ASCA observations of RX J1838.4-0301

The results of ASCA observations of RX J1838.4-0301 are presented. The sour ce was found to be faint and there was no obvious X-ray flare during the AS CA observation. No evidence for pulsations was found near to the 5.45 s per iod previously reported from ROSAT observations. The source energy spectrum cannot be fitted well with either a single-component power law, thermal br emsstrahlung, or blackbody emission model, while a variety of two component models do give acceptable fits. The flux which we derive is consistent wit h that measured in the quiescent state with ROSAT. On the basis of the ROSA T and ASCA results, we suggest that RX J1838.4-0301 may be a transient sour ce in which the quiescent state has a fairly constant flux level. However, our results do not yet enable a clear determination of whether this source is an anomalous X-ray pulsar or some other type of object.