Bibcode
Williams, D. R. A.; Pahari, M.; Baldi, R. D.; McHardy, I. M.; Mathur, S.; Beswick, R. J.; Beri, A.; Boorman, P.; Aalto, S.; Alberdi, A.; Argo, M. K.; Dullo, B. T.; Fenech, D. M.; Green, D. A.; Knapen, J. H.; Martí-Vidal, I.; Moldon, J.; Mundell, C. G.; Muxlow, T. W. B.; Panessa, F.; Pérez-Torres, M.; Saikia, P.; Shankar, F.; Stevens, I. R.; Uttley, P.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society
Advertised on:
3
2022
Citations
14
Refereed citations
10
Description
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 legacy survey. Here, we present Chandra 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 ${\rm H\, \small {II}}$ galaxies and absorption line galaxies (ALG). The X-ray flux limit of our survey 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 ${\rm H\, \small {II}}$ galaxies, but cannot completely rule out contamination from non-AGN processes in sources with nuclear luminosities $\lesssim 10^{39}$ 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 ${\rm H\, \small {II}}$ galaxies, which are mostly detected with Eddington ratios $\lesssim 10^{-3}$. Using [${\rm O\, \small {III}}$] line measurements and black hole masses from the literature, we show that LINERs, ${\rm H\, \small {II}}$ galaxies and ALGs follow similar correlations to low luminosities, suggesting that some 'inactive' galaxies may harbour AGN.
Related projects
Spiral Galaxies: Evolution and Consequences
Our small group is well known and respected internationally for our innovative and important work on various aspects of the structure and evolution of nearby spiral galaxies. We primarily use observations at various wavelengths, exploiting synergies that allow us to answer the most pertinent questions relating to what the main properties of
Johan Hendrik
Knapen Koelstra