Observational Effects of Interaction in the Seyfert galaxy NGC 7469

AbstractSome pecularities of the circummucleus of the Seyfert galaxy NGC 7469 were revealed, plausibly caused by interaction with the satellite IC 5283 and a starlike detail, situated on the edge of the west spiral branch 14” from the nucleus. Shock excited HII regions were noted in the part of NGC 7469 turned toward the satellite IC 5283. The galaxy’s central radio structure (λ ~ 6 cm) stretches in the direction toward the satellite IC 5283 and the starlike detail. The spectum and color index of the starlike detail suggest that it is a cluster of early type stars (Mv = -19m) and dust clouds (Av = 3m), in NGC 7469.

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Preliminary Observations of Interstellar Sodium D-Line Absorption towards the Carina Nebula

Publications of the Astronomical Society of Australia ◽

10.1017/s1323358000018944 ◽

1980 ◽

Vol 4 (1) ◽

pp. 95-97 ◽

Cited By ~ 3

Author(s):

J. B. Whiteoak ◽

F. F. Gardner

Keyword(s):

High Resolution ◽

Hii Regions ◽

Early Type ◽

Interstellar Clouds ◽

Carina Nebula ◽

Line Absorption ◽

General Investigation ◽

Early Type Stars ◽

Resolution Study

As part of a general investigation of interstellar clouds associated with southern HII regions we have begun a high-resolution study of the sodium D-line absorption in the directions of early-type stars that are likely to be associated with or located behind the clouds.

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Area Spectroscopy of the Extended Emission Line Region in the Seyfert Galaxy NGC 3516

International Astronomical Union Colloquium ◽

10.1017/s0252921100022958 ◽

1995 ◽

Vol 149 ◽

pp. 203-204

Author(s):

K. Aoki ◽

H. Ohtani ◽

G. Kosugi ◽

M. Yoshida

Keyword(s):

Emission Line ◽

Radiation Field ◽

Seyfert Galaxy ◽

Hii Regions ◽

Nuclear Radiation ◽

Ngc 4151 ◽

Dust Clouds ◽

Line Region ◽

Extended Emission

The researches into extended emission line region (EELR) give us the valuable informations about the nucleus. A recent study of the EELR in the Seyfert 1 galaxy NGC 4151 by Yoshida and Ohtani (1993) have revealed that a strongly asymmetric radiation field in this typical Seyfert 1. They have suggested the anisotropy may be caused inside the BLR. It is important to examine if any other Seyfert 1 galaxy has an anisotropic nuclear radiation.The famous Seyfert 1 galaxy NGC 3516 has EELR which extends ∼ 10” on either side of the nucleus. The morphology of the EELR is Z-shape. This nearby (D=38.9Mpc) galaxy is of type SBO for which the object is expected to be free from contamination by HII regions and dust clouds.

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Environs of HII Regions

Publications of the Astronomical Society of Australia ◽

10.1017/s1323358000016696 ◽

1983 ◽

Vol 5 (2) ◽

pp. 158-162 ◽

Cited By ~ 1

Author(s):

R. S. Roger

Keyword(s):

Molecular Clouds ◽

Hii Regions ◽

Low Density ◽

Dust Grains ◽

Early Type ◽

Hydrogen Atoms ◽

Interstellar Gas ◽

Early Type Stars ◽

Stable Surfaces ◽

Dust Absorption

It is generally agreed that early-type stars, and hence their HII regions, appear to develop preferentially in dense concentrations within molecular clouds. These parent molecular clouds owe their existence in two ways to the dust grains in the interstellar gas, a component which comprises about 1% by mass. First, dust grains provide stable surfaces upon which hydrogen atoms can come together to form molecules. Then, once formed, the molecules are protected in cloud interiors by dust absorption of the dissociating ultraviolet radiation which pervades the low-density interstellar medium.

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Some results of the Barbier-Chalonge-Divan system of stellar classification

Symposium - International Astronomical Union ◽

10.1017/s0074180900053250 ◽

1966 ◽

Vol 24 ◽

pp. 77-90 ◽

Cited By ~ 1

Author(s):

D. Chalonge

Keyword(s):

Early Type ◽

Parameter System ◽

Early Type Stars ◽

Two Parameter

Several years ago a three-parameter system of stellar classification has been proposed (1, 2), for the early-type stars (O-G): it was an improvement on the two-parameter system described by Barbier and Chalonge (3).

