A5033708290- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Stellar, planetary, and galactic studies
- Astronomical Observations and Instrumentation
- Pulsars and Gravitational Waves Research
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- High-pressure geophysics and materials
- Astrophysics and Cosmic Phenomena
- Astro and Planetary Science
- Galaxies: Formation, Evolution, Phenomena
- Mechanics and Biomechanics Studies
- Atmospheric and Environmental Gas Dynamics
- Adaptive optics and wavefront sensing
- Geophysics and Gravity Measurements
- SAS software applications and methods
- Solar and Space Plasma Dynamics
- History and Developments in Astronomy
- Scientific Measurement and Uncertainty Evaluation
- Superconducting Materials and Applications
- Calibration and Measurement Techniques
- Particle Accelerators and Free-Electron Lasers
- Radio Astronomy Observations and Technology
- Spectroscopy and Laser Applications
- Optical Systems and Laser Technology
University of Warwick
2016-2025
ARC Centre of Excellence for Gravitational Wave Discovery
2017-2023
Monash University
2016-2023
Center for Astrophysics Harvard & Smithsonian
2007-2021
Michigan State University
2016
SRON Netherlands Institute for Space Research
2016
Radboud University Nijmegen
2007-2016
Texas Tech University
2016
Louisiana State University
2016
University of Michigan
2016
Abstract We report the discovery and monitoring of near-infrared counterpart (AT2017gfo) a binary neutron-star merger event detected as gravitational wave source by Advanced Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo (GW170817) short gamma-ray burst Fermi Gamma-ray Burst Monitor (GBM) Integral SPI-ACS (GRB 170817A). The evolution transient light is consistent with predictions for behavior “kilonova/macronova” powered radioactive decay massive neutron-rich nuclides...
The INT Photometric Halpha Survey of the Northern Galactic Plane (IPHAS) is a 1800 square degrees CCD survey northern Milky Way spanning latitude range -5 < b +5 (degrees) and reaching down to r' ~ 20 (10-sigma). It may increase number known emission line sources by an order magnitude. Representative observations assessment point-source data from IPHAS, now underway, are presented. obtained Wide Field Camera images in narrow-band, Sloan i' broad-band, filters. We simulate IPHAS (r' -...
The VST Photometric Halpha Survey of the Southern Galactic Plane and Bulge (VPHAS+) is surveying southern Milky Way in u, g, r, i at 1 arcsec angular resolution. Its footprint spans latitude range -5 < b +5 all longitudes south celestial equator. Extensions around Centre to latitudes +/-10 bring much Bulge. This ESO public survey, begun on 28th December 2011, reaches down 20th magnitude (10-sigma) will provide single-epoch digital optical photometry for 300 million stars. observing strategy...
Ultracompact binaries with orbital periods less than a few hours will dominate the gravitational wave signal in mHz regime. Until recently, 10 systems were expected have predicted strong enough to be detectable by Laser Interferometer Space Antenna (LISA), so-called `verification binaries'. System parameters, including distances, are needed provide an accurate prediction of strength measured LISA. Using parallaxes from {\sl Gaia} Data Release 2 we calculate signal-to-noise ratios (SNR) for...
We present observations of the optical afterglow GRB\,170817A, made by {\it Hubble Space Telescope}, between February and August 2018, up to one year after neutron star merger, GW170817. The shows a rapid decline beyond $170$~days, confirms jet origin for observed outflow, in contrast more slowly declining expectations `failed-jet' scenarios. show here that broadband (radio, optical, X-ray) is consistent with structured outflow where an ultra-relativistic jet, Lorentz factor...
The mergers of binary compact objects such as neutron stars and black holes are central interest to several areas astrophysics, including the progenitors gamma-ray bursts (GRBs), sources high-frequency gravitational waves likely production sites for heavy element nucleosynthesis via rapid capture (the r-process). These elements include some great geophysical, biological cultural importance, thorium, iodine gold. Here we present observations exceptionally bright burst GRB 230307A. We show...
Abstract Galactic compact binaries with orbital periods shorter than a few hours emit detectable gravitational waves (GWs) at low frequencies. Their GW signals can be detected the future Laser Interferometer Space Antenna (LISA). Crucially, they may useful in early months of mission operation helping to validate LISA's performance comparison prelaunch expectations. We present an updated list 55 candidate LISA-detectable measured properties, for which we derive distances based on Gaia Data...
Three periodically variable stars have recently been discovered (V407 Vul, P= 9.5 min; ES Cet, 10.3 RX J0806.3+1527, 5.3 min) with properties that suggest their photometric periods are also orbital periods, making them the most compact binary known. If true, this might indicate close, detached, double white dwarfs able to survive onset of mass transfer caused by gravitational wave radiation and emerge as semi‐detached, hydrogen‐deficient known AM CVn stars. The accreting in such systems...
We present the first results of coordinated multiwavelength observations Galactic black hole GX 339-4 in a canonical low/hard state, obtained during its 2004 outburst. XMM-Newton observed source for two revolutions, or approximately 280 ks; RXTE monitored throughout this long stare. The resulting data offer best view yet inner accretion flow geometry which is thought to be analogous low-luminosity active galactic nuclei. spectra clearly reveal presence cool disk component and relativistic Fe...
