MEGATRON

Cosmic breakfast, 2nd breakfast and elevenses challenges

For a better intro
see Zack's presentation

Cosmic breakfast, 2nd breakfast and elevenses challenges

Model [i]

• Based on RAMSES-RT (Rosdahl+13)
• Out-of-equilibrium chemistry (Katz 23)
  Primordial species: \(\text{H~{\small I}-{\small II}}\), \(\text{He~{\small I}-{\small III}}\), \(e^{-}\)
  Metal ions: \(\text{C~{\small I}-{\small VI}}\), \(\text{N~{\small I}-{\small VII}}\), \(\text{O~{\small I}-{\small VIII}}\), \(\text{Ne~{\small I}-{\small X}}\), \(\text{Mg~{\small I}-{\small X}}\), \(\text{Si~{\small I}-{\small XI}}\), \(\text{S~{\small I}-{\small XI}}\) & \(\text{Fe~{\small I}-{\small XI}} \)
  Molecules: \(\text{H}_2\) & \(\text{CO}\)
• Dust model (Rémy-Ruyer+14)
  Assuming dust-to-gass ratio
• Heating & Cooling
  photoheating, photoelectric heating, excitation/dissociation heating, primordial, dust recombination, dust-gas collisions, metal lines
  • \(\text{C~{\small I}}\), \(\text{C~{\small II}}\), \(\text{N~{\small II}}\), \(\text{O~{\small I}}\), \(\text{O~{\small III}}\), \(\text{Ne~{\small II}}\), \(\text{Si~{\small I}}\), \(\text{Si~{\small II}}\), \(\text{S~{\small I}}\), \(\text{Fe~{\small I}}\), \(\text{Fe~{\small II}}\) @ \(T<10^4\,\mathrm{K}\)
  • CLOUDY tables @ \(T>10^4\,\mathrm{K}\)

\(\text{O\small{II}}\)

\(\text{O\small{I}}\)

\(\text{N\small{I}}\)

\(\text{Mg\small{II}}\)

\(\text{Ne\small{II}}\)

\(\text{CO}\)

\(\rho\)

\(v_r\)

\(\text{O\small{III}}\)

Model [ii]

• Turbulence-based star formation (Padoan & Nordlund 11, Agertz+21)
  \(\dot{\rho_\star} = \varepsilon_\star\rho/t_\mathrm{ff}\)
  • if \(Z<10^{-6}Z_\odot\) ⇒ Pop. III
  • if \(Z\geq10^{-6}Z_\odot\) ⇒ Pop. I & II, Kroupa
• \(M_\star = 500\,\mathrm{M}_\odot\)
  \(M_{\star,\rm III} \sim 100\,\mathrm{M}_\odot\)
• Feedback (Agertz+21; Rey+23)
  core-collapse SN, type Ia, winds + HN (Nomoto+06).
• Yields (Limongi & Chieffi 18)
  AGB winds (Ritter+18)

Model [iii]

• MW analogue @ \(z=0\)
• Genetically engineered to form earlier
  ICs generated with genetIC
• 2 main runs
  • constant physical \(\Delta x_\mathrm{min} \approx 20-40\,\mathrm{pc}\)
  • constant comoving \(\Delta x_\mathrm{min}(z=2) = 20\,\mathrm{pc}\)
    \(\Delta x_\mathrm{min}(z=5)=10\,\mathrm{pc}\)
    \(\Delta x_\mathrm{min}(z=14)=4\,\mathrm{pc}\)

Stellar mass vs. Halo mass

CP not too bad compared to Vintergatan (Rey+23)
CC underregulates

Constant comoving

Constant physical

Varying IMF to the rescue?

Same model, but high-\(z\) dwarf \(M_\mathrm{dm}=10^{9}\,\mathrm{M}_\odot\) at \(z=6\)

Pop. III star formation

Pop. III star formation

Cooling length refinment

Refining where

\( \Delta x > 2 \sqrt{\dfrac{P_\mathrm{th}}{\rho}}\times \dfrac{1}{\Lambda_\mathrm{net}},\)

(Rey+23)

• up to \(80\,\mathrm{pc}\)
• turned on at key moments

Cooling length refinment

Refining where

\( \Delta x > 2 \sqrt{\dfrac{P_\mathrm{th}}{\rho}}\times \dfrac{1}{\Lambda_\mathrm{net}},\)

(Rey+23)

• up to \(80\,\mathrm{pc}\)
• turned on at key moments

\(z=5.8\)

\(z=5.8(+2\,\mathrm{Myr})\)

\(20\,\mathrm{kpc}\)

Cooling length refinment

How much does it cost?