K. L. Page
A5060680432- Gamma-ray bursts and supernovae
- SAS software applications and methods
- Astronomical Observations and Instrumentation
- Astrophysical Phenomena and Observations
- Astronomy and Astrophysical Research
- Pulsars and Gravitational Waves Research
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Galaxies: Formation, Evolution, Phenomena
- Astro and Planetary Science
- Particle Detector Development and Performance
- X-ray Spectroscopy and Fluorescence Analysis
- Astrophysics and Star Formation Studies
- Advanced X-ray Imaging Techniques
- Geophysics and Gravity Measurements
- Particle Accelerators and Free-Electron Lasers
- High-pressure geophysics and materials
- Solar and Space Plasma Dynamics
- Adaptive optics and wavefront sensing
- Mechanics and Biomechanics Studies
- History and Developments in Astronomy
- Laser-Plasma Interactions and Diagnostics
- Radio Astronomy Observations and Technology
- Statistical and numerical algorithms
- Inertial Sensor and Navigation
University of Leicester
2015-2024
University College London
2010-2024
University of Southampton
2017
Istituto di Astrofisica Spaziale e Fisica cosmica di Palermo
2005-2014
Pennsylvania State University
2005-2011
Southwest Research Institute
2011
Charles Sturt University
1991-2009
University of Nevada, Las Vegas
2005-2009
Goddard Space Flight Center
2007-2009
Brera Astronomical Observatory
2005
We present a homogeneous X-ray analysis of all 318 gamma-ray bursts detected by the telescope (XRT) on Swift satellite up to 2008 July 23; this represents largest sample GRB data published date. In Sections 2–3, we detail methods which Swift-XRT team has developed produce enhanced positions, light curves, hardness ratios and spectra presented in paper. Software using these continues create such products for new GRBs observed Swift-XRT. also web-based tools allowing users any object XRT, not...
We present new observations of the early X-ray afterglows first 27 gamma-ray bursts (GRBs) well observed by Swift X-Ray Telescope (XRT). The show a canonical behavior, where light curve broadly consists three distinct power-law segments: (1) an initial very steep decay (∝t-α with 3 ≲ α1 5), followed (2) shallow (0.5 α2 1.0), and finally (3) somewhat steeper (1 α3 1.5). These segments are separated two corresponding break times, tbreak,1 500 s 103 tbreak,2 104 s. On top this many events have...
Context.Swift data are revolutionising our understanding of Gamma Ray Bursts. Since bursts fade rapidly, it is desirable to create and disseminate accurate light curves rapidly.
Gamma-ray burst (GRB) afterglows have provided important clues to the nature of these massive explosive events, providing direct information on nearby environment and indirect central engine that powers burst. We report discovery two bright x-ray flares in GRB afterglows, including a giant flare comparable total energy itself, each peaking minutes after These strong, rapid imply engines bursts long periods activity, with strong internal shocks continuing for hundreds seconds gamma-ray...
Aims. Pointed observations with XMM-Newton provide the basis for creating catalogues of X-ray sources detected serendipitously in each field. This paper describes creation and characteristics 2XMM catalogue.
We report on the analysis of a ~60 ksec XMM observation bright, narrow emission line quasar PG 1211+143. Absorption lines are seen in both EPIC and RGS spectra corresponding to H- He-like ions Fe, S, Mg, Ne, O, N C. The observed energies indicate an ionised outflow velocity ~24000 km s^-1. highest energy require column density N_H ~ 5 x 10^23 cm^-2, at ionisation parameter log(xi) 3.4. If origin this high lies matter being driven from inner disc, then flow is likely be optically thick within...
Thanks to the large collecting area (3 x ~1500 cm$^2$ at 1.5 keV) and wide field of view (30' across in full mode) X-ray cameras on board European Space Agency observatory XMM-Newton, each individual pointing can result detection hundreds sources, most which are newly discovered. Recently, many improvements XMM-Newton data reduction algorithms have been made. These include enhanced source characterisation reduced spurious detections, refined astrometric precision, greater net sensitivity...
