Search Publications
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…
Microflaring of a solar bright point
Curdt, W.; Huovelin, J.; Vilhu, O. +2 more
A 50 x 50 arcsec region near the solar disc center containing a bright point (BP) was observed with the SUMER- spectrograph of the SOHO observatory. The data consist of two hours observation of four far-UV emission lines formed between 2 x 104-6x 105 K, with 2 arcsec spatial, 2.8 min temporal and 4 km s-1 spectral …
Observing programs of the Kyiv meridian axial circle equipped with a CCD micrometer
Andruk, V.; Babenko, Yu.; Lazorenko, P. +6 more
The present status of the Kyiv meridian axial circle after its refurbishment is described. The mounting of a new micrometer with the front-illuminated CCD 1040x1160 allows to observe stars up to V=16 mag. For the stars of 11-14 mag, the internal positional accuracy of a single observation is 0.05-0.10'', and stellar V values are determined with an…
ISOPHOT far-infrared photometry of NGC 3079
Walker, H. J.; Klaas, U.
FIR photometry (from 15 mu m to 200 mu m) of NGC 3079 which is resolved by ISOPHOT at 60 mu m is presented. With the assumption of an unresolved core plus an extended disk component, good consistency with IRAS and SCUBA data is found. The SED of the total flux between 60 mu m and the submm can be modelled by the superposition of three dust compone…
UV line intensity and flow velocity distributions in two coronal mass ejections as deduced by UVCS-SOHO observations
Uzzo, M.; Spadaro, D.; Ventura, R. +1 more
The Ultraviolet Coronagraph Spectrometer (UVCS) instrument onboard the SOHO satellite observed two coronal mass ejections on November 2 and 3, 2000, related to the eruptions of a large filament structure in an active region close to the West limb of the Sun, and of a prominence near the South Pole, respectively. Intensity and profile of the O VI r…