We present outburst spectroscopy of GX339-4 which may reveal the motion its elusive companion star. NIII lines exhibit sharp emission components moving over ~300 km/s in a single night. The most plausible interpretation these is that they are formed by irradiation star and velocities indicate orbital motion. also detect wings HeII 4686A line changes morphology. No previously proposed period consistent with periodic behavior all measures. However, sensible solutions obtained for periods...
The INT/WFC Photometric H-Alpha Survey of the Northern Galactic Plane (IPHAS) is a 1800 square degrees imaging survey covering latitudes |b| < 5 deg and longitudes l = 30 to 215 in r, i H-alpha filters using Wide Field Camera (WFC) on 2.5-metre Isaac Newton Telescope (INT) La Palma. We present first quality-controlled globally-calibrated source catalogue derived from survey, providing single-epoch photometry for 219 million unique sources across 92% footprint. observations were carried out...
Abstract We present Hubble Space Telescope ( HST ) and Chandra imaging, combined with Very Large MUSE integral field spectroscopy of the counterpart host galaxy first binary neutron star merger detected via gravitational-wave emission by LIGO Virgo, GW170817. The galaxy, NGC 4993, is an S0 at z = 0.009783. There evidence for large, face-on spiral shells in continuum edge-on features visible nebular lines. This suggests that 4993 has undergone a relatively recent <mml:math...
We present a dynamical model of the high mass X-ray binary LMC X-1 based on high-resolution optical spectroscopy and extensive near-infrared photometry. From our new data we find an orbital period P = 3.90917 ± 0.00005 days. refined analysis All Sky Monitor from RXTE 3.9094 0.0008 days, which is consistent with period. A simple Thomson scattering in stellar wind can account for modulation seen light curves. The V − K color star (1.17 0.05) implies AV 2.28 0.06, much larger than previously...
Using the Very Long Baseline Array, we have measured a trigonometric parallax for micro quasar GRS 1915+105, which contains black hole and K-giant companion. This yields direct distance estimate of 8.6 (+2.0,-1.6) kpc revised mass 12.4 (+2.0,-1.8) Msun. 1915+105 is at about same as some HII regions water masers associated with high-mass star formation in Sagittarius spiral arm Galaxy. The absolute proper motion -3.19 +/- 0.03 mas/y -6.24 0.05 toward east north, respectively, corresponds to...
We present a method which uses colour-colour cuts on SDSS photometry to select white dwarfs with hydrogen rich (DA) atmospheres without the recourse spectroscopy. This results in sample of DA that is 95% complete at an efficiency returning true dwarf 62%. The approach was applied Data Release 7 for objects and lead 4636 spectroscopically confirmed g<=19; ~70% increase compared Eisenstein et al.'s 2006 sample. Including photometric-only objects, we estimate factor 3 dwarfs. find spectroscopic...
ABSTRACT We report the results of optical follow-up observations 29 gravitational-wave (GW) triggers during first half LIGO–Virgo Collaboration (LVC) O3 run with Gravitational-wave Optical Transient Observer (GOTO) in its prototype 4-telescope configuration (GOTO-4). While no viable electromagnetic (EM) counterpart candidate was identified, we estimate our 3D (volumetric) coverage using test light curves on- and off-axis gamma-ray bursts kilonovae. In cases where source region observable...
ABSTRACT The Gravitational-wave Optical Transient Observer (GOTO) is an array of wide-field optical telescopes, designed to exploit new discoveries from the next generation gravitational wave detectors (LIGO, Virgo, and KAGRA), study rapidly evolving transients, multimessenger opportunities arising neutrino very high energy gamma-ray triggers. In addition a rapid response mode, will also perform sensitive, all-sky transient survey with few day cadence. facility features novel, modular design...
We observed the bright phase of 2003 outburst Galactic black hole candidate H1743-322 in X-rays simultaneously with Chandra and RXTE on four occasions. The HETGS spectra reveal narrow, variable (He-like) Fe XXV (H-like) XXVI resonance absorption lines. In first observation, line has a FWHM 1800 ± 400 km s-1 blueshift 700 200 s-1, suggesting that highly ionized medium is an outflow. Moreover, to vary significantly timescale few hundred seconds which corresponds Keplerian orbital period at...
The distance to the black hole binary GX339-4 remains a topic of debate. We examine high-resolution optical spectra NaD lines resolving velocity structure along line sight. find this be complex, with at least nine components, mostly blue-shifted, spanning range nearly 200km/s. presence components large blue-shift rules out nearby location and requires that located or beyond tangent point, implying lower limit ~6kpc. significant red-shifted component +30km/s is even more intriguing as also...
We present a variability study of the black hole candidate and X-ray transient H1743-322 during its 2003-2004 outburst. analyzed five Rossi X-Ray Timing Explorer observations that were performed as part multiwavelength campaign, well six from early rise The source was observed in several states showed various types variability, including high-frequency quasi-periodic oscillations (QPOs) at 240 160 Hz (i.e., with 3 : 2 frequency ratio), low-frequency QPOs, strong variations on timescale few...
The bright X-ray transient H1743−322 was observed daily by the Rossi Timing Explorer during most of its eight-month outburst in 2003. We present a detailed spectral analysis and supporting timing all these data, we discuss behavior evolution source terms three principal states defined Remillard McClintock. These results are complemented Very Large Array data obtained at six frequencies that provide quite complete coverage entire cycle 4.860 GHz 8.460 GHz. also photometric finding charts for...