Search Publications
XMM-Newton observations of the isolated neutron star 1RXS J214303.7+065419/RBS1774
Cropper, Mark; Turolla, Roberto; Zampieri, Luca +4 more
We report XMM-Newton observations of the isolated neutron star RBS1774 and confirm its membership as an XDINS. The X-ray spectrum is best fit with an absorbed blackbody with temperature kT=101 eV and absorption edge at 0.7 keV. No power law component is required. An absorption feature in the RGS data at 0.4 keV is not evident in the EPIC data, but…
Filamentary Structures of Coronal White-Light Images
Woo, Richard
In the absence of magnetic field measurements of the solar corona, the density structure of white-light images has provided important insight into the coronal magnetic field. Recent work sparked by highly sensitive radio occultation measurements of path-integrated density has elucidated the density structure of unprocessed solar eclipse pictures. …
Optical astrometric positions of 59 northern ICRF radio sources
Assafin, M.; Camargo, J. I. B.; Andrei, A. H. +5 more
Context: To investigate the link between the International Celestial Reference Frame (ICRF) and its optical Hipparcos-based representation on the northern hemisphere.
Aims: To present results of a pilot investigation on the astrometry of 59 northern ICRF sources.
Methods: We used the 0.6 m Zeiss telescope at Belogradchik Observatory, Bulga…
High-mass X-ray binaries and the spiral structure of the host galaxy
Gilfanov, M. R.; Shtykovskiy, P. E.
We investigate the manifestation of the spiral structure in the distribution of high-mass X-ray binaries (HMXBs) over the host galaxy. We construct the simplest kinematic model. It shows that the HMXBs should be displaced relative to the spiral structure observed in such traditional star formation rate indicators as the Hα and far-infrared emissio…
Imaging the Dust Trail and Neckline of 67P/Churyumov-Gerasimenko
Agarwal, Jessica; Boehnhardt, Hermann; Gruen, Eberhard
We report on the results of nearly 10 hours of integration of the dust trail and neckline of comet 67P/Churyumov- Gerasimenko (67P henceforth) using the Wide Field Imager at the ESO/MPG 2.2m telescope in La Silla. The data was obtained in April 2004 when the comet was at a heliocentric distance of 4.7 AU outbound. 67P is the target of the Rosetta …
Detection of Martian dust clouds by SPICAM UV nadir measurements during the October 2005 regional dust storm
Montmessin, F.; Bertaux, J. L.; Fussen, D. +5 more
The SPICAM UV spectrometer onboard Mars Express observed two regional dust storms: on October 24, 2005, near Argyre Planitia and on July 9, 2005, in Hellas Planitia. The measurements were performed in nadir mode. The spectral domain 210-310 nm is considered. A comparison with a prior orbit which passed above almost the same path 6 days before the …
Radio Continuum Sources Associated with AB Aur
Rodríguez, L. F.; Ho, P. T. P.; Zapata, L.
We present high angular resolution, high-sensitivity Very Large Array observations at 3.6 cm of the Herbig Ae star AB Aur. This star is of interest since its circumstellar disk exhibits characteristics that have been attributed to the presence of an undetected low mass companion or giant gas planet. Our image confirms the continuum emission known …
Far-Infrared Detection of H2D+ toward Sgr B2
Cernicharo, J.; Goicoechea, J. R.; Polehampton, E.
We report on the first far-IR detection of H2D+, using the Infrared Space Observatory, in the line of sight toward Sgr B2 in the Galactic center. The transition at λ=126.853 µm connecting the ground level of o-H2D+, 11,1, with the 21,2 level at 113 K is observed in absorption …
Modeling Minor Ion Abundances in Quiescent Coronal Loops
Lie-Svendsen, Øystein; Killie, Mari Anne
We model minor element abundances in quiescent coronal loops anchored in the chromosphere, solving transport equations that give an improved description of thermal forces. Ionization, recombination, and radiative loss are included. The plasma consists of hydrogen and a minor element (oxygen, silicon, or iron), and we solve for all relevant charge …
Light Superconducting Strings in the Galaxy
Ferrer, Francesc; Vachaspati, Tanmay
Observations of the Milky Way by the SPI/INTEGRAL satellite have confirmed the presence of a strong 511 keV gamma ray line emission from the bulge, which requires an intense source of positrons in the galactic center. These observations are hard to account for by conventional astrophysical scenarios, whereas other proposals, such as light DM, face…