SURFACE BRIGHTNESS OF STARBURSTS AT LOW AND HIGH REDSHIFTS

Observations in the rest-frame ultraviolet from various space missions are used to define the nearby starburst regions having the highest su rface brightness on scales of several hundred parsecs. The bright limi t is found to be 6 x 10(-16) ergs cm(-2) s(-1) Angstrom(-1) arcsec(-2) for rest-frame wavelength of 1830 Angstrom. Surface brightness in the brightest pixel is measured for 18 galaxies in the Hubble Deep Field having z > 2.2. After correcting for cosmological dimming, we find tha t the high-redshift starbursts have intrinsic ultraviolet surface brig htness that is typically 4 times brighter than low-redshift starbursts . It is not possible to conclude whether this difference is caused by decreased dust obscuration in the high-redshift starburst regions or b y intrinsically more intense star formation. Surface brightness enhanc ement of starburst regions may be the primary factor for explaining th e observed increase with redshift of the ultraviolet luminosity arisin g from star formation.