BAT2 GRB Catalog - Prompt Emission Properties of Swift GRBs

International Nuclear Information System (INIS)

Sakamoto, T.; Barthelmy, S.; Gehrels, N.; Parsons, A.; Tueller, J.; Baumgartner, W.; Cummings, J.; Fenimore, E.; Palmer, D.; Krimm, H.; Markwardt, C.; Sato, G.; Stamatikos, M.; Ukwatta, T.

2010-01-01

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 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. The BAT T 90 duration peaks at 70 s. We confirm that the spectra of the BAT short-duration GRBs are generally harder than those of the long-duration GRBs. The observed durations of the BAT high redshift GRBs are not systematically longer than those of the moderate redshift GRBs. Furthermore, the observed spectra of the BAT high redshift GRBs are similar to or harder than the moderate redshift GRBs.

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

International Nuclear Information System (INIS)

Abdo, A. A.; Ackermann, M.; Bechtol, K.; Berenji, B.; Bloom, E. D.; Borgland, A. W.; Bouvier, A.; Asano, K.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Bellazzini, R.; Bregeon, J.; Ballet, J.; Band, D. L.; Barbiellini, G.; Bastieri, D.; Bhat, P. N.; Bissaldi, E.; Bonamente, E.

2009-01-01

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.

Study of GRBs Hosts Galaxies Vicinity Properties

Science.gov (United States)

Bernal, S.; Vasquez, N.; Hoyle, F.

2017-07-01

The study of GRBs host galaxies and its vicinity could provide constrains on the progenitor and an opportunity to use these violent explosions to characterize the nature of the highredshift universe. Studies of GRB host galaxies reveal a population of starforming galaxies with great diversity, spanning a wide range of masses, star formation rate, and redshifts. In order to study the galactic ambient of GRBs we used the S. Savaglio catalog from 2015 where 245 GRBs are listed with RA-Dec position and z. We choose 22 GRBs Hosts galaxies from Savaglio catalog and SDSS DR12, with z range 0population characteristics. We calculate the volumetric density populatation of glalaxies around the GRB Hosts within a volume of an sphere whit radius of 10 h-1 Mpc and find a low density compared with a typical group of galaxies. In order to know the galaxies stellar formation state, in regions where GRBs are formed, we made an analysis of color index using SDSS data of μ [λ 3543], r[λ 6231] and calculate the indexes μ-r. We find a value μ-r=2.63, it means that the galactic ambient of GRBs Host regions are statistically redder than void and wall regions on a indirect way (Voids:μ-r=2.043; Walls:μ-r=2.162). Futhermore, we used a inverse concentration index analysis, ICI=R50/R90 and find that galaxies in GRBs Hosts vicinity are also of slightly early type than void and wall galaxies. With this work we provide characteristics on the regions for future works related with highredsift universe that using the GRBs.

GRBs optical follow-up observation at Lunin observatory, Taiwan

Energy Technology Data Exchange (ETDEWEB)

Huang, K.Y.; Ip, W.H. [Chung-Li Univ., Taiwan (China). Institute of astronomy; Urata, Y. [RIKEN, Saitama (Japan); Tokyo Institute of Technology, Tokyo (Japan). Department of Physics; Tamagawa, T.; Onda, K. [RIKEN, Saitama (Japan); Makishima, K. [RIKEN, Saitama (Japan); Tokyo Univ., Tokyo (Japan). Department of Physics

2005-07-15

The Lulin GRB program, using the Lulin One-meter Telescope (LOT) in Taiwan started in July 2003. Its scientific aims are to discover optical counterparts of XRFs and short and long GRBs, then to quickly observe them in multiple bands. Thirteen follow-up observations were provided by LOT between July 2003 and Feb. 2005. One host galaxy was found at GRB 031203. Two optical afterglows were detected for GRB 040924 and GRB 041006. In addition, the optical observations of GRB 031203 and a discussion of the non-detection of the optical afterglow of GRB 031203 are also reported in this article.

GRBs optical follow-up observation at Lunin observatory, Taiwan

International Nuclear Information System (INIS)

Huang, K.Y.; Ip, W.H.; Makishima, K.; Tokyo Univ., Tokyo

2005-01-01

The Lulin GRB program, using the Lulin One-meter Telescope (LOT) in Taiwan started in July 2003. Its scientific aims are to discover optical counterparts of XRFs and short and long GRBs, then to quickly observe them in multiple bands. Thirteen follow-up observations were provided by LOT between July 2003 and Feb. 2005. One host galaxy was found at GRB 031203. Two optical afterglows were detected for GRB 040924 and GRB 041006. In addition, the optical observations of GRB 031203 and a discussion of the non-detection of the optical afterglow of GRB 031203 are also reported in this article

GRB 090727 AND GAMMA-RAY BURSTS WITH EARLY-TIME OPTICAL EMISSION

International Nuclear Information System (INIS)

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

2013-01-01

We present a multi-wavelength analysis of Swift 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 process. 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 behavior, and notice a rich diversity of spectral properties. Using a simple internal shock dissipation model, we show that the emission during prompt GRB phase can occur at very different frequencies via synchrotron radiation. Based on the results obtained from observations and simulation, we conclude that the standard external shock interpretation for early-time optical emission is disfavored in most cases due to sharp peaks (Δt/t < 1) and steep rise/decay indices, and that internal dissipation can explain the properties of GRBs with optical peaks during gamma-ray emission

Radioactive decay of the late-time light curves of GRB-SNe

Science.gov (United States)

Misra, Kuntal; Fruchte, Andrew Steven

2018-04-01

We present the late-time Hubble Space Telescope observations of two GRB associated supernovae, GRB 030329/SN 2003dh and XRF 060218/SN 2006aj. Using the multi-color data upto ˜ 320 days after the burst, we constrain the late-time decay nature of these supernovae. The decay rates of SN 2003dh are steeper than SN 2006aj. A comparison with two other GRB supernovae, GRB 980425/SN 1998bw and the supernova associated with XRF 020903, shows that the decay rates of SN 2003dh are similar to XRF 020903 and those of SN 2006aj are similar to SN 1998bw. The late-time decay rates are steeper than the 56Co?56Fe radioactive decay rate (0.0098 mag day-1) indicating that there is some leakage of gamma-rays.

GRB 111005A at z = 0.0133 and the Prospect of Establishing Long-Short GRB/GW Association

Science.gov (United States)

Wang, Yuan-Zhu; Huang, Yong-Jia; Liang, Yun-Feng; Li, Xiang; Jin, Zhi-Ping; Zhang, Fu-Wen; Zou, Yuan-Chuan; Fan, Yi-Zhong; Wei, Da-Ming

2017-12-01

GRB 111005A, a long-duration gamma-ray burst (GRB) that occurred within a metal-rich environment that lacks massive stars with {M}{ZAMS}≥slant 15 {M}⊙ , is not coincident with supernova emission down to a stringent limit and thus should be classified as a “long-short” GRB (lsGRB; also known as an SN-less long GRB or hybrid GRB), like GRB 060505 and GRB 060614. In this work, we show that in the neutron star merger model the non-detection of the optical/infrared emission of GRB 111005A requires sub-relativistic neutron-rich ejecta with a mass of ≤slant 0.01 {M}⊙ , which is (significantly) less massive than that of GRB 130603B, GRB 060614, GRB 050709, and GRB 170817A. The lsGRBs are found to have a high rate density and the neutron star merger origin model can be unambiguously tested by the joint observations of the second-generation gravitational-wave (GW) detectors and the full-sky gamma-ray monitors such as Fermi-GBM and the proposed GECAM. If no lsGRB/GW association is observed in the 2020s, alternative scenarios have to be systematically investigated. With the detailed environmental information achievable for the nearby events, a novel kind of merger or explosion origin may be identified.

The GLAST Mission, LAT and GRBs

International Nuclear Information System (INIS)

Omodei, Nicola; INFN, Pisa

2006-01-01

The GLAST Large Area Telescope (LAT) is the next generation satellite experiment for high-energy gamma-ray astronomy. It is a pair conversion telescope built with a plastic anticoincidence shield, a segmented CsI electromagnetic calorimeter, and the largest silicon strip tracker ever built. It will cover the energy range from 30 MeV to 300 GeV, shedding light on many issues left open by its predecessor EGRET. One of the most exciting science topics is the detection and observation of gamma-ray bursts (GRBs). In this paper we present the work done so far by the GRB LAT science group in studying the performance of the LAT detector to observe GRBs.We report on the simulation framework developed by the group as well as on the science tools dedicated to GRBs data analysis. We present the LAT sensitivity to GRBs obtained with such simulations, and, finally, the general scheme of GRBs detection that will be adopted on orbit

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....

The optical afterglow of the short gamma-ray burst GRB 050709.

Science.gov (United States)

Hjorth, Jens; Watson, Darach; Fynbo, Johan P U; Price, Paul A; Jensen, Brian L; Jørgensen, Uffe G; Kubas, Daniel; Gorosabel, Javier; Jakobsson, Páll; Sollerman, Jesper; Pedersen, Kristian; Kouveliotou, Chryssa

2005-10-06

It has long been known that there are two classes of gamma-ray bursts (GRBs), mainly distinguished by their durations. The breakthrough in our understanding of long-duration GRBs (those lasting more than approximately 2 s), which ultimately linked them with energetic type Ic supernovae, came from the discovery of their long-lived X-ray and optical 'afterglows', when precise and rapid localizations of the sources could finally be obtained. X-ray localizations have recently become available for short (duration burst: GRB 050709. The optical afterglow was localized with subarcsecond accuracy, and lies in the outskirts of a blue dwarf galaxy. The optical and X-ray afterglow properties 34 h after the GRB are reminiscent of the afterglows of long GRBs, which are attributable to synchrotron emission from ultrarelativistic ejecta. We did not, however, detect a supernova, as found in most nearby long GRB afterglows, which suggests a different origin for the short GRBs.

Relativistic Hydrodynamics and Spectral Evolution of GRB Jets

Science.gov (United States)

Cuesta-Martínez, C.

2017-09-01

In this thesis we study the progenitor systems of long gamma-ray bursts (GRBs) using numerical models of their dynamics and the electromagnetic emission. Of all the possible classes of events, we focus on those showing a prominent component of thermal emission, which might be generated due to the interaction of a relativistic jet with the medium into which it is propagating. The main part of the thesis is devoted to modelling GRBs from two different clases of progenitors: ultra-long GRBs dominated by blackbody emission and GRBs associated with core-collapse supernovae (SNe). The study of GRB jets and their radiative emission has been basically divided into two steps. First, the dynamical evolution of relativistic jets can be simulated by means of multidimensional special relativistic hydrodynamic simulations which have been performed with the MRGENESIS code. Second, the synthetic emission from such jets is computed with the relativistic radiative transfer code SPEV in a post-processing stage assuming different radiative processes in which we follow the temporal and spectral evolution of the emitted radiation. An instrumental part of this project consisted in extending SPEV to include thermal processes, such as thermal bremsstrahlung, in order to account for the thermal signal that may arise in some GRBs. In the first part of this thesis, we extend an existing theoretical model to explain the class of blackbody-dominated GRBs (BBD-GRBs), i.e., long lasting events characterized by the presence of a notable thermal component trailing the GRB prompt emission, and a rather weak traditional afterglow. GRB 101225A, the "Christmas burst", is the most prominent member of this class. It has been suggested that BBD-GRBs could result from the merger of a binary system formed by a neutron star and the Helium core of an evolved, massive star. We model in 2D the propagation of ultrarelativistic jets through the environments created by such mergers. We outline the most relevant

Gamma-ray Burst Formation Environment: Comparison of Redshift Distributions of GRB Afterglows

Directory of Open Access Journals (Sweden)

Sung-Eun Kim

2005-12-01

Full Text Available Since gamma-ray bursts(GRBs have been first known to science societites in 1973, many scientists are involved in their studies. Observations of GRB afterglows provide us with much information on the environment in which the observed GRBs are born. Study of GRB afterglows deals with longer timescale emissions in lower energy bands (e.g., months or even up to years than prompt emissions in gamma-rays. Not all the bursts accompany afterglows in whole ranges of wavelengths. It has been suggested as a reason for that, for instance, that radio and/or X-ray afterglows are not recorded mainly due to lower sensitivity of detectors, and optical afterglows due to extinctions in intergalactic media or self-extinctions within a host galaxy itself. Based on the idea that these facts may also provide information on the GRB environment, we analyze statistical properties of GRB afterglows. We first select samples of the redshift-known GRBs according to the wavelength of afterglow they accompanied. We then compare their distributions as a function of redshift, using statistical methods. As a results, we find that the distribution of the GRBs with X-ray afterglows is consistent with that of the GRBs with optical afterglows. We, therefore, conclude that the lower detection rate of optical afterglows is not due to extinctions in intergalactic media.

CONSTRAINING THE GRB-MAGNETAR MODEL BY MEANS OF THE GALACTIC PULSAR POPULATION

Energy Technology Data Exchange (ETDEWEB)

Rea, N. [Anton Pannekoek Institute for Astronomy, University of Amsterdam, Postbus 94249, NL-1090 GE Amsterdam (Netherlands); Gullón, M.; Pons, J. A.; Miralles, J. A. [Departament de Fisica Aplicada, Universitat d’Alacant, Ap. Correus 99, E-03080 Alacant (Spain); Perna, R. [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States); Dainotti, M. G. [Physics Department, Stanford University, Via Pueblo Mall 382, Stanford, CA (United States); Torres, D. F. [Instituto de Ciencias de l’Espacio (ICE, CSIC-IEEC), Campus UAB, Carrer Can Magrans s/n, E-08193 Barcelona (Spain)

2015-11-10

A large fraction of Gamma-ray bursts (GRBs) displays an X-ray plateau phase within <10{sup 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 2005 January and 2014 August. 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 or rate at z = 0). Direct consequences would be that we should allow the existence of magnetars and “super-magnetars” having different progenitors, and that Type Ib/c SNe related to Long GRBs form systematically neutron stars with higher initial magnetic fields. We put an upper limit of ≤16 “super-magnetars” formed by a GRB in our Galaxy in the past Myr (at 99% c.l.). This limit is somewhat smaller than what is roughly expected from Long GRB rates, although the very large uncertainties do not allow us to draw strong conclusion in this respect.

Pair creation by very high-energy photons in gamma-ray bursts a unified picture for the energetics of GRBs

CERN Document Server

Totani, T

1999-01-01

The extreme energetics of the gamma-ray burst (GRB) 990123 have revealed that some GRBs emit quite a large amount of energy, and the total energy release from GRBs seems to change from burst to burst by a factor of 10/sup 2/-10/sup $9 3/ as E/sub gamma , iso/~10/sup 52-55/ erg, where E/sub gamma , iso/ is the observed GRB energy when the radiation is isotropic. If all GRBs are triggered by similar events, such a wide dispersion in energy release seems odd. The $9 author proposes a unified picture for the energetics of GRBs, in which all GRB events release roughly the same amount of energy E/sub iso/~10 /sup 55-56/ erg relativistic motion, with the baryon load problem almost resolved. A mild $9 dispersion in the initial Lorentz factor ( Gamma ) results in a difference of E/sub gamma , iso/ by up to a factor of m/sub p//m/sub e/~10/sup 3/. Protons work as `a hidden energy reservoir' of the total GRB energy, and E/sub gamma , $9 iso/ depends on the energy transfer efficiency from protons into electrons (or posit...

A new gamma-ray burst classification scheme from GRB 060614.

Science.gov (United States)

Gehrels, N; Norris, J P; Barthelmy, S D; 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

2006-12-21

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

A novel explosive process is required for the gamma-ray burst GRB 060614.

Science.gov (United States)

Gal-Yam, A; Fox, D B; Price, P A; Ofek, E O; Davis, M R; Leonard, D C; Soderberg, A M; Schmidt, B P; Lewis, K M; Peterson, B A; Kulkarni, S R; Berger, E; Cenko, S B; Sari, R; Sharon, K; Frail, D; Moon, D-S; Brown, P J; Cucchiara, A; Harrison, F; Piran, T; Persson, S E; McCarthy, P J; Penprase, B E; Chevalier, R A; MacFadyen, A I

2006-12-21

Over the past decade, our physical understanding of gamma-ray bursts (GRBs) has progressed rapidly, thanks to the discovery and observation of their long-lived afterglow emission. Long-duration (> 2 s) GRBs are associated with the explosive deaths of massive stars ('collapsars', ref. 1), which produce accompanying supernovae; the short-duration (< or = 2 s) GRBs have a different origin, which has been argued to be the merger of two compact objects. Here we report optical observations of GRB 060614 (duration approximately 100 s, ref. 10) that rule out the presence of an associated supernova. This would seem to require a new explosive process: either a massive collapsar that powers a GRB without any associated supernova, or a new type of 'engine', as long-lived as the collapsar but without a massive star. We also show that the properties of the host galaxy (redshift z = 0.125) distinguish it from other long-duration GRB hosts and suggest that an entirely new type of GRB progenitor may be required.

Afterglow Population Studies from Swift Follow-Up Observations of Fermi LAT GRBs

Science.gov (United States)

Racusin, Judith L.; Oates, S. R.; McEnery, J.; Vasileiou, V.; Troja, E.; Gehrels, N.

2010-01-01

The small population of Fermi LAT detected GRBs discovered over the last year has been providing interesting and unexpected clues into GRB prompt and afterglow emission mechanisms. Over the last 5 years, it has been Swift that has provided the robust data set of UV/optical and X-ray afterglow observations that opened many windows into other components of GRB emission structure. We explore the new ability to utilize both of these observatories to study the same GRBs over 10 orders of magnitude in energy, although not always concurrently. Almost all LAT GRBs that have been followed-up by Swift within 1-day have been clearly detected and carefully observed. We will present the context of the lower-energy afterglows of this special subset of GRBs that has > 100 MeV emission compared to the hundreds in the Swift database that may or may not have been observed by LAT, and theorize upon the relationship between these properties and the origin of the high energy gamma-ray emission.

Time resolved spectroscopy of GRB 030501 using INTEGRAL

DEFF Research Database (Denmark)

Beckmann, V.; Borkowski, J.; Courvoisier, T.J.L.

2003-01-01

The gamma-ray instruments on-board INTEGRAL offer an unique opportunity to perform time resolved analysis on GRBs. The imager IBIS allows accurate positioning of GRBs and broad band spectral analysis, while SPI provides high resolution spectroscopy. GRB 030501 was discovered by the INTEGRAL Burst...... the Ulysses and RHESSI experiments....

Awakening the BALROG: BAyesian Location Reconstruction Of GRBs

Science.gov (United States)

Burgess, J. Michael; Yu, Hoi-Fung; Greiner, Jochen; Mortlock, Daniel J.

2018-05-01

The accurate spatial location of gamma-ray bursts (GRBs) is crucial for both accurately characterizing their spectra and follow-up observations by other instruments. The Fermi Gamma-ray Burst Monitor (GBM) has the largest field of view for detecting GRBs as it views the entire unocculted sky, but as a non-imaging instrument it relies on the relative count rates observed in each of its 14 detectors to localize transients. Improving its ability to accurately locate GRBs and other transients is vital to the paradigm of multimessenger astronomy, including the electromagnetic follow-up of gravitational wave signals. Here we present the BAyesian Location Reconstruction Of GRBs (BALROG) method for localizing and characterizing GBM transients. Our approach eliminates the systematics of previous approaches by simultaneously fitting for the location and spectrum of a source. It also correctly incorporates the uncertainties in the location of a transient into the spectral parameters and produces reliable positional uncertainties for both well-localized sources and those for which the GBM data cannot effectively constrain the position. While computationally expensive, BALROG can be implemented to enable quick follow-up of all GBM transient signals. Also, we identify possible response problems that require attention and caution when using standard, public GBM detector response matrices. Finally, we examine the effects of including the uncertainty in location on the spectral parameters of GRB 080916C. We find that spectral parameters change and no extra components are required when these effects are included in contrast to when we use a fixed location. This finding has the potential to alter both the GRB spectral catalogues and the reported spectral composition of some well-known GRBs.

On the X-ray lines in the afterglows of GRBs

CERN Document Server

Dar, Arnon; De Rújula, Alvaro; Dar, Arnon; Dado, Shlomo

2003-01-01

The observation of X-ray lines in the afterglow of GRB 011211 has been reported, and challenged. The lines were interpreted as blue-shifted X-rays characteristic of a set of photoionized ``metals'', located in a section of a supernova shell illuminated by a GRB emitted a couple of days after the supernova explosion. We show that the most prominent reported lines coincide with the ones predicted in the ``cannonball'' model of GRBs. In this model, the putative signatures are Hydrogen lines, boosted by the (highly relativistic) motion of the cannonballs (CBs). The corresponding Doppler boost can be extracted from the fit to the observed I-, R- and V-band light-curves of the optical afterglow of GRB 011211, so that, since the redshift is also known, the line energies are --in the CB model-- absolute predictions. We also discuss other GRBs of known redshift which show spectral features generally interpreted as Fe lines, or Fe recombination edges. The ensemble of results is very encouraging from the CB-model's poin...

SPECTROSCOPIC EVIDENCE FOR SN 2010ma ASSOCIATED WITH GRB 101219B

International Nuclear Information System (INIS)

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

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 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 (E iso = 4.2 x 10 51 erg), a bright afterglow, and obeys the 'Amati' relation, thus being fully consistent with the cosmological population of GRBs.

CGRO/BATSE Data Support the New Paradigm For GRB Prompt Emission and the New L-i(nTh)-E-peak,i(nTh,rest) Relation

Science.gov (United States)

Guiriec, S.; Gonzalez, M.M.; Sacahui, J.R.; Kouveliotou, C.; Gehrels, N.; McEnery, J.

2016-01-01

The paradigm for gamma-ray burst (GRB) prompt emission is changing. Since early in the Compton Gamma RayObservatory (CGRO) era, the empirical Band function has been considered a good description of the keV-MeV-gamma-ray prompt emission spectra despite the fact that its shape was very often inconsistent with the theoretical predictions, especially those expected in pure synchrotron emission scenarios. We have recently established a new observational model analyzing data of the NASA Fermi Gamma-ray Space Telescope. In this model, GRB prompt emission would be a combination of three main emission components: (i) a thermal-like component that we have interpreted so far as emission from the jet photosphere, (ii) a non-thermal component that we have interpreted so far as either synchrotron radiation from the propagating and accelerated charged particles within the jet or reprocessed jet photospheric emission, and (iii) an additional non-thermal (cutoff) power law (PL) extending from low to high energies in gamma-rays and most likely of inverse Compton origin. In this article we reanalyze some of the bright GRBs, namely GRBs 941017, 970111, and 990123, observed with the Burst And Transient Source Experiment (BATSE) on board CGRO with the new model. We conclude that BATSE data for these three GRBs are fully consistent with the recent results obtained with Fermi: some bright BATSE GRBs exhibit three separate components during the prompt phase with similar spectral parameters as those reported from Fermi data. In addition, the analysis of the BATSE GRBs with the new prompt emission model results in a relation between the time-resolved energy flux of the non-thermal component, F(in)(Th), and its corresponding nuFnu spectral peak energy,Epeak,inTh (i.e., FinThEpeak,inTh ), which has a similar index when fitted to a PL as the one initially derived from Fermi data. For GRBs with known redshifts (z) this results in a possible universal relation between the luminosity of the non

A Spatially Resolved Study of the GRB 020903 Host Galaxy

Science.gov (United States)

Thorp, Mallory D.; Levesque, Emily M.

2018-03-01

GRB 020903 is a long-duration gamma-ray burst with a host galaxy close enough and extended enough for spatially resolved observations, making it one of less than a dozen GRBs where such host studies are possible. GRB 020903 lies in a galaxy host complex that appears to consist of four interacting components. Here we present the results of spatially resolved spectroscopic observations of the GRB 020903 host. By taking observations at two different position angles, we were able to obtain optical spectra (3600–9000 Å) of multiple regions in the galaxy. We confirm redshifts for three regions of the host galaxy that match that of GRB 020903. We measure the metallicity of these regions, and find that the explosion site and the nearby star-forming regions both have comparable subsolar metallicities. We conclude that, in agreement with past spatially resolved studies of GRBs, the GRB explosion site is representative of the host galaxy as a whole rather than localized in a metal-poor region of the galaxy.

Revealing Physical Activity of GRB Central Engine with Macronova/Kilonova Data

Energy Technology Data Exchange (ETDEWEB)

Shen, Zhao-Qiang; Jin, Zhi-Ping; Liang, Yun-Feng; Li, Xiang; Fan, Yi-Zhong; Wei, Da-Ming, E-mail: yzfan@pmo.ac.cn, E-mail: dmwei@pmo.ac.cn [Key Laboratory of dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Science, Nanjing 210008 (China)

2017-02-01

The modeling of Li-Paczyński macronova/kilonova signals gives a reasonable estimate on the neutron-rich material ejected during the neutron star mergers. Usually the accretion disk is more massive than the macronova ejecta, with which the efficiencies of converting the disk mass into prompt emission of three merger-driven GRBs can hence be directly constrained. Supposing the macronovae/kilonovae associated with GRB 050709, GRB 060614, and GRB 130603B arose from radioactive decay of the r -process material, the upper limit on energy conversion efficiencies are found to be as low as ∼10{sup −6}–10{sup −4}. Moreover, for all three events, neutrino annihilation is likely powerful enough to account for the brief gamma-ray flashes. Neutrino annihilation can also explain the “extended” emission lasting ∼100 s in GRB 050709, but does not work for the one in GRB 060614. These progresses demonstrate that the macronova can serve as a novel probe of the central engine activity.

VLT/X-shooter GRBs: Individual extinction curves of star-forming regions★

Science.gov (United States)

Zafar, T.; Watson, D.; Møller, P.; Selsing, J.; Fynbo, J. PU; Schady, P.; Wiersema, K.; Levan, A. J.; Heintz, K. E.; Postigo, A. de Ugarte; D'Elia, V.; Jakobsson, P.; Bolmer, J.; Japelj, J.; Covino, S.; Gomboc, A.; Cano, Z.

2018-05-01

The extinction profiles in Gamma-Ray Burst (GRB) afterglow spectral energy distributions (SEDs) are usually described by the Small Magellanic Cloud (SMC)-type extinction curve. In different empirical extinction laws, the total-to-selective extinction, RV, is an important quantity because of its relation to dust grain sizes and compositions. We here analyse a sample of 17 GRBs (0.34a single or broken power-law together with a parametric extinction law is used to model the individual SEDs. We find 10 cases with significant dust, where the derived extinction, AV, ranges from 0.1-1.0 mag. In four of those, the inferred extinction curves are consistent with the SMC curve. The GRB individual extinction curves have a flat RV distribution with an optimal weighted combined value of RV = 2.61 ± 0.08 (for seven broad coverage cases). The `average GRB extinction curve' is similar to, but slightly steeper than the typical SMC, and consistent with the SMC Bar extinction curve at ˜95% confidence level. The resultant steeper extinction curves imply populations of small grains, where large dust grains may be destroyed due to GRB activity. Another possibility could be that young age and/or lower metallicities of GRBs environments are responsible for the steeper curves.

SUB-PHOTOSPHERIC EMISSION FROM RELATIVISTIC RADIATION MEDIATED SHOCKS IN GRBs

International Nuclear Information System (INIS)

Bromberg, Omer; Mikolitzky, Ziv; Levinson, Amir

2011-01-01

It is proposed that the prompt emission observed in bursts that exhibit a thermal component originates from relativistic radiation mediated shocks (RRMS) that form below the photosphere of the gamma-ray burst (GRB) outflow. It is argued that such shocks are expected to form in luminous bursts via collisions of shells that propagate with moderate Lorentz factors Γ ∼< 500. Faster shells will collide above the photosphere to form collisionless shocks. We demonstrate that in events like GRB 090902B a substantial fraction of the explosion energy is dissipated below the photosphere, in a region of moderate optical depth τ ∼< 300, whereas in GRB 080916C the major fraction of the energy dissipates above the photosphere. We show that under conditions anticipated in many GRBs, such RRMS convect enough radiation upstream to render photon production in the shock transition negligible, unlike the case of shock breakout in supernovae. The resulting spectrum, as measured in the shock frame, has a relatively low thermal peak, followed by a broad, nonthermal component extending up to the Klein-Nishina limit.

Spectral properties of GRBs observed with BeppoSAX

International Nuclear Information System (INIS)

Costa, E.; Frontera, F.

2003-01-01

The BeppoSAX mission has not only significantly improved the Gamma-Ray Burst science through the discovery of the afterglows but is also providing important data on the prompt events. The Gamma-Ray Burst Monitor is building a catalogue of GRBs that, due to a recently achieved, coarse but suitable positioning capabilities, can usefully integrate and extend the BATSE catalogues. We show the good relative calibration of the two experiments. Wide Field Cameras are providing a sample of about 40 GRBs, in an important band so far relatively ill covered. Moreover the combined use of the two instruments is providing a unique information on the spectral evolution of the GRBs. We show some recent spectral results based on these data and discuss the impact on our knowledge of GRB physics

Fall-Back Disks in Long and Short GRBS

Science.gov (United States)

Cannizo, John K.; Troja, E.; Gehrels, N.

2011-01-01

We present numerical time-dependent calculations for fall-back disks relevant for GRBs in which the disk of material surrounding the black hole (BH) powering the GRB jet modulates the mass flow, and hence the strength of the jet. Given the initial existence of a small mass appr oximately less than 10(exp -4) M(solar) near the progenitor with a circularization radius approximately 10(exp 10) - 10(exp 11) cm, an una voidable consequence will be the formation of an "external disk" whose outer edge continually moves to larger radii due to angular momentum transport and lack of a confining torque. For long GRBs, if the mass distribution in the initial fall-back disk traces the progenitor envelope, then a radius approximates 10(exp 11) cm gives a time scale app roximately 10(exp 4) s for the X-ray plateau. For late times t > 10(exp 7) s a steepening due to a cooling front in the disk may have obser vational support in GRB 060729. For short GRBs, one expects most of t he mass initially to lie at small radii < 10(exp 8) cm; however the presence of even a trace amount approximately 10(exp -9) M(solar) of hi gh angular material can give a brief plateau in the light curve.

Characterizing high-energy light curves of Fermi/Lat GRBs

Energy Technology Data Exchange (ETDEWEB)

Gillette, Jarred [SLAC National Accelerator Lab., Menlo Park, CA (United States)

2015-08-21

A systematic analysis of the light curves of Gamma-Ray Burst (GRBs) with redshift and detected at high-energy (> 100 MeV) by Fermi/LAT has never been done before our work, because there were only a handful of detections. Now we have 20 of those, which we can use to characterize the GRBs in their rest frame. We compared a characteristic decay times Tc of GRBs with redshifts using the new “Pass 8” data, and used a Crystal Ball function to parametrize GRB characteristics. An unexpected anti-correlation between Tc and the peak flux was observed. This means that brighter peaked GRBs have shorter durations. There is also no correlation between the Tc and the decay index, which makes the anti-correlation with brightness more clear. This results appears to be consistent with the External Shock model, which is one of the competing hypothesis on the origin of the high-energy emission. We did not observe any bimodality, which is seen in GRBs at lower energies.

Spitzer Observations of GRB Hosts: A Legacy Approach

Science.gov (United States)

Perley, Daniel; Tanvir, Nial; Hjorth, Jens; Berger, Edo; Laskar, Tanmoy; Michalowski, Michal; Chary, Ranga-Ram; Fynbo, Johan; Levan, Andrew

2012-09-01

The host galaxies of long-duration GRBs are drawn from uniquely broad range of luminosities and redshifts. Thus they offer the possibility of studying the evolution of star-forming galaxies without the limitations of other luminosity-selected samples, which typically are increasingly biased towards the most massive systems at higher redshift. However, reaping the full benefits of this potential requires careful attention to the selection biases affecting host identification. To this end, we propose observations of a Legacy sample of 70 GRB host galaxies (an additional 70 have already been observed by Spitzer), in order to constrain the mass and luminosity function in GRB-selected galaxies at high redshift, including its dependence on redshift and on properties of the afterglow. Crucially, and unlike previous Spitzer surveys, this sample is carefully designed to be uniform and free of optical selection biases that have caused previous surveys to systematically under-represent the role of luminous, massive hosts. We also propose to extend to larger, more powerfully constraining samples the study of two science areas where Spitzer observations have recently shown spectacular success: the hosts of dust-obscured GRBs (which promise to further our understanding of the connection between GRBs and star-formation in the most luminous galaxies), and the evolution of the mass-metallicity relation at z>2 (for which GRB host observations provide particularly powerful constraints on high-z chemical evolution).

Colors and absolute magnitudes of the optical afterglow of GRB060218

Czech Academy of Sciences Publication Activity Database

Šimon, Vojtěch; Pizzichini, G.; Hudec, René

2006-01-01

Roč. 121, č. 12 (2006), s. 1585-1587 ISSN 1594-9982. [Swift and GRBs: Unveiling the Relativistic Universe. Venezia, 05.06.2006-09.06.2006] R&D Projects: GA AV ČR IAA3003206 Grant - others:EU(XE) ESA-PECS project No. 98023; EU(XE) ESA PRODEX INTEGRAL 90108 Institutional research plan: CEZ:AV0Z10030501 Source of funding: V - iné verejné zdroje ; V - iné verejné zdroje Keywords : gamma-ray bursts * radiation mechanisms * supernovae Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.351, year: 2006

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).

The luminosity function and formation rate history of GRBs

International Nuclear Information System (INIS)

Firmani, C.; Avila-Reese, V.; Ghisellini, G.; Tutukov, A.V.

2005-01-01

The isotropic luminosity function (LF) and formation rate history (FRH) of long GRBs is by the first time constrained by using jointly both the observed GRB peak-flux and redshift distributions. Our results support an evolving LF and a FRH that keeps increasing after z = 2. We discuss some interesting implications related to these results

Search for high-energy neutrinos from bright GRBs with ANTARES

NARCIS (Netherlands)

Albert, A.; André, M.; Anghinolfi, M.; Anton, G.; Ardid, M.; Aubert, J.-J.; Avgitas, T.; Baret, B.; Barrios-Martí, J.; Basa, S.; Bertin, V.; Biagi, S.; Bormuth, R.; Bourret, S.; Bouwhuis, M.C.; Bruijn, R.; Brunner, J.; Busto, J.; Capone, A.; Caramete, L.; Carr, J.; Celli, S.; Chiarusi, T.; Circella, M.; Coelho, J.A.B.; Coleiro, A.; Coniglione, R.; Costantini, H.; Coyle, P.; Creusot, A.; Deschamps, A.; De Bonis, G.; Distefano, C.; Di Palma, I.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; El Bojaddaini, I.; Elsässer, D.; Enzenhöfer, A.; Felis, I.; Fusco, L.A.; Galatà, S.; Gay, P.; Geißelsöder, S.; Geyer, K.; Giordano, V.; Gleixner, A.; Glotin, H.; Grégoire, T.; Gracia-Ruiz, R.; Graf, K.; Hallmann, S.; van Haren, H.; Heijboer, A.J.; Hello, Y.; Hernández-Rey, J.J.; Hößl, J.; Hofestädt, J.; Hugon, C.; Illuminati, G.; James, C.W.; de Jong, M.; Jongen, M.; Kadler, M.; Kalekin, O.; Katz, U.; Kießling, D.; Kouchner, A.; Kreter, M.; Kreykenbohm, I.; Kulikovskiy, V.; Lachaud, C.; Lahmann, R.; Lefèvre, D.; Leonora, E.; Lotze, M.; Loucatos, S.; Marcelin, M.; Margiotta, A.; Marinelli, A.; Martínez-Mora, J.A.; Mathieu, A.; Mele, R.; Melis, K.; Michael, T.; Migliozzi, P.; Moussa, A.; Mueller, C.; Nezri, E.; Pavalas, G.E.; Pellegrino, C.; Perrina, C.; Piattelli, P.; Popa, V.; Pradier, T.; Quinn, L.; Racca, C.; Riccobene, G.; Roensch, K.; Sánchez-Losa, A.; Saldaña, M.; Salvadori, I.; Samtleben, D.F.E.; Sanguineti, M.; Sapienza, P.; Schnabel, J.; Schüssler, F.; Seitz, T.; Sieger, C.; Spurio, M.; Stolarczyk, T.; Taiuti, M.; Tayalati, Y.; Trovato, A.; Tselengidou, M.; Turpin, D.; Tönnis, C.; Vallage, B.; Vallée, C.; Van Elewyck, V.; Vivolo, D.; Vizzocca, A.; Wagner, S.; Wilms, J.; Zornoza, J.D.; Zúñiga, J.

2017-01-01

Gamma-ray bursts are thought to be sites of hadronic acceleration, thus neutrinos are expected from the decay of charged particles, produced in pγ interactions. The methods and results of a search for muon neutrinos in the data of the ANTARES neutrino telescope from four bright GRBs (GRB 080916C,

DISCOVERY OF THE BROAD-LINED TYPE Ic SN 2013cq ASSOCIATED WITH THE VERY ENERGETIC GRB 130427A

Energy Technology Data Exchange (ETDEWEB)

Xu, D.; Krühler, T.; Hjorth, J.; Malesani, D.; Fynbo, J. P. U.; Watson, D. J.; Geier, S. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 København Ø (Denmark); De Ugarte Postigo, A.; Thöne, C. C.; Sánchez-Ramírez, R. [Instituto de Astrofísica de Andalucía, CSIC, Glorieta de la Astronomía s/n, E-18008 Granada (Spain); Leloudas, G. [The Oskar Klein Centre, Department of Physics, Stockholm University, AlbaNova, SE-10691 Stockholm (Sweden); Cano, Z.; Jakobsson, P. [Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Dunhagi 5, IS-107 Reykjavik (Iceland); Schulze, S. [Departamento de Astronomía y Astrofísica, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22 (Chile); Kaper, L. [Astronomical Institute Anton Pannekoek, University of Amsterdam, Science Park 904, NL-1098 XH Amsterdam (Netherlands); Sollerman, J. [The Oskar Klein Centre, Department of Astronomy, Stockholm University, AlbaNova, SE-10691 Stockholm (Sweden); Cabrera-Lavers, A. [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain); Cao, C. [Department of Space Science and Physics, Shandong University at Weihai, Weihai, Shandong 264209 (China); Covino, S. [INAF/Brera Astronomical Observatory, via Bianchi 46, I-23807 Merate (Italy); Flores, H., E-mail: dong@dark-cosmology.dk [Laboratoire Galaxies Etoiles Physique et Instrumentation, Observatoire de Paris, 5 place Jules Janssen, F-92195 Meudon (France); and others

2013-10-20

Long-duration gamma-ray bursts (GRBs) at z < 1 are found in most cases to be accompanied by bright, broad-lined Type Ic supernovae (SNe Ic-BL). The highest-energy GRBs are mostly located at higher redshifts, where the associated SNe are hard to detect observationally. Here, we present early and late observations of the optical counterpart of the very energetic GRB 130427A. Despite its moderate redshift, z = 0.3399 ± 0.0002, GRB 130427A is at the high end of the GRB energy distribution, with an isotropic-equivalent energy release of E{sub iso} ∼ 9.6 × 10{sup 53} erg, more than an order of magnitude more energetic than other GRBs with spectroscopically confirmed SNe. In our dense photometric monitoring, we detect excess flux in the host-subtracted r-band light curve, consistent with that expected from an emerging SN, ∼0.2 mag fainter than the prototypical SN 1998bw. A spectrum obtained around the time of the SN peak (16.7 days after the GRB) reveals broad undulations typical of SNe Ic-BL, confirming the presence of an SN, designated SN 2013cq. The spectral shape and early peak time are similar to those of the high expansion velocity SN 2010bh associated with GRB 100316D. Our findings demonstrate that high-energy, long-duration GRBs, commonly detected at high redshift, can also be associated with SNe Ic-BL, pointing to a common progenitor mechanism.

LFsGRB: Binary neutron star merger rate via the luminosity function of short gamma-ray bursts

Science.gov (United States)

Paul, Debdutta

2018-04-01

LFsGRB models the luminosity function (LF) of short Gamma Ray Bursts (sGRBs) by using the available catalog data of all short GRBs (sGRBs) detected till 2017 October, estimating the luminosities via pseudo-redshifts obtained from the Yonetoku correlation, and then assuming a standard delay distribution between the cosmic star formation rate and the production rate of their progenitors. The data are fit well both by exponential cutoff powerlaw and broken powerlaw models. Using the derived parameters of these models along with conservative values in the jet opening angles seen from afterglow observations, the true rate of short GRBs is derived. Assuming a short GRB is produced from each binary neutron star merger (BNSM), the rate of gravitational wave (GW) detections from these mergers are derived for the past, present and future configurations of the GW detector networks.

Batse/Sax and Batse/RXTE-ASM Joint Spectral Studies of GRBs

Science.gov (United States)

Paciesas, William S.

2002-01-01

We proposed to make joint spectral analysis of gamma-ray bursts (GRBs) in the BATSE data base that are located within the fields of view of either the BeppoSAX wide field cameras (WFCs) or the RXTE all-sky monitor (ASM). The very broad-band coverage obtained in this way would facilitate various studies of GRB spectra that are difficult to perform with BATSE data alone. Unfortunately, the termination of the CGRO mission in June 2000 was not anticipated at the time of the proposal, and the sample of common events turned out to be smaller than we would have liked.

Constraining the Type of Central Engine of GRBs with Swift Data

Science.gov (United States)

Li, Liang; Wu, Xue-Feng; Lei, Wei-Hua; Dai, Zi-Gao; Lian, En-Wei; Ryde, Felix

2018-06-01

The central engine of gamma-ray bursts (GRBs) is poorly constrained. There exist two main candidates: a fast-rotating black hole and a rapidly spinning magnetar. Furthermore, X-ray plateaus are widely accepted to be the energy injection into the external shock. In this paper, we systematically analyze the Swift/XRT light curves of 101 GRBs having plateau phases and known redshifts (before 2017 May). Since a maximum energy budget (∼2 × 1052 erg) exists for magnetars but not for black holes, this provides a good clue to identifying the type of GRB central engine. We calculate the isotropic kinetic energy E K,iso and the isotropic X-ray energy release E X,iso for individual GRBs. We identify three categories based on how likely a black hole harbors a central engine: “Gold” (9 out of 101; both E X,iso and E K,iso exceed the energy budget), “Silver” (69 out of 101; E X,iso less than the limit but E K,iso greater than the limit), and “Bronze” (23 out of 101; the energies are not above the limit). We then derive and test the black hole parameters with the Blandford–Znajek mechanism, and find that the observations of the black hole candidate (“Gold” + “Silver”) samples are consistent with the expectations of the black hole model. Furthermore, we also test the magnetar candidate (“Bronze”) sample with the magnetar model, and find that the magnetar surface magnetic field (B p ) and initial spin period (P 0) fall into reasonable ranges. Our analysis indicates that if the magnetar wind is isotropic, a magnetar central engine is possible for 20% of the analyzed GRBs. For most GRBs, a black hole is most likely operating.

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

International Nuclear Information System (INIS)

Ackermann, M.; Ajello, M.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Borgland, A. W.; Bouvier, A.; Baldini, L.; Bellazzini, R.; Bregeon, J.; Brez, A.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; Bhat, P. N.; Briggs, M. S.; Bissaldi, E.; Bonamente, E.; Brigida, M.

2010-01-01

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.

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.;

ASTROSAT CZT IMAGER OBSERVATIONS OF GRB 151006A: TIMING, SPECTROSCOPY, AND POLARIZATION STUDY

Energy Technology Data Exchange (ETDEWEB)

Rao, A. R.; Chand, Vikas; Hingar, M. K.; Iyyani, S.; Khanna, Rakesh; Kutty, A. P. K.; Malkar, J. P.; Paul, D. [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai (India); Bhalerao, V. B.; Bhattacharya, D.; Dewangan, G. C.; Pawar, Pramod; Vibhute, A. M. [Inter University Center for Astronomy and Astrophysics, Pune (India); Chattopadhyay, T.; Mithun, N. P. S.; Vadawale, S. V.; Vagshette, N. [Physical Research Laboratory, Ahmedabad (India); Basak, R. [Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, Warsaw (Poland); Pradeep, P.; Samuel, Essy, E-mail: arrao@tifr.res.in [Vikram Sarabhai Space Centre, Thiruvananthapuram (India); and others

2016-12-10

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 the CZT Imager can localize this GRB correctly to about a few degrees, and it can provide, in conjunction with Swift , spectral parameters similar to those obtained from Fermi /GBM. Hence, the 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 localization 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: the CZT Imager is able to identify Compton scattered events thereby providing polarization information for bright GRBs. GRB 151006A, in spite of being relatively faint, shows hints of a polarization signal at 100–300 keV (though at a low significance level). We point out that the CZT Imager should provide significant time resolved polarization measurements for GRBs that have fluence three times higher than that of GRB 151006A. We estimate that the number of such bright GRBs detectable by the CZT Imager is five to six per year. The CZT Imager can also act as a good hard X-ray monitoring device for possible electromagnetic counterparts of gravitational wave events.

The Structure and Dynamics of GRB Jets

Energy Technology Data Exchange (ETDEWEB)

Granot, Jonathan; /KIPAC, Menlo Park

2006-10-25

There are several lines of evidence which suggest that the relativistic outflows in gamma-ray bursts (GRBs) are collimated into narrow jets. The jet structure has important implications for the true energy release and the event rate of GRBs, and can constrain the mechanism responsible for the acceleration and collimation of the jet. Nevertheless, the jet structure and its dynamics as it sweeps up the external medium and decelerates, are not well understood. In this review I discuss our current understanding of GRB jets, stressing their structure and dynamics.

A PHOTOMETRIC REDSHIFT OF z ∼ 9.4 FOR GRB 090429B

International Nuclear Information System (INIS)

Cucchiara, A.; Fox, D. B.; Wu, X. F.; Toma, K.; Levan, A. J.; Tanvir, N. R.; Rowlinson, A.; Ukwatta, T. N.; Berger, E.; Kruehler, T.; Greiner, J.; Olivares, F. E.; Yoldas, A. Kuepcue; Amati, L.; Sakamoto, T.; Roth, K.; Stephens, A.; Fritz, Alexander; Fynbo, J. P. U.; Hjorth, J.

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 ∼ 9.4 for the Swift detected GRB 090429B based on deep observations with Gemini-North, the Very Large Telescope, and the GRB Optical and Near-infrared Detector. Assuming a Small Magellanic Cloud dust law (which has been found in a majority of GRB sight lines), the 90% likelihood range for the redshift is 9.06 7. The non-detection of the host galaxy to deep limits (Y(AB) ∼ 28, which would correspond roughly to 0.001L* at z = 1) in our late-time optical and infrared observations with the Hubble Space Telescope strongly supports the extreme-redshift origin of GRB 090429B, since we would expect to have detected any low-z galaxy, even if it were highly dusty. Finally, the energetics of GRB 090429B are comparable to those of other GRBs and suggest that its progenitor is not greatly different from those of lower redshift bursts.

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

DEFF Research Database (Denmark)

D'Elia, V.; Fynbo, Johan Peter Uldall; Goldoni, P.

2014-01-01

we used to derive information on the distance between the host absorbing gas and the site of the GRB explosion. The variability of the FeI\\lambda2396 excited line between the two epochs proves that these features are excited by the GRB UV flux. Moreover, the distance of component I is found to be d......I=200+100-60 pc, while component II is located closer to the GRB, at dII=100+40-30 pc. These values are among the lowest found in GRBs. Component III does not show excited transitions, so it should be located farther away from the GRB. The presence of H2 molecules is firmly established, with a molecular...

THE ELECTROMAGNETIC MODEL OF SHORT GRBs, THE NATURE OF PROMPT TAILS, SUPERNOVA-LESS LONG GRBs, AND HIGHLY EFFICIENT EPISODIC ACCRETION

Energy Technology Data Exchange (ETDEWEB)

Lyutikov, Maxim [Department of Physics, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907-2036 (United States)

2013-05-01

Many short gamma-ray bursts (GRBs) show prompt tails lasting up to hundreds of seconds that can be energetically dominant over the initial sub-second spike. In this paper we develop an electromagnetic model of short GRBs that explains the two stages of the energy release, the prompt spike and the prompt tail. The key ingredient of the model is the recent discovery that an isolated black hole can keep its open magnetic flux for times much longer than the collapse time and thus can spin down electromagnetically, driving the relativistic wind. First, the merger is preceded by an electromagnetic precursor wind with total power L{sub p} Almost-Equal-To (((GM{sub NS}){sup 3}B{sub NS}{sup 2})/c{sup 5}R){proportional_to}(-t){sup - Vulgar-Fraction-One-Quarter }, reaching 3 Multiplication-Sign 10{sup 44} erg s{sup -1} for typical neutron star masses of 1.4 M{sub Sun} and magnetic fields B {approx} 10{sup 12} G. If a fraction of this power is converted into pulsar-like coherent radio emission, this may produce an observable radio burst of a few milliseconds (like the Lorimer burst). At the active stage of the merger, two neutron stars produce a black hole surrounded by an accretion torus in which the magnetic field is amplified to {approx}10{sup 15} G. This magnetic field extracts the rotational energy of the black hole and drives an axially collimated electromagnetic wind that may carry of the order of 10{sup 50} erg, limited by the accretion time of the torus, a few hundred milliseconds. For observers nearly aligned with the orbital normal this is seen as a classical short GRB. After the accretion of the torus, the isolated black hole keeps the open magnetic flux and drives the equatorially (not axially) collimated outflow, which is seen by an observer at intermediate polar angles as a prompt tail. The tail carries more energy than the prompt spike, but its emission is de-boosted for observers along the orbital normal. Observers in the equatorial plane miss the prompt spike

The redshift and afterglow of the extremely energetic gamma-ray burst GRB 080916C

CERN Document Server

Greiner, J.; Kruehler, T.; Kienlin, A.v.; Rau, A.; Sari, R.; Fox, Derek B.; Kawai, N.; Afonso, P.; Ajello, M.; Berger, E.; Cenko, S.B.; Cucchiara, A.; Filgas, R.; Klose, S.; Yoldas, A.Kuepue; Lichti, G.G.; Loew, S.; McBreen, S.; Nagayama, T.; Rossi, A.; Sato, S.; Szokoly, G.; Yoldas, A.; Zhang, X.-L.

2009-01-01

The detection of GeV photons from gamma-ray bursts (GRBs) has important consequences for the interpretation and modelling of these most-energetic cosmological explosions. The full exploitation of the high-energy measurements relies, however, on the accurate knowledge of the distance to the events. Here we report on the discovery of the afterglow and subsequent redshift determination of GRB 080916C, the first GRB detected by the Fermi Gamma-Ray Space Telescope with high significance detection of photons at >0.1 GeV. Observations were done with 7-channel imager GROND at the 2.2m MPI/ESO telescope, the SIRIUS instrument at the Nagoya-SAAO 1.4m telescope in South Africa, and the GMOS instrument at Gemini-S. The afterglow photometric redshift of z=4.35+-0.15, based on simultaneous 7-filter observations with the Gamma-Ray Optical and Near-infrared Detector (GROND), places GRB 080916C among the top 5% most distant GRBs, and makes it the most energetic GRB known to date. The detection of GeV photons from such a dista...

Fermi observations of high-energy gamma-ray emission from GRB 080916C.

Science.gov (United States)

Abdo, A A; Ackermann, M; Arimoto, M; Asano, K; Atwood, W B; Axelsson, M; Baldini, L; Ballet, J; Band, D L; Barbiellini, G; Baring, M G; Bastieri, D; Battelino, M; Baughman, B M; Bechtol, K; Bellardi, F; Bellazzini, R; Berenji, B; Bhat, P N; Bissaldi, E; Blandford, R D; Bloom, E 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, T H; Burrows, D; Busetto, G; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Ceccanti, M; Cecchi, C; Celotti, A; Charles, E; Chekhtman, A; Cheung, C C; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; Cominsky, L R; Connaughton, V; Conrad, J; Costamante, L; Cutini, S; Deklotz, M; Dermer, C D; de Angelis, A; de Palma, F; Digel, S W; Dingus, B L; do Couto E Silva, E; Drell, P S; Dubois, R; Dumora, D; Edmonds, Y; Evans, P A; Fabiani, D; Farnier, C; Favuzzi, C; Finke, J; 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, T; Godfrey, G; Goldstein, A; Granot, J; Greiner, J; Grenier, I A; Grondin, M-H; Grove, J E; Guillemot, L; Guiriec, S; Haller, G; Hanabata, Y; Harding, A K; Hayashida, M; Hays, E; Hernando Morat, J A; Hoover, A; Hughes, R E; Jóhannesson, G; Johnson, A S; Johnson, R P; Johnson, T J; Johnson, W N; Kamae, T; Katagiri, H; Kataoka, J; Kavelaars, A; Kawai, N; Kelly, H; Kennea, J; Kerr, M; Kippen, R M; Knödlseder, J; Kocevski, D; Kocian, M L; Komin, N; Kouveliotou, C; Kuehn, F; Kuss, M; 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, P; Madejski, G M; Makeev, A; Marangelli, B; Mazziotta, M N; McBreen, S; McEnery, J E; McGlynn, S; Meegan, C; Mészáros, 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, I V; Murgia, S; Nakamori, T; Nelson, D; Nolan, P L; Norris, J P; Nuss, E; Ohno, M; Ohsugi, T; Okumura, A; 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, V; Pinchera, M; Piron, F; Porter, T A; Preece, R; Rainò, S; Ramirez-Ruiz, E; Rando, R; Rapposelli, E; Razzano, M; Razzaque, S; Rea, N; Reimer, A; Reimer, O; Reposeur, T; Reyes, L C; Ritz, S; Rochester, L S; Rodriguez, A Y; Roth, M; Ryde, F; Sadrozinski, H F-W; Sanchez, D; Sander, A; Saz Parkinson, P M; Scargle, J D; Schalk, T L; Segal, K N; Sgrò, C; Shimokawabe, T; Siskind, E J; Smith, D A; Smith, P D; Spandre, G; Spinelli, P; Stamatikos, M; Starck, J-L; Stecker, F W; Steinle, H; Stephens, T E; Strickman, M S; Suson, D J; Tagliaferri, G; Tajima, H; Takahashi, H; Takahashi, T; Tanaka, T; Tenze, A; Thayer, J B; Thayer, J G; Thompson, D J; Tibaldo, L; Torres, D 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

2009-03-27

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.

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.

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

International Nuclear Information System (INIS)

Virgili, F. J.; Mundell, C. G.; Harrison, R.; Kobayashi, S.; Steele, I. A.; Mottram, C. J.; Clay, N. R.; Pal'shin, V.; Guidorzi, C.; Margutti, R.; Chornock, R.; Melandri, A.; Henden, A.; Updike, A. C.; Cenko, S. B.; Tanvir, N. R.; Cucchiara, A.; Gomboc, A.; Levan, A.; Cano, Z.

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 (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 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.

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, A.; 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.; Yamaoka, K.

2012-12-01

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 γ < 3 × 1049 erg), soft spectrum, and unusual spectral lag connect this GRB to the class of sub-energetic 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.

BROADBAND STUDY OF GRB 091127: A SUB-ENERGETIC BURST AT HIGHER REDSHIFT?

Energy Technology Data Exchange (ETDEWEB)

Troja, E.; Sakamoto, T.; Brown, J. C.; Gehrels, N.; Marshall, F. E.; Racusin, J. L. [NASA, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Guidorzi, C. [Physics Department, University of Ferrara, via Saragat 1, I-44122, Ferrara (Italy); Norris, J. P. [Physics Department, Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Panaitescu, A. [Space Science and Applications, MS D466, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Kobayashi, S.; Mawson, N.; Melandri, A.; Mundell, C. G.; Steele, I. A. [Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, CH41 1LD Birkenhead (United Kingdom); Omodei, N. [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); Burrows, D. N. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Evans, P. A. [X-ray and Observational Astronomy Group, Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Oates, S. R. [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom); Pal' shin, V. [Ioffe Physico-Technical Institute, Laboratory for Experimental Astrophysics, 26 Polytekhnicheskaya, St Petersburg 194021 (Russian Federation); Preece, R. D. [Department of Physics, University of Alabama in Huntsville, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States); and others

2012-12-10

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}} < 3 Multiplication-Sign 10{sup 49} erg), soft spectrum, and unusual spectral lag connect this GRB to the class of sub-energetic 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.

Jets in Hydrogen-poor Superluminous Supernovae: Constraints from a Comprehensive Analysis of Radio Observations

Science.gov (United States)

Coppejans, D. L.; Margutti, R.; Guidorzi, C.; Chomiuk, L.; Alexander, K. D.; Berger, E.; Bietenholz, M. F.; Blanchard, P. K.; Challis, P.; Chornock, R.; Drout, M.; Fong, W.; MacFadyen, A.; Migliori, G.; Milisavljevic, D.; Nicholl, M.; Parrent, J. T.; Terreran, G.; Zauderer, B. A.

2018-03-01

The energy source powering the extreme optical luminosity of hydrogen-stripped superluminous supernovae (SLSNe-I) is not known, but recent studies have highlighted the case for a central engine. Radio and/or X-ray observations are best placed to track the fastest ejecta and probe the presence of outflows from a central engine. We compile all the published radio observations of SLSNe-I to date and present three new observations of two new SLSNe-I. None were detected. Through modeling the radio emission, we constrain the subparsec environments and possible outflows in SLSNe-I. In this sample, we rule out on-axis collimated relativistic jets of the kind detected in gamma-ray bursts (GRBs). We constrain off-axis jets with opening angles of 5° (30°) to energies of {E}{{k}}values {ε }e=0.1 and {ε }B=0.01. The deepest limits rule out emission of the kind seen in faint uncollimated GRBs (with the exception of GRB 060218) and from relativistic SNe. Finally, for the closest SLSN-I, SN 2017egm, we constrain the energy of an uncollimated nonrelativistic outflow like those observed in normal SNe to {E}{{k}}≲ {10}48 erg.

ESTIMATING LONG GRB JET OPENING ANGLES AND REST-FRAME ENERGETICS

Energy Technology Data Exchange (ETDEWEB)

Goldstein, Adam [Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Connaughton, Valerie [Science and Technology Institute, Universities Space Research Association, Huntsville, AL 35805 (United States); Briggs, Michael S.; Burns, Eric, E-mail: adam.m.goldstein@nasa.gov [Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35899 (United States)

2016-02-10

We present a method to estimate the jet opening angles of long duration gamma-ray bursts (GRBs) using the prompt gamma-ray energetics and an inversion of the Ghirlanda relation, which is a correlation between the time-integrated peak energy of the GRB prompt spectrum and the collimation-corrected energy in gamma-rays. The derived jet opening angles using this method and detailed assumptions match well with the corresponding inferred jet opening angles obtained when a break in the afterglow is observed. Furthermore, using a model of the predicted long GRB redshift probability distribution observable by the Fermi Gamma-ray Burst Monitor (GBM), we estimate the probability distributions for the jet opening angle and rest-frame energetics for a large sample of GBM GRBs for which the redshifts have not been observed. Previous studies have only used a handful of GRBs to estimate these properties due to the paucity of observed afterglow jet breaks, spectroscopic redshifts, and comprehensive prompt gamma-ray observations, and we potentially expand the number of GRBs that can be used in this analysis by more than an order of magnitude. In this analysis, we also present an inferred distribution of jet breaks which indicates that a large fraction of jet breaks are not observable with current instrumentation and observing strategies. We present simple parameterizations for the jet angle, energetics, and jet break distributions so that they may be used in future studies.

The VLT/X-shooter GRB afterglow legacy survey

Science.gov (United States)

Kaper, Lex; Fynbo, Johan P. U.; Pugliese, Vanna; van Rest, Daan

2017-11-01

The Swift satellite allows us to use gamma-ray bursts (GRBs) to peer through the hearts of star forming galaxies through cosmic time. Our open collaboration, representing most of the active European researchers in this field, builds a public legacy sample of GRB X-shooter spectroscopy while Swift continues to fly. To date, our spectroscopy of more than 100 GRB afterglows covers a redshift range from 0.059 to about 8 (Tanvir et al. 2009, Nature 461, 1254), with more than 20 robust afterglow-based metallicity measurements (over a redshift range from 1.7 to 5.9). With afterglow spectroscopy (throughout the electromagnetic spectrum from X-rays to the sub-mm) we can hence characterize the properties of star-forming galaxies over cosmic history in terms of redshift, metallicity, molecular content, ISM temperature, UV-flux density, etc.. These observations provide key information on the final evolution of the most massive stars collapsing into black holes, with the potential of probing the epoch of the formation of the first (very massive) stars. VLT/X-shooter (Vernet et al. 2011, A&A 536, A105) is in many ways the ideal GRB follow-up instrument and indeed GRB follow-up was one of the primary science cases behind the instrument design and implementation. Due to the wide wavelength coverage of X-shooter, in the same observation one can detect molecular H2 absorption near the atmospheric cut-off and many strong emission lines from the host galaxy in the near-infrared (e.g., Friis et al. 2015, MNRAS 451, 167). For example, we have measured a metallicity of 0.1 Z ⊙ for GRB 100219A at z = 4.67 (Thöne et al. 2013, MNRAS 428, 3590), 0.02 Z ⊙ for GRB 111008A at z = 4.99 (Sparre et al. 2014, ApJ 785, 150) and 0.05 Z ⊙ for GRB 130606A at z = 5.91 (Hartoog et al. 2015, A&A 580, 139). In the latter, the very high value of [Al/Fe]=2.40 +/- 0.78 might be due to a proton capture process and may be a signature of a previous generation of massive (perhaps even the first) stars

Wide-Field Gamma-Spectrometer BDRG: GRB Monitor On-Board the Lomonosov Mission

Science.gov (United States)

Svertilov, S. I.; Panasyuk, M. I.; Bogomolov, V. V.; Amelushkin, A. M.; Barinova, V. O.; Galkin, V. I.; Iyudin, A. F.; Kuznetsova, E. A.; Prokhorov, A. V.; Petrov, V. L.; Rozhkov, G. V.; Yashin, I. V.; Gorbovskoy, E. S.; Lipunov, V. M.; Park, I. H.; Jeong, S.; Kim, M. B.

