H. A. Krimm
A5014137132- Gamma-ray bursts and supernovae
- SAS software applications and methods
- Astronomical Observations and Instrumentation
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- Microbial Metabolites in Food Biotechnology
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Astro and Planetary Science
- Particle Detector Development and Performance
- Geophysics and Gravity Measurements
- Solar and Space Plasma Dynamics
- Statistical and numerical algorithms
- Mechanics and Biomechanics Studies
- Particle Accelerators and Free-Electron Lasers
- Advanced X-ray and CT Imaging
- Adaptive optics and wavefront sensing
- Medical Imaging Techniques and Applications
- Nuclear Physics and Applications
- Inertial Sensor and Navigation
- Advanced Semiconductor Detectors and Materials
- Radio Astronomy Observations and Technology
- Superconducting Materials and Applications
- History and Developments in Astronomy
U.S. National Science Foundation
2016-2024
Universities Space Research Association
2010-2019
University of Maryland, Baltimore County
2009-2018
Goddard Space Flight Center
2008-2017
Deleted Institution
2010-2017
National Institute for Astrophysics
2005-2015
Los Alamos National Laboratory
2009-2011
University of Maryland, College Park
2009-2011
Institute of Space and Astronautical Science
2009-2011
The Ohio State University
2011
The Swift mission, scheduled for launch in 2004, is a multiwavelength observatory gamma-ray burst (GRB) astronomy. It first-of-its-kind autonomous rapid-slewing satellite transient astronomy and pioneers the way future rapid-reaction missions. will be far more powerful than any previous GRB observing 100 bursts yr-1 performing detailed X-ray UV/optical afterglow observations spanning timescales from 1 minute to several days after burst. objectives are (1) determine origin of GRBs, (2)...
Gamma-ray burst (GRB) afterglows have provided important clues to the nature of these massive explosive events, providing direct information on nearby environment and indirect central engine that powers burst. We report discovery two bright x-ray flares in GRB afterglows, including a giant flare comparable total energy itself, each peaking minutes after These strong, rapid imply engines bursts long periods activity, with strong internal shocks continuing for hundreds seconds gamma-ray...
We report the discovery by Swift hard X-ray monitor of transient source J2058.4+0516 (Sw J2058+05). Our multi-wavelength follow-up campaign uncovered a long-lived (duration ≳ months), luminous (LX, iso ≈ 3 × 1047 erg s−1) and radio (νLν, 1042 counterpart. The associated optical emission, however, from which we measure redshift 1.1853, is relatively faint, this not due to large amount dust extinction in host galaxy. Based on numerous similarities with recently discovered GRB 110328A/Swift...
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 observations of the early X-ray emission for a sample 40 gamma-ray bursts (GRBs) obtained using Swift satellite which narrow-field instruments were pointed at burst within 10 minutes trigger. Using data from Burst Alert and X-Ray Telescopes, we show that light curve can be well described by an exponential relaxes into power law, often with flares superimposed. The transition time between law provides physically defined timescale duration. In most breaks to shallower decay first...
We present the catalog of sources detected in first 22 months data from hard X-ray survey (14--195 keV) conducted with BAT coded mask imager on \swift satellite. The contains 461 above 4.8 sigma level BAT. High angular resolution for every source Swift XRT or archival have allowed associations to be made known counterparts other wavelength bands over 97% detections, including discovery ~30 galaxies previously unknown as AGN and several new Galactic sources. A total 266 are associated Seyfert...
We present the second Swift Burst Alert Telescope (BAT) catalog of gamma-ray bursts (GRBs), which contains 476 detected by BAT between 2004 December 19 and 2009 21. This (hereafter BAT2 catalog) presents burst trigger time, location, 90% error radius, duration, fluence, peak flux, time-averaged spectral parameters, time-resolved parameters measured BAT. In correlation study various observed extracted from prompt emission data, we distinguish among long-duration GRBs (L-GRBs), short-duration...
