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Published byKory Horton Modified over 8 years ago
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The Atomic and Molecular Environments of AGN Alison Peck SAO/SMA Project
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NGC 4261 Circumnuclear torus first seen in HST image HST image Absorption appears only toward counterjet counterjet First scientific observation processed at the new JIVE processed at the new JIVE correlator correlator Also detected in absorption on one EVN baseline one EVN baseline image courtesy Ylva Pihlstroem
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NGC 4258 image courtesy Lincoln Greenhill (see Miyoshi et al 1995 Herrnstein et al 1999) Can estimate central mass Considered best evidence of a supermassive black hole a supermassive black hole Can estimate distance to host galaxy host galaxy For recent work, see Humphreys talk Thursday and Modjaz poster 26
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Environment of AGNs Maser emission Free-free absorption Faraday Rotation HI absorption (Peck 1999)
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NGC 1052 Images courtesy Jim Braatz (See Claussen et al 1998, Braatz et al 2003)
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Mrk 348 (Peck et al 2003) (today…)
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Mrk 348 Jet Maser (Peck et al 2003)
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H I absorption Hydra A Optical Depth ~ 0.8 FWHM = 80 km/s N H = 1 x 10 24 cm -2 for T spin = 8000 K Mass ~ 2 x 10 7 M sun for r=50 pc (Taylor 1996)
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H I absorption 2322-123 Optical depth ~ 0.26 FWHM = 735 km/s Column density: N H = 3 x 10 24 cm -2 for T spin = 8000 K Mass: 10 9 M sun for r=50 pc (Taylor et al 2000)
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Optical depth ~ 0.2 FWHM = 350 km/s N H = 3 x 10 23 cm -2 for T spin = 8000 K Mass: ~ 10 8 M sun H I absorption 1946+708 (Peck & Taylor 2001)
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Not All Absorption is Associated with the AGN (Peck 1999)
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CSOs – good sources for H I Absorption (Peck 1999) See Taylor poster 35
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OH in IIIZw35 (Pihlstroem et al 2001) Masers lie in a ring of radius r~22pc r~22pc Velocity field confirms rotation Absorption lies outside maser ring ring Enclosed mass m~7x10 M 6solar
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NGC 1275
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Free-Free Absorption 1946+708 Spectral index map using 1.3 Global VLBI and 5 GHz VLBA observations free-free optical depth: ff ~ T -3/2 n e 2 -2 d N e ~ 3 x 10 22 cm -2 ionization ~ 10% (Peck & Taylor 2001) More free-free results – Kameno talk
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Polarization and Faraday Rotation Source Screen Observer (Zavala & Taylor 2003) 3C279
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All regions detected Maser emission Free-free absorption Faraday Rotation HI absorption
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H I absorption -- NGC 7674 VLBA + Y27 + Arecibo Momjian et al 2002 Beam=17 x 5 mas, PA 3 o Cont. rms noise: 30 Jy/beam Line rms noise: 260 Jy/beam 5.3 pc Future Possibilities -- Sensitivity
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Future Possibilities Phase Referencing – more calibrators (talks on Wed afternoon, Thurs morning) Weaker masers: more H 2 O jet masers and “kilomasers” OH Megamasers (Darling, Pihlstroem – today after coffee) Higher frequency lines (SMA – testing currently >20% science observations)
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