Search Publications
A multimission catalogue of ultraluminous X-ray source candidates
Earnshaw, H. P.; Roberts, T. P.; Mateos, S. +4 more
We present a new, multimission catalogue of ultraluminous X-ray source (ULX) candidates, based on recent data releases from each of the XMM-Newton, Swift, and Chandra observatories (the 4XMM-DR10, 2SXPS, and CSC2 catalogues, respectively). This has been compiled by cross-correlating each of these X-ray archives with a large sample of galaxies prim…
Do quasar X-ray and UV flux measurements provide a useful test of cosmological models?
Khadka, Narayan; Ratra, Bharat
The recent compilation of quasar (QSO) X-ray and ultraviolet (UV) flux measurements include QSOs that appear to not be standardizable via the X-ray luminosity and UV luminosity (LX-LUV) relation and so should not be used to constrain cosmological model parameters. Here, we show that the largest of seven sub-samples in this co…
All-purpose, all-sky photometric redshifts for the Legacy Imaging Surveys Data Release 8
Duncan, Kenneth J.
In this paper, we present photometric redshift (photo-z) estimates for the Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Surveys, currently the most sensitive optical survey covering the majority of the extragalactic sky. Our photo-z methodology is based on a machine-learning approach, using sparse Gaussian processes augmented with Ga…
The effect of returning radiation on relativistic reflection
Reynolds, C. S.; Dauser, T.; Wilms, J. +5 more
We study the effect of returning radiation on the shape of the X-ray reflection spectrum in the case of thin accretion discs. We show that the returning radiation mainly influences the observed reflection spectrum for a large black hole spin (a > 0.9) and a compact primary source of radiation close to the black hole at height h < 5rg
Polarization constraints on the X-ray corona in Seyfert Galaxies: MCG-05-23-16
Antonelli, L. A.; Costa, E.; Bianchi, S. +97 more
We report on the first observation of a radio-quiet active galactic nucleus (AGN) in polarized X-rays: the Seyfert 1.9 galaxy MCG-05-23-16. This source was pointed at with the Imaging X-ray Polarimetry Explorer (IXPE) starting on 2022 May 14 for a net observing time of 486 ks, simultaneously with XMM-Newton (58 ks) and NuSTAR (83 ks). A polarizati…
Mysterious odd radio circle near the large magellanic cloud - an intergalactic supernova remnant?
Haberl, F.; Umana, G.; Hill, T. +48 more
We report the discovery of J0624-6948, a low-surface brightness radio ring, lying between the Galactic Plane and the large magellanic cloud (LMC). It was first detected at 888 MHz with the Australian Square Kilometre Array Pathfinder (ASKAP), and with a diameter of ~196 arcsec. This source has phenomenological similarities to odd radio circles (OR…
Radio fossils, relics, and haloes in Abell 3266: cluster archaeology with ASKAP-EMU and the ATCA
Diego, J. M.; Tasse, C.; Eckert, D. +21 more
Abell 3266 is a massive and complex merging galaxy cluster that exhibits significant substructure. We present new, highly sensitive radio continuum observations of Abell 3266 performed with the Australian Square Kilometre Array Pathfinder (0.8-1.1 GHz) and the Australia Telescope Compact Array (1.1-3.1 GHz). These deep observations provide new ins…
Dwarf AGNs from Optical Variability for the Origins of Seeds (DAVOS): insights from the dark energy survey deep fields
Bacon, D.; Shen, Yue; Smith, M. +69 more
We present a sample of 706, z < 1.5 active galactic nuclei (AGNs) selected from optical photometric variability in three of the Dark Energy Survey (DES) deep fields (E2, C3, and X3) over an area of 4.64 deg2. We construct light curves using difference imaging aperture photometry for resolved sources and non-difference imaging PSF pho…
INTEGRAL/IBIS 17-yr hard X-ray all-sky survey
Tsygankov, Sergey S.; Lutovinov, Alexander A.; Krivonos, Roman A. +3 more
The International Gamma-Ray Astrophysics Laboratory (INTEGRAL), launched in 2002, continues its successful work in observing the sky at energies E > 20 keV. The legacy of the mission already includes a large number of discovered or previously poorly studied hard X-ray sources. The growing INTEGRAL archive allows one to conduct an all-sky survey…
The incidence of X-ray selected AGN in nearby galaxies
Birchall, Keir L.; Watson, M. G.; Aird, J. +1 more
We present the identification and analysis of an unbiased sample of active galactic nuclei (AGN) that lie within the local galaxy population. Using the MPA-JHU catalogue (based on SDSS DR8) and 3XMM DR7 we define a parent sample of 25 949 local galaxies (z ≤ 0.33). After confirming that there was strictly no AGN light contaminating stellar mass an…