Journal or Publication Title:

Բյուրականի աստղադիտարանի հաղորդումներ: Երևանի աստղադիտարանի բյուլետեն = Сообщения Бюраканской обсерватории. Бюллетень ереванской Астрономической обсерватории = Contributions from the Burakan observatory. Bulletin of the Erevan astronomical observatory

Date of publication:

2025

Volume:

72

Number:

2

ISSN:

2579-2276

Coverage:

401-408

Abstract:

We have created a general catalogue of AGN selected from optical identifications of X-ray sources using two sources: Hamburg-ROSAT Catalogue (HRC) and Byurakan-Hamburg-ROSAT Catalogue (BHRC). Both contain optical identifications of X-ray sources from ROSAT catalogues based on low-dispersion spectra of Hamburg Quasar Survey (HQS). HRC used ROSAT Bright Source Catalogue (BSC) and BHRC used brighter sources of ROSAT Faint Source Catalogue (FSC), thus extending the sample to count rates (CR) of photons ≥ 0.04 ct/s in the area with galactic latitudes |b| ≥ 20◦ and declinations δ ≥ 0◦ (the area of HQS). However, HRC and BHRC contain a number of misidentifications, and by using the recent optical and multiwavelength (MW) catalogues we have revised both samples excluding false AGN and adding new genuine AGN. As a result, a new homogeneous complete sample of 4253 X-ray selected AGN was created (ROSAT BSC/FSC AGN). For these sources we retrieved all multiwavelength data from recent catalogues and carried out statistical investigations. An attempt to find connections between the radiation fluxes in different bands for different types of sources, and identify their characteristics thus confirming candidate AGNs have been done. We have analyzed X-ray properties of these sources to find a limit between normal galaxies and X-ray AGN. In this study we carry out detailed spectral classification of AGN candidates from the Joint HRC/BHRC sample. These objects were revealed as optical counterparts for ROSAT X-ray sources, however spectra of them are given in SDSS without definite spectral classification. We studied these objects using the SDSS spectra and revealed the detailed activity types for them. Three diagnostic diagrams and direct examination of the spectra were used to have more confident classification.

Format:

pdf

Identifier:

oai:arar.sci.am:426400

General note:

Communications of the Byurakan Astrophysical Observatory (ComBAO) is a peer-reviewed scientific journal, which publishes research in observational and theoretical astronomy/astrophysics and presents recent advances in these fields. It is being published by the NAS RA V. Ambartsumian Byurakan Astrophysical Observatory (BAO) in English in electronic form. The journal publishes original papers, review papers, brief reports, book reviews, special communications, observational and theoretical results in various fields of astronomy and related sciences, and some editorial notes, including anniversaries and obituaries. Under the heading “Legacy”, the renewed magazine will republish some old articles of high value in English. The heading “Guest articles” will bring to the attention of readers the articles of researchers who are not employees of BAO. ComBAO was founded in 1946 and regularly published in 1946-1990. However, the publication was interrupted because of the economic situation after the disintegration of the Soviet Union in 1991.

Location of original object:

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