Abstract
The Chinese Space Station Telescope (CSST) spectroscopic survey plans to deliver high-quality low-resolution (R > 200) slitless spectra for hundreds of millions of targets down to a limiting magnitude of about 21 mag, covering a large survey area (17 500 deg2) and a wide wavelength range (255–1000 nm by three bands GU, GV, and GI). In this work, we use empirical spectra of the Next Generation Spectral Library to simulate the CSST stellar spectra at R = 250, and investigate their capabilities in measuring radial velocities. We find that velocity uncertainties depend strongly on effective temperature, weakly on metallicity for only FGK stars, and hardly on surface gravity. It is possible to deliver stellar radial velocities to a precision of about 3 km s−1 for AFGKM stars, and about 10 km s−1 for OB stars, at signal-to-noise ratio (SNR) of 100. Velocity uncertainties using single GU/GV/GI band spectra are also explored. Given the same SNR, the GU band performs best, the GV band the second best, and then the GI band. The effects of spectral normalization and the imperfect template on velocity measurements are investigated and found to be very weak. The uncertainties caused by wavelength calibration are considered and found to be moderate. Given the possible precision of radial velocities, the CSST spectroscopic survey can enable interesting science such as searching for hyper-velocity stars. Limitations of our results are also discussed.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.