Discovery of Newly Formed Broad Absorption Lines in a Radio-Loud Quasar

We report a serendipitous discovery of broad absorption lines that were newly formed in the spectrum of the high-redshift, luminous radio-loud quasar TEX 1726+344, in a time interval of only 12 years. This is the first quasar showing a transition from narrow absorption lines to broad absorption lines. It also becomes one of the few radio-loud broad absorption line quasars. The gas cloud responsible for these broad absorption lines is derived to have parameters coinciding with those of the remnant of a tidally disrupted star. Subject headings: galaxies: active – quasars: absorption lines – quasar: emission lines – quasars: individual: TEX 1726+344