Damped Ly alpha absorption associated with an early-type galaxy at redshift z=0.16377

Lanzetta, KM
Wolfe, AM
Altan, Hakan
Barcons, X
Chen, HW
FernandezSoto, A
Meyer, DM
OrtizGil, A
Savaglio, S
Webb, JK
Yahata, N
We report new HST and ground-based observations of a damped Ly alpha absorption system toward the QSO 0850+4400. The redshift of the absorption system is z = 0.163770+/-0.000054 and the neutral hydrogen column density of the absorption system is log N = 19.81+/-0.04 cm(-2). The absorption system is by far the lowest redshift confirmed damped Ly alpha absorption system yet identified, which provides an unprecedented opportunity to examine the nature, impact geometry, and kinematics of the absorbing galaxy in great detail. The observations indicate that the absorption system is remarkable in three respects: First. the absorption system is characterized by weak metal absorption lines and a low metal abundance, possibly less than 4% of the solar metal abundance. This cannot be explained as a consequence of obscuration by dust, because the neutral hydrogen column density of the absorption system is far too low for obscuration by dust to introduce any significant selection effects. Second, the absorption system is associated with a moderate-luminosity early-type S0 galaxy, although the absorption may actually arise in one of several very faint galaxies detected very close to the QSO line of sight. Third, the absorbing material moves counter to the rotating galaxy disk, which rules out the possibility that the absorption arises in a thin or thick co-rotating gaseous disk. These results run contrary to the expectation that low-redshift damped Ly alpha absorption systems generally arise in the gas-and metal-rich inner parts of late-type spiral galaxies. We suggest instead that mounting evidence indicates that low-redshift galaxies of a variety of morphological types may contain significant quantities of low metal abundance pas at large galactocentric distances. (C) 1997 American Astronomical Society.


Modulation of alpha oscillations is required for the suppression of semantic interference
Melnik, Natalia; Mapelli, Igor; Özkurt, Tolga Esat (2017-10-01)
Recent findings on alpha band oscillations suggest their important role in memory consolidation and suppression of external distractors such as environmental noise. However, less attention was given to the phenomenon of internal distracting information being solely inherent to the stimuli content. Human memory may be prone to internal distractions caused by semantic relatedness between the meaning of words (e.g., atom, neutron, nucleus, etc.) to be encoded, i.e., semantic interference. Our study investigate...
Temperature-dependent radiative lifetimes of excitons in non-polar GaN/AlGaN quantum wells
Rudin, S.; Garrett, G. A.; Shen, H.; Wraback, M.; İmer, Muhsine Bilge; Haskell, B.; Speck, J. S.; Keller, S.; Nakamura, S.; DenBaars, S. P. (2007-01-01)
We report theoretical and experimental studies of radiative recombination of carriers in GaN quantum wells grown on low defect a-plane GaN templates fabricated by lateral epitaxial overgrowth. The radiative rates are presented as functions of temperature and well width.
Isovector response of nuclear matter at finite temperature
Ayik, S.; BOZKURT, Kutsal; Gokalp, A.; Yılmaz Tüzün, Özgül (2008-06-01)
The dipole response function of nuclear matter at zero and finite temperatures is investigated in an extended RPA approach by including collisional damping mechanism and coherent damping due to particle-phonon coupling. Calculations are carried out for nuclear dipole vibrations by employing the Steinwedel-Jensen model and compared with experimental results for Sn-120 and Pb-208.
UKF based in-flight calibration of magnetometers and rate gyros for pico satellite attitude determination
Söken, Halil Ersin (Wiley, 2012-05-01)
In this paper an unscented Kalman filter based procedure for the bias estimation of both the magnetometers and the gyros carried onboard a pico satellite, is proposed. At the initial phase, biases of three orthogonally located magnetometers are estimated as well as the attitude and attitude rates of the satellite. During the initial period after the orbit injection, gyro measurements are accepted as bias free since the precise gyros are working accurately and the accumulated gyro biases are negligible. At t...
Yurtseven, Hasan Hamit (World Scientific Pub Co Pte Lt, 2010-12-20)
We study here the Raman frequencies of the lattice modes (gamma and beta phases) and of an internal mode (gamma phase) as a function of temperature in solid nitrogen. The frequency shift, derived from the anharmonic self energy, is fitted to the experimental data for the Raman frequencies of the modes considered here in the gamma and beta phases of solid nitrogen.
Citation Formats
K. Lanzetta et al., “Damped Ly alpha absorption associated with an early-type galaxy at redshift z=0.16377,” ASTRONOMICAL JOURNAL, pp. 1337–1344, 1997, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/33309.