Arcus (satellite)

Arcus is a planned NASA astrophysics mission designed to study the hot, diffuse plasma that pervades galaxy clusters and the circumgalactic medium (CGM) of galaxies. It will achieve this by employing high-resolution X-ray spectroscopy, enabling the measurement of the temperatures, densities, and velocities of these plasmas with unprecedented precision. This will allow scientists to investigate fundamental questions about galaxy formation and evolution, the role of feedback processes from active galactic nuclei (AGN), and the distribution of dark matter.

Key Scientific Goals:

• Understanding the physics of galaxy cluster and CGM plasmas: Arcus will measure the temperature, density, and velocity structure of these plasmas with high resolution, revealing crucial details about their physical properties and dynamics.
• Tracing the flow of gas in and out of galaxies: By studying the distribution and motion of gas, Arcus will shed light on how galaxies acquire and lose material throughout their lifetimes.
• Investigating the role of AGN feedback: Arcus will study the impact of AGN outflows on the surrounding gas, helping to understand how these powerful engines regulate star formation and galaxy growth.
• Searching for dark matter signatures: The exquisite sensitivity of Arcus may allow detection of subtle signatures related to dark matter interactions.

Instrumentation:

The mission will utilize a suite of microcalorimeter detectors offering high spectral resolution at energies from 0.3 to 10 keV. This will allow the detection of faint emission lines crucial for detailed plasma diagnostics.

Mission Timeline:

While the mission concept has been extensively studied, including phases of technology development and pre-project studies, it has not yet been selected for flight by NASA. The timeline for launch (if selected) remains uncertain.

Related Missions:

Arcus's scientific goals are complementary to those of other X-ray missions, such as Chandra and XMM-Newton, but its high spectral resolution will allow a new level of detail in observations. Future missions such as Athena will also address similar science questions, providing a synergistic scientific context.

Further Reading:

Further information can be found in scientific publications and NASA's astrophysics mission websites detailing the Arcus concept and mission proposal.