Spectral Variations in the Galaxy NGC 4151

1968 ◽  
Vol 152 ◽  
pp. L113 ◽  
Author(s):  
W. W. Morgan ◽  
Harlan J. Smith ◽  
Daniel Weedman
Keyword(s):  
Ngc 4151 ◽  
The Galaxy

The motion of an emission-line region near the center of the galaxy NGC 4151

2011 ◽  
Vol 55 (9) ◽  
pp. 761-769 ◽  
Author(s):  
E. K. Denissyuk ◽  
R. R. Valiullin ◽  
V. N. Gaisina
Keyword(s):  
Emission Line ◽  
Ngc 4151 ◽  
Line Region ◽  
The Galaxy

scholarly journals Studies of Seyfert galaxies in Fesenkov Astrophysical Institute

2020 ◽  
pp. 61-67
Author(s):  
E. Denissyuk ◽  
R. Valiullin ◽  
CH. Omarov ◽  
S. Shomshekova ◽  
M. Krugov ◽  
...  
Keyword(s):  
Early Stage ◽  
Seyfert Galaxies ◽  
Radiation Detectors ◽  
Light Curves ◽  
Emission Lines ◽  
Main Research ◽  
Ngc 4151 ◽  
The Past ◽  
Photometric Observations ◽  
The Galaxy

This article provides an overview of the main research results of a large group of Seyfert galaxies, carried out at Fesenkov Astrophysical Institute (FAI) over the past 50 years. Spectral observations have been performed since 1970. At an early stage, a three cascade image-tube (UM-92) was used as a radiation receiver. In the 1990s, the equipment was modernized, and at present, the modern CCD cameras are used as radiation detectors at the output of spectrographs. The results of observations were used to determine the absolute fluxes of the emission lines and to study their profiles. Several additional emission features were detected on the wings of the broad emission lines Hα in the spectra of two galaxies NGC 4151 and Ark 120. These features are emitted by compact ionized objects, rotating in the field of Central Body (CB). Photometric observations of Seyfert galaxies have been carried out at FAI since 2010. Light curves of more than 20 Seyfert galaxies have been obtained. In particular, the light curves of the galaxy NGC 4151, obtained last years, shows that an active stage of its nucleus took place in 2015-2016, when the brightness increased by 0m.5 in the V filter, and by almost 2m in the R filter. Then, in 2018-2019 there was a rather sharp decline of brightness, and B V R magnitudes returned to their minimal values.

scholarly journals Seyfert Galaxies

1982 ◽  
Vol 97 ◽  
pp. 179-188 ◽  
Author(s):  
Andrew S. Wilson
Keyword(s):  
Rotation Axis ◽  
Large Fraction ◽  
Large Angle ◽  
Seyfert Galaxies ◽  
Interstellar Gas ◽  
Radio Structure ◽  
Ngc 4151 ◽  
The Galaxy ◽  
Ngc 1068 ◽  
Beam Bending

Observations of sample of Markarian Seyferts with the VLA indicate that a large fraction possess linear radio structure on a scale of a few hundred parsecs to a few kiloparsecs. The radio components generally straddle the optical nucleus and several sources are simple doubles. Similar structures are seen in the classical Seyferts NGC 1068, 4151, and 5548. NGC 4151 is probably best interpreted as a jet. A few sources (e.g. Mark 315, NGC 7469) exhibit diffuse, non-aligned radio structure on a scale similar to that of the linear sources. The radio axis in linear sources is misaligned with respect to the rotation axis of the galaxy disc by a large angle. The linear sources are discussed in terms of a model of a supersonic beam or jet which is “disrupted” by interaction with interstellar gas in the inner part of the galaxy (often a spiral). Two aspects of this interaction are emphasised. Firstly, the curved shape of the radio sources in NGC 1068 and NGC 4151 is ascribed to beam bending by the ram pressure of the rotating interstellar medium. Simple models of this process are shown to be consistent with the observations. Secondly, it is suggested that the broadened forbidden lines in Seyferts originate in part from interstellar gas accelerated outwards by the beam. This picture accounts for some of the empirical correlations found between radio and optical forbidden line properties.

Spectrophotometry of the nucleus of the galaxy ngc 4151 in 1988

1999 ◽  
Vol 17 (5) ◽  
pp. 433-437
Author(s):  
V. V. Prokof'eva ◽  
L. M. Sharipova
Keyword(s):  
Ngc 4151 ◽  
The Galaxy

Spectrophotometric monitoring of the nucleus of the galaxy NGC 4151 at its light minimum in 1988

Astrophysics ◽  
1998 ◽  
Vol 41 (3) ◽  
pp. 214-224
Author(s):  
L. M. Sharipova ◽  
V. V. Prokof’eva
Keyword(s):  
Ngc 4151 ◽  
Light Minimum ◽  
The Galaxy

Statistical criteria of stellar population types

1966 ◽  
Vol 24 ◽  
pp. 101-110
Author(s):  
W. Iwanowska
Keyword(s):  
Stellar Population ◽  
Chemical Properties ◽  
Spectrophotometric Study ◽  
Physical And Chemical Properties ◽  
Population Type ◽  
The Galaxy ◽  
Distribution Parameters ◽  
Physical And Chemical ◽  
Statistical Criteria ◽  
And Chemical Properties

In connection with the spectrophotometric study of population-type characteristics of various kinds of stars, a statistical analysis of kinematical and distribution parameters of the same stars is performed at the Toruń Observatory. This has a twofold purpose: first, to provide a practical guide in selecting stars for observing programmes, second, to contribute to the understanding of relations existing between the physical and chemical properties of stars and their kinematics and distribution in the Galaxy.

Density waves in disk galaxies

1967 ◽  
Vol 31 ◽  
pp. 313-317 ◽  
Author(s):  
C. C. Lin ◽  
F. H. Shu
Keyword(s):  
Mathematical Analysis ◽  
Spiral Structure ◽  
Stellar System ◽  
Collective Modes ◽  
Disk Galaxies ◽  
Spiral Pattern ◽  
Density Waves ◽  
The Galaxy ◽  
Detailed Mathematical Analysis

Density waves in the nature of those proposed by B. Lindblad are described by detailed mathematical analysis of collective modes in a disk-like stellar system. The treatment is centered around a hypothesis of quasi-stationary spiral structure. We examine (a) the mechanism for the maintenance of this spiral pattern, and (b) its consequences on the observable features of the galaxy.

Interstellar gas in the central region of the Galaxy

1967 ◽  
Vol 31 ◽  
pp. 239-251 ◽  
Author(s):  
F. J. Kerr
Keyword(s):  
Central Region ◽  
Galactic Plane ◽  
Neutral Hydrogen ◽  
Continuum Emission ◽  
Galactic Centre ◽  
Interstellar Gas ◽  
Hydrogen Recombination ◽  
The Galaxy ◽  
Centre Region ◽  
The Relationship

A review is given of information on the galactic-centre region obtained from recent observations of the 21-cm line from neutral hydrogen, the 18-cm group of OH lines, a hydrogen recombination line at 6 cm wavelength, and the continuum emission from ionized hydrogen.Both inward and outward motions are important in this region, in addition to rotation. Several types of observation indicate the presence of material in features inclined to the galactic plane. The relationship between the H and OH concentrations is not yet clear, but a rough picture of the central region can be proposed.

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