The IGM in simulations

Transcription

1 The IGM in simulations Institute for Computational Cosmology Ogden Centre for Fundamental Physics Durham University, UK and University of Antwerp Belgium 1

2 Menu: Simulated DLAs: column density and dynamics The temperature-t relation (redux) 2

3 OWLS project Leiden: Wierma,Van de Voort Chicago HITS ICC-Durham MPE /IAC 3 ICC

4 Star formation Subgrid physics in OWLS Galactic winds AGN feedback Z+J(nu) dependent cooling Stellar evolution 4

5 Track 11 elements that dominate cooling/heating for in photo-ionisation equilibrium with optically thin UV-X-ray background 5

6 Subgrid: the star formation implementation Schaye & Dalla Vecchia, 08 d? dt = f(,t,z,h 2,...) d? dt d / 3/2 But code s density is averaged 6 on kilo-parsecs scales!

7 Subgrid: the star formation implementation (and the origin of the Kennicutt-Schmidt law) Σ SFR Σ n gas (n =1.4 ± 0.15) Local: same galaxy Global: different galaxies Calzetti et al Kennicutt 98

8 Star formation guarantees the simulated galaxies follow the imposed Kennicutt-Schmidt law Schaye 04

9 Subgrid: stellar evolution Assume: stellar initial initial mass function (Chabrier) Assume: stellar lifetimes Assume: luminosities (BC models) Assume: stellar yields Type I SNe Type II SNe AGB stars Few+12, Tornatore+07,Oppenheimer +06,Kawata+13,Scannapieco+09 9

10 Subgrid: SN feedback Supernova feedback expels gas out of galaxy/halo Dark halos (const M/L) galaxies GIMIC simulation 10 Crain+09

11 Galactic winds: stochastic kinetic feedback, no hydrodecoupling, no switching off of cooling At high z: Pettini et al 02 11

12 Z=2 reference model solar mass halo 12

13 Subgrid variations 13

14 Post-processing OWLS for self-shielding to identify DLAs: ray-tracing 14

15 Optically thick gas has tiny cross section. Ray-tracing inefficient 15

16 reverse-ray tracing: start from high density regions: good! Urchin Random sight lines will almost always miss high-density region: bad! Impose optically thin ionising 16 background

17 Urchin can take into account full spectral information. Since know optical depth, can switch from case-a to case-b recombination rate neutral fraction Different spectral shapes depth into 17 slice [kpc]

18 Urchin tests Analytical profile Urchin profile OWLS gas mass HI density total density Ray-tracing spherically-symmetric 18 (stacked) OWLS Tom haloes Theuns

19 Through Thick and Thin - Hi Absorption in Cosmological Simulations Gabriel Altay 1, 1,2, Joop Schaye 3, Neil H. M. Crighton 4,5 and Claudio Dalla Vecchia 3,6 Urchin 8 SPHRAY: A Smoothed Particle Hydrodynamics Ray Tracer for Radiative Transfer Gabriel Altay 1, Rupert A.C. Croft 1, and Inti Pelupessy 1 1 Carnegie Mellon University, Department of Physics, 5000 Forbes Avenue, Pittsburgh PA 15213, USA 19

20 Column-density distribution function co-moving number density of lines owls + urchin log HI column density 20

21 owls = hydrodynamical simulation (Schaye 2010)! urchin = reverse ray-tracer (Altay & TT, 2013) 21

22 22

23 DLAs 23

24 Dependence on physics/numerics (self-shielding, H2 formation, UV-bckg, ) ( ) - LLS and DLA range. In the left panel, we vary the amplitude of the UV ba 24

25 log ratio compared to Ref ISM log HI column 25

26 Outliers Millennium no reionisation no feedback other IMF AGN 26

27 LLS Incidence DLAs 27 cosmology

28 Menu: Simulated DLAs: column density and dynamics The temperature-t relation (redux) 28

29 Rob Perry DLA line widths small DLA big DLA 29

30 Sample DLA - but without the damping wing (!) Si abundance - from simulation SiII/Si = HI/H from Urchin 30

31 31

32 zoomed-in Si2 column density contours 32

33 w i d e l i n e s: velocity structure narrow lines: temperature 33

34 V90 statistics Neeleman (100 DLAs) Owls (1+2 sigma) 34

35 Si II components vs subfind TM structures typical unusual 35

36 Dissected cumulatively in FoF mass 36

37 ratio v90 compared to REF no feedback Millennium no reionisation V90 [km s -1 ] 37

38 Problem? 38

39 Sample DLA - but without the damping wing (!) Si abundance - from simulation SiII/Si = HI/H from Urchin 39

40 Maximum Si II extent ( v100 ) 40

41 Menu: WDM and satellites (to follow Lya WDM) Lya flux PDF (and inverted rho-t relation) Galactic winds Simulated DLAs and LLSs The rho-t relation (redux) 41

42 log temperature log density 42

43 OWLS temperature-density relation 43

44 Line-width Column density 44 b-n from Tom VPfit Theuns

45 1.even narrow lines are broader than (T/m) 1/2 2.what are broader lines: errors? 3.what are narrower lines: errors? metals? Antonella Garzilli thermal broadening 45

46 Don t use VPfit: single max is single absorber (no noise!) 46

47 transmission optical depth Temperature velocity [km s -1 ] 47

48 Use curvature of spectrum to obtain temperature Antonella Garzilli Obtain density from integrating optical depth over the line 48

49 T=100K: still lines have width. Jeans smoothing 49

50 Percentiles Thermal broadening + Jeans smoothing 50

51 ?? 51 line clustering

52 Summary 52