Palmese, A., Annis, J., Burgad, J., Farahi, A., Soares-Santos, M., Welch, B., da Silva Pereira, M., Lin, H., Bhargava, S., Hollowood, D. L., Wilkinson, R., Giles, P., Jeltema, T., Romer, A. K., Evrard, A. E., Hilton, M., Vergara Cervantes, C., Bermeo, A., Mayers, J., DeRose, J., Gruen, D., Hartley, W. G., Lahav, O., Leistedt, B., McClintock, T., et al
Abstract
We introduce a galaxy cluster mass observable, µ?, based on the stellar masses of cluster members, and we present results for the Dark Energy Survey (DES) Year 1 (Y1) observations. Stellar masses are computed using a Bayesian model averaging method, and are validated for DES data using simulations and COSMOS data. We show that µ? works as a promising mass proxy by comparing our predictions to X-ray measurements. We measure the X-ray temperature-µ? relation for a total of 129 clusters matched between the wide-field DES Y1 redMaPPer catalogue and Chandra and XMM archival observations, spanning the redshift range 0.1 relation for a total of 129 clusters matched between the wide-field DES Y1 redMaPPer catalogue and Chandra and XMM archival observations, spanning the redshift range 0.1 relation for a total of 129 clusters matched between the wide-field DES Y1 redMaPPer catalogue and Chandra and XMM archival observations, spanning the redshift range 0.1 ? of s _{ln T_ X|µ _\star }= 0.266^{+0.019}_{-0.020} for the joint sample. By using the halo mass scaling relations of the X-ray temperature from the Weighing the Giants program, we further derive the µ?-conditioned scatter in mass, finding s _{ln M|µ _\star }= 0.26^{+ 0.15}_{- 0.10}. These results are competitive with well-established cluster mass proxies used for cosmological analyses, showing that µ? can be used as a reliable and physically motivated mass proxy to derive cosmological constraints.