We present a detailed analysis of Swift multi-wavelength observations GRB 070110 and its remarkable afterglow. The early X-ray light curve, interpreted as the tail prompt emission, displays spectral evolution already seen in other gamma-ray bursts. optical afterglow shows shallow decay up to ~2 d after burst, which is not consistent with standard models. most intriguing feature very steep flux at ~20 ks ending an apparent plateau. abrupt drop curve rules out external shock origin plateau...
We present the first Swift Burst Alert Telescope (BAT) catalog of gamma-ray bursts (GRBs), which contains detected by BAT between 2004 December 19 and 2007 June 16. This (hereafter BAT1 catalog) burst trigger time, location, 90% error radius, duration, fluence, peak flux, time-averaged spectral parameters for each 237 GRBs, as measured BAT. The BAT-determined position reported here is within 1.75' X-Ray (XRT)-determined these GRBs. T90 T50 durations at 80 20 s, respectively. From...
The Crab Nebula is the only hard X-ray source in sky that both bright enough and steady to be easily used as a standard candle. As result, it has been normalization by most X-ray/gamma-ray telescopes. Although small-scale variations nebula are well known, since start of science operations Fermi Gamma-ray Burst Monitor (GBM) 2008 August, ∼7% (70 mCrab) decline observed overall flux 15–50 keV band, measured with Earth occultation technique. This independently confirmed ∼15–50 band three other...
We present an intensive radio and X-ray monitoring campaign on the 2009 outburst of Galactic black hole candidate binary H1743-322. With high angular resolution Very Long Baseline Array, we resolve jet ejection event measure proper motions ejecta relative to position compact core jets detected at beginning outburst. This allows us accurately couple moment when occurred with spectral timing signatures. find that signatures are best diagnostic in this outburst, which as variability began...
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 9.38. We present analyses BAT-detected for past 11 years up through GRB151027B. report summaries both temporal and spectral GRB characteristics using event data (i.e., each photon within approximately 250 s before 950 after BAT trigger time), discuss instrumental sensitivity selection effects detections. also explore...
We report on the intense burst ``forest'' recorded 2006 March 29 which lasted for ~30s. More than 40 bursts were detected both by BAT and XRT, seven of are rare intermediate flares (IFs): several times 10^{42} ergs released. The data used to carry out time-resolved spectroscopy in 14-100keV range down 8ms timescales. This unique dataset allowed us test magnetar model predictions such as magnetically trapped fireball twisted magnetosphere over an unprecedented fluxes with large statistics (in...
We report on the first 180 days of Rossi X-Ray Timing Explorer observations outburst black hole candidate IGR J17091–3624. This source exhibits a broad variety complex light curve patterns including periods strong flares alternating with quiet intervals. Similar in X-ray curves have been seen (up to now) unique system GRS 1915+105. In context variability classes defined by Belloni et al. for 1915+105, we find that J17091–3624 shows ν, ρ, α, λ, β, and μ as well which resemble χ class, all...
We report on a complete set of early optical afterglows gamma-ray bursts (GRBs) obtained with the Robotic Optical Transient Search Experiment (ROTSE-III) telescope network from 2005 March through 2007 June. This is comprised 12 and Swift/X-Ray Telescope observations, median ROTSE-III response time 45 s after start γ-ray emission (8 GCN notice time). These span 4 orders magnitude in luminosity, contemporaneous X-ray detections allow multi-wavelength spectral analysis. Excluding flares,...
We report on 18 months of multiwavelength observations the blazar 3C 454.3 (Crazy Diamond) carried out in July 2007-January 2009. show results AGILE campaigns which took place May-June 2008, July-August and October 2008-January During May 2009 period, source average flux was highly variable, from an gamma-ray F(E>100MeV) > 200E-8 ph/cm2/s to F(E>100MeV)~80E-8 The spectrum between 100 MeV 1 GeV can be fit by a simple power law (Gamma_GRID ~ 2.0 2.2). Only 3-sigma upper limits derived 20-60...