DESI

http://desi.lbl.gov/

图像巡天

• The Beijing-Arizona Sky Survey (BASS)
• The DECam Legacy Survey (DECaLS)
• The Mayall z-band Legacy Survey (MzLS)
• https://www.legacysurvey.org/

光谱巡天

• * 5000根光纤
• wavelength range 360 to 980 nm
• spectral resolution of R = between 2000 and 5500
• 天区覆盖：14000 deg2，总样本 30 million spectroscopic target
• 四个子样本

• (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)