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The origin of the anomalous intensity ratio between very bright UV FeII lines and their satellites in gaseous condensations close to the star eta Carinae
Johansson, S.; Letokhov, V. S.; Klimov, V.
We present a model that explains the anomalous intensity ratios between each of two very bright UV lines of Fe II at 2507 Å and 2509 Å and its corresponding satellite line, observed in HST spectra of a compact gaseous condensation (blob B) in the vicinity of the star protect eta Car.The model is based on the assumption that the FeII transitions ha…
An unusual iron Lo-BAL quasar detected by ISOCAM
Elbaz, D.; Cesarsky, C.; Duc, P. -A. +10 more
We report the discovery of an unusual low-ionization broad absorption line quasar at z=1.776 which exhibits absorption lines from many excited states of Fe II. This member of the rare class of ``FeLoBAL'' quasars was serendipitously found in a mid-infrared (MIR) survey of distant clusters carried out with the ISOCAM camera. ISO J005645.1-273816 ha…
Star formation in the warped outer pseudoring of the spiral galaxy NGC 3642
Bosma, A.; Athanassoula, E.; Verdes-Montenegro, L.
NGC 3642 was classified as a spiral galaxy with three rings and no bar. We have performed an HI and optical study of this nearly face-on galaxy. We find that the nuclear ring might in fact be part of an inner one-armed spiral, that could be driving nuclear accretion and feeding the central activity in the inner kpc. The inner ring is faint, and th…
Detectability and characteristics of the 2.223 MeV line emission from nearby X-ray binaries
Guessoum, N.; Jean, P.
We present an application and an improvement of the model of Jean & Guessoum (\cite{JG01}) for the production of the 2.223 MeV line resulting from the capture of neutrons in the atmosphere of the secondary in an X-ray binary system. In this model, the neutrons are produced in the accretion disk around the compact primary star and radiated in a…
Solar system objects in the ISOPHOT 170 mu m serendipity survey
Müller, T. G.; Stickel, M.; Hotzel, S.
The ISOPHOT Serendipity Survey (ISOSS) covered approximately 15% of the sky at a wavelength of 170 mu m while the ISO satellite was slewing from one target to the next. By chance, ISOSS slews went over many solar system objects (SSOs). We identified the comets, asteroids and planets in the slews through a fast and effective search procedure based …
Distances of absorbing features in the LDN 1622 direction. An application of Tycho-2 photometry and Michigan Classification
Fabricius, C.; Makarov, V.; Knude, J. +1 more
With Tycho-2 BT and VT photometry of Hipparcos stars with π > 8.0 mas, σπ/π < 15% and with spectral type and luminosity classification from the Michigan Catalogues we have a presumably unreddened sample for establishing a (BT-VT_0- MV_T main sequence relation in the range from…
Detection of new optical counterpart candidates to PSR B1951+32 with HST/WFPC2
Golden, A.; Shearer, A.; Butler, R. F.
There remain several definitive gamma -ray pulsars that are as yet undetected in the optical regime. A classic case is the pulsar PSR B1951+32, associated with the complex CTB 80 SNR. Previous ground based high speed 2-d optical studies have ruled out candidates to mV ~ 24. Hester (2000a) has reported an analysis of archival HST/WFPC2 o…
What is the real nature of blinkers?
Erdélyi, R.; Marik, D.
In the present paper a simple physical model of blinkers based on the process of magnetic reconnection is developed. Blinkers were first found in transition region lines (e.g. He I, O III, O IV, O V and Mg IX) by SOHO CDS. Their typical lifetime is approximately 16 min, the intensity enhancement ratios are around 1.8, and they appear at 1-20 s
XMM-Newton observation of the BAL Quasar PHL 5200:. The big surprise
Brinkmann, W.; Gliozzi, M.; Ferrero, E.
XMM-Newton observations of the BAL quasar PHL 5200 revealed that the X-ray emission attributed to the quasar originates from a nearby, optically unidentified radio source. Although visible in X-rays as well the flux from PHL 5200 is by a factor ga 20 smaller than previously anticipated. Thus most of the scenarios for a physical interpretation of t…
Filling factors and magnetic field strengths of nanoflare-heated coronal active regions: Yohkoh and MDI observations
Yashiro, S.; Jain, R.
The scaling laws describing the relationship between thermal and magnetic properties of active regions are derived using the concept that solar coronal active regions are heated by numerous small flare-like events (nanoflares). Thus, a coronal active region is viewed as an ensemble of hot elementary filaments created within the coronal magnetic fi…