The%20Atomic%20and%20Molecular%20Environments%20of%20AGN

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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

• Also detected in absorption on
• one EVN baseline

• Absorption appears only toward
• counterjet

• First scientific observation
• processed at the new JIVE
• correlator

image courtesy Ylva Pihlstroem
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NGC 4258

• Considered best evidence of
• a supermassive black hole

• Can estimate central mass

• Can estimate distance to
• host galaxy

For recent work, see Humphreys talk Thursday and
Modjaz poster 26
image courtesy Lincoln Greenhill (see Miyoshi et
al 1995 Herrnstein et al 1999)
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Environment of AGNs
(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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HI absorption Hydra A

• Optical Depth 0.8
• FWHM 80 km/s
• NH 1 x 1024 cm-2
• for Tspin 8000 K
• Mass 2 x 107 Msun
• for r50 pc

(Taylor 1996)
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HI absorption 2322-123

• Optical depth 0.26
• FWHM 735 km/s
• Column density
• NH 3 x 1024 cm-2
• for Tspin 8000 K
• Mass
• 109 Msun for r50 pc

(Taylor et al 2000)
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HI absorption 1946708

• Optical depth 0.2
• FWHM 350 km/s
• NH 3 x 1023 cm-2 for Tspin 8000
  K
• Mass 108 Msun

(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 HI Absorption
See Taylor poster 35
(Peck 1999)
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OH in IIIZw35

• Masers lie in a ring of radius
• r22pc

• Velocity field confirms rotation

• Absorption lies outside maser
• ring

(Pihlstroem et al 2001)
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NGC 1275
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Free-Free Absorption 1946708

• Spectral index map using 1.3 Global VLBI and 5
  GHz VLBA observations
• free-free optical depth
• tff T-3/2 ne2 n-2 d
• Ne 3 x 1022 cm-2
• ionization 10

More free-free results Kameno talk
(Peck Taylor 2001)
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Polarization and Faraday Rotation
3C279
Source Screen Observer
(Zavala Taylor 2003)
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All regions detected
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HI absorption -- NGC 7674
Future Possibilities -- Sensitivity

• VLBA Y27 Arecibo

• Beam17 x 5 mas, PA 3o
• Cont. rms noise 30 mJy/beam
• Line rms noise 260 mJy/beam

Momjian et al 2002
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Future Possibilities

• Phase Referencing
• more calibrators
• (talks on Wed afternoon, Thurs morning)
• Weaker masers more H2O jet masers and
  kilomasers
• OH Megamasers (Darling, Pihlstroem today
  after coffee)
• Higher frequency lines
• (SMA testing currently gt20 science
  observations)