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Sample records for burst grb 000301c

  1. The afterglow of the short/intermediate-duration gamma-ray burst GRB 000301C: A jet at z=2.04

    DEFF Research Database (Denmark)

    Jensen, B.L.; Fynbo, J.U.; Gorosabel, J.;

    2001-01-01

    We present Ulysses and NEAR data from the detection of the short or intermediate duration (2 s) gamma-ray burst GRB 000301C (2000 March 1.41 UT). The gamma-ray burst (GRB) was localised by the Inter Planetary Network (IPN) and RXTE to an area of similar to 50 arcmin(2). A fading optical counterpart...

  2. Hubble Space Telescope STIS Observations of GRB 000301C: CCD Imaging and Near-Ultraviolet MAMA Spectroscopy

    NARCIS (Netherlands)

    A. Smette; A.S. Fruchter; Th.R. Gull; K.C. Sahu; L. Petro; H. Ferguson; J. Rhoads; D.J. Lindler; R.A.M.J. Wijers

    2001-01-01

    We present Space Telescope Imaging Spectrograph observations of the optical transient (OT) counterpart of the gamma-ray burster GRB 000301C obtained 5 days after the burst, on 2000 March 6. CCD clear-aperture imaging reveals a R~=21.50+/-0.15 source with no apparent host galaxy. An 8000 s, 1150 Å

  3. Hubble Space Telescope STIS observations of GRB 000301C: CCD imaging and near-ultraviolet MAMA spectroscopy

    DEFF Research Database (Denmark)

    Smette, A.; Fruchter, A.S.; Gull, T.R.;

    2001-01-01

    We present Space Telescope Imaging Spectrograph observations of the optical transient (OT) counterpart of the c-ray burster GRB 000301C obtained 5 days after the burst, on 2000 March 6. CCD clear-aperture imaging reveals a R similar or equal to 21.50 +/- 0.15 source with no apparent host galaxy. ...

  4. HST\\/STIS observations of GRB000301C CCD imaging and NUV MAMA spectroscopy

    CERN Document Server

    Smette, A; Gull, T R; Sahu, K C; Petro, L; Ferguson, H; Rhoads, J E; Lindler, D; Gibbons, R A; Hogg, D W; Kouveliotou, C; Livio, M; Macchetto, D; Metzger, M R; Pedersen, H; Pian, E; Thorsett, S E; Wijers, R A M J; Fynbo, J P U; Gorosabel, J; Hjorth, J; Jensen, B L; Levine, A; Smith, D A; Cline, T; Hurley, K; Trombka, J I

    2000-01-01

    We present HST/STIS observations of the optical counterpart (OT) of the gamma-ray burster GRB 000301C obtained on 2000 March 6, five days after the burst. CCD clear aperture imaging reveals a R ~ 21.50+/-0.15 source with no apparent host galaxy. An 8000 s, 1150 18 on the line-of-sight to the OT. This value is conservatively a lower limit to the GRB redshift. However, the facts that large N(HI) system are usually considered as progenitors of present day galaxies and that other OTs are found associated with star forming galaxies strongly suggest that it is the GRB redshift. In any case, this represents the largest direct redshift determination of a gamma-ray burster to date. Our data are compatible with an OT spectrum represented by a power-law with an intrinsic index \\alpha = 1.2((f_nu \\propto nu^-alpha) and no extinction in the host galaxy or with alpha = 0.5 and extinction by a SMC-like dust in the OT rest-frame with A_V = 0.15. The large N(HI) and the lack of detected host is similar to the situation for d...

  5. The ``Christmas burst'' GRB 101225A revisited

    Science.gov (United States)

    Thöne, C. C.; de Ugarte Postigo, A.; Fryer, C. L.; Kann, D. A.

    2015-03-01

    Long GRBs are related to the death of massive stars and reveal themselves through synchrotron emission from highly relativistic jets. The `Christmas Burst' GRB 101225A was an exceptionally long GRB with a thermal afterglow, very different from the standard GRB. Initially, no spectroscopic redshift could be obtained and SED modeling yielded z=0.33. A plausible model was a He-NS star merger where the He-star had ejected part of its envelope in the common envelope phase during inspiral. The interaction between the jet and the previously ejected shell can explains the thermal emission. We obtained deep spectroscopy of the host galaxy which leads to a correction of the redshift to z=0.847. Despite the higher redshift, our model is still valid and theoretically better justified than the alternative suggestion of a blue supergiant progenitor proposed by Levan et al. (2014) for several ``ultra-long'' GRBs.

  6. The Unusually Long Duration Gamma-ray Burst GRB 000911

    CERN Document Server

    Price, P A; Kulkarni, S R; Djorgovski, S G; Fox, D W; Mahabal, A A; Hurley, K; Bloom, J S; Frail, D A; Galama, T J; Harrison, F A; Morrison, G; Reichart, D E; Yost, S A; Sari, R; Axelrod, T S; Cline, T; Golenetskii, S V; Mazets, E; Schmidt, B P; Trombka, J I

    2002-01-01

    Of all the well localized gamma-ray bursts, GRB 000911 has the longest duration (T_90 ~ 500 s), and ranks in the top 1% of BATSE bursts for fluence. Here, we report the discovery of the afterglow of this unique burst. In order to simultaneously fit our radio and optical observations, we are required to invoke a model involving an hard electron distribution, p ~ 1.5 and a jet-break time less than 1.5 day. A spectrum of the host galaxy taken 111 days after the burst reveals a single emission line, interpreted as [OII] at a redshift z = 1.0585, and a continuum break which we interpret as the Balmer limit at this redshift. Despite the long T_90, the afterglow of GRB 000911 is not unusual in any other way when compared to the set of afterglows studied to date. We conclude that the duration of the GRB plays little part in determining the physics of the afterglow.

  7. Gamma-Ray Burst Afterglows with Energy Injection: Homogeneous VersusWind External Media

    Institute of Scientific and Technical Information of China (English)

    王伟; 戴子高

    2001-01-01

    Assuming an adiabatic evolution of a gamma-ray burst (GRB) fireball interacting with an external medium,we calculate the hydrodynamics of the fireball with an energy injection from a strongly magnetic millisecond pulsar through magnetic dipole radiation, and obtain the light curve of the optical afterglow from the fireball by synchrotron radiation. The results are given both for an homogeneous external medium and for a wind ejected by GRB progenitor. Our calculations are also available in both ultra-relativistic and non-relativistic phases.Furthermore, the observed R-band light curve of GRB000301C can be well fitted in our model, which might provide a probe of the properties of GRB progenitors.

  8. The polarized gamma-ray burst GRB 061122

    Science.gov (United States)

    Götz, D.; Covino, S.; Fernández-Soto, A.; Laurent, P.; Bošnjak, Ž.

    2013-06-01

    We report on the polarization measure, obtained with IBIS on board INTEGRAL, of the prompt emission of GRB 061122. Over an 8 s interval containing the brightest part of the gamma-ray burst (GRB) we put a lower limit on its polarization fraction of 60 per cent at 68 per cent confidence level (c.l.) and of 33 per cent at 90 per cent c.l. on the 250-800 keV energy range. We performed late time optical and near-infrared imaging observations of the GRB field using the Telescopio Nazionale Galileo and the Canada-France-Hawaii Telescope. Our multiband (ugrizYJHK) photometry allowed us to identify the host galaxy of GRB 061122 and to build its spectral energy distribution. Using a photometric redshift code we fitted these data, and derived the basic properties of the galaxy, including its type and redshift, that we could constrain to the interval [0.57, 2.10] at a 90 per cent c.l., with a best-fitting value of z = 1.33. The polarization measurement in different energy bands, together with the distance determination, allowed us to put the most stringent limit (ξ ≲ 3.4 × 10-16) to date to a possible Lorentz invariance violation based on the vacuum birefringence effect, predicted by some quantum-gravity theories.

  9. Early polarization observations of the optical emission of gamma-ray bursts: GRB150301B and GRB150413A

    CERN Document Server

    Gorbovskoy, E S; Buckley, D; Kornilov, V G; Balanutsa, P V; Tyurina, N V; Kuznetsov, A S; Kuvshinov, D A; Gorbunov, I A; Vlasenko, D; Popova, E; Chazov, V V; Potter, S; Kotze, M; Kniazev, A; Gress, O A; Budnev, N M; Ivanov, K I; Yazev, S A; Tlatov, A G; Senik, V A; Dormidontov, D V; Parhomenko, A V; Krushinski, V V; Zalozhnich, I S; Castro-Tirado, R Alberto; Sanchez-Ramrez, R; Sergienko, Yu P; Gabovich, A; Yurkov, V V; Levato, H; Saffe, C; Mallamaci, C; Lopez, C; Podest, F

    2015-01-01

    We report early optical linear polarization observations of two gamma-ray bursts made with the MASTER robotic telescope network. We found the minimum polar- ization for GRB150301B to be 8% at the beginning of the initial stage, whereas we detected no polarization for GRB150413A either at the rising branch or after the burst reached the power-law afterglow stage. This is the earliest measurement of the polarization (in cosmological rest frame) of gamma-ray bursts. The primary intent of the paper is to discover optical emission and publish extremely rare (unique) high- quality light curves of the prompt optical emission of gamma-ray bursts during the non-monotonic stage of their evolution. We report that our team has discovered the optical counterpart of one of the bursts, GRB150413A.

  10. Light speed variation from gamma ray burst GRB 160509A

    CERN Document Server

    Xu, Haowei

    2016-01-01

    It is postulated in Einstein's relativity that the speed of light in vacuum is a constant for all observers. However, the effect of quantum gravity could bring an energy dependence of light speed. Even a tiny speed variation, when amplified by the cosmological distance, may be revealed by the observed time lags between photons with different energies from astrophysical sources. From the newly detected long gamma ray burst GRB~160509A, we find evidence to support the prediction for a linear form modification of light speed in cosmological space.

  11. Light speed variation from gamma ray burst GRB 160509A

    Science.gov (United States)

    Xu, Haowei; Ma, Bo-Qiang

    2016-09-01

    It is postulated in Einstein's relativity that the speed of light in vacuum is a constant for all observers. However, the effect of quantum gravity could bring an energy dependence of light speed. Even a tiny speed variation, when amplified by the cosmological distance, may be revealed by the observed time lags between photons with different energies from astrophysical sources. From the newly detected long gamma ray burst GRB 160509A, we find evidence to support the prediction for a linear form modification of light speed in cosmological space.

  12. The polarized Gamma-Ray Burst GRB 061122

    CERN Document Server

    Gotz, D; Fernandez-Soto, A; Laurent, P; Bosnjak, Z

    2013-01-01

    We report on the polarization measure, obtained with IBIS on board INTEGRAL, of the prompt emission of GRB 061122. Over an 8 s interval containing the brightest part of the Gamma-Ray Burst we put a lower limit on its polarization fraction of 60% at 68% c.l. and of 33% at 90% c.l. on the 250-800 keV energy range. We performed late time optical and near infra-red imaging observations of the GRB field using the Telescopio Nazionale Galileo (TNG), and the Canada-France-Hawaii Telescope (CFHT). Our multi-band (ugrizYJHK) photometry allowed us to identify the host galaxy of GRB 061122 and to build its SED. Using a photometric redshift code we fitted these data, and derived the basic properties of the galaxy, including its type and redshift, that we could constrain to the interval [0.57, 2.10] at a 90% c.l., with a best fit value of z=1.33. The polarization measurement in different energy bands, together with the distance determination, allowed us to put the most stringent limit (xi < 3.4x10-16) to date to a poss...

  13. Broadband Study of GRB 091127: A Sub-Energetic Burst at Higher Redshift?

    Science.gov (United States)

    Troja, E.; Sakamoto, T.; Guidorzi, C.; Norris, J. P.; Panaitescu, A.; Kobayashi, S.; Omodei, N.; Brown, J. C.; Burrows, D. N.; Evans, P. A.; Gehrels, N.; Marshall, F. E.; Mawson, N.; Melandri,; Mundell, C. G.; Oates, S. R.; Pal'shin, V.; Preece, R. D.; Racusin, J. L.; Steele, I. A.; Tanvir, N. R.; Vasileiou, V.; Wilson-Hodge, C.

    2012-01-01

    GRB 091127 is a bright gamma-ray burst (GRB) detected by Swift at a redshift z=0.49 and associated with SN 2009nz. We present the broadband analysis of the GRB prompt and afterglow emission and study its high-energy properties in the context of the GRB/SN association. While the high luminosity of the prompt emission and standard afterglow behavior are typical of cosmological long GRBs, its low energy release (E(sub gamma),bursts. We discuss the suppression of high-energy emission in this burst, and investigate whether this behavior could be connected with the sub-energetic nature of the explosion. Subject headings: gamma-ray bursts: individual (GRB 091127)

  14. GRB 060313: A New Paradigm for Short-Hard Bursts?

    CERN Document Server

    Roming, P W A; Palshin, V D; Pagani, C; Norris, J; Kumar, P; Krimm, H; Holland, S T; Gronwall, C; Blustin, A J; Zhang, B; Schady, P; Sakamoto, T; Osborne, J P; Nousek, J A; Marshall, F E; Mészáros, P; Golenetskii, S V; Gehrels, N; Frederiks, D D; Campana, S; Burrows, D N; Boyd, P T; Barthelmy, S; Aptekar, R L; Roming, Peter W. A.; Berk, Daniel Vanden; Palshin, Valentin; Pagani, Claudio; Norris, Jay; Kumar, Pawan; Krimm, Hans; Holland, Stephen T.; Gronwall, Caryl; Zhang, Bing; Schady, Patricia; Sakamoto, Takanori; Osborne, Julian P.; Nousek, John A.; Marshall, Frank E.; Meszaros, Peter; Golenetskii, Sergey V.; Gehrels, Neil; Frederiks, Dmitry D.; Campana, Sergio; Burrows, David N.; Boyd, Patricia T.; Barthelmy, Scott

    2006-01-01

    We report the simultaneous observations of the prompt emission in the gamma-ray and hard X-ray bands by the Swift-BAT and the KONUS-Wind instruments of the short-hard burst, GRB 060313. The observations reveal multiple peaks in both the gamma-ray and hard X-ray suggesting a highly variable outflow from the central explosion. We also describe the early-time observations of the X-ray and UV/Optical afterglows by the Swift XRT and UVOT instruments. The combination of the X-ray and UV/Optical observations provide the most comprehensive lightcurves to date of a short-hard burst at such an early epoch. The afterglows exhibit complex structure with different decay indices and flaring. This behavior can be explained by the combination of a structured jet, radiative loss of energy, and decreasing microphysics parameters occurring in a circum-burst medium with densities varying by a factor of approximately two on a length scale of 10^17 cm. These density variations are normally associated with the environment of a mass...

  15. VLT identification of the optical afterglow of the gamma-ray burst GRB 000131 at z=4.50

    DEFF Research Database (Denmark)

    Andersen, M. I.; Hjorth, J.; Pedersen, H.;

    2000-01-01

    We report the discovery of the gamma-ray burst GRB 000131 and its optical afterglow. The optical identification was made with the VLT 84 hours after the burst following a BATSE detection and an Inter Planetary Network localization. GRB 000131 was a bright, long-duration GRB, with an apparent prec...

  16. A serendipitous observation of the gamma-ray burst GRB 921013b field with EUVE

    DEFF Research Database (Denmark)

    Castro-Tirado, A.J.; Gorosabel, J.; Bowyer, S.;

    1999-01-01

    We report a serendipitous extreme ultraviolet observation by EUVE of the field containing GRB 921013b, similar to 11 hours after its occurrence. This burst was detected on 1992 October 13 by the WATCH and PHEBUS on Granat, and by the GRB experiment on Ulysses. The lack of any transient (or quiesc...

  17. Detectability of gravitational wave bursts from a class of neutron star starquake GRB models

    CERN Document Server

    Horváth, J E

    1995-01-01

    A large class of gamma-ray burst (GRB) models (overwhelming until recently) involve the release of energy in a neutron star quake. Even though the extreme isotropy of the GRB sky established by the BATSE experiment has now shifted the interest to cosmological models, the former starquake scenarios are still attractive and may naturally produce a gravitational wave burst that carries most of the released energy. We discuss the prospects for detection of these high-frequency bursts by the forthcoming interferometers and spheroidal antennas, emphasizing the most recent results on the distribution and nature of GRB sources. We find that, even if the overall picture is correct, the positive detection of GRB-associated gravitational wave bursts is unlikely and therefore these events will not be a prime target for the detectors.

  18. Fermi-LAT Observations of the Gamma-ray Burst GRB 130427A

    CERN Document Server

    Zhu, Sylvia; Dermer, Charles; Omodei, Nicola; Vianello, Giacomo; Xiong, Shaolin; Fermi-LAT, the

    2013-01-01

    The observations of the exceptionally bright gamma-ray burst (GRB) 130427A by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope provide constraints on the nature of such unique astrophysical sources. GRB 130427A had the largest fluence, highest-energy photon (95 GeV), longest $\\gamma$-ray duration (20 hours), and one of the largest isotropic energy releases ever observed from a GRB. Temporal and spectral analyses of GRB 130427A challenge the widely accepted model that the non-thermal high-energy emission in the afterglow phase of GRBs is synchrotron emission radiated by electrons accelerated at an external shock.

  19. Fermi-LAT Observations of the Gamma-Ray Burst GRB 130427A

    Science.gov (United States)

    Ackermann, M.; Ajello, M.; Asano, K.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; Gehrels, Cornelis

    2013-01-01

    The observations of the exceptionally bright gamma-ray burst (GRB) 130427A by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope provide constraints on the nature of these unique astrophysical sources. GRB 130427A had the largest fluence, highest-energy photon (95 GeV), longest gamma-ray duration (20 hours), and one of the largest isotropic energy releases ever observed from a GRB. Temporal and spectral analyses of GRB 130427A challenge the widely accepted model that the nonthermal high-energy emission in the afterglow phase of GRBs is synchrotron emission radiated by electrons accelerated at an external shock.

  20. Fermi-LAT Observations of the Gamma-Ray Burst GRB 130427A

    Science.gov (United States)

    Ackermann, M.; Ajello, M.; Asano, K.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Bissaldi, E.; Bonamente, E.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Burgess, J. Michael; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Cecchi, C.; Chaplin, V.; Charles, E.; Chekhtman, A.; Cheung, C. C.; Chiang, J.; Chiaro, G.; Ciprini, S.; Claus, R.; Cleveland, W.; Cohen-Tanugi, J.; Collazzi, A.; Cominsky, L. R.; Connaughton, V.; Conrad, J.; Cutini, S.; D'Ammando, F.; de Angelis, A.; DeKlotz, M.; de Palma, F.; Dermer, C. D.; Desiante, R.; Diekmann, A.; Di Venere, L.; Drell, P. S.; Drlica-Wagner, A.; Favuzzi, C.; Fegan, S. J.; Ferrara, E. C.; Finke, J.; Fitzpatrick, G.; Focke, W. B.; Franckowiak, A.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gehrels, N.; Germani, S.; Gibby, M.; Giglietto, N.; Giles, M.; Giordano, F.; Giroletti, M.; Godfrey, G.; Granot, J.; Grenier, I. A.; Grove, J. E.; Gruber, D.; Guiriec, S.; Hadasch, D.; Hanabata, Y.; Harding, A. K.; Hayashida, M.; Hays, E.; Horan, D.; Hughes, R. E.; Inoue, Y.; Jogler, T.; Jóhannesson, G.; Johnson, W. N.; Kawano, T.; Knödlseder, J.; Kocevski, D.; Kuss, M.; Lande, J.; Larsson, S.; Latronico, L.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Mayer, M.; Mazziotta, M. N.; McEnery, J. E.; Michelson, P. F.; Mizuno, T.; Moiseev, A. A.; Monzani, M. E.; Moretti, E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nemmen, R.; Nuss, E.; Ohno, M.; Ohsugi, T.; Okumura, A.; Omodei, N.; Orienti, M.; Paneque, D.; Pelassa, V.; Perkins, J. S.; Pesce-Rollins, M.; Petrosian, V.; Piron, F.; Pivato, G.; Porter, T. A.; Racusin, J. L.; Rainò, S.; Rando, R.; Razzano, M.; Razzaque, S.; Reimer, A.; Reimer, O.; Ritz, S.; Roth, M.; Ryde, F.; Sartori, A.; Parkinson, P. M. Saz; Scargle, J. D.; Schulz, A.; Sgrò, C.; Siskind, E. J.; Sonbas, E.; Spandre, G.; Spinelli, P.; Tajima, H.; Takahashi, H.; Thayer, J. G.; Thayer, J. B.; Thompson, D. J.; Tibaldo, L.; Tinivella, M.; Torres, D. F.; Tosti, G.; Troja, E.; Usher, T. L.; Vandenbroucke, J.; Vasileiou, V.; Vianello, G.; Vitale, V.; Winer, B. L.; Wood, K. S.; Yamazaki, R.; Younes, G.; Yu, H.-F.; Zhu, S. J.; Bhat, P. N.; Briggs, M. S.; Byrne, D.; Foley, S.; Goldstein, A.; Jenke, P.; Kippen, R. M.; Kouveliotou, C.; McBreen, S.; Meegan, C.; Paciesas, W. S.; Preece, R.; Rau, A.; Tierney, D.; van der Horst, A. J.; von Kienlin, A.; Wilson-Hodge, C.; Xiong, S.; Cusumano, G.; La Parola, V.; Cummings, J. R.

    2014-01-01

    The observations of the exceptionally bright gamma-ray burst (GRB) 130427A by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope provide constraints on the nature of these unique astrophysical sources. GRB 130427A had the largest fluence, highest-energy photon (95 GeV), longest γ-ray duration (20 hours), and one of the largest isotropic energy releases ever observed from a GRB. Temporal and spectral analyses of GRB 130427A challenge the widely accepted model that the nonthermal high-energy emission in the afterglow phase of GRBs is synchrotron emission radiated by electrons accelerated at an external shock.

  1. INTEGRAL and XMM-Newton observations of the weak gamma-ray burst GRB 030227

    DEFF Research Database (Denmark)

    Mereghetti, S.; Gotz, D.; Tiengo, A.; Beckmann, V.; Borkowski, J.; Courvoisier, T.J.L.; von Kienlin, A.; Schoenfelder, V.; Roques, J.P.; Bouchet, L.; Ubertini, P.; Castro-Tirado, A.; Lebrun, F.; Paul, Joachim; Lund, Niels; Mas-Hesse, J.M.; Hermsen, W.; den Hartog, P.R.; Winkler, C.

    2003-01-01

    We present International Gamma-Ray Astrophysical Laboratory ( INTEGRAL) and XMM-Newton observations of the prompt gamma-ray emission and the X-ray afterglow of GRB 030227, the first gamma-ray burst for which the quick localization obtained with the INTEGRAL Burst Alert System has led to the...

  2. Probing the Nature of Short Swift Bursts via Deep INTEGRAL Monitoring of GRB 050925

    Science.gov (United States)

    Sakamoto, T.; Barbier, L.; Barthelmy, S. D.; Cummings, J. R.; Fenimore, E. E.; Gehrels, N.; Krimm, H. A.; Markwardt, C. B.; Palmer, D. M.; Parsons, A. M.; Sato, G.; Stamatikos, M.; Tueller, J.

    2010-01-01

    We present results from Swift, XMM-Newton, and deep INTEGRAL monitoring in the region of GRB 050925. This short Swift burst is a candidate for a newly discovered soft gamma-ray repeater (SGR) with the following observational burst properties: 1) galactic plane (b=-0.1 deg) localization, 2) 150 msec duration, and 3) a blackbody rather than a simple power-law spectral shape (with a significance level of 97%). We found two possible X-ray counterparts of GRB 050925 by comparing the X-ray images from Swift XRT and XMM-Newton. Both X-ray sources show the transient behavior with a power-law decay index shallower than -1. We found no hard X-ray emission nor any additional burst from the location of GRB 050925 in approximately 5 Ms of INTEGRAL data. We discuss about the three BATSE short bursts which might be associated with GRB 050925, based on their location and the duration. Assuming GRB 050925 is associated with the H(sub II), regions (W 58) at the galactic longitude of 1=70 deg, we also discuss the source frame properties of GRB 050925.

  3. Unusual Central Engine Activity in the Double Burst GRB 110709B

    Science.gov (United States)

    Zhang, Bin-Bin; Burrows, David N.; Zhang, Bing; Meszaros, Peter; Stratta, Giulia; D'Elia, Valerio; Frederiks, Dmitry; Golenetskii, S.; Cummings, Jay R.; Wang, Xiang-Yu; Falcone, Abraham D.; Barthelmy, Scott D.; Gehrels, Neil

    2011-01-01

    The double burst, GRB 110709B, triggered Swift/BAT twice at 21:32:39 UT and 21:43:45 UT, respectively, on 9 July 2011. This is the first time we observed a GRB with two BAT triggers. In this paper, we present simultaneous Swift and Konus-WIND observations of this unusual GRB and its afterglow. If the two events are from the same physical origin, their different time-dependent spectral evolution suggest they must belong to different episodes of the central engine, which may be a magnetar-to-BH accretion system.

  4. GRB 080407: An Ultra-long Burst Discovered by the IPN

    Science.gov (United States)

    Cummings, J; Barthelmy, S.; Gehrels, N.; Krimm, H.; Palmer, D.; Palshin, V.; Hurley, K.; Goldsten, J.; Mitrofanov, I. G.; Boynton, W.; vonKienlln, A.; Feroci, M.; Aptekar, R.; Frederiks, D.; Golenetskli, S.; Mazets, E.; Svinkin, D.; Golovin, D.; Litvak, M. L.; Sanin, A. B.; Fellows, C.; Harshman, K.; Starr, R.; Rau, A.; Zhang, X.

    2012-01-01

    We present observations of the extremely long GRB 080704 obtained with the instruments of the Interplanetary Network (IPN). The observations reveal two distinct emission episodes, separated by a approx.1500 s long period of quiescence. The total burst duration is about 2100 s. We compare the temporal and spectral characteristics of this burst with those obtained for other ultra-long GRBs and discuss these characteristics in the context of different models.

  5. The afterglow and complex environment of the optically dim burst GRB 980613

    DEFF Research Database (Denmark)

    Hjorth, J.; Thomsen, Bente; Nielsen, S.R.;

    2002-01-01

    We report the identification of the optical afterglow of GRB 980613 in R- and I-band images obtained between 16 and 48 hr after the gamma-ray burst. Early near-infrared (NIR) H and K' observations are also reported. The afterglow was optically faint (R approximate to 23) at discovery but did not...

  6. The afterglow and complex environment of the optically dim burst GRB 980613

    DEFF Research Database (Denmark)

    Hjorth, J.; Thomsen, Bente; Nielsen, S.R.; Andersen, M.I.; Holland, S.T.; Fynbo, J.U.; Pedersen, H.; Jaunsen, A.O.; Halpern, J.P.; Fesen, R.; Gorosabel, J.; Castro-Tirado, A.; McMahon, R.G.; Hoenig, M.D.; Bjornsson, G.; Amati, L.; Tanvir, N.R.; Natarajan, P.

    2002-01-01

    of the optical afterglow was mainly due to the fairly at spectral shape rather than internal reddening in the host galaxy. We also present late-time Hubble Space Telescope/Space Telescope Imaging Spectrograph images of the field in which GRB 980613 occurred, obtained 799 days after the burst. These...

  7. GRB 070518: A Gamma-ray Burst with Optically Dim Luminosity

    CERN Document Server

    Xin, L P; Wang, J; Deng, J S; Urata, Y; Qiu, Y L; Huang, K Y; Hu, J Y; Wei, J Y

    2009-01-01

    We present our optical observations of {\\em Swift} GRB 070518 afterglow obtained at the 0.8-m Tsinghua University-National Astronomical Observatory of China telescope (TNT) at Xinglong Observatory. Our follow-up observations were performed from 512 sec after the burst trigger. With the upper limit of redshift $\\sim$0.7, GRB 070518 is found to be an optically dim burst. The spectra indices $\\beta_{ox}$ of optical to X-ray are slightly larger than 0.5, which implies the burst might be a dark burst. The extinction $A_{V}$ of the host galaxy is 3.2 mag inferred from the X-ray hydrogen column density with Galactic extinction law, and 0.3 mag with SMC extinction law. Also, it is similar to three other low-redshift optically dim bursts, which belong to XRR or XRF, and mid-term duration($T_{90}<10$, except for GRB 070419A, $T_{90}$=116s). Moreover, its $R$ band afterglow flux is well fitted by a single power-law with an index of 0.87. The optical afterglow and the X-ray afterglow in the normal segment might have t...

  8. The Burst Cluster: Dark Matter in a Cluster Merger Associated with the Short Gamma Ray Burst, GRB 050509B

    CERN Document Server

    Dahle, Hakon; Lopez, Laura A; Kouveliotou, Chryssa; Patel, Sandeep K; Rol, Evert; van der Horst, Alexander J; Fynbo, Johan P; Wijers, Ralph A M J; Burrows, David N; Gehrels, Neil; Grupe, Dirk; Ramirez-Ruiz, Enrico; Michalowski, Michal J

    2013-01-01

    We have identified a merging galaxy cluster with evidence of two distinct sub-clusters. The X-ray and optical data suggest that the subclusters are moving away from each other after closest approach. This cluster merger was discovered from observations of the well localized short-duration gamma-ray burst (GRB), GRB 050509B. The Swift/Burst Alert Telescope (BAT) source position is coincident with a cluster of galaxies ZwCl 1234.0+02916. The subsequent Swift/X-Ray Telescope (XRT) localization of the X-ray afterglow found the GRB coincident with 2MASX J12361286+2858580, a giant red elliptical galaxy in the cluster. Deep multi-epoch optical images were obtained to constrain the evolution of the GRB afterglow, including a 27480s exposure in the F814W band with Hubble Space Telescope Advanced Camera for Surveys (ACS), among the deepest imaging ever obtained towards a known galaxy cluster in a single passband. We perform a weak gravitational lensing analysis, including mapping the total mass distribution of the merg...

  9. The Afterglows of Swift-era Gamma-Ray Bursts. II. Type I GRB versus Type II GRB Optical Afterglows

    Science.gov (United States)

    Kann, D. A.; Klose, S.; Zhang, B.; Covino, S.; Butler, N. R.; Malesani, D.; Nakar, E.; Wilson, A. C.; Antonelli, L. A.; Chincarini, G.; Cobb, B. E.; D'Avanzo, P.; D'Elia, V.; Della Valle, M.; Ferrero, P.; Fugazza, D.; Gorosabel, J.; Israel, G. L.; Mannucci, F.; Piranomonte, S.; Schulze, S.; Stella, L.; Tagliaferri, G.; Wiersema, K.

    2011-06-01

    Gamma-ray bursts (GRBs) have been separated into two classes, originally along the lines of duration and spectral properties, called "short/hard" and "long/soft." The latter have been conclusively linked to the explosive deaths of massive stars, while the former are thought to result from the merger or collapse of compact objects. In recent years, indications have been accumulating that the short/hard versus long/soft division does not map directly onto what would be expected from the two classes of progenitors, leading to a new classification scheme called Type I and Type II which is based on multiple observational criteria. We use a large sample of GRB afterglow and prompt-emission data (adding further GRB afterglow observations in this work) to compare the optical afterglows (or the lack thereof) of Type I GRBs with those of Type II GRBs. In comparison to the afterglows of Type II GRBs, we find that those of Type I GRBs have a lower average luminosity and show an intrinsic spread of luminosities at least as wide. From late and deep upper limits on the optical transients, we establish limits on the maximum optical luminosity of any associated supernova (SN), confirming older works and adding new results. We use deep upper limits on Type I GRB optical afterglows to constrain the parameter space of possible mini-SN emission associated with a compact-object merger. Using the prompt-emission data, we search for correlations between the parameters of the prompt emission and the late optical afterglow luminosities. We find tentative correlations between the bolometric isotropic energy release and the optical afterglow luminosity at a fixed time after the trigger (positive), and between the host offset and the luminosity (negative), but no significant correlation between the isotropic energy release and the duration of the GRBs. We also discuss three anomalous GRBs, GRB 060505, GRB 060614, and GRB 060121, in light of their optical afterglow luminosities. Based in part

  10. INTEGRAL and XMM-Newton observations of the weak gamma-ray burst GRB 030227

    DEFF Research Database (Denmark)

    Mereghetti, S.; Gotz, D.; Tiengo, A.;

    2003-01-01

    We present International Gamma-Ray Astrophysical Laboratory ( INTEGRAL) and XMM-Newton observations of the prompt gamma-ray emission and the X-ray afterglow of GRB 030227, the first gamma-ray burst for which the quick localization obtained with the INTEGRAL Burst Alert System has led to the disco......We present International Gamma-Ray Astrophysical Laboratory ( INTEGRAL) and XMM-Newton observations of the prompt gamma-ray emission and the X-ray afterglow of GRB 030227, the first gamma-ray burst for which the quick localization obtained with the INTEGRAL Burst Alert System has led...... to the discovery of X-ray and optical afterglows. GRB 030227 had a duration of about 20 s and a peak flux of similar to1.1 photons cm(-2) s(-1) in the 20-200 keV energy range. The time-averaged spectrum can be fitted by a single power law with photon index similar to2, and we find some evidence for a hard......-to-soft spectral evolution. The X-ray afterglow has been detected starting only 8 hr after the prompt emission, with a 0.2-10 keV flux decreasing as t(-1) from 1.3 x 10(-12) to 5 x 10(-13) ergs cm(-2) s(-1). The afterglow spectrum is well described by a power law with photon index modified by a 1.94 +/- 0...

  11. Extreme Properties Of GRB061007: A Highly Energetic Or A Highly Collimated Burst?

    CERN Document Server

    Schady, P; Page, M J; Vetere, L; Pandey, S B; Wang, X Y; Cummings, J; Zhang, B; Zane, S; Breeveld, A; Burrows, D N; Gronwall, N G C; Hunsberger, S; Markwardt, C; Mason, K O; Mészáros, P; Oates, S R; Pagani, C; Poole, T S; Roming, P W A; Smith, P J; Vanden Berk, D E

    2006-01-01

    GRB061007 is the brightest gamma-ray burst (GRB) to be detected by Swift and is accompanied by an exceptionally luminous afterglow that had a V-band magnitude <11.1 at 80s after the prompt emission. From the start of the Swift observations the afterglow decayed as a power law with a slope of \\alpha_X=1.66+/-0.01 in the X-ray and \\alpha_{opt}=1.64+/-0.01 in the UV/optical, up to the point that it was no longer detected above background in the optical or X-ray bands. The brightness of this GRB and the similarity in the decay rate of the X-ray, optical and gamma-ray emission from 100s after the trigger distinguish this burst from others and present a challenge to the fireball model. The lack of a cooling or jet break in the afterglow up to \\~10^5s constrains any model that can produce the large luminosity observed in GRB061007, which we found to require either an excessively large kinetic energy or highly collimated outflow. Analysis of the multi-wavelength spectral and high-resolution temporal data taken wit...

  12. Extreme Properties Of GRB061007: A Highly Energetic OR Highly Collimated Burst?

    CERN Document Server

    Schady, P; Cummings, J; Page, M J; Pandey, S B; Wang, X Y; Vetere, L; Zhang, B; Zane, S; Breeveld, A; Burrows, D N; Gehrels, N; Gronwall, C; Ger, S H; Markwardt, C; Mason, K O; Mészáros, P; Oates, S R; Pagani, C; Poole, T S; Roming, P W A; Smith, P; Vanden Berk, D E

    2006-01-01

    GRB 061007 is the most energetic gamma-ray burst (GRB) to be detected by \\swift and is accompanied by an exceptionally luminous afterglow that had a $V$-band magnitude $< 11.1$ at 80 s after the prompt emission. From the start of the \\swift observations the afterglow decayed as a power law with a slope of $\\alpha_X=1.66\\pm 0.01$ in the X-ray and $\\alpha_{opt}=1.64\\pm 0.01$ in the UV/optical, up to the point that it was no longer detected above background in the optical or X-ray bands. The brightness of this GRB and the similarity in the decay rate of the X-ray, optical and $\\gamma$-ray emission from 100 s after the trigger, distinguish this burst from others and present a challenge to the fireball model. The lack of a cooling or jet break in the afterglow up to $\\sim 10^{5}$ s constrains any model that can produce the large luminosity observed in GRB 061007, which we found to require either an excessively large kinetic energy or highly collimated outflow. The multi-wavelength spectral and high-resolution t...

  13. GRB 140206A: the most distant polarized Gamma-Ray Burst

    CERN Document Server

    Gotz, D; Antier, S; Covino, S; D'Avanzo, P; D'Elia, V; Melandri, A

    2014-01-01

    The nature of the prompt gamma-ray emission of Gamma-Ray Bursts (GRBs) is still far from being completely elucidated. The measure of linear polarization is a powerful tool that can be used to put further constraints on the content and magnetization of the GRB relativistic outflows, as well as on the radiation processes at work. To date only a handful of polarization measurements are available for the prompt emission of GRBs. Here we present the analysis of the prompt emission of GRB 140206A, obtained with INTEGRAL/IBIS, Swift/BAT, and Fermi/GBM. Using INTEGRAL/IBIS as a Compton polarimeter we were able to constrain the linear polarization level of the second peak of this GRB as being larger than 28% at 90% c.l. We also present the GRB afterglow optical spectroscopy obtained at the Telescopio Nazionale Galileo (TNG), which allowed us the measure the distance of this GRB, z=2.739. This distance value together with the polarization measure obtained with IBIS, allowed us to derive the deepest and most reliable li...

  14. Two short bursts originating from different astrophysical systems: the genuine short GRB 090227B and the disguised short GRB 090510 by excess

    International Nuclear Information System (INIS)

    GRB 090227B and GRB 090510 are two gamma-ray bursts (GRBs) traditionally classified as short bursts. The major outcome of our analysis is that they indeed originate from different systems. In the case of GRB 090227B, from the inferred values of the total energy of the e+e- plasma, Etote+e- = (2.83 ± 0.15) x 1053 erg, the engulfed baryonic mass MB, expressed as B = MBc2 / Etote+e- = (4.1 ± 0.05) x 10-5, and the circumburst medium (CBM) average density, = (1.90 ± 0.20) x 10-5 cm-3, we have assumed the progenitor of this burst to be a symmetric neutron star (NS) merger with masses m = 1.34 M, radii R = 12.24 km, and crustal thicknesses of ∼ 0.47 km. In the case of GRB 090510, we have derived the total plasma energy, Etote+e- = (1.10 ± 0.06) x 1053 erg, the Baryon load, B = (1.45 ± 0.28) x 10-3, and the Lorentz factor at transparency, Γ = (6.7 ± 1.7) x 102, which are characteristic of the long GRB class, as well as a very high CBM density, (1.85 ± 0.14) x 103 cm-3. The joint effect of the high values of Γ and compresses in time and 'inflates' in intensity the extended afterglow, making GRB 090510 appear to be a short burst, which we here define as a 'disguised short GRB by excess', occurring in an overdense region with 103 cm-3.

  15. GRB 091024A and the nature of ultra-long gamma-ray bursts

    International Nuclear Information System (INIS)

    We present a broadband study of gamma-ray burst (GRB) 091024A within the context of other ultra-long-duration GRBs. An unusually long burst detected by Konus-Wind (KW), Swift, and Fermi, GRB 091024A has prompt emission episodes covering ∼1300 s, accompanied by bright and highly structured optical emission captured by various rapid-response facilities, including the 2 m autonomous robotic Faulkes North and Liverpool Telescopes, KAIT, S-LOTIS, and the Sonoita Research Observatory. We also observed the burst with 8 and 10 m class telescopes and determine the redshift to be z = 1.0924 ± 0.0004. We find no correlation between the optical and γ-ray peaks and interpret the optical light curve as being of external origin, caused by the reverse and forward shock of a highly magnetized jet (RB ≈ 100-200). Low-level emission is detected throughout the near-background quiescent period between the first two emission episodes of the KW data, suggesting continued central-engine activity; we discuss the implications of this ongoing emission and its impact on the afterglow evolution and predictions. We summarize the varied sample of historical GRBs with exceptionally long durations in gamma-rays (≳1000 s) and discuss the likelihood of these events being from a separate population; we suggest ultra-long GRBs represent the tail of the duration distribution of the long GRB population.

  16. GRB 091024A and the nature of ultra-long gamma-ray bursts

    Energy Technology Data Exchange (ETDEWEB)

    Virgili, F. J.; Mundell, C. G.; Harrison, R.; Kobayashi, S.; Steele, I. A.; Mottram, C. J.; Clay, N. R. [Astrophysics Research Institute, Liverpool John Moores University, Liverpool, L3 5RF (United Kingdom); Pal' shin, V. [Ioffe Physical Technical Institute, St. Petersburg 194021 (Russian Federation); Guidorzi, C. [Department of Physics and Earth Sciences, University of Ferrara, Via Saragat, 1, I-44122 Ferrara (Italy); Margutti, R.; Chornock, R. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Melandri, A. [INAF/Brera Astronomical Observatory, via Bianchi 46, I-23807 Merate (Italy); Henden, A. [AAVSO, 49 Bay State Road, Cambridge, MA 02138 (United States); Updike, A. C. [Department of Chemistry and Physics, Roger Williams University, Bristol, RI 02809 (United States); Cenko, S. B. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Tanvir, N. R. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Cucchiara, A. [Department of Astronomy and Astrophysics, UCO/Lick Observatory, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States); Gomboc, A. [Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana (Slovenia); Levan, A. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Cano, Z., E-mail: F.J.Virgili@ljmu.ac.uk [Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, 107 Reykjavik (Iceland); and others

    2013-11-20

    We present a broadband study of gamma-ray burst (GRB) 091024A within the context of other ultra-long-duration GRBs. An unusually long burst detected by Konus-Wind (KW), Swift, and Fermi, GRB 091024A has prompt emission episodes covering ∼1300 s, accompanied by bright and highly structured optical emission captured by various rapid-response facilities, including the 2 m autonomous robotic Faulkes North and Liverpool Telescopes, KAIT, S-LOTIS, and the Sonoita Research Observatory. We also observed the burst with 8 and 10 m class telescopes and determine the redshift to be z = 1.0924 ± 0.0004. We find no correlation between the optical and γ-ray peaks and interpret the optical light curve as being of external origin, caused by the reverse and forward shock of a highly magnetized jet (R{sub B} ≈ 100-200). Low-level emission is detected throughout the near-background quiescent period between the first two emission episodes of the KW data, suggesting continued central-engine activity; we discuss the implications of this ongoing emission and its impact on the afterglow evolution and predictions. We summarize the varied sample of historical GRBs with exceptionally long durations in gamma-rays (≳1000 s) and discuss the likelihood of these events being from a separate population; we suggest ultra-long GRBs represent the tail of the duration distribution of the long GRB population.

  17. A possible Macronova in the late afterglow of the `long-short' burst GRB 060614

    CERN Document Server

    Yang, Bin; Li, Xiang; Covino, Stefano; Zheng, Xian-Zhong; Hotokezaka, Kenta; Fan, Yi-Zhong; Piran, Tsvi; Wei, Da-Ming

    2015-01-01

    GRB 060614 was a unique burst straddling both long and short duration gamma-ray bursts and its physical origin is still debated. Here we re-examine the afterglow data of GRB 060614 and find a significant F814W-band excess at $t\\sim 13.6$ day after the burst observed by the {\\it Hubble Space Telescope (HST)}. This corresponds to an extremely-low luminosity $\\sim 3\\times 10^{40}~{\\rm erg~s^{-1}}$. The excess component has a very red spectrum and a rapid decline, both unexpected within the present theoretical framework of afterglow. We examine two possible sources of this signal$-$a very weak supernova and a Li-Paczynski Macronova/kilonova. We find that the observed signal is incompatible with a weak supernova. However, it is compatible with the ejection of $\\sim 0.03-0.1~M_\\odot$ of $r-$process material. If this interpretation is correct GRB 060614 arose from a compact binary (most likely a black hole$-$neutron star but also possibly a double neutron star) merger.

  18. The high-redshift gamma-ray burst GRB140515A

    CERN Document Server

    Melandri, A; D'Avanzo, P; Sanchez-Ramirez, R; Nappo, F; Nava, L; Japelj, J; Postigo, A de Ugarte; Oates, S; Campana, S; Covino, S; D'Elia, V; Ghirlanda, G; Gafton, E; Ghisellini, G; Gnedin, N; Goldoni, P; Gorosabel, J; Libbrecht, T; Malesani, D; Salvaterra, R; Thone, C C; Vergani, S D; Xu, D; Tagliaferri, G

    2015-01-01

    High-redshift gamma-ray bursts have several advantages for the study of the distant universe, providing unique information about the structure and properties of the galaxies in which they exploded. Spectroscopic identification with large ground-based telescopes has improved our knowledge of the class of such distant events. We present the multi-wavelength analysis of the high-$z$ Swift gamma-ray burst GRB140515A ($z = 6.327$). The best estimate of the neutral hydrogen fraction of the intergalactic medium (IGM) towards the burst is $x_{HI} \\leq 0.002$. The spectral absorption lines detected for this event are the weakest lines ever observed in gamma-ray burst afterglows, suggesting that GRB140515A exploded in a very low density environment. Its circum-burst medium is characterised by an average extinction (A$_{\\rm V} \\sim 0.1$) that seems to be typical of $z \\ge 6$ events. The observed multi-band light curves are explained either with a very flat injected spectrum ($p = 1.7$) or with a multi-component emission...

  19. BATSE burst location accuracy and constraints on the fraction of repeating GRB sources

    International Nuclear Information System (INIS)

    We use extensive simulations of GRB source repetition to investigate the ability of BATSE to detect source repetition and to place constraints on the fraction of repeating sources. From Monte Carlo simulations we find that the current uncertainty in BATSE burst locations severely limits our ability to confidently detect source repetition from distribution containing fewer than 10--15% repeaters. A fit of our repetition model to 260 BATSE catalog bursts yields a best-fit repeating fraction of fr=21% with a 90% confidence region ranging from 5.5 to 32.5%. By modifying the size of the measurement errors in our simulations we show that the location and width of the confidence region depends sensitively on the burst location errors. With BATSE's present location accuracy analysis of larger samples of bursts will not appreciably improve the constraint on the repeating fraction

  20. The Burst Cluster: Dark Matter in a Cluster Merger Associated with the Short Gamma-Ray Burst, GRB 050509B

    Science.gov (United States)

    Dahle, H.; Sarazin, C. L.; Lopez, L. A.; Kouveliotou, C.; Patel, S. K.; Rol, E.; van der Horst, A. J.; Fynbo, J.; Wijers, R. A. M. J.; Burrows, D. N.; Gehrels, N.; Grupe, D.; Ramirez-Ruiz, E.; Michałowski, M. J.

    2013-07-01

    We have identified a merging galaxy cluster with evidence of two distinct subclusters. The X-ray and optical data suggest that the subclusters are presently moving away from each other after closest approach. This cluster merger was discovered from observations of the first well-localized short-duration gamma-ray burst (GRB), GRB 050509B. The Swift/Burst Alert Telescope error position of the source is coincident with a cluster of galaxies ZwCl 1234.0+02916, while the subsequent Swift/X-Ray Telescope localization of the X-ray afterglow found the GRB coincident with 2MASX J12361286+2858580, a giant red elliptical galaxy in the cluster. Deep multi-epoch optical images were obtained in this field to constrain the evolution of the GRB afterglow, including a total of 27,480 s exposure in the F814W band with Hubble Space Telescope Advanced Camera for Surveys, among the deepest imaging ever obtained toward a known galaxy cluster in a single passband. We perform a weak gravitational lensing analysis based on these data, including mapping of the total mass distribution of the merger system with high spatial resolution. When combined with Chandra X-ray Observatory Advanced CCD Imaging Spectrometer and Swift/XRT observations, we are able to investigate the dynamical state of the merger to better understand the nature of the dark matter component. Our weak gravitational lensing measurements reveal a separation of the X-ray centroid of the western subcluster from the center of the mass and galaxy light distributions, which is somewhat similar to that of the famous "Bullet cluster," and we conclude that this "Burst cluster" adds another candidate to the previously known merger systems for determining the nature of dark matter, as well as for studying the environment of a short GRB. Finally, we discuss potential connections between the cluster dynamical state and/or matter composition, and compact object mergers, which is currently the leading model for the origin of short GRBs

  1. THE BURST CLUSTER: DARK MATTER IN A CLUSTER MERGER ASSOCIATED WITH THE SHORT GAMMA-RAY BURST, GRB 050509B

    Energy Technology Data Exchange (ETDEWEB)

    Dahle, H. [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, NO-0315 Oslo (Norway); Sarazin, C. L. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Lopez, L. A. [MIT-Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue, 37-664H, Cambridge, MA 02139 (United States); Kouveliotou, C. [Space Science Office, ZP12, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Patel, S. K. [Optical Sciences Corporation, 6767 Old Madison Pike, Suite 650, Huntsville, AL 35806 (United States); Rol, E.; Van der Horst, A. J.; Wijers, R. A. M. J. [Astronomical Institute ' Anton Pannekoek' , University of Amsterdam, Kruislaan 403, 1098 SJ Amsterdam (Netherlands); Fynbo, J.; Michalowski, M. J. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries vej 30, DK-2100 Copenhagen (Denmark); Burrows, D. N.; Grupe, D. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Gehrels, N. [NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Ramirez-Ruiz, E., E-mail: hdahle@astro.uio.no [Department of Astronomy and Astrophysics, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95060 (United States)

    2013-07-20

    We have identified a merging galaxy cluster with evidence of two distinct subclusters. The X-ray and optical data suggest that the subclusters are presently moving away from each other after closest approach. This cluster merger was discovered from observations of the first well-localized short-duration gamma-ray burst (GRB), GRB 050509B. The Swift/Burst Alert Telescope error position of the source is coincident with a cluster of galaxies ZwCl 1234.0+02916, while the subsequent Swift/X-Ray Telescope localization of the X-ray afterglow found the GRB coincident with 2MASX J12361286+2858580, a giant red elliptical galaxy in the cluster. Deep multi-epoch optical images were obtained in this field to constrain the evolution of the GRB afterglow, including a total of 27,480 s exposure in the F814W band with Hubble Space Telescope Advanced Camera for Surveys, among the deepest imaging ever obtained toward a known galaxy cluster in a single passband. We perform a weak gravitational lensing analysis based on these data, including mapping of the total mass distribution of the merger system with high spatial resolution. When combined with Chandra X-ray Observatory Advanced CCD Imaging Spectrometer and Swift/XRT observations, we are able to investigate the dynamical state of the merger to better understand the nature of the dark matter component. Our weak gravitational lensing measurements reveal a separation of the X-ray centroid of the western subcluster from the center of the mass and galaxy light distributions, which is somewhat similar to that of the famous 'Bullet cluster', and we conclude that this 'Burst cluster' adds another candidate to the previously known merger systems for determining the nature of dark matter, as well as for studying the environment of a short GRB. Finally, we discuss potential connections between the cluster dynamical state and/or matter composition, and compact object mergers, which is currently the leading model for the

  2. The supercritical pile gamma-ray burst model: The GRB afterglow steep decline and plateau phase

    Energy Technology Data Exchange (ETDEWEB)

    Sultana, J. [Mathematics Department, Faculty of Science, University of Malta, Msida MSD2080 (Malta); Kazanas, D. [Astrophysics Science Division, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Mastichiadis, A., E-mail: joseph.sultana@um.edu.mt [Department of Physics, University of Athens, Panepistimiopolis, GR 15783 Zografos (Greece)

    2013-12-10

    We present a process that accounts for the steep decline and plateau phase of the Swift X-Ray Telescope (XRT) light curves, vexing features of gamma-ray burst (GRB) phenomenology. This process is an integral part of the 'supercritical pile' GRB model, proposed a few years ago to account for the conversion of the GRB kinetic energy into radiation with a spectral peak at E {sub pk} ∼ m{sub e}c {sup 2}. We compute the evolution of the relativistic blast wave (RBW) Lorentz factor Γ to show that the radiation-reaction force due to the GRB emission can produce an abrupt, small (∼25%) decrease in Γ at a radius that is smaller (depending on conditions) than the deceleration radius R{sub D} . Because of this reduction, the kinematic criticality criterion of the 'supercritical pile' is no longer fulfilled. Transfer of the proton energy into electrons ceases and the GRB enters abruptly the afterglow phase at a luminosity smaller by ∼m{sub p} /m{sub e} than that of the prompt emission. If the radius at which this slow-down occurs is significantly smaller than R{sub D} , the RBW internal energy continues to drive the RBW expansion at a constant (new) Γ and its X-ray luminosity remains constant until R{sub D} is reached, at which point it resumes its more conventional decay, thereby completing the 'unexpected' XRT light curve phase. If this transition occurs at R ≅ R{sub D} , the steep decline is followed by a flux decrease instead of a 'plateau,' consistent with the conventional afterglow declines. Besides providing an account of these peculiarities, the model suggests that the afterglow phase may in fact begin before the RBW reaches R ≅ R{sub D} , thus providing novel insights into GRB phenomenology.

  3. The Supercritical Pile Gamma-Ray Burst Model: The GRB Afterglow Steep Decline and Plateau Phase

    Science.gov (United States)

    Sultana, Joseph; Kazanas, D.; Mastichiadis, A.

    2013-01-01

    We present a process that accounts for the steep decline and plateau phase of the Swift X-Ray Telescope (XRT) light curves, vexing features of gamma-ray burst (GRB) phenomenology. This process is an integral part of the "supercritical pile" GRB model, proposed a few years ago to account for the conversion of the GRB kinetic energy into radiation with a spectral peak at E(sub pk) is approx. m(sub e)C(exp 2). We compute the evolution of the relativistic blast wave (RBW) Lorentz factor Gamma to show that the radiation-reaction force due to the GRB emission can produce an abrupt, small (approx. 25%) decrease in Gamma at a radius that is smaller (depending on conditions) than the deceleration radius R(sub D). Because of this reduction, the kinematic criticality criterion of the "supercritical pile" is no longer fulfilled. Transfer of the proton energy into electrons ceases and the GRB enters abruptly the afterglow phase at a luminosity smaller by approx. m(sub p)/m(sub e) than that of the prompt emission. If the radius at which this slow-down occurs is significantly smaller than R(sub D), the RBW internal energy continues to drive the RBW expansion at a constant (new) Gamma and its X-ray luminosity remains constant until R(sub D) is reached, at which point it resumes its more conventional decay, thereby completing the "unexpected" XRT light curve phase. If this transition occurs at R is approx. equal to R(sub D), the steep decline is followed by a flux decrease instead of a "plateau," consistent with the conventional afterglow declines. Besides providing an account of these peculiarities, the model suggests that the afterglow phase may in fact begin before the RBW reaches R is approx. equal to R(sub D), thus providing novel insights into GRB phenomenology.

  4. Use of water-Cherenkov detectors to detect Gamma Ray Bursts at the Large Aperture GRB Observatory (LAGO)

    International Nuclear Information System (INIS)

    The Large Aperture GRB Observatory (LAGO) project aims at the detection of high energy photons from Gamma Ray Bursts (GRB) using the single particle technique in ground-based water-Cherenkov detectors (WCD). To reach a reasonable sensitivity, high altitude mountain sites have been selected in Mexico (Sierra Negra, 4550 m a.s.l.), Bolivia (Chacaltaya, 5300 m a.s.l.) and Venezuela (Merida, 4765 m a.s.l.). We report on detector calibration and operation at high altitude, search for bursts in 4 months of preliminary data, as well as search for signal at ground level when satellites report a burst

  5. Swift Observations of Gamma-Ray Burst Pulse Shapes: GRB Pulse Spectral Evolution Clarified

    CERN Document Server

    Hakkila, Jon; Sakamoto, Takanori; Morris, David; Neff, James E; Giblin, Timothy W

    2015-01-01

    Isolated Swift gamma-ray burst (GRB) pulses, like their higher-energy BATSE counterparts, emit the bulk of their pulsed emission as a hard-to-soft component that can be fitted by the Norris et al. (2005) empirical pulse model. This signal is overlaid by a fainter, three-peaked signal that can be modeled by an empirical wave-like function (Hakkila and Preece, 2014): the two fits combine to reproduce GRB pulses with distinctive three-peaked shapes. The precursor peak appears on or before the pulse rise and is often the hardest component, the central peak is the brightest, and the decay peak converts exponentially decaying emission into a long, soft, power-law tail. Accounting for systematic instrumental differences, the general characteristics of the fitted pulses are remarkably similar. Isolated GRB pulses are dominated by hard-to-soft evolution; this is more pronounced for asymmetric pulses than for symmetric ones. Isolated GRB pulses can also exhibit intensity tracking behaviors that, when observed, are tied...

  6. GRB 070714B-DISCOVERY OF THE HIGHEST SPECTROSCOPICALLY CONFIRMED SHORT BURST REDSHIFT

    International Nuclear Information System (INIS)

    We detect the optical afterglow and host galaxy of GRB 070714B. Our observations of the afterglow show an initial plateau in the light curve for approximately the first 5-25 minutes, and then steepening to a power-law decay with index α = 0.86 ± 0.10 for the period between 1 and 24 hr postburst. This is consistent with the X-ray light curve which shows an initial plateau followed by a similar subsequent decay. At late time, we detect a host galaxy at the location of the optical transient. Gemini Nod and Shuffle spectroscopic observations of the host show a single emission line at 7167 A which, based on a griz JHK photometric redshift, we conclude is the 3727 A [O II] line. We therefore find a redshift of z = 0.923. This redshift, as well as a subsequent probable spectroscopic redshift determination of GRB 070429B at z = 0.904 by two other groups significantly exceeds the previous highest spectroscopically confirmed short burst redshift of z = 0.546 for GRB 051221. This dramatically moves back the time at which we know short bursts were being formed and suggests that the present evidence for an old progenitor population may be observationally biased.

  7. GRB 090727 and gamma-ray bursts with early time optical emission

    CERN Document Server

    Kopac, D; Gomboc, A; Japelj, J; Mundell, C G; Guidorzi, C; Melandri, A; Bersier, D; Cano, Z; Smith, R J; Steele, I A; Virgili, F J

    2013-01-01

    We present a multi-wavelength analysis of gamma-ray burst GRB 090727, for which optical emission was detected during the prompt gamma-ray emission by the 2-m autonomous robotic Liverpool Telescope and subsequently monitored for a further two days with the Liverpool and Faulkes telescopes. Within the context of the standard fireball model, we rule out a reverse shock origin for the early time optical emission in GRB 090727 and instead conclude that the early time optical flash likely corresponds to emission from an internal dissipation processes. Putting GRB 090727 into a broader observational and theoretical context, we build a sample of 36 gamma-ray bursts (GRBs) with contemporaneous early time optical and gamma-ray detections. From these GRBs, we extract a sub-sample of 18 GRBs, which show optical peaks during prompt gamma-ray emission, and perform detailed temporal and spectral analysis in gamma-ray, X-ray, and optical bands. We find that in most cases early time optical emission shows sharp and steep beha...

  8. GRB 120422A: A LOW-LUMINOSITY GAMMA-RAY BURST DRIVEN BY A CENTRAL ENGINE

    International Nuclear Information System (INIS)

    GRB 120422A is a low-luminosity gamma-ray burst (GRB) associated with a bright supernova, which distinguishes itself by its relatively short T90 (∼5 s) and an energetic and steep-decaying X-ray tail. We analyze the Swift Burst Alert Telescope and X-ray Telescope data and discuss the physical implications. We show that the steep decline early in the X-ray light curve can be interpreted as the curvature tail of a late emission episode around 58-86 s, with a curved instantaneous spectrum at the end of the emission episode. Together with the main activity in the first ∼20 s and the weak emission from 40 s to 60 s, the prompt emission is variable, which points to a central engine origin in contrast to a shock-breakout origin, which is used to interpret some other nearby low-luminosity supernova GRBs. Both the curvature effect model and interpreting the early shallow decay as the coasting external forward shock emission in a wind medium provide a constraint on the bulk Lorentz factor Γ to be around several. Comparing the properties of GRB 120422A and other supernova GRBs, we find that the main criterion to distinguish engine-driven GRBs from shock-breakout GRBs is the time-averaged γ-ray luminosity. Engine-driven GRBs likely have a luminosity above ∼1048 erg s–1.

  9. GRB 120422A: a Low-Luminosity Gamma-Ray Burst Driven by a Central Engine

    Science.gov (United States)

    Zhang, Bin-Bin; Fan, Yi-Zhong; Shen, Rong-Feng; Xu, Dong; Zhang, Fu-Wen; Wei, Da-Ming; Burrows, David N.; Zhang, Bing; Gehrels, Neil

    2012-01-01

    GRB 120422A is a low-luminosity gamma-ray burst (GRB) associated with a bright supernova, which distinguishesitself by its relatively short T(sub 90) (approximately 5 s) and an energetic and steep-decaying X-ray tail. We analyze the Swift BurstAlert Telescope and X-ray Telescope data and discuss the physical implications. We show that the steep declineearly in the X-ray light curve can be interpreted as the curvature tail of a late emission episode around 58-86 s,with a curved instantaneous spectrum at the end of the emission episode. Together with the main activity in thefirst 20 s and the weak emission from 40 s to 60 s, the prompt emission is variable, which points to a centralengine origin in contrast to a shock-breakout origin, which is used to interpret some other nearby low-luminosity supernova GRBs. Both the curvature effect model and interpreting the early shallow decay as the coasting externalforward shock emission in a wind medium provide a constraint on the bulk Lorentz factor to be around several.Comparing the properties ofGRB 120422A and other supernova GRBs,we find that themain criterion to distinguish engine-driven GRBs from shock-breakout GRBs is the time-averaged -ray luminosity. Engine-driven GRBs likelyhave a luminosity above approximately 10(sup 48) erg s(sup -1).

  10. The Late-time Afterglow of the Extremely Energetic Short Burst GRB 090510 Revisited

    Science.gov (United States)

    Guelbenzu, A. Nicuesa; Klose, S.; Kruehler, T.; Greiner, J.; Rossi, A.; Kann, D. A.; Olivares, F.; Rau, A.; Afonso, P. M. J.; Elliott, J.; Filgas, R.; Yoldas, A. Kuepcue; McBreen, S.; Nardini, M.; Schady, P.; Schmidl, S.; Sudilovsky, V.; Updike, A. C.; Yoldas, A.

    2012-01-01

    Context. The Swift discovery of the short burst GRB 090510 has raised considerable attention mainly because of two reasons: first, it had a bright optical afterglow, and second it is among the most energetic events detected so far within the entire GRB population (long plus short). The afterglow of GRB 090510 was observed with Swift/UVOT and Swift/XRT and evidence of a jet break around 1.5 ks after the burst has been reported in the literature, implying that after this break the optical and X-ray light curve should fade with the same decay slope. Aims. As noted by several authors, the post-break decay slope seen in the UVOT data is much shallower than the steep decay in the X-ray band, pointing to a (theoretically hard to understand) excess of optical flux at late times. We assess here the validity of this peculiar behavior. Methods. We reduced and analyzed new afterglow light-curve data obtained with the multichannel imager GROND. These additional g'r'i'z' data were then combined with the UVOT and XRT data to study the behavior of the afterglow at late times more stringently. Results. Based on the densely sampled data set obtained with GROND, we find that the optical afterglow of GRB 090510 did indeed enter a steep decay phase starting around 22 ks after the burst. During this time the GROND optical light curve is achromatic, and its slope is identical to the slope of the X-ray data. In combination with the UVOT data this implies that a second break must have occurred in the optical light curve around 22 ks post burst, which, however, has no obvious counterpart in the X-ray band, contradicting the interpretation that this could be another jet break. Conclusions. The GROND data provide the missing piece of evidence that the optical afterglow of GRB 090510 did follow a post-jet break evolution at late times. The break seen in the optical light curve around 22 ks in combination with its missing counterpart in the X-ray band could be due to the passage of the

  11. GRB 080503: IMPLICATIONS OF A NAKED SHORT GAMMA-RAY BURST DOMINATED BY EXTENDED EMISSION

    International Nuclear Information System (INIS)

    We report on observations of GRB 080503, a short gamma-ray burst (GRB) with very bright extended emission (about 30 times the gamma-ray fluence of the initial spike) in conjunction with a thorough comparison to other short Swift events. In spite of the prompt-emission brightness, however, the optical counterpart is extraordinarily faint, never exceeding 25 mag in deep observations starting at ∼1 hr after the Burst Alert Telescope (BAT) trigger. The optical brightness peaks at ∼1 day and then falls sharply in a manner similar to the predictions of Li and Paczynski (1998) for supernova-like emission following compact binary mergers. However, a shallow spectral index and similar evolution in X-rays inferred from Chandra observations are more consistent with an afterglow interpretation. The extreme faintness of this probable afterglow relative to the bright gamma-ray emission argues for a very low density medium surrounding the burst (a 'naked' GRB), consistent with the lack of a coincident host galaxy down to 28.5 mag in deep Hubble Space Telescope imaging. The late optical and X-ray peak could be explained by a slightly off-axis jet or by a refreshed shock. Our observations reinforce the notion that short GRBs generally occur outside regions of active star formation, but demonstrate that in some cases the luminosity of the extended prompt emission can greatly exceed that of the short spike, which may constrain theoretical interpretation of this class of events. This extended emission is not the onset of an afterglow, and its relative brightness is probably either a viewing-angle effect or intrinsic to the central engine itself. Because most previous BAT short bursts without observed extended emission are too faint for this signature to have been detectable even if it were present at typical level, conclusions based solely on the observed presence or absence of extended emission in the existing Swift sample are premature.

  12. GRB 021219: the first Gamma-Ray Burst localized in real time with IBAS

    CERN Document Server

    Mereghetti, S; Beckmann, V; Von Kienlin, A; Ubertini, P; Bazzano, A; Foschini, L; Malaguti, G

    2003-01-01

    On December 19, 2002, during the Performance and Verification Phase of INTEGRAL, a Gamma-Ray Burst (GRB) has been detected and localized in real time with the INTEGRAL Burst Alert System (IBAS). Here we present the results obtained with the IBIS and SPI instruments. The burst had a time profile with a single peak lasting about 6 s. The peak spectrum can be described by a single power law with photon index $\\Gamma$=1.6$\\pm$0.1 and flux $\\sim$3.7 photons cm$^{-2}$ s$^{-1}$ (20 - 200 keV). The fluence in the same energy range is 9$\\times10^{-7}$ erg cm$^{-2}$. Time resolved spectroscopy performed with IBIS/ISGRI shows a clear hard to soft evolution of the spectrum.

  13. Swift Observations of Gamma-Ray Burst Pulse Shapes: GRB Pulse Spectral Evolution Clarified

    Science.gov (United States)

    Hakkila, Jon; Lien, Amy; Sakamoto, Takanori; Morris, David; Neff, James E.; Giblin, Timothy W.

    2015-12-01

    Isolated Swift gamma-ray burst (GRB) pulses, like their higher-energy BATSE counterparts, emit the bulk of their pulsed emission as a hard-to-soft component that can be fitted by the Norris et al. empirical pulse model. This signal is overlaid by a fainter, three-peaked signal that can be modeled by the residual fit of Hakkila & Preece: the two fits combine to reproduce GRB pulses with distinctive three-peaked shapes. The precursor peak appears on or before the pulse rise and is often the hardest component, the central peak is the brightest, and the decay peak converts exponentially decaying emission into a long, soft, power-law tail. Accounting for systematic instrumental differences, the general characteristics of the fitted pulses are remarkably similar. Isolated GRB pulses are dominated by hard-to-soft evolution; this is more pronounced for asymmetric pulses than for symmetric ones. Isolated GRB pulses can also exhibit intensity tracking behaviors that, when observed, are tied to the timing of the three peaks: pulses with the largest maximum hardnesses are hardest during the precursor, those with smaller maximum hardnesses are hardest during the central peak, and all pulses can re-harden during the central peak and/or during the decay peak. Since these behaviors are essentially seen in all isolated pulses, the distinction between “hard-to-soft and “intensity-tracking” pulses really no longer applies. Additionally, the triple-peaked nature of isolated GRB pulses seems to indicate that energy is injected on three separate occasions during the pulse duration: theoretical pulse models need to account for this.

  14. GRB 091024A and the nature of ultra-long gamma-ray bursts

    CERN Document Server

    Virgili, F J; Pal'shin, V; Guidorzi, C; Margutti, R; Melandri, A; Harrison, R; Kobayashi, S; Chornock, R; Henden, A; Updike, A C; Cenko, S B; Tanvir, N R; Steele, I A; Cucchiara, A; Gomboc, A; Levan, A; Cano, Z; Mottram, C J; Clay, N R; Bersier, D; Kopac, D; Japelj, J; Filippenko, A V; Li, W; Svinkin, D; Golenetskii, S; Hartmann, D H; Milne, P A; Williams, G; O'Brien, P T; Fox, D B; Berger, E

    2013-01-01

    We present a broadband study of gamma-ray burst (GRB) 091024A within the context of other ultra-long-duration GRBs. An unusually long burst detected by Konus-Wind, Swift, and Fermi, GRB 091024A has prompt emission episodes covering ~1300 s, accompanied by bright and highly structured optical emission captured by various rapid-response facilities, including the 2-m autonomous robotic Faulkes North and Liverpool Telescopes, KAIT, S-LOTIS, and SRO. We also observed the burst with 8- and 10-m class telescopes and determine the redshift to be z = 1.0924 \\pm 0.0004. We find no correlation between the optical and gamma-ray peaks and interpret the optical light curve as being of external origin, caused by the reverse and forward shock of a highly magnetized jet (R_B ~ 100-200). Low-level emission is detected throughout the near-background quiescent period between the first two emission episodes of the Konus-Wind data, suggesting continued central-engine activity; we discuss the implications of this ongoing emission a...

  15. Swift detects a remarkable gamma-ray burst, GRB 060614, that introduces a new classification scheme

    CERN Document Server

    Gehrels, N; Mangano, V; Barthelmy, S D; Burrows, D N; Granot, J; Kaneko, Y; Kouveliotou, C; Markwardt, C B; Mészáros, P; Nakar, E; Nousek, J A; O'Brien, P T; Page, M; Palmer, D M; Parsons, A M; Roming, P W A; Sakamoto, T; Sarazin, C L; Schady, P; Stamatikos, M; Woosley, S E

    2006-01-01

    Gamma ray bursts (GRBs) are known to come in two duration classes, separated at ~2 s. Long bursts originate from star forming regions in galaxies, have accompanying supernovae (SNe) when near enough to observe and are likely caused by massive-star collapsars. Recent observations show that short bursts originate in regions within their host galaxies with lower star formation rates consistent with binary neutron star (NS) or NS - black hole (BH) mergers. Moreover, although their hosts are predominantly nearby galaxies, no SNe have been so far associated with short GRBs. We report here on the bright, nearby GRB 060614 that does not fit in either class. Its ~102 s duration groups it with long GRBs, while its temporal lag and peak luminosity fall entirely within the short GRB subclass. Moreover, very deep optical observations exclude an accompanying supernova, similar to short GRBs. This combination of a long duration event without accompanying SN poses a challenge to both a collapsar and merging NS interpretation...

  16. The unusual radio afterglow of the ultra-long gamma-ray burst GRB 130925A

    CERN Document Server

    Horesh, Assaf; Perley, Daniel A; Kulkarni, S R; Hallinan, Gregg; Bellm, Eric

    2015-01-01

    GRB 130925A is one of the recent additions to the growing family of ultra-long GRBs (T90$ \\gtrsim 1000$ s). While the X-ray emission of ultra-long GRBs have been studied extensively in the past, no comprehensive radio dataset has been obtained so far. We report here the early discovery of an unusual radio afterglow associated with the ultra-long GRB 130925A. The radio emission peaks at low-frequencies ($\\sim 7$ GHz) at early times, only $2.2$ days after the burst occurred. More notably, the radio spectrum at frequencies above $10$ GHz exhibits a rather steep cut-off, compared to other long GRB radio afterglows. This cut-off can be explained if the emitting electrons are either mono-energetic or originate from a rather steep, $dN/dE \\propto E^{-4}$, power-law energy distribution. An alternative electron acceleration mechanism may be required to produce such an electron energy distribution. Furthermore, the radio spectrum exhibits a secondary underlying and slowly varying component. This may hint that the radio...

  17. Discerning the physical origins of cosmological Gamma-ray bursts based on multiple observational criteria: the cases of z=6.7 GRB 080913, z=8.3 GRB 090423, and some short/hard GRBs

    OpenAIRE

    Zhang, Bing; Zhang, Bin-Bin; Virgili, Francisco J.; Liang, En-Wei; Kann, D. Alexander; Wu, Xue-Feng; Proga, Daniel; LV, Hou-Jun; Toma, Kenji; Meszaros, Peter; Burrows, David N.; Roming, Peter W. A.; Gehrels, Neil

    2009-01-01

    (Abridged) The two high-redshift gamma-ray bursts, GRB 080913 at z=6.7 and GRB 090423 at z=8.3, recently detected by Swift appear as intrinsically short, hard GRBs. They could have been recognized by BATSE as short/hard GRBs should they have occurred at z

  18. Detection of the optical afterglow of GRB 000630: Implications for dark bursts

    DEFF Research Database (Denmark)

    Fynbo, J.U.; Jensen, B.L.; Gorosabel, J.;

    2001-01-01

    a power-law decline characterized by a decay slope of alpha = -1.035 +/- 0.097. A deep image obtained 25 days after the burst shows no indication of a contribution from a supernova or a host galaxy at the position of the transient. The closest detected galaxy is a R = 324.68 +/- 0.15 galaxy 2......We present the discovery of the optical transient of the long-duration gamma-ray burst GRB 000630. The optical transient was detected with the Nordic Optical Telescope 21.1 hours after the burst. At the time of discovery the magnitude of the transient was R = 23.04 +/- 0.08. The transient displayed...... conclude that i) based on the gamma-ray: properties of the current sample we cannot conclude that GRBs with no detected OTs belong to another class of GRBs than GRBs with detected OTs and ii) the majority (greater than or similar to 75%) of GRBs for which searches for optical afterglow have been...

  19. The Lag-Luminosity Relation in the GRB Source Frame: An Investigation with Swift BAT Bursts

    Science.gov (United States)

    Ukwatta, T. N.; Dhuga, K. S.; Stamatikos, M.; Dermer, C. D.; Sakamoto, T.; Sonbas, E.; Parke, W. C.; Maximon, L. C.; Linnemann, J. T.; Bhat, P. N.; Eskandarian, A.; Gehrels, N.; Abeysekara, A. U.; Tollefson, K.; Norris, J. P.

    2011-01-01

    Spectral lag. which is defined as the difference in time of arrival of high- and low-energy photons. is a common feature in gamma-ray bursts (GRBs). Previous investigations have shown a correlation between this lag and the isotropic peak luminosity for long duration bursts. However. most of the previous investigations used lags extracted in the observer frame only. In this work (based on a sample of 43 Swift long GRBs with known redshifts). we present an analysis of the lag-luminosity relation in the GRB source frame. Our analysis indicates a higher degree of correlation -0.82 +/- 0.05 (chance probability of approx. 5.5 x 10(exp -5) between the spectral lag and the isotropic peak luminosity, L(sub iso). with a best-fitting power-law index of -1.2 +/- 0.2. In addition, there is an anticorrelation between the source-frame spectral lag and the source-frame peak energy of the burst spectrum.

  20. A Search for Gravitational Waves Associated with the Gamma Ray Burst GRB030329 Using the LIGO Detectors

    CERN Document Server

    Abbott, R; Ageev, A; Allen, B; Amin, R; Anderson, S B; Anderson, W G; Araya, M; Armandula, H; Ashley, M; Asiri, F; Aufmuth, P; Aulbert, C; Babak, S; Balasubramanian, R; Ballmer, S; Barish, B C; Barker, C; Barker, D; Barnes, M; Barr, B; Barton, M A; Bayer, K; Beausoleil, R; Belczynski, K; Bennett, R; Berukoff, S J; Betzwieser, J; Bhawal, B; Bilenko, I A; Billingsley, G; Black, E; Blackburn, K; Blackburn, L; Bland, B; Bochner, B; Bogue, L; Bork, R; Bose, S; Brady, P R; Braginsky, V B; Brau, J E; Brown, D A; Bullington, A; Bunkowski, A; Buonanno, A; Burgess, R; Busby, D; Butler, W E; Byer, R L; Cadonati, L; Cagnoli, G; Camp, J B; Cantley, C A; Cardenas, L; Carter, K; Casey, M M; Castiglione, J; Chandler, A; Chapsky, J; Charlton, P; Chatterji, S; Chelkowski, S; Chen, Y; Chickarmane, V; Chin, D; Christensen, N; Churches, D; Cokelaer, T; Colacino, C; Coldwell, R; Coles, M; Cook, D; Corbitt, T; Coyne, D; Creighton, J D E; Creighton, T D; Crooks, D R M; Csatorday, P; Cusack, B J; Cutler, C; D'Ambrosio, E; Danzmann, K; Daw, E; De Bra, D; Delker, T; Dergachev, V; DeSalvo, R; Dhurandhar, S V; Di Credico, A; Díaz, M; Ding, H; Drever, R W P; Dupuis, R J; Edlund, J A; Ehrens, P; Elliffe, E J; Etzel, T; Evans, M; Evans, T; Fairhurst, S; Fallnich, C; Farnham, D; Fejer, M M; Findley, T; Fine, M; Finn, L S; Franzen, K Y; Freise, A; Frey, R; Fritschel, P; Frolov, V V; Fyffe, M; Ganezer, K S; Garofoli, J; Giaime, J A; Gillespie, A; Goda, K; González, G; Goler, S; Grandclément, P; Grant, A; Gray, C; Gretarsson, A M; Grimmett, D; Grote, H; Grünewald, S; Günther, M; Gustafson, E; Gustafson, R; Hamilton, W O; Hammond, M; Hanson, J; Hardham, C; Harms, J; Harry, G; Hartunian, A; Heefner, J; Hefetz, Y; Heinzel, G; Heng, I S; Hennessy, M; Hepler, N; Heptonstall, A; Heurs, M; Hewitson, M; Hild, S; Hindman, N; Hoang, P; Hough, J; Hrynevych, M; Hua, W; Ito, M; Itoh, Y; Ivanov, A; Jennrich, O; Johnson, B; Johnson, W W; Johnston, W R; Jones, D I; Jones, L; Jungwirth, D; Kalogera, V; Katsavounidis, E; Kawabe, K; Kawamura, S; Kells, W; Kern, J; Khan, A; Killbourn, S; Killow, C J; Kim, C; King, C; King, P; Klimenko, S; Koranda, S; Kotter, K; Kovalik, Yu; Kozak, D; Krishnan, B; Landry, M; Langdale, J; Lantz, B; Lawrence, R; Lazzarini, A; Lei, M; Leonor, I; Libbrecht, K; Libson, A; Lindquist, P; Liu, S; Logan, J; Lormand, M; Lubinski, M; Luck, H; Lyons, T T; Machenschalk, B; MacInnis, M; Mageswaran, M; Mailand, K; Majid, W; Malec, M; Mann, F; Marin, A; Marka, S; Maros, E; Mason, J; Mason, K; Matherny, O; Matone, L; Mavalvala, N; McCarthy, R; McClelland, D E; McHugh, M; McNabb, J W C; Mendell, G; Mercer, R A; Meshkov, S; Messaritaki, E; Messenger, C; Mitrofanov, V P; Mitselmakher, G; Mittleman, R; Miyakawa, O; Miyoki, S; Mohanty, S; Moreno, G; Mossavi, K; Müller, G; Mukherjee, S; Murray, P; Myers, J; Nagano, S; Nash, T; Nayak, R; Newton, G; Nocera, F; Noel, J S; Nutzman, P; Olson, T; O'Reilly, B; Ottaway, D J; Ottewill, A; Ouimette, D A; Overmier, H; Owen, B J; Pan, Y; Papa, M A; Parameshwaraiah, V; Parameswariah, C; Pedraza, M; Penn, S; Pitkin, M; Plissi, M; Prix, R; Quetschke, V; Raab, F; Radkins, H; Rahkola, R; Rakhmanov, M; Rao, S R; Rawlins, K; Ray-Majumder, S; Re, V; Redding, D; Regehr, M W; Regimbau, T; Reid, S; Reilly, K T; Reithmaier, K; Reitze, D H; Richman, S; Riesen, R; Riles, K; Rivera, B; Rizzi, A; Robertson, D I; Robertson, N A; Robison, L; Roddy, S; Rollins, J; Romano, J D; Romie, J; Rong, H; Rose, D; Rotthoff, E; Rowan, S; Rüdiger, A; Russell, P; Ryan, K; Salzman, I; Sandberg, V; Sanders, G H; Sannibale, V; Sathyaprakash, B; Saulson, P R; Savage, R; Sazonov, A; Schilling, R; Schlaufman, K; Schmidt, V; Schnabel, R; Schofield, R; Schutz, B F; Schwinberg, P; Scott, S M; Seader, S E; Searle, A C; Sears, B; Seel, S; Seifert, F; Sengupta, A S; Shapiro, C A; Shawhan, P; Shoemaker, D H; Shu, Q Z; Sibley, A; Siemens, X; Sievers, L; Sigg, D; Sintes, A M; Smith, J R; Smith, M; Smith, M R; Sneddon, P H; Spero, R; Stapfer, G; Steussy, D; Strain, K A; Strom, D; Stuver, A; Summerscales, T; Sumner, M C; Sutton, P J; Sylvestre, J; Takamori, A; Tanner, D B; Tariq, H; Taylor, I; Taylor, R; Thorne, K A; Thorne, K S; Tibbits, M; Tilav, S; Tinto, M; Tokmakov, K V; Torres, C; Torrie, C; Traylor, G; Tyler, W; Ugolini, D W; Ungarelli, C; Vallisneri, M; Van Putten, M H P M; Vass, S; Vecchio, A; Veitch, J; Vorvick, C; Vyachanin, S P; Wallace, L; Walther, H; Ward, H; Ware, B; Watts, K; Webber, D; Weidner, A; Weiland, U; Weinstein, A; Weiss, R; Welling, H; Wen, L; Wen, S; Whelan, J T; Whitcomb, S E; Whiting, B F; Wiley, S; Wilkinson, C; Willems, P A; Williams, P R; Williams, R; Willke, B; Wilson, A; Winjum, B J; Winkler, W; Wise, S; Wiseman, A G; Woan, G; Wooley, R; Worden, J; Wu, W; Yakushin, I; Yamamoto, H; Yoshida, S; Zaleski, K D; Zanolin, M; Zawischa, I; Zhang, L; Zhu, R; Zotov, N P; Zucker, M; Zweizig, J

    2005-01-01

    We have performed a search for bursts of gravitational waves associated with the very bright Gamma Ray Burst GRB030329, using the two detectors at the LIGO Hanford Observatory. Our search covered the most sensitive frequency range of the LIGO detectors (approximately 80-2048 Hz), and we specifically targeted signals shorter than 150 ms. Our search algorithm looks for excess correlated power between the two interferometers and thus makes minimal assumptions about the gravitational waveform. We observed no candidates with gravitational wave signal strength larger than a pre-determined threshold. We report frequency dependent upper limits on the strength of the gravitational waves associated with GRB030329. Near the most sensitive frequency region, around 250 Hz, our root-sum-square (RSS) gravitational wave strain sensitivity for optimally polarized bursts was better than h_RSS = 6E-21 Hz^{-1/2}. Our result is comparable to the best published results searching for association between gravitational waves and GRBs...

