Discovery of a new QSO Discovery of a new QSO z=5.96 with the Subaru telescope z=5.96 with the Subaru telescope Tomo Goto (Japan Aerospace Exploration Agency) Tomo Goto (Japan Aerospace Exploration Agency)
Why high- -z z QSOs QSOs are important? are important? Why high 1. Directory prove re Directory prove re- -ionization of the Universe ionization of the Universe 1. 2. QSO/AGN evolution QSO/AGN evolution 2. 3. Formation of super massive black holes Formation of super massive black holes 3.
Reionization of the Universe of the Universe Reionization When and how our Universe started? ( Jelle Ritzerveld & Rien van de Weijgaert & Vincent Icke)
Visualizations of the Geometry of Reionization Visualizations of the Geometry of Reionization Garrelt Mellema.
Reionization through QSO through QSO Reionization 電離領域 Galaxies are too faint. GRBs disappear too quickly.
Why high- -z z QSOs QSOs are important? are important? Why high 1. Directory prove re Directory prove re- -ionization of the Universe ionization of the Universe 1. 2. QSO/AGN evolution QSO/AGN evolution 2. 3. Formation of super massive black holes Formation of super massive black holes 3.
Systematic flattening of the LF above z~3 Systematic flattening of the LF above z~3 Fainter QSOs QSOs at z>5 are needed at z>5 are needed Fainter to investigate the evolution of QSO LF to investigate the evolution of QSO LF
Comoving number number Comoving LF slope increases at LF slope increases at density peaks between density peaks between z =3 and above. =3 and above. z z =2 and 3 =2 and 3 z
A crucial question: the shape and slope A crucial question: the shape and slope of the LF at the faint end… … of the LF at the faint end 5645 quasars with g g 5645 quasars with < 21.85 selected < 21.85 selected from SDSS imaging, from SDSS imaging, observed with 2dF observed with 2dF at AAT. UV excess at AAT. UV excess sources, almost all sources, almost all with with z z < 2.5. Best < 2.5. Best- -fit fit slope β β is slope is - -1.45 at 1.45 at faint end. faint end. Fitting these data Fitting these data simultaneously is a simultaneously is a challenge for challenge for modern models of modern models of quasar evolution. quasar evolution. Fainter QSOs QSOs at high at high- -z are needed to investigate z are needed to investigate Fainter Richards et al. 2005a MNRAS the evolution of QSO LF the evolution of QSO LF
Why high- -z z QSOs QSOs are important? are important? Why high 1. Directory prove re Directory prove re- -ionization of the Universe ionization of the Universe 1. 2. QSO/AGN evolution QSO/AGN evolution 2. 3. Formation of super massive black holes Formation of super massive black holes 3.
Constraining the formation of super Constraining the formation of super massive black holes. massive black holes. • z~ ６ QSOs are at the young Universe of 1Gyr old. • M 1450 =-27mag ： Can a black hole of billion Msun be formed in 1 Gyr? Strong constraints to the black hole formation theory （ Haiman 2006,MmSAI,77,629 ）
Are high- -z z QSOs QSOs gravitationally gravitationally lensed lensed Are high (and magnified)? (and magnified)? If yes, luminosity/mass are If yes, luminosity/mass are overestimated. overestimated.
HST ACS images are consistent with a point source. HST ACS images are consistent with a point source. Richards et al 2004,2005 ACS image of the quasar Residuals after subtracting off the PSF high- - z z QSOs QSOs do not seem to be magnified by the lens. do not seem to be magnified by the lens. high Luminosity is still ～ -27mag 27mag Luminosity is still ～ - How we form billion Msun Msun black holes in 1 black holes in 1 Gyr Gyr? ? How we form billion => Theoretical challenge. => Theoretical challenge.
Current status of high- -z QSO surveys z QSO surveys Current status of high
← Remaining flux(White et al. 2003,AJ,126 Remaining flux(White et al. 2003,AJ,126 ← ｚ =6.28 Complete Gunn- -Peterson trough Peterson trough ← Complete Gunn ← Reionization → Reionization → depends line- -of of- -sights sights depends line More QSOs QSOs in in → More → different line- -of of- -sight sight different line z=6.28 are needed to fully are needed to fully probe the reionization reionization probe the of the Universe. of the Universe. z=6.42 The resolution of these questions The resolution of these questions will have to wait for the will have to wait for the discovery of additional z>6 discovery of additional z>6 quasars. (Richard L. White) quasars. (Richard L. White) High- -z QSO surveys in the past z QSO surveys in the past High
Remaining flux in z=6.42 QSO Remaining flux in z=6.42 QSO coming from a foreground galaxy? coming from a foreground galaxy? No foreground galaxy. The flux really comes from the QSO through IGM.
