1. Photoionozation & Gas outflow? Radiative cooling & Gas accretion?
A Subaru Search for Ly-alpha Blobs at High redshifts
Yuichi Matsuda (Kyoto), Toru Yamada (Tohoku), Tomoki Hayashino (Tohoku)
& the Subaru SSA22 team
1. What are Ly-alpha blobs?
Large, extended Ly-alpha nebulae recently discovered at high redshifts
(Keel et al. 1999, Steidel et al. 2000, Francis et al. 2001, Palunas et al. 2004, Matsuda et al. 2004, Nilsson et al. 2006, Saito et al. 2007, Smith&Jarvis 2007, Greve et al )
Keel et al. 1999
2. Why are they interesting?
Steidel et al. 2000
Nilsson et al. 2006
Smith & Jarvis 2007
Photoionozation & Gas outflow?
Ly-alpha blobs are related to important
processes for galaxy formation!!
Radiative cooling & Gas accretion?
(Yang et al. 2006)
Radiative cooling with Ly-alpha emission
Gas accretion into mass density peaks
through the surrounding filaments
(Mori & Umemura 2006)
Radiative & Hydro-dynamical feedback
3. Subaru search for Ly-alpha blobs at z=3
We detected ~100 Ly-alpha blobs in extended SSA22 region (1.75 deg^2) and blank fields (SDF,SXDS,GOODS, 1.25 deg^2).
Selection criteria of Lyα blobs (LAB): detection threshold=28.0mag/arcsec2
Lyα luminosity > 6 x 1042 ergs/s Lyα equivalent width > 80A
Lyα size > 16 arcsec2 (~900 kpc2)
Skymap of Ly-alpha blobs
in extended SSA22 region
Ly-alpha blobs
Ly-alpha emitters
Ly-alpha absorbers
Examples of Ly-alpha blobs
25” (190kpc)