A5103129445- Astrophysical Phenomena and Observations
- Galaxies: Formation, Evolution, Phenomena
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Astrophysics and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Pulsars and Gravitational Waves Research
- X-ray Spectroscopy and Fluorescence Analysis
- Astrophysics and Star Formation Studies
- High-pressure geophysics and materials
- Astro and Planetary Science
- Superconducting Materials and Applications
- Mechanics and Biomechanics Studies
- History and Developments in Astronomy
- Adaptive optics and wavefront sensing
- Nuclear Physics and Applications
- Advanced X-ray Imaging Techniques
- Magnetic confinement fusion research
- Particle Detector Development and Performance
- Laser-Plasma Interactions and Diagnostics
- Radiation Detection and Scintillator Technologies
- Security and Verification in Computing
- Geophysics and Gravity Measurements
- Scientific Measurement and Uncertainty Evaluation
University of Leicester
2010-2024
Fisk University
2000-2021
Park University
2021
University of Wisconsin–Oshkosh
2020
University of Vermont
2013
We present the most up-to-date X-ray luminosity function (XLF) and absorption of Active Galactic Nuclei (AGNs) over redshift range from 0 to 5, utilizing largest, highly complete sample ever available obtained surveys performed with Swift/BAT, MAXI, ASCA, XMM-Newton, Chandra, ROSAT. The combined sample, including that Subaru/XMM-Newton Deep Survey, consists 4039 detections in soft (0.5--2 keV) and/or hard ($>2$ band. utilize a maximum likelihood method reproduce count-rate versus...
We present a highly complete and reliable mid-infrared (MIR) colour selection of luminous AGN candidates using the 3.4, 4.6, 12 um bands WISE survey. The MIR wedge was defined wide-angle Bright Ultra-Hard XMM-Newton Survey (BUXS), one largest flux-limited samples bright (f(4.5-10 keV)>6x10^{-14} erg cm^-2 s^-1) "ultra-hard" (4.5-10 keV) X-ray selected to date. BUXS includes 258 objects detected over total sky area 44.43 deg^2 which 251 are spectroscopically identified classified, with 145...
We present the X-ray source catalog in Subaru/XMM-Newton deep survey. A continuous area of 1.14 deg^2 centered at R.A. = 02h18m and Dec. -05d is mapped by seven pointings with XMM-Newton covering 0.2-10 keV band. From combined images EPIC pn MOS cameras, we detect 866, 1114, 645, 136 sources sensitivity limits 6x10^{-16}, 8x10^{-16}, 3x10^{-15}, 5x10^{-15} erg cm^{-2} s^{-1} 0.5-2, 0.5-4.5, 2-10, 4.5-10 bands, respectively, detection likelihood >= 7 (corresponding to a confidence level...
We cross-correlate the largest available Mid-Infrared (WISE), X-ray (3XMM) and Radio (FIRST+NVSS) catalogues to define MIXR sample of AGN star-forming galaxies. pre-classify sources based on their positions WISE colour/colour plot, showing that triple selection is extremely effective diagnose star formation activity individual populations, even a flux/magnitude basis, extending diagnostics objects with luminosities redshifts from SDSS DR12. recover radio/mid-IR correlation great accuracy,...
In this work we present a robust quantification of X-ray selected AGN in local ($z \leq 0.25$) dwarf galaxies ($M_\mathrm{*} 3 \times 10^9 \mathrm{M_\odot}$). We define parent sample 4,331 found within the footprint both MPA-JHU galaxy catalogue (based on SDSS DR8) and 3XMM DR7, performed careful review data to remove misidentifications produced 61 that exhibit nuclear activity indicative an AGN. examine optical emission line ratios our find diagnostics fail identify 85% sources. then...
view Abstract Citations (186) References (47) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS X-ray emission from M 82. Watson, M. G. ; Stanger, V. Griffiths, R. E. An study of M82 with the Einstein Observatory imaging instruments is presented. Observations High Resolution Imager show a luminous, extended source centered on M82. The most intense feature in image has dimensions about 30-60 arcsec and corresponds quite closely to optically brightest region near...
We present the results of a search for galaxy clusters in Subaru-XMM Deep Field. reach depth total cluster flux 0.5-2 keV band 2x10^{-15} ergs cm^{-2} s^{-1} over one widest XMM-Newton contiguous raster surveys, covering an area 1.3 square degrees. Cluster candidates are identified through wavelet detection extended X-ray emission. The red sequence technique allows us to identify 57 candidates. report on progress with spectroscopic follow-up and derive their properties based luminosity...
We present here "The XMM-Newton Bright Serendipitous Survey", composed of two flux-limited samples: the Source Sample (BSS, hereafter) and "Hard" (HBSS, having a flux limit erg cm-2 s-1 in 0.5-4.5 keV 4.5-7.5 energy band, respectively. After discussing main goals this project survey strategy, we basic data on complete sample 400 X-ray sources (389 them belong to BSS, 67 HBSS with 56 common) derived from analysis 237 suitable fields (211 for HBSS). At cover area 28.10 (25.17 HBSS) sq. deg....
