Search Publications
The 26 year-long X-ray light curve and the X-ray spectrum of the BL Lacertae object 1E 1207.9+3945 in its brightest state
Tramacere, A.; Giommi, P.; Maselli, A. +4 more
Aims:We studied the temporal and spectral evolution of the synchrotron emission from the high energy peaked BL Lac object 1E 1207.9+3945.
Methods: Two recent observations have been performed by the XMM-Newton and Swift satellites; we carried out X-ray spectral analysis for both of them, and photometry in optical-ultraviolet filters for the Swi…
Small-scale flows in SUMER and TRACE high-cadence co-observations
Doyle, J. G.; Madjarska, M. S.
Context: We report on the physical properties of small-scale transient flows observed simultaneously at high cadence with the SUMER spectrometer and the TRACE imager in the plage area of an active region.
Aims: Our major objective is to provide a better understanding of the nature of transient phenomena in the solar atmosphere by using high-ca…
On the ultraviolet signatures of small scale heating in coronal loops
Young, P. R.; Parenti, S.
Aims: Studying the statistical properties of solar ultraviolet emission lines could provide information about the nature of small scale coronal heating. We expand on previous work to investigate these properties. We study whether the predicted statistical distribution of ion emission line intensities produced by a specified heating function is aff…
EROs found behind lensing clusters. II. Empirical properties, classification, and SED modelling based on multi-wavelength observations
Kneib, J. -P.; Schaerer, D.; Pelló, R. +5 more
Aims:We study the properties and nature of extremely red galaxies (ERO, R-K≥5.6) found behind two lensing clusters and compare them with other known galaxy populations.
Methods: New HST/ACS, Spitzer (IRAC and MIPS), and Chandra/ACIS observations of the two lensing clusters Abell 1835 and AC114 have been obtained, combined with our earlier opti…
Spatial distribution of dust in the shell elliptical NGC 5982
Del Burgo, C.; Carter, D.; Sikkema, G.
Aims:Shells in Ellipticals are peculiar faint sharp edged features that are thought to be formed by galaxy mergers. We determine the shell and dust distributions, and colours of a well-resolved shell and the underlying galaxy in NGC 5982, and compare the spatial distributions of the dust and gas phases, in order to investigate the origin of shells…
Near-infrared polarization images of the Orion proplyds
Eckart, A.; Ott, T.; Rost, S.
Aims: The aim is to study structure and polarization properties of the stars and planet systems in the active Orion H II-region.
Methods: We performed AO-assisted high-resolution imaging polarimetry on selected Orion proplyds close to the Trapezium stars in the J, H, and K bands. Differential polarimetric images of one of the largest and brigh…
Low heat conduction in white dwarf boundary layers?
Burwitz, V.; Liu, F. K.; Meyer, F. +1 more
Context: X-ray spectra of dwarf novae in quiescence observed by Chandra and XMM-Newton provide new information on the boundary layers of their accreting white dwarfs.
Aims: Comparison of observations and models allows us to extract estimates for the thermal conductivity in the accretion layer and reach conclusions on the relevant physical proc…
A mid-infrared study of H II regions in the Magellanic Clouds: N88 A and N160 A
Tielens, A. G. G. M.; Peeters, E.; Martín-Hernández, N. L.
Aims: To show the importance of high-spatial resolution observations of H II regions when compared with observations obtained with larger apertures such as ISO, we present mid-infrared spectra of two Magellanic Cloud H II regions, N88 A and N160 A.
Methods: We obtained mid-infrared (8-13 µm), long-slit spectra with TIMMI2 on the ESO 3.6 …
Discovery, photometry, and astrometry of 49 classical nova candidates in M 81 galaxy
Garnavich, P. M.; Thilker, D. A.; Hornoch, K. +2 more
Aims: This paper reports on a search for new classical nova candidates in the M 81 galaxy based on archival, as well as recent, new images.
Methods: We used images from 1999-2007 to search for optical transients in M 81. The positions of the identified classical nova candidates were used to study their spatial distribution. Kolmogorov-Smirnov …
EUV spectral energy distribution of quasars restored from associated absorbers
Reimers, D.; Levshakov, S. A.; Agafonova, I. I. +2 more
Aims: We reconstruct the spectral shape of the quasar ionizing radiation in the extreme-UV range (1 Ryd ≤ E < 10 Ryd) from the analysis of narrow absorption lines (NAL) of the associated systems.
Methods: The computational technique for inverse spectroscopic problems - a Monte Carlo Inversion augmented by the spectral shape recovering proce…