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The 2MASS Red AGN Survey

R. Cutri, B. Nelson, D. Kirkpatrick (IPAC/Caltech) M. Skrutskie (U. Virginia) P. Francis (ANU/MSSSO) P. Smith. G. Schmidt, D. Hines (U. Arizona) J. Huchra, B. Wilkes (Harvard/Smithsonian). The 2MASS Red AGN Survey.

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The 2MASS Red AGN Survey

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  1. R. Cutri, B. Nelson, D. Kirkpatrick (IPAC/Caltech) M. Skrutskie (U. Virginia) P. Francis (ANU/MSSSO) P. Smith. G. Schmidt, D. Hines (U. Arizona) J. Huchra, B. Wilkes (Harvard/Smithsonian) The 2MASS Red AGN Survey

  2. Far-IR and Radio surveys suggest 50-80% of AGN in local universe are missed by optical/UV surveys because of dust obscuration IRAS QSOs (Low et al. 1997) Red QSOs from radio surveys (Webster et al. 1995; Francis et al. 1999) Very red, luminous, high-z FIRST/2MASS AGN (Gregg et al. 2002) May account for at least part of XRB (e.g. Comastri et al. 1995) But UV-excess/optical color-selected surveys appear to be 80-90% complete 2dF complete spectroscopic survey - 16.5<bj<19.7 (Meyer et al. 2001) SDSS QSO survey (Ivezic et al. 2002) Conduct a large-scale, uniform IR survey for reddened AGN Is There a Population of Obscured AGN?

  3. Uniform all-sky photometry of2MASS provides basis to search for and characterize a population of obscured or intrinsically red AGN 95% ofknown optical/UV/radio-selected QSOs have J-Ks < 2.0 2MASS Red AGN candidate selection 3 band detection, J-Ks > 2 |b|>30o, exclude SMC/LMC to avoid AGB stars 20,400 deg2 16,997 candidates Brightest candidates are high-latitude AGB stars <5% are known AGN Red AGN Search Criteria Histograms of J-Ks color (from 2MASS) for (top-to-bottom) PG, northern and southern Hamburg, LBQS and FIRST Bright QSO samples

  4. Spectroscopic follow-up of 704 (4.1%) candidates 69% of observed candidates are Type 1 or Type 2 AGN Remainder are starburst or normal galaxies, AGB stars and L-dwarfs ~5% unclassifiable because of low SNR Most of the AGN are Type 1 (e.g. broad-line - QSO/Sy1.x) N(type 1)/N(type 2) ~ 4 Preliminary 2MASS Search Results

  5. Color selection biases search Reddest objects missed because flux-limited sample driven by J-band Ks<12m missed because resolved Dilution by starlight makes blue Selection Biases • Redshift distribution: 0.03 < z < 2.52 • Most are low z - Median z = 0.22 • k-correction biases to low-z • Peak near J-Ks ~2.2 because H-alpha in Ks

  6. Extrapolated surface density is ~0.5 red AGN deg-2 @ Ks<14.5 Incomplete for Ks>13.5 Corresponds to QSO surface density at bj<18.2 mag (Meyer et al. 2001) Detection in other surveys 50% detected in FIRST radio survey 10% detected in Rosat Faint Src. Sur. 20% detected by IRAS Properties of the New 2MASS AGN Cumulative red AGN number counts as a function of Ks magnitude

  7. LK- Redshift Distribution Type 2 AGN lower luminosity As expected, IR survey finds highest IR-luminosity objects But some optical surveys (e.g. Hamburg/ESO) sample similar Ks-luminosity range Properties of the New 2MASS AGN • Ks luminosity function (S 1/Vmax) • Local space density of 2MASS type 1 AGN comparable to optical/UV selected QSOs at intermediate luminosities • Drop-off at highest luminosity due to redshift bias (fewer high-z objects in 2MASS sample)

  8. Relative near-IR colors of 2MASS red AGN consistent with reddening of optical/UV population Nature of the 2MASS Red AGN • Optical/near-IR colors are not consistent with simple screen extinction model • 2MASS Red AGN span very large range of blue-IR color (Bj ~ 15 to >21)

  9. Smith, Schmidt, Hines, Cutri, & Nelson (2002 ApJ, 569, 23) 2MASS AGN most strongly polarized sample of radio quiet AGN 11/89 2MASS red AGN have optical broadband P>3%, with max P=11% (no PG QSOs have P>3%) Host galaxy dilutes light in some, so %P lower limit Intermediate types (1.5-1.9) highest polarized fraction (23%) Highest degree of polarization seen in reddest objects Spectropolarimetry of two 2MASS AGN shows highly polarized broad lines Viewing obscured BLR in scattered light Polarization of 2MASS AGN

  10. Wilkes, Cutri, Hines, Nelson, Schmidt, & Smith (2001 ApJ, 564, L65) Subset of Type 1 & 2 AGN with Ks<13.8 & B-Ks > 4.3 15/26 with ACIS-I observations Exposures set to detect 1/800 x prediction based on aKX = 2.1 Chandra Observations of 2MASS AGN • 2MASS red AGN are absorbed in X-rays • All are X-ray faint • Hardness ratios - NH ~ 1021-1023 • Even after correction for internal extinction, some are still underluminous in X-rays

  11. 2MASS is revealing large numbers of previously unknown, predominantly low redshift, red AGN >12,000 expected over the entire sky, ~70% of which will be Sy1/QSO Luminosity function implies that space density of intermediate luminosity Type 1 2MASS AGN may be comparable to optical/UV-selected QSOs Under-represented in optical/UV searches because too faint in blue/UV (e.g. Francis, Whiting and Webster 2000) NIR colors, source counts, polarization properties and X-ray flux and slopes suggest that many 2MASS AGN are red because of obscuration But geometry and distribution of dust, origin of continuum at different wavelengths complicates interpretation Red AGN may be underluminous in X-rays Implications for modeling AGN contribution of X-ray background Summary

  12. Highly uniform digital imaging survey of the entire sky in three near IR bands Identical, dedicated 1.3m telescopes at Mt. Hopkins and CTIO Three NICMOS 3 arrays for simultaneous imaging in J(1.25mm) H(1.65mm) and Ks(2.17mm) Data Products Calibrated Image Atlas (~4e6 512x1024 1”/pix FITS images in the 3 survey bands) Point Source Catalog (astrometry and photometry for ~3.5e8 point sources) SNR=10:1 at ~1mJy (J<15.8, H<15.1 Ks<14.3), positional accuracy <0.3" RMS wrt ICRS Extended Source Catalog (positions and photometry for ~2e6 resolved sources, mostly galaxies) SNR=10:1 at ~4mJy (J<15.0, H<14.6, Ks<13.5) Survey Status 100% of the sky observed (Feb 2001) Data products covering 48% of the sky now in public domain Final data processing of full data set completed Feb 2002, Catalog generation and validation in progress Full-sky data release in Sept 2002 2MASS Overview All-sky JHKs composite point source surface density map

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