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On the influence of the companion star in Eta Carinae: 2D radiative transfer modelling of the ultraviolet and optical spectra
Hillier, D. John; Weigelt, Gerd; Madura, Thomas I. +1 more
We present two-dimensional (2D) radiative transfer modelling of the Eta Carinae binary system accounting for the presence of a wind-wind collision (WWC) cavity carved in the optically thick wind of the primary star. By comparing synthetic line profiles with spectra obtained with the Hubble Space Telescope/Space Telescope Imaging Spectrograph near …
A combined optical and X-ray study of unobscured type 1 active galactic nuclei - II. Relation between X-ray emission and optical spectra
Done, Chris; Ward, Martin; Jin, Chichuan
In this second paper in a series of three, we study the properties of the various emission features and underlying continuum in the optical spectra of type 1 active galactic nuclei (AGNs) by using the unobscured hard X-ray emission as a diagnostic. We introduce the use of the 'correlation spectrum technique' (CST) for the first time. We use this t…
Large-scale Motions in the Perseus Galaxy Cluster
Simionescu, A.; Fabian, A. C.; Allen, S. W. +6 more
By combining large-scale mosaics of ROSAT PSPC, XMM-Newton, and Suzaku X-ray observations, we present evidence for large-scale motions in the intracluster medium of the nearby, X-ray bright Perseus Cluster. These motions are suggested by several alternating and interleaved X-ray bright, low-temperature, low-entropy arcs located along the east-west…
Transient dust in warm debris disks. Detection of Fe-rich olivine grains
Mutschke, H.; Ábrahám, P.; Henning, Th. +4 more
Context. Debris disks trace remnant reservoirs of leftover planetesimals in planetary systems. In the past years, a handful of "warm" debris disks have been discovered in which emission in excess starts in the mid-infrared. An interesting subset of these warm debris disks shows emission features in mid-infrared spectra, which points towards the pr…
A DEBRIS disk around the planet hosting M-star GJ 581 spatially resolved with Herschel
Duchêne, G.; Dent, W. R. F.; Bryden, G. +17 more
Debris disks have been found primarily around intermediate and solar mass stars (spectral types A-K) but rarely around low mass M-type stars. We have spatially resolved a debris disk around the remarkable M3-type star GJ 581 hosting multiple planets using deep PACS images at 70, 100 and 160 µm as part of the DEBRIS Program on the Herschel Sp…
XMM-Newton observation of 4U 1820-30. Broad band spectrum and the contribution of the cold interstellar medium
Waters, L. B. F. M.; Kaastra, J. S.; Costantini, E. +6 more
We present an analysis of the bright X-ray binary 4U 1820-30, thet is based mainly on XMM-Newton-RGS data, in addition to complementary data from XMM-Newton-EPIC-pn, INTEGRAL, and Chandra-HETG, to investigate different aspects of the source. The broad band continuum is fitted well by a classical combination of black body and Comptonized emission. …
Instantaneous Starburst of the Massive Clusters Westerlund 1 and NGC 3603 YC
Henning, Thomas; Da Rio, Nicola; Gennaro, Mario +9 more
We present a new method to determine the age spread of resolved stellar populations in a starburst cluster. The method relies on a two-step process. In the first step, kinematic members of the cluster are identified based on multi-epoch astrometric monitoring. In the second step, a Bayesian analysis is carried out, comparing the observed photometr…
Herschel/HIFI Discovery of HCl+ in the Interstellar Medium
Falgarone, E.; Godard, B.; Teyssier, D. +12 more
The radical ion HCl+, a key intermediate in the chlorine chemistry of the interstellar gas, has been identified for the first time in the interstellar medium with the Herschel Space Observatory's Heterodyne Instrument for the Far-Infrared. The ground-state rotational transition of H35Cl+, 2Π3/2
Binaries among Debris Disk Stars
Zuckerman, B.; Rodriguez, David R.
We have gathered a sample of 112 main-sequence stars with known debris disks. We collected published information and performed adaptive optics observations at Lick Observatory to determine if these debris disks are associated with binary or multiple stars. We discovered a previously unknown M-star companion to HD 1051 at a projected separation of …
A study of X-ray flares - II. RS CVn-type binaries
Pandey, J. C.; Singh, K. P.
We present an analysis of seven flares detected from five RS CVn-type binaries (UZ Lib, σ Gem, λ And, V711 Tau and EI Eri) observed with XMM-Newton observatory. The quiescent state X-ray luminosities in the energy band of 0.3-10.0 keV of these stars were found to be 1030.7-30.9 erg s-1. The exponential decay time in all the s…