Structure formation and sterile neutrino dark matter

Transcription

1 Structure formation and sterile neutrino dark matter Collaboration: Trujillo-Gomez, Papastergis Merle, Totzauer Aurel Schneider ETH Zurich

2 Dark matter: explore all possibilities DM via annihilation/decay products DM from Collider DM via structure formation Direct detection

3 DM via structure formation

4 DM via structure formation Boltzmann moments :.

5 DM via structure formation Boltzmann moments :. Jeans criterion : Sound speed :

6 DM via structure formation Boltzmann moments :. Negligible Jeans length. Jeans criterion Large Jeans length : Jeans criterion : Sound speed :

7 DM via structure formation Boltzmann moments :. Merle & Schneider (2015) Jeans criterion : Sound speed :

8 Sterile Neutrino Dark Matter: production sterile neutrino

9 Sterile Neutrino Dark Matter: production active neutrino mixing (D&W 1994) sterile neutrino

10 Sterile Neutrino Dark Matter: production active neutrino (S&F 1999) resonant mixing mixing (D&W 1994) sterile neutrino

11 Sterile Neutrino Dark Matter: production some exotic particle active neutrino (S&F 1999) resonant mixing decay mixing (e.g. Kusenko 2006, Merle et al 2013) (D&W 1994) sterile neutrino

12 DM and structure formation: 2 options Constraining sterile neutrino DM Solving problems of structure formation

13 Constraining sterile neutrino DM Milky-Way satellites: Lyman-αforest: Credits: C. Frenk Stolen from: astro.ucla.edu Observed Number of satellites : Transformed into 1D power spectrum Nsat = 63 = classical dwarfs x SDSS dwarfs along line-of-sight

14 Sterile neutrino DM from resonant production

15 Sterile neutrino DM from resonant production X-ray limits: Schneider (2016)

16 Sterile neutrino DM from resonant production Limits from Milky-Way satellite counts: Schneider (2016) Momentum distributions from Venumadhav et al. (2016)

17 Sterile neutrino DM from resonant production Limits from Lyman-αforest : Schneider (2016) Limit corresponds to Viel et al (2013) Momentum distributions from Venumadhav et al. (2016)

18 Sterile neutrino DM from scalar decay production X-ray limits: Merle et al (2016)

19 Sterile neutrino DM from scalar decay production Limits from Milky-Way satellite counts (approximate): FIMP scalar: large mass, small coupling to Higgs portal (see Merle & Totzauer 2015) Momentum distributions from Merle et al. (2016)

20 Sterile neutrino DM from scalar decay production Limits from Lyman-αforest (approximate): Merle et al (2016) Limit corresponds to Viel et al (2013) FIMP scalar: large mass, small coupling to Higgs portal (see Merle & Totzauer 2015) Momentum distributions from Merle et al. (2016)

21 DM and structure formation: 2 options Constraining sterile neutrino DM Solving problems of structure formation

22 Velocity Function: one for all and all for one! Relatively clean probe Field galaxies Good statistics Combination of Over-abundance problem Cusp-core problem TBTF problem

23 Velocity Function: one for all and all for one! Relatively clean probe Field galaxies Good statistics Combination of Over-abundance problem Cusp-core problem TBTF problem Klypin et al. (2015)

24 Velocity Function: connection with BTF Relatively clean probe Field galaxies Good statistics Combination of Over-abundance problem Cusp-core problem TBTF problem Trujillo-Gomez et al. (in prep)

25 Velocity Function: DM-only But wait Theory is DM only!

26 Velocity Function: Max Baryon Depletion But wait Theory is DM only! Need to include baryon feedback : baryon depletion

27 Velocity Function: Max Reionization But wait Theory is DM only! Need to include baryon feedback : baryon depletion reionisation

28 Velocity Function: Max Reionization

29 Velocity Function: Hydro Simulation APOSTLE: Sawala et al 2015, Sales et al 2015

30 Velocity function What about Sterile Neutrino Dark Matter?

31 Warm Dark Matter Strongly suppressed perturbations (at free-streaming scale) Shallower halo profiles Leads to Lower halo abundance Modified vmax

32 Warm Dark Matter Strongly suppressed perturbations (at free-streaming scale) Shallower halo profiles Leads to Lower halo abundance Modified vmax

33 Warm Dark Matter Strongly suppressed perturbations (at free-streaming scale) Shallower halo profiles Leads to Lower halo abundance Modified vmax

34 Warm Dark Matter Strongly suppressed perturbations (at free-streaming scale) Shallower halo profiles Leads to Lower halo abundance Modified vmax

35 Velocity function and resonant production Limits from Lyman-αforest : Schneider et al (in prep)

36 Velocity function and resonant production Limits from Lyman-αforest : Schneider et al (in prep) theory agrees with observations

37 Velocity function and scalar decay production Limits from Lyman-αforest (approximate): Schneider et al (in prep)

38 Velocity function and scalar decay production Limits from Lyman-αforest (approximate): theory agrees with observations Schneider et al (in prep)

39 Conclusions : Sterile neutrino DM: A better match observations from local galaxies resonant production: in trouble! scalar decay production: fne! Aurel Schneider ETH Zurich

40 Profile fitting