Abstract
The kinematic and thermal Sunyaev-Zel'dovich (kSZ and tSZ) effects probe the
abundance and thermodynamics of ionized gas in galaxies and clusters. We
present a new hybrid estimator to measure the kSZ effect by combining cosmic
microwave background temperature anisotropy maps with photometric and
spectroscopic optical survey data. The method interpolates a velocity
reconstruction from a spectroscopic catalog at the positions of objects in a
photometric catalog, which makes it possible to leverage the high number
density of the photometric catalog and the precision of the spectroscopic
survey. Combining this hybrid kSZ estimator with a measurement of the tSZ
effect simultaneously constrains the density and temperature of free electrons
in the photometrically selected galaxies. Using the 1000 deg2 of overlap
between the Atacama Cosmology Telescope (ACT) Data Release 5, the first three
years of data from the Dark Energy Survey (DES), and the Baryon Oscillation
Spectroscopic Survey (BOSS) Data Release 12, we detect the kSZ signal at
4.8$\sigma$ and reject the null (no-kSZ) hypothesis at 5.1$\sigma$. This
corresponds to 2.0$\sigma$ per 100,000 photometric objects with a velocity
field based on a spectroscopic survey with 1/5th the density of the photometric
catalog. For comparison, a recent ACT analysis using exclusively spectroscopic
data from BOSS measured the kSZ signal at 2.1$\sigma$ per 100,000 objects.
Our derived constraints on the thermodynamic properties of the galaxy halos are
consistent with previous measurements. With future surveys, such as the Dark
Energy Spectroscopic Instrument and the Rubin Observatory Legacy Survey of
Space and Time, we expect that this hybrid estimator could result in
measurements with significantly better signal-to-noise than those that rely on
spectroscopic data alone.
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