The Clowes-Campusano Large Quasar Group Survey

1. The Clowes-Campusano Large Quasar Group Survey L. Haberzettl G. Williger (UofL, USA) J.T. Lauroesch (UofL, USA) M. Graham (Caltech, USA) R. Davé (Steward Obs., USA) A. Koekemoer (STScI, USA) L. Campusano (Univ. de Chile, CL) R. Clowes (Univ. Lancashire, UK) I. Soechting (Univ. Lancashire, UK) K. Harris (Univ. Lancashire, UK) C. Haines (Univ. Birmingham, UK) J. Loveday (Univ. Sussex, UK) D. Valls-Gabaud (Obs. de Paris, F) N. Nesvadba (Obs. de Paris, F)

2. The Clowes-Campusano LQG Survey Outline Background - How to find them? - Significance of LQGs - History of the CCLQG The CCLQG Survey LBGs in the CCLQG Future

3. The Clowes-Campusano LQG Survey Background: LQGs • discovered first by Webster 1982 →close triplet + one more distant • QSO at z~0.37 scales ~75 h-1 Mpc • two other LQGs: Crampton et al. (87,89; 23 QSOs) at z~1.1 • Clowes & Campusano (1991; 18 QSOs) z~1.3 • large irregular shaped, filamentary structures on scales of 50-200 Mpc • with concentrations of5-20 QSO's • to large to be virialized, probable relics of large scale fluctuations • rare (4σ) structures,~1/3 space densityof super-clusters

4. The Clowes-Campusano LQG Survey How to find them? • duration of QSO phase ~107 yr ⇒ much shorter than timescale for • quiescent evolution of AGN and age of Universe • at any time only small number of galaxies in QSO phase • ⇩ • QSOs should be randomly distributed • comparing real QSO distributions to catalogs of random object • distributions using spatial correlation functions • ξ(r) = (<DD(r)>nr2/<RR(r)>n2) - 1 • ⇩ • search for Large Scale Structures

5. The Clowes-Campusano LQG Survey Barrow et al. 1985 2Zwicky Galaxy Catalog 2Random Sample 1091 galaxies in the North Galactic Cap with Pmag ≤ 14 mag and δ≥0 and b≥40° 1091 galaxies over the same sky area

6. The Clowes-Campusano LQG Survey Minimal Spanning Tree (e.g. Barrow et al. 1985) • generalization of the nearest-neighbor or friend-of-friend method • connecting points with unique path • distribution in tree length: • 1D: w1(l) = 1/l0 exp(-l/l0) • with <l> = l0 • 2D: w2(l) = 2l/l02 exp(-l2/l02) • with <l> = √(2π)/2 l0 • ⇩ • minimal tree if sum of length of segments is minimal • MST can be used to identify under- and over-dense regions

7. The Clowes-Campusano LQG Survey • defining thresholds for max. (over-dense) and min. (under-dense) • length of branches lt and the min. number of objects in a domain M • ⇒ 3D: density of clusters with l ≥lt is higher than minimum density • ρt≡<ρ><l3>/lt3 • ⇧ • strongly depends on the choice of lt,M and determining the • statistical significance

8. The Clowes-Campusano LQG Survey Finding Structures (Barrow et al. 1985) • two reduction methods to find • structures • a) pruning: remove all branches • with k≤p • b) separating: remove edges who • exceed cut-off length

9. The Clowes-Campusano LQG Survey MST pruned to level 10 (branches k≤ 10 removed) mean edge length:<lz> = 0.0215 rad (1.232°) and <lr> = 0.0267 (1.530°)

10. The Clowes-Campusano LQG Survey MST pruned and separated cut-offs: 2<lz> and 1.6<lr> ⇒ 0.043 rad (3.142˚) separation in both cases

11. The Clowes-Campusano LQG Survey Barrow et al. 1985 2Zwicky Galaxy Catalog 2Random Sample 1091 galaxies in the North Galactic Cap with Pmag ≤ 14 mag and δ≥0 and b≥40° 1091 galaxies over the same sky area