  1. GRB 081029: A Gamma-Ray Burst with a Multi-Component Afterglow

    Science.gov (United States)

    Holland, Stephen T.; De Pasquale, Massimiliano; Mao, Jirong; Sakamoto, Takanori; Schady, Patricia; Covino, Stefano; Fan, Yi-Zhong; Jin, Zhi-Ping; D'Avanzo, Paolo; Antonelli, Angelo; D'Elia, Valerio; Ohincarini, Guido; Fiore, Fabrizio; Pandey, Shashi Bhushan; Cobb, Bethany E.

    2012-01-01

    We present an analysis of the unusual optical light curve of the gamma-ray burst GRB 081029, a long-soft burst with a redshift of z = 3.8479. We combine X-ray and optical observations from the Swift X-Ray Telescope and the Swift Ultra Violet/Optical Telescope with ground-based optical and infrared data obtained using the REM, ROTSE, and CTIO 1.3-m telescopes to construct a detailed data set extending from 86 s to approx.100,000 s after the BAT trigger. Our data covers a wide energy range, from 10 keV to 0.77 eV (1.24 A to 16000 A). The X-ray afterglow shows a shallow initial decay followed by a rapid decay starting at about 18,000 s. The optical and infrared afterglow, however, shows an uncharacteristic rise at about 3000 s that does not correspond to any feature in the X-ray light curve. Our data are not consistent with synchrotron radiation from a jet interacting with an external medium, a two-component jet, or continuous energy injection from the central engine. We find that the optical light curves can be broadly explained by a collision between two ejecta shells within a two-component jet. A growing number of gamma-ray burst afterglows are consistent with complex jets, which suggests that some (or all) gamma-ray burst jets are complex and will require detailed modelling to fully understand them.injection

  2. GRB 060218/SN 2006aj: A Gamma-Ray Burst and Prompt Supernova at z=0.0335

    CERN Document Server

    Mirabal, N; An, D; Thorstensen, J R; Terndrup, D M

    2006-01-01

    We report the imaging and spectroscopic localization of GRB 060218 to a low-metallicity dwarf starburst galaxy at z = 0.03345 +/- 0.00006. In addition to making it the second nearest gamma-ray burst known, optical spectroscopy reveals the earliest detection of weak, supernova-like Si II near 5720 Angstroms, starting 1.95 days after the burst trigger. UBVRI photometry obtained between 1 and 26 days post-burst confirms the early rise of supernova light, and agrees with an upper limit Delta t < 159 s for the delay between the gamma-ray burst and the onset of the supernova explosion if the early appearance of a soft component in the X-ray spectrum is understood as a ``shock breakout''. Together, these results verify the long-hypothesized origin of soft gamma-ray bursts in the deaths of massive stars.

  3. Observations of the intense and ultra-long burst GRB 041219a with the Germanium spectrometer on INTEGRAL

    Science.gov (United States)

    McBreen, S.; Hanlon, L.; McGlynn, S.; McBreen, B.; Foley, S.; Preece, R.; von Kienlin, A.; Williams, O. R.

    2006-08-01

    Context.GRB 041219a is the brightest burst localised by INTEGRAL. The peak flux of 43 ph cm-2 s-1 (1.84 × 10-5 erg cm-2 s-1, 20 keV-8 MeV, 1 s integration) is greater than that for ~98% of all bursts and the T_90 duration of ~186 s (~20 keV-8 MeV) is longer than all but a small number of bursts. The intense burst occurred about ~250 s after the precursor and the long delay enabled optical and near infrared telescopes to observe the prompt emission.Aims.We present comprehensive results of the temporal and spectral analyses, including line and afterglow searches using the spectrometer, SPI, aboard INTEGRAL, BAT on Swift and ASM on Rossi X-ray Timing Explorer. We avail of multi-wavelength data to generate broadband spectra of GRB 041219a and afterglow. Methods.Spectra for the burst and sub-intervals were fit by the Band model and also by the quasithermal model. The high resolution Germanium spectrometer data were searched for emission and absorption features and for γ-ray afterglow. Results. The overall burst and sub-intervals are well fit by the Band model. The photon index below the break energy shows a marked change after the quiescent time interval. In addition the spectra are well described by a black body component with a power law. The burst was detected by BAT and ASM during the long quiescent interval in SPI indicating the central engine might not be dormant but that the emission occurs in different bands. No significant emission or absorption features were found and limits of 900 eV and 120 eV are set on the most significant features. No γ-ray afterglow was detected from the end of the prompt phase to ~12 h post-burst. Broadband spectra of the prompt emission were generated in 7 time intervals using γ-ray, X-ray, optical and near-infrared data and these were compared to the high-redshift burst GRB 050904. The optical and γ-ray emission are correlated in GRB 041219a. We estimate isotropic radiated energy (E_iso) to be ~5 × 1052 erg. The spectral lag was

  4. Diversity of GRB energetics vs. SN homogeneity: supernova 2013cq associated with the gamma-ray burst 130427A

    CERN Document Server

    Melandri, A; D'Elia, V; D'Avanzo, P; Della Valle, M; Mazzali, P A; Tagliaferri, G; Cano, Z; Levan, A J; Møller, P; Amati, L; Bernardini, M G; Bersier, D; Bufano, F; Campana, S; Castro-Tirado, A J; Covino, S; Ghirlanda, G; Hurley, K; Malesani, D; Masetti, N; Palazzi, E; Piranomonte, S; Rossi, A; Salvaterra, R; Starling, R L C; Tanaka, M; Tanvir, N R; Vergani, S D

    2014-01-01

    Long-duration gamma-ray bursts (GRBs) have been found to be associated with broad-lined type-Ic supernovae (SNe), but only a handful of cases have been studied in detail. Prompted by the discovery of the exceptionally bright, nearby GRB130427A (redshift z=0.3399), we aim at characterising the properties of its associated SN2013cq. This is the first opportunity to test directly the progenitors of high-luminosity GRBs. We monitored the field of the Swift long duration GRB130427A using the 3.6-m TNG and the 8.2-m VLT during the time interval between 3.6 and 51.6 days after the burst. Photometric and spectroscopic observations revealed the presence of the type Ic SN2013cq. Spectroscopic analysis suggests that SN2013cq resembles two previous GRB-SNe, SN1998bw and SN2010bh associated with GRB980425 and XRF100316D, respectively. The bolometric light curve of SN2013cq, which is significantly affected by the host galaxy contribution, is systematically more luminous than that of SN2010bh ($\\sim$ 2 mag at peak), but is ...

  5. Fermi/GBM observations of the ultra-long GRB 091024: A burst with an optical flash

    CERN Document Server

    Gruber, D; Foley, S; Nardini, M; Burlon, D; Rau, A; Bissaldi, E; von Kienlin, A; McBreen, S; Greiner, J; Bhat, P N; Briggs, M S; Burgess, J M; Chaplin, V L; Connaughton, V; Diehl, R; Fishman, G J; Gibby, M H; Giles, M M; Goldstein, A; Guiriec, S; van der Horst, A J; Kippen, R M; Kouveliotou, C; Lin, L; Meegan, C A; Paciesas, W S; Preece, R D; Tierney, D; Wilson-Hodge, C

    2011-01-01

    In this paper we examine gamma-ray and optical data of GRB 091024, a gamma-ray burst (GRB) with an extremely long duration of T90~1020 s, as observed with the Fermi Gamma-Ray Burst Monitor (GBM). We present spectral analysis of all three distinct emission episodes using data from Fermi/GBM. Because of the long nature of this event, many ground-based optical telescopes slewed to its location within a few minutes and thus were able to observe the GRB during its active period. We compare the optical and gamma-ray light curves. Furthermore, we estimate a lower limit on the bulk Lorentz factor from the variability and spectrum of the GBM light curve and compare it with that obtained from the peak time of the forward shock of the optical afterglow. From the spectral analysis we note that, despite its unusually long duration, this burst is similar to other long GRBs, i.e. there is spectral evolution (both the peak energy and the spectral index vary with time) and spectral lags are measured. We find that the optical ...

  6. GRB 120521C at z ∼ 6 and the properties of high-redshift γ-ray bursts

    Energy Technology Data Exchange (ETDEWEB)

    Laskar, Tanmoy; Berger, Edo; Zauderer, B. Ashley; Margutti, Raffaella; Fong, Wen-fai [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Tanvir, Nial; Wiersema, Klaas [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Levan, Andrew [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Perley, Daniel [Department of Astronomy, California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Menten, Karl [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Hrudkova, Marie [Isaac Newton Group of Telescopes, Apartado de Correos 321, E-387 00 Santa Cruz de la Palma, Canary Islands (Spain)

    2014-01-20

    We present optical, near-infrared, and radio observations of the afterglow of GRB 120521C. By modeling the multi-wavelength data set, we derive a photometric redshift of z ≈ 6.0, which we confirm with a low signal-to-noise ratio spectrum of the afterglow. We find that a model with a constant-density environment provides a good fit to the afterglow data, with an inferred density of n ≲ 0.05 cm{sup –3}. The radio observations reveal the presence of a jet break at t {sub jet} ≈ 7 d, corresponding to a jet opening angle of θ{sub jet} ≈ 3°. The beaming-corrected γ-ray and kinetic energies are E {sub γ} ≈ E{sub K} ≈ 3 × 10{sup 50} erg. We quantify the uncertainties in our results using a detailed Markov Chain Monte Carlo analysis, which allows us to uncover degeneracies between the physical parameters of the explosion. To compare GRB 120521C to other high-redshift bursts in a uniform manner we re-fit all available afterglow data for the two other bursts at z ≳ 6 with radio detections (GRBs 050904 and 090423). We find a jet break at t {sub jet} ≈ 15 d for GRB 090423, in contrast to previous work. Based on these three events, we find that γ-ray bursts (GRBs) at z ≳ 6 appear to explode in constant-density environments, and exhibit a wide range of energies and densities that span the range inferred for lower redshift bursts. On the other hand, we find a hint for narrower jets in the z ≳ 6 bursts, potentially indicating a larger true event rate at these redshifts. Overall, our results indicate that long GRBs share a common progenitor population at least to z ∼ 8.

  7. GRB 090417B and its Host Galaxy: A Step Towards an Understanding of Optically-Dark Gamma-Ray Bursts

    Science.gov (United States)

    Holland, Stephen T.; Sbarufatti, Boris; Shen, Rongfeng; Schady, Patricia; Cummings, Jay R.; Fonseca, Emmanuel; Fynbo, Johan P. U.; Jakobsson, Pall; Leitet, Elisabet; Linne, Staffan; Roming, Peter W.A.; Still, Martin; Zhang, Bing

    2009-01-01

    GRB 090417B was an unusually long burst with a T(sub 90) duration of at least 2130 s and a multi-peaked light curve at energies of 15-150 keV. It was optically dark and has been convincingly associated with a bright star-forming galaxy at a redshift of 0.345 that is broadly similar to the Milky Way. This is one of the few cases where a host galaxy has been clearly identified for a dark gamma-ray burst and thus an ideal candidate for studying the origin of dark bursts. We find that the dark nature of GRB 090417B can not be explained by high redshift, incomplete observations, or unusual physics in the production of the afterglow. The Swift/XRT X-ray data are consistent with the afterglow being obscured by a dense, localized sheet of dust approximately 30-80 pc from the burst along the line of sight. Assuming the standard relativistic fireball model for the afterglow we find that the optical flux is at least 2.5 mag fainter than predicted by the X -ray flux. We are able to explain the lack of an optical afterglow, and the evolution of the X -ray spectrum, by assuming that there is a sheet of dust along the line of sight approximately 30-80 pc from the progenitor. Our results suggest that this dust sheet imparts an extinction of A(sub v)> or = 12 mag, which is sufficient to explain the missing optical flux. GRB 090417B is an example of a gamma-ray burst that is dark due to the localized dust structure in its host galaxy.

  8. GRB 120521C at z ∼ 6 and the properties of high-redshift γ-ray bursts

    International Nuclear Information System (INIS)

    We present optical, near-infrared, and radio observations of the afterglow of GRB 120521C. By modeling the multi-wavelength data set, we derive a photometric redshift of z ≈ 6.0, which we confirm with a low signal-to-noise ratio spectrum of the afterglow. We find that a model with a constant-density environment provides a good fit to the afterglow data, with an inferred density of n ≲ 0.05 cm–3. The radio observations reveal the presence of a jet break at t jet ≈ 7 d, corresponding to a jet opening angle of θjet ≈ 3°. The beaming-corrected γ-ray and kinetic energies are E γ ≈ EK ≈ 3 × 1050 erg. We quantify the uncertainties in our results using a detailed Markov Chain Monte Carlo analysis, which allows us to uncover degeneracies between the physical parameters of the explosion. To compare GRB 120521C to other high-redshift bursts in a uniform manner we re-fit all available afterglow data for the two other bursts at z ≳ 6 with radio detections (GRBs 050904 and 090423). We find a jet break at t jet ≈ 15 d for GRB 090423, in contrast to previous work. Based on these three events, we find that γ-ray bursts (GRBs) at z ≳ 6 appear to explode in constant-density environments, and exhibit a wide range of energies and densities that span the range inferred for lower redshift bursts. On the other hand, we find a hint for narrower jets in the z ≳ 6 bursts, potentially indicating a larger true event rate at these redshifts. Overall, our results indicate that long GRBs share a common progenitor population at least to z ∼ 8.

  9. Photodisintegrated gamma rays and neutrinos from heavy nuclei in the gamma-ray burst jet of GRB 130427A

    Science.gov (United States)

    Joshi, Jagdish C.; Razzaque, Soebur; Moharana, Reetanjali

    2016-05-01

    Detection of ˜0.1-70 GeV prompt γ-ray emission from the exceptionally bright gamma-ray burst (GRB) 130427A by the Fermi-Large Area Telescope provides an opportunity to explore the physical processes of GeV γ-ray emission from the GRB jets. In this work, we discuss interactions of Iron and Oxygen nuclei with observed keV-MeV photons in the jet of GRB 130427A in order to explain an additional, hard spectral component observed during 11.5-33 s after trigger. The photodisintegration time-scale for Iron nuclei is comparable to or shorter than this duration. We find that γ rays resulting from the Iron nuclei disintegration can account for the hard power-law component of the spectra in the ˜1-70 GeV range, before the γγ → e± pair production with low-energy photons severely attenuates emission of higher energy photons. Electron antineutrinos from the secondary neutron decay, on the other hand, can be emitted with energies up to ˜2 TeV. The flux of these neutrinos is low and consistent with non-detection of GRB 130427A by the IceCube Neutrino Observatory. The required total energy in the Iron nuclei for this hadronic model for GeV emission is ≲10 times the observed total energy released in the prompt keV-MeV emission.

  10. A black hole preying on the star for a gamma-ray burst of GRB080503:Evidence for the second event in this new class

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this paper,we critically assess GRB080503,a short gamma-ray burst with very bright extended emission(about 30 times the gamma-ray fluence of the initial spike).The light curve of the prompt γ-ray emission of GRB080503 resembles that of GRB 060614 which has been suggested to be due to an event from an intermediate mass black hole(IMBH) preying on a star.We therefore propose that GRB080503 is also due to a similar event;the mass of the IMBH is estimated to be about 4.6×104 solar masses,and the engulfed star had about the same mass and size as the Sun.We also estimate that the total burst energy is about 7.67× 1050 ergs.

  11. GRB 051008

    DEFF Research Database (Denmark)

    Volnova, A. A.; Pozanenko, A. S.; Gorosabel, J.; Perley, D. A.; Frederiks, D. D.; Kann, D. A.; Rumyantsev, V. V.; Biryukov, V. V.; Castro-Tirado, A. J.; Ferrero, P.; Golenetskii, S. V.; Klose, S.; Loznikov, V. M.; Minaev, P. Yu.; Stecklum, B.; Svinkin, D. S.; Tsvetkova, A. E.; Ugarte Postigo, Antonio de; Ulanov, M. V.

    2014-01-01

    We present observations of the dark gamma-ray burst GRB 051008 provided by Swift/BAT, Swift/XRT, Konus-WIND, INTEGRAL/SPI-ACS in the high-energy domain and the Shajn, Swift/UVOT, Tautenburg, NOT, Gemini and Keck I telescopes in the optical and near-infrared bands. The burst was detected only in g...

  12. Deep Ly-alpha imaging of two z=2.04 GRB host galaxy fields

    CERN Document Server

    Fynbo, J P U; Thomsen, B; Hjorth, J; Gorosabel, J; Andersen, M I; Egholm, M P; Holland, S; Jensen, B L; Pedersen, H; Weidinger, M

    2002-01-01

    We report on the results of deep narrow-band Ly-alpha, U and I imaging of the fields of two GRBs at z=2.04 (GRB 000301C and GRB 000926). We find that the host galaxy of GRB 000926 is an extended, strong Ly-alpha emitter with a rest-frame equivalent width of 71+20-15 AA. The galaxy consists of two main components and several fainter knots. GRB 000926 occurred in the western component, whereas most of the Ly-alpha luminosity (about 65%) originates in the eastern component. Using archival HST images of the host galaxy we measure the spectral slopes (f_lambda prop. to lambda^beta) of the two components to beta = -2.4+-0.3 (east) and -1.4+-0.2 (west). This implies that both components contain at most small amounts of dust, consistent with the observed strong Ly-alpha emission. The western component has a slightly redder V-I colour than the eastern component, suggesting the presence of at least some dust. We do not detect the host galaxy of GRB 000301C in neither Ly-alpha emission nor in U and I-band images. We inf...

  13. GRB 080517: a local, low-luminosity gamma-ray burst in a dusty galaxy at z = 0.09

    Science.gov (United States)

    Stanway, Elizabeth R.; Levan, Andrew J.; Tanvir, Nial; Wiersema, Klaas; van der Horst, Alexander; Mundell, Carole G.; Guidorzi, Cristiano

    2015-02-01

    We present an analysis of the photometry and spectroscopy of the host galaxy of Swift-detected GRB 080517. From our optical spectroscopy, we identify a redshift of z = 0.089 ± 0.003, based on strong emission lines, making this a rare example of a very local, low-luminosity, long gamma-ray burst. The galaxy is detected in the radio with a flux density of S4.5 GHz = 0.22 ± 0.04 mJy - one of relatively few known gamma-ray bursts hosts with a securely measured radio flux. Both optical emission lines and a strong detection at 22 μm suggest that the host galaxy is forming stars rapidly, with an inferred star formation rate ˜16 M⊙ yr-1 and a high dust obscuration (E(B - V) > 1, based on sightlines to the nebular emission regions). The presence of a companion galaxy within a projected distance of 25 kpc, and almost identical in redshift, suggests that star formation may have been triggered by galaxy-galaxy interaction. However, fitting of the remarkably flat spectral energy distribution from the ultraviolet through to the infrared suggests that an older, 500 Myr post-starburst stellar population is present along with the ongoing star formation. We conclude that the host galaxy of GRB 080517 is a valuable addition to the still very small sample of well-studied local gamma-ray burst hosts.

  14. A Search for gravitational waves associated with the gamma ray burst GRB030329 using the LIGO detectors

    Energy Technology Data Exchange (ETDEWEB)

    Abbott, B.; Abbott, R.; Adhikari, R.; Ageev, A.; Allen, B.; Amin, R.; Anderson, S.B.; Anderson, W.G.; Araya, M.; Armandula, H.; Ashley, M.; Asiri, F.; Aufmuth, P.; Aulbert, C.; Babak, S.; Balasubramanian, R.; Ballmer, S.; Barish, B.C.; Barker, C.; Barker, D.; Barnes, M.; /Potsdam, Max Planck Inst. /Hannover, Max Planck Inst. Grav. /Australian

    2005-01-01

    We have performed a search for bursts of gravitational waves associated with the very bright Gamma Ray Burst GRB030329, using the two detectors at the LIGO Hanford Observatory. Our search covered the most sensitive frequency range of the LIGO detectors (approximately 80-2048 Hz), and we specifically targeted signals shorter than {approx_equal}150 ms. Our search algorithm looks for excess correlated power between the two interferometers and thus makes minimal assumptions about the gravitational waveform. We observed no candidates with gravitational wave signal strength larger than a pre-determined threshold. We report frequency dependent upper limits on the strength of the gravitational waves associated with GRB030329. Near the most sensitive frequency region, around {approx_equal}250 Hz, our root-sum-square (RSS) gravitational wave strain sensitivity for optimally polarized bursts was better than h{sub RSS} {approx_equal} 6 x 10{sup -21} Hz{sup -1/2}. Our result is comparable to the best published results searching for association between gravitational waves and GRBs.

  15. GRB060614 is at High Redshift, So No New Class of Gamma-Ray Bursts is Required

    OpenAIRE

    Schaefer, Bradley E.; Xiao, Limin

    2006-01-01

    Long duration Gamma-Ray Bursts (GRBs) have been strongly connected with core collapse supernovae, so it was surprising when the recent GRB060614 (with a reported redshift of 0.125) was found to have no visible supernova to deep limits. Three separate groups have reached the same conclusion that this event forces the existence of a new previously-unsuspected class of GRBs. The problem with this conclusion is that the redshift is not secure, as the measured galaxy emission lines simply give the...

  16. Photodisintegrated gamma rays and neutrinos from heavy nuclei in the gamma-ray burst jet of GRB 130427A

    CERN Document Server

    Joshi, Jagdish C; Moharana, Reetanjali

    2015-01-01

    Detection of $\\sim$ 0.1-70 GeV prompt $\\gamma$-ray emission from the exceptionally bright gamma-ray burst (GRB) 130427A by the ${\\it Fermi}$-Large Area Telescope provides an opportunity to explore the physical processes of GeV $\\gamma$-ray emission from the GRB jets. In this work we discuss interactions of Iron and Oxygen nuclei with observed keV-MeV photons in the jet of GRB 130427A in order to explain an additional, hard spectral component observed during 11.5-33 second after trigger. The photodisintegration time scale for Iron nuclei is comparable to or shorter than this duration. We find that $\\gamma$ rays resulting from the Iron nuclei disintegration can account for the hard power-law component of the spectra in the $\\sim$ 1-70 GeV range, before the $\\gamma\\gamma \\to e^\\pm$ pair production with low-energy photons severely attenuates emission of higher energy photons. Electron antineutrinos from the secondary neutron decay, on the other hand, can be emitted with energies up to $\\sim$ 2 TeV. The flux of th...

  17. Features of >130 Gamma-Ray Bursts at high energy: towards the 2nd Fermi LAT GRB catalog

    Science.gov (United States)

    Vianello, Giacomo; Omodei, Nicola; Fermi LAT Collaboration

    2016-01-01

    The high-energy emission from Gamma-Ray Bursts is a formidable probe for extreme physics, calling for highly relativistic sources with very large Lorentz factors. Despite the advancements prompted by observations from the Fermi Large Area Telescope and the Fermi Gamma-Ray Burst Monitor, as well as other observatories, many questions remain open, especially on radiative processes and mechanisms. We present here the most extensive search for GRBs at high energies performed so far, featuring a detection efficiency more than 50% better than previous works, and returning more than 130 detections. With this sample size, much larger than the 35 detections presented in the first Fermi/LAT GRB catalog, we are able to assess the characteristics of the population of GRBs at high energy with unprecedented sensitivity. We will review the preliminary results of this work, as well as their interpretation.

  18. The X-ray quiescence of Swift J195509.6+261406 (GRB 070610): an optical bursting X-ray binary?

    NARCIS (Netherlands)

    N. Rea; P.G. Jonker; G. Nelemans; J.A. Pons; M.M. Kasliwal; S.R. Kulkarni; R. Wijnands

    2011-01-01

    We report on an ~63 ks Chandra observation of the X-ray transient Swift J195509.6+261406 discovered as the afterglow of what was first believed to be a long-duration gamma-ray burst (GRB 070610). The outburst of this source was characterized by unique optical flares on timescales of second or less,

  19. The Lag-Luminosity Relation in the GRB Source-Frame: An Investigation with Swift BAT Bursts

    CERN Document Server

    Ukwatta, T N; Stamatikos, M; Dermer, C D; Sakamoto, T; Sonbas, E; Parke, W C; Maximon, L C; Linnemann, J T; Bhat, P N; Eskandarian, A; Gehrels, N; Abeysekara, U; Tollefson, K; Norris, J P

    2011-01-01

    Spectral lag, which is defined as the difference in time of arrival of high and low energy photons, is a common feature in Gamma-ray Bursts (GRBs). Previous investigations have shown a correlation between this lag and the isotropic peak luminosity for long duration bursts. However, most of the previous investigations used lags extracted in the observer-frame only. In this work (based on a sample of 43 Swift long GRBs with known redshifts), we present an analysis of the lag-luminosity relation in the GRB source-frame. Our analysis indicates a higher degree of correlation -0.82 +/- 0.05 (chance probability of ~ 5.5 x 10^-5) between the spectral lag and the isotropic peak luminosity, Liso, with a best-fit power-law index of -1.2 +/- 0.2, such that Liso proportional to lag^-1.2. In addition, there is an anti-correlation between the source-frame spectral lag and the source-frame peak energy of the burst spectrum, E_pk(1+z).

  20. A Merger Origin for Short Gamma-Ray Bursts Inferred from the Afterglow and Host Galaxy of GRB 050724

    CERN Document Server

    Berger, E; Cenko, S B; Gal-Yam, A; Soderberg, A M; Kasliwal, M; Leonard, D C; Cameron, P B; Frail, D A; Kulkarni, S R; Murphy, D C; Krzeminski, W; Piran, T; Lee, B L; Roth, K C; Moon, D S; Fox, D B; Harrison, F A; Persson, S E; Schmidt, B P; Penprase, B E; Rich, J; Peterson, B A; Cowie, L L

    2005-01-01

    Despite a rich phenomenology, gamma-ray bursts (GRBs) are divided into two classes based on their duration and spectral hardness -- the long-soft and the short-hard bursts. The discovery of afterglow emission from long GRBs was a watershed event, pinpointing their origin to star forming galaxies, and hence the death of massive stars, and indicating an energy release of about 10^51 erg. While theoretical arguments suggest that short GRBs are produced in the merger of compact object binaries (neutron stars or black holes), the progenitors, energetics, and environments of these events remain elusive despite recent localizations. Here we report the discovery of radio, optical, and infrared afterglow emission from the short-hard GRB 050724, which unambiguously associate it with an elliptical galaxy at a redshift, z=0.257. We show that the energy release is 1-3 orders of magnitude smaller than that of long GRBs, and that the burst ejecta may be collimated in jets. More importantly, the nature of the host galaxy for...

  1. The Lag-Luminosity Relation in the GRB Source-Frame: An Investigation with Swift BAT Bursts

    Science.gov (United States)

    Ukwatta, T. N.; Dhuga, K. S.; Stamatikos, M.; Dermer, C. D.; Sakamoto, T.; Sonbas, E.; Parke, W. C.; Maximon, L. C.; Linnemann, J. T.; Bhat, P. N.; Eskandarian, A.; Gehrels, N.; Abeysekara, U.; Tollefson, K.; Norris, J. P.

    2012-01-01

    Spectral lag, which is defined as the difference in time of arrival of high and low energy photons, is a common feature in Gamma-ray Bursts (GRBs). Previous investigations have shown a correlation between this lag and the isotropic peak luminosity for long duration bursts. However, most of the previous investigations used lags extracted in the observer-frame only. In this work (based on a sample of 43 Swift long GRBs with known redshifts), we present an analysis of the lag-luminosity relation in the GRB source-frame. Our analysis indicates a higher degree of correlation -0.82+/-0.05 (chance probability of approx 5.5 X 10(exp -5) between the spectral lag and the isotropic peak luminosity, L(sub iso), with a best-fit power-law index of -1.2 +/- 0.2, such that L(sub iso) varies as lag(exp -1.2). In addition, there is an anti-correlation between the source-frame spectral lag and the source-frame peak energy of the burst spectrum, E(sub pk)(1 + z).

  2. GRB 130925A: an ultra-long Gamma Ray Burst with a dust-echo afterglow, and implications for the origin of the ultra-long GRBs

    CERN Document Server

    Evans, P A; Osborne, J P; O'Brien, P T; Tanvir, N R; Frederiks, D D; Pal'shin, V D; Svinkin, D S; Lien, A; Cummings, J; Xiong, S; Zhang, B -B; Götz, D; Savchenko, V; Negoro, Hitoshi; Nakahira, Satoshi; Suzuki, Kazuhiko; Wiersema, K; Starling, R L C; Castro-Tirado, A J; Beardmore, A P; Sánchez-Ramírez, R; Gorosabel, J; Jeong, S; Kennea, J A; Burrows, D N; Gehrels, N

    2014-01-01

    GRB~130925A was an unusual GRB, consisting of 3 distinct episodes of high-energy emission spanning $\\sim$20 ks, making it a member of the proposed category of `ultra-long' bursts. It was also unusual in that its late-time X-ray emission observed by \\swift\\ was very soft, and showed a strong hard-to-soft spectral evolution with time. This evolution, rarely seen in GRB afterglows, can be well modelled as the dust-scattered echo of the prompt emission, with stringent limits on the contribution from the normal afterglow (i.e. external shock) emission. We consider and reject the possibility that GRB~130925A was some form of tidal disruption event, and instead show that if the circumburst density around GRB~130925A is low, the long duration of the burst and faint external shock emission are naturally explained. Indeed, we suggest that the ultra-long GRBs as a class can be explained as those with low circumburst densities, such that the deceleration time (at which point the material ejected from the nascent black ho...

  3. GRB 120422A/SN 2012bz: Bridging the gap between low- and high-luminosity gamma-ray bursts

    Science.gov (United States)

    Schulze, S.; Malesani, D.; Cucchiara, A.; Tanvir, N. R.; Krühler, T.; de Ugarte Postigo, A.; Leloudas, G.; Lyman, J.; Bersier, D.; Wiersema, K.; Perley, D. A.; Schady, P.; Gorosabel, J.; Anderson, J. P.; Castro-Tirado, A. J.; Cenko, S. B.; De Cia, A.; Ellerbroek, L. E.; Fynbo, J. P. U.; Greiner, J.; Hjorth, J.; Kann, D. A.; Kaper, L.; Klose, S.; Levan, A. J.; Martín, S.; O'Brien, P. T.; Page, K. L.; Pignata, G.; Rapaport, S.; Sánchez-Ramírez, R.; Sollerman, J.; Smith, I. A.; Sparre, M.; Thöne, C. C.; Watson, D. J.; Xu, D.; Bauer, F. E.; Bayliss, M.; Björnsson, G.; Bremer, M.; Cano, Z.; Covino, S.; D'Elia, V.; Frail, D. A.; Geier, S.; Goldoni, P.; Hartoog, O. E.; Jakobsson, P.; Korhonen, H.; Lee, K. Y.; Milvang-Jensen, B.; Nardini, M.; Nicuesa Guelbenzu, A.; Oguri, M.; Pandey, S. B.; Petitpas, G.; Rossi, A.; Sandberg, A.; Schmidl, S.; Tagliaferri, G.; Tilanus, R. P. J.; Winters, J. M.; Wright, D.; Wuyts, E.

    2014-06-01

    Context. At low redshift, a handful of gamma-ray bursts (GRBs) have been discovered with luminosities that are substantially lower (Liso ≲ 1048.5 erg s-1) than the average of more distant ones (Liso ≳ 1049.5 erg s-1). It has been suggested that the properties of several low-luminosity (low-L) GRBs are due to shock break-out, as opposed to the emission from ultrarelativistic jets. This has led to much debate about how the populations are connected. Aims: The burst at redshift z = 0.283 from 2012 April 22 is one of the very few examples of intermediate-L GRBs with a γ-ray luminosity of Liso ~ 1049.6-49.9 erg s-1 that have been detected up to now. With the robust detection of its accompanying supernova SN 2012bz, it has the potential to answer important questions on the origin of low- and high-L GRBs and the GRB-SN connection. Methods: We carried out a spectroscopy campaign using medium- and low-resolution spectrographs with 6-10-m class telescopes, which covered a time span of 37.3 days, and a multi-wavelength imaging campaign, which ranged from radio to X-ray energies over a duration of ~270 days. Furthermore, we used a tuneable filter that is centred at Hα to map star-formation in the host and the surrounding galaxies. We used these data to extract and model the properties of different radiation components and fitted the spectral energy distribution to extract the properties of the host galaxy. Results: Modelling the light curve and spectral energy distribution from the radio to the X-rays revealed that the blast wave expanded with an initial Lorentz factor of Γ0 ~ 50, which is a low value in comparison to high-L GRBs, and that the afterglow had an exceptionally low peak luminosity density of ≲2 × 1030 erg s-1 Hz-1 in the sub-mm. Because of the weak afterglow component, we were able to recover the signature of a shock break-out in an event that was not a genuine low-L GRB for the first time. At 1.4 hr after the burst, the stellar envelope had a blackbody

  4. Deep Ly alpha imaging of two z=2.04 GRB host galaxy fields

    DEFF Research Database (Denmark)

    Fynbo, J.P.U.; Møller, Per; Thomsen, Bente; Hjorth, J.; Gorosabel, J.; Andersen, M.I.; Egholm, M.P.; Jensen, B.L.; Pedersen, H.; Weidinger, M.

    2002-01-01

    spectral slopes (f(lambda) proportional to lambda(beta)) of the two components to beta = 2.4 +/- 0.3 (east)and -1.4 +/- 0.2 (west). This implies that both components contain at most small amounts of dust, consistent with the observed strong Lyalpha emission. The western component has a slightly redder V...... - I colour than the eastern component, suggesting the presence of at least some dust. We do not detect the host galaxy of GRB 000301C in neither Lyalpha emission nor in U and I broad-band images. The strongest limit comes from combining the narrow and U-band imaging where we infer a limit of U...... are candidate Lyalpha emitting galaxies in the environment of the host galaxies. Based on these detections we conclude that GRB 000926 occurred in one of the strongest centres of star formation within several Mpc, whereas GRB 000301C occurred in an intrinsically very faint galaxy far from being the...

  5. GRB 090618: different pulse temporal and spectral characteristics within a burst

    OpenAIRE

    Zhang, Fu-Wen

    2012-01-01

    GRB 090618 was simultaneously detected by Swift-BAT and Fermi-GBM. Its light curve shows two emission episodes consisting of four prominent pulses. The pulse in the first episode (episode A) has a smoother morphology than the three pulses in the second episode (episode B). Using the pulse peak-fit method, we have performed a detailed analysis of the temporal and spectral characteristics of these four pulses and found out that the first pulse (pulse A) exhibits distinctly different properties ...

  6. High energy emission of GRB 130821A: constraining the density profile of the circum-burst medium as well as the initial Lorentz factor of the outflow

    CERN Document Server

    Liang, Yun-Feng; He, Hao-Ning; Tam, Pak-Hin Thomas; Fan, Yi-Zhong; Wei, Da-Ming

    2013-01-01

    GRB 130821A was detected by Fermi-GBM/LAT, Konus-Wind, SPI-ACS/INTEGRAL, RHESSI and Mars Odyssey-HEND. Although the data of GRB 130821A are very limited, we show in this work that the high energy gamma-ray emission (i.e., above 100 MeV) alone imposes tight constraint on the density profile of the circum-burst medium as well as the initial Lorentz factor of the outflow. The temporal behavior of the high energy gamma-ray emission is consistent with the forward shock synchrotron radiation model and the circum-burst medium likely has a constant-density profile. The Lorentz factor is about a few hundred, similar to other bright GRBs.

  7. High energy emission of GRB 130821A: Constraining the density profile of the circum-burst medium as well as the initial Lorentz factor of the outflow

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Yun-Feng; Zhou, Bei; He, Hao-Ning; Fan, Yi-Zhong; Wei, Da-Ming [Key laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Tam, Pak-Hin Thomas, E-mail: phtam@phys.nthu.edu.tw [Institute of Astronomy and Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2014-02-01

    GRB 130821A was detected by Fermi-GBM/LAT, Konus-WIND, SPI-ACS/INTEGRAL, RHESSI and Mars Odyssey-HEND. Although the data of GRB 130821A are very limited, we show in this work that the high energy γ-ray emission (i.e., above 100 MeV) alone imposes tight constraint on the density profile of the circum-burst medium as well as the initial Lorentz factor of the outflow. The temporal behavior of the high energy γ-ray emission is consistent with the forward shock synchrotron radiation model, and the circum-burst medium likely has a constant-density profile. The Lorentz factor is about a few hundred, similar to other bright GRBs.

  8. Closing in on a Short-Hard Burst Progenitor: Constraints from Early-Time Optical Imaging and Spectroscopy of a Possible Host Galaxy of GRB 050509b

    CERN Document Server

    Bloom, J S; Pooley, D; Blake, C W; Foley, R J; Jha, S; Ramirez-Ruiz, E; Granot, J; Filippenko, A V; Sigurdsson, S; Barth, A J; Chen, H W; Cooper, M C; Falco, E E; Gal, R R; Gerke, B F; Gladders, M D; Greene, J E; Hennanwi, J; Ho, L C; Hurley, K; Koester, B P; Li, W; Lubin, L; Newman, J; Perley, D A; Squires, G K; Wood-Vasey, W M

    2006-01-01

    The localization of the short-duration, hard-spectrum gamma-ray burst GRB 050509b by the Swift satellite was a watershed event. Thanks to the nearly immediate relay of the GRB position, we began imaging the field ~8 minutes after the burst and have continued during the 8 days since. Though the X-ray Telescope (XRT) discovered an X-ray afterglow, the first ever of a short-hard burst, thus far no convincing optical/infrared candidate afterglow or supernova has been found for the object. We present a re-analysis of the XRT afterglow and find an absolute position that is ~4'' to the west of the XRT position reported previously. Near to this position is a bright elliptical galaxy with redshift z=0.2248 +- 0.0002, about 1' from the center of a rich cluster of galaxies. We find several fainter galaxies consistent with the XRT position from deep Keck imaging and have obtained Gemini spectra of two of these sources. Based on positional coincidences, we argue that the GRB and the bright elliptical are likely to be phys...

  9. A 'kilonova' associated with the short-duration γ-ray burst GRB 130603B

    DEFF Research Database (Denmark)

    Tanvir, N. R.; Levan, A. J.; Fruchter, A. S.;

    2013-01-01

    result in a faint transient, known as a 'kilonova', in the days following the burst. Indeed, it is speculated that this mechanism may be the predominant source of stable r-process elements in the Universe. Recent calculations suggest that much of the kilonova energy should appear in the near...... detection of gravitational waves. © 2013 Macmillan Publishers Limited. All rights reserved....

  10. The host galaxy and optical light curve of the gamma-ray burst GRB 980703

    DEFF Research Database (Denmark)

    Holland, S.; Fynbo, J.P.U.; Hjorth, J.; Gorosabel, J.; Pedersen, H.; Andersen, M.I.; Dar, A.; Thomsen, Bente; Møller, Per; Bjornsson, G.; Jaunsen, A.O.; Natarajan, P.; Tanvir, N.

    2001-01-01

    980703 with any special features in the host. The host galaxy appears to be a typical example of a compact star forming galaxy similar to those found in the Hubble Deep Field North. The R-band light curve of the optical afterglow associated with this gamma-ray burst is consistent with a single power...

  11. Closing in on a Short-Hard Burst Progenitor: Constraints From Early-Time Optical Imaging and Spectroscopy of a Possible Host Galaxy of GRB 050509b

    Energy Technology Data Exchange (ETDEWEB)

    Bloom, Joshua S.; Prochaska, J.X.; Pooley, D.; Blake, C.W.; Foley, R.J.; Jha, S.; Ramirez-Ruiz, E.; Granot, J.; Filippenko, A.V.; Sigurdsson, S.; Barth, A.J.; Chen,; Cooper, M.C.; Falco, E.E.; Gal, R.R.; Gerke, B.F.; Gladders, M.D.; Greene, J.E.; Hennanwi, J.; Ho, L.C.; Hurley, K.; /UC, Berkeley, Astron. Dept. /Lick Observ.

    2005-06-07

    The localization of the short-duration, hard-spectrum gamma-ray burst GRB050509b by the Swift satellite was a watershed event. Never before had a member of this mysterious subclass of classic GRBs been rapidly and precisely positioned in a sky accessible to the bevy of ground-based follow-up facilities. Thanks to the nearly immediate relay of the GRB position by Swift, we began imaging the GRB field 8 minutes after the burst and have continued during the 8 days since. Though the Swift X-ray Telescope (XRT) discovered an X-ray afterglow of GRB050509b, the first ever of a short-hard burst, thus far no convincing optical/infrared candidate afterglow or supernova has been found for the object. We present a re-analysis of the XRT afterglow and find an absolute position of R.A. = 12h36m13.59s, Decl. = +28{sup o}59'04.9'' (J2000), with a 1{sigma} uncertainty of 3.68'' in R.A., 3.52'' in Decl.; this is about 4'' to the west of the XRT position reported previously. Close to this position is a bright elliptical galaxy with redshift z = 0.2248 {+-} 0.0002, about 1' from the center of a rich cluster of galaxies. This cluster has detectable diffuse emission, with a temperature of kT = 5.25{sub -1.68}{sup +3.36} keV. We also find several ({approx}11) much fainter galaxies consistent with the XRT position from deep Keck imaging and have obtained Gemini spectra of several of these sources. Nevertheless we argue, based on positional coincidences, that the GRB and the bright elliptical are likely to be physically related. We thus have discovered reasonable evidence that at least some short-duration, hard-spectra GRBs are at cosmological distances. We also explore the connection of the properties of the burst and the afterglow, finding that GRB050509b was underluminous in both of these relative to long-duration GRBs. However, we also demonstrate that the ratio of the blast-wave energy to the {gamma}-ray energy is consistent with that

  12. GRB 090313

    DEFF Research Database (Denmark)

    de Ugarte Postigo...[}, A.; Goldoni, P.; Thöne, Christina; Malesani, Daniele; Fynbo, Johan Peter Uldall; Hjorth, Jens; Rasmussen, Per Kjærgaard; Andersen, Michael

    2010-01-01

    Context. X-shooter is the first second-generation instrument to become operative at the ESO Very Large Telescope (VLT). It is a broad-band medium-resolution spectrograph designed with gamma-ray burst (GRB) afterglow spectroscopy as one of its main science drivers. Aims. During the first commissio...... just a few minutes, X-shooter constitutes an significant leap forward on medium resolution spectroscopic studies of GRBs, their host galaxies and intervening systems, probing the early history of the Universe.......Context. X-shooter is the first second-generation instrument to become operative at the ESO Very Large Telescope (VLT). It is a broad-band medium-resolution spectrograph designed with gamma-ray burst (GRB) afterglow spectroscopy as one of its main science drivers. Aims. During the first...... identify as the redshift of the GRB. These features are composed of 3 components with different ionisation levels and velocities. Some of the features have never been observed before in a GRB at such a high redshift. Furthermore, we detect two intervening systems at redshifts of 1.8005 and 1...

  13. Prompt Ultraviolet-to-Soft X-Ray Emission of Gamma-Ray Bursts: Application to GRB 031203?

    CERN Document Server

    Li, Z; Li, Zhuo; Song, Li-Ming

    2004-01-01

    We discuss the prompt emission of GRBs, allowing for $\\gamma\\gamma$ pair production and synchrotron self-absorption. The observed hard spectra suggest heavy pair-loading in GRBs. The re-emission of the generated pairs results in the energy transmission from high-energy gamma-rays to long-wavelength radiation. Due to strong self-absorption, the synchrotron radiation by pairs is in optically thick regime. Thus, the re-emission would appear as a thermal-like spectral bump in the extreme-ultraviolet/soft X-ray band, other than the peak from the main burst. Recently, the prompt soft X-ray emission of GRB 031203 was detected thanks to the discovery of a delayed dust echo, and it seems to be consistent with the model prediction of a double-peak structure. The confirmation of the thermal-like feature and the double-peak structure by observation would indicate that the dominant radiation mechanism in GRBs is synchrotron rather than inverse-Compton radiation.

  14. DISCERNING THE PHYSICAL ORIGINS OF COSMOLOGICAL GAMMA-RAY BURSTS BASED ON MULTIPLE OBSERVATIONAL CRITERIA: THE CASES OF z = 6.7 GRB 080913, z = 8.2 GRB 090423, AND SOME SHORT/HARD GRBs

    International Nuclear Information System (INIS)

    The two high-redshift gamma-ray bursts, GRB 080913 at z = 6.7 and GRB 090423 at z = 8.2, recently detected by Swift appear as intrinsically short, hard GRBs. They could have been recognized by BATSE as short/hard GRBs should they have occurred at z ≤ 1. In order to address their physical origin, we perform a more thorough investigation on two physically distinct types (Type I/II) of cosmological GRBs and their observational characteristics. We reiterate the definitions of Type I/II GRBs and then review the following observational criteria and their physical motivations: supernova (SN) association, specific star-forming rate (SFR) of the host galaxy, location offset, duration, hardness, spectral lag, statistical correlations, energetics and collimation, afterglow properties, redshift distribution, luminosity function, and gravitational wave signature. Contrary to the traditional approach of assigning the physical category based on the gamma-ray properties (duration, hardness, and spectral lag), we take an alternative approach to define the Type I and Type II Gold Samples using several criteria that are more directly related to the GRB progenitors (SN association, host galaxy type, and specific SFR). We then study the properties of the two Gold Samples and compare them with the traditional long/soft and short/hard samples. We find that the Type II Gold Sample reasonably tracks the long/soft population, although it includes several intrinsically short (shorter than 1 s in the rest frame) GRBs. The Type I Gold Sample only has five GRBs, four of which are not strictly short but have extended emission. Other short/hard GRBs detected in the Swift era represent the BATSE short/hard sample well, but it is unclear whether all of them belong to Type I. We suggest that some (probably even most) high-luminosity short/hard GRBs instead belong to Type II. Based on multiple observational criteria, we suggest that GRB 080913 and GRB 090423 are more likely Type II events. In

  15. A double component in GRB 090618: a proto-black hole and a genuinely long gamma-ray burst

    Science.gov (United States)

    Izzo, L.; Ruffini, R.; Penacchioni, A. V.; Bianco, C. L.; Caito, L.; Chakrabarti, S. K.; Rueda, J. A.; Nandi, A.; Patricelli, B.

    2012-07-01

    Context. The joint X-ray and gamma-ray observations of GRB 090618 by very many satellites offer an unprecedented possibility of testing crucial aspects of theoretical models. In particular, they allow us to test (a) in the process of gravitational collapse, the formation of an optically thick e+e--baryon plasma self-accelerating to Lorentz factors in the range 200 AGILE, RT-2, and Suzaku, as well as from on-ground optical observatories. Methods: We analyzed the emission from GRB 090618 using several spectral models, with special attention to the thermal and power-law components. We determined the fundamental parameters of a canonical GRB within the context of the fireshell model, including the identification of the total energy of the e+e- plasma, Etote+e-, the proper GRB (P-GRB), the baryon load, the density and structure of the CBM. Results: We find evidence of the existence of two different episodes in GRB 090618. The first episode lasts 50 s and is characterized by a spectrum consisting of a thermal component, which evolves between kT = 54 keV and kT = 12 keV, and a power law with an average index γ = 1.75 ± 0.04. The second episode, which lasts for ~100 s, behaves as a canonical long GRB with a Lorentz gamma factor at transparency of Γ = 495, a temperature at transparency of 29.22 keV and with a characteristic size of the surrounding clouds of Rcl ~ 1015-16 cm and masses of ~1022-24 g. Conclusions: We support the recently proposed two-component nature of GRB 090618, namely, episode 1 and episode 2, with a specific theoretical analysis. We furthermore illustrate that episode 1 cannot be considered to be either a GRB or a part of a GRB event, but it appears to be related to the progenitor of the collapsing bare core, leading to the formation of the black hole, which we call a "proto-black hole". Thus, for the first time, we are witnessing the process of formation of a black hole from the phases just preceding the gravitational collapse all the way up to the

  16. Photometry and spectroscopy of GRB 060526: a detailed study of the afterglow and host galaxy of a z = 3.2 gamma-ray burst

    Science.gov (United States)

    Thöne, C. C.; Kann, D. A.; Jóhannesson, G.; Selj, J. H.; Jaunsen, A. O.; Fynbo, J. P. U.; Akerlof, C. W.; Baliyan, K. S.; Bartolini, C.; Bikmaev, I. F.; Bloom, J. S.; Burenin, R. A.; Cobb, B. E.; Covino, S.; Curran, P. A.; Dahle, H.; Ferrero, A.; Foley, S.; French, J.; Fruchter, A. S.; Ganesh, S.; Graham, J. F.; Greco, G.; Guarnieri, A.; Hanlon, L.; Hjorth, J.; Ibrahimov, M.; Israel, G. L.; Jakobsson, P.; Jelínek, M.; Jensen, B. L.; Jørgensen, U. G.; Khamitov, I. M.; Koch, T. S.; Levan, A. J.; Malesani, D.; Masetti, N.; Meehan, S.; Melady, G.; Nanni, D.; Näränen, J.; Pakstiene, E.; Pavlinsky, M. N.; Perley, D. A.; Piccioni, A.; Pizzichini, G.; Pozanenko, A.; Roming, P. W. A.; Rujopakarn, W.; Rumyantsev, V.; Rykoff, E. S.; Sharapov, D.; Starr, D.; Sunyaev, R. A.; Swan, H.; Tanvir, N. R.; Terra, F.; de Ugarte Postigo, A.; Vreeswijk, P. M.; Wilson, A. C.; Yost, S. A.; Yuan, F.

    2010-11-01

    Aims: With this paper we want to investigate the highly variable afterglow light curve and environment of gamma-ray burst (GRB) 060526 at z = 3.221. Methods: We present one of the largest photometric datasets ever obtained for a GRB afterglow, consisting of multi-color photometric data from the ultraviolet to the near infrared. The data set contains 412 data points in total to which we add additional data from the literature. Furthermore, we present low-resolution high signal-to-noise spectra of the afterglow. The afterglow light curve is modeled with both an analytical model using broken power law fits and with a broad-band numerical model which includes energy injections. The absorption lines detected in the spectra are used to derive column densities using a multi-ion single-component curve-of-growth analysis from which we derive the metallicity of the host of GRB 060526. Results: The temporal behaviour of the afterglow follows a double broken power law with breaks at t = 0.090 ± 0.005 and t = 2.401 ± 0.061 days. It shows deviations from the smooth set of power laws that can be modeled by additional energy injections from the central engine, although some significant microvariability remains. The broadband spectral-energy distribution of the afterglow shows no significant extinction along the line of sight. The metallicity derived from S ii and Fe ii of [S/H] = -0.57 ± 0.25 and [Fe/H] = -1.09 ± 0.24 is relatively high for a galaxy at that redshift but comparable to the metallicity of other GRB hosts at similar redshifts. At the position of the afterglow, no host is detected to F775W(AB) = 28.5 mag with the HST, implying an absolute magnitude of the host M(1500 Å) > -18.3 mag which is fainter than most long-duration hosts, although the GRB may be associated with a faint galaxy at a distance of 11 kpc. Based in part on observations obtained with the European Southern Observatory's Very Large Telescope under proposals 077.D-0661 (PI: Vreeswijk) and 177.A-0591

  17. Is GRB 100418A a Cosmic Twin of GRB 060614?

    Indian Academy of Sciences (India)

    Lan-Wei Jia; Hou-Jun Lü; Shu-Jin Hou; En-Wei Liang

    2011-03-01

    GRB 100418A is a long burst at = 0.624 without detection of associated supernova (SN).We present a detailed analysis on this event and discuss possible origins of its multi-wavelength emission. The temporal features of this event is similar to GRB 060614, a well-known nearby long GRB without SN association (possibly a Type I GRB), indicating that the two events may be cosmic twins. However, both the circumburst medium density and the GRB classification based on the gamma-ray energy and spectrum suggest that GRB 100418A would be a Type II GRB. These results make a great puzzle on the progenitors of this kind of events, if they belong to the same population.

  18. INTEGRAL and XMM-Newton observations of the low-luminosity and X-ray-rich burst GRB 040223

    International Nuclear Information System (INIS)

    GRB 040223 was observed by INTEGRAL and XMM-Newton. GRB 040223 has a peak flux of (1.6±0.13) x 10-8 ergs cm-2 s-1, a fluence of (4.4±0.4) x 10-7 ergs cm-2 and a steep photon power law index of -2.3±0.2, in the energy range 20-200 keV. The steep spectrum implies it is an X-ray-rich GRB with emission up to 200 keV and Epeak peak is x = -1.7±0.2, a temporal decay of t-0.75±0.25 and a large column density of 1.8 x 1022 cm-2. The luminosity-lag relationship was used to obtain a redshift z 0.1-0.02+0.04. The isotropic energy radiated in γ-rays and X-ray luminosity after 10 hours are factors of 1000 and 100 less than classical GRBs. GRB 040223 is consistent with the extrapolation of the Amati relation into the region that includes XRF 030723 and XRF 020903

  19. Polarimetric observations of GRB 011211

    OpenAIRE

    S. Covino(INAF - Oss. Astronomico di Brera); Lazzati, D.; Malesani, D.; Ghisellini, G.; Israel, G. L.; Stella, L.; Cimatti, A.; Di Serego, S.; Fiore, F.; Kawai, N.; S. Ortolani; Pasquini, L.; Ricker, G.; P. Saracco(INFN, Sezione di Genova); Tagliaferri, G.

    2002-01-01

    We present and discuss polarimetric observations performed with the VLT-UT3 (Melipal) on the afterglow of GRB 011211, ~35 hours after the burst onset. The observations yielded a 3-sigma upper limit of P

  20. The Afterglows of Swift-era Gamma-ray Bursts. I. Comparing pre-Swift and Swift-era Long/Soft (Type II) GRB Optical Afterglows

    Science.gov (United States)

    Kann, D. A.; Klose, S.; Zhang, B.; Malesani, D.; Nakar, E.; Pozanenko, A.; Wilson, A. C.; Butler, N. R.; Jakobsson, P.; Schulze, S.; Andreev, M.; Antonelli, L. A.; Bikmaev, I. F.; Biryukov, V.; Böttcher, M.; Burenin, R. A.; Castro Cerón, J. M.; Castro-Tirado, A. J.; Chincarini, G.; Cobb, B. E.; Covino, S.; D'Avanzo, P.; D'Elia, V.; Della Valle, M.; de Ugarte Postigo, A.; Efimov, Yu.; Ferrero, P.; Fugazza, D.; Fynbo, J. P. U.; Gålfalk, M.; Grundahl, F.; Gorosabel, J.; Gupta, S.; Guziy, S.; Hafizov, B.; Hjorth, J.; Holhjem, K.; Ibrahimov, M.; Im, M.; Israel, G. L.; Jeĺinek, M.; Jensen, B. L.; Karimov, R.; Khamitov, I. M.; Kiziloǧlu, Ü.; Klunko, E.; Kubánek, P.; Kutyrev, A. S.; Laursen, P.; Levan, A. J.; Mannucci, F.; Martin, C. M.; Mescheryakov, A.; Mirabal, N.; Norris, J. P.; Ovaldsen, J.-E.; Paraficz, D.; Pavlenko, E.; Piranomonte, S.; Rossi, A.; Rumyantsev, V.; Salinas, R.; Sergeev, A.; Sharapov, D.; Sollerman, J.; Stecklum, B.; Stella, L.; Tagliaferri, G.; Tanvir, N. R.; Telting, J.; Testa, V.; Updike, A. C.; Volnova, A.; Watson, D.; Wiersema, K.; Xu, D.

    2010-09-01

    We have gathered optical photometry data from the literature on a large sample of Swift-era gamma-ray burst (GRB) afterglows including GRBs up to 2009 September, for a total of 76 GRBs, and present an additional three pre-Swift GRBs not included in an earlier sample. Furthermore, we publish 840 additional new photometry data points on a total of 42 GRB afterglows, including large data sets for GRBs 050319, 050408, 050802, 050820A, 050922C, 060418, 080413A, and 080810. We analyzed the light curves of all GRBs in the sample and derived spectral energy distributions for the sample with the best data quality, allowing us to estimate the host-galaxy extinction. We transformed the afterglow light curves into an extinction-corrected z = 1 system and compared their luminosities with a sample of pre-Swift afterglows. The results of a former study, which showed that GRB afterglows clustered and exhibited a bimodal distribution in luminosity space, are weakened by the larger sample. We found that the luminosity distribution of the two afterglow samples (Swift-era and pre-Swift) is very similar, and that a subsample for which we were not able to estimate the extinction, which is fainter than the main sample, can be explained by assuming a moderate amount of line-of-sight host extinction. We derived bolometric isotropic energies for all GRBs in our sample, and found only a tentative correlation between the prompt energy release and the optical afterglow luminosity at 1 day after the GRB in the z = 1 system. A comparative study of the optical luminosities of GRB afterglows with echelle spectra (which show a high number of foreground absorbing systems) and those without, reveals no indication that the former are statistically significantly more luminous. Furthermore, we propose the existence of an upper ceiling on afterglow luminosities and study the luminosity distribution at early times, which was not accessible before the advent of the Swift satellite. Most GRBs feature

  1. Can the bump in the composite spectrum of GRB 910503 be an emission line feature of gamma-ray bursts?

    Institute of Scientific and Technical Information of China (English)

    Yi-Ping Qin; Fu-Wen Zhang

    2005-01-01

    Appearing in the composite spectral data of BATSE, EGRET and COMPTEL for GRB 910503, there is a bump at around 1600keV. We perform a statistical analysis on the spectral data, trying to find out if the bump could be accounted for by a blue-shifted and significantly broadened rest frame line due to the Doppler effect of an expanding fireball surface. We made an F-test and adopted previously proposed criteria. The study reveals that the criteria are well satisfied and the feature can be interpreted as the blue shifted 6.4 keV line. From the fit with this line taken into account, we find the Lorentz factor of this source to be Γ = 116+9-9 (at the 68% confident level,△X2 = 1) and the rest frame spectral peak energy to be EO,p= 2.96+0.24-0.18 keV. Although the existence of the emission line feature requires other independent tests to confirm, the analysis suggests that it is feasible to detect emission line features in the high energy range of GRB spectra when taking into account the Doppler effect of fireball expansion.

  2. Another short-burst host galaxy with an optically obscured high star formation rate: The case of GRB 071227

    International Nuclear Information System (INIS)

    We report on radio continuum observations of the host galaxy of the short gamma-ray burst 071227 (z = 0.381) with the Australia Telescope Compact Array. We detect the galaxy in the 5.5 GHz band with an integrated flux density of F ν = 43 ± 11 μJy, corresponding to an unobscured star-formation rate of about 24 M ☉ yr–1, 40 times higher than what was found from optical emission lines. Among the ∼30 well-identified and studied host galaxies of short bursts this is the third case where the host is found to undergo an episode of intense star formation. This suggests that a fraction of all short-burst progenitors hosted in star-forming galaxies could be physically related to recent star formation activity, implying a relatively short merger timescale.

  3. Another short-burst host galaxy with an optically obscured high star formation rate: The case of GRB 071227

    Energy Technology Data Exchange (ETDEWEB)

    Nicuesa Guelbenzu, A.; Klose, S.; Kann, D. A.; Rossi, A.; Schmidl, S. [Thüringer Landessternwarte Tautenburg, Sternwarte 5, D-07778 Tautenburg (Germany); Michałowski, M. J.; McKenzie, M. R. G. [Scottish Universities Physics Alliance, Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh, EH9 3HJ (United Kingdom); Savaglio, S.; Greiner, J. [Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstraße, D-85748 Garching (Germany); Hunt, L. K. [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy); Gorosabel, J. [Instituto de Astrofísica de Andalucía, Consejo Superior de Investigaciones Científicas (IAA-CSIC), Glorieta de la Astronomía s/n, E-18008 Granada (Spain); Palazzi, E. [INAF-IASF Bologna, Via Gobetti 101, I-40129 Bologna (Italy)

    2014-07-01

    We report on radio continuum observations of the host galaxy of the short gamma-ray burst 071227 (z = 0.381) with the Australia Telescope Compact Array. We detect the galaxy in the 5.5 GHz band with an integrated flux density of F {sub ν} = 43 ± 11 μJy, corresponding to an unobscured star-formation rate of about 24 M {sub ☉} yr{sup –1}, 40 times higher than what was found from optical emission lines. Among the ∼30 well-identified and studied host galaxies of short bursts this is the third case where the host is found to undergo an episode of intense star formation. This suggests that a fraction of all short-burst progenitors hosted in star-forming galaxies could be physically related to recent star formation activity, implying a relatively short merger timescale.

  4. The Spectral SN-GRB Connection: Systematic Spectral Comparisons between Type Ic Supernovae, broad-lined Type Ic Supernovae with and without Gamma-Ray Bursts

    CERN Document Server

    Modjaz, Maryam; Bianco, Federica B; Graur, Or

    2015-01-01

    We present the first systematic investigation of spectral properties of 17 Type Ic Supernovae (SNe Ic), 10 broad-lined SNe Ic (SNe Ic-bl) without observed Gamma-Ray Bursts (GRBs) and 10 SNe Ic-bl with GRBs (SN-GRBs) as a function of time in order to probe their explosion conditions and progenitors. We analyze a total of 396 spectra, which were drawn from published spectra of individual SNe as well as from the densely time-sampled spectra data of Modjaz et al. (2014). In order to quantify the diversity of the SN spectra as a function of SN subtype, we construct average spectra of SNe Ic, SNe Ic-bl without GRBs and SNe Ic-bl with GRBs, along with standard deviation and maximum deviation contours. We find that SN~1994I is not a typical SN Ic, in contrast to common belief, while the spectra of SN 1998bw/GRB 980425 are representative of mean spectra of SNe Ic-bl. We measure the ejecta absorption and width velocities (as traced by FeII 5169) and find that SNe Ic-bl with GRBs, on average, have quantifiably higher ab...

  5. A minor body falling onto a neutron star as an explanation for the unusual gamma-ray burst GRB 101225A

    CERN Document Server

    Campana, S; D'Avanzo, P; Panagia, N; Rossi, E M; Della Valle, M; Tagliaferri, G; Antonelli, L A; Covino, S; Ghirlanda, G; Ghisellini, G; Melandri, A; Pian, E; Salvaterra, R; Cusumano, G; D'Elia, V; Fugazza, D; Palazzi, E; Sbarufatti, B; Vergani, S D

    2011-01-01

    The tidal disruption of a solar mass star around a supermassive black hole has been extensively studied analytically and numerically. In these events the star develops into an elongated banana-shaped structure. After completing an eccentric orbit, the bound debris fall onto the black hole, forming an accretion disk and emitting radiation. The same process may occur on planetary scales, if a minor body orbits too close to its star. In the Solar System, comets fall directly onto our Sun or onto planets. If the star is a compact object, the minor body can become tidally disrupted. Indeed, one of the first mechanisms invoked to produce strong gamma-ray emission involved accretion of comets onto neutron stars in our Galaxy. Here we report that the peculiarities of the `Christmas' gamma-ray burst (GRB 101225A) can be explained by a tidal disruption event of a minor body around a Galactic isolated neutron star. This result would indicate either that minor bodies can be captured by compact stellar remnants more frequ...

  6. Correlation between the Peak Spectral Energy of Gamma-Ray Bursts and the Peak Luminosity of the Underlying Supernovae: Implication for the Nature of GRB-SN Connection

    CERN Document Server

    Li, L X

    2006-01-01

    In this paper we present a correlation between the peak spectral energy of gamma-ray bursts (GRBs) and the peak bolometric luminosity of the underlying supernovae (SNe), based on a sample of four pairs of GRBs-SNe with spectroscopically confirmed connection. Combining it with the well-known relation between the peak spectral energy and the isotropic equivalent energy of GRBs, we obtain an upper limit on the isotropic energy of GRBs, which is \\approx 10^{52} erg (L_{SN,peak}/10^{43} erg s^{-1})^{10}, where L_{SN,peak} is the peak bolometric luminosity of the SNe. Our results suggest that the critical parameter determining the GRB-SN connection is the peak luminosity of SNe, rather than the feature of the SN spectra and/or the SN explosion energy as commonly hypothesized. Since it is generally believed that the peak luminosity of SNe powered by radioactive decays is related to the amount of 56Ni produced in the SN explosion, the mass of 56Ni may be a key physical factor for understanding the nature of GRBs and ...

  7. The very red afterglow of GRB 000418: Further evidence for dust extinction in a gamma-ray burst host galaxy

    DEFF Research Database (Denmark)

    Klose, S.; Stecklum, B.; Masetti, N.; Pian, E.; Palazzi, E.; Henden, A.A.; Vrba, F.J.; Hartmann, D.H.; Fischer, O.; Gorosabel, J.; Sanchéz-Fernandéz, C.; Butler, D.; Ott, Th.; Hippler, S.; Kasper, M.; Weiss, R.; Castro-Tirado, A.J.; Greiner, J.; Bartolini, C.; Guarnieri, A.; Piccioni, A.; Benetti, S.; Ghinassi, F.; Magazzú, A.; Hurley, K.; Cline, T.; Trombka, J.; McClanahan, T.; Starr, R.; Goldsten, J.; Gold, R.; Mazets, E.; Golenetskii, S.; Noeske, K.; Papaderos, P.; Vreeswijk, P.M.; Tanvir, N.; Oscoz, A.; Muñoz, J.A.; Sastro Cerón, J.M.

    2000-01-01

    be R = 23.9 and an intrinsic afterglow decay slope of 1.22. The afterglow was very red with R-K approximate to 4 mag. The observations can be explained by an adiabatic, spherical fireball solution and a heavy reddening due to dust extinction in the host galaxy. This supports the picture that (long......) bursts are associated with events in star-forming regions....

  8. GRB 090323 and GRB 090328: two long high-energy GRBs detected with Fermi

    OpenAIRE

    Bissaldi, Elisabetta; Collaboration, for the Fermi GBM

    2010-01-01

    We present the analysis of two long Gamma-Ray Bursts, GRB 090323 and GRB 090328, which triggered the Fermi Gamma-Ray Burst Monitor (GBM) and generated an Autonomous Repoint Request to the Fermi Large Area Telescope. The GBM light curves show multi-peaked structures for both events. Here, we present time-integrated and time-resolved burst spectra fitted with different models by the GBM detectors.

  9. Study of WATCH GRB error boxes

    DEFF Research Database (Denmark)

    Gorosabel, J.; Castro-Tirado, A. J.; Lund, Niels;

    1995-01-01

    We have studied the first WATCH GRB Catalogue ofγ-ray Bursts in order to find correlations between WATCH GRB error boxes and a great variety of celestial objects present in 33 different catalogues. No particular class of objects has been found to be significantly correlated with the WATCH GRBs....

  10. The Swift GRB Mission

    Science.gov (United States)

    Gehrels, Neil; Chincarini, Guido

    2004-01-01

    Swift is a MIDEX mission that is in development for launch in October 2004. It is a multiwavelength transient observatory for GRB astronomy. The goals of the mission are to determine the origin of GRBs and their afterglows and use bursts to probe the early Universe. A wide-field gamma-ray camera will detect mare than 100 GRBs per year to -3 times fainter than BATSE. Sensitive narrow-field X-ray and UV/optical telescopes will be pointed at the burst location in 20 to 75 sec by an autonomously controlled spacecraft. Far each burst, aresec positions will be determined and optical/UV/X-ray/gamma-say spectrophotometry performed. Measurements of redshift will be made for many burstes. The instrumentation is a combination of superb existing flight-spare hardware and design from XMM and Spectrum-X/JET-X contributed by collaborators in the UK and Italy and development of a coded-aperture camera with a large-area (approx. 0.5 square meter) CdZnTe detector array. Key components of the mission are vigorous follow-up and outreach programs to engage the astronomical community and public in Swift. The talk vi11 describe the mission statue and give a summary of plans for GRB operations. It is likely that Swift will have just been launched at the time of the conference.

  11. A NEARBY GAMMA-RAY BURST HOST PROTOTYPE FOR z ∼ 7 LYMAN-BREAK GALAXIES: SPITZER-IRS AND X-SHOOTER SPECTROSCOPY OF THE HOST GALAXY OF GRB 031203

    International Nuclear Information System (INIS)

    Gamma-ray burst (GRB) host galaxies have been studied extensively in optical photometry and spectroscopy. Here we present the first mid-infrared spectrum of a GRB host, HG 031203. It is one of the nearest GRB hosts at z = 0.1055, allowing both low- and high-resolution spectroscopy with the Spitzer Infrared Spectrograph (IRS). Medium-resolution UV to K-band spectroscopy with the X-shooter spectrograph on the Very Large Telescope is also presented, along with Spitzer IRAC and MIPS photometry, as well as radio and submillimeter observations. These data allow us to construct a UV to radio spectral energy distribution with almost complete spectroscopic coverage from 0.3 to 35 μm of a GRB host galaxy for the first time, potentially valuable as a template for future model comparisons. The IRS spectra show strong, high-ionization fine structure line emission indicative of a hard radiation field in the galaxy—in particular the [S IV]/[S III] and [Ne III]/[Ne II] ratios—suggestive of strong ongoing star formation and a very young stellar population. The absence of any polycyclic aromatic hydrocarbon emission supports these conclusions, as does the probable hot peak dust temperature, making HG 031203 similar to the prototypical blue compact dwarf galaxy (BCD), II Zw 40. The selection of HG 031203 via the presence of a GRB suggests that it might be a useful analog of very young star-forming galaxies in the early universe, and hints that local BCDs may be used as more reliable analogs of star formation in the early universe than typical local starbursts. We look at the current debate on the ages of the dominant stellar populations in z ∼ 7 and z ∼ 8 galaxies in this context. The nebular line emission is so strong in HG 031203 that at z ∼ 7, it can reproduce the spectral energy distributions of z-band dropout galaxies with elevated IRAC 3.6 and 4.5 μm fluxes without the need to invoke a 4000 Å break. Indeed, photometry of HG 031203 shows elevation of the broadband V

  12. Hubble Space Telescope and Palomar Imaging of GRB 990123 Implications for the Nature of Gamma-Ray Bursts and Their Hosts

    CERN Document Server

    Fruchter, A S; Metzger, M R; Sahu, K C; Petro, L; Livio, M; Ferguson, H; Pian, E; Hogg, D W; Galama, T J; Gull, T R; Kouveliotou, C; Macchetto, D; Van Paradijs, J; Pedersen, H J; Smette, A; Fruchter, Andrew S.; Metzger, Mark R.; Sahu, Kailash C.; Petro, Larry; Livio, Mario; Ferguson, Henry; Pian, Elena; Hogg, David W.; Galama, Titus; Gull, Theodore R.; Kouveliotou, Chryssa; Macchetto, Duccio; Paradijs, Jan van; Pedersen, Holger; Smette, Alain

    1999-01-01

    We report on deep HST and Palomar optical images of the field of GRB~990123, obtained on 8 and 9 February 1999. We find that the optical transient (OT) associated with GRB~990123 is located on an irregular galaxy, with magnitude $V=24.20 \\pm 0.15$. The deep metal absoption lines seen in the spectrum of the OT, along with the low probablility of a chance superposition, lead us to conclude that this galaxy is the host of the GRB. The OT is projected within the $\\sim1''$ visible stellar field of the host, nearer the edge than the center. We cannot, on this basis, rule out the galactic nucleus as the site of the GRB, since the unusual morphology of the host may be the result of an ongoing galactic merger, but our demonstration that this host galaxy has extremely blue optical to infrared colors more strongly supports an association between GRBs and star formation. We find that the OT magnitude on 1999 Feb 9.05, $V = 25.45 \\pm 0.15$, is about 1.5 mag fainter than expected from extrapolation of the decay rate found ...

  13. The unusual gamma-ray burst GRB 101225A from a helium star/neutron star merger at redshift 0.33

    Czech Academy of Sciences Publication Activity Database

    Thöne, C.C.; Postigo, A. de U.; Fryer, C.L.; Page, K.L.; Gorosabel, J.; Aloy, M.A.; Perley, D.A.; Kouveliotou, C.; Janka, H.T.; Mimica, P.; Racusin, J.L.; Krimm, H.; Cummings, J.; Oates, S.R.; Holland, S.T.; Siegel, M.H.; De Pasquale, M.; Sonbas, E.; Im, M.; Park, W.-K.; Kann, D.A.; Guziy, S.; Garcia, H.L.; Llorente, A.; Bundy, K.; Choi, C.; Jeong, H.; Korhonen, H.; Kubánek, Petr; Lim, J.; Moskvitin, A.; Munoz-Darias, T.; Pak, S.; Parrish, I.

    2011-01-01

    Roč. 480, č. 7375 (2011), 72-74. ISSN 0028-0836 Institutional research plan: CEZ:AV0Z10100502 Keywords : GRB Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 36.280, year: 2011 http://www.nature.com/nature/journal/v480/n7375/full/nature10611.html

  14. A Trio of GRB-SNe: GRB 120729A, GRB 130215A / SN 2013ez and GRB 130831A / SN 2013fu

    CERN Document Server

    Cano, Z; Pozanenko, A; Butler, N; Thone, C C; Guidorzi, C; Kruhler, T; Gorosabel, J; Jakobsson, P; Leloudas, G; Malesani, D; Hjorth, J; Melandri, A; Mundell, C; Wiersema, K; D'Avanzo, P; Schulze, S; Gomboc, A; Johansson, A; Zheng, W; Kann, D A; Knust, F; Varela, K; Akerlof, C W; Bloom, J; Burkhonov, O; Cooke, E; de Diego, J A; Dhungana, G; Farina, C; Ferrante, F V; Flewelling, H A; Fox, O D; Fynbo, J; Gehrels, N; Georgiev, L; Gonzalez, J J; Greiner, J; Guver, T; Hartoog, O; Hatch, N; Jelinek, M; Kehoe, R; Klose, S; Klunko, E; Kopac, D; Kutyrev, A; Krugl, Y; Lee, W H; Levan, A; Linkov, V; Matkin, A; Minikulov, N; Molotov, I; Prochaska, J Xavier; Richer, M G; Roman-Zuniga, C G; Rumyantsev, V; Sanchez-Ramirez, R; Steele, I; Tanvir, N R; Volnova, A; Watson, A M; Xu, D; Yuan, F

    2014-01-01

    We present optical and near-infrared (NIR) photometry for three gamma-ray burst supernovae (GRB-SNe): GRB 120729A, GRB 130215A / SN 2013ez and GRB 130831A / SN 2013fu. In the case of GRB 130215A / SN 2013ez, we also present optical spectroscopy at t-t0=16.1 d, which covers rest-frame 3000-6250 Angstroms. Based on Fe II (5169) and Si (II) (6355), our spectrum indicates an unusually low expansion velocity of 4000-6350 km/s, the lowest ever measured for a GRB-SN. Additionally, we determined the brightness and shape of each accompanying SN relative to a template supernova (SN 1998bw), which were used to estimate the amount of nickel produced via nucleosynthesis during each explosion. We find that our derived nickel masses are typical of other GRB-SNe, and greater than those of SNe Ibc that are not associated with GRBs. For GRB 130831A / SN 2013fu, we use our well-sampled R-band light curve (LC) to estimate the amount of ejecta mass and the kinetic energy of the SN, finding that these too are similar to other GRB-...

  15. GRB 130427A: A Nearby Ordinary Monster

    Science.gov (United States)

    Maselli, A.; Melandri, A.; Nava, L.; Mundell, C. G.; Kawai, N.; Campana, S.; Covino, S.; Cummings, J. R.; Cusumano, G.; Evans, P. A.; Ghirlander, G.; Ghisellini, G.; Guidorzi, C.; Kobayashi, S.; Kuin, P.; La Parola, V.; Mangano, V.; Oates, S.; Barthelmy, S.; Gehrels, N.; Marshall, F.; Wiegand, B.

    2014-01-01

    Long-duration gamma-ray bursts (GRBs) are an extremely rare outcome of the collapse of massive stars and are typically found in the distant universe. Because of its intrinsic luminosity (L approx. 3 x 10(exp 53) ergs/s and its relative proximity (z = 0.34), GRB 130427A reached the highest fluence observed in the gamma-ray band. Here, we present a comprehensive multiwavelength view of GRB 130427A with Swift, the 2-meter Liverpool and Faulkes telescopes, and by other ground-based facilities, highlighting the evolution of the burst emission from the prompt to the afterglow phase. The properties of GRB 130427A are similar to those of the most luminous, high-redshift GRBs, suggesting that a common central engine is responsible for producing GRBs in both the contemporary and the early universe and over the full range of GRB isotropic energies.

