Abstract
We present sensitive VLA observations at 3.6 cm of nine fields containing Herbig-Haro objects. In 7 out of the 9 observed fields we detect radio sources inside the error ellipsoid of the IRAS source that is believed to be exciting the outflow: HH 366 in B5, HH 300 in B18w, HH 192 in L1527, HH 83 in L1641, HH 117 in L1598, HH 124 near NGC 2264, and HH 375 in L1157. These radio sources are quite likely thermal jets produced by the stars that excite the region. In the case of IRAS 04368+2557 we made a map of higher angular resolution at 2 cm that shows that the source is elongated in the direction of the molecular outflow in the region, confirming its nature as a thermal jet. For two flows, HH 376 in L1152 and HH 363 in L1221, we did not detect any radio source coinciding with the infrared driving source. When these results are combined with previous sensitive observations, we conclude that most HH energy sources can be detected at 3.6 cm in surveys reaching rms noise levels of about 20 μJy.
