COMPARISON OF HECTOSPEC VIRIAL MASSES WITH SUNYAEV-ZEL'DOVICH EFFECT MEASUREMENTS
- Department of Physics and Astronomy, Western Washington University, Bellingham, WA 98225 (United States)
- Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States)
- Dipartimento di Fisica Generale 'Amedeo Avogadro', Universita degli Studi di Torino, Torino (Italy)
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 {sub 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 {sub SZ} can be used as a measure of virial mass. Simulations predict a power-law scaling of Y {sub SZ} {proportional_to} M {sup {alpha}} {sub 200} with {alpha} {approx} 1.6. Observationally, we find {alpha} = 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.
- OSTI ID:
- 21448687
- Journal Information:
- Astrophysical Journal Letters, Vol. 715, Issue 2; Other Information: DOI: 10.1088/2041-8205/715/2/L180; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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