  16. GRB 130427A: a Nearby Ordinary Monster

    CERN Document Server

    Maselli, A; Nava, L; Mundell, C G; Kawai, N; Campana, S; Covino, S; Cummings, J R; Cusumano, G; Evans, P A; Ghirlanda, G; Ghisellini, G; Guidorzi, C; Kobayashi, S; Kuin, P; La Parola, V; Mangano, V; Oates, S; Sakamoto, T; Serino, M; Virgili, F; Zhang, B -B; Barthelmy, S; Beardmore, A; Bernardini, M G; Bersier, D; Burrows, D; Calderone, G; Capalbi, M; Chiang, J; D'Avanzo, P; D'Elia, V; De Pasquale, M; Fugazza, D; Gehrels, N; Gomboc, A; Harrison, R; Hanayama, H; Japelj, J; Kennea, J; Kopac, D; Kouveliotou, C; Kuroda, D; Levan, A; Malesani, D; Marshall, F; Nousek, J; O'Brien, P; Osborne, J P; Pagani, C; Page, K L; Page, M; Perri, M; Pritchard, T; Romano, P; Saito, Y; Sbarufatti, B; Salvaterra, R; Steele, I; Tanvir, N; Vianello, G; Weigand, B; Wiersema, K; Yatsu, Y; Yoshii, T; Tagliaferri, G

    2014-01-01

    Long-duration Gamma-Ray Bursts (GRBs) are an extremely rare outcome of the collapse of massive stars, and are typically found in the distant Universe. Because of its intrinsic luminosity ($L\\sim 3 \\times 10^{53}$ erg s$^{-1}$) and its relative proximity ($z=0.34$), GRB 130427A was a unique event that reached the highest fluence observed in the gamma-ray band. Here we present a comprehensive multiwavelength view of GRB 130427A with Swift, the 2-m Liverpool and Faulkes telescopes and by other ground-based facilities, highlighting the evolution of the burst emission from the prompt to the afterglow phase. The properties of GRB 130427A are similar to those of the most luminous, high-redshift GRBs, suggesting that a common central engine is responsible for producing GRBs in both the contemporary and the early Universe and over the full range of GRB isotropic energies.

  17. GRB 050319

    DEFF Research Database (Denmark)

    Fynbo, J.P.U; Hjorth, J.; Jakobsson, P.; Møller, P; Naranen, J

    2005-01-01

    "Using ALFOSC on the Nordic Optical Telescope (NOT) we have obtained spectra of the afterglow of GRB 050319 (GCN 3116, 3117) on 2005, March 20 UT. We find several absorption features, including strong Lyman-alpha, OI+SiII, SiIV and CIV, corresponding to a redshift of z=3.24."......"Using ALFOSC on the Nordic Optical Telescope (NOT) we have obtained spectra of the afterglow of GRB 050319 (GCN 3116, 3117) on 2005, March 20 UT. We find several absorption features, including strong Lyman-alpha, OI+SiII, SiIV and CIV, corresponding to a redshift of z=3.24."...

  18. On the nature of the short-duration GRB 050906

    Science.gov (United States)

    Levan, A. J.; Tanvir, N. R.; Jakobsson, P.; Chapman, R.; Hjorth, J.; Priddey, R. S.; Fynbo, J. P. U.; Hurley, K.; Jensen, B. L.; Johnson, R.; Gorosabel, J.; Castro-Tirado, A. J.; Jarvis, M.; Watson, D.; Wiersema, K.

    2008-02-01

    We present deep optical and infrared (IR) observations of the short-duration GRB 050906. Although no X-ray or optical/IR afterglow was discovered to deep limits, the error circle of the gamma-ray burst (GRB) (as derived from the Swift Burst Alert Telescope, or BAT) is unusual in containing the relatively local starburst galaxy IC328. This makes GRB 050906 a candidate burst from a soft gamma-ray repeater (SGR), similar to the giant flare from SGR 1806-20. The probability of chance alignment of a given BAT position with such a galaxy is small (levan@warwick.ac.uk

  19. Highly Luminous Supernovae associated with Gamma-Ray Bursts I.: GRB 111209A/SN 2011kl in the Context of Stripped-Envelope and Superluminous Supernovae

    CERN Document Server

    Kann, D A; E., F Olivares; Klose, S; Rossi, A; Perley, D A; Krühler, T; Greiner, J; Guelbenzu, A Nicuesa; Elliott, J; Knust, F; Filgas, R; Pian, E; Mazzali, P; Fynbo, J P U; Leloudas, G; Afonso, P M J; Delvaux, C; Graham, J F; Rau, A; Schmidl, S; Schulze, S; Tanga, M; Updike, A C; Varela, K

    2016-01-01

    We address the question whether GRB 111209A was a special event beyond its extreme duration alone, and whether it is a classical GRB or another kind of high-energy transient. Furthermore, we place SN 2011kl into the context of large samples of SNe, addressing in more detail the question of whether it could be radioactively powered. We present afterglow photometry obtained in seven bands with the GROND imager as well as in further seven bands with the UVOT telescope on-board \\emph{Swift}. The light curve is analysed by multi-band modelling and joint fitting with power-laws and broken power-laws. We model SN 2011kl using SN 1998bw as a template and derive a bolometric light curve including near-infrared data. We compare the optical afterglow and the properties of SN 2011kl to large ensembles we have analysed in earlier works, additional GRB-SNe analysed here, as well as literature results on stripped-envelope and superluminous supernovae. We find a strong, chromatic rebrightening event at $\\approx0.8$ days afte...

  20. GRB 140606B / iPTF14bfu: Detection of shock-breakout emission from a cosmological gamma-ray burst?

    CERN Document Server

    Cano, Z; Perley, D; Kruhler, T; Margutti, R; Friis, M; Malesani, D; Jakobsson, P; Fynbo, J P U; Gorosabel, J; Hjorth, J; Sanchez-Ramirez, R; Schulze, S; Tanvir, N R; Thone, C C; Xu, D

    2015-01-01

    We present optical and near-infrared photometry of GRB 140606B ($z=0.384$), and optical photometry and spectroscopy of its associated supernova (SN). The bolometric properties of the SN are: a nickel mass of M$_{\\rm Ni}$=0.4$\\pm$0.2 M$_{\\odot}$, an ejecta mass of M$_{\\rm ej}$=5$\\pm$2 M$_{\\odot}$, and a kinetic energy of E$_{\\rm K}$=2$\\pm1\\times10^{52}$ erg. The uncertain value of M$_{\\rm Ni}$ is primarily due to the poorly constrained rest-frame extinction ($E(B-V)_{\\rm rest}$=0.16$\\pm$0.14 mag). The photospheric velocity of the SN near maximum light is $v_{\\rm ph}\\approx$20,000 km/s. The photospheric velocity and bolometric properties are fully consistent with the statistical averages determined for other GRB-SNe. However, in terms of its $\\gamma$-ray emission, GRB 140606B is an outlier of the Amati relation, and occupies the same region as low-luminosity ($ll$) and short GRBs. The $\\gamma$-ray emission in $ll$GRBs is thought to arise, at least in some events, from a shock-breakout (SBO), rather than from a ...

  1. GRB 060605: RTT150 optical observations

    Science.gov (United States)

    Khamitov, I.; Saygac, A. T.; Aslan, Z.; Kiziloglu, U.; Gogus, E.; Alis, S.; Onal, O.; Burenin, R.; Pavlinsky, M.; Sunyaev, R.; Bikmaev, I.; Sakhibullin, N.

    2006-06-01

    We observed the field around the position of the optical counterpart (Rykoff et al. GCN5220, Page et al., GCN5221) of GRB060605 (Swift trigger 213630) with the Russian-Turkish 1.5-m telescope (RTT150, Bakirlitepe, TUBITAK National Observatory, Turkey), at the beginning of June 07, about 31.1 hours after the burst. A series of frames was taken in R band with TFOSC. The afterglow is detected on combined image. http://www.tug.tubitak.gov.tr/~irekk/grb/grb060605/GRB060605_0607_RTT150.JPG Using USNO-B1 star (RA=21:28:40.26, DEC=-06:03:44.5, R2MAG=15.37) we estimate the following R magnitude for the OT: t-t0 m_R err 31.1 23.0 0.2 Using all data (Khamitov et al., GCN5224) we estimate the power-law decay index in R as -1.7+-0.02, which did not changed since ~5.6 hours after the burst. Our R lightcurve can be found at: http://www.tug.tubitak.gov.tr/~irekk/grb/grb060605/GRB060605_lc0607.jpg This message may be cited.

  2. The GRB early optical flash from internal shock: application to GRB990123, GRB041219a and GRB060111b

    CERN Document Server

    Wei, D M

    2006-01-01

    With the successful launch of the Swift Gamma-Ray Burst Explorer, people expected the prompt optical flash like GRB990123 would be easily detected. However the fact that early optical flash have not been detected for a number of GRBs indicates the reverse shock must be suppressed. Here we explore the possibility that the optical flash may arise from the internal shock. We find that, under certain circumstance, the optical flash of GRB990123 and GRB060111b can really be explained by the internal shock. For GRB041219a, the prompt optical emission was correlated with the gamma-ray emission, we explain this feature also in the internal shock scenario, the optical emission is the low energy extension of the gamma-ray emission, and we can restrict its redshift $z\\sim 0.2$. As for GRB050904, we have shown in previous paper that the optical flash was produced by synchrotron radiation and the X-ray flare was produced by the synchrotron-self-Compton mechanism. Therefore we conclude that the early optical flash of GRBs ...

  3. Gamma Ray Bursts and their Optical Counterparts

    International Nuclear Information System (INIS)

    Gamma Ray Bursts (GRB) have been discovered 38 years ago and still remain one of the most intriguing puzzles of astrophysics. In this paper we remind briefly the history of GRB studies and review the current experimental evidence with the emphasis on GRB optical counterparts. At the end we introduce '' π of the Sky '' project designed to catch prompt optical emission from GRB sources. (author)

  4. Calibration and Simulation of the GRB trigger detector of the Ultra Fast Flash Observatory

    DEFF Research Database (Denmark)

    Huang, M.-H.A.; Ahmad, S.; Barrillon, P.;

    2013-01-01

    The UFFO (Ultra-Fast Flash Observatory) is a GRB detector on board the Lomonosov satellite, to be launched in 2013. The GRB trigger is provided by an X-ray detector, called UBAT (UFFO Burst Alarm & Trigger Telescope), which detects X-rays from the GRB and then triggers to determine the direction ...

  5. Hyper-accreting black hole as GRB central engine. I: Baryon loading in GRB jets

    OpenAIRE

    Lei, Wei-Hua; Zhang, Bing; Liang, En-Wei

    2012-01-01

    A hyper-accreting stellar-mass black hole has been long speculated as the best candidate of central engine of gamma-ray bursts (GRBs). Recent rich observations of GRBs by space missions such as Swift and Fermi pose new constraints on GRB central engine models. In this paper, we study the baryon loading processes of a GRB jet launched from a black hole central engine. We consider a relativistic jet powered by $\

  6. The Ultra-Fast Flash Observatory’s space GRB mission and science

    DEFF Research Database (Denmark)

    Lim, H.; Ahmad, S.; Barrillon, P.;

    2012-01-01

    Abstract. The Ultra-Fast Flash Observatory (UFFO) is a space mission to detect the early moments of an explosion from Gamma-ray bursts (GRBs), thus enhancing our understanding of the GRB mechanism. It consists of the UFFO Burst & Trigger telescope (UBAT) for the recognition of GRB positions using...

  7. GRB 080913 at redshift 6.7

    CERN Document Server

    Greiner, J; Fynbo, J P U; Rossi, A; Schwarz, R; Klose, S; Savaglio, S; Tanvir, N R; McBreen, S; Totani, T; Zhang, B B; Wu, X F; Watson, D; Barthelmy, S D; Beardmore, A P; Ferrero, P; Gehrels, N; Kann, D A; Kawai, N; Yoldas, A Kuepcue; Mészáros, P; Milvang-Jensen, B; Oates, S R; Pierini, D; Schady, P; Toma, K; Vreeswijk, P M; Yoldas, A; Zhang, B; Afonso, P; Aoki, K; Burrows, D N; Clemens, C; Filgas, R; Haiman, Z; Hartmann, D H; Hasinger, G; Hjorth, J; Jehin, E; Levan, A J; Liang, E W; Malesani, D; Pyo, T -S; Schulze, S; Szokoly, G; Terada, H; Wiersema, K

    2008-01-01

    We report on the detection by Swift of GRB 080913, and subsequent optical/near-infrared follow-up observations by GROND which led to the discovery of its optical/NIR afterglow and the recognition of its high-z nature via the detection of a spectral break between the i' and z' bands. Spectroscopy obtained at the ESO-VLT revealed a continuum extending down to lambda = 9400 A, and zero flux for 7500 A < lambda<9400 A, which we interpret as the onset of a Gunn-Peterson trough at z=6.695+-0.025 (95.5% conf. level), making GRB 080913 the highest redshift GRB to date, and more distant than the highest-redshift QSO. We note that many redshift indicators which are based on promptly available burst or afterglow properties have failed for GRB 080913. We report on our follow-up campaign and compare the properties of GRB 080913 with bursts at lower redshift. In particular, since the afterglow of this burst is fainter than typical for GRBs, we show that 2m-class telescopes can identify most high-redshift GRBs.

  8. GRB Prompt Optical Observations by Master and Lomonosov

    Science.gov (United States)

    Gorbovskoy, Evgeny

    We present the results of the prompt, early and afterglow optical observations of five γ-ray bursts (GRBs): GRB 100901A, GRB 100902A, GRB 100905A, GRB 100906A and GRB 101020A. These observations were made with the Mobile Astronomical System of TElescope-Robots in Russia (MASTER-II Net), the 1.5-m telescope of the Sierra Nevada Observatory and the 2.56-m Nordic Optical Telescope. For two sources, GRB 100901A and GRB 100906A, we detected optical counterparts and obtained light curves starting before the cessation of γ-ray emission, at 113 and 48 s after the trigger, respectively. Observations of GRB 100906A were conducted in two polarizing filters. Observations of the other three bursts gave the upper limits on the optical flux; their properties are briefly discussed. A more detailed analysis of GRB 100901A and GRB 100906A, supplemented by Swift data, provides the following results and indicates different origins for the prompt optical radiation in the two bursts. The light-curve patterns and spectral distributions suggest that there is a common production site for the prompt optical and high-energy emission in GRB 100901A. The results of the spectral fits for GRB 100901A in the range from optical to X-ray favour power-law energy distributions and a consistent value of the optical extinction in the host galaxy. GRB 100906A produced a smoothly peaking optical light curve, suggesting that the prompt optical radiation in this GRB originated in a front shock. This is supported by a spectral analysis. We have found that the Amati and Ghirlanda relations are satisfied for GRB 100906A. We obtain an upper limit on the value of the optical extinction on the host of GRB 100906A. Also we consider prompt observation of dark gamma ray bursts for which on very widefield cameras MASTER-VWF and MASTER-II telescopes upper limits were received. We represent SHOCK experiment onboard the spacecraft Lomonosov.

  9. ALMA SUBMILLIMETER CONTINUUM IMAGING OF THE HOST GALAXIES OF GRB 021004 AND GRB 080607

    International Nuclear Information System (INIS)

    We report 345 GHz continuum observations of the host galaxies of gamma-ray bursts (GRBs) 021004 and 080607 at z > 2 using the Atacama Large Millimeter/Submillimeter Array (ALMA) in Cycle 0. Of the two bursts, GRB 021004 is one of the few GRBs that originate in a Lyman limit host, while GRB 080607 is classified as a 'dark burst' and its host galaxy is a candidate of dusty star-forming galaxy at z ∼ 3. With an order of magnitude improvement in the sensitivities of the new imaging searches, we detect the host galaxy of GRB 080607 with a flux of S345 = 0.31 ± 0.09 mJy and a corresponding infrared luminosity of LIR = (2.4-4.5) × 1011 L☉. However, the host galaxy of GRB 021004 remains undetected and the ALMA observations allow us to place a 3σ upper limit of LIR 11 L☉ for the host galaxy. The continuum imaging observations show that the two galaxies are not ultraluminous infrared galaxies, but are at the faintest end of the dusty galaxy population that gives rise to the submillimeter extragalactic background light. The derived star formation rates of the two GRB host galaxies are less than 100 M☉ yr–1, which are broadly consistent with optical measurements. The result suggests that the large extinction (AV ∼ 3) in the afterglow of GRB 080607 is confined along its particularly dusty sight line, and not representative of the global properties of the host galaxy.

  10. Could the GRB-Supernovae GRB 031203 and XRF 060218 be Cosmic Twins?

    CERN Document Server

    Feng, Lu

    2009-01-01

    The gamma-ray burst (GRB) / X-ray flash (XRF) events GRB 031203, discovered by INTEGRAL, and XRF 060218, discovered by Swift, represent two of only five GRB-SNe with optical spectroscopic confirmation of their SN components. Yet their observed high-energy properties offer a sharp contrast: While GRB 031203 was detected as a short 40-s burst with a spectrum peaking at E_peak > 190 keV, XRF 060218 was a T_90 ~ 2100-s long, smoothly-evolving burst with peak energy E_peak = 4.9 keV. At the same time, the properties of the two expanding dust-scattered X-ray halos observed in a fast-response XMM-Newton observation of GRB 031203 reveal that this event was accompanied by an "X-ray blast" with fluence comparable to or greater than that of the prompt gamma-ray event. Taking this observation as our starting point, we investigate the likely properties of the X-ray blast from GRB 031203 via detailed modeling of the XMM data, discovering a third halo due to scattering off a more distant dust sheet at d_3 = 9.94 +/- 0.39 kp...

  11. The GRB/XRF-SN Association

    CERN Document Server

    Dar, Arnon

    2004-01-01

    There is mounting evidence that long duration gamma ray bursts (GRBs) and X-ray flashes (XRFs) are produced by highly relativistic and narrowly collimated jets ejected in core collapse supernova (SN) explosions akin to SN 1998bw. We review the history of the GRB-SN association idea and its observational verification. We summarize the present evidence for a GRB/XRF-SN association. We comment on the possibility that most, perhaps all, SN explosions produce GRBs, including SNe of Type Ia which may produce short GRBs/XRFs. We list the major open questions that follow from a GRB/XRF-SN association. Possible uses of the GRB-SN association in cosmology are pointed out.

  12. GRB hosts through cosmic time. VLT/X-Shooter emission-line spectroscopy of 96 γ-ray-burst-selected galaxies at 0.1

    Science.gov (United States)

    Krühler, T.; Malesani, D.; Fynbo, J. P. U.; Hartoog, O. E.; Hjorth, J.; Jakobsson, P.; Perley, D. A.; Rossi, A.; Schady, P.; Schulze, S.; Tanvir, N. R.; Vergani, S. D.; Wiersema, K.; Afonso, P. M. J.; Bolmer, J.; Cano, Z.; Covino, S.; D'Elia, V.; de Ugarte Postigo, A.; Filgas, R.; Friis, M.; Graham, J. F.; Greiner, J.; Goldoni, P.; Gomboc, A.; Hammer, F.; Japelj, J.; Kann, D. A.; Kaper, L.; Klose, S.; Levan, A. J.; Leloudas, G.; Milvang-Jensen, B.; Nicuesa Guelbenzu, A.; Palazzi, E.; Pian, E.; Piranomonte, S.; Sánchez-Ramírez, R.; Savaglio, S.; Selsing, J.; Tagliaferri, G.; Vreeswijk, P. M.; Watson, D. J.; Xu, D.

    2015-09-01

    We present data and initial results from VLT/X-Shooter emission-line spectroscopy of 96 galaxies selected by long γ-ray bursts (GRBs) at 0.1 Swift and 76% are at 0.5 2 by ~0.4 dex. These properties of GRB hosts and their evolution with redshift can be understood in a cosmological context of star-forming galaxies and a picture in which the hosts' properties at low redshift are influenced by the tendency of GRBs to avoid the most metal-rich environments. Based on observations at ESO, Program IDs: 084.A-0260, 084.A-0303, 085.A-0009, 086.B-0954, 086.A-0533, 086.A-0874, 087.A-0055, 087.A-0451, 087.B-0737, 088.A-0051, 088.A-0644, 089.A-0067, 089.A-0120, 089.D-0256, 089.A-0868, 090.A-0088, 090.A-0760, 090.A-0825, 091.A-0342, 091.A-0703, 091.A-0877, 091.C-0934, 092.A-0076, 092.A-0124, 092.A-0231, 093.A-0069, 094.A-0593.Tables 1-4 and appendices are available in electronic form at http://www.aanda.orgThe reduced spectra are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/581/A125

  13. GRB 081007 AND GRB 090424: THE SURROUNDING MEDIUM, OUTFLOWS, AND SUPERNOVAE

    Energy Technology Data Exchange (ETDEWEB)

    Jin Zhiping; Covino, Stefano; Fugazza, Dino; Melandri, Andrea; Campana, Sergio; D' Avanzo, Paolo [INAF-Osservatorio Astronomico di Brera, via Emilio Bianchi 46, I-23807 Merate (Italy); Della Valle, Massimo [INAF-Osservatorio Astronomico di Capodimonte, Salita Moiariello, 16, I-80131 Napoli (Italy); Ferrero, Patrizia [Instituto de Astrofisica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain); Malesani, Daniele; Fynbo, Johan P. U.; Hjorth, Jens [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen O (Denmark); Pian, Elena [Scuola Normale Superiore di Pisa, Piazza dei Cavalieri 7, I-56126 Pisa (Italy); Salvaterra, Ruben [INAF-IASF Milano, via E. Bassini 15, I-20133 Milano (Italy); Bersier, David [Astrophysics Research Institute, Liverpool John Moores University, Egerton Wharf, Birkenhead CH41 1LD (United Kingdom); Cano, Zach [Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Reykjavik (Iceland); Castro-Tirado, Alberto J.; Gorosabel, Javier [Instituto de Astrofisica de Andalucia (IAA-CSIC), Glorieta de la Astronomia s/n, E-18008 Granada (Spain); Gomboc, Andreja [Mathematics and Physics, University of Ljubljana, Jadranska ulica 19, 1000 Ljubljana (Slovenia); Guidorzi, Cristiano [Department of Physics, University of Ferrara, via Saragat 1, I-44122 Ferrara (Italy); Haislip, Joshua B., E-mail: jin@pmo.ac.cn [Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599 (United States); and others

    2013-09-10

    We discuss the results of the analysis of multi-wavelength data for the afterglows of GRB 081007 and GRB 090424, two bursts detected by Swift. One of them, GRB 081007, also shows a spectroscopically confirmed supernova, SN 2008hw, which resembles SN 1998bw in its absorption features, while the maximum magnitude may be fainter, up to 0.7 mag, than observed in SN 1998bw. Bright optical flashes have been detected in both events, which allows us to derive solid constraints on the circumburst-matter density profile. This is particularly interesting in the case of GRB 081007, whose afterglow is found to be propagating into a constant-density medium, yielding yet another example of a gamma-ray burst (GRB) clearly associated with a massive-star progenitor which did not sculpt the surroundings with its stellar wind. There is no supernova component detected in the afterglow of GRB 090424, likely due to the brightness of the host galaxy, comparable to the Milky Way. We show that the afterglow data are consistent with the presence of both forward- and reverse-shock emission powered by relativistic outflows expanding into the interstellar medium. The absence of optical peaks due to the forward shock strongly suggests that the reverse-shock regions should be mildly magnetized. The initial Lorentz factor of outflow of GRB 081007 is estimated to be {Gamma} {approx} 200, while for GRB 090424 a lower limit of {Gamma} > 170 is derived. We also discuss the prompt emission of GRB 081007, which consists of just a single pulse. We argue that neither the external forward-shock model nor the shock-breakout model can account for the prompt emission data and suggest that the single-pulse-like prompt emission may be due to magnetic energy dissipation of a Poynting-flux-dominated outflow or to a dissipative photosphere.

  14. Radio Observations of GRB Host Galaxies

    CERN Document Server

    Stanway, E R; Davies, Luke J M

    2014-01-01

    We present 5.5 and 9.0 GHz observations of a sample of seventeen GRB host galaxies at 0.5GRB 100418A) likely due to lingering afterglow emission. We suggest that the previously-reported radio afterglow of GRB 100621A may instead be due to host galaxy flux. We see no strong evidence for redshift evolution in the typical star formation rate of GRB hosts, but note that the fraction of `dark' bursts with detections is higher than would be expected given constraints on the more typical long GRB population. We also determine the average radio-derived star formation rates of core collapse supernovae at comparable redshift, and show that these are still well below the limits obtained for GRB hosts, and show evidence for a rise in typical star formation rate with redshift in supernova hosts.

  15. Prompt GRB optical follow-up experiments

    Energy Technology Data Exchange (ETDEWEB)

    Park, H-S; Williams, G; Ables, E; Band, D; Barthelmy, S; Bionta, R; Cline, T; Gehrels, N; Hartmann, D; Hurley, K; Kippen, M; Nemiroff, R; Pereira, W; Porrata, R

    2000-11-13

    Gamma Ray Bursts (GRBs) are brief, randomly located, releases of gamma-ray energy from unknown celestial sources that occur almost daily. The study of GRBs has undergone a revolution in the past three years due to an international effort of follow-up observations of coordinates provided by Beppo/SAX and IPN GRB. These follow-up observations have shown that GRBs are at cosmological distances and interact with surrounding material as described by the fireball model. However, prompt optical counterparts have only been seen in one case and are therefore very rare or much dimmer than the sensitivity of the current instruments. Unlike later time afterglows, prompt optical measurements would provide information on the GRB progenitor. LOTIS is the very first automated and dedicated telescope system that actively utilizes the GRB Coordinates Network (GCN) and it attempts to measure simultaneous optical light curve associated with GRBs. After 3 years of running, LOTIS has responded to 75 GRB triggers. The lack of any optical signal in any of the LOTIS images places numerical limits on the surrounding matter density, and other physical parameters in the environment of the GRB progenitor. This paper presents LOTIS results and describes other prompt GRB follow-up experiments including the Super-LOTIS at Kitt Peak in Arizona.

  16. Circular polarization in the optical afterglow of GRB 121024A

    CERN Document Server

    Wiersema, K; Toma, K; van der Horst, A J; Varela, K; Min, M; Greiner, J; Starling, R L C; Tanvir, N R; Wijers, R A M J; Campana, S; Curran, P A; Fan, Y; Fynbo, J P U; Gorosabel, J; Gomboc, A; Gotz, D; Hjorth, J; Jin, Z P; Kobayashi, S; Kouveliotou, C; Mundell, C; O'Brien, P T; Pian, E; Rowlinson, A; Russell, D M; Salvaterra, R; Alighieri, S di Serego; Tagliaferri, G; Vergani, S D; Elliott, J; Farina, C; Hartoog, O E; Karjalainen, R; Klose, S; Knust, F; Levan, A J; Schady, P; Sudilovski, V; Willingale, R

    2014-01-01

    Gamma-ray bursts (GRBs) are most probably powered by collimated relativistic outflows (jets) from accreting black holes at cosmological distances. Bright afterglows are produced when the outflow collides with the ambient medium. Afterglow polarization directly probes the magnetic properties of the jet, when measured minutes after the burst, and the geometric properties of the jet and the ambient medium when measured hours to days after the burst. High values of optical polarization detected minutes after burst in GRB 120308A indicate the presence of large-scale ordered magnetic fields originating from the central engine (the power source of the GRB). Theoretical models predict low degrees of linear polarization and negligable circular polarization at late times, when the energy in the original ejecta is quickly transferred to the ambient medium and propagates farther into the medium as a blastwave. Here we report the detection of circularly polarized optical light in the afterglow of GRB 121024A, measured 0.1...

  17. CONSTRAINTS ON VERY HIGH ENERGY EMISSION FROM GRB 130427A

    Energy Technology Data Exchange (ETDEWEB)

    Aliu, E.; Errando, M. [Department of Physics and Astronomy, Barnard College, Columbia University, NY 10027 (United States); Aune, T. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Barnacka, A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Beilicke, M.; Buckley, J. H.; Bugaev, V. [Department of Physics, Washington University, St. Louis, MO 63130 (United States); Benbow, W.; Cerruti, M. [Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645 (United States); Berger, K. [Department of Physics and Astronomy and the Bartol Research Institute, University of Delaware, Newark, DE 19716 (United States); Biteau, J. [Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064 (United States); Byrum, K. [Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States); Cardenzana, J. V; Dickinson, H. J.; Eisch, J. D. [Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Chen, X. [Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam-Golm (Germany); Ciupik, L. [Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605 (United States); Connaughton, V. [Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Cui, W. [Department of Physics and Astronomy, Purdue University, West Lafayette, IN 47907 (United States); Falcone, A., E-mail: aune@astro.ucla.edu, E-mail: sjzhu@umd.edu, E-mail: veres@email.gwu.edu [Department of Astronomy and Astrophysics, 525 Davey Lab, Pennsylvania State University, University Park, PA 16802 (United States); and others

    2014-11-01

    Prompt emission from the very fluent and nearby (z = 0.34) gamma-ray burst GRB 130427A was detected by several orbiting telescopes and by ground-based, wide-field-of-view optical transient monitors. Apart from the intensity and proximity of this GRB, it is exceptional due to the extremely long-lived high-energy (100 MeV to 100 GeV) gamma-ray emission, which was detected by the Large Area Telescope on the Fermi Gamma-Ray Space Telescope for ∼70 ks after the initial burst. The persistent, hard-spectrum, high-energy emission suggests that the highest-energy gamma rays may have been produced via synchrotron self-Compton processes though there is also evidence that the high-energy emission may instead be an extension of the synchrotron spectrum. VERITAS, a ground-based imaging atmospheric Cherenkov telescope array, began follow-up observations of GRB 130427A ∼71 ks (∼20 hr) after the onset of the burst. The GRB was not detected with VERITAS; however, the high elevation of the observations, coupled with the low redshift of the GRB, make VERITAS a very sensitive probe of the emission from GRB 130427A for E > 100 GeV. The non-detection and consequent upper limit derived place constraints on the synchrotron self-Compton model of high-energy gamma-ray emission from this burst.

  18. The Large Aperture GRB Observatory

    CERN Document Server

    Allard, D; Asorey, H; Barros, H; Bertou, X; Castillo, M; Chirinos, J M; De Castro, A; Flores, S; González, J; Berisso, M Gomez; Grajales, J; Guada, C; Day, W R Guevara; Ishitsuka, J; López, J A; Martínez, O; Melfo, A; Meza, E; Loza, P Miranda; Barbosa, E Moreno; Murrugarra, C; Núñez, L A; Ormachea, L J Otiniano; Pérez, G; Perez, Y; Ponce, E; Quispe, J; Quintero, C; Rivera, H; Rosales, M; Rovero, A C; Saavedra, O; Salazar, H; Tello, J C; Peralda, R Ticona; Varela, E; Velarde, A; Villaseñor, L; Wahl, D; Zamalloa, M A

    2009-01-01

    The Large Aperture GRB Observatory (LAGO) is aiming at the detection of the high energy (around 100 GeV) component of Gamma Ray Bursts, using the single particle technique in arrays of Water Cherenkov Detectors (WCD) in high mountain sites (Chacaltaya, Bolivia, 5300 m a.s.l., Pico Espejo, Venezuela, 4750 m a.s.l., Sierra Negra, Mexico, 4650 m a.s.l). WCD at high altitude offer a unique possibility of detecting low gamma fluxes in the 10 GeV - 1 TeV range. The status of the Observatory and data collected from 2007 to date will be presented.

  19. The GRB/XRF-SN Association

    OpenAIRE

    Dar, Arnon

    2004-01-01

    There is mounting evidence that long duration gamma ray bursts (GRBs) and X-ray flashes (XRFs) are produced by highly relativistic and narrowly collimated jets ejected in core collapse supernova (SN) explosions akin to SN 1998bw. We review the history of the GRB-SN association idea and its observational verification. We summarize the present evidence for a GRB/XRF-SN association. We comment on the possibility that most, perhaps all, SN explosions produce GRBs, including SNe of Type Ia which m...

  20. POLAR: a space borne GRB polarimeter

    OpenAIRE

    Lamanna, G; Fouque, N.; Hermel, R.; Vialle, J. P.; Hofer, H; Lechanoine-Leluc, C.; Orsi, S.; Pohl, M.; Rapin, D.; Gierlik, S.M.; Marcinkowski, R.; Courvoisier, T.; Haas, D.; Produit, N.; Hajdas, W.

    2008-01-01

    The direction and the level of polarization of high energy photons emitted by astrophysics sources are valuable observables for the understanding of the corresponding emission mechanisms, source geometry and strength of magnetic fields at work. POLAR is a novel compact space-borne detector conceived for a precise measurement of hard X-ray polarization and optimized for the detection of Gamma-Ray Burst (GRB) photons in the energy range 50-500 keV. In POLAR, the GRB photons undergo Compton scat...

  1. Probing the Cosmic Gamma-Ray Burst Rate with Trigger Simulations of the Swift Burst Alert Telescope

    OpenAIRE

    Lien, Amy; Sakamoto, Takanori; Gehrels, Neil; Palmer, David M.; Barthelmy, Scott D.; Graziani, Carlo; Cannizzo, John K.

    2013-01-01

    The gamma-ray burst (GRB) rate is essential for revealing the connection between GRBs, supernovae and stellar evolution. Additionally, the GRB rate at high redshift provides a strong probe of star formation history in the early universe. While hundreds of GRBs are observed by Swift, it remains difficult to determine the intrinsic GRB rate due to the complex trigger algorithm of Swift. Current studies of the GRB rate usually approximate the Swift trigger algorithm by a single detection thresho...

  2. Confronting GRB prompt emission with a model for subphotospheric dissipation

    CERN Document Server

    Ahlgren, Björn; Nymark, Tanja; Ryde, Felix; Pe'er, Asaf

    2015-01-01

    The origin of the prompt emission in gamma-ray bursts (GRBs) is still an unsolved problem and several different mechanisms have been suggested. Here we fit Fermi GRB data with a photospheric emission model which includes dissipation of the jet kinetic energy below the photosphere. The resulting spectra are dominated by Comptonization and contain no significant contribution from synchrotron radiation. In order to fit to the data we span a physically motivated part of the model's parameter space and create DREAM ($\\textit{Dissipation with Radiative Emission as A table Model}$), a table model for ${\\scriptsize XSPEC}$. We show that this model can describe different kinds of GRB spectra, including GRB 090618, representing a typical Band function spectrum, and GRB 100724B, illustrating a double peaked spectrum, previously fitted with a Band+blackbody model, suggesting they originate from a similar scenario. We suggest that the main difference between these two types of bursts is the optical depth at the dissipatio...

  3. Challenging GRB models through the broadband dataset of GRB060908

    CERN Document Server

    Covino, S; Conciatore, M L; D'Elia, V; Palazzi, E; Thöne, C C; Vergani, S D; Wiersema, K; Brusasca, M; Cucchiara, A; Cobb, B E; Fernandez-Soto, A; Kann, D A; Malesani, D; Tanvir, N R; Antonelli, L A; Bremer, M; Castro-Tirado, A J; Postigo, A de Ugarte; Molinari, E; Nicastro, L; Stefanon, M; Testa, V; Tosti, G; Vitali, F; Amati, L; Chapman, R; Conconi, P; Cutispoto, G; Fynbo, J P U; Goldoni, P; Henriksen, C; Horne, K D; Malaspina, G; Meurs, E J A; Pian, E; Stella, L; Tagliaferri, G; Ward, P; Zerbi, F M

    2010-01-01

    Context: Multiwavelength observations of gamma-ray burst prompt and afterglow emission are a key tool to disentangle the various possible emission processes and scenarios proposed to interpret the complex gamma-ray burst phenomenology. Aims: We collected a large dataset on GRB060908 in order to carry out a comprehensive analysis of the prompt emission as well as the early and late afterglow. Methods: Data from Swift-BAT, -XRT and -UVOT together with data from a number of different ground-based optical/NIR and millimeter telescopes allowed us to follow the afterglow evolution from about a minute from the high-energy event down to the host galaxy limit. We discuss the physical parameters required to model these emissions. Results: The prompt emission of GRB060908 was characterized by two main periods of activity, spaced by a few seconds of low intensity, with a tight correlation between activity and spectral hardness. Observations of the afterglow began less than one minute after the high-energy event, when it ...

  4. GRB afterglow light curves from realistic density profiles

    OpenAIRE

    Mimica, Petar; Giannios, Dimitrios

    2011-01-01

    The afterglow emission that follows gamma-ray bursts (GRBs) contains valuable information about the circumburst medium and, therefore, about the GRB progenitor. Theoretical studies of GRB blast waves, however, are often limited to simple density profiles for the external medium (mostly constant density and power-law R^{-k} ones). We argue that a large fraction of long-duration GRBs should take place in massive stellar clusters where the circumburst medium is much more complicated. As a case s...

  5. Radio Observations of GRB Afterglows

    CERN Document Server

    Weiler, K W; Montes, M J; Weiler, Kurt W.; Panagia, Nino; Montes, Marcos J.

    2002-01-01

    Since 1997 the afterglow of gamma-ray bursting sources (GRBs) has occasionally been detected in the radio, as well in other wavelengths bands. In particular, the interesting and unusual gamma-ray burst GRB980425, thought to be related to the radio supernova SN1998bw, is a possible link between the two classes of objects. Analyzing the extensive radio emission data avaliable for SN1998bw, one can describe its time evolution within the well established framework available for the analysis of radio emission from supernovae. This then allows relatively detailed description of a number of physical properties of the object. The radio emission can best be explained as the interaction of a mildly relativistic shock with a dense preexplosion stellar wind-established circumstellar medium (CSM) that is highly structured both azimuthally, in clumps or filaments, and radially, with observed density enhancements. Because of its unusual characteristics for a Type Ib/c supernova, the relation of SN1998bw to GRB980425 is stre...

  6. A multi band study of the optically dark GRB 051028

    CERN Document Server

    Urata, Yuji; Kuo, Ping-Hung; Ip, Wing-Huen; Qiu, Yulei; Masuno, Keisuke; Tashiro, Makoto; Abe, Keichi; Onda, Kaori; Kodaka, Natsuki; Kuwahara, Makoto; Tamagawa, Toru; Usui, Fumihiko; Ioka, Kunihito; Lee, Yi-Hsi; Wei, Jianyan; Deng, Jinsong; Zheng, Weikang; Makishima, Kazuo

    2007-01-01

    Observations were made of the optical afterglow of GRB 051028 with the Lulin observatory's 1.0 m telescope and the WIDGET robotic telescope system. R band photometric data points were obtained on 2005 October 28 (UT), or 0.095-0.180 days after the burst. There is a possible plateau in the optical light curve around 0.1 days after the burst; the light curve resembles optically bright afterglows (e.g. GRB 041006, GRB 050319, GRB060605) in shape of the light curve but not in brightness. The brightness of the GRB 051028 afterglow is 3 magnitudes fainter than that of one of the dark events, GRB 020124. Optically dark GRBs have been attributed to dust extinction within the host galaxy or high redshift. However, the spectrum analysis of the X-rays implies that there is no significant absorption by the host galaxy. Furthermore, according to the model theoretical calculation of the Ly$\\alpha$ absorption to find the limit of GRB 051028's redshift, the expected $R$ band absorption is not high enough to explain the darkn...

  7. Supernovae and gamma-ray bursts connection

    Energy Technology Data Exchange (ETDEWEB)

    Valle, Massimo Della [INAF-Napoli, Capodimonte Observatory, Salita Moiariello, 16, I-80131 Napoli (Italy); International Center for Relativistic Astrophysics Network, Piazzale della Repubblica 10, I-65122, Pescara (Italy)

    2015-12-17

    I’ll review the status of the Supernova/Gamma-Ray Burst connection. Several pieces of evidence suggest that long duration Gamma-ray Bursts are associated with bright SNe-Ic. However recent works suggest that GRBs might be produced in tight binary systems composed of a massive carbon-oxygen cores and a neutron star companion. Current estimates of the SN and GRB rates yield a ratio GRB/SNe-Ibc in the range ∼ 0.4% − 3%.

  8. Supernovae and gamma-ray bursts connection

    Science.gov (United States)

    Valle, Massimo Della

    2015-12-01

    I'll review the status of the Supernova/Gamma-Ray Burst connection. Several pieces of evidence suggest that long duration Gamma-ray Bursts are associated with bright SNe-Ic. However recent works suggest that GRBs might be produced in tight binary systems composed of a massive carbon-oxygen cores and a neutron star companion. Current estimates of the SN and GRB rates yield a ratio GRB/SNe-Ibc in the range ˜ 0.4% - 3%.

  9. GRB 081007 and GRB 090424: the surrounding medium, outflows and supernovae

    CERN Document Server

    Jin, Zhi-Ping; Della Valle, Massimo; Ferrero, Patrizia; Fugazza, Dino; Malesani, Daniele; Melandri, Andrea; Pian, Elena; Salvaterra, Ruben; Bersier, David; Campana, Sergio; Cano, Zach; D'Avanzo, Paolo; Fynbo, Johan P U; Guidorzi, Cristiano; Haislip, Joshua B; Hjorth, Jens; LaCluyze, Aaron P; Marconi, Gianni; Mazzali, Paolo A; Piranomonte, Silvia; Reichart, Daniel E; Tagliaferri, Gianpiero; Tanvir, Nial R; Valenti, Stefano; Vergani, Susanna D; Vestrand, Thomas; Walker, Emma S; Wozniak, Przemyslaw

    2013-01-01

    We discuss the results of the analysis of multi-wavelength data for the afterglows of GRB 081007 and GRB 090424, two bursts detected by Swift. One of them, GRB 081007, also shows a spectroscopically confirmed supernova, SN 2008hw, which resembles SN 1998bw in its absorption features, while the maximum luminosity is only about half as large as that of SN 1998bw. Bright optical flashes have been detected in both events, which allows us to derive solid constraints on the circumburst-matter density profile. This is particularly interesting in the case of GRB 081007, whose afterglow is found to be propagating into a constant-density medium, yielding yet another example of a GRB clearly associated with a massive star progenitor which did not sculpt the surroundings with its stellar wind. There is no supernova component detected in the afterglow of GRB 090424, likely due to the brightness of the host galaxy, comparable to the Milky Way. We show that the afterglow data are consistent with the presence of both forward...

  10. Probing the Gamma-Ray Burst Rate with Trigger Simulations of the Swift Burst Alert Telescope

    OpenAIRE

    Lien, Amy; Sakamoto, Takanori; Gehrels, Neil; Palmer, David M.; Barthelmy, Scott D.; Graziani, Carlo; Cannizzo, John K.

    2013-01-01

    The long gamma-ray burst (GRB) rate is essential for revealing the connection between GRBs, supernovae and stellar evolution. Additionally, the GRB rate at high redshift provides a strong probe of star formation history in the early universe. While hundreds of GRBs are observed by Swift, it remains difficult to determine the intrinsic GRB rate due to the complex trigger algorithm of Swift. Current studies usually approximate the Swift trigger algorithm by a single detection threshold. However...

  11. A case of mistaken identity? GRB 060912A and the nature of the long -- short GRB divide

    CERN Document Server

    Levan, A J; Chapman, R; Gehrels, N; Gorosabel, J; Hurkett, C; Jakobsson, P; Kouveliotou, C; O'Brien, P T; Osborne, J P; Priddey, R S; Rol, E; Starling, R; Tanvir, N R; Vreeswijk, P M; Wiersema, K

    2007-01-01

    We investigate the origin of the GRB 060912A, which has observational properties that make its classification as either a long or short burst ambiguous. Short duration GRBs (SGRBs) are thought to have typically lower energies than long duration bursts, can be found in galaxies with populations of all ages and are likely to originate from different progenitors to the long duration bursts. However, it has become clear that duration alone is insufficient to make a distinction between the two populations in many cases, leading to a desire to find additional discriminators of burst type. GRB 060912A had a duration of 6 s and occurred only ~10 arcsec from a bright, low redshift ($z=0.0936$) elliptical galaxy, suggesting that this may have been the host, which would favour it being a short-burst. However, our deep optical imaging and spectroscopy of the location of GRB 060912A using the VLT shows that GRB 060912A more likely originates in a distant star forming galaxy at z=0.937, and is most likely a long burst. Thi...

  12. A case of mistaken identity? GRB060912A and the nature of the long-short GRB divide

    Science.gov (United States)

    Levan, A. J.; Jakobsson, P.; Hurkett, C.; Tanvir, N. R.; Gorosabel, J.; Vreeswijk, P.; Rol, E.; Chapman, R.; Gehrels, N.; O'Brien, P. T.; Osborne, J. P.; Priddey, R. S.; Kouveliotou, C.; Starling, R.; vanden Berk, D.; Wiersema, K.

    2007-07-01

    We investigate the origin of the GRB060912A, which has observational properties that make its classification as either a long or short burst ambiguous. Short-duration gamma-ray bursts (SGRBs) are thought to have typically lower energies than long-duration bursts, can be found in galaxies with populations of all ages and are likely to originate from different progenitors to the long-duration bursts. However, it has become clear that duration alone is insufficient to make a distinction between the two populations in many cases, leading to a desire to find additional discriminators of burst type. GRB060912A had a duration of 6s and occurred only ~10arcsec from a bright, low-redshift (z = 0.0936) elliptical galaxy, suggesting that this may have been the host, which would favour it being a short burst. However, our deep optical imaging and spectroscopy of the location of GRB060912A using the Very Large Telescope (VLT) shows that GRB060912A more likely originates in a distant star-forming galaxy at z = 0.937, and is most likely a long burst. This demonstrates the risk in identifying bright, nearby galaxies as the hosts of given gamma-ray bursts (GRBs) without further supporting evidence. Further, it implies that, in the absence of secure identifications, `host' type, or more broadly discriminators that rely on galaxy redshifts, may not be good indicators of the true nature of any given GRB. Based on observations made with ESO telescopes at the Paranal Observatory under programme ID 077.D-0691. E-mail: a.j.levan@warwick.ac.uk

  13. Detailed afterglow modelling and host galaxy properties of the dark GRB 111215A

    DEFF Research Database (Denmark)

    Horst, A. J. van der; Levan, A. J.; Pooley, G. G.;

    2015-01-01

    Gamma-ray burst (GRB) 111215A was bright at X-ray and radio frequencies, but not detected in the optical or near-infrared (nIR) down to deep limits. We have observed the GRB afterglow with the Westerbork Synthesis Radio Telescope and Arcminute Microkelvin Imager at radio frequencies, with the Wil...

  14. A multi-colour study of the dark GRB 000210 host galaxy and its environment

    DEFF Research Database (Denmark)

    Gorosabel, J.; Christensen, Lise; Hjorth, J.;

    2003-01-01

    We present UBVRIZJsHKs broad band photometry of the host galaxy of the dark gamma-ray burst (GRB) of February 10, 2000. These observations represent the most exhaustive photometry given to date of any GRB host galaxy. A grid of spectral templates have been fitted to the Spectral Energy Distribution...

  15. The Early Optical Brightening in the GRB 071010B

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J H; Schwamb, M E; Huang, K Y; Wen, C Y; Zhang, Z W; Wang, S Y; Chen, W P; Bianco, F B; Dave, R; Lehner, M J; Marshall, S L; Porrata, R; Alcock, C; Byun, Y I; Cook, K H; King, S K; Lee, T; Urata, Y

    2008-04-08

    We report the detection of early (60-230 s) optical emission of the gamma-ray burst afterglow of GRB071010B. No significant correlation with the prompt {gamma}-ray emission was found. Our high time-resolution data combining with other measurements within 2 days after the burst indicate that GRB071010B is composed of a weak early brightening ({alpha} {approx} 0.6), probably caused by the peak frequency passing through the optical wavelengths, followed by a decay ({alpha} {approx} -0.51), attributed to continuous energy injection by patchy jets.

  16. How long does a burst burst?

    International Nuclear Information System (INIS)

    Several gamma-ray bursts (GRBs) last much longer (∼hours) in γ-rays than typical long GRBs (∼minutes), and it has recently been proposed that these 'ultra-long GRBs' may form a distinct population, probably with a different (e.g., blue supergiant) progenitor than typical GRBs. However, Swift observations suggest that many GRBs have extended central engine activities manifested as flares and internal plateaus in X-rays. We perform a comprehensive study on a large sample of Swift GRBs with X-Ray Telescope observations to investigate GRB central engine activity duration and to determine whether ultra-long GRBs are unusual events. We define burst duration t burst based on both γ-ray and X-ray light curves rather than using γ-ray observations alone. We find that t burst can be reliably measured in 343 GRBs. Within this 'good' sample, 21.9% GRBs have t burst ≳ 103 s and 11.5% GRBs have t burst ≳ 104 s. There is an apparent bimodal distribution of t burst in this sample. However, when we consider an 'undetermined' sample (304 GRBs) with t burst possibly falling in the gap between GRB duration T 90 and the first X-ray observational time, as well as a selection effect against t burst falling into the first Swift orbital 'dead zone' due to observation constraints, the intrinsic underlying t burst distribution is consistent with being a single component distribution. We found that the existing evidence for a separate ultra-long GRB population is inconclusive, and further multi-wavelength observations are needed to draw a firmer conclusion. We also discuss the theoretical implications of our results. In particular, the central engine activity duration of GRBs is generally much longer than the γ-ray T 90 duration and it does not even correlate with T 90. It would be premature to make a direct connection between T 90 and the size of the progenitor star.

  17. Testing GRB models with the strange afterglow of GRB 090102

    CERN Document Server

    Gendre, B; Palazzi, E; Kruhler, T; Covino, S; Afonso, P; Antonelli, L A; Atteia, J L; D'Avanzo, P; Boër, M; Greiner, J; Klose, S

    2009-01-01

    We present the observations of the afterglow of gamma-ray burst GRB 090102. We use optical data taken by the TAROT, REM, GROND, Palomar and NOT telescopes, and X-ray data taken by the XRT instrument on board the Swift spacecraft. This event features an unusual light curve. In X-rays, it presents a very monotonic decrease with no hint of temporal break from 0.005 to 6 days after the burst. In optical, the light curve presents a flattening after 1 ks. Before this break, the optical light curve is steeper than the X-ray one. In optical, no further break is observed up to 10 days after the burst. We tried to explain these observations in light of the standard fireball model, but we failed to do so. We then investigated several other models, like the cannonball model. We find that the explanation of the broad band data by any model requires a strong fine tuning when taking into account both optical and X-ray bands.

  18. Detectability of GRB optical afterglows with Gaia satellite

    CERN Document Server

    Japelj, J

    2011-01-01

    With the launch of Gaia satellite, detection of many different types of transient sources will be possible, one of them being optical afterglows of gamma-ray bursts (GRBs). Using the knowledge of the satellites dynamics and properties of GRB optical afterglows we performed a simulation in order to estimate an average GRB detection rate with Gaia. Here we present the simulation results for two types of GRB optical afterglows, differing in the observer's line-of-sight compared to a GRB jet axis: regular (on-axis) and orphan afterglows. Results show that for on-axis GRBs, less than 10 detections in five years of foreseen Gaia operational time are expected. The orphan afterglows simulation results are more promising, giving a more optimistic number of several tens of detections in five years.

  19. The GRB-SN connection: GRB030329 and XRF030723

    OpenAIRE

    Fynbo, J. P. U.; Hjorth, J.; Sollerman, J.; Moller, P.; Gorosabel, J.; S. Guziy; Woosley, S.; Kouveliotou, C.; Grundahl, F.; Jensen, B. L.; Andersen, M. I.; Vreeswijk, P.; Castro-Tirado, A. J.; collaboration, the GRACE

    2004-01-01

    The attempt to secure conclusive, spectroscopic evidence for the GRB/SN connection has been a central theme in most GRB observing time proposals since the discovery of the very unusual GRB980425 associated with the peculiar type Ib/c SN1998bw. GRB030329 provided this evidence to everybody's satisfaction. In this contribution we show the results of a spectroscopic campaign of the supernova associated with GRB030329 carried out at ESOs Very Large Telescope. We also present preliminary results f...

  20. Spectral lag features of GRB 060814 from swift bat and Suzaku observations

    International Nuclear Information System (INIS)

    This work reports a study on the spectral lag of the prompt emission spectrum of a multi-pulse gamma-ray burst (GRB) GRB 060814 (z = 0.84) using the observations of the Swift Burst Alert Telescope and the Suzaku Wide Area Monitor. We found that the spectral lag for GRB 060814 is positive for the first two and the fourth pulses, while the third pulse exhibits negative lag. However, the time variation of the E peak of all the stated pulses shows a similar trend. The leading models for spectral lags in GRBs are thus found inadequate to explain the observed spectral lag features of GRB 060814. Probable causes of the spectral lag characteristics of GRB 060814 are discussed.

  1. The Possible Impact of GRB Detector Thresholds on Cosmological Standard Candles

    OpenAIRE

    Shahmoradi, A.; Nemiroff, R. J.

    2009-01-01

    GRB satellites are relatively inefficient detectors of dim hard bursts because they trigger on photon counts, which are number-biased against hard photons. Therefore, for example, given two bursts of identical peak luminosity near the detection threshold, a dim soft burst will be preferentially detected over a dim hard burst. This detector bias can create or skew an apparent correlation where increasingly hard GRBs appear increasingly bright. Although such correlations may be obfuscated by a ...

  2. GRB070610 : A Curious Galactic Transient

    CERN Document Server

    Kasliwal, M M; Kulkarni, S R; Cameron, P B; Nakar, E; Ofek, E O; Rau, A; Soderberg, A M; Campana, S; Bloom, J S; Perley, D A; Pollack, L; Barthelmy, S; Cummings, J; Gehrels, N; Krimm, H A; Markwardt, C B; Sato, G; Chandra, P; Frail, D; Fox, D B; Price, P; Berger, E; Grebenev, S A; Krivonos, R A; Sunyaev, R A

    2007-01-01

    GRB070610 is a typical high-energy event with a duration of 5s. Yet within the burst localization we detect a highly unusual X-ray and optical transient, Swift J195509.6+261406. We see high amplitude X-ray and optical variability on very short time scales even at late times. Using near-infrared imaging assisted by a laser guide star and adaptive optics, we have identified a quiescent counterpart to Swift J195509.6+261406. Our spectroscopic observations show that the spectral type of the counterpart is likely a K dwarf/sub-giant. It is possible that GRB070610 and Swift J195509.6+261406 are unrelated sources. However, the absence of a typical X-ray afterglow from GRB070610 in conjunction with the spatial and temporal coincidence of GRB070610 and Swift J195509.6+261406 motivate us to suggest that the sources are related. The closest analog to Swift J195509.6+261406 is V4641 Sgr, an unusual black hole binary. We suggest that Swift J195509.6+261406 along with V4641 Sgr define a sub-class of stellar black holes -- ...

  3. The Swift GRB Host Galaxy Legacy Survey

    Science.gov (United States)

    Perley, Daniel

    2015-08-01

    I will describe the Swift Host Galaxy Legacy Survey (SHOALS), a comprehensive multiwavelength program to characterize the demographics of the GRB host population and its redshift evolution from z=0 to z=7. Using unbiased selection criteria we have designated a subset of 119 Swift gamma-ray bursts which are now being targeted with intensive observational follow-up. Deep Spitzer imaging of every field has already been obtained and analyzed, with major programs ongoing at Keck, GTC, Gemini, VLT, and Magellan to obtain complementary optical/NIR photometry and spectroscopy to enable full SED modeling and derivation of fundamental physical parameters such as mass, extinction, and star-formation rate. Using these data I will present an unbiased measurement of the GRB host-galaxy luminosity and mass distributions and their evolution with redshift, compare GRB hosts to other star-forming galaxy populations, and discuss implications for the nature of the GRB progenitor and the ability of GRBs to serve as tools for measuring and studying cosmic star-formation in the distant universe.

  4. GRB 011121 A Massive Star Progenitor

    CERN Document Server

    Price, P A; Reichart, D E; Kulkarni, S R; Subramanian, R; Wark, R M; Wieringa, M H; Frail, D A; Bailey, J; Boyle, B; Corbett, E A; Gunn, K; Ryder, S D; Seymour, N; Koviak, K; McCarthy, P; Phillips, M; Axelrod, T S; Bloom, J S; Djorgovski, S G; Fox, D W; Galama, T J; Harrison, F A; Hurley, K; Sari, R; Schmidt, B P; Yost, S A; Brown, M J I; Cline, T; Frontera, F; Guidorzi, C; Montanari, E

    2002-01-01

    Of the cosmological gamma-ray bursts, GRB 011121 has the lowest redshift, z=0.36. More importantly, the multi-color excess in the afterglow detected in the Hubble Space Telescope (HST) light curves is compelling observational evidence for an underlying supernova. Here we present near-infrared and radio observations of the afterglow. We undertake a comprehensive modeling of these observations and those reported in the literature and find good evidence favoring a wind-fed circumburst medium. In detail, we infer the progenitor had a mass loss rate of Mdot ~ 10^-7 / v_w3 Mo/yr where v_w3 is the speed of the wind from the progenitor in units of 10^3 km/s. This mass loss rate is similar to that inferred for the progenitor of SN 1998bw which has been associated with GRB 980425. Our data, taken in conjunction with the HST results of Bloom et al. (2002), provide a consistent picture: the long duration GRB 011121 had a massive star progenitor which exploded as a supernova at about the same time as the GRB event.

  5. BeppoSAX attitude operations for GRB follow up

    International Nuclear Information System (INIS)

    This poster describes the attitude dynamics software, Attitude and Orbit Control Ground Support System (AOCGSS), which was developed by TELESPAZIO and integrated in the Operations Control Centre (OCC), in order to support the on ground operations of the Attitude and Orbit Control Subsystem (AOCS). In particular its involvement during the operations performed to carry out the Gamma Ray Burst (GRB) Follow Up is described

  6. Spectroscopy of the short-hard GRB 130603B

    DEFF Research Database (Denmark)

    Postigo, A. de Ugarte; Thoene, C. C.; Rowlinson, A.;

    2014-01-01

    Short duration gamma-ray bursts (SGRBs) are thought to be related to the violent merger of compact objects, such as neutron stars or black holes, which makes them promising sources of gravitational waves. The detection of a 'kilonova'-like signature associated to the Swift-detected GRB 130603B ha...

  7. An External Shock Origin of GRB $\\textit{141028A}$

    CERN Document Server

    Burgess, J Michael; Ryde, Felix; Omodei, Nicola; Pe'er, Asaf; Racusin, J L; Cucchiara, A

    2015-01-01

    The prompt emission of the long, smooth, and single-pulsed gamma-ray burst, GRB $\\textit{141028A}$, is analyzed under the guise of an external shock model. First, we fit the $\\gamma$-ray spectrum with a two-component photon model, namely synchrotron+blackbody, and then fit the recovered evolution of the synchrotron $\

  8. How Long does a Burst Burst?

    CERN Document Server

    Zhang, Bin-Bin; Murase, Kohta; Connaughton, Valerie; Briggs, Michael S

    2013-01-01

    Several gamma-ray bursts (GRBs) last much longer (~ hours) in gamma-rays than typical long GRBs (~ minutes), and recently it was proposed that these "ultra-long GRBs" may form a distinct population, probably with a different (e.g. blue supergiant) progenitor than typical GRBs. However, Swift observations have suggested that many GRBs have extended central engine activities manifested as flares and internal plateaus in X-rays. We perform a comprehensive study on a large sample of Swift GRBs with XRT observations to investigate GRB central engine activity duration and to check whether ultra-long GRBs are special. We define burst duration t_{burst} based on both gamma-ray and X-ray light curves rather than using gamma-ray observations only. We show that the distribution of t_{burst} peaks at ~ 320s for the entire sample, with 17.6% GRBs having t_{burst} > 10^3 s and 5.4% GRBs having t_{burst} > 10^4 s. The distribution shows a tail at the long t_{burst} end. The existence of a separate population is not ruled ou...

  9. Probing the Cosmic Gamma-Ray Burst Rate with Trigger Simulations of the Swift Burst Alert Telescope

    CERN Document Server

    Lien, Amy; Gehrels, Neil; Palmer, David M; Barthelmy, Scott D; Graziani, Carlo; Cannizzo, John K

    2013-01-01

    The gamma-ray burst (GRB) rate is essential for revealing the connection between GRBs, supernovae and stellar evolution. Additionally, the GRB rate at high redshift provides a strong probe of star formation history in the early universe. While hundreds of GRBs are observed by Swift, it remains difficult to determine the intrinsic GRB rate due to the complex trigger algorithm of Swift. Current studies of the GRB rate usually approximate the Swift trigger algorithm by a single detection threshold. However, unlike the previously flown GRB instruments, Swift has over 500 trigger criteria based on photon count rate and additional image threshold for localization. To investigate possible systematic biases and explore the intrinsic GRB properties, we develop a program that is capable of simulating all the rate trigger criteria and mimicking the image threshold. Our simulations show that adopting the complex trigger algorithm of Swift increases the detection rate of dim bursts. As a result, our simulations suggest bu...

  10. Probing the Gamma-Ray Burst Rate with Trigger Simulations of the Swift Burst Alert Telescope

    CERN Document Server

    Lien, Amy; Gehrels, Neil; Palmer, David M; Barthelmy, Scott D; Graziani, Carlo; Cannizzo, John K

    2013-01-01

    The long gamma-ray burst (GRB) rate is essential for revealing the connection between GRBs, supernovae and stellar evolution. Additionally, the GRB rate at high redshift provides a strong probe of star formation history in the early universe. While hundreds of GRBs are observed by Swift, it remains difficult to determine the intrinsic GRB rate due to the complex trigger algorithm of Swift. Current studies usually approximate the Swift trigger algorithm by a single detection threshold. However, unlike the previously flown GRB instruments, Swift has over 500 trigger criteria based on photon count rate and additional image threshold for localization. To investigate possible systematic biases and explore the intrinsic GRB properties, we developed a program that is capable of simulating all the rate trigger criteria and mimicking the image trigger threshold. We use this program to search for the intrinsic GRB rate. Our simulations show that adopting the complex trigger algorithm of Swift increases the detection ra...

  11. $\\gamma$-ray Burst Positions from the ASM on RXTE

    CERN Document Server

    Bradt, H V; Bradt, Hale V.; Smith, Donald A.

    1999-01-01

    The RXTE/ASM has detected and positioned 14 confirmed GRB bursts (at this writing, Jan. 1999) including six whose positions were comunicated to the community 2 to 32 hours after the burst. Two of these latter bursts led to measurements of optical red shifts but one, despite an easily detected x-ray afterglow, produced no detectable optical or radio afterglow.

  12. The red optical afterglow of GRB 030725

    CERN Document Server

    Pugliese, G; Gorosabel, J; Jensen, B L; Fynbo, J P U; Hjorth, J; Jorgensen, S F; Monard, B; Vinter, C

    2005-01-01

    We present a photometric study of the optical counterpart of the long-duration Gamma Ray Burst (GRB) 030725, which triggered the HETE FREGATE and WXM instruments on July 25th, 2003, and lasted more than 160s. An optical counterpart was identified at the Bronberg Observatory in South Africa about 7 hours after the burst occurred. The optical afterglow (OA) was observed between 4 and 15 days after the burst with the 1.54m Danish telescope at La Silla in the V, Rc, and Ic bands. We fit a broken power law to the data and determine a break time in the light curve between 16 hours and 4.7 days after the first detection of the burst. The decay slope is alpha1 = -0.59 +0.59/-0.44 before and alpha2 = -1.43 +/- 0.06 after the break. A bump may be present in the light curve, only significant at the 2-sigma level, 13.9 days after the main burst. The spectral slope of the OA, measured 12 days after the burst, is -2.9 +/- 0.6 , i.e. it falls in the extreme red end of the distribution of previous OA spectral slopes. Observa...

  13. UVES/VLT high resolution spectroscopy of GRB 050730 afterglow: probing the features of the GRB environment

    Energy Technology Data Exchange (ETDEWEB)

    D' Elia, V.; Fiore, F.; Piranomonte, S.; Sbordone, L.; Stella, L.; Antonelli, L.A.; Fontana, A.; Giannini, T.; Guetta, D.; Israel, G.; Testa, V. [INAF, Osservatorio Astron Roma, I-00044 Frascati, (Italy); Meurs, E.J.A.; Vergani, S.D.; Ward, P. [Dunsink Observ, Dublin 15, (Ireland); Chincarini, G.; Tagliaferri, G.; Campana, S.; Fugazza, D.; Molinari, E.; Moretti, A. [INAF, Osservatorio Astron Brera, I-23807 Merate, LC, (Italy); Chincarini, G. [Univ Milano Bicocca, I-20126 Milan, (Italy); Melandri, A. [Liverpool John Moores Univ, Astron Res Inst, Birkenhead, Merseyside, (United Kingdom); Norci, L.; Vergani, S.D. [Dublin City Univ, Sch Phys Sci, Dublin 9, (Ireland); Pellizza, L.; Filliatre, P. [Dublin City Univ, NCPST, Dublin 9, (Ireland); Perna, R.; Lazzati, D. [CEA Saclay, DSM, DAPNIA, Serv Astrophys, F-91191 Gif Sur Yvette, (France)] (and others)

    2007-07-01

    Aims. The aim of this paper is to study the Gamma Ray Burst (GRB) environment through the analysis of the optical absorption features due to the gas surrounding the GRB. Methods. To this purpose we analyze high resolution spectroscopic observations (R = 20000-45000, corresponding to 14 kms{sup -1} at 4200 Angstroms and 6.6 kms{sup -1} at 9000 Angstroms of the optical afterglow of GRB050730, obtained with UVES-VLT {approx} 4 h after the GRB trigger. Results. The spectrum shows that the ISM of the GRB host galaxy at z = 3.967 is complex, with at least five components contributing to the main absorption system. We detect strong CII*, SiII*, OI* and FeII* fine structure absorption lines associated to the second and third component. Conclusions. For the first three components we derive information on the relative distance from the site of the GRB explosion. Component 1, which has the longest wavelength, highest positive velocity shift, does not present any fine structure nor low ionization lines; it only shows very high ionization features, such as C IV and O VI, suggesting that this component is very close to the GRB site. From the analysis of low and high ionization lines and fine structure lines, we find evidences that the distance of component 2 from the site of the GRB explosion is 10-100 times smaller than that of component 3. We evaluated the mean metallicity of the z = 3.967 system obtaining values approximate to 10{sup -2} of the solar metallicity or less. However, this should not be taken as representative of the circum-burst medium, since the main contribution to the hydrogen column density comes from the outer regions of the galaxy while that of the other elements presumably comes from the ISM closer to the GRB site. Furthermore, difficulties in evaluating dust depletion correction can modify significantly these values. The mean [C/Fe] ratio agrees well with that expected by single star-formation event models. Interestingly the [C/Fe] of component 2 is

  14. Ultra-Fast Flash Observatory: Fast Response Space Missions for Early Time Phase of Gamma Ray Bursts

    DEFF Research Database (Denmark)

    Park, I.H.; Ahmad, S.; Barrillon, P.;

    2013-01-01

    -second response, for the first time, opening a completely new frontier in GRB and transient studies. Its fast response measurements of the optical emission of dozens of GRB each year will provide unique probes of the burst mechanism and test the prospect of GRB as a new standard candle, potentially opening up the...

  15. Very high column density and small reddening toward GRB 020124 at z=3.20

    DEFF Research Database (Denmark)

    Hjorth, J.; Møller, Per; Gorosabel, J.;

    2003-01-01

    We present optical and near-infrared observations of the dim afterglow of GRB 020124, obtained between 2 and 68 hr after the gamma-ray burst. The burst occurred in a very faint (Rgreater than or similar to29.5) damped Lyalpha absorber (DLA) at a redshift of z=3.198+/-0.004. The derived column...

  16. Circular polarization in the optical afterglow of GRB 121024A.

    Science.gov (United States)

    Wiersema, K; Covino, S; Toma, K; van der Horst, A J; Varela, K; Min, M; Greiner, J; Starling, R L C; Tanvir, N R; Wijers, R A M J; Campana, S; Curran, P A; Fan, Y; Fynbo, J P U; Gorosabel, J; Gomboc, A; Götz, D; Hjorth, J; Jin, Z P; Kobayashi, S; Kouveliotou, C; Mundell, C; O'Brien, P T; Pian, E; Rowlinson, A; Russell, D M; Salvaterra, R; di Serego Alighieri, S; Tagliaferri, G; Vergani, S D; Elliott, J; Fariña, C; Hartoog, O E; Karjalainen, R; Klose, S; Knust, F; Levan, A J; Schady, P; Sudilovsky, V; Willingale, R

    2014-05-01

    Gamma-ray bursts (GRBs) are most probably powered by collimated relativistic outflows (jets) from accreting black holes at cosmological distances. Bright afterglows are produced when the outflow collides with the ambient medium. Afterglow polarization directly probes the magnetic properties of the jet when measured minutes after the burst, and it probes the geometric properties of the jet and the ambient medium when measured hours to days after the burst. High values of optical polarization detected minutes after the burst of GRB 120308A indicate the presence of large-scale ordered magnetic fields originating from the central engine (the power source of the GRB). Theoretical models predict low degrees of linear polarization and no circular polarization at late times, when the energy in the original ejecta is quickly transferred to the ambient medium and propagates farther into the medium as a blast wave. Here we report the detection of circularly polarized light in the afterglow of GRB 121024A, measured 0.15 days after the burst. We show that the circular polarization is intrinsic to the afterglow and unlikely to be produced by dust scattering or plasma propagation effects. A possible explanation is to invoke anisotropic (rather than the commonly assumed isotropic) electron pitch-angle distributions, and we suggest that new models are required to produce the complex microphysics of realistic shocks in relativistic jets. PMID:24776800

  17. Circular polarization in the optical afterglow of GRB 121024A

    Science.gov (United States)

    Wiersema, K.; Covino, S.; Toma, K.; van der Horst, A. J.; Varela, K.; Min, M.; Greiner, J.; Starling, R. L. C.; Tanvir, N. R.; Wijers, R. A. M. J.; Campana, S.; Curran, P. A.; Fan, Y.; Fynbo, J. P. U.; Gorosabel, J.; Gomboc, A.; Götz, D.; Hjorth, J.; Jin, Z. P.; Kobayashi, S.; Kouveliotou, C.; Mundell, C.; O'Brien, P. T.; Pian, E.; Rowlinson, A.; Russell, D. M.; Salvaterra, R.; di Serego Alighieri, S.; Tagliaferri, G.; Vergani, S. D.; Elliott, J.; Fariña, C.; Hartoog, O. E.; Karjalainen, R.; Klose, S.; Knust, F.; Levan, A. J.; Schady, P.; Sudilovsky, V.; Willingale, R.

    2014-05-01

    Gamma-ray bursts (GRBs) are most probably powered by collimated relativistic outflows (jets) from accreting black holes at cosmological distances. Bright afterglows are produced when the outflow collides with the ambient medium. Afterglow polarization directly probes the magnetic properties of the jet when measured minutes after the burst, and it probes the geometric properties of the jet and the ambient medium when measured hours to days after the burst. High values of optical polarization detected minutes after the burst of GRB 120308A indicate the presence of large-scale ordered magnetic fields originating from the central engine (the power source of the GRB). Theoretical models predict low degrees of linear polarization and no circular polarization at late times, when the energy in the original ejecta is quickly transferred to the ambient medium and propagates farther into the medium as a blast wave. Here we report the detection of circularly polarized light in the afterglow of GRB 121024A, measured 0.15 days after the burst. We show that the circular polarization is intrinsic to the afterglow and unlikely to be produced by dust scattering or plasma propagation effects. A possible explanation is to invoke anisotropic (rather than the commonly assumed isotropic) electron pitch-angle distributions, and we suggest that new models are required to produce the complex microphysics of realistic shocks in relativistic jets.

  18. LATE-TIME OBSERVATIONS OF GRB 080319B: JET BREAK, HOST GALAXY, AND ACCOMPANYING SUPERNOVA

    International Nuclear Information System (INIS)

    The Swift-discovered GRB 080319B was by far the most distant source ever observed at naked-eye brightness, reaching a peak apparent magnitude of 5.3 at a redshift of z = 0.937. We present our late-time optical (Hubble Space Telescope, Gemini, and Very Large Telescope) and X-ray (Chandra) observations, which confirm that an achromatic break occurred in the power-law afterglow light curve at ∼11 days post-burst. This most likely indicates that the gamma-ray burst (GRB) outflow was collimated, which for a uniform jet would imply a total energy in the jet Ejet ∼> 1052 erg. Our observations also show a late-time excess of red light, which is well explained if the GRB was accompanied by a supernova (SN), similar to those seen in some other long-duration GRBs. The latest observations are dominated by light from the host and show that the GRB took place in a faint dwarf galaxy (r(AB) ∼ 27.0, rest frame MB ∼ -17.2). This galaxy is small even by the standards of other GRB hosts, which is suggestive of a low-metallicity environment. Intriguingly, the properties of this extreme event-a small host and bright SN-are entirely typical of the very low luminosity bursts such as GRB 980425 and GRB 060218.

  19. GRB environment properties through X and optical afterglow observations

    International Nuclear Information System (INIS)

    We present the spectral analysis of 14 gamma-ray bursts (GRB) X-ray afterglows in order to investigate the properties of interstellar matter (ISM) along the line of sight of GRB. We carried out a simultaneous analysis of the NIR-optical and X-band for those afterglows with an optical counterpart too, in order to evaluate and strongly constrain the absorption effect on the spectral energy distribution due to dust extinction from GRB environment. We evaluated the equivalent hydrogen column density NH from X-ray spectroscopy and rest frame visual extinction Aν by assuming different type of ISM composition and dust grain size distribution. From our analysis we obtained a distribution of the GRB rest frame consistent with the one expected if GRB were embedded in a galactic-like molecular cloud. Moreover, values of the visual extinction estimated from the simultaneous analysis or NIR-to-X band favour an environment where small dust grains are destroyed by the interaction with the X-ray and UV photons from GRB

  20. GRB environment properties through X and optical afterglow observations

    CERN Document Server

    Conciatore, M L; Stratta, G; Fiore, F; Perna, R

    2005-01-01

    We present the spectral analysis of 14 gamma-ray bursts (GRB) X-ray afterglows in order to investigate the properties of interstellar matter (ISM) along the line of sight of GRB. We carried out a simultaneous analysis of the NIR-optical and X-band for those afterglows with an optical counterpart too, in order to evaluate and strongly constrain the absorption effect on the spectral energy distribution due to dust extinction from GRB environment. We evaluated the equivalent hydrogen column density Nh from X-ray spectroscopy and rest frame visual extinction Av by assuming different type of ISM composition and dust grain size distribution. From our analysis we obtained a distribution of the GRB rest frame consistent with the one expected if GRB were embedded in a Galactic-like molecular cloud. Moreover, values of the visual extinction estimated from the simultaneous analysis of NIR-to-X band favour an environment where small dust grain are destroyed by the interaction with the X-ray and UV photons from GRB.

  1. GRB 050904: the oldest cosmic explosion ever observed in the Universe

    International Nuclear Information System (INIS)

    Swift discovered the high redshift (z=6.29) GRB 050904 with the Burst Alert Telescope and began observing with its narrow field instruments only 161 s after the burst onset. GRB 050904 was a long, multi-peaked, bright GRB with a presence of flaring activity lasting up to 1-2 hours after the burst onset. The spectral energy distribution shows a clear softening trend along the burst evolution with a photon index decreasing from -1.2 up to -1.9. The observed variability is more dramatic than the typical Swift afterglow, the amplitude and rise/fall times of the flares are consistent with the behavior of nearby (z ≤ 1) long GRBs and suggest the interpretation of the BAT and XRT data as a single continuous observation of long lasting prompt emission

  2. Constraints on Very High Energy Emission from GRB 130427A

    CERN Document Server

    Aliu, E; Barnacka, A; Beilicke, M; Benbow, W; Berger, K; Biteau, J; Buckley, J H; Bugaev, V; Byrum, K; Cardenzana, J V; Cerruti, M; Chen, X; Ciupik, L; Connaughton, V; Cui, W; Dickinson, H J; Eisch, J D; Errando, M; Falcone, A; Federici, S; Feng, Q; Finley, J P; Fleischhack, H; Fortin, P; Fortson, L; Furniss, A; Galante, N; Gillanders, G H; Griffin, S; Griffiths, S T; Grube, J; Gyuk, G; Håkansson, N; Hanna, D; Holder, J; Hughes, G; Humensky, T B; Johnson, C A; Kaaret, P; Kar, P; Kertzman, M; Khassen, Y; Kieda, D; Krawczynski, H; Krennrich, F; Lang, M J; Madhavan, A S; Maier, G; McArthur, S; McCann, A; Meagher, K; Millis, J; Moriarty, P; Mukherjee, R; Nieto, D; de Bhróithe, A O'Faoláin; Ong, R A; Otte, A N; Park, N; Pohl, M; Popkow, A; Prokoph, H; Pueschel, E; Quinn, J; Ragan, K; Rajotte, J; Reyes, L C; Reynolds, P T; Richards, G T; Roache, E; Sembroski, G H; Shahinyan, K; Smith, A W; Staszak, D; Telezhinsky, I; Tucci, J V; Tyler, J; Varlotta, A; Vassiliev, V V; Vincent, S; Wakely, S P; Weiner, O M; Weinstein, A; Welsing, R; Wilhelm, A; Williams, D A; Zitzer, B; McEnery, J E; Perkins, J S; Veres, P; Zhu, S

    2014-01-01

    Prompt emission from the very fluent and nearby (z=0.34) gamma-ray burst GRB 130427A was detected by several orbiting telescopes and by ground-based, wide-field-of-view optical transient monitors. Apart from the intensity and proximity of this GRB, it is exceptional due to the extremely long-lived high-energy (100 MeV to 100 GeV) gamma-ray emission, which was detected by the Large Area Telescope on the Fermi Gamma-ray Space Telescope for ~70 ks after the initial burst. The persistent, hard-spectrum, high-energy emission suggests that the highest-energy gamma rays may have been produced via synchrotron self-Compton processes though there is also evidence that the high-energy emission may instead be an extension of the synchrotron spectrum. VERITAS, a ground-based imaging atmospheric Cherenkov telescope array, began follow-up observations of GRB 130427A ~71 ks (~20 hr) after the onset of the burst. The GRB was not detected with VERITAS; however, the high elevation of the observations, coupled with the low redsh...

  3. Extremely hard GRB spectra prune down the forest of emission models

    CERN Document Server

    Ghirlanda, G; Ghisellini, G; Ghirlanda, Giancarlo; Celotti, Annalisa; Ghisellini, Gabriele

    2003-01-01

    We consider the evidence for very hard low energy spectra during the prompt phase of Gamma Ray Bursts (GRB). In particular we examine the spectral evolution of GRB 980306 together with the detailed analysis of some other bursts already presented in the literature (GRB 911118, GRB 910807, GRB 910927 and GRB 970111), and check for the significance of their hardness by applying different tests. These are among the bursts with the hardest low energy spectrum, sufficiently bright to allow time resolved spectral studies on time intervals of the order of tenths of a second. We discuss the hard spectra of these bursts and their evolution in the context of several non--thermal emission models, which all appear inadequate to account for these cases. The extremely hard spectra at the beginning of their prompt emission are also compared with a black body spectral model: the resulting fits are remarkably good, except for an excess at high energies (in several cases) which could be simply accounted for by the presence of a...

  4. Polarization Evolution of the GRB 020405 Afterglow

    OpenAIRE

    S. Covino(INAF - Oss. Astronomico di Brera); Malesani, D.; Ghisellini, G.; Lazzati, D.; Alighieri, S. di Serego; Stefanon, M.; Cimatti, A.; Della Valle, M.; Fiore, F.; Goldoni, P.; Kawai, N.; Israel, G. L.; Floc'h, E. Le; Mirabel, I. F.; Ricker, G.

