The previous post Galactic Corona Radiation did not reference several coincidences present in the spectra taken by an astronomer in 2013, which were in the link.
Among the coincidences are the elements and their velocities.
M31: Calcium, Hydrogen, Magnesium, Sodium; velocity -301 km/s
Aldebaran: Calcium (other elements were not noted but calcium was used for comparing to calcium in M31); +54 km/s (star's velocity is irrelevant here)
NGC 404: Hydrogen, Oxygen; -241 km/s
M33 was too faint for the astronomer so he used NGC 404 as a proxy for M33.
M33 Helio radial velocity-179 km/s
M33 Galactocentric velocity -44 km/s
solar wind: Carbon, Oxygen, others; 250-750 km/s
Coincidences are not a firm basis for a conclusion.
However, this scenario is suggested:
a) these elements in these galactic spectra are from transmutation at the corona's electric discharge,
b) calcium absorption line in Aldebaran is a calcium atom on its photosphere, possibly from transmutation. like a Safire scenario,
c) the M31 calcium could be present by a similar mechanism at the corona,
I could not find the Safire list but I suspect these elements were observed.
d) the NGC 404 oxygen (and emission line) could be present by a similar mechanism,
e) Each atom's velocity comes from the plasma moving away from the discharge (so toward Earth) bringing along neutral atoms,
f) the velocities are similar because the plasma motion at the galactic corona discharge is similar to the plasma at the solar corona discharge, though the solar wind is a different mechanism.
This scenario is most certainly conjecture.
However, the similar velocities among these blue shift objects suggest there is 'something' in common here.
Sometimes, coincidences suggest an explanation.
There are very few blue shifted galaxies; the others:
M90, type Sb, velocity -282 km/s
M98, type SABab, velocity -142 km/s
NGC 6822, type Irregular Bar, velocity -57 km/s
NGC 6822 is an unusual galaxy in the Local Group with just the bar of a spiral galaxy but no arms.
Every blue shift object should have a public spectrum to understand its uniqueness, but they don't, certainly not of their corona.