Two galactic spectrums nearly identical?

Why are the spectrum for these two galaxies nearly identical? I’ve never seen spectra line up like this, but I don’t know too much !

Dunno, two galaxies at the same redshift and in the same environment will look pretty similar I guess. If you look at the rightmost of the pair down and to the right of these ones, it’s also very similar.

Thanks Dustin, I think you’re right, sorry for crying wolf. (Next time I’ll try and cry wolf-rayet instead… :wink: ) It seems that generally if the galaxy is the same type, it has basically the same spectra at the same redshift (if in the same area). I tested this with three other passiveish… non-blue galaxies at .023… and yeah very similar too, sorry again

Is there any way I can filter the SDSS objects by redshift and do data analytics on like (all things at above a certain redshift), say if I wanted to investigate the spectra of quasars? (it is okay if not I’m just wondering) Also, though sometimes the end of the spectrum looks different - but that is noise you would say? Why is there often noise in the flux at the high end again around 9000 angstrom?

At the long-frequency end of the spectrum, we start to get a bunch of water vapour (OH) lines from the atmosphere.

SDSS has a ton of different tools for accessing their data.
Here’s one entry point…