    2002-01-01

    Polarization measurements for the optical counterpart to GRB 020405 are presented and discussed. Our observations were performed with the VLT-UT3 (Melipal) during the second and third night after the gamma-ray burst discovery. The polarization degree (and the position angle) appears to be constant between our two observations at a level around (1.5 - 2)%. The polarization can be intrinsic but it is not possible to unambiguously exclude that a substantial fraction of it is induced by dust in t...

  5. GRB Cosmology and Self-organized Criticality in GRBs

    OpenAIRE

    Wang, F.Y.

    2015-01-01

    Gamma-ray bursts (GRBs), which have isotropic energy up to $10^{54}$ erg, would be the ideal tool to study the properties of early universe: including dark energy, star formation rate, and the metal enrichment history of the Universe. We will briefly review the progress on the field of GRB cosmology. Meanwhile, X-ray flares, which may have important clues to the central engine, are common phenomena in the GRB afterglows. We present statistical results of X-ray flares, i.e., energy, duration t...

  6. Dynamics and stability of relativistic GRB blast waves

    OpenAIRE

    Meliani, Z.; Keppens, R.

    2010-01-01

    In gamma-ray-bursts (GRB), ultra-relativistic blast waves are ejected into the circumburst medium. We analyse in unprecedented detail the deceleration of a self-similar Blandford-McKee blast wave from a Lorentz factor 25 to the nonrelativistic Sedov phase. Our goal is to determine the stability properties of its frontal shock. We carried out a grid-adaptive relativistic 2D hydro-simulation at extreme resolving power, following the GRB jet during the entire afterglow phase. We investigate the ...

  7. A GRB Follow-up System at the Xinglong Observatory and Detection of the High-Redshift GRB 060927

    CERN Document Server

    Zheng, W; Zhai, M; Xin, L; Qiu, Y; Wang, J; Lü, X; Wei, J; Hu, J; 10.1088/1009-9271/8/6/08

    2009-01-01

    A gamma-ray burst (GRB) optical photometric follow-up system at the Xinglong Observatory of National Astronomical Observatories of China (NAOC) has been constructed. It uses the 0.8-m Tsinghua-NAOC Telescope (TNT) and the 1-m EST telescope, and can automatically respond to GRB Coordinates Network (GCN)alerts. Both telescopes slew relatively fast, being able to point to a new target field within about 1 min upon a request. Whenever available, the 2.16-m NAOC telescope is also used. In 2006, the system responded to 15 GRBs and detected seven early afterglows. In 2007, six GRBs have been detected among 18 follow-up observations. TNT observations of the second most distant GRB 060927 (z=5.5) are shown, which started as early as 91s after the GRB trigger. The afterglow was detected in the combined image of first 19x20s unfiltered exposures. This GRB follow-up system has joined the East-Asia GRB Follow-up Observation Network (EAFON).

  8. GRB 110721A: photosphere "death line" and the physical origin of the GRB "Band" function

    CERN Document Server

    Zhang, Bing; Liang, En-Wei; Wu, Xue-Feng

    2012-01-01

    The prompt emission spectra of gamma-ray bursts (GRBs) usually have a dominant component that is well described by a phenomenological "Band" function. The physical origin of this spectral component is debated. Although the traditional interpretation is synchrotron radiation of non-thermal electrons accelerated in internal shocks or magnetic dissipation regions, a growing trend in the community is to interpret this component as emission from the dissipative photosphere of a GRB fireball. We analyze the time dependent spectrum of GRB 110721A detected by Fermi GBM and LAT, and pay special attention to the rapid evolution of the peak energy $E_p$. We define a "death line" of baryonic photospheric emission in the $E_p - L$ plane, and show that $E_p$ of GRB 110721A at the earliest epoch has a very high $E_p \\sim 15$ MeV that is beyond the "death line". This rules out the baryonic photosphere model for the "Band" component for this burst. Together with the finding that an additional "shoulder" component exists in th...

  9. FERMI OBSERVATIONS OF HIGH-ENERGY GAMMA-RAY EMISSION FROM GRB 080825C

    International Nuclear Information System (INIS)

    The Fermi Gamma-ray Space Telescope has opened a new high-energy window in the study of gamma-ray bursts (GRBs). Here we present a thorough analysis of GRB 080825C, which triggered the Fermi Gamma-ray Burst Monitor (GBM), and was the first firm detection of a GRB by the Fermi Large Area Telescope (LAT). We discuss the LAT event selections, background estimation, significance calculations, and localization for Fermi GRBs in general and GRB 080825C in particular. We show the results of temporal and time-resolved spectral analysis of the GBM and LAT data. We also present some theoretical interpretation of GRB 080825C observations as well as some common features observed in other LAT GRBs.

  10. Spectroscopic Discovery of the Supernova Associated with GRB 030329

    CERN Document Server

    Stanek, K Z; Garnavich, P M; Martini, P; Caldwell, P B N; Challis, P M; Brown, W; Schild, R; Krisciunas, K; Calkins, M L; Lee, J C; Hathi, N; Jansen, R; Windhorst, R A; Echevarria, L; Eisenstein, D J; Pindor, B; Olszewski, E W; Harding, P; Bersier, D F

    2003-01-01

    We present early observations of the afterglow of the Gamma-Ray Burst (GRB) 030329 and the spectroscopic discovery of its associated supernova. We obtained spectra of the afterglow of GRB 030329 each night from March 30.12 (0.6 days after the burst) to April 8.13 (UT) (9.6 days after the burst). The spectra cover a wavelength range of 350 nm to 850 nm. The early spectra consist of a power-law continuum (F_{nu} ~ nu^{-0.9}) with narrow emission lines originating from HII regions in the host galaxy, indicating a low redshift of z=0.1687. However, our spectra taken after 2003 Apr. 5 show broad peaks in flux characteristic of a supernova. Correcting for the afterglow emission, we find the spectrum of the supernova is remarkably similar to the type Ic `hypernova' SN 1998bw. While the presence of supernovae have been inferred from the light curves and colors of GRB afterglows in the past, this is the first direct, spectral confirmation that a subset of classical gamma-ray bursts originate from supernovae.

  11. Search for strong gravitational lensing effect in the current GRB data of BATSE

    CERN Document Server

    Li, Chun-Yu

    2014-01-01

    Because gamma-ray bursts (GRBs) trace the high-z Universe, there is an appreciable probability for a GRB to be gravitational lensed by galaxies in the universe. Herein we consider the gravitational lensing effect of GRBs contributed by the dark matter halos in galaxies. Assuming that all halos have the singular isothermal sphere (SIS) mass profile in the mass range $10^{10} h^{-1} M_\\odot < M < 2\\times 10^{13} h^{-1}M_\\odot $ and all GRB samples follow the intrinsic redshift distribution and luminosity function derived from the Swift LGRBs sample, we calculated the gravitational lensing probability in BATSE, Swift/BAT and Fermi/GBM GRBs, respectively. With an derived probability result in BATSE GRBs, we searched for lensed GRB pairs in the BATSE 5B GRB Spectral catalog. The search did not find any convincing gravitationally lensed events. We discuss our result and future observations for GRB lensing observation.

  12. Neutrino emission from a GRB afterglow shock during an inner supernova shock breakout

    CERN Document Server

    Yu, Yun-Wei; Zheng, Xiao-Ping

    2008-01-01

    The observations of a nearby low-luminosity gamma-ray burst (GRB) 060218 associated with supernova SN 2006aj may imply an interesting astronomical picture where a supernova shock breakout locates behind a relativistic GRB jet. Based on this picture, we study neutrino emission for early afterglows of GRB 060218-like GRBs, where neutrinos are expected to be produced from photopion interactions in a GRB blast wave that propagates into a dense wind. Relativistic protons for the interactions are accelerated by an external shock, while target photons are basically provided by the incoming thermal emission from the shock breakout and its inverse-Compton scattered component. Because of a high estimated event rate of low-luminosity GRBs, we would have more opportunities to detect afterglow neutrinos from a single nearby GRB event of this type by IceCube. Such a possible detection could provide evidence for the picture described above.

  13. GRB Cosmology and Self-organized Criticality in GRBs

    CERN Document Server

    Wang, F Y

    2015-01-01

    Gamma-ray bursts (GRBs), which have isotropic energy up to $10^{54}$ erg, would be the ideal tool to study the properties of early universe: including dark energy, star formation rate, and the metal enrichment history of the Universe. We will briefly review the progress on the field of GRB cosmology. Meanwhile, X-ray flares, which may have important clues to the central engine, are common phenomena in the GRB afterglows. We present statistical results of X-ray flares, i.e., energy, duration time and waiting time distributions, and compare the results with solar flares. The similarity between the two kinds of flares are found, which may indicates that the physical mechanism of GRB X-ray flares is magnetic reconnection.

  14. High Precision Analyses of Lyman alpha Damping Wing of Gamma-Ray Bursts in the Reionization Era: On the Controversial Results from GRB 130606A at z = 5.91

    CERN Document Server

    Totani, Tomonori; Hattori, Takashi; Kawai, Nobuyuki

    2015-01-01

    The unprecedentedly bright afterglow of GRB 130606A at z = 5.91 gave us a unique opportunity to probe the reionization era by high precision analyses of the redward damping wing of Lyman alpha absorption, but the reported constraints on the neutral hydrogen fraction (f_{HI}) in intergalactic medium (IGM) derived from spectra taken by different telescopes are in contradiction. Here we examine the origin of this discrepancy by analyzing the spectrum taken by VLT with our own analysis code previously used to fit the Subaru spectrum. Though the VLT team reported no evidence for IGM HI using the VLT spectrum, we confirmed our previous result of 3-4 sigma preference for non-zero IGM HI (f_{HI} ~ 0.06, when IGM HI extends to the GRB redshift). The fit residuals of the VLT spectrum by the model without IGM HI show the same systematic trend as the Subaru spectrum. We consider that the likely origin of the discrepancy between the two teams is the difference of the wavelength ranges adopted in the fittings; our waveleng...

  15. The origin and location of the 5 March 1979 gamma-ray burst

    Science.gov (United States)

    Kazanas, Demosthenes

    1988-01-01

    Evidence and arguments concerning the origin and location of the gamma-ray burst (GRB) of March 5, 1979 are reviewed. This GRB has been positionally identified with the SNR 49 in the LMC. Such an association would fix the GRB's distance at 55 kpc, and the observed flux from the GRB would require prodigious energy and luminosity, casting doubt on the GRB's distance and its association with the LMC. Some Kosmos 856 observations which may provide more direct evidence on the energy released are discussed.

  16. Effect of GRB spectra on the empirical luminosity correlations and the GRB Hubble diagram

    Science.gov (United States)

    Lin, Hai-Nan; Li, Xin; Chang, Zhe

    2016-04-01

    The spectra of gamma-ray bursts (GRBs) in a wide energy range can usually be well described by the Band function, which is a two smoothly jointed power laws cutting at a breaking energy. Below the breaking energy, the Band function reduces to a cut-off power law, while above the breaking energy it is a simple power law. However, for some detectors (such as the Swift-BAT) whose working energy is well below or just near the breaking energy, the observed spectra can be fitted to cut-off power law with enough precision. Besides, since the energy band of Swift-BAT is very narrow, the spectra of most GRBs can be fitted well even using a simple power law. In this paper, with the most up-to-date sample of Swift-BAT GRBs, we study the effect of different spectral models on the empirical luminosity correlations, and further investigate the effect on the reconstruction of GRB Hubble diagram. We mainly focus on two luminosity correlations, i.e., the Amati relation and Yonetoku relation. We calculate these two luminosity correlations on both the case that the GRB spectra are modeled by Band function and cut-off power law. It is found that both luminosity correlations only moderately depend on the choice of GRB spectra. Monte Carlo simulations show that Amati relation is insensitive to the high-energy power-law index of the Band function. As a result, the GRB Hubble diagram calibrated using luminosity correlations is almost independent on the GRB spectra.

  17. A trio of gamma-ray burst supernovae

    DEFF Research Database (Denmark)

    Cano, Z.; Ugarte Postigo, Antonio de; Pozanenko, A.;

    2014-01-01

    We present optical and near-infrared (NIR) photometry for three gamma-ray burst supernovae (GRB-SNe): GRB 120729A, GRB 130215A / SN 2013ez and GRB 130831A / SN 2013fu. In the case of GRB 130215A / SN 2013ez, we also present optical spectroscopy at t-t0=16.1 d, which covers rest-frame 3000......-6250 Angstroms. Based on Fe II (5169) and Si (II) (6355), our spectrum indicates an unusually low expansion velocity of 4000-6350 km/s, the lowest ever measured for a GRB-SN. Additionally, we determined the brightness and shape of each accompanying SN relative to a template supernova (SN 1998bw), which were used...

  18. A method for searching the Whipple Observatory gamma ray data base for evidence of GRB's

    International Nuclear Information System (INIS)

    In light of recent Gamma Ray Burst (GRB) data from GRO, it is desirable to have a method for searching data from the Fred Lawrence Whipple Observatory 10 meter Cherenkov telescope for evidence of GRB's at TeV energies. In particular, this instrument's narrow field of view and high angular resolution make it well suited for observations of M31 as a test of the galactic halo model of GRB origin. We present here such a method, and give the results of its application to data taken on M31. Also reported here is an upper limit for the detection of a DC signal from M31

  19. GRB Follow-up Observations with the Whipple Telescope and VERITAS

    International Nuclear Information System (INIS)

    GRB observations above 100 GeV promise to constrain source models decisively and may also permit to study questions in other fields such as quantum gravity. The VERITAS collaboration has been working on GRB follow-up observations for several years using the Whipple 10 m telescope on Mt. Hopkins, AZ. We present a preliminary summary of the bursts for which interesting data is available. Even though the telescope mount was not optimized for this task, GRB follow-ups within less than 5 minutes have been possible. The new telescopes of the VERITAS array (under construction) will bring a further reduction in reaction time and an improvement in sensitivity

  20. A SUPRAMASSIVE MAGNETAR CENTRAL ENGINE FOR GRB 130603B

    International Nuclear Information System (INIS)

    We show that the peculiar early optical emission and, in particular, the X-ray afterglow emission of the short-duration burst GRB 130603B can be explained by continuous energy injection into the blastwave from a supramassive magnetar central engine. The observed energetics and temporal/spectral properties of the late infrared bump (i.e., the kilonova) are also found to be consistent with emission from the ejecta launched during a neutron star (NS)-NS merger and powered by a magnetar central engine. The isotropic-equivalent kinetic energies of both the gamma-ray burst (GRB) blastwave and the kilonova are approximately Ek ∼ 1051 erg, consistent with being powered by a near-isotropic magnetar wind. However, this relatively small value requires that most of the initial rotational energy of the magnetar (∼a few × 1052 erg) is carried away by gravitational wave radiation. Our results suggest that (1) the progenitor of GRB 130603B was a NS-NS binary system, the merger product of which would have been a supramassive NS that lasted for about ∼1000 s; (2) the equation of state of the nuclear matter should be stiff enough to allow the survival of a long-lived supramassive NS; thus this suggested that the detection of the bright electromagnetic counterparts of gravitational wave triggers without short GRB associations is promising in the upcoming Advanced LIGO/VIRGO era

  1. WIDGET: System Performance and GRB Prompt Optical Observations

    CERN Document Server

    Urata, Yuji; Tamagawa, Toru; Usui, Fumihiko; Kuwahara, Makoto; Lin, Hungmiao; Kageyama, Shoichi; Iwakiri, Wataru; Sugasahara, Takako; Takahara, Kazuki; Kodaka, Natsuki; Abe, Keiichi; Masuno, Keisuke; Onda, Kaori

    2010-01-01

    The WIDeField telescope for Gamma-ray burst Early Timing (WIDGET) is used for a fully automated, ultra-wide-field survey aimed at detecting the prompt optical emission associated with Gamma-ray Bursts (GRBs). WIDGET surveys the HETE-2 and Swift/BAT pointing directions covering a total field of view of 62 degree x 62 degree every 10 secounds using an unfiltered system. This monitoring survey allows exploration of the optical emission before the gamma-ray trigger. The unfiltered magnitude is well converted to the SDSS r' system at a 0.1 mag level. Since 2004, WIDGET has made a total of ten simultaneous and one pre-trigger GRB observations. The efficiency of synchronized observation with HETE-2 is four times better than that of Swift. There has been no bright optical emission similar to that from GRB 080319B. The statistical analysis implies that GRB080319B is a rare event. This paper summarizes the design and operation of the WIDGET system and the simultaneous GRB observations obtained with this instrument.

  2. SRG/eROSITA prospects for detection of GRB afterglows

    CERN Document Server

    Khabibullin, I I; Sunyaev, R A

    2012-01-01

    We discuss the potential of the eROSITA telescope on board the \\emph{Spectrum-X-Gamma} observatory to detect gamma-ray burst (GRB) X-ray afterglows during its 4-year all-sky survey. The expected rate of afterglows associated with long-duration GRBs without any information on the bursts proper that can be identified by a characteristic power-law light curve in the eROSITA data is 4--8 events per year. An additional small number, $\\lesssim 2$ per year, of afterglows may be associated with short GRBs, ultra hard (GeV) GRBs and X-ray flashes. eROSITA can thus provide the first unbiased (unaffected by GRB triggering) sample of $\\lesssim 40$ X-ray afterglows, which can be used for statistical studies of GRB afterglows and for constraining the shape of the GRB $\\log N$--$\\log S$ distribution at its low-fluence end. The total number of afterglows detected by eROSITA may be yet higher due to orphan afterglows and failed GRBs. The actual detection rate could thus provide interesting constraints on the properties of rel...

  3. Fast radio burst/gamma-ray burst cosmography

    International Nuclear Information System (INIS)

    Recently, both theoretical arguments and observational evidence suggested that a small fraction of fast radio bursts (FRBs) could be associated with gamma-ray bursts (GRBs). If such FRB/GRB association systems are commonly detected in the future, the combination of dispersion measures (DM) derived from FRBs and redshifts derived from GRBs makes these systems a plausible tool to conduct cosmography. We quantify uncertainties in deriving the redshift-dependent DMIGM as a function of z and test how well dark energy models can be constrained with Monte Carlo simulations. We show that with several tens of FRB/GRB systems potentially detected in a decade or so, one may reach reasonable constraints on wCDM models. When combined with Type Ia supernova (SN Ia) data, unprecedented constraints on the dark energy equation of state may be achieved, thanks to the prospects of detecting FRB/GRB systems at relatively high redshifts. The ratio between the mean value and luminosity distance (D L(z)) is insensitive to dark energy models. This gives the prospect of applying SN Ia data to calibrate using a relatively small sample of FRB/GRB systems, allowing a reliable constraint on the baryon inhomogeneity distribution as a function of redshift. The methodology developed in this paper can also be applied if the FRB redshifts can be measured by other means. Some caveats of putting this method into practice are also discussed.

  4. Radio rebrightening of the GRB afterglow by the accompanying supernova

    CERN Document Server

    Duran, Rodolfo Barniol

    2015-01-01

    The gamma-ray burst (GRB) jet powers the afterglow emission by shocking the surrounding medium, and radio afterglow can now be routinely observed to almost a year after the explosion. Long-duration GRBs are accompanied by supernovae (SNe) that typically contain much more energy than the GRB jet. Here we consider the fact that the SN blast wave will also produce its own afterglow, which will peak at much later time (since it is non-relativistic), when the SN blast wave transitions from a coasting phase to a decelerating Sedov-Taylor phase. We predict that this component will peak generally a few tens of years after the explosion and it will outshine the GRB powered afterglow well-before its peak emission. In the case of GRB 030329, where the external density is constrained by the $\\sim 10$-year coverage of the radio GRB afterglow, the radio emission is predicted to start rising over the next decade and to continue to increase for the following decades up to a level of $\\sim 0.5$ mJy. Detection of the SN-powere...

  5. Radio rebrightening of the GRB afterglow by the accompanying supernova

    Science.gov (United States)

    Barniol Duran, R.; Giannios, D.

    2015-12-01

    The gamma-ray burst (GRB) jet powers the afterglow emission by shocking the surrounding medium, and radio afterglow can now be routinely observed to almost a year after the explosion. Long-duration GRBs are accompanied by supernovae (SNe) that typically contain much more energy than the GRB jet. Here we consider the fact that the SN blast wave will also produce its own afterglow (supernova remnant emission), which will peak at much later time (since it is non-relativistic), when the SN blast wave transitions from a coasting phase to a decelerating Sedov-Taylor phase. We predict that this component will peak generally a few tens of years after the explosion and it will outshine the GRB powered afterglow well-before its peak emission. In the case of GRB 030329, where the external density is constrained by the ˜10-year coverage of the radio GRB afterglow, the radio emission is predicted to start rising over the next decade and to continue to increase for the following decades up to a level of ˜ mJy. Detection of the SN-powered radio emission will greatly advance our knowledge of particle acceleration in ˜0.1c shocks.

  6. Fermi Large Area Telescope observations of GRB 110625A

    CERN Document Server

    Tam, P H Thomas; Fan, Yi-Zhong

    2012-01-01

    Gamma-ray bursts (GRBs) that emit photons at GeV energies form a small but significant population of GRBs. However, the number of GRBs whose GeV-emitting period is simultaneously observed in X-rays remains small. We report gamma-ray observations of GRB 110625A using Fermi's Large Area Telescope (LAT) in the energy range 100 MeV to 20 GeV. Gamma-ray emission at these energies was clearly detected using data taken between 180s and 580s after the burst, an epoch after the prompt emission phase. The GeV light curve differs from a simple power-law decay, and probably consists of two emission periods. Simultaneous Swift/XRT observations did not show flaring behaviors as in the case of GRB 100728A. We discuss the possibility that the GeV emission is the synchrotron self-Compton radiation of underlying ultraviolet flares.

  7. Strategies for Prompt Searches for GRB Afterglows: The Discovery of GRB 001011 Optical/Near-Infrared Counterpart Using Colour-Colour Selection

    Science.gov (United States)

    Gorosabel, J.; Fynbo, J. U.; Hjorth, J.; Wolf, C.; Andersen, M. I.; Pedersen, H.; Christensen, L.; Jensen, B. L.; Moller, P.; Afonso, J.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    We report the discovery of the optical and near-infrared counterpart to GRB 001011. The GRB 001011 error box determined by Beppo-SAX was simultaneously imaged in the near-infrared by the 3.58-m. New Technology Telescope and in the optical by the 1.54-m Danish Telescope - 8 hr after the gamma-ray event. We implement the colour-colour discrimination technique proposed by Rhoads (2001) and extend it using near-IR data as well. We present the results provided by an automatic colour-colour discrimination pipe-line developed to discern the different populations of objects present in the GRB 001011 error box. Our software revealed three candidates based on single-epoch images. Second-epoch observations carried out approx. 3.2 days after the burst revealed that the most likely candidate had faded thus identifying it with the counterpart to the GRB. In deep R-band images obtained 7 months after the burst a faint (R=25.38 plus or minus 0.25) elongated object, presumably the host galaxy of GRB 001011, was detected at the position of the afterglow. The GRB 001011 afterglow is the first discovered with the assistance of colour-colour diagram techniques. We discuss the advantages of using this method and its application to boxes determined by future missions.

  8. The distribution of equivalent widths in long GRB afterglow spectra

    Science.gov (United States)

    de Ugarte Postigo, A.; Fynbo, J. P. U.; Thöne, C. C.; Christensen, L.; Gorosabel, J.; Milvang-Jensen, B.; Schulze, S.; Jakobsson, P.; Wiersema, K.; Sánchez-Ramírez, R.; Leloudas, G.; Zafar, T.; Malesani, D.; Hjorth, J.

    2012-12-01

    Context. The extreme brightness of gamma-ray burst (GRB) afterglows and their simple spectral shape make them ideal beacons to study the interstellar medium of their host galaxies through absorption line spectroscopy at almost any redshift. Aims: We describe the distribution of rest-frame equivalent widths (EWs) of the most prominent absorption features in GRB afterglow spectra, providing the means to compare individual spectra to the sample and identify its peculiarities. Methods: Using 69 low-resolution GRB afterglow spectra, we conduct a study of the rest-frame EWs distribution of features with an average rest-frame EW larger than 0.5 Å. To compare an individual GRB with the sample, we develop EW diagrams as a graphical tool, and we give a catalogue with diagrams for the 69 spectra. We introduce a line strength parameter (LSP) that allows us to quantify the strength of the absorption features in a GRB spectrum as compared to the sample by a single number. Using the distributions of EWs of single-species features, we derive the distribution of their column densities by a curve of growth (CoG) fit. Results: We find correlations between the LSP and the extinction of the GRB, the UV brightness of the host galaxies and the neutral hydrogen column density. However, we see no significant evolution of the LSP with the redshift. There is a weak correlation between the ionisation of the absorbers and the energy of the GRB, indicating that, either the GRB event is responsible for part of the ionisation, or that galaxies with high-ionisation media produce more energetic GRBs. Spectral features in GRB spectra are, on average, 2.5 times stronger than those seen in QSO intervening damped Lyman-α (DLA) systems and slightly more ionised. In particular we find a larger excess in the EW of C ivλλ1549 relative to QSO DLAs, which could be related to an excess of Wolf-Rayet stars in the environments of GRBs. From the CoG fitting we obtain an average number of components in the

  9. H.E.S.S. Observations of the Prompt and Afterglow Phases of GRB 060602B

    CERN Document Server

    Aharonian, F; Barresde Almeida, U; Bazer-Bachi, A R; Behera, B; Beilicke, M; Benbow, W; Bernlöhr, K; Boisson, C; Borrel, V; Braun, I; Brion, E; Brucker, J; Buhler, R; Bulik, T; Büsching, I; Boutelier, T; Carrigan, S; Chadwick, P M; Chaves, R; Chounet, L M; Clapson, A C; Coignet, G; Cornils, R; Costamante, L; Dalton, M; Degrange, B; Dickinson, H J; Djannati-Atai, A; Domainko, W; O'Connor-Drury, L; Dubois, F; Dubus, G; Dyks, J; Egberts, K; Emmanoulopoulos, D; Espigat, P; Farnier, C; Feinstein, F; Fiasson, A; Förster, A; Fontaine, G; Fussling, M; Gabici, S; Gallant, Y A; Giebels, B; Glicenstein, J F; Glück, B; Goret, P; Hadjichristidis, C; Hauser, D; Hauser, M; Heinzelmann, G; Henri, G; Hermann, G; Hinton, J A; Hoffmann, A; Hofmann, W; Holleran, M; Hoppe, S; Horns, D; Jacholkowska, A; De Jager, O C; Jung, I; Katarzy, K; Kendziorra, E; Kerschhaggl, M; Khangulyan, D; Kh, B; Keogh, D; Komin, Nu; Kosack, K; Lamanna, G; Latham, I J; Lenain, J P; Lohse, T; Martin, J M; Martineau-Huynh, O; Marcowith, A; Masterson, C; Maurin, D; McComb, T J L; Moderski, R; Moulin, E; Naumann-Godo, M; De Naurois, Mathieu; Nedbal, D; Nekrassov, D; Nolan, S J; Ohm, S; Olive, J P; De Ona Wilhelmi, E; Orford, K J; Osborne, J L; Ostrowski, M; Panter, M; Pedaletti, G; Pelletier, G; Petrucci, P O; Pita, S; Pühlhofer, G; Punch, M; Quirrenbach, Andreas G; Raubenheimer, B C; Raue, M; Rayner, S M; Renaud, M; Rieger, F; Ripken, J; Rob, L; Rosier-Lees, S; Rowell, G; Rudak, B; Ruppel, J; Sahakian, V V; Santangelo, A; Schlickeiser, R; Sch, F M; Schroder, R; Schwanke, U; Schwarzburg, S; Schwemmer, S; Shalchi, A; Sol, H; Spangler, D; Stawarz, L; Steenkamp, R; Stegmann, C; Superina, G; Tam, P H; Tavernet, J P; Terrier, R; Van Eldik, C; Vasileiadis, G; Venter, C; Vialle, J P; Vincent, P; Vivier, M; Völk, H J; Volpe, F; Wagner, S J; Ward, M; Zdziarski, A A; Zech, A

    2008-01-01

    We report on the first completely simultaneous observation of a gamma-ray burst (GRB) using an array of Imaging Atmospheric Cherenkov Telescopes which is sensitive to photons in the very-high-energy (VHE) gamma-ray range (>~100 GeV). On 2006 June 2, the Swift Burst Alert Telescope (BAT) registered an unusually soft gamma-ray burst (GRB 060602B). The burst position was under observation using the High Energy Stereoscopic System (H.E.S.S.) at the time the burst occurred. Data were taken before, during, and after the burst. A total of 5 hours of observations were obtained during the night of 2006 June 2-3, and 5 additional hours were obtained over the next 3 nights. No VHE gamma-ray signal was found during the period covered by the H.E.S.S. observations. The 99% confidence level flux upper limit (>1 TeV) for the prompt phase (9s) of GRB 060602B is 2.9x10^-9 erg cm^-2 s^-1. Due to the very soft BAT spectrum of the burst compared to other Swift GRBs and its proximity to the Galactic center, the burst is likely ass...

  10. X-ray Emission Lines in GRB Afterglows: Evidence for a Two-component Jet Model

    Institute of Scientific and Technical Information of China (English)

    Wei-Hong Gao; Da-Ming Wei

    2005-01-01

    X-ray emission lines have been observed in X-ray afterglows of several γ-ray bursts (GRBs). It is a major breakthrough for understanding the nature of the progenitors. It has been proposed that the X-ray emission lines can be well explained by the Geometry-Dominated models, but in these models the illuminating angle is much larger than that of the collimated jet of the GRB. For GRB 011211, we have obtained an illuminating angle of about θ~ 45°, while the angle of the GRB jet is only 3.6°. So we propose that the outflow of GRBs with emission lines should have two distinct components: a wide component that illuminates the reprocessing material and produces the emission lines and a narrow one that produces the GRB. Observations show the energy for producing the emission lines is higher than that of the GRB. In this case, when the wide component dominates the afterglows, a bump should appear in the GRB afterglow. For GRB 011211,the bump should occur within 0.05 days of the GRB, which is obviously too early for the observation to catch it. Alongside the X-ray emission lines there should also be a bright emission component between the UV and the soft X-rays. These features can be tested by the Swift satellite in the near future.

  11. Gamma Ray Bursts

    Science.gov (United States)

    Gehrels, Neil; Meszaros, Peter

    2012-01-01

    Gamma-ray bursts (GRBs) are bright flashes of gamma-rays coming from the cosmos. They occur roughly once per day ,last typically lOs of seconds and are the most luminous events in the universe. More than three decades after their discovery, and after pioneering advances from space and ground experiments, they still remain mysterious. The launch of the Swift and Fermi satellites in 2004 and 2008 brought in a trove of qualitatively new data. In this review we survey the interplay between these recent observations and the theoretical models of the prompt GRB emission and the subsequent afterglows.

  12. Gamma-Ray Bursts

    Science.gov (United States)

    Gehrels, Neil; Mészáros, Péter

    2012-08-01

    Gamma-ray bursts (GRBs) are bright flashes of gamma rays coming from the cosmos. They occur roughly once per day, typically last for tens of seconds, and are the most luminous events in the universe. More than three decades after their discovery, and after pioneering advances from space and ground experiments, they still remain mysterious. The launch of the Swift and Fermi satellites in 2004 and 2008 brought in a trove of qualitatively new data. In this Review, we survey the interplay between these recent observations and the theoretical models of the prompt GRB emission and the subsequent afterglow.

  13. Gamma Ray Bursts

    CERN Document Server

    Gehrels, Neil; 10.1126/science.1216793

    2012-01-01

    Gamma-ray bursts (GRBs) are bright flashes of gamma-rays coming from the cosmos. They occur roughly once per day, last typically 10s of seconds and are the most luminous events in the universe. More than three decades after their discovery, and after pioneering advances from space and ground experiments, they still remain mysterious. The launch of the Swift and Fermi satellites in 2004 and 2008 brought in a trove of qualitatively new data. In this review we survey the interplay between these recent observations and the theoretical models of the prompt GRB emission and the subsequent afterglows.

  14. Testing and Performance of UFFO Burst Alert & Trigger Telescope

    DEFF Research Database (Denmark)

    Rípa, Jakub; Bin Kim, Min; Lee, Jik;

    2014-01-01

    The Ultra-Fast Flash Observatory pathfinder (UFFO-p) is a new space mission dedicated to detect Gamma-Ray Bursts (GRBs) and rapidly follow their afterglows in order to provide early optical/ultraviolet measurements. A GRB location is determined in a few seconds by the UFFO Burst Alert & Trigger...

  15. The detailed optical light curve of GRB 030329

    CERN Document Server

    Lipkin, Yu M; Gal-Yam, A; Leibowitz, E M; Poznanski, D; Kaspi, S; Polishook, D; Kulkarni, S R; Fox, D W; Berger, E; Mirabal, N; Halpern, J; Bureau, M; Fathi, K; Price, P A; Peterson, B A; Frebel, A; Schmidt, B; Orosz, J A; Fitzgerald, J B; Bloom, J S; Van Dokkum, P G; Bailyn, C D; Buxton, M M; Barsony, M

    2004-01-01

    (Abridged) We present densely sampled BVRI light curves of the optical transient associated with the gamma-ray burst GRB 030329, the result of a coordinated observing campaign conducted at five observatories. Augmented with published observations of this GRB, the compiled optical dataset contains 2687 photometric measurements, obtained between 78 minutes and 79 days after the burst. We show that the underlying supernova 2003dh evolved faster than, and was probably somewhat fainter than the type Ic SN 1998bw, associated with GRB 980425. We find that our data can be described by a broken power-law decay perturbed by a complex variable component. The early- and late-time decay slopes are determined to be ~1.1 and ~2, respectively. Assuming this single power-law model, we constrain the break to lie between ~3 and ~8 days after the burst. This simple, singly-broken power-law model, derived only from the analysis of our optical observations, may also account for available multi-band data, provided that the break ha...

  16. The prompt GRB high energy emission from internal shocks: synchrotron vs inverse Compton component

    International Nuclear Information System (INIS)

    We performed a detailed calculation of gamma-ray burst (GRB) prompt emission in the framework of the internal shock scenario, focusing on the high energy (GeV) bands. In order to follow the evolution of the ultrarelativistic inhomogeneous wind, we combined a model for the dynamics of internal shocks with a detailed calculation of the radiative processes occurring in the shocked medium. We present the resulting synthetic GRB light curves and spectra. We show the spectral evolution that can be expected for different sets of microphysics parameters and parameters of the dynamical evolution, and how the relative importance of synchrotron and inverse Compton components is varying during a burst.

  17. Swift XRT Observations of X-ray Flares in GRB Afterglows

    OpenAIRE

    Burrows, David N.; Romano, P; Godet, O.; Falcone, A; Pagani, C.; Cusumano, G.; Campana, S.; Chincarini, G.; Hill, J E; Giommi, P.; Goad, M. R.; Kennea, J. A.; Kobayashi, S; Meszaros, P.; Nousek, J. A.

    2005-01-01

    The Swift XRT has been observing GRB afterglows since December 23, 2004. Three-quarters of these observations begin within 300 s of the burst onset, providing an unprecendented look at the behavior of X-ray emission from GRB afterglows in the first few hours after the burst. While most of the early afterglows have smoothly declining lightcurves, a substantial fraction has large X-ray flares on short time-scales. We suggest that these flares provide support for models with extended central eng...

  18. Gamma-ray bursts prospects and conflicts. To the experiments the last word

    International Nuclear Information System (INIS)

    Gamma-ray bursts (GRB) are one of the most interesting astrophysical phenomenon ever observed. Since their discovery, the nature of GRB has been one of the great puzzles of modern astrophysics. During the last decade, two major experimental results provided new insight in our understanding of GRB. First, BATSE discovered that GRB are distributed isotropically over the sky giving a first indication of their cosmological origin. The second result has been obtained by BeppoSAX that discovered GRB afterglows. This confirmed the fireball model and led to observations in other wavelengths. The emerging picture is that GRB involve relativistic motion and are related to supernova explosions and the formation of a black hole. With the most recent observations the common understanding is that at least the long bursts originate in explosions of very massive stars or near the regions of massive star formation

  19. Variable polarization in the optical afterglow of GRB 021004

    CERN Document Server

    Rol, E; Fynbo, J P U; Hjorth, J; Gorosabel, J; Egholm, M P; Castro-Cerón, J M; Castro-Tirado, A J; Kaper, L; Masetti, N; Palazzi, E; Pian, E; Tanvir, N R; Vreeswijk, P M; Kouveliotou, C; Møller, P; Pedersen, H; Fruchter, A S; Rhoads, J; Burud, I; Salamanca, I; Van den Heuvel, E P J

    2003-01-01

    We present polarimetric observations of the afterglow of gamma-ray burst (GRB) 021004, obtained with the Nordic Optical Telescope (NOT) and the Very Large Telescope (VLT) between 8 and 17 hours after the burst. Comparison among the observations shows a 45 degree change in the position angle from 9 hours after the burst to 16 hours after the burst, and comparison with published data from later epochs even shows a 90 degree change between 9 and 89 hours after the burst. The degree of linear polarization shows a marginal change, but is also consistent with being constant in time. In the context of currently available models for changes in the polarization of GRBs, a homogeneous jet with an early break time of t_b ~ 1 day provides a good explanation of our data. The break time is a factor 2 to 6 earlier than has been found from the analysis of the optical light curve. The change in the position angle of the polarization rules out a structured jet model for the GRB.

  20. GRB 060206: Evidence of Precession of Central Engine

    International Nuclear Information System (INIS)

    The high-redshift (z = 4.048) gamma-ray burst GRB 060206 showed unusual behavior, with a significant re-brightening about 3000 s after the burst. We assume that the central engine became active again 2000 s after the main burst and drove another more collimated off-axis jet. The two jets both interacted with the ambient medium and contributed to the whole emission. We numerically fit this optical afterglow from the two jets using the forward-shock model and the forward-reverse shock model. Combining with the zero time effect, we suggest that the fast rise at ∼3000 s in the afterglow was due to the off-axis emission from the second jet. The precession of the torus or accretion disk of the gamma ray burst engine is the natural explanation for the symmetry axes of these two jets not to lie on the same line

  1. Evidence for TeV Emission from GRB 970417a

    CERN Document Server

    Atkins, R; Berley, D; Chen, M L; Coyne, D G; Dingus, B L; Dorfan, D E; Ellsworth, R W; Evans, D; Falcone, A D; Fleysher, L; Fleysher, R; Gisler, G; Goodman, J A; Haines, T J; Hoffman, C M; Hugenberger, S; Kelley, L A; Leonor, I; McConnell, M; McCullough, J F; McEnery, J E; Miller, R S; Mincer, A I; Morales, M F; Némethy, P; Ryan, J M; Shen, B; Shoup, A L; Sinnis, C; Smith, A J; Sullivan, G W; Tümer, T O; Wang, K; Wascko, M O; Westerhoff, S; Williams, D A; Yang, T; Yodh, G B

    2000-01-01

    Milagrito, a detector sensitive to very high energy gamma rays, monitored the northern sky from February 1997 through May 1998. With a large field of view and a high duty cycle, this instrument was well suited to perform a search for TeV gamma-ray bursts (GRBs). We report on a search made for TeV counterparts to GRBs observed by BATSE. BATSE detected 54 GRBs within the field of view of Milagrito during this period. An excess of events coincident in time and space with one of these bursts, GRB 970417a, was observed by Milagrito. The excess has a chance probability of $2.8 \\times 10^{-5}$ of being a fluctuation of the background. The probability for observing an excess at least this large from any of the 54 bursts is $1.5 \\times 10^{-3}$. No significant correlations were detected from the other bursts.

  2. Gamma-Ray Burst Prompt Emission

    CERN Document Server

    Zhang, Bing

    2014-01-01

    The origin of gamma-ray burst (GRB) prompt emission, bursts of gamma-rays lasting from shorter than one second to thousands of seconds, remains not fully understood after more than 40 years of observations. The uncertainties lie in several open questions in the GRB physics, including jet composition, energy dissipation mechanism, particle acceleration mechanism, and radiation mechanism. Recent broad-band observations of prompt emission with Fermi sharpen the debates in these areas, which stimulated intense theoretical investigations invoking very different ideas. I will review these debates, and argue that the current data suggest the following picture: A quasi-thermal spectral component originating from the photosphere of the relativistic ejecta has been detected in some GRBs. Even though in some cases (e.g. GRB 090902B) this component dominates the spectrum, in most GRBs, this component either forms a sub-dominant "shoulder" spectral component in the low energy spectral regime of the more dominant "Band" co...

  3. The optical identifcation of events with poorly defined locations: The case of the Fermi GBM GRB140801A

    CERN Document Server

    Lipunov, V M; Pruzhinskaya, M V; Postigo, A de Ugarte; Pelassa, V; Tsvetkova, A E; Sokolov, I V; Kann, D A; Xu, Dong; Gorbovskoy, E S; Krushinski, V V; Kornilov, V G; Balanutsa, P V; Boronina, S V; Budnev, N M; Cano, Z; Castro-Tirado, A J; Chazov, V V; Connaughton, V; Delvaux, C; Frederiks, D D; Fynbo, J F U; Gabovich, A V; Goldstein, A; Greiner, J; Gress, O A; Ivanov, K I; Jakobsson, P; Klose, S; Knust, F; Komarova, V N; Konstantinov, E; Krylov, A V; Kuvshinov, D A; Kuznetsov, A S; Lipunova, G V; Moskvitin, A S; Pal'shin, V D; Pandey, S B; Poleshchuk, V A; Schmidl, S; Sergienko, Yu P; Sinyakov, E V; Schulze, S; Sokolov, V V; Sokolova, T N; Sparre, M; Thone, C C; Tlatov, A G; Tyurina, N V; Ulanov, M V; Yazev, S A; Yurkov, V V

    2015-01-01

    We report the early discovery of the optical afterglow of gamma-ray burst (GRB) 140801A in the 137 deg$^2$ 3-$\\sigma$ error-box of the Fermi Gamma-ray Burst Monitor (GBM). MASTER is the only observatory that automatically react to all Fermi alerts. GRB 140801A is one of the few GRBs whose optical counterpart was discovered solely from its GBM localization. The optical afterglow of GRB 140801A was found by MASTER Global Robotic Net 53 sec after receiving the alert, making it the fastest optical detection of a GRB from a GBM error-box. Spectroscopy obtained with the 10.4-m Gran Telescopio Canarias and the 6-m BTA of SAO RAS reveals a redshift of $z=1.32$. We performed optical and near-infrared photometry of GRB 140801A using different telescopes with apertures ranging from 0.4-m to 10.4-m. GRB 140801A is a typical burst in many ways. The rest-frame bolometric isotropic energy release and peak energy of the burst is $E_\\mathrm{iso} = 5.54_{-0.24}^{+0.26} \\times 10^{52}$ erg and $E_\\mathrm{p, rest}\\simeq280$ keV,...

  4. SWIFT and BATSE bursts' classification

    CERN Document Server

    Horvath, I; Balazs, L G; Tusnady, G; Veres, P

    2009-01-01

    Two classes of gamma-ray bursts were identified in the BATSE catalogs characterized by their durations. There were also some indications for the existence of a third type of gamma-ray bursts. Swift satellite detectors have different spectral sensitivity than pre-Swift ones for GRBs. Therefore in this paper we analyze the bursts' duration distribution and also the duration-hardness bivariate distribution, published in The First BAT Catalog. Similarly to the BATSE data, to explain the BAT GRBs' duration distribution three components are needed. Although, the relative frequencies of the groups are different than they were in the BATSE GRB sample, the difference in the instrument spectral sensitivities can explain this bias in a natural way. This means theoretical models may have to explain three different type of gamma-ray bursts.

  5. The flux-E_p relation within GRB060218 in comparison with typical GRB pulses

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The prompt gamma-ray/X-ray emission of gamma-ray burst(GRB) 060218 was simultaneously observed by the Burst Alert Telescope(BAT) and X-ray Telescope(XRT) onboard Swift.Its peak energy of the joint νfν spectrum(Ep) clearly evolves with time from tens of keV to-1 keV,crossing both the BAT and XRT bands.The best fit yields log Ep=(4.61± 0.23)+(-1.29±0.08) log t,with a correlation coefficient of 0.98 and a chance probability of p<10-4.We derive its bolometric flux(F)in the 0.01-10 4 keV band,and find that its F-Ep relation,with a power-law index of 0.37,is much shallower than that observed in typical GRB pulses.Discussion of this shallowness is presented.

  6. Black hole central engine for ultra-long gamma-ray burst 111209A and its associated supernova 2011kl

    OpenAIRE

    Gao, He; Lei, Wei-Hua; You, Zhi-Qiang; Xie, Wei

    2016-01-01

    Recently, the first association between an ultra-long gamma-ray burst (GRB) and a supernova is reported, i.e., GRB 111209A/SN 2011kl, which enables us to investigate the physics of central engines or even progenitors for ultra-long GRBs. In this paper, we inspect the broad-band data of GRB 111209A/SN 2011kl. The late-time X-ray lightcurve exhibits a GRB 121027A-like fall-back bump, suggesting a black hole central engine. We thus propose a collapsar model with fall-back accretion for GRB 11120...

  7. The metallicity and dust content of a redshift 5 gamma-ray burst host galaxy

    DEFF Research Database (Denmark)

    Sparre, M.; Hartoog, O. E.; Krühler, T.;

    2014-01-01

    Observations of the afterglows of long gamma-ray bursts (GRBs) allow the study of star-forming galaxies across most of cosmic history. Here we present observations of GRB 111008A from which we can measure metallicity, chemical abundance patterns, dust-to-metals ratio and extinction of the GRB hos...

  8. An Exact Solution of the Gamma Ray Burst Arrival Time Analysis Problem

    Indian Academy of Sciences (India)

    S. Sinha

    2002-03-01

    An analytical solution of the GRB arrival time analysis is presented. The errors in the position of the GRB resulting from timing and position errors of different satellites are calculated. A simple method of cross-correlating gamma ray burst time-histories is discussed.

  9. A Fe K Line in GRB 970508

    Science.gov (United States)

    Protassov, R.; van Dyk, D.; Connors, A.; Kashyap, V.; Siemiginowska, A.

    2000-12-01

    We examine the x-ray spectrum of the afterglow of GRB 970508, analyzed for Fe line emission by Piro et al (1999, ApJL, 514, L73). This is a difficult and extremely important measurement: the detection of x-ray afterglows from γ -ray bursts is at best a tricky business, relying on near-real satellite time response to unpredictable events; and a great deal of luck in catching a burst bright enough for a useful spectral analysis. Detecting a clear atomic (or cyclotron) line in the generally smooth and featureless afterglow (or burst) emission not only gives one of the few very specific keys to the physics local to the emission region, but also provides clues or confirmation of its distance (via redshift). Unfortunately, neither the likelihood ratio test or the related F-statistic commonly used to detect spectral lines adhere to their nominal Chi square and F-distributions. Thus we begin by calibrating the F-statistic used in Piro et al (1999, ApJL, 514, L73) via a simulation study. The simulation study relies on a completely specified source model, i.e. we do Monte Carlo simulations with all model parameters fixed (so--called ``parametric bootstrapping''). Second, we employ the method of posterior predictive p-values to calibrate a LRT statistic while accounting for the uncertainty in the parameters of the source model. Our analysis reveals evidence for the Fe K line.

  10. Open Questions in GRB Physics

    OpenAIRE

    Zhang, Bing

    2011-01-01

    Open questions in GRB physics are summarized as of 2011, including classification, progenitor, central engine, ejecta composition, energy dissipation and particle acceleration mechanism, radiation mechanism, long term engine activity, external shock afterglow physics, origin of high energy emission, and cosmological setting. Prospects of addressing some of these problems with the upcoming Chinese-French GRB mission, SVOM, are outlined.

  11. Properties of GRB Lightcurves from Magnetic Reconnection

    Science.gov (United States)

    Beniamini, Paz; Granot, Jonathan

    2016-04-01

    The energy dissipation mechanism within Gamma-Ray Burst (GRB) outflows, driving their extremely luminous prompt γ-ray emission is still uncertain. The leading candidates are internal shocks and magnetic reconnection. While the emission from internal shocks has been extensively studied, that from reconnection still has few quantitative predictions. We study the expected prompt-GRB emission from magnetic reconnection and compare its temporal and spectral properties to observations. The main difference from internal shocks is that for reconnection one expects relativistic bulk motions with Lorentz factors Γ' ≳ a few in the jet's bulk frame. We consider such motions of the emitting material in two anti-parallel directions (e.g. of the reconnecting magnetic-field lines) within an ultra-relativistic (with Γ ≫ 1) thin spherical reconnection layer. The emission's relativistic beaming in the jet's frame greatly affects the light-curves. For emission at radii R0 tracking (for Γ' > 2). However, only the relativistic turbulence mode can naturally account also for the following correlations: luminosity-variability, peak luminosity - peak frequency and pulse width energy dependence / spectral lags.

  12. Search for strong gravitational lensing effect in the current GRB data of BATSE

    Science.gov (United States)

    Li, ChunYu; Li, LiXin

    2014-08-01

    Because gamma-ray bursts (GRBs) trace the high- z universe, there is an appreciable probability for a GRB to be gravitational lensed by galaxies in the universe. Herein we consider the gravitational lensing effect of GRBs contributed by the dark matter halos in galaxies. Assuming that all halos have the singular isothermal sphere (SIS) mass profile in the mass range 1010 h -1 M ⊙ distribution and luminosity function derived from the Swift LGRBs sample, we calculated the gravitational lensing probability in BATSE, Swift/BAT and Fermi/GBM GRBs, respectively. With an derived probability result in BATSE GRBs, we searched for lensed GRB pairs in the BATSE5B GRB Spectral catalog. The search did not find any convincing gravitationally lensed events. We discuss our result and future observations for GRB lensing observation.

  13. Afterglow from GRB 070610/Swift J195509.6+261406:An explanation using the fireball model

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    GRB 070610,which is also named Swift J195509.6+261406,is a peculiar Galactic transient with significant variability on short timescales in both X-ray and optical light curves.One possible explanation is that GRB 070610/Swift J195509.6 + 261406 is a soft gamma-ray repeater(SGR) in our Galaxy.Here,we use the fireball model,which is usually recognized as the standard model of gamma-ray burst(GRB) afterglows,and the energy injection hypothesis to interpret the X-ray and optical afterglow light curves of GRB 070610/Swift J195509.6 + 261406.It is found that the model is generally consistent with observations.

  14. Properties of GRB Lightcurves from Magnetic Reconnection

    CERN Document Server

    Beniamini, Paz

    2015-01-01

    The energy dissipation mechanism within Gamma ray bursts' (GRBs) ultra-relativistic outflows that drive the prompt $\\gamma$-ray emission remains uncertain. Two leading candidates are internal shocks and magnetic reconnection. While the emission from internal shocks has been extensively studied, that from reconnection still has few quantitative predictions. We study the prompt GRB emission from magnetic reconnection and compare its expected temporal and spectral properties to observations. The main difference from internal shocks is that for magnetic reconnection one expects relativistic bulk motions with a Lorentz factor of $\\Gamma'\\gtrsim$a few in the mean rest frame of the outflow - the comoving frame. We consider a thin spherical shell (or reconnection layer) expanding at a bulk Lorentz factor $\\Gamma\\gg 1$ in which the emitting material moves with $\\Gamma'$ in the comoving frame along this layer in two anti-parallel directions (e.g. of the reconnecting field lines). The resulting relativistic beaming of t...

  15. The future Gamma-Ray Burst Mission SVOM

    CERN Document Server

    Schanne, S; Wei, J; Zhang, S -N; Basa, S; Atteia, J -L; Barret, D; Claret, A; Cordier, B; Daigne, F; Godet, O; Götz, D; Mandrou, P

    2010-01-01

    We present the Space-based multi-band astronomical Variable Object Monitor (SVOM), a future satellite mission for Gamma-Ray Burst (GRB) studies, developed in cooperation between the Chinese National Space Agency (CNSA), the Chinese Academy of Science (CAS), the French Space Agency (CNES) and French research institutes. The scientific objectives of the SVOM GRB studies cover their classification (GRB diversity and unity of the model), their physics (particle acceleration and radiation mechanisms), their progenitors, cosmological studies (host galaxies, star formation history, re-ionization, cosmological parameters), and fundamental physics (origin of cosmic rays, Lorentz invariance, gravitational wave sources). From 2015 on, SVOM will provide fast and accurate localizations of all known types of GRB, and determine the temporal and spectral properties of the GRB emission, thanks to a set of four onboard instruments. The trigger system of the coded-mask telescope ECLAIRs onboard SVOM images the sky in the 4-120 ...

  16. THE DISCOVERY OF VIBRATIONALLY EXCITED H2 IN THE MOLECULAR CLOUD NEAR GRB 080607

    International Nuclear Information System (INIS)

    GRB 080607 has provided the first observational signatures of molecular absorption bands toward any galaxy hosting a gamma-ray burst (GRB). Despite the identification of dozens of features as belonging to various atomic and molecular (H2 and CO) carriers, many more absorption features remained unidentified. Here, we report on a search among these features for absorption from vibrationally excited H2, a species that was predicted to be produced by the UV flash of a GRB impinging on a molecular cloud. Following a detailed comparison between our spectroscopy and static, as well as dynamic, models of H2* absorption, we conclude that a column density of 1017.5±0.2 cm-2 of H2* was produced along the line of sight toward GRB 080607. Depending on the assumed amount of dust extinction between the molecular cloud and the GRB, the model distance between the two is found to be in the range 230-940 pc. Such a range is consistent with a conservative lower limit of 100 pc estimated from the presence of Mg I in the same data. These distances show that substantial molecular material is found within hundreds of pc from GRB 080607, part of the distribution of clouds within the GRB host galaxy.

  17. Identifying the host galaxy of the short GRB 100628A

    Science.gov (United States)

    Nicuesa Guelbenzu, A.; Klose, S.; Palazzi, E.; Greiner, J.; Michałowski, M. J.; Kann, D. A.; Hunt, L. K.; Malesani, D.; Rossi, A.; Savaglio, S.; Schulze, S.; Xu, D.; Afonso, P. M. J.; Elliott, J.; Ferrero, P.; Filgas, R.; Hartmann, D. H.; Krühler, T.; Knust, F.; Masetti, N.; Olivares E., F.; Rau, A.; Schady, P.; Schmidl, S.; Tanga, M.; Updike, A. C.; Varela, K.

    2015-11-01

    We report on the results of a comprehensive observing campaign to reveal the host galaxy of the short GRB 100628A. This burst was followed by a faint X-ray afterglow but no optical counterpart was discovered. However, inside the X-ray error circle a potential host galaxy at a redshift of z = 0.102 was soon reported in the literature. If this system is the host, then GRB 100628A was the cosmologically most nearby unambiguous short burst with a measured redshift so far. We used the multi-colour imager GROND at the ESO/La Silla MPG 2.2 m telescope, ESO/VLT spectroscopy, and deep Australia Telescope Compact Array (ATCA) radio-continuum observations together with publicly available Gemini imaging data to study the putative host and the galaxies in the field of GRB 100628A. We confirm that inside the X-ray error circle the most probable host-galaxy candidate is the morphologically disturbed, interacting galaxy system at z = 0.102. The interacting galaxies are connected by a several kpc long tidal stream, which our VLT/FORS2 spectroscopy reveals strong emission lines of [O ii], [O iii], Hα and Hβ, characteristic for the class of extreme emission-line galaxies and indicative of ongoing star formation. The latter leaves open the possibility that the GRB progenitor was a member of a young stellar population. However, we indentify a second host-galaxy candidate slightly outside the X-ray error circle. It is a radio-bright, luminous elliptical galaxy at a redshift z = 0.311. With a K-band luminosity of 2 × 1011L⊙ this galaxy resembles the probable giant elliptical host of the first well-localized short burst, GRB 050509B. If this is the host, then the progenitor of GRB 100628A was a member of an old stellar population. Based on observations collected at the Very Large Telescope of the European Southern Observatory, Paranal, Chile (ESO programme 087.D-0503 and 290.D-5194; PI: A. Nicuesa Guelbenzu; 090.A-0825; PI: D. Malesani), GROND (PI: J. Greiner), and ATCA (Program C

  18. An Artificial Intelligence Classification Tool and Its Application to Gamma-Ray Bursts

    Science.gov (United States)

    Hakkila, Jon; Haglin, David J.; Roiger, Richard J.; Giblin, Timothy; Paciesas, William S.; Pendleton, Geoffrey N.; Mallozzi, Robert S.

    2004-01-01

    Despite being the most energetic phenomenon in the known universe, the astrophysics of gamma-ray bursts (GRBs) has still proven difficult to understand. It has only been within the past five years that the GRB distance scale has been firmly established, on the basis of a few dozen bursts with x-ray, optical, and radio afterglows. The afterglows indicate source redshifts of z=1 to z=5, total energy outputs of roughly 10(exp 52) ergs, and energy confined to the far x-ray to near gamma-ray regime of the electromagnetic spectrum. The multi-wavelength afterglow observations have thus far provided more insight on the nature of the GRB mechanism than the GRB observations; far more papers have been written about the few observed gamma-ray burst afterglows in the past few years than about the thousands of detected gamma-ray bursts. One reason the GRB central engine is still so poorly understood is that GRBs have complex, overlapping characteristics that do not appear to be produced by one homogeneous process. At least two subclasses have been found on the basis of duration, spectral hardness, and fluence (time integrated flux); Class 1 bursts are softer, longer, and brighter than Class 2 bursts (with two second durations indicating a rough division). A third GRB subclass, overlapping the other two, has been identified using statistical clustering techniques; Class 3 bursts are intermediate between Class 1 and Class 2 bursts in brightness and duration, but are softer than Class 1 bursts. We are developing a tool to aid scientists in the study of GRB properties. In the process of developing this tool, we are building a large gamma-ray burst classification database. We are also scientifically analyzing some GRB data as we develop the tool. Tool development thus proceeds in tandem with the dataset for which it is being designed. The tool invokes a modified KDD (Knowledge Discovery in Databases) process, which is described as follows.

  19. Gamma Ray Burst progenitors - a case for helium star mergers

    OpenAIRE

    Belczynski, Krzysztof; Bulik, Tomasz; Rudak, Bronislaw

    2000-01-01

    Recently much work in Gamma-Ray Burst (GRB) studies was devoted to revealing the nature of outburst mechanism and to looking for GRB progenitors. Several types of progenitors were proposed for GRBs. Most promising objects are collapsars, compact object binaries, Helium star mergers and recently discussed supernovae. In this paper we consider four proposed binary star progenitors of GRBs: double neutron star (NS-NS), black hole neutron star (BH-NS), black hole white dwarf (BH-WD) mergers and H...

  20. The interplanetary gamma ray burst network

    Science.gov (United States)

    Cline, T.

    The Interplanetary Gamma-Ray Burst Network (IPN) is providing gamma-ray burst (GRB) alerts and localizations at the maximum rate anticipated before the launch of the Swift mission. The arc-minute source precision of the IPN is again permitting searches for GRB afterglows in the radio and optical regimes with delays of only hours up to 2 days. The successful addition of the Mars Odyssey mission has compensated for the loss of the asteroid mission NEAR, to reconstitute a fully long- baseline interplanetary network, with Ulysses at > 5 AU and Konus-Wind and HETE-2 near the Earth. In addition to making unassisted GRB localizations that enable a renewed supply of counterpart observations, the Mars/Ulysses/Wind IPN is confirming and reinforcing GRB source localizations with HETE-2. It has also confirmed and reinforced localizations with the BeppoSAX mission before the BeppoSAX termination in May and has detected and localized both SGRs and an unusual hard x-ray transient that is neither an SGR nor a GRB. This IPN is expected to operate until at least 2004.

  1. Open issues in gamma-ray bursts: polarimetry and dark GRBs

    OpenAIRE

    Malesani, D.; S. Covino(INAF - Oss. Astronomico di Brera); Rossi, E. M.; Lazzati, D.; A. De Luca; Filliatre, P.; Tagliaferri, G.

    2005-01-01

    We review some open problems in the physics of afterglows, namely their polarization properties and the existence of dark/faint bursts. Polarization studies yield precious insights in the physical structure and dynamical evolution of GRB jets, revealing their magnetization properties and their energy profile. Polarimetric observations of GRB 020813 already allowed to exclude a homogeneous jet for this event. We then present observations of faint/dark bursts, showing that some of them may be o...

  2. Neutrino, Neutron, and Cosmic Ray Production in the External Shock Model of Gamma Ray Bursts

    OpenAIRE

    Dermer, Charles D.

    2000-01-01

    The hypothesis that ultra-high energy (>~ 10^19 eV) cosmic rays (UHECRs) are accelerated by gamma-ray burst (GRB) blast waves is assumed to be correct. Implications of this assumption are then derived for the external shock model of gamma-ray bursts. The evolving synchrotron radiation spectrum in GRB blast waves provides target photons for the photomeson production of neutrinos and neutrons. Decay characteristics and radiative efficiencies of the neutral particles that escape from the blast w...

  3. The distribution of equivalent widths in long GRB afterglow spectra

    CERN Document Server

    Postigo, A de Ugarte; Thoene, C C; Christensen, L; Gorosabel, J; Milvang-Jensen, B; Schulze, S; Jakobsson, P; Wiersema, K; Sanchez-Ramirez, R; Leloudas, G; Zafar, T; Malesani, D; Hjorth, J

    2012-01-01

    The extreme brightness of gamma-ray burst (GRB) afterglows and their simple spectral shape make them ideal beacons to study the interstellar medium of their host galaxies through absorption line spectroscopy. Using 69 low-resolution GRB afterglow spectra, we conduct a study of the rest-frame equivalent width (EW) distribution of features with an average rest-frame EW larger than 0.5 A. To compare an individual GRB with the sample, we develop EW diagrams as a graphical tool, and we give a catalogue with diagrams for the 69 spectra. We introduce a line strength parameter (LSP) that allows us to quantify the strength of the absorption features as compared to the sample by a single number. Using the distributions of EWs of single-species features, we derive the distribution of column densities by a curve of growth (CoG) fit. We find correlations between the LSP and the extinction of the GRB, the UV brightness of the host galaxies and the neutral hydrogen column density. However, we see no significant evolution of...

  4. Effects of Beyond Standard Model Physics on GRB Neutrinos

    CERN Document Server

    Moharana, Reetanjali

    2013-01-01

    The nondetection of neutrinos coming from Gamma Ray Bursts (GRBs) by the IceCube experiment has raised serious questions on our understanding of GRB's and the mechanism of neutrino flux production in them. Motivated by this and the need for a precise calculation for GRB neutrino flux, here we study the effects of beyond standard model physics on the GRB neutrino flux. In the internal shock model of GRB, high energy neutrinos are expected from muon, pion and kaon decays. Using the latest best fit neutrino oscillation parameters, we compute the expected flux on earth for standard as well as non-standard oscillation scenarios. Among the non-standard scenarios, we consider neutrino decay, pseudo-dirac nature of neutrinos and presence of one eV scale light sterile neutrino. Incorporating other experimental bounds on these new physics scenarios, we show that neutrino decay scenario can significantly alter the neutrino flux on earth from the expected ones whereas the corresponding changes for pseudo-dirac and steril...

  5. IMPLICATIONS FOR THE ORIGIN OF GRB 051103 FROM LIGO OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Abadie, J.; Abbott, B. P.; Abbott, R.; Adhikari, R.; Ajith, P.; Anderson, S. B.; Arai, K.; Araya, M. C. [LIGO-California Institute of Technology, Pasadena, CA 91125 (United States); Abbott, T. D. [California State University Fullerton, Fullerton, CA 92831 (United States); Abernathy, M. [University of Glasgow, Glasgow G12 8QQ (United Kingdom); Adams, C. [LIGO-Livingston Observatory, Livingston, LA 70754 (United States); Affeldt, C.; Allen, B. [Albert-Einstein-Institut, Max-Planck-Institut fuer Gravitationsphysik, D-30167 Hannover (Germany); Allen, G. S. [Stanford University, Stanford, CA 94305 (United States); Ceron, E. Amador; Anderson, W. G. [University of Wisconsin-Milwaukee, Milwaukee, WI 53201 (United States); Amariutei, D.; Arain, M. A. [University of Florida, Gainesville, FL 32611 (United States); Amin, R. S. [Louisiana State University, Baton Rouge, LA 70803 (United States); Aston, S. M. [University of Birmingham, Birmingham B15 2TT (United Kingdom); Collaboration: LIGO Collaboration; and others

    2012-08-10

    We present the results of a LIGO search for gravitational waves (GWs) associated with GRB 051103, a short-duration hard-spectrum gamma-ray burst (GRB) whose electromagnetically determined sky position is coincident with the spiral galaxy M81, which is 3.6 Mpc from Earth. Possible progenitors for short-hard GRBs include compact object mergers and soft gamma repeater (SGR) giant flares. A merger progenitor would produce a characteristic GW signal that should be detectable at a distance of M81, while GW emission from an SGR is not expected to be detectable at that distance. We found no evidence of a GW signal associated with GRB 051103. Assuming weakly beamed {gamma}-ray emission with a jet semi-angle of 30 Degree-Sign , we exclude a binary neutron star merger in M81 as the progenitor with a confidence of 98%. Neutron star-black hole mergers are excluded with >99% confidence. If the event occurred in M81, then our findings support the hypothesis that GRB 051103 was due to an SGR giant flare, making it one of the most distant extragalactic magnetars observed to date.

  6. Implications For The Origin Of GRB 051103 From LIGO Observations

    CERN Document Server

    Abadie, J; Abbott, T D; Abbott, R; Abernathy, M; Adams, C; Adhikari, R; Affeldt, C; Ajith, P; Allen, B; Allen, G S; Ceron, E Amador; Amariutei, D; Amin, R S; Anderson, S B; Anderson, W G; Arai, K; Arain, M A; Araya, M C; Aston, S M; Atkinson, D; Aufmuth, P; Aulbert, C; Aylott, B E; Babak, S; Baker, P; Ballmer, S; Barker, D; Barnum, S; Barr, B; Barriga, P; Barsotti, L; Barton, M A; Bartos, I; Bassiri, R; Bastarrika, M; Bauchrowitz, J; Behnke, B; Bell, A S; Belopolski, I; Benacquista, M; Bertolini, A; Betzwieser, J; Beveridge, N; Beyersdorf, P T; Bilenko, I A; Billingsley, G; Birch, J; Biswas, R; Black, E; Blackburn, J K; Blackburn, L; Blair, D; Bland, B; Bock, O; Bodiya, T P; Bogan, C; Bondarescu, R; Bork, R; Born, M; Bose, S; Boyle, M; Brady, P R; Braginsky, V B; Brau, J E; Breyer, J; Bridges, D O; Brinkmann, M; Britzger, M; Brooks, A F; Brown, D A; Brummitt, A; Buonanno, A; Burguet-Castell, J; Burmeister, O; Byer, R L; Cadonati, L; Camp, J B; Campsie, P; Cannizzo, J; Cannon, K; Cao, J; Capano, C; Caride, S; Caudill, S; Cavaglia, M; Cepeda, C; Chalermsongsak, T; Chalkley, E; Charlton, P; Chelkowski, S; Chen, Y; Christensen, N; Chua, S S Y; Chung, S; Chung, C T Y; Clara, F; Clark, D; Clark, J; Clayton, J H; Conte, R; Cook, D; Corbitt, T R C; Cornish, N; Costa, C A; Coughlin, M; Coward, D M; Coyne, D C; Creighton, J D E; Creighton, T D; Cruise, A M; Cumming, A; Cunningham, L; Culter, R M; Dahl, K; Danilishin, S L; Dannenberg, R; Danzmann, K; Das, K; Daudert, B; Daveloza, H; Davies, G; Daw, E J; Dayanga, T; DeBra, D; Degallaix, J; Dent, T; Dergachev, V; DeRosa, R; DeSalvo, R; Dhurandhar, S; Di Palma, I; Diaz, M; Donovan, F; Dooley, K L; Dorsher, S; Douglas, E S D; Drever, R W P; Driggers, J C; Dumas, J -C; Dwyer, S; Eberle, T; Edgar, M; Edwards, M; Effler, A; Ehrens, P; Engel, R; Etzel, T; Evans, M; Evans, T; Factourovich, M; Fairhurst, S; Fan, Y; Farr, B F; Fazi, D; Fehrmann, H; Feldbaum, D; Finn, L S; Flanigan, M; Foley, S; Forsi, E; Fotopoulos, N; Frede, M; Frei, M; Frei, Z; Freise, A; Frey, R; Fricke, T T; Friedrich, D; Fritschel, P; Frolov, V V; Fulda, P; Fyffe, M; Garcia, J; Garofoli, J A; Gholami, I; Ghosh, S; Giaime, J A; Giampanis, S; Giardina, K D; Gill, C; Goetz, E; Goggin, L M; Gonzalez, G; Gorodetsky, M L; Gossler, S; Graef, C; Grant, A; Gras, S; Gray, C; Greenhalgh, R J S; Gretarsson, A M; Grosso, R; Grote, H; Grunewald, S; Guido, C; Gupta, R; Gustafson, E K; Gustafson, R; Hage, B; Hallam, J M; Hammer, D; Hammond, G; Hanks, J; Hanna, C; Hanson, J; Harms, J; Harry, G M; Harry, I W; Harstad, E D; Hartman, M T; Haughian, K; Hayama, K; Heefner, J; Hendry, M A; Heng, I S; Heptonstall, A W; Herrera, V; Hewitson, M; Hild, S; Hoak, D; Hodge, K A; Holt, K; Hong, T; Hooper, S; Hosken, D J; Hough, J; Howell, E J; Hughey, B; Husa, S; Huttner, S H; Ingram, D R; Inta, R; Isogai, T; Ivanov, A; Johnson, W W; Jones, D I; Jones, G; Jones, R; Ju, L; Kalmus, P; Kalogera, V; Kandhasamy, S; Kanner, J B; Katsavounidis, E; Katzman, W; Kawabe, K; Kawamura, S; Kawazoe, F; Kells, W; Kelner, M; Keppel, D G; Khalaidovski, A; Khalili, F Y; Khazanov, E A; Kim, N; Kim, H; King, P J; Kinzel, D L; Kissel, J S; Klimenko, S; Kondrashov, V; Kopparapu, R; Koranda, S; Korth, W Z; Kozak, D; Kringel, V; Krishnamurthy, S; Krishnan, B; Kuehn, G; Kumar, R; Kwee, P; Landry, M; Lantz, B; Lastzka, N; Lazzarini, A; Leaci, P; Leong, J; Leonor, I; Li, J; Lindquist, P E; Lockerbie, N A; Lodhia, D; Lormand, M; Lu, P; Luan, J; Lubinski, M; Luck, H; Lundgren, A P; Macdonald, E; Machenschalk, B; MacInnis, M; Mageswaran, M; Mailand, K; Mandel, I; Mandic, V; Marandi, A; Marka, S; Marka, Z; Maros, E; Martin, I W; Martin, R M; Marx, J N; Mason, K; Matichard, F; Matone, L; Matzner, R A; Mavalvala, N; McCarthy, R; McClelland, D E; McGuire, S C; McIntyre, G; McIver, J; McKechan, D J A; Meadors, G; Mehmet, M; Meier, T; Melatos, A; Melissinos, A C; Mendell, G; Mercer, R A; Meshkov, S; Messenger, C; Meyer, M S; Miao, H; Miller, J; Mino, Y; Mitrofanov, V P; Mitselmakher, G; Mittleman, R; Miyakawa, O; Moe, B; Moesta, P; Mohanty, S D; Moraru, D; Moreno, G; Mossavi, K; Mow-Lowry, C M; Mueller, G; Mukherjee, S; Mullavey, A; Muller-Ebhardt, H; Munch, J; Murphy, D; Murray, P G; Nash, T; Nawrodt, R; Nelson, J; Newton, G; Nishizawa, A; Nolting, D; Nuttall, L; O'Reilly, B; O'Shaughnessy, R; Ochsner, E; O'Dell, J; Ogin, G H; Oldenburg, R G; Osthelder, C; Ott, C D; Ottaway, D J; Ottens, R S; Overmier, H; Owen, B J; Page, A; Pan, Y; Pankow, C; Papa, M A; Patel, P; Pedraza, M; Pekowsky, L; Penn, S; Peralta, C; Perreca, A; Phelps, M; Pickenpack, M; Pinto, I M; Pitkin, M; Pletsch, H J; Plissi, M V; Podkaminer, J; Pold, J; Postiglione, F; Predoi, V; Price, L R; Prijatelj, M; Principe, M; Privitera, S; Prix, R; Prokhorov, L; Puncken, O; Quetschke, V; Raab, F J; Radkins, H; Raffai, P; Rakhmanov, M; Ramet, C R; Rankins, B; Mohapatra, S R P; Raymond, V; Redwine, K; Reed, C M; Reed, T; Reid, S; Reitze, D H; Riesen, R; Riles, K; Roberts, P; Robertson, N A; Robinson, C; Robinson, E L; Roddy, S; Rollins, J; Romano, J D; Romie, J H; Rover, C; Rowan, S; Rudiger, A; Ryan, K; Sakata, S; Sakosky, M; Salemi, F; Salit, M; Sammut, L; de la Jordana, L Sancho; Sandberg, V; Sannibale, V; SantamarÌa, L; Santiago-Prieto, I; Santostasi, G; Saraf, S; Sathyaprakash, B S; Sato, S; Saulson, P R; Savage, R; Schilling, R; Schlamminger, S; Schnabel, R; Schofield, R M S; Schulz, B; Schutz, B F; Schwinberg, P; Scott, J; Scott, S M; Searle, A C; Seifert, F; Sellers, D; Sengupta, A S; Sergeev, A; Shaddock, D A; Shaltev, M; Shapiro, B; Shawhan, P; Weerathunga, T Shihan; Shoemaker, D H; Sibley, A; Siemens, X; Sigg, D; Singer, A; Singer, L; Sintes, A M; Skelton, G; Slagmolen, B J J; Slutsky, J; Smith, R; Smith, J R; Smith, M R; Smith, N D; Somiya, K; Sorazu, B; Soto, J; Speirits, F C; Stein, A J; Steinlechner, J; Steinlechner, S; Steplewski, S; Stefszky, M; Stochino, A; Stone, R; Strain, K A; Strigin, S; Stroeer, A S; Stuver, A L; Summerscales, T Z; Sung, M; Susmithan, S; Sutton, P J; Szokoly, G P; Talukder, D; Tanner, D B; Tarabrin, S P; Taylor, J R; Taylor, R; Thomas, P; Thorne, K A; Thorne, K S; Thrane, E; Thuring, A; Tokmakov, K V; Torres, C; Torrie, C I; Traylor, G; Trias, M; Tseng, K; Ugolini, D; Urbanek, K; Vahlbruch, H; Vaishnav, B; Vallisneri, M; Broeck, C Van Den; van der Sluys, M V; van Veggel, A A; Vass, S; Vaulin, R; Vecchio, A; Veitch, J; Veitch, P J; Veltkamp, C; Villar, A E; Vorvick, C; Vyachanin, S P; Waldman, S J; Wallace, L; Wanner, A; Ward, R L; Wei, P; Weinert, M; Weinstein, A J; Weiss, R; Wen, L; Wen, S; Wessels, P; West, M; Westphal, T; Wette, K; Whelan, J T; Whitcomb, S E; White, D; Whiting, B F; Wilkinson, C; Willems, P A; Williams, H R; Williams, L; Willke, B; Winkelmann, L; Winkler, W; Wipf, C C; Wiseman, A G; Woan, G; Wooley, R; Worden, J; Yablon, J; Yakushin, I; Yamamoto, K; Yamamoto, H; Yang, H; Yeaton-Massey, D; Yoshida, S; Yu, P; Zanolin, M; Zhang, L; Zhang, Z; Zhao, C; Zotov, N; Zucker, M E; Zweizig, J; Bizouard, M A; Dietz, A; Guidi, G M; Was, M

    2012-01-01

    We present the results of a LIGO search for gravitational waves (GWs) associated with GRB 051103, a short-duration hard-spectrum gamma-ray burst (GRB) whose electromagnetically determined sky position is coincident with the spiral galaxy M81, which is 3.6 Mpc from Earth. Possible progenitors for short-hard GRBs include compact object mergers and soft gamma repeater (SGR) giant flares. A merger progenitor would produce a characteristic GW signal that should be detectable at the distance of M81, while GW emission from an SGR is not expected to be detectable at that distance. We found no evidence of a GW signal associated with GRB 051103. Assuming weakly beamed gamma-ray emission with a jet semi-angle of 30 deg we exclude a binary neutron star merger in M81 as the progenitor with a confidence of 98%. Neutron star-black hole mergers are excluded with > 99% confidence. If the event occurred in M81 our findings support the the hypothesis that GRB 051103 was due to an SGR giant flare, making it the most distant extr...

  7. The optical identification of events with poorly defined locations: the case of the Fermi GBM GRB 140801A

    Science.gov (United States)

    Lipunov, V. M.; Gorosabel, J.; Pruzhinskaya, M. V.; Postigo, A. de Ugarte; Pelassa, V.; Tsvetkova, A. E.; Sokolov, I. V.; Kann, D. A.; Xu, Dong; Gorbovskoy, E. S.; Krushinski, V. V.; Kornilov, V. G.; Balanutsa, P. V.; Boronina, S. V.; Budnev, N. M.; Cano, Z.; Castro-Tirado, A. J.; Chazov, V. V.; Connaughton, V.; Delvaux, C.; Frederiks, D. D.; Fynbo, J. F. U.; Gabovich, A. V.; Goldstein, A.; Greiner, J.; Gress, O. A.; Ivanov, K. I.; Jakobsson, P.; Klose, S.; Knust, F.; Komarova, V. N.; Konstantinov, E.; Krylov, A. V.; Kuvshinov, D. A.; Kuznetsov, A. S.; Lipunova, G. V.; Moskvitin, A. S.; Pal'shin, V. D.; Pandey, S. B.; Poleshchuk, V. A.; Schmidl, S.; Sergienko, Yu. P.; Sinyakov, E. V.; Schulze, S.; Sokolov, V. V.; Sokolova, T. N.; Sparre, M.; Thöne, C. C.; Tlatov, A. G.; Tyurina, N. V.; Ulanov, M. V.; Yazev, S. A.; Yurkov, V. V.

    2016-01-01

    We report the early discovery of the optical afterglow of gamma-ray burst (GRB) 140801A in the 137 deg2 3-σ error-box of the Fermi Gamma-ray Burst Monitor (GBM). MASTER is the only observatory that automatically reacts to all Fermi alerts. GRB 140801A is one of the few GRBs whose optical counterpart was discovered solely from its GBM localization. The optical afterglow of GRB 140801A was found by MASTER Global Robotic Net 53 s after receiving the alert, making it the fastest optical detection of a GRB from a GBM error-box. Spectroscopy obtained with the 10.4-m Gran Telescopio Canarias and the 6-m Big Telescope Alt-azimuth of the Special Astrophysical Observatory of the Russian Academy of Sciences reveals a redshift of z = 1.32. We performed optical and near-infrared photometry of GRB 140801A using different telescopes with apertures ranging from 0.4 to 10.4 m. GRB 140801A is a typical burst in many ways. The rest-frame bolometric isotropic energy release and peak energy of the burst are E_iso = 5.54_{-0.24}^{+0.26} {×} 10^{52} erg and Ep, rest ≃ 280 keV, respectively, which is consistent with the Amati relation. The absence of a jet break in the optical light curve provides a lower limit on the half-opening angle of the jet θ = 6.1°. The observed Epeak is consistent with the limit derived from the Ghirlanda relation. The joint Fermi GBM and Konus-Wind analysis show that GRB 140801A could belong to the class of intermediate duration. The rapid detection of the optical counterpart of GRB 140801A is especially important regarding the upcoming experiments with large coordinate error-box areas.