2018-02-01

The study of GRB prompt emissions (PE) is one of the main goals of the Lomonosov space mission. The payloads of the GRB monitor (BDRG) with the wide-field optical cameras (SHOK) and the ultra-fast flash observatory (UFFO) onboard the Lomonosov satellite are intended for the observation of GRBs, and in particular, their prompt emissions. The BDRG gamma-ray spectrometer is designed to obtain the temporal and spectral information of GRBs in the energy range of 10-3000 keV as well as to provide GRB triggers on several time scales (10 ms, 1 s and 20 s) for ground and space telescopes, including the UFFO and SHOK. The BDRG instrument consists of three identical detector boxes with axes shifted by 90° from each other. This configuration allows us to localize a GRB source in the sky with an accuracy of ˜ 2°. Each BDRG box contains a phoswich NaI(Tl)/CsI(Tl) scintillator detector. A thick CsI(Tl) crystal in size of \\varnothing 130 × 17 mm is placed underneath the NaI(Tl) as an active shield in the soft energy range and as the main detector in the hard energy range. The ratio of the CsI(Tl) to NaI(Tl) event rates at varying energies can be employed as an independent metric to distinguish legitimate GRB signals from false positives originating from electrons in near-Earth vicinities. The data from three detectors are collected in a BA BDRG information unit, which generates a GRB trigger and a set of data frames in output format. The scientific data output is ˜ 500 Mb per day, including ˜ 180 Mb of continuous data for events with durations in excess of 100 ms for 16 channels in each detector, detailed energy spectra, and sets of frames with ˜ 5 Mb of detailed information for each burst-like event. A number of pre-flight tests including those for the trigger algorithm and calibration were carried out to confirm the reliability of the BDRG for operation in space.

Early danish GRB experiments - And some for the future?

DEFF Research Database (Denmark)

Lund, Niels

2013-01-01

by a japanese report of a balloon instrument for GRB studies based on a Rotation Modulation Collimator we at the Danish Space Research Institute started the development of an RMC detector for GRBs, the WATCH wide field monitor. Four WATCH units were flown on the Soviet Granat satellites, and one on ESA's EURECA...

Black Hole Universe Model for Explaining GRBs, X-Ray Flares, and Quasars as Emissions of Dynamic Star-like, Massive, and Supermassive Black Holes

Science.gov (United States)

Zhang, Tianxi

2014-01-01

Slightly modifying the standard big bang theory, the author has recently developed a new cosmological model called black hole universe, which is consistent with Mach’s principle, governed by Einstein’s general theory of relativity, and able to explain all observations of the universe. Previous studies accounted for the origin, structure, evolution, expansion, cosmic microwave background radiation, and acceleration of the 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 the emissions of dynamic black holes according to the black hole universe model and provides a self-consistent explanation for the observations of gamma ray bursts (GRBs), X-ray flares, and quasars as emissions of dynamic star-like, massive, and supermassive black holes. It is shown that a black hole, when it accretes its ambient matter or merges with other black holes, becomes dynamic. Since the event horizon of a dynamic black hole is broken, the inside hot (or high-frequency) blackbody radiation leaks out. The leakage of the inside hot blackbody radiation leads to a GRB if it is a star-like black hole, an X-ray flare if it is a massive black hole like the one at the center of the Milky Way, or a quasar if it is a supermassive black hole like an active galactic nucleus (AGN). The energy spectra and amount of emissions produced by the dynamic star-like, massive, and supermassive black holes can be consistent with the measurements of GRBs, X-ray flares, and quasars.

LOBSTER EYE: New approach to monitor GRBs in X-rays

International Nuclear Information System (INIS)

Hudec, R.; Hudcova, V.; Inneman, A.; Pina, L.

2003-01-01

The detection of X-ray afterglows for the large majority of GRBs allows a novel X-ray experiment to be considered to monitor and to detect GRBs based on their X-ray emission. Such an experiment could provide not only a superior localization accuracy if compared with gamma ray instruments, but probably also a higher rate based on the theoretical assumption that the beaming in gamma rays is narrower if compared with lower energies. We describe and discuss the LOBSTER EYE X-ray telescope project including results of the development and tests of the telescope prototype. Considerations for a space experiment on a small scientific satellite of a Nadezhda type are also presented and discussed. The scientific aspects of such experiment regarding the GRB study and statistics are addressed

BOOTES-IR: near IR follow-up GRB observations by a robotic system

International Nuclear Information System (INIS)

Castro-Tirado, A.J.; Postrigo, A. de Ugarte; Jelinek, M.

2005-01-01

BOOTES-IR is the extension of the BOOTES experiment, which operates in Southern Spain since 1998, to the near IR (NIR). The goal is to follow up the early stage of the gamma ray burst (GRB) afterglow emission in the NIR, alike BOOTES does already at optical wavelengths. The scientific case that drives the BOOTES-IR performance is the study of GRBs with the support of spacecraft like INTEGRAL, SWIFT and GLAST. Given that the afterglow emission in both, the NIR and the optical, in the instances immediately following a GRB, is extremely bright (reached V = 8.9 in one case), it should be possible to detect this prompt emission at NIR wavelengths too. The combined observations by BOOTES-IR and BOOTES-1 and BOOTES-2 will allow for real time identification of trustworthy candidates to have a high redshift (z > 5). It is expected that, few minutes after a GRB, the IR magnitudes be H ∼ 7-10, hence very high quality spectra can be obtained for objects as far as z = 10 by larger instruments

Selection effects on GRB spectral-energy correlations

International Nuclear Information System (INIS)

Nava, Lara; Ghirlanda, Giancarlo; Ghisellini, Gabriele

2009-01-01

Instrumental selection effects can act upon the estimates of the peak energy E peak obs , the fluence F and the peak flux P of GRBs. If this were the case, then the correlations involving the corresponding rest frame quantities (i.e. E peak , E obs and the peak luminosity L iso ) would be questioned. We estimated, as a function of E peak obs , the minimum peak flux necessary to trigger a GRB and the minimum fluence a burst must have to determine the value of E peak obs by considering different instruments (BATSE, Swift, BeppoSAX). We find that the latter dominates over the former. We then study the E peak obs -fluence (and flux) correlation in the observer plane. GRBs with redshift show well defined E peak obs -F and E peak obs -P correlations: in this planes the selection effects are present, but do not determine the found correlations. This is not true for Swift GRBs with redshift, for which the spectral analysis threshold does affect their distribution in the observer planes. Extending the sample to GRBs without z, we still find a significant E peak obs -F correlation, although with a larger scatter than that defined by GRBs with redshift. We find that 6% are outliers of the Amati correlation. The E peak obs -P correlation of GRBs with or without redshift is the same and no outlier is found among bursts without redshift.

An Ordinary Short Gamma-Ray Burst with Extraordinary Implications: Fermi -GBM Detection of GRB 170817A

Energy Technology Data Exchange (ETDEWEB)

Goldstein, A.; Roberts, O. J.; Connaughton, V. [Science and Technology Institute, Universities Space Research Association, Huntsville, AL 35805 (United States); Veres, P.; Briggs, M. S.; Hamburg, R.; Preece, R. D.; Poolakkil, S. [Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35899 (United States); Burns, E.; Racusin, J.; Canton, T. Dal [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kocevski, D.; Wilson-Hodge, C. A.; Hui, C. M.; Littenberg, T. [Astrophysics Office, ST12, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Kienlin, A. von [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany); Christensen, N.; Broida, J. [Physics and Astronomy, Carleton College, MN 55057 (United States); Siellez, K. [Center for Relativistic Astrophysics and School of Physics, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Blackburn, L., E-mail: Adam.M.Goldstein@nasa.gov [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); and others

2017-10-20

On 2017 August 17 at 12:41:06 UTC the Fermi Gamma-ray Burst Monitor (GBM) detected and triggered on the short gamma-ray burst (GRB) 170817A. Approximately 1.7 s prior to this GRB, the Laser Interferometer Gravitational-wave Observatory triggered on a binary compact merger candidate associated with the GRB. This is the first unambiguous coincident observation of gravitational waves and electromagnetic radiation from a single astrophysical source and marks the start of gravitational-wave multi-messenger astronomy. We report the GBM observations and analysis of this ordinary short GRB, which extraordinarily confirms that at least some short GRBs are produced by binary compact mergers.

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

A tale of two GRB-SNe at a common redshift of ζ = 0.54

International Nuclear Information System (INIS)

Cano, Z.; Bersier, D.; Kobayashi, S.; Clay, N.; Mottram, C.; Mundell, C.G.; Small, E.; Smith, R.J.; Steele, I.; Guidorzi, C.; Curran, P.A.

2011-01-01

We present ground-based and Hubble Space Telescope 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 broad-band 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 times. In the context of a simple jet-like model, the afterglow of GRB 090618 is best explained by the presence of a jet-break at t - t 0 ≥ 0.5 d. We then compare the rest-frame, peak V-band absolute magnitudes of all of the GRB and X-Ray Flash (XRF)-associated SNe with a large sample of local Type Ibc SNe, concluding that, when host extinction is considered, the peak magnitudes of the GRB/XRF-SNe cannot be distinguished from the peak magnitudes of non-GRB/XRF SNe. (authors)

A Reverse Shock and Unusual Radio Properties in GRB 160625B

Science.gov (United States)

Alexander, K. D.; Laskar, T.; Berger, E.; Guidorzi, C.; Dichiara, S.; Fong, W.; Gomboc, A.; Kobayashi, S.; Kopac, D.; Mundell, C. G.; Tanvir, N. R.; Williams, P. K. G.

2017-10-01

We present multi-wavelength observations and modeling of the exceptionally bright long γ-ray burst GRB 160625B. The optical and X-ray data are well fit by synchrotron emission from a collimated blastwave with an opening angle of {θ }j≈ 3\\buildrel{\\circ}\\over{.} 6 and kinetic energy of {E}K≈ 2× {10}51 erg, propagating into a low-density (n≈ 5× {10}-5 cm-3) medium with a uniform profile. The forward shock is sub-dominant in the radio band; instead, the radio emission is dominated by two additional components. The first component is consistent with emission from a reverse shock, indicating an initial Lorentz factor of {{{Γ }}}0≳ 100 and an ejecta magnetization of {R}B≈ 1{--}100. The second component exhibits peculiar spectral and temporal evolution and is most likely the result of scattering of the radio emission by the turbulent Milky Way interstellar medium (ISM). Such scattering is expected in any sufficiently compact extragalactic source and has been seen in GRBs before, but the large amplitude and long duration of the variability seen here are qualitatively more similar to extreme scattering events previously observed in quasars, rather than normal interstellar scintillation effects. High-cadence, broadband radio observations of future GRBs are needed to fully characterize such effects, which can sensitively probe the properties of the ISM and must be taken into account before variability intrinsic to the GRB can be interpreted correctly.

A low-latency pipeline for GRB light curve and spectrum using Fermi/GBM near real-time data

Science.gov (United States)

Zhao, Yi; Zhang, Bin-Bin; Xiong, Shao-Lin; Long, Xi; Zhang, Qiang; Song, Li-Ming; Sun, Jian-Chao; Wang, Yuan-Hao; Li, Han-Cheng; Bu, Qing-Cui; Feng, Min-Zi; Li, Zheng-Heng; Wen, Xing; Wu, Bo-Bing; Zhang, Lai-Yu; Zhang, Yong-Jie; Zhang, Shuang-Nan; Shao, Jian-Xiong

2018-05-01

Rapid response and short time latency are very important for Time Domain Astronomy, such as the observations of Gamma-ray Bursts (GRBs) and electromagnetic (EM) counterparts of gravitational waves (GWs). Based on near real-time Fermi/GBM data, we developed a low-latency pipeline to automatically calculate the temporal and spectral properties of GRBs. With this pipeline, some important parameters can be obtained, such as T 90 and fluence, within ∼ 20 min after the GRB trigger. For ∼ 90% of GRBs, T 90 and fluence are consistent with the GBM catalog results within 2σ errors. This pipeline has been used by the Gamma-ray Bursts Polarimeter (POLAR) and the Insight Hard X-ray Modulation Telescope (Insight-HXMT) to follow up the bursts of interest. For GRB 170817A, the first EM counterpart of GW events detected by Fermi/GBM and INTEGRAL/SPI-ACS, the pipeline gave T 90 and spectral information 21 min after the GBM trigger, providing important information for POLAR and Insight-HXMT observations.

Prompt gamma-ray emission of GRB 170817A associated to GW 170817: A consistent picture

Science.gov (United States)

Ziaeepour, Houri

2018-05-01

The short GRB 170817A associated to the first detection of gravitation waves from a Binary Neutron Star (BNS) merger was in many ways unusual. Possible explanations are emission from a cocoon or cocoon break out, off-axis view of a structured or uniform jet, and on-axis ultra-relativistic jet with reduced density and Lorentz factor. Here we use a phenomenological model of shock evolution and synchrotron/self-Compton emission to simulate the prompt emission of GRB 170817A and to test above proposals. We find that synchrotron emission from a mildly relativistic cocoon with a Lorentz factor of 2-3, as considered in the literature, generates a too soft, too long, and too bright prompt emission. Off-axis view of an structured jet with a Lorentz factor of about 10 can reproduce observations, but needs a very efficient transfer of kinetic energy to electrons in internal shocks, which is disfavored by particle in cell simulations. We also comment on cocoon breakout as a mechanism for generation of the prompt gamma-ray. A relativistic jet with a Lorentz factor of about 100 and a density lower than typical short GRBs seems to be the most plausible model and we conclude that GRB 170817A was intrinsically faint. Based on this result and findings of relativistic magnetohydrodynamics simulations of BNS merger in the literature we discuss physical and astronomical conditions, which may lead to such faint short GRBs. We identify small mass difference of progenitor neutron stars, their old age and reduced magnetic field, and anti-alignment of spin-orbit angular momentum induced by environmental gravitational disturbances during the lifetime of the BNS as causes for the faintness of GRB 170817A. We predict that BNS mergers at lower redshifts generate on average fainter GRBs.

Enhanced cosmological GRB rates and implications for cosmogenic neutrinos

International Nuclear Information System (INIS)

Yueksel, Hasan; Kistler, Matthew D.

2007-01-01

Gamma-ray bursts, which are among the most violent events in the Universe, are one of the few viable candidates to produce ultra high-energy cosmic rays. Recently, observations have revealed that GRBs generally originate from metal-poor, low-luminosity galaxies and do not directly trace cosmic star formation, as might have been assumed from their association with core-collapse supernovae. Several implications follow from these findings. The redshift distribution of observed GRBs is expected to peak at higher redshift (compared to cosmic star formation), which is supported by the mean redshift of the Swift GRB sample, ∼3. If GRBs are, in fact, the source of the observed UHECR, then cosmic-ray production would evolve with redshift in a stronger fashion than has been previously suggested. This necessarily leads, through the GZK process, to an enhancement in the flux of cosmogenic neutrinos, providing a near-term approach for testing the gamma-ray burst-cosmic-ray connection with ongoing and proposed UHE neutrino experiments

The ultraluminous GRB 110918A

International Nuclear Information System (INIS)

Frederiks, D. D.; Svinkin, D. S.; Pal'shin, V. D.; Aptekar, R. L.; Golenetskii, S. V.; Mazets, E. P.; Oleynik, Ph. P.; Tsvetkova, A. E.; Ulanov, M. V.; Kokomov, A. A.; Hurley, K.; Mangano, V.; Burrows, D. N.; Sbarufatti, B.; Siegel, M. H.; Oates, S.; Cline, T. L.; Krimm, H. A.; Pagani, C.; Mitrofanov, I. G.

2013-01-01

GRB 110918A is the brightest long gamma-ray burst (GRB) detected by Konus-WIND during its almost 19 yr of continuous observations and the most luminous GRB ever observed since the beginning of the cosmological era in 1997. We report on the final Interplanetary Network 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 moderate peak energy 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 ± 0.1) × 10 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 ± 0.2) × 10 54 erg s –1 . A tail of the soft γ-ray emission was detected with temporal and spectral behavior typical of that predicted by the synchrotron forward-shock model. The Swift/X-Ray Telescope and the Swift/Ultraviolet Optical Telescope observed the bright afterglow from 1.2 to 48 days after the burst and revealed no evidence of a jet break. The post-break scenario for the afterglow is preferred from our analysis, with a hard underlying electron spectrum and interstellar-medium-like circumburst environment implied. We conclude that, among the multiple reasons investigated, the tight collimation of the jet must have been a key ingredient to produce this unusually bright burst. The inferred jet opening angle of 1.°7-3.°4 results in reasonable values of the collimation-corrected radiated energy and the peak luminosity, which, however, are still at the top of their distributions for such tightly collimated events. We estimate a detection horizon for a similar ultraluminous GRB of z ∼ 7.5 for Konus-WIND and z ∼ 12 for the Swift/Burst Alert Telescope, which stresses the importance of GRBs as probes of the early Universe.

A binary neutron star GRB model

International Nuclear Information System (INIS)

Wilson, J.R.; Salmonson, J.D.; Wilson, J.R.; Mathews, G.J.

1998-01-01

In this paper we present the preliminary results of a model for the production of gamma-ray bursts (GRBs) through the compressional heating of binary neutron stars near their last stable orbit prior to merger. Recent numerical studies of the general relativistic (GR) hydrodynamics in three spatial dimensions of close neutron star binaries (NSBs) have uncovered evidence for the compression and heating of the individual neutron stars (NSs) prior to merger 12. This effect will have significant effect on the production of gravitational waves, neutrinos and, ultimately, energetic photons. The study of the production of these photons in close NSBs and, in particular, its correspondence to observed GRBs is the subject of this paper. The gamma-rays arise as follows. Compressional heating causes the neutron stars to emit neutrino pairs which, in turn, annihilate to produce a hot electron-positron pair plasma. This pair-photon plasma expands rapidly until it becomes optically thin, at which point the photons are released. We show that this process can indeed satisfy three basic requirements of a model for cosmological gamma-ray bursts: (1) sufficient gamma-ray energy release (>10 51 ergs) to produce observed fluxes, (2) a time-scale of the primary burst duration consistent with that of a 'classical' GRB (∼10 seconds), and (3) the peak of the photon number spectrum matches that of 'classical' GRB (∼300 keV). copyright 1998 American Institute of Physics

GRB 110731A within the IGC paradigm

Directory of Open Access Journals (Sweden)

Primorac Daria

2018-01-01

Full Text Available Bright gamma-ray burst (GRB 110731A was simultaneously observed by Fermi and Swift observatories, with a follow up optical observation which inferred the redshift of z = 2.83. Thus, available data are spanning from optical to high energy (GeV emission. We analyze these data within the induced gravitational collapse (IGC paradigm, recently introduced to explain temporal coincidence of some long GRBs with type Ic supernovae. The case of binary-driven hypcrnova (BdHN assumes a close system, which starts as an evolved core - neutron star binary. After the core-collapse event, the new NS - black hole system is formed, emitting the GRB in the process. We performed the time-resolved and time-integrated analysis of the Fermi data. Preliminary results gave isotropic energy Eiso = 6.05 × 1053 erg and the total P-GRB energy of Ep–GRB = 3.7 × 1052 erg. At transparency point we found a Lorentz factor Γ ~ 2.17 × 103 laboratory radius of 8.33 x 1013 cm, P-GRB observed temperature of 168 keV and a baryon load B = 4.35 × 10-4. Simulated light-curve and prompt emission spectra showed the average circum burst medium density to be n ~ 0.03 particles per cm3. We reproduced the X-ray light-curve within the rest-frame of the source, finding the common late power-law behavior, with α = –1.22. Considering these results, we interpret GRB 110731A as a member of a BdHNe group.

GRB 110731A within the IGC paradigm

Science.gov (United States)

Primorac, Daria; Ruffini, Remo; Pisani, Giovanni Battista; Aimuratov, Yerlan; Biancol, Carlo Luciano; Karlica, Mile; Melon Fuksman, Julio David; Moradi, Rahim; Muccino, Marco; Penacchioni, Ana Virginia; Rueda, Jorge Armando; Wang, Yu

2018-01-01

Bright gamma-ray burst (GRB) 110731A was simultaneously observed by Fermi and Swift observatories, with a follow up optical observation which inferred the redshift of z = 2.83. Thus, available data are spanning from optical to high energy (GeV) emission. We analyze these data within the induced gravitational collapse (IGC) paradigm, recently introduced to explain temporal coincidence of some long GRBs with type Ic supernovae. The case of binary-driven hypcrnova (BdHN) assumes a close system, which starts as an evolved core - neutron star binary. After the core-collapse event, the new NS - black hole system is formed, emitting the GRB in the process. We performed the time-resolved and time-integrated analysis of the Fermi data. Preliminary results gave isotropic energy Eiso = 6.05 × 1053 erg and the total P-GRB energy of Ep-GRB = 3.7 × 1052 erg. At transparency point we found a Lorentz factor Γ 2.17 × 103 laboratory radius of 8.33 x 1013 cm, P-GRB observed temperature of 168 keV and a baryon load B = 4.35 × 10-4. Simulated light-curve and prompt emission spectra showed the average circum burst medium density to be n 0.03 particles per cm3. We reproduced the X-ray light-curve within the rest-frame of the source, finding the common late power-law behavior, with α = -1.22. Considering these results, we interpret GRB 110731A as a member of a BdHNe group.

A New Era of Submillimeter GRB Afterglow Follow-Ups with the Greenland Telescope

Science.gov (United States)

Urata, Yuji; Huang, Kuiyun; Asada, Keiichi; Hirashita, Hiroyuki; Inoue, Makoto; Ho, Paul T. P.

A planned rapid submillimeter (submm) Gamma Ray Burst (GRBs) follow-up observations conducted using the Greenland Telescope (GLT) is presented. The GLT is a 12-m submm telescope to be located at the top of the Greenland ice sheet, where the high-altitude and dry weather porvides excellent conditions for observations at submm wavelengths. With its combination of wavelength window and rapid responding system, the GLT will explore new insights on GRBs. Summarizing the current achievements of submm GRB follow-ups, we identify the following three scientific goals regarding GRBs: (1) systematic detection of bright submm emissions originating from reverse shock (RS) in the early afterglow phase, (2) characterization of forward shock and RS emissions by capturing their peak flux and frequencies and performing continuous monitoring, and (3) detections of GRBs as a result of the explosion of first-generation stars result of GRBs at a high redshift through systematic rapid follow ups. The light curves and spectra calculated by available theoretical models clearly show that the GLT could play a crucial role in these studies.

VizieR Online Data Catalog: GRB prompt emission fitted with the DREAM model (Ahlgren+, 2015)

Science.gov (United States)

Ahlgren, B.; Larsson, J.; Nymark, T.; Ryde, F.; Pe'Er, A.

2018-01-01

We illustrate the application of the DREAM model by fitting it to two different, bright Fermi GRBs; GRB 090618 and GRB 100724B. While GRB 090618 is well fitted by a Band function, GRB 100724B was the first example of a burst with a significant additional BB component (Guiriec et al. 2011ApJ...727L..33G). GRB 090618 is analysed using Gamma-ray Burst Monitor (GBM) data (Meegan et al. 2009ApJ...702..791M) from the NaI and BGO detectors. For GRB 100724B, we used GBM data from the NaI and BGO detectors as well as Large Area Telescope Low Energy (LAT-LLE) data. For both bursts we selected NaI detectors seeing the GRB at an off-axis angle lower than 60° and the BGO detector as being the best aligned of the two BGO detectors. The spectra were fitted in the energy ranges 8-1000 keV (NaI), 200-40000 keV (BGO) and 30-1000 MeV (LAT-LLE). (2 data files).

Prompt and Afterglow Emission Properties of Gamma-Ray Bursts with Spectroscopically Identified Supernovae

Energy Technology Data Exchange (ETDEWEB)

Kaneko, Yuki; Ramirez-Ruiz, E.; Granot, J.; Kouveliotou, C.; Woosley, S.E.; Patel, S.K.; Rol, E.; Zand, J.J.M.in' t; a; Wijers, R.A.M.J.; Strom, R.; /USRA, Huntsville

2006-07-12

We present a detailed spectral analysis of the prompt and afterglow emission of four nearby long-soft gamma-ray bursts (GRBs 980425, 030329, 031203, and 060218) that were spectroscopically found to be associated with type Ic supernovae, and compare them to the general GRB population. For each event, we investigate the spectral and luminosity evolution, and estimate the total energy budget based upon broadband observations. The observational inventory for these events has become rich enough to allow estimates of their energy content in relativistic and sub-relativistic form. The result is a global portrait of the effects of the physical processes responsible for producing long-soft GRBs. In particular, we find that the values of the energy released in mildly relativistic outflows appears to have a significantly smaller scatter than those found in highly relativistic ejecta. This is consistent with a picture in which the energy released inside the progenitor star is roughly standard, while the fraction of that energy that ends up in highly relativistic ejecta outside the star can vary dramatically between different events.

An optical study of the GRB 970111 field beginning 19 hours after the gamma-ray burst

DEFF Research Database (Denmark)

Gorosabel, J.; Castro-Tirado, A.J.; Wolf, Christian

1998-01-01

to estimate photometric redshifts in the range 0.2 4 for several galaxies in this field and we did not find any conspicuous unusual object. We note that GRB 970111 and GRB 980329 could belong to the same class of GRBs, which may be related to nearby sources (2 similar to 1) in which high intrinsic...... with B galaxy with redshift z = 0.657, which we propose as the optical counterpart of the X-ray source. Further observations allowed to perform...... multicolour photometry for objects in the GRB 970111 error box. The colour-colour diagrams do not show any object with unusual colours. We applied a photometric classification method to the objects inside the GRB error box, that can distinguish stars from galaxies and estimate redshifts. We were able...

A tale of two GRB-SNe at a common redshift of z=0.54

NARCIS (Netherlands)

Cano, Z.; Bersier, D.; 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.; de Ugarte Postigo, A.; 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.

2011-01-01

We present ground-based and Hubble Space Telescope 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 broad-band spectral

Constraints on the optical afterglow emission of the short/hard burst GRB 010119

DEFF Research Database (Denmark)

Gorosabel, J.; Andersen, M.I.; Hjorth, J.

2002-01-01

We report optical observations of the short/hard burst GRB 010119 error box, one of the smallest error boxes reported to date for short/hard GRBs. Limits of R >22.3 and I >21.2 are imposed by observations carried out 20.31 and 20.58 hours after the gamma-ray event, respectively. They represent th...

On the Origin of the Mass-Metallicity Relation for GRB Host Galaxies

Energy Technology Data Exchange (ETDEWEB)

Kocevski, Daniel; /KIPAC, Menlo Park; West, Andrew A.; /Boston U., Dept. Astron.

2011-06-02

We investigate the nature of the mass-metallicity (M-Z) relation for long gamma-ray burst (LGRB) host galaxies. Recent studies suggest that the M-Z relation for local LGRB host galaxies may be systematically offset towards lower metallicities relative to the M-Z relation defined by the general star forming galaxy (SDSS) population. The nature of this offset is consistent with suggestions that low metallicity environments may be required to produce high mass progenitors, although the detection of several GRBs in high-mass, high-metallicity galaxies challenges the notion of a strict metallicity cut-off for host galaxies that are capable of producing GRBs. We show that the nature of this reported offset may be explained by a recently proposed anti-correlation between the star formation rate (SFR) and the metallicity of star forming galaxies. If low metallicity galaxies produce more stars than their equally massive, high-metallicity counterparts, then transient events that closely trace the SFR in a galaxy would be more likely to be found in these low metallicity, low mass galaxies. Therefore, the offset between the GRB and SDSS defined M-Z relations may be the result of the different methods used to select their respective galaxy populations, with GRBs being biased towards low metallicity, high SFR, galaxies. We predict that such an offset should not be expected of transient events that do not closely follow the star formation history of their host galaxies, such as short duration GRBs and SN Ia, but should be evident in core collapse SNe found through upcoming untargeted surveys.

HIGH-ENERGY EMISSION OF GRB 130427A: EVIDENCE FOR INVERSE COMPTON RADIATION

International Nuclear Information System (INIS)

Fan, Yi-Zhong; Zhang, Fu-Wen; He, Hao-Ning; Zhou, Bei; Yang, Rui-Zhi; Jin, Zhi-Ping; Wei, Da-Ming; Tam, P. H. T.; Liang, Yun-Feng

2013-01-01

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 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

Four Years of Real-Time GRB Followup by BOOTES-1B (2005–2008

Directory of Open Access Journals (Sweden)

Martin Jelínek

2010-01-01

Full Text Available Four years of BOOTES-1B GRB follow-up history are summarised for the first time in the form of a table. The successfully followed events are described case by case. Further, the data are used to show the GRB trigger rate in Spain on a per-year basis, resulting in an estimate of 18 triggers and about 51 hours of telescope time per year for real-time triggers. These numbers grow to about 22 triggers and 77 hours per year if we include also the GRBs observable within 2 hours after the trigger.

On the physical processes which lie at the bases of time variability of GRBs

International Nuclear Information System (INIS)

Ruffini, R.; Bianco, C. L.; Fraschetti, F.; Xue, S-S.

2001-01-01

The relative-space-time-transformation (RSTT) paradigm and the interpretation of the burst-structure (IBS) paradigm are applied to probe the origin of the time variability of GRBs. Again GRB 991216 is used as a prototypical case, thanks to the precise data from the CGRO, RXTE and Chandra satellites. It is found that with the exception of the relatively inconspicuous but scientifically very important signal originating from the initial proper gamma ray burst (P-GRB), all the other spikes and time variabilities can be explained by the interaction of the accelerated-baryonic-matter pulse with inhomogeneities in the interstellar matter. This can be demonstrated by using the RSTT paradigm as well as the IBS paradigm, to trace a typical spike observed in arrival time back to the corresponding one in the laboratory time. Using these paradigms, the identification of the physical nature of the time variability of the GRBs can be made most convincingly. It is made explicit the dependence of a) the intensities of the afterglow, b) the spikes amplitude and c) the actual time structure on the Lorentz gamma factor of the accelerated-baryonic-matter pulse. In principle it is possible to read off from the spike structure the detailed density contrast of the interstellar medium in the host galaxy, even at very high redshift

A New Era of Submillimeter GRB Afterglow Follow-Ups with the Greenland Telescope

Directory of Open Access Journals (Sweden)

Yuji Urata

2015-01-01

Full Text Available Planned rapid submillimeter (submm gamma-ray-bursts (GRBs follow-up observations conducted using the Greenland Telescope (GLT are presented. The GLT is a 12-m submm telescope to be located at the top of the Greenland ice sheet, where the high altitude and dry weather porvide excellent conditions for observations at submm wavelengths. With its combination of wavelength window and rapid responding system, the GLT will explore new insights on GRBs. Summarizing the current achievements of submm GRB follow-ups, we identify the following three scientific goals regarding GRBs: (1 systematic detection of bright submm emissions originating from reverse shock (RS in the early afterglow phase, (2 characterization of forward shock and RS emissions by capturing their peak flux and frequencies and performing continuous monitoring, and (3 detections of GRBs at a high redshift as a result of the explosion of first generation stars through systematic rapid follow-ups. The light curves and spectra calculated by available theoretical models clearly show that the GLT could play a crucial role in these studies.

The afterglow and elliptical host galaxy of the short gamma-ray burst GRB 050724.

Science.gov (United States)

Berger, E; Price, P A; 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

2005-12-15

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 coalescence of binary compact objects (neutron stars or black holes), the progenitors, energetics and environments of these events remain elusive despite recent localizations. Here we report the discovery of the first radio afterglow from the short burst GRB 050724, which unambiguously associates it with an elliptical galaxy at a redshift z = 0.257. We show that the burst is powered by the same relativistic fireball mechanism as long GRBs, with the ejecta possibly collimated in jets, but that the total energy release is 10-1,000 times smaller. More importantly, the nature of the host galaxy demonstrates that short GRBs arise from an old (> 1 Gyr) stellar population, strengthening earlier suggestions and providing support for coalescing compact object binaries as the progenitors.

Possible GRB Observation with the MAGIC Telescope

Science.gov (United States)

Bastieri, D.; Bigongiari, C.; Mariotti, M.; Peruzzo, L.; Saggion, A.

2001-08-01

The MAGIC Telescope, with its reflecting parabolic dish of 17 m of diameter and its careful design of a robust, lightweight, alto-azimuthal mount, is an ideal detector for GRB phenomena. The telescope is an air Cherenkov telescope that, even in the first phase, equipped with standard PMTs, can reach an energy threshold below 30 GeV. The threshold is going to drop well below 10 GeV in the envisaged second phase, when chamber PMTs will be substituted by high quantum efficiency APDs. The telescope can promptly respond to GRB alerts coming, for instance, from GCN, and can reposition itself in less than 30 seconds, 20 seconds being the time to turn half a round for the azimuth bearing. In this report, the effective area of the detector as a function of energy and zenith angle is taken into account, in order to evaluate the expected yearly occurrence and the response to different kinds of GRBs.

GRB 090227B: THE MISSING LINK BETWEEN THE GENUINE SHORT AND LONG GAMMA-RAY BURSTS

Energy Technology Data Exchange (ETDEWEB)

Muccino, M.; Ruffini, R.; Bianco, C. L.; Izzo, L.; Penacchioni, A. V. [Dip. di Fisica and ICRA, Sapienza Universita di Roma, Piazzale Aldo Moro 5, I-00185 Rome (Italy)

2013-02-15

The time-resolved spectral analysis of GRB 090227B, made possible by the Fermi-GBM data, allows us to identify in this source the missing link between the genuine short and long gamma-ray bursts (GRBs). Within the Fireshell model of the GRBs we predict genuine short GRBs: bursts with the same inner engine of the long bursts but endowed with a severely low value of the baryon load, B {approx}< 5 Multiplication-Sign 10{sup -5}. A first energetically predominant emission occurs at the transparency of the e {sup +} e {sup -} plasma, the Proper-GRB (P-GRB), followed by a softer emission, the extended afterglow. The typical separation between the two emissions is expected to be of the order of 10{sup -3}-10{sup -2} s. We identify the P-GRB of GRB 090227B in the first 96 ms of emission, where a thermal component with the temperature kT = (517 {+-} 28) keV and a flux comparable with the non-thermal part of the spectrum is observed. This non-thermal component as well as the subsequent emission, where there is no evidence for a thermal spectrum, is identified with the extended afterglow. We deduce a theoretical cosmological redshift z = 1.61 {+-} 0.14. We then derive the total energy E{sup tot}{sub e{sup +}e{sup -}}= (2.83{+-}0.15) Multiplication-Sign 10{sup 53} erg, the baryon load B = (4.13 {+-} 0.05) Multiplication-Sign 10{sup -5}, the Lorentz {Gamma} factor at transparency {Gamma}{sub tr} = (1.44 {+-} 0.01) Multiplication-Sign 10{sup 4}, and the intrinsic duration {Delta}t' {approx} 0.35 s. We also determine the average density of the circumburst medium (CBM), (n {sub CBM}) = (1.90 {+-} 0.20) Multiplication-Sign 10{sup -5} particles cm{sup -3}. There is no evidence of beaming in the system. In view of the energetics and of the baryon load of the source, as well as of the low interstellar medium and of the intrinsic timescale of the signal, we identify the GRB progenitor as a binary neutron star. From the recent progress in the theory of neutron stars, we obtain

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.

CONNECTING GRBs AND ULIRGs: A SENSITIVE, UNBIASED SURVEY FOR RADIO EMISSION FROM GAMMA-RAY BURST HOST GALAXIES AT 0 < z < 2.5

Energy Technology Data Exchange (ETDEWEB)

Perley, D. A. [Department of Astronomy, California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Perley, R. A. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Hjorth, J.; Malesani, D. [Dark Cosmology Centre, Niels Bohr Institute, DK-2100 Copenhagen (Denmark); Michałowski, M. J. [Scottish Universities Physics Alliance, Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh, EH9 3HJ (United Kingdom); Cenko, S. B. [NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Jakobsson, P. [Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Dunhagi 5, 107 Reykjavík (Iceland); Krühler, T. [European Southern Observatory, Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago 19 (Chile); Levan, A. J. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Tanvir, N. R., E-mail: dperley@astro.caltech.edu [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom)

2015-03-10

Luminous infrared galaxies and submillimeter galaxies contribute significantly to stellar mass assembly and provide an important test of the connection between the gamma-ray burst (GRB) rate and that of overall cosmic star formation. We present sensitive 3 GHz radio observations using the Karl G. Jansky Very Large Array of 32 uniformly selected GRB host galaxies spanning a redshift range from 0 < z < 2.5, providing the first fully dust- and sample-unbiased measurement of the fraction of GRBs originating from the universe's most bolometrically luminous galaxies. Four galaxies are detected, with inferred radio star formation rates (SFRs) ranging between 50 and 300 M {sub ☉} yr{sup –1}. Three of the four detections correspond to events consistent with being optically obscured 'dark' bursts. Our overall detection fraction implies that between 9% and 23% of GRBs between 0.5 < z < 2.5 occur in galaxies with S {sub 3GHz} > 10 μJy, corresponding to SFR > 50 M {sub ☉} yr{sup –1} at z ∼ 1 or >250 M {sub ☉} yr{sup –1} at z ∼ 2. Similar galaxies contribute approximately 10%-30% of all cosmic star formation, so our results are consistent with a GRB rate that is not strongly biased with respect to the total SFR of a galaxy. However, all four radio-detected hosts have stellar masses significantly lower than IR/submillimeter-selected field galaxies of similar luminosities. We suggest that the GRB rate may be suppressed in metal-rich environments but independently enhanced in intense starbursts, producing a strong efficiency dependence on mass but little net dependence on bulk galaxy SFR.

Estimating detection rates for the LIGO-Virgo search for gravitational-wave burst counterparts to gamma-ray bursts using inferred local GRB rates

International Nuclear Information System (INIS)

Leonor, I; Frey, R; Sutton, P J; Jones, G; Marka, S; Marka, Z

2009-01-01

One of the ongoing searches performed using the LIGO-Virgo network of gravitational-wave interferometers is the search for gravitational-wave burst (GWB) counterparts to gamma-ray bursts (GRBs). This type of analysis makes use of GRB time and position information from gamma-ray satellite detectors to trigger the GWB search, and the GWB detection rates possible for such an analysis thus strongly depend on the GRB detection efficiencies of the satellite detectors. Using local GRB rate densities inferred from observations which are found in the science literature, we calculate estimates of the GWB detection rates for different configurations of the LIGO-Virgo network for this type of analysis.

Identifying the Location in the Host Galaxy of Short GRB 1111l7A with the Chandra Sub- Arcsecond Position

Science.gov (United States)

Sakamoto, Takanori; Troja, E.; Aoki, K.; Guiriec, S.; Im, M.; Leloudas, G.; Malesani, D.; Melandri, A.; deUgartePostigo, A.; Urata, Y.;

Automated detection of optical counterparts to GRBs with RAPTOR

International Nuclear Information System (INIS)

Wozniak, P. R.; Vestrand, W. T.; Evans, S.; White, R.; Wren, J.

2006-01-01

The RAPTOR system (RAPid Telescopes for Optical Response) is an array of several distributed robotic telescopes that automatically respond to GCN localization alerts. Raptor-S is a 0.4-m telescope with 24 arc min. field of view employing a 1k x 1k Marconi CCD detector, and has already detected prompt optical emission from several GRBs within the first minute of the explosion. We present a real-time data analysis and alert system for automated identification of optical transients in Raptor-S GRB response data down to the sensitivity limit of ∼ 19 mag. Our custom data processing pipeline is designed to minimize the time required to reliably identify transients and extract actionable information. The system utilizes a networked PostgreSQL database server for catalog access and distributes email alerts with successful detections

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.

ENERGETIC FERMI/LAT GRB 100414A: ENERGETIC AND CORRELATIONS

Energy Technology Data Exchange (ETDEWEB)

Urata, Yuji; Tsai, Patrick P. [Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan (China); Huang, Kuiyun [Academia Sinica Institute of Astronomy and Astrophysics, Taipei 106, Taiwan (China); Yamaoka, Kazutaka [Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1, Fuchinobe, Sayamihara 229-8558 (Japan); Tashiro, Makoto S., E-mail: urata@astro.ncu.edu.tw [Department of Physics, Saitama University, Shimo-Okubo, Saitama 338-8570 (Japan)

2012-03-20

This study presents multi-wavelength observational results for energetic GRB 100414A with GeV photons. The prompt spectral fitting using Suzaku/WAM data yielded spectral peak energies of E{sup src}{sub peak} of 1458.7{sup +132.6}{sub -106.6} keV and E{sub iso} of 34.5{sup +2.0}{sub -1.8} Multiplication-Sign 10{sup 52} erg with z = 1.368. The optical afterglow light curves between 3 and 7 days were effectively fitted according to a simple power law with a temporal index of {alpha} = -2.6 {+-} 0.1. The joint light curve with earlier Swift/UVOT observations yields a temporal break at 2.3 {+-} 0.2 days. This was the first Fermi/LAT detected event that demonstrated the clear temporal break in the optical afterglow. The jet opening angle derived from this temporal break was 5.{sup 0}8, consistent with those of other well-observed long gamma-ray bursts (GRBs). The multi-wavelength analyses in this study showed that GRB 100414A follows E{sup src}{sub peak}-E{sub iso} and E{sup src}{sub peak}-E{sub {gamma}} correlations. The late afterglow revealed a flatter evolution with significant excesses at 27.2 days. The most straightforward explanation for the excess is that GRB 100414A was accompanied by a contemporaneous supernova. The model light curve based on other GRB-SN events is marginally consistent with that of the observed light curve.

ENERGETIC FERMI/LAT GRB 100414A: ENERGETIC AND CORRELATIONS

International Nuclear Information System (INIS)

Urata, Yuji; Tsai, Patrick P.; Huang, Kuiyun; Yamaoka, Kazutaka; Tashiro, Makoto S.

2012-01-01

This study presents multi-wavelength observational results for energetic GRB 100414A with GeV photons. The prompt spectral fitting using Suzaku/WAM data yielded spectral peak energies of E src peak of 1458.7 +132.6 –106.6 keV and E iso of 34.5 +2.0 –1.8 × 10 52 erg with z = 1.368. The optical afterglow light curves between 3 and 7 days were effectively fitted according to a simple power law with a temporal index of α = –2.6 ± 0.1. The joint light curve with earlier Swift/UVOT observations yields a temporal break at 2.3 ± 0.2 days. This was the first Fermi/LAT detected event that demonstrated the clear temporal break in the optical afterglow. The jet opening angle derived from this temporal break was 5. 0 8, consistent with those of other well-observed long gamma-ray bursts (GRBs). The multi-wavelength analyses in this study showed that GRB 100414A follows E src peak -E iso and E src peak -E γ correlations. The late afterglow revealed a flatter evolution with significant excesses at 27.2 days. The most straightforward explanation for the excess is that GRB 100414A was accompanied by a contemporaneous supernova. The model light curve based on other GRB-SN events is marginally consistent with that of the observed light curve.

Time-resolved spectral analysis of prompt emission from long gamma-ray bursts with GeV emission

International Nuclear Information System (INIS)

Rao Arikkala Raghurama; Basak Rupal; Bhattacharya Jishnu; Chandra Sarthak; Maheshwari Nikunj; Choudhury Manojendu; Misra Ranjeev

2014-01-01

We performed detailed time-resolved spectroscopy of bright long gamma-ray bursts (GRBs) which show significant GeV emissions (GRB 080916C, GRB 090902B and GRB 090926A). In addition to the standard Band model, we also use a model consisting of a black body and a power law to fit the spectra. We find that for the latter model there are indications of an additional soft component in the spectra. While previous studies have shown that such models are required for GRB 090902B, here we find that a composite spectral model consisting of two blackbodies and a power law adequately fits the data of all the three bright GRBs. We investigate the evolution of the spectral parameters and find several interesting features that appear in all three GRBs, like (a) temperatures of the blackbodies are strongly correlated with each other, (b) fluxes in the black body components are strongly correlated with each other, (c) the temperatures of the black body trace the profile of the individual pulses of the GRBs, and (d) the characteristics of power law components like the spectral index and the delayed onset bear a close similarity to the emission characteristics in the GeV regions. We discuss the implications of these results and the possibility of identifying the radiation mechanisms during the prompt emission of GRBs. (research papers)

THE OPTICALLY UNBIASED GRB HOST (TOUGH) SURVEY. III. REDSHIFT DISTRIBUTION

Energy Technology Data Exchange (ETDEWEB)

Jakobsson, P.; Chapman, R.; Vreeswijk, P. M. [Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Dunhagi 5, 107 Reykjavik (Iceland); Hjorth, J.; Malesani, D.; Fynbo, J. P. U.; Milvang-Jensen, B. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen (Denmark); Tanvir, N. R.; Starling, R. L. C. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Letawe, G. [Departement d' Astrophysique, Geophysique et Oceanographie, ULg, Allee du 6 aout, 17-Bat. B5c B-4000 Liege (Sart-Tilman) (Belgium)

2012-06-10

We present 10 new gamma-ray burst (GRB) redshifts and another five redshift limits based on host galaxy spectroscopy obtained as part of a large program conducted at the Very Large Telescope (VLT). The redshifts span the range 0.345 {<=} z {approx}< 2.54. Three of our measurements revise incorrect values from the literature. The homogeneous host sample researched here consists of 69 hosts that originally had a redshift completeness of 55% (with 38 out of 69 hosts having redshifts considered secure). Our project, including VLT/X-shooter observations reported elsewhere, increases this fraction to 77% (53/69), making the survey the most comprehensive in terms of redshift completeness of any sample to the full Swift depth, analyzed to date. We present the cumulative redshift distribution and derive a conservative, yet small, associated uncertainty. We constrain the fraction of Swift GRBs at high redshift to a maximum of 14% (5%) for z > 6 (z > 7). The mean redshift of the host sample is assessed to be (z) {approx}> 2.2, with the 10 new redshifts reducing it significantly. Using this more complete sample, we confirm previous findings that the GRB rate at high redshift (z {approx}> 3) appears to be in excess of predictions based on assumptions that it should follow conventional determinations of the star formation history of the universe, combined with an estimate of its likely metallicity dependence. This suggests that either star formation at high redshifts has been significantly underestimated, for example, due to a dominant contribution from faint, undetected galaxies, or that GRB production is enhanced in the conditions of early star formation, beyond that usually ascribed to lower metallicity.

CONSTRAINTS ON OBSCURED STAR FORMATION IN HOST GALAXIES OF GAMMA-RAY BURSTS

International Nuclear Information System (INIS)

Hatsukade, Bunyo; Ohta, Kouji; Hashimoto, Tetsuya; Nakanishi, Kouichiro; Tamura, Yoichi; Kohno, Kotaro

2012-01-01

We present the results of the 16 cm wave band continuum observations of four host galaxies of gamma-ray bursts (GRBs) 990705, 021211, 041006, and 051022 using the Australia Telescope Compact Array. Radio emission was not detected in any of the host galaxies. The 2σ upper limits on star formation rates derived from the radio observations of the host galaxies are 23, 45, 27, and 26 M ☉ yr –1 , respectively, which are less than about 10 times those derived from UV/optical observations, suggesting that they have no significant dust-obscured star formation. GRBs 021211 and 051022 are known as the so-called dark GRBs and our results imply that dark GRBs do not always occur in galaxies enshrouded by dust. Because large dust extinction was not observed in the afterglow of GRB 021211, our result suggests the possibility that the cause of the dark GRB is the intrinsic faintness of the optical afterglow. On the other hand, by considering the high column density observed in the afterglow of GRB 051022, the likely cause of the dark GRB is the dust extinction in the line of sight of the GRB.

Spectroscopy of the short-hard GRB 130603B

DEFF Research Database (Denmark)

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

2014-01-01

with the Galactic ratio, indicating that the explosion site differs from those found in LGRBs. The merger is not associated with the most star-forming region of the galaxy; however, it did occur in a dense region, implying a rapid merger or a low natal kick velocity for the compact object binary........3565+/-0.0002, measure rich dynamics both in absorption and emission, and a substantial line of sight extinction of A_V = 0.86+/-0.15 mag. The GRB was located at the edge of a disrupted arm of a moderately star forming galaxy with near-solar metallicity. Unlike for most long GRBs (LGRBs), N_HX / A_V is consistent...

Evidence of deterministic components in the apparent randomness of GRBs: clues of a chaotic dynamic.

Science.gov (United States)

Greco, G; Rosa, R; Beskin, G; Karpov, S; Romano, L; Guarnieri, A; Bartolini, C; Bedogni, R

2011-01-01

Prompt γ-ray emissions from gamma-ray bursts (GRBs) exhibit a vast range of extremely complex temporal structures with a typical variability time-scale significantly short - as fast as milliseconds. This work aims to investigate the apparent randomness of the GRB time profiles making extensive use of nonlinear techniques combining the advanced spectral method of the Singular Spectrum Analysis (SSA) with the classical tools provided by the Chaos Theory. Despite their morphological complexity, we detect evidence of a non stochastic short-term variability during the overall burst duration - seemingly consistent with a chaotic behavior. The phase space portrait of such variability shows the existence of a well-defined strange attractor underlying the erratic prompt emission structures. This scenario can shed new light on the ultra-relativistic processes believed to take place in GRB explosions and usually associated with the birth of a fast-spinning magnetar or accretion of matter onto a newly formed black hole.

GRB physics and cosmology with peak energy-intensity correlations

Energy Technology Data Exchange (ETDEWEB)

Sawant, Disha, E-mail: sawant@fe.infn.it [University of Ferrara, Via Saragat-1, Block C, Ferrara 44122 (Italy); University of Nice, 28 Avenue Valrose, Nice 06103 (France); IRAP Erasmus PhD Program, European Union and INAF - IASF Bologna, Via P. Gobetti 101, Bologna 41125 (Italy); Amati, Lorenzo, E-mail: amati@iasfbo.inaf.it [INAF - IASF Bologna, Via P. Gobetti 101, Bologna 41125 (Italy); ICRANet, Piazzale Aldo Moro-5, Rome 00185 (Italy)

2015-12-17

Gamma Ray Bursts (GRBs) are immensely energetic explosions radiating up to 10{sup 54} erg of energy isotropically (E{sub iso}) and they are observed within a wide range of redshift (from ∼ 0.01 up to ∼ 9). Such enormous power and high redshift point at these phenomena being highly favorable to investigate the history and evolution of our universe. The major obstacle in their application as cosmological study-tools is to find a way to standardize the GRBs, for instance similar to SNe Ia. With respect to this goal, the correlation between spectral peak energy (E{sub p,i}) and the “intensity” is a positively useful and investigated criterion. Moreover, it has been demonstrated that, through the E{sub p,i} – E{sub iso} correlation, the current data set of GRBs can already contribute to the independent evidence of the matter density Ω{sub M} being ∼ 0.3 for a flat universe scenario. We try to inspect and compare the correlations of E{sub p,i} with different intensity indicators (e.g., radiated energy, average and peak luminosity, bolometric vs. monochromatic quantities, etc.) both in terms of intrinsic dispersion and precise estimation of Ω{sub M}. The outcome of such studies are further analyzed in verifying the reliability of the correlations for both GRB physics and their standardization for cosmology.

A MATURE DUSTY STAR-FORMING GALAXY HOSTING GRB 080607 AT z = 3.036

International Nuclear Information System (INIS)

Chen, Hsiao-Wen; Perley, Daniel A.; Cenko, S. Bradley; Bloom, Joshua S.; Wilson, Christine D.; Levan, Andrew J.; Prochaska, Jason X.; Tanvir, Nial R.; Dessauges-Zavadsky, Miroslava; Pettini, Max

2010-01-01

We report the discovery of the host galaxy of Swift dark burst GRB 080607 at z GRB = 3.036. GRB 080607 is a unique case of a highly extinguished (A V ∼ 3 mag) afterglow that was yet sufficiently bright for high-quality absorption-line spectroscopy. The host galaxy is clearly resolved in deep Hubble Space Telescope (HST) WF3/IR F160W images and well detected in the Spitzer IRAC 3.5 μm and 4.5 μm channels, while displaying little/no fluxes in deep optical images from Keck and Magellan. The extremely red optical-infrared colors are consistent with the large extinction seen in the afterglow light, suggesting that the large amount of dust and gas surface mass density seen along the afterglow sight line is not merely local but likely reflects the global dust content across the entire host galaxy. Adopting the dust properties and metallicity of the host interstellar medium derived from studies of early-time afterglow light and absorption-line spectroscopy, we perform a stellar population synthesis analysis of the observed spectral energy distribution to constrain the intrinsic luminosity and stellar population of this dark burst host. The host galaxy is best described by an exponentially declining star formation rate of e-folding time τ = 2 Gyr and an age of ∼2 Gyr. We also derive an extinction-corrected star formation rate of SFR ∼ 125 h -2 M sun yr -1 and a total stellar mass of M * ∼ 4 x 10 11 h -2 M sun . Our study provides an example of massive, dusty star-forming galaxies contributing to the γ-ray burst (GRB) host galaxy population, supporting the notion that long-duration GRBs trace the bulk of cosmic star formation.

Broadband observations of the naked-eye gamma-ray burst GRB 080319B.

Science.gov (United States)

Racusin, J L; Karpov, S V; Sokolowski, M; Granot, J; Wu, X F; Pal'shin, V; Covino, S; van der Horst, A J; Oates, S R; Schady, P; Smith, R J; Cummings, J; Starling, R L C; Piotrowski, L W; Zhang, B; Evans, P A; Holland, S T; Malek, K; Page, M T; Vetere, L; Margutti, R; Guidorzi, C; Kamble, A P; Curran, P A; Beardmore, A; Kouveliotou, C; Mankiewicz, L; Melandri, A; O'Brien, P T; Page, K L; Piran, T; Tanvir, N R; Wrochna, G; Aptekar, R L; Barthelmy, S; Bartolini, C; Beskin, G M; Bondar, S; Bremer, M; Campana, S; Castro-Tirado, A; Cucchiara, A; Cwiok, M; D'Avanzo, P; D'Elia, V; Valle, M Della; de Ugarte Postigo, A; Dominik, W; Falcone, A; Fiore, F; Fox, D B; Frederiks, D D; Fruchter, A S; Fugazza, D; Garrett, M A; Gehrels, N; Golenetskii, S; Gomboc, A; Gorosabel, J; Greco, G; Guarnieri, A; Immler, S; Jelinek, M; Kasprowicz, G; La Parola, V; Levan, A J; Mangano, V; Mazets, E P; Molinari, E; Moretti, A; Nawrocki, K; Oleynik, P P; Osborne, J P; Pagani, C; Pandey, S B; Paragi, Z; Perri, M; Piccioni, A; Ramirez-Ruiz, E; Roming, P W A; Steele, I A; Strom, R G; Testa, V; Tosti, G; Ulanov, M V; Wiersema, K; Wijers, R A M J; Winters, J M; Zarnecki, A F; Zerbi, F; Mészáros, P; Chincarini, G; Burrows, D N

2008-09-11

Long-duration gamma-ray bursts (GRBs) release copious amounts of energy across the entire electromagnetic spectrum, and so provide a window into the process of black hole formation from the collapse of massive stars. Previous early optical observations of even the most exceptional GRBs (990123 and 030329) lacked both the temporal resolution to probe the optical flash in detail and the accuracy needed to trace the transition from the prompt emission within the outflow to external shocks caused by interaction with the progenitor environment. Here we report observations of the extraordinarily bright prompt optical and gamma-ray emission of GRB 080319B that provide diagnostics within seconds of its formation, followed by broadband observations of the afterglow decay that continued for weeks. We show that the prompt emission stems from a single physical region, implying an extremely relativistic outflow that propagates within the narrow inner core of a two-component jet.

Statistical properties of Fermi GBM GRBs' spectra

Science.gov (United States)

Rácz, István I.; Balázs, Lajos G.; Horvath, Istvan; Tóth, L. Viktor; Bagoly, Zsolt

2018-03-01

Statistical studies of gamma-ray burst (GRB) spectra may result in important information on the physics of GRBs. The Fermi GBM catalogue contains GRB parameters (peak energy, spectral indices, and intensity) estimated fitting the gamma-ray spectral energy distribution of the total emission (fluence, flnc), and during the time of the peak flux (pflx). Using contingency tables, we studied the relationship of the models best-fitting pflx and flnc time intervals. Our analysis revealed an ordering of the spectra into a power law - Comptonized - smoothly broken power law - Band series. This result was further supported by a correspondence analysis of the pflx and flnc spectra categorical variables. We performed a linear discriminant analysis (LDA) to find a relationship between categorical (spectral) and model independent physical data. LDA resulted in highly significant physical differences among the spectral types, that is more pronounced in the case of the pflx spectra, than for the flnc spectra. We interpreted this difference as caused by the temporal variation of the spectrum during the outburst. This spectral variability is confirmed by the differences in the low-energy spectral index and peak energy, between the pflx and flnc spectra. We found that the synchrotron radiation is significant in GBM spectra. The mean low-energy spectral index is close to the canonical value of α = -2/3 during the peak flux. However, α is ˜ -0.9 for the spectra of the fluences. We interpret this difference as showing that the effect of cooling is important only for the fluence spectra.

The afterglow of GRB 050709 and the nature of the short-hard gamma-ray bursts.

Science.gov (United States)

Fox, D B; Frail, D A; Price, P A; Kulkarni, S R; Berger, E; Piran, T; Soderberg, A M; Cenko, S B; Cameron, P B; Gal-Yam, A; Kasliwal, M M; Moon, D-S; Harrison, F A; Nakar, E; Schmidt, B P; Penprase, B; Chevalier, R A; Kumar, P; Roth, K; Watson, D; Lee, B L; Shectman, S; Phillips, M M; Roth, M; McCarthy, P J; Rauch, M; Cowie, L; Peterson, B A; Rich, J; Kawai, N; Aoki, K; Kosugi, G; Totani, T; Park, H-S; MacFadyen, A; Hurley, K C

2005-10-06

The final chapter in the long-standing mystery of the gamma-ray bursts (GRBs) centres on the origin of the short-hard class of bursts, which are suspected on theoretical grounds to result from the coalescence of neutron-star or black-hole binary systems. Numerous searches for the afterglows of short-hard bursts have been made, galvanized by the revolution in our understanding of long-duration GRBs that followed the discovery in 1997 of their broadband (X-ray, optical and radio) afterglow emission. Here we present the discovery of the X-ray afterglow of a short-hard burst, GRB 050709, whose accurate position allows us to associate it unambiguously with a star-forming galaxy at redshift z = 0.160, and whose optical lightcurve definitively excludes a supernova association. Together with results from three other recent short-hard bursts, this suggests that short-hard bursts release much less energy than the long-duration GRBs. Models requiring young stellar populations, such as magnetars and collapsars, are ruled out, while coalescing degenerate binaries remain the most promising progenitor candidates.

GRB follow-up observations in the East-Asian region

International Nuclear Information System (INIS)

Tamagawa, T.; Urata, Y.; Tokyo Institute of Technology, Tokyo; Huang, K. Y.; Ip, W.H.; Qiu, Y.; Hu, J.Y.; Zhou, Xn.; Onda, K.; Tokyo Univ. of Sciences, Tokyo; Makishima, K.; Tokyo Univ., Tokyo

2005-01-01

In 2004, we established a Japan-Taiwan-China collaboration for GBR study in the East-Asian region. This serves as a valuable addiction to the world-wide optical and infrared follow-up network, because the East-Asia region would otherwise be blank. We have been carrying out imaging and spectroscopy follow-up observations at Lulin (Taiwan), Kiso (Japan), WIDGET (Japan) and Xinglong (China). From Xinglong and Kiso, we can locate candidates and obtain early time spectra for afterglows. While WIDGET provides early time observations before the bursts, the high-time resolution for multi-band light curves can be obtained at Lulin. With the data from these sites, we can obtain detailed information about the light curve and redshift of GRBs, which are important to understand the mechanism of the afterglows. Up to March 2005, ten follow-up observations have been provided by this East-Asia cooperation. Two optical afterglows were detected, GRB 040924 and GRB 041006. The results of the two detected afterglows are reported in this paper

GRB follow-up observations in the East-Asian region

Energy Technology Data Exchange (ETDEWEB)

Tamagawa, T. [RIKEN, Saitama (Japan); Urata, Y. [RIKEN, Saitama (Japan); Tokyo Institute of Technology, Tokyo (Japan). Department of Physics; Huang, K. Y.; Ip, W.H. [National Centre University, Tokyo (Japan). Institute of Astronomy; Qiu, Y.; Hu, J.Y.; Zhou, Xn. [Chinese Academy of Sciences, Beijing (China). National Astronomical Observatoires; Onda, K. [RIKEN, Saitama (Japan); Tokyo Univ. of Sciences, Tokyo (Japan). Department of Physics; Makishima, K. [RIKEN, Saitama (Japan); Tokyo Univ., Tokyo (Japan). Department of Physics

2005-07-15

In 2004, we established a Japan-Taiwan-China collaboration for GBR study in the East-Asian region. This serves as a valuable addiction to the world-wide optical and infrared follow-up network, because the East-Asia region would otherwise be blank. We have been carrying out imaging and spectroscopy follow-up observations at Lulin (Taiwan), Kiso (Japan), WIDGET (Japan) and Xinglong (China). From Xinglong and Kiso, we can locate candidates and obtain early time spectra for afterglows. While WIDGET provides early time observations before the bursts, the high-time resolution for multi-band light curves can be obtained at Lulin. With the data from these sites, we can obtain detailed information about the light curve and redshift of GRBs, which are important to understand the mechanism of the afterglows. Up to March 2005, ten follow-up observations have been provided by this East-Asia cooperation. Two optical afterglows were detected, GRB 040924 and GRB 041006. The results of the two detected afterglows are reported in this paper.

