Evolution of Intrinsic Scatter in the SFR-Stellar Mass Correlation at
  0.5<z<3
  We present estimates of intrinsic scatter in the Star Formation Rate (SFR) -
Stellar Mass (M*) correlation in the redshift range 0.5 < z < 3.0 and in the
mass range 10^7 < M* < 10^11 Msun. We utilize photometry in the Hubble
Ultradeep Field (HUDF12), Ultraviolet Ultra Deep Field (UVUDF) campaigns and
CANDELS/GOODS-S. We estimate SFR, M* from broadband Spectral Energy
Distributions (SEDs) and the best available redshifts. The maximum depth of the
HUDF photometry (F160W 29.9 AB, 5 sigma depth) probes the SFR-M* correlation
down to M* ~ 10 ^7 Msun, a factor of 10-100X lower in M* than previous studies,
and comparable to dwarf galaxies in the local universe. We find the slope of
the SFR-M* relationship to be near unity at all redshifts and the normalization
to decrease with cosmic time. We find a moderate increase in intrinsic scatter
with cosmic time from 0.2 to 0.4 dex across the epoch of peak cosmic star
formation. None of our redshift bins show a statistically significant increase
in intrinsic scatter at low mass. However, it remains possible that intrinsic
scatter increases at low mass on timescales shorter than ~ 100 Myr. Our results
are consistent with a picture of gradual and self-similar assembly of galaxies
across more than three orders of magnitude in stellar mass from as low as 10^7
Msun.
