scholarly journals A STUDY OF THE TIME VARIABILITY AND LINE PROFILE VARIATIONS OF κ DRA

2021 ◽  
Vol 57 (1) ◽  
pp. 91-105
Author(s):  
S. M. Saad ◽  
M. I. Nouh ◽  
A. Shokry ◽  
I. Zead
Keyword(s):  
Line Profile ◽  
Orbital Period ◽  
Circular Orbit ◽  
Spectroscopic Analysis ◽  
Emission Lines ◽  
Time Variability ◽  
Line Profiles ◽  
Orbital Elements ◽  
Balmer Lines ◽  
Be Star

We present a spectroscopic analysis of the bright Be star Κ Dra. Two independent sets of radial velocity (RV) measurements were obtained by direct measurement and using a line profile disentangling technique. By combining solutions from codes FOTEL and KOREL, we derived improved orbital elements. From the RVs of the Balmer lines and also from some strong metallic lines we found that all RV variations are phase-locked with the orbital period. V/R variations were obtained for Hα, Hβ, Hγ and some other photospheric lines. A moving absorption bump superposed over the emission line profiles was detected. The orbital solutions for Κ Dra were derived assuming a circular orbit with a period P = 61d.5549 and K = 6.81 km s−1. We failed to find absorption or emission lines for the unresolved secondary component.

scholarly journals Emission activity of the Be star 60 Cygni

2017 ◽  
pp. 51-57
Author(s):  
K. Sejnová ◽  
V. Votruba
Keyword(s):  
Time Evolution ◽  
Line Profile ◽  
Equivalent Width ◽  
Spectroscopic Analysis ◽  
Circumstellar Disk ◽  
Line Profiles ◽  
Emission Activity ◽  
Be Star

In this paper we present results of spectroscopic analysis of the H? line profile of the Be star 60 Cygni. We present time evolution of the equivalent width of the H? line profiles during years 1992 - 2016 and V=R variation during years 1995 - 2016. We analyzed data from Ond?ejov Observatory and from BeSS Database. The circumstellar disk of the star was present twice during years 1992 - 2016 and the second cycle shows stronger emission activity. We found out that the formation of the disk takes longer time than the disk extinction (the extinction is much steeper than the formation) and that there is no evident period of changes in the V=R variation.

scholarly journals Predicting the broad-lines polarization emitted by supermassive binary black holes

2019 ◽  
Vol 623 ◽  
pp. A56 ◽  
Author(s):  
D. Savić ◽  
F. Marin ◽  
L. Č. Popović
Keyword(s):  
Black Holes ◽  
Emission Lines ◽  
Polarization Angle ◽  
Broad Line ◽  
Line Profiles ◽  
Binary Black Holes ◽  
True Nature ◽  
Line Shapes ◽  
Highly Sensitive ◽  
Balmer Lines

Context. Some Type-1 active galactic nuclei (AGN) show extremely asymmetric Balmer lines with the broad peak redshifted or blueshifted by thousands of km s−1. These AGN may be good candidates for supermassive binary black holes (SMBBHs). The complex line shapes can be due to the complex kinematics of the two broad line regions (BLRs). Therefore other methods should be applied to confirm the SMBBHs. One of them is spectropolarimetry. Aims. We rely on numerical modeling of the polarimetry of binary black holes systems, since polarimetry is highly sensitive to geometry, in order to find the specific influence of supermassive binary black hole (SMBBH) geometry and dynamics on polarized parameters across the broad line profiles. We apply our method to SMBBHs in which both components are assumed to be AGN with distances at the subparsec scale. Methods. We used a Monte Carlo radiative transfer code that simulates the geometry, dynamics, and emission pattern of a binary system where two black holes are getting increasingly close. Each gravitational well is accompanied by its own BLR and the whole system is surrounded by an accretion flow from the distant torus. We examined the emission line deformation and predicted the associated polarization that could be observed. Results. We modeled scattering-induced broad line polarization for various BLR geometries with complex kinematics. We find that the presence of SMBBHs can produce complex polarization angle profiles φ and strongly affect the polarized and unpolarized line profiles. Depending on the phase of the SMBBH, the resulting double-peaked emission lines either show red or blue peak dominance, or both the peaks can have the same intensity. In some cases, the whole line profile appears as a single Gaussian line, hiding the true nature of the source. Conclusions. Our results suggest that future observation with the high resolution spectropolarimetry of optical broad emission lines could play an important role in detecting subparsec SMBBHs.

