A5114374183- Pulsars and Gravitational Waves Research
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- Astrophysics and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Radio Astronomy Observations and Technology
- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Superconducting Materials and Applications
- Astronomy and Astrophysical Research
- High-pressure geophysics and materials
- Particle Accelerators and Free-Electron Lasers
- Astronomical Observations and Instrumentation
- History and Developments in Astronomy
- GNSS positioning and interference
- Particle accelerators and beam dynamics
- Geophysics and Sensor Technology
- Inertial Sensor and Navigation
- Advanced Frequency and Time Standards
- Nuclear Physics and Applications
- Cosmology and Gravitation Theories
- Planetary Science and Exploration
- Spacecraft and Cryogenic Technologies
- Particle Detector Development and Performance
- Computational Physics and Python Applications
Willamette University
2011-2014
University of California, Santa Cruz
2003-2013
Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
2008
United States Naval Research Laboratory
1996-2008
Kavli Institute for Particle Astrophysics and Cosmology
2008
Stanford University
2008
SLAC National Accelerator Laboratory
2008
University of British Columbia
2003
Pennsylvania State University
2003
University of California, Los Angeles
2003
The Nuclear Spectroscopic Telescope Array (NuSTAR) mission, launched on 2012 June 13, is the first focusing high-energy X-ray telescope in orbit. NuSTAR operates band from 3 to 79 keV, extending sensitivity of far beyond ∼10 keV cutoff achieved by all previous satellites. inherently low background associated with concentrating light enables probe hard sky a more than 100-fold improvement over collimated or coded mask instruments that have operated this bandpass. Using its unprecedented...
There are now about 50 known radio pulsars in binary systems, including at least five double neutron star binaries. In some cases, the stellar masses can be directly determined from measurements of relativistic orbital effects. others, only an indirect or statistical estimate is possible. We review general problem mass measurement pulsar binaries and critically discuss all current estimates their companions. find that significant constraints exist on 21 companions pulsars. All consistent...
In recent years, the number of pulsars with secure mass measurements has increased to a level that allows us probe underlying neutron star (NS) distribution in detail. We critically review radio pulsar measurements. For first time, we are able analyze sizable population NSs flexible modeling approach can effectively accommodate skewed and asymmetric measurement errors. find have evolved through different evolutionary paths reflect distinctive signatures dissimilar peak cutoff values. double...
The pulsar B1620-26 has two companions, one of stellar mass and planetary mass. We detected the companion with use Hubble Space Telescope observations. color magnitude indicate that it is an undermassive white dwarf (0.34 +/- 0.04 solar mass) age 480 x 10(6) 140 years. This places a constraint on recent history this triple system supports scenario in which current configuration arose through dynamical exchange interaction cluster core. implies planets may be relatively common low-metallicity...
view Abstract Citations (211) References (22) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Timing Behavior of 96 Radio Pulsars Arzoumanian, Z. ; Nice, D. J. Taylor, H. Thorsett, S. E. We present results from observations 104 pulsars made between 1989 August and 1993 April, including timing solutions for them. Pulse profiles were recorded at four frequencies in the range 0.4-1.64 GHz, yielding topocentric pulse arrival times with uncertainties order 10-3...
Astrometry can bring powerful constraints to bear on a variety of scientific questions about neutron stars, including their origins, astrophysics, evolution, and environments. Using phase-referenced observations at the VLBA, in conjunction with pulsar gating in-beam calibration, we have measured parallaxes proper motions for 14 pulsars. The smallest parallax our sample is 0.13+-0.02 mas PSR B1541+09, which has most probable distance 7.2+1.3-1.1 kpc. We detail methods, initial VLA surveys...
We present updated analyses of pulse profiles and their arrival times from PSR B1534+12, a 37.9 ms radio pulsar in orbit with another neutron star. A high-precision timing model is derived 22 yr data accounts for all astrophysical processes that systematically affect times. Five "post-Keplerian" parameters are measured represent relativistic corrections to the standard Keplerian quantities pulsar's binary orbit. These then used test general relativity by comparing measurements predicted...
We report on HST and Palomar optical images of the field GRB 990123, obtained 8 9 February 1999. find that transient (OT) associated with 990123 is located an irregular galaxy, magnitude V=24.20 +/- 0.15. The strong metal absorption lines seen in spectrum OT, along low probability a chance superposition, lead us to conclude this galaxy host GRB. OT projected within ~1'' visible stellar host, nearer edge than center. cannot, basis, rule out galactic nucleus as site GRB, since unusual...
We have observed 1.7 × 106 individual pulses from the millisecond pulsar PSR B1937+21. About one pulse in 10,000 has more than 20 times mean "pulse-on" flux density, and as large 300 average were observed. Comparable behavior previously been only for Crab pulsar. Giant B1937+21 are seen both main interpulse components, their amplitude distribution roughly a power-law shape. Strong differ greatly emission: they narrower, systematically delayed by some 40-50 μs, many nearly 100% circularly...
We determined the distances to nine pulsars by parallax measurements using NRAO Very Long Baseline Array, doubling number of with accurate distance measurements. Broadband phase modeling was used calibrate varying dispersive effects ionosphere and remove resulting errors from phase-referenced VLBI data. The parallaxes have a typical accuracy 100 μas or better, yielding as 2%. also report new proper motion these pulsars, 400 yr-1 better.