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.

Method for detecting neutrinos from internal shocks in GRB fireballs with AMANDA

CERN Document Server

Stamatikos, M

2004-01-01

Neutrino-based astronomy provides a new window on the most energetic processes in the universe. The discovery of high-energy (E >or= 10 /sup 14/ eV) muonic neutrinos (v/sub mu /) from gamma-ray bursts (GRBs) would confirm hadronic acceleration in the relativistic GRB- wind, validate the phenomenology of the canonical fireball model and possibly reveal an acceleration mechanism for the highest energy cosmic rays (CRs). The Antarctic Muon and Neutrino Detector Array (AMANDA) is the world's largest operational neutrino telescope with a PeV muon effective area (averaged over zenith angle) ~ 50,000 m/sup 2 /. AMANDA uses the natural ice at the geographic South Pole as a Cherenkov medium and has been successfully calibrated on the signal of atmospheric neutrinos (v/sub atm/). Contrary to previous diffuse searches, we describe an analysis based upon confronting AMANDA observations of individual GRBs, adequately modeled by fireball phenomenology, with the predictions of the canonical fireball model. The expected neut...

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.;

GRB 080503 LATE AFTERGLOW RE-BRIGHTENING: SIGNATURE OF A MAGNETAR-POWERED MERGER-NOVA

International Nuclear Information System (INIS)

Gao, He; Ding, Xuan; Wu, Xue-Feng; Dai, Zi-Gao; Zhang, Bing

2015-01-01

GRB 080503 is a short gamma-ray burst (GRB) detected by Swift and has been classified as a GRB originating from a compact star merger. The soft extended emission and the simultaneous late re-brightening in both the X-ray and optical afterglow light curves raise interesting questions regarding its physical origin. We show that the broadband 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. The X-ray emission initially leaks from a hole in the merger ejecta pierced by the short GRB jet. The hole subsequently closes after the magnetar spins down and the magnetic pressure drops below ram pressure. The X-ray photons are then trapped behind the merger-nova ejecta until the ejecta becomes optically thin at a later time. This explains the essentially simultaneous re-brightening in both the optical and X-ray light curves. Within this model, future gravitational-wave sources could be associated with a bright X-ray counterpart along with the merger-nova, even if the short GRB jet beams away from Earth

The Arcminute Microkelvin Imager catalogue of gamma-ray burst afterglows at 15.7 GHz

Science.gov (United States)

Anderson, G. E.; Staley, T. D.; van der Horst, A. J.; Fender, R. P.; Rowlinson, A.; Mooley, K. P.; Broderick, J. W.; Wijers, R. A. M. J.; Rumsey, C.; Titterington, D. J.

2018-01-01

We present the Arcminute Microkelvin Imager (AMI) Large Array catalogue of 139 gamma-ray bursts (GRBs). AMI observes at a central frequency of 15.7 GHz and is equipped with a fully automated rapid-response mode, which enables the telescope to respond to high-energy transients detected by Swift. On receiving a transient alert, AMI can be on-target within 2 min, scheduling later start times if the source is below the horizon. Further AMI observations are manually scheduled for several days following the trigger. The AMI GRB programme probes the early-time (<1 d) radio properties of GRBs, and has obtained some of the earliest radio detections (GRB 130427A at 0.36 and GRB 130907A at 0.51 d post-burst). As all Swift GRBs visible to AMI are observed, this catalogue provides the first representative sample of GRB radio properties, unbiased by multiwavelength selection criteria. We report the detection of six GRB radio afterglows that were not previously detected by other radio telescopes, increasing the rate of radio detections by 50 per cent over an 18-month period. The AMI catalogue implies a Swift GRB radio detection rate of ≳ 15 per cent, down to ∼0.2 mJy beam-1. However, scaling this by the fraction of GRBs AMI would have detected in the Chandra & Frail sample (all radio-observed GRBs between 1997 and 2011), it is possible ∼ 44-56 per cent of Swift GRBs are radio bright, down to ∼0.1-0.15 mJy beam-1. This increase from the Chandra & Frail rate (∼30 per cent) is likely due to the AMI rapid-response mode, which allows observations to begin while the reverse-shock is contributing to the radio afterglow.

THE LATE PEAKING AFTERGLOW OF GRB 100418A

International Nuclear Information System (INIS)

Marshall, F. E.; Holland, S. T.; Sakamoto, T.; Antonelli, L. A.; Burrows, D. N.; Siegel, M. H.; Covino, S.; Fugazza, D.; De Pasquale, M.; Oates, S. R.; Evans, P. A.; O'Brien, P. T.; Osborne, J. P.; Pagani, C.; Liang, E. W.; Wu, X. F.; Zhang, B.

2011-01-01

GRB 100418A is a long gamma-ray burst (GRB) at redshift z = 0.6235 discovered with the Swift Gamma-ray Burst Explorer with unusual optical and X-ray light curves. After an initial short-lived, rapid decline in X-rays, the optical and X-ray light curves observed with Swift are approximately flat or rising slightly out to at least ∼7 x 10 3 s after the trigger, peak at ∼5 x 10 4 s, and then follow an approximately power-law decay. Such a long optical plateau and late peaking is rarely seen in GRB afterglows. Observations with Rapid Eye Mount during a gap in the Swift coverage indicate a bright optical flare at ∼2.5 x 10 4 s. The long plateau phase of the afterglow is interpreted using either a model with continuous injection of energy into the forward shock of the burst or a model in which the jet of the burst is viewed off-axis. In both models the isotropic kinetic energy in the late afterglow after the plateau phase is ≥10 2 times the 10 51 erg of the prompt isotropic gamma-ray energy release. The energy injection model is favored because the off-axis jet model would require the intrinsic T 90 for the GRB jet viewed on-axis to be very short, ∼10 ms, and the intrinsic isotropic gamma-ray energy release and the true jet energy to be much higher than the typical values of known short GRBs. The non-detection of a jet break up to t ∼ 2 x 10 6 s indicates a jet half-opening angle of at least ∼14 0 , and a relatively high-collimation-corrected jet energy of E jet ≥ 10 52 erg.

A search for neutrino and gamma ray burst temporal correlations with the IMB detector

International Nuclear Information System (INIS)

Becker-Szendy, R.; Bratton, C.B.; Breault, J.; Casper, D.; Dye, S.T.; Gajewski, W.; Goldhaber, M.; Haines, T.J.; Halverson, P.G.; Kielczewska, D.; Kropp, W.R.; Learned, J.G.; LoSecco, J.; Matsuno, S.; Matthews, J.; McGrath, G.; McGrew, C.; Miller, R.S.; Price, L.; Reines, F.; Schultz, J.; Sinclair, D.; Sobel, H.W.; Stone, J.L.; Sulak, L.R.; Svoboda, R.

1993-01-01

If Gamma Ray Bursts (GRBs) are associated with a stellar collapse-like phenomenon then it is resonable to expect neutrino production to occur at the source. We have performed a temporal correlation analysis with GRBs using the IMB low-energy neutrino dataset during 809 days of livetime between 1986 and 1990. No correlations were observed placing a 90%. C.L. limit of 0.046 ν interactions per GRB. The dependence of the GRB distances to neutrino yield using volume and shell distribution models is discussed. Lower limits are derived which exclude galactic stellar collapse-like models

THE THIRD SWIFT BURST ALERT TELESCOPE GAMMA-RAY BURST CATALOG

Energy Technology Data Exchange (ETDEWEB)

Lien, Amy; Baumgartner, Wayne H.; Cannizzo, John K.; Collins, Nicholas R.; Krimm, Hans A.; Troja, Eleonora [Center for Research and Exploration in Space Science and Technology (CRESST) and NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Sakamoto, Takanori [Department of Physics and Mathematics, College of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara-shi, Kanagawa 252-5258 (Japan); Barthelmy, Scott D.; Cummings, Jay R.; Gehrels, Neil; Markwardt, Craig B. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Chen, Kevin [Department of Physics, University of California, Berkeley, 366 LeConte Hall MC 7300, Berkeley, CA 9472 (United States); Palmer, David M.; Ukwatta, T. N. [Space and Remote Sensing (ISR-2), Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Stamatikos, Michael [Department of Physics, Department of Astronomy and Center for Cosmology and AstroParticle Physics, Ohio State University, Columbus, OH 43210 (United States)

2016-09-20

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 GRB 151027B. 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 emission beyond ∼1000 s of event data, and only two GRBs (GRB 100316D and GRB 101024A) with detections in the survey data prior to the starting of event data.

HOST GALAXY PROPERTIES OF THE SUBLUMINOUS GRB 120422A/SN 2012bz

Energy Technology Data Exchange (ETDEWEB)

Levesque, Emily M. [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado 389-UCB, Boulder, CO 80309 (United States); Chornock, Ryan; Soderberg, Alicia M.; Berger, Edo; Lunnan, Ragnhild, E-mail: Emily.Levesque@colorado.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2012-10-20

GRB 120422A is a nearby (z = 0.283) long-duration gamma-ray burst (LGRB) detected by Swift with E {sub {gamma},iso} {approx} 4.5 Multiplication-Sign 10{sup 49} erg. It is also associated with the spectroscopically confirmed broad-lined Type Ic SN 2012bz. These properties establish GRB 120422A/SN 2012bz as the sixth and newest member of the class of subluminous GRBs supernovae (SNe). Observations also show that GRB 120422A/SN 2012bz occurred at an unusually large offset ({approx}8 kpc) from the host galaxy nucleus, setting it apart from other nearby LGRBs and leading to speculation that the host environment may have undergone prior interaction activity. Here, we present spectroscopic observations using the 6.5 m Magellan telescope at Las Campanas. We extract spectra at three specific locations within the GRB/SN host galaxy, including the host nucleus, the explosion site, and the 'bridge' of diffuse emission connecting these two regions. We measure a metallicity of log(O/H) + 12 = 8.3 {+-} 0.1 and a star formation rate (SFR) per unit area of 0.08 M {sub Sun} yr{sup -1} kpc{sup -2} at the host nucleus. At the GRB/SN explosion site we measure a comparable metallicity of log(O/H) + 12 = 8.2 {+-} 0.1 but find a much lower SFR per unit area of 0.01 M {sub Sun} yr{sup -1} kpc{sup -2}. We also compare the host galaxy of this event to the hosts of other LGRBs, including samples of subluminous LGRBs and cosmological LGRBs, and find no systematic metallicity difference between the environments of these different subtypes.

THE NEEDLE IN THE 100 deg{sup 2} HAYSTACK: UNCOVERING AFTERGLOWS OF FERMI GRBs WITH THE PALOMAR TRANSIENT FACTORY

Energy Technology Data Exchange (ETDEWEB)

Singer, Leo P. [LIGO Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States); Kasliwal, Mansi M. [Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena CA 91101 (United States); Cenko, S. Bradley; Cucchiara, Antonino; Gehrels, Neil [Astrophysics Science Division, NASA Goddard Space Flight Center, Code 661, Greenbelt, MD 20771 (United States); Perley, Daniel A.; Cao, Yi [Cahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Anderson, Gemma E.; Fender, Rob P. [Astrophysics, Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Anupama, G. C. [Indian Institute of Astrophysics, Koramangala, Bangalore 560 034 (India); Arcavi, Iair [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Bhalerao, Varun [Inter-University Centre for Astronomy and Astrophysics (IUCAA), Post Bag 4, Ganeshkhind, Pune 411007 (India); Bue, Brian D. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Connaughton, Valerie [CSPAR and Physics Department, University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35899 (United States); Corsi, Alessandra [Texas Tech University, Physics Department, Lubbock, TX 79409-1051 (United States); Fox, Derek B. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Goldstein, Adam [Astrophysics Office, ZP12, NASA Marshall Space Flight Center, Huntsville, AL 35812 (United States); Gorosabel, J. [Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, E-18008, Granada (Spain); Horesh, Assaf, E-mail: leo.p.singer@nasa.gov [Benoziyo Center for Astrophysics, Weizmann Institute of Science, 76100 Rehovot (Israel); and others

2015-06-10

The Fermi Gamma-ray Space Telescope has greatly expanded the number and energy window of observations of gamma-ray bursts (GRBs). However, the coarse localizations of tens to a hundred square degrees provided by the Fermi GRB Monitor instrument have posed a formidable obstacle to locating the bursts’ host galaxies, measuring their redshifts, and tracking their panchromatic afterglows. We have built a target-of-opportunity mode for the intermediate Palomar Transient Factory in order to perform targeted searches for Fermi afterglows. Here, we present the results of one year of this program: 8 afterglow discoveries out of 35 searches. Two of the bursts with detected afterglows (GRBs 130702A and 140606B) were at low redshift (z = 0.145 and 0.384, respectively) and had spectroscopically confirmed broad-line Type Ic supernovae. We present our broadband follow-up including spectroscopy as well as X-ray, UV, optical, millimeter, and radio observations. We study possible selection effects in the context of the total Fermi and Swift GRB samples. We identify one new outlier on the Amati relation. We find that two bursts are consistent with a mildly relativistic shock breaking out from the progenitor star rather than the ultra-relativistic internal shock mechanism that powers standard cosmological bursts. Finally, in the context of the Zwicky Transient Facility, we discuss how we will continue to expand this effort to find optical counterparts of binary neutron star mergers that may soon be detected by Advanced LIGO and Virgo.

A very energetic supernova associated with the gamma-ray burst of 29 March 2003.

Science.gov (United States)

Hjorth, Jens; Sollerman, Jesper; Møller, Palle; Fynbo, Johan P U; Woosley, Stan E; Kouveliotou, Chryssa; Tanvir, Nial R; Greiner, Jochen; Andersen, Michael I; Castro-Tirado, Alberto J; Castro Cerón, José María; Fruchter, Andrew S; Gorosabel, Javier; Jakobsson, Páll; Kaper, Lex; Klose, Sylvio; Masetti, Nicola; Pedersen, Holger; Pedersen, Kristian; Pian, Elena; Palazzi, Eliana; Rhoads, James E; Rol, Evert; van den Heuvel, Edward P J; Vreeswijk, Paul M; Watson, Darach; Wijers, Ralph A M J

2003-06-19

Over the past five years evidence has mounted that long-duration (>2 s) gamma-ray bursts (GRBs)-the most luminous of all astronomical explosions-signal the collapse of massive stars in our Universe. This evidence was originally based on the probable association of one unusual GRB with a supernova, but now includes the association of GRBs with regions of massive star formation in distant galaxies, the appearance of supernova-like 'bumps' in the optical afterglow light curves of several bursts and lines of freshly synthesized elements in the spectra of a few X-ray afterglows. These observations support, but do not yet conclusively demonstrate, the idea that long-duration GRBs are associated with the deaths of massive stars, presumably arising from core collapse. Here we report evidence that a very energetic supernova (a hypernova) was temporally and spatially coincident with a GRB at redshift z = 0.1685. The timing of the supernova indicates that it exploded within a few days of the GRB, strongly suggesting that core-collapse events can give rise to GRBs, thereby favouring the 'collapsar' model.

A short gamma-ray burst apparently associated with an elliptical galaxy at redshift z = 0.225.

Science.gov (United States)

Gehrels, N; Sarazin, C L; O'Brien, P T; Zhang, B; Barbier, L; Barthelmy, S D; Blustin, A; Burrows, D N; Cannizzo, J; Cummings, J R; Goad, M; Holland, S T; Hurkett, C P; Kennea, J A; Levan, A; Markwardt, C B; Mason, K O; Meszaros, P; Page, M; Palmer, D M; Rol, E; Sakamoto, T; Willingale, R; Angelini, L; Beardmore, A; Boyd, P T; Breeveld, A; Campana, S; Chester, M M; Chincarini, G; Cominsky, L R; Cusumano, G; de Pasquale, M; Fenimore, E E; Giommi, P; Gronwall, C; Grupe, D; Hill, J E; Hinshaw, D; Hjorth, J; Hullinger, D; Hurley, K C; Klose, S; Kobayashi, S; Kouveliotou, C; Krimm, H A; Mangano, V; Marshall, F E; McGowan, K; Moretti, A; Mushotzky, R F; Nakazawa, K; Norris, J P; Nousek, J A; Osborne, J P; Page, K; Parsons, A M; Patel, S; Perri, M; Poole, T; Romano, P; Roming, P W A; Rosen, S; Sato, G; Schady, P; Smale, A P; Sollerman, J; Starling, R; Still, M; Suzuki, M; Tagliaferri, G; Takahashi, T; Tashiro, M; Tueller, J; Wells, A A; White, N E; Wijers, R A M J

2005-10-06

Gamma-ray bursts (GRBs) come in two classes: long (> 2 s), soft-spectrum bursts and short, hard events. Most progress has been made on understanding the long GRBs, which are typically observed at high redshift (z approximately 1) and found in subluminous star-forming host galaxies. They are likely to be produced in core-collapse explosions of massive stars. In contrast, no short GRB had been accurately (burst GRB 050509B. Its position on the sky is near a luminous, non-star-forming elliptical galaxy at a redshift of 0.225, which is the location one would expect if the origin of this GRB is through the merger of neutron-star or black-hole binaries. The X-ray afterglow was weak and faded below the detection limit within a few hours; no optical afterglow was detected to stringent limits, explaining the past difficulty in localizing short GRBs.

CONSTRAINTS ON THE EMISSION MODEL OF THE 'NAKED-EYE BURST' GRB 080319B

International Nuclear Information System (INIS)

Abdo, A. A.; Abeysekara, A. U.; Linnemann, J. T.; Allen, B. T.; Chen, C.; Aune, T.; Berley, D.; Goodman, J. A.; Christopher, G. E.; Kolterman, B. E.; Mincer, A. I.; DeYoung, T.; Dingus, B. L.; Hoffman, C. M.; Ellsworth, R. W.; Gonzalez, M. M.; Granot, J.; Hays, E.; McEnery, J. E.; Hüntemeyer, P. H.

2012-01-01

On 2008 March 19, one of the brightest gamma-ray bursts (GRBs) ever recorded was detected by several ground- and space-based instruments spanning the electromagnetic spectrum from radio to gamma rays. With a peak visual magnitude of 5.3, GRB 080319B was dubbed the 'naked-eye' GRB, as an observer under dark skies could have seen the burst without the aid of an instrument. Presented here are results from observations of the prompt phase of GRB 080319B taken with the Milagro TeV observatory. The burst was observed at an elevation angle of 47°. Analysis of the data is performed using both the standard air shower method and the scaler or single-particle technique, which results in a sensitive energy range that extends from ∼5 GeV to >20 TeV. These observations provide the only direct constraints on the properties of the high-energy gamma-ray emission from GRB 080319B at these energies. No evidence for emission is found in the Milagro data, and upper limits on the gamma-ray flux above 10 GeV are derived. The limits on emission between ∼25 and 200 GeV are incompatible with the synchrotron self-Compton model of gamma-ray production and disfavor a corresponding range (2 eV-16 eV) of assumed synchrotron peak energies. This indicates that the optical photons and soft (∼650 keV) gamma rays may not be produced by the same electron population.

Search for high-energy muon neutrinos from the "naked-eye" GRB 080319B with the IceCube neutrino telescope

DEFF Research Database (Denmark)

Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.

2009-01-01

We report on a search with the IceCube detector for high-energy muon neutrinos from GRB 080319B, one of the brightest gamma-ray bursts (GRBs) ever observed. The fireball model predicts that a mean of 0.1 events should be detected by IceCube for a bulk Lorentz boost of the jet of 300. In both the ......V and 2.2 PeV, which contains 90% of the expected events....

The sub-energetic gamma-ray burst GRB 031203 as a cosmic analogue to the nearby GRB 980425.

Science.gov (United States)

Soderberg, A M; Kulkarni, S R; Berger, E; Fox, D W; Sako, M; Frail, D A; Gal-Yam, A; Moon, D S; Cenko, S B; Yost, S A; Phillips, M M; Persson, S E; Freedman, W L; Wyatt, P; Jayawardhana, R; Paulson, D

2004-08-05

Over the six years since the discovery of the gamma-ray burst GRB 980425, which was associated with the nearby (distance approximately 40 Mpc) supernova 1998bw, astronomers have debated fiercely the nature of this event. Relative to bursts located at cosmological distance (redshift z approximately 1), GRB 980425 was under-luminous in gamma-rays by three orders of magnitude. Radio calorimetry showed that the explosion was sub-energetic by a factor of 10. Here we report observations of the radio and X-ray afterglow of the recent GRB 031203 (refs 5-7), which has a redshift of z = 0.105. We demonstrate that it too is sub-energetic which, when taken together with the low gamma-ray luminosity, suggests that GRB 031203 is the first cosmic analogue to GRB 980425. We find no evidence that this event was a highly collimated explosion viewed off-axis. Like GRB 980425, GRB 031203 appears to be an intrinsically sub-energetic gamma-ray burst. Such sub-energetic events have faint afterglows. We expect intensive follow-up of faint bursts with smooth gamma-ray light curves (common to both GRB 031203 and 980425) to reveal a large population of such events.

Broad band simulation of Gamma Ray Bursts (GRB) prompt emission in presence of an external magnetic field

Science.gov (United States)

Ziaeepour, Houri; Gardner, Brian

2011-12-01

The origin of prompt emission in GRBs is not yet well understood. The simplest and most popular model is Synchrotron Self-Compton (SSC) emission produced by internal shocks inside an ultra-relativistic jet. However, recent observations of a delayed high energy component by the Fermi-LAT instrument have encouraged alternative models. Here we use a recently developed formulation of relativistic shocks for GRBs to simulate light curves and spectra of synchrotron and self-Compton emissions in the framework of internal shock model. This model takes into account the evolution of quantities such as densities of colliding shells, and fraction of kinetic energy transferred to electrons and to induced magnetic field. We also extend this formulation by considering the presence of a precessing external magnetic field. These simulations are very realistic and present significant improvement with respect to previous phenomenological GRB simulations. They reproduce light curves of separate peaks of real GRBs and variety of spectral slopes at E > Epeak observed by the Fermi-LAT instrument. The high energy emission can be explained by synchrotron emission and a subdominant contribution from inverse Compton. We also suggest an explanation for extended tail emission and relate it to the screening of the magnetic field and/or trapping of accelerated electrons in the electromagnetic energy structure of the plasma in the shock front. Spectral slopes of simulated bursts at E external magnetic field, we show that due to the fast variation of other quantities, its signature in the Power Distribution Spectrum (PDS) is significantly suppressed and only when the duration of the burst is few times longer than the oscillation period it can be detected, otherwise either it is confused with the Poisson noise or with intrinsic variations of the emission. Therefore, low significant oscillations observed in the PDS of GRB 090709a are most probably due to a precessing magnetic field.

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

International Nuclear Information System (INIS)

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

2013-01-01

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

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

THE AFTERGLOW AND ULIRG HOST GALAXY OF THE DARK SHORT GRB 120804A

International Nuclear Information System (INIS)

Berger, E.; Zauderer, B. A.; Margutti, R.; Laskar, T.; Fong, W.; Chornock, R.; Dupuy, T. J.; Levan, A.; Tunnicliffe, R. L.; Mangano, V.; Fox, D. B.; Tanvir, N. R.; Menten, K. M.; Hjorth, J.; Roth, K.

2013-01-01

We present the optical discovery and subarcsecond optical and X-ray localization of the afterglow of the short GRB 120804A, as well as optical, near-IR, and radio detections of its host galaxy. X-ray observations with Swift/XRT, Chandra, and XMM-Newton extending to δt ≈ 19 days reveal a single power-law decline. The optical afterglow is faint, and comparison to the X-ray flux indicates that GRB 120804A is ''dark'', with a rest-frame extinction of A host V ≈ 2.5 mag (at z = 1.3). The intrinsic neutral hydrogen column density inferred from the X-ray spectrum, N H, i nt (z = 1.3) ≈ 2 × 10 22 cm –2 , is commensurate with the large extinction. The host galaxy exhibits red optical/near-IR colors. Equally important, JVLA observations at ≈0.9-11 days reveal a constant flux density of F ν (5.8 GHz) = 35 ± 4 μJy and an optically thin spectrum, unprecedented for GRB afterglows, but suggestive instead of emission from the host galaxy. The optical/near-IR and radio fluxes are well fit with the scaled spectral energy distribution of the local ultraluminous infrared galaxy (ULIRG) Arp 220 at z ≈ 1.3, with a resulting star formation rate of x ≈ 300 M ☉ yr –1 . The inferred extinction and small projected offset (2.2 ± 1.2 kpc) are also consistent with the ULIRG scenario, as is the presence of a companion galaxy at the same redshift and with a separation of about 11 kpc. The limits on radio afterglow emission, in conjunction with the observed X-ray and optical emission, require a circumburst density of n ∼ 10 –3 cm –3 , an isotropic-equivalent energy scale of E γ, i so ≈ E K, i so ≈ 7 × 10 51 erg, and a jet opening angle of θ j ∼> 11°. The expected fraction of luminous infrared galaxies in the short GRB host sample is ∼0.01 and ∼0.25 (for pure stellar mass and star formation weighting, respectively). Thus, the observed fraction of two events in about 25 hosts (GRBs 120804A and 100206A) appears to support our previous conclusion that short

IS THE LATE NEAR-INFRARED BUMP IN SHORT-HARD GRB 130603B DUE TO THE LI-PACZYNSKI KILONOVA?

International Nuclear Information System (INIS)

Jin, Zhi-Ping; Fan, Yi-Zhong; Wei, Da-Ming; Xu, Dong; Wu, Xue-Feng

2013-01-01

Short-hard gamma-ray bursts (GRBs) are widely believed to be produced by the merger of two binary compact objects, specifically by two neutron stars or by a neutron star orbiting a black hole. According to the Li-Paczynski kilonova model, the merger would launch sub-relativistic ejecta and a near-infrared/optical transient would then occur, lasting up to days, which is powered by the radioactive decay of heavy elements synthesized in the ejecta. The detection of a late bump using the Hubble Space Telescope (HST) in the near-infrared afterglow light curve of the short-hard GRB 130603B is indeed consistent with such a model. However, as shown in this Letter, the limited HST near-infrared light curve behavior can also be interpreted as the synchrotron radiation of the external shock driven by a wide mildly relativistic outflow. In such a scenario, the radio emission is expected to peak with a flux of ∼100 μJy, which is detectable for current radio arrays. Hence, the radio afterglow data can provide complementary evidence on the nature of the bump in GRB 130603B. It is worth noting that good spectroscopy during the bump phase in short-hard bursts can test the validity of either model above, analogous to spectroscopy of broad-lined Type Ic supernova in long-soft GRBs

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.;

CENTRAL ENGINE MEMORY OF GAMMA-RAY BURSTS AND SOFT GAMMA-RAY REPEATERS

International Nuclear Information System (INIS)

Zhang, Bin-Bin; Castro-Tirado, Alberto J.; Zhang, Bing

2016-01-01

Gamma-ray bursts (GRBs) are bursts of γ-rays generated from relativistic jets launched from catastrophic events such as massive star core collapse or binary compact star coalescence. Previous studies suggested that GRB emission is erratic, with no noticeable memory in the central engine. Here we report a discovery that similar light curve patterns exist within individual bursts for at least some GRBs. Applying the Dynamic Time Warping method, we show that similarity of light curve patterns between pulses of a single burst or between the light curves of a GRB and its X-ray flare can be identified. This suggests that the central engine of at least some GRBs carries “memory” of its activities. We also show that the same technique can identify memory-like emission episodes in the flaring emission in soft gamma-ray repeaters (SGRs), which are believed to be Galactic, highly magnetized neutron stars named magnetars. Such a phenomenon challenges the standard black hole central engine models for GRBs, and suggest a common physical mechanism behind GRBs and SGRs, which points toward a magnetar central engine of GRBs

ASTROBIOLOGICAL EFFECTS OF GAMMA-RAY BURSTS IN THE MILKY WAY GALAXY

International Nuclear Information System (INIS)

Gowanlock, Michael G.

2016-01-01

A planet having protective ozone within the collimated beam of a gamma-ray burst (GRB) may suffer ozone depletion, potentially causing a mass extinction event to existing life on a planet’s surface and oceans. We model the dangers of long GRBs to planets in the Milky Way and utilize a static statistical model of the Galaxy, which matches major observable properties, such as the inside-out star formation history (SFH), metallicity evolution, and three-dimensional stellar number density distribution. The GRB formation rate is a function of both the SFH and metallicity. However, the extent to which chemical evolution reduces the GRB rate over time in the Milky Way is still an open question. Therefore, we compare the damaging effects of GRBs to biospheres in the Milky Way using two models. One model generates GRBs as a function of the inside-out SFH. The other model follows the SFH, but generates GRB progenitors as a function of metallicity, thereby favoring metal-poor host regions of the Galaxy over time. If the GRB rate only follows the SFH, the majority of the GRBs occur in the inner Galaxy. However, if GRB progenitors are constrained to low-metallicity environments, then GRBs only form in the metal-poor outskirts at recent epochs. Interestingly, over the past 1 Gyr, the surface density of stars (and their corresponding planets), which survive a GRB is still greatest in the inner galaxy in both models. The present-day danger of long GRBs to life at the solar radius ( R ⊙ = 8 kpc) is low. We find that at least ∼65% of stars survive a GRB over the past 1 Gyr. Furthermore, when the GRB rate was expected to have been enhanced at higher redshifts, such as z ≳ 0.5, our results suggest that a large fraction of planets would have survived these lethal GRB events.

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

Energy Technology Data Exchange (ETDEWEB)

McGlynn, S.; Hanlon, L.; Foley, S. [College Univ., Dublin (Iran, Islamic Republic of). Department of Experimental Physics; McBreen, S. [ESTEC, Noordwijk (Netherlands). Astrophysics Mission Division, RSSD of ESA; Moran, L. [Southampton Univ., Southampton (United Kingdom). School of Physics and Astronomy; Preece, R. [Alabama Univ., Huntsville (United States); Kienlin, A. von [Max-Planck-Institut fur extraterrestrische Physik, Garching (Germany); Williams, O.R. [SCI-SDG, Noordwijk (Netherlands). Science Operation and Data Systems Division of ESA-ESTEC

2005-07-15

GRB 040223 was observed by INTEGRAL and XMM-Newton. GRB 040223 has a peak flux of (1.6{+-}0.13) x 10{sup -8} ergs cm{sup -2} s{sup -1}, a fluence of (4.4{+-}0.4) x 10{sup -7} ergs cm{sup -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 E{sub peak} < 20 keV. If E{sub peak} is < 10 keV, it would qualify as an X-ray flash with high-energy emission. The X-ray data has a spectral index {beta}{sub x} = -1.7{+-}0.2, a temporal decay of t{sup -0.75{+-}}{sup 0.25} and a large column density of 1.8 x 10{sup 22} cm{sup -2}. The luminosity-lag relationship was used to obtain a redshift z 0.1{sub -0.02}{sup +0.04}. The isotropic energy radiated in {gamma}-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.

The Signature of the Central Engine in the Weakest Relativistic Explosions: GRB 100316D

Science.gov (United States)

Margutti, R.; Soderberg, A. M.; Wieringa, M. H.; Edwards, P. G.; Chevalier, R. A.; Morsony, B. J.; Barniol Duran, R.; Sironi, L.; Zauderer, B. A.; Milisavljevic, D.; Kamble, A.; Pian, E.

2013-11-01

We present late-time radio and X-ray observations of the nearby sub-energetic gamma-ray burst (GRB)100316D associated with supernova (SN) 2010bh. Our broad-band analysis constrains the explosion properties of GRB 100316D to be intermediate between highly relativistic, collimated GRBs and the spherical, ordinary hydrogen-stripped SNe. We find that ~1049 erg is coupled to mildly relativistic (Γ = 1.5-2), quasi-spherical ejecta, expanding into a medium previously shaped by the progenitor mass-loss with a rate of \\dot{M}\\, {\\sim }\\, 10^{-5}\\,M_{\\odot }\\,yr^{-1} (for an assumed wind density profile and wind velocity vw = 1000 km s-1). The kinetic energy profile of the ejecta argues for the presence of a central engine and identifies GRB 100316D as one of the weakest central-engine-driven explosions detected to date. Emission from the central engine is responsible for an excess of soft X-ray radiation that dominates over the standard afterglow at late times (t > 10 days). We connect this phenomenology with the birth of the most rapidly rotating magnetars. Alternatively, accretion onto a newly formed black hole might explain the excess of radiation. However, significant departure from the standard fall-back scenario is required.

The signature of the central engine in the weakest relativistic explosions: GRB 100316D

International Nuclear Information System (INIS)

Margutti, R.; Soderberg, A. M.; Sironi, L.; Zauderer, B. A.; Milisavljevic, D.; Kamble, A.; Wieringa, M. H.; Edwards, P. G.; Chevalier, R. A.; Morsony, B. J.; Duran, R. Barniol; Pian, E.

2013-01-01

We present late-time radio and X-ray observations of the nearby sub-energetic gamma-ray burst (GRB)100316D associated with supernova (SN) 2010bh. Our broad-band analysis constrains the explosion properties of GRB 100316D to be intermediate between highly relativistic, collimated GRBs and the spherical, ordinary hydrogen-stripped SNe. We find that ∼10 49 erg is coupled to mildly relativistic (Γ = 1.5-2), quasi-spherical ejecta, expanding into a medium previously shaped by the progenitor mass-loss with a rate of M-dot ∼ 10 −5 M ⊙ yr −1 (for an assumed wind density profile and wind velocity v w = 1000 km s –1 ). The kinetic energy profile of the ejecta argues for the presence of a central engine and identifies GRB 100316D as one of the weakest central-engine-driven explosions detected to date. Emission from the central engine is responsible for an excess of soft X-ray radiation that dominates over the standard afterglow at late times (t > 10 days). We connect this phenomenology with the birth of the most rapidly rotating magnetars. Alternatively, accretion onto a newly formed black hole might explain the excess of radiation. However, significant departure from the standard fall-back scenario is required.

ARE ULTRA-LONG GAMMA-RAY BURSTS CAUSED BY BLUE SUPERGIANT COLLAPSARS, NEWBORN MAGNETARS, OR WHITE DWARF TIDAL DISRUPTION EVENTS?

Energy Technology Data Exchange (ETDEWEB)

Ioka, Kunihito [Center for Gravitational Physics, Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); Hotokezaka, Kenta; Piran, Tsvi, E-mail: kunihito.ioka@yukawa.kyoto-u.ac.jp [Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel)

2016-12-10

Ultra-long gamma-ray bursts (ulGRBs) are a new population of GRBs with extreme durations of ∼10{sup 4} s. Leading candidates for their origin are blue supergiant collapsars, magnetars, and white dwarf tidal disruption events (WD-TDEs) caused by massive black holes (BHs). Recent observations of supernova-like (SN-like) bumps associated with ulGRBs challenged both the WD-TDE and the blue supergiant models because of the detection of SNe and the absence of hydrogen lines, respectively. We propose that WD-TDEs can accommodate the observed SN-like bumps if the fallback WD matter releases energy into the unbound WD ejecta. The observed ejecta energy, luminosity, and velocity are explained by the gravitational energy, Eddington luminosity, and escape velocity of the formed accretion disk, respectively. We also show that the observed X-rays can ionize the ejecta, eliminating lines. The SN-like light curves (SN 2011kl) for the ulGRB 111209A are consistent with all three models, although a magnetar model is unnatural because the spin-down time required to power the SN-like bump is a hundred times longer than the GRB. Our results imply that TDEs are a possible energy source for SN-like events in general and for ulGRBs in particular.

Tyrosine phosphorylation of Grb14 by Tie2

Directory of Open Access Journals (Sweden)

Dumont Daniel J

2010-10-01

Full Text Available Abstract Background Growth factor receptor bound (Grb proteins 7, 10 and 14 are a family of structurally related multi-domain adaptor proteins involved in a variety of biological processes. Grb7, 10 and 14 are known to become serine and/or threonine phosphorylated in response to growth factor (GF stimulation. Grb7 and 10 have also been shown to become tyrosine phosphorylated under certain conditions. Under experimental conditions Grb7 is tyrosine phosphorylated by the Tie2/Tie-2/Tek angiogenic receptor tyrosine kinase (RTK. Furthermore, Grb14 has also been shown to interact with Tie2, however tyrosine phosphorylation of this Grb family member has yet to be reported. Results Here we report for the first time tyrosine phosphorylation of Grb14. This phosphorylation requires a kinase competent Tie2 as well as intact tyrosines 1100 and 1106 (Y1100 and Y1106 on the receptor. Furthermore, a complete SH2 domain on Grb14 is required for Grb14 tyrosine phosphorylation by Tie2. Grb14 was also able to become tyrosine phosphorylated in primary endothelial cells when treated with a soluble and potent variant of the Tie2 ligand, cartilage oligomeric matrix protein (COMP Ang1. Conclusion Our results show that Grb14, like its family members Grb7 and Grb10, is able to be tyrosine phosphorylated. Furthermore, our data indicate a role for Grb14 in endothelial signaling downstream of the Tie2 receptor.

PROPAGATION OF RELATIVISTIC, HYDRODYNAMIC, INTERMITTENT JETS IN A ROTATING, COLLAPSING GRB PROGENITOR STAR

Energy Technology Data Exchange (ETDEWEB)

Geng, Jin-Jun [School of Astronomy and Space Science, Nanjing University, Nanjing 210046 (China); Zhang, Bing [Department of Physics and Astronomy, University of Nevada Las Vegas, NV 89154 (United States); Kuiper, Rolf, E-mail: gengjinjun@gmail.com, E-mail: zhang@physics.unlv.edu [Institute of Astronomy and Astrophysics, University of Tübingen, Auf der Morgenstelle 10, D-72076 Tübingen (Germany)

2016-12-10

The prompt emission of gamma-ray bursts (GRBs) is characterized by rapid variabilities, which may be a direct reflection of the unsteady central engine. We perform a series of axisymmetric 2.5-dimensional simulations to study the propagation of relativistic, hydrodynamic, intermittent jets through the envelope of a GRB progenitor star. A realistic rapidly rotating star is incorporated as the background of jet propagation, and the star is allowed to collapse due to the gravity of the central black hole. By modeling the intermittent jets with constant-luminosity pulses with equal on and off durations, we investigate how the half period, T , affects the jet dynamics. For relatively small T values (e.g., 0.2 s), the jet breakout time t {sub bo} depends on the opening angle of the jet, with narrower jets more penetrating and reaching the surface at shorter times. For T  ≤ 1 s, the reverse shock (RS) crosses each pulse before the jet penetrates through the stellar envelope. As a result, after the breakout of the first group of pulses at t {sub bo}, several subsequent pulses vanish before penetrating the star, causing a quiescent gap. For larger half periods ( T = 2.0 and 4.0 s), all the pulses can successfully penetrate through the envelope, since each pulse can propagate through the star before the RS crosses the shell. Our results may interpret the existence of a weak precursor in some long GRBs, given that the GRB central engine injects intermittent pulses with a half period T  ≤ 1 s. The observational data seem to be consistent with such a possibility.

First measurement of H I 21 cm emission from a GRB host galaxy indicates a post-merger system

Science.gov (United States)

Arabsalmani, Maryam; Roychowdhury, Sambit; Zwaan, Martin A.; Kanekar, Nissim; Michałowski, Michał J.

2015-11-01

We report the detection and mapping of atomic hydrogen in H I 21 cm emission from ESO 184-G82, the host galaxy of the gamma-ray burst 980425. This is the first instance where H I in emission has been detected from a galaxy hosting a gamma-ray burst (GRB). ESO 184-G82 is an isolated galaxy and contains a Wolf-Rayet region close to the location of the GRB and the associated supernova, SN 1998bw. This is one of the most luminous H II regions identified in the local Universe, with a very high inferred density of star formation. The H I 21 cm observations reveal a high H I mass for the galaxy, twice as large as the stellar mass. The spatial and velocity distribution of the H I 21 cm emission reveals a disturbed rotating gas disc, which suggests that the galaxy has undergone a recent minor merger that disrupted its rotation. We find that the Wolf-Rayet region and the GRB are both located in the highest H I column density region of the galaxy. We speculate that the merger event has resulted in shock compression of the gas, triggering extreme star formation activity, and resulting in the formation of both the Wolf-Rayet region and the GRB. The high H I column density environment of the GRB is consistent with the high H I column densities seen in absorption in the host galaxies of high-redshift GRBs.

Implications of the Early X-Ray Afterglow Light Curves of Swift GRBs

Energy Technology Data Exchange (ETDEWEB)

Granot, Jonathan; /KIPAC, Menlo Park; Konigl, Arieh; /Chicago U., Astron. Astrophys. Ctr. /Chicago U., EFI; Piran, Tsvi; /Hebrew U.

2006-01-17

According to current models, gamma-ray bursts (GRBs) are produced when the energy carried by a relativistic outflow is dissipated and converted into radiation. The efficiency of this process, {epsilon}{sub {gamma}}, is one of the critical factors in any GRB model. The X-ray afterglow light curves of Swift GRBs show an early stage of flattish decay. This has been interpreted as reflecting energy injection. When combined with previous estimates, which have concluded that the kinetic energy of the late ({approx}> 10 hr) afterglow is comparable to the energy emitted in {gamma}-rays, this interpretation implies very high values of {epsilon}{sub {gamma}}, corresponding to {approx}> 90% of the initial energy being converted into {gamma}-rays. Such a high efficiency is hard to reconcile with most models, including in particular the popular internal-shocks model. We re-analyze the derivation of the kinetic energy from the afterglow X-ray flux and re-examine the resulting estimates of the efficiency. We confirm that, if the flattish decay arises from energy injection and the pre-Swift broad-band estimates of the kinetic energy are correct, then {epsilon}{sub {gamma}} {approx}> 0.9. We discuss various issues related to this result, including an alternative interpretation of the light curve in terms of a two-component outflow model, which we apply to the X-ray observations of GRB 050315. We point out, however, that another interpretation of the flattish decay--a variable X-ray afterglow efficiency (e.g., due to a time dependence of afterglow shock microphysical parameters)--is possible. We also show that direct estimates of the kinetic energy from the late X-ray afterglow flux are sensitive to the assumed values of the shock microphysical parameters and suggest that broad-band afterglow fits might have underestimated the kinetic energy (e.g., by overestimating the fraction of electrons that are accelerated to relativistic energies). Either one of these possibilities implies a

GRB 090313 AND THE ORIGIN OF OPTICAL PEAKS IN GAMMA-RAY BURST LIGHT CURVES: IMPLICATIONS FOR LORENTZ FACTORS AND RADIO FLARES

International Nuclear Information System (INIS)

Melandri, A.; Kobayashi, S.; Mundell, C. G.; Guidorzi, C.; Bersier, D.; Steele, I. A.; Smith, R. J.; De Ugarte Postigo, A.; Pooley, G.; Yoshida, M.; Castro-Tirado, A. J.; Gorosabel, J.; Kubanek, P.; Sota, A.; JelInek, M.; Gomboc, A.; Bremer, M.; Winters, J. M.; De Gregorio-Monsalvo, I.; GarcIa-Appadoo, D.

2010-01-01

We use a sample of 19 gamma-ray bursts (GRBs) that exhibit single-peaked optical light curves to test the standard fireball model by investigating the relationship between the time of the onset of the afterglow and the temporal rising index. Our sample includes GRBs and X-ray flashes for which we derive a wide range of initial Lorentz factors (40 e and show that values derived from the early time light-curve properties are consistent with published typical values derived from other afterglow studies. We produce expected radio light curves by predicting the temporal evolution of the expected radio emission from forward and reverse shock components, including synchrotron self-absorption effects at early time. Although a number of GRBs in this sample do not have published radio measurements, we demonstrate the effectiveness of this method in the case of Swift GRB 090313, for which millimetric and centimetric observations were available, and conclude that future detections of reverse-shock radio flares with new radio facilities such as the EVLA and ALMA will test the low-frequency model and provide constraints on magnetic models.

Determination of Cosmological Parameters from GRB Correlation between E_iso (gamma) and Afterglow Flux

Science.gov (United States)

Hannachi, Zitouni; Guessoum, Nidhal; Azzam, Walid

2016-07-01

Context: We use the correlation relations between the energy emitted by the GRBs in their prompt phases and the X-ray afterglow fluxes, in an effort to constrain cosmological parameters and construct a Hubble diagram at high redshifts, i.e. beyond those found in Type Ia supernovae. Methods: We use a sample of 128 Swift GRBs, which we have selected among more than 800 ones observed until July 2015. The selection is based on a few observational constraints: GRB flux higher than 0.4 photons/cm^2/s in the band 15-150 keV; spectrum fitted with simple power law; redshift accurately known and given; and X-ray afterglow observed and flux measured. The statistical method of maximum likelihood is then used to determine the best cosmological parameters (Ω_M, Ω_L) that give the best correlation between the isotropic gamma energies E_{iso} and the afterglow fluxes at the break time t_{b}. The χ^2 statistical test is also used as a way to compare results from two methods. Results & Conclusions: Although the number of GRBs with high redshifts is rather small, and despite the notable dispersion found in the data, the results we have obtained are quite encouraging and promising. The values of the cosmological parameters obtained here are close to those currently used.

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.

FERMI OBSERVATIONS OF GRB 090510: A SHORT-HARD GAMMA-RAY BURST WITH AN ADDITIONAL, HARD POWER-LAW COMPONENT FROM 10 keV TO GeV ENERGIES

International Nuclear Information System (INIS)

Ackermann, M.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Borgland, A. W.; Bouvier, A.; Asano, K.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Bellazzini, R.; Bregeon, J.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; Bhat, P. N.; Bissaldi, E.; Bonamente, E.

2010-01-01

We present detailed observations of the bright short-hard gamma-ray burst GRB 090510 made with the Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) on board the Fermi observatory. GRB 090510 is the first burst detected by the LAT that shows strong evidence for a deviation from a Band spectral fitting function during the prompt emission phase. The time-integrated spectrum is fit by the sum of a Band function with E peak = 3.9 ± 0.3 MeV, which is the highest yet measured, and a hard power-law component with photon index -1.62 ± 0.03 that dominates the emission below ∼20 keV and above ∼100 MeV. The onset of the high-energy spectral component appears to be delayed by ∼0.1 s with respect to the onset of a component well fit with a single Band function. A faint GBM pulse and a LAT photon are detected 0.5 s before the main pulse. During the prompt phase, the LAT detected a photon with energy 30.5 +5.8 -2.6 GeV, the highest ever measured from a short GRB. Observation of this photon sets a minimum bulk outflow Lorentz factor, Γ∼> 1200, using simple γγ opacity arguments for this GRB at redshift z = 0.903 and a variability timescale on the order of tens of ms for the ∼100 keV-few MeV flux. Stricter high confidence estimates imply Γ ∼> 1000 and still require that the outflows powering short GRBs are at least as highly relativistic as those of long-duration GRBs. Implications of the temporal behavior and power-law shape of the additional component on synchrotron/synchrotron self-Compton, external-shock synchrotron, and hadronic models are considered.

THE AFTERGLOW AND ULIRG HOST GALAXY OF THE DARK SHORT GRB 120804A

Energy Technology Data Exchange (ETDEWEB)

Berger, E.; Zauderer, B. A.; Margutti, R.; Laskar, T.; Fong, W.; Chornock, R.; Dupuy, T. J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Levan, A.; Tunnicliffe, R. L. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Mangano, V. [INAF, Istituto di Astrofisica Spaziale e Fisica Cosmica, Via U. La Malfa 153, I-90146 Palermo (Italy); Fox, D. B. [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Tanvir, N. R. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Menten, K. M. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany); Hjorth, J. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen O (Denmark); Roth, K. [Gemini Observatory, 670 North Aohoku Place, Hilo, HI 96720 (United States)

2013-03-10

galaxies in the short GRB host sample is {approx}0.01 and {approx}0.25 (for pure stellar mass and star formation weighting, respectively). Thus, the observed fraction of two events in about 25 hosts (GRBs 120804A and 100206A) appears to support our previous conclusion that short GRBs track both stellar mass and star formation activity.

The History and Legacy of BATSE

Science.gov (United States)

Fishman, Gerald J.

2012-01-01

The BATSE experiment on the Compton Gamma-ray Observatory was the first large detector system specifically designed for the study of gamma-ray bursts. The eight large-area detectors allowed full-sky coverage and were optimized to operate in the energy region of the peak emission of most GRBs. BATSE provided detailed observations of the temporal and spectral characteristics of large samples of GRBs, and it was the first experiment to provide rapid notifications of the coarse location of many them. It also provided strong evidence for the cosmological distances to GRBs through the observation of the sky distribution and intensity distribution of numerous GRBs. The large number of GRBs observed with the high- sensitivity BATSE detectors continues to provide a database of GRB spectral and temporal properties in the primary energy range of GRB emission that will likely not be exceeded for at least another decade. The origin and development of the BATSE experiment, some highlights from the mission and its continuing legacy are described in this paper.

An enigmatic long-lasting gamma-ray burst not accompanied by a bright supernova.

Science.gov (United States)

Della Valle, M; Chincarini, G; Panagia, N; Tagliaferri, G; Malesani, D; Testa, V; Fugazza, D; Campana, S; Covino, S; Mangano, V; Antonelli, L A; D'Avanzo, P; Hurley, K; Mirabel, I F; Pellizza, L J; Piranomonte, S; Stella, L

2006-12-21

Gamma-ray bursts (GRBs) are short, intense flashes of soft gamma-rays coming from the distant Universe. Long-duration GRBs (those lasting more than approximately 2 s) are believed to originate from the deaths of massive stars, mainly on the basis of a handful of solid associations between GRBs and supernovae. GRB 060614, one of the closest GRBs discovered, consisted of a 5-s hard spike followed by softer, brighter emission that lasted for approximately 100 s (refs 8, 9). Here we report deep optical observations of GRB 060614 showing no emerging supernova with absolute visual magnitude brighter than M(V) = -13.7. Any supernova associated with GRB 060614 was therefore at least 100 times fainter, at optical wavelengths, than the other supernovae associated with GRBs. This demonstrates that some long-lasting GRBs can either be associated with a very faint supernova or produced by different phenomena.

ASTROBIOLOGICAL EFFECTS OF GAMMA-RAY BURSTS IN THE MILKY WAY GALAXY

Energy Technology Data Exchange (ETDEWEB)

Gowanlock, Michael G., E-mail: gowanloc@mit.edu [Massachusetts Institute of Technology, Haystack Observatory, 99 Millstone Road, Westford, MA 01886 (United States)

2016-11-20

A planet having protective ozone within the collimated beam of a gamma-ray burst (GRB) may suffer ozone depletion, potentially causing a mass extinction event to existing life on a planet’s surface and oceans. We model the dangers of long GRBs to planets in the Milky Way and utilize a static statistical model of the Galaxy, which matches major observable properties, such as the inside-out star formation history (SFH), metallicity evolution, and three-dimensional stellar number density distribution. The GRB formation rate is a function of both the SFH and metallicity. However, the extent to which chemical evolution reduces the GRB rate over time in the Milky Way is still an open question. Therefore, we compare the damaging effects of GRBs to biospheres in the Milky Way using two models. One model generates GRBs as a function of the inside-out SFH. The other model follows the SFH, but generates GRB progenitors as a function of metallicity, thereby favoring metal-poor host regions of the Galaxy over time. If the GRB rate only follows the SFH, the majority of the GRBs occur in the inner Galaxy. However, if GRB progenitors are constrained to low-metallicity environments, then GRBs only form in the metal-poor outskirts at recent epochs. Interestingly, over the past 1 Gyr, the surface density of stars (and their corresponding planets), which survive a GRB is still greatest in the inner galaxy in both models. The present-day danger of long GRBs to life at the solar radius ( R {sub ⊙} = 8 kpc) is low. We find that at least ∼65% of stars survive a GRB over the past 1 Gyr. Furthermore, when the GRB rate was expected to have been enhanced at higher redshifts, such as z ≳ 0.5, our results suggest that a large fraction of planets would have survived these lethal GRB events.

THE SECOND SWIFT BURST ALERT TELESCOPE GAMMA-RAY BURST CATALOG

International Nuclear Information System (INIS)

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

2011-01-01

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 T 90 and T 50 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 obs peak 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 T 90 and the observed spectra with redshifts. The T 90

The latest two GRB detected by Hete-2: GRB 051022 and GRB 051028

International Nuclear Information System (INIS)

Castro-Tirado, A. J.; Jelinek, M.; Pandey, S. B.; Ugarte Postigo, A. de; Gorosabel, J.; McBreen, S.; Bremer, M.; Guziy, S.; Bihain, G.; Caballero, J. A.; Ferrero, P.; Jong, J de; Misra, K.; Sahu, D. K.

2006-01-01

We present multiwavelength observations of the latest two GRB detected by Hete-2 in 2005. For GRB 051022, no optical/nIR afterglow has been detected, in spite of the strong gamma-ray emission and the reported X-ray afterglow discovered by Swift. A mm afterglow was discovered at PdB confirming the association of this event with a luminous (MV = - 21.5) galaxy within the X-ray error box. Spectroscopy of this galaxy shows strong a strong [O II] emission line at z = 0.807, besides weaker [O III] emission. The X-ray spectrum showed evidence of considerable absorption by neutral gas with NH,X-ray = 4.5 x 1022 cm2 (at rest frame). ISM absorption by dust in the host galaxy at z = 0.807 cannot certainly account for the non-detection of the optical afterglow, unless the dust-to-gas ratio is quite different than that seen in our Galaxy. It is possible then that GRB 051022 was produced in an obscured, stellar forming region in its parent host galaxy.For GRB 051028, the data can be interpreted by collimated emission (a jet model with p = 2.4) moving in an homogeneous ISM and with a cooling frequency vc still above the X-rays at 0.5 days after the burst onset. GRB 051028 can be classified as a 'gray' or 'potentially dark' GRB. The Swift/XRT data are consistent with the interpretation that the reason for the optical dimness is not extra absorption in the host galaxy, but rather the GRB taking place at high-redshift

Canonical correlation between the gamma and X-ray data of Swift GRBs

International Nuclear Information System (INIS)

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

2009-01-01

We used the canonical correlation analysis of the multivariate statistics to study the interrelation between the gamma (Fluence, 1 sec Peakflux, duration) and X-ray (early X flux, 24 hours X flux, X decay index, X spectral index, X HI column density) data. We computed the canonical correlations and variables showing that there is a significant interrelation between the gamma and X-ray data. Using the canonical variables resulted in the analysis we computed their correlations (canonical loadings) with the original ones. The canonical loadings revealed that the gamma-ray fluence and the early X-ray flux give the strongest contribution to the correlation in contrast to the X-ray decay index and spectral index. An interesting new result appears to be the strong contribution of the HI column density to the correlation. Accepting the collapsar model of long GRBs this effect may be interpreted as an indication for the ejection of an HI envelope by the progenitor in the course of producing the GRB.

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.;

SN 2010ay IS A LUMINOUS AND BROAD-LINED TYPE Ic SUPERNOVA WITHIN A LOW-METALLICITY HOST GALAXY

Energy Technology Data Exchange (ETDEWEB)

Sanders, N. E.; Soderberg, A. M.; Foley, R. J.; Chornock, R.; Chomiuk, L.; Berger, E. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Valenti, S.; Smartt, S.; Botticella, M. T. [Astrophysics Research Centre, School of Maths and Physics, Queen' s University, Belfast BT7 1NN (United Kingdom); Hurley, K. [Space Sciences Laboratory, University of California Berkeley, 7 Gauss Way, Berkeley, CA 94720 (United States); Barthelmy, S. D.; Gehrels, N.; Cline, T. [NASA Goddard Space Flight Center, Code 661, Greenbelt, MD 20771 (United States); Levesque, E. M. [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Narayan, G. [Department of Physics, Harvard University, Cambridge, MA 02138 (United States); Briggs, M. S.; Connaughton, V. [CSPAR, University of Alabama in Huntsville, Huntsville, AL (United States); Terada, Y. [Department of Physics, Saitama University, Shimo-Okubo, Sakura-ku, Saitama-shi, Saitama 338-8570 (Japan); Golenetskii, S.; Mazets, E., E-mail: nsanders@cfa.harvard.edu [Ioffe Physico-Technical Institute, Laboratory for Experimental Astrophysics, 26 Polytekhnicheskaya, St. Petersburg 194021 (Russian Federation); and others

2012-09-10

We report on our serendipitous pre-discovery detection and follow-up observations of the broad-lined Type Ic supernova (SN Ic) 2010ay at z = 0.067 imaged by the Pan-STARRS1 3{pi} survey just {approx}4 days after explosion. The supernova (SN) had a peak luminosity, M{sub R} Almost-Equal-To -20.2 mag, significantly more luminous than known GRB-SNe and one of the most luminous SNe Ib/c ever discovered. The absorption velocity of SN 2010ay is v{sub Si} Almost-Equal-To 19 Multiplication-Sign 10{sup 3} km s{sup -1} at {approx}40 days after explosion, 2-5 times higher than other broad-lined SNe and similar to the GRB-SN 2010bh at comparable epochs. Moreover, the velocity declines {approx}2 times slower than other SNe Ic-BL and GRB-SNe. Assuming that the optical emission is powered by radioactive decay, the peak magnitude implies the synthesis of an unusually large mass of {sup 56}Ni, M{sub Ni} = 0.9 M{sub Sun }. Applying scaling relations to the light curve, we estimate a total ejecta mass, M{sub ej} Almost-Equal-To 4.7 M{sub Sun }, and total kinetic energy, E{sub K} Almost-Equal-To 11 Multiplication-Sign 10{sup 51} erg. The ratio of M{sub Ni} to M{sub ej} is {approx}2 times as large for SN 2010ay as typical GRB-SNe and may suggest an additional energy reservoir. The metallicity (log (O/H){sub PP04} + 12 = 8.19) of the explosion site within the host galaxy places SN 2010ay in the low-metallicity regime populated by GRB-SNe, and {approx}0.5(0.2) dex lower than that typically measured for the host environments of normal (broad-lined) SNe Ic. We constrain any gamma-ray emission with E{sub {gamma}} {approx}< 6 Multiplication-Sign 10{sup 48} erg (25-150 keV), and our deep radio follow-up observations with the Expanded Very Large Array rule out relativistic ejecta with energy E {approx}> 10{sup 48} erg. We therefore rule out the association of a relativistic outflow like those that accompanied SN 1998bw and traditional long-duration gamma-ray bursts (GRBs), but we place less

The Second Swift BAT Gamma-Ray Burst Catalog

Science.gov (United States)

Barthelmy, S. D.; Baumgartner, W. H.; Cummings, J. R.; Fenimore, E. E.; Gehrels, N.; Krimm, H. A.; Markwardt, C. B.; Palmer, D. M.; Parsons, A. M.; Sato, G.;

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.

A peculiar low-luminosity short gamma-ray burst from a double neutron star merger progenitor.

Science.gov (United States)

Zhang, B-B; Zhang, B; Sun, H; Lei, W-H; Gao, H; Li, Y; Shao, L; Zhao, Y; Hu, Y-D; Lü, H-J; Wu, X-F; Fan, X-L; Wang, G; Castro-Tirado, A J; Zhang, S; Yu, B-Y; Cao, Y-Y; Liang, E-W

2018-01-31

Double neutron star (DNS) merger events are promising candidates of short gamma-ray burst (sGRB) progenitors as well as high-frequency gravitational wave (GW) emitters. On August 17, 2017, such a coinciding event was detected by both the LIGO-Virgo gravitational wave detector network as GW170817 and Gamma-Ray Monitor on board NASA's Fermi Space Telescope as GRB 170817A. Here, we show that the fluence and spectral peak energy of this sGRB fall into the lower portion of the distributions of known sGRBs. Its peak isotropic luminosity is abnormally low. The estimated event rate density above this luminosity is at least [Formula: see text] Gpc -3  yr -1 , which is close to but still below the DNS merger event rate density. This event likely originates from a structured jet viewed from a large viewing angle. There are similar faint soft GRBs in the Fermi archival data, a small fraction of which might belong to this new population of nearby, low-luminosity sGRBs.

The Ultra-long GRB 111209A. II. Prompt to Afterglow and Afterglow Properties

Science.gov (United States)

Stratta, G.; Gendre, B.; Atteia, J. L.; Boër, M.; Coward, D. M.; De Pasquale, M.; Howell, E.; Klotz, A.; Oates, S.; Piro, L.

2013-12-01

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.

Ten per cent polarized optical emission from GRB 090102.

Science.gov (United States)

Steele, I A; Mundell, C G; Smith, R J; Kobayashi, S; Guidorzi, C

2009-12-10

The nature of the jets and the role of magnetic fields in gamma-ray bursts (GRBs) remains unclear. In a baryon-dominated jet only weak, tangled fields generated in situ through shocks would be present. In an alternative model, jets are threaded with large-scale magnetic fields that originate at the central engine and that accelerate and collimate the material. To distinguish between the models the degree of polarization in early-time emission must be measured; however, previous claims of gamma-ray polarization have been controversial. Here we report that the early optical emission from GRB 090102 was polarized at 10 +/- 1 per cent, indicating the presence of large-scale fields originating in the expanding fireball. If the degree of polarization and its position angle were variable on timescales shorter than our 60-second exposure, then the peak polarization may have been larger than ten per cent.

