Search Publications
INTEGRAL observations of the variability of OAO 1657-415
Klochkov, D.; Santangelo, A.; Wilms, J. +7 more
Context: The Galactic Plane Scan (GPS) was one of the core observation programmes of the INTEGRAL satellite. The highly variable accreting pulsar
Aims: We investigate the spectral and timing properties of OAO 1657-415 and their variability on short and long time scales in …
X-ray spectral variability in PG 1535+547: the changing look of a ``soft X-ray weak'' AGN
Cappi, M.; Vignali, C.; Schartel, N. +5 more
Context:
Origin of chromatic features in multiple quasars. Variability, dust, or microlensing
Yonehara, A.; Richter, P.; Hirashita, H.
Aims:In some of lensed quasars, color differences between multiple images are observed at optical/near-infrared wavelengths. There are three possible origins for the color differences: intrinsic variabilities of quasars, differential dust extinction, and quasar microlensing. We examine how these possible scenarios can reproduce the observed chroma…
Sizes of transition-region structures in coronal holes and in the quiet Sun
Tu, C. -Y.; Marsch, E.; Tian, H. +2 more
Aims: We study the height variations of the sizes of chromospheric and transition-region features in a small coronal hole and the adjacent quiet Sun, considering images of the intensity, Doppler shift, and non-thermal motion of ultraviolet emission lines as measured by SUMER (Solar Ultraviolet Measurements by Emitted Radiation), together with the …
Evidence of a type 1/type 2 dichotomy in the correlation between quasar optical polarization and host-galaxy/extended emission position angles
Magain, P.; Hutsemékers, D.; Borguet, B. +2 more
Aims:For Seyfert galaxies, the AGN unification model provides a simple and well-established explanation of the type 1/type 2 dichotomy through orientation-based effects. The generalization of this unification model to the higher luminosity AGNs that quasars are remains a key question. The recent detection of type 2 radio-quiet quasars seems to sup…
Spitzer Space Telescope observations of the nucleus of comet 67P/Churyumov-Gerasimenko
Jorda, L.; Lamy, P. L.; Groussin, O. +3 more
Context: Comet 67P/Churyumov-Gerasimenko is the target of the Rosetta mission, and an early characterization of its nucleus is required to assist in preparing the orbital strategy of the spacecraft, the delivery of the Philae surface module and the science operations. We detected the nucleus using the Hubble Space Telescope in March 2003, but had …
Hen 2-104: a close-up look at the Southern Crab
Morisset, C.; Schirmer, M.; Balick, B. +5 more
Aims: The kinematics, shaping, density distribution, expansion distance, and ionized mass of the nebula Hen 2-104, and the nature of its symbiotic Mira are investigated.
Methods: A combination of multi-epoch HST images and VLT integral field high-resolution spectroscopy is used to study the nebular dynamics both along the line of sight and in …
An X-ray view of absorbed INTEGRAL AGN
de Rosa, A.; Walter, R.; Ubertini, P. +4 more
Aims: We present a 0.2-200 keV broadband study of absorbed Active Galactic Nuclei (AGN) observed with INTEGRAL, XMM-Newton, Chandra, and ASCA to investigate the continuum shape and the absorbing/reflecting medium properties.
Methods: The sources are selected in the INTEGRAL AGN sample to have a 20-100 keV flux below 8× 10-11 erg cm<…
Comet 67P/Churyumov-Gerasimenko at a large heliocentric distance
Tubiana, C.; Boehnhardt, H.; Drahus, M. +1 more
Aims: The Jupiter family comet 67P/Churyumov-Gerasimenko (67P/C-G) is the target comet of ESA's ROSETTA mission. A detailed portrait of this comet has been drawn from observations around perihelion, but what needs to be enhanced is the description of the comet's behaviour at large heliocentric distance. It is not only important for planning the re…
XMM-Newton X-ray spectra of the SNR 0509-67.5: data and models
Vink, J.; Kosenko, D.; Blinnikov, S. +1 more
Aims: We report on X-ray observations of the supernova remnant 0509-67.5 in the Large Magellanic Cloud acquired by the XMM-Newton X-ray observatory. We use the imaging spectroscopy (EPIC) and Reflective Grating Spectrometer (RGS) data to investigate properties of the remnant and its environment.
Methods: The X-ray spectra were analyzed with SP…