Hot-dust-poor type 1 active galactic nuclei in the COSMOS survey

Heng Hao, Martin Elvis, Francesca Civano, Giorgio Lanzuisi, Marcella Brusa, Elisabeta Lusso, Gianni Zamorani, Andrea Comastri, Angela Bongiorno, Christopher D Impey, Anton M. Koekemoer, Emeric Le Floc'h, Mara Salvato, David Sanders, Jonathan R. Trump, Cristian Vignali

Research output: Contribution to journalArticle

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Abstract

We report a sizable class of type 1 active galactic nuclei (AGNs) with unusually weak near-infrared (1-3μm) emission in the XMM-COSMOS type 1 AGN sample. The fraction of these "hot-dust-poor" AGNs increases with redshift from 6%at lowredshift (z < 2) to 20% at moderate high redshift (2 < z < 3.5). There is no clear trend of the fraction with other parameters: bolometric luminosity, Eddington ratio, black hole mass, and X-ray luminosity. The 3μm emission relative to the 1μmemission is a factor of 2-4 smaller than the typical Elvis et al.AGNspectral energy distribution (SED), which indicates a "torus" covering factor of 2%-29%, a factor of 3-40 smaller than required by unified models. The weak hot dust emission seems to expose an extension of the accretion disk continuum in some of the source SEDs. We estimate the outer edge of their accretion disks to lie at (0.3-2.0) × 104 Schwarzschild radii, ∼10-23 times the gravitational stability radii. Formation scenarios for these sources are discussed.

Original languageEnglish (US)
JournalAstrophysical Journal Letters
Volume724
Issue number1 PART 2
DOIs
StatePublished - Nov 20 2010

Fingerprint

active galactic nuclei
dust
accretion disks
accretion
luminosity
radii
XMM-Newton telescope
near infrared
energy distribution
coverings
continuums
trends
estimates
energy
COSMOS
x rays
parameter
distribution
trend

Keywords

  • Galaxies: evolution
  • Quasars: general

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Hao, H., Elvis, M., Civano, F., Lanzuisi, G., Brusa, M., Lusso, E., ... Vignali, C. (2010). Hot-dust-poor type 1 active galactic nuclei in the COSMOS survey. Astrophysical Journal Letters, 724(1 PART 2). https://doi.org/10.1088/2041-8205/724/1/L59

Hot-dust-poor type 1 active galactic nuclei in the COSMOS survey. / Hao, Heng; Elvis, Martin; Civano, Francesca; Lanzuisi, Giorgio; Brusa, Marcella; Lusso, Elisabeta; Zamorani, Gianni; Comastri, Andrea; Bongiorno, Angela; Impey, Christopher D; Koekemoer, Anton M.; Le Floc'h, Emeric; Salvato, Mara; Sanders, David; Trump, Jonathan R.; Vignali, Cristian.

In: Astrophysical Journal Letters, Vol. 724, No. 1 PART 2, 20.11.2010.

Research output: Contribution to journalArticle

Hao, H, Elvis, M, Civano, F, Lanzuisi, G, Brusa, M, Lusso, E, Zamorani, G, Comastri, A, Bongiorno, A, Impey, CD, Koekemoer, AM, Le Floc'h, E, Salvato, M, Sanders, D, Trump, JR & Vignali, C 2010, 'Hot-dust-poor type 1 active galactic nuclei in the COSMOS survey', Astrophysical Journal Letters, vol. 724, no. 1 PART 2. https://doi.org/10.1088/2041-8205/724/1/L59
Hao H, Elvis M, Civano F, Lanzuisi G, Brusa M, Lusso E et al. Hot-dust-poor type 1 active galactic nuclei in the COSMOS survey. Astrophysical Journal Letters. 2010 Nov 20;724(1 PART 2). https://doi.org/10.1088/2041-8205/724/1/L59
Hao, Heng ; Elvis, Martin ; Civano, Francesca ; Lanzuisi, Giorgio ; Brusa, Marcella ; Lusso, Elisabeta ; Zamorani, Gianni ; Comastri, Andrea ; Bongiorno, Angela ; Impey, Christopher D ; Koekemoer, Anton M. ; Le Floc'h, Emeric ; Salvato, Mara ; Sanders, David ; Trump, Jonathan R. ; Vignali, Cristian. / Hot-dust-poor type 1 active galactic nuclei in the COSMOS survey. In: Astrophysical Journal Letters. 2010 ; Vol. 724, No. 1 PART 2.
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