H1821+643
We propose a 250 ks XRISM observation of H1821+643, a recoiling and extremely accreting supermassive black hole (SMBH) in a cooling flow cluster. Cooling flows are expected to have a huge impact on the active galactic nuclei (AGNs), yet they are scarcely observed in the local Universe, known as the cooling flow problem. H1821+643 is an irreplaceable target hosting cooling flows and a radio-quiet quasar. We will measure the turbulent motions within the cooling core to understand quasar-mode feedback. To comprehend how the SMBH acquires its large mass, we will also examine the AGN structure (torus, broad-line region, and accretion disk) by resolving the complex Fe lines. This observation will reveal new frontiers on the long-standing cooling flow problem and SMBH formation in cooling cores.
obsid = 201030010 / Unique Observation/Sequence Number
object = H1821+643 / Object name
pi_name = YAMADA SATOSHI / Proposal Principal Investigator Name
ra = 275.488927472562 / Right Ascension (Pointing Position) (deg)
dec = 64.3438611688527 / Declination (Pointing Position) (deg)
roll_angle = 289.999644029951 / Roll Angle (deg)
start_time = 2024-09-04T02:25:04 / Start Time of the Observation
stop_time = 2024-09-10T01:35:04 / Stop Time of the Observation
exposure = 283716.43058 / Effective Total Observation Exposure (s)
public_date= 2025-09-19 / Public Date