scholarly journals A spectroscopic, photometric, polarimetric, and radio study of the eclipsing polar UZ Fornacis: the first simultaneous SALT and MeerKAT observations

2020 ◽  
Vol 492 (3) ◽  
pp. 4298-4312
Author(s):  
Z N Khangale ◽  
S B Potter ◽  
P A Woudt ◽  
D A H Buckley ◽  
A N Semena ◽  
...  
Keyword(s):  
Emission Lines ◽  
Harmonic Numbers ◽  
Doppler Tomography ◽  
Secondary Star ◽  
Broad Emission ◽  
Magnetically Confined ◽  
Peak Flux ◽  
Cyclotron Emission ◽  
The Times ◽  
Inside Out

ABSTRACT We present phase-resolved spectroscopy, photometry, and circular spectropolarimetry of the eclipsing polar UZ Fornacis. Doppler tomography of the strongest emission lines using the inside-out projection revealed the presence of three emission regions: from the irradiated face of the secondary star, the ballistic stream and the threading region, and the magnetically confined accretion stream. The total intensity spectrum shows broad emission features and a continuum that rises in the blue. The circularly polarized spectrum shows the presence of three cyclotron emission harmonics at ∼4500, 6000, and 7700 Å, corresponding to harmonic numbers 4, 3, and 2, respectively. These features are dominant before the eclipse and disappear after the eclipse. The harmonics are consistent with a magnetic field strength of ∼57 MG. We also present phase-resolved circular and linear photopolarimetry to complement the spectropolarimetry around the times of eclipse. MeerKAT radio observations show a faint source that has a peak flux density of 30.7 ± 5.4 $\mu$Jy beam−1 at 1.28 GHz at the position of UZ For.

scholarly journals Simultaneous Stokes Imaging and Doppler tomography of MCVs

2004 ◽  
Vol 190 ◽  
pp. 78-84
Author(s):  
Stephen Potter ◽  
Encarni Romero-Colmenero ◽  
David Buckley ◽  
Derren Wood
Keyword(s):  
White Dwarf ◽  
Cataclysmic Variables ◽  
Doppler Tomography ◽  
Spectroscopic Observations ◽  
Secondary Star ◽  
Magnetically Confined ◽  
Magnetic Cataclysmic Variables

AbstractStokes imaging uses polarimetric observations in order to image indirectly the accretion region on the surface of the white dwarf in magnetic cataclysmic variables (MCVs). Doppler tomography uses spectroscopic observations in order to gain insights into the velocity dynamics of the secondary star, and the ballistic and magnetically confined parts of the accretion stream. Until now, both of these techniques have been applied separately. We present and compare the results of applying both techniques to simultaneous spectroscopic and polarimetric observations of MCVs.

Phase-resolved Spectroscopy and Photometry of the Eclipsing Polar UZ Fornacis

2017 ◽  
Vol 14 (S339) ◽  
pp. 314-317
Author(s):  
Z. N. Khangale ◽  
S. B. Potter ◽  
P. A. Woudt
Keyword(s):  
Doppler Tomography ◽  
Strong Emission ◽  
Secondary Star ◽  
Magnetically Confined ◽  
Balmer Lines

AbstractThe blue continuum of the eclipsing polar UZ For is dominated by single- or double-peaked emission from He ii, He i and the Balmer lines. The red spectrum shows weak emission from the Na i doublet at λ 8183 and 8194 Å and strong emission from the Ca ii lines at λ 8498 and 8542 Å. Doppler tomography of the strongest emission features reveals the presence of emission from the irradiated face of the secondary star, the threading region, and the ballistic and magnetically confined accretion stream. We have obtained 28 new eclipse times of UZ For during 2011–2016 as part of our eclipse timing follow-up programme to test the two-planet model proposed to explain variations in the eclipse times of UZ For.

scholarly journals Measuring the supermassive black hole parameters with space missions

2006 ◽  
Vol 2 (S238) ◽  
pp. 475-476
Author(s):  
Alexander F. Zakharov
Keyword(s):  
Black Hole ◽  
Spectral Line ◽  
Accretion Disks ◽  
Seyfert Galaxies ◽  
Emission Lines ◽  
X Ray ◽  
Line Shapes ◽  
Supermassive Black Hole ◽  
Broad Emission ◽  
Different Types

AbstractRecent X-ray observations of microquasars and Seyfert galaxies reveal broad emission lines in their spectra, which can arise in the innermost parts of accretion disks. Recently Müller & Camenzind (2004) classified different types of spectral line shapes and described their origin. Zakharov (2006b) clarified their conclusions about an origin of doubled peaked and double horned line shapes in the framework of a radiating annulus model and discussed s possibility to evaluate black hole parameters analyzing spectral line shapes.

