NOAO >   Observing Info >   Approved Programs >   2005A-0138

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Proposal Information for 2005A-0138


PI: Kimiaki Kawara, University of Tokyo, kkawara@ioa.s.u-tokyo.ac.jp
Address: Institute of Astronomy, 2-21-2 Osawa, Mitaka, Tokyo 181-0015, Japan

CoI: Yoshiki Matsuoka, University of Tokyo
CoI: Yumihiko Tsuzuki, University of Tokyo
CoI: Shinki Oyabu, University of Tokyo
CoI: Yuzuru Yoshii, University of Tokyo

Title: OI lines as the indicator of microturbulence in quasar broad-line region

Abstract: We propose to do near-infrared spectroscopy to investigate the OI(lambda)1304 line forming process in a BLR(Broad-Line Region) gas of quasars. The FeII/MgII emission line ratio in high-z quasar is recognized as a potential cosmological clock. However nowadays, various models have been suggesting that several physical properties of quasars including gas densities would control the FeII/MgII flux ratio as well as the Fe/Mg abundance does. As far as a BLR gas is concerned, no methods have been established to estimate the effect of the microturbulence on the FeII/MgII ratio, while the effects of the other non-abundance factors can be measured to a certain extent by using the ratios of various emission lines other than FeII and MgII. As a potential indicator of the microturbulence, we are now expecting the OI(lambda)1304 line strength. The dominant mechanism of the formation of this line is considered to be the Ly(beta) pumping, because the velocity shift by the microturbulence would make the Ly(beta) pumping efficient. We wish to test our idea that the Ly(beta) pumping is really the dominant process of the OI(lambda)1304 formation, using the three OI(lambda)1304, 8446 and 11287 lines. In case of the pure Ly(beta) pumping, a photon ratio of 1:1:1 is expected for these lines.


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