Evidence for rotation in the galaxy at z=3.15 responsible for a damped Lyman-alpha absorption system in the spectrum of Q2233+1310

被引:26
作者
Lu, LM
Sargent, WLW
Barlow, TA
机构
[1] California Institute of Technology, 105-24, Pasadena
关键词
galaxies; distances and redshifts; kinematics and dynamics; quasars; absorption lines; individual; (Q2233+1310);
D O I
10.1086/304326
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Proof of the existence of a significant population of normal disk galaxies at redshift z > 2 would have profound implications for theories of structure formation and evolution. We present evidence based on Keck HIRES spectra that the damped Ly alpha absorber at z = 3.15 toward the quasar Q2233 + 1310 may well be such an example. Djorgovski et al. have recently detected the Ly alpha emission from the absorber, which we assume is at the systemic redshift of the absorbing galaxy. By examining the profiles of the metal absorption lines arising from the absorbing galaxy in relation to its systemic redshift, we find strong kinematical evidence for rotation. Therefore the absorber is likely to be a disk galaxy. The inferred circular velocity for the galaxy is greater than or equal to 200 km s(-1). With a separation of similar or equal to 17 kpc (q(0) = 0.1, H-0 = 75) between the galaxy and the quasar sight line, the implied dynamic mass for the galaxy is greater than or equal to 1.6 x 10(11) M.. The metallicity of the galaxy is found to be [Fe/H] = -1.4, typical of damped Ly alpha galaxies at such redshifts. However, in another damped Ly alpha absorber at z = 2.81 toward Q0528-2505, no kinematical evidence for galactic rotation is evident. In the latter case, the damped Ly alpha absorber occurs near the background quasar in redshift, so its properties may be influenced by the background quasar. These represent the only two cases at present for which the technique used here may be applied. Future applications of the same technique to a large sample of damped Ly alpha galaxies may allow us to determine if a significant population of disk galaxies already existed only a few billion years after the big bang.
引用
收藏
页码:131 / 134
页数:4
相关论文
共 17 条
[1]   Identification of a galaxy responsible for a high-redshift Lyman-alpha absorption system [J].
Djorgovski, SG ;
Pahre, MA ;
Bechtold, J ;
Elston, R .
NATURE, 1996, 382 (6588) :234-236
[2]  
Grosbol P. J., 1985, Astronomy & Astrophysics Supplement Series, V60, P261
[3]   CCD SURFACE PHOTOMETRY OF FIELD GALAXIES .2. BULGE DISK DECOMPOSITIONS [J].
KENT, SM .
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 1985, 59 (02) :115-159
[4]   THE KINEMATICS OF INTERMEDIATE-REDSHIFT GASEOUS GALAXY HALOS [J].
LANZETTA, KM ;
BOWEN, DV .
ASTROPHYSICAL JOURNAL, 1992, 391 (01) :48-72
[5]  
LU L, 1997, UNPUB
[6]   A SPECTROSCOPIC STUDY OF DAMPED LYMAN-ALPHA SYSTEMS IN THE LAS CAMPANAS PALOMAR SURVEY [J].
LU, LM ;
WOLFE, AM ;
TURNSHEK, DA ;
LANZETTA, KM .
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 1993, 84 (01) :1-38
[7]   Abundances at high redshifts: The chemical enrichment history of damped Ly alpha galaxies [J].
Lu, LM ;
Sargent, WLW ;
Barlow, TA ;
Churchill, CW ;
Vogt, SS .
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 1996, 107 (02) :475-519
[8]   METAL ENRICHMENT, DUST, AND STAR-FORMATION IN GALAXIES AT HIGH REDSHIFTS .3. ZN AND CR ABUNDANCES FOR 17 DAMPED LYMAN-ALPHA SYSTEMS [J].
PETTINI, M ;
SMITH, LJ ;
HUNSTEAD, RW ;
KING, DL .
ASTROPHYSICAL JOURNAL, 1994, 426 (01) :79-96
[9]   A Keck hires investigation of the metal abundances and kinematics of the z=2.46 damped Ly alpha system toward Q0201+365 [J].
Prochaska, JX ;
Wolfe, AM .
ASTROPHYSICAL JOURNAL, 1996, 470 (01) :403-443
[10]  
PROCHASKA JX, 1997, IN PRESS APJ