Search Publications
Discovery of a single faint AGN in a large sample of z > 5 Lyman break galaxies
Lehnert, Matthew D.; Stanway, Elizabeth R.; Bremer, Malcolm N. +1 more
As part of a large spectroscopic survey of z > 5 Lyman break galaxies (LBGs), we have identified a single source which is clearly hosting an active galactic nucleus (AGN). Out of a sample of more than 50 spectroscopically confirmed R-band dropout galaxies at z ~ 5 and above, only J104048.6-115550.2 at z = 5.44 shows evidence for a high ionizati…
XMM-Newton unveils the type 2 nature of the BLRG 3C 445
Guainazzi, Matteo; Ponti, Gabriele; Grandi, Paola +1 more
We present an observation of XMM-Newton that unambiguously reveals the `Seyfert 2' nature of the broad line radio galaxy 3C 445. For the first time the soft excess of this source has been resolved. It consists of unobscured scattered continuum flux and emission lines, likely produced in a warm photoionized gas near the pole of an obscuring torus. …
An XMM-Newton observation of the neutron star X-ray transient 2S 1803-245 in quiescence
Wijnands, R.; Homan, J.; Cornelisse, R.
We observed the neutron star X-ray transient 2S 1803-245 in quiescence with the X-ray satellite XMM-Newton, but did not detect it. An analysis of the X-ray bursts observed during the 1998 outburst of 2S 1803-245 gives an upper limit to the distance of <=7.3 kpc, leading to an upper limit on the quiescent 0.5-10 keV X-ray luminosity of <=2.8 …
The X-ray spectra of the flaring and quiescent states of YZ CMi observed by XMM-Newton
Raassen, A. J. J.; Güdel, M.; Mitra-Kraev, U.
We analyse the X-ray spectrum of the active late-type star YZ CMi (M4.5V); for quiescent as well as active stages, we derive emission measure (EM) distributions, elemental abundances, and electron temperatures and densities, which are in turn used to estimate flare loop lengths as well as coronal magnetic field strengths.
YZ CMi was observed …Star formation history and evolution of gas-rich dwarf galaxies in the Centaurus A group
Freeman, K. C.; Gallagher, J. S.; Disney, M. J. +4 more
We analyse the properties of three unusual dwarf galaxies in the Centaurus A group discovered with the HIPASS survey. From their optical morphology, they appear to be low surface brightness dwarf spheroidals, yet they are gas rich (MHI/LB > 1) with gas-mass-to-stellar light ratios larger than typical dwarf irregular galaxi…
A search for the third lensed image in JVAS B1030+074
Zhang, M.; Jackson, N.; Browne, I. W. A. +1 more
Central gravitational image detection is very important for the study of the mass distribution of the inner parts (~100 pc) of lens galaxies. However, the detection of such images is extremely rare and difficult. We present a 1.7-GHz High Sensitivity Array (HSA) observation of the double-image radio lens system B1030+074. The data are combined wit…
Structure and clumping in the fast wind of NGC6543
Prinja, R. K.; Fullerton, A. W.; Massa, D. L. +2 more
Far-ultraviolet spectroscopy from the FUSE satellite is analysed to uniquely probe spatial structure and clumping in the fast wind of the central star of the H-rich planetary nebula NGC 6543 (HD 164963). Time-series data of the unsaturated PV λλ1118, 1128 resonance line P Cygni profiles provide a very sensitive diagnostic of variable wind conditio…
Iron abundances of B-type post-asymptotic giant branch stars in globular clusters: Barnard29 in M13 and ROA5701 in ωCen
Dufton, P. L.; Keenan, F. P.; Thompson, H. M. A. +4 more
High-resolution optical and ultraviolet (UV) spectra of two B-type post-asymptotic giant branch (post-AGB) stars in globular clusters, Barnard29 in M13 and ROA5701 in ωCen, have been analysed using model atmosphere techniques. The optical spectra have been obtained with FEROS on the ESO 2.2-m telescope and the 2d-Coudé spectrograph on the 2.7-m Mc…
The luminous X-ray hotspot in 4C74.26: synchrotron or inverse-Compton emission?
Fabian, A. C.; Erlund, M. C.; Ballantyne, D. R. +2 more
We report the discovery of an X-ray counterpart to the southern radio hotspot of the largest-known radio quasar 4C74.26 (whose redshift is z = 0.104). Both XMM-Newton and Chandra images reveal the same significant (10arcsec i.e. 19kpc) offset between the X-ray hotspot and the radio hotspot imaged with MERLIN. The peak of the X-ray emission may be …
An XMM-Newton view of M101 - III. Diffuse X-ray emission
Read, A. M.; Warwick, R. S.; Roberts, T. P. +2 more
We present a study of the X-ray properties of the nearby face-on Scd spiral galaxy M101 based on recent XMM-Newton observations. In this third and final paper in the present series, we focus on the spatial and spectral properties of the residual emission, after excluding bright X-ray sources with LX > 1037ergs-1…