A NEW CLASSIFICATION METHOD FOR GAMMA-RAY BURSTS

International Nuclear Information System (INIS)

Lue Houjun; Liang Enwei; Zhang Binbin; Zhang Bing

2010-01-01

Recent Swift observations suggest that the traditional long versus short gamma-ray burst (GRB) classification scheme does not always associate GRBs to the two physically motivated model types, i.e., Type II (massive star origin) versus Type I (compact star origin). We propose a new phenomenological classification method of GRBs by introducing a new parameter ε = E γ,iso,52 /E 5/3 p,z,2 , where E γ,iso is the isotropic gamma-ray energy (in units of 10 52 erg) and E p,z is the cosmic rest-frame spectral peak energy (in units of 100 keV). For those short GRBs with 'extended emission', both quantities are defined for the short/hard spike only. With the current complete sample of GRBs with redshift and E p measurements, the ε parameter shows a clear bimodal distribution with a separation at ε ∼ 0.03. The high-ε region encloses the typical long GRBs with high luminosity, some high-z 'rest-frame-short' GRBs (such as GRB 090423 and GRB 080913), as well as some high-z short GRBs (such as GRB 090426). All these GRBs have been claimed to be of Type II origin based on other observational properties in the literature. All the GRBs that are argued to be of Type I origin are found to be clustered in the low-ε region. They can be separated from some nearby low-luminosity long GRBs (in 3σ) by an additional T 90 criterion, i.e., T 90,z ∼< 5 s in the Swift/BAT band. We suggest that this new classification scheme can better match the physically motivated Type II/I classification scheme.

PHOTOSPHERE EMISSION FROM A HYBRID RELATIVISTIC OUTFLOW WITH ARBITRARY DIMENSIONLESS ENTROPY AND MAGNETIZATION IN GRBs

Energy Technology Data Exchange (ETDEWEB)

Gao, He [Current address: Department of Astronomy and Astrophysics, Department of Physics, Center for Particle Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Zhang, Bing, E-mail: gaohe@physics.unlv.edu, E-mail: zhang@physics.unlv.edu, E-mail: hug18@psu.edu [Department of Physics and Astronomy, University of Nevada, Las Vegas, NV 89154 (United States)

2015-03-10

In view of the recent Fermi observations of gamma-ray burst (GRB) prompt emission spectra, we develop a theory of photosphere emission of a hybrid relativistic outflow with a hot fireball component (defined by dimensionless entropy η) and a cold Poynting-flux component (defined by magnetization σ{sub 0} at the central engine). We consider the scenarios both without and with sub-photospheric magnetic dissipations. Based on a simplified toy model of jet dynamics, we develop two approaches: a 'bottom-up' approach to predict the temperature (for a non-dissipative photosphere) and luminosity of the photosphere emission and its relative brightness for a given pair of (η, σ{sub 0}); and a 'top-down' approach to diagnose central engine parameters (η and σ{sub 0}) based on the observed quasi-thermal photosphere emission properties. We show that a variety of observed GRB prompt emission spectra with different degrees of photosphere thermal emission can be reproduced by varying η and σ{sub 0} within the non-dissipative photosphere scenario. In order to reproduce the observed spectra, the outflows of most GRBs need to have a significant σ, both at the central engine and at the photosphere. The σ value at 10{sup 15} cm from the central engine (a possible non-thermal emission site) is usually also greater than unity, so that internal-collision-induced magnetic reconnection and turbulence (ICMART) may be the mechanism to power the non-thermal emission. We apply our top-down approach to GRB 110721A and find that the temporal evolution behavior of its blackbody component can be well interpreted with a time-varying (η, σ{sub 0}) at the central engine, instead of invoking a varying engine base size r {sub 0} as proposed by previous authors.

A NEW CLASS OF GAMMA-RAY BURSTS FROM STELLAR DISRUPTIONS BY INTERMEDIATE-MASS BLACK HOLES

International Nuclear Information System (INIS)

Gao, H.; Lu, Y.; Zhang, S. N.

2010-01-01

It has been argued that the long gamma-ray burst (GRB) of GRB 060614 without an associated supernova (SN) has challenged the current classification and fuel model for long GRBs, and thus a tidal disruption model has been proposed to account for such an event. Since it is difficult to detect SNe for long GRBs at high redshift, the absence of an SN association cannot be regarded as the solid criterion for a new classification of long GRBs similar to GRB 060614, called GRB 060614-type bursts. Fortunately, we now know that there is an obvious periodic substructure observed in the prompt light curve of GRB 060614. We thus use such periodic substructure as a potential criterion to categorize some long GRBs into a new class of bursts, which might have been fueled by an intermediate-mass black hole (IMBH) gulping a star, rather than a massive star collapsing to form a black hole. Therefore, the second criterion to recognize for this new class of bursts is whether they fit the tidal disruption model. From a total of 328 Swift GRBs with accurately measured durations and without SN association, we find 25 GRBs satisfying the criteria for GRB 060614-type bursts: seven of them are with known redshifts and 18 with unknown redshifts. These new bursts are ∼6% of the total Swift GRBs, which are clustered into two subclasses: Type I and Type II with considerably different viscous parameters of accretion disks formed by tidally disrupting their different progenitor stars. We suggest that the two different kinds of progenitors are solar-type stars and white dwarfs: the progenitors for four Type I bursts with viscous parameter of around 0.1 are solar-type stars, and the progenitors for 21 Type II bursts with viscous parameter of around 0.3 are white dwarfs. The potential applications of this new class of GRBs as cosmic standard candles are discussed briefly.

GRB 080916C AND GRB 090510: THE HIGH-ENERGY EMISSION AND THE AFTERGLOW

International Nuclear Information System (INIS)

Gao Weihong; Mao Jirong; Xu Dong; Fan Yizhong

2009-01-01

We constrain the physical composition of the outflows of GRBs 080916C and 090510 with the prompt emission data and find that the former is likely magnetic, while the latter may be baryonic. The X-ray and optical afterglow emission of both GRBs can be reasonably fitted using the standard external shock model but the density profiles of the circum-burst medium are different. We also propose a simple method to estimate the number of seed photons supposing the GeV afterglow photons are due to the inverse Compton radiation of external forward shock electrons. The seed photons needed in the modeling are too many to be realistic for both events. The synchrotron radiation of the forward shock seems able to account for the GeV afterglow data.

OBSERVATIONAL SEARCH FOR PeV-EeV TAU NEUTRINO FROM GRB081203A

International Nuclear Information System (INIS)

Aita, Y.; Aoki, T.; Asaoka, Y.; Chonan, T.; Jobashi, M.; Masuda, M.; Morimoto, Y.; Noda, K.; Sasaki, M.; Asoh, J.; Ishikawa, N.; Ogawa, S.; Learned, J. G.; Matsuno, S.; Olsen, S.; Binder, P.-M.; Hamilton, J.; Sugiyama, N.; Watanabe, Y.

2011-01-01

We report the first observational search for tau neutrinos (ν τ ) from gamma-ray bursts (GRBs) using one of the Ashra light collectors. The Earth-skimming ν τ technique of imaging Cherenkov τ showers was applied as a detection method. We set stringent upper limits on the ν τ fluence in PeV-EeV region for 3780 s (between 2.83 and 1.78 hr before) and another 3780 s (between 21.2 and 22.2 hr after) surrounding GRB081203A triggered by the Swift satellite. This first search for PeV-EeV ν τ complements other experiments in energy range and methodology, and suggests the prologue of 'multi-particle astronomy' with a precise determination of time and location.

Swift captures the spectrally evolving prompt emission of GRB070616

Science.gov (United States)

Starling, R. L. C.; O'Brien, P. T.; Willingale, R.; Page, K. L.; Osborne, J. P.; de Pasquale, M.; Nakagawa, Y. E.; Kuin, N. P. M.; Onda, K.; Norris, J. P.; Ukwatta, T. N.; Kodaka, N.; Burrows, D. N.; Kennea, J. A.; Page, M. J.; Perri, M.; Markwardt, C. B.

2008-02-01

The origins of gamma-ray burst (GRB) prompt emission are currently not well understood and in this context long, well-observed events are particularly important to study. We present the case of GRB070616, analysing the exceptionally long-duration multipeaked prompt emission, and later afterglow, captured by all the instruments on-board Swift and by Suzaku Wide-Band All-Sky Monitor (WAM). The high-energy light curve remained generally flat for several hundred seconds before going into a steep decline. Spectral evolution from hard to soft is clearly taking place throughout the prompt emission, beginning at 285s after the trigger and extending to 1200s. We track the movement of the spectral peak energy, whilst observing a softening of the low-energy spectral slope. The steep decline in flux may be caused by a combination of this strong spectral evolution and the curvature effect. We investigate origins for the spectral evolution, ruling out a superposition of two power laws and considering instead an additional component dominant during the late prompt emission. We also discuss origins for the early optical emission and the physics of the afterglow. The case of GRB070616 clearly demonstrates that both broad-band coverage and good time resolution are crucial to pin down the origins of the complex prompt emission in GRBs. This paper is dedicated to the memory of Dr Francesca Tamburelli who died during its production. Francesca played a fundamental role within the team which is in charge of the development of the Swift X-Ray Telescope (XRT) data analysis software at the Italian Space Agency's Science Data Centre in Frascati. She is sadly missed. E-mail: rlcs1@star.le.ac.uk

DETECTION OF GAMMA-RAY POLARIZATION IN PROMPT EMISSION OF GRB 100826A

Energy Technology Data Exchange (ETDEWEB)

Yonetoku, Daisuke; Murakami, Toshio; Sakashita, Tomonori; Morihara, Yoshiyuki; Takahashi, Takuya; Fujimoto, Hirofumi; Kodama, Yoshiki [College of Science and Engineering, School of Mathematics and Physics, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192 (Japan); Gunji, Shuichi; Toukairin, Noriyuki [Department of Physics, Faculty of Science, Yamagata University, 1-4-12, Koshirakawa, Yamagata, Yamagata 990-8560 (Japan); Mihara, Tatehiro [Cosmic Radiation Laboratory, RIKEN, 2-1, Hirosawa, Wako City, Saitama 351-0198 (Japan); Toma, Kenji [Department of Earth and Space Science, Osaka University, Toyonaka 560-0043 (Japan); Kubo, Shin, E-mail: yonetoku@astro.s.kanazawa-u.ac.jp [Clear Pulse Co. Ltd., 6-25-17, Chuo, Ohta-ku, Tokyo 143-0024 (Japan); Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1, Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan)

2011-12-20

We report the polarization measurement in prompt {gamma}-ray emission of GRB 100826A with the Gamma-Ray Burst Polarimeter on board the small solar-power-sail demonstrator IKAROS. We detected the firm change of polarization angle (PA) during the prompt emission with 99.9% (3.5{sigma}) confidence level, and the average polarization degree ({Pi}) of 27% {+-} 11% with 99.4% (2.9{sigma}) confidence level. Here the quoted errors are given at 1{sigma} confidence level for the two parameters of interest. The systematic errors have been carefully included in this analysis, unlike other previous reports. Such a high {Pi} can be obtained in several emission models of gamma-ray bursts (GRBs), including synchrotron and photospheric models. However, it is difficult to explain the observed significant change of PA within the framework of axisymmetric jet as considered in many theoretical works. The non-axisymmetric (e.g., patchy) structures of the magnetic fields and/or brightness inside the relativistic jet are therefore required within the observable angular scale of {approx}{Gamma}{sup -1}. Our observation strongly indicates that the polarization measurement is a powerful tool to constrain the GRB production mechanism, and more theoretical works are needed to discuss the data in more detail.

ARE ULTRA-LONG GAMMA-RAY BURSTS DIFFERENT?

Energy Technology Data Exchange (ETDEWEB)

Boër, M.; Gendre, B. [CNRS-ARTEMIS, Boulevard de l' Observatoire, CS 34229, 06304 Nice Cedex 4 (France); Stratta, G., E-mail: michel.boer@unice.fr [Università degli Studi di Urbino Carlo Bo, I-61029 Urbino (Italy)

2015-02-10

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.

A GRB and Broad-lined Type Ic Supernova from a Single Central Engine

Science.gov (United States)

Barnes, Jennifer; Duffell, Paul C.; Liu, Yuqian; Modjaz, Maryam; Bianco, Federica B.; Kasen, Daniel; MacFadyen, Andrew I.

2018-06-01

Unusually high velocities (≳0.1c) and correspondingly high kinetic energies have been observed in a subset of Type Ic supernovae (so-called “broad-lined Ic” supernovae; SNe Ic-BL), prompting a search for a central engine model capable of generating such energetic explosions. A clue to the explosion mechanism may lie in the fact that all supernovae that accompany long-duration gamma-ray bursts (GRBs) belong to the SN Ic-BL class. Using a combination of two-dimensional relativistic hydrodynamics and radiation transport calculations, we demonstrate that the central engine responsible for long GRBs can also trigger an SN Ic-BL. We find that a reasonable GRB engine injected into a stripped Wolf–Rayet progenitor produces a relativistic jet with energy ∼1051 erg, as well as an SN whose synthetic light curves and spectra are fully consistent with observed SNe Ic-BL during the photospheric phase. As a result of the jet’s asymmetric energy injection, the SN spectra and light curves depend on viewing angle. The impact of viewing angle on the spectrum is particularly pronounced at early times, while the viewing-angle dependence for the light curves (∼10% variation in bolometric luminosity) persists throughout the photospheric phase.

The GRB-SLSN connection: misaligned magnetars, weak jet emergence, and observational signatures

Science.gov (United States)

Margalit, Ben; Metzger, Brian D.; Thompson, Todd A.; Nicholl, Matt; Sukhbold, Tuguldur

2018-04-01

Multiple lines of evidence support a connection between hydrogen-poor superluminous supernovae (SLSNe) and long-duration gamma-ray bursts (GRBs). Both classes of events require a powerful central energy source, usually attributed to a millisecond magnetar or an accreting black hole. The GRB-SLSN link raises several theoretical questions: What distinguishes the engines responsible for these different phenomena? Can a single engine power both a GRB and a luminous SN in the same event? We propose a unifying model for magnetar thermalization and jet formation: misalignment between the rotation (Ω) and magnetic dipole (μ) axes dissipates a fraction of the spin-down power by reconnection in the striped equatorial wind, providing a guaranteed source of `thermal' emission to power the supernova. The remaining unthermalized power energizes a relativistic jet. We show that even weak relativistic jets of luminosity ˜1046 erg s-1 can escape the expanding SN ejecta implying that escaping relativistic jets may accompany many SLSNe. We calculate the observational signature of these jets. We show that they may produce transient ultraviolet (UV) cocoon emission lasting a few hours when the jet breaks out of the ejecta surface. A longer lived optical/UV signal may originate from a mildly relativistic wind driven from the interface between the jet and the ejecta walls, which could explain the secondary early-time maximum observed in some SLSNe light curves, such as LSQ14bdq. Our scenario predicts a population of GRB from on-axis jets with extremely long durations, potentially similar to the population of `jetted-tidal disruption events', in coincidence with a small subset of SLSNe.

A Neutron Star Binary Merger Model for GW170817/GRB 170817A/SSS17a

Energy Technology Data Exchange (ETDEWEB)

Murguia-Berthier, A.; Ramirez-Ruiz, E.; Kilpatrick, C. D.; Foley, R. J.; Coulter, D. A.; Pan, Y.-C.; Prochaska, J. X.; Rojas-Bravo, C.; Siebert, M. R. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Kasen, D. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Lee, W. H. [Instituto de Astronomía, Universidad Nacional Autónoma de México, Circuito Exterior, C.U., A. Postal 70-264, 04510 Cd. de México, México (Mexico); Piro, A. L.; Drout, M. R.; Madore, B. F.; Shappee, B. J.; Simon, J. D. [The Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Rest, A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

2017-10-20

The merging neutron star gravitational-wave event GW170817 has been observed throughout the entire electromagnetic spectrum from radio waves to γ -rays. The resulting energetics, variability, and light curves are shown to be consistent with GW170817 originating from the merger of two neutron stars, in all likelihood followed by the prompt gravitational collapse of the massive remnant. The available γ -ray, X-ray, and radio data provide a clear probe for the nature of the relativistic ejecta and the non-thermal processes occurring within, while the ultraviolet, optical, and infrared emission are shown to probe material torn during the merger and subsequently heated by the decay of freshly synthesized r -process material. The simplest hypothesis, that the non-thermal emission is due to a low-luminosity short γ -ray burst (sGRB), seems to agree with the present data. While low-luminosity sGRBs might be common, we show here that the collective prompt and multi-wavelength observations are also consistent with a typical, powerful sGRB seen off-axis. Detailed follow-up observations are thus essential before we can place stringent constraints on the nature of the relativistic ejecta in GW170817.

Marginally fast cooling synchrotron models for prompt GRBs

Science.gov (United States)

Beniamini, Paz; Barniol Duran, Rodolfo; Giannios, Dimitrios

2018-05-01

Previous studies have considered synchrotron as the emission mechanism for prompt gamma-ray bursts (GRBs). These works have shown that the electrons must cool on a time-scale comparable to the dynamic time at the source in order to satisfy spectral constraints while maintaining high radiative efficiency. We focus on conditions where synchrotron cooling is balanced by a continuous source of heating, and in which these constraints are naturally satisfied. Assuming that a majority of the electrons in the emitting region are contributing to the observed peak, we find that the energy per electron has to be E ≳ 20 GeV and that the Lorentz factor of the emitting material has to be very large 103 ≲ Γem ≲ 104, well in excess of the bulk Lorentz factor of the jet inferred from GRB afterglows. A number of independent constraints then indicate that the emitters must be moving relativistically, with Γ΄ ≈ 10, relative to the bulk frame of the jet and that the jet must be highly magnetized upstream of the emission region, σup ≳ 30. The emission radius is also strongly constrained in this model to R ≳ 1016 cm. These values are consistent with magnetic jet models where the dissipation is driven by magnetic reconnection that takes place far away from the base of the jet.

The bright optical afterglow of the nearby gamma-ray burst of 29 March 2003.

Science.gov (United States)

Price, P A; Fox, D W; Kulkarni, S R; Peterson, B A; Schmidt, B P; Soderberg, A M; Yost, S A; Berger, E; Djorgovski, S G; Frail, D A; Harrison, F A; Sari, R; Blain, A W; Chapman, S C

2003-06-19

Past studies of cosmological gamma-ray bursts (GRBs) have been hampered by their extreme distances, resulting in faint afterglows. A nearby GRB could potentially shed much light on the origin of these events, but GRBs with a redshift z burst of 29 March 2003 (GRB030329; ref. 2). The brightness of the afterglow and the prompt report of its position resulted in extensive follow-up observations at many wavelengths, along with the measurement of the redshift, z = 0.169 (ref. 4). The gamma-ray and afterglow properties of GRB030329 are similar to those of GRBs at cosmological redshifts. Observations have already identified the progenitor as a massive star that exploded as a supernova.

THE BLACK HOLE CENTRAL ENGINE FOR ULTRA-LONG GAMMA-RAY BURST 111209A AND ITS ASSOCIATED SUPERNOVA 2011KL

Energy Technology Data Exchange (ETDEWEB)

Gao, He; You, Zhi-Qiang [Department of Astronomy, Beijing Normal University, Beijing 100875 (China); Lei, Wei-Hua; Xie, Wei, E-mail: gaohe@bnu.edu.cn, E-mail: leiwh@hust.edu.cn [School of Physics, Huazhong University of Science and Technology, Wuhan, 430074 (China)

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.

The HEASARC Swift Gamma-Ray Burst Archive: The Pipeline and the Catalog

Science.gov (United States)

Donato, Davide; Angelini, Lorella; Padgett, C.A.; Reichard, T.; Gehrels, Neil; Marshall, Francis E.; Sakamoto, Takanori

2012-01-01

Since its launch in late 2004, the Swift satellite triggered or observed an average of one gamma-ray burst (GRB) every 3 days, for a total of 771 GRBs by 2012 January. Here, we report the development of a pipeline that semi automatically performs the data-reduction and data-analysis processes for the three instruments on board Swift (BAT, XRT, UVOT). The pipeline is written in Perl, and it uses only HEAsoft tools and can be used to perform the analysis of a majority of the point-like objects (e.g., GRBs, active galactic nuclei, pulsars) observed by Swift. We run the pipeline on the GRBs, and we present a database containing the screened data, the output products, and the results of our ongoing analysis. Furthermore, we created a catalog summarizing some GRB information, collected either by running the pipeline or from the literature. The Perl script, the database, and the catalog are available for downloading and querying at the HEASARC Web site.

The threat to life from Eta Carinae and gamma ray bursts

CERN Document Server

Dar, Arnon; Dar, Arnon

2001-01-01

Eta Carinae, the most massive and luminous star known in our galaxy, is rapidly boiling matter off its surface. At any time its core could collapse into a black hole, which may result in a gamma-ray burst (GRB) that can devastate life on Earth. Auspiciously, recent observations indicate that the GRBs are narrowly beamed in cones along the rotational axis of the progenitor star. In the case of Eta Carinae the GRBs will not point to us, but will be ravaging to life on planets in our galaxy that happen to lie within the two beaming cones. The mean rate of massive life extinctions by jets from GRBs, per life-supporting planet in galaxies like ours, is once in 100 million years, comparable to the rate of major extinctions observed in the geological records of our planet. GRB extinctions also provide an answer to Fermi's question about alien visitors: ``Where are they?''

THE SWIFT GRB HOST GALAXY LEGACY SURVEY. II. REST-FRAME NEAR-IR LUMINOSITY DISTRIBUTION AND EVIDENCE FOR A NEAR-SOLAR METALLICITY THRESHOLD

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); Tanvir, N. R. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH (United Kingdom); Hjorth, J.; Fynbo, J. P. U.; Krühler, T. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 København Ø (Denmark); Laskar, T.; Berger, E. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Chary, R. [US Planck Data Center, MS220-6, Pasadena, CA 91125 (United States); Postigo, A. de Ugarte [Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, E-18008, Granada (Spain); Levan, A. J. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Michałowski, M. J. [Scottish Universities Physics Alliance, Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh, EH9 3HJ (United Kingdom); Schulze, S., E-mail: dperley@dark-cosmology.dk [Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, 7820436 Macul, Santiago 22 (Chile)

2016-01-20

We present rest-frame near-IR (NIR) luminosities and stellar masses for a large and uniformly selected population of gamma-ray burst (GRB) host galaxies using deep Spitzer Space Telescope imaging of 119 targets from the Swift GRB Host Galaxy Legacy Survey spanning 0.03 < z < 6.3, and we determine the effects of galaxy evolution and chemical enrichment on the mass distribution of the GRB host population across cosmic history. We find a rapid increase in the characteristic NIR host luminosity between z ∼ 0.5 and z ∼ 1.5, but little variation between z ∼ 1.5 and z ∼ 5. Dust-obscured GRBs dominate the massive host population but are only rarely seen associated with low-mass hosts, indicating that massive star-forming galaxies are universally and (to some extent) homogeneously dusty at high redshift while low-mass star-forming galaxies retain little dust in their interstellar medium. Comparing our luminosity distributions with field surveys and measurements of the high-z mass–metallicity relation, our results have good consistency with a model in which the GRB rate per unit star formation is constant in galaxies with gas-phase metallicity below approximately the solar value but heavily suppressed in more metal-rich environments. This model also naturally explains the previously reported “excess” in the GRB rate beyond z ≳ 2; metals stifle GRB production in most galaxies at z < 1.5 but have only minor impact at higher redshifts. The metallicity threshold we infer is much higher than predicted by single-star models and favors a binary progenitor. Our observations also constrain the fraction of cosmic star formation in low-mass galaxies undetectable to Spitzer to be small at z < 4.

Constraints on millisecond magnetars as the engines of prompt emission in gamma-ray bursts

Science.gov (United States)

Beniamini, Paz; Giannios, Dimitrios; Metzger, Brian D.

2017-12-01

We examine millisecond magnetars as central engines of gamma-ray bursts' (GRBs) prompt emission. Using the protomagnetar wind model of Metzger et al., we estimate the temporal evolution of the magnetization and power injection at the base of the GRB jet and apply these to different prompt emission models to make predictions for the GRB energetics, spectra and light curves. We investigate both shock and magnetic reconnection models for the particle acceleration, as well as the effects of energy dissipation across optically thick and thin regions of the jet. The magnetization at the base of the jet, σ0, is the main parameter driving the GRB evolution in the magnetar model and the emission is typically released for 100 ≲σ0 ≲3000. Given the rapid increase in σ0 as the protomagnetar cools and its neutrino-driven mass loss subsides, the GRB duration is typically limited to ≲100 s. This low baryon loading at late times challenges magnetar models for ultralong GRBs, though black hole models likely run into similar difficulties without substantial entrainment from the jet walls. The maximum radiated gamma-ray energy is ≲5 × 1051 erg, significantly less than the magnetar's total initial rotational energy and in strong tension with the high end of the observed GRB energy distribution. However, the gradual magnetic dissipation model applied to a magnetar central engine, naturally explains several key observables of typical GRBs, including energetics, durations, stable peak energies, spectral slopes and a hard to soft evolution during the burst.

THE PEAK ENERGY-DURATION CORRELATION AND POSSIBLE IMPLICATIONS ON GAMMA RAY BURST PROGENITOR

Directory of Open Access Journals (Sweden)

Heon-Young Chang

2006-09-01

Full Text Available We investigate the correlation between the peak energy and the burst duration using available long GRB data with known redshift, whose circumburst medium type has been suggested via afterglow light curve modeling. We find that the peak energy and the burst duration of the observed GRBs are correlated both in the observer frame and in the GRB rest frame. For our total sample we obtain, for instance, the Spearman rank-order correlation values sim 0.75 and sim 0.65 with the chance probabilities P=1.0 times 10^{-3} and P=6.0 times 10^{-3} in the observer frame and in the GRB rest frame, respectively. We note that taking the effects of the expanding universe into account reduces the value a bit. We further attempt to separate our GRB sample into the ``ISM'' GRBs and the ``WIND'' GRBs according to environment models inferred from the afterglow light curves and apply statistical tests, as one may expect that clues on the progenitor of GRBs can be deduced directly from prompt emission properties other than from the ambient environment surrounding GRBs. We find that two subsamples of GRBs show different correlation coefficients. That is, the Spearman rank-order correlation are sim 0.65 and sim 0.57 for the ``ISM'' GRBs and ``WIND'' GRBs, respectively, after taking the effects of the expanding universe into account. It is not yet, however, statistically very much significant that the GRBS in two types of circumburst media show statistically characteristic behaviors, from which one may conclude that all the long bursts are not originated from a single progenitor population. A larger size of data is required to increase the statistical significance.

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.

The ultra-long GRB 111209A. II. Prompt to afterglow and afterglow properties

International Nuclear Information System (INIS)

Stratta, G.; Gendre, B.; Boër, M.; Atteia, J. L.; Coward, D. M.; Howell, E.; De Pasquale, M.; Oates, S.; Klotz, A.; Piro, L.

2013-01-01

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 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.

Fermi GBM Observations During the Second Observing Run of LIGO/Virgo

Science.gov (United States)

Goldstein, Adam; Fermi-GBM

2018-01-01

The Fermi Gamma-ray Burst Monitor (GBM) is a prolific detector of gamma-ray bursts (GRBs) and detects more short duration GRBs than any other instrument currently in operation. Short GRBs are thought to be associated with the mergers of binary neutron star systems (or neutron star-black hole systems), and are therefore considered likely counterparts to gravitational-wave detections from LIGO/Virgo. We report on the GBM observations during the second observing run of LIGO/Virgo and detail the physical and astrophysical insights that might be gleaned from a joint detection of a short GRB and a gravitational-wave source.

Signature of a Newborn Black Hole from the Collapse of a Supra-massive Millisecond Magnetar

Science.gov (United States)

Chen, Wei; Xie, Wei; Lei, Wei-Hua; Zou, Yuan-Chuan; Lü, Hou-Jun; Liang, En-Wei; Gao, He; Wang, Ding-Xiong

2017-11-01

An X-ray plateau followed by a steep decay (“internal plateau”) has been observed in both long and short gamma-ray burst (GRBs), implying that a millisecond magnetar operates in some GRBs. The sharp decay at the end of the plateau, marking the abrupt cessation of the magnetar’s central engine, has been considered the collapse of a supra-massive magnetar into a black hole (BH) when it spins down. If this “internal plateau” is indeed evidence of a magnetar central engine, the natural expectation in some candidates would be a signature from the newborn BH. In this work, we find that GRB 070110 is a particular case which shows a small X-ray bump following its “internal plateau.” We interpret the plateau as a spin-down supra-massive magnetar and the X-ray bump as fallback BH accretion. This indicates that a newborn BH is likely active in some GRBs. Therefore, GRB 070110-like events may provide further support to the magnetar central engine model and enable us to investigate the properties of the magnetar as well as the newborn BH.

Making Preliminary GRBs Real-Time Astronomical Reports

Directory of Open Access Journals (Sweden)

Sebastián Castillo-Carrión

2010-01-01

analysis and evaluation of GRBs. Recently, analysis and evaluation of GRBs were done without help of semiautomated tools or routines; so the time elapsed from the detection until getting all the information produced (DSS-2 data: Digitized Sky Surveys, elevation diagrams in each observatory, etc. could be 30 minutes. The software presented allows to reduce the time elapsed to 30 seconds, getting an email, web, and sms reports.

Expression, refolding and crystallizations of the Grb2-like (GADS) C-terminal SH3 domain complexed with a SLP-76 motif peptide

International Nuclear Information System (INIS)

Faravelli, Alessandro; Dimasi, Nazzareno

2005-01-01

Several crystals of the Grb2-like C-terminal SH3 domain in complex with a motif peptide from the SLP-76 protein were obtained and characterized. The Grb2-like adaptor protein GADS is composed of an N-terminal SH3 domain, an SH2 domain, a proline-rich region and a C-terminal SH3 domain. GADS interacts through its C-terminal SH3 domain with the adaptor protein SLP-76, thus recruiting this protein and other associated molecules to the linker for activation of T-cell (LAT) protein. The DNA encoding the C-terminal SH3 domain of GADS (GADS-cSH3) was assembled synthetically using a recursive PCR technique and the protein was overexpressed in Escherichia coli, refolded and purified. Several crystals of this domain in complex with the SLP-76 peptide were obtained and characterized

Anomalies in the GRBs' distribution

Science.gov (United States)

Bagoly, Zsolt; Horvath, Istvan; Hakkila, Jon; Toth, Viktor

2015-08-01

Gamma-ray bursts (GRBs) are the most luminous objects known: they outshine their host galaxies making them ideal candidates for probing large-scale structure. Earlier, the angular distribution of different GRBs (long, intermediate and short) has been studied in detail with different methods and it has been found that the short and intermediate groups showed deviation from the full randomness at different levels (e.g. Vavrek, R., et al. 2008). However these result based only angular measurements of the BATSE experiment, without any spatial distance indicator involved.Currently we have more than 361 GRBs with measured precise position, optical afterglow and redshift, mainly due to the observations of the Swift mission. This sample is getting large enough that it its homogeneous and isotropic distribution a large scale can be checked. We have recently (Horvath, I. et al., 2014) identified a large clustering of gamma-ray bursts at redshift z ~ 2 in the general direction of the constellations of Hercules and Corona Borealis. This angular excess cannot be entirely attributed to known selection biases, making its existence due to chance unlikely. The scale on which the clustering occurs is disturbingly large, about 2-3 Gpc: the underlying distribution of matter suggested by this cluster is big enough to question standard assumptions about Universal homogeneity and isotropy.

Gamma-ray-burst beaming and gravitational-wave observations.

Science.gov (United States)

Chen, Hsin-Yu; Holz, Daniel E

2013-11-01

Using the observed rate of short-duration gamma-ray bursts (GRBs) it is possible to make predictions for the detectable rate of compact binary coalescences in gravitational-wave detectors. We show that the nondetection of mergers in the existing LIGO/Virgo data constrains the beaming angles and progenitor masses of gamma-ray bursts, although these limits are fully consistent with existing expectations. We make predictions for the rate of events in future networks of gravitational-wave observatories, finding that the first detection of a neutron-star-neutron-star binary coalescence associated with the progenitors of short GRBs is likely to happen within the first 16 months of observation, even in the case of only two observatories (e.g., LIGO-Hanford and LIGO-Livingston) operating at intermediate sensitivities (e.g., advanced LIGO design sensitivity, but without signal recycling mirrors), and assuming a conservative distribution of beaming angles (e.g., all GRBs beamed within θ(j) = 30°). Less conservative assumptions reduce the waiting time until first detection to a period of weeks to months, with an event detection rate of >/~10/yr. Alternatively, the compact binary coalescence model of short GRBs can be ruled out if a binary is not seen within the first two years of operation of a LIGO-Hanford, LIGO-Livingston, and Virgo network at advanced design sensitivity. We also demonstrate that the gravitational wave detection rate of GRB triggered sources (i.e., those seen first in gamma rays) is lower than the rate of untriggered events (i.e., those seen only in gravitational waves) if θ(j)≲30°, independent of the noise curve, network configuration, and observed GRB rate. The first detection in gravitational waves of a binary GRB progenitor is therefore unlikely to be associated with the observation of a GRB.

ON THE HOST GALAXY OF GRB 150101B AND THE ASSOCIATED ACTIVE GALACTIC NUCLEUS

Energy Technology Data Exchange (ETDEWEB)

Xie, Chen [Department of Physics, Xiamen University, Xiamen (China); Fang, Taotao; Wang, Junfeng; Liu, Tong; Jiang, Xiaochuan, E-mail: fangt@xmu.edu.cn [Department of Astronomy and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen (China)

2016-06-20

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 low-luminosity active galactic nuclei (AGNs). Our modeling of the spectral energy distribution 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 ∼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, and the central AGN is likely dominated by a radiatively inefficient accretion flow. Our work explores an interesting connection that may exist between GRB and AGN activities of the host galaxy, which can help in understanding the host environment of the GRB events and the roles of AGN feedback.

ON THE HOST GALAXY OF GRB 150101B AND THE ASSOCIATED ACTIVE GALACTIC NUCLEUS

International Nuclear Information System (INIS)

Xie, Chen; Fang, Taotao; 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 low-luminosity active galactic nuclei (AGNs). Our modeling of the spectral energy distribution 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 ∼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, and the central AGN is likely dominated by a radiatively inefficient accretion flow. Our work explores an interesting connection that may exist between GRB and AGN activities of the host galaxy, which can help in understanding the host environment of the GRB events and the roles of AGN feedback.

A Study of the Gamma-Ray Burst Fundamental Plane

International Nuclear Information System (INIS)

Dainotti, M. G.; Hernandez, X.; Postnikov, S.; Nagataki, S.; O’brien, P.; Willingale, R.; Striegel, S.

2017-01-01

Long gamma-ray bursts (GRBs) with a plateau phase in their X-ray afterglows obey a 3D relation, between the rest-frame time at the end of the plateau, T a , its corresponding X-ray luminosity, L a , and the peak luminosity in the prompt emission, L peak . This 3D relation identifies a GRB fundamental plane whose existence we here confirm. Here we include the most recent GRBs observed by Swift to define a “gold sample” (45 GRBs) and obtain an intrinsic scatter about the plane compatible within 1 σ with the previous result. We compare GRB categories, such as short GRBs with extended emission (SEE), X-ray flashes, GRBs associated with supernovae, a sample of only long-duration GRBs (132), selected from the total sample by excluding GRBs of the previous categories, and the gold sample, composed by GRBs with light curves with good data coverage and relatively flat plateaus. We find that the relation planes for each of these categories are not statistically different from the gold fundamental plane, with the exception of the SSE, which are hence identified as a physically distinct class. The gold fundamental plane has an intrinsic scatter smaller than any plane derived from the other sample categories. Thus, the distance of any particular GRB category from this plane becomes a key parameter. We computed the several category planes with T a as a dependent parameter obtaining for each category smaller intrinsic scatters (reaching a reduction of 24% for the long GRBs). The fundamental plane is independent from several prompt and afterglow parameters.

Modelling the luminosity function of long gamma-ray bursts using Swift and Fermi

Science.gov (United States)

Paul, Debdutta

2018-01-01

I have used a sample of long gamma-ray bursts (GRBs) common to both Swift and Fermi to re-derive the parameters of the Yonetoku correlation. This allowed me to self-consistently estimate pseudo-redshifts of all the bursts with unknown redshifts. This is the first time such a large sample of GRBs from these two instruments is used, both individually and in conjunction, to model the long GRB luminosity function. The GRB formation rate is modelled as the product of the cosmic star formation rate and a GRB formation efficiency for a given stellar mass. An exponential cut-off power-law luminosity function fits the data reasonably well, with ν = 0.6 and Lb = 5.4 × 1052 ergs- 1, and does not require a cosmological evolution. In the case of a broken power law, it is required to incorporate a sharp evolution of the break given by Lb ∼ 0.3 × 1052(1 + z)2.90 erg s- 1, and the GRB formation efficiency (degenerate up to a beaming factor of GRBs) decreases with redshift as ∝ (1 + z)-0.80. However, it is not possible to distinguish between the two models. The derived models are then used as templates to predict the distribution of GRBs detectable by CZT Imager onboard AstroSat as a function of redshift and luminosity. This demonstrates that via a quick localization and redshift measurement of even a few CZT Imager GRBs, AstroSat will help in improving the statistics of GRBs both typical and peculiar.

VERY HIGH ENERGY OBSERVATIONS OF GAMMA-RAY BURSTS WITH STACEE

International Nuclear Information System (INIS)

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

2010-01-01

Gamma-ray bursts (GRBs) are the most powerful explosions known in the universe. Sensitive measurements of the high-energy spectra of GRBs can place important constraints on the burst environments and radiation processes. Until recently, there were no observations during the first few minutes of GRB afterglows in the energy range between 30 GeV and ∼1 TeV. With the launch of the Swift GRB Explorer in late 2004, GRB alerts and localizations within seconds of the bursts became available. The Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) was a ground-based, gamma-ray telescope with an energy threshold of ∼150 GeV for sources at zenith. At the time of Swift's launch, STACEE was in a rare position to provide >150 GeV follow-up observations of GRBs as fast as three minutes after the burst alert. In addition, STACEE performed follow-up observations of several GRBs that were localized by the HETE-2 and INTEGRAL satellites. Between 2002 June and 2007 July, STACEE made follow-up observations of 23 GRBs. Upper limits are placed on the high-energy gamma-ray fluxes from 21 of these bursts.

Gamma-ray bursts and their use as cosmic probes

Science.gov (United States)

2017-01-01

Since the launch of the highly successful and ongoing Swift mission, the field of gamma-ray bursts (GRBs) has undergone a revolution. The arcsecond GRB localizations available within just a few minutes of the GRB alert has signified the continual sampling of the GRB evolution through the prompt to afterglow phases revealing unexpected flaring and plateau phases, the first detection of a kilonova coincident with a short GRB, and the identification of samples of low-luminosity, ultra-long and highly dust-extinguished GRBs. The increased numbers of GRB afterglows, GRB-supernova detections, redshifts and host galaxy associations has greatly improved our understanding of what produces and powers these immense, cosmological explosions. Nevertheless, more high-quality data often also reveal greater complexity. In this review, I summarize some of the milestones made in GRB research during the Swift era, and how previous widely accepted theoretical models have had to adapt to accommodate the new wealth of observational data. PMID:28791158

The Observer’s Guide to the Gamma-Ray Burst Supernova Connection

Directory of Open Access Journals (Sweden)

Zach Cano

2017-01-01

Full Text Available We present a detailed report of the connection between long-duration gamma-ray bursts (GRBs and their accompanying supernovae (SNe. The discussion presented here places emphasis on how observations, and the modelling of observations, have constrained what we know about GRB-SNe. We discuss their photometric and spectroscopic properties, their role as cosmological probes, including their measured luminosity–decline relationships, and how they can be used to measure the Hubble constant. We present a statistical summary of their bolometric properties and use this to determine the properties of the “average” GRB-SN. We discuss their geometry and consider the various physical processes that are thought to power the luminosity of GRB-SNe and whether differences exist between GRB-SNe and the SNe associated with ultra-long-duration GRBs. We discuss how observations of their environments further constrain the physical properties of their progenitor stars and give a brief overview of the current theoretical paradigms of their central engines. We then present an overview of the radioactively powered transients that have been photometrically associated with short-duration GRBs, and we conclude by discussing what additional research is needed to further our understanding of GRB-SNe, in particular the role of binary-formation channels and the connection of GRB-SNe with superluminous SNe.

IMPRINTS OF ELECTRON–POSITRON WINDS ON THE MULTIWAVELENGTH AFTERGLOWS OF GAMMA-RAY BURSTS

International Nuclear Information System (INIS)

Geng, J. J.; Huang, Y. F.; Dai, Z. G.; Wu, X. F.; Li, L.

2016-01-01

Optical rebrightenings in the afterglows of some gamma-ray bursts (GRBs) are unexpected within the framework of the simple external shock model. While it has been suggested that the central engines of some GRBs are newly born magnetars, we aim to relate the behaviors of magnetars to the optical rebrightenings. A newly born magnetar will lose its rotational energy in the form of Poynting-flux, which may be converted into a wind of electron–positron pairs through some magnetic dissipation processes. As proposed by Dai, this wind will catch up with the GRB outflow and a long-lasting reverse shock (RS) would form. By applying this scenario to GRB afterglows, we find that the RS propagating back into the electron–positron wind can lead to an observable optical rebrightening and a simultaneous X-ray plateau (or X-ray shallow decay). In our study, we select four GRBs (i.e., GRB 080413B, GRB 090426, GRB 091029, and GRB 100814A), of which the optical afterglows are well observed and show clear rebrightenings. We find that they can be well interpreted. In our scenario, the spin-down timescale of the magnetar should be slightly smaller than the peak time of the rebrightening, which can provide a clue to the characteristics of the magnetar.

UFFO/ Lomonosov: The Payload for the Observation of Early Photons from Gamma Ray Bursts

Science.gov (United States)

Park, I. H.; Panasyuk, M. I.; Reglero, V.; Chen, P.; Castro-Tirado, A. J.; Jeong, S.; Bogomolov, V.; Brandt, S.; Budtz-Jørgensen, C.; Chang, S.-H.; Chang, Y. Y.; Chen, C.-R.; Chen, C.-W.; Choi, H. S.; Connell, P.; Eyles, C.; Gaikov, G.; Garipov, G.; Huang, J.-J.; Huang, M.-H. A.; Jeong, H. M.; Kim, J. E.; Kim, M. B.; Kim, S.-W.; Lee, H. K.; Lee, J.; Lim, H.; Lin, C.-Y.; Liu, T.-C.; Nam, J. W.; Petrov, V.; Ripa, J.; Rodrigo, J. M.; Svertilov, S.; Wang, M.-Z.; Yashin, I.

2018-02-01

The payload of the UFFO (Ultra-Fast Flash Observatory)-pathfinder now onboard the Lomonosov spacecraft (hereafter UFFO/ Lomonosov) is a dedicated instrument for the observation of GRBs. Its primary aim is to capture the rise phase of the optical light curve, one of the least known aspects of GRBs. Fast response measurements of the optical emission of GRB will be made by a Slewing Mirror Telescope (SMT), a key instrument of the payload, which will open a new frontier in transient studies by probing the early optical rise of GRBs with a response time in seconds for the first time. The SMT employs a rapidly slewing mirror to redirect the optical axis of the telescope to a GRB position prior determined by the UFFO Burst Alert Telescope (UBAT), the other onboard instrument, for the observation and imaging of X-rays. UFFO/Lomonosov was launched successfully from Vostochny, Russia on April 28, 2016, and will begin GRB observations after completion of functional checks of the Lomonosov spacecraft. The concept of early GRB photon measurements with UFFO was reported in 2012. In this article, we will report in detail the first mission, UFFO/Lomonosov, for the rapid response to GRB observations.

Magnetized Reverse Shock: Density-fluctuation-induced Field Distortion, Polarization Degree Reduction, and Application to GRBs

Energy Technology Data Exchange (ETDEWEB)

Deng Wei; Zhang Bing [Department of Physics and Astronomy, University of Nevada Las Vegas, Las Vegas, NV 89154 (United States); Li Hui [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Stone, James M., E-mail: deng@physics.unlv.edu, E-mail: zhang@physics.unlv.edu, E-mail: hli@lanl.gov, E-mail: jstone@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544-1001 (United States)

2017-08-10

The early optical afterglow emission of several gamma-ray bursts (GRBs) shows a high linear polarization degree (PD) of tens of percent, suggesting an ordered magnetic field in the emission region. The light curves are consistent with being of a reverse shock (RS) origin. However, the magnetization parameter, σ , of the outflow is unknown. If σ is too small, an ordered field in the RS may be quickly randomized due to turbulence driven by various perturbations so that the PD may not be as high as observed. Here we use the “Athena++” relativistic MHD code to simulate a relativistic jet with an ordered magnetic field propagating into a clumpy ambient medium, with a focus on how density fluctuations may distort the ordered magnetic field and reduce PD in the RS emission for different σ values. For a given density fluctuation, we discover a clear power-law relationship between the relative PD reduction and the σ value of the outflow. Such a relation may be applied to estimate σ of the GRB outflows using the polarization data of early afterglows.

TeV-PeV neutrinos from low-power gamma-ray burst jets inside stars.

Science.gov (United States)

Murase, Kohta; Ioka, Kunihito

2013-09-20

We study high-energy neutrino production in collimated jets inside progenitors of gamma-ray bursts (GRBs) and supernovae, considering both collimation and internal shocks. We obtain simple, useful constraints, using the often overlooked point that shock acceleration of particles is ineffective at radiation-mediated shocks. Classical GRBs may be too powerful to produce high-energy neutrinos inside stars, which is consistent with IceCube nondetections. We find that ultralong GRBs avoid such constraints and detecting the TeV signal will support giant progenitors. Predictions for low-power GRB classes including low-luminosity GRBs can be consistent with the astrophysical neutrino background IceCube may detect, with a spectral steepening around PeV. The models can be tested with future GRB monitors.

No supernovae detected in two long-duration gamma-ray bursts.

Science.gov (United States)

Watson, D; Fynbo, J P U; Thöne, C C; Sollerman, J

2007-05-15

There is strong evidence that long-duration gamma-ray bursts (GRBs) are produced during the collapse of a massive star. In the standard version of the collapsar model, a broad-lined and luminous Type Ic core-collapse supernova (SN) accompanies the GRB. This association has been confirmed in observations of several nearby GRBs. Recent observations show that some long-duration GRBs are different. No SN emission accompanied the long-duration GRBs 060505 and 060614 down to limits fainter than any known Type Ic SN and hundreds of times fainter than the archetypal SN 1998bw that accompanied GRB 980425. Multi-band observations of the early afterglows, as well as spectroscopy of the host galaxies, exclude the possibility of significant dust obscuration. Furthermore, the bursts originated in star-forming galaxies, and in the case of GRB 060505, the burst was localized to a compact star-forming knot in a spiral arm of its host galaxy. We find that the properties of the host galaxies, the long duration of the bursts and, in the case of GRB 060505, the location of the burst within its host, all imply a massive stellar origin. The absence of an SN to such deep limits therefore suggests a new phenomenological type of massive stellar death.

Grb7 binds to Hax-1 and undergoes an intramolecular domain association that offers a model for Grb7 regulation

OpenAIRE

Siamakpour-Reihani, Sharareh; Peterson, Tabitha A.; Bradford, Andrew M.; Argiros, Haroula J.; Haas, Laura Lowell; Lor, Siamee N.; Haulsee, Zachary M.; Spuches, Anne M.; Johnson, Dennis L.; Rohrschneider, Larry R.; Shuster, Charles Brad; Lyons, Barbara A.

2011-01-01

Adaptor proteins mediate signal transduction from cell surface receptors to downstream signaling pathways. The Grb7 protein family of adaptor proteins is constituted by Grb7, Grb10, and Grb14. This protein family has been shown to be overexpressed in certain cancers and cancer cell lines. Grb7-mediated cell migration has been shown to proceed through a focal adhesion kinase (FAK)/Grb7 pathway, although the specific participants downstream of Grb7 in cell migration signaling have not been full...

Polarimetry and Photometry of Gamma-Ray Bursts with RINGO2

Science.gov (United States)

Steele, I. A.; Kopač, D.; Arnold, D. M.; Smith, R. J.; Kobayashi, S.; Jermak, H. E.; Mundell, C. G.; Gomboc, A.; Guidorzi, C.; Melandri, A.; Japelj, J.

2017-07-01

We present a catalog of early-time (˜ {10}2-{10}4 s) photometry and polarimetry of all gamma-ray burst (GRB) optical afterglows observed with the RINGO2 imaging polarimeter on the Liverpool Telescope. Of the 19 optical afterglows observed, the following nine were bright enough to perform photometry and attempt polarimetry: GRB 100805A, GRB 101112A, GRB 110205A, GRB 110726A, GRB 120119A, GRB 120308A, GRB 120311A, GRB 120326A, and GRB 120327A. We present multiwavelength light curves for these 9 GRBs, together with estimates of their optical polarization degrees and/or limits. We carry out a thorough investigation of detection probabilities, instrumental properties, and systematics. Using two independent methods, we confirm previous reports of significant polarization in GRB 110205A and 120308A, and report the new detection of P={6}-2+3% in GRB101112A. We discuss the results for the sample in the context of the reverse- and forward-shock afterglow scenario, and show that GRBs with detectable optical polarization at early time have clearly identifiable signatures of reverse-shock emission in their optical light curves. This supports the idea that GRB ejecta contain large-scale magnetic fields, and it highlights the importance of rapid-response polarimetry.

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.

A Study of the Gamma-Ray Burst Fundamental Plane

Energy Technology Data Exchange (ETDEWEB)

Dainotti, M. G. [Department of Physics and Astronomy, Stanford University, Via Pueblo Mall 382, Stanford, CA 94305-4060 (United States); Hernandez, X. [Instituto de Astronomía, Universidad Nacional Autónoma de México, Ciudad de México 04510, México (Mexico); Postnikov, S. [The Center for Exploration of Energy and Matter, Indiana University, Bloomington, IN 47405 (United States); Nagataki, S. [RIKEN, Hirosawa, Wako Saitama (Japan); O’brien, P.; Willingale, R. [Department of Physics and Astronomy, University of Leicester, Road Leicester LE1 7RH (United Kingdom); Striegel, S., E-mail: mdainott@stanford.edu, E-mail: dainotti@oa.uj.edu.pl, E-mail: mariagiovannadainotti@yahoo.it, E-mail: xavier@astro.unam.mx, E-mail: postsergey@gmail.com, E-mail: shigehiro.nagataki@riken.jp, E-mail: zrw@le.ac.uk, E-mail: stephanie.striegel@sjsu.edu [Department of Physics and Astronomy, San Jose State University, One Washington Square, San Jose, CA 95192 (United States)

2017-10-20

Long gamma-ray bursts (GRBs) with a plateau phase in their X-ray afterglows obey a 3D relation, between the rest-frame time at the end of the plateau, T {sub a} , its corresponding X-ray luminosity, L {sub a} , and the peak luminosity in the prompt emission, L {sub peak}. This 3D relation identifies a GRB fundamental plane whose existence we here confirm. Here we include the most recent GRBs observed by Swift to define a “gold sample” (45 GRBs) and obtain an intrinsic scatter about the plane compatible within 1 σ with the previous result. We compare GRB categories, such as short GRBs with extended emission (SEE), X-ray flashes, GRBs associated with supernovae, a sample of only long-duration GRBs (132), selected from the total sample by excluding GRBs of the previous categories, and the gold sample, composed by GRBs with light curves with good data coverage and relatively flat plateaus. We find that the relation planes for each of these categories are not statistically different from the gold fundamental plane, with the exception of the SSE, which are hence identified as a physically distinct class. The gold fundamental plane has an intrinsic scatter smaller than any plane derived from the other sample categories. Thus, the distance of any particular GRB category from this plane becomes a key parameter. We computed the several category planes with T {sub a} as a dependent parameter obtaining for each category smaller intrinsic scatters (reaching a reduction of 24% for the long GRBs). The fundamental plane is independent from several prompt and afterglow parameters.

A MAD Explanation for the Correlation between Bulk Lorentz Factor and Minimum Variability Timescale

Science.gov (United States)

Lloyd-Ronning, Nicole; Lei, Wei-hua; Xie, Wei

2018-04-01

We offer an explanation for the anti-correlation between the minimum variability timescale (MTS) in the prompt emission light curve of gamma-ray bursts (GRBs) and the estimated bulk Lorentz factor of these GRBs, in the context of a magnetically arrested disk (MAD) model. In particular, we show that previously derived limits on the maximum available energy per baryon in a Blandford-Znajek jet leads to a relationship between the characteristic MAD timescale in GRBs and the maximum bulk Lorentz factor: tMAD∝Γ-6, somewhat steeper than (although within the error bars of) the fitted relationship found in the GRB data. Similarly, the MAD model also naturally accounts for the observed anti-correlation between MTS and gamma-ray luminosity L in the GRB data, and we estimate the accretion rates of the GRB disk (given these luminosities) in the context of this model. Both of these correlations (MTS - Γ and MTS - L) are also observed in the AGN data, and we discuss the implications of our results in the context of both GRB and blazar systems.

Toward a Better Understanding of the GRB Phenomenon: a New Model for GRB Prompt Emission and its Effects on the New LiNT- Epeak,irest,NT Relation

Science.gov (United States)

Guiriec, S.; Kouveliotou, C.; Daigne, F.; Zhang, B.; Hascoët, R.; Nemmen, R. S.; Thompson, D. J.; Bhat, P. N.; Gehrels, N.; Gonzalez, M. M.; Kaneko, Y.; McEnery, J.; Mochkovitch, R.; Racusin, J. L.; Ryde, F.; Sacahui, J. R.; Ünsal, A. M.

2015-07-01

Gamma-ray burst (GRB) prompt emission spectra in the keV-MeV energy range are usually considered to be adequately fitted with the empirical Band function. Recent observations with the Fermi Gamma-ray Space Telescope (Fermi) revealed deviations from the Band function, sometimes in the form of an additional blackbody (BB) component, while on other occasions in the form of an additional power law (PL) component extending to high energies. In this article we investigate the possibility that the three components may be present simultaneously in the prompt emission spectra of two very bright GRBs (080916C and 090926A) observed with Fermi, and how the three components may affect the overall shape of the spectra. While the two GRBs are very different when fitted to a single Band function, they look like “twins” in the three-component scenario. Through fine-time spectroscopy down to the 100 ms timescale, we follow the evolution of the various components. We succeed in reducing the number of free parameters in the three-component model, which results in a new semi-empirical model—but with physical motivations—to be competitive with the Band function in terms of number of degrees of freedom. From this analysis using multiple components, the Band function is globally the most intense component, although the additional PL can overpower the others in sharp time structures. The Band function and the BB component are the most intense at early times and globally fade across the burst duration. The additional PL is the most intense component at late time and may be correlated with the extended high-energy emission observed thousands of seconds after the burst with Fermi/Large Area Telescope. Unexpectedly, this analysis also shows that the additional PL may be present from the very beginning of the burst, where it may even overpower the other components at low energy. We investigate the effect of the three components on the new time-resolved luminosity-hardness relation in

Long Gamma-Ray Bursts without Visible Supernovae A Case Study of Redshift Estimators and Alleged Novel Objects

CERN Document Server

Dado, Shlomo; De Rújula, A; Plaga, Rainer

2008-01-01

It has been argued that the observational limits on a supernova (SN) associated with GRB 060614 convincingly exclude a SN akin to SN 1998bw as its originator and provide evidence for a new class of long-duration GRBs. We discuss this issue in the contexts of indirect "redshift estimators" and of the fireball and cannonball models of GRBs. The latter explains the unusual properties of GRB 060614: at its debated but favored low redshift (0.125), they are predicted, as opposed to exceptional, if the associated core-collapse SN is of a recently discovered, very faint type. We take the occasion to discuss the association between GRBs and SNe.

DISCOVERY OF RADIO AFTERGLOW FROM THE MOST DISTANT COSMIC EXPLOSION

International Nuclear Information System (INIS)

Chandra, Poonam; Frail, Dale A.; Fox, Derek; Kulkarni, Shrinivas; Harrsion, Fiona; Kasliwal, Mansi; Berger, Edo; Cenko, S. Bradley; Bock, Douglas C.-J.

2010-01-01

We report on the discovery of radio afterglow emission from the gamma-ray burst GRB 090423, which exploded at a redshift of 8.3, making it the object with the highest known redshift in the universe. By combining our radio measurements with existing X-ray and infrared observations, we estimate the kinetic energy of the afterglow, the geometry of the outflow, and the density of the circumburst medium. Our best-fit model suggests a quasi-spherical, high-energy explosion in a low, constant-density medium. GRB 090423 had a similar energy release to the other well-studied high redshift GRB 050904 (z = 6.26), but their circumburst densities differ by 2 orders of magnitude. We compare the properties of GRB 090423 with a sample of gamma-ray bursts (GRBs) at moderate redshifts. We find that the high energy and afterglow properties of GRB 090423 are not sufficiently different from other GRBs to suggest a different kind of progenitor, such as a Population III (Pop III) star. However, we argue that it is not clear that the afterglow properties alone can provide convincing identification of Pop III progenitors. We suggest that the millimeter and centimeter radio detections of GRB 090423 at early times contained emission from the reverse shock. If true, this may have important implications for the detection of high-redshift GRBs by the next generation of radio facilities.

Gamma-Ray Bursts The Brightest Explosions in the Universe

CERN Document Server

Vedrenne, Gilbert

2009-01-01

Since their discovery was first announced in 1973, gamma-ray bursts (GRBs) have been among the most fascination objects in the universe. While the initial mystery has gone, the fascination continues, sustained by the close connection linking GRBs with some of the most fundamental topics in modern astrophysics and cosmology. Both authors have been active in GRB observations for over two decades and have produced an outstanding account on both the history and the perspectives of GRB research.

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

International Nuclear Information System (INIS)

D'Elia, V.; Fiore, F.; Piranomonte, S.; Sbordone, L.; Stella, L.; Antonelli, L.A.; Fontana, A.; Giannini, T.; Guetta, D.; Israel, G.; Testa, V.; Meurs, E.J.A.; Vergani, S.D.; Ward, P.; Chincarini, G.; Tagliaferri, G.; Campana, S.; Fugazza, D.; Molinari, E.; Moretti, A.; Chincarini, G.; Melandri, A.; Norci, L.; Vergani, S.D.; Pellizza, L.; Filliatre, P.; Perna, R.; Lazzati, D.

2007-01-01

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 -1 at 4200 Angstroms and 6.6 kms -1 at 9000 Angstroms of the optical afterglow of GRB050730, obtained with UVES-VLT ∼ 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 -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 smaller than that of

The Properties of Short Gamma-Ray Burst Jets Triggered by Neutron Star Mergers

Energy Technology Data Exchange (ETDEWEB)

Murguia-Berthier, Ariadna; Ramirez-Ruiz, Enrico; Montes, Gabriela [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); De Colle, Fabio [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, A. P. 70-543 04510 D. F. (Mexico); Rezzolla, Luciano; Takami, Kentaro [Institute for Theoretical Physics, Goethe University, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main (Germany); Rosswog, Stephan [Astronomy and Oskar Klein Centre, Stockholm University, AlbaNova, SE-106 91 Stockholm (Sweden); Perego, Albino [Institut für Kernphysik, Technische Universität Darmstadt, D-64289 Darmstadt (Germany); Lee, William H. [Instituto de Astronomía, Universidad Nacional Autónoma de México, A. P. 70-264 04510 D. F. (Mexico)

2017-02-01

The most popular model for short gamma-ray bursts (sGRBs) involves the coalescence of binary neutron stars. Because the progenitor is actually hidden from view, we must consider under which circumstances such merging systems are capable of producing a successful sGRB. Soon after coalescence, winds are launched from the merger remnant. In this paper, we use realistic wind profiles derived from global merger simulations in order to investigate the interaction of sGRB jets with these winds using numerical simulations. We analyze the conditions for which these axisymmetric winds permit relativistic jets to break out and produce an sGRB. We find that jets with luminosities comparable to those observed in sGRBs are only successful when their half-opening angles are below ≈20°. This jet collimation mechanism leads to a simple physical interpretation of the luminosities and opening angles inferred for sGRBs. If wide, low-luminosity jets are observed, they might be indicative of a different progenitor avenue such as the merger of a neutron star with a black hole. We also use the observed durations of sGRB to place constraints on the lifetime of the wind phase, which is determined by the time it takes the jet to break out. In all cases we find that the derived limits argue against completely stable remnants for binary neutron star mergers that produce sGRBs.

EARLY OPTICAL OBSERVATIONS OF GAMMA-RAY BURSTS BY THE TAROT TELESCOPES: PERIOD 2001-2008

International Nuclear Information System (INIS)

Klotz, A.; Boer, M.; Atteia, J. L.; Gendre, B.

2009-01-01

The Telescopes a Action Rapide pour les Objets Transitoires telescopes are two robotic observatories designed to observe the prompt optical emission counterpart and the early afterglow of gamma-ray bursts (GRBs). We present data acquired between 2001 and 2008 and discuss the properties of the optical emission of GRBs, noting various interesting results. The optical emission observed during the prompt GRB phase is rarely very bright: we estimate that 5%-20% of GRBs exhibit a bright optical flash (R < 14) during the prompt gamma-ray emission, and that more than 50% of the GRBs have an optical emission fainter than R = 15.5 when the gamma-ray emission is active. We study the apparent optical brightness distribution of GRBs at 1000 s showing that our observations confirm the distribution derived by other groups. The combination of these results with those obtained by other rapid slewing telescopes allows us to better characterize the early optical emission of GRBs and to emphasize the importance of very early multiwavelength GRB studies for the understanding of the physics of the ejecta.

Direct association between the Ret receptor tyrosine kinase and the Src homology 2-containing adapter protein Grb7.