scholarly journals Spectrophotometry of Supernovae

1974 ◽  
Vol 3 ◽  
pp. 533-544
Author(s):  
R. P. Kirshner
Keyword(s):  
Emission Lines ◽  
Absorption Lines ◽  
Spectral Energy ◽  
Line Profiles ◽  
Energy Distributions ◽  
Maximum Light ◽  
Balmer Lines ◽  
B Lines ◽  
Infrared Triplet ◽  
The Continuum

AbstractAbsolute spectral energy distributions for supernovae of both types I and II have been obtained. These observations demonstrate three facets of supernova spectra. First, both SN I’s and SN II’s have a continuum that varies slowly and uniformly with time, and which carries the bulk of the radiated flux at early epochs. Second, some lines in both SN I’s and SN II’s have P Cygni profiles: broad emissions flanked on their violet edges by broad absorptions. Third, some lines are common to SN I’s and SN II’s and persist throughout the evolution of the spectrum. The continuum temperatures for both SN I’s and SN II’s are about 10000 K at the earliest times of observation and drop in one month’s time to about 6000 K for SN II’s and about 7000 K for SN I’s. After several months, the continuum may cease to carry the bulk of the flux, which might be in emission lines, but continues to exist, as shown by the presence of absorption lines. The P Cygni line profiles indicate expansion velocities of 15000 km s-1 in SN II’s and 20000 km s-11 in the SN I 1972e in NGC 5253. Line identifications for SN II’s include Hα, Hβ, H and K of Ca II, the Ca II infrared triplet at λ8600, the Na I D-lines, the Mg I b-lines at λ5174, and perhaps Fe II. The [O I] lines λλ6300, 6363 and [Ca II] lines λλ7291, 7323 appear after eight months. For SN I’s, the lines identified are H and K of Ca II, the infrared Ca II lines, the Na I D-lines, and the Mg I b-lines. There is some evidence that Balmer lines are present two weeks after maximum. The strong and puzzling λ4600 features drifts with time from λ4600 near maximum light to λ4750 after 400 days.

scholarly journals Semi-empirical Model of the Star V923 Aquilae

2000 ◽  
Vol 175 ◽  
pp. 547-549
Author(s):  
M. L. Arias ◽  
L. S. Cidale ◽  
A. E. Ringuelet
Keyword(s):  
Radial Velocity ◽  
Empirical Model ◽  
Orbital Period ◽  
Near Infrared ◽  
Infrared Region ◽  
Orbital Phase ◽  
Balmer Lines ◽  
Be Star ◽  
Near Infrared Region ◽  
Semi Empirical

V923 Aquilae (HD 183656) is a Be star which shows emission in Hα, cyclic V/R variations and variations in the near infrared region. This star displays a shell spectrum recognized by Harper(1937) and Bidelman (1950) who both remarked the presence of shell H lines, strong Fe II lines and variable radial velocity. Koubský et al. (1989) proposed V923 Aquilae to be a spectroscopy binary with an orbital period of 214.756 days and a semi-amplitude of 6.2 km/s. Iliev et al. (1994) found a correlation between the changes of the Balmer progression and the asymmetries of the Balmer lines with the orbital phase, considering the period calculated by Koubský.

scholarly journals Wind-wind collision effects in close massive WR+O binaries

1995 ◽  
Vol 163 ◽  
pp. 397-405
Author(s):  
S.V. Marchenko
Keyword(s):  
Ionization Potential ◽  
Orbital Period ◽  
Bow Shock ◽  
Emission Lines ◽  
Line Profiles ◽  
Emission Component ◽  
Shock Region ◽  
Orbital Phase

A detailed description of the wind-wind collision (WWC) zones in the Wolf-Rayet binaries V444 Cyg (WN5+O6III-V, P = 4.21 d) and CX Cep (WN5+O5V, P = 2.13 d) is presented. In V444 Cyg, parameters of the WWC zone can be derived from variations of HeI line profiles. There is some evidence for a highly unstable character of the WWC zone. In CX Cep, the complicated dependence of equivalent widths for emission lines of different ionization potential on orbital phase can be explained by a combination of several factors, e.g., (a) additional ionization from the bow shock region; (b) reheating of the WR wind by the O-star companion; and (c) an emission component arising in the WWC region. Some preliminary indications of WWC are revealed in the WR+OB system CQ Cep (WN7+O9I-II?) with the shortest known orbital period: P = 1.64 d.

scholarly journals Variability of the Emission-Line Spectrum of the Nucleus of the Seyfert Galaxy NGC 7469

