Goddard Space Flight Center contributions to the University of California, Santa Cruz Summer Workshop on High Energy Transients

Topics addressing the characteristics and emission mechanisms of gamma ray bursts and neutron and gamma ray emission from solar flares are discussed. In addition, observational aspects of gamma ray astronomy are addressed with particular attention given to optical transients associated with gamma ray bursts

A Millisecond Interferometric Search for Fast Radio Bursts with the Very Large Array

We report on the first millisecond timescale radio interferometric search for the new class of transient known as fast radio bursts (FRBs). We used the Very Large Array (VLA) for a 166-hour, millisecond imaging campaign to detect and precisely localize an FRB. We observed at 1.4 GHz and produced visibilities with 5 ms time resolution over 256 MHz of bandwidth. Dedispersed images were searched for transients with dispersion measures from 0 to 3000 pc/cm3. No transients were detected in observations of high Galactic latitude fields taken from September 2013 though October 2014. Observations of a known pulsar show that images typically had a thermal-noise limited sensitivity of 120 mJy/beam (8 sigma; Stokes I) in 5 ms and could detect and localize transients over a wide field of view. Our nondetection limits the FRB rate to less than 7e4/sky/day (95% confidence) above a fluence limit of 1.2 Jy-ms. Assuming a Euclidean flux distribution, the VLA rate limit is inconsistent with the published rate of Thornton et al. We recalculate previously published rates with a homogeneous consideration of the effects of primary beam attenuation, dispersion, pulse width, and sky brightness. This revises the FRB rate downward and shows that the VLA observations had a roughly 60% chance of detecting a typical FRB and that a 95% confidence constraint would require roughly 500 hours of similar VLA observing. Our survey also limits the repetition rate of an FRB to 2 times less than any known repeating millisecond radio transient.Comment: Submitted to ApJ. 13 pages, 9 figure

Aerospace medicine and biology: A continuing bibliography with indexes, supplement 130, July 1974

This special bibliography lists 291 reports, articles, and other documents introduced into the NASA scientific and technical information system in June 1974

Quantifying the impact of data quality on searches for gravitational waves from binary coalescing systems with LIGO

Gravitational waves are ripples in space-time itself, predicted by Einstein\u27s General theory of relativity, which propagate at the speed of light and are not scattered or extinguished by passing through matter almost at all. In particular, the gravitational waves from the coalescences of binary systems of compact objects, such as neutron stars and black holes, are exciting prospects for observation. The Laser Interferometer Gravitational-wave Observatory experiment intends to make the _x000C_first direct measurement of gravitational waves, and use the results to uncover new astrophysics. These observations will not be limited by extinction from dust and gas, and will probe astrophysical systems at distances of tens of millions to hundreds of millions of parsecs. The LIGO Scienti_x000C_c Collaboration searches for gravitational waves from a variety of astrophysical sources amongst this data. These searches are complicated by the presence of transients of non-astrophysical origin in the interferometer data. Control system and equipment malfunctions, as well as coupling from ground motions and electromagnetic fields, are the most common noises that detract from the LIGO data quality. These sources of noise increase the false alarm rate for gravitational wave searches, and need to be vetoed to search the data effectively for detections, or to set upper limits properly. Vetoes for the searches are created from the available data quality information, and their e_x000B_ect on the overall sensitivity of LIGO to these sources must be analyzed. During the S5 science run, I evaluated the data quality information for use as vetoes for the LIGO search for compact binary coalescences. The use of these vetoes made this search more sensitive to distant gravitational radiation sources by decreasing the non-astrophysical background from noise transients. In this dissertation, I quantify the impact of data quality on searches for gravitational waves with LIGO, and the resulting increased sensitivity to binary coalescing systems