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Diffraction-limited bispectrum speckle interferometry of the nuclear region of the Seyfert galaxy NGC 1068 in the H and K' bands
We present near-infrared bispectrum speckle interferometry studies ofthe nuclear region of the Seyfert 2 galaxy NGC 1068.A diffraction-limited K'-band image with 74 mas resolution and the firstH-band image with 57 mas resolution were reconstructed from speckleinterferograms obtained with the SAO 6 m telescope. The resolvedstructure consists of a compact core and an extended northern andsouth-eastern component. The compact core is resolved at all positionangles and has a north-western, tail-shaped extension as well as afainter, south-eastern extension. The K'-band FWHM diameter of thiscompact core is approximately 18 × 39 mas or 1.3 × 2.8 pc(FWHM of a single-component Gaussian fit; fit range 30-80&%slash; ofthe telescope cut-off frequency; the diameter errors are ±4 mas),and the position angle (PA) of the north-western extension is -16± 4 °. If 40% of the flux from the compact K' core isemission from a point source and 60% from a Gaussian intensitydistribution, then a slightly larger FWHM of approximately 26 × 58mas is obtained for the compact K' component. In the H band, the FWHMdiameter of the compact core is approximately 18 × 45 mas(±4 mas), and the PA is -18 ± 4 °. The extendednorthern component (PA 0 °) has an elongated structure with alength of about 400 mas or 29 pc. The extended south-eastern componentis fainter than the northern component. The K'- and H-band fluxes fromthe resolved compact core were measured to be 350 ± 90 mJy (i.e.,K' 8.2m) and 70 ± 20 mJy (H 10.4m), respectively. The PA of -16 ± 4 ° of thecompact 18 × 39 mas core is very similar to that of the westernwall (PA -15 °) of the bright region of the ionization cone.This suggests that the H- and K'-band emission from the compact core isboth thermal emission and scattered light from dust near the westernwall of a low-density, conical cavity or from the innermost region of aparsec-scale dusty torus that is heated by the central source (the dustsublimation radius of NGC 1068 is approximately 0.1-1pc). The northern extended 400 mas structure lies near the western wallof the ionization cone and coincides with the inner radio jet (PA 11 °). The large distance from the core suggests that the K'-bandemission of the northern extended component is scattered light from thewestern cavity region and the radio jet region.Based on observations made with the 6 m BTA telescope, which is operatedby the Special Astrophysical Observatory (SAO), Russia.
| The Tokyo PMC catalog 90-93: Catalog of positions of 6649 stars observed in 1990 through 1993 with Tokyo photoelectric meridian circle
The sixth annual catalog of the Tokyo Photoelectric Meridian Circle(PMC) is presented for 6649 stars which were observed at least two timesin January 1990 through March 1993. The mean positions of the starsobserved are given in the catalog at the corresponding mean epochs ofobservations of individual stars. The coordinates of the catalog arebased on the FK5 system, and referred to the equinox and equator ofJ2000.0. The mean local deviations of the observed positions from theFK5 catalog positions are constructed for the basic FK5 stars to comparewith those of the Tokyo PMC Catalog 89 and preliminary Hipparcos resultsof H30.
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משמש של הקבוצה הבאה
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תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | לויתן |
| התרוממות ימנית: | 02h47m37.69s |
| סירוב: | +00°39'59.4" |
| גודל גלוי: | 9.192 |
| תנועה נכונה: | 2.8 |
| תנועה נכונה: | -8.8 |
| B-T magnitude: | 10.653 |
| V-T magnitude: | 9.313 |
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