  8. Probing the cosmic gamma-ray burst rate with trigger simulations of the swift burst alert telescope

    International Nuclear Information System (INIS)

    The gamma-ray burst (GRB) rate is essential for revealing the connection between GRBs, supernovae, and stellar evolution. Additionally, the GRB rate at high redshift provides a strong probe of star formation history in the early universe. While hundreds of GRBs are observed by Swift, it remains difficult to determine the intrinsic GRB rate due to the complex trigger algorithm of Swift. Current studies of the GRB rate usually approximate the Swift trigger algorithm by a single detection threshold. However, unlike the previously flown GRB instruments, Swift has over 500 trigger criteria based on photon count rate and an additional image threshold for localization. To investigate possible systematic biases and explore the intrinsic GRB properties, we develop a program that is capable of simulating all the rate trigger criteria and mimicking the image threshold. Our simulations show that adopting the complex trigger algorithm of Swift increases the detection rate of dim bursts. As a result, our simulations suggest that bursts need to be dimmer than previously expected to avoid overproducing the number of detections and to match with Swift observations. Moreover, our results indicate that these dim bursts are more likely to be high redshift events than low-luminosity GRBs. This would imply an even higher cosmic GRB rate at large redshifts than previous expectations based on star formation rate measurements, unless other factors, such as the luminosity evolution, are taken into account. The GRB rate from our best result gives a total number of 4568−1429+825 GRBs per year that are beamed toward us in the whole universe.

  9. Probing the Cosmic Gamma-Ray Burst Rate with Trigger Simulations of the Swift Burst Alert Telescope

    Science.gov (United States)

    Lien, Amy; Sakamoto, Takanori; Gehrels, Neil; Palmer, David M.; Barthelmy, Scott D.; Graziani, Carlo; Cannizzo, John K.

    2013-01-01

    The gamma-ray burst (GRB) rate is essential for revealing the connection between GRBs, supernovae and stellar evolution. Additionally, the GRB rate at high redshift provides a strong probe of star formation history in the early universe. While hundreds of GRBs are observed by Swift, it remains difficult to determine the intrinsic GRB rate due to the complex trigger algorithm of Swift. Current studies of the GRB rate usually approximate the Swift trigger algorithm by a single detection threshold. However, unlike the previously own GRB instruments, Swift has over 500 trigger criteria based on photon count rate and additional image threshold for localization. To investigate possible systematic biases and explore the intrinsic GRB properties, we develop a program that is capable of simulating all the rate trigger criteria and mimicking the image threshold. Our simulations show that adopting the complex trigger algorithm of Swift increases the detection rate of dim bursts. As a result, our simulations suggest bursts need to be dimmer than previously expected to avoid over-producing the number of detections and to match with Swift observations. Moreover, our results indicate that these dim bursts are more likely to be high redshift events than low-luminosity GRBs. This would imply an even higher cosmic GRB rate at large redshifts than previous expectations based on star-formation rate measurements, unless other factors, such as the luminosity evolution, are taken into account. The GRB rate from our best result gives a total number of 4568 +825 -1429 GRBs per year that are beamed toward us in the whole universe.

  10. GRB 131231A: IMPLICATIONS OF THE GeV EMISSION

    International Nuclear Information System (INIS)

    GRB 131231A was detected by the Large Area Telescope on board the Fermi Space Gamma-ray Telescope. The high-energy gamma-ray (>100 MeV) afterglow emission spectrum is F ν∝ν–0.54 ± 0.15 in the first ∼1300 s after the trigger and the most energetic photon has an energy of ∼62 GeV, arriving at t ∼ 520 s. With reasonable parameters of the gamma-ray burst (GRB) outflow as well as the density of the circum-burst medium, the synchrotron radiation of electrons or protons accelerated at an external forward shock have difficulty accounting for the data. Rather, the synchrotron self-Compton radiation of the forward shock-accelerated electrons can account for both the spectrum and temporal behavior of the GeV afterglow emission. We also show that the prospect for detecting GRB 131231A-like GRBs with the Cherenkov Telescope Array is promising

  11. Primordial Black Holes and the Asymmetrical Distribution of Short GRB Events

    OpenAIRE

    Cline, David B.

    2001-01-01

    We review some of the expectations for Primordial Black Hole evaporation and we review the properties of short Gamma Ray Bursts. It is plausible that these GRB come from PBH evaporation. We then show that the angular distribution asymmetry recently observed by us could be due to a concentration of PBH in the Galactic Arms like the Orion arm.

  12. The extraordinarily bright optical afterglow of GRB 991208 and its host galaxy

    DEFF Research Database (Denmark)

    Castro-Tirado, A.J.; Sokolov, V.V.; Gorosabel, J.; Ceron, J.M.C.; Greiner, J.; Wijers, R.A.M.J.; Jensen, B.L.; Hjorth, J.; Toft, Søren; Pedersen, H.; Palazzi, E.; Pian, E.; Masetti, N.; Sagar, R.N.; Mohan, V.; Pandey, A.K.; Pandey, S.B.; Dodonov, S.N.; Fatkhullin, T.A.; Afanasiev, V.L.; Komarova, V.N.; Moiseev, A.V.; Hudec, R.; Simon, V.; Vreeswijk, P.; Rol, E.; Klose, S.; Stecklum, B.; Zapatero-Osorio, M.R.; Caon, N.; Blake, C.; Wall, J.; Heinlein, D.; Henden, A.; Benetti, S.; Magazzu, A.; Ghinassi, F.; Tommasi, L.; Bremer, M.; Kouveliotou, C.; Guziy, S.; Shlyapnikov, A.; Hopp, U.; Feulner, G.; Dreizler, S.; Hartmann, D.; Boehnhardt, H.; Paredes, J.M.; Marti, J.; Xanthopoulos, E.; Kristen, H.E.; Smoker, J.; Hurley, K.

    2001-01-01

    Broad-band optical observations of the extraordinarily bright optical afterglow of the intense gamma-rag burst GRB 991208 started similar to2.1 days after the event and continued until 4 Apr. 2000. The flux decay constant of the optic al afterglow in the R-band is -2.30 +/- 0.07 up to similar to5...

  13. Discovery of the optical counterpart and early optical observations of GRB 990712

    DEFF Research Database (Denmark)

    Sahu, K.C.; Vreesvijk, P.; Bakos, G.; Wenzies, J.W.; Bragaglia, A.; Frontera, F.; Piro, L.; Albrow, M.D.; Bond, I.A.; Bower, R.; Caldwell, J.A.R.; Castro-Tirado, A.J.; Courbin, F.; Dominik, M.; Fynbo, J.U.; Galama, T.; Glazebrook, K.; Greenhill, J.; Gorosabel, J.; Hearnshaw,, J.; Hill, K.; Hjorth, J.; Kane, S.; Kilmartin, P.; Kouveliotou, C.; Martin, R.; Masetti, N.; Maxted, P.; Minniti, D.; Moller, P.; Muraki, Y.; Nakamura, T.; Noda, S.; Ohnishi, K.; Palazzi, E.; van Paradijs, J.; Pian, E.; Pollard, K.R.; Rattenbury, N.J.; Reid, M.; Rol, E.; Saito, T.; Sackett, P.D.; Salzar, P.; Tinney, C.; Vermaak, P.; Watson, R.; Williams, A.; Yock, P.; Dar, A.

    2000-01-01

    We present the discovery observations of the optical counterpart of the gamma-ray burst GRB 990712 taken 4.16 hr after the outburst and discuss its light curve observed in the V, R, and I bands during the first similar to 35 days after the outburst. The observed light curves were fitted with a po...

  14. Time-dependent excitation and ionization modelling of absorption-line variability due to GRB080310

    DEFF Research Database (Denmark)

    Vreeswijk, P.M.; De Cia, A.; Jakobsson, P.;

    2013-01-01

    We model the time-variable absorption of Feii, Feiii, Siii, Cii and Crii detected in Ultraviolet and Visual Echelle Spectrograph (UVES) spectra of gamma-ray burst (GRB) 080310, with the afterglow radiation exciting and ionizing the interstellar medium in the host galaxy at a redshift of z = 2.427...

  15. GRB 150101B/ Swift J123205.1-105602: Second epoch Chandra observations

    Science.gov (United States)

    Levan, A. J.; Hjorth, J.; Tanvir, N. R.; van der Horst, A. J.

    2015-02-01

    We obtained a second epoch of observations of the very short GRB 150101B/ Swift J123205.1-105602 (Cummings et al. GCN 17267) with Chandra. Observations began on 10 Feb 2015, 39 days after the burst, and 32 days after the first epoch of observations.

  16. The rapidly flaring afterglow of the very bright and energetic GRB 070125

    NARCIS (Netherlands)

    A.C. Updike; J.B. Haislip; M.C. Nysewander; A.S. Fruchter; D.A. Kann; S. Klose; P.A. Milne; G.G. Williams; W. Zheng; C.W. Hergenrother; J.X. Prochaska; J.P. Halpern; N. Mirabal; J.R. Thorstensen; A.J. van der Horst; R.L.C. Starling; J.L. Racusin; D.N. Burrows; N.P.M. Kuin; P.W.A. Roming; E. Bellm; K. Hurley; W. Li; A.V. Filippenko; C. Blake; D. Starr; E.E. Falco; W.R. Brown; X. Dai; J. Deng; L. Xin; Y. Qiu; J. Wei; Y. Urata; D. Nanni; E. Maiorano; E. Palazzi; G. Greco; C. Bartolini; A. Guarnieri; A. Piccioni; G. Pizzichini; F. Terra; K. Misra; B.C. Bhatt; G.C. Anupama; X. Fan; L. Jiang; R.A.M.J. Wijers; D.E. Reichart; H.A. Eid; G. Bryngelson; J. Puls; R.C. Goldthwaite; D.H. Hartmann

    2008-01-01

    We report on multiwavelength observations, ranging from X-ray to radio wave bands, of the IPN-localized gamma-ray burst GRB 070125. Spectroscopic observations reveal the presence of absorption lines due to O I, Si II, and C IV, implying a likely redshift of z = 1.547. The well-sampled light curves,

  17. Radio and optical follow-up observations and improved interplanetary network position of GRB 970111

    NARCIS (Netherlands)

    Galama, TJ; Groot, PJ; Strom, RG; vanParadijs, J; Hurley, K; Kouveliotou, C; Fishman, GJ; Meegan, CA; Heise, J; intZand, JJM; deBruyn, AG; Hanlon, LO; Bennett, K; Telting, JH; Rutten, RGM

    1997-01-01

    We report on Westerbork 840 MHz and 1.4 and 5 GHz radio observations of the improved Interplanetary Network Wide Field Camera (IPN WFC) error box of the gamma-ray burst GRB 970111, between 26.4 hr and 120 days after the event onset. In the similar to 13 arcmin(2) area defined by the IPN (BATSE and U

  18. Optical and near-infrared observations of the GRB 970616 error box

    DEFF Research Database (Denmark)

    Gorosabel, J.; Castro-Tirado, A.J.; Pedersen, Henrik;

    1999-01-01

    We report on near-infrared and optical observations of the GRB 970616 error box and of the X-ray sources discovered by ASCA and ROSAT in the region. No optical transient was found either within the IPN band or in the X-ray error boxes, similarly to other bursts, and we suggest that either...

  19. FERMI OBSERVATIONS OF HIGH-ENERGY GAMMA-RAY EMISSION FROM GRB 090217A

    International Nuclear Information System (INIS)

    The Fermi observatory is advancing our knowledge of gamma-ray bursts (GRBs) through pioneering observations at high energies, covering more than seven decades in energy with the two on-board detectors, the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM). Here, we report on the observation of the long GRB 090217A which triggered the GBM and has been detected by the LAT with a significance greater than 9σ. We present the GBM and LAT observations and on-ground analyses, including the time-resolved spectra and the study of the temporal profile from 8 keV up to ∼1 GeV. All spectra are well reproduced by a Band model. We compare these observations to the first two LAT-detected, long bursts GRB 080825C and GRB 080916C. These bursts were found to have time-dependent spectra and exhibited a delayed onset of the high-energy emission, which are not observed in the case of GRB 090217A. We discuss some theoretical implications for the high-energy emission of GRBs.

  20. Cosmology with Gamma-Ray Bursts Using k-correction

    Directory of Open Access Journals (Sweden)

    A. Kovács

    2011-01-01

    Full Text Available In the case of Gamma Ray Bursts with measured redshift, we can calculate the k-correction to get the fluence and energy that were actually produced in the comoving system of the GRB. To achieve this we have to use well-fitted parameters of GRB spectrum, available in the GCN database. The output of the calculations is the comoving isotropic energy Eiso, but this is not the endpoint: this data can be useful forestimating the ΩM parameter of the Universe and for making a GRB Hubble diagram usig Amati’s relation.

  1. GRB 090510: a genuine short-GRB from a binary neutron star coalescing into a Kerr-Newman black hole

    CERN Document Server

    Enderli, M; Muccino, M; Aimuratov, Y; Bianco, C L; Cherubini, C; Kovacevic, M; Moradi, R; Penacchioni, A V; Pisani, G B; Rueda, J A; Wang, Y

    2016-01-01

    In a new classification of merging binary neutron stars (NSs) we separate short gamma-ray bursts (GRBs) in two sub-classes. The ones with $E_{\\rm iso}\\lesssim10^{52}$ erg coalesce to form a massive NS and are indicated as short gamma-ray flashes (S-GRFs). The hardest, with $E_{\\rm iso}\\gtrsim10^{52}$ erg, coalesce to form a black hole (BH) and are indicated as genuine short-GRBs (S-GRBs). Within the fireshell model, S-GRBs exhibit three different components: the P-GRB emission, observed at the transparency of a self-accelerating baryon-$e^+e^-$ plasma; the prompt emission, originating from the interaction of the accelerated baryons with the circumburst medium; the high-energy (GeV) emission, observed after the P-GRB and indicating the formation of a BH. GRB 090510 gives the first evidence for the formation of a Kerr-Newman BH. Its P-GRB spectrum can be fitted by a convolution of thermal spectra whose origin can be traced back to an axially symmetric dyadotorus. A large value of the angular momentum of the new...

  2. GRB 090902B: AFTERGLOW OBSERVATIONS AND IMPLICATIONS

    International Nuclear Information System (INIS)

    The optical-infrared afterglow of the Large Area Telescope (LAT)-detected long-duration burst, GRB 090902B, has been observed by several instruments. The earliest detection by ROTSE-IIIa occurred 80 minutes after detection by the Gamma-ray Burst Monitor instrument on board the Fermi Gamma-Ray Space Telescope, revealing a bright afterglow and a decay slope suggestive of a reverse shock origin. Subsequent optical-IR observations followed the light curve for 6.5 days. The temporal and spectral behavior at optical-infrared frequencies is consistent with synchrotron fireball model predictions; the cooling break lies between optical and XRT frequencies ∼1.9 days after the burst. The inferred electron energy index is p = 1.8 ± 0.2, which would however imply an X-ray decay slope flatter than observed. The XRT and LAT data have similar spectral indices and the observed steeper value of the LAT temporal index is marginally consistent with the predicted temporal decay in the radiative regime of the forward shock model. Absence of a jet break during the first 6 days implies a collimation-corrected γ-ray energy Eγ > 2.2 x 1052 erg, one of the highest ever seen in a long-duration gamma-ray bursts. More events combining GeV photon emission with multiwavelength observations will be required to constrain the nature of the central engine powering these energetic explosions and to explore the correlations between energetic quanta and afterglow emission.

  3. EVIDENCE FOR A PHOTOSPHERIC COMPONENT IN THE PROMPT EMISSION OF THE SHORT GRB 120323A AND ITS EFFECTS ON THE GRB HARDNESS-LUMINOSITY RELATION

    International Nuclear Information System (INIS)

    The short GRB 120323A had the highest flux ever detected with the Gamma-Ray Burst Monitor on board the Fermi Gamma-Ray Space Telescope. Here we study its remarkable spectral properties and their evolution using two spectral models: (1) a single emission component scenario, where the spectrum is modeled by the empirical Band function (a broken power law), and (2) a two-component scenario, where thermal (a Planck-like function) emission is observed simultaneously with a non-thermal component (a Band function). We find that the latter model fits the integrated burst spectrum significantly better than the former, and that their respective spectral parameters are dramatically different: when fit with a Band function only, the Epeak of the event is unusually soft for a short gamma-ray burst (GRB; 70 keV compared to an average of 300 keV), while adding a thermal component leads to more typical short GRB values (Epeak ∼ 300 keV). Our time-resolved spectral analysis produces similar results. We argue here that the two-component model is the preferred interpretation for GRB 120323A based on (1) the values and evolution of the Band function parameters of the two component scenario, which are more typical for a short GRB, and (2) the appearance in the data of a significant hardness-intensity correlation, commonly found in GRBs, when we employee two-component model fits; the correlation is non-existent in the Band-only fits. GRB 110721A, a long burst with an intense photospheric emission, exhibits the exact same behavior. We conclude that GRB 120323A has a strong photospheric emission contribution, observed for the first time in a short GRB. Magnetic dissipation models are difficult to reconcile with these results, which instead favor photospheric thermal emission and fast cooling synchrotron radiation from internal shocks. Finally, we derive a possibly universal hardness-luminosity relation in the source frame using a larger set of GRBs (LiBand = (1.59 ± 0.84) x 1050 (Epeak

  4. The circumburst environment of a FRED GRB: study of the prompt emission and X-ray/optical afterglow of GRB 051111

    OpenAIRE

    Guidorzi, C.; Gomboc, A.; Kobayashi, S; Mundell, C. G.; Rol, E.; Bode, M.F.; Carter, D.; La Parola, V.; Melandri, A.; Monfardini, A.; Mottram, C. J.; O'Brien, P.T.; Page, K. L.; Sakamoto, T; Smith, R.J.

    2006-01-01

    We report a multi-wavelength analysis of the prompt emission and early afterglow of GRB051111 and discuss its properties in the context of current fireball models. The detection of GRB051111 by the Burst Alert Telescope on-board Swift triggered early BVRi' observations with the 2-m robotic Faulkes Telescope North in Hawaii, as well as X-ray observations with the Swift X-Ray Telescope. The prompt gamma-ray emission shows a classical FRED profile. The optical afterglow light curves are fitted w...

  5. EVIDENCE FOR A PHOTOSPHERIC COMPONENT IN THE PROMPT EMISSION OF THE SHORT GRB 120323A AND ITS EFFECTS ON THE GRB HARDNESS-LUMINOSITY RELATION

    Energy Technology Data Exchange (ETDEWEB)

    Guiriec, S.; McEnery, J.; Gehrels, N. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Daigne, F.; Hascoeet, R.; Mochkovitch, R. [Institut d' Astrophysique de Paris UMR 7095 Universite Pierre et Marie Curie-Paris 06 (France); CNRS 98 bis bd Arago, F-75014 Paris (France); Vianello, G. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Ryde, F. [Department of Physics, Royal Institute of Technology, AlbaNova, SE-106 91 Stockholm (Sweden); Kouveliotou, C. [Office of Science and Technology, ZP12, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Xiong, S.; Bhat, P. N.; Burgess, J. M. [University of Alabama in Huntsville, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Foley, S.; McGlynn, S. [UCD School of Physics, University College Dublin, Dublin 4 (Ireland); Gruber, D., E-mail: sylvain.guiriec@nasa.gov [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany)

    2013-06-10

    The short GRB 120323A had the highest flux ever detected with the Gamma-Ray Burst Monitor on board the Fermi Gamma-Ray Space Telescope. Here we study its remarkable spectral properties and their evolution using two spectral models: (1) a single emission component scenario, where the spectrum is modeled by the empirical Band function (a broken power law), and (2) a two-component scenario, where thermal (a Planck-like function) emission is observed simultaneously with a non-thermal component (a Band function). We find that the latter model fits the integrated burst spectrum significantly better than the former, and that their respective spectral parameters are dramatically different: when fit with a Band function only, the E{sub peak} of the event is unusually soft for a short gamma-ray burst (GRB; 70 keV compared to an average of 300 keV), while adding a thermal component leads to more typical short GRB values (E{sub peak} {approx} 300 keV). Our time-resolved spectral analysis produces similar results. We argue here that the two-component model is the preferred interpretation for GRB 120323A based on (1) the values and evolution of the Band function parameters of the two component scenario, which are more typical for a short GRB, and (2) the appearance in the data of a significant hardness-intensity correlation, commonly found in GRBs, when we employee two-component model fits; the correlation is non-existent in the Band-only fits. GRB 110721A, a long burst with an intense photospheric emission, exhibits the exact same behavior. We conclude that GRB 120323A has a strong photospheric emission contribution, observed for the first time in a short GRB. Magnetic dissipation models are difficult to reconcile with these results, which instead favor photospheric thermal emission and fast cooling synchrotron radiation from internal shocks. Finally, we derive a possibly universal hardness-luminosity relation in the source frame using a larger set of GRBs (L{sub i}{sup Band

  6. Spectral Lag Evolution among -Ray Burst Pulses

    Indian Academy of Sciences (India)

    Lan-Wei Jia; Yun-Feng Liang; En-Wei Liang

    2014-09-01

    We analyse the spectral lag evolution of -ray burst (GRB) pulses with observations by CGRO/BATSE. No universal spectral lag evolution feature and pulse luminosity-lag relation within a GRB is observed.Our results suggest that the spectral lag would be due to radiation physics and dynamics of a given emission episode, possibly due to the longer lasting emission in a lower energy band, and the spectral lag may not be an intrinsic parameter to discriminate the long and short GRBs.

  7. Gamma-Ray Bursts Subset and Supernova Remnants Low Radio-Frequency Turnover

    Institute of Scientific and Technical Information of China (English)

    LIU Xiang

    2000-01-01

    Durations of gamma-ray bursts (GRB's) are featured by >2s subset and <2s one, with initial corresponding energy ratio being 20:1. It is found that supernova remants(SNR 's) turnover frequencies peak at 100 and 500 MHz. After assuming that GRB's originate from hypernova and making an analysis on the evolution of GRB's, we find that the initial energy of two GRB subsets leads to a different radio-frequency turnover of their remnant spectra, which accords positively with the turnover-frequency ratio of SNR's.

  8. GRB 010921 Discovery of the First HETE Afterglow

    CERN Document Server

    Price, P A; Berger, E; Djorgovski, S G; Frail, D A; Mahabal, A A; Fox, D W; Harrison, F A; Bloom, J S; Yost, S A; Reichart, D E; Henden, A A; Ricker, G R; Van der Spek, R; Hurley, K; Atteia, J L; Kawai, N; Fenimore, E E; Graziani, C

    2003-01-01

    We report the discovery of the optical and radio afterglow of GRB 010921, the first gamma-ray burst afterglow to be found from a localization by the High Energy Transient Explorer (HETE) satellite. We present optical spectroscopy of the host galaxy which we find to be a dusty and apparently normal star-forming galaxy at z = 0.451. The unusually steep optical spectral slope of the afterglow can be explained by heavy extinction, A_V > 0.5 mag, along the line of sight to the GRB. Dust with similar A_V for the the host galaxy as a whole appears to be required by the measurement of a Balmer decrement in the spectrum of the host galaxy. Thanks to the low redshift, continued observations of the afterglow will enable the strongest constraints, to date, on the existence of a possible underlying supernova.

  9. A Small, Rapid Optical-IR Response Gamma-Ray Burst Space Observatory (The NGRG)

    OpenAIRE

    Grossan, Bruce; Kumar, Pawan; Perley, Daniel; Smoot, George F.

    2014-01-01

    Here we propose a new gamma-ray burst (GRB) mission, the Next Generation Rapid-Response GRB Observatory (NGRG). As with Swift, GRBs are initially located with a coded-mask X-ray camera. However, the NGRG has two new features: First, a beam-steering system to begin optical observations within ~ 1 s after location; second, a near-IR (NIR) camera viewing the same sky, for sensitivity to extinguished bursts. These features allow measurement of the rise phase of GRB optical-NIR emission. Thus far,...

  10. A SUPRAMASSIVE MAGNETAR CENTRAL ENGINE FOR GRB 130603B

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Yi-Zhong; Jin, Zhi-Ping; Wei, Da-Ming [Key Laboratory of dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Science, Nanjing 210008 (China); Yu, Yun-Wei [Institute of Astrophysics, Central China Normal University, Wuhan 430079 (China); Xu, Dong [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Wu, Xue-Feng [Chinese Center for Antarctic Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Zhang, Bing, E-mail: yzfan@pmo.ac.cn, E-mail: zhang@physics.unlv.edu [Department of Physics and Astronomy, University of Nevada, Las Vegas, NV 89154 (United States)

    2013-12-20

    We show that the peculiar early optical emission and, in particular, the X-ray afterglow emission of the short-duration burst GRB 130603B can be explained by continuous energy injection into the blastwave from a supramassive magnetar central engine. The observed energetics and temporal/spectral properties of the late infrared bump (i.e., the {sup k}ilonova{sup )} are also found to be consistent with emission from the ejecta launched during a neutron star (NS)-NS merger and powered by a magnetar central engine. The isotropic-equivalent kinetic energies of both the gamma-ray burst (GRB) blastwave and the kilonova are approximately E{sub k} ∼ 10{sup 51} erg, consistent with being powered by a near-isotropic magnetar wind. However, this relatively small value requires that most of the initial rotational energy of the magnetar (∼a few × 10{sup 52} erg) is carried away by gravitational wave radiation. Our results suggest that (1) the progenitor of GRB 130603B was a NS-NS binary system, the merger product of which would have been a supramassive NS that lasted for about ∼1000 s; (2) the equation of state of the nuclear matter should be stiff enough to allow the survival of a long-lived supramassive NS; thus this suggested that the detection of the bright electromagnetic counterparts of gravitational wave triggers without short GRB associations is promising in the upcoming Advanced LIGO/VIRGO era.

  11. Dust Extinction in High-z Galaxies with GRB Afterglow Spectroscopy - The 2175{\\AA} Feature at z=2.45

    CERN Document Server

    Elíasdóttir, Á; Hjorth, J; Ledoux, C; Watson, D; Andersen, A C; Malesani, D; Vreeswijk, P M; Prochaska, J X; Sollerman, J; Jaunsen, A O

    2008-01-01

    We report the clear detection of the 2175A dust absorption feature in the optical afterglow spectrum of the gamma-ray burst (GRB) GRB070802 at a redshift of z=2.45. This is the highest redshift for a detected 2175A dust bump to date, and it is the first clear detection of the 2175A bump in a GRB host galaxy, while several tens of optical afterglow spectra without the bump have been recorded in the past decade. The derived extinction curve gives A_V=0.8-1.5 depending on the assumed intrinsic slope. Of the three local extinction laws, an LMC type extinction gives the best fit to the extinction curve of the host of GRB070802. Besides the 2175A bump we find that the spectrum of GRB070802 is characterized by unusually strong low-ionization metal lines and possibly a high metallicity for a GRB sightline ([Si/H]=-0.46+/-0.38, [Zn/H]=-0.50+/-0.68). In particular, the spectrum of GRB070802 is unique for a GRB spectrum in that it shows clear CI absorption features, leading us to propose a correlation between the presen...

  12. Radiative Regimes in Gamma-Ray Bursts and Afterglows

    CERN Document Server

    Panaitescu, A

    1997-01-01

    We present numerical simulations of Gamma-Ray Bursts arising from external shocks in the impulsive and wind models, including a weak or a strong coupling between electrons and protons plus magnetic fields, and analyze the burst features in each scenario. The dynamics of the ejecta and external medium are followed into the late stages of deceleration, in order to study the hydrodynamics of the remnant and the temporal and spectral evolution of the afterglow. A brief comparison with the optical and radio afterglows of GRB 970228 and GRB 970508 is made.

  13. The Broadband Afterglow of GRB980703

    CERN Document Server

    Frail, D A; Berger, E; Harrison, F A; Sari, R; Kulkarni, S R; Taylor, G B; Bloom, J S; Fox, D W; Moriarty-Schieven, G H; Price, P A

    2003-01-01

    We present radio observations of the afterglow of the bright gamma-ray burst GRB980703 made between one day and one year after the burst. These data are combined with published late-time radio measurements and existing optical, near-infrared (NIR) and X-ray observations to create a comprehensive broadband dataset for modeling the physical parameters of the outflow. While a wind-stratified medium cannot be ruled out statistically, it requires a high fraction of the shock energy in the electrons, and so is not favored on theoretical grounds. Instead, the data are consistent with a fireball model in which the ejecta are collimated and expanding into a constant density medium. The radio data cannot be fit with an isotropic shock but instead require a jet break at ~ 3.5 days, not seen at optical wavelengths due to the presence of a a bright host galaxy. The addition of the full radio dataset constrains the self-absorption frequency, giving an estimate of the circumburst density of n ~ 30 cm^-3, a value which diffe...

  14. A Reverse Shock in GRB 160509A

    CERN Document Server

    Laskar, Tanmoy; Berger, Edo; Fong, Wen-fai; Margutti, Raffaella; Shivvers, Isaac; Williams, Peter K G; Kopac, Drejc; Kobayashi, Shiho; Mundell, Carole; Gomboc, Andreja; Zheng, WeiKang; Menten, Karl M; Graham, Melissa L; Filippenko, Alexei V

    2016-01-01

    We present the second multi-frequency radio detection of a reverse shock in a $\\gamma$-ray burst. By combining our extensive radio observations of the Fermi-LAT GRB 160509A at $z = 1.17$ up to $20$ days after the burst with Swift X-ray observations and ground-based optical and near-infrared data, we show that the afterglow emission comprises distinct reverse shock and forward shock contributions: the reverse shock emission dominates in the radio band at $\\lesssim10~$days, while the forward shock emission dominates in the X-ray, optical, and near-infrared bands. Through multi-wavelength modeling, we determine a circumburst density of $n_0\\approx10^{-3}~$cm$^{-3}$, supporting our previous suggestion that a low-density circumburst environment is conducive to the production of long-lasting reverse shock radiation in the radio band. We infer the presence of a large excess X-ray absorption column, $N_{\\rm H} \\approx 1.5\\times10^{22}~$cm$^{-2}$, and a high rest-frame optical extinction, $A_{\\rm V}\\approx3.4~$mag. We...

  15. GRB010213, optical observations

    Czech Academy of Sciences Publication Activity Database

    Hudec, René; Jelínek, Martin; Tichý, M.; Tichá, J.

    č. 941 (2001), s. 1 R&D Projects: GA AV ČR IAA3003206; GA MŠk ME 002 Institutional research plan: CEZ:AV0Z1003909 Keywords : gamma-ray bursts Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  16. GRB010214, optical observations

    Czech Academy of Sciences Publication Activity Database

    Hudec, René; Jelínek, Martin; Tichý, M.; Tichá, J.

    č. 942 (2001), s. 1 R&D Projects: GA AV ČR IAA3003206; GA MŠk ME 002 Institutional research plan: CEZ:AV0Z1003909 Keywords : gamma-ray bursts Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  17. GRB 010220, optical observations

    Czech Academy of Sciences Publication Activity Database

    Castro-Tirado, A.J.; Castro Cerón, J.; Mateo Sanguino, T. J.; Hudec, René; Soldán, Jan; Páta, P.; Bernas, M.; Berná, J. A.; Corosabel, J.; de la Morena, B.; Torres Riera, J.

    č. 957 (2001), s. 1 R&D Projects: GA AV ČR IAA3003206; GA MŠk ME 002 Institutional research plan: CEZ:AV0Z1003909 Keywords : gamma-ray bursts Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  18. GRB011030, optical observations

    Czech Academy of Sciences Publication Activity Database

    Hudec, René; Polcar, J.; Tichý, M.; Tichá, J.

    č. 1144 (2001), s. 1 R&D Projects: GA AV ČR IAA3003206; GA MŠk ME 002 Institutional research plan: CEZ:AV0Z1003909 Keywords : gamma-ray bursts Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  19. Swift observations of GRB 050904: the most distant cosmic explosion ever observed

    Science.gov (United States)

    Cusumano, G.; Mangano, V.; Chincarini, G.; Panaitescu, A.; Burrows, D. N.; La Parola, V.; Sakamoto, T.; Campana, S.; Mineo, T.; Tagliaferri, G.; Angelini, L.; Barthelmy, S. D.; Beardmore, A. P.; Boyd, P. T.; Cominsky, L. R.; Gronwall, C.; Fenimore, E. E.; Gehrels, N.; Giommi, P.; Goad, M.; Hurley, K.; Immler, S.; Kennea, J. A.; Mason, K. O.; Marshal, F.; Mészáros, P.; Nousek, J. A.; Osborne, J. P.; Palmer, D. M.; Roming, P. W. A.; Wells, A.; White, N. E.; Zhang, B.

    2007-01-01

    Context: Swift discovered the high redshift (z=6.29) GRB 050904 with the Burst Alert Telescope (BAT) and began observing with its narrow field instruments 161 s after the burst onset. This gamma-ray burst is the most distant cosmic explosion ever observed. Because of its high redshift, the X-ray Telescope (XRT) and BAT simultaneous observations provide 4 orders of magnitude of spectral coverage (0.2-150 keV; 1.4-1090 keV in the source rest frame) at a very early source-frame time (22 s). The X-ray emission was monitored by the XRT up to 10 days after the burst. Aims: We present the analysis of BAT and XRT observations of GRB 050904 and a complete description of its high energy phenomenology. Methods: We performed time resolved spectral analysis and light curve modeling. Results: GRB 050904 was a long, multi-peaked, bright GRB with strong variability during its entire evolution. The light curve observed by the XRT is characterized by the presence of a long flaring activity lasting up to 1-2 h after the burst onset in the burst rest frame, with no evidence of a smooth power-law decay following the prompt emission as seen in other GRBs. However, the BAT tail extrapolated to the XRT band joins the XRT early light curve and the overall behavior resembles that of a very long GRB prompt. The spectral energy distribution softens with time, with the photon index decreasing from -1.2 during the BAT observation to -1.9 at the end of the XRT observation. The dips of the late X-ray flares may be consistent with an underlying X-ray emission arising from the forward shock and with the properties of the optical afterglow reported by Tagliaferri et al. (2005b, A&A, 443, L1). Conclusions: . We interpret the BAT and XRT data as a single continuous observation of the prompt emission from a very long GRB. The peculiarities observed in GRB 050904 could be due to its origin within one of the first star-forming regions in the Universe; very low metallicities of the progenitor at these

  20. Happy Birthday Swift: Ultra-long GRB141121A and its broad-band Afterglow

    CERN Document Server

    Cucchiara, A; Corsi, A; Cenko, S B; Perley, D A; Marshall, A Lien F E; Pagani, C; Toy, V L; Capone, J I; Frail, D A; Horesh, A; Modjaz, M; Butler, N R; Littlejohns, O M; Watson, A M; Kutyrev, A S; Lee, W H; Richer, M G; Klein, C R; Fox, O D; Prochaska, J X; Bloom, J S; Troja, E; Ramirez-Ruiz, E; de Diego, J A; Georgiev, L; Gonzalez, J; Roman-Zuniga, C G; Gehrels, N; Moseley, H

    2015-01-01

    We present our extensive observational campaign on the Swift-discovered GRB141121A, al- most ten years after its launch. Our observations covers radio through X-rays, and extends for more than 30 days after discovery. The prompt phase of GRB 141121A lasted 1410 s and, at the derived redshift of z = 1.469, the isotropic energy is E{\\gamma},iso = 8.0x10^52 erg. Due to the long prompt duration, GRB141121A falls into the recently discovered class of UL-GRBs. Peculiar features of this burst are a flat early-time optical light curve and a radio-to-X-ray rebrightening around 3 days after the burst. The latter is followed by a steep optical-to-X-ray decay and a much shallower radio fading. We analyze GRB 141121A in the context of the standard forward-reverse shock (FS,RS) scenario and we disentangle the FS and RS contributions. Finally, we comment on the puzzling early-time (t ~3 d) behavior of GRB 141121A, and suggest that its interpretation may require a two-component jet model. Overall, our analysis confirms that ...

  1. The jet and circumburst stellar wind of GRB 980519

    CERN Document Server

    Jaunsen, A O; Björnsson, G; Andersen, M I; Pedersen, H; Kjernsmo, K; Korhonen, H; Sørensen, P M; Palazzi, E

    2001-01-01

    We present extensive multi-colour (UBVR_CI_C) photometry of the optical afterglow of GRB 980519. Upon discovery, 8.3 hours after the burst, the source was decaying as a power law, (t-t_GRB)^alpha, with a rapid decay rate alpha_1 = - 1.73+-0.04. About 13 hours after the burst a steepening of the light-curve to alpha_2 = -2.22+-0.04 was observed. Within the framework of current afterglow models, we argue that the rapid initial decline, the `break' in the light curve, and the spectral properties of the afterglow are best interpreted as being due to a collimated ultra-relativistic jet of fixed opening angle expanding into an inhomogeneous medium. In this scenario, we find that the circumburst medium has a density structure that goes as r^(-2.05+-0.22). This is characteristic of a preexisting wind expelled from a massive star. A possible physical scenario is that the progenitor star collapsed to form a black hole (i.e., a `collapsar'), producing the observed burst and afterglow. However, the supernova signature ex...

  2. The Third Swift Burst Alert Telescope Gamma-Ray Burst Catalog

    CERN Document Server

    Lien, Amy; Barthelmy, Scott D; Baumgartner, Wayne H; Cannizzo, John K; Chen, Kevin; Collins, Nicholas R; Cummings, Jay R; Gehrels, Neil; Krimm, Hans A; Markwardt, Craig B; Palmer, David M; Stamatikos, Michael; Troja, Eleonora; Ukwatta, T N

    2016-01-01

    To date, the Burst Alert Telescope (BAT) onboard Swift has detected ~ 1000 gamma-ray bursts (GRBs), of which ~ 360 GRBs have redshift measurements, ranging from z = 0.03 to z = 9.38. We present the analyses of the BAT-detected GRBs for the past ~ 11 years up through GRB151027B. We report summaries of both the temporal and spectral analyses of the GRB characteristics using event data (i.e., data for each photon within approximately 250 s before and 950 s after the BAT trigger time), and discuss the instrumental sensitivity and selection effects of GRB detections. We also explore the GRB properties with redshift when possible. The result summaries and data products are available at http://swift.gsfc.nasa.gov/results/batgrbcat/index.html. In addition, we perform searches for GRB emissions before or after the event data using the BAT survey data. We estimate the false detection rate to be only one false detection in this sample. There are 15 ultra-long GRBs (~ 2% of the BAT GRBs) in this search with confirmed emi...

  3. Gamma-Ray Bursts and Cosmology

    Science.gov (United States)

    Norris, Jay P.

    2003-01-01

    The unrivalled, extreme luminosities of gamma-ray bursts (GRBs) make them the favored beacons for sampling the high redshift Universe. To employ GRBs to study the cosmic terrain -- e.g., star and galaxy formation history -- GRB luminosities must be calibrated, and the luminosity function versus redshift must be measured or inferred. Several nascent relationships between gamma-ray temporal or spectral indicators and luminosity or total energy have been reported. These measures promise to further our understanding of GRBs once the connections between the luminosity indicators and GRB jets and emission mechanisms are better elucidated. The current distribution of 33 redshifts determined from host galaxies and afterglows peaks near z $\\sim$ 1, whereas for the full BATSE sample of long bursts, the lag-luminosity relation predicts a broad peak z $\\sim$ 1--4 with a tail to z $\\sim$ 20, in rough agreement with theoretical models based on star formation considerations. For some GRB subclasses and apparently related phenomena -- short bursts, long-lag bursts, and X-ray flashes -- the present information on their redshift distributions is sparse or entirely lacking, and progress is expected in Swift era when prompt alerts become numerous.

  4. Fermi Observations of High-Energy Gamma-Ray Emission from GRB 080916C

    International Nuclear Information System (INIS)

    Gamma-ray bursts (GRBs) are highly energetic explosions signaling the death of massive stars in distant galaxies. The Gamma-ray Burst Monitor and Large Area Telescope onboard the Fermi Observatory together record GRBs over a broad energy range spanning about 7 decades of gamma-ray energy. In September 2008, Fermi observed the exceptionally luminous GRB 080916C, with the largest apparent energy release yet measured. The high-energy gamma rays are observed to start later and persist longer than the lower energy photons. A simple spectral form fits the entire GRB spectrum, providing strong constraints on emission models. The known distance of the burst enables placing lower limits on the bulk Lorentz factor of the outflow and on the quantum gravity mass. (authors)

  5. Fermi Observations of high-energy gamma-ray emissions from GRB 080916C

    CERN Document Server

    Abdo, A A; Arimoto, M; Asano, K; Atwood, W B; Axelsson, M; Baldini, L; Ballet, J; Band, D L; Barbiellini, Guido; Baring, Matthew G; Bastieri, Denis; Battelino, M; Baughman, B M; Bechtol, K; Bellardi, F; Bellazzini, R; Berenji, B; Bhat, P N; Bissaldi, E; Blandford, R D; Bloom, Elliott D; Bogaert, G; Bogart, J R; Bonamente, E; Bonnell, J; Borgland, A W; Bouvier, A; Bregeon, J; Brez, A; Briggs, M S; Brigida, M; Bruel, P; Burnett, Thompson H; Burrows, David N; Busetto, Giovanni; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Ceccanti, M; Cecchi, C; Celotti, Annalisa; Charles, E; Chekhtman, A; Cheung, C.C.Teddy; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, Johann; Cominsky, Lynn R; Connaughton, V; Conrad, J; Costamante, L; Cutini, S; DeKlotz, M; Dermer, C D; De Angelis, Alessandro; de Palma, F; Digel, S W; Dingus, B L; do Couto e Silva, Eduardo; Drell, P S; Dubois, R; Dumora, D; Edmonds, Y; Evans, P A; Fabiani, D; Farnier, C; Favuzzi, C; Finke, Justin D; Fishman, G; Focke, W B; Frailis, M; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giebels, B; Giglietto, N; Giommi, P; Giordano, F; Glanzman, Thomas Lynn; Godfrey, Gary L; Goldstein, A; Granot, J; Greiner, J; Grenier, I A; Grondin, M H; Grove, J.Eric; Guillemot, L; Guiriec, S; Haller, G; Hanabata, Y; Harding, Alice K; Hayashida, M; Hays, Elizabeth A; Hernando Morata, J A; Hoover, A; Hughes, R E; Johannesson, G; Johnson, A S; Johnson, R P; Johnson, T J; Johnson, W N; Kamae, Tsuneyoshi; Katagiri, H; Kataoka, J; Kavelaars, A; Kawai, N; Kelly, H; Kennea, J; Kerr, M; Kippen, R M; Knodlseder, J; Kocevski, D; Kocian, M L; Komin, N; Kouveliotou, C; Kuehn, Frederick Gabriel Ivar; Kuss, Michael; Lande, J; Landriu, D; Larsson, S; Latronico, L; Lavalley, C; Lee, B; Lee, S H; Lemoine-Goumard, M; Lichti, G G; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, Pasquale; Madejski, G M; Makeev, A; Marangelli, B; Mazziotta, M N; McBreen, Sheila; McEnery, J E; McGlynn, S; Meegan, C; Miszaros, P; Meurer, C; Michelson, P F; Minuti, M; Mirizzi, N; Mitthumsiri, W; Mizuno, T; Moiseev, A A; Monte, C; Monzani, M E; Moretti, E; Morselli, A; Moskalenko, Igor Vladimirovich; Murgia, Simona; Nakamori, T; Nelson, D; Nolan, P L; Norris, J P; Nuss, E; Ohno, M; Ohsugi, Takashi; Okumura, Akira; Omodei, N; Orlando, E; Ormes, J F; Ozaki, M; Paciesas, W S; Paneque, D; Panetta, J H; Parent, D; Pelassa, V; Pepe, M; Perri, M; Pesce-Rollins, M; Petrosian, Vahe; Pinchera, M; Piron, F; Porter, Troy A; Preece, R; Rainr, S; Ramirez-Ruiz, E; Rando, R; Rapposelli, E; Razzano, M; Razzaque, Soebur; Rea, N; Reimer, A; Reimer, O; Reposeur, Thierry; Reyes, Luis C; Ritz, S; Rochester, L S; Rodriguez, A Y; Roth, M; Ryde, F; Sadrozinski, H F W; Sanchez, D; Sander, A; Parkinson, P.M.Saz; Scargle, J D; Schalk, T L; Segal, K N; Sgro, C; Shimokawabe, T; Siskind, E J; Smith, D A; Smith, P D; Spandre, G; Spinelli, P; Stamatikos, M; Starck, Jean-Luc; Stecker, Floyd William; Steinle, H; Stephens, T E; Strickman, M S; Suson, Daniel J; Tagliaferri, G.; Tajima, Hiroyasu; Takahashi, H; Takahashi, T; Tanaka, T; Tenze, A; Thayer, J B; Thayer, J G; Thompson, D J; Tibaldo, L; Torres, Diego F; Tosti, G; Tramacere, A; Turri, M; Tuvi, S; Usher, T L; van der Horst, A J; Vigiani, L; Vilchez, N; Vitale, V; von Kienlin, A; Waite, A P; Williams, D A; Wilson-Hodge, C; Winer, B L; Wood, K S; Wu, X F; Yamazaki, R; Ylinen, T; Ziegler, M

    2009-01-01

    Gamma-ray bursts (GRBs) are highly energetic explosions signaling the death of massive stars in distant galaxies. The Gamma-ray Burst Monitor and Large Area Telescope onboard the Fermi Observatory together record GRBs over a broad energy range spanning about 7 decades of gammaray energy. In September 2008, Fermi observed the exceptionally luminous GRB 080916C, with the largest apparent energy release yet measured. The high-energy gamma rays are observed to start later and persist longer than the lower energy photons. A simple spectral form fits the entire GRB spectrum, providing strong constraints on emission models. The known distance of the burst enables placing lower limits on the bulk Lorentz factor of the outflow and on the quantum gravity mass.

  6. Modeling the early afterglow in the short and hard GRB 090510

    CERN Document Server

    Fraija, Nissim; Veres, Peter; Duran, Rodolfo Barniol

    2016-01-01

    The bright, short and hard GRB 090510 was detected by all instruments aboard Fermi and Swift satellites. The multiwavelength observations of this burst presented similar features with the Fermi-LAT-detected gamma-ray bursts. In the framework of the external shock model of early afterglow, a leptonic scenario that evolves in a homogeneous medium is proposed to revisit GRB 090510 and explain the multiwavelength light curve observations presented in this burst. These observations are consistent with the evolution of a jet before and after the jet break. The long-lasting LAT, X-ray and optical fluxes are explained in the synchrotron emission from the adiabatic forward shock. Synchrotron self-Compton emission from the reverse shock is consistent with the bright LAT peak provided that progenitor environment is entrained with strong magnetic fields. It could provide compelling evidence of magnetic field amplification in the neutron star merger.

  7. Critical Test Of Gamma Ray Burst Theories

    CERN Document Server

    Dado, Shlomo

    2016-01-01

    Long and precise follow-up measurements of the X-ray afterglow (AG) of very intense gamma ray bursts (GRBs) provide a critical test of GRB afterglow theories. Here we show that the power-law decline with time of X-ray AG of GRB 130427A, the longest measured X-ray AG of an intense GRB with the Swift, Chandra and XMM Newton satellites, and of all other well measured late-time X-ray afterglow of intense GRBs, is that predicted by the cannonball (CB) model of GRBs from their measured spectral index, while it disagrees with that predicted by the widely accepted fireball (FB) models of GRBs.

  8. VLT/X-shooter spectroscopy of the GRB 120327A afterglow

    CERN Document Server

    D'Elia, V; Goldoni, P; Covino, S; Postigo, A de Ugarte; Ledoux, C; Calura, F; Gorosabel, J; Malesani, D; Sanchez-Ramirez, F Matteucci R; Savaglio, S; Castro-Tirado, A J; Hartoog, O E; Kaper, L; Munoz-Darias, T; Pian, E; Piranomonte, S; Tagliaferri, G; Tanvir, N; Vergani, S D; Watson, D J; Xu, D

    2014-01-01

    We present a study of the environment of the Swift long gamma-ray burst GRB 120327A at z ~2.8 through optical spectroscopy of its afterglow. We analyzed medium-resolution, multi-epoch spectroscopic observations (~7000 - 12000, corresponding to ~ 15 - 23 km/s, S/N = 15- 30 and wavelength range 3000-25000AA) of the optical afterglow of GRB 120327A, taken with X-shooter at the VLT 2.13 and 27.65 hr after the GRB trigger. The first epoch spectrum shows that the ISM in the GRB host galaxy at z = 2.8145 is extremely rich in absorption features, with three components contributing to the line profiles. The hydrogen column density associated with GRB 120327A has log NH / cm^(-2) = 22.01 +/- 0.09, and the metallicity of the host galaxy is in the range [X/H] = -1.3 to -1.1. In addition to the ground state lines, we detect absorption features associated with excited states of CII, OI, SiII, FeII, and NiII, which we used to derive information on the distance between the host absorbing gas and the site of the GRB explosion...

  9. Revisiting the dispersion measure of fast radio bursts associated with gamma-ray burst afterglows

    International Nuclear Information System (INIS)

    Some fast radio bursts (FRBs) are expected to be associated with the afterglow emission of gamma-ray bursts (GRBs), while a short-lived, supermassive neutron star (NS) forms during the GRBs. I investigate the possible contributions to the dispersion measure (DM) of the FRBs from the GRB ejecta and the wind blown from the precollapsing NS. On the one hand, sometimes an internal X-ray plateau afterglow could be produced by the NS wind, which indicates that a great number of electron-positron pairs are carried by the wind. If the pair-generation radius satisfies a somewhat rigorous condition, the relativistic and dense wind would contribute a high DM to the associated FRB, which can be comparable to and even exceed the DM contributed by the intergalactic medium. On the other hand, if the wind only carries a Goldreich-Julian particle flux, its DM contribution would become negligible; meanwhile, the internal plateau afterglow would not appear. Alternatively, the FRB should be associated with a GRB afterglow produced by the GRB external shock, i.e., an energy-injection-caused shallow-decay afterglow or a normal single-power-law afterglow if the impulsive energy release of the GRB is high enough. In the latter case, the DM contributed by the high-mass GRB ejecta could be substantially important, in particular, for an environment of main-sequence stellar wind. In summary, a careful assessment on the various DM contributors could be required for the cosmological application of the expected FRB-GRB association. The future DM measurements of GRB-associated FRBs could provide a constraint on the physics of NS winds.

  10. GRB 080517: A local, low luminosity GRB in a dusty galaxy at z=0.09

    CERN Document Server

    Stanway, E R; Tanvir, N R; Wiersema, K; van der Horst, A; Mundell, C G; Guidorzi, C

    2014-01-01

    We present an analysis of the photometry and spectroscopy of the host galaxy of Swift-detected GRB 080517. From our optical spectroscopy, we identify a redshift of z = 0.089 +/- 0.003, based on strong emission lines, making this a rare example of a very local, low luminosity, long gamma ray burst. The galaxy is detected in the radio with a flux density of S(4.8GHz) =0.22 +/- 0.04mJy - one of relatively few known GRB hosts with a securely measured radio flux. Both optical emission lines and a strong detection at 22 um suggest that the host galaxy is forming stars rapidly, with an inferred star formation rate ~16 Msun/yr and a high dust obscuration (E(B-V )>1, based on sight-lines to the nebular emission regions). The presence of a companion galaxy within a projected distance of 25 kpc, and almost identical in redshift, suggests that star formation may have been triggered by galaxy-galaxy interaction. However, fitting of the remarkably flat spectral energy distribution from the ultraviolet through to the infrar...

  11. Evidence for jet launching close to the black hole in GRB 101219B - a Fermi GRB dominated by thermal emission

    CERN Document Server

    Larsson, J; Burgess, J M

    2015-01-01

    We present observations by the Fermi Gamma-Ray Space Telescope Gamma-Ray Burst Monitor (GBM) of the nearby (z=0.55) GRB 101219B. This burst is a long GRB, with an associated supernova and with a blackbody component detected in the early afterglow observed by the Swift X-ray Telescope (XRT). Here we show that the prompt gamma-ray emission has a blackbody spectrum, making this the second such burst observed by Fermi GBM. The properties of the blackbody, together with the redshift and our estimate of the radiative efficiency, makes it possible to calculate the absolute values of the properties of the outflow. We obtain an initial Lorentz factor Gamma=138\\pm 8, a photospheric radius r_phot=4.4\\pm 1.9 \\times 10^{11} cm and a launch radius r_0=2.7\\pm 1.6 \\times 10^{7} cm. The latter value is close to the event horizon for a stellar-mass black hole and suggests that the jet has a relatively unobstructed path through the star. There is no smooth connection between the blackbody components seen by GBM and XRT, ruling ...

  12. BurstCube: A Gamma-ray Burst Detecting Swarm of CubeSats

    Science.gov (United States)

    Perkins, Jeremy S; Racusin, Judith L.; Krizmanic, John F; McEnery, Julie E.

    2014-08-01

    The study of gamma-ray bursts (GRBs) has seen major advances in the past decade based on the results of several highly successful missions like Swift and Fermi. These prolific GRB detectors have enabled multi-wavelength follow-up of hundreds of GRBs and have allowed us to answer some of the outstanding questions in this field as well as prompted research in many new directions. It is critical to continue GRB detection, especially with gravitational wave detectors coming online in the next few years, e.g. advanced LIGO/Virgo, and the continued operation of multi-messenger observatories such as IceCube. Without the detection and study of counterparts to these future non-photon detections, the full characterization of a GRB would be difficult. The current GRB detection technology is at a mature level such that small, inexpensive detectors on CubeSats could perform as well or better than the current generation of GRB scintillator detectors. This paper will detail the design parameters and performance of small, GRB detecting CubeSats operating in a swarm that can detect, localize, and characterize GRBs via the high energy photon signatures.

  13. SPECTROSCOPIC EVIDENCE FOR SN 2010ma ASSOCIATED WITH GRB 101219B

    International Nuclear Information System (INIS)

    We report on the spectroscopic detection of supernova SN 2010ma associated with the long gamma-ray burst GRB 101219B. We observed the optical counterpart of the GRB on three nights with the X-shooter spectrograph at the Very Large Telescope. From weak absorption lines, we measure a redshift of z = 0.55. The first-epoch UV-near-infrared afterglow spectrum, taken 11.6 hr after the burst, is well fit by a power law consistent with the slope of the X-ray spectrum. The second- and third-epoch spectra (obtained 16.4 and 36.7 days after the burst), however, display clear bumps closely resembling those of the broad-lined type-Ic SN 1998bw if placed at z = 0.55. Apart from demonstrating that spectroscopic SN signatures can be observed for GRBs at these large distances, our discovery makes a step forward in establishing a general connection between GRBs and SNe. In fact, unlike most previous unambiguous GRB-associated SNe, GRB 101219B has a large gamma-ray energy (Eiso = 4.2 x 1051 erg), a bright afterglow, and obeys the 'Amati' relation, thus being fully consistent with the cosmological population of GRBs.

  14. Spectroscopic evidence for SN 2010ma associated with GRB 101219B

    CERN Document Server

    Sparre, M; Fynbo, J P U; Malesani, D; Goldoni, P; Postigo, A de Ugarte; Covino, S; D'Elia, V; Flores, H; Hammer, F; Hjorth, J; Jakobsson, P; Kaper, L; Leloudas, G; Levan, A J; Milvang-Jensen, B; Schulze, S; Tagliaferri, G; Tanvir, N R; Watson, D J; Wiersema, K; Wijers, R A M J

    2011-01-01

    We report on the spectroscopic detection of supernova SN 2010ma associated with the long gamma-ray burst GRB 101219B. We observed the optical counterpart of the GRB on three nights with the X-shooter spectrograph at the VLT. From weak absorption lines, we measure a redshift of z=0.55. The first epoch UV--near-infrared afterglow spectrum, taken 11.6 hr after the burst, is well fit by a power law consistent with the slope of the X-ray spectrum. The second and third epoch spectra (obtained 16.4 and 36.7 days after the burst), however, display clear bumps closely resembling those of the broad-lined type-Ic SN 1998bw if placed at z=0.55. Apart from demonstrating that spectroscopic SN signatures can be observed for GRBs at these large distances, our discovery makes a step forward in establishing a general connection between GRBs and SNe. In fact, unlike most previous unambiguous GRB-associated SNe, GRB 101219B has a large gamma-ray energy ($E_{\\rm iso}= 4.2 \\times 10^{51}$ erg), a bright afterglow, and obeys the "A...

  15. Probing the bright radio flare and afterglow of GRB 130427A with the Arcminute Microkelvin Imager

    Science.gov (United States)

    Anderson, G. E.; van der Horst, A. J.; Staley, T. D.; Fender, R. P.; Wijers, R. A. M. J.; Scaife, A. M. M.; Rumsey, C.; Titterington, D. J.; Rowlinson, A.; Saunders, R. D. E.

    2014-05-01

    We present one of the best sampled early-time light curves of a gamma-ray burst (GRB) at radio wavelengths. Using the Arcminute Mircrokelvin Imager (AMI), we observed GRB 130427A at the central frequency of 15.7 GHz between 0.36 and 59.32 d post-burst. These results yield one of the earliest radio detections of a GRB and demonstrate a clear rise in flux less than one day after the γ-ray trigger followed by a rapid decline. This early-time radio emission probably originates in the GRB reverse shock so our AMI light curve reveals the first ever confirmed detection of a reverse shock peak in the radio domain. At later times (about 3.2 d post-burst), the rate of decline decreases, indicating that the forward shock component has begun to dominate the light curve. Comparisons of the AMI light curve with modelling conducted by Perley et al. show that the most likely explanation of the early-time 15.7 GHz peak is caused by the self-absorption turn-over frequency, rather than the peak frequency, of the reverse shock moving through the observing bands.

  16. The LAGO Collaboration: Searching for high energy GRB emissions in Latin America

    Science.gov (United States)

    Barros, H.; Lago Collaboration

    2012-02-01

    During more than a decade Gamma Ray Bursts (GRB a cosmological phenomena of tremendous power) have been extensively studied in the keV - MeV energy range. However, the higher energy emission still remains a mystery. The Large Aperture GRB Observatory (L.A.G.O.) is an international collaboration started in 2005 aiming at a better understanding of the GRB by studying their emission at high energies (> 1 GeV), where the fluxes are low and measurements by satellites are difficult. This is done using the Single Particle Technique, by means of ground-based Water Cherenkov Detectors (WCD) at sites of high altitude. At those altitudes it is possible to detect air showers produced by high energy photons from the GRB, i. e. a higher rate of events on a short time scale, of the order of the second. The Pierre Auger Observatory could detect such GRB given its large number of detectors, but at 1400 m.a.s.l. the expected signal is quite small. At higher altitudes, similar performance is expected with only a very small number of WCD. As of 2011, high altitude WCD are in operation at Sierra Negra (Mexico, 4650 m.a.s.l.), Chacaltaya (Bolivia, 5200 m.a.s.l.), Maracapomacocha (Peru, 4200 m.a.s.l.), and new WCDs are being installed in Venezuela (Pico Espejo, 4750 m.a.s.l.), Argentina, Brazil, Chile, Colombia and Guatemala. Most of the new WCDs will not be at high enough altitude to detect GRB, never the less it will allow obtaining valuable measurements of secondaries at ground level, which are relevant for solar physics. The LAGO sensitivity to GRB is determined from simulations (under a sudden increase of 1 GeV - 1 TeV photons from a GRB) of the gamma initiated particle shower in the atmosphere and the WCD response to secondaries. We report on WDC calibration and operation at high altitude, GRB detectability, background rates, search for bursts in several months of preliminary data, as well as search for signals at ground level when satellite burst is reported, all these show the

  17. GRB 050822: Detailed analysis of an XRF observed by Swift

    OpenAIRE

    Godet, O; Page, K. L.; Osborne, J.; B. Zhang; Burrows, D.N.; O'Brien, P. T.; Hill, J. E.; Racusin, J.; Beardmore, A. P.; Goad, M. R.; Falcone, A; Morris, D. C.; Ziaeepour, H.

    2007-01-01

    We report on the temporal and spectral characteristics of the early X-ray emission from the GRB 050822 as observed by Swift. This burst is likely to be an XRF showing major X-ray flares in its XRT light-curve. The quality of the data allows a detailed spectral analysis of the early afterglow in the X-ray band. During the X-ray flares, a positive correlation between the count rate and the spectral hardness (i.e. the higher the count rate, the harder the spectrum) is clearly seen for the X-ray ...

  18. Preliminary Results on VLT K-band Imaging Observations of GRB Host Galaxies

    Indian Academy of Sciences (India)

    E. Le Floc’h; I. F. Mirabel; P.-A. Duc

    2002-03-01

    We have obtained -band imaging observations of Gamma-Ray Burst (GRB) host galaxies with the near-infrared spectro-imager ISAAC installed on the Very Large Telescope at Paranal (Chile). The derived magnitudes, combined with other photometric data taken from the literature, are used to investigate the – colors of GRB hosts. We do not find any extremely reddened starbursts in our sample, despite the capability of GRBs to trace star formation even in dusty regions. The observed – colors are on the contrary typical of irregular and spiral blue galaxies at high redshift.

  19. Flux upper limit of gamma-ray emission by GRB050713a from MAGIC Telescope observations

    CERN Document Server

    Albert, J; Anderhub, H; Antoranz, P; Armada, A; Asensio, M; Baixeras, C; Barrio, J A; Bartelt, M; Bartko, H; Bastieri, D; Bavikadi, R; Bednarek, W; Berger, K; Bigongiari, C; Biland, A; Bisesi, E; Böck, R K; Bretz, T; Britvitch, I; Camara, M; Chilingarian, A A; Ciprini, S; Coarasa, J A; Commichau, S C; Contreras, J L; Cortina, J; Curtef, V; Danielyan, V; Dazzi, F; De Angelis, A; De Reyes, R; De Lotto, B; Domingo-Santamaria, E; Dorner, D; Doro, M; Errando, M; Fagiolini, M; Ferenc, D; Fernández, E; Firpo, R; Flix, J; Fonseca, M V; Font, L; Galante, N; Garczarczyk, M; Gaug, M; Giller, M; Göbel, F; Hakobyan, D; Hayashida, M; Hengstebeck, T; Höhne, D; Hose, J; Jacon, P; Kalekin, O; Kranich, D; Laille, A; Lenisa, T; Liebing, P; Lindfors, E; Longo, F; López, J; López, M; Lorenz, E; Lucarelli, F; Majumdar, P; Maneva, G; Mannheim, K; Mariotti, M; Martínez, M; Mase, K; Mazin, D; Meucci, M; Meyer, M; Miranda, J M; Mirzoyan, R; Mizobuchi, S; Moralejo, A; Nilsson, K; Oña-Wilhelmi, E; Orduna, R; Otte, N; Oya, I; Paneque, D; Paoletti, R; Pasanen, M; Pascoli, D; Pauss, F; Pavel, N; Pegna, R; Persic, M; Peruzzo, L; Piccioli, A; Prandini, E; Rico, J; Rhode, W; Riegel, B; Rissi, M; Robert, A

    2006-01-01

    The long-duration GRB050713a was observed by the MAGIC Telescope, 40 seconds after the burst onset, and followed up for 37 minutes, until twilight. The observation, triggered by a SWIFT alert, covered energies above ~175 GeV. Using standard MAGIC analysis, no evidence for a gamma signal was found. As the redshift of the GRB was not measured directly, the flux upper limit, estimated by MAGIC, is still compatible with the assumption of an unbroken power-law spectrum extending from a few hundred keV to our energy range.

  20. Investigation of Primordial Black Hole Bursts Using Interplanetary Network Gamma-ray Bursts

    Science.gov (United States)

    Ukwatta, T. N.; Hurley, K.; MacGibbon, J. H.; Svinkin, D. S.; Aptekar, R. L.; Golenetskii, S. V.; Frederiks, D. D.; Pal'shin, V. D.; Goldsten, J.; Boynton, W.; Kozyrev, A. S.; Rau, A.; von Kienlin, A.; Zhang, X.; Connaughton, V.; Yamaoka, K.; Ohno, M.; Ohmori, N.; Feroci, M.; Frontera, F.; Guidorzi, C.; Cline, T.; Gehrels, N.; Krimm, H. A.; McTiernan, J.

    2016-07-01

    The detection of a gamma-ray burst (GRB) in the solar neighborhood would have very important implications for GRB phenomenology. The leading theories for cosmological GRBs would not be able to explain such events. The final bursts of evaporating primordial black holes (PBHs), however, would be a natural explanation for local GRBs. We present a novel technique that can constrain the distance to GRBs using detections from widely separated, non-imaging spacecraft. This method can determine the actual distance to the burst if it is local. We applied this method to constrain distances to a sample of 36 short-duration GRBs detected by the Interplanetary Network (IPN) that show observational properties that are expected from PBH evaporations. These bursts have minimum possible distances in the 1013–1018 cm (7–105 au) range, which are consistent with the expected PBH energetics and with a possible origin in the solar neighborhood, although none of the bursts can be unambiguously demonstrated to be local. Assuming that these bursts are real PBH events, we estimate lower limits on the PBH burst evaporation rate in the solar neighborhood.

  1. GRB physics with Fermi

    CERN Document Server

    Medvedev, Mikhail V

    2009-01-01

    Radiation from GRBs in the prompt phase, flares and an afterglow is thought to be produced by accelerated electrons in magnetic fields. Such emission may be produced at collisionless shocks of baryonic outflows or at reconnection sites (at least for the prompt and flares) of the magnetically dominated (Poynting flux driven) outflows, where no shocks presumably form at all. An astonishing recent discovery is that during reconnection strong small-scale magnetic fields are produced via the Weibel instability, very much like they are produced at relativistic shocks. The relevant physics has been successfully and extensively studied with the PIC simulations in 2D and, to some extent, in 3D for the past few years. We discuss how these simulations predict the existence of MeV-range synchrotron/jitter emission in some GRBs, which can be observed with Fermi. Recent results on modeling of the spectral variability and spectral correlations of the GRB prompt emission in the Weibel-jitter paradigm applicable to both baryo...

  2. REM observations of GRB060418 and GRB060607A: the onset of the afterglow and the initial fireball Lorentz factor determination

    International Nuclear Information System (INIS)

    Context. Gamma-ray burst (GRB) emission is believed to originate in highly relativistic fireballs. Aims. Currently, only lower limits were securely set to the initial fireball Lorentz factor Γ0. We aim to provide a direct measure of Γ0. Methods. The early-time afterglow light curve carries information about Γ0, which determines the time of the afterglow peak. We have obtained early observations of the near-infrared afterglows of GRB060418 and GRB060607A with the REM robotic telescope. Results. For both events, the afterglow peak could be clearly singled out, allowing a firm determination of the fireball Lorentz of Γ0 similar to 400, fully confirming the highly relativistic nature of GRB fireballs. The deceleration radius was inferred to be R-dec approximate to 1017 cm. This is much larger than the internal shocks radius (believed to power the prompt emission), thus providing further evidence for a different origin of the prompt and afterglow stages of the GRB. (authors)

  3. REM observations of GRB060418 and GRB060607A: the onset of the afterglow and the initial fireball Lorentz factor determination

    Energy Technology Data Exchange (ETDEWEB)

    Molinari, E.; Covino, S.; D' Avanzo, P.; Chincarini, G.; Zerbi, F.M.; Conconi, P.; Malaspina, G.; Campana, S.; Rizzuto, D.; Tagliaferri, G. [Osserv Astron Brera, INAF, I-23807 Merate, LC, (Italy); Vergani, S.D.; Meurs, E.J.A.; Ward, P.A. [DIAS, Dunsink Observ, Dublin 15, (Ireland); Vergani, S.D.; Norci, L. [Dublin City Univ, Sch Phys Sci, NCPST, Dublin 9, (Ireland); Malesani, D. [SISSA, ISAS, I-34014 Trieste, (Italy); Malesani, D. [Univ Copenhagen, Niels Bohr Inst, Dark Cosmol Ctr, DK-2100 Copenhagen, (Denmark); D' Avanzo, P. [Univ Insubria, Dipartimento Matemat and Fis, I-22100 Como, (Italy); Chincarini, G.; Rizzuto, D. [Univ Milan, I-20126 Milan, (Italy); Antonelli, L.A.; Testa, V.; Vitali, F.; D' Alessio, F.; Guetta, D.; Piranomonte, S.; Stella, L. [Osserv Astron Roma, INAF, I-00040 Monte Porzio Catone, (Italy); Tosti, G. [Univ Perugia, Dipartimento Fis, Osservatorio Astron, I-06123 Perugia, (Italy); Nicastro, L.; Palazzi, E.; Masetti, N. [IASF Bologna, INAF, I-40129 Bologna, (Italy); Goldoni, P. [APC, Lab Astroparticule and Cosmol, UMR 7164, F-75231 Paris 05, (France); Goldoni, P. [CEA Saclay, DSM, DAPNIA, Serv Astrophys, F-91191 Gif Sur Yvette, (France)] (and others)

    2007-07-01

    Context. Gamma-ray burst (GRB) emission is believed to originate in highly relativistic fireballs. Aims. Currently, only lower limits were securely set to the initial fireball Lorentz factor {gamma}{sub 0}. We aim to provide a direct measure of {gamma}{sub 0}. Methods. The early-time afterglow light curve carries information about {gamma}{sub 0}, which determines the time of the afterglow peak. We have obtained early observations of the near-infrared afterglows of GRB060418 and GRB060607A with the REM robotic telescope. Results. For both events, the afterglow peak could be clearly singled out, allowing a firm determination of the fireball Lorentz of {gamma}{sub 0} similar to 400, fully confirming the highly relativistic nature of GRB fireballs. The deceleration radius was inferred to be R-dec approximate to 10{sup 17} cm. This is much larger than the internal shocks radius (believed to power the prompt emission), thus providing further evidence for a different origin of the prompt and afterglow stages of the GRB. (authors)

  4. WATCH observations of gamma ray bursts during 1990–1992

    DEFF Research Database (Denmark)

    Castro-Tirado, A.; Brandt, Søren; Lund, Niels; Lapshov, I. Y.; Terekhov, O.; Sunyaev, R. A.

    The first WATCH/GRANAT Gamma‐Ray Burst Catalogue comprises 70 events which have been detected by WATCH during the period December 1989–September 1992. 32 GRBs could be localized within a 3σ error radii of 1°. We have found a weak (2.2σ) clustering of these 32 bursts towards the Galactic Center....... However we conclude that there is no strong evidence of concentration of the bursts towards the Galactic Center or Plane. Around ∼10% of the 70 bursts showed x‐ray precursor or/and X‐ray tail. We discuss the possibility that two events, GRB 900126 and GRB 920311, would have been produced by the same...

  5. WATCH observations of gamma ray bursts during 1990–1992

    DEFF Research Database (Denmark)

    Castro-Tirado, A.; Brandt, Søren; Lund, Niels;

    1994-01-01

    . However we conclude that there is no strong evidence of concentration of the bursts towards the Galactic Center or Plane. Around ∼10% of the 70 bursts showed x‐ray precursor or/and X‐ray tail. We discuss the possibility that two events, GRB 900126 and GRB 920311, would have been produced by the same......The first WATCH/GRANAT Gamma‐Ray Burst Catalogue comprises 70 events which have been detected by WATCH during the period December 1989–September 1992. 32 GRBs could be localized within a 3σ error radii of 1°. We have found a weak (2.2σ) clustering of these 32 bursts towards the Galactic Center...

  6. The Supernova -- Gamma-Ray Burst Connection

    CERN Document Server

    Woosley, S E

    2006-01-01

    Observations show that at least some gamma-ray bursts (GRBs) happen simultaneously with core-collapse supernovae (SNe), thus linking by a common thread nature's two grandest explosions. We review here the growing evidence for and theoretical implications of this association, and conclude that most long-duration soft-spectrum GRBs are accompanied by massive stellar explosions (GRB-SNe). The kinetic energy and luminosity of well-studied GRB-SNe appear to be greater than those of ordinary SNe, but evidence exists, even in a limited sample, for considerable diversity. The existing sample also suggests that most of the energy in the explosion is contained in nonrelativistic ejecta (producing the supernova) rather than in the relativistic jets responsible for making the burst and its afterglow. Neither all SNe, nor even all SNe of Type Ibc produce GRBs. The degree of differential rotation in the collapsing iron core of massive stars when they die may be what makes the difference.

  7. Gravitational Waves versus X and Gamma Ray Emission in a Short Gamma-Ray Burst

    OpenAIRE

    Oliveira, F. G.; Rueda, Jorge A.; Ruffini, Remo

    2012-01-01

    The recent progress in the understanding the physical nature of neutron star equilibrium configurations and the first observational evidence of a genuinely short gamma-ray burst, GRB 090227B, allows to give an estimate of the gravitational waves versus the X and Gamma-ray emission in a short gamma-ray burst.

  8. Pulse-wise GRB correlation: implication as a cosmological tool

    CERN Document Server

    Basak, Rupal

    2016-01-01

    Gamma-ray bursts (GRBs) are cosmological explosions which carry valuable information from the distant past of the expanding universe. One of the greatest discoveries in modern cosmology is the finding of the accelerated expansion of the universe using Type Ia supernovae (SN Ia) as standard candles. However, due to the interstellar extinction SN Ia can be seen only up to a redshift $z\\sim 1.5$. GRBs are considered as the potential alternative to push this limit to as high as $z\\sim 10$, a redshift regime corresponding to an epoch when the universe just started to form the first structures. There exist several correlations between the energy and an observable of a GRB which can be used to derive luminosity distance. In recent works, we have studied spectral evolution within the individual pulses and obtained such correlations within the pulses. Here we summarize our results of the pulse-wise GRB correlation study. It is worth mentioning that all GRB correlations are still empirical, and we cannot use them in co...

  9. The Interpretation and Implication of the Afterglow of GRB 060218

    CERN Document Server

    Fan, Y; Xu, D; Fan, Yizhong; Piran, Tsvi; Xu, Dong

    2006-01-01

    The nearby GRB 060216/SN 2006aj was an extremely long, weak and very soft GRB. While it was peculiar in many aspects its late ($>10^4$ sec) X-ray afterglow showed a canonical power law decay. Assuming that this component arises due to a relativistic blast wave decelerated by a circumburst matter we infer that the blast wave's kinetic energy was rather high, $5 \\times 10^{50}$ erg, close to what is seen in other GRBs. The lack of a "jet break" implies that the outflow was wide $\\theta_j \\sim 1$. The rather weak early optical emission rules out a dense circumburst wind profile. It also constrains the initial Lorentz factor to be significantly lower than usual, $\\Gamma_{\\rm ini}\\sim 15$. The observed afterglow suggests that the medium surrounding a massive star progenitor (up to distances of $\\sim 10^{17}-10^{18}$ cm) is not the expected dense stellar wind (a similar result was seen in many other bursts and in particular in GRB 030329). This implies that the progenitor's wind was weak during the last 100-1000 ye...

  10. Multi-Color Observations of the GRB000926 Afterglow

    CERN Document Server

    Price, P A; Galama, T J; Reichart, D E; Axelrod, T S; Busche, J; Cline, T; Diercks, A H; Djorgovski, S G; Frail, D A; Gal-Yam, A; Halpern, J; Hunt, J A H M; Hurley, K; Jacoby, B; Kimble, R A; Kulkarni, S R; Mirabal, N; Morrison, G; Pevunova, E O O; Sari, R; Schmidt, B P; Turnshek, D A; Yost, S; Bloom, S J

    2000-01-01

    We present multi-color light-curves of the optical afterglow of GRB 000926. Beginning 1.18 days after the burst, the light curves of this GRB steepen measurably. The existence of such achromatic breaks are usually taken to be an important observational signature that the ejecta are not expanding isotropically, but rather have a collimated jet-like geometry. If we interpret the data in this context, we derive an opening angle of 7 deg, which reduces the energy release compared to an isotropic model by a factor of 120, to 2.2 x 10^{51} erg. To fit the data with a simple jet model requires extinction along the line of sight. The derived A_V is in the range 0.91 -- 0.12 mag, depending on the adopted extinction law and whether the electrons giving rise to the optical emission are undergoing synchrotron cooling or not. Since this is in excess of the expected extinction from our Galaxy, we attribute this to the GRB host. We note that this extinction is typical of a galactic disk, and therefore the event likely took ...

  11. THE EXTREMELY RED HOST GALAXY OF GRB 080207

    International Nuclear Information System (INIS)

    We present optical, near-infrared, and Spitzer IRAC and MIPS observations of the host galaxy of the dark Swift gamma-ray burst GRB 080207. The host is faint, with extremely red optical-infrared colors (R - K = 6.3, 24 μm/R-band flux ∼1000) making it an extremely red object (ERO) and a dust-obscured galaxy (DOG). The spectral energy distribution (SED) shows the clear signature of the 1.6 μm photometric 'bump', typical of evolved stellar populations. We use this bump to establish the photometric redshift zphot as 2.2+0.2-0.3, using a vast library of SED templates, including M 82. The star formation rate (SFR) inferred from the SED fitting is ∼119 Msun yr-1, the stellar mass 3 x 1011 Msun, and AV extinction from 1 to 2 mag. The ERO and DOG nature of the host galaxy of the dark GRB 080207 may be emblematic of a distinct class of dark GRB hosts, with high SFRs, evolved and metal-rich stellar populations, and significant dust extinction within the host galaxy.

  12. AMRVAC and Relativistic Hydrodynamic simulations for GRB afterglow phases

    CERN Document Server

    Meliani, Z; Casse, F; Giannios, D

    2007-01-01

    We apply a novel adaptive mesh refinement code, AMRVAC, to numerically investigate the various evolutionary phases in the interaction of a relativistic shell with its surrounding cold Interstellar Medium (ISM). We do this for both 1D isotropic as well as full 2D jetlike fireball models. This is relevant for Gamma Ray Bursts, and we demonstrate that, thanks to the AMR strategy, we resolve the internal structure of the shocked shell-ISM matter, which will leave its imprint on the GRB afterglow. We determine the deceleration from an initial Lorentz factor $\\gamma=100$ up to the almost Newtonian $\\gamma\\sim{\\cal O}(2)$ phase of the flow. We present axisymmetric 2D shell evolutions, with the 2D extent characterized by their initial opening angle. In such jetlike GRB models, we discuss the differences with the 1D isotropic GRB equivalents. These are mainly due to thermally induced sideways expansions of both the shocked shell and shocked ISM regions. We found that the propagating 2D ultrarelativistic shell does not...

  13. The 050709 macronova and the GRB/macronova connection

    CERN Document Server

    Jin, Zhi-Ping; Li, Xiang; Tanaka, Masaomi; D'Avanzo, Paolo; Fan, Yi-Zhong; Covino, Stefano; Wei, Da-Ming; Piran, Tsvi

    2016-01-01

    We reanalyzed the publicly-available optical/near-infrared afterglow observations of GRB 050709, the first short GRB from which an optical afterglow was detected. The $I$-band/F814W-band light curve is significantly shallower than the $R$-band light curve. This additional low-luminosity soft component can be a signature of a Li-Paczy\\'{n}ski macronova (also known as kilonova) arising from $\\sim 0.05~M_\\odot$ r-process material launched by a compact binary merger. As macronovae are relatively weak and soft they can be identified only within the afterglows of relatively nearby ($z<0.4$) bursts that have sufficient near-infrared/optical data. There are five such events: GRBs 050709, 060505, 060614, 061201 and 130603B. However, the redshift of 061201 is unclear and there is doubt concerning the origin of GRB 060505. Remarkably, evidence for a macronova signature is found in the afterglow of each one of the remaining three events. This demonstrates that macronovae are ubiquitous. The significant mass ejection s...

