2MASS Selected AGN with 6dF

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2MASS Selected AGN with 6dF

• Paul Francis (ANU)
• Roc Cutri, Brant Nelson (IPAC/CALTECH)

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The Reddest 2MASS Sources
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A good way to find AGN?

• Ridiculously simple selection J-Kgt2, from 2MASS.
• Greater than 60 efficiency in finding AGN - as
  good as UVX.
• AGN not detectable with any other method.
• Mostly low redshifts ltzgt 0.2

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Average spectrum
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Incomplete

• Only have spectra of 700 of the 17,000 2MASS
  sources with J-Kgt2.
• Biassed sub-sets only
• Brighter than K14 80 are AGN mostly Type-1
  (broad-line) AGN.
• But does this hold for the fainter ones?

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6dF Very red population to fainter magnitudes.
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Status as at 2nd Data Release

• 260 sources with spectra.
• Only 100 with quality 3 4 spectra.
• 50 with quality 2 spectra,
• 120 with quality 1.

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Quality 4/3 44 AGN out of 100
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Broad-line
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Narrow-line AGN
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Quality 2 7 AGN out of 50, with wrong redshifts.
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Quality 1 only 4/120 are AGN
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Results

• AGN fraction drops dramatically for these fainter
  sources down to 20.
• The AGN themselves are very similar to those at
  brighter K-band magnitudes - ie. mainly Type-1
  median redshift 0.2.
• They are simply being swamped by a rising tide of
  moderate redshift ellipticals and edge-on spiral
  galaxies.
• 6dF Pipeline gets redshifts wrong for 20 of
  broad-line AGNs primarily those at higher
  redshifts,

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A wierdo!
800 km/s
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Diagnostic Diagrams
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Bj20.5, absolute magnitude -9.5
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Metal-poor Blue Compact Dwarf?
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Conclusions

• Around 20 of 2MASS sources with J-Kgt2 and Kgt14
  are AGN predominantly Type-1 AGN.
• These fainter red AGN are very similar to the
  brighter ones.
• Extrapolating to the whole sky, there should be
  3500 red AGNs with J-Kgt2 in 2MASS.

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2dF

• Used 2dF to get spectra of all 2MASS sources with
  J-Kgt1.2 over 12 square degrees (1200 spectra).
• AGN fraction very low - only 6.5 (though still
  much higher than in optically selected sample).
• Mostly Type-2 (narrow line) AGNs.
• What few Type-1 AGNs we found often were at
  higher redshifts.
• 50 would not be found in UVX surveys due to
  host galaxy contamination.