Warm Dust in the Most Distant Quasars

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Warm Dust in the Most Distant Quasars

• Ran Wang
• Department of Astronomy, Peking University, China

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Introduction

• Why looking for dust at z6
• The mass of dust in the earliest and most massive
  galaxies dust formation within 1 Gyr.
• The dust temperature, distribution, and
  Luminosity dust heating quasar systems.
• ? FIR luminosity ? SFR ? evolutionary stage of
  the black hole bulge system.

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Introduction
Marconi Hunt. (2002)
Tremaine et al. (2002)
MBH10-3MBulge
MBHs4
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Sample

• There are totally Thirty-three quasars discovered
  at z6.
• z5.71 to 6.43
• M_1450A lt -25.0
• Twenty-two from the SDSS survey of 8000 deg2
  area, with m1450A lt 20.
• Nine from deeper optical imaging with m1450Agt20,
  Jiang et al. 2007 Willott et al. 2007
• IR (Spitzer) optical one Cool et al. (2006)
• Radio (FIRST) optical one McGreer et al.
  (2006)

Most of these objects were optically selected
from the SDSS survey ? Represent the most
luminous quasar population at z6.
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Observations
MAMBO IRAM-30m
SHARC-II CSO
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The average FIR and radio emission
Wang et al. (2008 submitted)
FIR-millimeter spectral index 2
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Star formation in the mm non-detections

• The average FIR luminosity 1.2x1012 Lsun
• Even 50 of the FIR emission from star formation,
  the star formation rate gt 200 Msun yr-1
• The major bulge building stage via starburst has
  been finished ?

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The SEDs of millimeter detections
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The bright millimeter detections

• The FIR emission exceeds that of the local quasar
  template.
• The FIR SED is consistent with optically thin
  gray-body emission from 40 50 K dust.
• The FIR-to-radio SED is consistent with that of
  typical star forming galaxies.
• Dust mass 108 Msun
• FIR luminosity 1013 Lsun

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Luminosity correlation LFIR - LBol
Wang et al. (2008 in press)
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Luminosity correlation LFIR LCO
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Star formation in the z6 quasars

• The mm and CO detected quasars at z6
• FIR emission from 40 50 K warm dust.
• Properties similar to that of star forming
  galaxies.
• Derived star formation rate 103 Msun yr-1
• Active bulge building via massive star formation
  co-eval with SMBH accretion.

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LFIR Lya emission
Omont et al. (1996) Three kinds of spectra from
zgt4 quasars
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LFIR Lya emission
Wang et al. (2008 in press)

• Quasars at z6
• Most of the millimeter detections tend to have
  log(EW)Lya lt 1.5.
• The origin of this effect is not clear yet.
• More observations

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Summary

• We studied the (sub)millimeter emission from the
  host galaxies of quasars at z6.
• About 30 of these sources have been detected in
  warm dust continuum at 1.2 mm.
• The average FIR-to-radio SED of the non-detected
  sources is comparable to that of local optical
  quasars.
• Obvious FIR excesses in the SEDs of the strong
  millimeter detections.
• FIR dust heating dominated by Star formation at a
  rate of a few 1000 Msun yr-1 .
• The millimeter detected quasars tend to have weak
  UV line emission.

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Introduction The discovery of z6 quasars
11485251 z6.42
Bertoldi et al. (2003)
Beelen et al. 2006