Green bank telescope observations of the water masers of NGC 3079: Accretion disk magnetic field and maser scintillation
We present observations of the 22 GHz H2O megamasers in the circumnuclear disk of NGC 3079 obtained with the Green Bank Telescope. The data are analyzed for circular polarization due to the Zeeman-induced splitting of the H2O maser lines. No circular polarization is detected, and we derive a 1 upper...
| Main Authors: | , , |
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| Format: | Journal Article |
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The American Astronomical Society
2007
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| Online Access: | http://hdl.handle.net/20.500.11937/27844 |
| _version_ | 1848752376103567360 |
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| author | Vlemmings, Wouter Bignall, Hayley Diamond, Phil |
| author_facet | Vlemmings, Wouter Bignall, Hayley Diamond, Phil |
| author_sort | Vlemmings, Wouter |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | We present observations of the 22 GHz H2O megamasers in the circumnuclear disk of NGC 3079 obtained with the Green Bank Telescope. The data are analyzed for circular polarization due to the Zeeman-induced splitting of the H2O maser lines. No circular polarization is detected, and we derive a 1 upper limit of 11 mG for the toroidal magnetic field at 0.64 pc from the central black hole. This is the tightest upper limit for the magnetic field around a black hole to date. We use the magnetic field limit to derive an estimate of the mass accretion onto the central black hole. In addition to the polarimetric results, we present an observation of rapid variability in the maser lines, which we explain as weak interstellar scintillation. From the scintillation parameters, we estimate an intrinsic size of the mostly saturated maser features of 12 as. This is consistent with models assuming a thick, clumpy accretion disk. |
| first_indexed | 2025-11-14T08:07:38Z |
| format | Journal Article |
| id | curtin-20.500.11937-27844 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T08:07:38Z |
| publishDate | 2007 |
| publisher | The American Astronomical Society |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-278442023-02-22T06:24:24Z Green bank telescope observations of the water masers of NGC 3079: Accretion disk magnetic field and maser scintillation Vlemmings, Wouter Bignall, Hayley Diamond, Phil galaxies: individual (NGC 3079) scattering masers magnetic fields We present observations of the 22 GHz H2O megamasers in the circumnuclear disk of NGC 3079 obtained with the Green Bank Telescope. The data are analyzed for circular polarization due to the Zeeman-induced splitting of the H2O maser lines. No circular polarization is detected, and we derive a 1 upper limit of 11 mG for the toroidal magnetic field at 0.64 pc from the central black hole. This is the tightest upper limit for the magnetic field around a black hole to date. We use the magnetic field limit to derive an estimate of the mass accretion onto the central black hole. In addition to the polarimetric results, we present an observation of rapid variability in the maser lines, which we explain as weak interstellar scintillation. From the scintillation parameters, we estimate an intrinsic size of the mostly saturated maser features of 12 as. This is consistent with models assuming a thick, clumpy accretion disk. 2007 Journal Article http://hdl.handle.net/20.500.11937/27844 10.1086/510515 The American Astronomical Society unknown |
| spellingShingle | galaxies: individual (NGC 3079) scattering masers magnetic fields Vlemmings, Wouter Bignall, Hayley Diamond, Phil Green bank telescope observations of the water masers of NGC 3079: Accretion disk magnetic field and maser scintillation |
| title | Green bank telescope observations of the water masers of NGC 3079: Accretion disk magnetic field and maser scintillation |
| title_full | Green bank telescope observations of the water masers of NGC 3079: Accretion disk magnetic field and maser scintillation |
| title_fullStr | Green bank telescope observations of the water masers of NGC 3079: Accretion disk magnetic field and maser scintillation |
| title_full_unstemmed | Green bank telescope observations of the water masers of NGC 3079: Accretion disk magnetic field and maser scintillation |
| title_short | Green bank telescope observations of the water masers of NGC 3079: Accretion disk magnetic field and maser scintillation |
| title_sort | green bank telescope observations of the water masers of ngc 3079: accretion disk magnetic field and maser scintillation |
| topic | galaxies: individual (NGC 3079) scattering masers magnetic fields |
| url | http://hdl.handle.net/20.500.11937/27844 |