1975 ◽  
Vol 67 ◽  
pp. 605-609
Author(s):  
I. I. Pronik
Keyword(s):  
Emission Line ◽  
Seyfert Galaxy ◽  
Emission Lines ◽  
Time Variability ◽  
Variable Time ◽  
Balmer Lines ◽  
Hα Emission ◽  
Emission Line Spectrum ◽  
Hydrogen Lines ◽  
Ngc 7469

It is shown that the emission lines of the NGC 7469 nucleus spectrum are variable. Time variability of hydrogen lines is less than 20 days. The Hα emission line is at the profile base about a factor of two narrower than the Hγ line. Estimation of the density of hydrogen envelope, where Balmer lines wings were emitted, gives the value of about 108–109 cm−3.

scholarly journals Short-period Variations of 28 CMa during 1998/9

2000 ◽  
Vol 175 ◽  
pp. 236-239
Author(s):  
L.A. Balona ◽  
D. James
Keyword(s):  
Radial Velocity ◽  
Line Profile ◽  
Periodic Variation ◽  
Emission Lines ◽  
Circumstellar Disk ◽  
Be Stars ◽  
Short Period ◽  
Metal Absorption ◽  
Period Variations ◽  
Be Star

AbstractThe Be star 28 CMa was one of the first periodic Be stars to be discovered and shows very large line profile variations with a period of 1.37 d. Recently, it has been shown that the line profile and light variations can be modeled by a patch of gas suspended above the photosphere. We present echelle observations of the Hβ and Hϒ line and several helium and metal absorption lines. We show that the radial velocity variations of these lines are unchanged since they were first observed two decades ago. We also examined several emission lines of Fe II and show that they do not partake of the periodic variation. We attribute the periodic variations of the lines formed close to the photosphere to a co-rotating cloud, whereas the Fe II emission lines are formed in the circumstellar disk outside the co-rotating radius.

scholarly journals The massive Wolf-Rayet binary WR 98 (WN7/WC+08-9)

2003 ◽  
Vol 212 ◽  
pp. 184-185 ◽  
Author(s):  
Roberto C. Gamen ◽  
Virpi S. Niemela
Keyword(s):  
Emission Line ◽  
Circular Orbit ◽  
Orbital Motion ◽  
Emission Lines ◽  
Absorption Lines ◽  
Line Spectrum ◽  
Mass Ratio ◽  
Orbital Elements ◽  
Spectroscopic Binary ◽  
Emission Line Spectrum

We present the discovery of OB type absorption lines superimposed to the emission line spectrum, and the first double-lined orbital elements, for the massive Wolf-Rayet binary WR 98 (HDE 318016, WN7/C+08-9), a spectroscopic binary in a circular orbit with a period of 47.825 d. The semi-amplitudes of the orbital motion of the emission lines differ from line to line, indicating a mass ratio in the range q ≡ MWR/MOB = 1–1.8.

scholarly journals Emission Line Variations of BLRG

1994 ◽  
Vol 159 ◽  
pp. 444-444
Author(s):  
M. Dietrich ◽  
W. Kollatschny
Keyword(s):  
Emission Line ◽  
Line Profile ◽  
Size Structure ◽  
Optical Emission ◽  
Emission Lines ◽  
Broad Line ◽  
Line Profiles ◽  
Fundamental Parameters ◽  
Broad Emission ◽  
Calar Alto

In late 1989 we started a monitoring campaign of the line profile variations of more than 40 Broad-Line Radio Galaxies (BLRG) at Calar Alto Observatory/Spain. BLRG are the most extreme species of AGN regarding line width and structure of their optical emission line profiles showing FWZI up to 35000 km s−1, eg. 3C332 or Arp102B. Quite often the broad emission line profiles are characterized by a double hump structure. The analysis of the broad emission lines provides information about fundamental parameters of the inner part of the AGN like size, structure and kinematics of the line emitting region. In the following we present line profile variations of a BLRG we are studying.

scholarly journals Line Profile Modeling of Disks

2000 ◽  
Vol 175 ◽  
pp. 396-408 ◽  
Author(s):  
W. Hummel
Keyword(s):  
Line Profile ◽  
Spectral Lines ◽  
Three Dimensions ◽  
Emission Lines ◽  
Be Stars ◽  
Short Overview ◽  
Be Star ◽  
Line Transfer ◽  
Profile Modeling

AbstractIn this talk I give a short overview of models for spectral lines in Be stars disks which I think are quite instructive. I then examine the arguments for my own model assumptions and discuss selected topics concerning radiative line transfer calculations in three dimensions. We show that symmetric Hα emission lines of Be stars can be understood in terms of Keplerian disks. It is also demonstrated that one-armed global disk oscillations provide the best available solution to understand the long-term V/R variations in Be star emission lines.

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