TY - JOUR
T1 - An Extreme-precision Radial-velocity Pipeline: First Radial Velocities from EXPRES
AU - Petersburg, Ryan R.
AU - Joel Ong, J. M.
AU - Zhao, Lily L.
AU - Blackman, Ryan T.
AU - Brewer, John M.
AU - Buchhave, Lars A.
AU - Cabot, Samuel H. C.
AU - Davis, Allen B.
AU - Jurgenson, Colby A.
AU - Leet, Christopher
AU - McCracken, Tyler M.
AU - Sawyer, David
AU - Sharov, Mikhail
AU - Tronsgaard, René
AU - Szymkowiak, Andrew E.
AU - Fischer, Debra A.
PY - 2020
Y1 - 2020
N2 - The EXtreme-PREcision Spectrograph (EXPRES) is an environmentally stabilized, fiber-fed, R = 137,500, optical spectrograph. It was recently commissioned at the 4.3 m Lowell Discovery Telescope near Flagstaff, Arizona. The spectrograph was designed with a target radial-velocity (RV) precision of 30 cm s−1. In addition to instrumental innovations, the EXPRES pipeline, presented here, is the first on-sky, optical, fiber-fed spectrograph to employ many novel techniques—including an “extended flat” fiber used for wavelength-dependent quantum efficiency characterization of the CCD, a flat-relative optimal extraction algorithm, chromatic barycentric corrections, chromatic calibration offsets, and an ultra-precise laser frequency comb for wavelength calibration. We describe the reduction, calibration, and RV analysis pipeline used for EXPRES and present an example of our current sub-meter-per-second RV measurement precision, which reaches a formal, single-measurement error of 0.3 m s−1 for an observation with a per-pixel signal-to-noise ratio of 250. These velocities yield an orbital solution on the known exoplanet host 51 Peg that matches literature values with a residual rms of 0.895 m s−1.
AB - The EXtreme-PREcision Spectrograph (EXPRES) is an environmentally stabilized, fiber-fed, R = 137,500, optical spectrograph. It was recently commissioned at the 4.3 m Lowell Discovery Telescope near Flagstaff, Arizona. The spectrograph was designed with a target radial-velocity (RV) precision of 30 cm s−1. In addition to instrumental innovations, the EXPRES pipeline, presented here, is the first on-sky, optical, fiber-fed spectrograph to employ many novel techniques—including an “extended flat” fiber used for wavelength-dependent quantum efficiency characterization of the CCD, a flat-relative optimal extraction algorithm, chromatic barycentric corrections, chromatic calibration offsets, and an ultra-precise laser frequency comb for wavelength calibration. We describe the reduction, calibration, and RV analysis pipeline used for EXPRES and present an example of our current sub-meter-per-second RV measurement precision, which reaches a formal, single-measurement error of 0.3 m s−1 for an observation with a per-pixel signal-to-noise ratio of 250. These velocities yield an orbital solution on the known exoplanet host 51 Peg that matches literature values with a residual rms of 0.895 m s−1.
U2 - 10.3847/1538-3881/ab7e31
DO - 10.3847/1538-3881/ab7e31
M3 - Journal article
SN - 0004-637X
VL - 159
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 5
M1 - 187
ER -