Hyper Velocity Stars and the Restricted Parabolic 3-body Problem (2009)
Sari, Re'em, Kobayashi, Shiho, Rossi, Elena M.
Motivated by detections of hypervelocity stars that may originate from the Galactic Center, we revist the problem of a binary disruption by a passage near a much more massive point mass. The six...
Ando, Masaki, Kawamura, Seiji, Sato, Shuichi, Nakamura, Takashi, Tsubono, Kimio, Araya, Akito, ...
DECIGO pathfinder (DPF) is a milestone satellite mission for DECIGO (DECi-hertz Interferometer Gravitational wave Observatory), which is a future space gravitational wave antenna. DECIGO is expected...
Optical flashes, reverse shocks and magnetization (2009)
Gomboc, Andreja, Kobayashi, Shiho, Mundell, Carole G., Guidorzi, Cristiano, Melandri, Andrea, Steele, Iain A., ...
Despite the pre-Swift expectation that bright optical flashes from reverse shocks would be prevalent in early-time afterglow emission, rapid response observations show this not to be the case....
Ando, Masaki, Kawamura, Seiji, Nakamura, Takashi, Tsubono, Kimio, Tanaka, Takahiro, Funaki, Ikkoh, ...
DECIGO pathfinder (DPF) is a milestone satellite mission for DECIGO (DECi-hertz Interferometer Gravitational wave Observatory) which is a future space gravitational wave antenna. DECIGO is expected...
The Japanese space gravitational wave antenna; DECIGO (2008)
Kawamura, Seiji, Ando, Masaki, Nakamura, Takashi, Tsubono, Kimio, Tanaka, Takahiro, Funaki, Ikkoh, ...
DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future Japanese space gravitational wave antenna. DECIGO is expected to open a new window of observation for gravitational...
Early Optical Polarization of a Gamma Ray Burst Afterglow (2007)
Mundell, Carole G., Steele, Iain A., Smith, Robert J., Kobayashi, Shiho, Melandri, Andrea, Guidorzi, Cristiano, ...
We report the optical polarization of a gamma ray burst (GRB) afterglow, obtained 203 seconds after the initial burst of gamma rays from GRB 060418, using a ring polarimeter on the robotic Liverpool...
Mergers of Black Hole -- Neutron Star binaries. I. Methods and First Results (2007)
Rantsiou, Emmanouela, Kobayashi, Shiho, Laguna, Pablo, Rasio, Frederic
We use a 3-D relativistic SPH (Smoothed Particle Hydrodynamics) code to study mergers of black hole -- neutron star (BH--NS) binary systems with low mass ratios, adopting $M_{NS}/M_{BH} \simeq 0.1$...
GRB Radiative Efficiencies Derived from the Swift Data: GRBs vs. XRFs, Long vs. Short (2006)
Zhang, Bing, Liang, Enwei, Page, Kim L., Grupe, Dirk, Zhang, Bin-Bin, Barthelmy, Scott D., ...
We systematically analyze the prompt emission and the early afterglow data of a sample of 31 GRBs detected by {\em Swift} before September 2005, and estimate the GRB radiative efficiency. BAT's...
The early X-ray emissions from GRBs (2006)
O'Brien, Paul T., Willingale, R., Osborne, Julian P., Goad, Michael R., Page, Kim L., Vaughan, Simon, ...
The definitive version of this paper, with enhancements, is available from http://www.journals.uchicago.edu/ApJ/journal/issues/ApJ/v647n2/64315/64315.html
The Onset of Gamma-Ray Burst Afterglow (2006)
We discuss the reference time t_0 of afterglow light curves in the context of the standard internal-external shock model. The decay index of early afterglow is very sensitive to the reference time...
Liang, E.W., Zhang, B., O'Brien, Paul T., Willingale, R., Angelini, Lorella, Burrows, David N., ...
The definitive version of this paper, with enhancements, is available from http://www.journals.uchicago.edu/ApJ/journal/issues/ApJ/v646n1/64620/64620.html
The Swift X-ray flaring afterglow of GRB 050607 (2006)
Pagani, Claudio, Morris, David C., Kobayashi, Shiho, Sakamoto, Takanori, Falcone, Abraham D., Moretti, Alberto, ...
The definitive version of this paper is available at http://www.journals.uchicago.edu/ApJ/journal/issues/ApJ/v645n2/64323/64323.html
The Swift X-ray flaring afterglow of GRB 050607 (2006)
Pagani, Claudio, Morris, David C., Kobayashi, Shiho, Sakamoto, Takanori, Falcone, Abraham D., Moretti, Alberto, ...
The unique capability of the Swift satellite to perform a prompt and autonomous slew to a newly detected Gamma-Ray Burst (GRB) has yielded the discovery of interesting new properties of GRB X-ray...
Late-time X-ray flares during GRB afterglows: extended internal engine activity (2006)
Falcone, Abraham D., Burrows, David N., Romano, Patrizia, Kobayashi, Shiho, Lazzati, D., Zhang, B., ...
Also available via arxiv.org.
