2010/01/31 by Kenneth Rines, Margaret J. Geller, Antonaldo Diaferio
Physics and Astronomy · #Astronomy and Astrophysical Research #Cluster (spacecraft) #Galaxies: Formation, Evolution, Phenomena #Measure (data warehouse) #RADIUS #Range (aeronautics) #Redshift #Scaling #Stellar, planetary, and galactic studies #Virial coefficient #Virial mass #Virial theorem #astro-ph.CO
paper · pdf · doi:10.1088/2041-8205/715/2/l180
6 pages, 2 figures, accepted to ApJ Letters, minor revisions, shortened title
arxiv created 2010/05/04 · openalex publication_date 2010/05/14 · arxiv updated 2015/05/14 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present the first comparison of virial masses of galaxy clusters with their Sunyaev–Zel'dovich Effect (SZE) signals. We study 15 clusters from the Hectospec Cluster Survey (HeCS) with MMT/Hectospec spectroscopy and published SZE signals. We measure virial masses of these clusters from an average of 90 member redshifts inside the radius r 100 . The virial masses of the clusters are strongly correlated with their SZE signals (at the 99% confidence level using a Spearman rank-sum test). This correlation suggests that Y SZ can be used as a measure of virial mass. Simulations predict a power-law scaling of Y SZ ∝ M α 200 with α ≈ 1.6. Observationally, we find α = 1.11 ± 0.16, significantly shallower (given the formal uncertainty) than the theoretical prediction. However, the selection function of our sample is unknown and a bias against less massive clusters cannot be excluded (such a selection bias could artificially flatten the slope). Moreover, our sample indicates that the relation between velocity dispersion (or virial mass estimate) and SZE signal has significant intrinsic scatter, comparable to the range of our current sample. More detailed studies of scaling relations are therefore needed to derive a robust determination of the relation between cluster mass and SZE.