Search Publications
Pulsed thermal emission from the accreting pulsar XMMU J054134.7-682550
Audard, M.; Walter, R.; Lanz, T. +1 more
Aims: Soft X-ray excesses have been detected in several Be/X-ray binaries and interpreted as the signature of hard X-ray reprocessing in the inner accretion disk. The system XMMU J054134.7-682550, located in the LMC, featured a giant Type II outburst in August 2007. The geometry of this system can be understood by studying the response of the soft…
The low-mass stellar-mass functions of rich, compact clusters in the Large Magellanic Cloud
de Grijs, R.; Hu, Y.; Liu, Q. +2 more
Context: The LMC is an ideal environment for studying stellar MFs, because it contains a large population of compact clusters at different evolutionary stages. We aim to obtain constraints on the initial MFs (IMFs) of our sample clusters on the basis of their present-day MFs, combined with our understanding of their dynamical and photometric evolu…
Weak lensing density profiles and mass reconstructions of the galaxy clusters Abell 1351 and Abell 1995
Dahle, H.; Schirmer, M.; Holhjem, K.
Aims: The aim of the present work is to study the overall mass distribution of the galaxy clusters Abell 1351 and Abell 1995 using weak gravitational lensing. These clusters have a very different mass structure and dynamical state and are the two extremes from a larger sample of 38 X-ray luminous clusters of similar size and redshift.
Methods:…
On the massive star content of the nearby dwarf irregular Wolf-Rayet galaxy IC 4662
Crowther, P. A.; Bibby, J. L.
Aims: We investigate the massive stellar content of the nearby dwarf irregular Wolf-Rayet galaxy IC 4662, and consider its global star forming properties in the context of other metal-poor galaxies, namely the SMC, IC 10 and NGC 1569.
Methods: Very Large Telescope/FORS2 imaging and spectroscopy plus archival Hubble Space Telescope/ACS imaging …
Bursting behavior of the Galactic center faint X-ray transient GRS 1741.9-2853
Grosso, N.; Porquet, D.; Bozzo, E. +6 more
Aims: The neutron star low-mass X-ray binary GRS 1741.9-2853 is a known type-I burster at the Galactic center. It is transient, faint, and located in a very crowded region, only 10' from the supermassive black hole Sgr A^star. Therefore, its bursting behavior has been poorly studied so far. In particular, its persistent emission has rarely been de…
The very short supersoft X-ray state of the classical nova M31N 2007-11a
Della Valle, M.; Pietsch, W.; Haberl, F. +9 more
Context: Short supersoft X-ray source (SSS) states (durations ≤100 days) of classical novae (CNe) indicate massive white dwarfs that are candidate progenitors of supernovae type Ia.
Aims: We carry out a dedicated optical and X-ray monitoring program of CNe in the bulge of M 31.
Methods: We discovered M31N 2007-11a and determined its optica…
Maximum-likelihood detection of sources among Poissonian noise
Stewart, I. M.
A maximum likelihood (ML) technique for detecting compact sources in images of the X-ray sky is examined. Such images, in the relatively low exposure regime accessible to present X-ray observatories, exhibit Poissonian noise at background flux levels. A variety of source detection methods are compared via Monte Carlo, and the ML detection method i…
Multiwavelength analysis of a solar quiet region
Heinzel, P.; Schwartz, P.; Tziotziou, K. +1 more
Context: We examine oscillatory phenomena in a solar network region from multi-wavelength observations obtained by the ground-based Dutch Open Telescope (DOT) and by the Coronal Diagnostic Spectrometer (CDS) on the spacecraft Solar and Heliospheric Observatory (SoHO). The observations were obtained during a coordinated observing campaign in Octobe…
Abundances in planetary nebulae: NGC 2792
Pottasch, S. R.; Bernard-Salas, J.; Surendiranath, R. +1 more
The mid-infrared spectrum of the rather circular planetary nebula
The FERRUM project: transition probabilities for forbidden lines in [Fe II] and experimental metastable lifetimes
Nilsson, H.; Hartman, H.; Gurell, J. +5 more
Context: Accurate transition probabilities for forbidden lines are important diagnostic parameters for low-density astrophysical plasmas. In this paper we present experimental atomic data for forbidden [ion{Fe}{ii}] transitions that are observed as strong features in astrophysical spectra.
Aims: We measure lifetimes for the 3d^6(^3G)4s a ^4G{…