Oral Presentation

HectoMAP Galaxy Cluster Surveys

Author(s): Jubee Sohn (Harvard-Smithsonian Center for Astrophysics)

Presenter: Jubee Sohn (Havard-Smithsonian Center for Astrophysics)

HectoMAP is a dense redshift survey covering a 53 square-degree field of the sky. The Hyper Suprime Cam (HSC) Subaru Strategic Program (SSP) covers the HectoMAP field. As such, HectoMAP is an important testbed for galaxy cluster surveys based on deep photometry and dense spectroscopy. We first test the redMaPPer catalog; we evaluate the redMaPPer membership probability spectroscopically and identify spectroscopic members of 104 redMaPPer cluster candidates. More than 90% of HectoMAP redMaPPer clusters have at least 10 spectroscopic members even at low richness. We also construct an X-ray cluster catalog using ROSAT All-Sky Survey (RASS) data. We find 15 clusters (7 newly discovered) with a redshift z ≤ 0.4 to the X-ray flux limit of the RASS (∼ 3 × 10−13 erg s−1 cm−2). Three X-ray clusters covered with the HSC images are impressive. One of them shows strong lensing arcs. We predict that there are ∼ 12000 ± 3000 detectable X-ray clusters in the RASS, comparable to the estimate based on the XXL cluster survey (Pacaud et al. 2016). The combination of HectoMAP and future multi-wavelength surveys including complete HSC imaging, a Prime Focus Spectrograph survey, and an e-ROSITA survey will provide a robust catalog of clusters for increasingly sophisticated tests of cluster evolution and for the determination of cosmological parameters.