A5023515416- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Pulsars and Gravitational Waves Research
- Radio Astronomy Observations and Technology
- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- High-pressure geophysics and materials
- Astrophysical Phenomena and Observations
- Particle Detector Development and Performance
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Geophysics and Gravity Measurements
- Astronomical Observations and Instrumentation
- Particle Accelerators and Free-Electron Lasers
- Inertial Sensor and Navigation
- Non-Destructive Testing Techniques
George Washington University
2017-2024
University of New Mexico
2024
University of Memphis
2016
Abstract We present the discovery of radio afterglow short gamma-ray burst (GRB) 210726A, localized to a galaxy at photometric redshift z ∼ 2.4. While observations commenced ≲1 day after burst, no emission was detected until ∼11 days. The subsequently brightened by factor ∼3 in span week, followed rapid decay (a “radio flare”). find that forward shock model cannot self-consistently describe multiwavelength X-ray and data, underpredicts flux flare ≈5. addition substantial energy injection,...
ABSTRACT Transient surveys are a vital tool in exploring the dynamic Universe, with radio transients acting as beacons for explosive and highly energetic astrophysical phenomena. However, performing commensal transient using imaging can require significant amount of computing power, data storage, time. With instrumentation available to us, new exciting interferometers development, it is essential that we develop efficient methods probe sky. In this paper, present results from short-duration...
ABSTRACT Short gamma-ray bursts (GRBs) are explosive transients caused by binary mergers of compact objects containing at least one neutron star. Multiwavelength afterglow observations provide constraints on the physical parameters jet, its surrounding medium, and microphysics enhanced magnetic fields accelerated electrons in blast wave front jet. The synchrotron radio emission can be tracked for much longer than other spectral regimes, it pin down evolution peak. We present results a...
Abstract We present the radio afterglow of short gamma-ray burst (GRB) 230217A, which was detected less than 1 day after prompt emission with Australia Telescope Compact Array (ATCA) and Karl G. Jansky Very Large Array. The ATCA rapid-response system automatically triggered an observation GRB 230217A following its detection by Neil Gehrels Swift Observatory began observing event just 32 minutes postburst at 5.5 9 GHz for 7 hr. Dividing hr into three time-binned images allowed us to obtain...
We discuss the observational properties of pulsar wind nebulae (PWNe) linking them to injected (at termination shock) electron spectral energy distribution and parameters magnetospheres. In particular, we (1) present spatially-resolved Chandra ACIS maps twelve PWNe measure slopes uncooled PWN spectra just downstream shock obtained from these maps, (2) consider connections between morphologies predictions magnetospheric emission models (3) limits on maximum energies particles in X-ray γ-ray...
ABSTRACT We have expanded upon earlier work that investigates the relative importance of coronal loops with isothermal versus multithermal cross-field temperature distributions. These results are important for determining if substructure in form unresolved magnetic strands. increased number targeted analysis from 19 to 207 addition 188 new multiple regions. selected all loop segments visible 171 Å images Atmospheric Imaging Assembly (AIA) had a clean background. Eighty-six were rejected...
ABSTRACT Many transient and variable sources detected at multiple wavelengths are also observed to vary radio frequencies. However, these samples typically biased towards that initially in wide-field optical, X-ray, or gamma-ray surveys. insufficiently bright higher frequencies therefore missed, leading potential gaps our knowledge of missing populations not detectable X-rays, gamma-rays. Taking advantage new state-of-the-art facilities provide high-quality images with fast survey speeds, we...
ABSTRACT A new generation of radio telescopes with excellent sensitivity, instantaneous uv coverage, and large fields view, are providing unprecedented opportunities for performing commensal transient searches. Here, we present such a search in deep observations short gamma-ray burst carried out the MeerKAT telescope South Africa at 1.3 GHz. These four hour eight different span survey lengths weeks to months. We also carry searches time slices full observations, time-scales 15 min 8 s. find...
We present the radio afterglow of short gamma-ray burst (GRB) 230217A, which was detected less than 1 day after prompt emission with Australia Telescope Compact Array (ATCA) and Karl G. Jansky Very Large (VLA). The ATCA rapid-response system automatically triggered an observation GRB 230217A following its detection by Neil Gehrels Swift Observatory began observing event just 32 minutes post-burst at 5.5 9 GHz for 7 hours. Dividing 7-hour into three time-binned images allowed us to obtain...
Short gamma-ray bursts (GRBs) are explosive transients caused by binary mergers of compact objects containing at least one neutron star. Multi-wavelength afterglow observations provide constraints on the physical parameters jet, its surrounding medium, and microphysics enhanced magnetic fields accelerated electrons in blast wave front jet. The synchrotron radio emission can be tracked for much longer than other spectral regimes, it pin down evolution peak. We present results a systematic...
The sensitivity and field of view the MeerKAT radio telescope provides excellent opportunities for commensal transient searches. We carry out a search in supernova short gamma-ray burst fields using methodologies established Chastain et al. (2023). transients L-band images with 30 minute integration times, finding 13 variable sources. compare these sources to VLASS RACS survey data, examine possible explanation variability. find that 12 are consistent variability due interstellar...
In this study we have compared coronal loops in the Extreme ultraviolet Imaging Telescope (EIT) on-board Solar and Heliospheric Observatory (SOHO) with from Transition Region Coronal Explorer (TRACE). The purpose of which is to quantitatively qualitatively examine effects spatial resolution on width implications for how a loop defined. Out twenty-two sections analyzed, find that none them were resolved EIT close TRACE loops. These findings suggest are unresolved EIT. We also examples can be...
We present the discovery of radio afterglow short $\gamma$-ray burst (GRB) 210726A, localized to a galaxy at photometric redshift $z\sim 2.4$. While observations commenced $\lesssim 1~$day after burst, no emission was detected until $\sim11~$days. The subsequently brightened by factor $\sim 3$ in span week, followed rapid decay (a "radio flare"). find that forward shock model cannot self-consistently describe multi-wavelength X-ray and data, underpredicts flux flare $\approx 5$. addition...
Magnetar giant flares (MGFs) are enormous eruptions likely triggered by surface disruptions in magnetars, neutron stars with the strongest-known magnetic fields. Such events can be detected both X- and gamma-ray bands, but very rare. Almost 30 magnetars have been cataloged our Galaxy, exhibiting occasional X-ray activity, only two produced to date. The most recent one, emitted SGR 1806-20 2004, showed an initial short bright main spike, causing saturation of observing instruments thus...