Resolving the structure and evolution of nearby Galaxy Clusters

Transcription

1 Resolving the structure and evolution of nearby Galaxy Clusters Prof. César A. Caretta (Heinz Andernach, Roger Coziol, Josué Trejo-Alonso, Marcel Chow-Martínez, Juan de Anda Suárez, Humberto Santoyo Ruiz, Miguel Muñiz-Torres, César Hernández-Aguayo) Departamento de Astronomía DCNyE-CGT, Universidad de Guanajuato 2014 August

2 The galaxy clusters Content A2744

3 Abell/Zwicky Regular/ compact Irregular/ open Internal structure Morphology B-M I (cd) II III (no cd) Density isocontours: Geller & Beers, 1982 Luminosity in X-rays: Jones & Forman, 1984 Jones-Forman XD (small rc) axd (large rc) Luminosity segregation: Rood & Sastry, 1971

4 Mass Virial theorem (dynamical equilibrium, velocity dispersion: σv ) ICM density and temperature profiles (hydrostatic equilibrium) Gravitational lensing (strong, weak) Caustics (infall region) Scale relations (self-similarity) Substructuring Detection of subestructures: Bravo Alfaro+, 2009 ROSAT

5 Environmental effects Red sequence: Blakeslee+, 2003 Morphology-density relation: Dressler, 1980 Interaction among the components Gravitational: Harassment: Moore+, 1996 tidal effects (pairs/cluster) harassment merging Hydrodinamical: ram presure stripping thermal evaporation starvation

6 Large Scale Structure Cosmological alignments (Com-Leo Supercluster): West+, 1995 Intra-Supercluster Medium (Shapley Supercluster): Planck Colab., 2013 Structure formation and evolution Dominating galaxies (Per-Pis Supercluster): Caretta, 2008

7 Usual limitations on galaxy cluster samples: Only photometric data (positions and magnitudes) [ statistical membership: Abell-like criteria (m10, RA, m3+2), luminosity functions, etc] Only photometric redshifts (based on color indices) [ large uncertainties] Small number of spectroscopically confirmed members (~10) Case study (many redshifts for only one cluster) Samples which are biased towards certain classes of clusters: X-ray luminous, cd clusters, etc Our sample The 50 best spectroscopically sampled clusters: Detected in the optical (ACO catalog) Local Universe: z < 0.15 More than 100 spectroscopically confirmed members All morfological types and evolutive states represented

8 Spectroscopic data Radial velocity compilation for galaxy member candidates by H. Andernach (130,000 galaxies in 3,930 ACO clusters, at the end of 2012) Distinct redshift components in the line o sight cone of a cluster (A, B, C, in order of growing z) Homogenization Combination of velocities from distinct sources for the same galaxy (averaging, exclusion of outliers) Astrometry: different errors in distinct sources: visual inspection (TopCat + Aladin), addition of homogeneous coordinates from a photometric catalogs Addition of photometric data (optical: SuperCOSMOS, NIR: 2MASS)

9 Membership Original (H.A.) criteria: gaps method (Δv = ± 2,500 km/s, inside R RA b e l l) Caustics method (scape velocity for the gravitational system) 2 v e= 8 G 2 r r 3 r 2 3/ 2 r = 0 [1 ] Rc King's profile A0085 A0539

10 Membership Unbounded groups! Typically (100 < σ < 350) Pre-processing studies

11 Membership Clusters with intersecction in the plane of the sky

12 Center and CDG Central Dominating Galaxies (CDG) Is among the BCMs (brightest cluster members) Located close to the projected density peak Located close to de X-ray emission peak Each subestructure (including de main) has its CDG (may have two) Magnitud gap (Δm1-2) and gap function (m2 to m1 0)

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14 Subestructuring Methods (at least two positives to confirm substructure...) 1D: velocity distribution 2D: projected distribution of members (isocontours), X-ray emission maps 3D: Dressler & Shectman (1988, deltas) Interpretation of Deltas Δ = Σδi ; PD S ; Δ/N ; distribution of δi is not centered on 0.0! 3D distribution of: (vr, vl o c, σl o c) (RA) (Dec) Significance of a subestructure and classification of clusters %N = Ns / Nc > 0.05 M (multi-modal), S (substrured), P (not signif. substr.), U (uni-modal)

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18 Masses Convergence test (Ri = 2.5 Mpc o RA MV RV MV...)

19 Gravitational bounding Newton boundedness criteria: Rp V r R p 2G M sin2 cos Neighbour clusters Vr Subestructures (check if they are really bounded, as expected after caustics)

20 Results on substructuring Classification according to subestructuring P M (13%) + S (38%) 51% P (12%) + U (37%) 49% Significance of subestructures (%N) U (=1.0), P (> 0.8) S ( , <0.2) M ( ) Mass estimates M S

21 Results on CDGs General properties of CDGs BCM is in a substructure other than main: 20% CDG is dumbbell, multiple or interacting galaxy: 25% Distribution of BCMs (above a certain magnitud level) Massive structures: many Less massive: one (CDG)

22 To do list Optical (CDG) X-ray center Optical X-ray morphology Mass and LX among different dynamical status (substruct. classes) Pre-processing groups substructures main/u CMRs CDG properties (p.e. MK), Δm1 2 and gap function among substruct. Classes) New classification for optically selected clusters? Galaxy activity in each substr. class and pre-processing class Large Scale Structure (superclusters and filaments): membership, supercluster environmental effects, alignments, etc. etc...

23 References The red sequence of AXU clusters (tesis: M, D) J. Trejo-Alonso, C.A. Caretta, T.F. Laganá, et al. 2014, MNRAS 441, 776 New catalog of Superclusters of ACO clusters up to z ~0.15 (tesis 2L, M, D) M. Chow-Martínez, H. Andernach, C.A. Caretta, et al., ACCEPTED in MNRAS Galaxy Clusters and CDGs (tesis: 2L) R. Coziol, H. Andernach, C.A. Caretta, et al. 2009, AJ 137, 4795 Y.-Y. Zhang, H. Andernach, C.A. Caretta, et al. 2011, A&A 526, A105 C.A. Caretta, H. Andernach, R. Coziol, et al., IN PREPARATION Environmental effects on Galaxy Clusters (tesis: M, D) C.A. Caretta, J.M. Islas-Islas, J.P. Torres-Papaqui, et al. 2008, Mem.S.A.It. 79, 1201 H. Bravo-Alfaro, C.A. Caretta, C. Lobo, et al. 2009, A&A 495, 379 A. Morales-Vargas, C.A. Caretta, J.M. Islas-Islas, IN PREPARATION