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Radio Continuum Measurements of Southern Early‐Type Stars. III. Nonthermal Emission from Wolf‐Rayet Stars

The Astrophysical Journal ◽

10.1086/307314 ◽

1999 ◽

Vol 518 (2) ◽

pp. 890-900 ◽

Cited By ~ 64

Author(s):

Jessica M. Chapman ◽

Claus Leitherer ◽

Barbel Koribalski ◽

Roderick Bouter ◽

Michelle Storey

Keyword(s):

Radio Continuum ◽

Early Type ◽

Nonthermal Emission ◽

Early Type Stars

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Chemical Abundances of Early Type Stars

Symposium - International Astronomical Union ◽

10.1017/s007418090011486x ◽

1998 ◽

Vol 188 ◽

pp. 224-225

Author(s):

S. Tanaka ◽

S. Kitamoto ◽

T. Suzuki ◽

K. Torii ◽

M.F. Corcoran ◽

...

Keyword(s):

Surface Layer ◽

Stellar Wind ◽

Nuclear Reactions ◽

X Rays ◽

Early Type ◽

Chemical Abundances ◽

X Ray ◽

Low Metallicity ◽

Early Type Stars

X-rays from early-type stars are emitted by the corona or the stellar wind. The materials in the surface layer of early-type stars are not contaminated by nuclear reactions in the stellar inside. Therefore, abundance study of the early-type stars provides us an information of the abundances of the original gas. However, the X-ray observations indicate low-metallicity, which is about 0.3 times of cosmic abundances. This fact raises the problem on the cosmic abundances.

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UV Spectral Classification of B Stars

Symposium - International Astronomical Union ◽

10.1017/s0074180900079092 ◽

1985 ◽

Vol 111 ◽

pp. 411-413

Author(s):

Janet Rountree ◽

George Sonneborn ◽

Robert J. Panek

Keyword(s):

Classification System ◽

Classification Criteria ◽

High Dispersion ◽

Spectral Classification ◽

Early Type ◽

B Stars ◽

Dimensional Classification ◽

Early Type Stars ◽

Comprehensive Classification

Previous studies of ultraviolet spectral classification have been insufficient to establish a comprehensive classification system for ultraviolet spectra of early-type stars because of inadequate spectral resolution. We have initiated a new study of ultraviolet spectral classification of B stars using high-dispersion IUE archival data. High-dispersion SWP spectra of MK standards and other B stars are retrieved from the IUE archives and numerically degraded to a uniform resolution of 0.25 or 0.50 Å. The spectra (in the form of plots or photowrites) are then visually examined with the aim of setting up a two-dimensional classification matrix. We follow the method used to create the MK classification system for visual spectra. The purpose of this work is to examine the applicability of the MK system (and in particular, the set of standard stars) in the ultraviolet, and to establish classification criteria in this spectral region.

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The Use of Model Atmospheres for Temperature-Gravity Calibration

Symposium - International Astronomical Union ◽

10.1017/s0074180900055261 ◽

1973 ◽

Vol 54 ◽

pp. 173-221

Author(s):

J. C. Pecker

Keyword(s):

Model Building ◽

Stellar Atmosphere ◽

Line Formation ◽

Early Type ◽

New Concepts ◽

Total Luminosity ◽

Classical Models ◽

Early Type Stars ◽

Two Parameters

Regardless of the degree of elaboration of series of models, just how can they be used for calibration purposes? And how much is this calibration sensitive to the quality of the model theory? These two questions are the basis of our discussion, which covers : I – The general principles of the use of model atmospheres in stellar calibration (1 – The two dimensional classifications; 2 – The use of the total luminosity; 3 – The cases of Vega and Sirius; 4 – The calibration of ST – Teff relation); II – The failures of the two parameters model atmospheres (1 – The observational need for more-than-two-parameters classification; 2 – The abundance of elements, the line formation, and the model atmospheres; 3 – Various sources of unadequacy of models; 4 – Envelopes or shell features; their influence on model-building; 5 – The case of HD 45677. Diagnostic of early-type stars; 6 – Various unexplained spectral features); III – The present state of the model factory (1 – The classical models; 2 – New concepts in the description of a stellar atmosphere; 3 – New approaches in model making; 4 – Conclusions).

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