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2MASS Selected AGN with 6dF

2MASS Selected AGN with 6dF. Paul Francis (ANU) Roc Cutri, Brant Nelson (IPAC/CALTECH). The Reddest 2MASS Sources. A good way to find AGN?. Ridiculously simple selection: J-K>2, from 2MASS. Greater than 60% efficiency in finding AGN - as good as UVX.

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2MASS Selected AGN with 6dF

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  1. 2MASS Selected AGN with 6dF Paul Francis (ANU) Roc Cutri, Brant Nelson (IPAC/CALTECH) 6dF Workshop, April 2005

  2. The Reddest 2MASS Sources 6dF Workshop, April 2005

  3. A good way to find AGN? • Ridiculously simple selection: J-K>2, from 2MASS. • Greater than 60% efficiency in finding AGN - as good as UVX. • AGN not detectable with any other method. • Mostly low redshifts <z> ~ 0.2 6dF Workshop, April 2005

  4. Average spectrum 6dF Workshop, April 2005

  5. Incomplete • Only have spectra of 700 of the ~ 17,000 2MASS sources with J-K>2. • Biassed sub-sets only: • Brighter than K=14: 80% are AGN: mostly Type-1 (broad-line) AGN. • But does this hold for the fainter ones? 6dF Workshop, April 2005

  6. 6dF: Very red population to fainter magnitudes. 6dF Workshop, April 2005

  7. 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. 6dF Workshop, April 2005

  8. Quality 4/3: 44 AGN out of 100 6dF Workshop, April 2005

  9. Broad-line 6dF Workshop, April 2005

  10. Narrow-line AGN 6dF Workshop, April 2005

  11. Quality 2: 7 AGN out of 50, with wrong redshifts. 6dF Workshop, April 2005

  12. 6dF Workshop, April 2005

  13. Quality 1: only ~4/120 are AGN 6dF Workshop, April 2005

  14. 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, 6dF Workshop, April 2005

  15. A wierdo! 800 km/s 6dF Workshop, April 2005

  16. Diagnostic Diagrams 6dF Workshop, April 2005

  17. Bj=20.5, absolute magnitude -9.5 6dF Workshop, April 2005

  18. Metal-poor Blue Compact Dwarf? 6dF Workshop, April 2005

  19. 6dF Workshop, April 2005

  20. 6dF Workshop, April 2005

  21. Conclusions • Around 20% of 2MASS sources with J-K>2 and K>14 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-K>2 in 2MASS. 6dF Workshop, April 2005

  22. 2dF • Used 2dF to get spectra of all 2MASS sources with J-K>1.2 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. 6dF Workshop, April 2005

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