Large Area Multi-Object Spectroscopic Telescope Research Articles

Forecasting the dark energy measurement with baryon acoustic oscillations: prospects for the LAMOST surveys

The Large Area Multi-Object Spectroscopic Telescope (LAMOST) is a dedicated spectroscopic survey telescope being built in China, with an effective aperture of 4 meters and equiped with 4000 fibers. Using the LAMOST telescope, one could make redshift survey of the large scale structure (LSS). The baryon acoustic oscillation (BAO) features in the LSS power spectrum provide standard rulers for measuring dark energy and other cosmological parameters. In this paper we investigate the meaurement precision achievable for a few possible surveys: (1) a magnitude limited survey of all galaxies, (2) a survey of color selected red luminous galaxies (LRG), and (3) a magnitude limited, high density survey of z<2 quasars. For each survey, we use the halo model to estimate the bias of the sample, and calculate the effective volume. We then use the Fisher matrix method to forecast the error on the dark energy equation of state and other cosmological parameters for different survey parameters. In a few cases we also use the Markov Chain Monte Carlo (MCMC) method to make the same forecast as a comparison. The fiber time required for each of these surveys is also estimated. These results would be useful in designing the surveys for LAMOST.

A new configuration for a 10-metre optical/infrared telescope

A new configuration for a 10 m optical/infrared telescope for high-resolution work is proposed. While similar in some respects to the Hobby Eberly 9 m telescope (HET) and the Large Area Multi-Object Spectroscopic Telescope (LAMOST), its characteristics are: a spherical segmented primary made of 91 hexagonal sub-mirrors of size 1.2 m each, (with real-time co-focus, and, for infrared observation only, co-phase), a focal ratio of 1.7, giving a field of 6–8 arc min, a meridian-instrument type of mounting, covering 100° in declination, the primary being fixed during observation, the tracking being done by a 4-component corrector housed in a frame that moves along guides, themselves fixed to the ground. It is a low-cost (about 13–20 million US dollars), low risk configuration, and it can be expected to be also suitable for much larger telescopes of apertures several tens of metres.