Remaining flux in z=6.42 QSO Remaining flux in z=6.42 QSO coming from a foreground galaxy? coming from a foreground galaxy? No foreground galaxy. The flux really comes from the QSO through IGM.
Optical depth Optical depth Ly γ Expected density change from the expansion of the Universe. Quick change at z~5.7 ！？ We need more QSOs QSOs at z>5.7 at z>5.7 We need more
We need more ｚ＞６ ｚ＞６ QSOs QSOs. . We need more How do we search ？ → How do we search ？ →
Our strategy ： fainter 、 、 toward toward Our strategy ： fainter higher redshift redshift (z>20.2) (z>20.2) higher By product ： ： By product fainter z~5.8 fainter z~5.8 QSO, important QSO, important to investiage investiage LF LF to slope. slope.
20.2<z<21.0 still secure 20.2<z<21.0 still secure 20.2 ↓ ↓ 21.0
Method: Method: 1800 million objects to a few dozen candidates 1800 million objects to a few dozen candidates 1. -band only detections in the SDSS band only detections in the SDSS 1. ｚ - ｚ 2. Cosmic- -ray rejection ray rejection （ important ） 2. Cosmic （ important ） 3. J- -band imaging to reject brown dwarfs (brown band imaging to reject brown dwarfs (brown 3. J dwarfs are also interesting objects.) dwarfs are also interesting objects.) 4. Spectroscopy with the Subaru 4. Spectroscopy with the Subaru
The Apache Point Observatory The Apache Point Observatory Sunspot, New Mexico Sunspot, New Mexico 3.5m telescope Photometric calibration telescope 2.5m SDSS telescope
SDSS imaging camera Interior view of the camera, showing the filters on the corrector plate. Z-band filter is essential for the QSO search.
Find z- -band only band only Find z detections among 1800 detections among 1800 million objets objets in the SDSS. in the SDSS. million *TDI （ drift scan ） imaging is not particularly advantageous for QSO search.
Method: Method: 1000 million objects to a few dozen candidates 1000 million objects to a few dozen candidates 1. ｚ -band only detections in the SDSS band only detections in the SDSS ｚ - 1. 2. Cosmic Cosmic- -ray rejection ray rejection （ important ） 2. （ important ） 3. J J- -band imaging to reject brown band imaging to reject brown 3. dwarfs (brown dwarfs are also dwarfs (brown dwarfs are also interesting objects.) interesting objects.) 4. Spectroscopy with the Subaru Spectroscopy with the Subaru 4.
QSOs and brown dwarfs have the same and brown dwarfs have the same QSOs i- -z color z color → We need J- -band imaging band imaging i → We need J Telescope time Telescope time spend on spend on brown dwarfs brown dwarfs won’ ’t be t be won wasted. wasted.
z- -J can separate J can separate QSOs QSOs and brown and brown z dwarfs dwarfs J-band imaging is important.
Hard! Hard! J- -band imaging band imaging J Kitt Peak 2m telescope
Hard! Hard! J- -band imaging band imaging J UKIRT3.8m
Hard! Hard! J- -band imaging band imaging J Apach Point Observatory 3.5m
Hard! Hard! J- -band imaging band imaging J Himalayan Chandra Telescope
Hard! Hard! J- -band imaging band imaging J Okayama 1.88m
Hard! Hard! J- -band imaging band imaging J NTT3.6m
A Happy New Year @La Silla
QSO candidates QSO candidates ← good QSO candidates
i,z,J images ： a good candidate ： a good candidate i,z,J images J i z
Method: Method: 1000 million objects to a few dozen candidates 1000 million objects to a few dozen candidates 1. ｚ -band only detections in the SDSS band only detections in the SDSS 1. ｚ - 2. Cosmic Cosmic- -ray rejection ray rejection （ important ） 2. （ important ） 3. J J- -band imaging to reject brown dwarfs band imaging to reject brown dwarfs 3. (brown dwarfs are also interesting (brown dwarfs are also interesting objects.) objects.) 4. Spectroscopy with the Subaru Spectroscopy with the Subaru 4.
Subaru Subaru Feb. ２００６ ２００６ Feb.
FOCAS spectrum FOCAS spectrum We found a z=5.96 QSO We found a z=5.96 QSO Ly α + N v 、 Ly β + O vi → z=5.96 M AB,1450 = − 26.9 ( H 0 = 50 km s 1 Mpc 1 , q 0 = 0.5).
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