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Hi Dylan, I was calculating the disk fraction of subhalos in TNG50 from scratch, but found that some of my values for DiskFraction differ from the available values in "(c) Stellar Circularities, Angular Momenta, Axis Ratios." I compared the angular momentum, which is fairly consistent, however, DiskFraction shows some scatter. For reference, I have also attached a one-to-one plot. I’ve also included my methods for calculating circularity and disk fraction. Could you help me understand why, for some of the subhalos, the DiskFraction values differ?

def circularity(stellar_specific_angular_momentum,stellar_specific_angular_momentum_z, size=50):
    ji_max_filtered = ndimage.maximum_filter1d(stellar_specific_angular_momentum, size=size, mode="constant")
    circularity = stellar_specific_angular_momentum_z / ji_max_filtered        
    return circularity

def compute_disk_fraction(circularity, mass, threshold=0.7):      
        e_mask = circularity >= threshold
        total_mass = np.sum(mass)
        disk_frac = np.sum(mass[e_mask]) / total_mass
        return disk_frac

I'm sure there are many differences, possibly subtle, between your calculation and the one in that catalog.

One possibility is the use of maximum_filter1d - I don't think this leads to the exact definition of circularity as described.

Ah. Thanks :)