Садржај
Слике
Уплоадјуј своје слике
DSS Images Other Images
Везани чланци
Interstellar polarization and the position-angle orientations of type 1 Seyfert galaxies
We comment on recent spectropolarimetric studies that compare theobserved polarization position angles (PAs) of type 1 Seyfert galaxiesnear Hα with the observed orientations of their radio-source axeson the sky. For a Seyfert galaxy in which scattering occurs mainly in anequatorial scattering region, the polarization PA is expected to beparallel to the radio axis, while for a case in which light scatterspredominantly in the polar regions, the Hα polarization PA shouldbe perpendicular to the radio axis. In practice, these correlations aredifficult to establish because a Galactic interstellar polarizationcontribution can introduce a significant uncertainty into thepolarization PA determination, even when the magnitude of interstellarpolarization is small. We show how such uncertainties may affect theanalysis of PA alignments, and present spectropolarimetric observationsof a probe star along the line of sight to the type 1 Seyfert galaxy Mrk871 that allow us to assess the intrinsic Hα polarization and PAof Mrk 871. These results suggest that spectropolarimetric observationsof such probe stars should form an integral part of future polarizationstudies of Seyfert galaxies.
| Vitesses radiales. Catalogue WEB: Wilson Evans Batten. Subtittle: Radial velocities: The Wilson-Evans-Batten catalogue.
We give a common version of the two catalogues of Mean Radial Velocitiesby Wilson (1963) and Evans (1978) to which we have added the catalogueof spectroscopic binary systems (Batten et al. 1989). For each star,when possible, we give: 1) an acronym to enter SIMBAD (Set ofIdentifications Measurements and Bibliography for Astronomical Data) ofthe CDS (Centre de Donnees Astronomiques de Strasbourg). 2) the numberHIC of the HIPPARCOS catalogue (Turon 1992). 3) the CCDM number(Catalogue des Composantes des etoiles Doubles et Multiples) byDommanget & Nys (1994). For the cluster stars, a precise study hasbeen done, on the identificator numbers. Numerous remarks point out theproblems we have had to deal with.
| A preliminary compilation of DS-programme star positions
A catalog is presented of the double-star-program (DS-program) starpositions, listing right ascensions for 930 DSs and declinations for1225 DSs of the program. The positions were compiled from the observedvalues obtained between 1980 and 1987 with the meridian circles of sixUSSR observatories (the Moscow, Kazan', Kiev, Khar'kov, Odessa, andTashkent Observatories) and the Belgrade Observatory. The measurementsand the treatment of the observational material were performed using therelative method, and the FK-4 system stars were used as reference stars.
| A second list of wide visual binaries
Not Available
| A second list of wide visual binaries
Not Available
|
Додај нови чланак
Линкови у сродству са темом
Додај нови линк
Чланови следећих група \:
|
Посматрања и Астрометриски подаци
| Сазвежђа: | Херкулес |
| Ректацензија: | 16h12m07.05s |
| Deклинација: | +11°54'39.2" |
| Apparent магнитуда: | 8.461 |
| Даљина: | 225.734 parsecs |
| Proper motion RA: | 27.9 |
| Proper motion Dec: | -21.1 |
| B-T magnitude: | 8.787 |
| V-T magnitude: | 8.488 |
Каталог и designations:
|