Science.gov (United States)

Pandey, A; Liu, X; Dixon, J E; Di Fiore, P P; Dixit, V M

1996-05-03

Adapter proteins containing Src homology 2 (SH2) domains link transmembrane receptor protein-tyrosine kinases to downstream signal transducing molecules. A family of SH2 containing adapter proteins including Grb7 and Grb10 has been recently identified. We had previously shown that Grb10 associates with Ret via its SH2 domain in an activation-dependent manner (Pandey, A., Duan, H., Di Fiore, P.P., and Dixit, V.M. (1995) J. Biol, Chem. 270, 21461-21463). We now demonstrate that the related adapter molecule Grb7 also associates with Ret in vitro and in vivo, and that the binding of the SH2 domain of Grb7 to Ret is direct. This binding is dependent upon Ret autophosphorylation since Grb7 is incapable of binding a kinase-defective mutant of Ret. Thus two members of the Grb family, Grb7 and Grb10, likely relay signals emanating from Ret to other, as yet, unidentified targets within the cell.

Modeling and simulation of aggregation of membrane protein LAT with molecular variability in the number of binding sites for cytosolic Grb2-SOS1-Grb2.

Directory of Open Access Journals (Sweden)

Ambarish Nag

Full Text Available The linker for activation of T cells (LAT, the linker for activation of B cells (LAB, and the linker for activation of X cells (LAX form a family of transmembrane adaptor proteins widely expressed in lymphocytes. These scaffolding proteins have multiple binding motifs that, when phosphorylated, bind the SH2 domain of the cytosolic adaptor Grb2. Thus, the valence of LAT, LAB and LAX for Grb2 is variable, depending on the strength of receptor activation that initiates phosphorylation. During signaling, the LAT population will exhibit a time-varying distribution of Grb2 valences from zero to three. In the cytosol, Grb2 forms 1:1 and 2:1 complexes with the guanine nucleotide exchange factor SOS1. The 2:1 complex can bridge two LAT molecules when each Grb2, through their SH2 domains, binds to a phosphorylated site on a separate LAT. In T cells and mast cells, after receptor engagement, receptor phosphoyrlation is rapidly followed by LAT phosphorylation and aggregation. In mast cells, aggregates containing more than one hundred LAT molecules have been detected. Previously we considered a homogeneous population of trivalent LAT molecules and showed that for a range of Grb2, SOS1 and LAT concentrations, an equilibrium theory for LAT aggregation predicts the formation of a gel-like phase comprising a very large aggregate (superaggregate. We now extend this theory to investigate the effects of a distribution of Grb2 valence in the LAT population on the formation of LAT aggregates and superaggregate and use stochastic simulations to calculate the fraction of the total LAT population in the superaggregate.

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.

GRB 130606A AS A PROBE OF THE INTERGALACTIC MEDIUM AND THE INTERSTELLAR MEDIUM IN A STAR-FORMING GALAXY IN THE FIRST Gyr AFTER THE BIG BANG

International Nuclear Information System (INIS)

Chornock, Ryan; Berger, Edo; Lunnan, Ragnhild; Drout, Maria R.; Fong Wenfai; Laskar, Tanmoy; Fox, Derek B.; Roth, Katherine C.

2013-01-01

We present high signal-to-noise ratio Gemini and MMT spectroscopy of the optical afterglow of the gamma-ray burst (GRB) 130606A at redshift z = 5.913, discovered by Swift. This is the first high-redshift GRB afterglow to have spectra of comparable quality to those of z ≈ 6 quasars. The data exhibit a smooth continuum at near-infrared wavelengths that is sharply cut off blueward of 8410 Å due to absorption from Lyα at redshift z ≈ 5.91, with some flux transmitted through the Lyα forest between 7000 and 7800 Å. We use column densities inferred from metal absorption lines to constrain the metallicity of the host galaxy between a lower limit of [Si/H] ∼> –1.7 and an upper limit of [S/H] ∼ GP eff (Lyα) > 6.4). This is comparable to the lowest-redshift Gunn-Peterson troughs found in quasar spectra. Some Lyβ and Lyγ transmission is detected in this redshift window, indicating that it is not completely opaque, and hence that the intergalactic medium (IGM) is nonetheless mostly ionized at these redshifts. We set a 2σ upper limit of 0.11 on the neutral fraction of the IGM at the redshift of the GRB from the lack of a Lyα red damping wing, assuming a model with a constant neutral density. GRB 130606A thus for the first time realizes the promise of GRBs as probes of the first galaxies and cosmic reionization

Extinction of gamma-ray burst afterglows as a diagnostic of the location of cosmic star formation

Science.gov (United States)

Ramirez-Ruiz, Enrico; Trentham, Neil; Blain, A. W.

2002-01-01

The properties of gamma-ray bursts (GRBs) and their afterglows are used to investigate the location of star formation activity through the history of the Universe. This approach is motivated by the following: (i) GRBs are thought to be associated with the deaths of massive stars and so the GRB rate ought to follow the formation rate of massive stars; (ii) GRBs are the last phase of the evolution of these stars, which do not live long enough to travel far from their place of birth, and so GRBs are located where the stars formed; and (iii) GRB afterglows occur over both X-ray and optical wavelengths, and so the differential effects of dust extinction between the two wavebands can reveal whether or not large amounts of dust are present in galaxies hosting GRBs. Recent evidence suggests that a significant fraction of stars in the Universe formed in galaxies that are bright at rest-frame submillimetre (submm) and infrared wavelengths rather than at ultraviolet wavelengths; we estimate about three quarters of the star formation in the Universe occurred in the submm-bright mode. High-redshift submm-selected galaxies are thought to have properties similar to local ultraluminous infrared galaxies (ULIGs) such as Arp 220, based on the concordance between their luminosities and spectral energy distributions. If this is the case, then GRBs in submm-bright galaxies should have their optical afterglows extinguished by internal dust absorption, but only very few should have their 2-10keV X-ray afterglows obscured. The value that we quote of three quarters is marginally consistent with observations of GRBs: 60+/-15 per cent of GRBs have no detected optical afterglow, whereas almost all have an X-ray afterglow. A more definitive statement could be made with observations of soft X-ray afterglows (0.5-2keV), in which extinction should be severe for GRBs located in submm-bright galaxies with gas densities similar to those in local ULIGs. If the X-ray afterglows disappear at soft X

A time-dependent search for high-energy neutrinos from bright GRBs with ANTARES

Directory of Open Access Journals (Sweden)

Celli Silvia

2017-01-01

Full Text Available Astrophysical point-like neutrino sources, like Gamma-Ray Bursts (GRBs, are one of the main targets for neutrino telescopes, since they are among the best candidates for Ultra-High-Energy Cosmic Ray (UHECR acceleration. From the interaction between the accelerated protons and the intense radiation fields of the source jet, charged mesons are produced, which then decay into neutrinos. The methods and the results of a search for high-energy neutrinos in spatial and temporal correlation with the detected gamma-ray emission are presented for four bright GRBs observed between 2008 and 2013: a time-dependent analysis, optimised for each flare of the selected bursts, is performed to predict detailed neutrino spectra. The internal shock scenario of the fireball model is investigated, relying on the neutrino spectra computed through the numerical code NeuCosmA. The analysis is optimized on a per burst basis, through the maximization of the signal discovery probability. Since no events in ANTARES data passed the optimised cuts, 90% C.L. upper limits are derived on the expected neutrino fluences.

Cosmic-ray and neutrino emission from Gamma-Ray Bursts with a nuclear cascade

Energy Technology Data Exchange (ETDEWEB)

Biehl, Daniel; Boncioli, Denise; Fedynitch, Anatoli; Winter, Walter

2017-05-24

We discuss neutrino and cosmic-ray emission from Gamma-Ray Bursts (GRBs) with the injection of nuclei, where we take into account that a nuclear cascade from photo-disintegration can fully develop in the source. One of our main objectives is to test if recent results from the IceCube and the Pierre Auger Observatory can be accommodated with the paradigm that GRBs are the sources of Ultra-High Energy Cosmic Rays (UHECRs). While our key results are obtained using an internal shock model, we discuss how the secondary emission from a GRB shell can be interpreted in terms of other astrophysical models. It is demonstrated that the expected neutrino flux from GRBs weakly depends on the injection composition, which implies that prompt neutrinos from GRBs can efficiently test the GRB-UHECR paradigm even if the UHECRs are nuclei. We show that the UHECR spectrum and composition, as measured by the Pierre Auger Observatory, can be self-consistently reproduced in a combined source-propagation model. In an attempt to describe the energy range including the ankle, we find tension with the IceCube bounds from the GRB stacking analyses. In an alternative scenario, where only the UHECRs beyond the ankle originate from GRBs, the requirement for a joint description of cosmic-ray and neutrino observations favors lower luminosities, which does not correspond to the typical expectation from γ-ray observations.

Cosmic-ray and neutrino emission from Gamma-Ray Bursts with a nuclear cascade

International Nuclear Information System (INIS)

Biehl, Daniel; Boncioli, Denise; Fedynitch, Anatoli; Winter, Walter

2017-01-01

We discuss neutrino and cosmic-ray emission from Gamma-Ray Bursts (GRBs) with the injection of nuclei, where we take into account that a nuclear cascade from photo-disintegration can fully develop in the source. One of our main objectives is to test if recent results from the IceCube and the Pierre Auger Observatory can be accommodated with the paradigm that GRBs are the sources of Ultra-High Energy Cosmic Rays (UHECRs). While our key results are obtained using an internal shock model, we discuss how the secondary emission from a GRB shell can be interpreted in terms of other astrophysical models. It is demonstrated that the expected neutrino flux from GRBs weakly depends on the injection composition, which implies that prompt neutrinos from GRBs can efficiently test the GRB-UHECR paradigm even if the UHECRs are nuclei. We show that the UHECR spectrum and composition, as measured by the Pierre Auger Observatory, can be self-consistently reproduced in a combined source-propagation model. In an attempt to describe the energy range including the ankle, we find tension with the IceCube bounds from the GRB stacking analyses. In an alternative scenario, where only the UHECRs beyond the ankle originate from GRBs, the requirement for a joint description of cosmic-ray and neutrino observations favors lower luminosities, which does not correspond to the typical expectation from γ-ray observations.

The MUSE view of the host galaxy of GRB 100316D

Science.gov (United States)

Izzo, L.; Thöne, C. C.; Schulze, S.; Mehner, A.; Flores, H.; Cano, Z.; de Ugarte Postigo, A.; Kann, D. A.; Amorín, R.; Anderson, J. P.; Bauer, F. E.; Bensch, K.; Christensen, L.; Covino, S.; Della Valle, M.; Fynbo, J. P. U.; Jakobsson, P.; Klose, S.; Kuncarayakti, H.; Leloudas, G.; Milvang-Jensen, B.; Møller, P.; Puech, M.; Rossi, A.; Sánchez-Ramírez, R.; Vergani, S. D.

2017-12-01

The low distance, z = 0.0591, of GRB 100316D and its association with SN 2010bh represent two important motivations for studying this host galaxy and the GRB's immediate environment with the integral field spectrographs like Very Large Telescope/Multi-Unit Spectroscopic Explorer. Its large field of view allows us to create 2D maps of gas metallicity, ionization level and the star formation rate (SFR) distribution maps, as well as to investigate the presence of possible host companions. The host is a late-type dwarf irregular galaxy with multiple star-forming regions and an extended central region with signatures of on-going shock interactions. The gamma-ray burst (GRB) site is characterized by the lowest metallicity, the highest SFR and the youngest (∼20-30 Myr) stellar population in the galaxy, which suggest a GRB progenitor stellar population with masses up to 20-40 M⊙. We note that the GRB site has an offset of ∼660 pc from the most luminous SF region in the host. The observed SF activity in this galaxy may have been triggered by a relatively recent gravitational encounter between the host and a small undetected (LH α ≤ 1036 erg s-1) companion.

Search for the signatures of a new-born black hole from the collapse of a supra-massive millisecond magnetar in short GRB light curves

Science.gov (United States)

Zhang, Q.; Lei, W. H.; Zhang, B. B.; Chen, W.; Xiong, S. L.; Song, L. M.

2018-03-01

`Internal plateau' followed by a sharp decay is commonly seen in short gamma-ray burst (GRB) light curves. The plateau component is usually interpreted as the dipole emission from a supra-massive magnetar, and the sharp decay may imply the collapse of the magnetar to a black hole (BH). Fall-back accretion on to the new-born BH could produce long-lasting activities via the Blandford-Znajek (BZ) process. The magnetic flux accumulated near the BH would be confined by the accretion discs for a period of time. As the accretion rate decreases, the magnetic flux is strong enough to obstruct gas infall, leading to a magnetically arrested disc. Within this scenario, we show that the BZ process could produce two types of typical X-ray light curves: type I exhibits a long-lasting plateau, followed by a power-law (PL) decay with slopes ranging from 5/3 to 40/9; type II shows roughly a single PL decay with a slope of 5/3. The former requires low magnetic field strength, while the latter corresponds to relatively high values. We search for such signatures of the new-born BH from a sample of short GRBs with an internal plateau, and find two candidates: GRB 101219A and GRB 160821B, corresponding to type II and type I light curves, respectively. It is shown that our model can explain the data very well.

Searching gamma-ray bursts for gravitational lensing echoes - Implications for compact dark matter

Science.gov (United States)

Nemiroff, R. J.; Norris, J. P.; Wickramasinghe, W. A. D. T.; Horack, J. M.; Kouveliotou, C.; Fishman, G. J.; Meegan, C. A.; Wilson, R. B.; Paciesas, W. S.

1993-01-01

The first available 44 gamma-ray bursts (GRBs) detected by the Burst and Transient Source Experiment on board the Compton Gamma-Ray Observatory have been inspected for echo signals following shortly after the main signal. No significant echoes have been found. Echoes would have been expected were the GRBs distant enough and the universe populated with a sufficient density of compact objects composing the dark matter. Constraints on dark matter abundance and GRB redshifts from the present data are presented and discussed. Based on these preliminary results, a universe filled to critical density of compact objects between 10 exp 6.5 and 10 exp 8.1 solar masses are now marginally excluded, or the most likely cosmological distance paradigm for GRBs is not correct. We expect future constraints to be able either to test currently popular cosmological dark matter paradigms or to indicate that GRBs do not lie at cosmological distances.

Prospects for Gamma-Ray Burst detection by the Cherenkov Telescope Array

Directory of Open Access Journals (Sweden)

Bissaldi E.

2017-01-01

Full Text Available The Large Area Telescope (LAT on the Fermi satellite is expected to publish a catalogue with more than 100 Gamma-Ray Bursts (GRBs detected above 100 MeV thanks to a new detection algorithm and a new event reconstruction. This work aims at revising the prospects for GRB alerts with the Cherenkov Telescope Array (CTA based on the new LAT results. We start considering the simulation of the observations with the full CTA of two extremely bright events, the long GRB 130427A and the short GRB 090510, then we investigate how these GRBs would be observed by a particular configuration of the array with the telescopes pointing to different directions in what is called the “coupled divergent mode”.

Fermi and Swift Gamma-Ray Burst Afterglow Population Studies

Science.gov (United States)

Racusin, Judith L.; Oates, S. R.; Schady, P.; Burrows, D. N.; dePasquale, M.; Donato, D.; Gehrels, N.; Koch, S.; McEnery, J.; Piran, T.;

AN EXTERNAL SHOCK ORIGIN OF GRB 141028A

Energy Technology Data Exchange (ETDEWEB)

Burgess, J. Michael; Bégué, Damien; Ryde, Felix [The Oskar Klein Centre for Cosmoparticle Physics, AlbaNova, SE-106 91 Stockholm (Sweden); Omodei, Nicola [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); Pe’er, Asaf [Physics Department, University College Cork, Cork (Ireland); Racusin, J. L.; Cucchiara, A., E-mail: jamesb@kth.se, E-mail: damienb@kth.se [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2016-05-10

The prompt emission of the long, smooth, and single-pulsed gamma-ray burst, GRB 141028A, is analyzed under the guise of an external shock model. First, we fit the γ -ray spectrum with a two-component photon model, namely, synchrotron+blackbody, and then fit the recovered evolution of the synchrotron νF{sub ν} peak to an analytic model derived considering the emission of a relativistic blast wave expanding into an external medium. The prediction of the model for the νF{sub ν} peak evolution matches well with the observations. We observe the blast wave transitioning into the deceleration phase. Furthermore, we assume the expansion of the blast wave to be nearly adiabatic, motivated by the low magnetic field deduced from the observations. This allows us to recover within an order of magnitude the flux density at the νF{sub ν} peak, which is remarkable considering the simplicity of the analytic model. Under this scenario we argue that the distinction between prompt and afterglow emission is superfluous as both early-time emission and late-time emission emanate from the same source. While the external shock model is clearly not a universal solution, this analysis opens the possibility that at least some fraction of GRBs can be explained with an external shock origin of their prompt phase.

Status report of the UFFO-pathfinder

DEFF Research Database (Denmark)

A. Huang, M-H; Park, I.L.; Ahmad, S.

2013-01-01

Gamma-Ray Bursts (GRBs) are the most energetic explosions in the universe, their optical photonflux rise very quickly, typically within one minute, then fall off gradually. Hundreds of GRBs optical light curveshave been measured since the first discovery of GRB in 1967. However, only a handful of...

Scientific prospects for spectroscopy of the gamma-ray burst prompt emission with SVOM

Science.gov (United States)

Bernardini, M. G.; Xie, F.; Sizun, P.; Piron, F.; Dong, Y.; Atteia, J.-L.; Antier, S.; Daigne, F.; Godet, O.; Cordier, B.; Wei, J.

2017-10-01

SVOM (Space-based multi-band astronomical Variable Objects Monitor) is a Sino-French space mission dedicated to the study of Gamma-Ray Bursts (GRBs) in the next decade, capable to detect and localise the GRB emission, and to follow its evolution in the high-energy and X-ray domains, and in the visible and NIR bands. The satellite carries two wide-field high-energy instruments: a coded-mask gamma-ray imager (ECLAIRs; 4-150 keV), and a gamma-ray spectrometer (GRM; 15-5500 keV) that, together, will characterise the GRB prompt emission spectrum over a wide energy range. In this paper we describe the performances of the ECLAIRs and GRM system with different populations of GRBs from existing catalogues, from the classical ones to those with a possible thermal component superimposed to their non-thermal emission. The combination of ECLAIRs and the GRM will provide new insights also on other GRB properties, as for example the spectral characterisation of the subclass of short GRBs showing an extended emission after the initial spike.

Cosmic ray and neutrino emission from gamma-ray bursts with a nuclear cascade

Science.gov (United States)

Biehl, D.; Boncioli, D.; Fedynitch, A.; Winter, W.

2018-04-01

Aim. We discuss neutrino and cosmic ray emission from gamma-ray bursts (GRBs) with the injection of nuclei, where we take into account that a nuclear cascade from photodisintegration can fully develop in the source. Our main objective is to test whether recent results from the IceCube and the Pierre Auger Observatory can be accommodated within the paradigm that GRBs are the sources of ultra-high-energy cosmic rays (UHECRs). Methods: We simulate this scenario in a combined source-propagation model. While our key results are obtained using an internal shock model of the source, we discuss how the secondary emission from a GRB shell can be interpreted in terms of other astrophysical models. Results: We demonstrate that the expected neutrino flux from GRBs weakly depends on the injection composition for the same injection spectra and luminosities, which implies that prompt neutrinos from GRBs can efficiently test the GRB-UHECR paradigm even if the UHECRs are nuclei. We show that the UHECR spectrum and composition, as measured by the Pierre Auger Observatory, can be self-consistently reproduced. In an attempt to describe the energy range including the ankle, we find tension with the IceCube bounds from the GRB stacking analyses. In an alternative scenario, where only the UHECRs beyond the ankle originate from GRBs, the requirement for a joint description of cosmic ray and neutrino observations favors lower luminosities, which does not correspond to the typical expectation from γ-ray observations.

A LINGERING NON-THERMAL COMPONENT IN THE GAMMA-RAY BURST PROMPT EMISSION: PREDICTING GeV EMISSION FROM THE MeV SPECTRUM

International Nuclear Information System (INIS)

Basak, Rupal; Rao, A. R.

2013-01-01

The high-energy GeV emission of gamma-ray bursts (GRBs) detected by Fermi/LAT has a significantly different morphology compared to the lower energy MeV emission detected by Fermi/GBM. Though the late-time GeV emission is believed to be synchrotron radiation produced via an external shock, this emission as early as the prompt phase is puzzling. A meaningful connection between these two emissions can be drawn only by an accurate description of the prompt MeV spectrum. We perform a time-resolved spectroscopy of the Gamma-ray Burst Monitor (GBM) data of long GRBs with significant GeV emission, using a model consisting of two blackbodies and a power law. We examine in detail the evolution of the spectral components and find that GRBs with high GeV emission (GRB 090902B and GRB 090926A) have a delayed onset of the power-law component in the GBM spectrum, which lingers at the later part of the prompt emission. This behavior mimics the flux evolution in the Large Area Telescope (LAT). In contrast, bright GBM GRBs with an order of magnitude lower GeV emission (GRB 100724B and GRB 091003) show a coupled variability of the total and the power-law flux. Further, by analyzing the data for a set of 17 GRBs, we find a strong correlation between the power-law fluence in the MeV and the LAT fluence (Pearson correlation: r = 0.88 and Spearman correlation: ρ = 0.81). We demonstrate that this correlation is not influenced by the correlation between the total and the power-law fluences at a confidence level of 2.3σ. We speculate the possible radiation mechanisms responsible for the correlation

Correlative Analysis of GRBs detected by Swift and Suzaku-WAM

International Nuclear Information System (INIS)

Krimm, Hans; Yamaoka, Kazutaka; Sugita, Satoshi; Ohno, Masanori; Tashiro, Makoto; Onda, Kaori; Sato, Goro; Sakamoto, Takanori

2008-01-01

Since most gamma-ray bursts (GRBs) have a peak energy (Epeak) above the energy range (15-150 keV) of the Burst Alert Telescope (BAT) on Swift, a full understanding of the prompt emission from Swift GRBs requires spectral fits over as broad an energy range as possible. This can be done for bursts which are simultaneously detected by Swift BAT and the Suzaku Wide-band All-Sky Monitor (WAM), which covers the energy range from 50-5000 keV. Since the launch of Suzaku in July 2005, there have been 33 gamma-ray bursts (GRBs) which have triggered both Swift and WAM. A joint BAT-WAM team has cross-calibrated the two instruments using GRBs, and we are now able to perform joint fits on these bursts to determine spectral parameters including Epeak. The results of broad spectral fits allows us to understand the distribution of Epeak for Swift bursts and to calibrate Epeak estimators when Epeak is within the BAT energy range. For those bursts with spectroscopic redshifts, we can calculate the isotropic energy and study various correlations between Epeak and other global burst parameters. Here we present preliminary results of joint Swift/BAT-Suzaku/WAM spectral fits

Gamma-ray bursts, a puzzle being resolved

CERN Multimedia

Piran, T

1999-01-01

Gamma Ray Bursts (GRBs), short and intense bursts of Gamma-Rays, have puzzled astrophysicists since their accidental discovery in the seventies. BATSE, launched in 1991, has established the cosmological origin of GRBs and has shown that they involve energies much higher than previously expected, corresponding to the most powerful explosions known in the Universe. The fireball model, which has been developed during the last ten years, explains most of the observed features of GRBs . According to this model, GRBs are produced in internal collisions of ejected matter flowing at ultra-relativistic energy. This ultra-relativistic motion reaches Lorentz factors of order 100 or more, higher than seen elsewhere in the Universe. The GRB afterglow was discovered in 1997. It was predicted by this model and it takes place when this relativistic flow is slowed down by the surrounding material. This model was confirmed recently with the discovery last January of the predicted prompt optical emission from GRB 990123. Unfort...

REVISITING THE LONG/SOFT-SHORT/HARD CLASSIFICATION OF GAMMA-RAY BURSTS IN THE FERMI ERA

International Nuclear Information System (INIS)

Zhang Fuwen; Yan Jingzhi; Wei Daming; Shao Lang

2012-01-01

We perform a statistical analysis of the temporal and spectral properties of the latest Fermi gamma-ray bursts (GRBs) to revisit the classification of GRBs. We find that the bimodalities of duration and the energy ratio (E peak /Fluence) and the anti-correlation between spectral hardness (hardness ratio (HR), peak energy, and spectral index) and duration (T 90 ) support the long/soft-short/hard classification scheme for Fermi GRBs. The HR-T 90 anti-correlation strongly depends on the spectral shape of GRBs and energy bands, and the bursts with the curved spectra in the typical BATSE energy bands show a tighter anti-correlation than those with the power-law spectra in the typical BAT energy bands. This might explain why the HR-T 90 correlation is not evident for those GRB samples detected by instruments like Swift with a narrower/softer energy bandpass. We also analyze the intrinsic energy correlation for the GRBs with measured redshifts and well-defined peak energies. The current sample suggests E p,rest = 2455 × (E iso /10 52 ) 0.59 for short GRBs, significantly different from that for long GRBs. However, both the long and short GRBs comply with the same E p,rest -L iso correlation.

Two Early Gamma-ray Bursts Optical Afterglow Detections with TAOS Telescopes--GRB 071010B and GRB 071112C

International Nuclear Information System (INIS)

Huang, K. Y.; Wang, S. Y.; Urata, Y.

2009-01-01

We present on two early detections of GRB afterglows with the Taiwanese-American Occltation Sruvey (TAOS) telescopes. The robotic TAOS system has been devised so that the routine Kuiper Belt Object (KBO) survey is interrupted when a GRB alert is triggered. Our first detection, GRB 071010B was detected by TAOS 62 s after the burst and showed a weak early brightening during the observations. No significant correction with the prompt gamma-ray emission indicated that our optical emission detected is afterglow emission. The second detection of TAOS, GRB 071112C was detected 96 s after the burst, also showed a possible initial raising then followed a steep decay in the R-band light curve.

NEUTRINO EMISSION FROM HIGH-ENERGY COMPONENT GAMMA-RAY BURSTS

International Nuclear Information System (INIS)

Becker, Julia K.; Olivo, Martino; Halzen, Francis; O Murchadha, Aongus

2010-01-01

Gamma-ray bursts (GRBs) have the potential to produce the particle energies (up to 10 21 eV) and energy budget (10 44 erg yr -1 Mpc -3 ) to accommodate the spectrum of the highest energy cosmic rays; on the other hand, there is no observational evidence that they accelerate hadrons. The Fermi Gamma-ray Space Telescope recently observed two bursts that exhibit a power-law high-energy extension of a typical (Band) photon spectrum that extends to ∼30 GeV. On the basis of fireball phenomenology we argue that these two bursts, along with GRB941017 observed by EGRET in 1994, show indirect evidence for considerable baryon loading. Since the detection of neutrinos is the only unambiguous way to establish that GRBs accelerate protons, we use two methods to estimate the neutrino flux produced when they interact with fireball photons to produce charged pions and neutrinos. While the number of events expected from the two Fermi bursts discussed is small, should GRBs be the sources of the observed cosmic rays, a GRB941017-like event that has a hadronic power-law tail extending to several tens of GeV will be detected by the IceCube neutrino telescope.

A Temporal Correlation in Quiescent Gamma-Ray Burst Prompt Emission: Evidence for Prognitor Memory

Science.gov (United States)

Patton, Thomas L.; Giblin, Timothy; Hakkila, Jon E.

2018-06-01

In spite of the insight gained into the nature of the Gamma-Ray Bursts (GRB) from early and late-time X-Ray observations in the Swift era, GRB prompt emission continues to provide clues and new insight into the activity of the central engine. A comprehensive understanding of all emission components observed in GRBs, from the traditional prompt GRB emission to the long lived X-Ray and optical decay super- imposed with late-time flaring activity, currently remains allusive. Using data from the Swift Burst Alert Telescope (BAT), we've identified and measured durations observed in GRBs that exhibit multi-episodic prompt emission behavior. Duration analysis of the burst attributes revealed no significant correlations between emissions and quiet time durations. This variability allows us to extrapolate that the central engine is constantly active.

DUST PROPERTIES IN THE AFTERGLOW OF GRB 071025 AT z {approx} 5

Energy Technology Data Exchange (ETDEWEB)

Jang, Minsung; Im, Myungshin [Center for the Exploration of the Origin of the Universe (CEOU), Astronomy Program, Department of Physics and Astronomy, Seoul National University, Shillim-Dong, Kwanak-Gu, Seoul 151-742 (Korea, Republic of); Lee, Induk; Urata, Yuji [Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan (China); Huang, Kuiyun; Hirashita, Hiroyuki [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Fan Xiaohui; Jiang Linhua, E-mail: msjang.astro@gmail.com, E-mail: mim@astro.snu.ac.kr [Steward Observatory, University of Arizona, Tucson, AZ (United States)

2011-11-15

At high redshift, the universe is so young that core-collapse supernovae (SNe) are suspected to be the dominant source of dust production. However, some observations indicate that the dust production by SNe is an inefficient process, casting doubts on the existence of abundant SNe-dust in the early universe. Recently, Perley et al. reported that the afterglow of GRB 071025-an unusually red gamma-ray burst (GRB) at z {approx} 5-shows evidence for SNe-produced dust. Since this is perhaps the only high-redshift GRB exhibiting compelling evidence for SNe-dust but the result could easily be affected by small systematics in photometry, we re-examined the extinction properties of GRB 071025 using our own optical/near-infrared data at a different epoch. In addition, we tested SNe-dust models with different progenitor masses and dust destruction efficiencies to constrain the dust formation mechanisms. By searching for the best-fit model of the afterglow spectral energy distribution, we confirm the previous claim that the dust in GRB 071025 is most likely to originate from SNe. We also find that the SNe-dust model of 13 or 25 M{sub Sun} without dust destruction fits the extinction property of GRB 071025 best, while pair-instability SNe models with a 170 M{sub Sun} progenitor poorly fit the data. Our results indicate that, at least in some systems at high redshift, SNe with intermediate initial masses within 10-30 M{sub Sun} were the main contributors for the dust enrichment, and the dust destruction effect due to reverse shock was negligible.

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...

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 host...

Significant and variable linear polarization during the prompt optical flash of GRB 160625B.

Science.gov (United States)

Troja, E.; Lipunov, V. M.; Mundell, C. G.; Butler, N. R.; Watson, A. M.; Kobayashi, S.; Cenko, S. B.; Marshall, F. E.; Ricci, R.; Fruchter, A.; Wieringa, M. H.; Gorbovskoy, E. S.; Kornilov, V.; Kutyrev, A.; Lee, W. H.; Toy, V.; Tyurina, N. V.; Budnev, N. M.; Buckley, D. A. H.; González, J.; Gress, O.; Horesh, A.; Panasyuk, M. I.; Prochaska, J. X.; Ramirez-Ruiz, E.; Rebolo Lopez, R.; Richer, M. G.; Roman-Zuniga, C.; Serra-Ricart, M.; Yurkov, V.; Gehrels, N.

2017-07-01

Newly formed black holes of stellar mass launch collimated outflows (jets) of ionized matter that approach the speed of light. These outflows power prompt, brief and intense flashes of γ-rays known as γ-ray bursts (GRBs), followed by longer-lived afterglow radiation that is detected across the electromagnetic spectrum. Measuring the polarization of the observed GRB radiation provides a direct probe of the magnetic fields in the collimated jets. Rapid-response polarimetric observations of newly discovered bursts have probed the initial afterglow phase, and show that, minutes after the prompt emission has ended, the degree of linear polarization can be as high as 30 per cent - consistent with the idea that a stable, globally ordered magnetic field permeates the jet at large distances from the central source. By contrast, optical and γ-ray observations during the prompt phase have led to discordant and often controversial results, and no definitive conclusions have been reached regarding the origin of the prompt radiation or the configuration of the magnetic field. Here we report the detection of substantial (8.3 ± 0.8 per cent from our most conservative simulation), variable linear polarization of a prompt optical flash that accompanied the extremely energetic and long-lived prompt γ-ray emission from GRB 160625B. Our measurements probe the structure of the magnetic field at an early stage of the jet, closer to its central black hole, and show that the prompt phase is produced via fast-cooling synchrotron radiation in a large-scale magnetic field that is advected from the black hole and distorted by dissipation processes within the jet.

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......, whose origin is still unclear. Chandra observations allowed us to localize the X-ray afterglow of GRB 000210 to within approximate to1", and a radio transient was detected with the Very Large Array. The precise X-ray and radio positions allowed us to identify the likely host galaxy of this burst...

Constraints on the bulk Lorentz factor of gamma-ray bursts with the detection rate by Fermi LAT

Science.gov (United States)

Chen, Ye; Liu, Ruo-Yu; Wang, Xiang-Yu

2018-05-01

The bulk Lorentz factor(Γ) of the outflow is an essential parameter to understanding the physics of gamma-ray burst (GRB). Informations about the Lorentz factors of some individual GRBs have been obtained from the spectral features of the high-energy gamma-ray emissions (>100 MeV), assuming that the spectral breaks or cutoffs are due to the pair-production attenuation (i.e., γγ → e+e-). In this paper, we attempt to interpret the dependence of the LAT detection rate of GRBs on the number of high-energy gamma-rays, taking into account the attenuation effect. We first simulate a long-GRB sample with Monte Carlo method using the luminosity function, rate distribution with redshift and properties of the GRB spectrum. To characterize the distribution of the Lorentz factors, we assume that the Lorentz factors follow the relation Γ =Γ _0E_iso,52k, where Eiso, 52 is the isotropic photon energy in unit of 1052erg. After taking into account the attenuation effect related with the above Lorentz factor distribution, we are able to reproduce the LAT-detected rate of GRBs as the function of the number of gamma-rays for suitable choice of the values of Γ0 and k. The result suggests that the distribution of the bulk Lorentz factor for the majority of GRBs is in the range of 50 - 250.

The GRB variability/peak luminosity correlation: new results

International Nuclear Information System (INIS)

Guidorzi, C.; Rossi, F.; Hurley, K.; Mundell, C.G.

2005-01-01

We test the correlation between time variability and isotropic-equivalent peak luminosity found by Reichart et al. (ApJ, 552 (2001) 57) using a set of 26 Gamma-Ray Bursts (GRBs) with known redshift. We confirm the correlation, thought with a larger spread around the best-fit power-law obtained by Reichart et al. which in turn does not provide an acceptable description any longer. In addiction, we find no evidence for correlation between variability and beaming-corrected peak luminosity for a subset of 14 GRBs whose beaming angles have been taken from Ghirlanda et al. (ApJ, 616 (2004) 331). Finally, we investigate the possible connection for some GRBs between the location in the variability/peak luminosity space and some afterglow properties, such as the detectability in the optical band, by adding some GRBs whose redshifts, unknown from direct measurements, have been derived assuming the Amati at al. (AeA, 390 (2002) 81) relationship

A CORRELATED STUDY OF OPTICAL AND X-RAY AFTERGLOWS OF GRBs

Energy Technology Data Exchange (ETDEWEB)

Li, Liang; Ryde, Felix [Department of Physics, KTH Royal Institute of Technology, SE-106 91 Stockholm (Sweden); Wu, Xue-Feng [Chinese Center for Antarctic Astronomy, Chinese Academy of Sciences, Nanjing 210008 (China); Huang, Yong-Feng; Tang, Qing-Wen; Geng, Jin-Jun [Department of Astronomy, Nanjing University, Nanjing 210093, Jiangsu (China); Wang, Xiang-Gao; Liang, En-Wei [GXU-NAOC Center for Astrophysics and Space Sciences, Department of Physics, Guangxi University, Nanjing 530004 (China); Liang, Yun-Feng [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Zhang, Bin-Bin [Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Wang, Yu [Dip. di Fisica and ICRA, Sapienza Universit di Roma, Piazzale Aldo Moro 5, I-00185 Rome (Italy); Wei, Jian-Yan [National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012 (China); Zhang, Bing, E-mail: fryde@kth.se, E-mail: liang.li@fysik.su.se [Department of Physics and Astronomy, University of Nevada, Las Vegas, NV 89154 (United States)

2015-05-20

We study an extensive sample of 87 gamma-ray bursts (GRBs) for which there are well-sampled and simultaneous optical and X-ray light curves. We extract the cleanest possible signal of the afterglow component and compare the temporal behaviors of the X-ray light curve, observed by Swift XRT, and optical data, observed by UVOT and ground-based telescopes for each individual burst. Overall we find that 62% of the GRBs are consistent with the standard afterglow model. When more advanced modeling is invoked, up to 91% of the bursts in our sample may be consistent with the external-shock model. A large fraction of these bursts are consistent with occurring in a constant interstellar density medium (61%) while only 39% of them occur in a wind-like medium. Only nine cases have afterglow light curves that exactly match the standard fireball model prediction, having a single power-law decay in both energy bands that are observed during their entire duration. In particular, for the bursts with chromatic behavior, additional model assumptions must be made over limited segments of the light curves in order for these bursts to fully agree with the external-shock model. Interestingly, for 54% of the X-ray and 40% of the optical band observations, the end of the shallow decay (t{sup ∼−0.5}) period coincides with the jet-break (t{sup ∼−p}) time, causing an abrupt change in decay slope. The fraction of the burst that is consistent with the external-shock model is independent of the observational epochs in the rest frame of GRBs. Moreover, no cases can be explained by the cooling frequency crossing the X-ray or optical band.

GRB 080913 at redshift 6.7

DEFF Research Database (Denmark)

Greiner, J.; Krühler, T.; Fynbo, J. P. U.

2009-01-01

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 ¿ = 9400 Å, and zero flux for 7500 Åinterpret as the onset of a Gunn-Peterson trough at z = 6.695± 0.025 (95.5% confidence level), making GRB 080913 the highest-redshift gamma-ray burst (GRB) to date, and more distant than...

GRB 070610: A Curious Galactic Transient

Science.gov (United States)

Kasliwal, M. M.; Cenko, S. B.; 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. K.; Barthelmy, S.; Cummings, J.; Gehrels, N.; Krimm, H. A.; Markwardt, C. B.; Sato, G.; Chandra, P.; Frail, D.; Fox, D. B.; Price, P. A.; Berger, E.; Grebenev, S. A.; Krivonos, R. A.; Sunyaev, R. A.

2008-05-01

GRB 070610 is a typical high-energy event with a duration of 5 s. 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 timescales even at late times. Using near-infrared imaging assisted by a laser guide star and adaptive optics, we identified the counterpart of Swift J195509.6+261406. Late-time optical and near-infrared imaging constrain the spectral type of the counterpart to be fainter than a K-dwarf, assuming it is of Galactic origin. It is possible that GRB 070610 and Swift J195509.6+261406 are unrelated sources. However, the absence of a typical X-ray afterglow from GRB 070610 in conjunction with the spatial and temporal coincidence of the two motivate us to suggest that the sources are related. The closest (imperfect) 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 subclass of stellar black hole binaries—the fast X-ray novae. We further suggest that fast X-ray novae are associated with bursts of gamma rays. If so, GRB 070610 defines a new class of celestial gamma-ray bursts and these bursts dominate the long-duration GRB demographics.

Observations of Early Optical Afterglows

OpenAIRE

Roming, Peter W. A.; Mason, Keith O.

2006-01-01

The Swift Ultra-Violet/Optical Telescope (UVOT) has performed extensive follow-up on 71 Swift Burst Alert Telescope triggered gamma-ray bursts (GRBs) in its first ten months of operations. In this paper, we discuss some of the UV and optical properties of UVOT detected afterglows such as XRF 050406, the bright GRB 050525A, the high redshift GRB 050730, the early flaring GRB 050801, and others. We also discuss some of the implications of why 75% of GRB afterglows observed by UVOT in less than ...

An apparently normal gamma-ray burst with an unusually low luminosity.

Science.gov (United States)

Sazonov, S Yu; Lutovinov, A A; Sunyaev, R A

2004-08-05

Much of the progress in understanding gamma-ray bursts (GRBs) has come from studies of distant events (redshift z approximately 1). In the brightest GRBs, the gamma-rays are so highly collimated that the events can be seen across the Universe. It has long been suspected that the nearest and most common events have been missed because they are not as collimated or they are under-energetic (or both). Here we report soft gamma-ray observations of GRB 031203, the nearest event to date (z = 0.106; ref. 2). It had a duration of 40 s and peak energy of >190 keV, and therefore appears to be a typical long-duration GRB. The isotropic gamma-ray energy of < or =10(50) erg, however, is about three orders of magnitude smaller than that of the cosmological population. This event--as well as the other nearby but somewhat controversial GRB 980425--is a clear outlier from the isotropic-energy/peak-energy relation and luminosity/spectral-lag relations that describe the majority of GRBs. Radio calorimetry shows that both of these events are under-energetic explosions. We conclude that there does indeed exist a large population of under-energetic events.

The Second Fermi GBM Gamma-Ray Burst Catalog: The First Four Years

NARCIS (Netherlands)

von Kienlin, 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.; Giles, M.; Goldstein, A.; Greiner, J.; Gruber, D.; Guiriec, S.; van der Horst, A.J.; Kouveliotou, C.; Layden, E.; McBreen, S.; McGlynn, S.; Pelassa, V.; Preece, R.D.; Rau, A.; Tierney, D.; Wilson-Hodge, C.A.; Xiong, S.; Younes, G.; Yu, H-F.

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

Resolving The ISM Surrounding GRBs with Afterglow Spectroscopy

International Nuclear Information System (INIS)

Prochaska, J. X.; Chen, H.-W.; Dessauges-Zavadsky, M.; Bloom, J. S.

2008-01-01

We review current research related to spectroscopy of gamma-ray burst (GRB) after-glows with particular emphasis on the interstellar medium (ISM) of the galaxies hosting these high redshift events. These studies reveal the physical conditions of star-forming galaxies and yield clues to the nature of the GRB progenitor. We offer a pedagogical review of the experimental design and review current results. The majority of sightlines are characterized by large HI column densities, negligible molecular fraction, the ubiquitous detection of UV pumped fine-structure transitions, and metallicities ranging from 1/100 to nearly solar abundance

Molecular cloning of the mouse grb2 gene: differential interaction of the Grb2 adaptor protein with epidermal growth factor and nerve growth factor receptors.

OpenAIRE

Suen, K L; Bustelo, X R; Pawson, T; Barbacid, M

1993-01-01

We report the isolation and molecular characterization of the mouse grb2 gene. The product of this gene, the Grb2 protein, is highly related to the Caenorhabditis elegans sem-5 gene product and the human GRB2 protein and displays the same SH3-SH2-SH3 structural motifs. In situ hybridization studies revealed that the mouse grb2 gene is widely expressed throughout embryonic development (E9.5 to P0). However, grb2 transcripts are not uniformly distributed, and in certain tissues (e.g., thymus) t...

GRB 170817A as a jet counterpart to gravitational wave trigger GW 170817

Science.gov (United States)

Lamb, Gavin P.; Kobayashi, Shiho

2018-05-01

Fermi/GBM (Gamma-ray Burst Monitor) and INTEGRAL (the International Gamma-ray Astrophysics Laboratory) reported the detection of the γ-ray counterpart, GRB 170817A, to the LIGO (Light Interferometer Gravitational-wave Observatory)/Virgo gravitational wave detected binary neutron star merger, GW 170817. GRB 170817A is likely to have an internal jet or another origin such as cocoon emission, shock-breakout, or a flare from a viscous disc. In this paper we assume that the γ-ray emission is caused by energy dissipation within a relativistic jet and we model the afterglow synchrotron emission from a reverse- and forward-shock in the outflow. We show the afterglow for a low-luminosity γ-ray burst (GRB) jet with a high Lorentz-factor (Γ); a low-Γ and low-kinetic energy jet; a low-Γ, high kinetic energy jet; structured jets viewed at an inclination within the jet-half-opening angle; and an off-axis `typical' GRB jet. All jet models will produce observable afterglows on various timescales. The late-time afterglow from 10-110 days can be fit by a Gaussian structured jet viewed at a moderate inclination, however the GRB is not directly reproduced by this model. These jet afterglow models can be used for future GW detected NS merger counterparts with a jet afterglow origin.

COSMOLOGICAL IMPLICATIONS OF FAST RADIO BURST/GAMMA-RAY BURST ASSOCIATIONS

Energy Technology Data Exchange (ETDEWEB)

Deng, Wei; Zhang, Bing, E-mail: deng@physics.unlv.edu, E-mail: zhang@physics.unlv.edu [Department of Physics and Astronomy, University of Nevada Las Vegas, Las Vegas, NV 89154 (United States)

2014-03-10

If a small fraction of fast radio bursts (FRBs) are associated with gamma-ray bursts (GRBs), as recently suggested by Zhang, the combination of redshift measurements of GRBs and dispersion measure (DM) measurements of FRBs opens a new window to study cosmology. At z < 2 where the universe is essentially fully ionized, detections of FRB/GRB pairs can give an independent measurement of the intergalactic medium portion of the baryon mass fraction, Ω {sub b} f {sub IGM}, of the universe. If a good sample of FRB/GRB associations are discovered at higher redshifts, the free electron column density history can be mapped, which can be used to probe the reionization history of both hydrogen and helium in the universe. We apply our formulation to GRBs 101011A and 100704A that each might have an associated FRB, and constrained Ω {sub b} f {sub IGM} to be consistent with the value derived from other methods. The methodology developed here is also applicable, if the redshifts of FRBs not associated with GRBs can be measured by other means.

COSMOLOGICAL IMPLICATIONS OF FAST RADIO BURST/GAMMA-RAY BURST ASSOCIATIONS

International Nuclear Information System (INIS)

Deng, Wei; Zhang, Bing

2014-01-01

If a small fraction of fast radio bursts (FRBs) are associated with gamma-ray bursts (GRBs), as recently suggested by Zhang, the combination of redshift measurements of GRBs and dispersion measure (DM) measurements of FRBs opens a new window to study cosmology. At z < 2 where the universe is essentially fully ionized, detections of FRB/GRB pairs can give an independent measurement of the intergalactic medium portion of the baryon mass fraction, Ω b f IGM , of the universe. If a good sample of FRB/GRB associations are discovered at higher redshifts, the free electron column density history can be mapped, which can be used to probe the reionization history of both hydrogen and helium in the universe. We apply our formulation to GRBs 101011A and 100704A that each might have an associated FRB, and constrained Ω b f IGM to be consistent with the value derived from other methods. The methodology developed here is also applicable, if the redshifts of FRBs not associated with GRBs can be measured by other means

Study on corrosion resistance of A106Gr.B and A672Gr.B60 in dynamic water loop with high temperature and pressure

International Nuclear Information System (INIS)

Tian Jue; Wang Hui; Li Xinmin

2014-01-01

Due to the low carbon and low alloy Cr content, flow accelerates corrosion prone to have a serious impact on safety. AP1000 is the most advanced nuclear power technology in recent years. The plant used A672Gr.B60 as an alternative feed pipe to reduce the impact of flow accelerated corrosion. The impact of different flow rates, alkaline agent type and material property on A672Gr.B60 and A106Gr.B were characterized by scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectronic spectroscopy (XPS). After 336 h experiments were conducted, results show that the corrosion rate of A672Gr.B60 is much lower than that of A106Gr.B, and the density of oxidation film on A672Gr.B60 is superior to A106Gr.B. Ethanolamine (ETA) as an alkaline agent is better to reduce FAC to A106Gr.B, and it also can make the oxidation film become denser. Changes in flow rate will affect the size, shape and distribution of the oxide particles, and will also affect the thickness of the oxide film. Both of two materials were composed by Fe 3 O 4 . (authors)

Observational differences between Swift GRB classes

International Nuclear Information System (INIS)

Balazs, L. G.; Horvath, I.; Bagoly, Zs.; Szecsi, D.; Veres, P.

2011-01-01

There are accumulating evidences that GRBs have an intermediate group, beside the short and long classes. Based on the observational data available in the Swift table we compared the observational γ and X ray properties of GRBs making use the discriminant analysis of the multivariate mathematical statistics. The analysis resulted in two canonical discriminating functions giving the maximum separation between the groups. The first discriminating function is dominated by the γ and X-ray fluence while the second one is almost identical with the photon index.

Possible role of gamma ray bursts on life extinction in the universe.

Science.gov (United States)

Piran, Tsvi; Jimenez, Raul

2014-12-05

As a copious source of gamma rays, a nearby galactic gamma ray burst (GRB) can be a threat to life. Using recent determinations of the rate of GRBs, their luminosity function, and properties of their host galaxies, we estimate the probability that a life-threatening (lethal) GRB would take place. Amongst the different kinds of GRBs, long ones are most dangerous. There is a very good chance (but no certainty) that at least one lethal GRB took place during the past 5 gigayears close enough to Earth as to significantly damage life. There is a 50% chance that such a lethal GRB took place during the last 500×10^{6}  years, causing one of the major mass extinction events. Assuming that a similar level of radiation would be lethal to life on other exoplanets hosting life, we explore the potential effects of GRBs to life elsewhere in the Galaxy and the Universe. We find that the probability of a lethal GRB is much larger in the inner Milky Way (95% within a radius of 4 kpc from the galactic center), making it inhospitable to life. Only at the outskirts of the Milky Way, at more than 10 kpc from the galactic center, does this probability drop below 50%. When considering the Universe as a whole, the safest environments for life (similar to the one on Earth) are the lowest density regions in the outskirts of large galaxies, and life can exist in only ≈10% of galaxies. Remarkably, a cosmological constant is essential for such systems to exist. Furthermore, because of both the higher GRB rate and galaxies being smaller, life as it exists on Earth could not take place at z>0.5. Early life forms must have been much more resilient to radiation.

The binary progenitors of short and long GRBs and their gravitational-wave emission

Science.gov (United States)

Rueda, J. A.; Ruffini, R.; Rodriguez, J. F.; Muccino, M.; Aimuratov, Y.; Barres de Almeida, U.; Becerra, L.; Bianco, C. L.; Cherubini, C.; Filippi, S.; Kovacevic, M.; Moradi, R.; Pisani, G. B.; Wang, Y.

2018-01-01

We have sub-classified short and long-duration gamma-ray bursts (GRBs) into seven families according to the binary nature of their progenitors. Short GRBs are produced in mergers of neutron-star binaries (NS-NS) or neutron star-black hole binaries (NS-BH). Long GRBs are produced via the induced gravitational collapse (IGC) scenario occurring in a tight binary system composed of a carbon-oxygen core (COcore) and a NS companion. The COcore explodes as type Ic supernova (SN) leading to a hypercritical accretion process onto the NS: if the accretion is sufficiently high the NS reaches the critical mass and collapses forming a BH, otherwise a massive NS is formed. Therefore long GRBs can lead either to NS-BH or to NS-NS binaries depending on the entity of the accretion. We discuss for the above compact-object binaries: 1) the role of the NS structure and the nuclear equation of state; 2) the occurrence rates obtained from X and gamma-rays observations; 3) the predicted annual number of detections by the Advanced LIGO interferometer of their gravitational-wave emission.

A comprehensive radio view of the extremely bright gamma-ray burst 130427A

NARCIS (Netherlands)

van der Horst, A.J.; Paragi, Z.; de Bruyn, A.G.; Granot, J.; Kouveliotou, C.; Wiersema, K.; Starling, R.L.C.; Curran, P.A.; Wijers, R.A.M.J.; Rowlinson, A.; Anderson, G.A.; Fender, R.P.; Yang, J.; Strom, R.G.

2014-01-01

GRB 130427A was extremely bright as a result of occurring at low redshift whilst the energetics were more typical of high-redshift gamma-ray bursts (GRBs). We collected well-sampled light curves at 1.4 and 4.8 GHz of GRB 130427A with the Westerbork Synthesis Radio Telescope (WSRT); and we obtained

A comprehensive radio view of the extremely bright gamma-ray burst 130427A

NARCIS (Netherlands)

van der Horst, A. J.; Paragi, Z.; de Bruyn, A. G.; Granot, J.; Kouveliotou, C.; Wiersema, K.; Starling, R. L. C.; Curran, P. A.; Wijers, R. A. M. J.; Rowlinson, A.; Anderson, G. A.; Fender, R. P.; Yang, J.; Strom, R. G.

GRB 130427A was extremely bright as a result of occurring at low redshift whilst the energetics were more typical of high-redshift gamma-ray bursts (GRBs). We collected well-sampled light curves at 1.4 and 4.8 GHz of GRB 130427A with the Westerbork Synthesis Radio Telescope (WSRT); and we obtained

Smooth Optical Self-similar Emission of Gamma-Ray Bursts

Energy Technology Data Exchange (ETDEWEB)

Lipunov, Vladimir; Simakov, Sergey; Gorbovskoy, Evgeny; Vlasenko, Daniil, E-mail: lipunov2007@gmail.com [Lomonosov Moscow State University, Sternberg Astronomical Institute, Universitetsky prospect, 13, 119992, Moscow (Russian Federation)

2017-08-10

We offer a new type of calibration for gamma-ray bursts (GRB), in which some class of GRB can be marked and share a common behavior. We name this behavior Smooth Optical Self-similar Emission (SOS-similar Emission) and identify this subclasses of GRBs with optical light curves described by a universal scaling function.

Extending the search for high-energy muon neutrinos from GRBs with ANTARES

CERN Multimedia

2017-01-01

Gamma-ray bursts (GRBs) are transient sources, potential sites of cosmic-rays acceleration: they are expected to produce high-energy neutrinos in pγ interactions through the decay of charged mesons, thus they constitute promising targets for neutrino telescopes. A search for muon neutrinos from GRBs using 9 years of ANTARES data is here presented, assuming particle acceleration at internal shocks, as expected in the fireball model.

Long-term continuous energy injection in the afterglow of GRB 060729

International Nuclear Information System (INIS)

Xu Ming; Huang Yongfeng; Lu Tan

2009-01-01

A long plateau phase and an amazing level of brightness have been observed in the X-ray afterglow of GRB 060729. This peculiar light curve is likely due to long-term energy injection in external shock. Here, we present a detailed numerical study of the energy injection process of magnetic dipole radiation from a strongly magnetized millisecond pulsar and model the multi-band afterglow observations. It is found that this model can successfully explain the long plateaus in the observed X-ray and optical afterglow light curves. The sharp break following the plateaus could be due to the rapid decline of the emission power of the central pulsar. At an even later time (∼ 5 x 10 6 s), an obvious jet break appears, which implies a relatively large half opening angle of θ ∼ 0.3 for the GRB ejecta. Due to the energy injection, the Lorentz factor of the outflow is still larger than two even at 10 7 s after the GRB trigger, making the X-ray afterglow of this burst detectable by Chandra even 642 d after the burst.

Methods and Results of a Search for Gravitational Waves Associated with Gamma-Ray Bursts Using the GEO 600, LIGO, and Virgo Detectors

Science.gov (United States)

Aasi, J.; Abbott, B. P.; Abbott, R.; Abbott, T.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Blackburn, Lindy L.;

Bimodal Long-lasting Components in Short Gamma-Ray Bursts: Promising Electromagnetic Counterparts to Neutron Star Binary Mergers

Energy Technology Data Exchange (ETDEWEB)

Kisaka, Shota; Sakamoto, Takanori [Department of Physics and Mathematics, Aoyama Gakuin University, Sagamihara, Kanagawa, 252-5258 (Japan); Ioka, Kunihito, E-mail: kisaka@phys.aoyama.ac.jp, E-mail: tsakamoto@phys.aoyama.ac.jp, E-mail: kunihito.ioka@yukawa.kyoto-u.ac.jp [Center for Gravitational Physics, Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)

2017-09-10

Long-lasting emission of short gamma-ray bursts (GRBs) is crucial to reveal the physical origin of the central engine as well as to detect electromagnetic (EM) counterparts to gravitational waves (GWs) from neutron star binary mergers. We investigate 65 X-ray light curves of short GRBs, which is six times more than previous studies, by combining both Swift /BAT and XRT data. The light curves are found to consist of two distinct components at >5 σ with bimodal distributions of luminosity and duration, i.e., extended (with a timescale of ≲10{sup 3} s) and plateau emission (with a timescale of ≳10{sup 3} s), which are likely the central engine activities, but not afterglows. The extended emission has an isotropic energy comparable to the prompt emission, while the plateau emission has ∼0.01–1 times this energy. Half (50%) of our sample has both components, while the other half is consistent with having both components. This leads us to conjecture that almost all short GRBs have both the extended and plateau emission. The long-lasting emission can be explained by the jets from black holes with fallback ejecta, and could power macronovae (or kilonovae) like GRB 130603B and GRB 160821B. Based on the observed properties, we quantify the detectability of EM counterparts to GWs, including the plateau emission scattered to the off-axis angle, with CALET /HXM, INTEGRAL /SPI-ACS, Fermi /GBM, MAXI /GSC, Swift /BAT, XRT, the future ISS-Lobster /WFI, Einstein Probe /WXT, and eROSITA .

Spectral Lag Evolution among γ-Ray Burst Pulses Lan-Wei Jia1 ...

Indian Academy of Sciences (India)

pulses with observations by CGRO/BATSE. No universal spectral lag evolution feature and pulse luminosity-lag relation within a GRB is observed. ... Key words. γ-rays: bursts—spectral lag—GRB pulse. 1. Introduction. It is found that soft photons lag behind the hard photons and is usually seen in long. GRBs (e.g., Norris et ...

High energy particles from {gamma}-ray bursts

Energy Technology Data Exchange (ETDEWEB)

Waxman, E [Weizmann Institute of Science, Rehovot (Israel)

2001-11-15

A review is presented of the fireball model of {gamma}-ray bursts (GRBs), and of the production in GRB fireballs of high energy protons and neutrinos. Constraints imposed on the model by recent afterglow observations, which support the association of GRB and ultra-high energy cosmic-ray (UHECR) sources, are discussed. Predictions of the GRB model for UHECR production, which can be tested with planned large area UHECR detectors and with planned high energy neutrino telescopes, are reviewed. (author)

Prompt emission from tidal disruptions of white dwarfs by intermediate mass black holes

Directory of Open Access Journals (Sweden)

Laguna P.

2012-12-01

Full Text Available We present a qualitative picture of prompt emission from tidal disruptions of white dwarfs (WD by intermediate mass black holes (IMBH. The smaller size of an IMBH compared to a supermassive black hole and a smaller tidal radius of a WD disruption lead to a very fast event with high peak luminosity. Magnetic field is generated in situ following the tidal disruption, which leads to effective accretion. Since large-scale magnetic field is also produced, geometrically thick super-Eddington inflow leads to a relativistic jet. The dense jet possesses a photosphere, which emits quasi-thermal radiation in soft X-rays. The source can be classified as a long low-luminosity gamma-ray burst (ll-GRB. Tidal compression of a WD causes nuclear ignition, which is observable as an accompanying supernova. We suggest that GRB060218 and SN2006aj is such a pair of ll-GRB and supernova. We argue that in a flux-limited sample the disruptions of WDs by IMBHs are more frequent then the disruptions of other stars by IMBHs.

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)

Constraining Gamma-ray Burst Initial Lorentz Factor with the Afterglow Onset Feature and Discovery of a Tight Γ0-E γ,iso Correlation

Science.gov (United States)

Liang, En-Wei; Yi, Shuang-Xi; Zhang, Jin; Lü, Hou-Jun; Zhang, Bin-Bin; Zhang, Bing

2010-12-01

The onset of gamma-ray burst (GRB) afterglow is characterized by a smooth bump in the early afterglow light curve as the GRB fireball is decelerated by the circumburst medium. We extensively search for GRBs with such an onset feature in their optical and X-ray light curves from the literature and from the catalog established with the Swift/XRT. Twenty optically selected GRBs and 12 X-ray-selected GRBs are obtained, among which 17 optically selected and 2 X-ray-selected GRBs have redshift measurements. We fit these light curves with a smooth broken power law and measure the width (w), rising timescale (t r), and decaying timescale (t d) at full width at half-maximum. Strong mutual correlations among these timescales and with the peak time (t p) are found. The ratio t r/t d is almost universal among bursts, but the ratio t r/t p varies from 0.3 to ~1. The optical peak luminosity in the R band (L R,p) is anti-correlated with t p and w in the burst frame, indicating a dimmer and broader bump peaking at a later time. The isotropic prompt gamma-ray energy (E γ,iso) is also tightly correlated with L R,p and t p in the burst frame. Assuming that the bumps signal the deceleration of the GRB fireballs in a constant density medium, we calculate the initial Lorentz factor (Γ0) and the deceleration radius (R d) of the GRBs with redshift measurements. The derived Γ0 is typically a few hundreds, and the deceleration radius is R dec ~ 2 × 1017 cm. More intriguingly, a tight correlation between Γ0 and E γ,iso is found, namely Γ0 ~= 182(E γ,iso/1052 erg)0.25. This correlation also applies to the small sample of GRBs which show the signature of the afterglow onset in their X-ray afterglow, and to two bursts (GRBs 990123 and 080319B) whose early optical emission is dominated by a reverse shock. The lower limits of Γ0 derived from a sample of optical afterglow light curves showing a decaying feature from the beginning of the observation are also generally consistent with such

LIMITS ON PROMPT, DISPERSED RADIO PULSES FROM GAMMA-RAY BURSTS

International Nuclear Information System (INIS)

Bannister, K. W.; Murphy, T.; Gaensler, B. M.; Reynolds, J. E.

2012-01-01

We have searched for prompt radio emission from nine gamma-ray bursts (GRBs) with a 12 m telescope at 1.4 GHz, with a time resolution of 64 μs to 1 s. We detected single dispersed radio pulses with significances >6σ in the few minutes following two GRBs. The dispersion measures of both pulses are well in excess of the expected Galactic values, and the implied rate is incompatible with known sources of single dispersed pulses. The arrival times of both pulses also coincide with breaks in the GRB X-ray light curves. A null trial and statistical arguments rule out random fluctuations as the origin of these pulses with >95% and ∼97% confidence, respectively, although a simple population argument supports a GRB origin with confidence of only 2%. We caution that we cannot rule out radio frequency interference (RFI) as the origin of these pulses. If the single pulses are not related to the GRBs, we set an upper limit on the flux density of radio pulses emitted between 200 and 1800 s after a GRB of 1.27w –1/2 Jy, where 6.4 × 10 –5 s –3 s is the pulse width. We set a limit of less than 760 Jy for long timescale (>1 s) variations. These limits are some of the most constraining at high time resolution and GHz frequencies in the early stages of the GRB phenomenon.

