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The linear polarization of the optical counterpart of the transient X-ray source A0620-00 is interstellar in magnitude, position angle, and wavelength dependence. The magnitude of the polarization is consistent with a distance greater than 1 kpc.
LANDSAT imagery of the region were studied allowing the placement of the area of study in the regional geological context. A geological mapping of the 1.60.000 scale was done. A methodology was developed which consisted in a regional temperature mapping using trend surface analysis. Through the correlation of all these data, four different areas were localized with a high potential as thermomineral sources.
There are no author-identified significant results in this report.
There are no author-identified significant results in this report.
Calculations of the anisotropy of line emission from photoionized clouds, and the resulting asymmetry in the line profiles are discussed. The permitted emission-line profiles of Seyfert galaxies and QSO's often contain more light in the red than in the violet wing, and this asymmetry can arise from self-absorption of the line radiation in an expanding system of optically thick clouds. It is shown that the Balmer line optical depths are large enough to give strongly asymmetric line profiles for pure expansion, but the observed lack of strong asymmetry in the Balmer lines of most Seyfert galaxies suggests that the broad-line widths may result from random motions, or that clouds radiate isotropically. It is concluded that the frequently observed absorption of the violet wing of Lyman-alpha must occur in a surrounding region undergoing systematic outflow, or that the weakness of the Balmer line asymmetries is explained by the Balmer line emission resulting from collisional excitation from n=2.
Thirty-four spectra of DQ Her are analyzed which were obtained with a time resolution greater than 0.01 cycle. It is found that: (1) the 18th mag visual companion of DQ Her has an energy distribution similar to that of a late F star and is not likely to be a member of the system; (2) the time of minimum has no wavelength dependence and agrees better with the elements of Patterson et al. (1978) than with a linear ephemeris; (3) only very weak evidence exists for the detection of a late-type star, which is of spectral type M4 or later, even at mideclipse; (4) the spectrum of the residual light at mideclipse can be represented by optically thin free-free plus bound-free emission at a temperature of 35,000 K, an electron density of (1-10) trillion per cu cm, and a star contributing about 90% of the red flux; and (5) there is a definite asymmetry in the light curve, as well as strong evidence for a localized bright spot on the side of the disk eclipsed last.
IUE spectra of AY Lyr obtained shortly after supermaximum and normal maximum and of RX And after normal maximum are compared. All spectra are compatible with steady state disk models in the ultraviolet while the declining stages show an upturn in flux longward of 2500 A which indicates the presence of a cool component. For the same optical magnitude, the ultraviolet flux of AY Lyr is a factor of two higher after supermaximum than normal maximum, implying a larger accretion rate during supermaximum. The lines of RX And exhibit P Cyg profiles which diminish during the decline. The terminal velocities right after maximum are greater than the escape velocity but then decrease rapidly along with the column density by the third day after maximum light has ended.
The high energy emissions from cataclysmic variables (interacting binary systems containing an accreting white dwarf) and the relationship of the high energy emission of these stars to their optical properties were investigated. The relationship of the cataclysmic binaries to the strong X-ray emitting binaries that contain a neutron star as the accreting star was examined. A soft X-ray survey of cataclysmic variable stars was carried out. Approximately 75% of all the sources observed were detected in short (2000 sec) observations. Relationships between the X-ray and optical luminosity and the dependence of this quantity on the subclass of the variable were investigated and constraints on the nature of these systems were provided.
The detection of 4.75 GHz radio emissions from a white dwarf star in SU UMa is reported, and the source of the emission is discussed. The emission was discovered during a survey of six dwarf stars with a double horn receiver system. SU UMa was successfully scanned 123 times, with each scan comprising 31 3-sec integrations 30 arcsec apart. Average fluxes for each beam position were calculated, as was the X ray emission of 7.6 x 10 to the 54th/cu cm in the 0.1-4.5 keV band. The small mass outflow projected for the object indicates a source of suprathermal electrons for the radio emissions A cyclotron maser instability is suggested as the mechanism, and future measurements to detect circular polarization as proof of a coherent source are indicated.
