WITNESSING THE KEY EARLY PHASE OF QUASAR EVOLUTION: AN OBSCURED ACTIVE GALACTIC NUCLEUS PAIR IN THE INTERACTING GALAXY IRAS 20210+1121

Journal Article · Wed Oct 20 00:00:00 EDT 2010 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/722/2/L147· OSTI ID:21452742

Piconcelli, Enrico; Fiore, Fabrizio; Maiolino, Roberto; Nicastro, Fabrizio ^[1]; Vignali, Cristian ^[2]; Bianchi, Stefano ^[3]; Mathur, Smita ^[4]; Guainazzi, Matteo ^[5]; Lanzuisi, Giorgio ^[6]

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1. Osservatorio Astronomico di Roma (INAF), Via Frascati 33, I-00040 Monte Porzio Catone (Roma) (Italy)
2. Dipartimento di Astronomia, Universita di Bologna, Via Ranzani 1, I-40127 Bologna (Italy)
3. Dipartimento di Fisica, Universita degli Studi Roma Tre, via della Vasca Navale 84, I-00146 Roma (Italy)
4. Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States)
5. European Space Astronomy Centre of the European Space Agency, P.O. Box 78, Villanueva de la Canada, E-28691 Madrid (Spain)
6. IASF - INAF, via del Fosso del Cavaliere 100, I-00133 Roma (Italy)

We report the discovery of an active galactic nucleus (AGN) pair in the interacting galaxy system IRAS 20210+1121 at z = 0.056. An XMM-Newton observation reveals the presence of an obscured (N {sub H} {approx} 5 x 10{sup 23} cm{sup -2}), Seyfert-like (L {sub 2-10keV} = 4.7 x 10{sup 42} erg s{sup -1}) nucleus in the northern galaxy, which lacks unambiguous optical AGN signatures. Our spectral analysis also provides strong evidence that the IR-luminous southern galaxy hosts a Type 2 quasar embedded in a bright starburst emission. In particular, the X-ray primary continuum from the nucleus appears totally depressed in the XMM-Newton band as expected in the case of a Compton-thick absorber, and only the emission produced by Compton scattering ('reflection') of the continuum from circumnuclear matter is seen. As such, IRAS 20210+1121 seems to provide an excellent opportunity to witness a key, early phase in the quasar evolution predicted by the theoretical models of quasar activation by galaxy collisions.

• OSTI ID: 21452742
• Journal Information: Astrophysical Journal Letters, Vol. 722, Issue 2; Other Information: DOI: 10.1088/2041-8205/722/2/L147; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
COMPTON EFFECT
EMISSION
GALACTIC EVOLUTION
GALAXIES
GALAXY NUCLEI
QUASARS
STAR EVOLUTION
X RADIATION
BASIC INTERACTIONS
COSMIC RADIO SOURCES
ELASTIC SCATTERING
ELECTROMAGNETIC INTERACTIONS
ELECTROMAGNETIC RADIATION
EVOLUTION
INTERACTIONS
IONIZING RADIATIONS
RADIATIONS
SCATTERING