We present a long (≈76 ks) Chandra observation of IRAS 09104+4109, a hyperluminous galaxy, optically classified as a type 2 active galactic nuclei (AGN) hosted in a cD galaxy in a cluster at z= 0.442. We also report on the results obtained by fitting its broad-band spectral energy distribution. The Compton-thick nature of this source (which has been often referred to as an 'archetype' of Compton-thick type 2 quasars) was formerly claimed on the basis of its marginal detection in the Phoswich Detection System (PDS) instrument onboard BeppoSAX, being then disputed using XMM-Newton data. Both Chandra analysis and optical/mid-infrared (IR) spectral fitting are consistent with the presence of heavy (≈1-5 × 1023 cm-2), but not extreme (Compton-thick) obscuration. However, using the mid-IR and the [O III] emission as proxies of the nuclear hard X-ray luminosity suggests the presence of heavier obscuration. The 54-month Swift BAT map shows excess hard X-ray emission likely related to a nearby (z= 0.009) type 2 AGN, close enough to IRAS 09104+4109 to significantly enhance and contaminate its emission in the early BeppoSAX PDS data.
On the nature of the absorber in IRAS 09104+4109: the X-ray and mid-infrared view / Vignali C.; Piconcelli E.; Lanzuisi G.; Feltre A.; Feruglio C.; Maiolino R.; Fiore F.; Fritz J.; La Parola V.; Mignoli M.; Pozzi F.. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - STAMPA. - 416:(2011), pp. 2068-2077. [10.1111/j.1365-2966.2011.19181.x]
On the nature of the absorber in IRAS 09104+4109: the X-ray and mid-infrared view
VIGNALI, CRISTIAN;LANZUISI, GIORGIO;POZZI, FRANCESCA
2011
Abstract
We present a long (≈76 ks) Chandra observation of IRAS 09104+4109, a hyperluminous galaxy, optically classified as a type 2 active galactic nuclei (AGN) hosted in a cD galaxy in a cluster at z= 0.442. We also report on the results obtained by fitting its broad-band spectral energy distribution. The Compton-thick nature of this source (which has been often referred to as an 'archetype' of Compton-thick type 2 quasars) was formerly claimed on the basis of its marginal detection in the Phoswich Detection System (PDS) instrument onboard BeppoSAX, being then disputed using XMM-Newton data. Both Chandra analysis and optical/mid-infrared (IR) spectral fitting are consistent with the presence of heavy (≈1-5 × 1023 cm-2), but not extreme (Compton-thick) obscuration. However, using the mid-IR and the [O III] emission as proxies of the nuclear hard X-ray luminosity suggests the presence of heavier obscuration. The 54-month Swift BAT map shows excess hard X-ray emission likely related to a nearby (z= 0.009) type 2 AGN, close enough to IRAS 09104+4109 to significantly enhance and contaminate its emission in the early BeppoSAX PDS data.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
