Chandra Observations of Candidate "True" Seyfert 2 Nuclei
| dc.creator | Ghosh, Himel | |
| dc.creator | Pogge, Richard W. | |
| dc.creator | Mathur, Smita | |
| dc.creator | Martini, Paul | |
| dc.creator | Shields, Joseph C. | |
| dc.date | 2006-06-20 | |
| dc.date.accessioned | 2026-07-07T10:39:19Z | |
| dc.date.available | 2026-07-07T10:39:19Z | |
| dc.description | The Unification Model for active galactic nuclei posits that Seyfert 2s are intrinsically like Seyfert 1s, but that their broad-line regions (BLRs) are hidden from our view. A Seyfert 2 nucleus that truly lacked a BLR, instead of simply having it hidden, would be a so-called "true" Seyfert 2. No object has as yet been conclusively proven to be one. We present a detailed analysis of four of the best "true" Seyfert 2 candidates discovered to date: IC 3639, NGC 3982, NGC 5283, and NGC 5427. None of the four has a broad H-alpha emission line, either in direct or polarized light. All four have rich, high-excitation spectra, blue continua, and Hubble Space Telescope (HST) images showing them to be unresolved sources with no host-galaxy obscuration. To check for possible obscuration on scales smaller than that resolvable by HST, we obtained X-ray observations using the Chandra X-ray Observatory. All four objects show evidence of obscuration and therefore could have hidden BLRs. The picture that emerges is of moderate to high, but not necessarily Compton-thick, obscuration of the nucleus, with extra-nuclear soft emission extended on the hundreds-of-parsecs scale that may originate in the narrow-line region. Since the extended soft emission compensates, in part, for the nuclear soft emission lost to absorption, both absorption and luminosity are likely to be severely underestimated unless the X-ray spectrum is of sufficient quality to distinguish the two components. This is of special concern where the source is too faint to produce a large number of counts, or where the source is too far away to resolve the extended soft X-ray emitting region. | |
| dc.description | 26 pages, 12 figures, submitted to ApJ | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0606461 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0606461 | |
| dc.identifier | Astrophys.J.656:105-115,2007 | |
| dc.identifier | doi:10.1086/510421 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/180987 | |
| dc.subject | Astrophysics | |
| dc.title | Chandra Observations of Candidate "True" Seyfert 2 Nuclei | |
| dc.type | text |