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Mathieu PUECH GEPI Observatoire de Paris

Rebuilding discs with gas-rich major merger. Mathieu PUECH GEPI Observatoire de Paris. , R. Delgado, M. Rodrigues, S. Fouquet. + J.L. Wang, L. Athanassoula, P. Hopkins. ESO 3D2014 – March 2014. 72% of local galaxies are spiral. M stellar > 2x10 10 M o. NGC 2997. NGC 1365.

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Mathieu PUECH GEPI Observatoire de Paris

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  1. Rebuilding discs with gas-rich major merger Mathieu PUECH GEPI Observatoire de Paris , R. Delgado, M. Rodrigues, S. Fouquet + J.L. Wang, L. Athanassoula, P. Hopkins ESO 3D2014 – March 2014

  2. 72% of local galaxies are spiral Mstellar > 2x1010 Mo NGC 2997 NGC 1365 M100 SABbc M 31 M83

  3. 3D Spectroscopy VLT/FLAMES-GIRAFFE (R~10000, 8-24hrs exposure) Imaging ACS images (≥ 3 orbits) Integrated spectroscopy VLT/FORS2 (600RI+600z) (≥ 3 hrs each) Multi-λ photometry Spitzer, GALEX, ACS, EIS,etc. The IMAGES survey Sample selection MJ < -20.3 & 0.4 < z < 0.9 4 fields, including the CDFS Intermediate-mass galaxies Mstellar > 1.5x1010Mʘ Likeliest progenitors of present-day ~M* spirals, six billion years ago SF sub-sample EW0([OII])>15 Å 0.4 < z < 0.75

  4. Representativity LF, z=0.5 Pozzetti+03 LF, z=1.0 z=0.45-0.7 SFR-M* Sequence from Noeske+07;Dutton+10 Yang+08 IMAGES = representative sample of 63 M* galaxies selected in 4 different fields of view (unbiased by cosmic variance)

  5. Half of z~0.6 spirals had peculiar morphologies Delgado-Serrano+10

  6. 95% of CK are M, or Pec/M-T 86% of PR are M, or Pec/M-T 80% of RD are Sp Morpho-kinematic classification Neichel+08 Anomalous kinematics of the ionized gas is linked to anomalous morphological distribution of the stars 50% of intermediate-mass galaxies at z~0.6 are not relaxed morphologically OR kinematically Hammer+09b

  7. Associating Morpho-kinematics with physical processes COLD STREAMS CLUMP FRAGMENT. MAJOR MERGERS MINOR MERGERS SECULAR EVOLUTION OUTFLOWS

  8. Associating Morpho-kinematics with physical processes 20 % of z~0.6 M* galaxies 10 % of rotators (Puech10) COLD STREAMS CLUMP FRAGMENT. MAJOR MERGERS MINOR MERGERS SECULAR EVOLUTION OUTFLOWS

  9. Associating Morpho-kinematics with physical processes 20 % of z~0.6 M* galaxies 10 % of rotators (Puech10) COLD STREAMS CLUMP FRAGMENT. MAJOR MERGERS <8 % of z~0.6 M* galaxies (Rodrigues+12) MINOR MERGERS SECULAR EVOLUTION OUTFLOWS

  10. Associating Morpho-kinematics with physical processes 20 % of z~0.6 M* galaxies 10 % of rotators (Puech10) COLD STREAMS CLUMP FRAGMENT. MAJOR MERGERS GIRAFFU IFU resolution ~ 7 kpc @ z=0.6 (Puech+07,12) <8 % of z~0.6 M* galaxies (Rodrigues+12) MINOR MERGERS SECULAR EVOLUTION OUTFLOWS

  11. Associating Morpho-kinematics with physical processes Cold flows ↘ (Keres+09,Nelson+13) Kinematic imprint too weak (Hopkins+10;Puech+12) 20 % of z~0.6 M* galaxies 10 % of rotators (Puech10) COLD STREAMS CLUMP FRAGMENT. MAJOR MERGERS GIRAFFU IFU resolution ~ 7 kpc @ z=0.6 (Puech+07,12) <8 % of z~0.6 M* galaxies (Rodrigues+12) MINOR MERGERS SECULAR EVOLUTION OUTFLOWS

  12. Associating Morpho-kinematics with physical processes Cold flows ↘ (Keres+09,Nelson+13) Kinematic imprint too weak (Hopkins+10;Puech+12) 20 % of z~0.6 M* galaxies 10 % of rotators (Puech10) COLD STREAMS CLUMP FRAGMENT. MAJOR MERGERS Kinematic imprint too weak (Hopkins+10;Puech+12) GIRAFFU IFU resolution ~ 7 kpc @ z=0.6 (Puech+07,12) <8 % of z~0.6 M* galaxies (Rodrigues+12) MINOR MERGERS SECULAR EVOLUTION OUTFLOWS

  13. 18/27 non (or semi-)relaxed galaxies have « secured » merger models (ZENO or GADGET2 codes) Hammer et al. 2009b

  14. When (the best) model matches the observations Dating the observation time Time Beginning of the simulation Time Peirani et al. 2009

  15. Gas compression phases are well constrained and consistant with expectations Puech+12

  16. Merger rate: observations vs. theory Theory (Hopkins' semi-empirical model) μbaryon≥ 0.25 and Mbaryon=1010.2-1011 M⊙ Impact of possible systematics from Mstellar measurements on theoretical predictions • Observations (IMAGES) Puech, Hammer, Hopkins et al. (2012) See also Lopez-Sanjuan+13 (MASSIV) The apparent large occurrence (~33%) of merger features in z~0.6 galaxies is due to the large visibility timescale of the morpho-kinematic observations (~1.8 Gyr in the pre-fusion phase and post-fusion phases).

