LeMMINGs - IV. The X-ray properties of a statistically complete sample of the nuclei in active and inactive galaxies from the Palomar sample
Journal article, 2022

All 280 of the statistically complete Palomar sample of nearby ( < 120 Mpc) galaxies δ> 20 ◦have been observed at 1.5 GHz as part of the LeMMINGs e -MERLIN le gac y surv e y. Here, we present Chandr a X-ray observations of the nuclei of 213 of these galaxies, including a statistically complete sub-set of 113 galaxies in the declination range 40 ◦<δ< 65 ◦. We observed galaxies of all optical spectral types, including 'active' galaxies [e.g. low-ionization nuclear emission line regions (LINERs) and Seyferts] and 'inactive' galaxies like H II galaxies and absorption line galaxies (ALG). The X-ray flux limit of our surv e y is 1.65 ×10 -14 erg s -1 cm -2 (0.3 -10 keV). We detect X-ray emission coincident within 2 arcsec of the nucleus in 150/213 galaxies, including 13/14 Seyferts, 68/77 LINERs, 13/22 ALGs and 56/100 H II galaxies, but cannot completely rule out contamination from non-AGN processes in sources with nuclear luminosities ≲ 10 39 erg s -1 . We construct an X-ray Luminosity function (XLF) and find that the local galaxy XLF, when including all active galactic nucleus (AGN) types, can be represented as a single power law of slope -0.54 ±0.06. The Eddington ratio of the Seyferts is usually 2 -4 decades higher than that of the LINERs, ALGs, and H II galaxies, which are mostly detected with Eddington ratios ≲ 10 -3 . Using [ O III ] line measurements and black hole masses from the literature, we show that LINERs, H II galaxies and ALGs follow similar correlations to low luminosities, suggesting that some 'inactive' galaxies may harbour AGN.

X-rays: Galaxies

Galaxies: Active


D. R.A. Williams

University of Southampton

University of Manchester

University of Oxford

M. Pahari

University of Southampton

IIT Hyderabad

R. D. Baldi

Istituto di Radioastronomia

University of Southampton

I. M. McHardy

University of Southampton

S. Mathur

Ohio State University

Eureka Scientific

R. J. Beswick

University of Manchester

A. Beri

University of Southampton

Indian Institute of Science

P. Boorman

Czech Academy of Sciences

Susanne Aalto

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

Antxon Alberdi

Institute of Astrophysics of Andalusia (IAA)

M. K. Argo

University of Central Lancashire

B. T. Dullo

Complutense University

D. M. Fenech

University of Cambridge

D. A. Green

University of Cambridge

J. H. Knapen

University of La Laguna

Instituto de Astrofísica de Canarias

Ivan Marti-Vidal

Universitat de Valencia

J. Moldon

Institute of Astrophysics of Andalusia (IAA)

University of Manchester

C. G. Mundell

University of Bath

T. Muxlow

University of Manchester

F. Panessa

Istituto nazionale di astrofisica (INAF)

M.A. Pérez-Torres

Institute of Astrophysics of Andalusia (IAA)

P. Saikia

New York University Abu Dhabi

F. Shankar

University of Southampton

I. R. Stevens

University of Birmingham

P. Uttley

Anton Pannekoek Institute for Astronomy

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 510 4 4909-4928

Subject Categories

Subatomic Physics

Astronomy, Astrophysics and Cosmology

Atom and Molecular Physics and Optics



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3/3/2022 4