H-alpha survey of low-mass satellites of the neighbouring galaxies M31
  and M81
  Images have been obtained at the 6-m telescope at the Special Astrophysical
Observatory (SAO) of the Russian Academy of Sciences in the H-alpha line and in
the continuum for 20 dwarf spheroidal satellites of M31: And XI-And XXX, plus
the distant Globular cluster Bol 520. Their star formation rates (FR) are
estimated using the H-alpha flux and the ultraviolet FUV flux measured with the
GALEX space telescope. Most of the dSph satellites of M31 have extremely low
star formation rates with a characteristic upper limit of SFR~5x10^{-7}. We
have made similar estimates of SFR from the H-alpha and FUV fluxes for 13
galaxies with low surface brightness recently discovered in the neighborhood of
M81. Eleven of them are physical satellites of M81 with typical SFR< 5x10^{-5}.
The median stellar masses of these satellites of M31 and M81 are 0.9 and 1.9
million solar masses, respectively. Our H-alpha observations place a 2-3 times
stricter limit on the value of SFR than the data from the GALEX satellite, with
a substantially higher (3-5 times) angular resolution.
