Astronomical Applications Department, U.S. Naval Observatory thesis Page 41
27
massive star formation extends well beyond the central star forming arc. As indi-
cated by the FUV growth curve of IC2574 in Fig. 3.5, star formation is even less
centrally concentrated than in HoII given that an aperture of half the size of the
entire galaxy only contains
30 of the total integrated FUV ux. The presence
of the large concentration of recent star formation in the northeastern part of
the galaxy is responsible for the the bump" in the pro le at
6
0
. Di erences
between the total integrated ux in apertures smaller than and larger than this
feature indicate that it contributes to
60 of the total integrated FUV ux.
The FUV growth curve of Sextans A in Fig. 3.6 shows that recent massive star
formation is the least centrally concentrated of the three galaxies. For example,
an aperture enclosing the entire galaxy except its corners contains only
30 of
the total integrated FUV ux; the remaining
70 originates from the corners
of the galaxy.
