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Formation of intergroup and intragroup objects Kenji Bekki (UNSW) Origin of isolated massive clouds, intergalactic HII regions, intragroup GCs etc….

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Presentation on theme: "Formation of intergroup and intragroup objects Kenji Bekki (UNSW) Origin of isolated massive clouds, intergalactic HII regions, intragroup GCs etc…."— Presentation transcript:

1 Formation of intergroup and intragroup objects Kenji Bekki (UNSW) Origin of isolated massive clouds, intergalactic HII regions, intragroup GCs etc….

2 Today’s topic Formation of intragroup HI gas, rings, and HII regions (Bekki, Koribalski, Kilborn, Ryan-Weber, Ryder, Couch, etc…). Evolution of compact group of galaxies (my old studies). Formation of intergroup and intragroup GCs (with Yahagi).

3 Formation of intracluster/intercluster (group) GCs. (Yahagi & Bekki 2005) The large-scale structure of MPCs (MPC=Metal-poor globular cluster)

4 Evolution of extended gas disks in high M/L galaxies. NGC 2915 (Meurer et al. 1996) gas stars R HI /R OPT ~ 2.0 gas

5 Three roles of galaxy interaction and galaxy- group interaction Morphological transformation (e.g., Sp  SB) Triggering starbursts and AGNs (+ GC formation). Formation of intragroup stellar and gaseous (e.g., isolated HI gas, drifting GCs).

6 Origin of intragroup HI (e.g., recent HIPASS results) (1) Intergalactic rings.(2)IntragroupHI (NGC 2442) Ryan-Weber et al. (2002) Ryder et al. (2002)

7 Dynamical fate of stripped gas in groups Formation of isolated HI gas around NGC 2442 (Bekki, Koribalski, Ryder, & Couch 2005) ``Dark galaxy formation’’ (Bekki, Kilborn, & Koribalski 2005). Intragroup HII regions from tidal compression of HI clouds (Bekki & Ryan-Weber 2005).

8 Formation of intragroup HI rings (Bekki et al. 2004) GasStars

9 HI ring formation from a LSB

10 (A) Simulation. (B) Observation

11 Dependence of HI morphology on detection limit cm -2 4*10 18 cm -2 2*10 19 cm -2  N(HI) thres =

12 ``Dark HI galaxy’’ in the Virgo cluster (Minchin et al. 2005)

13 ``Dark HI galaxy’’ as tidal derbis (Bekki et al. 2005)

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17 2D velocity fields of simulated ``dark HI clouds’’. Isolated disk

18 Intragroup HII regions around NGC 1533 in the Dorado group (Ryan-Weber et al. 2004)

19 NGC 1533 center HI disk Formation of intragroup HII region from tidal compression.  thres = 3 M solar /pc 2

20 Gas New stars Formation of Stars within Stripped HI (Bekki et al. 2005)

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25 Other objects: NGC 1490 (Oosterloo et al. 2004) Gemini GMOS observations by de Oliveira et al. (2004)

26 Evolution of compact groups into field Es (Barnes 1989)

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28 MRC (Meta-rich GC) MPC(Metal-poor GC)

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30 How can we prove figure rotation of Es from GC kinematics ?

31 Multiple starbursts in multiple mergers (Bekki 2001)

32 Formation of starburst/AGN in collapasing CGs ? HST morphologies of ULIRGs.

33 Tidal stripping and common (metal-poor) gaseous halos Outer disk Inner disk

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36 Transformation from spiral-rich groups with no intragroup gas into E-dominated ones with intragroup HI (also with spiral companion). Possible candidate of HI ?

37 ``Selective stripping’’ of outer parts of galaxies in CGs. Formation of common HI envelopes in CGs ? Formation of metal-poor stellar halos (or hot metal-poor X-ray gas) after E formation ? A new clue of ``E+A’’s environments (2dF, 6dF, SDSS etc….e.g., the origin of E+As with companion galaxies)

38 Formation of intergroup GCs. (Yahagi & Bekki 2005) The large-scale structure of MPCs (MPC=Metal-poor globular cluster)

39 (Yahagi & Bekki 2005: Bekki & Yahagi 2005) INGC: Intergroup (intercluster, intergalaxy) GCs that are not within any virialized halos. INGC HGC HGC: GCs that are within virialized halos.

40 Distance (mass) of the closest neighbor halos. R nei M nei

41 Predictions of INGC properties. (1)~ 100 INGCs / Mpc 3. (2)More metal-poor, slightly younger than those HGC (i.e.., GCs within halos). (3)Immune from GC destruction by galaxy-scale tidal fields: Do they retain fossil information on initial cluster MF ?

42 Conclusions. (1)Stripped HI as intragroup HI objects (e.g. isolated clouds, rings, ``dark galaxy’’ etc). (2)Metal-poor stellar/gaseous halo formation after transformation from CGs to Es. (3)Formation of intergroup/intercluster GCs in the hierarchical clustering scenario.

43 Formation of young star clusters (super star clusters) in interaction/merging galaxies. (SSC: M v <-10, size <15pc)

44 Basic components of a galaxy Globular clusters (GC) Dark matter halo Bulge Disk (thin + thick) Stellar halo

45 Conclusions. (1)Stripped HI as intragroup HI objects (e.g. isolated clouds, rings, ``dark galaxy’’ etc). (2)Metal-poor stellar/gaseous halo formation after transformation from CGs to Es. (3)Formation of intergroup/intercluster GCs in the hierarchical clustering scenario.


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