SIMBAD references

We characterize the star formation in the low-metallicity galaxy NGC 6822 over the past few hundred million years, using GALEX far-UV (FUV, 1344-1786 Å) and near-UV (NUV, 1771-2831 Å) imaging, and ground-based Hα imaging. From the GALEX FUV image, we define 77 star-forming (SF) regions with area >860 pc², and surface brightness ≲ 26.8 mag (AB) arcsec^–2, within 0°.2 (1.7 kpc) of the center of the galaxy. We estimate the extinction by interstellar dust in each SF region from resolved photometry of the hot stars it contains: E(B - V) ranges from the minimum foreground value of 0.22 mag up to 0.66 ±0.21 mag. The integrated FUV and NUV photometry, compared with stellar population models, yields ages of the SF complexes up to a few hundred Myr, and masses from 2x10² M_☉ to 1.5x10⁶ M_☉. The derived ages and masses strongly depend on the assumed type of interstellar selective extinction, which we find to vary across the galaxy. The total mass of the FUV-defined SF regions translates into an average star formation rate (SFR) of 1.4 x 10^–2 M_☉/yr over the past 100 Myr, and SFR = 1.0x10^–2 M_☉/yr in the most recent 10 Myr. The latter is in agreement with the value that we derive from the Hα luminosity, SFR = 0.008 M_☉/yr. The SFR in the most recent epoch becomes higher if we add the SFR = 0.02 M_☉/yr inferred from far-IR measurements, which trace star formation still embedded in dust (age ≲ a few Myr).