castro-Tirado (IAA-CSIC, ISA-UMA), F. Hoyos and J. Aceituno (CAHA), on behalf of a larger collaboration, report: Following the detection of GRB 150413A by Swift (Markwardt et al. GCNC 17688) we have obtained a 1200s+1800s spectrum at the position of the optical afterglow (Ivanov et al. GCNC 17689, Serino et al. GCNC 17691, Schmalz et al. GCNC 17692, Xu et al. GCNC 17693, Klose et al. GCNC 17694). Observations were carried out with the 2.2m CAHA telescope (+ CAFOS) at the German-Spanish Calar Alto Observatory, starting at 20:25 UT. (i.e. 6.5 hr post-burst) under poor weather and seeing conditions. After a preliminary reduction, we have detected a broad absorption line which we identify as Lyman-alpha at a reshift of z = 3.2. Due the low SNR of the combined spectrum, we only detect several lines at low significance (Ni II, Si IV, C IV, Fe II,…) consistent with this redshift, which we propose to be the redshift of GRB 150413A. We acknowledge excellent support of the CAHA staff. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17698 SUBJECT: GRB 150413A: optical observations DATE: 15/04/14 12:12:40 GMT FROM: Klaas Wiersema at U Leicester I. van de Stadt (AWSV Metius, Alkmaar, The Netherlands) and K. Wiersema (U. of Leicester) report: We observed the field of GRB 150413A (Markwardt et al. GCN 17688; Ivanov et al., GCN 17689) using the ABT, a 10-inch remote controlled observatory in Alkmaar, The Netherlands. In a series of I band exposures, with midpoint 0.55 days after burst, the afterglow is not detected, with a 5-sigma upper limit of 18.7 mag (calibrated using APASS field stars and the Jordi et al. (2005) conversions). This limit is in agreement with the light curve break seen by Schmalz et al. (GCN 17695). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17700 SUBJECT: GRB150413A, optical observations DATE: 15/04/14 13:57:16 GMT FROM: Kosmas Gazeas at U of Athens Kosmas Gazeas and Konstantinos Sapountzis (National Univ. of Athens) report: On 13 April 2015, we observed the GRB candidate optical counterpart GRB150413A, as reported by Markwardt et al., GCN 17688 and Serino et al., GCN 17691. The observations have been obtained with the 0.40 m f/8 robotic telescope at the University of Athens in R-band (Bessell specifications). Data collection has started on Apr., 13 (UT) 17:38:58 and finishing on Apr. 13 (UT) 18:08:08 (mid-exposure time). A sum of 15 exposures of 120 sec each was collected and all data were combined into a single image, although the optical afterglow was barley seen in each individual exposure. Photometry with a 3 pixel (approximately 4 arcsec) radius aperture yields an R magnitude estimation of R = 17.9 +- 0.3 mag for GRB150413A, as compared with respect to the nearby USNO-B1.0 stars, which lie within a radius of 3-4 arcminutes around the source. No absolute photometric calibration has been applied on these data. This message is quotable in publications. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17701 SUBJECT: GRB 150413A: Swift-BAT refined analysis DATE: 15/04/14 14:03:03 GMT FROM: Amy Lien at GSFC M. Stamatikos (OSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), 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 150413A (trigger #637899) (Markwardt, et al., GCN Circ. 17688). The BAT ground-calculated position is RA, Dec = 190.396, 71.839 deg which is RA(J2000) = 12h 41m 35.1s Dec(J2000) = +71d 50' 21.9" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 35%. The mask-weighted light curve shows a multi-peaked structure that starts at ~ T-100 s and ends at ~ T+200 s. The most prominent pulse starts at ~ T+90 s, peaks at ~ T+110 s, and ends at ~ T+120 s. T90 (15-350 keV) is 263.6 +- 36.7 sec (estimated error including systematics). The time-averaged spectrum from T-93.0 to T+209.8 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.75 +- 0.14. The fluence in the 15-150 keV band is 4.3 +- 0.4 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+110.78 sec