Related papers: A thousand days after the merger: continued X-ray …
The Fermi Gamma-ray Burst Monitor reported the possible detection of the gamma-ray counterpart of a binary black hole merger event, GW150914. We show that the gamma-ray emission is caused by a relativistic outflow with Lorentz factor larger…
We report the discovery of extended X-ray emission around the powerful high-redshift quasar GB 1508+5714 at z=4.3, revealed in a long Chandra ACIS observation. The emission feature is 3-4 arcsec away from the quasar core, which corresponds…
The radio and X-rays that followed GW170817 increased gradually over $\sim~100$ days, resembling the radio flare predicted to arise from the interaction of a binary neutron star merger outflow with the ISM \citep{nakar2011}. Considering a…
GW170817 was the first detection of a binary neutron star merger via gravitational waves. The event was observed over a wide range of the electromagnetic spectrum, revealing a thermal kilonova dominating the optical signal during the first…
The binary neutron star merger event GW170817 was detected through both electromagnetic radiation and gravitational waves. Its afterglow emission may have been produced by either a narrow relativistic jet or an isotropic outflow. High…
The gamma-ray burst GB970508 was observed simultaneously by the Gamma Ray Burst Monitor (GRBM) and one of the X-ray Wide Field Cameras (WFC) aboard BeppoSAX. The latter provided a position within 1.9' radius. A series of follow-up…
An energetic $\rm \gamma$-ray burst (GRB), GRB 211211A, was observed on 2021 December 11 by the Neil Gehrels Swift Observatory. Despite its long duration, typically associated with bursts produced by the collapse of massive stars, the…
We present new imaging and spectral analysis of the recently discovered extended X-ray emission around the high magnetic field rotating radio transient RRAT J1819-1458. We used two Chandra observations performed for this object in 2008 May…
We report on the results of a four-year long X-ray monitoring campaign of the central 1.2 square degrees of our Galaxy, performed with Chandra and XMM-Newton between 2005 and 2008. Our study focuses on the properties of transient X-ray…
The electromagnetic radiation that followed the neutron star merger event GW170817 revealed that gamma-ray burst afterglows from jets misaligned with our line of sight exhibit a light curve with slowly rising flux. The slope of the rising…
We present multi-color optical and two-frequency radio observations of the bright SAX event, GRB 990510. The well-sampled optical decay, together with the radio observations are inconsistent with simple spherical afterglow models. The…
After nearly two years of quiescence, the soft gamma-ray repeater SGR 1900+14 again became burst-active on April 18 2001, when it emitted a large flare, preceded by few weak and soft short bursts. After having detected the X and gamma…
Many X-ray observations of GigaHertz Peaked Spectrum and Compact Steep Spectrum sources have been made with Chandra X-ray Observatory and XMM-Newton Observatory over the last few years. The X-ray spectra contribute the important information…
The mergers of compact binaries with at least one neutron star component are the potential leading sites of the production and ejection of $r$-process elements. Discoveries of galactic binary pulsars, short gamma-ray bursts, and…
Gravitational waves from a merger of two neutron stars (NSs) were discovered for the first time in GW170817, together with diverse electromagnetic (EM) counterparts. To make constraints on a relativistic jet from the NS merger, we calculate…
A long-standing paradigm in astrophysics is that collisions- or mergers- of two neutron stars (NSs) form highly relativistic and collimated outflows (jets) powering gamma-ray bursts (GRBs) of short (< 2 s) duration. However, the…
We present the results of our year-long afterglow monitoring of GW170817, the first binary neutron star (NS) merger detected by advanced LIGO and advanced Virgo. New observations with the Australian Telescope Compact Array (ATCA) and the…
We report Chandra observations of GW170817, the first neutron star-neutron star merger discovered by the joint LIGO-Virgo Collaboration, and the first direct detection of gravitational radiation associated with an electromagnetic…
We present calculations of the wide angle emission of short-duration gamma-ray bursts from compact binary merger progenitors. Such events are expected to be localized by their gravitational wave emission, fairly irrespective of the…
We report on optical, near-infrared and centimeter radio observations of GRB000418 which allow us to follow the evolution of the afterglow from 2 to 200 days after the gamma-ray burst. In modeling these broad-band data, we find that an…