12. The Clowes-Campusano LQG Survey 3D-MST pruned and separated cut-offs: 3<lCfA> and 1.8<lr> ⇒ 10.2 Mpc separation in both cases only branches with ≥10 edges are shown

13. The Clowes-Campusano LQG Survey frequency distribution of MST(Zwicky) shows excess of large and small lz frequency distribution of MST (random) follows Gauss distribution centered on <lr>

14. The Clowes-Campusano LQG Survey Statistical Significance of LQGs • first known LQGs: • Webster et al. (1982) – triplet at z~0.37 and one more distant QSO on scales ~75 h-1 Mpc • Crampton et al. (1987) – CCH LQG 18 QSOs at z~1.1 (BJ≤ 20.0 mag) on scales~60 h-1 Mpc • Clowes & Campusano (1991) – CCLQG 18 QSOs at z~1.3 (BJ≤ 20 mag) on scales ~120x240 h-2Mpc2elongated overall and clumpy inner structure • Komberg et al. (1996) 10 LQGs from nearest neighbor method • 10 – 25 QSOs with MB< -23 mag • z ~ 0.6 – 2.1 and • 40 – 160 h-1 Mpc scales

15. The Clowes-Campusano LQG Survey • Pilipenko (2007) ⇨extended QSO clusters search in 2dF+SDSS QSO • catalogs (> 100,000 QSOs) • 18 new LQG identified by MST + 2 LQG confirmed • 6 – 16 QSOs on scales ~40 – 155 h-1 Mpc • two groups of LQGs • 14 LQGs with 6 – 8 members on scales ~60 h-1 Mpc • spatial overdensity l03/<l3> ≈ 10 • 6 LQGs with 15 – 19 members on scales ~140 h-1 Mpc (Jumbo LQGs) • spatial overdensity l03/<l3> ≈ 4 • space density: <ρ> ≃ 7 h3Gpc3 ⇨~500 – 1000 “Jumbo” LQGs • morphologies: <ε> = 0.8 ⇨walls+blobs (ε = Ltrunk/Ltree<1)rather than filaments (ε~1)

16. The Clowes-Campusano LQG Survey History of the Clowes-Campusano LQG • automated search on UKST objective-prism plate (~25.3 deg2) UJ5846P • ESO/SERC field 927 • α = 10:40:00 δ=+05:30:00 • 61 QSOs (29 S-band + 32 W-band) with 0.14<z<2.8 • 10 QSOs with 1.2≤z≤1.4 selection effect by the objective-prism Ly-α emission shifted in the blue at z>1.8 <z> = 1.267 • cover 2.5° x 5° on the sky • banana like structure • 8 additional QSOs from spectr. • follow-up (Clowes et al. 1999)

17. The Clowes-Campusano LQG Survey • clustering scale ~1° (~35 h-1 Mpc) • power spectrum analysis Power Spectrum Analysis 2D MST Q=1 no clustering

18. The Clowes-Campusano LQG Survey CCLQG z~1.3 LQG z~0.8 3 x MgII-absorber overdensity 2 x MgII-absorber overdensity discovery of 2nd foreground LQG Williger et al. 2002

19. The Clowes-Campusano LQG Survey Haines et al. 2004 CTIO BTC 4m V,I data ~0.25 deg2 subfield 31 x 27 h-2 Mpc2 at z ~ 1.2 2 x overdensity in red galaxies 3 x overdensity in red galaxies dashed contour ≙ 1.65 gal. arcmin-2

20. The Clowes-Campusano LQG Survey Clowes-Campusano Large Quasar Group Survey ~2 deg2 imaging and spectroscopy survey from UV – NIR

21. The Clowes-Campusano LQG Survey Existing Data Set: • 2 x 1.2˚ GALEX FUV+NUV • mlim~24 mag • SDSS u,g,r,i,z • ~1.6˚ Bok g ⇒ mlim ~ 26 mag • 2 x 1˚CFHT r+z ⇒ mlim ~ 26 mag • mlim ~ 24 mag • ~1.2˚KPNO 2.1m FLAMINGOS • NIR J+Ks ~600 Magellan IMACS spectra 2 additional GALEX observations as part of the Deep Imaging Survey