The binary progenitors of short and long GRBs and their gravitational-wave emission

Directory of Open Access Journals (Sweden)

Rueda J. A.

2018-01-01

Full Text Available We have sub-classified short and long-duration gamma-ray bursts (GRBs into seven families according to the binary nature of their progenitors. Short GRBs are produced in mergers of neutron-star binaries (NS-NS or neutron star-black hole binaries (NS-BH. Long GRBs are produced via the induced gravitational collapse (IGC scenario occurring in a tight binary system composed of a carbon-oxygen core (COcore and a NS companion. The COcore explodes as type Ic supernova (SN leading to a hypercritical accretion process onto the NS: if the accretion is sufficiently high the NS reaches the critical mass and collapses forming a BH, otherwise a massive NS is formed. Therefore long GRBs can lead either to NS-BH or to NS-NS binaries depending on the entity of the accretion. We discuss for the above compact-object binaries: 1 the role of the NS structure and the nuclear equation of state; 2 the occurrence rates obtained from X and gamma-rays observations; 3 the predicted annual number of detections by the Advanced LIGO interferometer of their gravitational-wave emission.

Photospheric Emission in the Joint GBM and Konus Prompt Spectra of GRB 120323A

Energy Technology Data Exchange (ETDEWEB)

Guiriec, S.; Kouveliotou, C. [Department of Physics, The George Washington University, 725 21st Street NW, Washington, DC 20052 (United States); Gehrels, N.; McEnery, J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Hartmann, D. H., E-mail: sylvain.guiriec@nasa.gov [Department of Physics and Astronomy, Clemson University, Kinard Lab of Physics (United States)

2017-09-10

GRB 120323A is a very intense short gamma -ray burst (GRB) detected simultaneously during its prompt γ -ray emission phase with the Gamma-ray Burst Monitor (GBM) on board the Fermi Gamma-ray Space Telescope and the Konus experiment on board the Wind satellite. GBM and Konus operate in the keV–MeV regime; however, the GBM range is broader toward both the low and the high parts of the γ -ray spectrum. Analyses of such bright events provide a unique opportunity to check the consistency of the data analysis as well as cross-calibrate the two instruments. We performed time-integrated and coarse time-resolved spectral analysis of GRB 120323A prompt emission. We conclude that the analyses of GBM and Konus data are only consistent when using a double-hump spectral shape for both data sets; in contrast, the single hump of the empirical Band function, traditionally used to fit GRB prompt emission spectra, leads to significant discrepancies between GBM and Konus analysis results. Our two-hump model is a combination of a thermal-like and a non-thermal component. We interpret the first component as a natural manifestation of the jet photospheric emission.

The Early Time Properties of GRBs - Canonical Afterglows and the Importance of Prolonged Central Engine Activity

International Nuclear Information System (INIS)

Melandri, A.; Mundell, C. G.; Kobayashi, S.; Bersier, D.; Steele, I. A.; Smith, R. J.; Carter, D.; Bode, M. F.; Guidorzi, C.; Gomboc, A.

2009-01-01

Using a new, comprehensive multiwavelength survey of 63 Gamma Ray Bursts (GRBs) with unprecedented temporal coverage, we classify the observed afterglows into four main classes and discuss the underlying physics that can explain them. The presence or absence of temporal breaks in X-ray and optical bands is used to examine the emission in the context of the standard model; a number of GRBs are shown to deviate from the forward shock model even with the inclusion of energy injection or ambient density gradients. We show that additional emission in the early-time X-ray afterglow due to late-time central engine activity is key and may explain both GRBs whose afterglows do not fit the standard model and those GRBs that appear to be optically dark even at early times.

Three years of Transients with Fermi GBM

Science.gov (United States)

Wilson-Hodge, Colleen A.

2012-01-01

The Gamma-ray Burst Monitor (GBM) is an all-sky monitoring instrument, sensitive between 8 keV and 40 MeV, with a primary objective of supporting the Large Area Telescope (LAT) in observations of Gamma-Ray Bursts (GRBs). Both instruments are part of the Fermi Gamma-ray Space Telescope. Together, the GBM and LAT instruments have provided ground-breaking measurements of GRBs that have, after 10 years of focus on GRB afterglows, inspired renewed interest in the prompt emission phase of GRBs and the physical mechanisms that fuel them. In addition to GRB science, GBM has made significant contributions to the astrophysics of galactic transient sources including long-term variations in the Crab nebula, spin state transitions in accretion powered pulsars, state transitions in black hole X-ray binaries, and unprecedented time-resolved spectral studies of soft gamma-ray repeater bursts. Closer to home, GBM also contributes to solar flare and terrestrial gamma flash science.

Gamma-Ray Burst Afterglows with ALMA

Science.gov (United States)

Urata, Y.; Huang, K.; Takahashi, S.

2015-12-01

We present multi-wavelength observations including sub-millimeter follow-ups for two GRB afterglows. The rapid SMA and multi-wavelength observations for GRB120326A revealed their complex emissions as the synchrotron self-inverse Compton radiation from reverse shock. The observations including ALMA for GRB131030A also showed the significant X-ray excess from the standard forward shock synchrotron model. Based on these results, we also discuss further observations for (A) constraining of the mass of progenitor with polarization, (B) the first confirmation of GRB jet collimation, and (C) revealing the origin of optically dark GRBs.

INVESTIGATION OF PRIMORDIAL BLACK HOLE BURSTS USING INTERPLANETARY NETWORK GAMMA-RAY BURSTS

Energy Technology Data Exchange (ETDEWEB)

Ukwatta, T. N. [Director' s Postdoctoral Fellow, Space and Remote Sensing (ISR-2), Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Hurley, K. [University of California, Berkeley, Space Sciences Laboratory, 7 Gauss Way, Berkeley, CA 94720-7450 (United States); MacGibbon, J. H. [Department of Physics, University of North Florida, Jacksonville, FL 32224 (United States); Svinkin, D. S.; Aptekar, R. L.; Golenetskii, S. V.; Frederiks, D. D.; Pal' shin, V. D. [Ioffe Physical Technical Institute, St. Petersburg, 194021 (Russian Federation); Goldsten, J. [Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723 (United States); Boynton, W. [Department of Planetary Sciences, University of Arizona, Tucson, AZ 85721 (United States); Kozyrev, A. S. [Space Research Institute, 84/32, Profsoyuznaya, Moscow 117997 (Russian Federation); Rau, A.; Kienlin, A. von; Zhang, X. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse, Postfach 1312, Garching, D-85748 (Germany); Connaughton, V. [University of Alabama in Huntsville, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Yamaoka, K. [Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1 Fuchinobe, Sagamihara, Kanagawa 229-8558 (Japan); Ohno, M. [Department of Physics, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Ohmori, N. [Department of Applied Physics, University of Miyazaki, 1-1 Gakuen kibanadai-nishi, Miyazaki-shi, Miyazaki 889-2192 (Japan); Feroci, M. [INAF/IAPS-Roma, via Fosso del Cavaliere 100, I-00133, Roma (Italy); Frontera, F., E-mail: tilan@lanl.gov [Department of Physics and Earth Science, University of Ferrara, via Saragat 1, I-44122 Ferrara (Italy); and others

2016-07-20

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 10{sup 13}–10{sup 18} cm (7–10{sup 5} 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.

Reconstructing the cosmic expansion history up to redshift z=6.29 with the calibrated gamma-ray bursts

International Nuclear Information System (INIS)

Wei, Hao; Nan Zhang, Shuang

2009-01-01

Recently, Gamma-Ray Bursts (GRBs) were proposed to be a complementary cosmological probe to type Ia supernovae (SNIa). GRBs have been advocated to be standard candles since several empirical GRB luminosity relations were proposed as distance indicators. However, there is a so-called circularity problem in the direct use of GRBs. Recently, a new idea to calibrate GRBs in a completely cosmology independent manner has been proposed, and the circularity problem can be solved. In the present work, following the method proposed by Liang et al., we calibrate 70 GRBs with the Amati relation using 307 SNIa. Then, following the method proposed by Shafieloo et al., we smoothly reconstruct the cosmic expansion history up to redshift z=6.29 with the calibrated GRBs. We find some new features in the reconstructed results. (orig.)

Gamma-ray bursts

CERN Document Server

Wijers, Ralph A M J; Woosley, Stan

2012-01-01

Cosmic gamma ray bursts (GRBs) have fascinated scientists and the public alike since their discovery in the late 1960s. Their story is told here by some of the scientists who participated in their discovery and, after many decades of false starts, solved the problem of their origin. Fourteen chapters by active researchers in the field present a detailed history of the discovery, a comprehensive theoretical description of GRB central engine and emission models, a discussion of GRB host galaxies and a guide to how GRBs can be used as cosmological tools. Observations are grouped into three sets from the satellites CGRO, BeppoSAX and Swift, and followed by a discussion of multi-wavelength observations. This is the first edited volume on GRB astrophysics that presents a fully comprehensive review of the subject. Utilizing the latest research, Gamma-ray Bursts is an essential desktop companion for graduate students and researchers in astrophysics.

Wide field x-ray telescopes: Detecting x-ray transients/afterglows related to GRBs

International Nuclear Information System (INIS)

Hudec, Rene; Pina, Ladislav; Inneman, Adolf; Gorenstein, Paul

1998-01-01

The recent discovery of X-ray afterglows of GRBs opens the possibility of analyses of GRBs by their X-ray detections. However, imaging X-ray telescopes in current use mostly have limited fields of view. Alternative X-ray optics geometries achieving very large fields of view have been theoretically suggested in the 70's but not constructed and used so far. We review the geometries and basic properties of the wide-field X-ray optical systems based on one- and two-dimensional lobster-eye geometry and suggest technologies for their development and construction. First results of the development of double replicated X-ray reflecting flats for use in one-dimensional X-ray optics of lobster-eye type are presented and discussed. The optimum strategy for locating GRBs upon their X-ray counterparts is also presented and discussed

Gamma-ray bursts as cosmological probes: ΛCDM vs. conformal gravity

International Nuclear Information System (INIS)

Diaferio, Antonaldo; Ostorero, Luisa; Cardone, Vincenzo

2011-01-01

ΛCDM, for the currently preferred cosmological density Ω 0 and cosmological constant Ω Λ , predicts that the Universe expansion decelerates from early times to redshift z ≈ 0.9 and accelerates at later times. On the contrary, the cosmological model based on conformal gravity predicts that the cosmic expansion has always been accelerating. To distinguish between these two very different cosmologies, we resort to gamma-ray bursts (GRBs), which have been suggested to probe the Universe expansion history at z > 1, where identified type Ia supernovae (SNe) are rare. We use the full Bayesian approach to infer the cosmological parameters and the additional parameters required to describe the GRB data available in the literature. For the first time, we use GRBs as cosmological probes without any prior information from other data. In addition, when we combine the GRB samples with SNe, our approach neatly avoids all the inconsistencies of most numerous previous methods that are plagued by the so-called circularity problem. In fact, when analyzed properly, current data are consistent with distance moduli of GRBs and SNe that can respectively be, in a variant of conformal gravity, ∼ 15 and ∼ 3 magnitudes fainter than in ΛCDM. Our results indicate that the currently available SN and GRB samples are accommodated equally well by both ΛCDM and conformal gravity and do not exclude a continuous accelerated expansion. We conclude that GRBs are currently far from being effective cosmological probes, as they are unable to distinguish between these two very different expansion histories

Gamma-ray Burst Prompt Correlations: Selection and Instrumental Effects

Science.gov (United States)

Dainotti, M. G.; Amati, L.

2018-05-01

The prompt emission mechanism of gamma-ray bursts (GRB) even after several decades remains a mystery. However, it is believed that correlations between observable GRB properties, given their huge luminosity/radiated energy and redshift distribution extending up to at least z ≈ 9, are promising possible cosmological tools. They also may help to discriminate among the most plausible theoretical models. Nowadays, the objective is to make GRBs standard candles, similar to supernovae (SNe) Ia, through well-established and robust correlations. However, differently from SNe Ia, GRBs span over several order of magnitude in their energetics, hence they cannot yet be considered standard candles. Additionally, being observed at very large distances, their physical properties are affected by selection biases, the so-called Malmquist bias or Eddington effect. We describe the state of the art on how GRB prompt correlations are corrected for these selection biases to employ them as redshift estimators and cosmological tools. We stress that only after an appropriate evaluation and correction for these effects, GRB correlations can be used to discriminate among the theoretical models of prompt emission, to estimate the cosmological parameters and to serve as distance indicators via redshift estimation.

THE PROPERTIES OF THE 2175 Å EXTINCTION FEATURE DISCOVERED IN GRB AFTERGLOWS

International Nuclear Information System (INIS)

Zafar, Tayyaba; Watson, Darach; Elíasdóttir, Árdís; Fynbo, Johan P. U.; Krühler, Thomas; Leloudas, Giorgos; Schady, Patricia; Greiner, Jochen; Jakobsson, Páll; Thöne, Christina C.; Perley, Daniel A.; Morgan, Adam N.; Bloom, Joshua

2012-01-01

The unequivocal, spectroscopic detection of the 2175 Å bump in extinction curves outside the Local Group is rare. To date, the properties of the bump have been examined in only two gamma-ray burst (GRB) afterglows (GRB 070802 and GRB 080607). In this work, we analyze in detail the detections of the 2175 Å extinction bump in the optical spectra of two further GRB afterglows: GRB 080605 and 080805. We gather all available optical/near-infrared photometric, spectroscopic, and X-ray data to construct multi-epoch spectral energy distributions (SEDs) for both GRB afterglows. We fit the SEDs with the Fitzpatrick and Massa model with a single or broken power law. We also fit a sample of 38 GRB afterglows, known to prefer a Small Magellanic Cloud (SMC)-type extinction curve, with the same model. We find that the SEDs of GRB 080605 and GRB 080805 at two epochs are fit well with a single power law with a derived extinction of A V = 0.52 +0.13 –0.16 and 0.50 +0.13 –0.10 , and 2.1 +0.7 –0.6 and 1.5 ± 0.2, respectively. While the slope of the extinction curve of GRB 080805 is not well constrained, the extinction curve of GRB 080605 has an unusual very steep far-UV rise together with the 2175 Å bump. Such an extinction curve has previously been found in only a small handful of sightlines in the Milky Way. One possible explanation of such an extinction curve may be dust arising from two different regions with two separate grain populations, however we cannot distinguish the origin of the curve. We finally compare the four 2175 Å bump sightlines to the larger GRB afterglow sample and to Local Group sightlines. We find that while the width and central positions of the bumps are consistent with what is observed in the Local Group, the relative strength of the detected bump (A bump ) for GRB afterglows is weaker for a given A V than for almost any Local Group sightline. Such dilution of the bump strength may offer tentative support to a dual dust-population scenario.

Dimerization in the Grb7 Protein

OpenAIRE

Peterson, Tabitha A.; Benallie, Renee L.; Bradford, Andrew M.; Pias, Sally C.; Yazzie, Jaron.; Lor, Siamee N.; Haulsee, Zachary M.; Park, Chad K.; Johnson, Dennis L.; Rohrschneider, Larry R.; Spuches, Anne.; Lyons, Barbara A.

2012-01-01

In previous studies, we showed that the tyrosine phosphorylation state of growth factor receptor–bound protein 7 (Grb7) affects its ability to bind to the transcription regulator FHL2 and the cortactin-interacting protein, human HS-1-associated protein-1. Here, we present results describing the importance of dimerization in the Grb7–Src homology 2 (SH2) domain in terms of its structural integrity and the ability to bind phosphorylated tyrosine peptide ligands. A tyrosine phosphorylation-mimic...

GRB 030329: 3 years of radio afterglow monitoring

NARCIS (Netherlands)

van der Horst, A.J.; Kamble, A.; Wijers, R.A.M.J.; Resmi, L.; Bhattacharya, D.; Rol, E.; Strom, R.; Kouveliotou, C.; Oosterloo, T.; Ishwara-Chandra, C.H.

2007-01-01

Radio observations of gamma-ray burst (GRB) afterglows are essential for our understanding of the physics of relativistic blast waves, as they enable us to follow the evolution of GRB explosions much longer than the afterglows in any other wave band. We have performed a three-year monitoring

Modeling the Swift BAT Trigger Algorithm with Machine Learning

Science.gov (United States)

Graff, Philip B.; Lien, Amy Y.; 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 et al. (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 approximately greater than 97% (approximately less than 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 eta(sub 0) approximately 0.48(+0.41/-0.23) Gpc(exp -3) yr(exp -1) with power-law indices of eta(sub 1) approximately 1.7(+0.6/-0.5) and eta(sub 2) approximately -5.9(+5.7/-0.1) for GRBs above and below a break point of z(sub 1) approximately 6.8(+2.8/-3.2). This methodology is able to improve upon earlier studies by more accurately modeling Swift detection and using this for fully Bayesian model fitting. The code used in this is analysis is publicly available online.

Gamma-Ray Bursts in Circumstellar Shells: A Possible Explanation for Flares

Science.gov (United States)

Mesler, Robert; Whalen, D. J.; Lloyd-Ronning, N. M.; Fryer, C. L.; Pihlstrom, Y. M.

2012-05-01

It is now generally accepted that long-duration gamma-ray bursts (GRBs) are due to the collapse of massive rotating stars. The precise collapse process itself, however, is not yet fully understood. Strong winds, outbursts, and intense ionizing UV radiation from single stars or strongly interacting binaries are expected to destroy the molecular cloud cores that give birth to them and create highly complex circumburst environments for the explosion. Such environments might imprint features on GRB light curves that uniquely identify the nature of the progenitor and its collapse. We have performed numerical simulations of realistic environments for a variety of long-duration GRB progenitors with ZEUS-MP and have developed an analytical method for calculating detailed GRB light curves in these profiles. We find that, in the context of the standard afterglow model, massive shells around GRBs produce strong signatures in their light curves, and that this clearly distinguishes them from those occurring in uniform media or steady winds. These features can constrain the mass of the shell and the properties of the wind before and after the ejection. Moreover, the interaction of the GRB with the circumburst shell is seen to produce features that are consistent with observed X-ray flares that are often attributed to delayed energy injection by the central engine. Our algorithm for computing light curves is also applicable to GRBs in a variety of environments such as those in high-redshift cosmological halos or protogalaxies, both of which will soon be targets of future surveys such as JANUS or Lobster.

GRB 030227: The first multiwavelength afterglow of an INTEGRAL GRB

DEFF Research Database (Denmark)

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

2003-01-01

We present multiwavelength observations of a gamma-ray burst detected by INTEGRAL (GRB 030227) between 5.3 hours and similar to1.7 days after the event. Here we report the discovery of a dim optical afterglow (OA) that would not have been detected by many previous searches due to its faintess (R ...

Design and implementation of electronics and data acquisition system for Ultra-Fast Flash Observatory

DEFF Research Database (Denmark)

Jung, A.; Ahmad, S.; Barrillon, P.

2013-01-01

. UBAT is equipped with an X-ray detector, analog and digital signal readout electronics that detects X-rays from GRBs and determines the location. SMT is equipped with a stepping motor and the associated electronics to rotate the slewing mirror targeting the GRBs identified by UBAT. First the slewing...... mirror points to a GRB, then SMT obtains the optical image of the GRB using the intensified CCD and its readout electronics. The UFFO Data Acquisition system (UDAQ) is responsible for the overall function and operation of the observatory and the communication with the satellite main processor....... In this paper we present the design and implementation of the electronics of UBAT and SMT as well as the architecture and implementation of UDAQ....

Fermi-LAT Gamma-ray Bursts and Insight from Swift

Science.gov (United States)

Racusin, Judith L.

2011-01-01

A new revolution in GRB observation and theory has begun over the last 3 years since the launch of the Fermi gamma-ray space telescope. The new window into high energy gamma-rays opened by the Fermi-LAT is providing insight into prompt emission mechanisms and possibly also afterglow physics. The LAT detected GRBs appear to be a new unique subset of extremely energetic and bright bursts. In this talk I will discuss the context and recent discoveries from these LAT GRBs and the large database of broadband observations collected by Swift over the last 7 years and how through comparisons between the Swift, GBM, and LAT GRB samples, we can learn about the unique characteristics and relationships between each population.

GRB 051008

DEFF Research Database (Denmark)

Volnova, A. A.; Pozanenko, A. S.; Gorosabel, J.

2014-01-01

due to the presence of a clear, strong Lyman-break feature. The host galaxy is a small starburst galaxy with moderate intrinsic extinction (AV = 0.3) and has a star formation rate of ∼60 M⊙ yr−1 typical for LBGs. It is one of the few cases where a GRB host has been found to be a classical LBG. Using...

The LAGO (Large Aperture GRB Observatory) in Peru

Science.gov (United States)

Tueros-Cuadros, E.; Otiniano, L.; Chirinos, J.; Soncco, C.; Guevara-Day, W.

2012-07-01

The Large Aperture GRBs Observatory is a continental-wide observatory devised to detect high energy (around 100 GeV) component of Gamma Ray Bursts (GRBs), by using the single particle technique in arrays of Water Cherenkov Detectors (WCDs) at high mountain sites of Argentina, Bolivia, Colombia, Guatemala, Mexico, Venezuela and Peru. Details of the instalation and operation of the detectors in Marcapomacocha in Peru at 4550 m.a.s.l. are given. The detector calibration method will also be shown.

ESA Gaia, ultra-low dispersion spectroscopy and GRBs

Czech Academy of Sciences Publication Activity Database

Hudec, René; Šimon, Vojtěch

-, č. 21 (2012), s. 186-189 ISSN 1824-0178. [GRBs as probes from the progenitors environment to the high redshift Universe. Como, 16.05.2011-20.05.2011] R&D Projects: GA ČR GA205/08/1207 Institutional research plan: CEZ:AV0Z10030501 Keywords : gamma-ray bursts * satellites Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

Gamma-ray bursts, QSOs and active galaxies.

Science.gov (United States)

Burbidge, Geoffrey

2007-05-15

The similarity of the absorption spectra of gamma-ray burst (GRB) sources or afterglows with the absorption spectra of quasars (QSOs) suggests that QSOs and GRB sources are very closely related. Since most people believe that the redshifts of QSOs are of cosmological origin, it is natural to assume that GRBs or their afterglows also have cosmological redshifts. For some years a few of us have argued that there is much optical evidence suggesting a very different model for QSOs, in which their redshifts have a non-cosmological origin, and are ejected from low-redshift active galaxies. In this paper I extend these ideas to GRBs. In 2003, Burbidge (Burbidge 2003 Astrophys. J. 183, 112-120) showed that the redshift periodicity in the spectra of QSOs appears in the redshift of GRBs. This in turn means that both the QSOs and the GRB sources are similar objects ejected from comparatively low-redshift active galaxies. It is now clear that many of the GRBs of low redshift do appear in, or very near, active galaxies.A new and powerful result supporting this hypothesis has been produced by Prochter et al. (Prochter et al. 2006 Astrophys. J. Lett. 648, L93-L96). They show that in a survey for strong MgII absorption systems along the sightlines to long-duration GRBs, nearly every sightline shows at least one absorber. If the absorbers are intervening clouds or galaxies, only a small fraction should show absorption of this kind. The number found by Prochter et al. is four times higher than that normally found for the MgII absorption spectra of QSOs. They believe that this result is inconsistent with the intervening hypothesis and would require a statistical fluctuation greater than 99.1% probability. This is what we expect if the absorption is intrinsic to the GRBs and the redshifts are not associated with their distances. In this case, the absorption must be associated with gas ejected from the QSO. This in turn implies that the GRBs actually originate in comparatively low

A Collapsar Model with Disk Wind: Implications for Supernovae Associated with Gamma-Ray Bursts

Science.gov (United States)

Hayakawa, Tomoyasu; Maeda, Keiichi

2018-02-01

We construct a simple but self-consistent collapsar model for gamma-ray bursts (GRBs) and SNe associated with GRBs (GRB-SNe). Our model includes a black hole, an accretion disk, and the envelope surrounding the central system. The evolutions of the different components are connected by the transfer of the mass and angular momentum. To address properties of the jet and the wind-driven SNe, we consider competition of the ram pressure from the infalling envelope and those from the jet and wind. The expected properties of the GRB jet and the wind-driven SN are investigated as a function of the progenitor mass and angular momentum. We find two conditions that should be satisfied if the wind-driven explosion is to explain the properties of the observed GRB-SNe: (1) the wind should be collimated at its base, and (2) it should not prevent further accretion even after the launch of the SN explosion. Under these conditions, some relations seen in the properties of the GRB-SNe could be reproduced by a sequence of different angular momentum in the progenitors. Only the model with the largest angular momentum could explain the observed (energetic) GRB-SNe, and we expect that the collapsar model can result in a wide variety of observational counterparts, mainly depending on the angular momentum of the progenitor star.

Dark-Energy Equation-of-State parameter for high redshifts

International Nuclear Information System (INIS)

Montiel, Ariadna; Breton, Nora

2011-01-01

Since the elucidation of the nature of dark energy depends strongly on redshift observations, it is desirable to measure them over a wider range, but supernovae cannot be detected out past redshift 1.7. Gamma-ray-bursts (GRBs) offer means to extend the analysis to at least redshifts of > 6. The reason is that GRBs are visible across much larger distances than supernovae. GRBs are now known to have several light-curve and spectral properties from which the luminosity of the burst can be calculated, and it might GRBs become into standard candles. We have used data of 69 GRB to study the behavior of the parameter of the dark energy equation of state as a function of redshift.

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

NARCIS (Netherlands)

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

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,

THE THIRD FERMI GBM GAMMA-RAY BURST CATALOG: THE FIRST SIX YEARS

International Nuclear Information System (INIS)

Bhat, P. Narayana; Meegan, Charles A.; Briggs, Michael S.; Burns, Eric; Chaplin, Vandiver; Fitzpatrick, Gerard; Jenke, Peter A.; Von Kienlin, Andreas; Greiner, Jochen; Paciesas, William S.; Cleveland, William H.; Connaughton, Valerie; Burgess, J. Michael; Collazzi, Andrew C.; Diekmann, Anne M.; Gibby, Melissa H.; Giles, Misty M.; Goldstein, Adam M.; Kippen, R. Marc; Kouveliotou, Chryssa

2016-01-01

Since its launch in 2008, the Fermi Gamma-ray Burst Monitor (GBM) has triggered and located on average approximately two γ -ray bursts (GRBs) every three days. Here, we present the third of a series of catalogs of GRBs detected by GBM, extending the second catalog by two more years through the middle of 2014 July. The resulting list includes 1405 triggers identified as 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 derived. The latter two quantities are calculated for the 50–300 keV energy band where the maximum energy release of GRBs in the instrument reference system is observed, and also for a broader energy band from 10 to 1000 keV, exploiting the full energy range of GBM's low-energy [Nai[Tl)] detectors. Using statistical methods to assess clustering, we find that the hardness and duration of GRBs are better fit by a two-component model with short-hard and long-soft bursts than by a model with three components. Furthermore, information is provided on the settings and modifications of the triggering criteria and exceptional operational conditions during years five and six in the mission. This third catalog is an official product of the Fermi GBM science team, and the data files containing the complete results are available from the High-Energy Astrophysics Science Archive Research Center.

THE THIRD FERMI GBM GAMMA-RAY BURST CATALOG: THE FIRST SIX YEARS

Energy Technology Data Exchange (ETDEWEB)

Bhat, P. Narayana; Meegan, Charles A.; Briggs, Michael S.; Burns, Eric; Chaplin, Vandiver; Fitzpatrick, Gerard; Jenke, Peter A. [The Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Von Kienlin, Andreas; Greiner, Jochen [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany); Paciesas, William S.; Cleveland, William H.; Connaughton, Valerie [Universities Space Research Association, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Burgess, J. Michael [The Oskar Klein Centre for Cosmoparticle Physics, AlbaNova, SE-106 91 Stockholm (Sweden); Collazzi, Andrew C. [SciTec Inc., 100 Wall Street, Princeton NJ, 08540 (United States); Diekmann, Anne M.; Gibby, Melissa H.; Giles, Misty M. [Jacobs Technology, Inc., Huntsville, Alabama (United States); Goldstein, Adam M. [ZP12 Astrophysics Office, NASA-Marshall Space Flight Center, Huntsville, AL 35812 (United States); Kippen, R. Marc [Los Alamos National Laboratory, MS B244, P.O. Box 1663, Los Alamos, NM 87545 (United States); Kouveliotou, Chryssa [Department of Physics, The George Washington University, 725 21st Street NW, Washington, DC 20052 (United States); and others

2016-04-01

Since its launch in 2008, the Fermi Gamma-ray Burst Monitor (GBM) has triggered and located on average approximately two γ -ray bursts (GRBs) every three days. Here, we present the third of a series of catalogs of GRBs detected by GBM, extending the second catalog by two more years through the middle of 2014 July. The resulting list includes 1405 triggers identified as 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 derived. The latter two quantities are calculated for the 50–300 keV energy band where the maximum energy release of GRBs in the instrument reference system is observed, and also for a broader energy band from 10 to 1000 keV, exploiting the full energy range of GBM's low-energy [Nai[Tl)] detectors. Using statistical methods to assess clustering, we find that the hardness and duration of GRBs are better fit by a two-component model with short-hard and long-soft bursts than by a model with three components. Furthermore, information is provided on the settings and modifications of the triggering criteria and exceptional operational conditions during years five and six in the mission. This third catalog is an official product of the Fermi GBM science team, and the data files containing the complete results are available from the High-Energy Astrophysics Science Archive Research Center.

CONSTRAINTS ON VERY HIGH ENERGY EMISSION FROM GRB 130427A

International Nuclear Information System (INIS)

Aliu, E.; Errando, M.; Aune, T.; Barnacka, A.; Beilicke, M.; Buckley, J. H.; Bugaev, V.; Benbow, W.; Cerruti, M.; Berger, K.; Biteau, J.; Byrum, K.; Cardenzana, J. V; Dickinson, H. J.; Eisch, J. D.; Chen, X.; Ciupik, L.; Connaughton, V.; Cui, W.; Falcone, A.

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 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

Adaptor protein GRB2 promotes Src tyrosine kinase activation and podosomal organization by protein-tyrosine phosphatase ϵ in osteoclasts.

Science.gov (United States)

Levy-Apter, Einat; Finkelshtein, Eynat; Vemulapalli, Vidyasiri; Li, Shawn S-C; Bedford, Mark T; Elson, Ari

2014-12-26

The non-receptor isoform of protein-tyrosine phosphatase ϵ (cyt-PTPe) supports adhesion of bone-resorbing osteoclasts by activating Src downstream of integrins. Loss of cyt-PTPe reduces Src activity in osteoclasts, reduces resorption of mineralized matrix both in vivo and in cell culture, and induces mild osteopetrosis in young female PTPe KO mice. Activation of Src by cyt-PTPe is dependent upon this phosphatase undergoing phosphorylation at its C-terminal Tyr-638 by partially active Src. To understand how cyt-PTPe activates Src, we screened 73 Src homology 2 (SH2) domains for binding to Tyr(P)-638 of cyt-PTPe. The SH2 domain of GRB2 bound Tyr(P)-638 of cyt-PTPe most prominently, whereas the Src SH2 domain did not bind at all, suggesting that GRB2 may link PTPe with downstream molecules. Further studies indicated that GRB2 is required for activation of Src by cyt-PTPe in osteoclast-like cells (OCLs) in culture. Overexpression of GRB2 in OCLs increased activating phosphorylation of Src at Tyr-416 and of cyt-PTPe at Tyr-638; opposite results were obtained when GRB2 expression was reduced by shRNA or by gene inactivation. Phosphorylation of cyt-PTPe at Tyr-683 and its association with GRB2 are integrin-driven processes in OCLs, and cyt-PTPe undergoes autodephosphorylation at Tyr-683, thus limiting Src activation by integrins. Reduced GRB2 expression also reduced the ability of bone marrow precursors to differentiate into OCLs and reduced the fraction of OCLs in which podosomal adhesion structures assume organization typical of active, resorbing cells. We conclude that GRB2 physically links cyt-PTPe with Src and enables cyt-PTPe to activate Src downstream of activated integrins in OCLs. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Fermi-LAT Gamma-Ray Bursts and Insights from Swift

Science.gov (United States)

Racusin, Judith L.

2010-01-01

A new revolution in Gamma-ray Burst (GRB) observations and theory has begun over the last two years since the launch of the Fermi Gamma-ray Space Telescope. The new window into high energy gamma-rays opened by the Fermi-Large Area Telescope (LAT) is providing insight into prompt emission mechanisms and possibly also afterglow physics. The LAT detected GRBs appear to be a new unique subset of extremely energetic and bright bursts compared to the large sample detected by Swift over the last 6 years. In this talk, I will discuss the context and recent discoveries from these LAT GRBs and the large database of broadband observations collected by the Swift X-ray Telescope (XRT) and UV/Optical Telescope (UVOT). Through comparisons between the GRBs detected by Swift-BAT, G8M, and LAT, we can learn about the unique characteristics, physical differences, and the relationships between each population. These population characteristics provide insight into the different physical parameters that contribute to the diversity of observational GRB properties.

Very Strong TeV Emission as $\\gamma$-Ray Burst Afterglows

CERN Document Server

Totani, T

1998-01-01

Gamma-ray bursts (GRBs) and following afterglows are considered to be produced by dissipation of kinetic energy of a relativistic fireball and radiation process is widely believed as synchrotron radiation or inverse Compton scattering of electrons. We argue that the transfer of kinetic energy of ejecta into electrons may be inefficient process and hence the total energy released by a GRB event is much larger than that emitted in soft gamma-rays, by a factor of \\sim (m_p/m_e). We show that, in this case, very strong emission of TeV gamma-rays is possible due to synchrotron radiation of protons accelerated up to \\sim 10^{21} eV, which are trapped in the magnetic field of afterglow shock and radiate their energy on an observational time scale of \\sim day. This suggests a possibility that GRBs are most energetic in TeV range and such TeV gamma-rays may be detectable from GRBs even at cosmological distances, i.e., z gives a quantitative explanation for the famous long-duration GeV photons detected from GRB940217. ...

Kiso observations of 20 GRBs in the HETE-2 era

International Nuclear Information System (INIS)

Urata, Y.; Tamagawa, T.; Makishima, K.; Tokyo Univ., Tokyo

2005-01-01

We established a GRB follow-up observation system at the Kiso observatory (Japan) in 2001. Since prior to this the east Asian area has been a blank for a GRB follow-up observational network, this observational system is very important for studying the temporal and spectral evolution of early afterglows. We have thus been able to make quick observations of early phase optical afterglows based on HETE-2 and INTEGRAL alerts. Thanks to this quick follow-up observational system, we have so far been able to use the Kiso observatory to monitor 20 events, and conduct follow-up observations in the optical and near-infrared wavelengths

Kiso observations of 20 GRBs in the HETE-2 era

Energy Technology Data Exchange (ETDEWEB)

Urata, Y. [RIKEN, Saitama (Japan); Tokyo Institute of Technology, Tokyo (Japan). Department of Physics; Nakada, Y.; Miyata, T.; Aoki, T.; Soyano, T.; Tarusawa, K.; Mito, H. [Kiso Observatory, Nagano (Japan); Tamagawa, T. [RIKEN, Saitama (Japan); Makishima, K. [RIKEN, Saitama (Japan); Tokyo Univ., Tokyo (Japan). Department of Physics

2005-07-15

We established a GRB follow-up observation system at the Kiso observatory (Japan) in 2001. Since prior to this the east Asian area has been a blank for a GRB follow-up observational network, this observational system is very important for studying the temporal and spectral evolution of early afterglows. We have thus been able to make quick observations of early phase optical afterglows based on HETE-2 and INTEGRAL alerts. Thanks to this quick follow-up observational system, we have so far been able to use the Kiso observatory to monitor 20 events, and conduct follow-up observations in the optical and near-infrared wavelengths.

Go Long, Go Deep: Finding Optical Jet Breaks for Swift-Era GRBs with the LBT

Science.gov (United States)

Dai, X.; Garnavich, P. M.; Prieto, J. L.; Stanek, K. Z.; Kochanek, C. S.; Bechtold, J.; Bouche, N.; Buschkamp, P.; Diolaiti, E.; Fan, X.; Giallongo, E.; Gredel, R.; Hill, J. M.; Jiang, L.; McClelland, C.; Milne, P.; Pedichini, F.; Pogge, R. W.; Ragazzoni, R.; Rhoads, J.; Smareglia, R.; Thompson, D.; Wagner, R. M.

2008-08-01

Using the 8.4 m Large Binocular Telescope, we observed six GRB afterglows from 2.8 hr to 30.8 days after the burst triggers to systematically probe the late-time behaviors of afterglows including jet breaks, flares, and supernova bumps. We detected five afterglows with Sloan r' magnitudes ranging from 23.0 to 26.3 mag. The depth of our observations allows us to extend the temporal baseline for measuring jet breaks by another decade in timescale. We detected two jet breaks and a third candidate, all of which are not detectable without deep, late-time optical observations. In the other three cases, we do not detect the jet breaks either because of contamination from the host galaxy light, the presence of a supernova bump, or the intrinsic faintness of the optical afterglow. This suggests that the basic picture that GRBs are collimated is still valid and that the apparent lack of Swift jet breaks is due to poorly sampled afterglow light curves, particularly at late times. Based on data acquired using the Large Binocular Telescope (LBT). The LBT is an international collaboration among institutions in the United States, Italy, and Germany. LBT Corporation partners are the University of Arizona on behalf of the Arizona university system; Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; the Ohio State University; and the Research Corporation, on behalf of the University of Notre Dame, the University of Minnesota, and the University of Virginia.

Firework Model: Time Dependent Spectral Evolution of GRB

Science.gov (United States)

Barbiellini, Guido; Longo, Francesco; Ghirlanda, G.; Celotti, A.; Bosnjak, Z.

2004-09-01

The energetics of the long duration GRB phenomenon is compared with models of a rotating BH in a strong magnetic field generated by an accreting torus. The GRB energy emission is attributed to magnetic field vacuum breakdown that gives origin to a e +/- fireball. Its subsequent evolution is hypothesized in analogy with the in-flight decay of an elementary particle. An anisotropy in the fireball propagation is thus naturally produced. The recent discovery in some GRB of an initial phase characterized by a thermal spectrum could be interpreted as the photon emission of the fireball photosphere when it becomes transparent. In particular, the temporal evolution of the emission can be explained as the effect of a radiative deceleration of the out-moving ejecta.

The adapter protein, Grb10, is a positive regulator of vascular endothelial growth factor signaling.

Science.gov (United States)

Giorgetti-Peraldi, S; Murdaca, J; Mas, J C; Van Obberghen, E

2001-07-05

Vascular endothelial growth factor (VEGF) is an important regulator of vasculogenesis and angiogenesis. Activation of VEGF receptors leads to the recruitment of SH2 containing proteins which link the receptors to the activation of signaling pathways. Here we report that Grb10, an adapter protein of which the biological role remains unknown, is tyrosine phosphorylated in response to VEGF in endothelial cells (HUVEC) and in 293 cells expressing the VEGF receptor KDR. An intact SH2 domain is required for Grb10 tyrosine phosphorylation in response to VEGF, and this phosphorylation is mediated in part through the activation of Src. In HUVEC, VEGF increases Grb10 mRNA level. Expression of Grb10 in HUVEC or in KDR expressing 293 cells results in an increase in the amount and in the tyrosine phosphorylation of KDR. In 293 cells, this is correlated with the activation of signaling molecules, such as MAP kinase. By expressing mutants of Grb10, we found that the positive action of Grb10 is independent of its SH2 domain. Moreover, these Grb10 effects on KDR seem to be specific since Grb10 has no effect on the insulin receptor, and Grb2, another adapter protein, does not mimic the effect of Grb10 on KDR. In conclusion, we propose that VEGF up-regulates Grb10 level, which in turn increases KDR molecules, suggesting that Grb10 could be involved in a positive feedback loop in VEGF signaling.

Deletion of the Imprinted Gene Grb10 Promotes Hematopoietic Stem Cell Self-Renewal and Regeneration.

Science.gov (United States)

Yan, Xiao; Himburg, Heather A; Pohl, Katherine; Quarmyne, Mamle; Tran, Evelyn; Zhang, Yurun; Fang, Tiancheng; Kan, Jenny; Chao, Nelson J; Zhao, Liman; Doan, Phuong L; Chute, John P

2016-11-01

Imprinted genes are differentially expressed by adult stem cells, but their functions in regulating adult stem cell fate are incompletely understood. Here we show that growth factor receptor-bound protein 10 (Grb10), an imprinted gene, regulates hematopoietic stem cell (HSC) self-renewal and regeneration. Deletion of the maternal allele of Grb10 in mice (Grb10 m/+ mice) substantially increased HSC long-term repopulating capacity, as compared to that of Grb10 +/+ mice. After total body irradiation (TBI), Grb10 m/+ mice demonstrated accelerated HSC regeneration and hematopoietic reconstitution, as compared to Grb10 +/+ mice. Grb10-deficient HSCs displayed increased proliferation after competitive transplantation or TBI, commensurate with upregulation of CDK4 and Cyclin E. Furthermore, the enhanced HSC regeneration observed in Grb10-deficient mice was dependent on activation of the Akt/mTORC1 pathway. This study reveals a function for the imprinted gene Grb10 in regulating HSC self-renewal and regeneration and suggests that the inhibition of Grb10 can promote hematopoietic regeneration in vivo. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Short-hairpin RNA-mediated stable silencing of Grb2 impairs cell growth and DNA synthesis

International Nuclear Information System (INIS)

Di Fulvio, Mauricio; Henkels, Karen M.; Gomez-Cambronero, Julian

2007-01-01

Grb2 is an SH2-SH3 protein adaptor responsible for linking growth factor receptors with intracellular signaling cascades. To study the role of Grb2 in cell growth, we have generated a new COS7 cell line (COS7 shGrb2 ), based on RNAi technology, as null mutations in mammalian Grb2 genes are lethal in early development. This novel cell line continuously expresses a short hairpin RNA that targets endogenous Grb2. Stable COS7 shGrb2 cells had the shGrb2 integrated into the genomic DNA and carried on SiL construct (made refractory to the shRNA-mediated interference), but not with an SH2-deficient mutant (R86K). Thus, a viable knock-down and rescue protocol has demonstrated that Grb2 is crucial for cell proliferation

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

2002-01-01

We report on the results of deep narrow-band Lyalpha and broad-band U and I imaging of the fields of two Gamma-Ray bursts at redshift z = 2.04 (GRB 000301C and GRB 000926). We find that the host galaxy of GRB 000926 is an extended (more than 2 arcsec), strong Lyalpha emitter with a rest-frame equ......We report on the results of deep narrow-band Lyalpha and broad-band U and I imaging of the fields of two Gamma-Ray bursts at redshift z = 2.04 (GRB 000301C and GRB 000926). We find that the host galaxy of GRB 000926 is an extended (more than 2 arcsec), strong Lyalpha emitter with a rest...... - 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...

Mass and metallicity scaling relations of high-redshift star-forming galaxies selected by GRBs

DEFF Research Database (Denmark)

Arabsalmani, M.; Møller, P.; Perley, D.~A.

2018-01-01

-metallicity relation of the general population. It is hard to decide whether this relatively small offset is due to systematic effects or the intrinsic nature of GRB hosts. We also investigate the possibility of using absorption-line metallicity measurements of GRB hosts to study the mass-metallicity relation at high...

Modeling the Swift Bat Trigger Algorithm with Machine Learning

Science.gov (United States)

Graff, Philip B.; Lien, Amy Y.; Baker, John G.; Sakamoto, Takanori

2016-01-01

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 et al. 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 greater than or equal to 97 percent (less than or equal to 3 percent error), which is a significant improvement on a cut in GRB flux, which has an accuracy of 89.6 percent (10.4 percent 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 (sub 0) approaching 0.48 (sup plus 0.41) (sub minus 0.23) per cubic gigaparsecs per year with power-law indices of n (sub 1) approaching 1.7 (sup plus 0.6) (sub minus 0.5) and n (sub 2) approaching minus 5.9 (sup plus 5.7) (sub minus 0.1) for GRBs above and below a break point of z (redshift) (sub 1) approaching 6.8 (sup plus 2.8) (sub minus 3.2). This methodology is able to improve upon earlier studies by more accurately modeling Swift detection and using this for fully Bayesian model fitting.

A new population of ultra-long duration gamma-ray bursts

Energy Technology Data Exchange (ETDEWEB)

Levan, A. J.; Brown, G. C.; Tunnicliffe, R. L. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Tanvir, N. R.; Starling, R. L. C.; Wiersema, K.; Page, K. L.; Wynn, G. A.; O' Brien, P. T. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Perley, D. A. [Department of Astronomy, California Institute of Technology, MC 249-17, 1200 East California Blvd., Pasadena, CA 91125 (United States); Schulze, S. [Pontificia Universidad Católica de Chile, Departamento de Astronomía y Astrofísica, Casilla 306, Santiago 22 (Chile); Chornock, R.; Malesani, D.; Watson, D.; Berger, E. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Hjorth, J. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Københaven Ø (Denmark); Cenko, S. B. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Fruchter, A. S. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD21218 (United States); Jakobsson, P. [Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Dunhagi 5, IS-107 Reykjavk (Iceland); Bersier, D., E-mail: a.j.levan@warwick.ac.uk [Astrophysics Research Institute, Liverpool John Moores University, Egerton Wharf, Birkenhead CH41 1LD (United Kingdom); and others

2014-01-20

We present comprehensive multiwavelength observations of three gamma-ray bursts (GRBs) with durations of several thousand seconds. We demonstrate that these events are extragalactic transients; in particular, we resolve the long-standing conundrum of the distance of GRB 101225A (the 'Christmas-day burst'), finding it to have a redshift z = 0.847 and showing that two apparently similar events (GRB 111209A and GRB 121027A) lie at z = 0.677 and z = 1.773, respectively. The systems show extremely unusual X-ray and optical light curves, very different from classical GRBs, with long-lasting, highly variable X-ray emission and optical light curves that exhibit little correlation with the behavior seen in the X-ray. Their host galaxies are faint, compact, and highly star-forming dwarf galaxies, typical of 'blue compact galaxies'. We propose that these bursts are the prototypes of a hitherto largely unrecognized population of ultra-long GRBs, which while observationally difficult to detect may be astrophysically relatively common. The long durations may naturally be explained by the engine-driven explosions of stars of much larger radii than normally considered for GRB progenitors, which are thought to have compact Wolf-Rayet progenitor stars. However, we cannot unambiguously identify supernova signatures within their light curves or spectra. We also consider the alternative possibility that they arise from the tidal disruption of stars by massive black holes and conclude that the associated timescales are only consistent with the disruption of compact stars (e.g., white dwarfs) by black holes of relatively low mass (<10{sup 5} M {sub ☉}).

The Second SWIFT Burst Alert Telescope (BAT) Gamma-Ray Burst Catalog

Science.gov (United States)

Sakamoto, T.; Barthelmy, S. D.; Baumgartner, W. H.; Cummings, J. R.; Fenimore, E. E.; Gehrels, N.; Krimm, H. A.; Markwardt, C. B.; Palmer, D. M.; Parsons, A. M.;

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

Energy Technology Data Exchange (ETDEWEB)

Yu, Yun-Wei, E-mail: yuyw@mail.ccnu.edu.cn [Institute of Astrophysics, Central China Normal University, Wuhan 430079 (China)

2014-12-01

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.

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

International Nuclear Information System (INIS)

Yu, Yun-Wei

2014-01-01

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.

GRB 130606A AS A PROBE OF THE INTERGALACTIC MEDIUM AND THE INTERSTELLAR MEDIUM IN A STAR-FORMING GALAXY IN THE FIRST Gyr AFTER THE BIG BANG

Energy Technology Data Exchange (ETDEWEB)

Chornock, Ryan; Berger, Edo; Lunnan, Ragnhild; Drout, Maria R.; Fong Wenfai; Laskar, Tanmoy [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Fox, Derek B. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Roth, Katherine C., E-mail: rchornock@cfa.harvard.edu [Gemini Observatory, 670 North Aohoku Place, Hilo, HI 96720 (United States)

2013-09-01

We present high signal-to-noise ratio Gemini and MMT spectroscopy of the optical afterglow of the gamma-ray burst (GRB) 130606A at redshift z = 5.913, discovered by Swift. This is the first high-redshift GRB afterglow to have spectra of comparable quality to those of z Almost-Equal-To 6 quasars. The data exhibit a smooth continuum at near-infrared wavelengths that is sharply cut off blueward of 8410 A due to absorption from Ly{alpha} at redshift z Almost-Equal-To 5.91, with some flux transmitted through the Ly{alpha} forest between 7000 and 7800 A. We use column densities inferred from metal absorption lines to constrain the metallicity of the host galaxy between a lower limit of [Si/H] {approx}> -1.7 and an upper limit of [S/H] {approx}< -0.5 set by the non-detection of S II absorption. We demonstrate consistency between the dramatic evolution in the transmission fraction of Ly{alpha} seen in this spectrum over the redshift range z = 4.9-5.85 with that previously measured from observations of high-redshift quasars. There is an extended redshift interval of {Delta}z = 0.12 in the Ly{alpha} forest at z = 5.77 with no detected transmission, leading to a 3{sigma} upper limit on the mean Ly{alpha} transmission fraction of {approx}<0.2% (or {tau}{sub GP}{sup eff} (Ly{alpha}) > 6.4). This is comparable to the lowest-redshift Gunn-Peterson troughs found in quasar spectra. Some Ly{beta} and Ly{gamma} transmission is detected in this redshift window, indicating that it is not completely opaque, and hence that the intergalactic medium (IGM) is nonetheless mostly ionized at these redshifts. We set a 2{sigma} upper limit of 0.11 on the neutral fraction of the IGM at the redshift of the GRB from the lack of a Ly{alpha} red damping wing, assuming a model with a constant neutral density. GRB 130606A thus for the first time realizes the promise of GRBs as probes of the first galaxies and cosmic reionization.

The High Energy Transient Explorer (HETE): Mission and science overview

International Nuclear Information System (INIS)

Ricker, G.R.; Crew, G.B.; Doty, J.P.; Vanderspek, R.; Villasenor, J.; Atteia, J.-L.; Fenimore, E.E.; Galassi, M.; Graziani, C.; Lamb, D.Q.; Hurley, K.; Jernigan, J.G.; Kawai, N.; Matsuoka, M.; Pizzichini, G.; Shirasaki, Y.; Tamagawa, T.; Vedrenne, G.; Woosley, S.E.; Yoshida, A.

2003-01-01

The High Energy Transient Explorer (HETE ) mission is devoted to the study of gamma-ray bursts (GRBs) using soft X-ray, medium X-ray, and gamma-ray instruments mounted on a compact spacecraft. The HETE satellite was launched into equatorial orbit on 9 October 2000. A science team from France, Japan, Brazil, India, Italy, and the US is responsible for the HETE mission, which was completed for ∼ 1/3 the cost of a NASA Small Explorer (SMEX). The HETE mission is unique in that it is entirely 'self-contained', insofar as it relies upon dedicated tracking, data acquisition, mission operations, and data analysis facilities run by members of its international Science Team. A powerful feature of HETE is its potential for localizing GRBs within seconds of the trigger with good precision (∼ 10') using medium energy X-rays and, for a subset of bright GRBs, improving the localization to ∼ 30''accuracy using low energy X-rays. Real-time GRB localizations are transmitted to ground observers within seconds via a dedicated network of 14 automated 'Burst Alert Stations', thereby allowing prompt optical, IR, and radio follow-up, leading to the identification of counterparts for a large fraction of HETE -localized GRBs. HETE is the only satellite that can provide near-real time localizations of GRBs, and that can localize GRBs that do not have X-ray, optical, and radio afterglows, during the next two years. These capabilities are the key to allowing HETE to probe further the unique physics that produces the brightest known photon sources in the universe. To date (December 2002), HETE has produced 31 GRB localizations. Localization accuracies are routinely in the 4'- 20' range; for the five GRBs with SXC localization, accuracies are ∼1-2'. In addition, HETE has detected ∼ 25 bursts from soft gamma repeaters (SGRs), and >600 X-ray bursts (XRBs)

Unveiling the Progenitors of Short-duration Gamma-ray Bursts

Science.gov (United States)

Fong, Wen-Fai

2016-03-01

Gamma-ray bursts (GRBs) are relativistic explosions which originate at cosmological distances, and are among the most luminous transients in the universe. Following the prompt gamma-ray emission, a fading synchrotron ``afterglow'' is detectable at lower energies. While long-duration GRBs (duration >2 sec) are linked to the deaths of massive stars, the progenitors of short-duration GRBs (duration black hole. Such merging systems are also important to understand because they are premier candidates for gravitational wave detections with current facilities and are likely sites of heavy element nucleosynthesis. The launch of NASA's Swift satellite in 2004, with its rapid multi-wavelength monitoring and localization capabilities, led to the first discoveries of short GRB afterglows and therefore robust associations to host galaxies. At a detection rate of roughly 10 events per year, the growing number of well-localized short GRBs has enabled comprehensive population studies of their afterglows and environments for the first time. In this talk, I describe my multi-wavelength observational campaign to address testable predictions for the progenitors of short GRBs. My work comprises several lines of independent evidence to demonstrate that short GRBs originate from the mergers of two compact objects, and also provides the first constraints on the explosion properties for a large sample of events. With the direct detection of gravitational waves from compact object mergers on the horizon, these studies provide necessary inputs to inform the next decade of joint electromagnetic-gravitational wave search strategies.

The first gamma-ray bursts in the universe

International Nuclear Information System (INIS)

Mesler, R. A.; Pihlström, Y. M.; Whalen, Daniel J.; Smidt, Joseph; Fryer, Chris L.; Lloyd-Ronning, N. M.

2014-01-01

Gamma-ray bursts (GRBs) are the ultimate cosmic lighthouses, capable of illuminating the universe at its earliest epochs. Could such events probe the properties of the first stars at z ∼ 20, the end of the cosmic Dark Ages? Previous studies of Population III (Pop III) GRBs only considered explosions in the diffuse relic H II regions of their progenitors or bursts that are far more energetic than those observed to date. However, the processes that produce GRBs at the highest redshifts likely reset their local environments, creating much more complicated structures than those in which relativistic jets have been modeled so far. These structures can greatly affect the luminosity of the afterglow and hence the redshift at which it can be detected. We have now simulated Pop III GRB afterglows in H II regions, winds, and dense shells ejected by the star during the processes that produce the burst. We find that GRBs with E iso,γ = 10 51 -10 53 erg will be visible at z ≳ 20 to the next generation of near infrared and radio observatories. In many cases, the environment of the burst, and hence progenitor type, can be inferred from the afterglow light curve. Although some Pop III GRBs are visible to Swift and the Very Large Array now, the optimal strategy for their detection will be future missions like the proposed EXIST and JANUS missions with large survey areas and onboard X-ray and infrared telescopes that can track their near-infrared flux from the moment of the burst, thereby identifying their redshifts.

Using GRB 080723B to cross-calibrate Fermi/GBM and INTEGRAL

International Nuclear Information System (INIS)

Kienlin, A. von; Briggs, M. S.; Connoughton, V.; Preece, R. D.; McBreen, S.; Sazonov, Sergey; Tsygankov, Sergey; Wilson-Hodge, C. A.

2009-01-01

On July 23, 2008 GRB 080723B, a bright GRB lasting about 105 s was detected by the INTEGRAL burst alert system. This burst was also detected by the Fermi Gamma-ray burst monitor. At this time no Fermi/GBM GCN notices were distributed to the public because Fermi was still in commissioning phase. The simultaneous detection of a bright GRB by both satellites gives us the opportunity to cross-calibrate the GBM with the already well-calibrated instruments on-board INTEGRAL, the Spectrometer SPI and the Imager IBIS. Time-resolved spectroscopy of this long and structured GRB is of special importance because Fermi was slewing during the GRB was still ongoing. In this paper we present a first and still preliminary analysis of the GBM spectra and compare them to those obtained by SPI for the same selection of time intervals. A more accurate cross-calibration will be forthcoming when the improved in-flight calibration of GBM is available and the corresponding data and responses can be reprocessed.

The prompt to late-time multiwavelength analysis of GRB 060210

NARCIS (Netherlands)

Curran, P.A.; van der Horst, A.J.; Beardmore, A.P.; Page, K.L.; Rol, E.; Melandri, A.; Steele, I.A.; Mundell, C.G.; Gomboc, A.; O'Brien, P.T.; Bersier, D.F.; Bode, M.F.; Carter, D.; Guidorzi, C.; Hill, J.E.; Hurkett, C.P.; Kobayashi, S.; Monfardini, A.; Mottram, C.J.; Smith, R.J.; Wijers, R.A.M.J.; Willingale, R.

2007-01-01

Aims.We present our analysis of the multiwavelength photometric & spectroscopic observations of GRB 060210 and discuss the results in the overall context of current GRB models. Methods: All available optical data underwent a simultaneous temporal fit, while X-ray and gamma-ray observations were

A JET BREAK IN THE X-RAY LIGHT CURVE OF SHORT GRB 111020A: IMPLICATIONS FOR ENERGETICS AND RATES

International Nuclear Information System (INIS)

Fong, W.; Berger, E.; Margutti, R.; Zauderer, B. A.; Czekala, I.; Chornock, R.; Troja, E.; Gehrels, N.; Sakamoto, T.; Fox, D. B.; Podsiadlowski, P.

2012-01-01

We present broadband observations of the afterglow and environment of the short GRB 111020A. An extensive X-ray light curve from Swift/XRT, XMM-Newton, and Chandra, spanning ∼100 s to 10 days after the burst, reveals a significant break at δt ≈ 2 days with pre- and post-break decline rates of α X,1 ≈ –0.78 and α X,2 ∼ j ≈ 3°-8°. The resulting beaming-corrected γ-ray (10-1000 keV band) and blast-wave kinetic energies are (2-3) × 10 48 erg and (0.3-2) × 10 49 erg, respectively, with the range depending on the unknown redshift of the burst. We report a radio afterglow limit of c X , constrains the circumburst density to n 0 ∼ 0.01-0.1 cm –3 . Optical observations provide an afterglow limit of i ∼> 24.4 mag at 18 hr after the burst and reveal a potential host galaxy with i ≈ 24.3 mag. The subarcsecond localization from Chandra provides a precise offset of 0.''80 ± 0.''11 (1σ) from this galaxy corresponding to an offset of 5-7 kpc for z 0.5-1.5. We find a high excess neutral hydrogen column density of (7.5 ± 2.0) × 10 21 cm –2 (z = 0). Our observations demonstrate that a growing fraction of short gamma-ray bursts (GRBs) are collimated, which may lead to a true event rate of ∼> 100-1000 Gpc –3 yr –1 , in good agreement with the NS-NS merger rate of ≈200-3000 Gpc –3 yr –1 . This consistency is promising for coincident short GRB-gravitational wave searches in the forthcoming era of Advanced LIGO/VIRGO.

The blue host galaxy of the red GRB 000418

DEFF Research Database (Denmark)

Gorosabel, J.; Klose, S.; Christensen, L.

2003-01-01

We report on multi-band (UBVRIZJ(s)K(s)) observations of the host galaxy of the April 18, 2000 gamma-ray burst. The Spectral Energy Distribution (SED) is analysed by fitting empirical and synthetic spectral templates. We find that: (i) the best SED fit is obtained with a starburst template, (ii) ...... structures (like dust lanes, spiral arms or disks). A natural scenario which accounts of all the above results is a nuclear starburst that harbours a young population of stars from which the GRB originated....

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

Diverse properties of interstellar medium embedding gamma-ray bursts at the epoch of reionization

International Nuclear Information System (INIS)

Cen, Renyue; Kimm, Taysun

2014-01-01

Analysis is performed on ultra-high-resolution large-scale cosmological radiation-hydrodynamic simulations to quantify, for the first time, the physical environment of long-duration gamma-ray bursts (GRBs) at the epoch of reionization. We find that, on parsec scales, 13% of GRBs remain in high-density (≥10 4 cm –3 ) low-temperature star-forming regions, whereas 87% of GRBs occur in low-density (∼10 –2.5 cm –3 ) high-temperature regions heated by supernovae. More importantly, the spectral properties of GRB afterglows, such as the neutral hydrogen column density, total hydrogen column density, dust column density, gas temperature, and metallicity of intervening absorbers, vary strongly from sight line to sight line. Although our model explains extant limited observationally inferred values with respect to circumburst density, metallicity, column density, and dust properties, a substantially larger sample of high-z GRB afterglows would be required to facilitate a statistically solid test of the model. Our findings indicate that any attempt to infer the physical properties (such as metallicity) of the interstellar medium (ISM) of the host galaxy based on a very small number (usually one) of sight lines would be precarious. Utilizing high-z GRBs to probe the ISM and intergalactic medium should be undertaken properly, taking into consideration the physical diversities of the ISM.

NASA's Swift Education and Public Outreach Program

Science.gov (United States)

Cominsky, L. R.; Graves, T.; Plait, P.; Silva, S.; Simonnet, A.