Context. Our knowledge of the properties AGN, especially those optical type-2 objects, is very incomplete. Because extragalactic source count distributions are dependent on cosmological and statistical they provide a direct method investigating underlying populations.
We present the distributions of geometrical covering factors active galactic nuclei (AGNs) dusty tori (f2) using an X-ray selected complete sample 227 AGN drawn from Bright Ultra-hard XMM-Newton Survey. The have z 0.05 to 1.7, 2-10 keV luminosities between 10^42 and 10^46 erg/s Compton-thin absorption. Employing data UKIDSS, 2MASS Wide-field Infrared Survey Explorer in a previous work we determined rest-frame 1-20 microns continuum emission torus which model here with clumpy models Nenkova...
The distribution of 2–6 keV X-ray emission in the galactic plane first and fourth quadrants has been measured a series scanning observations with medium-energy proportional counters on EXOSAT. results are presented as contour maps form catalogue 70 discrete sources.
This paper describes a comparative study of all the intermediate polars observed by EXOSAT. We present X-ray pulse profiles each source and show that, in cases, modulation can be described terms an increasing depth with decreasing energy. By considering phase-resolved spectra, we that cannot due to simple phase dependent absorption alone, but models which combine photoelectric effect self occultation produce explain data. In addition, using partial covering emission region improved fit...
Optical and ultraviolet observations are presented of the 1979 outburst recurrent nova U Sco. For first time evolution through is documented photometrically spectroscopically. Lines following ions identified: H I, He II, C IV, N III, V, O VI Si IV. No forbidden lines were observed. Mg I was seen in absorption at a late stage decline. The Balmer have broad narrow components which change with time. There evidence that nitrogen overabundant respect to carbon helium hydrogen number ratio about 2.
Context.Recent results have revised upwards the total X-ray background (XRB) intensity below ~10 keV, therefore an accurate determination of source counts is needed. There are also contradictory on clustering selected sources.
We present the identification and analysis of an unbiased sample AGN that lie within local galaxy population. Using MPA-JHU catalogue (based on SDSS DR8) 3XMM DR7 we define a parent 25,949 galaxies ($z \leq 0.33$). After confirming there was strictly no light contaminating stellar mass star-formation rate calculations, identified 917 with central, excess X-ray emission likely originating from AGN. analysed their optical lines using BPT diagnostic confirmed such techniques are more effective...
We present the results of ROSAT pointed observations AM Her stars AN UMa and MR Ser. was in a high-brightness state. examine its soft X-ray light curve, fit spectrum with two-component model consisting an absorbed blackbody harder thermal bremsstrahlung distribution. Ser found to be low-brightness state, had which well fitted single-component, model.
We present the first results from XMM–Newton Galactic Plane Survey (XGPS). In phase of programme, 22 pointings were used to cover a region approximately 3 deg2 between 19° and 22° in longitude ±0.6° latitude. total we have resolved over 400 point X-ray sources, at ≥ 5σ significance, down flux limit ∼2 × 10−14 erg s−1 cm−2 (2–10 keV). The sources exhibit very wide range spectral hardness, with interstellar absorption identified as major influence. source populations detected soft (0.4–2 keV)...
We describe the number counts and spatial distribution of 239 Distant Red Galaxies (DRGs), selected from Early Data Release UKIDSS Ultra Deep Survey. The DRGs are identified by their very red infrared colours with (J-K)AB>1.3, over 0.62 sq degree to a 90% completeness limit KAB~20.7. This is first time large sample bright has been studied within contiguous area, we provide measurements clustering. population shows strong angular clustering, intermediate between those K-selected field...
We discuss the broad band X-ray properties of one largest samples selected type-1 AGN to date (487 objects in total), drawn from XMM-Newton Wide Angle Survey. The cover 2-10 keV luminosities ~10^{42}-10^{45} erg s^{-1} and are detected up redshift ~4. constrain overall continuum, soft excess absorption, along with their dependence on luminosity we implications for models emission. constrained mean spectral index continuum <Gamma>=1.96+-0.02 intrinsic dispersion sigma=0.27_{-0.02}^{+0.01}....
In order to investigate the growth of super-massive black holes (SMBHs), we construct hole mass function (BHMF) and Eddington ratio distribution (ERDF) X-ray-selected broad-line AGNs at z~1.4 in Subaru XMM-Newton Deep Survey field. this redshift range, a significant part accretion SMBHs is thought be taking place. Black masses are estimated using width broad MgII line 3000A monochromatic luminosity. We supplement FWHM values with Ha obtained from our NIR spectroscopic survey. Using redshifts...
By comparing the orbital period distributions of black hole and neutron star low-mass X-ray binaries (LMXBs) in Ritter–Kolb catalogue we show that there is statistical evidence for a dearth systems at short periods (Porb < 4 h). This could either be due to true divergence these two types system, or LMXBs being preferentially hidden from view periods. We explore latter possibility, by investigating whether concealed switch radiatively inefficient accretion low luminosities. The peak...