  17. Properties of the IMAGES merger progenitors Rodrigues+12 Hammer et al. 2009b z=2, Erb+06 z=2, Erb+06 z=1.5, Daddi+10 z=0.6, IMAGES z=2, Tacconi+10 z=1, Tacconi+10 z=0 ; Schiminovich08 z=0 ; GASS survey Reformation of a significant disk expected after such gas-rich major mergers (Hopkins+09-12 ; Keres+12 w/ AREPO)

  18. Rodrigues+12 Gas fraction (%) Lookback time (Gyr) Semi-empirical models with gas-rich mergers + IMAGES Hopkins et al 2010 Hopkins+10 See also cosmological simulations: Keres+12; Guedes+11, Font+11, Brook+11, Aumer+13 and others Hopkins et al. (2009-2011)

  19. Main sequence of SFGs & major mergers Cox+08 0.3 dex Duty cycle: 0.4-2.5 Gyr (1-2 s) Individual major mergers: Small SFR peak duration Tension between the SFR peak duration and the duty cycle of major mergers (Noeske+07)?

  20. Main sequence of SFGs & major mergers Cox+08 0.3 dex Duty cycle: 0.4-2.5 Gyr (1-2 s) Average: much larger SFR peak duration Duty cycle is statistical: need to consider the average SFR peak duration in an representative sample!

  21. Main sequence of SFGs & major mergers 1.8 Gyr 0.3 dex Duty cycle: 0.4-2.5 Gyr (1-2 s) No contradiction between duration of the average SFR peak and major merger duty cycle (Noeske+07)

  22. SFR fraction associated to mergers ±5% ≈ Morphologically-selected mergers Consistent with Robaina+09: 15-21% (see also Jogee+09)

  23. SFR fraction associated to mergers SFR enhancement Consistent with Robaina+09: 8±3% (see also Jogee+09)

  24. SFR fraction associated to mergers Total SFR fraction associated to major mergers: 53-88%

  25. Conclusions • Morpho-kinematic observations are sensitive to all the phases of the major merger process • The observed major (μbaryon≥ 0.25) in Mstellar=1010-1011 M⊙ is found to be in very good agreement with theoretical predictions, without any fine-tuning • 33 % of all z~0.6 interm.-mass galaxies are on-going major mergers, which show strong kinematic and morphological perturbations. 50 % of local galaxies have undergone a major merger since z=1.5 (see also MASSIV results). • There is no tension between these fractions and the Main Sequence of star-forming galaxies, the fraction of local bulgeless galaxies (B/T < 0.2, Puech+12), or the fraction of LIRGs • Such mergers should on average produce bulge galaxies with a significant disk. Simulated examples: M31 (Hammer+10), NGC5907 (Wang+12).

  26. Example of NGC 5907 Best models : 1:3 to 1:5 major mergers with fgas=60-80% in the progenitors Optical vs. IR/Spitzer: MartinezDelgado+08 26 IRAC Wang+12

  27. Extras

  28. Observing galaxy evolution MASSIV DYNAMO +zC-SINF Adapted from Contini+11

  29. Kinematic Classification FLAMES-GIRAFFE 3D spectroscopy Sample Gal. Population ● RD 20% 32% Flores+06 Puech+06a Yang+07 +/- (<)12% (upper limit: Kutdemir+08,10) ■ PR 16% 25% ▲ CK 27% 43% HST VF σ S/N VF-model σ−model ● RD ■ PR ? ? ▲ CK

  30. GIRAFFU IFU resolution ~ 7 kpc @ z=0.6 Associating Morpho-kinematics with physical processes CK galaxies: Morpho-kinematic disturbances are global, not local: Puech et al. (2007)

  31. Clumpy galaxies in IMAGES Puech (2010) They represent only ~20% of z~0.6, intermediate-mass galaxies @ z>1 (Elmegreen+05)

  32. Clumpy galaxies in IMAGES Half of them are rotators (RD or PR) as expected in clumpy galaxies (Bournaud et al. 2007, 2008).

  33. The standard picture of galaxy formation: Recent developments Gas is not necessarly shock-heated at the Virial Radius: Streams of cold gas entering massive haloes Binney 1977 Birnboim & Dekel 2003 Keres et al. 2005 Dekel & Birnboim 2006 Dekel et al. 2009 Keres et al. 2009 Spherical cold gas accretion

  34. Cold streams at z~0.6 shocked « Clumpy » Brooks+09 Unshocked z~0.6 Cold gas accretion tends to vanish in massive halos at z<1 (<1.5 Mo/yr at z~0.6, see Keres et al. 2009, Brooks et al. 2009): Puech (2010)

  35. Global perturbations Hopkins et al. (2010) Puech, Hammer, Hopkins et al. (2012) Merger rate Time-scale amplification for internal or external global perturbations Accretion rate Perturbation/merger Secular IMAGES Rotators: Kinematic perturbations are too strong to be associated to accretion or internal perturbations

  36. Associating Morpho-kinematics with physical processes Only a handful of galaxies have significant shifts between abs. and emission lines (Puech10; Rodrigues+12). ~162km/s Hβ [NeIII] HeI Integrated FORS2 spectroscopy

  37. ObservingLSB material hardly detectable above z~0.5-1 Absence of tidail tails, shells, etc. is not an evidence of an absence of merger above z~0.5-1 Barden et al. (2009)

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