Spectral energy distribution and long-term variations in gamma cassiopeiae
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view Abstract Citations References (1) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Broad Emission Line Profiles and Profile Variability of the Seyfert 1 Galaxy Arakelian 120: Erratum Korista, Kirk T. Abstract In the paper "The Broad Emission Line Profiles and Profile Variability of the Seyfert 1 Galaxy Arakelian 120" by Kirk T. Korista (ApJS, 79,285 [1992]), an error appears in Table 5. In experiment 1 the positions and FWHMs of the broad emission line components for Julian Date 2,447,788 are listed incorrectly. They should be exactly the same as the positions and FWHMs for Julian Date 2,447,582, listed just above, as explained in the text. The corrected Table 5 is given below. [See Journal] Publication: The Astrophysical Journal Supplement Series Pub Date: September 1992 DOI: 10.1086/191723 Bibcode: 1992ApJS...82..445K Keywords: ERRATA; ADDENDA full text sources ADS | Related Materials (1) Original Paper: 1992ApJS...79..285K
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view Abstract Citations (35) References (42) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Broad Emission-Line Profiles and Profile Variability of the Seyfert 1 Galaxy Arakelian 120 Korista, Kirk T. Abstract We present Hα and Hβ broad emission-line profiles of the Seyfert galaxy Arakelian 120 from the past ~10 yr, representing over 100 spectroscopic observations. The broad emission-line profiles of the Balmer lines are complex in structure and variable; the profile variations themselves are complex. We attempt to isolate separate emitting components within the profiles through profile differencing and profile fitting. If Gaussian-like, at least four separate components are present in the broad Balmer emission lines. The broad emission-line profiles of other emission lines (optical and UV) are also presented, and evidence is given for a stratified BLR. Using the results of Joly, we demonstrate that the Fe II multiplets 25 and 36 (in addition to m42) may be present in the Hβ profile and in its "red shelf." Publication: The Astrophysical Journal Supplement Series Pub Date: April 1992 DOI: 10.1086/191654 Bibcode: 1992ApJS...79..285K Keywords: Emission Spectra; Line Spectra; Seyfert Galaxies; Astronomical Spectroscopy; Balmer Series; Charge Coupled Devices; H Alpha Line; H Beta Line; Astrophysics; GALAXIES: INDIVIDUAL NAME: ARAKELIAN 120; GALAXIES: SEYFERT; LINE: PROFILES full text sources ADS | data products SIMBAD (6) NED (1) MAST (1) Related Materials (1) Erratum: 1992ApJS...82..445K
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In this second paper in a series of three, we study the properties of the various emission features and underlying continuum in the optical spectra of type 1 active galactic nuclei (AGNs) by using the unobscured hard X-ray emission as a diagnostic. We introduce the use of the 'correlation spectrum technique' (CST) for the first time. We use this to show the strength of the correlation between the hard X-ray luminosity and each wavelength of the optical spectrum. This shows that for broad-line Seyfert 1 galaxies all the strong emission lines (the broad component of Hα and Hβ, [Ne iii] λλ3869/3967, [O i] λλ6300/6364, [O ii] λλ3726/3729 and [O iii] λλ4959/5007) and the optical underlying continuum all strongly correlate with the hard X-ray emission. In contrast, the narrow-line Seyfert 1 galaxies show a stronger correlation in the optical continuum but a weaker correlation in the lines.
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Optical high-resolution spectroscopic observations of the emission-line star MWC645 are presented. The spectrum exhibits strong variable double-peaked Balmer emission lines as well as low-excitation emission lines of FeII, [FeII], and [OI] which are signatures of the B[e] phenomenon, while lines of helium have not been found. In addition to the emission lines, for the first time we identified absorption lines of neutral metals (e.g., LiI 6708 A, CaI 6717 A, and a number of FeI and TiI lines) that indicate the presence of a cool component in the system. The heliocentric radial velocity measured in our best spectrum was found to be −65.1±1.0 kms −1 for the emission lines and −23.2±0.4 kms −1 for the absorption lines. Using a combination of photometric and spectroscopic data as well as the Gaia EDR3 distance (D=6.5±0.9 kpc), we disentangled the component contributions and estimated their temperatures and luminosities (∼15000 K and ∼4000 K, log L/L ? = 3.8±0.2 and 2.8±0.2 for the hot and cool component, respectively).
