Public Data Access Overview / Discussion Forum

Hi,

I would like to constrain Fornax-like clusters and all those subhaloes to be consistent with the galaxies present in real Fornax cluster. In essence, I would like to apply observational constrains to TNG50 subhaloes and for so, I'm applying the same 'identification' process as the one performed in Iodice et al. 2019 where they choose targets within 0.7 Mpc of Fornax with mB <= 15. My question is, if I use the field SubhaloStellarPhotometrics to identify all those subhaloes with mB <= 15, will this value be consistent with the observed apparent magnitude or should also apply some zero point or an additional calibration?

Thanks in advance,
Pablo

Hi Pablo,

The GFM_StellarPhotometrics contains (second entry) the Buser "B" band absolute magnitudes in the Vega system. You will likely need to do some conversions to get these to be exactly comparable to your data. Note also these do not model dust in any way.

Hi Dylan,

sorry for my late reply. I was looking into the magnitudes documentation. In principle I could also use the SDSS filters to constrain the apparent magnitudes of my subhaloes. However, what I don't understand is the value of such magnitudes. Are they estimated by assuming a certain distance towards each subhalo? Otherwise, how can a subhalo have apparent magnitudes of about -20? Are they absolute magnitudes?

Thanks in advance,
Pablo

That's correct the GFM_StellarPhotometrics values are absolute magnitudes.

The (k) SDSS Photometry supplementary catalog values are absolute AB magnitudes.

Alright, that makes much more sense.

Thanks very much,
Pablo