1 / 31

Radio galaxies in 6dFGS: influence of the supercluster environment ?

Radio galaxies in 6dFGS: influence of the supercluster environment ?. Jean-Christophe Mauduit 1 , Gary Mamon 1 , Gary J. Hill 2. 1 Institut d’Astrophysique de Paris, 2 University of Texas at Austin. Credits : A Flight Through the Universe -- Swinburne University -- P. Bourke.

maya
Download Presentation

Radio galaxies in 6dFGS: influence of the supercluster environment ?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Radio galaxies in 6dFGS: influence of the supercluster environment ? Jean-Christophe Mauduit1, Gary Mamon1, Gary J. Hill2 1 Institut d’Astrophysique de Paris, 2 University of Texas at Austin Credits : A Flight Through the Universe -- Swinburne University -- P. Bourke

  2. Large scale studies with correlation functions : 5 < r0 < 15 h-1 Mpc Peacock & Nicholson 91, Bahcall & Chokshi 92, Blake & Wall 02, Overzier et al. 03, Magliochetti et al. 04, Croom et al 04, Brand et al. 04 … RGs cluster more strongly than gals but less than rich clusters. but where are they ? What do we know about radio galaxy environments ? • AGNs in cores of compact groups, SBGs rise from core to halo, Coziol et al. 98 • AGNs found within 3 Mpc of a cluster center, Soechting et al 02 • Increase of RG activity in clusters, Miller & Owen 99 • Decrease of ‘’ ‘’ , Giancintucci 03, Venturi et al. 00 No clear picture from various studies ! Degeneracy pb:  RG types,  redshift,  environments …

  3. Motivations • If RGs trace structures : good probes of LSS to high-z (RGs luminous, rare and radio non affected by dust) And in local superclusters z < 0.1? Shapley supercluster (SSC) Brand et al. 03 • Distribution of radio gals. in SC, cluster complexes and clusters • Effects of environment on radio galaxies: AGNs and starbursts triggered, starved ? Dependency on dynamical state of the structure ?

  4. Optical input catalogs: 6dFGRS U FLASH • FLASH – FLAIR Hydra Shapley • (Kaldare et al. 2003) • Hydra-Centaurus cat based (UKST) • limit of • 3141 galaxies with redshift FLASH • 6dFGS: 6 degree Field Galaxy Survey (Jones et al. 2004) • K 12.75, 52081 galaxies • only quality factor of Q = 4 • doubles removal • selection in FLASH area 4018 galaxies retrieved 6dF 6365 galaxies total

  5. Shapley supercluster Broad connecting arm Front Eastern Wall Core (A3558) Northwestern extension (Abell 3528) A tour of the area via the final catalog

  6. Radio catalogue NVSS (Condon et al .1998) (FIRST not reaching far enough south) 99% complete at 45” resolution 68000 candidates Cross-identification between radio and optical galaxies • Redshift catalogues : • FLASH (Kaldare et al. 2003) • 6dFGS (Colless et al. 2001) Cross-ID within 15” Visually checked matches Radio contours start from 3σ by step of √2

  7. Overall distribution of radio galaxies in LSS • Radio galaxies trace fairly well the overall large scale structure Highly incomplete beyond 20000 kms-1 Pb for statistical investigation of the area : Malmquist bias Restriction to “SSC area” in velocity space due to the completeness limit : 10000 < v < 18800 kms-1

  8. ‘’Blind’’ classification between AGNs & SBGs In our radio galaxy sample : SFGs, SBGs, AGNs ? Figure from Sadler et al. 02 also shown is Machalski & Godlowski 00 AGN / SBG limit :

  9. Rough radio galaxy classification • Selection effects Volume-limited sample : Yun et al. 01 : SFG / SBG limit : 29 AGNs & 155 SBGs + AGN / SBG limit :

  10. A qualitative view of the RG distribution in the area Legend : Black = All galaxies Red = AGNs Blue = SBGs Green = Clusters

