Search Publications
Post-glitch variability in the anomalous X-ray pulsar 1RXSJ170849.0-400910
Haberl, F.; Stella, L.; Rea, N. +5 more
Here we report on the first XMM-Newton observation of the anomalous X-ray pulsar 1RXSJ170849.0-400910. The source was observed in 2003 August, and was found at a flux level factor of about 2 lower than previous observations. Moreover, a significant spectral evolution appears to be present, the source exhibiting a much softer spectrum than in the p…
Chandra and XMM-Newton observations of NGC 6251
Hardcastle, M. J.; Croston, J. H.; Birkinshaw, M. +2 more
We present new X-ray observations of the nucleus, jet and extended emission of the nearby radio galaxy NGC 6251 using the Chandra/ACIS-S camera, together with a reanalysis of archival Chandra/ACIS-I and XMM-Newton/EPIC data. We find that the nuclear X-ray spectrum is well fitted with an absorbed power law, and that there is tentative, but not high…
XMM-Newton EPIC observations of the ultraluminous X-ray source NGC 5204 X-1
Warwick, R. S.; Roberts, T. P.; Ward, M. J. +2 more
We present the results of two XMM-Newton observations of the ultraluminous X-ray source NGC 5204 X-1. The EPIC spectra are well fitted by the standard spectral model of a black hole X-ray binary, comprising a soft multicolour disc blackbody component plus a harder power-law continuum. The cool (kTin~ 0.2 keV) inner-disc temperature requ…
The giant Hα/X-ray filament in the cluster of galaxies A1795
Fabian, A. C.; Sanders, J. S.; Crawford, C. S.
The cluster of galaxies A1795 hosts a 46 kpc long filament at its core, which is clearly visible in the light of Hα and X-ray emission. We present optical slit spectroscopy and deeper Chandra X-ray data of the filament. The optical spectra reveal that the bulk of the filament is quiescent (with σ < 130 km s-1), although considerable …
A Chandra and XMM-Newton study of the wide-angle tail radio galaxy 3C465
Hardcastle, M. J.; Worrall, D. M.; Sakelliou, I.
We have observed the prototypical wide-angle tail (WAT) radio galaxy 3C465 with Chandra and XMM-Newton. X-ray emission is detected from the active nucleus and the inner radio jet, as well as a small-scale, cool component of thermal emission, a number of the individual galaxies of the host cluster (Abell 2634), and the hotter thermal emission from …
A bar signature and central disc in the gaseous and stellar velocity fields of NGC 5448
Emsellem, Eric; van de Ven, Glenn; Peletier, Reynier F. +4 more
We analyse Spectrographic Areal Unit for Research on Optical Nebulae (SAURON) kinematic maps of the inner kiloparsec of the early-type (Sa) barred spiral galaxy NGC 5448. The observed morphology and kinematics of the emission-line gas is patchy and perturbed, indicating clear departures from circular motion. The kinematics of the stars is more reg…
An XMM-Newton observation of Mkn 3 - a Seyfert galaxy just over the edge
Page, K. L.; Pounds, K. A.
A 100-ks XMM-Newton observation of the nearby Seyfert 2 galaxy Mkn 3 offers a unique opportunity to explore the complexity of its X-ray spectrum. We find the ~3-8 keV continuum to be dominated by reflection from cold matter, with fluorescent K-shell lines detected from Ni, Fe, Ca, Ar, S, Si and Mg. At higher energies an intrinsic power-law continu…
Supermassive black hole mass measurements for NGC 1300 and 2748 based on Hubble Space Telescope emission-line gas kinematics
Marconi, A.; Capetti, A.; Carollo, C. M. +18 more
We present Space Telescope Imaging Spectrograph emission-line spectra of the central regions of the spiral galaxies NGC 1300 and 2748. From the derived kinematics of the nuclear gas we have found evidence for central supermassive black holes in both galaxies. The estimated masses of the black holes in NGC 1300 and 2748 are (6.6+6.3…
A deep survey of brown dwarfs in Orion with Gemini
Tamura, M.; Lucas, P. W.; Roche, P. F.
We report the results of a deep near-infrared (JHK) survey of the outer parts of the Trapezium Cluster with Gemini South/Flamingos. 396 sources were detected in a 26 arcmin2 area, including 138 brown dwarf candidates, defined as M < 0.075 Msolar for an assumed age of 1 Myr. Only 33 of the brown dwarf candidates are planeta…
Self-regulated active galactic nuclei heating in elliptical galaxies
Kawata, D.; Gibson, B. K.
We study the effect of active galactic nuclei (AGN) heating on the chemodynamical evolution of elliptical galaxies and their X-ray and optical properties using high-resolution Λ-dominated cold dark matter cosmological simulations. Our model considers an AGN as being `active' when a convergent gas inflow condition exists within the nucleus of a gal…