Search Publications
Analysis of a multi-wavelength time-resolved observation of a coronal loop
Ciaravella, A.; Reale, F.
Aims.We analyze a well-defined loop system detected in a time-resolved observation in several spectral bands to characterize the structure and evolution of coronal loops. Methods.The dataset includes simultaneous sequences of images in the 171 Å, 195 Å and 284 Å filter bands of TRACE, and in one filter of Yohkoh/SXT, with a time coverage of about …
4U 1344-60: a bright intermediate Seyfert galaxy at z = 0.012 with a relativistic Fe Kα emission line
Motch, C.; Bianchi, S.; Guainazzi, M. +6 more
We present analysis of the optical and X-ray spectra of the low Galactic latitude bright (F_2-10 = 3.6 × 10-11 erg cm-2 s-1) source 4U 1344-60. On the basis of the optical data we propose to classify 4U 1344-60 as an intermediate type Seyfert galaxy and we measure a value of z = 0.012±0.001 for its redshift. From t…
Star-forming QSO host galaxies
Barthel, P. D.
Context: .The recent finding of substantial masses of cold molecular gas as well as young stellar populations in the host galaxies of intermediate luminosity quasars is at odds with results of Hubble Space Telescope imaging studies since the latter appear to yield mature, quiescent early type hosts.
Aims: .The characterization as "quiescent" f…
The coronal Ne/O abundance of α Centauri
Liefke, C.; Schmitt, J. H. M. M.
Recent improvements in the modeling of solar convection and line formation led to downward revisions of the solar photospheric abundances of the lighter elements, which in turn led to changes in the radiative opacity of the solar interior and hence to conflicts with the solar convection zone depth as inferred from helioseismic oscillation frequenc…
Warm molecular gas in the envelope and outflow of IRAS 12496-7650 (DK Chamaeleontis)
van Dishoeck, E. F.; Schilke, P.; Güsten, R. +3 more
Aims.To obtain insight into the physical structure of the warm gas in the inner envelope of protostars and the interaction with the outflow.
Methods: .Sub-millimeter observations of 12CO, 13CO and/or C18O in J=3-2, J=4-3 and J=7-6 were obtained with the APEX Telescope towards IRAS 12496-7650, an intermediate ma…
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…