Q2122-444: A NAKED ACTIVE GALACTIC NUCLEUS FULLY DRESSED
- George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States)
- Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-INAF), via del Fosso del Cavaliere 100, I-00133 Roma (Italy)
- Dipartimento di Fisica, Universita degli Studi Roma Tre, via della Vasca Navale 84, I-00146 Roma (Italy)
- ESO-European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Santiago 19 (Chile)
- INAF-Osservatorio Astronomico di Brera, via E. Bianchi 46, I-23807 Merate (Italy)
- Australia Telescope National Facility, CSIRO, P.O. Box 76, Epping, NSW 1710 (Australia)
- NASA Goddard Space Flight Center, Code 661, Greenbelt, MD 20771 (United States)
Based on previous spectral and temporal optical studies, Q2122-444 has been classified as a naked active galactic nucleus (AGN) or true type 2 AGN, that is, an AGN that genuinely lacks a broad-line region (BLR). Its optical spectrum seemed to possess only narrow forbidden emission lines that are typical of type 2 (obscured) AGNs, but the long-term optical light curve, obtained from a monitoring campaign over more than two decades, showed strong variability, apparently ruling out the presence of heavy obscuration. Here we present the results from a {approx}40 ks XMM-Newton observation of Q2122-444 carried out to shed light on the energetics of this enigmatic AGN. The X-ray analysis was complemented with Australia Telescope Compact Array radio data to assess the possible presence of a jet, and with new NTT/EFOSC2 optical spectroscopic data to verify the actual absence of a BLR. The higher-quality optical data revealed the presence of strong and broad Balmer lines that are at odds with the previous spectral classification of this AGN. The lack of detection of radio emission rules out the presence of a jet. The X-ray data combined with simultaneous UV observations carried out by the Optical Monitor (OM) aboard XMM-Newton confirm that Q2122-444 is a typical type 1 AGN without any significant intrinsic absorption. New estimates of the black hole mass independently obtained from the broad Balmer lines and from a new scaling technique based on X-ray spectral data suggest that Q2122-444 is accreting at a relatively high rate in Eddington units.
- OSTI ID:
- 21476663
- Journal Information:
- Astrophysical Journal, Vol. 725, Issue 2; Other Information: DOI: 10.1088/0004-637X/725/2/2071; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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