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)

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

The Clowes-Campusano LQG Survey  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 Mpc with concentrations of 5-20 QSO's  to large to be virialized, probable relics of large scale fluctuations  rare (4σ) structures, ~1/3 space density of super-clusters Background: LQGs

The Clowes-Campusano LQG Survey  duration of QSO phase ~10 7 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) = ( n r 2 / n 2 ) - 1 ⇩ search for Large Scale Structures How to find them?

The Clowes-Campusano LQG Survey Barrow et al Zwicky Galaxy Catalog 2 Random 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

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: w 1 (l) = 1/l 0 exp(-l/l 0 ) with = l 0 2D: w 2 (l) = 2l/l 0 2 exp(-l 2 /l 0 2 ) with = √( 2 π)/2 l 0 ⇩ minimal tree if sum of length of segments is minimal  MST can be used to identify under- and over-dense regions

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

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

The Clowes-Campusano LQG Survey MST pruned to level 10 (branches k ≤ 10 removed) mean edge length: = rad (1.232 ° ) and = (1.530 ° )

The Clowes-Campusano LQG Survey MST pruned and separated cut-offs: 2 and 1.6 ⇒ rad (3.142 ˚ ) separation in both cases

The Clowes-Campusano LQG Survey Barrow et al Zwicky Galaxy Catalog 2 Random 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

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

The Clowes-Campusano LQG Survey frequency distribution of MST(Zwicky) shows excess of large and small l z frequency distribution of MST (random) follows Gauss distribution centered on

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 (B J ≤ 20.0 mag) on scales ~60 h -1 Mpc  Clowes & Campusano (1991) – CCLQG 18 QSOs at z~1.3 (B J ≤ 20 mag) on scales ~120 x 240 h -2 Mpc 2 elongated overall and clumpy inner structure  Komberg et al. (1996) 10 LQGs from nearest neighbor method  10 – 25 QSOs with M B < -23 mag  z ~ 0.6 – 2.1 and  40 – 160 h -1 Mpc scales

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 l 0 3 / ≈ 10  6 LQGs with 15 – 19 members on scales ~140 h -1 Mpc (Jumbo LQGs) spatial overdensity l 0 3 / ≈ 4  space density: ≃ 7 h 3 Gpc 3 ⇨ ~500 – 1000 “Jumbo” LQGs  morphologies: = 0.8 ⇨ walls+blobs ( ε = L trunk /L tree <1) rather than filaments ( ε ~1)

The Clowes-Campusano LQG Survey History of the Clowes-Campusano LQG  automated search on UKST objective-prism plate (~25.3 deg 2 ) 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< QSOs with 1.2≤z≤1.4 = selection effect by the objective-prism Ly-α emission shifted in the blue at z>1.8 cover 2.5 ° x 5 ° on the sky banana like structure 8 additional QSOs from spectr. follow-up (Clowes et al. 1999)

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

The Clowes-Campusano LQG Survey CCLQG z~1.3LQG z~0.8 3 x MgII-absorber overdensity2 x MgII-absorber overdensity discovery of 2 nd foreground LQG Williger et al. 2002

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

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

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

The Clowes-Campusano LQG Survey Survey Summary

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

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

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

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): m NUV ≤ 24.5 mag + FUV – NUV ≥ 2 additional selection criteria: SDSS photo type = “GALAXY” resulting sample of 1,023 LBG candidates

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 z SDSS = 0.06 for z ≤ 0.4 z MegaZ = 0.08 for 0.4 ≤ z ≤ 0.8

The Clowes-Campusano LQG Survey photometric redshift distribution LBG candidates z = 0.05

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

The Clowes-Campusano LQG Survey SFHs of averaged LBG SEDs 2 -fit of averaged and normalized LBG SEDs to library of P È GASE models ⇒ 3 Gyr ≤ t best ≤ 7 Gyr ⇒ 3 Gyr ≤ t best ≤ 7 Gyr although fits with 250 ≤ t youngest ≤ 800 are acceptable

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

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

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

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 deg 2

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

The Clowes-Campusano LQG Survey