Studies Of Galaxy Clusters By BATC Large Field Multi-Color Sky Survey --- A brief review of the progresses in recent years Yanbin, Yang; Xu, Zhou BATC, National Astronomical Observatories, CAS , 威海 (Wei-Hai)

Outline Introduction Observation of Clusters by BATC Individual Cluster Studies of A168 Recent Works Future Works

Introduction

A cluster picture Clusters is related to large scale structures, and also to individual galaxies. Give the curtial constrians on cosmology and galaxy evolution.

～ 1x1 sq deg Magnitude 21 Redshift 0.1~0.03

Filter system of BATC

Sepctral Energy Distribution (SED)

Target Clusters Large field ~1x1 sq deg Multi-color 15-filters Nearby ( z<0.1 ) rich clusters

Observation of Clusters by BATC

Target list I (in 1999)

Target List II TA26

Target List III TA27

Target List VI

Individual Cluster Past works (< 2004)

A2634 z=0.031, Yuan et al. 2001, AJ, 122, 1718

A566 z=0.097, Zhou et al. 2003, PASJ, 55, 891

A2255 z=0.08, Yuan et al. 2003, ApJS, 149, 53

A168 z=0.045, Yang et al. 2004, ApJ, 600, 141

Abell 168 “Large-Field Multicolor Study of A168: Subclusters, Dynamics, and Luminosity Functions”, Yang, Yanbin; Zhou, Xu; Yuan, Qirong; Jiang, Zhaoji; Ma, Jun; Wu, Hong; Chen, Jiansheng, The Astrophysical Journal, 2004, 600,141 “Chandra X-Ray Observations of Galaxy Cluster A168”, Yanbin Yang, Zhiying Huo, Xu Zhou, Suijian Xue, Shude Mao, Jun Ma, and Jiansheng Chen, The Astrophysical Journal, 2004, 614, 692

Optical Study

Photometric Redshift and members 121 ( z spec ) ( z photo ) 1553 galalxies ， 18-band SED ( r' <20 mag) 13 from BATC5 from SDSS z photo z spec 376 members and candidates

Photometric redshift

光学研究：

Photometric Redshift and members 121 ( z spec ) ( z photo ) 1553 galalxies ， 18-band SED ( r' <20 mag) 13 from BATC5 from SDSS z photo z spec 376 members and candidates

an01 光学研究：

an06

(Ulmer,M.~P., Wirth, G.~D., & Kowalski, M.~P. 1992, ApJ, 397, 430) Optical center X-ray center

Review 3 光学研究：

X-ray Study

Imaging 2 X 射线研究

Imaging 3 X 射线研究

north east Ricker, P. M. Sarazin, C. L. 2001, ApJ, 561, 621

A168 is a merging cluster. Ulmer, et al. 1992, ApJ, 397, 430 In 2004 Ricker, P. M. Sarazin, C. L. 2001, ApJ, 561, 621

Recent Works (In 2005)

A (Yuan et al. 2005, ChJAA) Spatial distribution dynamics A2634 (Wen et al.; submitted; receive the first refree ’ s report; submitted again) Spatial distribution Star formation (by PEGASE model) A2255 (Yuan et al. 2005, submitted to ApJ) Star formation; SDSS spectroscopic data A119 (Yuan et al. in prep.) A168 (Kim, et al. in prep.; an cooperation with Seoul Univ.) Star formation, blue galaxies. Searching Clusters in SDSS data (Yang et al. in prep.)

Potometric redhsift with SDSS five bands (Yang et al. draft version) △ z ~ (by more than 200,000 galaxies)

Searching Clusters in SDSS data (Yang et al. draft version) ~6500 cluster candidates over ~580 deg 2 (11.2 clusters / deg 2 )

Future Works

What we have now? 1. Early studies focus on the member selection, spatial distribution, luminosity function and dynamics. 2. Recently, Yuan ’ s work (also Wen ’ s) push us into the study of Star formation in clusters. 3. Mature experiences in 1. Photometric redshit with intermediate and broad bands (Zhou, X.; Yuan, Q.R.; Yang, Y.B.; Xia, L.F.; Wen, Z.L.)

RMS ~0.015 RMS ~0.023

What we have now? 4. Early studies focus on the member selection, spatial distribution, luminosity function and dynamics. 5. Recently, Yuan ’ s work (also Wen ’ s) push us into the study of Star formation in clusters. 6. Mature experiences in 1. Photometric redshit with intermediate and broad bands (Zhou, X.; Yuan, Q.R.; Yang, Y.B.; Xia, L.F.; Wen, Z.L.) 2. PEGASE (Li, J.L.; Duan, Z.Y.;) 3. SSP (Ma, J., Wu, Z.Y.,) 4. SED analyser by  2 minimization motivated by Wang X.F.; Ma, J.; Zhou, X.; Korea cooperation (Yang, Y.B.)

What we have now? 7.Multi-band data of 1. BATC : 1. Data of 20 /36 Clusters (z<~0.1) is ready; 2. We have so many observations (>107 fields) 2. SDSS : Spectra & 5 broad bands 1. >15 fields are covered by SDSS 3. IR : 2MASS 4. UV: GALEX 5. X-ray : Chandra, ROSAT, Einstein, etc.

Then, What we can talk about? Membership, spatial characters, luminosity function, dynamical status. Star formation in nearby cluster: metallicity, Age, star formation rate and compare them with field. Galaxy evolution and dynamics of cluster: how merging processes trigger star formation.

Many Thanks

Z fixed = Age = 10 (-2,+4) Gyr E(B-V) = 1.35 (0.2)