scholarly journals The broad line region of AGN: Kinematics and physics

2006 ◽  
pp. 1-11 ◽  
Author(s):  
L.C. Popovic
Keyword(s):  
Electron Temperature ◽  
Accretion Disk ◽  
Emission Lines ◽  
Physical Parameters ◽  
Broad Line ◽  
Physical Conditions ◽  
Broad Line Region ◽  
Broad Emission ◽  
Line Region

In this paper a discussion of kinematics and physics of the Broad Line Region (BLR) is given. The possible physical conditions in the BLR and problems in determination of the physical parameters (electron temperature and density) are considered. Moreover, one analyses the geometry of the BLR and the probability that (at least) a fraction of the radiation in the Broad Emission Lines (BELs) originates from a relativistic accretion disk.

scholarly journals Modeling Line Emission from Disk Winds

2009 ◽  
Vol 5 (S267) ◽  
pp. 398-398
Author(s):  
Patrick B. Hall ◽  
Laura S. Chajet
Keyword(s):  
Emission Line ◽  
Accretion Disk ◽  
Line Emission ◽  
Emission Lines ◽  
Broad Emission

Murray & Chiang (1997) developed a model wherein broad emission lines come from the optically thick base of a rotating, outwardly accelerating wind at the surface of an accretion disk. Photons preferentially escape radially in such a wind, explaining why broad emission lines are usually single-peaked. Less well understood are the observed shifts of emission-line peaks (from 1000 km s−1 redshifted to 2500 km s−1 blueshifted in C iv, with an average 800 km s−1 blueshift).

A Study of the Seyfert Galaxy NGC 4151

1967 ◽  
Vol 1 (1) ◽  
pp. 7-7 ◽  
Author(s):  
J. B. Oke ◽  
Wallace L. W. Sargent
Keyword(s):  
Continuous Spectrum ◽  
Seyfert Galaxy ◽  
Seyfert Galaxies ◽  
Radio Galaxies ◽  
Emission Lines ◽  
Ngc 4151 ◽  
Broad Emission ◽  
Ngc 1068 ◽  
Stellar Sources ◽  
No Absorption

The small group of known Seyfert galaxies (Seyfert 1943) is of interest because it is clear that some violent activity is occurring in the nucleus, and some of the properties suggest a relationship with quasi-stellar sources. The spectrum of a Seyfert galaxy consists of strong, often very broad, emission lines superposed on a continuous spectrum which in some cases shows no absorption-line features. Two of the galaxies, NGC 1068 and 1275, are radio galaxies and the latter is known to be variable at radio frequencies (Dent 1966).

scholarly journals Testing the relativistic Doppler boost hypothesis for supermassive binary black holes candidates via broad emission line profiles

2019 ◽  
Vol 491 (3) ◽  
pp. 4023-4030 ◽  
Author(s):  
Zihao Song ◽  
Junqiang Ge ◽  
Youjun Lu ◽  
Xiang Ji
Keyword(s):  
Black Holes ◽  
Emission Lines ◽  
Binary Black Holes ◽  
Broad Emission ◽  
Line Region ◽  
Two Samples ◽  
Region Model ◽  
Orbital Orientation ◽  
The Continuum

ABSTRACT Optical periodicity QSOs found by transient surveys are suggested to be subparsec supermassive binary black holes (BBHs). An intriguing interpretation for the periodicity of some of those QSOs is that the continuum is radiated from the accretion disc associated with the BBH secondary component and modulated by the periodical rotation of the secondary via Doppler-boost effect. Close to edge-on orbital orientation can lead to more significant Doppler-boost effect and thus are preferred for these systems, which is distinct from those normal type-1 QSOs with more or less face-on orientations. Therefore, the profiles of broad lines emitted from these Doppler-modulated systems may be significantly different from other systems that are not Doppler modulated. We investigate the properties of the broad emission lines of optical-periodicity QSOs, including both a sample of QSOs that can be interpreted by the Doppler-modulated effects and a sample that cannot. We find that there is no obvious difference in the profiles and other properties of various (stacked) broad emission lines of these two samples, though a simple broad line region model would suggest significant differences. Our finding raises a challenge to the Doppler boost hypothesis for some of those BBHs candidates with optical periodicity.

scholarly journals Variability of NGC 3783: First Results from an Intensive Ground-Based Monitoring Campaign

1994 ◽  
Vol 159 ◽  
pp. 407-407
Author(s):  
Giovanna M. Stirpe
Keyword(s):  
Emission Lines ◽  
Intensive Monitoring ◽  
Monitoring Campaign ◽  
Broad Emission ◽  
Photometric Observations ◽  
First Results ◽  
The Continuum

The International AGN Watch collaboration undertook an intensive monitoring campaign of the bright Seyfert 1 galaxy NGC 3783 between December 1991 and August 1992, in order to study the variations of the continuum and broad emission lines. Spectroscopic and photometric observations took place at several ground-based observatories and formed the optical/IR counterpart to the UV observations conducted with the IUE (Reichert et al. 1993).

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