The discovery of an O VII emission line in the ASCA spectrum of the Seyfert galaxy NGC 3783

1995 ◽  
Vol 438 ◽  
pp. L67 ◽  
Author(s):  
I. M. George ◽  
T. J. Turner ◽  
H. Netzer
Keyword(s):  
Emission Line ◽  
Seyfert Galaxy

scholarly journals Hour-timescale profile variations in the broad Balmer lines of the Seyfert galaxy Hour-timescale profile variations in the broad Balmer lines of the Seyfert galaxy Markarian 6

2013 ◽  
Vol 9 (S304) ◽  
pp. 407-408
Author(s):  
Norayr S. Asatrian
Keyword(s):  
Fine Structure ◽  
Emission Line ◽  
Sampling Rate ◽  
Seyfert Galaxy ◽  
Special Astrophysical Observatory ◽  
Balmer Line ◽  
Line Profiles ◽  
Balmer Lines ◽  
Profile Changes ◽  
Hydrogen Emission Line

AbstractPart of results of the multi-epoch intranight optical spectroscopic monitoring of the Markarian 6 nucleus carried out at the telescopes of 6-m of the Special Astrophysical Observatory (Russia), 2.6-m of the Byurakan Astrophysical Observatory (Armenia) and 2-m of the Tautenburg Observatory (Germany) is presented.Observations were made in 1979, 1986, 1988-1991 and 2007-2009 during a total of 33 nights with an average sampling rate of 4 spectra per night. TV-scanner and long-slit spectrographs equipped with Image Tube and CCD detector arrays were used. Altogether we analyzed 110 Hβ and 58 Hα region spectra to search for intranight variability in the broad hydrogen emission line profiles. The typical spectral resolutions were 4 Å for scanner spectra, 6 Å for photographic spectra, and 5 Å and 10 Å for CCD spectra. The S/N ratio at the continuum level near the Hβ and Hα lines was in the range 15–50.The purpose of the search was to look for the characteristic variability signatures of different kinematical models of the broad emission-line region. We considered the centering and guiding errors which can result in differences between spectra.We found variations in the broad Balmer line difference profiles on time scale of hour with the level of significance of 3.6 σ to 5.0 σ. Variations take the form of narrow, small bumps located at the blue and red sides or only at the blue side of the lines. In the intermediate level of broad line flux, the Hβ and Hα profiles show fine structure. Detected profile changes occurred at the same radial velocity shifts as the details in the fine structure.The variability is at least 2 orders of magnitude more rapid than any observed for broad Balmer line profiles in AGNs that we are aware of in the literature.Discovered extremely rapid line-profile variability may be associated with reverberation effects. Two-sided profile changes may indicate the response of circularly rotating hydrogen clouds in the BLR to a light pulse from a central source. One-sided profile variations may be attributed to a response of a non-disk component: the subarcsec scale region of the jet.

High Velocity Outflow in the Extended Emission-Line Region of the Seyfert Galaxy NGC 7319

1996 ◽  
Vol 111 ◽  
pp. 140 ◽  
Author(s):  
Kentaro Aoki ◽  
Hiroshi Ohtani ◽  
Michitosh Yoshida ◽  
George Kosugi
Keyword(s):  
Emission Line ◽  
High Velocity ◽  
Seyfert Galaxy ◽  
Line Region ◽  
Extended Emission

scholarly journals The extended emission-line region of the Seyfert galaxy Mrk 573

1999 ◽  
Vol 309 (1) ◽  
pp. 1-25 ◽  
Author(s):  
P. Ferruit ◽  
A. S. Wilson ◽  
H. Falcke ◽  
C. Simpson ◽  
E. Pecontal ◽  
...  
Keyword(s):  
Emission Line ◽  
Seyfert Galaxy ◽  
Line Region ◽  
Extended Emission

scholarly journals Deep spectroscopy of the dwarf spheroidal NGC 185

2011 ◽  
Vol 7 (S283) ◽  
pp. 370-371
Author(s):  
Denise R. Gonçalves ◽  
Laura Magrini ◽  
Lucimara P. Martins ◽  
Ana M. Teodorescu ◽  
Cintia Quireza ◽  
...  
Keyword(s):  
Emission Line ◽  
Chemical Evolution ◽  
Dwarf Galaxies ◽  
Seyfert Galaxy ◽  
Ionization Mechanisms ◽  
The Galaxy ◽  
Nearby Galaxies ◽  
Formation And Evolution ◽  
Nuclear Regions ◽  
Galaxy Population

