Search Publications
Opacity in the upper atmospheres of active stars. II. AD Leonis
Christian, D. J.; Mathioudakis, M.; Bloomfield, D. S. +4 more
We present FUV and UV spectroscopic observations of AD Leonis, with the aim of investigating opacity effects in the transition regions of late-type stars. The C III lines in FUSE spectra show significant opacity during both the quiescent and flaring states of AD Leonis, with up to 30% of the expected flux being lost during the latter. Other FUSE e…
The proper motion of the isolated neutron star RX J1605.3+3249
de Luca, A.; Mignani, R. P.; Zane, S. +1 more
Aims.We present a new optical observation of the X-ray dim isolated neutron star RX J1605.3+3249, performed in 2005 with the Wide Field Channel (WFC) of the Advanced Camera for Surveys (ACS) on board Hubble Space Telescope, aimed at measuring the neutron star proper motion.
Methods: .We have compared the target position with the one measured i…
Nobeyama radio heliograph observations of RHESSI microflares
Kundu, M. R.; Shibasaki, K.; Garaimov, V. I. +2 more
Aims.We present a summary of the analysis of thirty microflares, observed simultaneously by the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) in hard X-rays and by Nobeyama RadioHeliograph (NoRH) in microwaves (17 GHz).
Methods: .We used microflares observed by RHESSI in the energy range 3-25 keV, and for larger events, up to 35 keV.…
Observations of the coronal dynamics associated with solar radio spike burst emission
Aurass, H.; Khan, J. I.
We present the results of an analysis of multi-wavelength data for a solar radio spike burst event which was observed on 1997 November 14 by the Solar Radio Spectrometers of the Astrophysikalisches Institut Potsdam (AIP). Using radio imaging data from the Nançay Radioheliograph we are able to determine the location of the spike burst emission site…
Distribution of extinction and star formation in NGC 1569
Battaner, E.; Relaño, M.; Lisenfeld, U. +1 more
We investigate the spatial distribution of the intrinsic extinction in the starburst dwarf galaxy NGC 1569 using an extinction map of the whole galaxy derived from the mbox H α/ mbox H β emission line ratio. We differentiate the extinction in the H ii regions from the extinction of the diffuse gas. The intrinsic extinction shows considerable varia…
Spectral shape of the UV ionizing background and O VI absorbers at z ∼ 1.5 towards HS 0747+4259
Reimers, D.; Hagen, H. -J.; Lopez, S. +5 more
Aims.We report on high resolution spectra of the bright QSO
INTEGRAL high energy behaviour of 4U 1812-12
Götz, D.; Capitanio, F.; Bird, A. J. +5 more
The low mass X-ray binary system 4U 1812-12 was monitored with the INTEGRAL observatory in the period 2003-2004 and with BeppoSAX on April 20, 2000. We report here on the spectral and temporal analysis of both persistent and burst emission. The full data set confirms the persistent nature of this burster, and reveals the presence of emission up to…
Long observations of the BALQSO LBQS 2212-1759 with XMM-Newton
Clavel, J.; Schartel, N.; Tomas, L.
Very long (172 ks effective exposure time) observations of the BALQSO
Irradiated atmospheres of accreting magnetic white dwarfs with an application to the polar AM Herculis
Gänsicke, B. T.; Beuermann, K.; König, M.
We present a pilot study of atmospheres of accreting magnetic white dwarfs irradiated by intense fluxes at ultraviolet to infrared wavelengths. The model uses a standard LTE stellar atmosphere code which is expanded by introducing an angle-dependent external radiation source. The present results are obtained for an external source with the spectra…
The non-constant slope of the C IV Baldwin effect in NGC 4151
Wang, R.; Han, J. L.; Wu, X. -B. +2 more
Context: .The relationship between the emission-line equivalent width and the continuum luminosity, called the Baldwin effect, is important for studies of the physics of the broad-line region of AGNs. Some recent studies have revealed the non-constant slope of the intrinsic Baldwin effect for several Seyfert 1 galaxies.
Aims: .Using the archiv…