A damped Lyα candidate at z~0.1 towards Q0439-433.

Abstract

We report on the detection of a Z_gal_=0.101 galaxy projected on the sky at 4.2arcsec (or 5.2h^-1^_100_kpc for q_0_=0.5) from the quasar Q 0439-433 (z_em_=0.594). The HST spectrum of the quasar shows strong Mg II, Fe II, Si II, Al II and C IV absorption lines at the same redshift as the galaxy. The equivalent width ratios of the low ionization lines indicate that this system is probably damped with a neutral hydrogen column density of N(HI)~10^20^cm-2. The C IV doublet presents a complex structure and in particular a satellite with a velocity v=1100km/s relative to the galaxy. Additional HST and redshifted 21cm observations of this QSO-galaxy pair would offer an ideal opportunity to study the morphology of a damped absorber and the kinematics of the halo of a low-redshift galaxy.