in a Large-Scale Structure at z=3.1 Lyman alpha blobs in a Large-Scale Structure at z=3.1 Yuichi Matsuda (Tohoku Univ. / NAO Japan) collaborators Toru Yamada (NAO Japan) Tomoki Hayashino (Tohoku Univ.) et al. Y. Matsuda et al., AJ, 2004, in press T. Hayashino et al., AJ, 2004, in press Thank you. Good afternoon!! I’m Yuichi Matsuda. I’m gonna talk about Subaru observation of a protocluster at high redshift.

Outline The protocluster at z=3.1 in SSA22 is one of the best field to study high-z galaxies in high density region The previous survey (9’ x 9’) 70 Lyman alpha emitters (Steidel et al. 2000) 2 Lyman alpha blobs Our NB survey (32’ x 24’) 283 Lyman alpha emitters (Hayashino et al. 2004) 35 Lyman alpha blobs (1) A belt-like structure of Lyman alpha emitters (length ≥ 60 Mpc in comoving scale) (2) The first large sample of Lyman alpha blobs (size = 30-200 kpc in physical scale) The protocluster at z=3.1 in SSA22 is one of the best field to study high-z galaxies in high density region The previous narrow-band survey of this protocluster shows it has 70 Lyman alpha emitters and 2 gaint Lyman alpha blobs. But the field of view is nine arcmin times nine arcmin. So we can not know how big this protocluster is and how typical the 2 giant blobs are. In order to answer those questions, we got much wider and much deeper narrow-band image of this protocluster. As a result, we detected about three hundred Lyman alpha emitters and thirty five Lyman alpha blobs. The sky distribution of Lyman alpha emitters show a belt-like structure. The length of this structure is more than 60 Mpc in comoving scale. 35 Lyman alpha blobs we detected are the first large sample of Lyman alpha blobs. The size of the blobs is 30 to 200kpc in physical scale. The first topic is a large scale structure of emission-line galaxies at high redshift. The size of this structure is about 60 Mpc in comoving scale. The next topic is 35 Lyman alpha blobs in this large scale structure. The size of the Lyman alpha blobs is about 100 kpc in physical scale.

Our target field (Steidel et al. 1998, 2000) The protocluster at z=3.1 in SSA22 　　　　　　 (Steidel et al. 1998, 2000) Redshift distribution of Lyman-break galaxies z=3.1 peak The SSA22 z=3.1 peak of Lyman-break galaxies has δρgal/ρgal = 5 in 16 x 16 x 37 Mpc N First, I’m gonna talk about our target field, the protocluster at z=3.1 in SSA22. This protocluster was discovered by Steidel et al. in 1998. They found a large peak in redshift distribution of Lyman break galaxies in SSA22. This peak is also the largest peak in their 17 survey fields. The SSA22 z=3.1 peak is the largest peak in their 17 survey fields of Lyman-break galaxies at z~3 Redshift

Our target field (Steidel et al. 1998, 2000) The protocluster at z=3.1 in SSA22 　　　　　　 (Steidel et al. 1998, 2000) Steidel et al. (2000) got a deep narrow-band image of the protocluster. 16Mpc They got a deep narrow-band image of this protocluster. They found a lot of Lyman alpha emitters in this protocluster. They found 70 Lyman alpha emitters. 16Mpc

Our target field (Steidel et al. 1998, 2000) The protocluster at z=3.1 in SSA22 　　　　　　 (Steidel et al. 1998, 2000) They also found 2 giant (~200kpc) Lyman alpha blobs. 300kpc Blob1 and Blob2 have Sub-mm sources. (Chapman et al. 2001) SFR ~ 1000 Mo/yr Formation of massive galaxies? They also found 2 giant Lyman alpha blobs. They called the blobs, blob1 and blob2. The size of the blobs is about 200kpc in physical scale. Blob1 and blob2 have sub-millimeter sources. Star formation rate estimated from sub-millimeter flux is about one thousand solar mass per year. So the 2 giant blobs may be related to formation of massive galaxies. Continuum Lyman alpha

Our observation We got 9 times wider and 0.4 mag deeper narrow-band image of the SSA22 protocluster at z=3.1 Our field of view 32’ x 24’ Steidel et al. (2000) 9’ x 9’ Subaru 8m telescope Suprime-Cam Narrow-band filter 7.2 hour exposure!! 45Mpc The field of view of narrow-band image by Steidel et al. is nine arcmin times nine arcmin. How big is this protocluster? How typical are the 2 giant blobs? We need wider and deeper narrow-band image of this protocluster. We used Subaru 8m telescope and the prime focus camera, Suprime-Cam. We got 9 times wider and 0.4mag deeper image. 60Mpc

