Star Formation History in TNG100 wrt Time Resolution
Siddharth Dutta
26 May
Hello
I would like to construct the Star Formation History of each subhalo in the TNG100-1 simulation. However, I must have the histogram in 1 Myr intervals.
Now, there are many subhalos with very few star particles that do not allow the generation of accurate SFH.
Could you kindly advise on the best way of generating SFH for the subhalos. Also, does TNG star formation have a resolution of 1 Myr such that the generated SFH is physically accurate?
Thank You.
Dylan Nelson
27 May
If you calculate SFHs as the histogram of the ages of the member star particles, then yes there is plenty of time resolution to do so in 1 Myr time bins.
However, the need to create an integer number of star particles i.e. at least one at TNG100-1 mass resolution (1e6 Msun) means that there will be some minimum "resolvable" amount of SFR using this technique. You can see related discussion in Donnari, M. et al. papers.
If a subhalo has very few stars, then by definition its SFH over most of cosmic time is zero, for any binning. Near SFR episodes, individual star particle creation may look like delta functions at 1 Myr time resolution. This may be physically correct, or perhaps in reality that amount of star formation would have occurred over a somewhat longer time period.
To get a sense of these effects, you could compare to SFHs from TNG50-1 for similar mass subhalos.
Hello
I would like to construct the Star Formation History of each subhalo in the TNG100-1 simulation. However, I must have the histogram in 1 Myr intervals.
Now, there are many subhalos with very few star particles that do not allow the generation of accurate SFH.
Could you kindly advise on the best way of generating SFH for the subhalos. Also, does TNG star formation have a resolution of 1 Myr such that the generated SFH is physically accurate?
Thank You.
If you calculate SFHs as the histogram of the ages of the member star particles, then yes there is plenty of time resolution to do so in 1 Myr time bins.
However, the need to create an integer number of star particles i.e. at least one at TNG100-1 mass resolution (1e6 Msun) means that there will be some minimum "resolvable" amount of SFR using this technique. You can see related discussion in Donnari, M. et al. papers.
If a subhalo has very few stars, then by definition its SFH over most of cosmic time is zero, for any binning. Near SFR episodes, individual star particle creation may look like delta functions at 1 Myr time resolution. This may be physically correct, or perhaps in reality that amount of star formation would have occurred over a somewhat longer time period.
To get a sense of these effects, you could compare to SFHs from TNG50-1 for similar mass subhalos.