AbstractDwarf galaxies are crucial to understand the formation and evolution of galaxies, since they constitute the most abundant galaxy population. Abundance ratios and their variations due to star formation and inflow/outflow of gas are key constraints to chemical evolution models. The determination of these abundances in the dwarf galaxies of the Local Universe is thus of extreme importance. NGC 185 is one of the four brightest dwarf companions of M31, but unlike the other three it has an important content of gas and dust. Interestingly enough, in an optical survey of bright nearby galaxies NGC 185 was classified as a Seyfert galaxy based on its integrated emission-line ratios in the nuclear regions. However, although its emission lines formally place it in the category of Seyfert it is probable that this galaxy does not contain a genuine active nucleus. In this contribution, we resume, firstly, our results of an empirical study of the galaxy, on which we characterise its emission-line population and obtain planetary nebulae abundance ratios (Gonçalves et al. 2012). And, secondly, we discuss our attempt to identify the possible ionization mechanisms for NGC 185 enlighting the controversial classification of this galaxy dwarf spheroidal (dSph) as well as Seyfert, via stellar population synthesis and chemical evolution modelling (Martins et al. 2011).

scholarly journals The Far‐Infrared Emission Line and Continuum Spectrum of the Seyfert Galaxy NGC 1068

2005 ◽  
Vol 623 (1) ◽  
pp. 123-136 ◽  
Author(s):  
Luigi Spinoglio ◽  
Matthew A. Malkan ◽  
Howard A. Smith ◽  
Eduardo Gonzalez‐Alfonso ◽  
Jacqueline Fischer
Keyword(s):  
Emission Line ◽  
Seyfert Galaxy ◽  
Far Infrared ◽  
Infrared Emission ◽  
Continuum Spectrum ◽  
Ngc 1068

The behaviour of the hα emission line in the spectrum of Seyfert galaxy NGC4151 from 1976–1999

2001 ◽  
Vol 20 (2) ◽  
pp. 337-338 ◽  
Author(s):  
E. K. Denissyuk ◽  
R. R. Valiullin ◽  
R. W. Argyle ◽  
V. N. Gaisina ◽  
O. Karpova
Keyword(s):  
Emission Line ◽  
Seyfert Galaxy ◽  
Hα Emission

scholarly journals High-Ionization Nuclear Emission-Line Region in the Seyfert Galaxy Tololo 0109−383

1998 ◽  
Vol 115 (2) ◽  
pp. 460-471 ◽  
Author(s):  
Takashi Murayama ◽  
Yoshiaki Taniguchi ◽  
Kazushi Iwasawa
Keyword(s):  
Emission Line ◽  
Seyfert Galaxy ◽  
Line Region ◽  
High Ionization

scholarly journals Variability of the Emission Line Spectrum of the Nucleus of Seyfert Galaxy NGC 1275

1974 ◽  
Vol 58 ◽  
pp. 341-345
Author(s):  
I. Pronik
Keyword(s):  
Emission Line ◽  
Seyfert Galaxy ◽  
Emission Lines ◽  
Line Spectrum ◽  
Spectroscopic Observations ◽  
Emission Line Spectrum ◽  
Ngc 1275

Recent spectroscopic observations of the nucleus of NGC 1275, together with results from earlier workers, confirm the variability of the emission lines and indicate corresponding variations in the electron temperatures and densities of different zones. These changes may be associated with the microwave outbursts from this source.

A detailed study of the CIV 1550 line profile and adjacent spectral features in NGC 4151 from 1978 up to 1983

1986 ◽  
Vol 119 ◽  
pp. 351-352
Author(s):  
J. Clavel ◽  
A. Altamore ◽  
A. Boksenberg ◽  
G.E. Bromage ◽  
A. Elvius ◽  
...  
Keyword(s):  
Emission Line ◽  
Line Profile ◽  
Seyfert Galaxy ◽  
Spectral Features ◽  
Continuum Source ◽  
Ngc 4151 ◽  
The Continuum

Fitting technics are applied to study the variations of the 1550 line profile and adjacent features in the IUE spectrum of the Seyfert galaxy NGC 4151, from 1978 up to 1983. New important results are found concerning the kinematics and physics of the emission line gas at a few light-days from the continuum source.

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