M. S. Roberts
A5103075542- Pulsars and Gravitational Waves Research
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Astronomical Observations and Instrumentation
- Stellar, planetary, and galactic studies
- Radio Astronomy Observations and Technology
- Geophysics and Gravity Measurements
- Dark Matter and Cosmic Phenomena
- Particle Detector Development and Performance
- Galaxies: Formation, Evolution, Phenomena
- Particle Accelerators and Free-Electron Lasers
- Astrophysics and Star Formation Studies
- Photocathodes and Microchannel Plates
- High-pressure geophysics and materials
- Atmospheric Ozone and Climate
- History and Developments in Astronomy
- Neutrino Physics Research
- Superconducting Materials and Applications
- Adaptive optics and wavefront sensing
- Solar and Space Plasma Dynamics
- Particle physics theoretical and experimental studies
- Spectroscopy and Laser Applications
- Nuclear Physics and Applications
University of Wollongong
2024
Eureka Scientific
2014-2024
University of Mississippi
2023
New York University
2014-2019
New York University Abu Dhabi
2014-2019
Professional Examination Service
2016
Pennsylvania State University
2006-2015
Ithaca College
2012-2015
Stanford University
1997-2013
National Radio Astronomy Observatory
1975-2011
The view that emotional intelligence should be included within the traditional cognitive abilities framework was explored in 3 studies (total N = 530) by investigating relations among measures of intelligence, human abilities, and personality. suggest status construct is limited measurement properties its tests. Measures based on consensual scoring exhibited low reliability. Self-report had salient loadings well-established personality factors, indicating a lack divergent validity. These...
The High Resolution Fly's Eye (HiRes) experiment has observed the Greisen-Zatsepin-Kuzmin suppression (called GZK cutoff) with a statistical significance of five standard deviations. HiRes' measurement flux ultrahigh energy (UHE) cosmic rays shows sharp at an $6 \times 10^{19}$ eV, consistent expected cutoff energy. We observe ``ankle'' cosmic-ray spectrum as well, $4 10^{18}$ eV. describe experiment, data collection, analysis, and estimate systematic uncertainties. results are presented...
Radio pulsars with millisecond spin periods are thought to have been spun up by transfer of matter and angular momentum from a low-mass companion star during an X-ray-emitting phase. The the neutron stars in several such X-ray binary (LMXB) systems shown be regime, but no radio pulsations detected. Here we report on detection follow-up observations nearby pulsar (MSP) circular orbit optically identified star. Optical indicate that accretion disk was present this system within last decade....
We report studies of ultra-high energy cosmic ray composition via analysis depth airshower maximum (Xmax), for events collected by the High Resolution Fly's Eye (HiRes) observatory. The HiRes data are consistent with a constant elongation rate d<Xmax>/d(log(E)) 47.9 +- 6.0 (stat.) 3.2 (syst.)g/cm^2/decade energies between 1.6 EeV and 63 EeV, predominantly protonic rays when interpreted QGSJET01 QGSJET-II high-energy hadronic interaction models. These measurements constrain models in which...
We describe an ongoing search for pulsars and dispersed pulses of radio emission, such as those from rotating transients (RRATs) fast bursts, at 350 MHz using the Green Bank Telescope. With Ultimate Pulsar Processing Instrument, we record 100 bandwidth divided into 4096 channels every 81.92 μs. This survey will cover entire sky visible to Telescope (δ > −40°, or 82% sky) outside Galactic Plane be sensitive enough detect slow low dispersion measure (<30 pc cm−3) millisecond (MSPs) with a 0.08...
We have measured the cosmic ray spectrum above 10(17.2) eV using two air-fluorescence detectors of High Resolution Fly's Eye observatory operating in monocular mode. describe detector, phototube, and atmospheric calibrations, as well analysis techniques for detectors. fit to a model consisting galactic extragalactic sources.
We report a major outburst from the anomalous X-ray pulsar 1E 2259+586, in which over 80 bursts were detected 4 hr using Rossi X-Ray Timing Explorer. The range duration 2 ms to 3 s and have fluences 2-10 keV band that × 10-11 5 10-9 ergs cm-2. simultaneously observed increases of pulsed persistent emission by an order magnitude relative quiescent levels. Both decayed significantly during course our 14 ks observation. Correlated spectral hardening was also observed, with spectrum softening In...
This paper reports the first discovery of TeV gamma-ray emission from a supernova remnant made with CANGAROO 3.8 m Telescope. gamma rays were detected at sky position and extension coincident north-east (NE) rim shell-type Supernova (SNR) SN1006 (Type Ia). has been most likely candidate for an extended Gamma-ray source, since clear synchrotron X-ray rims was recently observed by ASCA (Koyama et al. 1995), which is strong evidence existence very high energy electrons up to hundreds in SNR....
We present precise phase-connected pulse timing solutions for 16 gamma-ray-selected pulsars recently discovered using the Large Area Telescope (LAT) on Fermi Gamma-ray Space plus one very faint radio pulsar (PSR J1124-5916) that is more effectively timed with LAT. describe analysis techniques including a maximum likelihood method determining times of arrival from unbinned photon data. A major result this work improved position determinations, which are crucial multi-wavelength follow up. For...
