TY - JOUR
T1 - A new H I 21 centimeter absorber associated with the H I deficient interacting galaxies G0248+430
AU - Hwang, Chorng Yuan
AU - Chiou, Shwu Huey
PY - 2004/1/1
Y1 - 2004/1/1
N2 - We present high-resolution (∼2″) H I 21 cm and CO(1-0) observations of the quasar (QSO) galaxy pair 0248+430. The QSO Q0248+430 (z em = 1.313) has been found to show two metal absorption-line systems at redshifts za ∼ 0.052, which are consistent with the redshift of a foreground luminous infrared galaxy 15″ (∼11 h-1 kpc) away. In our observations, the CO emission of this foreground galaxy, G0248+430, shows broad velocity distribution (∼173 km s-1) but is spatially confined to a small unresolved region less than 1.5 × 1.5 h -1 kpc; the H2 mass based on the traditional conversion factor is ≈1010 M⊙, which is approximately 30 times the H2 mass within a similar region of the Milky Way. On the other hand, no significant H I 21 cm emission is found in the foreground galaxy; the mass of the neutral atomic hydrogen is less than 6 × 10 8 M⊙. Toward the QSO we discover a new H I 21 cm absorber with τdv ∼ 0.26 km s-1 at the redshift of one of the metal absorption components; however, we did not detect significant CO(1-0) absorption toward the QSO. The H I column density is large enough for the absorber to be classified as a damped Lyα system. We also derive the H I mass and spin temperature for this metal-line absorption system. We discuss the relation of this H I absorber and the depletion of the H I in the foreground galaxy. We find that this H I absorber has very high metal abundance and is intrinsically different from the normal damped Lyα- absorption systems, although both have similar spin temperatures and hydrogen column densities.
AB - We present high-resolution (∼2″) H I 21 cm and CO(1-0) observations of the quasar (QSO) galaxy pair 0248+430. The QSO Q0248+430 (z em = 1.313) has been found to show two metal absorption-line systems at redshifts za ∼ 0.052, which are consistent with the redshift of a foreground luminous infrared galaxy 15″ (∼11 h-1 kpc) away. In our observations, the CO emission of this foreground galaxy, G0248+430, shows broad velocity distribution (∼173 km s-1) but is spatially confined to a small unresolved region less than 1.5 × 1.5 h -1 kpc; the H2 mass based on the traditional conversion factor is ≈1010 M⊙, which is approximately 30 times the H2 mass within a similar region of the Milky Way. On the other hand, no significant H I 21 cm emission is found in the foreground galaxy; the mass of the neutral atomic hydrogen is less than 6 × 10 8 M⊙. Toward the QSO we discover a new H I 21 cm absorber with τdv ∼ 0.26 km s-1 at the redshift of one of the metal absorption components; however, we did not detect significant CO(1-0) absorption toward the QSO. The H I column density is large enough for the absorber to be classified as a damped Lyα system. We also derive the H I mass and spin temperature for this metal-line absorption system. We discuss the relation of this H I absorber and the depletion of the H I in the foreground galaxy. We find that this H I absorber has very high metal abundance and is intrinsically different from the normal damped Lyα- absorption systems, although both have similar spin temperatures and hydrogen column densities.
KW - Galaxies: interactions
KW - Galaxies: starburst
KW - Quasars: absorption lines
KW - Radio lines: galaxies
UR - http://www.scopus.com/inward/record.url?scp=1642285995&partnerID=8YFLogxK
U2 - 10.1086/379786
DO - 10.1086/379786
M3 - 期刊論文
AN - SCOPUS:1642285995
SN - 0004-637X
VL - 600
SP - 52
EP - 58
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1 I
ER -