Table 1.
Parameters and settings of our model.
| Parameter | Description | Prior/Value |
|---|---|---|
| Mh, seed [M⊙] | Minimum mass of the halos that host a seed BH | log𝒰[106, 107.7] |
| fseed | Probability to seed a leaf halo with Mh ≥ Mh, seed at z ≥ 10 | log𝒰[0.01, 1] |
| μseed [M⊙] | Mean of the log-normal distribution of seed masses | log𝒰[102.5, 106] |
| σseed [dex] | Standard deviation of the log-normal distribution of seed masses | log𝒰[100.5, 102] |
| tdelay [Myr] | Additional time delay (after DF timescale) for BH binary merger | log𝒰[10−0.5, 104] |
| tburst [Myr] | Duration of burst accretion mode | log𝒰[1, 100] |
| γburst | Slope of the power-law distribution of fEdd, burst | 𝒰[−1, 0] |
| μsteady [dex] | Mean of the log-normal distribution of fEdd, steady | 𝒰[−6, −3] |
| σsteady [dex] | Standard deviation of the log-normal distribution of fEdd, steady | 𝒰[0.5, 3] |
| zcut | Redshift below which accretion is cut in the most massive BHs | 𝒰[1, 4] |
| mcut, 0 [M⊙] | Mass at z = 0 above which accretion is cut | log𝒰[106, 107.3] |
| αcut | Slope of the increase in the mass cut for accretion with redshift, see Eq. (8) | 𝒰[0, 0.5] |
| fEdd, burst | Burst mode Eddington ratio | 𝒫ℒ(γburst − 1, 10−2, 10) |
| fEdd, steady | Steady mode Eddington ratio | log𝒩(μsteady, σsteady)≤1 |
| tsteady [Myr] | Duration of a steady accretion episode, after which fEdd, steady, tsteady are redrawn | log𝒰[1, 100] |
| ϵ | Radiative efficiency | 0.1 |
| qh, major | Mass ratio threshold for major halo mergers | 0.13 |
| pmulti | Probability of interaction between three or more BHs | 0.22 |
Notes. The first 12 lines (before the double bar) list the free parameters of our model, which we fit to observations. The remaining lines summarise the distributions on quantities entering the simulations and the parameters that are fixed in our model. In the third column, (log) 𝒰 stands for a (log-) uniform distribution in the given range, 𝒫ℒ for a power-law distribution with given slope and range and log𝒩 for a log-normal distribution with given mean and standard deviation.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.