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In our paper (Ch. Fehrenbach and C.C. Huang, 1981) we have described the details of our spectroscopic observations of CI Cyg in 1980. In that year, the star showed a fair presence of bright forbidden lines of [FeV ]and very strong emission lines of high and low excitation, including forbidden [0 III ] , [Ne III], [Fe II ] and [S II] and permitted 0 III, N III as well as He I and Fe II … etc … The He II 4686 A was very strong. The Balmer lines were the strongest emission features in the spectrum and H α and H β were double. There were two groups of velocities in 1980, one was positive for forbidden lines and the other was negative for the permitted lines. The displacements of Balmer lines showed a regression.
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We present phase-resolved optical spectroscopy of the eclipsing nova-like cataclysmic variable EC21178-5417 obtained between 2002 and 2013. The average spectrum of EC21178-5417 shows broad double-peaked emission lines from HeII 4686 \AA{} (strongest feature) and the Balmer series. The high-excitation feature, CIII/NIII at 4640-4650 \AA{}, is also present and appears broad in emission. A number of other lines, mostly HeI, are clearly present in absorption and/or emission. The average spectrum of EC21178-5417 taken at different months and years shows variability in spectral features, especially in the Balmer lines beyond H$\gamma$, from pure line emission, mixed line absorption and emission to pure absorption lines. Doppler maps of the HeII 4686 \AA{} emission reveal the presence of a highly-inclined asymmetric accretion disc and a two spiral arm-like structure, whereas that of the Balmer lines (H$\alpha$ and H$\beta$) reveal a more circular accretion disc. There is no evidence of a bright spot in the Doppler maps of EC21178-5417 and no emission from the secondary star is seen in the tomograms of the HeII 4686 \AA{} and Balmer lines. Generally, the emission in EC21178-5417 is dominated by emission from the accretion disc. We conclude that EC21178-5417 is a member of the RW Tri or UX UMa sub-type of nova-like variables based on these results and because it shows different spectral characteristics at different dates. This spectral behaviour suggests that EC21178-5417 undergoes distinct variations in mass transfer rate on the observed time scales of months and years.
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New optical spectra of the original narrow-line quasar 1E 0449.4-1823 show that it now has broad emission lines of considerable strength, eliminating it as a "type 2 QSO" candidate. Although broad emission line components were probably weakly present in 1981 and 1984, they have certainly increased in strength and are accompanied by Balmer continuum emission that makes the spectrum bluer than it was previously. We suggest that the behavior of 1E 0449.4-1823 is the same as that of some Seyfert 1.8 and 1.9 galaxies, in which Goodrich attributed long-term variations of their broad Balmer lines to dynamical motions of obscuring material located in or around the broad-line region. The optical continuum and broad emission line regions of 1E 0449.4-1823 may still be partly covered in our line of sight, which would explain its large forbidden-line equivalent widths and flat αox relative to other low-redshift QSOs. Also present are apparent absorption features in the broad Balmer lines and in Mg II, which may be related to the past obscuration and current emergence of the broad-line region. However, it is difficult to distinguish absorption from broad emission line peaks that are displaced in velocity; we consider the latter a plausible competing interpretation of these peculiar line profiles. An ASCA X-ray spectrum of 1E 0449.4-1823 can be fitted with a power law of Γ=1.63+ 0.12−0.09, intrinsic NH < 9 × 1020 cm-2, and no Fe Kα line emission. Its 2-10 keV luminosity is 6.7 × 1044 ergs s-1. Thus, there is no evidence for Seyfert 2 properties in the X-ray emission from 1E 0449.4-1823, which resembles that of an ordinary QSO. With regard to the still hypothetical type 2 QSOs, we argue that there is little evidence for the existence of any among X-ray-selected samples.
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Spectra show a rich emission line spectrum including permitted lines of neutral and once ionized iron-peak elements. P Cygni emission from the Balmer lines and calcium K is also seen – the absence of H emission is explained by neutral iron absorption and results in flourescent emission. The simple physical and geometrical model discussed in the Conclusion seems capable of qualitatively explaining all the data.
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