Main Emission Region Research Articles

EXO 033319-2554.2: an Eclipsing AM Herculis System Showing Cyclotron Emission Features

view Abstract Citations (68) References (27) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS EXO 033319-2554.2: an Eclipsing AM Herculis System Showing Cyclotron Emission Features Ferrario, Lilia ; Wickramasinghe, D. T. ; Bailey, Jeremy ; Tuohy, I. R. ; Hough, J. H. Abstract We report spectroscopic and circular polarization observations of the soft X-ray binary EXO 033319 - 2554.2 which confirm it as a member of the AM Herculis class with properties similar to VV Puppis. Circular polarization reaching 10% in the blue and less than or equal to 2% in the I band is seen during the bright phase which lasts for 70 minutes of the 126.5 minute orbital cycle. The optical light curve exhibits a narrow eclipse due to the companion star, lasting about 8 minutes and occurring toward the end of the bright phase. The radial velocity curves show a sharp discontinuity due to an eclipse of the line-forming region by the accretion funnel and the white dwarf. Broad resolvable and variable cyclotron harmonics are seen during the bright phase. At the center of the bright phase, the emission peaks are located near 4200 Å, 5200 Å, and 6550 Å, corresponding to a magnetic field B 5.6 × 107 gauss and a temperature T = 20 keV. Detailed theoretical models suggest the presence of a second emission region of field strength B ∼ 2.8 × 107 gauss which can be seen toward the end of the bright phase. We deduce a mass ratio of ∼0.1 and estimate an orbital inclination of ∼88° and a colatitude of ∼14° for the main emission region, assuming that it is a point source and that the duration of the bright phase is Δφ ∼ 0.55. Publication: The Astrophysical Journal Pub Date: February 1989 DOI: 10.1086/167153 Bibcode: 1989ApJ...337..832F Keywords: STARS: ECLIPSING BINARIES; POLARIZATION; STARS: INDIVIDUAL ALPHANUMERIC: EXO 033319-2554.2; STARS: MAGNETIC; STARS: WHITE DWARFS; X-RAYS: BINARIES full text sources ADS | data products SIMBAD (2)

The peculiar galaxy IC 4553 - VLA-A observations of the OH megamaser

view Abstract Citations (74) References (9) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The peculiar galaxy IC 4553 : VLA-A observations of the OH megamaser. Baan, W. A. ; Haschick, A. D. Abstract VLA-A results on the OH emission in IC 4553 are presented. The data of two experiments, with low and high spectral resolutions, are discussed and are interpreted in the framework of the IC 4553 galactic structure. Attention is also given to the rotation curve, emission-line profile, and emission properties of the megamaser. The nuclear continuum source and the OH line emision source are found to be perfectly superposed, and the masing region's size is approximated at 450 pc. The OH line velocity structure is found to be most consistent with a rotating molecular disk structure centered on the continuum source. The location of the second emission region, and the rotation detected in the main emission region are covered. In addition to the disk rotation a strong Gaussian component is found in the profiles of the 1667 MHz lines. Publication: The Astrophysical Journal Pub Date: April 1984 DOI: 10.1086/161918 Bibcode: 1984ApJ...279..541B Keywords: Galactic Nuclei; Galactic Structure; Hydroxyl Emission; Interstellar Masers; Peculiar Galaxies; Radio Astronomy; Emission Spectra; Radial Velocity; Radio Interferometers; Astrophysics full text sources ADS | data products SIMBAD (1) NED (1)