I have downloaded the PartType4 (stars/wind particles) HDF5 file using the API and am attempting to calculate the ages of a Subhalo's gas particles at redshift z=1. However, I've encountered a significant number of negative values (-0.140808) for the 'GFM_StellarFormationTime' field. And some values are larger than 0.5 (at z=1). According to the field's description, which states it is 'The exact time (given as the scale factor) when this star was formed,' I would expect it to be non-negative. Is it appropriate for me to manually adjust these outlier values to 0.000001 (0.5 when z=1)?
Thank you for you attention.
Morris Su
16 Aug
Oh, I have figured out that the negative values represent wind particles, and the values larger than 0.5 are due to my not having taken the precise redshift into account. The precise redshift of the snapshot at z=1 is 0.99729422578194, thus the scale factor a is 0.50067735. Q.E.D.
Hi,
I have downloaded the PartType4 (stars/wind particles) HDF5 file using the API and am attempting to calculate the ages of a Subhalo's gas particles at redshift z=1. However, I've encountered a significant number of negative values (-0.140808) for the 'GFM_StellarFormationTime' field. And some values are larger than 0.5 (at z=1). According to the field's description, which states it is 'The exact time (given as the scale factor) when this star was formed,' I would expect it to be non-negative. Is it appropriate for me to manually adjust these outlier values to 0.000001 (0.5 when z=1)?
Thank you for you attention.
Oh, I have figured out that the negative values represent wind particles, and the values larger than 0.5 are due to my not having taken the precise redshift into account. The precise redshift of the snapshot at z=1 is 0.99729422578194, thus the scale factor a is 0.50067735. Q.E.D.