The highest velocity neutron stars establish stringent constraints on natal kicks, asymmetries in supernova core collapse, and the evolution of close binary systems. Here we present first results a long-term pulsar astrometry program using VLBA. We measure proper motion parallax for B1508+55, leading to model-independent estimates its distance (2.37 kpc) transverse (1083 km s-1), directly measured star. trace back from Galactic latitude 523 birth site plane near Cyg OB associations, find...
view Abstract Citations (123) References (30) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS PSR B1620-26: A Binary Radio Pulsar with a Planetary Companion? Thorsett, S. E. ; Arzoumanian, Z. Taylor, J. H. B1620-26, in the globular cluster M4, is millisecond pulsar an approximately 0.3 solar mass companion 0.7 AU orbit. It was recently realized (Backer, 1993) that timing observations of this show, addition to linear spin-down, large-period second derivative...
We have continued our long-term study of the double neutron star binary pulsar PSR B1534+12, using new instrumentation to make very high precision measurements at Arecibo Observatory. significantly improved solution for astrometric, spin, and orbital parameters system as well five "post-Keplerian" that can be used test gravitation theory. The results are in good agreement with predictions general relativity. With assumption relativity is correct theory gravity classical regime, allow us...
view Abstract Citations (159) References (23) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Magnetic Fields, Ages, and Original Spin Periods of Millisecond Pulsars Camilo, F. ; Thorsett, S. E. Kulkarni, R. Accurate determination the spin-down rates millisecond pulsars requires consideration apparent acceleration due to their high transverse velocities. We show that for several nearby neglect this effect leads substantial errors in inferred pulsar ages...
The millisecond pulsar PSR B1620-26, in the globular cluster M4, has a white dwarf companion half-year orbit. Anomalously large variations pulsar's apparent spin-down rate have suggested presence of second much wider Using timing observations made on more than 700 days spanning 11 yr, we confirm this anomalous behavior. We explicitly demonstrate, for first time, that model consisting sum two noninteracting Keplerian orbits can account observed signal. Both circular and elliptical are...
The Chandrasekhar mass limit sets the scale for late evolutionary stages of massive stars, including formation neutron stars in core collapse supernovae. Because its value depends on gravitational constant $G$, masses these retain a record past values $G$. Using Bayesian statistical techniques, I show that measurements young and old pulsar binaries $\stackrel{\ifmmode \dot{}\else...
view Abstract Citations (141) References (21) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Eclipsing Millisecond Pulsar PSR 1957+20 Fruchter, A. S. ; Berman, G. Bower, Convery, M. Goss, W. Hankins, T. H. Klein, J. R. Nice, D. Ryba, F. Stinebring, Taylor, Thorsett, E. Weisberg, Information obtained over the past year on eclipsing millisecond pulsar 1957 + 20 and its orbiting companion is discussed. found to be similar in many ways other pulsars: spin...
In relativistic gravity, a spinning pulsar will precess as it orbits compact companion star. We have measured the effect of such precession on average shape and polarization radiation from PSR B1534+12. also detected, with limited precision, special-relativistic aberration revolving beam due to orbital motion. Our observations fix system geometry, including misalignment between spin angular momenta, yield measurement time scale consistent predictions general relativity.
We describe a comprehensive pulsar monitoring campaign for the Large Area Telescope (LAT) on {\em Fermi Gamma-ray Space Telescope} (formerly GLAST). The detection and study of pulsars in gamma rays give insights into populations neutron stars supernova rates Galaxy, particle acceleration mechanisms star magnetospheres, "engines" driving wind nebulae. LAT's unprecedented sensitivity between 20 MeV 300 GeV together with its 2.4 sr field-of-view makes many gamma-ray likely, justifying over two...
We report the detection of pulsed gamma-ray emission from fast millisecond pulsars (MSPs) B1937+21 (also known as J1939+2134) and B1957+20 (J1959+2048) using 18 months survey data recorded by Fermi Large Area Telescope timing solutions based on radio observations conducted at Westerbork Nançay telescopes. In addition, we analyzed archival Rossi X-ray Timing Explorer XMM-Newton for two MSPs, confirming properties PSR finding evidence (∼4σ) first time. both cases profile is characterized peaks...
Abstract We present a 34 yr timing solution of the redback pulsar system Terzan 5A (Ter5A). Ter5A, also known as B1744−24A or J1748−2446A, has 11.56 ms pulse period, ~0.1 M ⊙ dwarf companion star, and an orbital period 1.82 hr. Ter5A displays highly variable eclipses perturbations. Using new techniques, we have determined phase-connected for this over yr. This is longest ever published pulsar. find that pulsar’s spin variability much larger than most globular cluster pulsars. In fact, nine...
We present a large sample of high-precision, coherently-dedispersed polarization profiles millisecond pulsars (MSPs) at frequencies between 410 and 1414 MHz. These data include the first polarimetric observations several pulsars, low-frequency for others. Our support previous suggestions that pulse shapes polarimetry MSPs are more complex than those their slower relatives. An immediate conclusion is polarimetry-based classification schemes proposed young only limited use when applied to pulsars.
We have made timing observations of binary pulsar PSR B1534+12 with radio telescopes at Arecibo, Green Bank, and Jodrell Bank. By combining our new data collected up to seven years earlier, we obtain a significantly improved solution for the astrometric, spin, orbital parameters system. For first time in any system, no fewer than five relativistic or "post-Keplerian" are measurable useful accuracies theory-independent way. find period system be decreasing rate close that expected from...