C-GOALS

• Published in: Astronomy and astrophysics (Berlin) 2018-12, Vol.620
• Main Authors: Torres-Albà, N., Iwasawa, K., Díaz-Santos, T., Charmandaris, V., Ricci, C., Chu, J. K., Sanders, D. B., Armus, L., Barcos-Muñoz, L., Evans, A. S., Howell, J. H., Inami, H., Linden, S. T., Medling, A. M., Privon, G. C., U, V., Yoon, I.
• Format: Article
• Language: English
• Subjects: Active galactic nuclei; Bolometers; Emission; Fluxes; Galaxies; galaxies: active; galaxies: starburst; Infrared astronomy; Infrared imagery; Infrared spectra; infrared: galaxies; Local group (astronomy); Luminosity; Observatories; Sky surveys (astronomy); Soft x rays; Space telescopes; Stars & galaxies; Universe; X ray telescopes; X-rays; X-rays: galaxies
• ISSN: 0004-6361; 1432-0746
• DOI: 10.1051/0004-6361/201834105

We analyze Chandra X-ray observatory data for a sample of 63 luminous infrared galaxies (LIRGs), sampling the lower-infrared luminosity range of the Great Observatories All-Sky LIRG survey (GOALS), which includes the most luminous infrared selected galaxies in the local Universe. X-rays are detected for 84 individual galaxies within the 63 systems, for which arcsecond resolution X-ray images, fluxes, infrared and X-ray luminosities, spectra and radial profiles are presented. Using X-ray and mid-infrared (MIR) selection criteria, we find AGN in (31 ± 5)% of the galaxy sample, compared to the (38 ± 6)% previously found for GOALS galaxies with higher infrared luminosities (C-GOALS I). Using MIR data, we find that (59 ± 9)% of the X-ray selected AGN in the full C-GOALS sample do not contribute significantly to the bolometric luminosity of the host galaxy. Dual AGN are detected in two systems, implying a dual AGN fraction in systems that contain at least one AGN of (29 ± 14)%, compared to the (11 ± 10)% found for the C-GOALS I sample. Through analysis of radial profiles, we derive that most sources, and almost all AGN, in the sample are compact, with half of the soft X-ray emission generated within the inner ∼1 kpc. For most galaxies, the soft X-ray sizes of the sources are comparable to those of the MIR emission. We also find that the hard X-ray faintness previously reported for the bright C-GOALS I sources is also observed in the brightest LIRGs within the sample, with LFIR > 8 × 1010 L⊙.