Line confusion in spectroscopic surveys and its possible effects: Shifts in Baryon Acoustic Oscillations position

Abstract

Roman Space Telescope will survey about 17 million emission-line galaxies over a range of redshifts. Its main targets are H$\alpha$ emission-line galaxies at low redshifts and [O III] emission-line galaxies at high redshifts. The Roman Space Telescope will estimate the redshift these galaxies with single line identification. This suggests that other emission-line galaxies may be misidentified as the main targets. In particular, it is hard to distinguish between the H$\beta$ and [O III] lines as the two lines are close in wavelength and hence the photometric information may not be sufficient to separate them reliably. Misidentifying H$\beta$ emitter as [O III] emitter will cause a shift in the inferred radial position of the galaxy by approximately 90 Mpc/h. This length scale is similar to the Baryon Acoustic Oscillation (BAO) scale and could shift and broaden the BAO peak, possibly introduce errors in determining the BAO peak position. We qualitatively describe the effect of this new systematic and further quantify it with a lightcone simulation with emission-line galaxies.

References in corpus (5)

• K-corrections and filter transformations in the ultraviolet, optical, and near infrared
• Wide-Field InfrarRed Survey Telescope-Astrophysics Focused Telescope Assets WFIRST-AFTA 2015 Report
• The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: measurement of the BAO and growth rate of structure of the luminous red galaxy sample from the anisotropic correlation function between redshifts 0.6 and 1
• The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: measurement of the BAO and growth rate of structure of the luminous red galaxy sample from the anisotropic power spectrum between redshifts 0.6 and 1.0
• The Wide Field Infrared Survey Telescope: 100 Hubbles for the 2020s

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• Correcting correlation functions for redshift-dependent interloper contamination
• The Effect of Systematic Redshift Biases in BAO Cosmology
• Precise self-calibration of interloper bias in spectroscopic surveys
• Self-calibrating BAO measurements in the presence of Small Displacement Interlopers
• Diagnosing Systematic Effects Using the Inferred Initial Power Spectrum