J. L. Racusin
A5073279263- Gamma-ray bursts and supernovae
- SAS software applications and methods
- Astronomical Observations and Instrumentation
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Astrophysics and Cosmic Phenomena
- Particle Detector Development and Performance
- Pulsars and Gravitational Waves Research
- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Dark Matter and Cosmic Phenomena
- Geophysics and Gravity Measurements
- Radio Astronomy Observations and Technology
- Nuclear Physics and Applications
- Solar and Space Plasma Dynamics
- Adaptive optics and wavefront sensing
- Statistical and numerical algorithms
- Neutrino Physics Research
- Inertial Sensor and Navigation
- Advanced X-ray and CT Imaging
- Planetary Science and Exploration
- Galaxies: Formation, Evolution, Phenomena
- Particle Accelerators and Free-Electron Lasers
- Spacecraft Design and Technology
- Microbial Metabolites in Food Biotechnology
Goddard Space Flight Center
2015-2024
Deleted Institution
2015-2024
University of Alabama in Huntsville
2021
University of Delaware
2021
Universities Space Research Association
2021
University of Wisconsin–Madison
2021
Catholic University of America
2021
George Washington University
2021
University of Maryland, Baltimore County
2021
Clemson University
2021
We present a homogeneous X-ray analysis of all 318 gamma-ray bursts detected by the telescope (XRT) on Swift satellite up to 2008 July 23; this represents largest sample GRB data published date. In Sections 2–3, we detail methods which Swift-XRT team has developed produce enhanced positions, light curves, hardness ratios and spectra presented in paper. Software using these continues create such products for new GRBs observed Swift-XRT. also web-based tools allowing users any object XRT, not...
We study the optical colors of 147,920 galaxies brighter than g* = 21, observed in five bands by Sloan Digital Sky Survey (SDSS) over ∼100 deg2 high Galactic latitude sky along celestial equator. The distribution g*-r* versus u*-g* color-color diagram is strongly bimodal, with an optimal color separator u*-r* 2.22. use visual morphology and spectral classification subsamples 287 500 galaxies, respectively, to show that two peaks correspond roughly early- (E, S0, Sa) late-type (Sb, Sc, Irr)...
On August 17, 2017 at 12:41:06 UTC the Fermi Gamma-ray Burst Monitor (GBM) detected and triggered on short gamma-ray burst GRB 170817A. Approximately 1.7 s prior to this GRB, Laser Interferometer Gravitational-Wave Observatory (LIGO) a binary compact merger candidate associated with GRB. This is first unambiguous coincident observation of gravitational waves electromagnetic radiation from single astrophysical source marks start gravitational-wave multi-messenger astronomy. We report GBM...
Context.Swift data are revolutionising our understanding of Gamma Ray Bursts. Since bursts fade rapidly, it is desirable to create and disseminate accurate light curves rapidly.
With an instantaneous view of 70% the sky, Fermi Gamma-ray Burst Monitor (GBM) is excellent partner in search for electromagnetic counterparts to gravitational wave (GW) events. GBM observations at time Laser Interferometer Gravitational-wave Observatory (LIGO) event GW150914 reveal presence a weak transient above 50 keV, 0.4~s after GW event, with false alarm probability 0.0022 (2.9$\sigma$). This lasting 1 s was not detected by any other instrument and does appear connected previously...
With the first direct detection of merging black holes in 2015, era gravitational wave (GW) astrophysics began. A complete picture compact object mergers, however, requires an electromagnetic (EM) counterpart. We report ultraviolet (UV) and X-ray observations by Swift Nuclear Spectroscopic Telescope ARray (NuSTAR) EM counterpart binary neutron star merger GW170817. The bright, rapidly fading emission indicates a high mass ($\approx0.03$ solar masses) wind-driven outflow with moderate...
We present a systematic temporal and spectral study of all Swift-X-ray Telescope observations gamma-ray burst (GRB) afterglows discovered between 2005 January 2007 December. After constructing fitting light curves spectra to power-law models, we classify the components each afterglow in terms canonical X-ray test them against closure relations forward shock models for variety parameter combinations. The are used identify potential jet breaks with characteristics including uniform model...
Abstract The Large Area Telescope (LAT) aboard the Fermi spacecraft routinely observes high-energy emission from gamma-ray bursts (GRBs). Here we present second catalog of LAT-detected GRBs, covering first 10 yr operations, 2008 to 2018 August 4. A total 186 GRBs are found; these, 91 show in range 30–100 MeV (17 which seen only this band) and 169 detected above 100 MeV. Most these sources were discovered by other instruments ( /GBM, Swift /BAT, AGILE, INTEGRAL ) or reported Interplanetary...