One series of data comprising the present J, H, K broadband IR photometry of the cataclysmic binary system U Geminorum over the course of two orbital cycles was obtained several days before an outburst, while a second was gathered when the system had almost completely returned to quiescence from that outburst. In quiescence, the M4-M5.5 red dwarf star supplies most of the IR luminosity of the system, while the light curves at this time are tidally induced ellipsoidal variations of the red dwarf which exhibit an amplitude such that the red dwarf must fill, or nearly fill, its Roche lobe. This shows directly that Roche lobe overflow is important in cataclysmic variable stars. The range of the disk IR colors after outbursts suggest that cool and optically thick gas, together with optically thin gas, supply most of the IR light of the disk.
A series of low-dispersion spectra and one high-dispersion spectrum have been obtained of the catacylsmic variable CPD-48 deg 1577. Like other UX UMa stars, this variable exhibits the flat continuum of a luminous, thick, steady state accretion disk dominating its light from the far UV to the infrared. A wind mass loss rate of less than about 10 to the -9th solar mass/yr and an accretion rate of roughly 5 x 10 to the -9th solar mass/yr is roughly consistent with the range which characterizes other UX UMa stars. An SWP echelle spectrum reveals detailed line profile information on the N V, Si IV, and C IV resonance lines. He II 1640 A is remarkably weak and even absent in two of the spectra. The known properties and evolutionary status of CPD-48 deg 1577 and the other UX UMa stars are summarized.
Far-ultraviolet observations of a burst of SS Cyg obtained with the Voyager spacecraft are presented along with optical observations. Representative V band and far-UV light curves are computed based on a thermal instability model, and the dependence of the far-UV delay and the shape of the outburst on the location in the disk where the outburst starts is examined. The results show that burst initiated at large radii produce asymmetric light curves for which the far-UV flux lags the optical flux by about half a day, as observed. For bursts starting at smaller radii, the delay is smaller and the outburst is more rounded and symmetric. For both burst types, the delay with respect to the optical is longer for larger accretion disks and at shorter wavelengths. The physical processes that will promote burst initiation in the outer disk are discussed, emphasizing that this can occur in principle with no modulation of the mass transfer rate from the companion.
A search for accretion of wind-flare material onto the white dwarf in V471 Tauri has unexpected by revealed what appears to be shortward-shifted absorption, centered on two distinct velocities, near heliocentric velocities of -300 and -590 km/s in the line of sight toward V471 Tauri. The possibility that these features are due to instrumental effects is explored. The narrow interstellar-like appearance of the -590 km/s component and lack of variability with orbital phase indicate that the observed high-velocity absorption components are formed at a great distance from the V471 Tauri system and probably owe their origins to a discrete mass ejection event.
Time-resolved X-ray and optical photometric and optical spectroscopic observations of the ultrashort period cataclysmic variable SW UMa are reported. The spectroscopic observations reveal the presence of an s-wave component which is almost in phase with the extreme line wings and presumably the white dwarf. This very unusual phasing in conjunction with the available optical and X-ray data seems to indicate that a region of enhanced emission exists on the opposite side of the disk from the expected location of the hot spot. The photometric observations reveal the presence of a hump in the light curve occurring at an orbital phase which is consistent with the phase at which the region of enhanced line emission is most favorably seen. Changes in the hump amplitude are seen from night to night, and a 15.9 min periodicity is evident in the light curve. The optical and X-ray periodicities suggest that SW UMa is a member of the DQ Her class of cataclysmic variables.
IUE observations in the 1150-3250-A region were obtained of GK Per during the rise, at the maximum, and during the decline of the 2.5-mag optical outburst in 1981. The results support previous predictions for the interaction of an accretion disk with the magnetic field of an accretion star. The luminosity at minimum is found to be 2.3 solar luminosities, with 1/3 of this being attributed to the cool secondary star.
Spectroscopic observations of V1819 Cyg, V827 Her, and V2214 Oph, obtained at 1-2.5 microns using a 32-channel InSb array detector at the Cassegrain focus of the 2.7-m telescope at McDonald Observatory during 1986-1989, are reported. The data are presented in extensive tables and graphs and characterized in detail, with a focus on the nature of the 'coronal' emission. The ratios of Br-gamma (2.167 microns) and forbidden Si VI (1.960 microns) are found to be consistent with coronal gas temperatures of about 10,000 K and with photoionization as the primary mechanism of origin for the coronal species. Severe constraints on theoretical models involving shock heating and collisional ionization are inferred.
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