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COLD FRONTS IN CLUSTERS AND THE PECULIAR VELOCITY OF THEIR BCGs FABIO GASTALDELLO INAF-IASF MILAN & UC IRVINE M. MESSA S. GHIZZARDI, M. ROSSETTI, D. ECKERT,

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Presentation on theme: "COLD FRONTS IN CLUSTERS AND THE PECULIAR VELOCITY OF THEIR BCGs FABIO GASTALDELLO INAF-IASF MILAN & UC IRVINE M. MESSA S. GHIZZARDI, M. ROSSETTI, D. ECKERT,"— Presentation transcript:

1 COLD FRONTS IN CLUSTERS AND THE PECULIAR VELOCITY OF THEIR BCGs FABIO GASTALDELLO INAF-IASF MILAN & UC IRVINE M. MESSA S. GHIZZARDI, M. ROSSETTI, D. ECKERT, S. DE GRANDI, S. MOLENDI

2 PECULIAR VELOCITY OF BCGs AND X-RAY THERMODYNAMICAL STATE / PRESENCE OF CFs THE IMPORTANCE OF ASSESSING SUBSTRUCTURES FOR THE ESTIMATES OF PECULIAR VELOCITIES: THE CASE OF A2626 OUTLINE

3 PECULIAR VELOCITIES OF BCGs AND X-RAY STATE CROSS-MATCH OF X-RAY PEAK AND BCG POSITION. ONLY IN EXTREME MERGERS (A754, A3376) LARGE SEPARATION. RESULTING SAMPLE OF 54 OBJECTS COZIOL ABELL CLUSTERS W/ MORE THAN 10 MEMBERS V P OF BCG CAVAGNOLO CLUSTERS K 0 AS INDICATOR OF THERMODYNAMICAL STATE FG, Messa, et al. in prep

4 PECULIAR VELOCITIES OF BCGs AND X-RAY STATE CC NCC

5 V P OF BCGs AND X-RAY STATE KENDALL TEST: 93.2% KS TEST 97.7 %

6 CAVEAT: SUBSTRUCTURES ! v cl : km/s  km/s V p : 802 km/s  27 km/sσ v : 1057 km/s  658 km/s kT=2.9 keV ABELL MEMBERS CLEAR DETECTION OF SUBSTRUCTURES ALREADY IN MOHR+96 IT HOSTS A MINI RADIO HALO (GITTI+04) PEAK 1 PEAK 2

7 With CF A A A A A A A CENTAURUS 125 A A85 43 A V PEC OF BCGs AND X-RAY STATE NO CF A A A A A A A ESO MKW3S 27 A A

8 V PEC OF BCGs COZIOL+09: “A large fractions of BCGs have significant peculiar velocity. This has one immediate consequence, which is that most clusters harboring a dominant galaxy are not dynamically relaxed” VAN DEN BOSCH+05: “The brightest galaxy in a dark matter halo is expected to reside at rest at the centre of the halo. In this paper, we test this `Central Galaxy Paradigm' (CGP) using group catalogues extracted from the Two-Degree Field Galaxy Redshift Survey (2dFGRS) and the Sloan Digital Sky Survey (SDSS). We show that the CGP is only consistent with the data in haloes with M < M sun, while in more massive haloes the data indicate a non-zero offset between the brightest galaxy and the satellites. This indicates that either central galaxies reside at the minimum of the dark matter potential, but that the halo itself is not yet fully relaxed, or, that the halo is relaxed, but that the central galaxy oscillates in its potential well.

9 V PEC OF BCGs Van den Bosch+05

10 MIRALDA-ESCUDE’+95: “The fact that cD galaxies often have large peculiar velocities relative to the average of the cluster galaxies has been used as an argument against their identification as cluster centers: however, clusters are continuously merging, and their density peaks do not need to coincide with their centers of mass. Substructure will cause the density peaks to move, in response to the gravitational forces of the infalling material” V PEC OF BCGs Abell 383 Richard+11

11 OFF-AXIS MERGERS INDUCING COLD FRONTS CAN EXPLAIN SPEEDING BCGs ALSO IN RELAXED CLUSTERS: NEEDS FURTHER INVESTIGATION TAKING CARE OF POSSIBLE SUBSTRUCTURES PECULIAR VELOCITIES OF BCGs FITS NATURALLY IN A HIERARCHICAL PICTURE OF STRUCTURE FORMATION AND SLOSHING/COLD FRONTS ARE AND X-RAY SIGNATURE SUMMARY

12 V P OF BCGs AND X-RAY STATE NO CORRELATION, NO DIFFERENCE IN THE TWO SUBSAMPLES WITH KS TEST

13 V P OF BCGs AND X-RAY STATE

14 COLD FRONTS AND METALS ANISOTROPIES IN ZW STEFANO ETTORI OBSERVATORY OF BOLOGNA F. GASTALDELLO, M. GITTI, E. O’SULLIVAN, M. GASPARI, F. BRIGHENTI, L. DAVID, A. EDGE

15 ZW

16 ZW : COLD FRONTS

17

18

19 ZW : METAL BAR

20 AGN METAL OUTFLOWS Kirkpatrick+11

21 AGN METAL OUTFLOWS Kirkpatrick+11

22 AGN METAL OUTFLOWS Kirkpatrick+11

23 SLOSHING CAN’T DO IT... Roediger+11

24 ZW : METAL BAR

25 VERY STRUCTURED COLD FRONT IN ZW1742: KH INSTABILITY ANISOTROPY IN THE METAL DISTRIBUTION: AGN MOST LIKELY, HOWEVER CAN SLOSHING DO IT ? SUMMARY


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