A1689
Determining cluster mass accurately is important for precision cosmology with clusters. As the X-ray hydrostatic equilibrium mass is subject to the bias from the bulk motion and turbulence in the intracluster medium (ICM), it is important to understand the X-ray mass - lensing mass comparison, as the latter measure also has its own systematics. In this proposal, we request XRISM data of one of the best studied cluster in lensing A1689 to study the line-of-sight (LoS) merger in its core, which is suggested from the previous studies and may hold the key to understand the X-ray mass - lensing mass discrepancy in the cluster. We will search for multiple LoS velocity components to constrain the ICM distribution along the LoS. The ICM turbulence in its weak cool core will also be constrained.
obsid = 202086010 / Unique Observation/Sequence Number
object = A1689 / Object name
pi_name = SUN MING / Proposal Principal Investigator Name
ra = 197.871673624828 / Right Ascension (Pointing Position) (deg)
dec = -1.3405460391163 / Declination (Pointing Position) (deg)
roll_angle = 115.001725581584 / Roll Angle (deg)
start_time = 2025-12-26T09:29:04 / Start Time of the Observation
stop_time = 2025-12-31T19:43:04 / Stop Time of the Observation
exposure = 227078.55406 / Effective Total Observation Exposure (s)
public_date= 2027-01-09 / Public Date