  11. Estimation of the environment density of RGs • Use of Gaussian smoothed densities on different scales • Compute comoving or ang. separations between RGs & opt. gals • Derive ρ for : • Normalize to N random catalogs (same boudaries, smooth velocity distribution) Projected space Redshift-space

  12. Taking care of the boundary problems (α,v ) ( α,δ ) Random catalog generation (αrdm,vrdm ) ( αrdm,δrdm ) Data (black) Fit & simulated catalog(red) (α,δ) plots (α,v) plots black ellipse shows SSC cut out

  13. The raw statistics Log LR/LK Log LR

  14. 3 Mpc 20 Mpc Estimating environment density of RGs Lradio/LK vs rho_env • Spearman tests on smoothed densities • Significant anti-correlation at big scales (> 99 %) • when looking at Lradio/LK vs environment • Characteristic cut scales : • - Maximum scale at which no loss of correlation/significance : 3 Mpc • - Loss of correlation/significance : 20 Mpc • Let’s look at cluster complexes …

  15. Distribution in clusters complexes • KS test on radio luminosity in two cluster complexes red = galaxies within 8 h-1 Mpc of center, black = rest • Lradio distrib. in A3558 complex could be similar to the rest of the area (c.f. also quantitative results from Venturi et al. 00) • Lradio distrib. in A3528 complex significantly different

  16. Cluster selection and stacking • 30 clusters in the area Table fromStruble & Rood 1999, include: position, radii, members & σ using pure NFW model : Re-selecting cluster galaxies with : Stacking of clusters in SSC area in (see Lokas & Mamon 2001)

  17. Temporary results ! Cumulated cluster profiles Same situation for radio-loud Radio-quiet prefer outer regions Radio-loud follow overall distrib. Radio-quiet seem more concentrated inside clusters Results differ from more general investigations of Best 04, Kauffmann et al. 04 ( SFG fraction decrease with increasing density)

  18. Comparison to projected NFW profiles NFW mass profiles (NFW 1997) Projected mass profiles e.g. : Lokas & Mamon 2001

  19. Best (2004) finds 9 radio-loud AGNs in super-structure at z = 0.084 Brand et al. (2003) : 12 RGs at z = 0.3 in 100 Mpc large superstructures SSC in a special dynamical state at z = 0.05 ? Evidence for cluster-cluster merging ! • Equal-mass cluster merging : more encounters but less merging (too rapid) & rps more effective (cluster-cluster merging dynamics) depends on the dynamical state of the merging • Substructure merging • Epoch of merging event important, Hanami et al. 99 Stops radio activity ?

  20. Summary • Anti-correlation at large scales (significant for LR/LK) • Cluster complexes different : central one devoid of RGs • No overall quenching inside clusters ? Not understood ... Work in progress • Link cluster-cluster merger & SC dynamics to RG activity • Need to carry out similar analysis on other supercluster (w/ diff. dynamics and/or at higher redshift) Radio galaxy distribution depends on the overall dynamical state of the LSS

  21. SSC through cosmic flows ? SSC Possible detection : Hoffman et al. astro-ph/0102190

  22. Possible prospective studies • 6dF-v : 15 000 galaxies (E/S0) Distances FP • Velocity fields and density fields Bias : • Shapley dynamics via 6dF-v ? a possible amount of  100 galaxy peculiar velocities in the SSC ? able to see internal flows within the SSC ?

  23. Thank you !

  24. Clusters velocity dispersions vs distance to SSC center

  25. Lradio Lradio / LK angular z-space There is a significant anti-correlation at large scales – reinforced by SSC cut out !

  26. Reminder (1): radio galaxies • AGNs : Seyferts, FRI, FRII, Blazars … unified scheme model radio-quiet/loud fueling of the BH • SBGs : SFR higher than average bright at radio, IR, X-ray result of interactions, tidal, collisions several periods of activity ?

  27. Reminder: large-scale structures scales (LSS) Typical scales of structures : • Groups& poor clusters : , , • Rich clusters : , , • Superclusters : ,

More Related