EVIDENCE OF AN IONIZED IRON EMISSION-LINE FROM THE RADIO-QUIET QUASARE1821+643 BY ASCA

We present the results of an ASCA observation of the radio-quiet quasa r E1821 + 643. The 2-10 keV flux and the power-law index are consisten t with the values reported previously by EXOSAT, Ginga, and BBXRT. The iron K-emission line feature discovered by the Ginga observations is confirmed, and its redshift-corrected, line-center energy is better de termined to be 6.58 +/- 0.05 keV. This line feature shows marginal bro adening with an upper limit of 180 eV in Gaussian sigma (in the quasar rest frame). The line equivalent width is 170 +/- 50 eV in the quasar rest frame, which is consistent with the Ginga measurement, and the c ontribution from the quasar-associated cluster of galaxies is estimate d to be negligible.