  14. Gamma-ray burst supernovae as standardizable candles

    Energy Technology Data Exchange (ETDEWEB)

    Cano, Z., E-mail: zewcano@gmail.com [Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Reykjavik (Iceland)

    2014-10-20

    A long-duration gamma-ray burst (GRB) marks the violent end of a massive star. GRBs are rare in the universe, and their progenitor stars are thought to possess unique physical properties such as low metal content and rapid rotation, while the supernovae (SNe) that are associated with GRBs are expected to be highly aspherical. To date, it has been unclear whether GRB-SNe could be used as standardizable candles, with contrasting conclusions found by different teams. In this paper, I present evidence that GRB-SNe have the potential to be used as standardizable candles and show that a statistically significant relation exists between the brightness and width of their decomposed light curves relative to a template SN. Every single nearby spectroscopically identified GRB-SN for which the rest frame and host contributions have been accurately determined follows this relation. Additionally, it is shown that not only GRB-SNe, but perhaps all SNe whose explosions are powered by a central engine may eventually be used as a standardizable candle. Finally, I suggest that the use of GRB-SNe as standardizable candles likely arises from a combination of the viewing angle and similar explosion geometry in each event, the latter of which is influenced by the explosion mechanism of GRB-SNe.

  15. GRB Progenitors and Environment

    OpenAIRE

    Lazzati, Davide

    2005-01-01

    The study and knowledge of the environment of Gamma-Ray Bursts is of great interest from many points of view. For high redshift (z>0.5) events, the structure of the ambient medium is one of the best indicators of the nature and properties of the progenitor. It also tells us about the last stages of the pre-explosion evolution of the progenitor. In addition, it is interesting in its own as a sample of the interstellar medium in a high redshift galaxy. Measures of the density and structure of t...

  16. The Black Hole Central Engine for Ultra-long Gamma-Ray Burst 111209A and Its Associated Supernova 2011kl

    Science.gov (United States)

    Gao, He; Lei, Wei-Hua; You, Zhi-Qiang; Xie, Wei

    2016-08-01

    Recently, the first association between an ultra-long gamma-ray burst (GRB) and a supernova was reported, i.e., GRB 111209A/SN 2011kl, enabling us to investigate the physics of central engines or even progenitors for ultra-long GRBs. In this paper, we inspect the broadband data of GRB 111209A/SN 2011kl. The late-time X-ray light curve exhibits a GRB 121027A-like fallback bump, suggesting a black hole (BH) central engine. We thus propose a collapsar model with fallback accretion for GRB 111209A/SN 2011kl. The required model parameters, such as the total mass and radius of the progenitor star, suggest that the progenitor of GRB 111209A is more likely a Wolf–Rayet star instead of a blue supergiant, and the central engine of this ultra-long burst is a BH. The implications of our results are discussed.

  17. Gamma-Ray Burst Follow-up Observations with STACEE During 2003-2007

    CERN Document Server

    Jarvis, A; Carson, J E; Covault, C E; Driscoll, D D; Fortin, P; Gingrich, D M; Hanna, D S; Kildea, J; Lindner, T; Mukherjee, R; Müller, C; Ong, R A; Ragan, K; Williams, D A; Zweerink, J

    2007-01-01

    The Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) is an atmospheric Cherenkov telescope (ACT) that uses a large mirror array to achieve a relatively low energy threshold. For sources with Crab-like spectra, at high elevations, the detector response peaks near 100 GeV. Gamma-ray burst (GRB) observations have been a high priority for the STACEE collaboration since the inception of the experiment. We present the results of 20 GRB follow-up observations at times ranging from 3 minutes to 15 hours after the burst triggers. Where redshift measurements are available, we place constraints on the intrinsic high-energy spectra of the bursts.

  18. Swift and Fermi observations of the early afterglow of the short Gamma-Ray Burst 090510

    CERN Document Server

    De Pasquale, M; Kuin, N P M; Page, M J; Curran, P A; Zane, S; Oates, S R; Holland, S T; Breeveld, A A; Hoversten, E A; Chincarini, G; Grupe, D

    2009-01-01

    We present the observations of GRB090510 performed by the Fermi Gamma-Ray Space Telescope and the Swift observatory. This is a bright, short burst that shows an extended emission detected in the GeV range. Furthermore, its optical emission initially rises, a feature so far observed only in long bursts, while the X-ray flux shows an initial shallow decrease, followed by a steeper decay. This exceptional behavior enables us to investigate the physical properties of the GRB outflow, poorly known in short bursts. We discuss internal shock and external shock models for the broadband energy emission of this object.

  19. IDENTIFYING THE LOCATION IN THE HOST GALAXY OF THE SHORT GRB 111117A WITH THE CHANDRA SUBARCSECOND POSITION

    International Nuclear Information System (INIS)

    We present our successful Chandra program designed to identify, with subarcsecond accuracy, the X-ray afterglow of the short GRB 111117A, which was discovered by Swift and Fermi. Thanks to our rapid target of opportunity request, Chandra clearly detected the X-ray afterglow, though no optical afterglow was found in deep optical observations. The host galaxy was clearly detected in the optical and near-infrared band, with the best photometric redshift of z=1.31-0.23+0.46 (90% confidence), making it one of the highest known short gamma-ray burst (GRB) redshifts. Furthermore, we see an offset of 1.0 ± 0.2 arcsec, which corresponds to 8.4 ± 1.7 kpc, between the host and the afterglow position. We discuss the importance of using Chandra for obtaining subarcsecond X-ray localizations of short GRB afterglows to study GRB environments.

  20. A Unified Model for GRB Prompt Emission from Optical to Gamma-Rays; a New Type of Standard Candle

    CERN Document Server

    Guiriec, S; Hartmann, D H; Granot, J; Asano, K; Meszaros, P; Gill, R; Gehrels, N; McEnery, J

    2016-01-01

    The origin of prompt emission from gamma ray bursts remains to be an open question. Correlated prompt optical and gamma-ray emission observed in a handful of GRBs strongly suggests a common emission region, but failure to adequately fit the broadband GRB spectrum prompted the hypothesis of different emission mechanisms for the low- and high-energy radiations. We demonstrate that our multi-component model for GRB gamma-ray prompt emission provides an excellent fit to GRB 110205A from optical to gamma-ray energies. Our results show that the optical and highest gamma-ray emissions have the same spatial and spectral origin, which is different from the bulk of the X- and softest gamma-ray radiation. Finally, our accurate redshift estimate for GRB 110205A demonstrates promise for using GRBs as cosmological standard candles.

  1. Spectroscopic Discovery of the Supernova 2003dh Associated with GRB 030329

    CERN Document Server

    Stanek, K Z; Garnavich, P M; Martini, P; Berlind, P; Caldwell, N; Challis, P M; Brown, W; Schild, R; Krisciunas, K; Calkins, M L; Lee, J C; Hathi, N; Jansen, R; Windhorst, R A; Echevarria, L; Eisenstein, D J; Pindor, B; Olszewski, E W; Harding, P; Holland, S T; Bersier, D F

    2003-01-01

    We present early observations of the afterglow of the Gamma-Ray Burst (GRB) 030329 and the spectroscopic discovery of its associated supernova 2003dh. We obtained spectra of the afterglow of GRB 030329 each night from March 30.12 (0.6 days after the burst) to April 8.13 (UT) (9.6 days after the burst). The spectra cover a wavelength range of 350 nm to 850 nm. The early spectra consist of a power-law continuum (F_{nu} ~ nu^{-0.9}) with narrow emission lines originating from HII regions in the host galaxy, indicating a low redshift of z=0.1687. However, our spectra taken after 2003 Apr. 5 show broad peaks in flux characteristic of a supernova. Correcting for the afterglow emission, we find the spectrum of the supernova is remarkably similar to the type Ic `hypernova' SN 1998bw. While the presence of supernovae have been inferred from the light curves and colors of GRB afterglows in the past, this is the first direct, spectroscopic confirmation that a subset of classical gamma-ray bursts originate from supernova...

  2. The Fermi view of gamma-ray bursts

    Science.gov (United States)

    Axelsson, Magnus; Fermi/LAT Collaboration

    2015-08-01

    The Fermi mission has brought great advances in the study of GRBs. Over 1500 gamma-ray bursts (GRBs) have been detected by the Gamma-ray Burst Monitor (GBM), and more than 100 of these are also detected by the Fermi Large Area Telescope (LAT) above 30 MeV. These high-energy detections have revealed previously unknown features in GRB spectra, including additional components and spectral cut-offs, as well as delayed and long-lived GeV emission. Interpretation of these new features has proven to be a source of vigorous debate within the GRB community. I will review recent Fermi-LAT observations of GRBs, ranging from the detection of the long-lived GRB 130427A to the broad-band fits of simultaneous X-ray and gamma-ray data, and what they reveal about the origin of the high-energy emission from GRBs.

  3. GRB 140619B: a short GRB from a binary neutron stars merger leading to the black hole formation

    CERN Document Server

    Muccino, M; Kovacevic, M; Izzo, L; Oliveira, F G; Rueda, J A; Bianco, C L; Enderli, M; Penacchioni, A V; Pisani, G B; Wang, Y; Zaninoni, E

    2014-01-01

    Following the recent identification of the prototypical short GRB 090227B originating from a binary neutron star (NS) merger and forming a black hole (BH), we present here a new example of such sources, GRB 140619B. The time-resolved spectral analysis of the early ~0.2s of the Fermi-GBM data, allows for the identification of the characteristic features of the e^+e^- plasma at transparency (P-GRB): i.e., a thermal spectrum with an observed temperature kT=(324+/-33)keV which represents ~40% of the total source fluence. The subsequent emission, with no thermal spectrum, is identified with the prompt emission. We consequently deduce a theoretical redshift of z=2.67+/-0.37, a total burst energy E+/-=(6.03+/-0.79)x10^{52}erg, a baryon load B=(5.52+/-0.73)x10^{-5}, and a Lorentz factor at transparency Gamma=(1.08+/-0.08)x10^4. From the simulation of the prompt emission we determine the average density of the circumburst medium (CBM), n_CBM=(4.7+/-1.2)x10^{-5}cm^{-3}, typical of the galactic halo environment. These l...

  4. The short gamma-ray burst revolution

    International Nuclear Information System (INIS)

    Swift, a dedicated gamma-ray burst (GRB) satellite with ultrarapid slewing capability, and a suite of ground-based (ESO) telescopes have recently achieved a major breakthrough: detecting the first afterglows of short-duration GRBs. The faintness of these afterglows and the diversity of old and young host galaxies lend support to the emerging 'standard model', in which they are created during the merging of two compact objects. However, the afterglow light-curve properties and possible high-redshift origin of some short bursts suggests that more than one progenitor type may be involved. (orig.)

  5. Physical conditions and element abundances in SN and GRB host galaxies at different redshifts

    CERN Document Server

    Contini, M

    2016-01-01

    We compare the physical parameters and the relative abundances calculated throughout supernova (SN) and gamma-ray burst (GRB) host galaxies by the detailed modelling of the spectra. The results show that : 1) shock velocities are lower in long period GRB (LGRB) than in SN host galaxies. 2) O/H relative abundance in SN hosts are scattered within a range 8.0 10^5 K. Ts in LGRB hosts are 3-8 10^4 K. 4) Ha increases with the ionization parameter U. We suggest that SN-host symbiosis is stronger in terms of host galaxy activity than GRB-host in the range of energies related to the near UV - optical - near IR spectra.

  6. A Detection of Molecular Gas Emission in the Host Galaxy of GRB 080517

    CERN Document Server

    Stanway, E R; Tanvir, N R; Wiersema, K; van der Laan, T P R

    2014-01-01

    We have observed the host galaxy of the low redshift, low luminosity GRB 080517 at 105.8 GHz using the IRAM Plateau de Bure interferometer. We detect an emission line with integrated flux S.delta{nu} = 0.39 +/- 0.05 Jy km/s - consistent both spatially and in velocity with identification as the J=1-0 rotational transition of carbon monoxide (CO) at the host galaxy redshift. This represents only the third long GRB host galaxy with molecular gas detected in emission. The inferred molecular gas mass, M_H2 ~ 6.3 x 10^8 M_sun, implies a gas consumption timescale of ~40 Myr if star formation continues at its current rate. Similar short timescales appear characteristic of the long GRB population with CO observations to date, suggesting that the gamma-ray burst in these sources occurs towards the end of their star formation episode.

  7. Simulations of GRB detections with the ECLAIRs telescope onboard the future SVOM mission

    CERN Document Server

    Antier, S; Cordier, B; Gros, A; Götz, D; Lachaud, C

    2015-01-01

    The soft gamma-ray telescope ECLAIRs with its Scientific Trigger Unit is in charge of detecting Gamma-Ray Bursts (GRBs) on-board the future SVOM satellite. Using the "scientific software model" (SSM), we study the efficiency of both implemented trigger algorithms, the Count-Rate Trigger for time-scales below 20s and the Image Trigger for larger ones. The SMM provides a simulation of ECLAIRs with photon projection through the coded-mask onto the detection plane. We developed an input GRB database for the SSM based on GRBs light curves detected by the Fermi GBM instrument. We extrapolated the GRB spectra into the ECLAIRs band (4-120 keV) and projected them onto the detection plane, superimposed with cosmic extragalactic background photons (CXB). Several simulations were performed by varying the GRB properties (fluxes and positions in the field of view). We present first results of this study in this paper.

  8. When Do Internal Shocks End and External Shocks Begin? Early-Time Broadband Modelling of GRB 051111

    CERN Document Server

    Butler, N R; Perley, D; Huang, K Y; Urata, Y; Prochaska, J X; Bloom, J S; Filippenko, A V; Foley, R J; Kocevski, D; Chen, H W; Qiu, Y; Kuo, P H; Huang, F Y; Ip, W H; Tamagawa, T; Onda, K; Tashiro, M; Makishima, K; Nishihara, S; Sarugaku, Y

    2006-01-01

    Even with the renaissance in gamma-ray burst (GRB) research fostered by the Swift satellite, few bursts have both contemporaneous observations at long wavelengths and exquisite observations at later times across the electromagnetic spectrum. We present here contemporaneous imaging with the KAIT robotic optical telescope, dense optical sampling with Lulin, and supplemented with infrared data from PAIRITEL and radio to gamma-ray data from the literature. For the first time, we can test the constancy of microphysical parameters in the internal-external shock paradigm and carefully trace the flow of energy from the GRB to the surrounding medium. KAIT data taken 10^21 cm^-2), indicate a low dust-to-metals ratio and a possible over-abundance of the light metals. An apparent small ratio of total to selective extinction (R_V~ 2) and time constancy of both optical and X-ray spectra argue against dust destruction by the GRB itself.

  9. GRB Potential of ESA Gaia

    Czech Academy of Sciences Publication Activity Database

    Hudec, René; Šimon, Vojtěch

    Les Ulis : EDP Sciences, 2013, s. 239-243. ISBN 9782759810024. ISSN 1633-4760. - (EAS Publications Series. 61). [Fall Gamma Ray Burst Symposium on 15 years of Gamma-Ray Burst s afterglows. Malaga (ES), 08.10.2012-12.10.2012] Institutional support: RVO:67985815 Keywords : gamma-ray burst s * orphan afterglows * jet Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  10. Rossi Prize Lecture: Gamma Ray Bursts: Origins and Consequences

    Science.gov (United States)

    Meszaros, P.

    2000-12-01

    Some of the major stepping stones towards uncovering the mystery of gamma ray bursts will be discussed. This is an unfinished process, new observations being expected in the near future. I will review the current observational status, and discuss the present theoretical understanding of GRB, as well as the possible impact of future missions and experiments.

  11. Closest Gamma Ray Burst Providing Scientists With Crucial Test for Burst Physics

    Science.gov (United States)

    2003-05-01

    The closest Gamma Ray Burst (GRB) yet known is providing astronomers with a rare opportunity to gain information vital to understanding these powerful cosmic explosions. Extremely precise radio-telescope observations already have ruled out one proposed mechanism for the bursts. "This is the closest and brightest GRB we've ever seen, and we can use it to decipher the physics of how these bursts work," said Greg Taylor of the National Radio Astronomy Observatory (NRAO) in Socorro, NM. Taylor worked with Dale Frail, also of the NRAO, along with Prof. Shri Kulkarni and graduate student Edo Berger of Caltech in studying a GRB detected on March 29, 2003. The scientists presented their findings to the American Astronomical Society's meeting in Nashville, TN. VLBA image of GRB 030329 VLBA IMAGE of GRB 030329 CREDIT: NRAO/AUI/NSF (Click on Image for Larger Version) Taylor and Frail used the National Science Foundation's (NSF) Very Long Baseline Array (VLBA) and other radio telescopes to study the burst, known as GRB 030329. In a series of observations from April 1 to May 19, they determined the size of the expanding "fireball" from the burst and measured its position in the sky with great precision. At a distance of about 2.6 billion light-years, GRB 030329 is hardly next door. However, compared to other GRBs at typical distances of 8-10 billion light-years, it presents an easier target for study. "We only expect to see one burst per decade this close," said Frail. The precise measurement of the object's position allowed the scientists to show that one theoretical model for GRBs can be ruled out. This model, proposed in 2000, says that the radio-wave energy emitted by the GRB comes from "cannonballs" of material shot from the explosion at extremely high speeds. "The 'cannonball model' predicted that we should see the radio-emitting object move across the sky by a specific amount. We have not seen that motion," Taylor said. The currently standard "fireball model" of GRBs

  12. MAGIC upper limits on the GRB 090102 afterglow

    Science.gov (United States)

    Aleksić, J.; Ansoldi, S.; Antonelli, L. A.; Antoranz, P.; Babic, A.; de Almeida, U. Barres; Barrio, J. A.; González, J. Becerra; Bednarek, W.; Berger, K.; Bernardini, E.; Biland, A.; Blanch, O.; Bock, R. K.; Boller, A.; Bonnefoy, S.; Bonnoli, G.; Borracci, F.; Bretz, T.; Carmona, E.; Carosi, A.; Fidalgo, D. Carreto; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Cossio, L.; Covino, S.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Caneva, G.; De Lotto, B.; Mendez, C. Delgado; Doert, M.; Domínguez, A.; Prester, D. Dominis; Dorner, D.; Doro, M.; Eisenacher, D.; Elsaesser, D.; Farina, E.; Ferenc, D.; Fonseca, M. V.; Font, L.; Frantzen, K.; Fruck, C.; López, R. J. García; Garczarczyk, M.; Terrats, D. Garrido; Gaug, M.; Giavitto, G.; Godinović, N.; Munoz, A. González; Gozzini, S. R.; Hadamek, A.; Hadasch, D.; Herrero, A.; Hose, J.; Hrupec, D.; Idec, W.; Kadenius, V.; Knoetig, M. L.; Krähenbühl, T.; Krause, J.; Kushida, J.; Barbera, A. La; Lelas, D.; Lewandowska, N.; Lindfors, E.; Lombardi, S.; López-Coto, R.; López, M.; López-Oramas, A.; Lorenz, E.; Lozano, I.; Makariev, M.; Mallot, K.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Marcote, B.; Mariotti, M.; Martínez, M.; Masbou, J.; Mazin, D.; Menzel, U.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Moldón, J.; Moralejo, A.; Munar-Adrover, P.; Nakajima, D.; Niedzwiecki, A.; Nilsson, K.; Nowak, N.; Orito, R.; Overkemping, A.; Paiano, S.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Partini, S.; Persic, M.; Prada, F.; Moroni, P. G. Prada; Prandini, E.; Preziuso, S.; Puljak, I.; Reichardt, I.; Reinthal, R.; Rhode, W.; Ribó, M.; Rico, J.; Garcia, J. Rodriguez; Rügamer, S.; Saggion, A.; Saito, K.; Saito, T.; Salvati, M.; Satalecka, K.; Scalzotto, V.; Scapin, V.; Schultz, C.; Schweizer, T.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Snidaric, I.; Sobczynska, D.; Spanier, F.; Stamatescu, V.; Stamerra, A.; Storz, J.; Sun, S.; Surić, T.; Takalo, L.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Thaele, J.; Tibolla, O.; Torres, D. F.; Toyama, T.; Treves, A.; Uellenbeck, M.; Vogler, P.; Wagner, R. M.; Weitzel, Q.; Zandanel, F.; Zanin, R.; Bouvier, A.; Hayashida, M.; Tajima, H.; Longo, F.

    2014-02-01

    Indications of a GeV component in the emission from gamma-ray bursts (GRBs) are known since the Energetic Gamma-Ray Experiment Telescope observations during the 1990s and they have been confirmed by the data of the Fermi satellite. These results have, however, shown that our understanding of GRB physics is still unsatisfactory. The new generation of Cherenkov observatories and in particular the MAGIC telescope, allow for the first time the possibility to extend the measurement of GRBs from several tens up to hundreds of GeV energy range. Both leptonic and hadronic processes have been suggested to explain the possible GeV/TeV counterpart of GRBs. Observations with ground-based telescopes of very high energy (VHE) photons (E > 30 GeV) from these sources are going to play a key role in discriminating among the different proposed emission mechanisms, which are barely distinguishable at lower energies. MAGIC telescope observations of the GRB 090102 (z = 1.547) field and Fermi Large Area Telescope data in the same time interval are analysed to derive upper limits of the GeV/TeV emission. We compare these results to the expected emissions evaluated for different processes in the framework of a relativistic blastwave model for the afterglow. Simultaneous upper limits with Fermi and a Cherenkov telescope have been derived for this GRB observation. The results we obtained are compatible with the expected emission although the difficulties in predicting the HE and VHE emission for the afterglow of this event makes it difficult to draw firmer conclusions. Nonetheless, MAGIC sensitivity in the energy range of overlap with space-based instruments (above about 40 GeV) is about one order of magnitude better with respect to Fermi. This makes evident the constraining power of ground-based observations and shows that the MAGIC telescope has reached the required performance to make possible GRB multiwavelength studies in the VHE range.

  13. The Energy Dependence of GRB Minimum Variability Timescales

    Science.gov (United States)

    Golkhou, V. Zach; Butler, Nathaniel R.; Littlejohns, Owen M.

    2015-10-01

    We constrain the minimum variability timescales for 938 gamma-ray bursts (GRBs) observed by the Fermi/Gamma-ray Burst Monitor instrument prior to 2012 July 11. The tightest constraints on progenitor radii derived from these timescales are obtained from light curves in the hardest energy channel. In the softer bands—or from measurements of the same GRBs in the hard X-rays from Swift—we show that variability timescales tend to be a factor of two to three longer. Applying a survival analysis to account for detections and upper limits, we find median minimum timescale in the rest frame for long-duration and short-duration GRBs of 45 and 10 ms, respectively. Less than 10% of GRBs show evidence for variability on timescales below 2 ms. These shortest timescales require Lorentz factors ≳ 400 and imply typical emission radii R≈ 1× {10}14 cm for long-duration GRBs and R≈ 3× {10}13 cm for short-duration GRBs. We discuss implications for the GRB fireball model and investigate whether or not GRB minimum timescales evolve with cosmic time.

  14. Jet or Shock Breakout? The Low-Luminosity GRB 060218

    Science.gov (United States)

    Irwin, Christopher; Chevalier, Roger

    2016-01-01

    We consider a model for the long-duration, low-luminosity gamma-ray burst GRB 060218 that plausibly accounts for multiwavelength observations to day 20. The components of our model are: (1) a long-lived (tj ~ 3000 s) central engine and accompanying low-luminosity (Lj ~ 1045 erg s-1), mildly relativistic jet; (2) a low-mass (~ 10-2 Msun) envelope surrounding the progenitor star; and (3) a modest amount of dust (AV ~ 0.1) in the circumstellar or interstellar environment. Blackbody emission from the transparency radius in a low-power jet outflow can fit the prompt thermal X-ray emission, and the prompt nonthermal X-rays and γ-rays may be produced via Compton scattering of thermal photons from hot leptons in the jet interior or the external shocks. The later mildly relativistic phase of this outflow can produce the radio emission via synchrotron radiation from the forward shock. Meanwhile, interaction of the associated SN 2006aj with a circumstellar envelope extending to ~ 1013 cm can explain the early optical peak. The X-ray afterglow can be interpreted as a light echo of the prompt emission from dust at ~ 30 pc. Our model is a plausible alternative to that of Nakar, who recently proposed shock breakout of a jet smothered by an extended envelope as the source of prompt emission. Both our results and Nakar's suggest that ultra-long bursts such as GRB 060218 and GRB 100316D may originate from unusual progenitors with extended circumstellar envelopes, and that a jet is necessary to decouple the prompt high-energy emission from the supernova.

  15. Investigation of Primordial Black Hole Bursts using Interplanetary Network Gamma-ray Bursts

    CERN Document Server

    Ukwatta, T N; MacGibbon, J H; Svinkin, D S; Aptekar, R L; Golenetskii, S V; Frederiks, D D; Pal'shin, V D; Goldsten, J; Boynton, W; Fellows, C; Harshman, K; Mitrofanov, I G; Golovin, D V; Kozyrev, A S; Litvak, M L; Sanin, A B; Rau, A; Kienlin, A; Zhang, X; Briggs, M S; Connaughton, V; Meegan, C; Yamaoka, K; Fukazawa, Y; Ohno, M; Ohmori, N; Takahashi, T; Tashiro, M; Terada, Y; Murakami, T; Makishima, K; Feroci, M; Frontera, F; Guidorzi, C; Barthelmy, S; Cline, T; Gehrels, N; Cummings, J; Krimm, H A; Smith, D M; McTiernan, J

    2015-01-01

    The detection of a gamma-ray burst (GRB) in the solar neighborhood would have very important implications for GRB phenomenology. The leading theories for cosmological GRBs would not be able to explain such events. The final bursts of evaporating Primordial Black Holes (PBHs), however, would be a natural explanation for local GRBs. We present a novel technique that can constrain the minimum distance to gamma-ray bursts using detections from widely separated spacecraft. We applied this method to constrain distances to a sample of 36 short duration GRBs detected by the Interplanetary Network (IPN) that show observational properties that are expected from PBH evaporations. These bursts have minimum possible distances in the 10^13-10^18 cm (7-10^5 AU) range, consistent with the expected PBH energetics and with a possible origin in the solar neighborhood, although none of the bursts can be unambiguously demonstrated to be local. Assuming these bursts are real PBH events, we estimate for the first time lower limits ...

  16. A catalog of optical/near-infrared data on GRB afterglows in the pre-Swift era. I. Light curve information

    OpenAIRE

    Kann, D. A.; Zeh, A.; Klose, S.

    2005-01-01

    The present catalog is the result of our attempts to collect all published photometric data on GRB afterglows observed in the pre-Swift era by the end of 2004 in order to gain statistical insight on the phenomenology of GRB afterglows. Part I contains all published data on GRB afterglows in filters we used in Zeh, Klose, & Kann (2005) to create reference light curves and derive light curve parameters (mostly R band, but a few bursts have better data in other colors) including the correspondin...

  17. HIGH-ENERGY EMISSION OF GRB 130427A: EVIDENCE FOR INVERSE COMPTON RADIATION

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Yi-Zhong; Zhang, Fu-Wen; He, Hao-Ning; Zhou, Bei; Yang, Rui-Zhi; Jin, Zhi-Ping; Wei, Da-Ming [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Tam, P. H. T. [Institute of Astronomy and Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Liang, Yun-Feng, E-mail: yzfan@pmo.ac.cn, E-mail: fwzhang@pmo.ac.cn, E-mail: dmwei@pmo.ac.cn [Department of Physics, Guangxi University, Guangxi 530004 (China)

    2013-10-20

    A nearby superluminous burst GRB 130427A was simultaneously detected by six γ-ray space telescopes (Swift, the Fermi GLAST Burst Monitor (GBM)/Large Area Telescope, Konus-Wind, SPI-ACS/INTEGRAL, AGILE, and RHESSI) and by three RAPTOR full-sky persistent monitors. The isotropic γ-ray energy release is ∼10{sup 54} erg, rendering it the most powerful explosion among gamma-ray bursts (GRBs) with a redshift z ≤ 0.5. The emission above 100 MeV lasted about one day, and four photons are at energies greater than 40 GeV. We show that the count rate of 100 MeV-100 GeV emission may be mainly accounted for by the forward shock synchrotron radiation and the inverse Compton radiation likely dominates at GeV-TeV energies. In particular, an inverse Compton radiation origin is favored for the ∼(95.3, 47.3, 41.4, 38.5, 32) GeV photons arriving at t ∼ (243, 256.3, 610.6, 3409.8, 34366.2) s after the trigger of Fermi-GBM. Interestingly, the external inverse Compton scattering of the prompt emission (the second episode, i.e., t ∼ 120-260 s) by the forward-shock-accelerated electrons is expected to produce a few γ-rays at energies above 10 GeV, while five were detected in the same time interval. A possible unified model for the prompt soft γ-ray, optical, and GeV emission of GRB 130427A, GRB 080319B, and GRB 090902B is outlined. Implications of the null detection of >1 TeV neutrinos from GRB 130427A by IceCube are discussed.

  18. HIGH-ENERGY EMISSION OF GRB 130427A: EVIDENCE FOR INVERSE COMPTON RADIATION

    International Nuclear Information System (INIS)

    A nearby superluminous burst GRB 130427A was simultaneously detected by six γ-ray space telescopes (Swift, the Fermi GLAST Burst Monitor (GBM)/Large Area Telescope, Konus-Wind, SPI-ACS/INTEGRAL, AGILE, and RHESSI) and by three RAPTOR full-sky persistent monitors. The isotropic γ-ray energy release is ∼1054 erg, rendering it the most powerful explosion among gamma-ray bursts (GRBs) with a redshift z ≤ 0.5. The emission above 100 MeV lasted about one day, and four photons are at energies greater than 40 GeV. We show that the count rate of 100 MeV-100 GeV emission may be mainly accounted for by the forward shock synchrotron radiation and the inverse Compton radiation likely dominates at GeV-TeV energies. In particular, an inverse Compton radiation origin is favored for the ∼(95.3, 47.3, 41.4, 38.5, 32) GeV photons arriving at t ∼ (243, 256.3, 610.6, 3409.8, 34366.2) s after the trigger of Fermi-GBM. Interestingly, the external inverse Compton scattering of the prompt emission (the second episode, i.e., t ∼ 120-260 s) by the forward-shock-accelerated electrons is expected to produce a few γ-rays at energies above 10 GeV, while five were detected in the same time interval. A possible unified model for the prompt soft γ-ray, optical, and GeV emission of GRB 130427A, GRB 080319B, and GRB 090902B is outlined. Implications of the null detection of >1 TeV neutrinos from GRB 130427A by IceCube are discussed

  19. Rapid, Machine-Learned Resource Allocation: Application to High-redshift GRB Follow-up

    CERN Document Server

    Morgan, Adam N; Richards, Joseph W; Broderick, Tamara; Butler, Nathaniel R; Bloom, Joshua S

    2011-01-01

    As the number of observed Gamma-Ray Bursts (GRBs) continues to grow, follow-up resources need to be used more efficiently in order to maximize science output from limited telescope time. As such, it is becoming increasingly important to rapidly identify bursts of interest as soon as possible after the event, before the afterglows fade beyond detectability. Studying the most distant (highest redshift) events, for instance, remains a primary goal for many in the field. Here we present our Random forest Automated Triage Estimator for GRB redshifts (RATE GRB-z) for rapid identification of high-redshift candidates using early-time metrics from the three telescopes onboard Swift. While the basic RATE methodology is generalizable to a number of resource allocation problems, here we demonstrate its utility for telescope-constrained follow-up efforts with the primary goal to identify and study high-z GRBs. For each new GRB, RATE GRB-z provides a recommendation - based on the available telescope time - of whether the e...

  20. GRB 090423:Marking the death of a massive star at z=8.2

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    GRB 090423 is the new high-z record holder of Gamma-ray bursts(GRBs) with z-8.2.We present a detailed analysis of both the spectral and temporal features of GRB 090423 observed with Swift/BAT and Fermi/GBM.We find that the T90 observed with BAT in the 15-150 keV band is 13.2 s,corresponding to-1.4 s at z=8.2.It once again gives rise to the issue of whether the progenitors of high-z GRBs are massive stars or mergers since the discovery of GRB 080913 at z=6.7.In comparison with the T90 distribution in the burst frame of the current redshift-known GRB sample,we find that it is marginally grouped into the long group(Type II GRBs).The spectrum observed with both BAT and GBM is well fitted by a power-law with exponential cutoff,which yields an Ep=(50.4±7.0) keV.The event satisfies the Amati-relation well for Type II GRBs within their 3σ uncertainty range.Our results indicate that this event would be produced by the death of a massive star.Based on the Amati-relation,we derive its distance modulus,which follows the Hubble diagram of the concordance cosmology model at a redshift of-8.2.

  1. Machine Learning Model of the Swift/BAT Trigger Algorithm for Long GRB Population Studies

    CERN Document Server

    Graff, Philip B; Baker, John G; Sakamoto, Takanori

    2015-01-01

    To draw inferences about gamma-ray burst (GRB) source populations based on Swift observations, it is essential to understand the detection efficiency of the Swift burst alert telescope (BAT). This study considers the problem of modeling the Swift/BAT triggering algorithm for long GRBs, a computationally expensive procedure, and models it using machine learning algorithms. A large sample of simulated GRBs from Lien 2014 is used to train various models: random forests, boosted decision trees (with AdaBoost), support vector machines, and artificial neural networks. The best models have accuracies of $\\gtrsim97\\%$ ($\\lesssim 3\\%$ error), which is a significant improvement on a cut in GRB flux which has an accuracy of $89.6\\%$ ($10.4\\%$ error). These models are then used to measure the detection efficiency of Swift as a function of redshift $z$, which is used to perform Bayesian parameter estimation on the GRB rate distribution. We find a local GRB rate density of $n_0 \\sim 0.48^{+0.41}_{-0.23} \\ {\\rm Gpc}^{-3} {\\...

  2. Slope evolution of GRB correlations and cosmology

    CERN Document Server

    Dainotti, Maria Giovanna; Piedipalumbo, Ester; Capozziello, Salvatore

    2013-01-01

    Gamma -ray bursts (GRBs) observed up to redshifts $z>9.4$ can be used as possible probes to test cosmological models. Here we show how changes of the slope of the {\\it luminosity $L^*_X$ -break time $T^*_a$} correlation in GRB afterglows, hereafter the LT correlation, affect the determination of the cosmological parameters. With a simulated data set of 101 GRBs with a central value of the correlation slope that differs on the intrinsic one by a $5\\sigma$ factor, we find an overstimated value of the matter density parameter, $\\Omega_M$, compared to the value obtained with SNe Ia, while the Hubble constant, $H_0$, best fit value is still compatible in 1$\\sigma$ compared to other probes. We show that this compatibility of $H_0$ is due to the large intrinsic scatter associated with the simulated sample. Instead, if we consider a subsample of high luminous GRBs ($HighL$), we find that both the evaluation of $H_0$ and $\\Omega_M$ are not more compatible in 1$\\sigma$ and $\\Omega_M$ is underestimated by the $13\\%$. Ho...

  3. The Host Galaxy of GRB 990123

    CERN Document Server

    Bloom, J S; Djorgovski, S G; Harrison, F A; Koresko, C D; Neugebauer, G; Armus, L; Frail, D A; Gal, R R; Sari, R; Squires, G L; Illingworth, G D; Kelson, D D; Chaffee, F H; Goodrich, R; Feroci, M; Costa, E; Piro, L; Frontera, F; Mao, S; Akerlof, Carl W; McKay, T A; Kulkarni, S R

    1999-01-01

    We present deep images of the field of gamma-ray burst (GRB) 990123 obtained in a broad-band UV/visible bandpass with the Hubble Space Telescope, and deep near-infrared images obtained with the Keck-I 10-m telescope. Both the HST and Keck images show that the optical transient (OT) is clearly offset by 0.6 arcsec from an extended object, presumably the host galaxy. This galaxy is the most likely source of the metallic-line absorption at z = 1.6004 seen in the spectrum of the OT. With magnitudes V_{C} ~ 24.6 +/- 0.2 and K = 21.65 +/- 0.30 mag this corresponds to an L ~ 0.7 L_* galaxy, assuming that it is located at z = 1.6. The estimated unobscured star formation rate is SFR ~ 6 M_sun/yr, which is not unusually high for normal galaxies at comparable redshifts. The strength of the observed metallic absorption lines is suggestive of a relatively high metallicity of the gas, and thus of a chemically evolved system which may be associated with a massive galaxy. It is also indicative of a high column density of the...

  4. GRB 070125 and the environments of spectral-line poor afterglow absorbers

    CERN Document Server

    De Cia, A; Wiersema, K; van der Horst, A J; Vreeswijk, P M; Björnsson, G; Postigo, A de Ugarte; Jakobsson, P; Levan, A J; Rol, E; Schulze, S; Tanvir, N R

    2011-01-01

    GRB 070125 is among the most energetic bursts detected and the most extensively observed so far. Nevertheless, unresolved issues are still open in the literature on the physics of the afterglow and on the GRB environment. In particular, GRB 070125 was claimed to have exploded in a galactic halo environment, based on the uniqueness of the optical spectrum and the non-detection of an underlying host galaxy. In this work we collect all publicly available data and address these issues by modelling the NIR-to-X-ray spectral energy distribution (SED) and studying the high signal-to-noise VLT/FORS afterglow spectrum in comparison with a larger sample of GRB absorbers. The SED reveals a synchrotron cooling break in the UV, low equivalent hydrogen column density and little reddening caused by a LMC- or SMC-type extinction curve. From the weak MgII absorption at z=1.5477 in the spectrum, we derived logN(MgII)=12.96+0.13-0.18 and upper limits on the ionic column density of several metals. These suggest that the GRB abso...

  5. GRB 130606A within a sub-DLA at redshift 5.91

    CERN Document Server

    Castro-Tirado, A J; Ellison, S L; Jelínek, M; Martín-Carrillo, A; Bromm, V; Gorosabel, J; Bremer, M; Winters, J M; Hanlon, L; Meegan, S; Topinka, M; Pandey, S B; Guziy, S; Jeong, S; Sonbas, E; Pozanenko, A S; Cunniffe, R; Fernández-Muñoz, R; Ferrero, P; Gehrels, N; Hudec, R; Kubánek, P; Lara-Gil, O; Muñoz-Martínez, V F; Pérez-Ramírez, D; Štrobl, J; Álvarez-Iglesias, C; Inasaridze, R; Rumyantsev, V; Volnova, A; Hellmich, S; Mottola, S; Cerón, J M Castro; Cepa, J; Göğüş, E; Güver, T; Taş, Ö Önal; Park, I H; Sabau-Graziati, L; Tejero, A

    2013-01-01

    Events such as GRB130606A at z=5.91, offer an exciting new window into pre-galactic metal enrichment in these very high redshift host galaxies. We study the environment and host galaxy of GRB 130606A, a high-z event, in the context of a high redshift population of GRBs. We have obtained multiwavelength observations from radio to gamma-ray, concentrating particularly on the X-ray evolution as well as the optical photometric and spectroscopic data analysis. With an initial Lorentz bulk factor in the range \\Gamma_0 ~ 65-220, the X-ray afterglow evolution can be explained by a time-dependent photoionization of the local circumburst medium, within a compact and dense environment. The host galaxy is a sub-DLA (log N (HI) = 19.85+/-0.15), with a metallicity content in the range from ~1/7 to ~1/60 of solar. Highly ionized species (N V and Si IV) are also detected. This is the second highest redshift burst with a measured GRB-DLA metallicity and only the third GRB absorber with sub-DLA HI column density. GRB ' lightho...

  6. On the Host Galaxy of GRB 150101B and the Associated Active Galactic Nucleus

    CERN Document Server

    Xie, Chen; Wang, Junfeng; Liu, Tong; Jiang, Xiaochuan

    2016-01-01

    We present a multi-wavelength analysis of the host galaxy of short-duration gamma-ray burst (GRB) 150101B. Follow-up optical and X-ray observations suggested that the host galaxy, 2MASX J12320498-1056010, likely harbors a low-luminosity active galactic nuclei (AGN). Our modeling of the spectral energy distribution (SED) has confirmed the nature of the AGN, making it the first reported GRB host that contains an AGN. We have also found the host galaxy is a massive elliptical galaxy with stellar population of $\\sim 5.7\\ Gyr$, one of the oldest among the short-duration GRB hosts. Our analysis suggests that the host galaxy can be classified as an X-ray bright, optically normal galaxy (XBONG), and the central AGN is likely dominated by a radiatively inefficient accretion flow (RIAF). Our work explores interesting connection that may exist between GRB and AGN activities of the host galaxy, which can help understand the host environment of the GRB events and the roles of AGN feedback.

  7. Shocked by the Very Bright Radio Flare and Afterglow of GRB 130427A

    Science.gov (United States)

    van der Horst, Alexander J.

    2014-01-01

    Gamma-ray burst (GRB) 130427A was extremely bright across the electromagnetic spectrum, with emission spanning 16 orders of magnitude in observing frequency, from almost 100 GeV gamma-rays down to the GHz radio regime. While the intrinsic luminosity of this GRB was not extreme compared to other GRBs, it displayed the largest measured fluence of the last three decades due to its proximity with a redshift of 0.34. One of the most notable characteristics of this GRB was its bright radio emission, in particular the radio flare which has been observed only a few times in other GRBs and is usually attributed to the reverse shock moving back into the GRB jet. Here we present radio observations with unprecedented temporal coverage at three observing frequencies obtained with the Westerbork Synthesis Radio Telescope (WSRT) and the Arcminute Microkelvin Imager (AMI). AMI had the earliest radio detection at 8 hours after the initial flash of gamma-rays, catching the radio flare on the rise. The 12-hour WSRT observations in the first few days enabled a detailed study of the short time-scale behavior at radio wavelengths. Besides our observations of the radio flare and afterglow up to three months after the gamma-ray trigger, we present our results for modeling the radio light curves together with the broadband data set in various other wavelength regimes, enabling us to determine physical parameters of both the reverse and forward shock of this enigmatic GRB.

  8. The ECLAIRs GRB-trigger telescope on-board the future mission SVOM

    CERN Document Server

    Schanne, Stéphane; Atteia, Jean-Luc; Godet, Olivier; Lachaud, Cyril; Mercier, Karine

    2015-01-01

    The Space-based multi-band astronomical Variable Objects Monitor (SVOM) is an approved satellite mission for Gamma-Ray Burst (GRB) studies, developed in cooperation between the Chinese National Space Agency (CNSA), the Chinese Academy of Sciences (CAS), the French Space Agency (CNES) and French laboratories. SVOM entered Phase B in 2014 and is scheduled for launch in 2021. SVOM will provide fast and accurate GRB localizations, and determine the temporal and spectral properties of the GRB emission, thanks to a set of 4 on-board instruments. The trigger system of the coded-mask telescope ECLAIRs images the sky in the 4-120 keV energy range, in order to detect and localize GRBs in its 2 sr-wide field of view. The low-energy threshold of ECLAIRs is well suited for the detection of highly redshifted GRB. The high-energy coverage is extended up to 5 MeV thanks to the non-imaging gamma-ray spectrometer GRM. GRB alerts are sent in real-time to the ground observers community, and a spacecraft slew is performed in orde...

  9. Constraining the GRB-magnetar model by means of the Galactic pulsar population

    CERN Document Server

    Rea, Nanda; Pons, Jose' A; Perna, Rosalba; Dainotti, Maria G; Miralles, Juan A; Torres, Diego F

    2015-01-01

    A large fraction of Gamma Ray Bursts (GRBs) displays an X-ray plateau phase within <10^{5} s from the prompt emission, proposed to be powered by the spin-down energy of a rapidly spinning newly born magnetar. In this work we use the properties of the Galactic neutron star population to constrain the GRB-magnetar scenario. We re-analyze the X-ray plateaus of all Swift GRBs with known redshift, between January 2005 and August 2014. From the derived initial magnetic field distribution for the possible magnetars left behind by the GRBs, we study the evolution and properties of a simulated GRB-magnetar population using numerical simulations of magnetic field evolution, coupled with Monte Carlo simulations of Pulsar Population Synthesis in our Galaxy. We find that if the GRB X-ray plateaus are powered by the rotational energy of a newly formed magnetar, the current observational properties of the Galactic magnetar population are not compatible with being formed within the GRB scenario (regardless of the GRB type...

  10. The Early Optical Afterglow of GRB 030418 and Progenitor Mass Loss

    CERN Document Server

    Rykoff, E S; Price, P A; Akerlof, C W; Ashley, M C B; Bizyaev, D V; Garradd, G J; McKay, T A; McNaught, R H; Phillips, A; Quimby, R; Schaefer, B; Schmidt, B; Vestrand, W T; Wheeler, J C; Wren, J

    2004-01-01

    The ROTSE-IIIa telescope and the SSO-40 inch telescope, both located at Siding Spring Observatory, imaged the early time afterglow of GRB 030418. In this report we present observations of the early afterglow, first detected by the ROTSE-IIIa telescope 211 s after the start of the burst, and only 76 s after the end of the gamma-ray activity. We detect optical emission that rises for ~600 s, slowly varies around R=17.3 mag for ~1400 s, and then fades as a power law of index alpha=-1.36. Additionally, the ROTSE-IIIb telescope, located at McDonald Observatory, imaged the early time afterglow of GRB 030723. The behavior of this light curve was qualitatively similar to that of GRB 030418, but two magnitudes dimmer. These two afterglows are dissimilar to other afterglows such as GRB 990123 and GRB 021211. We investigate whether the early afterglow can be attributed to a synchrotron break in a cooling synchrotron spectrum as it passes through the optical band, but find this model is unable to accurately describe the ...

  11. A tale of two GRB-SNe at a common redshift of z = 0.54

    CERN Document Server

    Cano, Z; Guidorzi, C; Margutti, R; Svensson, K M; Kobayashi, S; Melandri, A; Wiersema, K; Pozanenko, A; van der Horst, A J; Pooley, G G; Fernandez-Soto, A; Castro-Tirado, A J; Postigo, A de Ugarte; Im, M; Kamble, A P; Sahu, D; Alonso-Lorite, J; Anupama, G; Bibby, J L; Burgdorf, M J; Clay, N; Curran, P A; Fatkhullin, T A; Fruchter, A S; Garnavich, P; Gomboc, A; Gorosabel, J; Graham, J F; Gurugubelli, U; Haislip, J; Huang, K; Huxor, A; Ibrahimov, M; Jeon, Y; Jeon, Y-B; Ivarsen, K; Kasen, D; Klunko, E; Kouveliotou, C; LaCluyze, A; Levan, A J; Loznikov, V; Mazzali, P A; Moskvitin, A S; Mottram, C; Mundell, C G; Nugent, P E; Nysewander, M; O'Brien, P T; Park, W -K; Peris, V; Pian, E; Reichart, D; Rhoads, J E; Rol, E; Rumyantsev, V; Scowcroft, V; Shakhovskoy, D; Small, E; Smith, R J; Sokolov, V V; Starling, R L C; Steele, I; Strom, R G; Tanvir, N R; Tsapras, Y; Urata, Y; Vaduvescu, O; Volnova, A; Volvach, A; Wijers, R A M J; Woosley, S E; Young, D R

    2010-01-01

    We present ground-based and HST optical observations of the optical transients (OTs) of long-duration Gamma Ray Bursts (GRBs) 060729 and 090618, both at a redshift of z = 0.54. For GRB 060729, bumps are seen in the optical light curves (LCs), and the late-time broadband spectral energy distributions (SEDs) of the OT resemble those of local type Ic supernovae (SNe). For GRB 090618, the dense sampling of our optical observations has allowed us to detect well-defined bumps in the optical LCs, as well as a change in colour, that are indicative of light coming from a core-collapse SN. The accompanying SNe for both events are individually compared with SN1998bw, a known GRB-supernova, and SN1994I, a typical type Ic supernova without a known GRB counterpart, and in both cases the brightness and temporal evolution more closely resemble SN1998bw. We also exploit our extensive optical and radio data for GRB 090618, as well as the publicly-available SWIFT -XRT data, and discuss the properties of the afterglow at early t...

  12. AstroSat CZT Imager observations of GRB 151006A: timing, spectroscopy, and polarisation study

    CERN Document Server

    Rao, A R; Hingar, M K; Iyyani, S; Khanna, Rakesh; Kutty, A P K; Malkar, J P; Paul, D; Bhalerao, V B; Bhattacharya, D; Dewangan, G C; Pawar, Pramod; Vibhute, A M; Chattopadhyay, T; Mithun, N P S; Vadawale, S V; Vagshette, N; Basak, R; Pradeep, P; Samuel, Essy; Sreekumar, S; Vinod, P; Navalgund, K H; Pandiyan, R; Sarma, K S; Seetha, S; Subbarao, K

    2016-01-01

    AstroSat is a multi-wavelength satellite launched on 2015 September 28. The CZT Imager of AstroSat on its very first day of operation detected a long duration gamma-ray burst (GRB) namely GRB 151006A. Using the off-axis imaging and spectral response of the instrument, we demonstrate that CZT Imager can localise this GRB correct to about a few degrees and it can provide, in conjunction with Swift, spectral parameters similar to that obtained from Fermi/GBM. Hence CZT Imager would be a useful addition to the currently operating GRB instruments (Swift and Fermi). Specifically, we argue that the CZT Imager will be most useful for the short hard GRBs by providing localisation for those detected by Fermi and spectral information for those detected only by Swift. We also provide preliminary results on a new exciting capability of this instrument: CZT Imager is able to identify Compton scattered events thereby providing polarisation information for bright GRBs. GRB 151006A, in spite of being relatively faint, shows h...

  13. Concluding Remarks: The Current Status and Future Prospects for GRB Astronomy

    Science.gov (United States)

    Gehrels, Neil

    2009-01-01

    We are in a remarkable period of discovery in GRB astronomy. The current satellites including Swift, Fermi. AGILE and INTEGRAL are detecting and observing bursts of all varieties. Increasing capabilities for follow-up observations on the ground and in space are leading to rapid and deep coverage across the electromagnetic spectrum, The future will see continued operation of the current experiments and with future missions like SVOM plus possible rni_Ssions like JANUS and EXIST. An exciting expansion of capabilities is occurring in areas of gravitational waves and neutrinos that could open new windows on the GRB phenomenon. Increased IR capabilities on the ground and with missions like JWST will enable further exploration of high redshift bursts. The future is bright.

  14. Radio and Optical Follow-Up Observations and Improved IPN Position of GRB 970111

    Science.gov (United States)

    Galama, T. J.; Groot, P. J.; Strom, R. G.; vanParadijs, J.; Hurley, K.; Kouveliotou, C.; Fishman, G. J.; Meegan, C. A.; Heise, J.; intZand, J. J. M.

    1997-01-01

    We report on Westerbork 840 MHz, 1.4 and 5 GHz radio observations of the improved IPN-WFC error box of the gamma ray burst GRB 970111, between 26.4 hours and 120 days after the event onset. In the approximately 16 sq arcmin area defined by the IPN (BATSE and Ulysses) annulus and the published refined BeppoSAX Wide Field Camera (WFC) error box we detected no steady sources brighter than 0.56 mJy (4sigma), and no varying radio emission, down to 1.0 mJy (4sigma). We also report on B, V, R and I band observations of the error box with the 4.2 m William Herschel Telescope at La Palma. Subject headings: gamma rays: bursts - gamma rays: individual (GRB 9701 1 1)

  15. Hubble space telescope observations of the afterglow, supernova, and host galaxy associated with the extremely bright GRB 130427A

    Energy Technology Data Exchange (ETDEWEB)

    Levan, A. J. [Department of Physics, University of Warwick, Coventry, CV4 7AL (United Kingdom); Tanvir, N. R.; Wiersema, K. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH (United Kingdom); Fruchter, A. S.; Hounsell, R. A.; Graham, J. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Hjorth, J.; Fynbo, J. P. U. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Pian, E. [INAF, Trieste Astronomical Observatory, via G.B. Tiepolo 11, I-34143 Trieste (Italy); Mazzali, P. [Astrophysics Research Institute, Liverpool John Moores University, IC2 Liverpool Science Park 146 Brownlow Hill, Liverpool L3 5RF (United Kingdom); Perley, D. A. [Department of Astronomy, California Institute of Technology, MC 249-17, 1200 East California Blvd., Pasadena, CA 91125 (United States); Cano, Z. [Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Dunhagi 5, 107 Reykjavik (Iceland); Cenko, S. B. [Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771 (United States); Kouveliotou, C. [Science and Technology Office, ZP12, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Pe' er, A. [Department of Physics, University College Cork, Cork (Ireland); Misra, K., E-mail: a.j.levan@warwick.ac.uk [Aryabhatta Research Institute of Observational Sciences, Manora Peak, Nainital-263 002 (India)

    2014-09-10

    We present Hubble Space Telescope (HST) observations of the exceptionally bright and luminous Swift gamma-ray burst (GRB), GRB 130427A. At z = 0.34, this burst affords an excellent opportunity to study the supernova (SN) and host galaxy associated with an intrinsically extremely luminous burst (E {sub iso} > 10{sup 54} erg): more luminous than any previous GRB with a spectroscopically associated SN. We use the combination of the image quality, UV capability, and invariant point-spread function of HST to provide the best possible separation of the afterglow, host, and SN contributions to the observed light ∼17 rest-frame days after the burst, utilizing a host subtraction spectrum obtained one year later. Advanced Camera for Surveys grism observations show that the associated SN, SN 2013cq, has an overall spectral shape and luminosity similar to SN 1998bw (with a photospheric velocity, v {sub ph} ∼ 15, 000 km s{sup –1}). The positions of the bluer features are better matched by the higher velocity SN 2010bh (v {sub ph} ∼ 30, 000 km s{sup –1}), but this SN is significantly fainter and fails to reproduce the overall spectral shape, perhaps indicative of velocity structure in the ejecta. We find that the burst originated ∼4 kpc from the nucleus of a moderately star forming (1 M {sub ☉} yr{sup –1}), possibly interacting disk galaxy. The absolute magnitude, physical size, and morphology of this galaxy, as well as the location of the GRB within it, are also strikingly similar to those of GRB 980425/SN 1998bw. The similarity of the SNe and environment from both the most luminous and least luminous GRBs suggests that broadly similar progenitor stars can create GRBs across six orders of magnitude in isotropic energy.

  16. Hubble space telescope observations of the afterglow, supernova, and host galaxy associated with the extremely bright GRB 130427A

    International Nuclear Information System (INIS)

    We present Hubble Space Telescope (HST) observations of the exceptionally bright and luminous Swift gamma-ray burst (GRB), GRB 130427A. At z = 0.34, this burst affords an excellent opportunity to study the supernova (SN) and host galaxy associated with an intrinsically extremely luminous burst (E iso > 1054 erg): more luminous than any previous GRB with a spectroscopically associated SN. We use the combination of the image quality, UV capability, and invariant point-spread function of HST to provide the best possible separation of the afterglow, host, and SN contributions to the observed light ∼17 rest-frame days after the burst, utilizing a host subtraction spectrum obtained one year later. Advanced Camera for Surveys grism observations show that the associated SN, SN 2013cq, has an overall spectral shape and luminosity similar to SN 1998bw (with a photospheric velocity, v ph ∼ 15, 000 km s–1). The positions of the bluer features are better matched by the higher velocity SN 2010bh (v ph ∼ 30, 000 km s–1), but this SN is significantly fainter and fails to reproduce the overall spectral shape, perhaps indicative of velocity structure in the ejecta. We find that the burst originated ∼4 kpc from the nucleus of a moderately star forming (1 M ☉ yr–1), possibly interacting disk galaxy. The absolute magnitude, physical size, and morphology of this galaxy, as well as the location of the GRB within it, are also strikingly similar to those of GRB 980425/SN 1998bw. The similarity of the SNe and environment from both the most luminous and least luminous GRBs suggests that broadly similar progenitor stars can create GRBs across six orders of magnitude in isotropic energy.

  17. MIRAX sensitivity for Gamma Ray Bursts

    Science.gov (United States)

    Sacahui, J. R.; Penacchioni, A. V.; Braga, J.; Castro, M. A.; D'Amico, F.

    2016-03-01

    In this work we present the detection capability of the MIRAX (Monitor e Imageador de RAios-X) experiment for Gamma-Ray Bursts (GRBs). MIRAX is an X-ray astronomy mission designed to perform a wide band hard X-ray (10-200 keV) survey of the sky, especially in the Galactic plane. With a total detection area of 169 cm2, large field of view (FoV, 20 ° × 20 °), angular resolution of 1°45‧ and good spectral and time resolution (∼8% at 60 keV, 10 μs), MIRAX will be optimized for the detection and study of transient sources, such as accreting neutron stars (NS), black holes (BH), Active Galactic Nuclei (AGNs), and both short and long GRBs. This is especially important because MIRAX is expected to operate in an epoch when probably no other hard X-ray wide-field imager will be active. We have performed detailed simulations of MIRAX GRB observations using the GEANT4 package, including the background spectrum and images of GRB sources in order to provide accurate predictions of the sensitivity for the expected GRB rate to be observed. MIRAX will be capable of detecting ∼44 GRBs per year up to redshifts of ∼4.5. The MIRAX mission will be able to contribute significantly to GRB science by detecting a large number of GRBs per year with wide band spectral response. The observations will contribute mainly to the part of GRB spectra where a thermal emission is predicted by the Fireball model. We also discuss the possibility of detecting GRB afterglows in the X-ray band with MIRAX.

  18. Very High Energy Observations of Gamma-Ray Burst Locations with the Whipple Telescope

    CERN Document Server

    Horan, D; Badran, H M; Blaylock, G; Bradbury, S M; Buckley, J H; Byrum, K L; Celik, O; Chow, Y C K; Cogan, P; Cui, W; Daniel, M K; Perez, I de la Calle; Dowdall, C; Falcone, A D; Fegan, D J; Fegan, S J; Finley, J P; Fortin, P; Fortson, L F; Gillanders, G H; Grube, J; Gutíerrez, K J; Hall, J; Hanna, D; Holder, J; Hughes, S B; Humensky, T B; Kenny, G E; Kertzman, M; Kieda, D B; Kildea, J; Krawczynski, H; Krennrich, F; Lang, M J; Le Bohec, S; Maier, G; Moriarty, P; Nagai, T; Ong, R A; Perkins, J S; Petry, D; Quinn, J; Quinn, M; Ragan, K; Reynolds, P T; Rose, H J; Schroedter, M; Sembroski, G H; Steele, D; Swordy, S P; Toner, J A; Valcarcel, L; Vasilev, V V; Wagner, R G; Wakely, S P; Weekes, T C; White, R J; Williams, D A; 10.1086/509567

    2008-01-01

    Gamma-ray burst (GRB) observations at very high energies (VHE, E > 100 GeV) can impose tight constraints on some GRB emission models. Many GRB afterglow models predict a VHE component similar to that seen in blazars and plerions, in which the GRB spectral energy distribution has a double-peaked shape extending into the VHE regime. VHE emission coincident with delayed X-ray flare emission has also been predicted. GRB follow-up observations have had high priority in the observing program at the Whipple 10m Gamma-ray Telescope and GRBs will continue to be high priority targets as the next generation observatory, VERITAS, comes on-line. Upper limits on the VHE emission, at late times (>~4 hours), from seven GRBs observed with the Whipple Telescope are reported here.

  19. Very High Energy Observations of Gamma Ray Bursts with the Whipple/VERITAS Telescopes

    International Nuclear Information System (INIS)

    Gamma-ray Burst (GRB) observations at Very High Energies (VHE, E > 100 GeV) can impose tight constraints on some GRB emission models. Many GRB after-glow models predict a VHE component similar to that seen in blazars and supernova remnants, in which the GRB spectral energy distribution has a double-peaked shape extending into the VHE regime. Consistent with this afterglow scenario, EGRET detected delayed high energy emission from all five bright BATSE GRBs that occurred within its field of view. GRB observations have had high priority in the observing program at the Whipple 10m Telescope and will continue to be high priority targets when the next generation observatory VERITAS comes online. Upper limits on the VHE emission from ten GRBs observed with the Whipple Telescope are reported here

  20. Gamma ray bursts of black hole universe

    Science.gov (United States)

    Zhang, T. X.

    2015-07-01

    Slightly modifying the standard big bang theory, Zhang recently developed a new cosmological model called black hole universe, which has only a single postulate but is consistent with Mach's principle, governed by Einstein's general theory of relativity, and able to explain existing observations of the universe. In the previous studies, we have explained the origin, structure, evolution, expansion, cosmic microwave background radiation, quasar, and acceleration of black hole universe, which grew from a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present state with hundred billion-trillions of solar masses by accreting ambient matter and merging with other black holes. This study investigates gamma ray bursts of black hole universe and provides an alternative explanation for the energy and spectrum measurements of gamma ray bursts according to the black hole universe model. The results indicate that gamma ray bursts can be understood as emissions of dynamic star-like black holes. A black hole, when it accretes its star or merges with another black hole, becomes dynamic. A dynamic black hole has a broken event horizon and thus cannot hold the inside hot (or high-frequency) blackbody radiation, which flows or leaks out and produces a GRB. A star when it collapses into its core black hole produces a long GRB and releases the gravitational potential energy of the star as gamma rays. A black hole that merges with another black hole produces a short GRB and releases a part of their blackbody radiation as gamma rays. The amount of energy obtained from the emissions of dynamic star-like black holes are consistent with the measurements of energy from GRBs. The GRB energy spectra derived from this new emission mechanism are also consistent with the measurements.

  1. The ultra-long GRB 111209A. II. Prompt to afterglow and afterglow properties

    International Nuclear Information System (INIS)

    The 'ultra-long' gamma-ray burst GRB 111209A at redshift z = 0.677 is the longest GRB ever observed thus far, with a rest frame prompt emission duration of ∼4 hr. In order to explain the burst exceptional longevity, a low-metallicity blue supergiant progenitor was invoked. In this article we further constrain the phenomenology and progenitor properties of this peculiar GRB by performing a multiband temporal and spectral analysis of both the prompt and the afterglow emission. We use proprietary and publicly available data from Swift, Konus WIND, XMM-Newton, and TAROT, as well as from other ground-based optical and radio telescopes. We find some peculiar properties that are possibly connected to the exceptional nature of this burst, namely: (1) an unprecedented large optical delay of 410 ± 50 s between the peak time in gamma-rays and the peak time in the optical of a marked multiwavelength flare; (2) multiwavelength prompt emission spectral modeling requires a certain amount of dust in the circumburst environment. The dust produces a rest frame visual extinction of AV = 0.3-1.5 mag, and may undergo destruction at late times; and (3) we detect the presence of a hard spectral extra power-law component at the end of the X-ray steep steep decay phase and before the start of the X-ray afterglow, which has never been revealed thus far in past GRBs. The optical afterglow shows more usual properties; it has a flux power-law decay with an index of 1.6 ± 0.1 and a late rebrightening feature observed at ∼1.1 the day after the first Burst Alert Telescope trigger. We discuss our findings in the context of several possible interpretations that have been given thus far of the complex multiband GRB phenomenology and propose a binary channel formation for the blue supergiant progenitor.

  2. VizieR Online Data Catalog: GRB 091018 Optical/NIR photometry (Wiersema+, 2012)

    Science.gov (United States)

    Wiersema, K.; Curran, P. A.; Kruhler, T.; Melandri, A.; Rol, E.; Starling, R. L. C.; Tanvir, N. R.; van der Horst, A. J.; Covino, S.; Fynbo, J. P. U.; Goldoni, P.; Gorosabel, J.; Hjorth, J.; Klose, S.; Mundell, C. G.; O'Brien, P. T.; Palazzi, E.; Wijers, R. A. M. J.; D'Elia, V.; Evans, P. A.; Filgas, R.; Gomboc, A.; Greiner, J.; Guidorzi, C.; Kaper, L.; Kobayashi, S.; Kouveliotou, C.; Levan, A. J.; Rossi, A.; Rowlinson, A.; Steele, I. A.; de Ugarte Postigo, A.; Vergani, S. D.

    2013-04-01

    GRB 091018 triggered the Burst Alert Telescope (BAT) on board the Swift satellite at 20:48:19 ut on 2009 October 18 (trigger 373172; Stamatikos et al., 2009GCN.10034....1S). We acquired imaging polarimetry using the Focal Reducer and low dispersion Spectrograph (FORS2) mounted on Unit Telescope 1 (Antu) of the VLT, using the FORS2 Rspecial filter. (1 data file).

  3. The GRB All-sky Spectrometer Experiment III: Upgrades and Commissioning

    Science.gov (United States)

    Banks, Zachary; Martinot, Zachary; Voigt, Elana; Pober, Jonathan; Morales, Miguel F.

    2015-01-01

    The GRB All-sky Spectrometer Experiment (GASE) is designed to detect low frequency radio emission following a gamma ray burst. GASE currently uses 8 dipole antennas to detect these emissions. This poster will discuss the commissioning and associated troubleshooting of setting up these antennas. This will include the challenges presented by having the instrument located here in Seattle such as water damage, corrosion, and RFI.

  4. The observable effects of a photospheric component on GRB's and XRF's prompt emission spectrum

    OpenAIRE

    Pe'er, Asaf; Mészáros, Peter; Rees, Martin J.

    2005-01-01

    A thermal radiative component is likely to accompany the first stages of the prompt emission of Gamma-ray bursts (GRB's) and X-ray flashes (XRF's). We analyze the effect of such a component on the observable spectrum, assuming that the observable effects are due to a dissipation process occurring below or near the thermal photosphere. We consider both the internal shock model and a 'slow heating' model as possible dissipation mechanisms. For comparable energy densities in the thermal and the ...

  5. Important Property of GRB Pulse: Power-Law Indices of Time Properties on Energy

    Indian Academy of Sciences (India)

    Zhao-Yang Peng

    2014-09-01

    The dependence of pulse temporal properties (pulse width, pulse rise width and pulse decay width) on energy is power-law function. Some correlated relationships between the power-law indices of the pulse time properties on energy and the spectral lags, relative spectral lags, spectral parameters of band function, and photon flux using a well-separated long-duration -ray burst (GRB) pulse sample is demonstrated here. We argue that the curvature effect can explain the correlated properties.

  6. A Possible Explanation of the Radio Afterglow of GRB980519: The Dense Medium Effect

    OpenAIRE

    X. Y. Wang; Dai, Z. G.; Lu, T.

    1999-01-01

    GRB{980519} is characterized by its rapidly declining optical and X-ray afterglows. Explanations of this behavior include models invoking a dense medium environment which makes the shock wave evolve quickly into the sub-relativistic phase, a jet-like outflow, and a wind-shaped circumburst medium environment. Recently, Frail {et al}. (1999a) found that the latter two cases are consistent with the radio afterglow of this burst. Here, by considering the trans-relativistic shock hydrodynamics, we...

  7. The ultra-long GRB 111209A. II. Prompt to afterglow and afterglow properties

    Energy Technology Data Exchange (ETDEWEB)

    Stratta, G. [Osservatorio Astronomico di Roma (OAR/INAF), via Frascati 33, I-00040 Monte Porzio Catone (Italy); Gendre, B.; Boër, M. [ARTEMIS, UMR 7250 (CNRS/OCA/UNS), boulevard de l' Observatoire, BP 4229, F-06304 Nice Cedex (France); Atteia, J. L. [Université de Toulouse, UPS-OMP, IRAP, F-31400 Toulouse (France); Coward, D. M.; Howell, E. [School of Physics, University of Western Australia (UWA), Crawley, WA 6009 (Australia); De Pasquale, M.; Oates, S. [Mullard Space Science Laboratory (MSSL), University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom); Klotz, A. [IRAP, 14, avenue Edouard Belin, F-31400 Toulouse (France); Piro, L. [Istituto di Astrofisica e Planetologia Spaziali di Roma (IAPS/INAF), via fosso del cavaliere 100, I-00133 Roma (Italy)

    2013-12-10

    The 'ultra-long' gamma-ray burst GRB 111209A at redshift z = 0.677 is the longest GRB ever observed thus far, with a rest frame prompt emission duration of ∼4 hr. In order to explain the burst exceptional longevity, a low-metallicity blue supergiant progenitor was invoked. In this article we further constrain the phenomenology and progenitor properties of this peculiar GRB by performing a multiband temporal and spectral analysis of both the prompt and the afterglow emission. We use proprietary and publicly available data from Swift, Konus WIND, XMM-Newton, and TAROT, as well as from other ground-based optical and radio telescopes. We find some peculiar properties that are possibly connected to the exceptional nature of this burst, namely: (1) an unprecedented large optical delay of 410 ± 50 s between the peak time in gamma-rays and the peak time in the optical of a marked multiwavelength flare; (2) multiwavelength prompt emission spectral modeling requires a certain amount of dust in the circumburst environment. The dust produces a rest frame visual extinction of A{sub V} = 0.3-1.5 mag, and may undergo destruction at late times; and (3) we detect the presence of a hard spectral extra power-law component at the end of the X-ray steep steep decay phase and before the start of the X-ray afterglow, which has never been revealed thus far in past GRBs. The optical afterglow shows more usual properties; it has a flux power-law decay with an index of 1.6 ± 0.1 and a late rebrightening feature observed at ∼1.1 the day after the first Burst Alert Telescope trigger. We discuss our findings in the context of several possible interpretations that have been given thus far of the complex multiband GRB phenomenology and propose a binary channel formation for the blue supergiant progenitor.

  8. ARE ULTRA-LONG GAMMA-RAY BURSTS DIFFERENT?

    International Nuclear Information System (INIS)

    The discovery of a number of gamma-ray bursts (GRBs) with duration exceeding 1000 s has opened the debate on whether these bursts form a new class of sources, the so-called ultra-long GRBs, or if they are rather the tail of the distribution of the standard long GRB duration. Using the long GRB sample detected by Swift, we investigate the statistical properties of long GRBs and compare them with the ultra-long burst properties. We compute the burst duration of long GRBs using the start epoch of the so-called ''steep decay'' phase detected with Swift/XRT. We discuss also the differences observed in their spectral properties. We find that ultra-long GRBs are statistically different from the standard long GRBs with typical burst duration less than 100-500 s, for which a Wolf-Rayet star progenitor is usually invoked. Together with the presence of a thermal emission component we interpret this result as indication that the usual long GRB progenitor scenario cannot explain the extreme duration of ultra-long GRBs, their energetics, as well as the mass reservoir and size that can feed the central engine for such a long time

  9. X-ray spectral diagnostics of the immediate environment of GRB 991216

    OpenAIRE

    Ballantyne, D. R.; Ramirez-Ruiz, E.; Lazzati, D.; Piro, L.

    2002-01-01

    The recent report of iron line features in the afterglow of the gamma-ray burst (GRB) 991216 has important implications for the properties of the radiating material and hence the nature of the immediate burst environment. We argue that the putative strong Fe emission line can be attributed to the reflected emission from Thomson-thick matter which is illuminated by a power-law continuum. The ionization parameter of the material (i.e., the flux to density ratio) is around 10^3, resulting in a F...

  10. A New Derivation of GRB Jet Opening Angles from the Prompt Gamma-Ray Emission

    CERN Document Server

    Goldstein, Adam; Briggs, Michael S; van der Horst, Alexander J; McBreen, Sheila; Kouveliotou, Chryssa; Connaughton, Valerie; Paciesas, William S; Meegan, Charles A; Bhat, P N; Bissaldi, Elisabetta; Burgess, J Michael; Chaplin, Vandiver; Diehl, Roland; Fishman, Gerald J; Fitzpatrick, Gerard; Foley, Suzanne; Gibby, Melissa; Giles, Misty; Greiner, Jochen; Gruber, David; Guiriec, Sylvain; von Kienlin, Andreas; Kippen, Marc; Rau, Arne; Tierney, Dave; Wilson-Hodge, Colleen

    2011-01-01

    The jet opening angle of gamma-ray bursts (GRBs) is an important parameter for determining the characteristics of the progenitor, and the information contained in the opening angle gives insight into the relativistic outflow and the total energy that is contained in the burst. Unfortunately, a confident inference of the jet opening angle usually requires broadband measurement of the afterglow of the GRB, from the X-ray down to the radio and from minutes to days after the prompt gamma-ray emission, which may be difficult to obtain. For this reason, very few of all detected GRBs have constrained jet angles. We present an alternative approach to derive jet opening angles from the prompt emission of the GRB, given that the GRB has a measurable Epeak and fluence, and which does not require any afterglow measurements. We present the distribution of derived jet opening angles for the first two years of the Fermi Gamma-ray Burst Monitor (GBM) operation, and we compare a number of our derived opening angles to the rep...

  11. Prompt emission from GRB 150915A in the GeV energy range detected at ground by the New-Tupi detector

    OpenAIRE

    Augusto, C. R. A.; Navia, C. E.; M.N. Oliveira; Nepomuceno, A. A.; Kopenkin, V.; Sinzi, T.

    2016-01-01

    Since 2014, a new detector (New-Tupi) consisting of four plastic scintillators ($150 \\times 75 \\times 5 cm^3$) placed in pairs and located in Niteroi, Rio de Janeiro, Brazil, has been used for the search of transient solar events and photomuons from gamma-ray bursts (GRBs). On September 15, 2015, at 21:18:24 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 150915A (trigger 655721). The GRB light curve shows a weak complex structure of long duration $T_{90}=164.7 \\pm 49.7 $ ...

  12. Gamma-Ray Bursts are Produced Predominately in the Early Universe

    OpenAIRE

    Lin, J. R.; Zhang, S.N.; Li, T. P.

    2003-01-01

    It is known that some observed gamma-ray bursts (GRBs) are produced at cosmological distances and that the GRB production rate may follow the star formation rate. We model the BATSE-detected intensity distribution of long GRBs in order to determine their space density distribution and opening angle distribution. Our main results are: the lower and upper distance limits to the GRB production are z 0.24 and >10, respectively; the GRB opening angle follows an exponential distribution and the mea...

  13. X-ray Spectral Diagnostics of $\\gamma$-Ray Burst Environments

    CERN Document Server

    Paerels, F B S; Heise, J; Liedahl, D A; Paerels, Frits; Kuulkers, Erik; Heise, John; Liedahl, Duane A.

    2000-01-01

    Recently, the detection of discrete features in the X-ray afterglow spectra of GRB970508 and GRB970828 was reported. The most natural interpretation of these features is that they are redshifted Fe K emission complexes. The identification of the line emission mechanism has drastic implications for the inferred mass of radiating material, end hence the nature of the burst site. X-ray spectroscopy provides a direct observational constraint on these properties of gamma-ray bursters. We briefly discuss how these constraints arise, in the context of an application to the spectrum of GRB970508.

  14. The connection between Gamma-ray bursts and Supernovae Ib/c

    OpenAIRE

    Elisabetta Bissaldi; Francesco Calura(); Francesca Matteucci(Dipartimento di Astronomia, Universitá di Trieste); Francesco Longo; Guido Barbiellini()

    2007-01-01

    It has been established that Gamma-Ray Bursts (GRBs) are connected to Supernovae (SNe) explosions of Type Ib/c. We intend to test whether the hypothesis of Type Ib/c SNe from different massive progenitors can reproduce the local GRB rate as well as the GRB rate as a function of redshift. We aim to predict the GRB rate at very high redshift under different assumptions about galaxy formation and star formation histories in galaxies. We assume different star formation histories...

  15. Constraints on the hadronic content of gamma ray bursts

    International Nuclear Information System (INIS)

    The IceCube High-energy Neutrino Telescope has been collecting data since 2006. Conversely, hundreds of gamma-ray bursts (GRBs) have been detected by the GRB Monitor on board Fermi since its launch in 2008. So far no neutrino event has been associated with a GRB, despite many models predicting the generation of high-energy neutrinos through GRB photon interaction with PeV protons in the GRB jet. We use the non-detection of neutrinos to constrain the hadronic content of GRB jets independent of jet model parameters. Assuming a generic particle spectrum of E –α with α = 2, we find that the ratio of the energy carried by pions to that in electrons has to be small f π/fe ≲ 0.24 at 95% confidence level. A distribution of spectral slopes can lower f π/fe by orders of magnitude. Another limit, independent of neutrinos, is obtained if one ascribes the measured Fermi/Large Area Telescope GeV gamma-ray emission to pair-photon cascades of high-energy photons resulting from (the same photon-hadronic interactions and subsequent) neutral pion decays. Based on the generally observed MeV-to-GeV GRB fluence ratio of ≈10, we show that f π/fe ≲ 0.3. In some bursts, this ratio is as low as unity, f π/fe ≲ 0.03. These findings add to mounting doubts regarding the presence of PeV protons in GRB jets.

  16. The Swift Gamma Ray Burst Mission

    Science.gov (United States)

    Gehrels, Neil

    2004-01-01

    Swift is an international mission managed by NASA as part of its MIDEX program. It is a multiwavelength transient observatory for GRB astronomy that will launch in 2004. The goals of the mission are to determine the origin of GRBs and their afterglows and use bursts to probe the early Universe. A wide field gamma-ray camera will detect more than a hundred GRBs per year to 2-5 times fainter than BATSE. Sensitive narrow-field X-ray, and UV/optical telescopes will be pointed at the burst location in 20 to 75 sec by an autonomously controlled 'swift' spacecraft. For each burst, arcsec positions will be determined and optical/UV/x-ray/gamma-ray spectrophotometry performed. Measurements of redshift will be made for many of the bursts. The instrumentation is a combination of superb existing flight-spare hardware and design from XMM and Spectrum-X/JET-X contributed by collaborators in the UK and Italy and development of a coded-aperture camera with a large-area (approx. 0.5 square meter) CdZnTe detector array. The instruments have now completed their fabrication phase and are integrated on the observatory for final testing. Key components of the mission are vigorous follow-up and outreach programs to engage the astronomical community and public in Swift. The talk will describe the mission and its status and give a summary of our plans for GRB operations.

  17. DETECTION OF A SPECTRAL BREAK IN THE EXTRA HARD COMPONENT OF GRB 090926A

    International Nuclear Information System (INIS)

    We report on the observation of the bright, long gamma-ray burst, GRB 090926A, by the Gamma-ray Burst Monitor and Large Area Telescope (LAT) instruments on board the Fermi Gamma-ray Space Telescope. GRB 090926A shares several features with other bright LAT bursts. In particular, it clearly shows a short spike in the light curve that is present in all detectors that see the burst, and this in turn suggests that there is a common region of emission across the entire Fermi energy range. In addition, while a separate high-energy power-law component has already been observed in other gamma-ray bursts, here we report for the first time the detection with good significance of a high-energy spectral break (or cutoff) in this power-law component around 1.4 GeV in the time-integrated spectrum. If the spectral break is caused by opacity to electron-positron pair production within the source, then this observation allows us to compute the bulk Lorentz factor for the outflow, rather than a lower limit.

  18. Observations of the Prompt Gamma-Ray Emission of GRB 070125

    CERN Document Server

    Bellm, Eric C; Pal'shin, Valentin; Yamaoka, Kazutaka; Bandstra, Mark E; Boggs, Steven E; Hong, Soojing; Kodaka, Natsuki; Kozyrev, A S; Litvak, M L; Mitrofanov, I G; Nakagawa, Yujin E; Ohno, Masanori; Onda, Kaori; Sanin, A B; Sugita, Satoshi; Tashiro, Makoto; Tretyakov, V I; Urata, Yuji; Wigger, Claudia

    2007-01-01

    The long, bright gamma-ray burst GRB 070125 was localized by the Interplanetary Network. We present light curves of the prompt gamma-ray emission as observed by Konus-WIND, RHESSI, Suzaku-WAM, and Swift-BAT. We detail the results of joint spectral fits with Konus and RHESSI data. The burst shows moderate hard-to-soft evolution in its multi-peaked emission over a period of about one minute. The total burst fluence as observed by Konus is $1.75 \\times 10^{-4}$ erg/cm$^2$ (20 keV-10 MeV). Using the spectroscopic redshift z = 1.547, we find that the burst is consistent with the Amati $E_{peak,i}-E_{iso}$ and the Ghirlanda $E_{peak,i}-E_\\gamma$ correlations.