Swift observations of the prompt X-ray emission and afterglow from GRB050126 and GRB050219A (2006)
Goad, Michael R., Tagliaferri, Gianpiero, Page, Kim L., Moretti, Alberto, Osborne, Julian P., Kobayashi, Shiho, ...
The definitive version of this paper is available from www.edpsciences.org/aa.
Swift and XMM-Newton observations of the dark GRB 050326 (2006)
Moretti, Alberto, De Luca, A., Malesani, D., Campana, Sergio, Tiengo, A., Cucchiara, A., ...
The definitive version of this paper is available from www.edpsciences.org/aa
X-ray flare in XRF 050406: evidence for prolonged engine activity (2006)
Romano, Patrizia, Moretti, Alberto, Banat, P.L., Burrows, David N., Campana, Sergio, Chincarini, Guido, ...
The definitive version of this paper is available from www.edpsciences.org/aa
The early X-ray emission from GRBs (2006)
O'Brien, Paul T., Willingale, R., Osborne, Julian P., Goad, Michael R., Page, Kim L., Vaughan, Simon A., ...
Zhang, Bing, Fan, Y. Z., Dyks, Jaroslaw, Kobayashi, Shiho, Meszaros, Peter, Burrows, David N., ...
(Abridged) The Swift X-Ray Telescope (XRT) reveals some interesting features of early X-ray afterglows, including a distinct rapidly decaying component preceding the conventional afterglow component...
Inverse Compton X-ray Flare from GRB Reverse Shock (2005)
Kobayashi, Shiho, Zhang, Bing, Meszaros, Peter, Burrows, David N.
We study synchrotron self-inverse Compton radiation from a reverse-shocked fireball. If the inverse Compton process dominates the cooling of shocked electrons, an X-ray flare produced by the first...
Reply to Lyutikov's comments on Zhang & Kobayashi (2005) (2005)
Lyutikov (astro-ph/0503505) raised a valid point that for shock deceleration of a highly magnetized outflow, the fate of the magnetic fields after shock crossing should be considered. However, his...
TeV-PeV Neutrinos from Giant Flares of Magnetars and the Case of SGR 1806-20 (2005)
Ioka, Kunihito, Razzaque, Soebur, Kobayashi, Shiho, Meszaros, Peter
We estimate the high energy neutrino flux from the giant flare of SGR 1806-20 on December 27, 2004, which irradiated Earth with a gamma-ray flux ~10^4 times larger than the most luminous gamma-ray...
Relativistic SPH Calculations of Compact Binary Mergers (2005)
Rasio, Frederic, Faber, Joshua, Kobayashi, Shiho, Laguna, Pablo
We review recent progress in understanding the hydrodynamics of compact binary mergers using relativistic smoothed particle hydrodynamics (SPH) codes. Recent results are discussed for both double...
Swift XRT and VLT Observations of the Afterglow of GRB 041223 (2005)
Burrows, David N., Hill, Joanne E., Chincarini, Guido, Tagliaferri, Gianpiero, Campana, Sergio, Moretti, Alberto, ...
The Swift Gamma-Ray Burst Explorer, launched on 2004 November 20, is a multiwavelength, autonomous, rapid-slewing observatory for gamma-ray burst (GRB) astronomy. On 2004 December 23, during the...
An unexpectedly rapid decline in the X-ray afterglow emission of long gamma-ray bursts (2005)
Tagliaferri, Gianpiero, Goad, Michael R., Chincarini, Guido, Moretti, Alberto, Campana, Sergio, Burrows, David N., ...
A short gamma-ray burst apparently associated with an elliptical galaxy at redshift 0.225 (2005)
Gehrels, Neil, Sarazin, C.L., O'Brien, Paul T., Zhang, B., Barbier, L., Barthelmy, Scott D., ...
Bulk Compton Emission in the GRB Internal Shock Model (2004)
We investigate the role of the bulk Compton-scattering process in the internal shock model. We numerically show that the radiation field created by internal shocks does not affect the efficiency of...
Optical afterglows of short Gamma-ray Bursts and GRB 040924 (2004)
Fan, Y. Z., Zhang, Bing, Kobayashi, Shiho, Meszaros, Peter
Short-duration Gamma-ray bursts (GRBs) (\leq 2{\rm s}) have remained a mystery due to the lack of afterglow detection until recently. The models to interpret short GRBs invoke distinct progenitor...
Ioka, Kunihito, Kobayashi, Shiho, Zhang, Bing
We show that simple kinematic arguments can give limits on the timescale and amplitude of variabilities in gamma-ray burst (GRB) afterglows, especially when the variability timescale is shorter than...
Extended GeV-TeV Emission around Gamma-Ray Burst Remnants, and the Case of W49B (2004)
Ioka, Kunihito, Kobayashi, Shiho, Meszaros, Peter
We investigate the high-energy photon emission around Gamma-Ray Burst (GRB) remnants caused by ultrahigh-energy cosmic rays (UHECRs) from the GRBs. We apply the results to the recent report that the...