Abstract GRB 221009A has been referred to as the brightest of all time (BOAT). We investigate veracity this statement by comparing it with a half century prompt gamma-ray burst observations. This is ever detected measures peak flux and fluence. Unexpectedly, highest isotropic-equivalent total energy identified, while luminosity at ∼99th percentile known distribution. explore how such can be powered discuss potential implications for ultralong high-redshift bursts. By geometric extrapolation...
Abstract We report the discovery of GRB 221009A, highest flux gamma-ray burst (GRB) ever observed by Fermi Gamma-ray Burst Monitor (Fermi-GBM). This has continuous prompt emission lasting more than 600 s, which smoothly transitions to afterglow visible in Fermi-GBM energy range (8 keV–40 MeV), and total energetics higher any other sample. By using a variety new existing analysis techniques we probe spectral temporal evolution 221009A. find no prior trigger time ( t 0 ; 2022 October 9 at...
The Fermi Large Area Telescope (LAT) light curve repository (LCR) is a publicly available, continually updated library of gamma-ray curves variable Fermi-LAT sources generated over multiple timescales. LCR aims to provide publication-quality binned on timescales 3 days, 7 and 30 days for 1525 deemed in the source catalog first 10 years observations. consists through full likelihood analyses that model surrounding region, providing fluxes photon indices each time bin. intended as resource...
We present the first systematic investigation of morphological and timing properties flares in GRBs observed by Swift XRT. consider a large sample drawn from all detected Swift, INTEGRAL, HETE-2 prior to 2006 January 31, which had an XRT follow-up showed significant flaring. Our 33 includes long short, at low high redshift, total 69 flares. The strongest occur early phases, with clear anticorrelation between flare peak intensity time occurrence. Fitting each X-ray Gaussian model, we find...
GRB110721A was observed by the Fermi Gamma-ray Space Telescope using its two instruments Large Area (LAT) and Burst Monitor (GBM). The burst consisted of one major emission episode which lasted for ~24.5 seconds (in GBM) had a peak flux 5.7\pm0.2 x 10^{-5} erg/s/cm^2. time-resolved spectrum is best modeled with combination Band function blackbody spectrum. energy component initially 15\pm2 MeV, highest value ever detected in GRB. This measurement made possible combining GBM/BGO data LAT Low...
We present a comprehensive statistical analysis of Swift X-ray light curves gamma-ray bursts (GRBs) collecting data from more than 650 GRBs discovered by and other facilities. The unprecedented sample size allows us to constrain the rest-frame properties perspective, with particular reference intrinsic time-scales energetics different light-curve phases in common 0.3–30 keV energy band. Temporal variability episodes are also studied their constrained. Two fundamental questions drive this...
The Swift/XRT data of 179 GRBs (from 050124 to 070129) and the optical afterglow 57 pre- post-Swift are analyzed, in order systematically investigate jet-like breaks X-ray lightcurves. We find that not a single burst can be included ``Platinum'' sample, which satisfy all criteria jet break. By releasing one or more requirements define break, some candidates various degrees could identified. In band, 42 out 103 well-sampled lightcurves have decay slope post-break segment >1.5 (``Bronze''...
The All-sky Medium Energy Gamma-ray Observatory (AMEGO) is a probe class mission concept that will provide essential contributions to multimessenger astrophysics in the late 2020s and beyond. AMEGO combines high sensitivity 200 keV 10 GeV energy range with wide field of view, good spectral resolution, polarization sensitivity. Therefore, key study astrophysical objects have unique signatures gamma-ray regime, such as neutron star mergers, supernovae, flaring active galactic nuclei....
The All-sky Medium Energy Gamma-ray Observatory eXplorer (AMEGO-X) is designed to identify and characterize gamma rays from extreme explosions accelerators. main science themes include: supermassive black holes their connections neutrinos cosmic rays; binary neutron star mergers the relativistic jets they produce; ray particle acceleration sources including Galactic supernovae; continuous monitoring of other astrophysical events over full sky in this important energy range. AMEGO-X will...
Abstract We present James Webb Space Telescope (JWST) and Hubble (HST) observations of the afterglow GRB 221009A, brightest gamma-ray burst (GRB) ever observed. This includes first mid-IR spectra any GRB, obtained with JWST/Near Infrared Spectrograph (0.6–5.5 micron) Mid-Infrared Instrument (5–12 micron), 12 days after burst. Assuming that intrinsic spectral slope is a single power law, F ν ∝ − β , we obtain ≈ 0.35, modified by substantial dust extinction A V = 4.9. suggests above notional...
GRB observations with Swift produced the initially surprising result that many bursts have large, late-time X-ray flares. The flares were sometimes intense, had rapid rise and decay phases, occurred late relative to prompt phase. Many GRBs several flares, which overlapping. origin of can be investigated by comparing spectra during those afterglow initial emission. In this work we analyzed all significant from first 110 observed Swift. Significant (>3 σ ) found in 33 these GRBs, 77 detected....