This is a brief summary of CSST based on CSST White Paper v1.2, which will introduce CSST major parameters, instruments, major topics, and so on.

• System Design
  • Major Optics System
  • Backend Modules
• Observational Ability
  • Multi-color photometry and slitless spectroscopy survey module
  • Multi-channel imaging system
  • Integral Field Spectrograph
  • Exo-planet imaging coronagraph
  • High-sensitivity THz module
• Scientific Targets
• Scientific research contents
  • Cosmology
  • Galaxies and AGN
  • Local Cosmology
  • Other Science

• Major Optics System

  • Optical Paths

  • Technical Indexs:

    • Clear aperture of major mirror (主镜通光口径): 2 m
    • Focal length (焦距): 28 m
    • Field of view (视场): >1.7 deg^2
    • Spatial resolution (R₈₀): ~0.13''
    • More details

• Backend Modules

  • 

  • Modules Introduction:

    1. Multi-color photometry and slitless spectroscopy survey module (多色成像和无缝光谱巡天模块)

       • Main focal plane: 60%(7bands, 18 filters): NUV, u, g, r, i, z, y
                  40%(3bands, 12 gratings): GU, GV, GI

       • 

       • Multi-color photoemtry system

         • Band information

         band	wavelength range (μm)	efficiency (>)	limiting magnitude	LM of ultra deep field
         NUV	0.255-0.32	0.26	25.4	26.7
         u	0.32-0.4	0.32	25.4	26.7
         g	0.4-0.55	0.58	26.3	27.5
         r	0.55-0.69	0.63	26.0	27.2
         i	0.69-0.82	0.62	25.9	27.0
         z	0.82-1.0	0.25	25.2	26.4
         y	0.93-1.0	0.25	24.4	25.7
         IR	0.9-1.7	0.25	24.4	25.7

       • Slitless spectroscopy system

         • Band information

         band	wavelength range (μm)	efficiency (>)	Resolution	LM	LM of ultra deep field
         GU	0.255-0.4	0.5	287	22	23
         GV	0.4-0.6	0.55	232	23	24
         GI	0.6-1.0	0.55	207	23	24

    2. Multi-channel imaging system (多通道成像仪)

    • three simultaneous channels
    • FOV: 7.5' × 7.5'
    • Band information

    band	wavelength range (μm)	LM
    CBU	0.255-0.43	29
    CBV	0.43-0.7	30
    CBI	0.7-1	29

    • 

    3. Integral Field Spectrograph (积分视场光谱仪)

       • Field of view (视场面积): 6 arcsec * 6 arcsec
       • Spatial resolution: 0.2 arcsec
       • Wavelength coverage: 0.35-1.0um
       • Spectroscopy resolution: R=1000 (0.35um)
       • Efficiency: 40%

    4. Exo-planet imaging coronagraph (系外行星成像星冕仪)

       • High image contrast: 10⁸
       • Field of view (视场面积): 10 arcsec * 10 arcsec
       • Spatial resolution: 0.13 arcsec
       • Wavelength coverage: 0.6-1.6um

    5. High-sensitivity THz module (高灵敏度太赫兹模块)

       • Parameters

       frequency range	bandwidth	resolution	sensitivity	beam width
       0.41-0.51 THz	2 GHz	100 kHz	150 mk	100''

1. Multi-color photometry and slitless spectroscopy survey module

   • Survey tasks overview

     • Early scientific observation (早期科学观测)：

       • 2 months for important proposals after successful orbit injection.

     • Deep multi-color imaging observation (深度多色成像观测)：

       • 15000 deg^2, focus on |b|>20 & |β|>20
       • more than 2 scans for each region
       • exposure time: 150s

     • Ultra deep multi-color imaging observation (极深度多色成像观测)：

       • 400 deg^2
       • 1 mag deeper
       • more than 8 scans for each region
       • exposure time: 250s

     • Slitless spectroscopy (无缝光谱观测)：

       • roughly same with deep multi-color imaging observation

     • Deep Slitless spectroscopy (无缝光谱观测)：

       • roughly same with ultra deep multi-color imaging observation

     • Follow-up (后续成像和光谱观测)：

       • 2500 deg^2, focus on 15<|b|<20
       • more than 2 scans for each region
       • exposure time: 150s

   • Simulation survey

     • 
       blue: 16,800 deg^2 deep field   red: 400 deg^2 ultra deep field
     • Coverage v.s. Time

