Radio to X-ray properties of starburst and active galactic nuclei

Other Title(s)

خواص الأشعة من الراديوية إلى السينية في المجرات ذات الانفجارات النجمية و النويات الفعالة المجرية

Dissertant

Bani Ahmad, Ali Mahmud

Thesis advisor

Kandalyan, Rafiq A.
Karim, Layth Mahmud

University

University of Baghdad

Faculty

College of Science

Department

Astronomy and Space Department

University Country

Iraq

Degree

Ph.D.

Degree Date

2006

English Abstract

The radio and x-ray observations are an excellent means of probing the matter within the central part of a galaxy.

The radio and hard x-ray electromagnetic waves from the nuclear starburst or Active Galactic Nuclei (AGN ) may penetrate the dense material found in galaxies.

Both starburst and AGN can produce IR, X-ray and radio emission.

Both energy sources may be present in the same galaxy and they have different observational properties, however quantitative observational data are needed to decide which is energetically dominant.Comparison of the global properties of galaxies at different wavelengths, from radio to X-rays can give us insight on the formation and evolution of galaxies.

Samples of starburst and AGN selected from X-ray observatories - ROSAT, CHANDRA & XMM-Newton and samples of the brightest X-ray sources have been selected of the following galaxies types : Seyfert type 1 (Sy1), Seyfert type 2 (Sy2), Low Ionization Nuclear Emission-line Regions (LINER), Narrow Line Seyfert 1(NS) and Qusi-Stellar Objects (QSOs).

The samples are large enough and unbiased for detail study of multifrequency ( radio to X-ray) properties of these galaxies.

Particularly, the Xray properties of these galaxies for different Black Hole masses.

Meanwhile the core radio dominance, spectral index, two-point radio-tooptical and optical-to-X-ray spectral indices have been discussed for different activity types.

The broadband (from the radio to the X-ray) properties of AGN galaxies has been examined based on unbiased sample of galaxies in order to elucidate the physical differences between them , and deduced that these were due to both the variable obscuration and different geometric orientation effects.

The correlation between the X-rays, Radio and Infrared luminosities have been studies to understand the Black Hole or Starburst influence .The possible effects of the extended X-ray and Radio components have been quantitatively discussed.

All necessary parameters (luminosities , spectral indices and accretion rate ) are calculated, by using the methods of modern mathematical statistics, like multiple regression analysis , non-parametric statistics to analyze the possible relation between different parameters It is found that AGNs are powered by the central Black Hole and the correlation between X-ray and radio emission over many decades is primary and it indicates on intrinsically similar origin of both radiations in Seyfert galaxies powered mainly by AGN, rather than by compact starbursts.

Slopes between two-point spectral indices (RO and (OX for Sy1s, Sy2s ,LINERs, NS and QSO's were found less steep than those for radio galaxies and quasars .

It has shown that the X-ray emission of the nuclear region of AGN possesses both compact and extended components, and AGNs and Starburst activities often co-exist .The OH megamaser galaxies are the advection-dominated accretion flows (ADAF)-dominated objects .

Main Subjects

Astronomy

Topics

• Astronomy
• Galaxies
• Active galactic nuclei

No. of Pages

116

Table of Contents

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-604458