Da. Turnshek et al., The z=0.0912 and z=0.2212 damped Ly alpha galaxies along the sight line toward the quasar OI 363, ASTROPHYS J, 553(1), 2001, pp. 288-298
New optical and infrared observations along the sight line toward the quasa
r OI 363 (0738+313) are presented and discussed. Excluding quasars selectiv
ely observed because they were known to be located behind gas-rich galaxies
and systems which lack confirming UV spectroscopic observations of the act
ual Ly alpha Line, this sight line presently contains the two lowest redshi
ft classical damped Lya (DLA) quasar absorption-line systems found in surve
y mode (i.e., with N-H I >2 x 10(20) atoms cm(-2)), one at z(abs) = 0.0912
and the other at z(abs) = 0.2212. Our new observations suggest identficatio
ns for the DLA galaxy counterparts of these absorption-line systems. The z
= 0.09 DLA galaxy appears to be an extended low surface brightness galaxy w
hich is easily visible only in infrared images and shows possible rich morp
hological structure. Assuming there is no contribution from the quasar host
galaxy, we place an upper limit on the K-band luminosity of the z = 0.09 D
LA galaxy of L-K less than or equal to 0.13L*(K) (for a cosmology with H-0
= 65 km s(-1) Mpc(-1), Omega = 1, and Lambda = 0). More realistically, a su
btraction of the quasar nuclear and host light yields L(K)approximate to0.0
8L*(K). The impact parameter between the galaxy and quasar sight line is ve
ry small, b < 3.6 kpc(<2"), which makes measurements difficult. The z = 0.2
2 DLA galaxy is an early-type dwarf with a K-band luminosity of L(K)approxi
mate to0.1L*(K) at impact parameter b = 20 kpc. Its colors are neutral and
consistent with star formation models, suggesting its formation epoch was l
ess than a few Gyr ago (i.e., z(f) approximate to 0.3-0.9). Thus, it is con
ceivable that its progenitor originated from the population of "faint blue
galaxies" seen at moderate redshifts. In general, these results serve to su
pport mounting evidence that DLA galaxies are drawn from a wide variety of
gas-rich galaxy types.