Investigation of a New Sample of IRAS Galaxies

The Byurakan Astrophysical Observatory (BAO) has always been one of the centres for surveys and studies of active galaxies. Here we review our search and studies of active galaxies during last 30 years using various wavelength ranges, as well as some recent related works. These projects since late 1980s were focused on multiwavelength search and studies of AGN and Starbursts (SB). 1103 blue stellar objects (BSOs) on the basis of their UV-excess were selected using Markarian Survey (First Byurakan Survey, FBS) plates and Markarian’s criteria used for the galaxies. Among many blue stars, QSOs and Seyfert galaxies were found by follow-up observations. 1577 IRAS point sources were optically identified using FBS lowdispersion spectra and many AGN, SB and high-luminosity IR galaxies (LIRG/ULIRG) were discovered. 32 extremely high IR/opt flux ratio galaxies were studies with Spitzer. 2791 ROSAT FSC sources were optically identified using Hamburg Quasar Survey (HQS) lowdispersion spectra and many AGN were discovered by follow-up observations. Fine analysis of emission line spectra was carried out using spectral line decomposition software to establish true profiles and calculate physical parameters for the emitting regions, as well as to study the spectral variability of these objects. X-ray and radio selection criteria were used to find new AGN and variable objects for further studies. We have estimated AGN content of X-ray sources as 52.9%. We have also combined IRAS PSC and FSC catalogs and compiled its extragalactic sample, which allowed us to estimate AGN content among IR sources as 23.7%. Multiwavelength approach allowed revealing many new AGN and SB and obtaining a number of interesting relations using their observational characteristics and physical properties.

Section: Optical Identification Of Iras Psc Sources and Big Samplementioning

confidence: 99%

Multiwavelength Search and Studies of Active Galaxies and Quasars

Mickaelian

2017

“…BIG objects have been studied spectroscopically using BAO 2.6 m (Mickaelian et al, 2003, Special Astrophysical Observatory (SAO, Russia) 6 m (Balayan et al, 2001, Mickaelian et al, 1998, Observatoire de Haute-Provence (OHP, France) 1.93 m (Mickaelian, 2004) telescopes and the Sloan Digital Sky Survey (Abolfathi et al, 2018) (Mickaelian et al, 2018). Altogether 255 BIG objects have been studied and classified.…”

Section: Introductionmentioning

confidence: 99%

Building the Largest Sample of IR Galaxies. Preliminary Results

Mikayelyan,

Mickaelian,

Abrahamyan

et al. 2024

To build the IRAS full extragalactic sample (including both point-like sources - QSOs, and extended ones - galaxies), we have applied several approaches. Cross-correlation of IRAS PSC/FSC Combined Catalogue with optical catalogues of already known galaxies, quasars and blazars such as The NGC 2000.0 Catalog, Third Reference Catalogue of Bright Galaxies, The Roma BZCAT, Astrometric Catalogue 5 and many others. Cross-correlation of IRAS PSC/FSC Combined Catalogue with optical catalogues giving data, which can be used to determine galaxy candidates, for example Sloan Digital Sky Survey (SDSS, contains data about point like and extended objects), The APM North Catalogue (contains data about ellipticity of objects), etc. Cross-correlation of IRAS PSC/FSC Combined Catalogue with GAIA DR3, which gives data about proper motions of objects (we can consider the objects having real proper motions as stars and exclude them from the sample). If all data show the same type of object, then we give it as a genuine one, and if there is an ambiguity, we give the most probable type with a flag. All this will lead to construction of a confident sample of optical counterparts of extragalactic objects of IRAS PSC/FSC: galaxies and quasars. We also will study IR/opt flux ratios, which may serve as one more characteristic to reveal galaxies with very high SFR. We will carry out calculation of IR luminosities for all IR galaxies. We expect revelation of many new ULIRGs and HLIRGs and building their largest samples.

“…BIG objects have been studied spectroscopically using BAO 2.6 m (Mickaelian et al, 2003, Sargsyan and, Special Astrophysical Observatory (SAO, Russia) 6 m (Mickaelian et al, 1998, Balayan et al, 2001, Observatoire de Haute-Provence (OHP, France) 1.93 m (Mickaelian, 2004) telescopes and the Sloan Digital Sky Survey (Abolfathi et al, 2018) (Mickaelian et al, 2018). Altogether 255 BIG objects have been studied and classified.…”

Section: Introductionmentioning

confidence: 99%

Observations and Study of Byurakan-IRAS Galaxies: Summary

Mikayelyan

Mickaelian

Abrahamyan

et al. 2019

The paper is a summary and general analysis of optical spectroscopic data on 257 Byurakan-IRAS Galaxies (BIG objects) obtained with the BAO 2.6-m, SAO 6-m, OHP 1.93-m telescopes and taken from SDSS spectroscopic database. 149 star-formation regions galaxies, 42 galaxies with active nuclei, and 28 galaxies with a composite spectrum were identified. The spectra of 21 galaxies show signs of emission, but without the possibility of more precise determination of their activity type, 13 galaxies appear to have star formation rates that do not exceed normal, and 3 are absorption galaxies.