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The Second Byurakan Survey - The Final Results. The Multiwavelength AGN Survey in the SBS Area

Published online by Cambridge University Press:  12 April 2016

J.A. Stepanian  and
V.H. Chavushyan
J.A. Stepanian
Affiliation:
Instituto de Astronomia, Universidad Nacional Autonoma de México, A.P. 70-264, México D.F. 04510, México
V.H. Chavushyan
Affiliation:
Instituto Nacional de Astrofísica Optica y Electrónica, A.P. 51 y 216, C.P. 72000, Puebla, Pue., México

Abstract

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On the basis of the Second Byurakan Survey (SBS) we have produced the largest and most homogeneous new complete samples of faint Markarian galaxies, Sy galaxies and bright QSOs. The General Catalogue of the SBS Survey, which is completed and prepared for publication, contains the data for more than 3600 objects, half of which are star-like objects while the other half are galaxies. Nearly 2500 slit spectra were obtained for about 2100 SBS objects. 561 new QSOs and AGNs in the magnitude range 15.5 < B < 19.5 with redshifts 0.0 < z <3.2 were spectroscopically confirmed. A sample of 17 BLL has been isolated as well.

The volume for reliable investigation of faint Markarian UVX galaxies has been extended out to a distance of about ~ 500 Mpc, more than 50 times deeper than in the FBS. Faint Markarian UVX galaxies from the SBS survey comprise ~ 12% of field galaxies, slightly greater than in the First Markarian survey; ~ 10% of them (~ 120) turned out to be Sy galaxies.

A complete sample of faint (B ≤ 17.0, z ≤ 0.1) Sy galaxies has been constructed. In the spatial volume with radius of about 500 Mpc, the relative number of AGNs is 1.2% of field galaxies. One of the most complete and representative samples of bright QSOs (~ 130) in the magnitude range 15.7 < B ≤ 17.5 with redshifts 0.3 ≤ z ≤ 2.2 has been constructed as well.

The objects in the combined complete sample of SBS Sy galaxies and QSOs might be roughly divided into two groups: classical Sy galaxies and QSOs in agreement with the previous classification scheme and nonclassical SyG and QSOs for which the existing classification scheme is not sufficient for their classification. The presence of narrow line QSOs (NLQSOs) or so-called QSO II type objects is established. There is a continuous transition of all properties between all types of Sy galaxies and QSOs, from Liners through Sy2, NLSyls, BLSyl to NLQSOs and BLQSOs.

Preliminary results from the Multiwavelength AGN Survey (MWAGN) in X-ray, Radio and IR wavebands in the SBS area are presented. The MWAGN survey in the SBS area shows that the ROSAT or FIRST surveys by themselves cannot represent the whole AGN/QSO sample. The ROSAT Bright sources along with the FIRST sources comprise only 25% of the whole SBS QSO sample. The IRAS survey is effective for a redshift less than z < 0.05. All classical Sy2s but only ~ 50% of classical Syls are IRAS sources. Luminous and Ultraluminous IRAS SBS AGNs comprise ~ 25% of the whole AGN sample. The greater part of SBS AGN/QSOs are neither ROSAT nor FIRST nor IRAS LIG or ULIG sources. They are optically emitting AGN/QSOs.

The multiwavelength “complete” sample of bright QSOs in the SBS area allows us to conclude that the fast evolution of bright QSOs is more likely the result of a selection effect than the result of fast cosmological evolution. The LogN-B relation for these QSOs reduces to the value LogN − B = 0.67 ± 0.005.

A direct empirical estimate of the effect of overlapping images is obtained from the MWAGN survey. The effect of overlap comprises ~ 5% for QSOs brighter than B ≤ 17.0 and ~ 10% for QSOs brighter than B ≤ 17.5.

Type
Part 1. Optical Surveys for AGN
Information
International Astronomical Union Colloquium , Volume 184: AGN Surveys , 2002 , pp. 23 - 32
Copyright
Copyright © Astronomical Society of the Pacific 2002

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