in the 15-150 keV band is 1.6 +- 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/637899/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17702 SUBJECT: GRB 150413A: T7 and T18 optical observations DATE: 15/04/14 14:37:36 GMT FROM: Veli-Pekka Hentunen at Taurus Hill Obs,A95 Veli-Pekka Hentunen, Markku Nissinen and Tuomo Salmi (Taurus Hill Observatory, Varkaus, Finland) report: We have detected GRB 150413A optical afterglow at iTelescope observatory T7 and T18 (AstroCamp Observatory, Nerpio, Spain) using T7 0.43-m/6.8 and T18 0.32-m/8.0 astrographs. The observations were started at 2015-04-13 20:29:13 (UT) and stopped at 23:54:26 (UT). Fifteen unfiltered images and four photometric R filter images with 120 sec exposure time were made. The afterglow was detected at the following position RA 21:41:41.88 and DEC +71:50:27.9. The following magnitude were obtained from the observations using USNO-B1.0 1618-0098208 (R1=14.38) as a comparison star: Telescope Tmid(h)+T0 Filter Exp. time Mag T7 6.611 unfiltered 2x120s 17.2CR T7 6.728 unfiltered 3x120s 17.4CR T7 6.976 R 2x120s 17.7R T7 7.184 R 2x120s 17.9R T18 9.508 unfiltered 4x120s 18.0CR T18 9.685 unfiltered 4x120s 18.0CR T18 9.904 unfiltered 2x120s 18.0CR --- This email has been checked for viruses by Avast antivirus software. http://www.avast.com //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17704 SUBJECT: GRB 150413A: Bassano Bresciano Observatory optical observations DATE: 15/04/14 15:49:55 GMT FROM: Ulisse Quadri at Bassano Bresciano Obs U.Quadri, L.Strabla and R.Girelli report: We imaged the field of GRB 150413A detected by SWIFT(trigger 637899) with the robotic telescope of (IAU station 565) Bassano Bresciano Observatory, Italy (member of ISSP:Italian Supernovae Search Project) The observations started 5.44 hour after the GRB trigger, at the end of twilight, with our schmidt telescope D=320/400 mm F/D=3.1. Weather conditions were good. We co-added 13 series of 10 exposures of 120 sec each. Start T0+ End T0+ Vlim --------------------------------- 5.44 hour 10.26 hour 19.5 We clearly detect the optical counterpart at the following coordinates: 12h 41m 41.78s +71d 50m 27s +-2 arcsc. Magnitudes were estimated with the UCAC4 cat. and are not corrected for galactic dust extinction: ---------------------- JD CV mag ---------------------- 2457126.30650 17.92 2457126.32100 17.94 2457126.33532 18.10 2457126.34963 17.83 2457126.36395 17.99 2457126.37827 18.02 2457126.39258 18.21 2457126.40691 18.10 2457126.42122 18.21 2457126.43482 18.28 2457126.47849 18.54 2457126.49282 18.78 2457126.50714 19.20 The image, and magnitude plot are available at: http://www.osservatoriobassano.org/GRB.asp The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17705 SUBJECT: GRB 150413A DATE: 15/04/15 02:02:25 GMT FROM: Matteo M. M. Santangelo at OAC M.M.M. Santangelo and S. Gambogi report: We performed R and I bands CCD imagery of the field of GRB 150413A with the 0.60-meter f/9.83 Cassegrain reflector of Capannori Astronomical Observatory, Italy. Weather conditions were good, the seeing was fairly good, and the night-sky brightness at zenith was 20.15 mag/arcsec2 in V band. We clearly detected the optical counterpart of GRB 150413A. Magnitudes in Johnson/Cousins R and I bands derived by means of Mira professional 7 UE software are as follows: Date UT Exposure Band mag ± sigma 2015-04-13 20:56:22 300 s I 17.2 ± 0.2 2015-04-13 21:04:43 180 s R 17.6 ± 0.1 2015-04-13 21:11:02 360 s I 17.29 ± 0.04 Photometry is based on the nearby GSC 4397:1311 star, with magnitudes of comparison star from PPMXL. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17706 SUBJECT: GRB 150413A : Virtual Telescope optical observations DATE: 15/04/15 10:22:35 GMT FROM: Gianluca Masi at Bellatrix Astronomical Obs G. Masi and P. L. Catalano, the Virtual Telescope Project - Italy, report: We started time-series observations of GRB 150413A (C. B. Markwardt et al., GCN 17688) with the 17" robotic unit part of the Virtual Telescope (Ceccano, Italy) at 21:25:00 UT, that is 7.5 hours after the burst. An optical source is visible where described by K.Ivanov et al. (GCN 117689) on 60s and 120s exposures, unfiltered. The position of the source is RA: 12 41 41.97 Decl.: +71 50 27.7 (J2000.0, mean residuals of 0.2") and the magnitude was estimated to be 18.0, assuming R mags for the reference stars from UCAC-4. We covered the source for about one hour, detecting a fadind of about 0.4 mags from the start to the end of the series. Details are available on the page: http://goo.gl/8jCkhs This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17707 SUBJECT: GRB 150413A: additional P60 observations DATE: 15/04/15 11:29:50 GMT FROM: Daniel Perley at Caltech D. A. Perley (Caltech) and S. B. Cenko (GSFC) report: We have continued to follow the optical counterpart of GRB 150413A (Markwardt et al., GCN 17688; Ivanov et al., GCN 17689) with the Palomar 60-inch robotic telescope. A second griz epoch was acquired between 10:08:52 and 10:49:31 UT on the night of 2015-04-14, followed by two deeper epochs (one gri, one r only) on the night of UT 2015-04-15. Calibrating our r-band observations to a common set of USNO R-band reference stars, we derive the following photometry (statistical uncertainties only): dt_mid = 0.5602 day : R = 19.13 +/- 0.03 dt_mid = 0.8464 day : R = 20.23 +/- 0.06 dt_mid = 1.6034 day : R = 21.52 +/- 0.16 dt_mid = 1.8652 day : R = 21.74 +/- 0.18 This suggests steep decay over this period (decay index ~ 2.2). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17708 SUBJECT: GRB 150413A: AMI 15 GHz detection of possible radio counterpart DATE: 15/04/15 17:47:38 GMT FROM: Alexander van der Horst at George Washington U G.E. Anderson, R.P. Fender, T.D. Staley, K. Mooley (University of Oxford), A.J. van der Horst (George Washington University), A. Rowlinson (CASS) We observed the position of GRB 150413A (Markwardt et al., GCN 17688) at 15 GHz with the Arcminute Microkelvin Imager (AMI-LA) starting on 2015 April 14.745 to 14.973 UT, corresponding to 1.2 days post-burst. On this date we possibly detected a radio source coincident with the MASTER’s optical position (Ivanov et al., GCN 17689) with a preliminary flux of 0.19 +/- 0.04 mJy. There are no catalogued radio sources at this position. An earlier observation was conducted on 2015 April 13.747 to 13.914 UT, corresponding to 0.2 days post-burst, yielding a 3 sigma flux upper limit of 0.15 mJy. Further AMI monitoring is planned. We thank the AMI staff for scheduling these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17709 SUBJECT: GRB 150413A: GMG observation DATE: 15/04/16 04:29:34 GMT FROM: Jirong Mao at Yunnan Obs J. Mao, C. Wang and J.-M. Bai report: We observed the field of GRB 150413A (Markwardt et al., GCN 17688) with the 2.4-meter optical telescope at Gao-Mei-Gu (GMG) station of Yunnan Observatory. Observations began from 13:35:29 UT, April 14, 2015, about 23.7 hours after the trigger. We marginally detected the optical counterpart and estimated the magnitude as I~20.3. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17710 SUBJECT: GRB 150413A: Refined redshift DATE: 15/04/16 20:59:00 GMT FROM: Antonio de Ugarte Postigo at IAA-CSIC A. de Ugarte Postigo (IAA-CSIC, DARK/NBI) and L. Tomasella (INAF-OAPd) report: We have reanalysed the spectra of the afterglow of GRB 150413A (Markwardt et al. GCN 17688, Ivanov et al. GCN 17689) obtained by the Asiago Transient Classification Program (Tomasella et al. 2014, AN, 335, 841) with the Asiago 1.82 m Copernico Telescope +AFOSC (Tomasella et al. ATel 7391). In addition to the Ly-alpha feature already reported, we identify absorption features of SiII, SiII*, CII, SiIV, CIV, FeII and AlII at a common redshift of 3.139+/-0.003, slightly lower than previously reported by Sanchez-Ramírez (GCN 17697) and by Tomasella et al. (ATel 7391). In addition we report a tentative detection of a MgII intervening absorber at z=0.950+/-0.003. