Universität zu Köln

Zajacek, Michal ORCID: 0000-0001-6450-1187, Busch, Gerold, Valencia-S, Monica, Eckart, Andreas, Britzen, Silke, Fuhrmann, Lars, Schneeloch, Jana, Fazeli, Nastaran, Harrington, Kevin C. and Zensus, J. Anton (2019). Radio spectral index distribution of SDSS-FIRST sources across optical diagnostic diagrams. Astron. Astrophys., 630. LES ULIS CEDEX A: EDP SCIENCES S A. ISSN 1432-0746

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Abstract

Context. The empirical relations between supermassive black holes and their host spheroids point towards the crucial role of galactic nuclei in affecting the properties of their hosts. A detailed understanding of how the activity of a galactic nucleus regulates the growth of its host is still missing. Aims. To understand the activity and the types of accretion of supermassive black holes in different hosts, it is essential to study the radio-optical properties of a large sample of extragalactic sources. In particular, we aim to study the radio spectral index trends across the optical emission line diagnostic diagrams to search for potential (anti)correlations. Methods. To this goal, we combined flux densities from the radio FIRST survey at 1.4 GHz (with the flux density range 10 mJy <= F-1.4 <= 100 mJy) for 396 SDSS sources at intermediate redshift (0.04 <= z <= 0.4) with the Effelsberg radiotelescope measurements at 4.85 GHz and 10.45 GHz. The information about the optical emission-line ratios is obtained from the SDSS-DR7 catalogue. Results. Using the Effelsberg data, we were able to infer the two-point radio spectral index distributions for star-forming galaxies, composite galaxies (with a combined contribution to the line emission from the star formation and AGN activity), Seyferts, and low ionization narrow emission region (LINER) galaxies. Conclusions. While studying the distribution of steep, flat, and inverted sources across optical diagnostic diagrams, we found three distinct classes of radio emitters for our sample: (i) sources with a steep radio index, high ionization ratio, and high radio loudness, (ii) sources with a flat radio index, lower ionization ratio, and intermediate radio loudness, (iii) sources with an inverted radio index, low ionization ratio, and low radio loudness. The classes (i), (ii), and (iii) cluster mainly along the transition from Seyfert to LINER sources in the optical diagnostic (Baldwin, Phillips & Telervich; BPT) diagram. We interpret these groups as a result of the recurrent nuclear-jet activity.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Zajacek, Michal UNSPECIFIED orcid.org/0000-0001-6450-1187 UNSPECIFIED Busch, Gerold UNSPECIFIED UNSPECIFIED UNSPECIFIED Valencia-S, Monica UNSPECIFIED UNSPECIFIED UNSPECIFIED Eckart, Andreas UNSPECIFIED UNSPECIFIED UNSPECIFIED Britzen, Silke UNSPECIFIED UNSPECIFIED UNSPECIFIED Fuhrmann, Lars UNSPECIFIED UNSPECIFIED UNSPECIFIED Schneeloch, Jana UNSPECIFIED UNSPECIFIED UNSPECIFIED Fazeli, Nastaran UNSPECIFIED UNSPECIFIED UNSPECIFIED Harrington, Kevin C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Zensus, J. Anton UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-133716
DOI:	10.1051/0004-6361/201833388
Journal or Publication Title:	Astron. Astrophys.
Volume:	630
Date:	2019
Publisher:	EDP SCIENCES S A
Place of Publication:	LES ULIS CEDEX A
ISSN:	1432-0746
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Physics > Institute of Physics I
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language DIGITAL SKY SURVEY; ACTIVE GALACTIC NUCLEI; PRESSURE-DOMINATED PHOTOIONIZATION; SUPERMASSIVE BLACK-HOLES; EMISSION-LINE SPECTRA; STAR-FORMATION; HOST GALAXIES; COMPLETE SAMPLE; 1ST SURVEY; AGN Multiple languages Astronomy & Astrophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/13371