Active Galactic Nuclei

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Active Galactic Nuclei In GOYA
Vicki Sarajedini University of Florida

• Some interesting questions
• How does the faint end of the AGN LF evolve
  beyond z1?
• How do AGN fit in as a phase of galaxy evolution?
  
• What is the nature of X-ray/Mid-IR sources?

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Multi-wavelength/multi-technique surveys are
essential to identify and study AGN at a range of
luminosities extending to redshifts beyond z1
Spectroscopic - AGN must dominate galaxy. Allows
for Type 1/2 classification plus z. Necessary
emission lines must be in wavelength range. Color
- AGN must dominate galaxy. Can detect AGN
extending to high z. Variability - Detects
primarily Type 1 AGN at a range of luminosities
and AGN/host galaxy flux ratios. X-ray - Detects
AGN at a broad range of redshifts, including
highly obscurred sources. Mid-IR - Detects
reprocessed emission in highly obscurred AGN at a
range of redshifts.
GOYA spectroscopy will provide redshifts, AGN
confirmation and classification at zgt1
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Optical Spectroscopic Surveys for AGN - Groth
Strip
DEEP1 Survey Keck (LRIS) spectroscopy and HST
images to study the formation and evolution of
distant field galaxies

• 800 spectra acquired for the Groth Strip between
  1995 and 2001
• 65,000 additional galaxies being targeted in the
  EGS with DEIMOS for DEEP2 survey

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Summary of Optical Spectroscopic detected AGN

• 5 Broad-Line AGNs (MgII (?2800Å), H balmer) -
  Type 1

• 3 with NeV emission (?3426Å) - high ionization
  line only seen in AGN (Type 1 2)
• 2 with broadened (gt400 km/s) OIII (?5007Å) -
  Type 2 AGN

• NLAGNs (Type 2) detected at 0.15ltzlt0.9
• BLAGNs (Type 1) detected at 0.65ltzlt1.3
• AGNs make up 6.5 of all GSS galaxies
• 40 of spectroscopic AGNs are also detected in
  X-rays

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Extending Spectroscopic Surveys to the Infrared

• Optical spectroscopic surveys miss many of the
  important emission lines necessary to identify
  zgt1 AGN.
• Near-IR redshift surveys (GTC and GOYA) can
  remedy this.

• Example 5 X-ray sources with no optical
  spectroscopic classification.
• Subaru telescope/CISCO spectrograph with OH
  suppression mask detected broad H? in 4 of the 5
  galaxies.

Miyaji, Sarajedini, Griffiths, Yamada, Schurch,
Cristóbal-Hornillos, Motohara (2004)
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Variability Surveys for AGN in Deep HST Fields

• Variability can be used to detect AGN on
  timescales of months to several years
• 2.5 of galaxy nuclei in GSS are significant
  variables over 6 years. The majority are likely
  to be AGN.
• 27 of the variables are X-ray detected.

• Many are too faint for optical spectroscopic
  follow-up or are failed zs. Some have
  photometric zs between 1.2 and 1.6.

?GOYA
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The Nature of X-ray detected AGN

• Unobscured AGN primarily Type 1 at z0-5
• Obscured AGN with clear optical signature Both
  Type 1 and 2 at z lt 1.5
• X-ray bright, optically normal galaxies (XBONGs).
  Galaxies at zlt1 with moderate AGN activity but no
  optical AGN spectroscopic signature
• Optically faint X-ray Sources (black dots)
  probably obscured AGN at z1-4

0 ltzlt0.5 0.5ltzlt 1 1 ltzlt 2 2 ltzlt 6
Brandt Hasinger (2005)
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