Search Publications
XMM-Newton observations of the heavily absorbed Seyfert 1 galaxy IC 4329A
Kaastra, J. S.; Behar, E.; Sako, M. +5 more
We detect seven distinct absorbing systems in the high-resolution X-ray spectrum of the Seyfert 1 galaxy IC 4329A, taken with XMM-Newton. Firstly we detect absorption due to cold gas in our own Galaxy and warm gas in the Galactic halo or the Local Group. This local warm gas is only detected through O VII absorption, from which we deduce a temperat…
Optical and near-infrared integral field spectroscopy of the SCUBA galaxy N2 850.4
Ivison, R. J.; Smail, Ian; Swinbank, A. M. +7 more
We present optical and near-infrared integral field spectroscopy of the SCUBA galaxy SMMJ163650.43+405734.5 (ELAIS N2 850.4) at z= 2.385. We combine Lyα and Hα emission line maps and velocity structure with high-resolution HST ACS and NICMOS imaging to probe the complex dynamics of this vigorous starburst galaxy. The imaging data show a complex mo…
Extragalactic Source Counts in the 20-50 keV Energy Band from the Deep Observation of the Coma Region by INTEGRAL IBIS
Sunyaev, R.; Krivonos, R.; Churazov, E. +3 more
We present the analysis of serendipitous sources in a deep, 500 ks, hard X-ray observation of the Coma Cluster region with the IBIS instrument on board INTEGRAL. In addition to the Coma Cluster, the final 20-50 keV image contains 12 serendipitous sources with statistical significance >4 σ. We use these data (after correcting for expected number…
The cloud structure of the jovian atmosphere as seen by the Cassini/CIRS experiment
Flasar, F. Michael; Conrath, Barney J.; Gierasch, Peter J. +1 more
We analyze the thermal infrared spectra of Jupiter obtained by the Cassini-CIRS instrument during the 2000 flyby to infer temperature and cloud density in the jovian stratosphere and upper troposphere. We use an inversion technique to derive zonal mean vertical profiles of cloud absorption coefficient and optical thickness from a narrow spectral w…
XMM-Newton study of the lensing cluster of galaxies CL 0024+17
Zhang, Y. -Y.; Böhringer, H.; Forman, W. +2 more
We present a detailed gravitational mass measurement based on the XMM-Newton imaging spectroscopy analysis of the lensing cluster of galaxies CL 0024+17 at z=0.395. The emission appears approximately symmetric. However, on the scale of r ∼ 3.3' some indication of elongation is visible in the northwest-southeast (NW-SE) direction from th…
The Tully-Fisher relation of distant cluster galaxies
Milvang-Jensen, B.; Aragón-Salamanca, A.; Bamford, S. P. +1 more
We have measured maximum rotation velocities (Vrot) for a sample of 111 emission-line galaxies with 0.1 <~z<~ 1, observed in the fields of six clusters. From these data we construct `matched' samples of 58 field and 22 cluster galaxies, covering similar ranges in redshift (0.25 <=z<= 1.0) and luminosity (MB<=-1…
Optical and infrared signatures of ultra-luminous X-ray sources
Copperwheat, Christopher; Cropper, Mark; Soria, Roberto +1 more
We have constructed a model to describe the optical emission from ultra-luminous X-ray sources (ULXs). We assume a binary model with a black hole accreting matter from a Roche lobe filling companion star. We consider the effects of radiative transport and radiative equilibrium in the irradiated surfaces of both the star and a thin accretion disc. …
The dark lane of the planetary nebula NGC 6302*†
Waters, L. B. F. M.; Sahai, R.; Zijlstra, A. A. +4 more
The butterfly-shaped planetary nebula, NGC 6302, shows a unique, dense equatorial dark lane, which is presumably a dusty disc, obscuring an unobserved, very hot central star. We trace the structure of this disc using Hubble Space Telescope Hα and [N II] images, Very Large Telescope L-and M-band images at 0.4-arcsec resolution, including Brα and po…
A quantum electrodynamics model for non-thermal emission from soft gamma repeaters and anomalous X-ray pulsars
Hernquist, Lars; Heyl, Jeremy S.
Previously, we showed that, owing to effects arising from quantum electrodynamics (QED), magnetohydrodynamic fast modes of sufficient strength will break down to form electron-positron pairs while traversing the magnetospheres of strongly magnetized neutron stars. The bulk of the energy of the fast mode fuels the development of an electron-positro…
The Connection between the Narrow-Line Region and the UV Absorbers in Seyfert Galaxies
Kraemer, S. B.; Crenshaw, D. M.
We present evidence that the outflowing UV absorbers in Seyfert 1 galaxies arise primarily in their inner narrow- (emission-) line regions (NLRs), based on similarities in their locations, kinematics, and physical conditions. Hubble Space Telescope observations show that nearly all Seyfert galaxies have bright, central knots of [O III] emission in…