22. The Clowes-Campusano LQG Survey Survey Summary

23. The Clowes-Campusano LQG Survey FUV NUV completeness of GALEX data IRAF+Galfit: - GALEX background - IRAF artificial galaxy catalog - Galfit photometry - SExtractor search N S 80-90% complete down to mFUV,NUV = 24 mag ~70% complete down to mNUV = 24.5 mag

24. The Clowes-Campusano LQG Survey Survey Aim • galaxy populations in LQGs • Lyman Break Galaxies (LBGs) • red galaxy population • environmental effects on galaxy evolution • red sequence/blue cloud at z~1 in dense environment • QSO/AGN feedback mechanism • Large Scale Structure (LSS) formation and evolution

25. The Clowes-Campusano LQG Survey Lyman Break Galaxies (LBGs) search for LBGs at z~1 using FUV-dropout technique Lyman Break 912 Å at z~1 FUV-dropout examples: FUV NUV SDSS NUV FUV

26. The Clowes-Campusano LQG Survey LBG search + selection criteria GALEX NUV selected sample: ~15,800 objects SDSS DR5 cross-correlation: ~13,800 primary counter parts selection criteria for LBGs from Burgarella et al. (2006): mNUV≤ 24.5 mag + FUV – NUV ≥ 2 additional selection criteria: SDSS photo type = “GALAXY” resulting sample of 1,023 LBG candidates

27. The Clowes-Campusano LQG Survey photometric redshifts: Hyperz (Bolzonella et al. 2000) 7 band photometry – FUV,NUV+5 SDSS bands compared to SDSS spectroscopy & MegaZ catalog zSDSS = 0.06 for z≤0.4 zMegaZ = 0.08 for 0.4≤z≤0.8

28. The Clowes-Campusano LQG Survey photometric redshift distribution LBG candidates z = 0.05 LQG@z~0.8 CCLQG@z~1.3

29. The Clowes-Campusano LQG Survey selecting redshift+luminosity limited subsample 2 redshift bins in front of the LQGs LQG@z~0.8 CCLQG@z~1.3 bright: MNUV≤ M*NUV faint: MNUV> M*NUV Arnouts et al. (2005)

30. The Clowes-Campusano LQG Survey SFHs of averaged LBG SEDs 2-fit of averaged and normalized LBG SEDs to library of PÈGASE models LQG@z~0.8 ⇒ 3 Gyr ≤tbest≤ 7 Gyr although fits with 250 ≤ tyoungest ≤ 800 are acceptable CCLQG@z~1.3 ⇒ 3 Gyr ≤tbest≤ 7 Gyr

31. The Clowes-Campusano LQG Survey ~500 Myr results for best fitting ages show significant older tbest than Burgarella et al. 2007 (250≤tbest≤500 Myr) Burgarella sample include fainter LBGs ⇒ younger star bursts ⇒ younger averaged SEDs? Role of dust? ~250 Myr

32. The Clowes-Campusano LQG Survey LBG concentrations + filaments LBGs in proximity to QSOs ⇒ QSO feedback mechanism?

33. The Clowes-Campusano LQG Survey red galaxies tend to avoid QSOs formation of large filaments

34. The Clowes-Campusano LQG Survey

35. The Clowes-Campusano LQG Survey Future Plans immediate future: - Bok+90prime observations g in southern field medium band imaging (N,S) - CFHT queue observation r+z extend existing field ~5 deg2

36. The Clowes-Campusano LQG Survey next projects: - stellar masses of LQG galaxies (LBG+red) - spatial correlation analysis - color evolution at z~1-1.5? - global SFRs at z~1? - LSB galaxies - AGN contribution in the LQGs - search for more “jumbo” LQGs - morphologies of LQG galaxies

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