2. Multi-channel imaging system

   • Major task

     • Photometry with high accuracy flux calibration
     • Ultra deep field in UV
     • Static universe & Time domain

   • Three modes

3. Integral Field Spectrograph

   • Focus on objects rather than regions:
     • 10h----20 objects
     • 2h----800 objects
   • Resolution: 1000
   • Surface luminosity v.s. Time
   • Simulation spectrum
     • Elliptical galaxy
     • Weak emission line galaxy
     • Strong emission line galaxy
     • Type I AGN

4. Exo-planet imaging coronagraph

   • PSF simulation

5. High-sensitivity THz module

   • Observing mode:

     • Position switching (位置切换)
     • On The Fly (OTF)

• Dark Energy, Dark Matter, and the Formation and Evolution of Cosmic Structure (暗能量、暗物质和宇宙结构形成和演化)

• the Origion and Evolution of Galaxy (星系起源与演化)

• AGN & the Formation and Evolution of SMBH (活动星系核和超大质量黑洞的形成和演化)

• Exoplanet, Astrometry, and Solar system (太阳系外行星、天体测量和太阳系天体)

1. Cosmology

   • 1.1. Dark Energy

     • BAO & RSD: 50,000,000 slitless spectrums of z<1.5 galaxies

     • Weak lensing

     • Strong lensing: FRB,SNs,Kilo Nova

   • 1.2 Dark Matter

     • Particle properties: Cold or warm? Axion? Self-interaction? Galaxy cluster.

     • Constrain of cosmology parameters

   • 1.3 Neutrino

     • Mass

   • 1.4 Gravity

     • Modified gravity

   • 1.5 Primordial pertubation

     • Power spectrum

2. Galaxies and AGN

   • 2.1. Morphology and structure of galaxies

     • Auto-classification of galaxy morpholoies

     • Decomposition and evolution of galaxy structures

     • Multi-band study of galaxies

     • Dwarf galaxies

     • Galaxy components: bar, spiral arm, stellar cluster...

     • Outside region of galaxies

   • 2.2 Evolution of galaxies and the dependence on environment

     • Complete sample and baisc statistic properties of low and middle redshift galaxies

     • Evolution of galaxies and stellar populations

     • Critical physical processes at cosmic noon

     • Strong emission line galaxies and special galaxies

     • Environment effects on galaxies on different scale

     • Galaxy group and galaxy cluster

     • Relationship within galactic gas, galaxy properties, and environment.

   • 2.3 High-redshift galaxy and cosmic reionization

     • High-redshift Lyman alpha emitter galaxies

     • High-redshift Lyman break galaxies

     • Cosmic reionization

     • High-redshift massive proto galaxy cluster

   • 2.4 AGN & SMBH

     • Quick construction of Large AGN and quasar sample

     • Statistic properties and cosmic evolution

     • Coevolution of galaxy and SMBH

     • Structure, physics, radiation mechanisms，and variability of AGN and quasar

     • Special AGN and quasar:

       • AGN merger
       • High-redshift quasars
       • SMBH in dwarf galaxies
       • Lensed quasars
       • Narrow Line Seyfert I Galaxies (NLSIs)

3. Local Cosmology

   • 3.1 The fine structure, formation, and evolution of the Milky Way.

     • Stellar basic information: Effective temperature, metallicity, log g......

     • Find extremely metal-poor stars

     • Study the frontier of the Milky Way

     • Large white dwarf sample

   • 3.2 The Multiple Populations and Dynamic Evolution of Stellar Clusters.

   • 3.3 Structure and Dark Matter Distribution of Local Galaxies

     • Finding satellites, dwarf galaxies of local galaxies (e.g. M31)

     • Matter distribution of satellites

     • Formation history of satellites

     • Proper motion catelogue of local objects

     • Age-metallicity relation

   • 3.4 Extinction Law of Milky Way and Local Galaxies

4. Other Science

   • 4.1 Solar System

     • Kuiper Belt Objects, KBOs

     • Study of small celestial objects with large orbit inclination in outer solor system (外太阳系高轨道倾角小天体研究)

   • 4.2 Celestial objects and comets

   • 4.3 Transient Sources and Variable Sources

     • Optical counterpart of gravitational source

     • Transient accretion event of SMBH: TDE, Changing-look quasar