We report the discovery of a new X-ray pulsar, XTE J1810-197, that was serendipitously discovered on 2003 July 15 by Rossi X- Ray Timing Explorer (RXTE) while observing soft gamma repeater SGR 1806-20. The pulsar has 5.54 s spin period, spectrum (with photon index ≈4), and is detectable in earlier RXTE observations back to January but not before. These show transient outburst began between 2002 November 17 23 source's persistent flux been declining since then. exhibits high spin-down rate ≈...
The composition of Ultra High Energy Cosmic Rays (UHECR) is measured with the Resolution Fly's Eye cosmic ray observatory (HiRes) data using Xmax technique. Data were collected in stereo between 1999 November and 2001 September. are reconstructed well-determined geometry. Measurements atmospheric transmission incorporated reconstruction. detector resolution found to be 30 g cm^-2 13% Energy. elongation rate 10^18.0 eV 10^19.4 54.5 +/- 6.5 (stat) 4.5 (sys) per decade. This compared...
view Abstract Citations (218) References (18) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The rotation curve and geometry of M31 at large galactocentric distances. Roberts, M. S. ; Whitehurst, R. N. New 21-cm observations the southern end M3l indicate (1) that plane H I is bent away from conventional by up to 5 kpc (2) rotational velocity essentially constant over outer 10 kpc, i.e., 20 30 radius. latter implies a mass increases linearly with R this range...
We searched for radio pulsars in 25 of the non-variable, unassociated sources Fermi LAT Bright Source List with Green Bank Telescope at 820 MHz. report discovery three and gamma-ray millisecond (MSPs) from a high Galactic latitude subset these sources. All are binary systems, which would have made them virtually impossible to detect blind pulsation searches. They seem be relatively normal, nearby (<=2 kpc) pulsars. These observations, combination detection gamma-rays other known MSPs, imply...
In the last few years, over 43 millisecond radio pulsars have been discovered by targeted searches of unidentified gamma-ray sources found Fermi Gamma-Ray Space Telescope. A large fraction these are in compact binaries with low-mass companions. These systems often show eclipses pulsar signal and commonly known as black widows redbacks because is gradually destroying its companion. this paper, we report on optical discovery four strongly irradiated All modulations their color luminosity at...
view Abstract Citations (226) References (59) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Density wave theory and the classification of spiral galaxies. Roberts, W. W., Jr. ; M. S. Shu, F. H. Axisymmetric models disk galaxies taken together with density allow one to distinguish categorize by means two fundamental galactic parameters: total mass galaxy, divided a characteristic dimension, degree concentration toward center. These parameters govern strength...
Over the summer of 2007, we obtained 1191 hr "drift-scan" pulsar search observations with Green Bank Telescope at a radio frequency 350 MHz. Here describe survey setup, procedure, and discovery follow-up timing 13 pulsars. Among new discoveries, one (PSR J1623−0841) was discovered only through its single pulses, two (PSRs J1327−0755 J1737−0814) are millisecond pulsars, another J2222−0137) is mildly recycled pulsar. PSR 2.7 ms dispersion measure (DM) 27.9 pc cm−3 in an 8.7 day orbit minimum...
We present a summary of the Fermi Pulsar Search Consortium (PSC), an international collaboration radio astronomers and members Large Area Telescope (LAT) collaboration, whose goal is to organize follow-up observations pulsars pulsar candidates among LAT gamma-ray source population. The PSC includes observers with expertise using world's largest telescopes that together cover full sky. have performed very deep all 35 discovered in blind frequency searches data, resulting discovery pulsations...
We provide timing solutions for 45 radio pulsars discovered by the Robert C. Byrd Green Bank Telescope. These were found in North Celestial Cap pulsar survey, an all-GBT-sky survey being carried out at a frequency of 350 MHz. include data from Telescope and Low Frequency Array. Our sample includes five fully recycled millisecond (MSPs, three which are binary system), new relativistic double neutron star system, intermediate mass pulsar, mode-changing 138-ms with very low magnetic field,...
Abstract The ExoClock project is an inclusive, integrated, and interactive platform that was developed to monitor the ephemerides of Ariel targets increase mission efficiency. makes best use all available resources, i.e., observations from ground telescopes, midtime values literature, finally, space instruments. Currently, network includes 280 participants with telescopes capable observing 85% currently known candidate targets. This work results ∼1600 obtained up 2020 December 31 network....
Sixteen pulsars have been discovered so far in blind searches of photons collected with the Large Area Telescope on Fermi Gamma-ray Space Telescope. We here report discovery radio pulsations from two them. PSR J1741-2054, period P=413ms, was detected archival Parkes telescope data and subsequently has at Green Bank (GBT). Its received flux varies greatly due to interstellar scintillation it a very small dispersion measure DM=4.7pc/cc, implying distance ~0.4kpc possibly smallest luminosity...
For a homogeneous all-sky sample of faint Sc I-Sc II galaxies, we present velocities, magnitudes, and diameters. The 96 3500 <V< 6500 kml sec, are used to evaluate the coefficients describing change in apparent magnitude with path length through Galaxy, each galaxy, luminosity class, linear diameter. is also decrease diameter Galaxy atmosphere. Such corrections must be applied remove all systematic effects as function position on sky before study Hubble flow can properly undertaken....