  19. The Optical Afterglow of a Short Gamma-ray Burst

    Science.gov (United States)

    Hjorth, Jens; Watson, Darach; Flynbo, Johan P.U.; Price, Paul A.; Jensen, Brian L.; Jorgensen, Uffe G.; Kubas, Daniel; Gorosabel, Javier; Jakobssonk, Pall; Sollerman, Jesper

    2005-01-01

    It has long been known that there are two classes of gamma-ray bursts (GRBs), principally distinguished by their durations. The breakthrough in our understanding of long-duration GRBs (greater than 2 seconds in duration), that ultimately linked them with energetic Type Ic supernovae, came about from the discovery of their long-lived X-ray and optical "afterglow", when precise and rapid localizations of the sources could finally be obtained. Recently, X-ray localizations have become available for short (less than 2 seconds in duration) GRBs, a hitherto elusive GRB population, that has evaded optical detection for more than thirty years. Here we report the discovery of transient optical emission (R approximately 23 mag) associated with a short GRB. This first short GRB afterglow is localized with sub-arcsecond accuracy onto the outskirts of a blue dwarf galaxy. Unless the optical and X-ray afterglow arise from different mechanisms our observations 33 h after the GRB suggest that, analogously to long GRBs, we observe synchrotron emission from ultrarelativistic ejecta (ZZZ CAN WE LIMIT GAMMA?). In contrast, we did not detect a bright supernova, as found in most nearby long GRB afterglows, which suggests a different origidstrongly constrain the nature of the short GRB progenitors.

  20. Evidence for a Photospheric Component in the Prompt Emission of the Short GRB120323A and its Effects on the GRB Hardness-Luminosity Relation

    CERN Document Server

    Guiriec, S; Hascoët, R; Vianello, G; Mochkovitch, R; Ryde, F; Kouveliotou, C; Xiong, S; Bhat, P N; Foley, S; Grüber, D; Burgess, J M; McGlynn, S; McEnery, J; Gehrels, N

    2012-01-01

    The short GRB 120323A had the highest flux ever detected with the Fermi/GBM. Here we study its remarkable spectral properties and their evolution using two spectral models: (i) a single emission component scenario, where the spectrum is modeled by the empirical Band function, and (ii) a two component scenario, where thermal (Planck-like) emission is observed simultaneously with a non-thermal component (a Band function). We find that the latter model fits the integrated burst spectrum significantly better than the former, and that their respective spectral parameters are dramatically different: when fit with a Band function only, the Epeak of the event is unusually soft for a short GRB, while adding a thermal component leads to more typical short GRB values. Our time-resolved spectral analysis produces similar results. We argue here that the two-component model is the preferred interpretation for GRB 120323A, based on: (i) the values and evolution of the Band function parameters of the two component scenario, ...

  1. CONSTRAINING THE BULK LORENTZ FACTOR OF GAMMA-RAY BURST OUTFLOW IN THE MAGNETIC-DOMINATED JET MODEL

    Energy Technology Data Exchange (ETDEWEB)

    Chang Zhe; Lin Hainan; Jiang Yunguo, E-mail: changz@ihep.ac.cn, E-mail: linhn@ihep.ac.cn, E-mail: jiangyg@ihep.ac.cn [Institute of High Energy Physics, Chinese Academy of Sciences, 100049 Beijing (China)

    2012-11-10

    Recent observations by the Fermi-LAT showed that there are delayed arrivals of GeV photons relative to the onset of MeV photons in some gamma-ray bursts (GRBs). In order to avoid a large optical depth, the minimal value of the Lorentz factor has been estimated to be higher than 1000 in some of the brightest bursts. In this paper, we present a detailed calculation of the time delay between the MeV and GeV photons in the framework of the magnetic-dominated jet model. We find that the time delay strongly depends on the saturated bulk Lorentz factor of the jet. Inspired by this fact, we use this model to calculate the Lorentz factors of the four brightest Fermi bursts. The results indicate that the Lorentz factors are much smaller than those obtained from the 'single-zone' scenario. The short burst GRB 090510 has a minimal Lorentz factor of 385, while the three long bursts, GRB 080916c, GRB 090902b, and GRB 090926, have almost the same Lorentz factors with an average value near 260. Another interesting result is that, for long bursts, GeV photons are emitted after the bulk Lorentz factor saturates. For the short GRB, however, MeV and GeV photons are emitted at the same phase, i.e., either in the expansion phase or in the coasting phase.

  2. THE LONG AND THE SHORT OF THE HIGH-ENERGY EMISSION IN GRB090926A: AN EXTERNAL SHOCK

    International Nuclear Information System (INIS)

    Synchrotron self-Compton (SSC) emission from a reverse shock has been suggested as the origin for the high-energy component lasting 2 s in the prompt phase of GRB98080923. The model describes spectral indices, fluxes, and the duration of the high-energy component as well as a long keV tail present in the prompt phase of GRB980923. Here, we present an extension of this model to describe the high-energy emission of GRB090926A. We argue that the emission consists of two components, one with a duration less than 1 s during the prompt phase, and a second, longer-lasting GeV phase lasting hundred of seconds after the prompt phase. The short high-energy phase can be described as SSC emission from a reverse shock similar to that observed in GRB980923, while the longer component arises from the forward shock. The main assumption is that the jet is magnetized and evolves in the thick-shell case, and the calculated fluxes and break energies are all consistent with the observed values. A comparison between the resulting parameters obtained for GRB980923 and GRB090926A suggests differences in burst tails that could be attributable to the circumburst medium, and this could account for previous analyses reported in the literature for other bursts. We find that the density of the surrounding medium inferred from the observed values associated with the forward shock agrees with standard values for host galaxies such as the one associated with GRB090926A.

  3. The ultraluminous GRB 110918A

    CERN Document Server

    Frederiks, D D; Svinkin, D S; Pal'shin, V D; Mangano, V; Oates, S; Aptekar, R L; Golenetskii, S V; Mazets, E P; Oleynik, Ph P; Tsvetkova, A E; Ulanov, M V; Kokomov, A V; Cline, T L; Burrows, D N; Krimm, H A; Pagani, C; Sbarufatti, B; Siegel, M H; Mitrofanov, I G; Golovin, D; Litvak, M L; Sanin, A B; Boynton, W; Fellows, C; Harshman, K; Enos, H; Starr, R; von Kienlin, A; Rau, A; Zhang, X; Goldstein, J

    2013-01-01

    GRB 110918A is the brightest long GRB detected by Konus-WIND during its 19 years of continuous observations and the most luminous GRB ever observed since the beginning of the cosmological era in 1997. We report on the final IPN localization of this event and its detailed multiwavelength study with a number of space-based instruments. The prompt emission is characterized by a typical duration, a moderare $E_{peak}$ of the time-integrated spectrum, and strong hard-to-soft evolution. The high observed energy fluence yields, at z=0.984, a huge isotropic-equivalent energy release $E_{iso}=(2.1\\pm0.1)\\times10^{54}$ erg. The record-breaking energy flux observed at the peak of the short, bright, hard initial pulse results in an unprecedented isotropic-equivalent luminosity $L_{iso}=(4.7\\pm0.2)\\times10^{54}$erg s$^{-1}$. A tail of the soft gamma-ray emission was detected with temporal and spectral behavior typical of that predicted by the synchrotron forward-shock model. Swift/XRT and Swift/UVOT observed the bright af...

  4. Search for gamma-rays from the unusually bright GRB 130427A with the HAWC Gamma-ray Observatory

    CERN Document Server

    Abeysekara, A U; Alvarez, C; Arceo, R; Arteaga-Velázquez, J C; Solares, H A Ayala; Barber, A S; Baughman, B M; Bautista-Elivar, N; BenZvi, S Y; Rosales, M Bonilla; Braun, J; Caballero-Mora, K S; Carramiñana, A; Castillo, M; Cotti, U; Cotzomi, J; de la Fuente, E; De León, C; DeYoung, T; Hernandez, R Diaz; Dingus, B L; DuVernois, M A; Ellsworth, R W; Fiorino, D W; Fraija, N; Galindo, A; González, M M; Goodman, J A; Gussert, M; Hampel-Arias, Z; Harding, J P; Hui, C M; Hüntemeyer, P; Imran, A; Iriarte, A; Karn, P; Kieda, D; Kunde, G J; Lara, A; Lauer, R J; Lee, W H; Lennarz, D; Vargas, H León; Linnemann, J T; Longo, M; Luna-García, R; Malone, K; Marinelli, A; Marinelli, S S; Martinez, H; Martinez, O; Martínez-Castro, J; Matthews, J A J; Torres, E Mendoza; Miranda-Romagnoli, P; Moreno, E; Mostafá, M; Nellen, L; Newbold, M; Noriega-Papaqui, R; Oceguera-Becerra, T O; Patricelli, B; Pelayo, R; Ponce, E; Pretz, J; Pérez-Pérez, E G; Rivière, C; Rosa-González, D; Salazar, H; Greus, F Salesa; Sandoval, A; Schneider, M; Sinnis, G; Smith, A J; Woodle, K Sparks; Springer, R W; Taboada, I; Tollefson, K; Torres, I; Ukwatta, T N; Villaseñor, L; Weisgarber, T; Westerhoff, S; Wisher, I G; Wood, J; Yodh, G B; Younk, P W; Zaborov, D; Zepeda, A; Zhou, H; Álvarez, J D

    2014-01-01

    The long gamma-ray burst (GRB) 130427A was the most powerful burst ever detected with a redshift $z\\lesssim0.5$, featuring the highest energy photon so far detected from a GRB and the longest lasting emission above 100 MeV. The HAWC Gamma-ray Observatory is a new extensive air shower detector currently under construction in central Mexico. It features two data acquisition (DAQ) systems - one designed to readout full air-shower events (main DAQ) and the other one counting the signals in each photomultiplier tube (scaler DAQ). The burst occurred at a zenith angle of $57^\\circ$, when HAWC was running 10% of the final detector and collecting data with the scaler DAQ only. Based on the observed light curve at MeV-GeV energies, 8 different time periods have been searched for prompt and delayed emission from this GRB. In all cases, no statistically significant excess of counts has been found and upper limits have been placed. It is shown that a similar GRB close to zenith would be easily detected by the full HAWC de...

  5. Probing Massive Stars Around Gamma-Ray Burst Progenitors

    OpenAIRE

    Lu, Wenbin; Kumar, Pawan; Smoot, George F.

    2015-01-01

    Long Gamma-Ray Bursts (GRBs) are produced by ultra-relativistic jets launched from core collapse of massive stars. Most massive stars form in binaries and/or in star clusters, which means that there may be a significant external photon field (EPF) around the GRB progenitor. We calculate the inverse-Compton scattering of EPF by the hot electrons in the GRB jet. Three possible cases of EPFs are considered: the progenitor is (I) in a massive binary system, (II) surrounded by a Wolf-Rayet-star wi...

  6. Delayed Flash from Counter Jet of Gamma Ray Burst

    CERN Document Server

    Yamazaki, R; Nakamura, T; Yamazaki, Ryo; Ioka, Kunihito; Nakamura, Takashi

    2003-01-01

    If the X-ray flash is the gamma ray burst (GRB) observed with the large viewing angle from the forward jet, we show that the emission from the counter jet should be observed as the delayed flash in the UV or optical band several hours to a day after the X-ray flash. If the distance is several tens of Mpc or so, i.e., similar to GRB980425, FUV-MAMA on HST/STIS or UVOT on Swift can observe the delayed flash, so that the collimated jets of the GRBs may be directly confirmed.

  7. Dust-to-metal ratios in Damped Lyman-alpha absorbers: Fresh clues to the origins of dust and optical extinction towards gamma-ray bursts

    CERN Document Server

    De Cia, A; Savaglio, S; Schady, P; Vreeswijk, P M

    2013-01-01

    Motivated by the anomalous dust-to-metal ratios (DTM) derived in the literature for gamma-ray burst (GRB) damped Ly-alpha absorbers (DLAs), we measure these ratios using the dust-depletion pattern observed in UV/optical afterglow spectra, associated with the interstellar medium (ISM) at the GRB host-galaxy redshifts. Our sample consists of 20 GRB absorbers and a comparison sample of 72 QSO-DLAs, overall at redshift 1.2 14.7, above which several QSO-DLAs reveal H2, making GRB-DLAs promising candidates for molecular research.

  8. The afterglow of GRB 130427A from 1 to 1016 GHz

    International Nuclear Information System (INIS)

    We present multiwavelength observations of the afterglow of GRB 130427A, the brightest (in total fluence) gamma-ray burst (GRB) of the past 29 yr. Optical spectroscopy from Gemini-North reveals the redshift of the GRB to be z = 0.340, indicating that its unprecedented brightness is primarily the result of its relatively close proximity to Earth; the intrinsic luminosities of both the GRB and its afterglow are not extreme in comparison to other bright GRBs. We present a large suite of multiwavelength observations spanning from 300 s to 130 days after the burst and demonstrate that the afterglow shows relatively simple, smooth evolution at all frequencies, with no significant late-time flaring or rebrightening activity. The entire data set from 1 GHz to 10 GeV can be modeled as synchrotron emission from a combination of reverse and forward shocks in good agreement with the standard afterglow model, providing strong support to the applicability of the underlying theory and clarifying the nature of the GeV emission observed to last for minutes to hours following other very bright GRBs. A tenuous, wind-stratified circumburst density profile is required by the observations, suggesting a massive-star progenitor with a low mass-loss rate, perhaps due to low metallicity. GRBs similar in nature to GRB 130427A, inhabiting low-density media and exhibiting strong reverse shocks, are probably not uncommon but may have been difficult to recognize in the past owing to their relatively faint late-time radio emission; more such events should be found in abundance by the new generation of sensitive radio and millimeter instruments.

  9. The afterglow of GRB 130427A from 1 to 10{sup 16} GHz

    Energy Technology Data Exchange (ETDEWEB)

    Perley, D. A. [Department of Astronomy, California Institute of Technology, MC 249-17, 1200 East California Blvd, Pasadena, CA 91125 (United States); Cenko, S. B. [Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771 (United States); Corsi, A. [Physics Department, George Washington University, 725 21st St, NW Washington, DC 20052 (United States); Tanvir, N. R.; Wiersema, K. [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Levan, A. J. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Kann, D. A.; Greiner, J. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße, D-85748 Garching (Germany); Sonbas, E. [Department of Physics, University of Adiyaman, 02040 Adiyaman (Turkey); Zheng, W.; Clubb, K. I. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Zhao, X.-H.; Bai, J.-M.; Chang, L. [Yunnan Observatories, Chinese Academy of Sciences, P.O. Box 110, 650011 Kunming (China); Bremer, M. [Institute de Radioastronomie Millimètrique (IRAM), 300 rue de la Piscine, F-38406 Saint Martin d' Hères (France); Castro-Tirado, A. J. [Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, E-18008 Granada (Spain); Frail, D. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Fruchter, A. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Göğüş, E. [Sabancı University, Orhanlı- Tuzla, İstanbul 34956 (Turkey); Güver, T., E-mail: dperley@astro.caltech.edu [Istanbul University Science Faculty, Department of Astronomy and Space Sciences, 34119, University-Istanbul (Turkey); and others

    2014-01-20

    We present multiwavelength observations of the afterglow of GRB 130427A, the brightest (in total fluence) gamma-ray burst (GRB) of the past 29 yr. Optical spectroscopy from Gemini-North reveals the redshift of the GRB to be z = 0.340, indicating that its unprecedented brightness is primarily the result of its relatively close proximity to Earth; the intrinsic luminosities of both the GRB and its afterglow are not extreme in comparison to other bright GRBs. We present a large suite of multiwavelength observations spanning from 300 s to 130 days after the burst and demonstrate that the afterglow shows relatively simple, smooth evolution at all frequencies, with no significant late-time flaring or rebrightening activity. The entire data set from 1 GHz to 10 GeV can be modeled as synchrotron emission from a combination of reverse and forward shocks in good agreement with the standard afterglow model, providing strong support to the applicability of the underlying theory and clarifying the nature of the GeV emission observed to last for minutes to hours following other very bright GRBs. A tenuous, wind-stratified circumburst density profile is required by the observations, suggesting a massive-star progenitor with a low mass-loss rate, perhaps due to low metallicity. GRBs similar in nature to GRB 130427A, inhabiting low-density media and exhibiting strong reverse shocks, are probably not uncommon but may have been difficult to recognize in the past owing to their relatively faint late-time radio emission; more such events should be found in abundance by the new generation of sensitive radio and millimeter instruments.

  10. Multicolor observations of the afterglow of the short/hard GRB050724

    International Nuclear Information System (INIS)

    Context. New information on short/ hard gamma-ray bursts (GRBs) is being gathered thanks to the discovery of their optical and X-ray afterglows. However, some key aspects are still poorly understood, including the collimation level of the outflow, the duration of the central engine activity, and the properties of the progenitor systems. Aims. We want to constrain the physical properties of the short GRB 050724 and of its host galaxy, and make some inferences on the global short GRB population. Methods. We present optical observations of the afterglow of GRB050724 and of its host galaxy, significantly expanding the existing dataset for this event. We compare our results with models, complementing them with available measurements from the literature. We study the afterglow light curve and spectrum including X-ray data. We also present observations of the host galaxy. Results. The observed optical emission was likely related to the large flare observed in the X-ray light curve. The apparent steep decay was therefore not due to the jet effect. Available data are indeed consistent with low collimation, in turn implying a large energy release, comparable to that of long GRBs. The flare properties also constrain the internal shock mechanism, requiring a large Lorentz factor contrast between the colliding shells. This implies that the central engine was active at late times, rather than ejecting all shells simultaneously. The host galaxy has red colors and no ongoing star formation, consistent with previous findings on this GRB. However, it is not a pure elliptical, and has some faint spiral structure. Conclusions. GRB 050724 provides the most compelling case for association between a short burst and a galaxy with old stellar population. It thus plays a pivotal role in constraining progenitors models, which should allow for long delays between birth and explosion. (authors)

  11. Multicolor observations of the afterglow of the short/hard GRB050724

    Energy Technology Data Exchange (ETDEWEB)

    Malesani, D. [Univ Copenhagen, Niels Bohr Inst, Dark Cosmol Ctr, DK-2100 Copenhagen 0, (Denmark); Covino, S.; D' Avanzo, P.; Fugazza, D.; Campana, S.; Tagliaferri, G.; Chincarini, G.; Guidorzi, C.; Romano, P. [Osser Astron Brera, INAF, I-23807 Merate (Italy); D' Avanzo, P. [Univ Insubria, Dipartimento Matemat and Fis, I-23807 Merate, LC, (Italy); D' Elia, V.; Piranomonte, S.; Stella, L.; Antonelli, L.A.; Israel, G.L.; Melandri, A. [Osserv Astron Roma, INAF, I-00040 Monte Porzio Catone, (Italy); Fugazza, D.; Chincarini, G.; Guidorzi, C.; Romano, P. [Univ Milano Bicocca, Dipartimento Fis, I-20126 Milan, (Italy); Ballo, L. [ESA, European Space Astron Ctr, Madrid 28691, (Spain); Antonelli, L.A.; Stratta, G. [ASI Sci Data Ctr, I-00044 Frascati, (Italy); Della Valle, M. [Osserv Astrofis Arcetri, INAF, I-50125 Florence, (Italy); Della Valle, M. [Univ Calif Santa Barbara, Kavli Inst Theoret Phys, Santa Barbara, CA 93106 (United States); Goldoni, P. [Lab Astrparticule and Cosmol, F-75205 Paris 13, (France); Goldoni, P. [CEA Saclay, DSM, DAPNIA SAp, Serv Astrophys, F-91191 Gif Sur Yvette, (France)] (and others)

    2007-07-01

    Context. New information on short/ hard gamma-ray bursts (GRBs) is being gathered thanks to the discovery of their optical and X-ray afterglows. However, some key aspects are still poorly understood, including the collimation level of the outflow, the duration of the central engine activity, and the properties of the progenitor systems. Aims. We want to constrain the physical properties of the short GRB 050724 and of its host galaxy, and make some inferences on the global short GRB population. Methods. We present optical observations of the afterglow of GRB050724 and of its host galaxy, significantly expanding the existing dataset for this event. We compare our results with models, complementing them with available measurements from the literature. We study the afterglow light curve and spectrum including X-ray data. We also present observations of the host galaxy. Results. The observed optical emission was likely related to the large flare observed in the X-ray light curve. The apparent steep decay was therefore not due to the jet effect. Available data are indeed consistent with low collimation, in turn implying a large energy release, comparable to that of long GRBs. The flare properties also constrain the internal shock mechanism, requiring a large Lorentz factor contrast between the colliding shells. This implies that the central engine was active at late times, rather than ejecting all shells simultaneously. The host galaxy has red colors and no ongoing star formation, consistent with previous findings on this GRB. However, it is not a pure elliptical, and has some faint spiral structure. Conclusions. GRB 050724 provides the most compelling case for association between a short burst and a galaxy with old stellar population. It thus plays a pivotal role in constraining progenitors models, which should allow for long delays between birth and explosion. (authors)

  12. Unveiling the Secrets of Metallicity and Massive Star Formation Using DLAs Along Gamma-Ray Bursts

    Science.gov (United States)

    Cucchiara, A.; Fumagalli, M.; Rafelski, M.; Kocevski, D.; Prochaska, J. X.; Cooke, R. J.; Becker, G. D.

    2015-01-01

    We present the largest, publicly available, sample of Damped Lyman-alpha systems (DLAs) along Swift discovered Gamma-ray Bursts (GRB) line of sights in order to investigate the environmental properties of long GRB hosts in the z = 1.8 - 6 redshift range. Compared with the most recent quasar DLAs sample (QSO-DLA), our analysis shows that GRB-DLAs probe a more metal enriched environment at z approximately greater than 3, up to [X/H] approximately -0.5. In the z = 2 - 3 redshift range, despite the large number of lower limits, there are hints that the two populations may be more similar (only at 90% significance level) than at higher redshifts. Also, at high-z, the GRB-DLA average metallicity seems to decline at a shallower rate than the QSO-DLAs: GRB-DLA hosts may be polluted with metals at least as far as approximately 2 kpc from the GRB explosion site, probably due to previous star-formation episodes and/or supernovae explosions. This shallow metallicity trend, extended now up to z approximately 5, confirms previous results that GRB hosts are star-forming and have, on average, higher metallicity than the general QSO-DLA population. Finally, our host metallicity measurements are broadly consistent with the predictions derived from the hypothesis of two channels of GRB progenitors, one of which is mildly affected by a metallicity bias, although more data are needed to constrain the models at z approximately greater than 4.

  13. A search for \\textit{Fermi} bursts associated to supernovae and their frequency of occurrence

    CERN Document Server

    Kovacevic, M; Wang, Y; Muccino, M; Della Valle, M; Amati, L; Barbarino, C; Enderli, M; Pisani, G B; Li, L

    2014-01-01

    Context: Observations suggest that the major fraction of long duration gamma-ray bursts (GRBs) are connected with broad-lines supernovae Ib/c, (SNe-Ibc). The presence of GRB-SNe is revealed by rebrightenings emerging from the optical GRB afterglow $10$--$15$ days, in the rest-frame of the source, after the prompt GRB emission. Aims: \\textit{Fermi}-GBM has a field of view (FoV) which is about 6.5 times larger than the FoV of \\textit{Swift}, therefore we expect that a number of GRB-SN connections have been missed due to lack of optical and X-ray instruments on board of \\textit{Fermi}, which are essential to reveal SNe associated with GRBs. This fact has motivated our search in the \\textit{Fermi} catalogue for possible GRB-SN events. Methods: The search for possible GRB-SN associations follows two requirements: (1) SN should fall inside the \\textit{Fermi}-GBM error box of the considered long GRB, and (2) this GRB should occur within $20$ days before the SN event. Results: We have found $5$ cases, within $z<0....

  14. Gamma bursts

    International Nuclear Information System (INIS)

    The Vela satellite series has recently detected gamma bursts in the 0.2-1.5MeV energy range. These bursts last an average of from 0.1 to 10s and have a fine time structure, with pulses lasting less than several tens of milliseconds. With simultaneous observations from different satellites it has been possible to determine the spatial origin of some of the bursts. No correlation, however, has been made with known objects. In spite of the fragmentary character of the information received to date, several theories have already been proposed to account for these phenomena

  15. A search for thermal X-ray signatures in gamma-ray bursts - I. Swift bursts with optical supernovae

    Science.gov (United States)

    Starling, R. L. C.; Page, K. L.; Pe'Er, A.; Beardmore, A. P.; Osborne, J. P.

    2012-12-01

    The X-ray spectra of gamma-ray bursts (GRBs) can generally be described by an absorbed power law. The landmark discovery of thermal X-ray emission in addition to the power law in the unusual GRB 060218, followed by a similar discovery in GRB 100316D, showed that during the first thousand seconds after trigger the soft X-ray spectra can be complex. Both the origin and prevalence of such spectral components still evade understanding, particularly after the discovery of thermal X-ray emission in the classical GRB 090618. Possibly most importantly, these three objects are all associated with optical supernovae (SNe), begging the question of whether the thermal X-ray components could be a result of the GRB-SN connection, possibly in the shock breakout. We therefore performed a search for blackbody components in the early Swift X-ray spectra of 11 GRBs that have or may have associated optical SNe, accurately recovering the thermal components reported in the literature for GRBs 060218, 090618 and 100316D. We present the discovery of a cooling blackbody in GRB 101219B/SN2010ma, and in four further GRB-SNe we find an improvement in the fit with a blackbody which we deem possible blackbody candidates due to case-specific caveats. All the possible new blackbody components we report lie at the high end of the luminosity and radius distribution. GRB 101219B appears to bridge the gap between the low-luminosity and the classical GRB-SNe with thermal emission, and following the blackbody evolution we derive an expansion velocity for this source of the order of 0.4c. We discuss potential origins for the thermal X-ray emission in our sample, including a cocoon model which we find can accommodate the more extreme physical parameters implied by many of our model fits.

  16. High Energy Radiation from $\\gamma$ Ray Bursts

    CERN Document Server

    Dermer, C D; Dermer, Charles D.; Chiang, James

    1999-01-01

    Gamma-ray burst (GRB) engines are probed most intimately during the prompt gamma-ray luminous phase when the expanding blast wave is closest to the explosion center. Using GRBs 990123 and 940217 as guides, we briefly review observations of high-energy emission from GRBs and summarize some problems in GRB physics. \\gamma\\gamma transparency arguments imply relativistic beaming. The parameters that go into the external shock model are stated, and we show numerical simulation results of gamma-ray light curves from relativistic blast waves with different amounts of baryon loading. A distinct component due to the synchrotron self-Compton process produces significant emission at GeV and TeV energies. Predictions for spectral and temporal evolution at these energies are presented for a blast wave expanding into uniform surroundings. Observations of the slow decay of GeV-TeV radiation provide evidence for ultra-high energy cosmic ray acceleration in GRBs.

  17. The Second Fermi GBM Gamma-Ray Burst Catalog: The First Four Years

    OpenAIRE

    Kienlin, von, A.; Meegan, C. A.; Paciesas, W. S.; Bhat, P.N.; Bissaldi, E.; Briggs, M S; Burgess, J. M.; Byrne, D.; Chaplin, V.; Cleveland, W.; Connaughton, V.; Collazzi, A.C.; Fitzpatrick, G.; Foley, S.; Gibby, M.

    2014-01-01

    This is the second of a series of catalogs of gamma-ray bursts (GRBs) observed with the Fermi Gamma-ray Burst Monitor (GBM). It extends the first two-year catalog by two more years, resulting in an overall list of 953 GBM triggered GRBs. The intention of the GBM GRB catalog is to provide information to the community on the most important observables of the GBM detected GRBs. For each GRB the location and main characteristics of the prompt emission, the duration, peak flux and fluence are deri...

  18. Open issues in Gamma-Ray Bursts: Polarimetry and dark GRBs

    Energy Technology Data Exchange (ETDEWEB)

    Malesani, D. [SISSA, Trieste (Italy); Covino, S.; Tagliaferri, G. [INAF-Osservaorio Astronomico di Brera, Merate (Italy); Rossi, E.M. [Max Planck Institut fur Astrophysik, Garching (Germany); Lazzati, D. [Colorado Univ., Boulder (United States). JILA; De Luca [INAF-IASF, Milano (Italy); Filliatre, P. [Laboratoire astroparticule et cosmologie, Paris (France); CEA-DSM-DAPNIA-SAp, Gif-sur-Yvette (France). Service d' Astrophysique

    2005-07-15

    We review some open problems in the physics of afterglows, namely their polarization properties and the existence of dark-faint bursts. Polarization studies yield precious insights in the physical structure and dynamical evolution of GRB jets, revealing their magnetization properties and their energy profile. Polarimetric observations of GRB 020813 already allowed to exclude a homogeneous jet for this event. We then present observations of faint-dark bursts, showing that some of them may be obscured by dust, while others are possibly just intrinsically dim.

  19. Open issues in Gamma-Ray Bursts: Polarimetry and dark GRBs

    International Nuclear Information System (INIS)

    We review some open problems in the physics of afterglows, namely their polarization properties and the existence of dark-faint bursts. Polarization studies yield precious insights in the physical structure and dynamical evolution of GRB jets, revealing their magnetization properties and their energy profile. Polarimetric observations of GRB 020813 already allowed to exclude a homogeneous jet for this event. We then present observations of faint-dark bursts, showing that some of them may be obscured by dust, while others are possibly just intrinsically dim

  20. A magnetar powering the ordinary monster GRB 130427A?

    CERN Document Server

    Bernardini, M G; Ghisellini, G; D'Avanzo, P; Calderone, G; Covino, S; Cusumano, G; Ghirlanda, G; La Parola, V; Maselli, A; Salvaterra, A Melandri R; Burlon, D; D'Elia, V; Fugazza, D; Sbarufatti, B; Vergani, S D; Tagliaferri, G

    2014-01-01

    We present the analysis of the extraordinarily bright Gamma-Ray Burst (GRB) 130427A under the hypothesis that the GRB central engine is an accretion-powered magnetar. In this framework, initially proposed to explain GRBs with precursor activity, the prompt emission is produced by accretion of matter onto a newly-born magnetar, and the observed power is related to the accretion rate. The emission is eventually halted if the centrifugal forces are able to pause accretion. We show that the X-ray and optical afterglow is well explained as the forward shock emission with a jet break plus a contribution from the spin-down of the magnetar. Our modelling does not require any contribution from the reverse shock, that may still influence the afterglow light curve at radio and mm frequencies, or in the optical at early times. We derive the magnetic field ($B\\sim 10^{16}$ G) and the spin period ($P\\sim 20$ ms) of the magnetar and obtain an independent estimate of the minimum luminosity for accretion. This minimum luminos...

  1. Properties of GRB light curves from magnetic reconnection

    Science.gov (United States)

    Beniamini, Paz; Granot, Jonathan

    2016-07-01

    The energy dissipation mechanism within gamma-ray burst (GRB) outflows, driving their extremely luminous prompt γ-ray emission is still uncertain. The leading candidates are internal shocks and magnetic reconnection. While the emission from internal shocks has been extensively studied, that from reconnection still has few quantitative predictions. We study the expected prompt-GRB emission from magnetic reconnection and compare its temporal and spectral properties to observations. The main difference from internal shocks is that for reconnection one expects relativistic bulk motions with Lorentz factors Γ'≳ a few in the jet's bulk frame. We consider such motions of the emitting material in two antiparallel directions (e.g. of the reconnecting magnetic-field lines) within an ultrarelativistic (with Γ ≫ 1) thin spherical reconnection layer. The emission's relativistic beaming in the jet's frame greatly affects the light curves. For emission at radii R0 tracking (for Γ' > 2). However, the relativistic turbulence mode is more likely to be relevant for the prompt sub-MeV emission and can naturally account also for the peak luminosity - peak frequency correlation.

  2. Initial Evolution of GRB Jets with Different Species

    Science.gov (United States)

    Nishikawa, Ken-ichi; Hardee, Phil; Hartmann, Dieter; Niemiec, Jacek; Pohl, Martin; Sol, Helene; Gomez, Jose L.; Nordlund, Aake; Dutan, Ioana; Mizuno, Yosuke; Meli, Athina; Peer, Asaf; Frederiksen, Jacob

    2016-07-01

    In the study of GRB jets one of the key open questions is their interaction with the environment. Here, we study the initial evolution of both electron-proton and electron-positron relativistic jets injected, focusing on their lateral interaction with ambient plasma. We follow the evolution of toroidal magnetic fields generated by both the kinetic Kelvin-Helmholtz (kKH) and Mushroom instabilities (MI). For an electron-proton jet, the induced magnetic field collimates the jet and electrons are perpendicularly accelerated. As the instabilities saturate and subsequently weaken, the magnetic polarity switches from clockwise to counter-clockwise in the middle of jet. For an electron-positron jet, we find strong mixing of electrons and positrons with the ambient plasma, resulting in the creation of a bow shock. The merging of current filaments generates density inhomogeneities which initiate a forward shock. Strong jet ambient plasma mixing prevents a full development of the jet (on the scale studied), revealing evidence for both jet collimation and particle acceleration in the forming bow shock. Differences in the magnetic field structure generated by different jets may contribute to the polarization properties of the observed emission in gamma ray bursts. The different electron acceleration mechanisms in different jets may affect the light-curves in GRB observations.

  3. Discovery of GRB 020405 and its Underlying Supernova

    CERN Document Server

    Price, P A; Berger, E; Fox, D W; Bloom, J S; Djorgovski, S G; Frail, D A; Galama, T J; Harrison, F A; McCarthy, P; Reichart, D E; Sari, R; Yost, S A; Jerjen, H; Flint, K; Phillips, A; Warren, B E; Axelrod, T S; Chevalier, R A; Halpern, J P; Holtzmann, J A; Kimble, R A; Schmidt, B P; Wheeler, J C; Frontera, F; Costa, E; Piro, L; Hurley, K; Cline, T; Guidorzi, C; Montanari, E; Mazets, E; Golenetskii, S V; Mitrofanov, I G; Anfimov, D; Kozyrev, A B; Litvak, M; Sanin, A; Boynton, W; Fellows, C; Harshman, K; Shinohara, C; Gal-Yam, A; Ofek, E O; Lipkin, Yu M

    2002-01-01

    We present the discovery of GRB 020405 made with the Inter-Planetary Network (IPN). With a duration of 60 s, the burst appears to be a typical long duration event. We observed the 75-square acrminute IPN error region with the Mount Stromlo Observatory's 50-inch robotic telescope and discovered a transient source which subsequently decayed and was also associated with a variable radio source. We identify this source as the afterglow of GRB 020405. Subsequent observations by other groups found varying polarized flux and established a redshift of 0.690 to the host galaxy. Motivated by the low redshift we triggered observations with WFPC2 on-board the Hubble Space Telescope (HST). Modeling the early ground-based data with a jet model, we find a clear red excess over the decaying optical lightcurves that is present between day 10 and day 50 (the last HST epoch). This "bump" has the spectral and temporal features expected of an underlying supernova (SN). In particular, the red color of the putative SN is similar to...

  4. Effect of GRB spectra on the empirical luminosity correlations and the GRB Hubble diagram

    CERN Document Server

    Lin, Hai-Nan; Chang, Zhe

    2016-01-01

    The spectra of gamma-ray bursts (GRBs) in a wide energy range can usually be well described by the Band function, which is a two smoothly jointed power laws cutting at a breaking energy. Below the breaking energy, the Band function reduces to a cut-off power law, while above the breaking energy it is a simple power law. However, for some detectors (such as the Swift-BAT) whose working energy is well below or just near the breaking energy, the observed spectra can be fitted to cut-off power law with enough precision. Besides, since the energy band of Swift-BAT is very narrow, the spectra of most GRBs can be fitted well even using a simple power law. In this paper, with the most up-to-date sample of Swift-BAT GRBs, we study the effect of different spectral models on the empirical luminosity correlations, and further investigate the effect on the reconstruction of GRB Hubble diagram. We mainly focus on two luminosity correlations, i.e., the Amati relation and Yonetoku relation. We calculate these two luminosity ...

  5. The supernova-gamma-ray burst-jet connection.

    Science.gov (United States)

    Hjorth, Jens

    2013-06-13

    The observed association between supernovae and gamma-ray bursts represents a cornerstone in our understanding of the nature of gamma-ray bursts. The collapsar model provides a theoretical framework for this connection. A key element is the launch of a bipolar jet (seen as a gamma-ray burst). The resulting hot cocoon disrupts the star, whereas the (56)Ni produced gives rise to radioactive heating of the ejecta, seen as a supernova. In this discussion paper, I summarize the observational status of the supernova-gamma-ray burst connection in the context of the 'engine' picture of jet-driven supernovae and highlight SN 2012bz/GRB 120422A--with its luminous supernova but intermediate high-energy luminosity--as a possible transition object between low-luminosity and jet gamma-ray bursts. The jet channel for supernova explosions may provide new insights into supernova explosions in general. PMID:23630379

  6. THE OPTICALLY UNBIASED GRB HOST (TOUGH) SURVEY. VI. RADIO OBSERVATIONS AT z {approx}< 1 AND CONSISTENCY WITH TYPICAL STAR-FORMING GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Michalowski, M. J.; Dunlop, J. S. [SUPA (Scottish Universities Physics Alliance), Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh EH9 3HJ (United Kingdom); Kamble, A.; Kaplan, D. L. [Physics Department, University of Wisconsin-Milwaukee, Milwaukee, WI 53211 (United States); Hjorth, J.; Malesani, D.; Fynbo, J. P. U.; Kruehler, T. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen O (Denmark); Reinfrank, R. F. [CSIRO Astronomy and Space Science, P.O. Box 76, Epping, NSW 1710 (Australia); Bonavera, L. [Instituto de Fisica de Cantabria, CSIC-Universidad de Cantabria, Avda. de los Castros s/n, E-39005 Santander (Spain); Castro Ceron, J. M. [Department of Radio Astronomy, Madrid Deep Space Communications Complex (INTA-NASA/INSA), Ctra. M-531, km. 7, E-28.294 Robledo de Chavela (Madrid) (Spain); Ibar, E. [UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Garrett, M. A. [Netherlands Institute for Radio Astronomy (ASTRON), Postbus 2, 7990 AA Dwingeloo (Netherlands); Jakobsson, P. [Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Dunhagi 5, 107 Reykjavik (Iceland); Levan, A. J. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Massardi, M. [INAF-Istituto di Radioastronomia, via Gobetti 101, I-40129 Bologna (Italy); Pal, S. [ICRAR, University of Western Australia, 35 Stirling Highway, Crawley, WA (Australia); Sollerman, J. [Oskar Klein Centre, Department of Astronomy, AlbaNova, Stockholm University, SE-10691 Stockholm (Sweden); Tanvir, N. R. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Van der Horst, A. J., E-mail: mm@roe.ac.uk [Astronomical Institute ' Anton Pannekoek' , University of Amsterdam, Science Park 904, 1098XH Amsterdam (Netherlands); and others

    2012-08-20

    The objective of this paper is to determine the level of obscured star formation activity and dust attenuation in a sample of gamma-ray burst (GRB) hosts, and to test the hypothesis that GRB hosts have properties consistent with those of the general star-forming galaxy populations. We present a radio continuum survey of all z < 1 GRB hosts in The Optically Unbiased GRB Host (TOUGH) sample supplemented with radio data for all (mostly pre-Swift) GRB-SN hosts discovered before 2006 October. We present new radio data for 22 objects and have obtained a detection for three of them (GRB 980425, 021211, 031203; none in the TOUGH sample), increasing the number of radio-detected GRB hosts from two to five. The star formation rate (SFR) for the GRB 021211 host of {approx}825 M{sub Sun} yr{sup -1}, the highest ever reported for a GRB host, places it in the category of ultraluminous infrared galaxies. We found that at least {approx}63% of GRB hosts have SFR < 100 M{sub Sun} yr{sup -1} and at most {approx}8% can have SFR > 500 M{sub Sun} yr{sup -1}. For the undetected hosts the mean radio flux (<35 {mu}Jy 3{sigma}) corresponds to an average SFR < 15 M{sub Sun} yr{sup -1}. Moreover, {approx}> 88% of the z {approx}< 1 GRB hosts have ultraviolet dust attenuation A{sub UV} < 6.7 mag (visual attenuation A{sub V} < 3 mag). Hence, we did not find evidence for large dust obscuration in a majority of GRB hosts. Finally, we found that the distributions of SFRs and A{sub UV} of GRB hosts are consistent with those of Lyman break galaxies, H{alpha} emitters at similar redshifts, and of galaxies from cosmological simulations. The similarity of the GRB population with other star-forming galaxies is consistent with the hypothesis that GRBs, a least at z {approx}< 1, trace a large fraction of all star formation, and are therefore less biased indicators than once thought.

  7. ESA's Integral detects closest cosmic gamma-ray burst

    Science.gov (United States)

    2004-08-01

    5 August 2004 A gamma-ray burst detected by ESA's Integral gamma-ray observatory on 3 December 2003 has been thoroughly studied for months by an armada of space and ground-based observatories. Astronomers have now concluded that this event, called GRB 031203, is the closest cosmic gamma-ray burst on record, but also the faintest. This also suggests that an entire population of sub-energetic gamma-ray bursts has so far gone unnoticed... Gamma ray burst model hi-res Size hi-res: 22 KB Credits: CXC/M. Weiss Artist impression of a low-energy gamma-ray burst This illustration describes a model for a gamma-ray burst, like the one detected by Integral on 3 December 2003 (GRB 031203). A jet of high-energy particles from a rapidly rotating black hole interacts with surrounding matter. Observations with Integral on 3 December 2003 and data on its afterglow, collected afterwards with XMM-Newton, Chandra and the Very Large Array telescope, show that GRB 031203 radiated only a fraction of the energy of normal gamma-ray bursts. Like supernovae, gamma-ray bursts are thought to be produced by the collapse of the core of a massive star. However, while the process leading to supernovae is relatively well understood, astronomers still do not know what happens when a core collapses to form a black hole. The discovery of 'under-energetic' gamma-ray bursts, like GRB 031203, should provide valuable clues as to links between supernovae, black holes and gamma-ray bursts. Lo-res JPG (22 Kb) Hi-res TIFF (5800 Kb) Cosmic gamma-ray bursts (GRBs) are flashes of gamma rays that can last from less than a second to a few minutes and occur at random positions in the sky. A large fraction of them is thought to result when a black hole is created from a dying star in a distant galaxy. Astronomers believe that a hot disc surrounding the black hole, made of gas and matter falling onto it, somehow emits an energetic beam parallel to the axis of rotation. According to the simplest picture, all GRBs

  8. GRB Astrophysics in the Swift Era and Beyond

    CERN Document Server

    Stamatikos, Michael

    2009-01-01

    Gamma-ray Bursts (GRBs) are relativistic cosmological beacons of transient high energy radiation whose afterglows span the electromagnetic spectrum. Theoretical expectations of correlated neutrino emission position GRBs at an astrophysical nexus for a metamorphosis in our understanding of the Cosmos. This new dawn in the era of experimental (particle) astrophysics and cosmology is afforded by current facilities enabling the novel astronomy of high energy neutrinos, in concert with unprecedented electromagnetic coverage. In that regard, GRBs represent a compelling scientific theme that may facilitate fundamental breakthroughs in the context of Swift, Fermi and IceCube. Scientific synergy will be achieved by leveraging the combined sensitivity of contemporaneous ground-based and satellite observatories, thus optimizing their collective discovery potential. Hence, the advent of GRB multi-messenger astronomy may cement an explicit connection to fundamental physics, via nascent cosmic windows, throughout the next ...

  9. Gamma-Ray Bursts at high and very high energies

    CERN Document Server

    Piron, F

    2015-01-01

    Gamma-Ray Bursts (GRBs) are extra-galactic and extremely energetic transient emissions of gamma rays, which are thought to be associated with the death of massive stars or the merger of compact objects in binary systems. Their huge luminosities involve the presence a newborn stellar-mass black hole emitting a relativistic collimated outflow, which accelerates particles and produces non-thermal emissions from the radio domain to the highest energies. In this article, I review recent progresses in the understanding of GRB jet physics above 100 MeV, based on Fermi observations of bright GRBs. I discuss the physical implications of these observations and their impact on GRB modeling, and I present some prospects for GRB observation at very high energies in the near future.

  10. Gamma-ray bursts at high and very high energies

    Science.gov (United States)

    Piron, Frédéric

    2016-06-01

    Gamma-Ray Bursts (GRBs) are extra-galactic and extremely energetic transient emissions of gamma rays, which are thought to be associated with the death of massive stars or the merger of compact objects in binary systems. Their huge luminosities involve the presence of a newborn stellar-mass black hole emitting a relativistic collimated outflow, which accelerates particles and produces non-thermal emissions from the radio domain to the highest energies. In this article, I review recent progresses in the understanding of GRB jet physics above 100 MeV, based on Fermi observations of bright GRBs. I discuss the physical implications of these observations and their impact on GRB modeling, and I present some prospects for GRB observation at very high energies in the near future. xml:lang="fr"

  11. The ultra-long GRB 111209A - II. Prompt to afterglow and afterglow properties

    CERN Document Server

    Stratta, G; Atteia, J L; Boër, M; Coward, D M; De Pasquale, M; Howell, E; Klotz, A; Oates, S; Piro, L

    2013-01-01

    The "ultra-long" Gamma Ray Burst GRB 111209A at redshift z=0.677, is so far the longest GRB ever observed, with rest frame prompt emission duration of ~4 hours. In order to explain the bursts exceptional longevity, a low metallicity blue supergiant progenitor has been invoked. In this work, we further investigate this peculiar burst by performing a multi-band temporal and spectral analysis of both the prompt and the afterglow emission. We use proprietary and publicly available data from Swift, Konus Wind, XMM-Newton, TAROT as well as from other ground based optical and radio telescopes. We find some peculiar properties that are possibly connected to the exceptional nature of this burst, namely: i) an unprecedented large optical delay of 410+/-50 s is measured between the peak epochs of a marked flare observed also in gamma-rays after about 2 ks from the first Swift/BAT trigger; ii) if the optical and X-ray/gamma-ray photons during the prompt emission share a common origin, as suggested by their similar tempor...

  12. Modeling GRB 050904: Autopsy of a Massive Stellar Explosion at z=6.29

    CERN Document Server

    Gou, L J; Mészáros, P

    2006-01-01

    GRB 050904 at redshift z=6.29, discovered and observed by Swift and with spectroscopic redshift from the Subaru telescope, is the first gamma-ray burst to be identified from beyond the epoch of reionization. Since the progenitors of long gamma-ray bursts have been identified as massive stars, this event offers a unique opportunity to investigate star formation environments at this epoch. Apart from its record redshift, the burst is remarkable in two respects: first, it exhibits fast-evolving X-ray and optical flares that peak simultaneously at t~470 s in the observer frame, and may thus originate in the same emission region; and second, its afterglow exhibits an accelerated decay in the near-infrared (NIR) from t~10^4 s to t~3 10^4 s after the burst, coincident with repeated and energetic X-ray flaring activity. We make a complete analysis of available X-ray, NIR, and radio observations, utilizing afterglow models that incorporate a range of physical effects not previously considered for this or any other GRB...

  13. Gamma-Ray Bursts 2012 Conference

    Science.gov (United States)

    It is a pleasure to announce the next combined Fermi/Swift GRB conference covering recent advances in all aspects of gamma-ray burst observations and theory. This conference will be held in Munich, Germany, on 7-11 May 2012, and follows similar previous combined Fermi/Swift meetings in Huntsville (Oct. 2008) and Annapolis (Nov. 2010). Gamma-ray bursts are the most energetic explosions in the Universe and are thought to be the birth signatures of black holes. This is an exciting time in the GRB field as various missions provide a wealth of new data on this still puzzling phenomenon. The Fermi misson provides unprecedented spectral coverage over 7 decades in energy, and among others discovered new spectral components which challenge our standard picture of the prompt emission. The Swift mission continuous to swiftly monitor and locate GRBs in multiple wavebands, providing the basis for all ground-based follow-up observations towards redshift measurements and afterglow and host property investigations. AGILE, INTEGRAL, Suzaku and Konus continue to provide crucial information on GRB properties, and the MAXI mission provides an all sky X-ray monitoring of transients. There is also growing capability for follow-up observations by ground-based telescopes at basically all wavelengths. Besides the classical optical/infrared/radio observations, searches are underway for TeV emission, neutrinos and gravitational waves. Moreover, new experiments are expected to have returned first data, among others POGO on the prompt polarization properties, UFFO on very early optical emission, or ALMA on sub-millimeter properties. And last but not least, the unexpected is bringing us child-like astonishments at least once per year with a "GRB-trigger" which turns out to be not related to GRBs. Complementing all these new observational results, a huge theoretical effort is underway to understand the GRB phenomenon and keep up with the constant new puzzles coming from the data. This conference

  14. Hubble Space Telescope Observations of the Afterglow, Supernova and Host Galaxy Associated with the Extremely Bright GRB 130427A

    Science.gov (United States)

    Levan, A.J.; Tanvir, N. R.; Fruchter, A. S.; Hjorth, J.; Pian, E.; Mazzali, P.; Hounsell, R. A.; Perley, D. A.; Cano, Z.; Graham, J.; Cenko, S. B.; Fynbo, J. P. U.; Kouveliotou, C.; Pe'er, A.; Misra, K.; Wiersema, K.

    2014-01-01

    We present Hubble Space Telescope (HST) observations of the exceptionally bright and luminous Swift gamma-ray burst, GRB 130427A. At z=0.34 this burst affords an excellent opportunity to study the supernova and host galaxy associated with an intrinsically extremely luminous burst (E(sub iso) greater than 10(exp 54) erg): more luminous than any previous GRB with a spectroscopically associated supernova. We use the combination of the image quality, UV capability and and invariant PSF of HST to provide the best possible separation of the afterglow, host and supernova contributions to the observed light approximately 17 rest-frame days after the burst utilising a host subtraction spectrum obtained 1 year later. Advanced Camera for Surveys (ACS) grism observations show that the associated supernova, SN 2013cq, has an overall spectral shape and luminosity similar to SN 1998bw (with a photospheric velocity, vph approximately 15,000 kilometers per second). The positions of the bluer features are better matched by the higher velocity SN 2010bh (vph approximately 30,000 kilometers per second), but SN 2010bh (vph approximately 30,000 kilometers per second but this SN is significantly fainter, and fails to reproduce the overall spectral shape, perhaps indicative of velocity structure in the ejecta. We find that the burst originated approximately 4 kpc from the nucleus of a moderately star forming (1 Solar Mass yr(exp-1)), possibly interacting disc galaxy. The absolute magnitude, physical size and morphology of this galaxy, as well as the location of the GRB within it are also strikingly similar to those of GRB980425SN 1998bw. The similarity of supernovae and environment from both the most luminous and least luminous GRBs suggests broadly similar progenitor stars can create GRBs across six orders of magnitude in isotropic energy.

  15. Analysis of GRB 080319B and GRB 050904 within the fireshell model: evidence for a broader spectral energy distribution

    CERN Document Server

    Patricelli, Barbara; Bianco, Carlo Luciano; Caito, Letizia; de Barros, Gustavo; Izzo, Luca; Ruffini, Remo; Vereshchagin, Gregory

    2012-01-01

    (Shortened) GRB080319B, with an isotropic energy E_{iso}=1.32x10^{54}erg, and GRB050904, with E_{iso}=1.04x10^{54}erg, offer the possibility of studying the spectral properties of the prompt radiation of two of the most energetic Gamma-Ray Bursts (GRBs). This allows us to probe the validity of the fireshell model for GRBs beyond 10^{54}erg, well outside the energy range where it has been successfully tested up to now (10^{49}-10^{53}erg). We find that in the low energy region, the prompt emission spectra observed by Swift BAT reveals more power than theoretically predicted. The opportunities offered by these observations to improve the fireshell model are outlined. One of the distinguishing features of the fireshell model is that it relates the observed spectra to the spectrum in the comoving frame of the fireshell. Originally, a fully radiative condition and a comoving thermal spectrum were adopted. An additional power-law in the comoving thermal spectrum is required [...] in the fireshell model for GRBs 080...

  16. Jet or Shock Breakout? The Low-Luminosity GRB 060218

    Science.gov (United States)

    Irwin, Christopher M.; Chevalier, Roger A.

    2016-05-01

    We consider a model for the low-luminosity gamma-ray burst GRB 060218 that plausibly accounts for multiwavelength observations to day 20. The model components are: (1) a long-lived (tj ˜ 3000 s) central engine and accompanying low-luminosity (Lj ˜ 1047 erg s-1), mildly relativistic (γ ˜ 10) jet; (2) a low-mass (˜4 × 10-3M⊙) envelope surrounding the progenitor star; and (3) a modest amount of dust (AV ˜ 0.1 mag) in the circumstellar or interstellar environment. Blackbody emission from the transparency radius in a low-power jet outflow can fit the prompt thermal X-ray emission, and the nonthermal X-rays and γ-rays may be produced via Compton scattering of thermal photons from hot leptons in the jet interior or the external shocks. The later mildly relativistic phase of this outflow can produce the radio emission via synchrotron radiation from the forward shock. Meanwhile, interaction of the associated SN 2006aj with a circumstellar envelope extending to ˜1013 cm can explain the early optical emission. The X-ray afterglow can be interpreted as a light echo of the prompt emission from dust at ˜30 pc. Our model is a plausible alternative to that of Nakar, who recently proposed shock breakout of a jet smothered by an extended envelope as the source of prompt emission. Both our results and Nakar's suggest that bursts such as GRB 060218 may originate from unusual progenitors with extended circumstellar envelopes, and that a jet is necessary to decouple the prompt emission from the supernova.

  17. Jet or shock breakout? The low-luminosity GRB 060218

    Science.gov (United States)

    Irwin, Christopher M.; Chevalier, Roger A.

    2016-08-01

    We consider a model for the low-luminosity gamma-ray burst GRB 060218 that plausibly accounts for multiwavelength observations to day 20. The model components are: (1) a long-lived (tj ˜ 3000 s) central engine and accompanying low-luminosity (Lj ˜ 1047 erg s-1), mildly relativistic (γ ˜ 10) jet; (2) a low-mass (˜4 × 10-3 M⊙) envelope surrounding the progenitor star; and (3) a modest amount of dust (AV ˜ 0.1 mag) in the circumstellar or interstellar environment. Blackbody emission from the transparency radius in a low-power jet outflow can fit the prompt thermal X-ray emission, and the non-thermal X-rays and gamma-rays may be produced via Compton scattering of thermal photons from hot leptons in the jet interior or the external shocks. The later mildly relativistic phase of this outflow can produce the radio emission via synchrotron radiation from the forward shock. Meanwhile, interaction of the associated SN 2006aj with a circumstellar envelope extending to ˜1013 cm can explain the early optical emission. The X-ray afterglow can be interpreted as a light echo of the prompt emission from dust at ˜30 pc. Our model is a plausible alternative to that of Nakar, who recently proposed shock breakout of a jet smothered by an extended envelope as the source of prompt emission. Both our results and Nakar's suggest that bursts such as GRB 060218 may originate from unusual progenitors with extended circumstellar envelopes, and that a jet is necessary to decouple the prompt emission from the supernova.

  18. A Photometric Redshift of z ~ 9.4 for GRB 090429B

    CERN Document Server

    Cucchiara, A; Fox, D B; Tanvir, N R; Ukwatta, T N; Berger, E; Krühler, T; Yoldaş, A Küpcü; Wu, X F; Toma1, K; Greiner, J; E., F Olivares; Rowlinson, A; Amati, L; Sakamoto, T; Roth, K; Stephens, A; Fynbo, J P U; Hjorth, J; Malesani, D; Jakobsson, P; Wiersema, K; O'Brien, P T; Soderberg, A M; Foley, R J; Fruchter, A S; Rhoads, J; Rutledge, R E; Schmidt, B P; Dopita, M A; Podsiadlowski, P; Willingale, R; Wolf, C; Kulkarni, S R; D'Avanzo, P

    2011-01-01

    Gamma-ray bursts (GRBs) serve as powerful probes of the early Universe, with their luminous afterglows revealing the locations and physical properties of star forming galaxies at the highest redshifts, and potentially locating first generation (Population III) stars. Since GRB afterglows have intrinsically very simple spectra, they allow robust redshifts from low signal to noise spectroscopy, or photometry. Here we present a photometric redshift of $z \\sim 9.4$ for the {\\em Swift} detected GRB 090429B based on deep observations with Gemini-North, the Very Large Telescope, and the GRB Optical and Near-infrared Detector. Assuming an Small Magellanic Cloud dust law (which has been found in a majority of GRB sight-lines), the 90% likelihood range for the redshift is $9.067$. The non-detection of the host galaxy to deep limits ($Y$(AB) $\\sim 28$, which would correspond roughly to 0.001$L^*$ at $z=1$) in our late time optical and infrared observations with the {\\em Hubble Space Telescope}, strongly supports the ext...

  19. Discovery and identification of the very high redshift afterglow of GRB 050904

    CERN Document Server

    Haislip, J; Reichart, D; Levan, A; Tanvir, N; Cenko, S; Fox, D; Price, P; Castro-Tirado, A J; Gorosabel, J; Evans, C; Figueredo, E; MacLeod, C; Kirschbrown, J; Jelinek, M; Guziy, S; De Postigo, A U; Cypriano, E S; La Cluyze, A; Graham, J; Priddey, R; Chapman, R; Rhoads, J; Fruchter, A; Lamb, D; Kouveliotou, C; Wijers, R A M J; Schmidt, B; Soderberg, A M; Kulkarni, S; Harrison, F; Moon, D; Gal-Yam, A; Kasliwal, M; Hudec, R; Vítek, S; Kubánek, P; Crain, J; Foster, A; Bayliss, M; Clemens, J; Bartelme, J

    2005-01-01

    In 2000, Lamb and Reichart predicted that gamma-ray bursts (GRBs) and their afterglows occur in sufficient numbers and at sufficient brightnesses at very high redshifts (z > 5) to eventually replace quasars as the preferred probe of element formation and reionization in the early universe and to be used to characterize the star-formation history of the early universe, perhaps back to when the first stars formed. Here we report the discovery of the afterglow of GRB 050904 and the identification of GRB 050904 as the first very high redshift GRB. We measure its redshift to be 6.39(+0.11,-0.12), which is consistent with the reported spectroscopic redshift (6.29 +/- 0.01). Furthermore, just redward of Ly-alpha the flux is suppressed by a factor of three on the first night, but returns to expected levels by the fourth night. We propose that this is due to absorption by molecular hydrogen that was excited to rovibrational states by the GRB's prompt emission, but was then overtaken by the jet. Now that very high reds...

  20. Is GRB 050904 at z=6.3 absorbed by dust?

    CERN Document Server

    Stratta, G; Maiolino, R

    2011-01-01

    Claim of dust extinction for this GRB has been debated in the past. We suggest that the discrepant results occur primarily because most of previous studies have not simultaneously investigated the X-ray to near-IR spectral energy distribution of this GRB. The difficulty with this burst is that the X-ray afterglow is dominated by strong flares at early times and is poorly monitored at late times. In addition, the Z band photometry, which is the most sensitive to dust extinction, has been found to be affected by strong systematics. In this paper we carefully re-analyze the Swift/XRT afterglow observations of this GRB, using extensive past studies of X-ray flare properties when computing the X-ray afterglow flux level and exploiting the recent reanalysis of the optical (UV rest frame) data of the same GRB. We extract the X-ray to optical/near-IR afterglow SED for the three epochs where the best spectral coverage is available: 0.47, 1.25, and 3.4 days after the trigger. A spectral power-law model has been fitted ...

  1. Spectrophotometric analysis of GRB afterglow extinction curves with X-shooter

    CERN Document Server

    Japelj, J; Gomboc, A; Vergani, S D; Goldoni, P; Selsing, J; Cano, Z; D'Elia, V; Flores, H; Fynbo, J P U; Hammer, F; Hjorth, J; Jakobsson, P; Kaper, L; Kopač, D; Krühler, T; Melandri, A; Piranomonte, S; Sánchez-Ramírez, R; Tagliaferri, G; Tanvir, N R; Postigo, A de Ugarte; Watson, D; Wijers, R A M J

    2015-01-01

    In this work we use gamma-ray burst (GRB) afterglow spectra observed with the VLT/X-shooter spectrograph to measure rest-frame extinction in GRB lines-of-sight by modeling the broadband near-infrared (NIR) to X-ray afterglow spectral energy distributions (SEDs). Our sample consists of nine Swift GRBs, eight of them belonging to the long-duration and one to the short-duration class. Dust is modeled using the average extinction curves of the Milky Way and the two Magellanic Clouds. We derive the rest-frame extinction of the entire sample, which fall in the range $0 \\lesssim {\\it A}_{\\rm V} \\lesssim 1.2$. Moreover, the SMC extinction curve is the preferred extinction curve template for the majority of our sample, a result which is in agreement with those commonly observed in GRB lines-of-sights. In one analysed case (GRB 120119A), the common extinction curve templates fail to reproduce the observed extinction. To illustrate the advantage of using the high-quality X-shooter afterglow SEDs over the photometric SED...

  2. The low-extinction afterglow in the solar-metallicity host galaxy of GRB 110918A

    CERN Document Server

    Elliott, J; Greiner, J; Savaglio, S; E., F Olivares; Rau, A; Postigo, A de Ugarte; Sánchez-Ramírez, R; Wiersema, K; Schady, P; Kann, D A; Filgas, R; Nardini, M; Berger, E; Fox, D; Gorosabel, J; Klose, S; Levan, A; Guelbenzu, A Nicuesa; Rossi, A; Schmidl, S; Sudilovsky, V; Tanvir, N R; Thöne, C C

    2013-01-01

    Galaxies selected through long gamma-ray bursts (GRBs) could be of fundamental importance when mapping the star formation history out to the highest redshifts. Before using them as efficient tools in the early Universe, however, the environmental factors that govern the formation of GRBs need to be understood. Metallicity is theoretically thought to be a fundamental driver in GRB explosions and energetics, but is still, even after more than a decade of extensive studies, not fully understood. This is largely related to two phenomena: a dust-extinction bias, that prevented high-mass and thus likely high-metallicity GRB hosts to be detected in the first place, and a lack of efficient instrumentation, that limited spectroscopic studies including metallicity measurements to the low-redshift end of the GRB host population. The subject of this work is the very energetic GRB 110918A, for which we measure one of the largest host-integrated metallicities, ever, and the highest stellar mass for z<1.9. This presents ...

  3. GRB 080503 late afterglow re-brightening: signature of a magnetar powered merger-nova

    CERN Document Server

    Gao, He; Wu, Xue-Feng; Dai, Zi-Gao; Zhang, Bing

    2015-01-01

    GRB 080503 is a short gamma-ray burst (GRB) detected by \\emph{Swift} and has been classified as a compact-star-merger-origin GRB. The soft extended emission and the simultaneous late re-brightening in both the X-ray and optical afterglow lightcurves raise interesting questions regarding its physical origin. We show that the broad-band data of GRB 080503 can be well explained within the framework of the double neutron star merger model, provided that the merger remnant is a rapidly-rotating massive neutron star with an extremely high magnetic field (i.e. a millisecond magnetar). We show that the late optical re-brightening is consistent with the emission from a magnetar-powered "merger-nova". This adds one more case to the growing sample of merger-novae associated with short GRBs. The soft extended emission and the late X-ray excess emission are well connected through a magnetar dipole spin-down luminosity evolution function, suggesting that direct magnetic dissipation is the mechanism to produce these X-rays....

  4. A cross-correlation search for intermediate-duration gravitational waves from GRB magnetars

    Science.gov (United States)

    Coyne, Robert

    2015-04-01

    Since the discovery of the afterglow in 1997, the progress made in our understanding of gamma-ray bursts (GRBs) has been spectacular. Yet a direct proof of GRB progenitors is still missing. In the last few years, evidence for a long-lived and sustained central engine in GRBs has mounted. This has called attention to the so-called millisecond-magnetar model, which proposes that a highly magnetized, rapidly-rotating neutron star may exist at the heart of some of these events. The advent of advanced gravitational wave detectors such as LIGO and Virgo may enable us to probe directly, for the first time, the nature of GRB progenitors and their byproducts. In this context, we describe a novel application of a generalized cross-correlation technique optimized for the detection of long-duration gravitational wave signals that may be associated with bar-like deformations of GRB magnetars. The detection of these signals would allow us to answer some of the most intriguing questions on the nature of GRB progenitors, and serve as a starting point for a new class of intermediate-duration gravitational wave searches.

  5. The Swift Gamma-Ray Burst Mission

    CERN Document Server

    Gehrels, N; Burrows, D N; Chincarini, G L; Cominsky, L R; Giommi, P; Hurley, K C; Marshall, F E; Mason, K O; Mészáros, P; Nousek, J A; Roming, P W A; Wells, A A; White, N E; Team, Swift Science

    2004-01-01

    The Swift mission, scheduled for launch in early 2004, is a multiwavelength observatory for gamma-ray burst (GRB) astronomy. It is the first-of-its-kind autonomous rapid-slewing satellite for transient astronomy and pioneers the way for future rapid-reaction and multiwavelength missions. It will be far more powerful than any previous GRB mission, observing more than 100 bursts per year and performing detailed X-ray and UV/optical afterglow observations spanning timescales from 1 minute to several days after the burst. The objectives are to determine the origin of GRBs; classify GRBs and search for new types; study the interaction of the ultra-relativistic outflows of GRBs with their surrounding medium; and use GRBs to study the early universe out to z>10. The mission is being developed by a NASA-led international collaboration. It will carry three instruments: a new-generation wide-field gamma-ray (15-150 keV) detector; a narrow-field X-ray telescope; and a narrow-field UV/optical telescope. Redshift determin...

  6. The First Swift Ultra-Violet/Optical Telescope GRB Afterglow Catalog

    CERN Document Server

    Roming, P W A; Oates, S R; Porterfield, B L; Berk, D E Vanden; Boyd, P T; Holland, S T; Hoversten, E A; Immler, S; Marshall, F E; Page, M J; Racusin, J L; Schneider, D P; Breeveld, A A; Brown, P J; Chester, M M; Cucchiara, A; De Pasquale, M; Gronwall, C; Hunsberger, S D; Kuin, N P M; Landsman, W B; Schady, P; Still, M

    2008-01-01

    We present the first Swift Ultra-Violet/Optical Telescope (UVOT) gamma-ray burst (GRB) afterglow catalog. The catalog contains data from over 64,000 independent UVOT image observations of 229 GRBs first detected by Swift, the High Energy Transient Explorer 2 (HETE2), the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL), and the Interplanetary Network (IPN). The catalog covers GRBs occurring during the period from 2005 Jan 17 to 2007 Jun 16 and includes ~86% of the bursts detected by the Swift Burst Alert Telescope (BAT). The catalog provides detailed burst positional, temporal, and photometric information extracted from each of the UVOT images. Positions for bursts detected at the 3-sigma-level are provided with a nominal accuracy, relative to the USNO-B1 catalog, of ~0.25 arcseconds. Photometry for each burst is given in three UV bands, three optical bands, and a 'white' or open filter. Upper limits for magnitudes are reported for sources detected below 3-sigma. General properties of the burst samp...

  7. Estimates for Lorentz factors of gamma-ray bursts from early optical afterglow observations

    International Nuclear Information System (INIS)

    The peak time of optical afterglow may be used as a proxy to constrain the Lorentz factor Γ of the gamma-ray burst (GRB) ejecta. We revisit this method by including bursts with optical observations that started when the afterglow flux was already decaying; these bursts can provide useful lower limits on Γ. Combining all analyzed bursts in our sample, we find that the previously reported correlation between Γ and the burst luminosity L γ does not hold. However, the data clearly show a lower bound Γmin that increases with L γ. We suggest an explanation for this feature: explosions with large jet luminosities and Γ < Γmin suffer strong adiabatic cooling before their radiation is released at the photosphere; they produce weak bursts, barely detectable with present instruments. To test this explanation, we examine the effect of adiabatic cooling on the GRB location in the L γ – Γ plane using a Monte Carlo simulation of the GRB population. Our results predict detectable on-axis 'orphan' afterglows. We also derive upper limits on the density of the ambient medium that decelerates the explosion ejecta. We find that the density in many cases is smaller than expected for stellar winds from normal Wolf-Rayet progenitors. The burst progenitors may be peculiar massive stars with weaker winds, or there might exist a mechanism that reduces the stellar wind a few years before the explosion.

  8. Estimates for Lorentz factors of gamma-ray bursts from early optical afterglow observations

    Energy Technology Data Exchange (ETDEWEB)

    Hascoët, Romain; Beloborodov, Andrei M. [Physics Department and Columbia Astrophysics Laboratory, Columbia University, 538 West 120th Street, New York, NY 10027 (United States); Daigne, Frédéric; Mochkovitch, Robert, E-mail: hascoet@astro.columbia.edu [Institut d' Astrophysique de Paris, UMR 7095 Université Pierre et Marie Curie-CNRS, 98 bis boulevard Arago, F-75014 Paris (France)

    2014-02-10

    The peak time of optical afterglow may be used as a proxy to constrain the Lorentz factor Γ of the gamma-ray burst (GRB) ejecta. We revisit this method by including bursts with optical observations that started when the afterglow flux was already decaying; these bursts can provide useful lower limits on Γ. Combining all analyzed bursts in our sample, we find that the previously reported correlation between Γ and the burst luminosity L {sub γ} does not hold. However, the data clearly show a lower bound Γ{sub min} that increases with L {sub γ}. We suggest an explanation for this feature: explosions with large jet luminosities and Γ < Γ{sub min} suffer strong adiabatic cooling before their radiation is released at the photosphere; they produce weak bursts, barely detectable with present instruments. To test this explanation, we examine the effect of adiabatic cooling on the GRB location in the L {sub γ} – Γ plane using a Monte Carlo simulation of the GRB population. Our results predict detectable on-axis 'orphan' afterglows. We also derive upper limits on the density of the ambient medium that decelerates the explosion ejecta. We find that the density in many cases is smaller than expected for stellar winds from normal Wolf-Rayet progenitors. The burst progenitors may be peculiar massive stars with weaker winds, or there might exist a mechanism that reduces the stellar wind a few years before the explosion.

  9. GRB 120521C at z~6 and the Properties of High-redshift GRBs

    CERN Document Server

    Laskar, T; Tanvir, N; Zauderer, B; Margutti, R; Levan, A; Perley, D; Fong, W; Wiersema, K; Cucchiara, A; Menten, K; Hrudkova, M

    2013-01-01

    We present optical, near-infrared, and radio observations of the afterglow of GRB 120521C. By modeling the multi-wavelength dataset, we derive a photometric redshift of z~6.0, which we confirm with a low signal-to-noise ratio spectrum of the afterglow. We find that a model with a constant-density environment provides a good fit to the afterglow data, with an inferred density of 0.05/cm^3. The radio observations reveal the presence of a jet break at 7 d, corresponding to a jet opening angle of ~ 3 deg. The beaming-corrected gamma-ray and kinetic energies are both ~ 3e50 erg. We quantify the uncertainties in our results using a detailed Markov Chain Monte Carlo analysis, which allows us to uncover degeneracies between the physical parameters of the explosion. To compare GRB 120521C to other high-redshift bursts in a uniform manner we re-fit all available afterglow data for the two other bursts at z>6 with radio detections (GRBs 050904 and 090423). We find a jet break at ~ 15 d for GRB 090423, in contrast to pre...

  10. The Afterglow of GRB 130427A from 1 to 10^16 GHz

    CERN Document Server

    Perley, D A; Corsi, A; Tanvir, N R; Levan, A J; Kann, D A; Sonbas, E; Wiersema, K; Zheng, W; Zhao, X -H; Bai, J -M; Chang, L; Clubb, K; Frail, D; Fruchter, A; Göğüş, E; Greiner, J; Güver, T; Horesh, A; Filippenko, A V; Klose, S; Mao, J; Morgan, A N; Schmidl, S; Stecklum, B; Tanga, M; Wang, J -G; Xin, Y -X

    2014-01-01

    We present multiwavelength observations of the afterglow of GRB 130427A, the brightest (in total fluence) gamma-ray burst of the past 29 years. Optical spectroscopy from Gemini-North reveals the redshift of the GRB to be z=0.340, indicating that its unprecedented brightness is primarily the result of its relatively close proximity to Earth; the intrinsic luminosities of both the GRB and its afterglow are not extreme in comparison to other bright GRBs. We present a large suite of multiwavelength observations spanning from 300 s to 60 d after the burst and demonstrate that the afterglow shows relatively simple, smooth evolution at all frequencies with no significant late-time flaring or rebrightening activity. The entire dataset from 1 GHz to 0.1 TeV can be modeled as synchrotron emission from a combination of reverse and forward shocks in good agreement with the standard afterglow model, providing strong support to the applicability of the underlying theory and clarifying the nature of the GeV emission observe...

  11. Radio and X-ray observations of the Ultra-long GRB 150518A

    Science.gov (United States)

    Johnson, Louis; Kamble, Atish; Margutti, Raffaella; Soderberg, Alicia Margarita; Supernova Forensics

    2016-01-01

    Gamma Ray Burst (GRB) 150518A, discovered on 2015 May 18 by the MAXI and KONUS-Wind satellites, lasted for about 1000s, making it an important addition to the recently established class of very long duration GRBs. We report on the JVLA radio observations of the afterglow of GRB 150518A. Additionally, we report the analysis of Xray afterglow observations by Swift-XRT. Multi-band light curves of the radio afterglow display an unusual, conspicuous rise around 10 days after the burst, possibly due to enhanced mass-loss from the progenitor in the final stages of evolution before the GRB. The X-ray afterglow spectrum is significantly soft (photon index Γx > 3) and heavily absorbed (NHx,i > 8 × 10^{21}/cm^2). These properties suggest peculiar behavior that is different from the predictions of the standard fireball model of GRBs. In the light of these properties, we compare different models of progenitors for very long duration GRBs. This work was supported in part by the NSF REU and DoD ASSURE programs under NSF grant no. 1262851 and by the Smithsonian Institution.

  12. Multiwavelength Observations of GRB 110731A: GeV Emission from Onset to Afterglow

    Science.gov (United States)

    Ackermann, M.; Ajello, M.; Asano, K.; Baldini, L.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; Bellazzini, R.; Blandford, R. D.; Bonamente, E.; Borgland, A. W.; Bottacini, E.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Cecchi, C.; Charles, E.; Chaves, R. C. G.; Chekhtman, A.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Conrad, J.; Cutini, S.; D'Ammando, F.; de Angelis, A.; de Palma, F.; Dermer, C. D.; Silva, E. do Couto e.; Drell, P. S.; Drlica-Wagner, A.; Favuzzi, C.; Fegan, S. J.; Focke, W. B.; Franckowiak, A.; Fukazawa, Y.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Giglietto, N.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Granot, J.; Greiner, J.; Grenier, I. A.; Grove, J. E.; Guiriec, S.; Hadasch, D.; Hanabata, Y.; Hayashida, M.; Hays, E.; Hughes, R. E.; Jackson, M. S.; Jogler, T.; Jóhannesson, G.; Johnson, A. S.; Knödlseder, J.; Kocevski, D.; Kuss, M.; Lande, J.; Larsson, S.; Latronico, L.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Mazziotta, M. N.; McEnery, J. E.; Mehault, J.; Mészáros, P.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Monte, C.; Monzani, M. E.; Moretti, E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Naumann-Godo, M.; Norris, J. P.; Nuss, E.; Nymark, T.; Ohno, M.; Ohsugi, T.; Omodei, N.; Orienti, M.; Orlando, E.; Paneque, D.; Perkins, J. S.; Pesce-Rollins, M.; Piron, F.; Pivato, G.; Racusin, J. L.; Rainò, S.; Rando, R.; Razzano, M.; Razzaque, S.; Reimer, A.; Reimer, O.; Romoli, C.; Roth, M.; Ryde, F.; Sanchez, D. A.; Sgrò, C.; Siskind, E. J.; Sonbas, E.; Spinelli, P.; Stamatikos, M.; Takahashi, H.; Tanaka, T.; Thayer, J. G.; Thayer, J. B.; Tibaldo, L.; Tinivella, M.; Tosti, G.; Troja, E.; Usher, T. L.; Vandenbroucke, J.; Vasileiou, V.; Vianello, G.; Vitale, V.; Waite, A. P.; Winer, B. L.; Wood, K. S.; Yang, Z.; Gruber, D.; Bhat, P. N.; Bissaldi, E.; Briggs, M. S.; Burgess, J. M.; Connaughton, V.; Foley, S.; Kippen, R. M.; Kouveliotou, C.; McBreen, S.; McGlynn, S.; Paciesas, W. S.; Pelassa, V.; Preece, R.; Rau, A.; van der Horst, A. J.; von Kienlin, A.; Kann, D. A.; Filgas, R.; Klose, S.; Krühler, T.; Fukui, A.; Sako, T.; Tristram, P. J.; Oates, S. R.; Ukwatta, T. N.; Littlejohns, O.

    2013-02-01

    We report on the multiwavelength observations of the bright, long gamma-ray burst GRB 110731A, by the Fermi and Swift observatories, and by the MOA and GROND optical telescopes. The analysis of the prompt phase reveals that GRB 110731A shares many features with bright Large Area Telescope bursts observed by Fermi during the first three years on-orbit: a light curve with short time variability across the whole energy range during the prompt phase, delayed onset of the emission above 100 MeV, extra power-law component and temporally extended high-energy emission. In addition, this is the first GRB for which simultaneous GeV, X-ray, and optical data are available over multiple epochs beginning just after the trigger time and extending for more than 800 s, allowing temporal and spectral analysis in different epochs that favor emission from the forward shock in a wind-type medium. The observed temporally extended GeV emission is most likely part of the high-energy end of the afterglow emission. Both the single-zone pair transparency constraint for the prompt signal and the spectral and temporal analysis of the forward-shock afterglow emission independently lead to an estimate of the bulk Lorentz factor of the jet Γ ~ 500-550.

  13. Simultaneous optical/gamma-ray observations of GRB 121217's prompt emission

    CERN Document Server

    Elliott, J; Schmidl, S; Greiner, J; Gruber, D; Oates, S; Kobayashi, S; Zhang, B; Cummings, J R; Filgas, R; Gehrels, N; Grupe, D; Kann, D A; Klose, S; Krühler, T; Guelbenzu, A Nicuesa; Rau, A; Rossi, A; Siegel, M; Schady, P; Sudilovsky, V; Tanga, M; Varela, K

    2013-01-01

    Since the advent of the Swift satellite it has been possible to obtain precise localisations of GRB positions of sub-arcsec accuracy within seconds, facilitating ground-based robotic telescopes to automatically slew to the target within seconds. This has yielded a plethora of observational data for the afterglow phase of the GRB, but the quantity of data (<2 keV) covering the initial prompt emission still remains small. Only in a handful of cases has it been possible obtain simultaneous coverage of the prompt emission in a multi-wavelength regime (gamma-ray to optical), as a result of: observing the field by chance prior to the GRB (e.g. 080319B/naked-eye burst), long-prompt emission (e.g., 080928, 110205A) or triggered on a pre-cursor (e.g., 041219A, 050820A, 061121). This small selection of bursts have shown both correlated and uncorrelated gamma-ray and optical light curve behaviour, and the multi-wavelength emission mechanism remains far from resolved (i.e. single population synchrotron self-Component,...

