A very large array search for emission from H I associated with nearby Lyman α absorbers

We present a sensitive VLA search for H I emission from the vicinity of the Lyman α clouds in the Virgo Cluster, which were recently discovered with HST in absorption toward the nearest quasar 3C273. We searched an area of 40 by 40 arcmin centered on 3C273, covering a velocity range from 840 to 1840 km s^-1. The bandpass was self-calibrated on 3C273 leading to a spectral dynamic range of better than 10⁵ to 1. No H I was detected. The rms noise in the final images corresponds to a 3σ column density sensitivity of 2.8×10¹⁹ cm^-2 on scales of a few kpc. Small H I clouds could have been detected down to a few times 10⁶ script M sign _⊙. Our failure to detect H I in emission at the higher column densities sets a lower limit to the radius of the Lyman α clouds of 3.9 kpc, assuming a spherical geometry.