BROADBAND OBSERVATIONS OF THE COMPTON-THICK NUCLEUS OF NGC 3393

• Published in: The Astrophysical journal Vol. 807; no. 2; pp. 1 - 18
• Main Authors: Koss, Michael J., Romero-Cañizales, C., Baronchelli, L., Teng, S. H., Balokovi, M., Puccetti, S., Bauer, F. E., Arévalo, P., Assef, R., Ballantyne, D. R., Brandt, W. N., Brightman, M., Comastri, A., Gandhi, P., Harrison, F. A., Luo, B., Schawinski, K., Stern, D., Treister, E.
• Format: Journal Article
• Language: English
• Published: United Kingdom The American Astronomical Society 10.07.2015
• Subjects: Active galactic nuclei; Arrays; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; Counting; galaxies: active; galaxies: individual (NGC 3393); galaxies: Seyfert; GALAXY NUCLEI; Gaussian; Luminosity; Radio emission; Simulation; TELESCOPES; X RADIATION; X-RAY GALAXIES; X-rays; X-rays: galaxies
• ISSN: 0004-637X; 1538-4357; 1538-4357
• DOI: 10.1088/0004-637X/807/2/149

ABSTRACT We present new Nuclear Spectroscopic Telescope Array (NuSTAR ) and Chandra observations of NGC 3393, a galaxy reported to host the smallest separation dual active galactic nuclei (AGN) resolved in the X-rays. While past results suggested a 150 pc separation dual AGN, three times deeper Chandra imaging, combined with adaptive optics and radio imaging suggest a single, heavily obscured, radio-bright AGN. Using Very Large Array and Very Long Baseline Array data, we find an AGN with a two-sided jet rather than a dual AGN and that the hard X-ray, UV, optical, near-infrared, and radio emission are all from a single point source with a radius <0 2. We find that the previously reported dual AGN is most likely a spurious detection resulting from the low number of X-ray counts (<160) at 6-7 keV and Gaussian smoothing of the data on scales much smaller than the point-spread function (PSF) (0 25 versus 0 80 FWHM). We show that statistical noise in a single Chandra PSF generates spurious dual peaks of the same separation (0 55 0 07 versus 0 6) and flux ratio (39% 9% versus 32% counts) as the purported dual AGN. With NuSTAR, we measure a Compton-thick source ( ) with a large torus half-opening angle, which we postulate results from feedback from strong radio jets. This AGN shows a 2-10 keV intrinsic-to-observed flux ratio of ( versus ). Using simulations, we find that even the deepest Chandra observations would severely underestimate the intrinsic luminosity of NGC 3393 above , but would detect an unobscured AGN of this luminosity out to high redshift ( ).