  14. Detailed Afterglow Modeling and Host Galaxy Properties of the Dark GRB 111215A

    CERN Document Server

    van der Horst, A J; Pooley, G G; Wiersema, K; Kruhler, T; Perley, D A; Starling, R L C; Curran, P A; Tanvir, N R; Wijers, R A M J; Strom, R G; Kouveliotou, C; Hartoog, O E; Xu, D; Fynbo, J P U; Jakobsson, P

    2014-01-01

    Gamma-ray burst (GRB) 111215A was bright at X-ray and radio frequencies, but not detected in the optical or near-infrared (nIR) down to deep limits. We have observed the GRB afterglow with the Westerbork Synthesis Radio Telescope and Arcminute Microkelvin Imager at radio frequencies, with the William Herschel Telescope and Nordic Optical Telescope in the nIR/optical, and with the Chandra X-ray Observatory. We have combined our data with the Swift X-Ray Telescope monitoring, and radio and millimeter observations from the literature to perform broadband modeling, and determined the macro- and microphysical parameters of the GRB blast wave. By combining the broadband modeling results with our nIR upper limits we have put constraints on the extinction in the host galaxy. This is consistent with the optical extinction we have derived from the excess X-ray absorption, and higher than in other dark bursts for which similar modeling work has been performed. We also present deep imaging of the host galaxy with the Kec...

  15. The nature of the late achromatic bump in GRB 120326A

    CERN Document Server

    Melandri, A; Guidorzi, C; Bernardini, M G; Kobayashi, S; Mundell, C G; Gomboc, A; Dintinjana, B; Hentunen, V -P; Japelj, J; Kopač, D; Kuroda, D; Morgan, A N; Steele, I A; Quadri, U; Arici, G; Arnold, D; Girelli, R; Hanayama, H; Kawai, N; Mikuž, H; Nissinen, M; Salmi, T; Smith, R J; Strabla, L; Tonincelli, M; Quadri, A

    2014-01-01

    The long ${\\it Swift}$ gamma-ray burst GRB 120326A at redshift $z=1.798$ exhibited a multi-band light curve with a striking feature: a late-time, long-lasting achromatic rebrightening, rarely seen in such events. Peaking in optical and X-ray bands $\\sim 35$ ks ($\\sim 12.5$ ks in the GRB rest frame) after the 70-s GRB prompt burst, the feature brightens nearly two orders of magnitude above the underlying optical power-law decay. Modelling the multiwavelength light curves, we investigate possible causes of the rebrightening in the context of the standard fireball model. We exclude a range of scenarios for the origin of this feature: reverse-shock flash, late-time forward shock peak due to the passage of the maximal synchrotron frequency through the optical band, late central engine optical/X-ray flares, interaction between the expanding blast wave and a density enhancement in the circumburst medium and gravitational microlensing. Instead we conclude that the achromatic rebrightening may be caused by a refreshed...

  16. VizieR Online Data Catalog: List of isolated emission episodes in GRB (Charisi+, 2015)

    Science.gov (United States)

    Charisi, M.; Marka, S.; Bartos, I.

    2015-09-01

    We analysed GRB light curves from the three main GRB catalogues: (i) the Gamma-ray Burst Monitor (GBM) on board Fermi Gamma-ray Space Telescope (Meegan et al., 2009ApJ...702..791M), (ii) the Burst Alert Telescope (BAT) on the Swift satellite (Gehrels et al., 2004ApJ...611.1005G), and (iii) the BATSE on board Compton Gamma-Ray Observatory (Fishman et al., 1989, Its Max'91 Workshop 2: Developments in Observations and Theory for Solar Cycle 22. Wingle R. M., Dennis B. R., editors. 1989. p. 96.). We analysed GRBs detected prior to 2014 January 01. The search was confined to long GRBs with nominal duration T90 (T90>2s), where T90 is defined as the time interval during which 90% of the GRB fluence was detected with 5% fluence detected both before and after the interval. Note that T90 was the only property considered in identifying long GRBs. The main reason for this selection is the reduced accuracy of the search for variability shorter than the bin size of the available light curves. Fermi-GBM consists of 12 NaI detectors, sensitive to energies from 8keV to ~1MeV, which cover the entire unocculted sky, along with two BGO detectors sensitive to higher energy photons (~200keV to ~40MeV). The GBM burst catalogue (http://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html) consists of 1276 GRBs (2008 July-2013 December) and the data are publicly available (http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/) Swift-BAT is a sensitive gamma-ray detector with a wide field of view (1.4sr) designed to provide GRB triggers with accurate localization. During the considered observation period up to the end of 2013 (2004 Decembe-2013 December), Swift had detected 833 GRBs (Sakamoto et al., 2011ApJS..195....2S, Cat. J/ApJS/195/2). The data are retrieved from the public archive (http://swift.gsfc.nasa.gov/archive/) BATSE consisted of eight large NaI area detectors (LADs) covering the energy range of ~25keV to ~2MeV, and was able to observe the entire unobstructed sky. Over its nine

  17. A search for kilonova emission associated with GRB 130603B: the smoking gun signature of a compact binary merger event

    CERN Document Server

    Tanvir, N R; Fruchter, A S; Hjorth, J; Wiersema, K; Tunnicliffe, R; Postigo, A de Ugarte

    2013-01-01

    The nature of short duration gamma-ray bursts (S-GRBs) represents one of the great unsolved mysteries of astrophysics today. While a favoured model for their origin is the merger of two compact objects (e.g., neutron stars) this lacks a smoking gun signature to date. However, these mergers are expected to create radioactive species, including heavy r-process elements, which should result in a faint, fast transient in the days following the burst, a so-called kilonova. Recent calculations suggest much energy comes out in the near-infrared in the days following the initial burst. Here we report a search for such an event accompanying GRB 130603B, the first S-GRB to have a firm redshift established directly from the afterglow. At z=0.36 the faint transient is expected to peak a few days after the burst at an H-band magnitude of ~25. Observing with the Hubble Space Telescope (HST) nine days post-burst, we indeed find a source at the location of the burst, with these properties, although we cannot yet say whether ...

  18. RAPTOR: Closed-Loop monitoring of the night sky and the earliest optical detection of GRB 021211

    Science.gov (United States)

    Vestrand, W. T.; Borozdin, K.; Casperson, D. J.; Fenimore, E.; Galassi, M.; McGowan, K.; Starr, D.; White, R. R.; Wozniak, P.; Wren, J.

    2004-10-01

    We discuss the RAPTOR (Rapid Telescopes for Optical Response) sky monitoring system at Los Alamos National Laboratory. RAPTOR is a fully autonomous robotic system that is designed to identify and make follow-up observations of optical transients with durations as short as one minute. The RAPTOR design is based on Biomimicry of Human Vision. The sky monitor is composed of two identical arrays of telescopes, separated by 38 kilometers, which stereoscopically monitor a field of about 1300 square-degrees for transients. Both monitoring arrays are carried on rapidly slewing mounts and are composed of an ensemble of wide-field telescopes clustered around a more powerful narrow-field telescope called the ``fovea'' telescope. All telescopes are coupled to real-time analysis pipelines that identify candidate transients and relay the information to a central decision unit that filters the candidates to find real celestial transients and command a response. When a celestial transient is found, the system can point the fovea telescopes to any position on the sky within five seconds and begin follow-up observations. RAPTOR also responds to Gamma Ray Burst (GRB) alerts generated by GRB monitoring spacecraft. Here we present RAPTOR observations of GRB 021211 that constitute the earliest detection of optical emission from that event and are the second fastest achieved for any GRB. The detection of bright optical emission from GRB021211, a burst with modest gamma-ray fluence, indicates that prompt optical emission, detectable with small robotic telescopes, is more common than previously thought. Further, the very fast decline of the optical afterglow from GRB 021211 suggests that some so-called ``optically dark'' GRBs were not detected only because of the slow response of the follow-up telescopes.

  19. Localization of Gamma-Ray Bursts Using the Fermi Gamma-Ray Burst Monitor

    Science.gov (United States)

    Connaughton, V.; Briggs, M. S.; Goldstein, A.; Meegan, C. A.; Paciesas, W. S.; Preece, R. D.; Wilson-Hodge, C. A.; Gibby, M. H.; Greiner, J.; Gruber, D.; Jenke, P.; Kippen, R. M.; Pelassa, V.; Xiong, S.; Yu, H.-F.; Bhat, P. N.; Burgess, J. M.; Byrne, D.; Fitzpatrick, G.; Foley, S.; Giles, M. M.; Guiriec, S.; van der Horst, A. J.; von Kienlin, A.; McBreen, S.; McGlynn, S.; Tierney, D.; Zhang, B.-B.

    2015-02-01

    The Fermi Gamma-ray Burst Monitor (GBM) has detected over 1400 gamma-ray bursts (GRBs) since it began science operations in 2008 July. We use a subset of over 300 GRBs localized by instruments such as Swift, the Fermi Large Area Telescope, INTEGRAL, and MAXI, or through triangulations from the InterPlanetary Network, to analyze the accuracy of GBM GRB localizations. We find that the reported statistical uncertainties on GBM localizations, which can be as small as 1°, underestimate the distance of the GBM positions to the true GRB locations and we attribute this to systematic uncertainties. The distribution of systematic uncertainties is well represented (68% confidence level) by a 3.°7 Gaussian with a non-Gaussian tail that contains about 10% of GBM-detected GRBs and extends to approximately 14°. A more complex model suggests that there is a dependence of the systematic uncertainty on the position of the GRB in spacecraft coordinates, with GRBs in the quadrants on the Y axis better localized than those on the X axis.

  20. LOCALIZATION OF GAMMA-RAY BURSTS USING THE FERMI GAMMA-RAY BURST MONITOR

    Energy Technology Data Exchange (ETDEWEB)

    Connaughton, V.; Briggs, M. S.; Burgess, J. M. [CSPAR and Physics Department, University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35899 (United States); Goldstein, A.; Wilson-Hodge, C. A. [Astrophysics Office, ZP12, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Meegan, C. A.; Jenke, P.; Pelassa, V.; Xiong, S.; Bhat, P. N. [CSPAR, University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35899 (United States); Paciesas, W. S. [Universities Space Research Association, Huntsville, AL (United States); Preece, R. D. [Department of Space Science, University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35899 (United States); Gibby, M. H. [Jacobs Technology, Inc., Huntsville, AL (United States); Greiner, J.; Yu, H.-F. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany); Gruber, D. [Planetarium Südtirol, Gummer 5, I-39053 Karneid (Italy); Kippen, R. M. [Los Alamos National Laboratory, NM 87545 (United States); Byrne, D.; Fitzpatrick, G.; Foley, S., E-mail: valerie@nasa.gov [School of Physics, University College Dublin, Belfield, Stillorgan Road, Dublin 4 (Ireland); and others

    2015-02-01

    The Fermi Gamma-ray Burst Monitor (GBM) has detected over 1400 gamma-ray bursts (GRBs) since it began science operations in 2008 July. We use a subset of over 300 GRBs localized by instruments such as Swift, the Fermi Large Area Telescope, INTEGRAL, and MAXI, or through triangulations from the InterPlanetary Network, to analyze the accuracy of GBM GRB localizations. We find that the reported statistical uncertainties on GBM localizations, which can be as small as 1°, underestimate the distance of the GBM positions to the true GRB locations and we attribute this to systematic uncertainties. The distribution of systematic uncertainties is well represented (68% confidence level) by a 3.°7 Gaussian with a non-Gaussian tail that contains about 10% of GBM-detected GRBs and extends to approximately 14°. A more complex model suggests that there is a dependence of the systematic uncertainty on the position of the GRB in spacecraft coordinates, with GRBs in the quadrants on the Y axis better localized than those on the X axis.

  1. Localization of Gamma-Ray Bursts using the Fermi Gamma-Ray Burst Monitor

    CERN Document Server

    Connaughton, V; Goldstein, A; Meegan, C A; Paciesas, W S; Preece, R D; Wilson-Hodge, C A; Gibby, M H; Greiner, J; Gruber, D; Jenke, P; Kippen, R M; Pelassa, V; Xiong, S; Yu, H -F; Bhat, P N; Burgess, J M; Byrne, D; Fitzpatrick, G; Foley, S; Giles, M M; Guiriec, S; van der Horst, A J; von Kienlin, A; McBreen, S; McGlynn, S; Tierney, D; Zhang, B -B

    2014-01-01

    The Fermi Gamma-ray Burst Monitor (GBM) has detected over 1400 Gamma-Ray Bursts (GRBs) since it began science operations in July, 2008. We use a subset of over 300 GRBs localized by instruments such as Swift, the Fermi Large Area Telescope, INTEGRAL, and MAXI, or through triangulations from the InterPlanetary Network (IPN), to analyze the accuracy of GBM GRB localizations. We find that the reported statistical uncertainties on GBM localizations, which can be as small as 1 degree, underestimate the distance of the GBM positions to the true GRB locations and we attribute this to systematic uncertainties. The distribution of systematic uncertainties is well represented (68% confidence level) by a 3.7 degree Gaussian with a non-Gaussian tail that contains about 10% of GBM-detected GRBs and extends to approximately 14 degrees. A more complex model suggests that there is a dependence of the systematic uncertainty on the position of the GRB in spacecraft coordinates, with GRBs in the quadrants on the Y-axis better l...

  2. LOCALIZATION OF GAMMA-RAY BURSTS USING THE FERMI GAMMA-RAY BURST MONITOR

    International Nuclear Information System (INIS)

    The Fermi Gamma-ray Burst Monitor (GBM) has detected over 1400 gamma-ray bursts (GRBs) since it began science operations in 2008 July. We use a subset of over 300 GRBs localized by instruments such as Swift, the Fermi Large Area Telescope, INTEGRAL, and MAXI, or through triangulations from the InterPlanetary Network, to analyze the accuracy of GBM GRB localizations. We find that the reported statistical uncertainties on GBM localizations, which can be as small as 1°, underestimate the distance of the GBM positions to the true GRB locations and we attribute this to systematic uncertainties. The distribution of systematic uncertainties is well represented (68% confidence level) by a 3.°7 Gaussian with a non-Gaussian tail that contains about 10% of GBM-detected GRBs and extends to approximately 14°. A more complex model suggests that there is a dependence of the systematic uncertainty on the position of the GRB in spacecraft coordinates, with GRBs in the quadrants on the Y axis better localized than those on the X axis

  3. ILLUMINATING THE DARKEST GAMMA-RAY BURSTS WITH RADIO OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Zauderer, B. A.; Berger, E.; Margutti, R.; Fong, W.; Laskar, T.; Chornock, R.; Soderberg, A. M. [Department of Astronomy, Harvard University, Cambridge, MA 02138 (United States); Levan, A. J. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Olivares E, F.; Greiner, J. [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Perley, D. A.; Horesh, A.; Carpenter, J. [Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91225 (United States); Updike, A. C. [Department of Chemistry and Physics, Roger Williams University, Bristol, RI 02809 (United States); Tanvir, N. R. [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Menten, K. M. [Max-Planck-Institut fuer Radioastronomie, D-53121 Bonn (Germany); Nakar, E. [Department of Astrophysics, Sackler School of Physics and Astronomy, Tel Aviv University, 69978 Tel Aviv (Israel); Chandra, P. [National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune University Campus, Ganeshkhind, Pune 411007 (India); Castro-Tirado, A. J. [Instituto de Astrofisica de Andalucia (IAA-CSIC), P.O. Box 03004, E-18080 Granada (Spain); Bremer, M. [Institut de Radioastronomie Millimetrique, 300 rue de la Piscine, F-38406 Saint Martin d' Heres (France); and others

    2013-04-20

    We present X-ray, optical, near-infrared (IR), and radio observations of gamma-ray bursts (GRBs) 110709B and 111215A, as well as optical and near-IR observations of their host galaxies. The combination of X-ray detections and deep optical/near-IR limits establish both bursts as ''dark''. Sub-arcsecond positions enabled by radio detections lead to robust host galaxy associations, with optical detections that indicate z {approx}< 4 (110709B) and z Almost-Equal-To 1.8-2.9 (111215A). We therefore conclude that both bursts are dark due to substantial rest-frame extinction. Using the radio and X-ray data for each burst we find that GRB 110709B requires A{sub V}{sup host}{approx}>5.3 mag and GRB 111215A requires A{sub V}{sup host}{approx}>8.5 mag (assuming z = 2). These are among the largest extinction values inferred for dark bursts to date. The two bursts also exhibit large neutral hydrogen column densities of N{sub H,{sub int}} {approx}> 10{sup 22} cm{sup -2} (z = 2) as inferred from their X-ray spectra, in agreement with the trend for dark GRBs. Moreover, the inferred values are in agreement with the Galactic A{sub V} -N{sub H} relation, unlike the bulk of the GRB population. Finally, we find that for both bursts the afterglow emission is best explained by a collimated outflow with a total beaming-corrected energy of E{sub {gamma}} + E{sub K} Almost-Equal-To (7-9) Multiplication-Sign 10{sup 51} erg (z = 2) expanding into a wind medium with a high density, M Almost-Equal-To (6-20) Multiplication-Sign 10{sup -5} M{sub Sun} yr{sup -1} (n Almost-Equal-To 100-350 cm{sup -3} at Almost-Equal-To 10{sup 17} cm). While the energy release is typical of long GRBs, the inferred density may be indicative of larger mass-loss rates for GRB progenitors in dusty (and hence metal rich) environments. This study establishes the critical role of radio observations in demonstrating the origin and properties of dark GRBs. Observations with the JVLA and ALMA will provide a

  4. The bright gamma-ray burst of 2000 February 10: A case study of an optically dark gamma-ray burst

    DEFF Research Database (Denmark)

    Piro, L.; Frail, D.A.; Gorosabel, J.;

    2002-01-01

    The gamma-ray burst GRB 000210 had the highest gamma-ray peak flux of any event localized by BeppoSAX as yet, but it did not have a detected optical afterglow, despite prompt and deep searches down to R-lim approximate to 23.5. It is therefore one of the events recently classified as dark GRBs, w...

  5. THE SECOND SWIFT BURST ALERT TELESCOPE GAMMA-RAY BURST CATALOG

    International Nuclear Information System (INIS)

    We present the second Swift Burst Alert Telescope (BAT) catalog of gamma-ray bursts (GRBs), which contains 476 bursts detected by the BAT between 2004 December 19 and 2009 December 21. This catalog (hereafter the BAT2 catalog) presents burst trigger time, location, 90% error radius, duration, fluence, peak flux, time-averaged spectral parameters, and time-resolved spectral parameters measured by the BAT. In the correlation study of various observed parameters extracted from the BAT prompt emission data, we distinguish among long-duration GRBs (L-GRBs), short-duration GRBs (S-GRBs), and short-duration GRBs with extended emission (S-GRBs with E.E.) to investigate differences in the prompt emission properties. The fraction of L-GRBs, S-GRBs, and S-GRBs with E.E. in the catalog are 89%, 8%, and 2%, respectively. We compare the BAT prompt emission properties with the BATSE, BeppoSAX, and HETE-2 GRB samples. We also correlate the observed prompt emission properties with the redshifts for the GRBs with known redshift. The BAT T90 and T50 durations peak at 70 s and 30 s, respectively. We confirm that the spectra of the BAT S-GRBs are generally harder than those of the L-GRBs. The time-averaged spectra of the BAT S-GRBs with E.E. are similar to those of the L-GRBs. Whereas, the spectra of the initial short spikes of the S-GRBs with E.E. are similar to those of the S-GRBs. We show that the BAT GRB samples are significantly softer than the BATSE bright GRBs and that the time-averaged E obspeak of the BAT GRBs peaks at 80 keV, which is significantly lower energy than those of the BATSE sample, which peak at 320 keV. The time-averaged spectral properties of the BAT GRB sample are similar to those of the HETE-2 GRB samples. By time-resolved spectral analysis, we find that only 10% of the BAT observed photon indices are outside the allowed region of the synchrotron shock model. We see no obvious observed trend in the BAT T90 and the observed spectra with redshifts. The T90 and T

  6. Clustering of galaxies around gamma-ray burst sight-lines

    DEFF Research Database (Denmark)

    Sudilovsky, V.; Greiner, J.; Rau, A.;

    2013-01-01

    There is evidence of an overdensity of strong intervening MgII absorption line systems distributed along the lines of sight toward gamma-ray burst (GRB) afterglows relative to quasar sight-lines. If this excess is real, one should also expect an overdensity of field galaxies around GRB sight......-lines, as strong MgII tends to trace these sources. In this work, we test this expectation by calculating the two point angular correlation function of galaxies within 120'' (~470 h Kpc470h71-1Kpc at z ~ 0.4) of GRB afterglows. We compare the gamma-ray burst optical and near-infrared detector (GROND) GRB...... afterglow sample-one of the largest and most homogeneous samples of GRB fields-with galaxies and active galactic nuclei found in the COSMOS-30 photometric catalog. We find no significant signal of anomalous clustering of galaxies at an estimated median redshift of z ~ 0.3 around GRB sight-lines, down to K...

  7. SEARCH FOR GAMMA-RAYS FROM THE UNUSUALLY BRIGHT GRB 130427A WITH THE HAWC GAMMA-RAY OBSERVATORY

    International Nuclear Information System (INIS)

    The first limits on the prompt emission from the long gamma-ray burst (GRB) 130427A in the >100 GeV energy band are reported. GRB 130427A was the most powerful burst ever detected with a redshift z ≲ 0.5 and featured the longest lasting emission above 100 MeV. The energy spectrum extends at least up to 95 GeV, clearly in the range observable by the High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory, a new extensive air shower detector currently under construction in central Mexico. The burst occurred under unfavorable observation conditions, low in the sky and when HAWC was running 10% of the final detector. Based on the observed light curve at MeV-GeV energies, eight different time periods have been searched for prompt and delayed emission from this GRB. In all cases, no statistically significant excess of counts has been found and upper limits have been placed. It is shown that a similar GRB close to zenith would be easily detected by the full HAWC detector, which will be completed soon. The detection rate of the full HAWC detector may be as high as one to two GRBs per year. A detection could provide important information regarding the high energy processes at work and the observation of a possible cut-off beyond the Fermi Large Area Telescope energy range could be the signature of gamma-ray absorption, either in the GRB or along the line of sight due to the extragalactic background light

  8. SEARCH FOR GAMMA-RAYS FROM THE UNUSUALLY BRIGHT GRB 130427A WITH THE HAWC GAMMA-RAY OBSERVATORY

    Energy Technology Data Exchange (ETDEWEB)

    Abeysekara, A. U. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI (United States); Alfaro, R. [Instituto de Física, Universidad Nacional Autónoma de México, México D. F. (Mexico); Alvarez, C.; Arceo, R. [CEFyMAP, Universidad Autónoma de Chiapas, Tuxtla Gutiérrez, Chiapas (Mexico); Álvarez, J. D.; Arteaga-Velázquez, J. C.; Cotti, U.; De León, C. [Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán (Mexico); Solares, H. A. Ayala [Department of Physics, Michigan Technological University, Houghton, MI (United States); Barber, A. S. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT (United States); Baughman, B. M.; Braun, J. [Department of Physics, University of Maryland, College Park, MD (United States); Bautista-Elivar, N. [Universidad Politécnica de Pachuca, Municipio de Zempoala, Hidalgo (Mexico); BenZvi, S. Y. [Department of Physics and Astronomy, University of Rochester, Rochester, NY (United States); Rosales, M. Bonilla; Carramiñana, A. [Instituto Nacional de Astrofísica, Óptica y Electrónica, Tonantzintla, Puebla (Mexico); Caballero-Mora, K. S. [Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México D. F. (Mexico); Castillo, M.; Cotzomi, J. [Facultad de Ciencias Físico Matemáticas, Benemérita Universidad Autónoma de Puebla, Ciudad Universitaria, Puebla (Mexico); De la Fuente, E., E-mail: dirk.lennarz@gatech.edu [Departamento de Física, Centro Universitario de Ciencias Exactas e Ingenierías, Universidad de Guadalajara, Guadalajara (Mexico); Collaboration: HAWC collaboration; and others

    2015-02-20

    The first limits on the prompt emission from the long gamma-ray burst (GRB) 130427A in the >100 GeV energy band are reported. GRB 130427A was the most powerful burst ever detected with a redshift z ≲ 0.5 and featured the longest lasting emission above 100 MeV. The energy spectrum extends at least up to 95 GeV, clearly in the range observable by the High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory, a new extensive air shower detector currently under construction in central Mexico. The burst occurred under unfavorable observation conditions, low in the sky and when HAWC was running 10% of the final detector. Based on the observed light curve at MeV-GeV energies, eight different time periods have been searched for prompt and delayed emission from this GRB. In all cases, no statistically significant excess of counts has been found and upper limits have been placed. It is shown that a similar GRB close to zenith would be easily detected by the full HAWC detector, which will be completed soon. The detection rate of the full HAWC detector may be as high as one to two GRBs per year. A detection could provide important information regarding the high energy processes at work and the observation of a possible cut-off beyond the Fermi Large Area Telescope energy range could be the signature of gamma-ray absorption, either in the GRB or along the line of sight due to the extragalactic background light.

  9. Effects of Goldstone Bosons on Gamma-Ray Bursts

    CERN Document Server

    Tu, Huitzu

    2015-01-01

    Gamma-ray bursts (GRBs) are the most energetic explosion events in the universe. An amount of gravitational energy of the order of the rest-mass energy of the Sun is released from a small region, within seconds or longer. This should lead to the formation of a fireball of temperature in the MeV range, consisting of electrons/positrons, photons, and a small fraction of baryons. We exploit the potential of GRB fireballs for being a laboratory for testing particle physics beyond the Standard Model, where we find that Weinberg's Higgs portal model serves as a good candidate for this purpose. Due to the resonance effects, the Goldstone bosons can be rapidly produced by electron-positron annihilation process in the initial fireballs of the gamma-ray bursts. On the other hand, the mean free path of the Goldstone bosons is larger than the size of the GRB initial fireballs, so they are not coupled to the GRB's relativistic flow and can lead to significant energy loss. Using generic values for the GRB initial fireball ...

  10. Multi-wavelength observations of afterglow of GRB 080319B and the modeling constraints

    CERN Document Server

    Pandey, S B; Jelínek, M; Kamble, Atish P; Gorosabel, J; Postigo, A de Ugarte; Prins, S; Oreiro, R; Chantry, V; Trushkin, S; Bremer, M; Winters, J M; Pozanenko, A; Krugly, Yu; Slyusarev, I; Kornienko, G; Erofeeva, A; Misra, K; Ramprakash, A N; Mohan, V; Bhattacharya, D; Volnova, A; Plá, J; Ibrahimov, M; Im, M; Volvach, A; Wijers, R A M J

    2009-01-01

    We present observations of the afterglow of GRB 080319B at optical, mm and radio frequencies from a few hours to 67 days after the burst. Present observations along with other published multi-wavelength data have been used to study the light-curves and spectral energy distributions of the burst afterglow. The nature of this brightest cosmic explosion has been explored based on the observed properties and it's comparison with the afterglow models. Our results show that the observed features of the afterglow fits equally good with the Inter Stellar Matter and the Stellar Wind density profiles of the circum-burst medium. In case of both density profiles, location of the maximum synchrotron frequency $\

  11. Gamma Ray Bursts in the HAWC Era

    CERN Document Server

    Mészáros, Peter; Murase, Kohta; Fox, Derek; Gao, He; Senno, Nicholas

    2015-01-01

    Gamma-Ray Bursts are the most energetic explosions in the Universe, and are among the most promising for detecting multiple non-electromagnetic signals, including cosmic rays, high energy neutrinos and gravitational waves. The multi-GeV to TeV gamma-ray range of GRB could have significant contributions from hadronic interactions, mixed with more conventional leptonic contributions. This energy range is important for probing the source physics, including overall energetics, the shock parameters and the Lorentz factor. We discuss some of the latest observational and theoretical developments in the field.

  12. The Birthplaces of Gamma-Ray Bursts

    CERN Document Server

    Young, P A; Young, Patrick A.

    2007-01-01

    We use population synthesis to construct distributions of gamma-ray bursts (GRBs) for different proposed progenitor models. We use a description of star formation that takes into account the evolution of metallicity with redshift and galaxy mass, the evolution of galaxy mass with redshift, and the star formation rate with galaxy mass and redshift. We compare predicted distributions with redshift and metallicity to observations of GRB host galaxies and find that the the simple models cannot produce the observed distributions, but that current theoretical models can reproduce the observations within some constraints on the fraction of fallback black holes that produce GRBs.

  13. Are Gamma-ray Bursts Universal?

    OpenAIRE

    Eichler, David; Levinson, Amir

    2006-01-01

    It is noted that the Liang-Zhang correlation can be accounted for with the viewing angle interpretation proposed earlier. The Ghirlanda correlation, recently generalized by Nava et al (2006) to a wind profile, can be accounted for by the viewing angle interpretation accordingly generalized to a wind profile. Most of the scatter in the spectra and time-integrated brightness in $\\gamma$-ray bursts (GRB) can thus be accounted for by variation in two parameters, 1) the viewing angle and 2) the je...

  14. Selection biases in the gamma ray burst E$_{\\rm iso}$ -- L$_{\\rm opt,X}$ correlation

    CERN Document Server

    Coward, David; Wan, Linfeng; Macpherson, Damien

    2014-01-01

    Gamma ray burst (GRB) optical and X-ray afterglow luminosity is expected to correlate with the GRB isotropic equivalent kinetic energy of the outflow in the standard synchrotron model for GRB afterglows. Previous studies, using prompt GRB isotropic equivalent energy ($E_{\\rm iso}$) as a proxy for isotropic equivalent kinetic energy, have generally confirmed a correlation between X-ray and optical afterglow luminosities. Assuming that GRB afterglow luminosity does not evolve strongly with redshift, we identify a strong Malmquist bias in GRB optical and X-ray afterglow luminosity data. We show that selection effects dominate the observed E$_{\\rm iso}$ -- L$_{\\rm opt,X}$ correlations, and have likely been underestimated in other studies. The bias is strongest for a subset of optically faint bursts $m>24$ at 24 hr with $z>2$. After removing this optical selection bias, the E$_{\\rm iso}$ -- L$_{\\rm opt,X}$ correlation for long GRBs is not statistically significant, but combining both long and short GRB luminosity ...

  15. Search for ultra-high-energy radiation from γ-ray bursts

    International Nuclear Information System (INIS)

    Using data from the CYGNUS extensive air shower array, we have searched for evidence of emission of ultra-high-energy radiation coincident with γ-ray bursts observed by the BATSE instrument on the Compton Gamma-Ray Observatory. No statistically significant excess was found for any point in the sky within 4σ of BATSE's best location coordinates for any of the 56 bursts examined. Furthermore, no events were seen in the 2.2 degree radius circular bin surrounding γ-ray burst GRB 920720, whose location was determined accurately by the Compton/Ulysses/PVO Interplanetary Network of satellites. Flux upper limits depend greatly on the actual zenith angle of the burst. Typical fluence upper limits above 100 TeV are ∼10-6 erg cm-2. The fluence upper limits for GRB 920720 is 2 x 10-6 erg cm-2

  16. Physics of Gamma-Ray Bursts Prompt Emission

    CERN Document Server

    Pe'er, Asaf

    2015-01-01

    In recent years, our understanding of gamma-ray bursts (GRB) prompt emission has been revolutionized, due to a combination of new instruments, new analysis methods and novel ideas. In this review, I describe the most recent observational results and the current theoretical interpretation. Observationally, a major development is the rise of time-resolved spectral analysis. These led to (I) identification of a distinguished high energy component, with GeV photons often seen at a delay; and (II) firm evidence for the existence of a photospheric (thermal) component in a large number of bursts. These results triggered many theoretical efforts aimed at understanding the physical conditions in the inner jet regions from which the prompt photons are emitted, as well as the spectral diversity observed. I highlight some areas of active theoretical research. These include: (I) understanding the role played by magnetic fields in shaping the dynamics of GRB outflow and spectra; (II) understanding the microphysics of kinet...

  17. The warm, the excited, and the molecular gas: GRB 121024A shining through its star-forming galaxy

    CERN Document Server

    Friis, M; Krühler, T; Fynbo, J P U; Ledoux, C; Vreeswijk, P M; Malesani, D; Gorosabel, J; Starling, R L C; Jakobsson, P; Varela, K; Watson, D J; Wiersema, K; Drachmann, A P; Trotter, A; Thöne, C C; Postigo, A de Ugarte; D'Elia, V; Elliott, J; Maturi, M; Goldoni, P; Greiner, J; Haislip, J; Kaper, L; Knust, F; LaCluyze, A; Milvang-Jensen, B; Reichart, D; Schulze, S; Sudilovsky, V; Vergani, S D

    2014-01-01

    We present the first reported case of the simultaneous metallicity determination of a gamma-ray burst (GRB) host galaxy, from both afterglow absorption lines as well as strong emission-line diagnostics. Using spectroscopic and imaging observations of the afterglow and host of the long-duration GRB121024A at z = 2.30, we give one of the most complete views of a GRB host/environment to date. We observe a strong damped Ly-alpha absorber (DLA) with a hydrogen column density of log N(HI) = 21.80+/-0.15, H_2 absorption in the Lyman-Werner bands (molecular fraction of log(f) ~ -1.4; fourth solid detection of molecular hydrogen in a GRB-DLA), the nebular emission lines H-alpha, H-beta, [OII], [OIII] and [NII], as well as a large variety of metal absorption lines. We find a GRB host galaxy that is highly star-forming (SFR ~ 40 Msolar/yr), with a dust-corrected metallicity along the line of sight of [Zn/H]corr = -0.5+/-0.2 ([O/H] ~ -0.3 from emission lines), and a depletion factor of refractory elements of [Zn/Fe] = 0....

  18. Molecular Hydrogen in the Damped Lyman-alpha System towards GRB 120815A at z=2.36

    CERN Document Server

    Krühler, T; Fynbo, J P U; Vreeswijk, P M; Schmidl, S; Malesani, D; Christensen, L; De Cia, A; Hjorth, J; Jakobsson, P; Kann, D A; Kaper, L; Vergani, S D; Afonso, P M J; Covino, S; Postigo, A de Ugarte; D'Elia, V; Filgas, R; Goldoni, P; Greiner, J; Hartoog, O E; Milvang-Jensen, B; Nardini, M; Piranomonte, S; Rossi, A; Sánchez-Ramírez, R; Schady, P; Schulze, S; Sudilovsky, V; Tanvir, N R; Tagliaferri, G; Watson, D J; Wiersema, K; Wijers, R A M J; Xu, D

    2013-01-01

    [Abridged] Molecular hydrogen H_2 is a key requirement for star-formation, frequently observed along sightlines in the Galaxy and to the Magellanic Clouds, but notoriously hard to detect directly beyond z ~ 0. In the DLAs associated with long gamma-ray bursts (GRBs), which are tightly linked to vigorous star-formation, H_2 has remained largely elusive, and has been unequivocally detected only towards GRB 080607 and possibly towards GRB 060206. Here, we present the discovery of H_2-rich gas, including the presence of vibrationally-excited H_2^* in the optical spectrum of the afterglow of GRB 120815A at z=2.36 obtained with X-shooter at the VLT. The galactic environment of GRB 120815A is characterized by a strong DLA with log(N(H)/cm^-2) = 21.95 +/- 0.10, prominent H_2 absorption in the Lyman-Werner bands (log(N(H_2)/cm^-2) = 20.53 +/- 0.04) and thus a molecular gas fraction log f(H_2)=-1.14 +/- 0.10. The distance d between the absorbing neutral gas and GRB 120815A is constrained via photo-excitation modeling o...

  19. Extremely narrow spectrum of GRB110920A: further evidence for localised, subphotospheric dissipation

    CERN Document Server

    Iyyani, S; Ahlgren, B; Burgess, J M; Larsson, J; Pe'er, A; Lundman, C; Axelsson, M; McGlynn, S

    2015-01-01

    Much evidence points towards that the photosphere in the relativistic outflow in GRBs plays an important role in shaping the observed MeV spectrum. However, it is unclear whether the spectrum is fully produced by the photosphere or whether a substantial part of the spectrum is added by processes far above the photosphere. Here we make a detailed study of the $\\gamma-$ray emission from single pulse GRB110920A which has a spectrum that becomes extremely narrow towards the end of the burst. We show that the emission can be interpreted as Comptonisation of thermal photons by cold electrons in an unmagnetised outflow at an optical depth of $\\tau \\sim 20$. The electrons receive their energy by a local dissipation occurring close to the saturation radius. The main spectral component of GRB110920A and its evolution is thus, in this interpretation, fully explained by the emission from the photosphere including localised dissipation at high optical depths.

  20. The synchrotron-self-Compton radiation accompanying shallow decaying X-ray afterglow: the case of GRB 940217

    CERN Document Server

    Wei, Da-Ming

    2008-01-01

    High energy emission (> tens MeV) of Gamma-Ray Bursts (GRBs) provides an important clue to understand the physical processes involved in GRBs, which may be correlated with the GRB early afterglow. A shallow decline phase has been well detected in about half {\\it Swift} Gamma-ray Burst X-ray afterglows. The widely considered interpretation involves a significant energy injection and possibly time-evolving shock parameter(s). This work we calculate the synchrotron-self-Compton (SSC) radiation of such an external forward shock and show that it could explain the well-known long term high energy (i.e., tens MeV to GeV) afterglow of GRB 940217. We propose that the cooperation of Swift and GLAST will help to reveal the nature of GRBs.

  1. The Synchrotron-self-Compton Radiation Accompanying Shallow Decaying X-Ray Afterglow: the Case of GRB 940217

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    High energy emission (> tens MeV) of Gamma-Ray Bursts (GRBs) provides an important clue on the physical processes occurring in GRBs that may be correlated with the GRB early afterglow. A shallow decline phase has been well identified in about half of Swift Gamma-ray Burst X-ray afterglows. The widely considered interpretation involves a significant energy injection and possibly time-evolving shock parameter(s). We calculate the synchrotron-self-Compton (SSC) radiation of such an external forward shock and show that it could explain the well-known long term high energy (i.e., tens MeV to GeV) afterglow of GRB 940217. We propose that cooperation of Swift and GLAST will help to reveal the nature of GRBs.

  2. An inverse Compton origin for the 55 GeV photon in the late afterglow of GRB 130907A

    CERN Document Server

    Tang, Qing-Wen; Wang, Xiang-Yu

    2014-01-01

    The extended high-energy gamma-ray (>100 MeV) emission which occurs well after the prompt gamma-ray bursts (GRBs) is usually explained as the afterglow synchrotron radiation. Here we report the analysis of the Fermi Large Area Telescope observations of GRB 130907A. A 55 GeV photon compatible with the position of the burst was found at about 5 hours after the prompt phase. The probability that this photon is associated with GRB 130907A is higher than 99.96%. The energy of this photon exceeds the maximum synchrotron photon energy at this time and its occurrence thus challenges the synchrotron mechanism as the origin for the extended high-energy >10 GeV emission. Modeling of the broad-band spectral energy distribution suggests that such high energy photons can be produced by the synchrotron self-Compton emission of the afterglow.

  3. The Internal-Collision-Induced Magnetic Reconnection and Turbulence (ICMART) Model of Gamma-Ray Bursts

    CERN Document Server

    Zhang, Bing

    2010-01-01

    The recent Fermi observation of GRB 080916C shows that the bright photosphere emission associated with a putative fireball is missing, which suggests a Poynting-flux-dominated outflow. We propose a model of gamma-ray burst (GRB) prompt emission in the Poynting-flux-dominated regime, namely, the Internal-Collision-induced MAgnetic Reconnection and Turbulence (ICMART) model. It is envisaged that the GRB central engine launches an intermittent, magnetically-dominated wind, and that in the GRB emission region, the ejecta is still moderately magnetized. Similar to the internal shock (IS) model, the mini-shells interact internally at the traditional internal shock radius. Most of these early collision have little energy dissipation, but serve to distort the ordered magnetic field lines. At a certain point, the distortion of magnetic field configuration reaches the critical condition to allow fast reconnection seeds to occur, which induce relativistic MHD turbulence in the interaction regions. The turbulence further...

  4. Feasibility of a Small, Rapid Optical-to-IR Response, Next Generation Gamma Ray Burst Mission

    CERN Document Server

    Grossan, B; Bogomolov, V V; Svertilov, S I; Vedenkin, N N; Panasyuk, M; Goncharov, B; Rozhkov, G; Saleev, K; Grobovskoj, E; Krasnov, A S; Morozenko, V S; Osedlo, V I; Rogkov, E; Vachenko, T V; Linder, E V

    2013-01-01

    We present motivations for and study feasibility of a small, rapid optical to IR response gamma ray burst (GRB) space observatory. By analyzing existing GRB data, we give realistic detection rates for X-ray and optical/IR instruments of modest size under actual flight conditions. Given new capabilities of fast optical/IR response (about 1 s to target) and simultaneous multi-band imaging, such an observatory can have a reasonable event rate, likely leading to new science. Requiring a Swift-like orbit, duty cycle, and observing constraints, a Swift-BAT scaled down to 190 square cm of detector area would still detect and locate about 27 GRB per yr. for a trigger threshold of 6.5 sigma. About 23 percent of X-ray located GRB would be detected optically for a 10 cm diameter instrument (about 6 per yr. for the 6.5 sigma X-ray trigger).

  5. FERMI DETECTION OF DELAYED GeV EMISSION FROM THE SHORT GAMMA-RAY BURST 081024B

    International Nuclear Information System (INIS)

    We report on the detailed analysis of the high-energy extended emission from the short gamma-ray burst (GRB) 081024B detected by the Fermi Gamma-ray Space Telescope. Historically, this represents the first clear detection of temporal extended emission from a short GRB. The light curve observed by the Fermi Gamma-ray Burst Monitor lasts approximately 0.8 s whereas the emission in the Fermi Large Area Telescope lasts for about 3 s. Evidence of longer lasting high-energy emission associated with long bursts has been already reported by previous experiments. Our observations, together with the earlier reported study of the bright short GRB 090510, indicate similarities in the high-energy emission of short and long GRBs and open the path to new interpretations.

  6. The Radio Afterglows of Gamma-Ray Bursts

    CERN Document Server

    Frail, D A

    2003-01-01

    Radio afterglow studies have become an integral part of the study of gamma-ray bursts, providing complementary and sometimes unique diagnostics on GRB explosions, their progenitors, and their environments. This brief review consists of two parts. The first section is a summary of current search strategies and the main observational properties of radio afterglows. In the second section we highlight the key scientific contributions made by radio observations, either alone or as part of panchromatic studies.

  7. The Swift Gamma-Ray Burst Host Galaxy Legacy Survey - I. Sample Selection and Redshift Distribution

    OpenAIRE

    Perley, D. A.; Krühler, T.; Schulze, S.; De Ugarte Postigo, A.; Hjorth, J.; Berger, E.; Cenko, S. B.; Chary, R.; Cucchiara, A.; Ellis, R; Fong, W.; Fynbo, J. P. U.; J. Gorosabel; Greiner, J.; Jakobsson, P.

    2015-01-01

    We introduce the Swift Gamma-Ray Burst Host Galaxy Legacy Survey ("SHOALS"), a multi-observatory high-redshift galaxy survey targeting the largest unbiased sample of long-duration gamma-ray burst (GRB) hosts yet assembled (119 in total). We describe the motivations of the survey and the development of our selection criteria, including an assessment of the impact of various observability metrics on the success rate of afterglow-based redshift measurement. We briefly outline our host galaxy obs...

  8. Detailed afterglow modelling and host galaxy properties of the dark GRB 111215A

    Science.gov (United States)

    van der Horst, A. J.; Levan, A. J.; Pooley, G. G.; Wiersema, K.; Krühler, T.; Perley, D. A.; Starling, R. L. C.; Curran, P. A.; Tanvir, N. R.; Wijers, R. A. M. J.; Strom, R. G.; Kouveliotou, C.; Hartoog, O. E.; Xu, D.; Fynbo, J. P. U.; Jakobsson, P.

    2015-02-01

    Gamma-ray burst (GRB) 111215A was bright at X-ray and radio frequencies, but not detected in the optical or near-infrared (nIR) down to deep limits. We have observed the GRB afterglow with the Westerbork Synthesis Radio Telescope and Arcminute Microkelvin Imager at radio frequencies, with the William Herschel Telescope and Nordic Optical Telescope in the nIR/optical, and with the Chandra X-ray Observatory. We have combined our data with the Swift X-Ray Telescope monitoring, and radio and millimetre observations from the literature to perform broad-band modelling, and determined the macro- and microphysical parameters of the GRB blast wave. By combining the broad-band modelling results with our nIR upper limits we have put constraints on the extinction in the host galaxy. This is consistent with the optical extinction we have derived from the excess X-ray absorption, and higher than in other dark bursts for which similar modelling work has been performed. We also present deep imaging of the host galaxy with the Keck I telescope, Spitzer Space Telescope, and Hubble Space Telescope (HST), which resulted in a well-constrained photometric redshift, giving credence to the tentative spectroscopic redshift we obtained with the Keck II telescope, and estimates for the stellar mass and star formation rate of the host. Finally, our high-resolution HST images of the host galaxy show that the GRB afterglow position is offset from the brightest regions of the host galaxy, in contrast to studies of optically bright GRBs.

  9. Swift: A Gamma Ray Bursts Explorer

    Science.gov (United States)

    Gehrels, Neil

    2003-01-01

    Swift is a NASA gamma-ray burst MIDEX mission that is in development for launch in December 2003. It is a multiwavelength transient observatory for GRB astronomy. The goals of the mission are to determine the origin of GRBs and their afterglows and use bursts to probe the early Universe. It will also.perform a survey of the hard X-ray sky to a sensitivity level of -1 mCrab. A wide-field camera will detect more than a hundred GRBs per year to 5 times fainter than BATSE. Sensitive narrow-field X-ray and UV/optical telescopes will be pointed at the burst location in 20 to 70 sec by an autonomously controlled 'swift' spacecraft. For each burst, arcsec positions will be determined and optical/UV/X-ray/gamma-ray spectrophotometry performed. Measurements of redshift will be made for many of the bursts. The instrumentation is a combination of superb existing flight-spare hardware and design from XMM and Spectrum-X/JET-X contributed by collaborators in the UK and Italy and development of a coded-aperture camera with a large-area (approximately 0.5 square meter) CdZnTe detector array. The hardware is currently in final stages of fabrication and initial stages of integration and test. Key components of the mission are vigorous follow-up and outreach programs to engage the astronomical community and public in Swift.

  10. The Cosmic Gamma-Ray Bursts

    CERN Document Server

    Djorgovski, S G; Kulkarni, S R; Sari, R; Bloom, J S; Galama, T J; Harrison, F A; Price, P A; Fox, D; Reichart, D; Yost, S; Berger, E; Diercks, A H; Goodrich, R; Chaffee, F H

    2001-01-01

    Cosmic gamma-ray bursts are one of the great frontiers of astrophysics today. They are a playground of relativists and observers alike. They may teach us about the death of stars and the birth of black holes, the physics in extreme conditions, and help us probe star formation in the distant and obscured universe. In this review we summarise some of the remarkable progress in this field over the past few years. While the nature of the GRB progenitors is still unsettled, it now appears likely that at least some bursts originate in explosions of very massive stars, or at least occur in or near the regions of massive star formation. The physics of the burst afterglows is reasonably well understood, and has been tested and confirmed very well by the observations. Bursts are found to be beamed, but with a broad range of jet opening angles; the mean gamma-ray energies after the beaming corrections are ~ 10^51 erg. Bursts are associated with faint ~ 25 mag) galaxies at cosmological redshifts, with ~ 1. The host gal...

  11. GRB 060117: Reverse + forward shock solution

    CERN Document Server

    Jel'inek, M; Kubánek, P; Hudec, R; Nekola, M F; Rídky, J; Grygar, J; Jel\\'inek, Martin; Prouza, Michael; Kub\\'anek, Petr; Hudec, Ren\\'e; Nekola, Martin F.; Ridky, Jan; Grygar, Jiri

    2007-01-01

    We present a discovery and observation of an extraordinarily bright prompt optical emission of the GRB 060117 obtained by a wide-field camera atop the robotic telescope FRAM of the Pierre Auger Observatory from 2 to 10 minutes after the GRB. We found rapid average temporal flux decay of alpha = -1.7 +/- 0.1 and a peak brightness R = 10.1 mag. We interpret the shape of the lightcurve as a transition between reverse and forward shock emission.

  12. Very Large Telescope/Ultraviolet and Visual Echelle Spectrograph and FORS2 spectroscopy of the GRB 081008 afterglow

    Science.gov (United States)

    D'Elia, V.; Campana, S.; Covino, S.; D'Avanzo, P.; Piranomonte, S.; Tagliaferri, G.

    2011-11-01

    We aim at studying the gamma-ray burst (GRB), GRB 081008, environment by analysing the spectra of its optical afterglow. Ultraviolet and Visual Echelle Spectrograph/Very Large Telescope (UVES/VLT) high-resolution spectroscopy of GRB 081008 was secured ˜5 h after the Swift-BAT trigger. Our data set also comprises three VLT/FORS2 nearly simultaneous spectra of the same source. The availability of nearly simultaneous high- and low-resolution spectra for a GRB afterglow is an extremely rare event. The GRB-damped Lyman α system at z= 1.9683 shows that the interstellar medium (ISM) of the host galaxy is constituted by at least three components which contribute to the line profiles. Component I is the redmost one, and is 20 and 78 km s-1 redward components II and III, respectively. We detect several ground state and excited absorption features in components I and II. These features have been used to compute the distances between the GRB and the absorbers. Component I is found to be 52 ± 6 pc away from the GRB, while component II presents few excited transitions and its distance is 200+60- 80 pc. Component III only features a few, low-ionization and saturated lines suggesting that it is even farther from the GRB. Component I represents the closest absorber ever detected near a GRB. This (relatively) low distance can possibly be a consequence of a dense GRB environment, which prevents the GRB prompt/afterglow emission to strongly affect the ISM up to higher distances. The hydrogen column density associated with GRB 081008 is log NH/cm-2= 21.11 ± 0.10, and the metallicity of the host galaxy is in the range of [X/H] =-1.29 to -0.52. In particular, we found [Fe/H] =-1.19 ± 0.11 and [Zn/H] =-0.52 ± 0.11 with respect to solar values. This discrepancy can be explained by the presence of dust in the GRB ISM, given the opposite refractory properties of iron and zinc. By deriving the depletion pattern for GRB 081008, we find the optical extinction in the visual band to be AV

  13. The origin of the plateau and late rebrightening in the afterglow of GRB 120326A

    International Nuclear Information System (INIS)

    GRB 120326A is an unusual gamma-ray burst (GRB) that has a long plateau and a very late rebrightening in both X-ray and optical bands. The similar behavior of the optical and X-ray light curves suggests that they may share a common origin. The long plateau starts at several hundred seconds and ends at tens of thousands of seconds, and the peak time of the late rebrightening is about 30,000 s. We analyze the energy injection model by means of numerical and analytical solutions, considering both the wind environment and the interstellar medium environment for GRB afterglows. We particularly study the influence of the injection starting time, ending time, stellar wind density (or density of the circumburst environment), and injection luminosity on the shape of the afterglow light curves, respectively. In the wind model, we find that the light curve is largely affected by the parameters and that there is a 'bump' in the late stage. In the wind environment, we found that the longer the energy is injected, the more obvious the rebrightening will be. We also find that the peak time of the bump is determined by the stellar wind density. We use the late continuous injection model to interpret the unusual afterglow of GRB 120326A. The model fits the observational data well; however, we find that the timescale of the injection must be higher than 10,000 s, which implies that the timescale of the central engine activity must also be more than 10,000 s. This information can give useful constraints on the central engines of GRBs—we consider a newborn millisecond pulsar with a strong magnetic field to be the central engine. On the other hand, our results suggest that the circumburst environment of GRB 120326A is very likely a stellar wind.

  14. MODELING THE GRB HOST GALAXY MASS DISTRIBUTION: ARE GRBs UNBIASED TRACERS OF STAR FORMATION?

    International Nuclear Information System (INIS)

    We model the mass distribution of long gamma-ray burst (GRB) host galaxies given recent results suggesting that GRBs occur in low-metallicity environments. By utilizing measurements of the redshift evolution of the mass-metallicity relationship for galaxies, along with a sharp host metallicity cutoff suggested by Modjaz and collaborators, we estimate an upper limit on the stellar mass of a galaxy that can efficiently produce a GRB as a function of redshift. By employing consistent abundance indicators, we find that subsolar metallicity cutoffs effectively limit GRBs to low-stellar mass spirals and dwarf galaxies at low redshift. At higher redshifts, as the average metallicity of galaxies in the Universe falls, the mass range of galaxies capable of hosting a GRB broadens, with an upper bound approaching the mass of even the largest spiral galaxies. We compare these predicted limits to the growing number of published GRB host masses and find that extremely low-metallicity cutoffs of 0.1 to 0.5 Zsun are effectively ruled out by a large number of intermediate mass galaxies at low redshift. A mass function that includes a smooth decrease in the efficiency of producing GRBs in galaxies of metallicity above 12+log(O/H)KK04 = 8.7 can, however, accommodate a majority of the measured host galaxy masses. We find that at z ∼ 1, the peak in the observed GRB host mass distribution is inconsistent with the expected peak in the mass of galaxies harboring most of the star formation. This suggests that GRBs are metallicity-biased tracers of star formation at low and intermediate redshifts, although our model predicts that this bias should disappear at higher redshifts due to the evolving metallicity content of the universe.

  15. Modeling The GRB Host Galaxy Mass Distribution: Are GRBs Unbiased Tracers of Star Formation?

    Energy Technology Data Exchange (ETDEWEB)

    Kocevski, Daniel; /KIPAC, Menlo Park; West, Andrew A.; /UC, Berkeley, Astron. Dept. /MIT, MKI; Modjaz, Maryam; /UC, Berkeley, Astron. Dept.

    2009-08-03

    We model the mass distribution of long gamma-ray burst (GRB) host galaxies given recent results suggesting that GRBs occur in low metallicity environments. By utilizing measurements of the redshift evolution of the mass-metallicity (M-Z) relationship for galaxies, along with a sharp host metallicity cut-off suggested by Modjaz and collaborators, we estimate an upper limit on the stellar mass of a galaxy that can efficiently produce a GRB as a function of redshift. By employing consistent abundance indicators, we find that sub-solar metallicity cut-offs effectively limit GRBs to low stellar mass spirals and dwarf galaxies at low redshift. At higher redshifts, as the average metallicity of galaxies in the Universe falls, the mass range of galaxies capable of hosting a GRB broadens, with an upper bound approaching the mass of even the largest spiral galaxies. We compare these predicted limits to the growing number of published GRB host masses and find that extremely low metallicity cut-offs of 0.1 to 0.5 Z{sub {circle_dot}} are effectively ruled out by a large number of intermediate mass galaxies at low redshift. A mass function that includes a smooth decrease in the efficiency of producing GRBs in galaxies of metallicity above 12+log(O/H){sub KK04} = 8.7 can, however, accommodate a majority of the measured host galaxy masses. We find that at z {approx} 1, the peak in the observed GRB host mass distribution is inconsistent with the expected peak in the mass of galaxies harboring most of the star formation. This suggests that GRBs are metallicity biased tracers of star formation at low and intermediate redshifts, although our model predicts that this bias should disappear at higher redshifts due to the evolving metallicity content of the universe.

  16. The origin of the plateau and late rebrightening in the afterglow of GRB 120326A

    Energy Technology Data Exchange (ETDEWEB)

    Hou, S. J.; Lu, J. F. [Department of Astronomy and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, Fujian 361005 (China); Geng, J. J.; Wang, K.; Huang, Y. F.; Dai, Z. G. [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Wu, X. F., E-mail: xfwu@pmo.ac.cn [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

    2014-04-20

    GRB 120326A is an unusual gamma-ray burst (GRB) that has a long plateau and a very late rebrightening in both X-ray and optical bands. The similar behavior of the optical and X-ray light curves suggests that they may share a common origin. The long plateau starts at several hundred seconds and ends at tens of thousands of seconds, and the peak time of the late rebrightening is about 30,000 s. We analyze the energy injection model by means of numerical and analytical solutions, considering both the wind environment and the interstellar medium environment for GRB afterglows. We particularly study the influence of the injection starting time, ending time, stellar wind density (or density of the circumburst environment), and injection luminosity on the shape of the afterglow light curves, respectively. In the wind model, we find that the light curve is largely affected by the parameters and that there is a 'bump' in the late stage. In the wind environment, we found that the longer the energy is injected, the more obvious the rebrightening will be. We also find that the peak time of the bump is determined by the stellar wind density. We use the late continuous injection model to interpret the unusual afterglow of GRB 120326A. The model fits the observational data well; however, we find that the timescale of the injection must be higher than 10,000 s, which implies that the timescale of the central engine activity must also be more than 10,000 s. This information can give useful constraints on the central engines of GRBs—we consider a newborn millisecond pulsar with a strong magnetic field to be the central engine. On the other hand, our results suggest that the circumburst environment of GRB 120326A is very likely a stellar wind.

  17. Observing a Burst with Sunglasses

    Science.gov (United States)

    2003-11-01

    Unique Five-Week VLT Study of the Polarisation of a Gamma-Ray Burst Afterglow "Gamma-ray bursts (GRBs)" are certainly amongst the most dramatic events known in astrophysics. These short flashes of energetic gamma-rays, first detected in the late 1960's by military satellites, last from less than one second to several minutes. GRBs have been found to be situated at extremely large ("cosmological") distances. The energy released in a few seconds during such an event is larger than that of the Sun during its entire lifetime of more than 10,000 million years. The GRBs are indeed the most powerful events since the Big Bang known in the Universe, cf. ESO PR 08/99 and ESO PR 20/00. During the past years circumstantial evidence has mounted that GRBs signal the collapse of extremely massive stars, the so-called hypernovae. This was finally demonstrated some months ago when astronomers, using the FORS instrument on ESO's Very Large Telescope (VLT), documented in unprecedented detail the changes in the spectrum of the light source ("the optical afterglow") of the gamma-ray burst GRB 030329 (cf. ESO PR 16/03). A conclusive and direct link between cosmological gamma-ray bursts and explosions of very massive stars was provided on this occasion. Gamma-Ray Burst GRB 030329 was discovered on March 29, 2003 by NASA's High Energy Transient Explorer spacecraft. Follow-up observations with the UVES spectrograph at the 8.2-m VLT KUEYEN telescope at the Paranal Observatory (Chile) showed the burst to have a redshift of 0.1685 [1]. This corresponds to a distance of about 2,650 million light-years, making GRB 030329 the second-nearest long-duration GRB ever detected. The proximity of GRB 030329 resulted in very bright afterglow emission, permitting the most extensive follow-up observations of any afterglow to date. A team of astronomers [2] led by Jochen Greiner of the Max-Planck-Institut für extraterrestrische Physik (Germany) decided to make use of this unique opportunity to study the

  18. Dark Gamma-Ray Bursts in the Swift Era

    International Nuclear Information System (INIS)

    We propose a new method for the classification of optically dark gamma-ray bursts (GRBs), based on the X-ray and optical-to-X-ray spectral indices of GRB afterglows, and utilizing the spectral capabilities of Swift. This method depends less on model assumptions than previous methods, and can be used as a quick diagnostic tool to identify optically sub-luminous bursts. With this method we can also find GRBs that are extremely bright at optical wavelengths. We show that the previously suggested correlation between the optical darkness and the X-ray/gamma-ray brightness is merely an observational selection effect.

  19. Varying Faces of Photospheric Emission in Gamma-Ray Bursts

    CERN Document Server

    Axelsson, M

    2015-01-01

    Among the more than 1000 gamma-ray bursts observed by the Fermi Gamma-ray Space Telescope, a large fraction show narrow and hard spectra inconsistent with non-thermal emission, signifying optically thick emission from the photosphere. However, only a few of these bursts have spectra consistent with a pure Planck function. We will discuss the observational features of photospheric emission in these GRBs as well as in the ones showing multi-component spectra. We interpret the observations in light of models of subphotospheric dissipation, geometrical broadening and multi-zone emission, and show what we can learn about the dissipation mechanism and properties of GRB jets.

  20. Gamma-Ray Bursts and Population III Stars

    Science.gov (United States)

    Toma, Kenji; Yoon, Sung-Chul; Bromm, Volker

    2016-04-01

    Gamma-ray bursts (GRBs) are ideal probes of the epoch of the first stars and galaxies. We review the recent theoretical understanding of the formation and evolution of the first (so-called Population III) stars, in light of their viability of providing GRB progenitors. We proceed to discuss possible unique observational signatures of such bursts, based on the current formation scenario of long GRBs. These include signatures related to the prompt emission mechanism, as well as to the afterglow radiation, where the surrounding intergalactic medium might imprint a telltale absorption spectrum. We emphasize important remaining uncertainties in our emerging theoretical framework.

  1. Using STIS to find $\\gamma$-Ray Burst Redshifts

    CERN Document Server

    Bloom, J S; Wijers, R A M J; Almaini, O; Tanvir, N R; Johnson, R A; Bloom, Joshua S.; Sigurdsson, Steinn; Wijers, Ralph A. M. J.; Almaini, Omar; Tanvir, Nial R.; Johnson, Rachel A.

    1997-01-01

    A recent spectrum of the optical afterglow of GRB 970508 suggests that gamma-ray bursts (GRBs) are cosmological in origin and it is of crucial importance to derive an accurate distance to each burst. If GRBs occur near their host galaxies then Lyman limit absorption should be observable in roughly half the GRB afterglow spectra. Here we outline the methodology to obtain a redshift from the GRB afterglow spectrum using the recently installed Space Telescope Imaging Spectrograph (STIS) instrument onboard the Hubble Space Telescope. A low-resolution spectrum with the Multi-Anode Microchannel Array (MAMA) detector gives complete spectral coverage over the wavelength range 157.0-318.0 nm (Near UV) and 115.0-174.0 nm (Far UV). Assuming a Target of Opportunity observation is conducted soon (< 3 weeks) after a bright burst, a relatively small integration time (about 3 orbits) would be sufficient to detect the Lyman limit over a wide redshift range (0.3 < z < 2.2). Detection (or non-detection) of the Lyman li...

  2. Are GRB Blackbodies an Artifact of Spectral Evolution?

    CERN Document Server

    Burgess, J Michael

    2014-01-01

    The analysis of gamma-ray burst (GRB) spectra with multi-component emission models has become an important part of the field. In particular, multi-component analysis where one component is a blackbody representing emission from a photosphere has enabled both a more detailed understanding of the energy content of the jet as well as the ability to examine the dynamic structure of the outflow. While the existence of a blackbody-like component has been shown to be significant and not a byproduct of background fluctuations, it is very possible that it can be an artifact of spectral evolution of a single component that is being poorly resolved in time. Herein, this possibility is tested by simulating a single component evolving in time and then folding the spectra through the $Fermi$ detector response to generate time-tagged event Gamma-ray Burst Monitor (GBM) data. We then fit both the time integrated and resolved generated spectral data with a multi-component model using standard tools. It is found that in {\\it t...

  3. The SEDs and Host Galaxies of the dustiest GRB afterglows

    CERN Document Server

    Krühler, T; Schady, P; Savaglio, S; Afonso, P M J; Clemens, C; Elliott, J; Filgas, R; Gruber, D; Kann, D A; Klose, S; Küpcü-Yoldas, A; McBreen, S; E., F Olivares; Pierini, D; Rau, A; Rossi, A; Nardini, M; Guelbenzu, A Nicuesa; Sudilovsky, V; Updike, A C

    2011-01-01

    (Abridged) Until recently the information inferred from gamma-ray burst follow-up observations was mostly limited to optically bright afterglows, biasing all demographic studies against sight-lines that contain large amounts of dust. Here, we present GRB afterglow and host observations for a sample of bursts that are exemplary of previously missed ones because of high visual extinction along the sight-line. This facilitates an investigation of the properties, geometry and location of the absorbing dust of these poorly-explored host galaxies, and a comparison to hosts from optically-selected samples. The hosts of the dustiest afterglows are diverse in their properties, but on average redder, more luminous and massive than the hosts of optically-bright events. We hence probe a different galaxy population, suggesting that previous host samples miss most of the massive, chemically-evolved and metal-rich members. This also indicates that the dust along the sight-line is often related to host properties, and thus p...

  4. First hours of the GRB 030329 optical afterglow

    CERN Document Server

    Burenin, R A; Pavlinsky, M N; Denissenko, D V; Terekhov, O V; Tkachenko, A V; Aslan, Z; Khamitov, I; Uluc, K; Alpar, M A; Kiziloglu, U; Baykal, A; Bikmaev, I; Sakhibullin, N A; Suleymanov, V

    2003-01-01

    We present the first results of the observations of the extremely bright optical afterglow of gamma-ray burst (GRB) 030329 with the 1.5m Russian-Turkish telescope RTT150 (TUBITAK National Observatory, Bakyrlytepe, Turkey). RTT150 was one of the first 1.5m-class telescopes pointed to the afterglow. Observations were started approximately 6 hours after the burst. During the first 5 hours of our observations the afterglow faded exactly as a power law with index -1.19+-0.01 in each of the BVRI Bessel filters. After that, in all BVRI filters simultaneously we observe a steepening of the power law light curve. The power law decay index smoothly approaches the value ~= -1.9, observed by other observatories later. This power law break occurs at t-t_0 =0.57 days and lasts for +-0.1 days. We observe no variability above the gradual fading with the upper limits 10--1% on time scales 0.1--1000s. Spectral flux distribution in four BVRI filters corresponds to the power law spectrum with spectral index \\alpha=0.66+-0.01. Th...

  5. ISO detection of a 60 micron source near GRB970508

    CERN Document Server

    Hanlon, L O; Metcalfe, L; McBreen, B; Altieri, B; Castro-Tirado, A J; Claret, A; Costa, E; Delaney, M; Feroci, M; Frontera, F; Galama, T J; Gorosabel, J; Groot, P J; Heise, J; Kessler, M F; Kouveliotou, C; Palazzi, E; Van Paradijs, J; Piro, L; Smith, N

    2000-01-01

    The Infrared Space Observatory observed the field of the $\\gamma$--ray burst GRB 970508 with the CAM and PHT instruments on May 21 and 24, 1997 and with PHT in three filters in November 1997. A source at 60 $\\mu$m (flux in May of $66\\pm 10$ mJy) was detected near the position of the host galaxy of this $\\gamma$--ray burst. The source was detected again in November 1997, at a marginally lower flux ($43\\pm 13$ mJy). A Galactic cirrus origin and a stellar origin for the emission can be ruled out on the basis of the infrared colours. The marginal evidence for variability in the 60 $\\mu$m flux between May and November is not sufficient to warrant interpretation of the source as transient fireball emission. However, the infrared colours are physically reasonable if attributed to conventional dust emission from a single blackbody source. The probability of detecting a 60 $\\mu$m by chance in a PHT beam down to a detection limit of 50 mJy is $\\sim 5\\times 10^{-3}$. If the source is at the redshift of the host galaxy o...

  6. Estimates for Lorentz factors of gamma-ray bursts from early optical afterglow observations

    CERN Document Server

    Hascoet, R; Daigne, F; Mochkovitch, R

    2013-01-01

    The peak time of optical afterglow may be used as a proxy to constrain the Lorentz factor Gamma of the gamma-ray burst (GRB) ejecta. We revisit this method by including bursts with optical observations that started when the afterglow flux was already decaying; these bursts can provide useful lower limits on Gamma. Combining all analyzed bursts in our sample, we find that the previously reported correlation between Gamma and the burst luminosity L_gamma does not hold. However, the data clearly shows a lower bound Gamma_min which increases with L_gamma. We suggest an explanation for this feature: explosions with large jet luminosities and Gamma < Gamma_min suffer strong adiabatic cooling before their radiation is released at the photosphere; they produce weak bursts, barely detectable with present instruments. To test this explanation we examine the effect of adiabatic cooling on the GRB location in the L_gamma - Gamma plane using a Monte Carlo simulation of the GRB population. Our results predict detectable...

  7. Ultra-Fast Flash Observatory (uffo) for Observation of Early Photons from Gamma Ray Bursts

    DEFF Research Database (Denmark)

    Park, I. H.; Ahmad, S.; Barrillon, P.;

    2013-01-01

    of the burst mechanism, shock breakouts in core-collapse supernovae, tidal disruptions around black holes, test Lorentz violation, be the electromagnetic counterpart to neutrino and gravitational wave signatures of the violent universe, and verify the prospect of GRB as a new standard candle...

  8. Ultra-Fast Flash Observatory for observation of early photons from gamma ray bursts

    DEFF Research Database (Denmark)

    Park, I. H.; Ahmad, S.; Barrillon, P.;

    2012-01-01

    We describe the space project of Ultra-Fast Flash Observatory (UFFO) which will observe early optical photons from gamma-ray bursts (GRBs) with a sub-second optical response, for the first time. The UFFO will probe the early optical rise of GRBs, opening a completely new frontier in GRB and trans...

  9. Dust extinction in high-z galaxies with gamma-ray burst afterglow spectroscopy

    DEFF Research Database (Denmark)

    Elíasdóttir, Á.; Fynbo, J. P. U.; Hjorth, J.;

    2009-01-01

    We report the clear detection of the 2175 Å dust absorption feature in the optical afterglow spectrum of the gamma-ray burst (GRB) GRB 070802 at a redshift of z = 2.45. This is the highest redshift for a detected 2175 Å dust bump to date, and it is the first clear detection of the 2175 Å bump in ...

  10. Ultra High Energy Neutrinos from Gamma-Ray Burst Afterglows Using the Swift-UVOT Data

    CERN Document Server

    Nir, Guy; Landsman, Hagar; Behar, Ehud

    2015-01-01

    We consider a sample of 107 Gamma Ray Bursts (GRBs) for which early UV emission was measured by Swift, and extrapolate the photon intensity to lower energies. Protons accelerated in the GRB jet may interact with such photons to produce charged pions and subsequently ultra high energy neutrinos $\\varepsilon_\

  11. EDGE: Explorer of diffuse emission and gamma-ray burst explosions

    DEFF Research Database (Denmark)

    Piro, L; den Herder, J W; Ohashi, T;

    2009-01-01

    How structures of various scales formed and evolved from the early Universe up to present time is a fundamental question of astrophysical cosmology. EDGE (Piro et al., 2007) will trace the cosmic history of the baryons from the early generations of massive stars by Gamma-Ray Burst (GRB) explosions...

  12. EDGE: Explorer of diffuse emission and gamma-ray burst explosions

    DEFF Research Database (Denmark)

    Den Herder, J.W.; Hermsen, W.; Hoevers, H.;

    2007-01-01

    How structures of various scales formed and evolved from the early Universe up to present time is a fundamental question of astrophysics. EDGE1 will trace the cosmic history of the baryons from the early generations of massive stars by Gamma-Ray Burst (GRB) explosions, through the period of galaxy...

  13. An achromatic break in the afterglow of the short GRB 140903A: evidence for a narrow jet

    OpenAIRE

    Troja, E.; Sakamoto, T.; Cenko, S. B.; Lien, A.; Gehrels, N.; Castro-Tirado, A. J.; Ricci, R.; Capone, J.; Toy, V.; Kutyrev, A.; Kawai, N.; Cucchiara, A.; Fruchter, A.; Gorosabel, J.; Jeong, S.

    2016-01-01

    We report the results of our observing campaign on GRB140903A, a nearby (z=0.351) short duration (T90~0.3 s) gamma-ray burst discovered by Swift. We monitored the X-ray afterglow with Chandra up to 21 days after the burst, and detected a steeper decay of the X-ray flux after approximately 1 day. Continued monitoring at optical and radio wavelengths showed a similar decay in flux at nearly the same time, and we interpret it as evidence of a narrowly collimated jet. By using the standard fireba...

  14. The host of GRB/XRF 030528 - an actively star forming galaxy at z=0.782

    CERN Document Server

    Rau, A

    2005-01-01

    An important parameter for the distinction of X-ray flashes, X-ray rich bursts and Gamma-ray bursts in the rest frame is the distance to the explosion site. Here we report on the spectroscopic redshift determination of the host galaxy of XRF/GRB 030528 using the ESO VLT FORS2 instrument. From the strong oxygen and hydrogen emission lines the redshift was measured to be z=0.782+-0.001. Obtaining the line luminosities and ratios we find that the host is consistent with being an actively star forming galaxy with sub-solar metallicity. With a stellar mass of ~10E10 Msun the host is placed among the most massive GRB host galaxies at a similar redshift. Estimating the redshifted properties of the prompt emission, we find that XRF/GRB 030528 would be classified as an X-ray rich bursts in the rest frame rather than an X-ray flash in the typically used observer frame.

  15. The First Swift BAT Gamma-Ray Burst Catalog

    Science.gov (United States)

    Sakamoto, T.; Barthelmy, S. D.; Barbier, L.; Cummings, J. R.; Fenimore, E. E.; Gehrels, N.; Hullinger, D.; Krimm, H. A.; Markwardt, C. B.; Palmer, D. M.; Parsons, A. M.; Sato, G.; Stamatikos, M.; Tueller, J.; Ukwatta, T. N.; Zhang, B.

    2007-01-01

    We present the first Swift Burst Alert Telescope (BAT) catalog of gamma ray bursts (GRBs), which contains bursts detected by the BAT between 2004 December 19 and 2007 June 16. This catalog (hereafter BAT1 catalog) contains burst trigger time, location, 90% error radius, duration, fluence, peak flux, and time averaged spectral parameters for each of 237 GRBs, as measured by the BAT. The BAT-determined position reported here is within 1.75' of the Swift X-ray Telescope (XRT)-determined position for 90% of these GRBs. The BAT T(sub 90) and T(sub 50) durations peak at 80 and 20 seconds, respectively. From the fluence-fluence correlation, we conclude that about 60% of the observed peak energies, E(sup obs)(sub peak) of BAT GRBs could be less than 100 keV. We confirm that GRB fluence to hardness and GRB peak flux to hardness are correlated for BAT bursts in analogous ways to previous missions' results. The correlation between the photon index in a simple power-law model and E(sup obs)(sub peak) is also confirmed. We also report the current status for the on-orbit BAT calibrations based on observations of the Crab Nebula.

  16. Alternative temporal classification of long Gamma Ray Bursts

    Science.gov (United States)

    Alejandro Vasquez, Nicolas; Baquero, Andres; Andrade, David

    2015-08-01

    In order to increase the understanding on Gamma Ray Bursts, many attempts of classification have been proposed. Starting with the canonical classification into long and short GRBs, alternative classifications taking into account the cosmological origin of GRBs have been analyzed. In the present work we propose an alternative classification based on two temporal estimators, the Auto Correlation Function (ACF) of the light curves and the emission time which considered the time where the bursts engine is active. The time estimators chosen reflects the internal evolution of the GRB and the internal structure. Using a sample of 61 bright GRBs detected by SWIFT satellite with known redshift, we proposed a bimodal distribution of long bursts. The two types of bursts have different internal structure suggesting different progenitors.

  17. Solving the missing GRB neutrinos and the GRB-SN puzzles

    CERN Document Server

    Fargion, Daniele

    2016-01-01

    We argue that any GRB model where the progenitor is made by high relativistic hadronic interactions shock waves, and later on by electron-pairs feeding gamma jets, is necessarily leading to an average high neutrino over photon fluency ratio well above unity, mostly above several thousands. The present observed average highest energy ICECUBE neutrino energy fluency is at most comparable to the gamma-X in GRB one. Therefore no hadronic GRB, Fireball or even any earliest hadronic thin precessing Jet, may fit the observation. We therefore imagine a novel electronic thin spinning and precessing jet, fed in late binary system, able to avoid the overcrowded neutrino tails foreseen in hadronic GRB models. In some occasion such an electronic model may lead to an explosion that shines during a GRB with an (apparent) late SN-like event.

  18. GRB/GW Association: Long–Short GRB Candidates, Time Lag, Measuring Gravitational Wave Velocity, and Testing Einstein’s Equivalence Principle

    Science.gov (United States)

    Li, Xiang; Hu, Yi-Ming; Fan, Yi-Zhong; Wei, Da-Ming

    2016-08-01

    Short-duration gamma-ray bursts (SGRBs) are widely believed to be powered by the mergers of compact binaries, such as binary neutron stars or possibly neutron star–black hole binaries. Though the prospect of detecting SGRBs with gravitational wave (GW) signals by the advanced Laser Interferometer Gravitational-Wave Observatory (LIGO)/VIRGO network is promising, no known SGRB has been found within the expected advanced LIGO/VIRGO sensitivity range for binary neutron star systems. We find, however, that the two long–short GRBs (GRB 060505 and GRB 060614) may be within the horizon of advanced GW detectors. In the upcoming era of GW astronomy, the merger origin of some long–short GRBs, as favored by the macronova signature displayed in GRB 060614, can be unambiguously tested. The model-dependent time lags between the merger and the onset of the prompt emission of the GRB are estimated. The comparison of such time lags between model predictions and the real data expected in the era of the GW astronomy would be helpful in revealing the physical processes taking place at the central engine (including the launch of the relativistic outflow, the emergence of the outflow from the dense material ejected during the merger, and the radiation of gamma rays). We also show that the speed of GWs, with or without a simultaneous test of Einstein’s equivalence principle, can be directly measured to an accuracy of ∼ 3× {10}-8 {cm} {{{s}}}-1 or even better in the advanced LIGO/VIRGO era.

  19. The optically unbiased GRB host (TOUGH) survey. VI. Radio observations at z<1 and consistency with typical star-forming galaxies

    CERN Document Server

    Michałowski, Michał J; Hjorth, J; Malesani, D; Reinfrank, R F; Bonavera, L; Cerón, J M Castro; Ibar, E; Dunlop, J S; Fynbo, J P U; Garrett, M A; Jakobsson, P; Kaplan, D L; Krühler, T; Levan, A J; Massardi, M; Pal, S; Sollerman, J; Tanvir, N R; van der Horst, A J; Watson, D; Wiersema, K

    2012-01-01

    The objective of this paper is to determine the level of obscured star formation activity and dust attenuation in a sample of gamma-ray burst (GRB) hosts; and to test the hypothesis that GRB hosts have properties consistent with those of the general star-forming galaxy populations. We present a radio continuum survey of all z 500 Mo yr^-1. For the undetected hosts the mean radio flux (<35 uJy 3sigma) corresponds to an average SFR < 15 Mo yr^-1. Moreover, ~92% of the z<1 GRB hosts have ultraviolet dust attenuation A_UV < 6.7 mag (visual attenuation A_V < 3 mag). Hence we did not find evidence for large dust obscuration in a majority of GRB hosts. Finally, we found that the distributions of SFRs and A_UV of GRB hosts are consistent with those of Lyman break galaxies, Halpha emitters at similar redshifts and of galaxies from cosmological simulations. The similarity of the GRB population with other star-forming galaxies is consistent with the hypothesis that GRBs, a least at z<1, trace a large f...

  20. The Cosmic Gamma-Ray Bursts

    Science.gov (United States)

    Djorgovski, S. G.; Frail, D. A.; Kulkarni, S. R.; Sari, R.; Bloom, J. S.; Galama, T. J.; Harrison, F. A.; Price, P. A.; Fox, D.; Reichart, D. E.; Yost, S.; Berger, E.; Diercks, A.; Goodrich, R.; Chaffee, F.

    2002-12-01

    Cosmic γ-ray bursts are one of the great frontiers of astrophysics today. They are a playground of relativists and observers alike. They may teach us about the death of stars and the birth of black holes, the physics in extreme conditions, and help us probe star formation in the distant and obscured universe. In this review we summarise some of the remarkable progress in this field over the past few years. While the nature of the GRB progenitors is still unsettled, it now appears likely that at least some bursts originate in explosions of very massive stars, or at least occur in or near the regions of massive star formation. The physics of the burst afterglows is reasonably well understood, and has been tested and confirmed very well by the observations. Bursts are found to be beamed, but with a broad range of jet opening angles; the mean γ-ray energies after the beaming corrections are ~ 1051 erg. Bursts are associated with faint ( ~ 25 mag) galaxies at cosmological redshifts, with ~ 1. The host galaxies span a range of luminosities and morphologies, but appear to be broadly typical for the normal, actively star-forming galaxy populations at comparable redshifts and magnitudes. Some of the challenges for the future include: the nature of the short bursts and possibly other types of bursts and transients; use of GRBs to probe the obscured star formation in the universe, and possibly as probes of the very early universe; and their detection as sources of high-energy particles and gravitational waves.