Extended soft x-ray source in Delphinus: H2027+19

We report the detection of an extended (approx.30) source of soft X-ray emission. H2027+19, observed with the HEAO 1 A-2 experiment. The object emits primarily in the 0.16--0.4 keV band, with a total flux in this band of approx.2 x 10-11 ergs cm-2 S-1. Although our data can be formally modeled with two discrete sources, a detailed analysis suggests that this alternative is not likely to be the case. We fine that both simple continuum and coronal plasma models provide good fits to the observed pulse-height spectrum. The source parameters are restricted to 10/sup 5.8/ <T<10/sup 6.5/K, N/sub x/<10/sup 21.3/ cm-2 (Raymond and Smith plasma), and 10/sup 5.8/<T<10/sup 7.0/, N/sub x/<10/sup 21.2/ (exponential+Gaunt factor) at the 90% confidence level. The most likely physical models are either that the source is an old supernova remnant or that it is a region of enhanced soft X-ray emission surrounding an H I cloud imbedded in a cornal plasma, as suggested by Hayakawa et al. for the Lupus Loop