Millimeter/Submillimeter Search for the Sunyaev‐Zeldovich Effect in the Coma Cluster

Abstract

Observations from the first flight of the Medium Scale Anisotropy Measurement (MSAM1-92) are analyzed to search for the Sunyaev-Zel'dovich (SZ) effect towards the Coma cluster. This balloon-borne instrument uses a 28 ′ FWHM beam and a three position chopping pattern with a throw of ±40 ′ . With spectral channels at 5.7, 9.3, 16.5, and 22.6 cm −1 , the observations simultaneously sample the frequency range where the SZ spectral distortion in the intensity transitions from a decrement to an increment and where the fractional intensity change is substantially larger than in the Rayleigh-Jeans region. We set limits on the Comptonization parameter integrated over our antenna pattern, ∆y ≤ 8.0 × 10 −5 (2σ). For a spherically symmetric isothermal model, this implies a central Comptonization parameter, y o ≤ 2.0 × 10 −4 , or a central electron density, n o ≤ 5.8 × 10 −3 cm −3 h 50 , a result consistent with central densities implied by X-ray brightness measurements and central Comptonization estimates from lower frequency observations of the SZ effect.

MITO Measurements of the Sunyaev-Zeldovich Effect in the Coma Cluster of Galaxies

“…Attempts to measure the SZ effect in Coma at low frequencies were reported by Pariskij (1973), Rudnick (1978), Lake & Partridge (1980), Birkinshaw, Gull, & Northover (1981), and Herbig, Lawrence, & Readhead (1995;revised in Mason, Myers, & Readhead 2001) and at high frequencies by Silverberg et al (1997).…”

Planckintermediate results

“…Its intracluster medium (ICM) was observed in SZ for the first time with the 5.5 m OVRO telescope (Herbig et al 1992(Herbig et al , 1995. Later, it was also observed with MSAM1 (Silverberg et al 1997), MITO (De Petris et al 2002), VSA (Lancaster et al 2005) and WMAP (Komatsu et al 2011) which detected the cluster with signal-to-noise ratio of S /N = 3.6. As reported in the all-sky early Sunyaev-Zeldovich cluster paper, Planck detected the Coma cluster with a S /N > 22 (Planck Collaboration 2011d).…”

The Cosmic Microwave Background

“…Observations of the SZ effect have been made in Cambridge using the Ryle telescope, which is an 8-dish interferometer operating at 15 GHz [80], in Caltech using the Owen's Valley 5.5m telescope [61], the Owen's Valley 40m telescope [41] and the Owen's Valley Millimeter Array (OVMMI) [14] [15], at NASA using the MSAM balloon experiment [84], at the Caltech Submillimeter Observatory using a purpose built instrument called the Sunyaev-Zel'dovich Infrared Experiment (SuZIE) [39] and by various other groups. The magnitude of the observed SZ effect in these clusters can be combined with X-ray data from ROSAT and ASCA to place limits on H 0 .…”