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17713 SUBJECT: LOAO B, R Observations of GRB150413A DATE: 15/04/17 06:54:10 GMT FROM: Changsu Choi at Seoul Nat U Changsu Choi, Myungshin Im (CEOU/SNU), Hyun-Il Sung (KASI), and Yuji Urata (NCU), on behalf of EAFON We observed the field of GRB 150413A, Swift GRB 150413A (Markwardt et al., GCN 17688) in B,R-band using the 1-m telescope at Mt. Lemmon Optical Observatory (LOAO) in Arizona, US We obtained B, R-band images on Apr. 14. We identified the optical afterglow in both band. The photometric calibraton is based on APASS catalog(AAVSO) in the observed field. Details of Photometry are below: UT Filter Mag Hour after detetion trigger(2015/04/13T 13:54:58) 2015/04/14T 04:54:07 B 20.95 +-0.25 15.13583 2015/04/14T 05:08:05 R 19.82 +-0.14 15.36861 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17714 SUBJECT: GRB 150413A: SAO RAS observations DATE: 15/04/17 11:23:58 GMT FROM: Moskvitin Alexander at SAO RAS A. S. Moskvitin (SAO RAS) report on behalf of larger GRB follow-up collaboration: The field of GRB 150413A (Markwardt et al., GCNC 17688) was observed with the Zeiss-1000, 1-m telescope of SAO RAS. The observations were carried out on the April, 16, 20:00:28--21:31:31 UT (T-T0 = 3.285 days). 16 x 300 sec. frames in Rc filter were obtained. The OT (Ivanov et al.,GCNC 17689) is absent in the stacked image, therefore R > 23.0. The limiting value is based on the R2 magnitudes of nearby USNO-B1 stars. We acknowledge A. S. Pozanenko, O. I. Spiridovova and V. S. Bychkova for the help in observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17715 SUBJECT: GRB 150413A: MITSuME Akeno Optical observation DATE: 15/04/17 13:17:03 GMT FROM: Taketoshi Yoshii at Tokyo Tech T.Fujiwara, Y. Saito, T. Yoshii, Y. Tachibana, H. Ohuchi, Y. Yano, S.Kurita, Y. Ono, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the field of GRB 150413A (C. B. Markwardt et al. GCN Circular #17688) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan. The observation started on 2015-04-13 15:58:02 UT (~2.1 h after the burst). We detected the previously reported optical afterglow (K.Ivanov et al. GCN Circular #17689) in the Ic band. The measured magnitudes are listed below. T0+ MID-UT T-EXP[sec] g' Rc Ic ---------------------------------------------------------------------- 263 min 4/13 18:17:28 240 > 17.3 > 17.2 16.09 +/- 0.30 2.04 days 4/15 14:52:50 15960 > 21.7 > 21.5 > 20.2 ---------------------------------------------------------------------- T0+ : Elapsed time after the burst T-EXP: Total Exposure time We used GSC2.3 catalog for flux calibration. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17718 SUBJECT: GRB 150413A: ISON-Ussuriysk optical observations DATE: 15/04/17 21:33:14 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), A. Stepura (UAFO, ISON), A. Matkin (UAFO, ISON), A. Volnova (IKI), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of the GRB 150413A (Markwardt et al., GCN 17688) with SANTEL-650 (0.65m) telescope of UAFO/ISON-Ussuriysk observatory sstarting on Apr., 14 (UT) 11:48:05. The afterglow (Ivanov et al., GCN 17689) is clearly detected in a combined image. Preliminary photometry the unfiltered combined image is following Date UT start t-T0 Filter Exp. OT OT_err (mid, days) (s) 2015-04-14 11:48:05 0.95859 none 117*60 20.35 0.15 The photometry is based on nearby USNO-B1.0 stars //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17721 SUBJECT: GRB 150413A: RTT150 optical observations DATE: 15/04/18 09:36:15 GMT FROM: Rodion Burenin at IKI, Moscow I. Bikmaev, E. Irtuganov, N. Sakhibullin (KFU/AST), R. Burenin, M. Pavlinsky, R. Sunyaev (IKI), I. Khamitov, H. Kirbiyik (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.) report: The field of the optical afterglow of GRB 150413A (Markwardt et al., GCN 17688, Ivanov et al., GCN 17689) was observed with Russian-Turkish 1.5-m telescope (RTT150, Bakirlitepe, TUBITAK National Observatory, Turkey) using the TFOSC instrument. We obtained series of Rc exposures in April 13/14 (50 frames x 300 sec, UT = 20:27 - 02:30 ) and in April 14/15 (4 frames x 600 sec, UT = 22:43 - 00:28, in partially cloudy conditions). The optical transient is clearly detected in each images. Using USNO-B1 1618-0098185 star at RA,DEC = 12:41:09.18 +71:50:32.4 (J2000) with R2 = 15.59 mag as a reference we estimated the R-magnitudes of the afterglow: T-T0, Mag. +/- Mag.err (days) 0.2932 17.39 +/- 0.03 0.5200 18.70 +/- 0.05 1.4318 21.4 +/- 0.2 RTT-150 light curve in April 13/14, 2015, can be found at: http://hea.iki.rssi.ru/grb/150413a/indexeng.html The break in the light curve at (T-T0) = 0.33 days is evident (break is seen also in V-band data of Bassano Bresciano Observatory, Quadri et al, GCN 17704). Before the break at (T-T0) = 0.33 days, the power law decay index is =~0.9, and it is close to 3.0 after that. Note, that decay index is close to 2.0 after (T-T0) = 0.7 days. Therefore, there are multiple breaks in the OT light curve. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17723 SUBJECT: GRB 150413A: Swift-XRT observations DATE: 15/04/20 09:26:50 GMT FROM: Claudio Pagani at U of Leicester J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester), V. D'Elia (ASDC), M. de Pasquale (INAF-IASFPA), A. Maselli (INAF-IASFPA), D.N. Burrows (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU) and C. B. Markwardt (NASA/GSFC) report on behalf of the Swift-XRT team: We have analysed 6.2 ks of XRT data for the Swift/BAT-detected burst GRB 150413A (Markwardt et al., GCN Circ. 17688). The data are entirely in Photon Counting (PC) mode, collected between T0+303.3 ks and T0+550.9 ks. No X-ray sources have been detected inside or close to the Swift/BAT error region. The 3-sigma upper limit at the position of the optical afterglow (Ivanov et al., GCN Circ. 17689) is 0.003 ct s^-1, corresponding to a 0.3-10 keV observed flux of 1.2e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum). The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at http://www.swift.ac.uk/ToO_GRBs/00637899. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17731 SUBJECT: GRB 150413A: Konus-Wind and Swift/BAT joint spectral analysis DATE: 15/04/23 10:46:32 GMT FROM: Anastasia Tsvetkova at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lysenko, and T. Cline on behalf of the Konus-Wind team, and T. Sakamoto (AGU), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC), D. Palmer (LANL), M. Stamatikos (OSU) and T. Ukwatta (GWU), report: We performed the Konus-Wind and the Swift/BAT joint spectral analysis of GRB 150413A (Swift/BAT trigger #637899: Markwardt et al., GCN Circ. 17688; Stamatikos et al., GCN Circ. 17701). Since the Konus-Wind observed this GRB in the waiting mode, we only have 3 channel spectral data for the Konus-Wind which cover the energy range from 20 keV to 1.2 MeV. The joint spectral analysis of the Konus-Wind and the Swift/BAT data allows us to derive the broad-band spectral parameters of this burst. The time intervals of the spectral data for each instrument are chosen from T0(BAT)-102.150 s to T0(BAT)+159.866 s (the time-integrated spectrum) and from T0(BAT)+95.098 s to T0(BAT)+118.650 s (the spectrum of the most prominent pulse) where T0(BAT) is the trigger time of BAT at 13:54:58 UTC. The energy ranges which we used in the joint spectral analysis are 20-1200 keV and 15-150 keV for the Konus-Wind and the Swift/BAT respectively. The spectral data of two instruments are fitted with the spectral model multiplied by the constant factor to take into account the systematic effective area uncertainties in the response matrices of each instrument. The spectrum of the most prominent pulse is well fitted with a power-law with exponential cutoff model: dN/dE ~ E^{alpha}*exp(-(2+alpha)*E/Epeak). No systematic residual from the best fit model is seen in the spectral data of each