2004-08-01

Few astronomical objects excite students more than big explosions and black holes. Gamma Ray Bursts (GRBs) are both: powerful explosions that signal the births of black holes. NASA's Swift satellite mission, set for launch in Fall 2004, will detect hundreds of black holes over its two-year nominal mission timeline. The NASA Education and Public Outreach (E/PO) group at Sonoma State University is leading the Swift E/PO effort, using the Swift mission to engage students in science and math learning. We have partnered with the Lawrence Hall of Science to create a ``Great Explorations in Math and Science" guide entitled ``Invisible Universe: from Radio Waves to Gamma Rays," which uses GRBs to introduce students to the electromagnetic spectrum and the scale of energies in the Universe. We have also created new standards-based activities for grades 9-12 using GRBs: one activity puts the students in the place of astronomers 20 years ago, trying to sort out various types of stellar explosions that create high-energy radiation. Another mimics the use of the Interplanetary Network to let students figure out the direction to a GRB. Post-launch materials will include magazine articles about Swift and GRBs, and live updates of GRB information to the Swift E/PO website that will excite and inspire students to learn more about space science.

Gamma-Ray Bursts: Lighting Up the High-Redshift Universe

Science.gov (United States)

Toy, Vicki Louise

Gamma-ray bursts (GRBs) are the most luminous events in the Universe with Egamma,iso ˜ 1048-54 erg. Leading models hypothesize that GRBs are created from inter- nal collisions within collimated and ultrarelativistic jets. The jets then shock-heat the surrounding material (e.g. interstellar medium) to create GRB afterglows. These afterglows are extremely useful probes of the Universe because long GRBs are (1) bright events that can be used as backlights for absorption studies, (2) able to probe at all redshifts massive stars exist, and (3) transient events that allow us to follow- up on the host galaxies at late times. In this thesis we study the environments of GRBs. We first explore the relationship between GRB and supernova (SN) using a nearby GRB-SN (GRB 130702A/SN 2013dx) at z = 0.145. There are only nine other GRB-SNe that were close enough to have extensive spectroscopic and photometric follow-up of the SN at late times. We create a quasi-bolometic light curve of SN 2013dx and fit an analytical equation to the quasi-bolometric light curve combined with measurements of the photospheric velocity to determine SN parameters: mass of 56Ni, kinetic energy, and ejecta mass. We examine the relationship between SN parameters and E gamma,iso for the 10 well-studied GRB-SNe, but find no correlations despite numerical simulation predictions that the mass of 56Ni should correlate with the degree of asymmetry. We then move to larger distance scales and use GRB afterglows as bright back- lights to study distant galaxies. We examine the galactic environments of Damped Lyman-alpha systems (DLAs; NHI ≥ 1020.3 cm-2 ) identified with GRB afterglows at z ˜ 2 - 6. We use late-time photometry after the GRB afterglow has faded to determine star formation rates (SFRs) from rest-frame ultraviolet measurements or spectral energy distribution (SED) models from multiband photometry. We com- pare our sample's SFRs to a sample of quasars (QSOs) DLA host galaxies. Despite the

A Deep Search with the Hubble Space Telescope for Late-Time Supernova Signatures in the Hosts of XRF 011030 and XRF 020427

Science.gov (United States)

Levan, Andrew; Patel, Sandeep; Kouveliotou, Chryssa; Fruchter, Andrew; Rhoads, James; Rol, Evert; Ramirez-Ruiz, Enrico; Gorosabel, Javier; Hiorth, Jens; Wijers, Ralph

2005-01-01

X-ray flashes (XRFs) are, like gamma-ray bursts (GRBs), thought to signal the collapse of massive stars in distant galaxies. Many models posit that the isotropic equivalent energies of XRFs are lower than those for GRBs, such that they are visible fiom a reduced range of distances when compared with GRBs. Here we present the results of two-epoch Hubble Space Telescope imaging of two XRFs. These images, taken approximately 45 and 200 days postburst, reveal no evidence of an associated supernova in either case. Supernovae such as SN 1998bw would have been visible out to z approximately 1.5 in each case, while fainter supernovae such as SN 2002ap would have been visible to z approximately 1. If the XRFs lie at such large distances, their energies would not fit the observed correlation between the GRB peak energy and isotropic energy release (E(sub p) proportional to E(sub iso)(sup 1/2), in which soft bursts are less energetic. We conclude that, should these XRFs reside at low redshifts (z less than 0.6), either their line of sight is heavily extinguished, they are associated with extremely faint supernovae, or, unlike GRBs, these XRFs do not have temporally coincident supernovae.

High energy transients: The millisecond domain

Indian Academy of Sciences (India)

A. R. RAO

2018-02-09

Feb 9, 2018 ... level, the GRB flux distribution is very flat (Fishman &. Meegan 1995)—there are ... the estimated all-sky rate is about one per day (Kumar. & Zhang 2015). ... and the mysterious GRBs possibly signalling the birth of black holes.

Spatially-resolved dust properties of the GRB 980425 host galaxy

DEFF Research Database (Denmark)

Michałowski, Michał J.; Hunt, L. K.; Palazzi, E.

2014-01-01

), located 800 pc away from the GRB position. The host is characterised by low dust content and high fraction of UV-visible star-formation, similar to other dwarf galaxies. Such galaxies are abundant in the local universe, so it is not surprising to find a GRB in one of them, assuming the correspondence...

Solution structure of the human Grb7-SH2 domain/erbB2 peptide complex and structural basis for Grb7 binding to ErbB2

International Nuclear Information System (INIS)

Ivancic, Monika; Daly, Roger J.; Lyons, Barbara A.

2003-01-01

The solution structure of the hGrb7-SH2 domain in complex with a ten amino acid phosphorylated peptide ligand representative of the erbB2 receptor tyrosine kinase (pY1139) is presented as determined by nuclear magnetic resonance methods. The hGrb7-SH2 domain structure reveals the Src homology 2 domain topology consisting of a central β-sheet capped at each end by an α-helix. The presence of a four residue insertion in the region between β-strand E and the EF loop and resulting influences on the SH2 domain/peptide complex structure are discussed. The binding conformation of the erbB2 peptide is in a β-turn similar to that found in phosphorylated tyrosine peptides bound to the Grb2-SH2 domain. To our knowledge this is only the second example of an SH2 domain binding its naturally occurring ligands in a turn, instead of extended, conformation. Close contacts between residues responsible for binding specificity in hGrb7-SH2 and the erbB2 peptide are characterized and the potential effect of mutation of these residues on the hGrb7-SH2 domain structure is discussed

A search for fast radio bursts associated with gamma-ray bursts

International Nuclear Information System (INIS)

Palaniswamy, Divya; Wayth, Randall B.; Trott, Cathryn M.; Tingay, Steven J.; Reynolds, Cormac; McCallum, Jamie N.

2014-01-01

The detection of seven fast radio bursts (FRBs) has recently been reported. FRBs are short duration (∼1 ms), highly dispersed radio pulses from astronomical sources. The physical interpretation for the FRBs remains unclear but is thought to involve highly compact objects at cosmological distance. It has been suggested that a fraction of FRBs could be physically associated with gamma-ray bursts (GRBs). Recent radio observations of GRBs have reported the detection of two highly dispersed short duration radio pulses using a 12 m radio telescope at 1.4 GHz. Motivated by this result, we have performed a systematic and sensitive search for FRBs associated with GRBs. We have observed five GRBs at 2.3 GHz using a 26 m radio telescope located at the Mount Pleasant Radio Observatory, Hobart. The radio telescope was automated to rapidly respond to Gamma-ray Coordination Network notifications from the Swift satellite and slew to the GRB position within ∼140 s. The data were searched for pulses up to 5000 pc cm –3 in dispersion measure and pulse widths ranging from 640 μs to 25.60 ms. We did not detect any events ≥6σ. An in depth statistical analysis of our data shows that events detected above 5σ are consistent with thermal noise fluctuations only. A joint analysis of our data with previous experiments shows that previously claimed detections of FRBs from GRBs are unlikely to be astrophysical. Our results are in line with the lack of consistency noted between the recently presented FRB event rates and GRB event rates.

Predicting supernova associated to gamma-ray burst 130427a

Science.gov (United States)

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

2015-07-01

Binary systems constituted by a neutron star and a massive star are not rare in the universe. The Induced Gravitational Gamma-ray Burst (IGC) paradigm interprets Gamma-ray bursts as the outcome of a neutron star that collapses into a black hole due to the accretion of the ejecta coming from its companion massive star that underwent a supernova event. GRB 130427A is one of the most luminous GRBs ever observed, of which isotropic energy exceeds 1054 erg. And it is within one of the few GRBs obtained optical, X-ray and GeV spectra simultaneously for hundreds of seconds, which provides an unique opportunity so far to understand the multi-wavelength observation within the IGC paradigm, our data analysis found low Lorentz factor blackbody emission in the Episode 3 and its X-ray light curve overlaps typical IGC Golden Sample, which comply to the IGC mechanisms. We consider these findings as clues of GRB 130427A belonging to the IGC GRBs. We predicted on GCN the emergence of a supernova on May 2, 2013, which was later successfully detected on May 13, 2013.

TESTING THE MAGNETAR MODEL VIA LATE-TIME RADIO OBSERVATIONS OF TWO MACRONOVA CANDIDATES

Energy Technology Data Exchange (ETDEWEB)

Horesh, Assaf [Benoziyo Center for Astrophysics, Weizmann Institute of Science, 76100 Rehovot (Israel); Hotokezaka, Kenta; Piran, Tsvi [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel); Nakar, Ehud [Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel); Hancock, Paul [International Centre for Radio Astronomy Research (ICRAR), Curtin University, GPO Box U1987, Perth WA 6845 (Australia)

2016-03-10

Compact binary mergers may have already been observed as they are the leading model for short gamma-ray bursts (sGRBs). Radioactive decay within the ejecta from these mergers is expected to produce an infrared flare, dubbed macronova (or kilonova), on a timescale of a week. Recently, two such macronova candidates were identified in followup observations of sGRBs, strengthening the possibility that those indeed arise from mergers. The same ejecta will also produce long-term (months to years) radio emission due to its interaction with the surrounding interstellar medium. In the search for this emission, we observed the two macronova candidates, GRB 130603B and GRB 060614, with the Jansky Very Large Array (VLA) and the Australia Telescope Compact Array (ATCA). Our observations resulted in null-detections, putting strong upper limits on the kinetic energy and mass of the ejecta. A possible outcome of a merger is a highly magnetized neutron star (a magnetar), which has been suggested as the central engine for GRBs. Such a magnetar will deposit a significant fraction of its energy into the ejecta leading to a brighter radio flare. Our results, therefore, rule out magnetars in these two events.

Looking inside jets: optical polarimetry as a probe of Gamma-Ray Bursts physics

Science.gov (United States)

Kopac, D.; Mundell, C.

2015-07-01

It is broadly accepted that gamma-ray bursts (GRBs) are powered by accretion of matter by black holes, formed during massive stellar collapse, which launch ultra-relativistic, collimated outflows or jets. The nature of the progenitor star, the structure of the jet, and thus the underlying mechanisms that drive the explosion and provide collimation, remain some of the key unanswered questions. To approach these problems, and in particular the role of magnetic fields in GRBs, early time-resolved polarimetry is the key, because it is the only direct probe of the magnetic fields structure. Using novel fast RINGO polarimeter developed for use on the 2-m robotic optical Liverpool Telescope, we have made the first measurements of optical linear polarization of the early optical afterglows of GRBs, finding linear percentage polarization as high as 30% and, for the first time, making time-resolved polarization measurements. I will present the past 8 years of RINGO observations, discuss how the results fit into the GRB theoretical picture, and highlight recent data, in particular high-time resolution multi-colour optical photometry performed during the prompt GRB phase, which also provides some limits on polarization.

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 ...

Investigating a population of infrared-bright gamma-ray burst host galaxies

Science.gov (United States)

Chrimes, Ashley A.; Stanway, Elizabeth R.; Levan, Andrew J.; Davies, Luke J. M.; Angus, Charlotte R.; Greis, Stephanie M. L.

2018-04-01

We identify and explore the properties of an infrared-bright gamma-ray burst (GRB) host population. Candidate hosts are selected by coincidence with sources in WISE, with matching to random coordinates and a false alarm probability analysis showing that the contamination fraction is ˜ 0.5. This methodology has already identified the host galaxy of GRB 080517. We combine survey photometry from Pan-STARRS, SDSS, APASS, 2MASS, GALEX and WISE with our own WHT/ACAM and VLT/X-shooter observations to classify the candidates and identify interlopers. Galaxy SED fitting is performed using MAGPHYS, in addition to stellar template fitting, yielding 13 possible IR-bright hosts. A further 7 candidates are identified from previously published work. We report a candidate host for GRB 061002, previously unidentified as such. The remainder of the galaxies have already been noted as potential hosts. Comparing the IR-bright population properties including redshift z, stellar mass M⋆, star formation rate SFR and V-band attenuation AV to GRB host catalogues in the literature, we find that the infrared-bright population is biased toward low z, high M⋆ and high AV. This naturally arises from their initial selection - local and dusty galaxies are more likely to have the required IR flux to be detected in WISE. We conclude that while IR-bright GRB hosts are not a physically distinct class, they are useful for constraining existing GRB host populations, particularly for long GRBs.

Pulsar-driven Jets In Sne, Grbs, Lmxbs, Ss 433, And The Universe

Science.gov (United States)

Middleditch, John

2011-05-01

The model of pulsar emission through superluminally induced polarization currents, (SLIP), predicts that pulsations produced by such currents at many light cylinder radii by a rotating, magnetized body, will drive pulsations close to the axis of rotation. In SN 1987A, the possible Rosetta Stone for 99% of SNe, GRBs, ms pulsars, and SS 433, such highly collimated (>1 in 10,000) 2.14 ms pulsations, and the similarly collimated jets of particles which they drove, including 1e-6 solar masses with velocities 0.95 c, were responsible for its very early light curve (days 3-20), its "Mystery Spot," observed slightly later (0.5 to 0.3 c, at days 30-50 and after), and still later, in less collimated form, its bipolarity. The axially driven pulsations enforce a toroidal geometry onto all early SNRs, rendering even SNe Ia unsuitable as standard candles. The numbers for Sco X-1's jet are identical, while those for SS 433 are lower (0.26 c), because of the absence of velocity "boosting" via collisions of heavy elements with lighter ones, due to the nearly pure hydrogen content of the supercritical accretion. SLIP also drives positrons from SNe to high energies, possibly accounting for the excess seen by PAMELA at scores of GeV, and predicts that almost all pulsars with very sharp single pulses have been detected because the Earth is in a favored direction where their fluxes diminish only as 1/distance, and this has been verified in the laboratory as well as for the Parkes Multibeam Survey. SLIP also predicts that GRB afterglows will be 100% pulsed at 500 Hz in their proper frame. Finally, SLIP jets from SNe of the first stars may allow galaxies to form without the need for dark matter. This work was supported in part by the Department of Energy through the Los Alamos Directed Research Grant DR20080085.

Molecular targeting of growth factor receptor-bound 2 (Grb2) as an anti-cancer strategy.

Science.gov (United States)

Dharmawardana, Pathirage G; Peruzzi, Benedetta; Giubellino, Alessio; Burke, Terrence R; Bottaro, Donald P

2006-01-01

Growth factor receptor-bound 2 (Grb2) is a ubiquitously expressed adapter protein that provides a critical link between cell surface growth factor receptors and the Ras signaling pathway. As such, it has been implicated in the oncogenesis of several important human malignancies. In addition to this function, research over the last decade has revealed other fundamental roles for Grb2 in cell motility and angiogenesis--processes that also contribute to tumor growth, invasiveness and metastasis. This functional profile makes Grb2 a high priority target for anti-cancer drug development. Knowledge of Grb2 protein structure, its component Src homology domains and their respective structure-function relationships has facilitated the rapid development of sophisticated drug candidates that can penetrate cells, bind Grb2 with high affinity and potently antagonize Grb2 signaling. These novel compounds offer considerable promise in our growing arsenal of rationally designed anti-cancer therapeutics.

METALLICITY IN THE GRB 100316D/SN 2010bh HOST COMPLEX

International Nuclear Information System (INIS)

Levesque, Emily M.; Berger, Edo; Soderberg, Alicia M.; Chornock, Ryan

2011-01-01

The recent long-duration GRB 100316D, associated with supernova SN 2010bh and detected by Swift, is one of the nearest gamma-ray burst (GRB)-supernovae (SNe) ever observed (z = 0.059). This provides us with a unique opportunity to study the explosion environment on ∼kpc scale in relation to the host galaxy complex. Here we present spatially resolved spectrophotometry of the host galaxy, focusing on both the explosion site and the brightest star-forming regions. Using these data, we extract the spatial profiles of the relevant emission features (Hα, Hβ, [O III]λ5007, and [N II]λ6584) and use these profiles to examine variations in metallicity and star formation rate (SFR) as a function of position in the host galaxy. We conclude that GRB 100316D/SN2010bh occurred in a low-metallicity host galaxy, and that the GRB-SN explosion site corresponds to the region with the lowest metallicity and highest SFR sampled by our observations.

Structural basis for the interaction of the adaptor protein grb14 with activated ras.

Directory of Open Access Journals (Sweden)

Rohini Qamra

Full Text Available Grb14, a member of the Grb7-10-14 family of cytoplasmic adaptor proteins, is a tissue-specific negative regulator of insulin signaling. Grb7-10-14 contain several signaling modules, including a Ras-associating (RA domain, a pleckstrin-homology (PH domain, a family-specific BPS (between PH and SH2 region, and a C-terminal Src-homology-2 (SH2 domain. We showed previously that the RA and PH domains, along with the BPS region and SH2 domain, are necessary for downregulation of insulin signaling. Here, we report the crystal structure at 2.4-Å resolution of the Grb14 RA and PH domains in complex with GTP-loaded H-Ras (G12V. The structure reveals that the Grb14 RA and PH domains form an integrated structural unit capable of binding simultaneously to small GTPases and phosphoinositide lipids. The overall mode of binding of the Grb14 RA domain to activated H-Ras is similar to that of the RA domains of RalGDS and Raf1 but with important distinctions. The integrated RA-PH structural unit in Grb7-10-14 is also found in a second adaptor family that includes Rap1-interacting adaptor molecule (RIAM and lamellipodin, proteins involved in actin-cytoskeleton rearrangement. The structure of Grb14 RA-PH in complex with H-Ras represents the first detailed molecular characterization of tandem RA-PH domains bound to a small GTPase and provides insights into the molecular basis for specificity.

RAPID, MACHINE-LEARNED RESOURCE ALLOCATION: APPLICATION TO HIGH-REDSHIFT GAMMA-RAY BURST FOLLOW-UP

Energy Technology Data Exchange (ETDEWEB)

Morgan, A N; Richards, Joseph W; Butler, Nathaniel R; Bloom, Joshua S [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Long, James; Broderick, Tamara [Department of Statistics, University of California, Berkeley, CA 94720-3860 (United States)

2012-02-20

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 event warrants additional follow-up resources. We train RATE GRB-z using a set consisting of 135 Swift bursts with known redshifts, only 18 of which are z > 4. Cross-validated performance metrics on these training data suggest that {approx}56% of high-z bursts can be captured from following up the top 20% of the ranked candidates, and {approx}84% of high-z bursts are identified after following up the top {approx}40% of candidates. We further use the method to rank 200 + Swift bursts with unknown redshifts according to their likelihood of being high-z.

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

NARCIS (Netherlands)

Ackermann, M.; et al., [Unknown; van der Horst, A.J.

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

The Composition of GRB Jets and the ICMART Model

Energy Technology Data Exchange (ETDEWEB)

Zhang, Bing [University of Nevada, Las Vegas; Guo, Fan [Los Alamos National Laboratory

2015-07-16

Models of gamma ray bursts (GRBs) are drawn from observations of light curves, spectra, and spectral evolution. The ICMART (Internal Collision-induced MAgnetic Reconnection & Turbulence) model and some of its features are presented. Increasing evidence points towards Poynting-flux-dominated jets in at least some (even a good fraction of) GRBs. The main emission component (Band) is of a synchrotron emission origin, produced by electrons accelerated in the emission region. The data seem to require that magnetic reconnection in the moderately-high sigma regime is the mechanism to accelerate particles. Extensive numerical simulations are needed to verify physical details of such a model, and some encouraging results have been obtained.

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

VLT/X-Shooter spectroscopy of the afterglow of the Swift GRB 130606A. Chemical abundances and reionisation at z ~ 6

Science.gov (United States)

Hartoog, O. E.; Malesani, D.; Fynbo, J. P. U.; Goto, T.; Krühler, T.; Vreeswijk, P. M.; De Cia, A.; Xu, D.; Møller, P.; Covino, S.; D'Elia, V.; Flores, H.; Goldoni, P.; Hjorth, J.; Jakobsson, P.; Krogager, J.-K.; Kaper, L.; Ledoux, C.; Levan, A. J.; Milvang-Jensen, B.; Sollerman, J.; Sparre, M.; Tagliaferri, G.; Tanvir, N. R.; de Ugarte Postigo, A.; Vergani, S. D.; Wiersema, K.; Datson, J.; Salinas, R.; Mikkelsen, K.; Aghanim, N.

2015-08-01

Context. The reionisation of the Universe is a process that is thought to have ended around z ~ 6, as inferred from spectroscopy of distant bright background sources, such as quasars (QSO) and gamma-ray burst (GRB) afterglows. Furthermore, spectroscopy of a GRB afterglow provides insight in its host galaxy, which is often too dim and distant to study otherwise. Aims: For the Swift GRB 130606A at z = 5.913 we have obtained a high S/N spectrum covering the full optical and near-IR wavelength region at intermediate spectral resolution with VLT/X-Shooter. We aim to measure the degree of ionisation of the intergalactic medium (IGM) between z = 5.02-5.84 and to study the chemical abundance pattern and dust content of its host galaxy. Methods: We estimated the UV continuum of the GRB afterglow using a power-law extrapolation, then measured the flux decrement due to absorption at Lyα,β, and γ wavelength regions. Furthermore, we fitted the shape of the red damping wing of Lyα. The hydrogen and metal absorption lines formed in the host galaxy were fitted with Voigt profiles to obtain column densities. We investigated whether ionisation corrections needed to be applied. Results: Our measurements of the Lyα-forest optical depth are consistent with previous measurements of QSOs, but have a much smaller uncertainty. The analysis of the red damping wing yields a neutral fraction xH i 5.6. GRBs are useful probes of the ionisation state of the IGM in the early Universe, but because of internal scatter we need a larger statistical sample to draw robust conclusions. The high [Si/Fe] in the host can be due to dust depletion, α-element enhancement, or a combination of both. The very high value of [ Al/Fe ] = 2.40 ± 0.78 might be due to a proton capture process and is probably connected to the stellar population history. We estimate the host metallicity to be -1.7 Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the

Ultrahigh energy neutrino afterglows of nearby long duration gamma-ray bursts

Science.gov (United States)

Thomas, Jessymol K.; Moharana, Reetanjali; Razzaque, Soebur

2017-11-01

Detection of ultrahigh energy (UHE, ≳1 PeV ) neutrinos from astrophysical sources will be a major advancement in identifying and understanding the sources of UHE cosmic rays (CRs) in nature. Long duration gamma-ray burst (GRB) blast waves have been considered as potential acceleration sites of UHECRs. These CRs are expected to interact with GRB afterglow photons, which are synchrotron radiation from relativistic electrons coaccelerated with CRs in the blast wave, and naturally produce UHE neutrinos. Fluxes of these neutrinos are uncertain, however, and crucially depend on the observed afterglow modeling. We have selected a sample of 23 long duration GRBs within redshift 0.5 for which adequate electromagnetic afterglow data are available and which could produce high flux of UHE afterglow neutrinos, being nearby. We fit optical, x-ray, and γ -ray afterglow data with an adiabatic blast wave model in a constant density interstellar medium and in a wind environment where the density of the wind decreases as the inverse square of the radius from the center of the GRB. The blast wave model parameters extracted from these fits are then used for calculating UHECR acceleration and p γ interactions to produce UHE neutrino fluxes from these GRBs. We have also explored the detectability of these neutrinos by currently running and upcoming large area neutrino detectors, such as the Pierre Auger Observatory, IceCube Gen-2, and KM3NeT observatories. We find that our realistic flux models from nearby GRBs will be unconstrained in the foreseeable future.

Extending the Search for Muon Neutrinos Coincident with Gamma-Ray Bursts in IceCube Data

Energy Technology Data Exchange (ETDEWEB)

Aartsen, M. G. [Department of Physics, University of Adelaide, Adelaide, 5005 (Australia); Ackermann, M. [DESY, D-15735 Zeuthen (Germany); Adams, J. [Dept. of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch (New Zealand); Aguilar, J. A.; Ansseau, I. [Université Libre de Bruxelles, Science Faculty CP230, B-1050 Brussels (Belgium); Ahlers, M. [Dept. of Physics and Wisconsin IceCube Particle Astrophysics Center, University of Wisconsin, Madison, WI 53706 (United States); Ahrens, M. [Oskar Klein Centre and Dept. of Physics, Stockholm University, SE-10691 Stockholm (Sweden); Samarai, I. Al [Département de Physique Nucléaire et Corpusculaire, Université de Genève, CH-1211 Genève (Switzerland); Altmann, D.; Anton, G. [Erlangen Centre for Astroparticle Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, D-91058 Erlangen (Germany); Andeen, K. [Department of Physics, Marquette University, Milwaukee, WI 53201 (United States); Anderson, T. [Dept. of Physics, Pennsylvania State University, University Park, PA 16802 (United States); Archinger, M.; Baum, V. [Institute of Physics, University of Mainz, Staudinger Weg 7, D-55099 Mainz (Germany); Argüelles, C.; Axani, S. [Dept. of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Auffenberg, J. [III. Physikalisches Institut, RWTH Aachen University, D-52056 Aachen (Germany); Bai, X. [Physics Department, South Dakota School of Mines and Technology, Rapid City, SD 57701 (United States); Barwick, S. W. [Dept. of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Collaboration: IceCube Collaboration; and others

2017-07-10

We present an all-sky search for muon neutrinos produced during the prompt γ -ray emission of 1172 gamma-ray bursts (GRBs) with the IceCube Neutrino Observatory. The detection of these neutrinos would constitute evidence for ultra-high-energy cosmic-ray (UHECR) production in GRBs, as interactions between accelerated protons and the prompt γ -ray field would yield charged pions, which decay to neutrinos. A previously reported search for muon neutrino tracks from northern hemisphere GRBs has been extended to include three additional years of IceCube data. A search for such tracks from southern hemisphere GRBs in five years of IceCube data has been introduced to enhance our sensitivity to the highest energy neutrinos. No significant correlation between neutrino events and observed GRBs is seen in the new data. Combining this result with previous muon neutrino track searches and a search for cascade signature events from all neutrino flavors, we obtain new constraints for single-zone fireball models of GRB neutrino and UHECR production.

Automatic Analysis of Swift-XRT data

Science.gov (United States)

Evans, P. A.; Tyler, L. G.; Beardmore, A. P.; Osborne, J. P.

2008-08-01

The Swift spacecraft detects and autonomously observes ˜100 Gamma Ray Bursts (GRBs) per year, ˜96% of which are detected by the X-ray telescope (XRT). GRBs are accompanied by optical transients and the field of ground-based follow-up of GRBs has expanded significantly over the last few years, with rapid response instruments capable of responding to Swift triggers on timescales of minutes. To make the most efficient use of limited telescope time, follow-up astronomers need accurate positions of GRBs as soon as possible after the trigger. Additionally, information such as the X-ray light curve, is of interest when considering observing strategy. The Swift team at Leicester University have developed techniques to improve the accuracy of the GRB positions available from the XRT, and to produce science-grade X-ray light curves of GRBs. These techniques are fully automated, and are executed as soon as data are available.

A common central engine for long gamma-ray bursts and Type Ib/c supernovae

Science.gov (United States)

Sobacchi, E.; Granot, J.; Bromberg, O.; Sormani, M. C.

2017-11-01

Long-duration, spectrally soft gamma-ray bursts (GRBs) are associated with Type Ic core collapse (CC) supernovae (SNe), and thus arise from the death of massive stars. In the collapsar model, the jet launched by the central engine must bore its way out of the progenitor star before it can produce a GRB. Most of these jets do not break out, and are instead 'choked' inside the star, as the central engine activity time, te, is not long enough. Modelling the long-soft GRB duration distribution assuming a power-law distribution for their central engine activity times, ∝ t_e^{-α } for te > tb, we find a steep distribution (α ∼ 4) and a typical GRB jet breakout time of tb ∼ 60s in the star's frame. The latter suggests the presence of a low-density, extended envelope surrounding the progenitor star, similar to that previously inferred for low-luminosity GRBs. Extrapolating the range of validity of this power law below what is directly observable, to te < tb, by only a factor of ∼4-5 produces enough events to account for all Type Ib/c SNe. Such extrapolation is necessary to avoid fine-tuning the distribution of central engine activity times with the breakout time, which are presumably unrelated. We speculate that central engines launching relativistic jets may operate in all Type Ib/c SNe. In this case, the existence of a common central engine would imply that (i) the jet may significantly contribute to the energy of the SN; (ii) various observational signatures, like the asphericity of the explosion, could be directly related to jet's interaction with the star.

VizieR Online Data Catalog: Short GRBs with Fermi GBM and Swift BAT (Burns+, 2016)

Science.gov (United States)

Burns, E.; Connaughton, V.; Zhang, B.-B.; Lien, A.; Briggs, M. S.; Goldstein, A.; Pelassa, V.; Troja, E.

2018-01-01

Compact binary system mergers are expected to generate gravitational radiation detectable by ground-based interferometers. A subset of these, the merger of a neutron star with another neutron star or a black hole, are also the most popular model for the production of short gamma-ray bursts (GRBs). The Swift Burst Alert Telescope (BAT) and the Fermi Gamma-ray Burst Monitor (GBM) trigger on short GRBs (SGRBs) at rates that reflect their relative sky exposures, with the BAT detecting 10 per year compared to about 45 for GBM. We examine the SGRB populations detected by Swift BAT and Fermi GBM. (4 data files).

Angular Distribution of GRBs

Directory of Open Access Journals (Sweden)

L. G. Balázs

2012-01-01

Full Text Available We studied the complete randomness of the angular distribution of BATSE gamma-ray bursts (GRBs. Based on their durations and peak fluxes, we divided the BATSE sample into 5 subsamples (short1, short2, intermediate, long1, long2 and studied the angular distributions separately. We used three methods to search for non-randomness in the subsamples: Voronoi tesselation, minimal spanning tree, and multifractal spectra. To study any non-randomness in the subsamples we defined 13 test-variables (9 from Voronoi tesselation, 3 from the minimal spanning tree and one from the multifractal spectrum. We made Monte Carlo simulations taking into account the BATSE’s sky-exposure function. We tested therandomness by introducing squared Euclidean distances in the parameter space of the test-variables. We recognized that the short1, short2 groups deviate significantly (99.90%, 99.98% from the fully random case in the distribution of the squared Euclidean distances but this is not true for the long samples. In the intermediate group, the squared Euclidean distances also give significant deviation (98.51%.

Insight into the Selectivity of the G7-18NATE Inhibitor Peptide for the Grb7-SH2 Domain Target.

Science.gov (United States)

Watson, Gabrielle M; Lucas, William A H; Gunzburg, Menachem J; Wilce, Jacqueline A

2017-01-01

Growth factor receptor bound protein 7 (Grb7) is an adaptor protein with established roles in the progression of both breast and pancreatic cancers. Through its C-terminal SH2 domain, Grb7 binds to phosphorylated tyrosine kinases to promote proliferative and migratory signaling. Here, we investigated the molecular basis for the specificity of a Grb7 SH2-domain targeted peptide inhibitor. We identified that arginine 462 in the BC loop is unique to Grb7 compared to Grb2, another SH2 domain bearing protein that shares the same consensus binding motif as Grb7. Using surface plasmon resonance we demonstrated that Grb7-SH2 binding to G7-18NATE is reduced 3.3-fold when the arginine is mutated to the corresponding Grb2 amino acid. The reverse mutation in Grb2-SH2 (serine to arginine), however, was insufficient to restore binding of G7-18NATE to Grb2-SH2. Further, using a microarray, we confirmed that G7-18NATE is specific for Grb7 over a panel of 79 SH2 domains, and identified that leucine at the βD6 position may also be a requirement for Grb7-SH2 binding. This study provides insight into the specificity defining features of Grb7 for the inhibitor molecule G7-18NATE, that will assist in the development of improved Grb7 targeted inhibitors.

Insight into the Selectivity of the G7-18NATE Inhibitor Peptide for the Grb7-SH2 Domain Target

Directory of Open Access Journals (Sweden)

Gabrielle M. Watson

2017-09-01

Full Text Available Growth factor receptor bound protein 7 (Grb7 is an adaptor protein with established roles in the progression of both breast and pancreatic cancers. Through its C-terminal SH2 domain, Grb7 binds to phosphorylated tyrosine kinases to promote proliferative and migratory signaling. Here, we investigated the molecular basis for the specificity of a Grb7 SH2-domain targeted peptide inhibitor. We identified that arginine 462 in the BC loop is unique to Grb7 compared to Grb2, another SH2 domain bearing protein that shares the same consensus binding motif as Grb7. Using surface plasmon resonance we demonstrated that Grb7-SH2 binding to G7-18NATE is reduced 3.3-fold when the arginine is mutated to the corresponding Grb2 amino acid. The reverse mutation in Grb2-SH2 (serine to arginine, however, was insufficient to restore binding of G7-18NATE to Grb2-SH2. Further, using a microarray, we confirmed that G7-18NATE is specific for Grb7 over a panel of 79 SH2 domains, and identified that leucine at the βD6 position may also be a requirement for Grb7-SH2 binding. This study provides insight into the specificity defining features of Grb7 for the inhibitor molecule G7-18NATE, that will assist in the development of improved Grb7 targeted inhibitors.

Insight into the Selectivity of the G7-18NATE Inhibitor Peptide for the Grb7-SH2 Domain Target

Science.gov (United States)

Watson, Gabrielle M.; Lucas, William A. H.; Gunzburg, Menachem J.; Wilce, Jacqueline A.

2017-01-01

Growth factor receptor bound protein 7 (Grb7) is an adaptor protein with established roles in the progression of both breast and pancreatic cancers. Through its C-terminal SH2 domain, Grb7 binds to phosphorylated tyrosine kinases to promote proliferative and migratory signaling. Here, we investigated the molecular basis for the specificity of a Grb7 SH2-domain targeted peptide inhibitor. We identified that arginine 462 in the BC loop is unique to Grb7 compared to Grb2, another SH2 domain bearing protein that shares the same consensus binding motif as Grb7. Using surface plasmon resonance we demonstrated that Grb7-SH2 binding to G7-18NATE is reduced 3.3-fold when the arginine is mutated to the corresponding Grb2 amino acid. The reverse mutation in Grb2-SH2 (serine to arginine), however, was insufficient to restore binding of G7-18NATE to Grb2-SH2. Further, using a microarray, we confirmed that G7-18NATE is specific for Grb7 over a panel of 79 SH2 domains, and identified that leucine at the βD6 position may also be a requirement for Grb7-SH2 binding. This study provides insight into the specificity defining features of Grb7 for the inhibitor molecule G7-18NATE, that will assist in the development of improved Grb7 targeted inhibitors. PMID:29018805

Fusion protein based on Grb2-SH2 domain for cancer therapy

International Nuclear Information System (INIS)

Saito, Yuriko; Furukawa, Takako; Arano, Yasushi; Fujibayashi, Yasuhisa; Saga, Tsuneo

2010-01-01

Research highlights: → Grb2 mediates EGFR signaling through binding to phosphorylate EGFR with SH2 domain. → We generated fusion proteins containing 1 or 2 SH2 domains of Grb2 added with TAT. → The one with 2 SH2 domains (TSSF) interfered ERK phosphorylation. → TSSF significantly delayed the growth of EGFR overexpressing tumor in a mouse model. -- Abstract: Epidermal growth factor receptor (EGFR) is one of the very attractive targets for cancer therapy. In this study, we generated fusion proteins containing one or two Src-homology 2 (SH2) domains of growth factor receptor bound protein 2 (Grb2), which bind to phosphorylated EGFR, added with HIV-1 transactivating transcription for cell membrane penetration (termed TSF and TSSF, respectively). We examined if they can interfere Grb2-mediated signaling pathway and suppress tumor growth as expected from the lack of SH3 domain, which is necessary to intermediate EGFR-Grb2 cell signaling, in the fusion proteins. The transduction efficiency of TSSF was similar to that of TSF, but the binding activity of TSSF to EGFR was higher than that of TSF. Treatment of EGFR-overexpressing cells showed that TSSF decreased p42-ERK phosphorylation, while TSF did not. Both the proteins delayed cell growth but did not induce cell death in culture. TSSF also significantly suppressed tumor growth in vivo under consecutive administration. In conclusion, TSSF showed an ability to inhibit EGFR-Grb2 signaling and could have a potential to treat EGFR-activated cancer.

THE PROMPT, HIGH-RESOLUTION SPECTROSCOPIC VIEW OF THE 'NAKED-EYE' GRB080319B

International Nuclear Information System (INIS)

D'Elia, V.; Fiore, F.; Nicastro, F.; Antonelli, L. A.; Guetta, D.; Perna, R.; Lazzati, D.; Krongold, Y.; Covino, S.; Fugazza, D.; Campana, S.; Chincarini, G.; D'Avanzo, P.; Guidorzi, C.; Molinari, E.; Valle, M. Della; Goldoni, P.; Meurs, E. J. A.; Mirabel, F.; Norci, L.

2009-01-01

GRB080319B reached fifth optical magnitude during the burst prompt emission. Thanks to the Very Large Telescope (VLT)/Ultraviolet and Visual Echelle Spectrograph (UVES) rapid response mode, we observed its afterglow just 8m:30s after the gamma-ray burst (GRB) onset when the magnitude was R ∼ 12. This allowed us to obtain the best signal-to-noise (S/N), high-resolution spectrum of a GRB afterglow ever (S/N per resolution element ∼50). The spectrum is rich of absorption features belonging to the main system at z = 0.937, divided in at least six components spanning a total velocity range of 100 km s -1 . The VLT/UVES observations caught the absorbing gas in a highly excited state, producing the strongest Fe II fine structure lines ever observed in a GRB. A few hours later, the optical depth of these lines was reduced by a factor of 4-20, and the optical/UV flux by a factor of ∼60. This proves that the excitation of the observed fine structure lines is due to 'pumping' by the GRB UV photons. A comparison of the observed ratio between the number of photons absorbed by the excited state and those in the Fe II ground state suggests that the six absorbers are ∼2-6 kpc from the GRB site, with component I ∼ 3 times closer to the GRB site than components III-VI. Component I is characterized also by the lack of Mg I absorption, unlike all other components. This may be both due to a closer distance and a lower density, suggesting a structured interstellar matter in this galaxy complex.

Celebrating 25 years of Syncrude`s Geotechnical Review Board

Energy Technology Data Exchange (ETDEWEB)

McKenna, G.

1998-09-01

An historical review of Syncrude`s Geotechnical Review Board (GRB) was presented, relating some of the successes of the Board over the past 25 years since its establishment. A list of the type of challenges faced by Syncrude where the GRB`s guidance and counselling proved to be critical, is also included. The GRB was established in the 1970s to help Syncrude manage its geotechnical-based risks and to enhance its long-range chances to be successful in oil sands mining. Mining oil sands was breaking new ground back then, consequently, the geotechnical risks were largely unknown and the potential of heavy financial losses were great. Under such circumstances making the right decisions in dealing with geotechnical risks was vital to success. The fact that 25 years later Syncrude is still operating on the basis of those earlier decisions and still relies heavily on the expertise of the Board for recommendations and guidance is a testimony to the value of the GRB to Syncrude`s operations. The GRB`s success is credited to the Board`s world-wide expertise, objectivity, focus on the big issues, risk-based approach and its excellent working partnership with Syncrude employees. Dragline mining and tailings management are the areas that benefited the most from the Board`s involvement, but the Board has been involved in every facet of geotechnical-based risk management. Some of the geotechnical challenges that the GRB has helped Syncrude to overcome include dam construction of muskeg foundation, heavy foundations on gassy and temperature-sensitive soils, coring and testing of gassy/expansive oil sands and haul roads, highwall design utilizing locked sands, winter construction of large fluid retaining embankments and characterization and management of fluid fine tailings. 3 refs., 1 graph, 3 figs.

THE OPTICAL AFTERGLOW AND z = 0.92 EARLY-TYPE HOST GALAXY OF THE SHORT GRB 100117A

International Nuclear Information System (INIS)

Fong, W.; Berger, E.; Chornock, R.; Tanvir, N. R.; Levan, A. J.; Fruchter, A. S.; Graham, J. F.; Cucchiara, A.; Fox, D. B.

2011-01-01

We present the discovery of the optical afterglow and early-type host galaxy of the short-duration GRB 100117A. The faint afterglow is detected 8.3 hr after the burst with r AB = 25.46 ± 0.20 mag. Follow-up optical and near-infrared observations uncover a coincident compact red galaxy, identified as an early-type galaxy at a spectroscopic redshift of z ∼ 0.915 with a mass of ∼3 x 10 10 M sun , an age of ∼1 Gyr, and a luminosity of L B ≅ 0.5 L * . From a possible weak detection of [O II]λ3727 emission at z = 0.915 we infer an upper bound on the star formation rate of ∼0.1 M sun yr -1 , leading to a specific star formation rate of ∼ -1 . Thus, GRB 100117A is only the second short burst to date with a secure early-type host (the other being GRB 050724 at z = 0.257) and it has one of the highest short gamma-ray burst (GRB) redshifts. The offset between the host center and the burst position, 470 ± 310 pc, is the smallest to date. Combined with the old stellar population age, this indicates that the burst likely originated from a progenitor with no significant kick velocity. However, from the brightness of the optical afterglow we infer a relatively low density of n ∼ 3 x 10 -4 ε -3 e,-1 ε -1.75 B,-1 cm -3 . The combination of an optically faint afterglow and host suggests that previous such events may have been missed, thereby potentially biasing the known short GRB host population against z ∼> 1 early-type hosts.

Evaluating the Bulk Lorentz Factors of Outflow Material: Lessons Learned from the Extremely Energetic Outburst GRB 160625B

Energy Technology Data Exchange (ETDEWEB)

Wang, Yuan-Zhu; Wang, Hao; Zhang, Shuai; Liang, Yun-Feng; Jin, Zhi-Ping; He, Hao-Ning; Liao, Neng-Hui; Fan, Yi-Zhong; Wei, Da-Ming, E-mail: liangyf@pmo.ac.cn, E-mail: jin@pmo.ac.cn, E-mail: dmwei@pmo.ac.cn [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Science, Nanjing, 210008 (China)

2017-02-10

GRB 160625B is an extremely bright outburst with well-monitored afterglow emission. The geometry-corrected energy is high, up to ∼5.2 × 10{sup 52} erg or even ∼8 × 10{sup 52} erg, rendering it the most energetic GRB prompt emission recorded so far. We analyzed the time-resolved spectra of the prompt emission and found that in some intervals there were likely thermal-radiation components and the high energy emission was characterized by significant cutoff. The bulk Lorentz factors of the outflow material are estimated accordingly. We found out that the Lorentz factors derived in the thermal-radiation model are consistent with the luminosity-Lorentz factor correlation found in other bursts, as well as in GRB 090902B for the time-resolved thermal-radiation components, while the spectral cutoff model yields much lower Lorentz factors that are in tension with the constraints set by the electron pair Compton scattering process. We then suggest that these spectral cutoffs are more likely related to the particle acceleration process and that one should be careful in estimating the Lorentz factors if the spectrum cuts at a rather low energy (e.g., ∼tens of MeV). The nature of the central engine has also been discussed, and a stellar-mass black hole is favored.

A magnetically driven origin for the low luminosity GRB 170817A associated with GW170817

Science.gov (United States)

Tong, Hao; Yu, Cong; Huang, Lei

2018-06-01

The gamma-ray burst GR170817A associated with GW170817 is subluminous and subenergetic compared with other typical short gamma-ray bursts. It may be due to a relativistic jet viewed off-axis, or a structured jet or cocoon emission. Giant flares from magnetars may possibly be ruled out. However, the luminosity and energetics of GRB 170817A are coincident with those of magnetar giant flares. After the coalescence of a binary neutron star, a hypermassive neutron star may be formed. The hypermassive neutron star may have a magnetar-strength magnetic field. During the collapse of this hypermassive neutron star, magnetic field energy will also be released. This giant-flare-like event may explain the luminosity and energetics of GRB 170817A. Bursts with similar luminosity and energetics are expected in future neutron star-neutron star or neutron star-black hole mergers.

Evolution of the color indices in SN 2006aj associated with GRB 060218

Czech Academy of Sciences Publication Activity Database

Šimon, Vojtěch; Pizzichini, G.; Hudec, René

2010-01-01

Roč. 523, Nov-Dec (2010), A56/1-A56/11 ISSN 0004-6361 R&D Projects: GA ČR GA205/08/1207 Grant - others:ESA(XE) ESA-PECS project No. 98058 Institutional research plan: CEZ:AV0Z10030501 Keywords : gamma-ray burst * radiation mechanisms Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.410, year: 2010

A cannonball model of gamma-ray bursts superluminal signatures

CERN Document Server

Dar, Arnon; Dar, Arnon; Rujula, Alvaro De

2000-01-01

Recent observations suggest that the long-duration gamma ray bursts (GRBs) and their afterglows are produced by highly relativistic jets emitted in supernova explosions. We propose that the result of the event is not just a compact object plus the ejecta: within a day, a fraction of the parent star falls back to produce a thick accretion disk. The subsequent accretion generates jets and constitutes the GRB ``engine'', as in the observed ejection of relativistic ``cannonballs'' of plasma by microquasars and active galactic nuclei. The GRB is produced as the jetted cannonballs exit the supernova shell reheated by the collision, re-emitting their own radiation and boosting the light of the shell. They decelerate by sweeping up interstellar matter, which is accelerated to cosmic-ray energies and emits synchrotron radiation: the afterglow. We emphasize here a smoking-gun signature of this model of GRBs: the superluminal motion of the afterglow, that can be searched for ---the sooner the better--- in the particular...

Collapsing supra-massive magnetars: FRBs, the repeating FRB121102 and GRBs

Science.gov (United States)

Gupta, Patrick Das; Saini, Nidhi

2018-02-01

Fast Radio Bursts (FRBs) last for ˜ few milli-seconds and, hence, are likely to arise from the gravitational collapse of supra-massive, spinning neutron stars after they lose the centrifugal support (Falcke & Rezzolla 2014). In this paper, we provide arguments to show that the repeating burst, FRB 121102, can also be modeled in the collapse framework provided the supra-massive object implodes either into a Kerr black hole surrounded by highly magnetized plasma or into a strange quark star. Since the estimated rates of FRBs and SN Ib/c are comparable, we put forward a common progenitor scenario for FRBs and long GRBs in which only those compact remnants entail prompt γ -emission whose kick velocities are almost aligned or anti-aligned with the stellar spin axes. In such a scenario, emission of detectable gravitational radiation and, possibly, of neutrinos are expected to occur during the SN Ib/c explosion as well as, later, at the time of magnetar implosion.

Fast Radio Burst/Gamma-Ray Burst Cosmography

Science.gov (United States)

Gao, He; Li, Zhuo; Zhang, Bing

2014-06-01

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 DM_{IGM} 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 \\lt {DM_IGM} (z)\\gt and luminosity distance (D L(z)) is insensitive to dark energy models. This gives the prospect of applying SN Ia data to calibrate \\lt {DM_IGM} (z)\\gt 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.

Fast radio burst/gamma-ray burst cosmography

International Nuclear Information System (INIS)

Gao, He; Zhang, Bing; Li, Zhuo

2014-01-01

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 DM IGM 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.

Fast radio burst/gamma-ray burst cosmography

Energy Technology Data Exchange (ETDEWEB)

Gao, He; Zhang, Bing [Department of Physics and Astronomy, University of Nevada Las Vegas, NV 89154 (United States); Li, Zhuo, E-mail: gaohe@physics.unlv.edu, E-mail: zhang@physics.unlv.edu, E-mail: zhuo.li@pku.edu.cn [Department of Astronomy, School of Physics, Peking University, Beijing 100871 (China)

2014-06-20

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 DM{sub IGM} 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 {sub 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.

Cosmic gamma-ray bursts from BATSE - Another great debate

Science.gov (United States)

Hartmann, Dieter H.; The, Lih-Sin; Clayton, Donald D.; Schnepf, Neil G.; Linder, Eric V.

1992-01-01

The BATSE detectors aboard Compton Observatory record about one cosmic gamma-ray burst (GRB) per day. Preliminary data analysis shows a highly isotropic sky map and a nonuniform brightness distribution. Anisotropies expected from a Galactic neutron star population, the most frequently considered source model, did not emerge from the data. Taken at face value, the data seem to suggest a heliocentric solution of the GRB puzzle. The observed isotropy can be achieved if sources are either very near or extragalactic. Pop I neutron stars in the disk do not simultaneously fit sky and brightness distributions. A possibility are sources in an extended Galactic halo with scale length large enough to avoid strong anisotropies due to the solar offset from the Galactic center. If GRBs are located in an extended halo we ask whether the neutron star paradigm can survive. We show that the recently discovered high velocity radio pulsars may provide a natural source population for GRBs. If these pulsars formed in the halo, as suggested by the radio data, the possibility arises that GRBs and high velocity pulsars are two related phenomena that provide observational evidence of the dark Galactic corona. We also discuss cosmological redshift constraints that follow from the observed brightness distribution.

MAGNETIC STRUCTURES IN GAMMA-RAY BURST JETS PROBED BY GAMMA-RAY POLARIZATION

Energy Technology Data Exchange (ETDEWEB)

Yonetoku, Daisuke; Murakami, Toshio; Morihara, Yoshiyuki; Takahashi, Takuya; Wakashima, Yudai; Yonemochi, Hajime; Sakashita, Tomonori; Fujimoto, Hirofumi; Kodama, Yoshiki [College of Science and Engineering, School of Mathematics and Physics, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192 (Japan); Gunji, Shuichi; Toukairin, Noriyuki [Department of Physics, Faculty of Science, Yamagata University, 1-4-12, Koshirakawa, Yamagata, Yamagata 990-8560 (Japan); Mihara, Tatehiro [Cosmic Radiation Laboratory, RIKEN, 2-1, Hirosawa, Wako City, Saitama 351-0198 (Japan); Toma, Kenji, E-mail: yonetoku@astro.s.kanazawa-u.ac.jp [Department of Earth and Space Science, Osaka University, Toyonaka 560-0043 (Japan)

2012-10-10

We report polarization measurements in two prompt emissions of gamma-ray bursts, GRB 110301A and GRB 110721A, observed with the gamma-ray burst polarimeter (GAP) on borad the IKAROS solar sail mission. We detected linear polarization signals from each burst with polarization degree of {Pi} = 70 {+-} 22% with statistical significance of 3.7{sigma} for GRB 110301A, and {Pi} = 84{sup +16}{sub -28}% with 3.3{sigma} confidence level for GRB 110721A. We did not detect any significant change of polarization angle. These two events had shorter durations and dimmer brightness compared with GRB 100826A, which showed a significant change of polarization angle, as reported in Yonetoku et al. Synchrotron emission model can be consistent with the data of the three GRBs, while the photospheric quasi-thermal emission model is not favored. We suggest that magnetic field structures in the emission region are globally ordered fields advected from the central engine.

Linear Polarization, Circular Polarization, and Depolarization of Gamma-ray Bursts: A Simple Case of Jitter Radiation

Energy Technology Data Exchange (ETDEWEB)

Mao, Jirong; Wang, Jiancheng, E-mail: jirongmao@mail.ynao.ac.cn [Yunnan Observatories, Chinese Academy of Sciences, 650011 Kunming, Yunnan Province (China)

2017-04-01

Linear and circular polarizations of gamma-ray bursts (GRBs) have been detected recently. We adopt a simplified model to investigate GRB polarization characteristics in this paper. A compressed two-dimensional turbulent slab containing stochastic magnetic fields is considered, and jitter radiation can produce the linear polarization under this special magnetic field topology. Turbulent Faraday rotation measure (RM) of this slab makes strong wavelength-dependent depolarization. The jitter photons can also scatter with those magnetic clumps inside the turbulent slab, and a nonzero variance of the Stokes parameter V can be generated. Furthermore, the linearly and circularly polarized photons in the optical and radio bands may suffer heavy absorptions from the slab. Thus we consider the polarized jitter radiation transfer processes. Finally, we compare our model results with the optical detections of GRB 091018, GRB 121024A, and GRB 131030A. We suggest simultaneous observations of GRB multi-wavelength polarization in the future.

TESTING THE POSSIBLE INTRINSIC ORIGIN OF THE EXCESS VERY STRONG Mg II ABSORBERS ALONG GAMMA-RAY BURST LINES-OF-SIGHT

International Nuclear Information System (INIS)

Cucchiara, A.; Jones, T.; Charlton, J. C.; Fox, D. B.; Einsig, D.; Narayanan, A.

2009-01-01

The startling discovery by Prochter et al. that the frequency of very strong (W r (2796)>1 A) Mg II absorbers along gamma-ray burst (GRB) lines of sight ([dN/dz] GRB = 0.90) is more than three times the frequency along quasar lines of sight ([dN/dz] QSO = 0.24), over similar redshift ranges, has yet to be understood. In particular, explanations appealing to dust antibias in quasar samples, partial covering of the quasar sources, and gravitational-lensing amplification of the GRBs have all been carefully examined and found wanting. We therefore reconsider the possibility that the excess of very strong Mg II absorbers toward GRBs is intrinsic either to the GRBs themselves or to their immediate environment, and associated with bulk outflows with velocities as large as v max ∼ 0.3c. In order to examine this hypothesis, we accumulate a sample of 27 W r (2796)>1 A absorption systems found toward 81 quasars, and compare their properties to those of 8 W r (2796) > 1 A absorption systems found toward six GRBs; all systems have been observed at high spectral resolution (R = 45, 000) using the Ultraviolet and Visual Echelle Spectrograph on the Very Large Telescope. We make multiple comparisons of the absorber properties across the two populations, testing for differences in metallicity, ionization state, abundance patterns, dust abundance, kinematics, and phase structure. We find no significant differences between the two absorber populations using any of these metrics, implying that, if the excess of absorbers along GRB lines of sight are indeed intrinsic, they must be produced by a process which has strong similarities to the processes yielding strong Mg II systems associated with intervening galaxies. Although this may seem a priori unlikely, given the high outflow velocities required for any intrinsic model, we note that the same conclusion was reached, recently, with respect to the narrow absorption line systems seen in some quasars.

AFTERGLOW OBSERVATIONS OF FERMI LARGE AREA TELESCOPE GAMMA-RAY BURSTS AND THE EMERGING CLASS OF HYPER-ENERGETIC EVENTS

International Nuclear Information System (INIS)

Cenko, S. B.; Butler, N. R.; Cobb, B. E.; Cucchiara, A.; Bloom, J. S.; Perley, D. A.; Filippenko, A. V.; Frail, D. A.; Harrison, F. A.; Haislip, J. B.; Reichart, D. E.; Ivarsen, K. M.; LaCluyze, A. P.; Berger, E.; Chandra, P.; Fox, D. B.; Prochaska, J. X.; Glazebrook, K.; Kasliwal, M. M.; Kulkarni, S. R.

2011-01-01

We present broadband (radio, optical, and X-ray) light curves and spectra of the afterglows of four long-duration gamma-ray bursts (GRBs; GRBs 090323, 090328, 090902B, and 090926A) detected by the Gamma-Ray Burst Monitor and Large Area Telescope (LAT) instruments on the Fermi satellite. With its wide spectral bandpass, extending to GeV energies, Fermi is sensitive to GRBs with very large isotropic energy releases (10 54 erg). Although rare, these events are particularly important for testing GRB central-engine models. When combined with spectroscopic redshifts, our afterglow data for these four events are able to constrain jet collimation angles, the density structure of the circumburst medium, and both the true radiated energy release and the kinetic energy of the outflows. In agreement with our earlier work, we find that the relativistic energy budget of at least one of these events (GRB 090926A) exceeds the canonical value of 10 51 erg by an order of magnitude. Such energies pose a severe challenge for models in which the GRB is powered by a magnetar or a neutrino-driven collapsar, but remain compatible with theoretical expectations for magnetohydrodynamical collapsar models (e.g., the Blandford-Znajek mechanism). Our jet opening angles (θ) are similar to those found for pre-Fermi GRBs, but the large initial Lorentz factors (Γ 0 ) inferred from the detection of GeV photons imply θΓ 0 ∼ 70-90, values which are above those predicted in magnetohydrodynamic models of jet acceleration. Finally, we find that these Fermi-LAT events preferentially occur in a low-density circumburst environment, and we speculate that this might result from the lower mass-loss rates of their lower-metallicity progenitor stars. Future studies of Fermi-LAT afterglows at radio wavelengths with the order-of-magnitude improvement in sensitivity offered by the Extended Very Large Array should definitively establish the relativistic energy budgets of these events.

Observational constraints on the inter-binary stellar flare hypothesis for the gamma-ray bursts

Science.gov (United States)

Rao, A. R.; Vahia, M. N.

1994-01-01

The Gamma Ray Observatory/Burst and Transient Source Experiment (GRO/BATSE) results on the Gamma Ray Bursts (GRBs) have given an internally consistent set of observations of about 260 GRBs which have been released for analysis by the BATSE team. Using this database we investigate our earlier suggestion (Vahia and Rao, 1988) that GRBs are inter-binary stellar flares from a group of objects classified as Magnetically Active Stellar Systems (MASS) which includes flare stars, RS CVn binaries and cataclysmic variables. We show that there exists an observationally consistent parameter space for the number density, scale height and flare luminosity of MASS which explains the complete log(N) - log(P) distribution of GRBs as also the observed isotropic distribution. We further use this model to predict anisotropy in the GRB distribution at intermediate luminosities. We make definite predictions under the stellar flare hypothesis that can be tested in the near future.

Forming a constant density medium close to long gamma-ray burst

NARCIS (Netherlands)

Marle, A.J.; Langer, N.; Achterberg, A; Garia-Segura, G.

2006-01-01

Aims. The progenitor stars of long Gamma-Ray Bursts (GRBs) are thought to be Wolf-Rayet stars, which generate a massive and energetic wind. Nevertheless, about 25 percent of all GRB afterglows light curves indicate a constant density medium close to the exploding star. We explore various ways to

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 t...

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.

A metal-rich molecular cloud surrounds GRB 050904 at redshift 6.3

NARCIS (Netherlands)

Campana, S.; Lazzati, D.; Ripamonti, Emanuele; Perna, R.; Covino, S.; Tagliaferri, G.; Moretti, A.; Romano, P.; Cusumano, G.; Chincarini, G.

2007-01-01

GRB 050904 is the gamma-ray burst with the highest measured redshift. We performed time-resolved X-ray spectroscopy of the late GRB and early afterglow emission. We find robust evidence for a decrease with time of the soft X-ray-absorbing column. We model the evolution of the column density due to

XRF 100316D/SN 2010bh AND THE NATURE OF GAMMA-RAY BURST SUPERNOVAE

International Nuclear Information System (INIS)

Cano, Z.; Bersier, D.; Guidorzi, C.; Kobayashi, S.; Melandri, A.; Mundell, C. G.; Levan, A. J.; Tanvir, N. R.; Wiersema, K.; D'Avanzo, P.; Margutti, R.; Fruchter, A. S.; Garnavich, P.; Gomboc, A.; Kopac, D.; Gorosabel, J.; Kasen, D.; Mazzali, P. A.; Nugent, P. E.; Pian, E.

2011-01-01

We present ground-based and Hubble Space Telescope optical and infrared observations of Swift XRF 100316D/SN 2010bh. It is seen that the optical light curves of SN 2010bh evolve at a faster rate than the archetype gamma-ray burst supernova (GRB-SN) 1998bw, but at a similar rate to SN 2006aj, an SN that was spectroscopically linked with XRF 060218, and at a similar rate to the non-GRB associated Type Ic SN 1994I. We estimate the rest-frame extinction of this event from our optical data to be E(B - V) = 0.18 ± 0.08 mag. We find the V-band absolute magnitude of SN 2010bh to be M V = -18.62 ± 0.08, which is the faintest peak V-band magnitude observed to date for spectroscopically confirmed GRB-SNe. When we investigate the origin of the flux at t - t 0 = 0.598 days, it is shown that the light is not synchrotron in origin, but is likely coming from the SN shock breakout. We then use our optical and infrared data to create a quasi-bolometric light curve of SN 2010bh, which we model with a simple analytical formula. The results of our modeling imply that SN 2010bh synthesized a nickel mass of M Ni ∼ 0.1 M sun , ejected M ej ∼ 2.2 M sun , and has an explosion energy of E k ∼ 1.4 x 10 52 erg. Thus, while SN 2010bh is an energetic explosion, the amount of nickel created during the explosion is much less than that of SN 1998bw and only marginally more than SN 1994I. Finally, for a sample of 22 GRB-SNe we check for a correlation between the stretch factors and luminosity factors in the R band and conclude that no statistically significant correlation exists.

iPTF14yb: The First Discovery of a Gamma-Ray Burst Afterglow Independent of a High-Energy Trigger

Science.gov (United States)

Cenko, S. Bradley; Urban, Alex L.; Perley, Daniel A.; Horesh, Assaf; Corsi, Alessandra; Fox, Derek B.; Cao, Yi; Kasliwal, Mansi M.; Lien, Amy; Arcavi, Iair;

Effects of Fallback Accretion on Protomagnetar Outflows in Gamma-Ray Bursts and Superluminous Supernovae

Science.gov (United States)

Metzger, Brian D.; Beniamini, Paz; Giannios, Dimitrios

2018-04-01

Rapidly spinning, strongly magnetized protoneutron stars (“millisecond protomagnetars”) are candidate central engines of long-duration gamma-ray bursts (GRBs), superluminous supernovae (SLSNe), and binary neutron star mergers. Magnetar birth may be accompanied by the fallback of stellar debris, lasting for seconds or longer following the explosion. Accretion alters the magnetar evolution by (1) providing an additional source of rotational energy (or a potential sink, if the propeller mechanism operates), (2) enhancing the spin-down luminosity above the dipole rate by compressing the magnetosphere and expanding the polar cap region of open magnetic field lines, and (3) supplying an additional accretion-powered neutrino luminosity that sustains the wind baryon loading, even after the magnetar’s internal neutrino luminosity has subsided. The more complex evolution of the jet power and magnetization of an accreting magnetar more readily accounts for the high 56Ni yields of GRB SNe and the irregular time evolution of some GRB light curves (e.g., bursts with precursors followed by a long quiescent interval before the main emission episode). Additional baryon loading from accretion-powered neutrino irradiation of the polar cap lengthens the time frame over which the jet magnetization is in the requisite range σ ≲ 103 for efficient gamma-ray emission, thereby accommodating GRBs with ultralong durations. Though accretion does not significantly raise the maximum energy budget from the limit of ≲ few × 1052 erg for an isolated magnetar, it greatly expands the range of magnetic field strengths and birth spin periods capable of powering GRB jets, reducing the differences between the magnetar properties normally invoked to explain GRBs versus SLSNe.

