Centimetre continuum emission from young stellar objects in Cederblad 110

¹ Observatory, Tähtitorninmäki, PO Box 14, 00014, University of Helsinki, Finland
² Department of Astronomy, 215 Space Sciences Building, Cornell University, Ithaca, NY 14853-6801, USA

Corresponding author: K. Lehtinen, kimmo.lehtinen@helsinki.fi

Received: 23 December 2002
Accepted: 31 January 2003

Abstract

The low-mass star formation region associated with the reflection nebula Cederblad 110 in the Chamaeleon I cloud was mapped with the Australian Telescope Compact Array (ATCA) at 6 and 3.5 cm. Altogether 11 sources were detected, three of which are previously known low mass young stellar objects associated with the nebula: the illuminating star IRS 2 (Class III, Einstein X-ray source CHX 7), the brightest far-infrared source IRS 4 (Class I), and the weak X-ray source CHX10a (Class III). The other young stellar objects in the region, including the Class 0 protostar candidate Cha-MMS1, were not detected. The radio spectral index of IRS 4 () is consistent with optically thick free-free emission arising from a dense ionized region, probably a jet-induced shock occurring in the circumstellar material. As the only Class I protostar with a “thermal jet” IRS 4 is the strongest candidate for the central source of the molecular outflow found previously in the region. The emission from IRS 2 has a flat spectrum () but shows no sign of polarization, and therefore its origin is likely to be optically thin free-free emission either from ionized wind or a collimated jet. The strongest source detected in this survey is a new compact object with a steep negative spectral index (-1.1) and a weak linear polarization (~), which probably represents a background radio galaxy.