High-z (z > 3) QSOs studied with Subaru/HSC

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High-z (z gt 3) QSOs studied with Subaru/HSC

• Masa Imanishi (NAOJ)
• Tohru Nagao (NAOJ)

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Outline

• Importance and current understanding
• of high-z QSOs (AGNs)

2. QSOs at z gt 7
(M.Imanishi)
(Subaru/HSC UKIRT/WFCAM)
3. Low-luminosity QSOs at z 3-6
(Subaru/HSC)
(T.Nagao)
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Why High-z QSOs(AGNs) ?
(1) Very bright
MBH 106-9Msun
DLA, LyA forest
IGM properties (re-ionization)
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High-z QSO found by SDSS
gt1000 QSOs at zgt3
1um _at_z7
Bright QSOs only !
zgt7 QSO not detectable in the optical
z6.42 Most distant
Fan 2006
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Post SDSS QSO Survey
What next?
(1) Search for z gt 7 QSOs
NIR data required
(UKIRT/WFCAM)
(2) Search for lower-Luminosity QSOs at z
3-6
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1. zgt7 QSOs
filters
NIR
optical
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Y20.5,J20.0, H18.8,K18.4
UKIRT/WFCAM/LAS
zgt7 QSOs 10 expected
Northern 1907.6 deg2
Equatorial 1907.6 deg2
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No deep z-band image zgt7 QSO candidates cannot
be selected
z - J
z - J
zgt7 QSO z NIR very large
SDSS gt2 mag needed
J - K
J - K
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Y-band
WFCAM team compromise
GreenQSO
Y
z
i
RedBD
J
i - Y
Y-J color difference (small)
Severe contamination
i ,Y limiting mag differs only 2mag
Y - J
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Proposal
gt1000 deg 2(wide), zgt23.5mag (deep) survey
Possible only with Subaru/HSC
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Why Japan?
Deep, wide z-band survey only possible with HSC
Southern VISTA Zlt21.5 (?)
At z7, z-ID requires 0.9-1.5um spectroscopy
Subaru/MOIRCS can
Japan can lead this area, if we do follow-up
before HSC data become archival !
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Issues to be solved
SDSS z or Z
Y dwarf
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2. low-luminosity QSOs (z3-6)
QSO LF
bright end only at zgt3
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UV Background from QSOs at z3-6
QSO UV is hard
QSOs
Stars
Energy (Rydberg)
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QSO Correlation Func.
Faint, numerous QSOs
Corr.Func. ? bias ? M(halo) ? QSO lifetime
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Strategy
Moderately Deep and Moderately Wide QSO Surveys
SDSS too shallow Deep Surveys (UDF, SDF)
too narrow
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Survey Strategy
Multi-band Selection
g
u
r
i
z
3000 Wavelength(A) 10000
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Multi-band HSC Survey
HSC

• g r i z (3mag deeper than SDSS)

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Summary
1. QSOs at z gt 7
(Subaru/HSC UKIRT/WFCAM)
2. Low-luminosity QSOs at z 3-6
(Subaru/HSC)
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End
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QSO Environment
QSO Activity ? Interaction
Borne et al. (2000)
QSOs
Blank-field
excess
Bright galaxy number excess around QSOs
Results at z0.2 (McLure Dunlop 2001)
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Strategy
Trigger of QSO Activity Growth of SMBHs in
QSOs Relation with Galaxy Evolution
SDSS too shallow Deep Surveys (UDF, SDF)
too narrow
Luminosity Function of QSOs Correlation Function
of QSOs Environments of QSOs
Moderately Deep and Moderately Wide QSO Surveys
We need a QSO sample with wide luminosity
range with enough number density
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QSO Correlation Func.
Croom et al. (2005)
Corr.Func. ? bias ? Mhalo bias ? QSO
Lifetime mass-accretion timescale
Redshift
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Co-Evolution of SMBHs and Galaxies
Evolutionary link between SMBHs and galaxies
Every galaxies may once experienced an AGN phase
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SDSS QSO Survey Redshift Distribution
Schneider et al. (2005)
u-dropout
g-dropout
46420 QSOs in SDSS DR3
0 1 2 3
4 5 Redshift