Studies Of Galaxy Clusters Studies Of Galaxy Clusters By BATC Large Field Multi-By BATC Large Field Multi-

Color Sky SurveyColor Sky Survey

--- A brief review of the progresses in recent years

Yanbin, Yang; Xu, ZhouBATC, National Astronomical Observatories, CAS

2005-06-09, 威海 (Wei-Hai)

OutlineIntroductionObservation of Clusters by BATCIndividual ClusterStudies of A168Recent WorksFuture Works

IntroductionIntroduction

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

～ 1x1 sq deg

Magnitude21

Redshift

0.1~0.03

Filter system of BATC

Sepctral Energy Distribution (SED)

Target Clusters

Large field~1x1 sq deg

Multi-color15-filters

Nearby (z<0.1) rich clusters

Observation of Clusters Observation of Clusters by BATCby BATC

Target list I (in 1999)

Target List II

TA26

Target List III

TA27

Target List VI

Individual ClusterIndividual 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 168Abell 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 StudyOptical Study

Photometric Redshift and members

121 (zspec ) + 255 (zphoto )

1553 galalxies ， 18-band SED (r' <20 mag)

13 from BATC 5 from SDSS

zphoto zspec

376 members and candidates

Photometric redshift

光学研究：

光学研究：

Photometric Redshift and members

121 (zspec ) + 255 (zphoto )

1553 galalxies ， 18-band SED (r' <20 mag)

13 from BATC 5 from SDSS

zphoto zspec

376 members and candidates

an01an01

光学研究：

an06an06

光学研究：

(Ulmer,M.~P., Wirth, G.~D., & Kowalski, M.~P. 1992, ApJ, 397, 430)

Optical center

X-ray center

Review3

光学研究：

X-ray StudyX-ray Study

Imaging2

X 射线研究

Imaging3

X 射线研究

north

east

Ricker, P. M. Sarazin, C. L. 2001, ApJ, Ricker, P. M. Sarazin, C. L. 2001, ApJ, 561561, 621, 621

A168 is a merging cluster.

Ulmer, et al. 1992, ApJ, 397, 430Ulmer, et al. 1992, ApJ, 397, 430

In 2004In 2004 In 2004In 2004 Ricker, P. M. Sarazin, C. L. 2001, ApJ, Ricker, P. M. Sarazin, C. L. 2001, ApJ, 561561, 621, 621

Recent WorksRecent Works

(In 2005)

A399-401 (Yuan et al. 2005, ChJAA)

Spatial distributiondynamics

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 dataA119 (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 ~ 0.025 (by more than 200,000 galaxies)

Searching Clusters in SDSS data (Yang et al. draft version)

~6500 cluster candidates over ~580 deg2 (11.2 clusters / deg2)

Future WorksFuture Works

What we have now?1. Early studies focus on the member selecti

on, 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 br

oad 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 selecti

on, 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 bro

ad 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 bands1. >15 fields are covered by SDSS

3. IR : 2MASS4. UV: GALEX5. 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 ThanksMany Thanks

Zfixed = 0.0016Age = 10 (-2,+4) GyrE(B-V) = 1.35 (0.2)