With the first direct detection of merging black holes in 2015, era gravitational wave (GW) astrophysics began. A complete picture compact object mergers, however, requires an electromagnetic (EM) counterpart. We report ultraviolet (UV) and X-ray observations by Swift Nuclear Spectroscopic Telescope ARray (NuSTAR) EM counterpart binary neutron star merger GW170817. The bright, rapidly fading emission indicates a high mass ($\approx0.03$ solar masses) wind-driven outflow with moderate...
We present comprehensive multiwavelength observations of three gamma-ray bursts (GRBs) with durations several thousand seconds. demonstrate that these events are extragalactic transients; in particular we resolve the long-standing conundrum distance GRB 101225A (the "Christmas-day burst"), finding it to have a redshift z=0.847, and showing two apparently similar (GRB 111209A 121027A) lie at z=0.677 z=1.773 respectively. The systems show extremely unusual X-ray optical lightcurves, very...
We present a catalogue of nearly 3,000 submillimetre sources detected at 850um over ~5 square degrees surveyed as part the James Clerk Maxwell Telescope (JCMT) SCUBA-2 Cosmology Legacy Survey (S2CLS). This is largest survey its kind 850um, probing meaningful cosmic volume peak star formation activity and increasing sample size galaxies selected by an order magnitude. describe wide component S2CLS, which covers key extragalactic fields: UKIDSS-UDS, COSMOS, Akari-NEP, Extended Groth Strip,...
Sky surveys produce enormous quantities of data on extensive regions the sky. The easiest way to access this information is through catalogues standardised products. {\em XMM-Newton} has been surveying sky in X-ray, ultra-violet, and optical bands for 20 years. Survey Science Centre producing products facilitate serendipitous X-ray Using improved calibration enhanced software, we re-reduced all 14041 observations, which 11204 observations contained with at least one detection these created a...
We report the discovery of unusually bright long-duration gamma-ray burst (GRB), GRB 221009A, as observed by Neil Gehrels Swift Observatory (Swift), Monitor All-sky X-ray Image (MAXI), and Neutron Star Interior Composition Explorer Mission (NICER). This energetic was located relatively nearby (z = 0.151), allowing for sustained observations afterglow. The large luminosity low Galactic latitude (b 4.3 degrees) make 221009A a powerful probe dust in Milky Way. Using echo tomography we map...
We collate the results of recent high resolution X-ray spectroscopic observations 23 AGN, and use resulting information to try provide answers some main open questions about warm absorbers: where do they originate, what effect have on their host galaxies, is importance within energetics dynamics AGN system as a whole? find that absorbers nearby Seyferts certain QSOs are most likely originate in outflows from dusty torus, kinetic luminosity these accounts for well under 1% bolometric...
We present observations of the early X-ray emission for a sample 40 gamma-ray bursts (GRBs) obtained using Swift satellite which narrow-field instruments were pointed at burst within 10 minutes trigger. Using data from Burst Alert and X-Ray Telescopes, we show that light curve can be well described by an exponential relaxes into power law, often with flares superimposed. The transition time between law provides physically defined timescale duration. In most breaks to shallower decay first...
We show that all X-ray decay curves of GRBs measured by Swift can be fitted using one or two components both which have exactly the same functional form comprised an early falling exponential phase followed a power law decay. The 1st component contains prompt gamma-ray emission and initial 2nd appears later, has much longer duration is present for ~80% GRBs. It most likely arises from external shock eventually develops into afterglow. In remaining ~20% fades more slowly than dominates at...
We systematically analyze the prompt emission and early afterglow data of a sample 31 GRBs detected by {\em Swift} before September 2005, estimate GRB radiative efficiency. BAT's narrow band inhibits precise determination spectral parameters, we have developed method to these parameters with hardness ratio information. The shallow decay component commonly existing in X-ray afterglows, if interpreted as continuous energy injection external shock, suggests that efficiency previously derived...