Emission sparks around M 81 and in some dSph galaxies

We use H-alpha images of three clumps of young stars situated between M81 and NGC3077 to estimate their star formation rate. Radial velocities of the clumps measured by us, as well as the velocity of HII-region in the dSph galaxy KDG61 are compatible with their location at the outskirts of a large rotating gaseous disc around M81. In contrast to KDG61, radial velocity of the emission knot in the dSph galaxy DDO44, +213+-25 km/s, tells us that this H-alpha spark belongs to the dSph galaxy itself. F475W and F814W images of DDO44 extracted from the HST archive reveal 8 bluish (B-I < 0.8) stars apparently associated with the H-alpha knot.Comment: 6 pages, 4 figures, accepte

Survey of H-alpha emission from thirty nearby dwarf galaxies

Measurements of the H-alpha flux from 30 neighboring dwarf galaxies are presented. After correction for absorption, these fluxes are used to estimate the star formation rate (SFR). The SFR for 18 of the galaxies according to the H-alpha emission are compared with estimates of the SFR from FUV magnitudes obtained with the GALEX telescope. These are in good agreement over the range log[SFR] = [-3,0]M sun/yr.Comment: 18 pages, 10 figures, 3 table