Viewing angles used in "SDSS Photometry, Colors, and Mock Fiber Spectra" data catalogs

Andrej Obuljen
  • 27 Aug '20


A quick question about the viewing angles in the "SDSS Photometry, Colors, and Mock Fiber Spectra" data catalog, for TNG100-1.

Are the viewing angles same for all the galaxies and is there a quick way I can get these viewing angles?

As far as I understood, these angles correspond to HEALPix Nside=1 pixel centers, but I guess there are a couple of ways that one can orient and order the pixels, so I would just like to be sure that I get it right.

Thanks and bests,
Andrej Obuljen

Dylan Nelson
  • 1 Sep '20

Hi Andrej,

In the actual HDF5 file, for the main dataset, there are several metadata attributes. You can see all these with e.g. h5ls -rv stellar_photometry.99.hdf5. The nProj and in particular projVecs contain the 3-vectors of the twelve directions. These are in the frame of reference of the simulation coordinates. (They are the same as the unmodified healpix Nside=1 points, as you say).

Andrej Obuljen
  • 1 Sep '20

Thanks a lot Dylan!


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