instrument. The BAT constant factor is 0.71(-0.12,+0.16) (the KW constant factor is fixed to 1). The best fit spectral parameters are: alpha = -1.01(-0.44,+0.65), and Epeak = 96(-22,+56) keV (chi2/dof = 60/57). The best fit spectral parameters for the GRB (Band) model fixing beta = -2.5 are: alpha = -1.00(-0.51,+0.84), and Epeak = 91(-26,+77) keV (chi2/dof = 63/57). The time-integrated spectrum is well fitted with a power-law model with the the photon index 1.77(-0.09,+0.09), chi2/dof = 68/58. The BAT constant factor is 0.70(-0.09,+0.11) (the KW constant factor is fixed to 1). The energy fluence in the 15-1200 keV band calculated by a power-law model for this 262.016 s interval is 1.42(-0.19,+0.20)x10^-5 erg/cm2. Assuming a redshift of 3.139 (de Ugarte Postigo and Tomasella, GCN Circ. 17710) and a standard cosmology model with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315, Omega_Lambda = 0.685, the isotropic energy release in the 1 keV - 10 MeV energy range is E_iso = 6.53(-1.29,+1.62)x10^53 erg. All the quoted errors are at the 90% confidence level. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB150413A/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17784 SUBJECT: GRB 150413A: CrAO optical observations DATE: 15/04/28 19:47:55 GMT FROM: Alexei Pozanenko at IKI, Moscow V. Rumyantsev (CrAO), K. Antoniuk (CrAO), E. Mazaeva (IKI), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of the GRB 150413A (Markwardt et al., GCN 17688) with AZT-11 telescope of CrAO observatory starting on Apr. 13 (UT) 17:39:02. Several images were take in R-filter. The afterglow (Ivanov et al., GCN 17689) is clearly detected in all single images of 180 s exposure. Preliminary photometry is following Date, UT start, OT, OT_err 2015-04-13 17 40 32.11 16.56 0.12 2015-04-13 17 43 36.17 16.97 0.30 2015-04-13 17 46 40.21 16.48 0.07 2015-04-13 17 49 44.26 16.73 0.11 2015-04-13 17 52 48.30 16.48 0.15 2015-04-13 17 55 52.37 16.62 0.13 2015-04-13 17 58 56.41 16.74 0.09 2015-04-13 18 02 00.58 16.63 0.13 2015-04-13 18 05 04.68 16.78 0.10 2015-04-13 18 08 08.76 16.77 0.09 2015-04-13 18 11 12.83 16.63 0.07 2015-04-13 18 14 16.87 16.74 0.06 2015-04-13 18 17 20.95 16.74 0.04 2015-04-13 18 20 25.30 16.76 0.06 2015-04-13 18 23 29.10 16.77 0.10 2015-04-13 18 26 33.15 16.90 0.08 2015-04-13 18 29 37.20 16.74 0.07 2015-04-13 18 32 41.25 16.71 0.05 2015-04-13 18 35 45.30 16.78 0.04 2015-04-13 18 38 49.36 16.77 0.03 2015-04-13 18 44 31.44 16.88 0.03 2015-04-13 18 47 35.48 16.81 0.03 2015-04-13 18 50 39.57 16.87 0.03 2015-04-13 18 53 43.66 16.92 0.03 2015-04-13 18 56 47.73 16.98 0.03 2015-04-13 18 59 51.90 17.02 0.03 2015-04-13 19 02 55.98 16.95 0.04 2015-04-13 19 06 00.64 16.94 0.04 2015-04-13 19 09 04.22 17.08 0.07 2015-04-13 19 12 08.35 17.05 0.06 The photometry is based on nearby USNO-B1.0 1618-0098185 (Xu et al., GCN 17693) assuming R=15.59. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17797 SUBJECT: GRB 150413A: AMI 15 GHz confirmation of radio counterpart DATE: 15/05/01 13:08:28 GMT FROM: Gemma Anderson at U of Oxford G. E. Anderson, R. P. Fender, T. D. Staley, K. Mooley (University of Oxford), A. J. van der Horst (George Washington University), A. Rowlinson (CASS) We re-observed the position of GRB 150413A (Markwardt et al., GCN 17688, Ivanov et al., GCN 17689) at 15 GHz with the Arcminute Microkelvin Imager (AMI-LA) following the possible detection of its radio counterpart reported in Anderson et al., GCN 17708. This observation took place on 2015 April 15.798 to 15.964 UT, corresponding to 2.2 days post-burst, resulting in a flux of 0.20 +/- 0.04 mJy. A follow-up AMI observation on 2015 April 23.947 to 24.114 UT, corresponding to 10.4 days post-burst, did not detection the radio counterpart with a 3 sigma upper limit of 0.1 mJy. We therefore confirm that the coincident radio source reported in Anderson et al., GCN 17708 is the radio counterpart to GRB 150413A. We thank the AMI staff for scheduling these observations.