BROADBAND OBSERVATIONS OF THE COMPTON-THICK NUCLEUS OF NGC 3393

作者：Koss Michael J^*; Romero Canizales C; Baronchelli L; Teng S H; Balokovic M; Puccetti S; Bauer F E; Arevalo 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

来源：Astrophysical Journal, 2015, 807(2): 149.

DOI：10.1088/0004-637X/807/2/149

• galaxies: active
• galaxies: individual (NGC 3393)
• galaxies: Seyfert
• X-rays: galaxies

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 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 (N-H = 2.2 +/- 0.4 x 10(24) cm(-2)) with a large torus half-opening angle, theta tor = 79-(+1)(19)degrees which we postulate results from feedback from strong radio jets. This AGN shows a 2-10 keV intrinsic-to-observed flux ratio of approximate to 150 (L2-10 keV int = 2.6 +/- 0.3 x 10(43) erg s(-1) versus L2-10 keV observed = 1.7 +/- 0.2 x 10(41) erg s(-1)). Using simulations, we find that even the deepest Chandra observations would severely underestimate the intrinsic luminosity of NGC 3393 above z > 0.2, but would detect an unobscured AGN of this luminosity out to high redshift (z approximate to 5).

• 出版日期2015-7-10