Can past gamma-ray bursts explain both INTEGRAL and ATIC/PAMELA/Fermi anomalies simultaneously?

International Nuclear Information System (INIS)

Calvez, Antoine; Kusenko, Alexander

2010-01-01

Gamma-ray bursts (GRBs) have been invoked to explain both the 511 keV emission from the Galactic bulge and the high-energy positron excess inferred from the ATIC, PAMELA, and Fermi data. While independent explanations can be responsible for these phenomena, we explore the possibility of their common GRB-related origin by modeling the GRB distribution and estimating the rates. For an expected Milky Way long GRB rate, neither of the two signals is generic; the local excess requires a 2% coincidence while the signal from the Galactic center requires a 20% coincidence with respect to the timing of the latest GRB. The simultaneous explanation requires a 0.4% coincidence. Considering the large number of statistical 'trials' created by multiple searches for new physics, the coincidences of a few percent cannot be dismissed as unlikely. Alternatively, both phenomena can be explained by GRB if the Galactic rate is higher than expected. We also show that a similar result is difficult to obtain assuming a simplified short GRB distribution.

The Supercritical Pile GRB Model: The Prompt to Afterglow Evolution

Science.gov (United States)

Mastichiadis, A.; Kazanas, D.

2009-01-01

The "Supercritical Pile" is a very economical GRB model that provides for the efficient conversion of the energy stored in the protons of a Relativistic Blast Wave (RBW) into radiation and at the same time produces - in the prompt GRB phase, even in the absence of any particle acceleration - a spectral peak at energy approx. 1 MeV. We extend this model to include the evolution of the RBW Lorentz factor Gamma and thus follow its spectral and temporal features into the early GRB afterglow stage. One of the novel features of the present treatment is the inclusion of the feedback of the GRB produced radiation on the evolution of Gamma with radius. This feedback and the presence of kinematic and dynamic thresholds in the model can be the sources of rich time evolution which we have began to explore. In particular. one can this may obtain afterglow light curves with steep decays followed by the more conventional flatter afterglow slopes, while at the same time preserving the desirable features of the model, i.e. the well defined relativistic electron source and radiative processes that produce the proper peak in the (nu)F(sub nu), spectra. In this note we present the results of a specific set of parameters of this model with emphasis on the multiwavelength prompt emission and transition to the early afterglow.

Five Years of Multi-frequency Monitoring of GRB030329 Afterglow Using the GMRT and WSRT

International Nuclear Information System (INIS)

Kamble, Atish; Wijers, Ralph; Rol, Evert; Horst, A. J. van der; Kouveliotou, Chryssa; Bhattacharya, D.; Chandra, C. H. Ishwara; Resmi, L.; Strom, R.

2009-01-01

GRB 030329 displayed one of the brightest optical afterglows ever. We have followed the radio afterglow of GRB 030329 for over 5 years using the GMRT and WSRT at low radio frequencies. This is the longest as well as the lowest frequency follow up of any GRB afterglow ever.Radio observations of a GRB afterglow provide a unique probe of the physics of the blast wave at late times, when the expansion of the fireball slows down to non-relativistic speeds. Our GMRT-WSRT observations suggest that the afterglow of GRB030329 entered the non-relativistic phase around 60 days after the burst. The estimate of the fireball energy content, ∼10 51 erg, in this near-isotropic phase is much less susceptible to the collimation-related uncertainties arising in the relativistic phase. We have also been closely monitoring the evolution of the afterglow to look for possible signatures of emission from a counter jet, but no conclusive evidence has so far been found.

Solution structure of the Grb2 SH2 domain complexed with a high-affinity inhibitor

International Nuclear Information System (INIS)

Ogura, Kenji; Shiga, Takanori; Yokochi, Masashi; Yuzawa, Satoru; Burke, Terrence R.; Inagaki, Fuyuhiko

2008-01-01

The solution structure of the growth factor receptor-bound protein 2 (Grb2) SH2 domain complexed with a high-affinity inhibitor containing a non-phosphorus phosphate mimetic within a macrocyclic platform was determined by nuclear magnetic resonance (NMR) spectroscopy. Unambiguous assignments of the bound inhibitor and intermolecular NOEs between the Grb2 SH2 domain and the inhibitor was accomplished using perdeuterated Grb2 SH2 protein. The well-defined solution structure of the complex was obtained and compared to those by X-ray crystallography. Since the crystal structure of the Grb2 SH2 domain formed a domain-swapped dimer and several inhibitors were bound to a hinge region, there were appreciable differences between the solution and crystal structures. Based on the binding interactions between the inhibitor and the Grb2 SH2 domain in solution, we proposed a design of second-generation inhibitors that could be expected to have higher affinity

Gas Kinematics in GRB Host Galaxies

DEFF Research Database (Denmark)

Arabsalmani, Maryam

towards a relation between gas kinematics and mass. This also provides information on how the metallicities measured from absorption and emission methods differ from each other. Finally, in a direct study I show that gas velocity widths in both phases can be used as a proxy of stellar mass...... that their interstellar media imprint on the GRBs’ spectra. Hence they are invaluable tools to probe the star formation history of the Universe back to the earliest cosmic epochs. To this end, it is essential to achieve a comprehensive picture of the interplay between star formation and its fuel, neutral gas, in GRB...... simultaneously with a high velocity resolution. For the large GRB sample, I find the spatially averaged velocity to correlate with metallicity in both gas phases. This is an indicator of a mass-metallicity relation. Moreover, the velocity widths in the two gas phases correlate with each other which too points...

The host galaxy of GRB 990712

DEFF Research Database (Denmark)

Christensen, L.; Hjorth, J.; Gorosabel, J.

2004-01-01

We present a comprehensive study of the z = 0.43 host galaxy of GRB 990712, involving ground-based photometry, spectroscopy, and HST imaging. The broad-band UBVRIJHKs photometry is used to determine the global spectral energy distribution (SED) of the host galaxy. Comparison with that of known...... galaxy types shows that the host is similar to a moderately kreddened starburst galaxy with a young stellar population. The estimated internal extinction in the host is A(V) = 0.15 +/- 0.1 and the star-formation rate (SFR) from the UV continuum is 1.3 +/- 0.3 M-circle dot yr(-1) (not corrected...... for the effects of extinction). Other galaxy template spectra than starbursts failed to reproduce the observed SED. We also present VLT spectra leading to the detection of Halpha from the GRB host galaxy. A SFR of 2.8 +/- 0.7 M-circle dot yr(-1) is inferred from the Halpha line flux, and the presence of a young...

Growth factor receptor-binding protein 10 (Grb10) as a partner of phosphatidylinositol 3-kinase in metabolic insulin action.

Science.gov (United States)

Deng, Youping; Bhattacharya, Sujoy; Swamy, O Rama; Tandon, Ruchi; Wang, Yong; Janda, Robert; Riedel, Heimo

2003-10-10

The regulation of the metabolic insulin response by mouse growth factor receptor-binding protein 10 (Grb10) has been addressed in this report. We find mouse Grb10 to be a critical component of the insulin receptor (IR) signaling complex that provides a functional link between IR and p85 phosphatidylinositol (PI) 3-kinase and regulates PI 3-kinase activity. This regulatory mechanism parallels the established link between IR and p85 via insulin receptor substrate (IRS) proteins. A direct association was demonstrated between Grb10 and p85 but was not observed between Grb10 and IRS proteins. In addition, no effect of mouse Grb10 was observed on the association between IRS-1 and p85, on IRS-1-associated PI 3-kinase activity, or on insulin-mediated activation of IR or IRS proteins. A critical role of mouse Grb10 was observed in the regulation of PI 3-kinase activity and the resulting metabolic insulin response. Dominant-negative Grb10 domains, in particular the SH2 domain, eliminated the metabolic response to insulin in differentiated 3T3-L1 adipocytes. This was consistently observed for glycogen synthesis, glucose and amino acid transport, and lipogenesis. In parallel, the same metabolic responses were substantially elevated by increased levels of Grb10. A similar role of Grb10 was confirmed in mouse L6 cells. In addition to the SH2 domain, the Pro-rich amino-terminal region of Grb10 was implicated in the regulation of PI 3-kinase catalytic activity. These regulatory roles of Grb10 were extended to specific insulin mediators downstream of PI 3-kinase including PKB/Akt, glycogen synthase kinase, and glycogen synthase. In contrast, a regulatory role of Grb10 in parallel insulin response pathways including p70 S6 kinase, ubiquitin ligase Cbl, or mitogen-activated protein kinase p38 was not observed. The dissection of the interaction of mouse Grb10 with p85 and the resulting regulation of PI 3-kinase activity should help elucidate the complexity of the IR signaling

A novel redox-based switch: LMW-PTP oxidation enhances Grb2 binding and leads to ERK activation

International Nuclear Information System (INIS)

Giannoni, Elisa; Raugei, Giovanni; Chiarugi, Paola; Ramponi, Giampietro

2006-01-01

Low molecular weight-PTP has been reported as a redox-sensitive protein during both platelet-derived growth factor and integrin signalling. In response to oxidation the phosphatase undergoes a reversible inactivation, which in turn leads to the increase in tyrosine phosphorylation of its substrates and the properly executed anchorage-dependent proliferation program. Here, we report that an exogenous oxidative stress enhances LMW-PTP tyrosine phosphorylation, through oxidation/inactivation of the enzyme, thus preventing its auto-dephosphorylation activity. In particular, we observed a selective hyper-phosphorylation of Tyr132, that acts as a docking site for the adaptor protein Grb2. The redox-dependent enhancement of Grb2 recruitment to LMW-PTP ultimately leads to an improvement of ERK activation, likely triggering a prosurvival signal against the oxidant environment

Deletion of the calmodulin-binding domain of Grb7 impairs cell attachment to the extracellular matrix and migration

Energy Technology Data Exchange (ETDEWEB)

García-Palmero, Irene; Villalobo, Antonio, E-mail: antonio.villalobo@iib.uam.es

2013-06-28

Highlights: •Grb7 is a calmodulin (CaM)-binding protein. •Deleting the CaM-binding site impairs cell attachment and migration. •CaM antagonists inhibit Grb7-mediated cell migration. •We conclude that CaM controls Grb7-mediated cell migration. -- Abstract: The adaptor Grb7 is a calmodulin (CaM)-binding protein that participates in signaling pathways involved in cell migration, proliferation and the control of angiogenesis, and plays a significant role in tumor growth, its metastatic spread and tumor-associated neo-vasculature formation. In this report we show that deletion of the CaM-binding site of Grb7, located in the proximal region of its pleckstrin homology (PH) domain, impairs cell migration, cell attachment to the extracellular matrix, and the reorganization of the actin cytoskeleton occurring during this process. Moreover, we show that the cell-permeable CaM antagonists N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) and N-(4-aminobutyl)-5-chloro-2-naphthalenesulfonamide (W-13) both retard the migration of cells expressing wild type Grb7, but not the migration of cells expressing the mutant protein lacking the CaM-binding site (Grb7Δ), underscoring the proactive role of CaM binding to Grb7 during this process.

GRBOX: A New Online Catalog of GRBs

International Nuclear Information System (INIS)

Perley, Daniel; Kemper, Yvonne

2008-01-01

With Swift detecting close to 100 new gamma-ray bursts each year, cataloging past bursts is more important than ever. To this end, we present a new online database (GRBOX: Gamma Ray Burst Online IndeX) indexing properties of every well-localized GRB since 1997. Unlike existing resources, the information in the catalog is presented to the user in the form of a sortable, filterable table and derives information for each burst from published catalogs as well as the GCN circulars and refereed publications. Short text summaries and links to other resources are also provided for every event

A central role for GRB10 in regulation of islet function in man.

Directory of Open Access Journals (Sweden)

Inga Prokopenko

2014-04-01

Full Text Available Variants in the growth factor receptor-bound protein 10 (GRB10 gene were in a GWAS meta-analysis associated with reduced glucose-stimulated insulin secretion and increased risk of type 2 diabetes (T2D if inherited from the father, but inexplicably reduced fasting glucose when inherited from the mother. GRB10 is a negative regulator of insulin signaling and imprinted in a parent-of-origin fashion in different tissues. GRB10 knock-down in human pancreatic islets showed reduced insulin and glucagon secretion, which together with changes in insulin sensitivity may explain the paradoxical reduction of glucose despite a decrease in insulin secretion. Together, these findings suggest that tissue-specific methylation and possibly imprinting of GRB10 can influence glucose metabolism and contribute to T2D pathogenesis. The data also emphasize the need in genetic studies to consider whether risk alleles are inherited from the mother or the father.

Slewing Mirror Telescope and the Data-Acquisition System for the UFFO-Pathfinder

DEFF Research Database (Denmark)

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

2013-01-01

The Ultra-Fast Flash Observatory (UFFO) aims to detect the earliest moment of Gamma-Ray Bursts (GRBs) which is not well known, resulting into the enhancement of GRB mechanism understanding. The pathfinder mission was proposed to be a scaled-down version of UFFO, and only contains the UFFO Burst A...

Gamma-ray bursts from stellar remnants - Probing the universe at high redshift

NARCIS (Netherlands)

Wijers, R.A.M.J.; Bloom, J.S.; Bagla, J.S.; Natarajan, P.

1998-01-01

A gamma-ray burst (GRB) releases an amount of energy similar to that of a supernova explosion, which combined with its rapid variability suggests an origin related to neutron stars or black holes. Since these compact stellar remnants form from the most massive stars not long after their birth, GRBs

NUMERICAL AND ANALYTICAL SOLUTIONS OF NEUTRINO-DOMINATED ACCRETION FLOWS WITH A NON-ZERO TORQUE BOUNDARY CONDITION AND ITS APPLICATIONS IN GAMMA-RAY BURSTS

Energy Technology Data Exchange (ETDEWEB)

Xie, Wei; Lei, Wei-Hua; Wang, Ding-Xiong, E-mail: leiwh@hust.edu.cn [School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China)

2016-12-20

A stellar-mass black hole (BH) surrounded by a neutrino-dominated accretion flow (NDAF) has been discussed in a number of works as the central engine of gamma-ray bursts (GRBs). It is widely believed that NDAF cannot liberate enough energy for bright GRBs. However, these works have been based on the assumption of a “no torque” boundary condition, which is invalid when the disk is magnetized. In this paper, we present both numerical and analytical solutions for NDAFs with non-zero boundary stresses and reexamine their properties. We find that an NDAF with such a boundary torque can be powerful enough to account for those bright short GRBs, energetic long GRBs, and ultra-long GRBs. The disk becomes viscously unstable, which makes it possible to interpret the variability of GRB prompt emission and the steep decay phase in the early X-ray afterglow. Finally, we study the gravitational waves radiated from a processing BH-NDAF. We find that the effects of the boundary torque on the strength of the gravitational waves can be ignored.

GRB 161219B / SN 2016jca: A low-redshift gamma-ray burst supernova powered by radioactive heating

DEFF Research Database (Denmark)

Cano, Z.; Izzo, L.; De Ugarte Postigo, A.

2017-01-01

Since the first discovery of a broad-lined type Ic supernova (SN) with a long-duration gamma-ray burst (GRB) in 1998, fewer than fifty gamma-ray burst supernovae (GRB-SNe) have been discovered. The intermediate-luminosity Swift GRB 161219B and its associated supernova SN 2016jca, which occurred a...

THE FIRST FERMI-LAT GAMMA-RAY BURST CATALOG

Energy Technology Data Exchange (ETDEWEB)

Ackermann, M. [Deutsches Elektronen Synchrotron DESY, D-15738 Zeuthen (Germany); Ajello, M. [Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720-7450 (United States); Asano, K. [Interactive Research Center of Science, Tokyo Institute of Technology, Meguro City, Tokyo 152-8551 (Japan); Axelsson, M. [Department of Astronomy, Stockholm University, SE-106 91 Stockholm (Sweden); Baldini, L. [Università di Pisa and Istituto Nazionale di Fisica Nucleare, Sezione di Pisa I-56127 Pisa (Italy); Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Université Paris Diderot, Service d' Astrophysique, CEA Saclay, 91191 Gif sur Yvette (France); Barbiellini, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Bastieri, D. [Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy); Bechtol, K.; Bloom, E. D. [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); Bellazzini, R.; Bregeon, J. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Bhat, P. N. [Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Bissaldi, E. [Institut für Astro- und Teilchenphysik and Institut für Theoretische Physik, Leopold-Franzens-Universität Innsbruck, A-6020 Innsbruck (Austria); Bonamente, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy); Bonnell, J.; Brandt, T. J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Bouvier, A., E-mail: nicola.omodei@stanford.edu, E-mail: giacomov@slac.stanford.edu [Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); and others

2013-11-01

In three years of observations since the beginning of nominal science operations in 2008 August, the Large Area Telescope (LAT) on board the Fermi Gamma-Ray Space Telescope has observed high-energy (∼> 20 MeV) γ-ray emission from 35 gamma-ray bursts (GRBs). Among these, 28 GRBs have been detected above 100 MeV and 7 GRBs above ∼20 MeV. The first Fermi-LAT catalog of GRBs is a compilation of these detections and provides a systematic study of high-energy emission from GRBs for the first time. To generate the catalog, we examined 733 GRBs detected by the Gamma-Ray Burst Monitor (GBM) on Fermi and processed each of them using the same analysis sequence. Details of the methodology followed by the LAT collaboration for the GRB analysis are provided. We summarize the temporal and spectral properties of the LAT-detected GRBs. We also discuss characteristics of LAT-detected emission such as its delayed onset and longer duration compared with emission detected by the GBM, its power-law temporal decay at late times, and the fact that it is dominated by a power-law spectral component that appears in addition to the usual Band model.

The First FERMI-LAT Gamma-Ray Burst Catalog

Science.gov (United States)

Ackermann, M.; Ajello, M.; Asano, K.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.;

THE FIRST FERMI-LAT GAMMA-RAY BURST CATALOG

International Nuclear Information System (INIS)

Ackermann, M.; Ajello, M.; Asano, K.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bloom, E. D.; Bellazzini, R.; Bregeon, J.; Bhat, P. N.; Bissaldi, E.; Bonamente, E.; Bonnell, J.; Brandt, T. J.; Bouvier, A.

2013-01-01

In three years of observations since the beginning of nominal science operations in 2008 August, the Large Area Telescope (LAT) on board the Fermi Gamma-Ray Space Telescope has observed high-energy (∼> 20 MeV) γ-ray emission from 35 gamma-ray bursts (GRBs). Among these, 28 GRBs have been detected above 100 MeV and 7 GRBs above ∼20 MeV. The first Fermi-LAT catalog of GRBs is a compilation of these detections and provides a systematic study of high-energy emission from GRBs for the first time. To generate the catalog, we examined 733 GRBs detected by the Gamma-Ray Burst Monitor (GBM) on Fermi and processed each of them using the same analysis sequence. Details of the methodology followed by the LAT collaboration for the GRB analysis are provided. We summarize the temporal and spectral properties of the LAT-detected GRBs. We also discuss characteristics of LAT-detected emission such as its delayed onset and longer duration compared with emission detected by the GBM, its power-law temporal decay at late times, and the fact that it is dominated by a power-law spectral component that appears in addition to the usual Band model

A deceleration search for magnetar pulsations in the X-ray plateaus of short GRBs

Science.gov (United States)

Rowlinson, A.; Patruno, A.; O'Brien, P. T.

2017-11-01

A newly formed magnetar has been proposed as the central engine of short GRBs to explain ongoing energy injection giving observed plateau phases in the X-ray light curves. These rapidly spinning magnetars may be capable of emitting pulsed emission comparable to known pulsars and magnetars. In this paper we show that, if present, a periodic signal would be detectable during the plateau phases observed using the Swift/X-Ray Telescope recording data in Window Timing mode. We conduct a targeted deceleration search for a periodic signal from a newly formed magnetar in 2 Swift short GRBs and rule out any periodic signals in the frequency band 10-285 Hz to ≈15-30 per cent rms. These results demonstrate that we would be able to detect pulsations from the magnetar central engine of short GRBs if they contribute to 15-30 per cent of the total emission. We consider these constraints in the context of the potential emission mechanisms. The non-detection is consistent with the emission being reprocessed in the surrounding environment or with the rotation axis being highly aligned with the observing angle. As the emission may be reprocessed, the expected periodic emission may only constitute a few per cent of the total emission and be undetectable in our observations. Applying this strategy to future observations of the plateau phases with more sensitive X-ray telescopes may lead to the detection of the periodic signal.

Grb7 SH2 domain structure and interactions with a cyclic peptide inhibitor of cancer cell migration and proliferation

Directory of Open Access Journals (Sweden)

Pero Stephanie C

2007-09-01

Full Text Available Abstract Background Human growth factor receptor bound protein 7 (Grb7 is an adapter protein that mediates the coupling of tyrosine kinases with their downstream signaling pathways. Grb7 is frequently overexpressed in invasive and metastatic human cancers and is implicated in cancer progression via its interaction with the ErbB2 receptor and focal adhesion kinase (FAK that play critical roles in cell proliferation and migration. It is thus a prime target for the development of novel anti-cancer therapies. Recently, an inhibitory peptide (G7-18NATE has been developed which binds specifically to the Grb7 SH2 domain and is able to attenuate cancer cell proliferation and migration in various cancer cell lines. Results As a first step towards understanding how Grb7 may be inhibited by G7-18NATE, we solved the crystal structure of the Grb7 SH2 domain to 2.1 Å resolution. We describe the details of the peptide binding site underlying target specificity, as well as the dimer interface of Grb 7 SH2. Dimer formation of Grb7 was determined to be in the μM range using analytical ultracentrifugation for both full-length Grb7 and the SH2 domain alone, suggesting the SH2 domain forms the basis of a physiological dimer. ITC measurements of the interaction of the G7-18NATE peptide with the Grb7 SH2 domain revealed that it binds with a binding affinity of Kd = ~35.7 μM and NMR spectroscopy titration experiments revealed that peptide binding causes perturbations to both the ligand binding surface of the Grb7 SH2 domain as well as to the dimer interface, suggesting that dimerisation of Grb7 is impacted on by peptide binding. Conclusion Together the data allow us to propose a model of the Grb7 SH2 domain/G7-18NATE interaction and to rationalize the basis for the observed binding specificity and affinity. We propose that the current study will assist with the development of second generation Grb7 SH2 domain inhibitors, potentially leading to novel inhibitors of

A gamma-ray burst at a redshift of z approximately 8.2.

Science.gov (United States)

Tanvir, N R; Fox, D B; Levan, A J; Berger, E; Wiersema, K; Fynbo, J P U; Cucchiara, A; Krühler, T; Gehrels, N; Bloom, J S; Greiner, J; Evans, P A; Rol, E; Olivares, F; Hjorth, J; Jakobsson, P; Farihi, J; Willingale, R; Starling, R L C; Cenko, S B; Perley, D; Maund, J R; Duke, J; Wijers, R A M J; Adamson, A J; Allan, A; Bremer, M N; Burrows, D N; Castro-Tirado, A J; Cavanagh, B; de Ugarte Postigo, A; Dopita, M A; Fatkhullin, T A; Fruchter, A S; Foley, R J; Gorosabel, J; Kennea, J; Kerr, T; Klose, S; Krimm, H A; Komarova, V N; Kulkarni, S R; Moskvitin, A S; Mundell, C G; Naylor, T; Page, K; Penprase, B E; Perri, M; Podsiadlowski, P; Roth, K; Rutledge, R E; Sakamoto, T; Schady, P; Schmidt, B P; Soderberg, A M; Sollerman, J; Stephens, A W; Stratta, G; Ukwatta, T N; Watson, D; Westra, E; Wold, T; Wolf, C

2009-10-29

Long-duration gamma-ray bursts (GRBs) are thought to result from the explosions of certain massive stars, and some are bright enough that they should be observable out to redshifts of z > 20 using current technology. Hitherto, the highest redshift measured for any object was z = 6.96, for a Lyman-alpha emitting galaxy. Here we report that GRB 090423 lies at a redshift of z approximately 8.2, implying that massive stars were being produced and dying as GRBs approximately 630 Myr after the Big Bang. The burst also pinpoints the location of its host galaxy.

Performance and scientific results of the BeppoSAX Gamma-Ray Burst Monitor

International Nuclear Information System (INIS)

Feroci, M.; Costa, E.; Cinti, M. N.; Frontera, F.; Dal Fiume, D.; Nicastro, L.; Orlandini, M.; Palazzi, E.; Amati, L.; Zavattini, G.; Coletta, A.

1998-01-01

The Italian-Dutch satellite for X-ray Astronomy BeppoSAX is successfully operating on a 600 km equatorial orbit since May 1996. We present here the in-flight performance of the Gamma Ray Burst Monitor (GRBM) experiment during its first year of operation. The GRBM is performing very well, providing an amount of data on GRBs, some of which confirmed by other experiments onboard satellites. It also joined the 3rd Interplanetary Network as a new near-earth node. Important results have been obtained for GRBs (e.g. GRB970228) simultaneously detected in the Wide Field Cameras onboard the same satellite

Cosmic gamma-ray bursts

International Nuclear Information System (INIS)

Hurley, K.

1989-01-01

This paper reviews the essential aspects of the gamma-ray burst (GRB) phenomenon, with emphasis on the more recent results. GRBs are introduced by their time histories, which provide some evidence for a compact object origin. The energy spectra of bursts are presented and they are seen to demonstrate practically unambiguously that the origin of some GRBs involves neutron stars. Counterpart searches are reviewed briefly and the statistical properties of bursters treated. This paper presents a review of the three known repeating bursters (the Soft Gamma Repeaters). Extragalactic and galactic models are discussed and future prospects are assessed

Gamma-Ray Burst Prompt Correlations

Directory of Open Access Journals (Sweden)

M. G. Dainotti

2018-01-01

Full Text Available The mechanism responsible for the prompt emission of gamma-ray bursts (GRBs is still a debated issue. The prompt phase-related GRB correlations can allow discriminating among the most plausible theoretical models explaining this emission. We present an overview of the observational two-parameter correlations, their physical interpretations, and their use as redshift estimators and possibly as cosmological tools. The nowadays challenge is to make GRBs, the farthest stellar-scaled objects observed (up to redshift z=9.4, standard candles through well established and robust correlations. However, GRBs spanning several orders of magnitude in their energetics are far from being standard candles. We describe the advances in the prompt correlation research in the past decades, with particular focus paid to the discoveries in the last 20 years.

Multiwavelength analysis of the intriguing GRB 061126: The reverse shock scenario and magnetization

NARCIS (Netherlands)

Gomboc, A.; Kobayashi, S.; Guidorzi, C.; Melandri, A.; Mangano, V.; Sbarufatti, B.; Mundell, C.G.; Schady, P.; Smith, R.J.; Updike, A.C.; Kann, D.A.; Misra, K.; Rol, E.; Pozanenko, A.; Castro-Tirado, A.J.; Anupama, G.C.; Bersier, D.; Bode, M.F.; Carter, D.; Curran, P.; Fruchter, A.; Graham, J.; Hartmann, D.H.; Ibrahimov, M.; Levan, A.; Monfardini, A.; Mottram, C.J.; O'Brien, P.T.; Prema, P.; Sahu, D.K.; Steele, I.A.; Tanvir, N.R.; Wiersema, K.

2008-01-01

We present a detailed study of the prompt and afterglow emission from Swift GRB 061126 using BAT, XRT, UVOT data and multicolor optical imaging from 10 ground-based telescopes. GRB 061126 was a long burst (T90 = 191 s) with four overlapping peaks in its γ-ray light curve. The X-ray afterglow,

Millimetre observations of gamma-ray bursts at IRAM

DEFF Research Database (Denmark)

Castro-Tirado, A. J.; Bremer, M.; Winters, J. M.

2013-01-01

Since 1997, and following our detection of the first mm afterglow, we have followed-up 70 GRBs, mainly with the IRAMÅ Plateau de Bure Interferometer, what can be considered as the IRAM Legacy GRB Sample. 66 events were observed at 3 mm, with 19 of them being detected (with another 3 having margin...

UFFO/Lomonosov: The Payload for the Observation of Early Photons from Gamma Ray Bursts

DEFF Research Database (Denmark)

Park, I. H.; Panasyuk, M. I.; Reglero, V.

2018-01-01

. Fast response measurements of the optical emission of GRB will be made by a Slewing Mirror Telescope (SMT), a key instrument of the payload, which will open a new frontier in transient studies by probing the early optical rise of GRBs with a response time in seconds for the first time. The SMT employs...... a rapidly slewing mirror to redirect the optical axis of the telescope to a GRB position prior determined by the UFFO Burst Alert Telescope (UBAT), the other onboard instrument, for the observation and imaging of X-rays. UFFO/Lomonosov was launched successfully from Vostochny, Russia on April 28, 2016...

Short GRB afterglows observed with GROND

DEFF Research Database (Denmark)

Nicuesa Guelbenzu, A.; Klose, S.; Rossi, A.

2013-01-01

We report on follow-up observations of 20 short-duration gamma-ray bursts (T90 < 2s) performed in g′r′i′z′JHK s with the Gamma-Ray Burst Optical Near-Infrared Detector (GROND) between mid-2007 and the end of 2010. This is the most homogeneous and comprehensive data set on GRB afterglow observatio...

Grb2 mediates semaphorin-4D-dependent RhoA inactivation.

Science.gov (United States)

Sun, Tianliang; Krishnan, Rameshkumar; Swiercz, Jakub M

2012-08-01

Signaling through the semaphorin 4D (Sema4D) receptor plexin-B1 is modulated by its interaction with tyrosine kinases ErbB-2 and Met. In cells expressing the plexin-B1-ErbB-2 receptor complex, ligand stimulation results in the activation of small GTPase RhoA and stimulation of cellular migration. By contrast, in cells expressing plexin-B1 and Met, ligand stimulation results in an association with the RhoGTPase-activating protein p190 RhoGAP and subsequent RhoA inactivation--a process that involves the tyrosine phosphorylation of plexin-B1 by Met. Inactivation of RhoA is necessary for Sema4D-mediated inhibition of cellular migration. It is, however, unknown how plexin-B1 phosphorylation regulates RhoGAP interaction and activity. Here we show that the activation of plexin-B1 by Sema4D and its subsequent tyrosine phosphorylation by Met creates a docking site for the SH2 domain of growth factor receptor bound-2 (Grb2). Grb2 is thereby recruited into the plexin-B1 receptor complex and, through its SH3 domain, interacts with p190 RhoGAP and mediates RhoA deactivation. Phosphorylation of plexin-B1 by Met and the recruitment of Grb2 have no effect on the R-RasGAP activity of plexin-B1, but are required for Sema4D-induced, RhoA-dependent antimigratory effects of Sema4D on breast cancer cells. These data show Grb2 as a direct link between plexin and p190-RhoGAP-mediated downstream signaling.

Using gamma-ray bursts to probe the cosmic intergalactic medium

Energy Technology Data Exchange (ETDEWEB)

Sudilovsky, Vladimir

2014-05-28

Gamma-ray bursts (GRBs) rapidly liberate enormous amounts of energy through the cataclysmic destruction of an individual massive object. GRBs are the most energetic events in the Universe, boasting isotropic equivalent energy releases of E∝10{sup 51-54} erg in time scales of seconds - more energy than even active galaxies in the same time-frame. These transient events represent the ultimate high energy laboratories, and their afterglows are readily detectable from ground-based observatories out to cosmological distances out to z∝8. For this reason, GRBs are a natural tool to probe the early universe. To this end, programs to quickly measure the photometric and spectroscopic properties of GRB afterglows are providing a wealth of data that enable us to characterize the physical properties of both the burst itself and its host environment. In addition to providing extremely poignant information on the burst and its medium, GRB afterglow spectra show the presence of matter intervening along the line of sight. MgII, an important tracer of α-element processes and thus of star formation and galaxies, has been measured in ∝ 60% of GRB afterglow spectra. Surprisingly, MgII is only found in ∝30% of quasar spectra. This discrepancy in the number density dn/dz of intervening MgII absorbers implies that there are significant observational biases in either the spectroscopic samples of either GRB afterglows or quasars. In this work, we review the MgII issue and the biases proposed to explain it. We find that observations of other tracer systems (namely CIV) do not show the same overdensity, and thus conclude that solution to the MgII problem is related to the geometry of the sight-line relative to the absorbers. We conclude that an observational bias stemming from dust extinction arising from MgII cannot explain such a large discrepancy. Finally, we search for a signal of the MgII discrepancy in the transverse direction by computing the GRB-galaxy two point correlation

Using gamma-ray bursts to probe the cosmic intergalactic medium

International Nuclear Information System (INIS)

Sudilovsky, Vladimir

2014-01-01

Gamma-ray bursts (GRBs) rapidly liberate enormous amounts of energy through the cataclysmic destruction of an individual massive object. GRBs are the most energetic events in the Universe, boasting isotropic equivalent energy releases of E∝10 51-54 erg in time scales of seconds - more energy than even active galaxies in the same time-frame. These transient events represent the ultimate high energy laboratories, and their afterglows are readily detectable from ground-based observatories out to cosmological distances out to z∝8. For this reason, GRBs are a natural tool to probe the early universe. To this end, programs to quickly measure the photometric and spectroscopic properties of GRB afterglows are providing a wealth of data that enable us to characterize the physical properties of both the burst itself and its host environment. In addition to providing extremely poignant information on the burst and its medium, GRB afterglow spectra show the presence of matter intervening along the line of sight. MgII, an important tracer of α-element processes and thus of star formation and galaxies, has been measured in ∝ 60% of GRB afterglow spectra. Surprisingly, MgII is only found in ∝30% of quasar spectra. This discrepancy in the number density dn/dz of intervening MgII absorbers implies that there are significant observational biases in either the spectroscopic samples of either GRB afterglows or quasars. In this work, we review the MgII issue and the biases proposed to explain it. We find that observations of other tracer systems (namely CIV) do not show the same overdensity, and thus conclude that solution to the MgII problem is related to the geometry of the sight-line relative to the absorbers. We conclude that an observational bias stemming from dust extinction arising from MgII cannot explain such a large discrepancy. Finally, we search for a signal of the MgII discrepancy in the transverse direction by computing the GRB-galaxy two point correlation

Dust reddening and extinction curves toward gamma-ray bursts at z > 4

Science.gov (United States)

Bolmer, J.; Greiner, J.; Krühler, T.; Schady, P.; Ledoux, C.; Tanvir, N. R.; Levan, A. J.

2018-01-01

Context. Dust is known to be produced in the envelopes of asymptotic giant branch (AGB) stars, the expanded shells of supernova (SN) remnants, and in situ grain growth within the interstellar medium (ISM), although the corresponding efficiency of each of these dust formation mechanisms at different redshifts remains a topic of debate. During the first Gyr after the Big Bang, it is widely believed that there was not enough time to form AGB stars in high numbers, hence the dust at this epoch is expected to be purely from SNe or subsequent grain growth in the ISM. The time period corresponding to z 5-6 is thus expected to display the transition from SN-only dust to a mixture of both formation channels as is generally recognized at present. Aims: Here we aim to use afterglow observations of gamma-ray bursts (GRBs) at redshifts larger than z > 4 to derive host galaxy dust column densities along their line of sight and to test if a SN-type dust extinction curve is required for some of the bursts. Methods: We performed GRB afterglow observations with the seven-channel Gamma-Ray Optical and Near-infrared Detector (GROND) at the 2.2 m MPI telescope in La Silla, Chile (ESO), and we combined these observations with quasi-simultaneous data gathered with the XRT telescope on board the Swift satellite. Results: We increase the number of measured AV values for GRBs at z > 4 by a factor of 2-3 and find that, in contrast to samples at mostly lower redshift, all of the GRB afterglows have a visual extinction of AV different scenarios. For the first time we also report a photometric redshift of zphot = 7.88-0.94+0.75 for GRB 100905A, making it one of the most distant GRBs known to date.

Jet models of X-Ray Flashes

International Nuclear Information System (INIS)

Lamb, D.Q.; Donaghy, T.Q.; Graziani, C.

2005-01-01

One third of all HETE-2-localized bursts are X-Ray Flashes (XRFs), a class of events first identified by Heise in which the fluence in the 2-30 keV energy band exceeds that in the 30-400 keV energy band We summarize recent HETE-2 and other results on the properties of XRFs. These results show that the properties of XRFs, X-ray-rich gamma-ray bursts (GRBs), and GRBs form a continuum, and thus provide evidence that all three kinds of bursts are closely related phenomena. As the most extreme burst population, XRFs provide severe constraints on burst models and unique insights into the structure of GRB jets, the GRB rate, and the nature of Type Ib/Ic supernovae. We briefly mention a number of the physical models that have been proposed to explain XRFs. We then consider two fundamentally different classes of phenomenological jet models: universal jet models, in which it is posited that all GRBs jets are identical and that differences in the observed properties of the bursts are due entirely to differences in the viewing angle; and variable-opening angle jet models, in which it is posited that GRB jets have a distribution of jet opening angles and that differences in the observed properties of the bursts are due to differences in the emissivity and spectra of jets having different opening angles. We consider three shapes far the emissivity as a function of the viewing angle θ ν from the axis of the jet: power law, top hat (or uniform) , and Gaussian (or Fisher). We then discuss the effect of relativistic beaming on each of these models. We show that observations can distinguish between these various models

VLT identification of the optical afterglow of the gamma-ray burst GRB000131 at z=4.50

DEFF Research Database (Denmark)

Andersen, M.I.; Hjorth, J.; Jesen, B.L.

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...... Angstrom. This places GRB 000131 at a redshift of 4.500 +/- 0.015. The inferred isotropic energy release in gamma rays alone was similar to 10(54) erg (depending on the assumed cosmology). The rapid power-law decay of the afterglow (index alpha = 2.25, similar to bursts with a prior break in the lightcurve...

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...... Angstrom. This places GRB 000131 at a redshift of 4.500 +/- 0.015. The inferred isotropic energy release in gamma rays alone was similar to 10(54) erg (depending on the assumed cosmology). The rapid power-law decay of the afterglow (index alpha = 2.25, similar to bursts with a prior break in the lightcurve...

Association between receptor protein-tyrosine phosphatase RPTPalpha and the Grb2 adaptor. Dual Src homology (SH) 2/SH3 domain requirement and functional consequences

DEFF Research Database (Denmark)

Su, J; Yang, L T; Sap, J

1996-01-01

domain in Grb2 (, ). We show here that association of Grb2 with RPTPalpha also involves a critical function for the C-terminal SH3 domain of Grb2. Furthermore, Grb2 SH3 binding peptides interfere with RPTPalpha-Grb2 association in vitro, and the RPTPalpha protein can dissociate the Grb2-Sos complex...... in vivo. These observations constitute a novel mode of Grb2 association and suggest a model in which association with a tyrosine-phosphorylated protein restricts the repertoire of SH3 binding proteins with which Grb2 can simultaneously interact. The function of the Tyr798 tyrosine phosphorylation/Grb2...... binding site in RPTPalpha was studied further by expression of wild type or mutant RPTPalpha proteins in PC12 cells. In these cells, wild type RPTPalpha interferes with acidic fibroblast growth factor-induced neurite outgrowth; this effect requires both the catalytic activity and the Grb2 binding Tyr798...

Spectro-photometric study of the GRB 030329 host galaxy

International Nuclear Information System (INIS)

Gorosabel, J.; Ramirez, D. Perez

2005-01-01

In this study we present optical/near-infrared (NIR) broad band photometry and optical spectroscopic observations of the GRB 030329 host galaxy. The Spectral Energy Distribution (SED) of the host is consistent with a starburst galaxy template with a dominant stellar population age of ∼ 150 Myr and an extinction A ν ∼ 0.6. Analysis of the spectral emission lines shows that the host is likely a low metallicity galaxy. Two independent diagnostics, based on the restframe UV continuum and the [OII] line flux, provide a consistent unextincted star formation rate of SFRN ∼ 0.6 Myr -1 . The low absolute magnitude of the host (M B ∼ -16.5) implies a high specific star formation rate value, SSFR ≅ 34 Myr -1 (L/L) -1

The Fermi-GBM Gamma-Ray Burst Catalogs: The First Six Years

Directory of Open Access Journals (Sweden)

Bissaldi E.

2017-01-01

Full Text Available Since its launch in 2008, the Fermi Gamma-ray Burst Monitor (GBM has triggered and located on average approximately two gamma-ray bursts (GRBs every three days. Here we present the main results from the latest two catalogs provided by the Fermi-GBM science team, namely the third GBM GRB catalog [1] and the first GBM time-resolved spectral catalog [2]. The intention of the GBM GRB catalog is to provide information to the community on the most important observables of the GBM detected bursts. It comprises 1405 triggers identified as GRBs. For each one, location and main characteristics of the prompt emission, the duration, the peak flux and the fluence are derived. The GBM time-resolved spectral catalog presents high-quality time-resolved spectral analysis with high temporal and spectral resolution of the brightest bursts observed by Fermi GBM in a shorter period than the former catalog, namely four years. It comprises 1491 spectra from 81 bursts. Distributions of parameters, statistics of the parameter populations, parameter-parameter and parameter-uncertainty correlations, and their exact values are obtained.

Preparation of crystals for characterizing the Grb7 SH2 domain before and after complex formation with a bicyclic peptide antagonist.

Science.gov (United States)

Ambaye, Nigus D; Gunzburg, Menachem J; Traore, Daouda A K; Del Borgo, Mark P; Perlmutter, Patrick; Wilce, Matthew C J; Wilce, Jacqueline A

2014-02-01

Human growth factor receptor-bound protein 7 (Grb7) is an adapter protein involved in cell growth, migration and proliferation. It is now recognized that Grb7 is an emerging therapeutic target in specific cancer subtypes. Recently, the discovery of a bicyclic peptide inhibitor that targets the Grb7 SH2 domain, named G7-B1, was reported. In an attempt to probe the foundation of its interaction with Grb7, the crystallization and preliminary data collection of both the apo and G7-B1-bound forms of the Grb7 SH2 domain are reported here. Diffraction-quality crystals were obtained using the hanging-drop vapour-diffusion method. After several rounds of microseeding, crystals of the apo Grb7 SH2 domain were obtained that diffracted to 1.8 Å resolution, while those of the G7-B1-Grb7 SH2 domain complex diffracted to 2.2 Å resolution. The apo Grb7 SH2 domain crystallized in the trigonal space group P63, whereas the G7-B1-Grb7 SH2 domain complex crystallized in the monoclinic space group P21. The experimental aspects of crystallization, crystal optimization and data collection and the preliminary data are reported.

The Infrared Camera for RATIR, a Rapid Response GRB Followup Instrument

Science.gov (United States)

Rapchun, David A.; Alardin, W.; Bigelow, B. C.; Bloom, J.; Butler, N.; Farah, A.; Fox, O. D.; Gehrels, N.; Gonzalez, J.; Klein, C.; Kutyrev, A. S.; Lotkin, G.; Morisset, C.; Moseley, S. H.; Richer, M.; Robinson, F. D.; Samuel, M. V.; Sparr, L. M.; Tucker, C.; Watson, A.

2011-01-01

RATIR (Reionization and Transients Infrared instrument) will be a hybrid optical/near IR imager that will utilize the "J-band dropout" to rapidly identify very high redshift (VHR) gamma-ray bursts (GRBs) from a sample of all observable Swift bursts. Our group at GSFC is developing the instrument in collaboration with UC Berkeley (UCB) and University of Mexico (UNAM). RATIR has both a visible and IR camera, which give it access to 8 bands spanning visible and IR wavelengths. The instrument implements a combination of filters and dichroics to provide the capability of performing photometry in 4 bands simultaneously. The GSFC group leads the design and construction of the instrument's IR camera, equipped with two HgCdTe 2k x 2k Teledyne detectors. The cryostat housing these detectors is cooled by a mechanical cryo-compressor, which allows uninterrupted operation on the telescope. The host 1.5-m telescope, located at the UNAM San Pedro Martir Observatory, Mexico, has recently undergone robotization, allowing for fully automated, continuous operation. After commissioning in the spring of 2011, RATIR will dedicate its time to obtaining prompt follow-up observations of GRBs and identifying VHR GRBs, thereby providing a valuable tool for studying the epoch of reionization.

GRB060117: reverse and forward shock solution

Czech Academy of Sciences Publication Activity Database

Jelínek, M.; Prouza, Michael; Kubánek, K.; Hudec, René; Nekola, Martin; Řídký, Jan; Grygar, Jiří

2006-01-01

Roč. 121, č. 12 (2006), s. 1495-1496 ISSN 1594-9982. [Swift and GRBs: Unveiling the Relativistic Universe. Venice, 05.06.2006-09.06.2006] R&D Projects: GA AV ČR IAA3003206 Institutional research plan: CEZ:AV0Z10030501; CEZ:AV0Z10100502 Keywords : gamma-rays * gamma-ray bursts Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.351, year: 2006

Formation of Shc-Grb2 complexes is necessary to induce neoplastic transformation by overexpression of Shc proteins

DEFF Research Database (Denmark)

Salcini, A E; McGlade, J; Pelicci, G

1994-01-01

The mammalian SHC gene encodes three overlapping proteins which all contain a carboxy-terminal SH2 domain. Shc proteins are phosphorylated on tyrosine by a variety of receptor and cytoplasmic tyrosine kinases. Phosphorylated Shc proteins form a complex with the SH2-SH3 containing Grb2 protein which...... of Grb2 to Shc proteins requires phosphorylation of Shc at Tyr317, which lies within the high affinity binding motif for the Grb2 SH2 domain, pYVNV, where Asn at the +2 position is crucial for complex formation. In vivo, Tyr317 is the major, but not the only, site for Shc phosphorylation, and is the sole...... aminoterminal deletion, but retain the Tyr317 site and the SH2 domain conserve the capacity to be phosphorylated, to bind to Grb2 and to induce cell transformation. These data indicate that the formation of the Shc-Grb2 complex is a crucial event in the transformation induced by overexpression of Shc...

miR-411-5p inhibits proliferation and metastasis of breast cancer cell via targeting GRB2

International Nuclear Information System (INIS)

Zhang, Yunda; Xu, Guoxing; Liu, Gang; Ye, Yongzhi; Zhang, Chuankai; Fan, Chuannan; Wang, Haibin; Cai, Huali; Xiao, Rui; Huang, Zhengjie; Luo, Qi

2016-01-01

miR-411-5p (previously called miR-411) is severely involved in human diseases, however, the relationship between miR-411-5p and breast cancer has not been investigated thoroughly. Here, we found that the expression of miR-411-5p was downregulated in breast cancer tissues compared with their matched adjacent non-neoplastic tissues. In addition, the expression of miR-411-5p was also lower in breast cancer cell lines in contrast with MCF-10A. Moreover, we investigated the target and mechanism of miR-411-5p in breast cancer using mimic and inhibitor, and demonstrated the involvement of GRB2 and Ras activation. Ectopic expression of miR-411-5p suppressed the breast cancer cell proliferation, migration and invasion while low expression of miR-411-5p exhibited the opposite effect. Furthermore, GRB2 was demonstrated to be significantly overexpressed in breast cancer tissues compared with normal tissues, and low expression of GRB2 had a longer overall survival compared with high expression of GRB2 in breast cancer. In general, our study shed light on the miR-411-5p related mechanism in the progression of breast cancer and, miR-411-5p/GRB2/Ras axis is potential to be molecular target for breast cancer therapy. - Highlights: • miR-411-5p is downregulated in breast cancer tissues and cell lines. • miR-411-5p inhibits breast cancer cells growth, migration and invasion in vitro. • GRB2 is a direct target of miR-411-5p in breast cancer. • GRB2 is overexpressed in breast cancer and associates with disease outcome. • miR-411-5p suppresses breast cancer progression though GRB2-SOS-Ras pathway.

miR-411-5p inhibits proliferation and metastasis of breast cancer cell via targeting GRB2

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yunda [Department of Gastrointestinal Surgery, First Affiliated Hospital of Xiamen University, Xiamen 361003 (China); State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen 361102 (China); Xu, Guoxing [Department of Gastrointestinal Surgery, First Affiliated Hospital of Xiamen University, Xiamen 361003 (China); Department of Gastrointestinal Surgery, First Clinical Medical College of Fujian Medical University, Fuzhou 350005 (China); Liu, Gang; Ye, Yongzhi [Department of Gastrointestinal Surgery, First Affiliated Hospital of Xiamen University, Xiamen 361003 (China); Zhang, Chuankai [Department of Gastrointestinal Surgery, First Affiliated Hospital of Xiamen University, Xiamen 361003 (China); State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen 361102 (China); Fan, Chuannan [State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen 361102 (China); Wang, Haibin; Cai, Huali; Xiao, Rui [Department of Gastrointestinal Surgery, First Affiliated Hospital of Xiamen University, Xiamen 361003 (China); Department of Gastrointestinal Surgery, First Clinical Medical College of Fujian Medical University, Fuzhou 350005 (China); Huang, Zhengjie, E-mail: huangzhengjie@xmu.edu.cn [Department of Gastrointestinal Surgery, First Affiliated Hospital of Xiamen University, Xiamen 361003 (China); Department of Gastrointestinal Surgery, First Clinical Medical College of Fujian Medical University, Fuzhou 350005 (China); Luo, Qi, E-mail: luoqixmzsh@126.com [Department of Gastrointestinal Surgery, First Affiliated Hospital of Xiamen University, Xiamen 361003 (China); Department of Gastrointestinal Surgery, First Clinical Medical College of Fujian Medical University, Fuzhou 350005 (China)

2016-08-05

miR-411-5p (previously called miR-411) is severely involved in human diseases, however, the relationship between miR-411-5p and breast cancer has not been investigated thoroughly. Here, we found that the expression of miR-411-5p was downregulated in breast cancer tissues compared with their matched adjacent non-neoplastic tissues. In addition, the expression of miR-411-5p was also lower in breast cancer cell lines in contrast with MCF-10A. Moreover, we investigated the target and mechanism of miR-411-5p in breast cancer using mimic and inhibitor, and demonstrated the involvement of GRB2 and Ras activation. Ectopic expression of miR-411-5p suppressed the breast cancer cell proliferation, migration and invasion while low expression of miR-411-5p exhibited the opposite effect. Furthermore, GRB2 was demonstrated to be significantly overexpressed in breast cancer tissues compared with normal tissues, and low expression of GRB2 had a longer overall survival compared with high expression of GRB2 in breast cancer. In general, our study shed light on the miR-411-5p related mechanism in the progression of breast cancer and, miR-411-5p/GRB2/Ras axis is potential to be molecular target for breast cancer therapy. - Highlights: • miR-411-5p is downregulated in breast cancer tissues and cell lines. • miR-411-5p inhibits breast cancer cells growth, migration and invasion in vitro. • GRB2 is a direct target of miR-411-5p in breast cancer. • GRB2 is overexpressed in breast cancer and associates with disease outcome. • miR-411-5p suppresses breast cancer progression though GRB2-SOS-Ras pathway.

Testing the E(sub peak)-E(sub iso) Relation for GRBs Detected by Swift and Suzaku-WAM

Science.gov (United States)

Krimm, H. A.; Yamaoka, K.; Sugita, S.; Ohno, M.; Sakamoto, T.; Barthelmy, S. D.; Gehrels, N.; Hara, R.; Onda, K.; Sato, G.;

A Large Catalog of Multiwavelength GRB Afterglows. I. Color Evolution and Its Physical Implication

Science.gov (United States)

Li, Liang; Wang, Yu; Shao, Lang; Wu, Xue-Feng; Huang, Yong-Feng; Zhang, Bing; Ryde, Felix; Yu, Hoi-Fung

2018-02-01

The spectrum of gamma-ray burst (GRB) afterglows can be studied with color indices. Here, we present a large comprehensive catalog of 70 GRBs with multiwavelength optical transient data on which we perform a systematic study to find the temporal evolution of color indices. We categorize them into two samples based on how well the color indices are evaluated. The Golden sample includes 25 bursts mostly observed by GROND, and the Silver sample includes 45 bursts observed by other telescopes. For the Golden sample, we find that 96% of the color indices do not vary over time. However, the color indices do vary during short periods in most bursts. The observed variations are consistent with effects of (i) the cooling frequency crossing the studied energy bands in a wind medium (43%) and in a constant-density medium (30%), (ii) early dust extinction (12%), (iii) transition from reverse-shock to forward-shock emission (5%), or (iv) an emergent SN emission (10%). We also study the evolutionary properties of the mean color indices for different emission episodes. We find that 86% of the color indices in the 70 bursts show constancy between consecutive ones. The color index variations occur mainly during the late GRB–SN bump, the flare, and early reverse-shock emission components. We further perform a statistical analysis of various observational properties and model parameters (spectral index {β }o{CI}, electron spectral indices p CI, etc.) using color indices. Overall, we conclude that ∼90% of colors are constant in time and can be accounted for by the simplest external forward-shock model, while the varying color indices call for more detailed modeling.

Testing the anisotropy in the angular distribution of Fermi/GBM gamma-ray bursts

Science.gov (United States)

Tarnopolski, M.

2017-12-01

Gamma-ray bursts (GRBs) were confirmed to be of extragalactic origin due to their isotropic angular distribution, combined with the fact that they exhibited an intensity distribution that deviated strongly from the -3/2 power law. This finding was later confirmed with the first redshift, equal to at least z = 0.835, measured for GRB970508. Despite this result, the data from CGRO/BATSE and Swift/BAT indicate that long GRBs are indeed distributed isotropically, but the distribution of short GRBs is anisotropic. Fermi/GBM has detected 1669 GRBs up to date, and their sky distribution is examined in this paper. A number of statistical tests are applied: nearest neighbour analysis, fractal dimension, dipole and quadrupole moments of the distribution function decomposed into spherical harmonics, binomial test and the two-point angular correlation function. Monte Carlo benchmark testing of each test is performed in order to evaluate its reliability. It is found that short GRBs are distributed anisotropically in the sky, and long ones have an isotropic distribution. The probability that these results are not a chance occurrence is equal to at least 99.98 per cent and 30.68 per cent for short and long GRBs, respectively. The cosmological context of this finding and its relation to large-scale structures is discussed.

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.

iPTF17cw: An Engine-driven Supernova Candidate Discovered Independent of a Gamma-Ray Trigger

International Nuclear Information System (INIS)

Corsi, A.; Palliyaguru, N. T.; Cenko, S. B.; Singer, L. P.; Kutyrev, A.; Kasliwal, M. M.; Kulkarni, S. R.; Blagorodnova, N.; Kupfer, T.; Vedantham, H.; Quimby, R.; Frail, D. A.; Goldstein, A. M.; Connaughton, V.; Perley, D. A.; Copperwheat, C. M.; Piascik, A. S.; Steele, I. A.; Fremling, C.; Taddia, F.

2017-01-01

We present the discovery, classification, and radio-to-X-ray follow-up observations of iPTF17cw, a broad-lined (BL) type Ic supernova (SN) discovered by the intermediate Palomar Transient Factory (iPTF). Although it is unrelated to the gravitational wave trigger, this SN was discovered as a happy by-product of the extensive observational campaign dedicated to the follow-up of Advanced LIGO event GW 170104. The spectroscopic properties and inferred peak bolometric luminosity of iPTF17cw are most similar to the gamma-ray-burst (GRB)-associated SN, SN 1998bw, while the shape of the r -band light curve is most similar to that of the relativistic SN, SN 2009bb. Karl G. Jansky Very Large Array (VLA) observations of the iPTF17cw field reveal a radio counterpart ≈10 times less luminous than SN 1998bw, and with a peak radio luminosity comparable to that of SN 2006aj/GRB 060218 and SN 2010bh/GRB 100316D. Our radio observations of iPTF17cw imply a relativistically expanding outflow. However, further late-time observations with the VLA in its most extended configuration are needed to confirm fading of the iPTF17cw radio counterpart at all frequencies. X-ray observations carried out with Chandra reveal the presence of an X-ray counterpart with a luminosity similar to that of SN 2010bh/GRB 100316D. Searching the Fermi catalog for possible γ -rays reveals that GRB 161228B is spatially and temporally compatible with iPTF17cw. The similarity to SN 1998bw and SN 2009bb, the radio and X-ray detections, and the potential association with GRB 161228B all point to iPTF17cw being a new candidate member of the rare sample of optically discovered engine-driven BL-Ic SNe associated with relativistic ejecta.

iPTF17cw: An Engine-driven Supernova Candidate Discovered Independent of a Gamma-Ray Trigger

Energy Technology Data Exchange (ETDEWEB)

Corsi, A.; Palliyaguru, N. T. [Department of Physics and Astronomy, Texas Tech University, Box 1051, Lubbock, TX 79409-1051 (United States); Cenko, S. B.; Singer, L. P.; Kutyrev, A. [Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kasliwal, M. M.; Kulkarni, S. R.; Blagorodnova, N.; Kupfer, T.; Vedantham, H. [Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Quimby, R. [Department of Astronomy/Mount Laguna Observatory, San Diego State University, San Diego, CA 92182 (United States); Frail, D. A. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Goldstein, A. M.; Connaughton, V. [Universities Space Research Association, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Perley, D. A.; Copperwheat, C. M.; Piascik, A. S.; Steele, I. A. [Astrophysics Research Institute, Liverpool John Moores University, IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool, L3 5RF (United Kingdom); Fremling, C.; Taddia, F., E-mail: alessandra.corsi@ttu.edu [Oskar Klein Centre, Department of Astronomy, Stockholm University, Albanova University Centre, SE-106 91 Stockholm (Sweden); and others

2017-09-20

We present the discovery, classification, and radio-to-X-ray follow-up observations of iPTF17cw, a broad-lined (BL) type Ic supernova (SN) discovered by the intermediate Palomar Transient Factory (iPTF). Although it is unrelated to the gravitational wave trigger, this SN was discovered as a happy by-product of the extensive observational campaign dedicated to the follow-up of Advanced LIGO event GW 170104. The spectroscopic properties and inferred peak bolometric luminosity of iPTF17cw are most similar to the gamma-ray-burst (GRB)-associated SN, SN 1998bw, while the shape of the r -band light curve is most similar to that of the relativistic SN, SN 2009bb. Karl G. Jansky Very Large Array (VLA) observations of the iPTF17cw field reveal a radio counterpart ≈10 times less luminous than SN 1998bw, and with a peak radio luminosity comparable to that of SN 2006aj/GRB 060218 and SN 2010bh/GRB 100316D. Our radio observations of iPTF17cw imply a relativistically expanding outflow. However, further late-time observations with the VLA in its most extended configuration are needed to confirm fading of the iPTF17cw radio counterpart at all frequencies. X-ray observations carried out with Chandra reveal the presence of an X-ray counterpart with a luminosity similar to that of SN 2010bh/GRB 100316D. Searching the Fermi catalog for possible γ -rays reveals that GRB 161228B is spatially and temporally compatible with iPTF17cw. The similarity to SN 1998bw and SN 2009bb, the radio and X-ray detections, and the potential association with GRB 161228B all point to iPTF17cw being a new candidate member of the rare sample of optically discovered engine-driven BL-Ic SNe associated with relativistic ejecta.

On the existence of a luminosity threshold of GRB jets in massive stars

Science.gov (United States)

Aloy, M. A.; Cuesta-Martínez, C.; Obergaulinger, M.

2018-05-01

Motivated by the many associations of γ-ray bursts (GRBs) with energetic supernova (SN) explosions, we study the propagation of relativistic jets within the progenitor star in which a SN shock wave may be launched briefly before the jets start to propagate. Based on analytic considerations and verified with an extensive set of 2D axisymmetric relativistic hydrodynamic simulations, we have estimated a threshold intrinsic jet luminosity, L_j^thr, for successfully launching a jet. This threshold depends on the structure of the progenitor and, thus, it is sensitive to its mass and to its metallicity. For a prototype host of cosmological long GRBs, a low-metallicity star of 35 M⊙, it is L_j^thr˜eq 1.35× 10^{49} erg s-1. The observed equivalent isotropic γ-ray luminosity, L_{γ ,iso,BO} ˜eq 4 ɛ _γ L_j θ _BO^{-2}, crucially depends on the jet opening angle after breakout, θBO, and on the efficiency for converting the intrinsic jet luminosity into γ-radiation, ɛγ. Highly energetic jets can produce low-luminosity events if either their opening angle after the breakout is large, which is found in our models, or if the conversion efficiency of kinetic and internal energy into radiation is low enough. Beyond this theoretical analysis, we show how the presence of a SN shock wave may reduce this luminosity threshold by means of numerical simulations. We foresee that the high-energy transients released by jets produced near the luminosity threshold will be more similar to llGRBs or XRFs than to GRBs.

A NEW LUMINOSITY RELATION FOR GAMMA-RAY BURSTS AND ITS IMPLICATION