No X-Ray-bright Type II Quasars among the Lyα Emitters

摘要: The Lyα emitters found at z = 4.5 and 5.7 by the Large Area Lyman Alpha (LALA) survey have high equivalent widths in line. Such lines can be produced narrow-lined active galactic nuclei or stellar populations with a very proportion of young massive stars. To check for type II (i.e., narrow-lined) quasars, we obtained deep X-ray image 49 sources single field ACIS instrument on Chandra X-Ray Observatory. None these was detected 3 σ limiting luminosity 2.9 × 1043 ergs s-1. For comparison, two known high-redshift quasars luminosities 4 s-1 before extinction correction. remain undetected stacked images (with 6.5 Ms effective on-axis exposure) limits 4.9 1042. resulting X-ray-to-Lyα ratio is about 4-24 times lower than while average LALA sample between II's. cumulative limit also below that 90% low-redshift Seyfert galaxies.