Abstract

NERIA, Citlali; GOMEZ, Yolanda  and  RODRIGUEZ, Luis F. Compact radio sources in the vicinity of the ultracompact HII region G78.4+2.6. Rev. mex. astron. astrofis [online]. 2010, vol.46, n.2, pp.253-263. ISSN 0185-1101.

Using the Very Large Array (VLA) at 3.6 cm we identify four new compact radio sources in the vicinity of the cometary HII region G78.4+2.6 (VLA 1). The four compact radio sources (named VLA 2 to VLA 5), have near-infrared counter-parts, as seen in the 3.6 µm Spitzer image. One of them (VLA 5) clearly shows evidence of radio variability in a timescale of hours. We explore the possibility that these radio sources are associated with pre-main sequence (PMS) stars in the vicinity of the UC HII region G78.4+2.6. Our results favor the smaller distance value of 1.7 kpc for G78.4+2.6. In addition to the detection of the radio sources in the vicinity of G78.4+2.6, we detected another group of five sources which appear located about 3' to the northwest of the HII region. Some of them exhibit extended emission.

Keywords : HII regions; ISM [individual (G78.4+2.6, IRAS 20178+4046)]; radio continuum [stars].