A photodissociated region associated with the compact H II region near GGD12-15

We present Very Large Array (VLA) continuum (2, 3.6, and 20 cm) and line (H I 21 cm, C92 alpha, and H92 alpha) observations toward the obscured cometa ry-like H II region located near the optical nebulosities GGD 12-15. We fin d that the H92 alpha recombination line profile is asymmetric, probably due to a superposition of line emission from the H II region and from an under lying partially ionized medium (H-0). The observed kinematics of the ionize d gas suggests that the H II region is undergoing a champagne flow. The C92 a observations show that the C+ emission arises from an extended region of similar to 20 " in size that is closely associated with the H II region. Th e C+ emission has a line center velocity of 11.9 km s(-1) similar to the ve locity of the ambient molecular cloud (similar to 11 km s(-1)). The 21 cm H I spectrum shows emission and absorption line components. The H I line in emission is detected from a region of similar to 23 " in diameter, with a c enter velocity of 15.4 km s(-1) and peaks to the east of the H II region. T he absorption feature is unresolved (less than or equal to 22 "), has a lin e center velocity of 11.7 km s(-1) and lies in front of the H II region. Bo th the C92 alpha and H I emissions are interpreted as arising from a photod issociated region (PDR) around the cometary H II. region. An isothermal mod el has been used to derive the physical parameters of the photodissociated hydrogen gas around the H rr region. We derive that the PDR region has an e xcitation temperature of similar to 330 K, a hydrogen column density of sim ilar to 6 x 10(21) cm(-2), a H I number density of similar to 1.5 x 10(4) c m(-3), and a H I mass of similar to 5 M.. The mass in photodissociated hydr ogen is about 3 orders of magnitude larger than the mass in ionized hydroge n (similar to 2 x 10(-3) M.).