Gravitational Wave and X-ray Signals from Stellar Disruption by a Massive Black Hole (2004)
Kobayashi, Shiho, Laguna, Pablo, Phinney, E. Sterl, Meszaros, Peter
Gravitational waves and X-ray flares are expected from tidal disruption of stars by a massive black hole. Using a relativistic smoothed particle hydrodynamics code, we investigate the fate of main...
Evidence suggests that the gamma-ray burst (GRB) ejecta is likely magnetized, although the degree of magnetization of the ejecta is unknown. We derive a rigorous analytical solution for the...
Zhang, Bing, Kobayashi, Shiho, Meszaros, Peter, Lloyd-Ronning, Nicole M., Dai, Xinyu
Two separate topics are discussed. (1) We describe the classifications of the long GRB early afterglow lightcurves within the framework of the fireball shock model, focusing on the interplay between...
A Characteristic Dense Environment or Wind Signature in Prompt GRB Afterglows (2003)
Kobayashi, Shiho, Meszaros, Peter, Zhang, Bing
We discuss the effects of synchrotron self-absorption in the prompt emission from the reverse shock of GRB afterglows occurring in a dense environment, such as the wind of a massive stellar...
Early Optical Afterglows from Wind-Type Gamma-Ray Bursts (2003)
We study prompt optical emission from reverse shocks in the wind-type gamma-ray bursts. The emission is evaluated in both the thick and thin shell regimes. We discuss the angular time delay effect...
Zhang, Bing, Kobayashi, Shiho, Meszaros, Peter
Early optical afterglows have been observed from GRB 990123, GRB 021004, and GRB 021211, which reveal rich emission features attributed to reverse shocks. It is expected that Swift will discover many...
Polarized Gravitational Waves from Gamma-Ray Bursts (2002)
Kobayashi, Shiho, Meszaros, Peter
Significant gravitational wave emission is expected from gamma-ray bursts arising from compact stellar mergers, and possibly also from bursts associated with fast-rotating massive stellar core...
GRB 021004: Reverse Shock Emission (2002)
We show that the re-brightening in the GRB 021004 optical afterglow light curve around ~ 0.1 day can be explained within the framework of the standard fireball model. The superposition of a forward...
Gravitational Radiation from Gamma-Ray Burst Progenitors (2002)
Kobayashi, Shiho, Meszaros, Peter
We study gravitational radiation from various proposed gamma-ray burst (GRB) progenitor models, in particular compact mergers and massive stellar collapses. These models have in common a high angular...
Luminosity and Variability of Collimated Gamma-ray Bursts (2001)
Kobayashi, Shiho, Ryde, Felix, MacFadyen, Andrew
Within the framework of the internal shock model, we study the luminosity and the variability in gamma-ray bursts from collimated fireballs. In particular we pay attention to the role of the...
Ultra Efficient Internal Shocks (2000)
Gamma-ray bursts are believed to originate from internal shocks which arise in an irregular relativistic wind. The process has been thought to be inefficient, converting only a few percent of the...
Light Curves of GRB Optical Flashes (2000)
The standard model of GRB afterglows assumes that relativistically expanding material is decelerating due to interaction with the surrounding medium. The afterglows are well described by the...
Optical flashes and radio flares in GRB afterglows: Numerical study (2000)
We numerically study the evolution of an adiabatic relativistic fireball interacting with an ambient uniform medium, both in the initial energy transfer stage and in its late evolution. It is shown...
Optical Flashes and Radio Flares in GRBs afterglow: Numerical Study (1999)
The strong optical flash observed by ROTSE, as well as the radio flare associated with GRB 990123 can be attributed to the emission of the fireball ejecta, initially heated by the reverse shock. We...
Hydrodynamics of a Relativistic Fireball: the Complete Evolution (1998)
Kobayashi, Shiho, Piran, Tsvi, Sari, Re'em
We study numerically the evolution of an adiabatic relativistic fireball expanding into a cold uniform medium. We follow the stages of initial free expansion and acceleration, coasting and then...
Can internal shocks produce the variability in GRBs? (1997)
Kobayashi, Shiho, Piran, Tsvi, Sari, Re'em
We discuss the possibility that gamma-ray bursts result from internal shocks in an ultra-relativistic matter. Using a simple model we calculate the temporal structure and we estimate the efficiency...
Kobayashi, Shiho, Sasaki, Shin, Suto, Yasushi
We performed a systematic and comprehensive estimate of the Hubble constant $H_0$ via the Sunyaev-Zel'dovich temperature decrement and the X-ray measurements for clusters up to the redshift...
Anderson Localization in the Sky and Cosmological Magnetic Field (1995)
Hosoya, Akio, Kobayashi, Shiho
We discuss the Anderson localization of electromagnetic fields in the fluctuating plasma induced by the gravitational density perturbation before the recombination time of the Universe. Randomly...
Angular two-point correlation functions for cosmological gamma-ray burst model (1994)
Kobayashi, Shiho, Sasaki, Shin, Suto, Yasushi
We compute the angular two-point correlation functions of the gamma-ray bursts at cosmological distances. Since the gamma-ray burst emission mechanism is not yet established, we simply assume that...