(1) Large scale structure at z=3.1 We found a belt-like structure of ~300 Lyman alpha emitters (length ≥ 60 Mpc in comoving scale) Our field of view 32’ x 24’ 283 Lyman alpha emitters Photometry 2” diameter aperture Lyman alpha flux > 2 x 10-17 ergs/s/cm2 EWobs > 170A 45Mpc Lyman alpha blobs The first question is how big this protocluster is. We detected about 300 Lyman alpha emitters. This is the skymap of Lyman alpha emitters. The region inside this red line is high density region of emitters. We found a belt-like structure of high density region. The length of this structure is more than 60 Mpc in comoving scale. δρgal/ρgal ~ 2 60Mpc

(1) Large scale structure at z=3.1 Large filament of emitters (length ≥ 60 Mpc & radius ~10Mpc) 56 spectroscopically confirmed Lyman alpha emitters at z=3.1 Subaru 8m telescope FOCAS MOS 0.8-1.5 hour exposure!! 45Mpc We got spectra of emitters in this belt-like structure. We have no contamination in our sample of Lyman alpha emitters. We found the belt-like structure is continuous large filament in 3 D space. The radius of this filament is about 10 Mpc. No contamination by [OII] and [OIII] emitters 60Mpc

(2) Lyman alpha blobs We could resolved detail structures 300kpc Green shows Lyman alpha The next question is how typical the 2 giant blobs are. Our narrow-band image is very deep, so we could resolve detail structure of Blob1 and Blob2. Can we get new Lyman alpha blobs? 200 kpc Continuum Lyman alpha Steidel et al. (2000) Our deep images

(2) Lyman alpha blobs We found 33 new Lyman alpha blobs Lyman alpha emitters 35 Lyman alpha blobs Photometry isophotal aperture Lyman alpha flux > 7 x 10-17 ergs/s/cm2 EWobs>80A Size > 30 kpc Lyman alpha blobs are more concentrated!! 45Mpc Blob1 and Blob2 Yes!! We could find 33 new Lyman alpha blobs in our image. We selected Lyman alpha blobs with the size more than 30 kpc in physical scale. Here is sky map of Lyman alpha blobs and Lyman alpha emitters. Lyman alpha blobs are more concentrated in the belt-like structure. δρgal/ρgal ~2 60Mpc

(2) Lyman alpha blobs The first large sample of Lyman alpha blobs 35 Lyman alpha blobs have large varieties Blob1 Blob2 Blob1 and Blob2 are the largest and the brightest in our 35 sample. The 35 blobs have large varieties of size, surface brightness, and morphology. This is the first large sample of Lyman alpha blobs. The first large sample of Lyman alpha blobs 200kpc

(2) Lyman alpha blobs Large varieties different origins? (1) Photoionization by massive stars or by AGN (in some cases … may be hidden by dust) (2) Cooling radiation in collapsing halo (e.g. Haiman et al. 2000) (early phase of galaxy formation) (3) Galactic superwind (e.g. Taniguchi & Shioya 2000) (late phase of intense star formation) Plus, scattering.. The large varieties of blobs may show difference of their origins. The simplest model is photoionization by massive stars or by AGN. The second model is cooling radiation in collapsing halo. The third model is galactic superwind. Scattering must be important in all of the blobs.

(2) Lyman alpha blobs Choice of the continuum object: Lyman alpha flux vs. UV continuum flux Choice of the continuum object: the nearest source to the Lyman alpha peak, or the known LBG Blob1 Blob2 Lyman alpha Excess Can we explain the origin of the blobs by photoionization? We compared the Lyman alpha flux and UV continuum flux. The green line shows expected Lyman alpha flux from their UV flux of massive stars. Now we assume no dust and Salpeter IMF. About 30% blobs show Lyman alpha excess. So we can not explain the origin of Lyman alpha blobs by massive star photoionization. Actually, we have good candidates of cooling radiation or galactic superwind. 14 / 35 blobs show Lyman alpha Excess to the massive star photoionization (no dust, Salpeter IMF).

(2) Lyman alpha blobs Galactic superwind? Conical structure 200kpc For example, this blob has conical structure. This structure may be evidence for galactic superwind. Galactic superwind? 200kpc

(2) Lyman alpha blobs Galactic superwind? Cooling radiation? Blob1 Bubble-like structure Galactic superwind? (see also Ohyama et al. 2003) or Cooling radiation? Velocity structure is chaotic (Bower et al. 2004) Blob1 has bubble-like structure. This may also be evidence for galactic superwind. 200kpc

(2) Lyman alpha blobs Cooling radiation from collapsing halo? This blob does not have plausible continuum source. We think this is a good candidate for cooling radiation from collapsing halo. Diffuse nebulae & No plausible continuum source 200kpc

Summary The protocluster at z=3.1 in SSA22 has (1) Large filament of Lyman alpha emitters (length ≥ 60 Mpc in comoving scale) (2) 35 Lyman alpha blobs ( size = 30-100 kpc in physical scale) The first large sample of Lyman alpha blobs More concentrated then emitters Blob1 and Blob2 are the largest and the brightest blobs 1/3 has Lyman alpha excess to massive star photoionization Good sample of forming galaxies in high density region at high redshift This is the summary of my talk. Thank you.