DESI

http://desi.lbl.gov/

• previously BigBOSS

图像

• BASS[1] lead by Zhouxu
• DECaLS

光谱巡天

• 5 000 spectra simultaneously
• wavelength range 360 to 980 nm *
• spectral resolution of R = between 2000 and 5 500,
• fi�ve-year survey starting in 2020,
• measuring redshifts over a solid angle of 14 000 deg2
• More than 30 million spectroscopic targets will be selected for four different tracer samples

• (i) luminous red galaxies (LRGs) in the redshift range z = 0.3 to z = 1
• (ii) emission line galaxies (ELGs) to z = 1.7
• (iii) quasars to higher redshifts (2.1 < z < 3.5)
• (iv) a magnitude-limited Bright Galaxy Survey out to z~0.6 with a median redshift of z~0.2

BGS

• 在bright observing time进行
• a flux limited sample of around 10 million galaxies
• r<19.5 (800 galaxies/deg^2)
• 19.5 < r < 20 (a secondary sample, 600 galaxies/deg^2)