Spatially Resolved Star Formation History Along the Disk of M82 Using
  Multi-Band Photometric Data
  We present the results on the star formation history and extinction in the
disk of M82 over spatial scales of 10" (~180 pc). Multi-band photometric data
covering from the far ultraviolet to the near infrared bands were fitted to a
grid of synthetic spectral energy distributions. We obtained distribution
functions of age and extinction for each of the 117 apertures analyzed, taking
into account observational errors through Monte-Carlo simulations. These
distribution functions were fitted with gaussian functions to obtain the mean
ages and extinctions along with errors on them. The analyzed zones include the
high surface brightness complexes defined by O'Connell & Mangano (1978). We
found that these complexes share the same star formation history and extinction
as the field stellar populations in the disk. There is an indication that the
stellar populations are marginally older at the outer disk (450 Myr at ~3 kpc)
as compared to the inner disk (100 Myr at 0.5 kpc). For the nuclear regions
(radius less than 500 pc), we obtained an age of less than 10 Myr. The results
obtained in this work are consistent with the idea that the 0.5-3 kpc part of
the disk of M82 formed around 90% of the stellar mass in a star-forming episode
that started around 450 Myr ago lasting for about 350 Myr. We found that field
stars are the major contributors to the flux over the spatial scales analyzed
in this study, with stellar cluster contribution being 7% in the nucleus and
0.7% in the disk.
