Simula'ng*Self-Interac'ng* Dark*Ma5er* - PowerPoint PPT Presentation

Simula'ng*Self-Interac'ng* Dark*Ma5er* Andrew*Robertson*(Durham*University)* Supervisors:*Richard*Massey,*Vincent*Eke*and* Richard*Bower* 9 th *June*2014,*DMUK*Mee'ng,*Durham*

What*is*Self-Interac'ng*Dark*Ma5er?* Dark*Ma5er*that*is*strongly*coupled*to*itself.* • Natural*in*models*with*a*rich*dark*sector*which*has*new*gauge*forces.* • Examples*include:* • - “Dark*Electromagne'sm”*(Ackerman*et*al.*2006)* - “Fluid*Dark*Ma5er”*(Peebles,*2000)** - “Q-balls”*(Kusenko*and*Steinhardt,*2001)* - “Light*Asymmetric*Dark*Ma5er”*(Frandsen*et*al.*2011)* DM* DM* DM* DM*

Astrophysical*Consequences* Core-Cusp*(Weinberg*et*al.*2013)* Too*Big*to*Fail* Missing*Satellites*(Klypin*et*al.*1999)* Garrison-Kimmel*et*al.*2014*

Modified*G ADGET -2* (Springel,*2005)* What*is*G ADGET -2*?* • - “Freely*available*code*for*cosmological*N-body/SPH*simula'ons*on*massively*parallel* computers”* - Computes*gravita'onal*forces*using*a*hierarchical*tree*algorithm*for*short-range*forces*and*a* par'cle*mesh*on*large*scales.* Γ = dn d 3 v 1 • Sca5ering*rate*given*by:* ∫ ( ) ρσ DM v 0 − v 1 f v 1 dt = ij = σ DM v i − v j Δ t • Probability*of*par'cle*i*sca5ering*from*par'cle*j,*in*'me*Δt*is:* P 3 h 3 4 π Tests*of*Sca5ering*Kinema'cs*

( ) M σ ˆ m σ = a 2

Major*Mergers* Clowe*et*al.*2006* Bradac*et*al.*2008* Jee*et*al.*2012* Clowe*et*al.*2013* Kahlhoefer*et*al.*2014* Merten*et*al.*2011*

Minor*Mergers:*“Bulle'city”* Harvey*et*al.*2014*

Kahlhoefer*et*al.*2014*

Thanks*for*listening*