  GRO J2058+42 is a 195 s transient X-ray pulsar discovered in 1995 with BATSE.
In 1996, RXTE located GRO J2058+42 to a 90% confidence error circle with a 4'
radius. On 20 February 2004, the region including the error circle was observed
with Chandra ACIS-I. No X-ray sources were detected within the error circle,
however, 2 faint sources were detected in the ACIS-I field-of-view. We obtained
optical observations of the brightest object, CXOU J205847.5+414637, that had
about 64 X-ray counts and was just 0.3' outside the error circle. The optical
spectrum contained a strong H alpha line and corresponds to an infrared object
in the 2MASS catalog, indicating a Be/X-ray binary system. Pulsations were not
detected in the Chandra observations, but similar flux variations and distance
estimates suggest that CXOU J205847.5+414637 and GRO J2058+42 are the same
object. We present results from the Chandra observation, optical observations,
new and previously unreported RXTE observations, and a reanalysis of a ROSAT
observation.
