In November 2023 the CXC issued the Chandra Legacy Program (CLP) call for white papers to identify science challenges for which the capabilities of Chandra are absolutely required. A committee reviewed the white papers and recommended two initiatives, and a Call for Chandra Legacy Program Proposals for these initiatives was issued in February 2023.
Based on the review of the submitted proposals, the following programs were selected for the Chandra Legacy Program:
For Initiative I: Probing the Physics of Baryon Cycles and Feedback using Deep Observations of Nearby Galaxies, the selected proposal is:
Abstract:
In star-forming galaxies, X-rays offer critical probes of binary systems, massive-star remnants, and the hot phase of the interstellar medium (ISM), crucial components for understanding stellar evolution, feedback, and galactic ecosystems. We propose to obtain Chandra observations that, together with archival data, cover all 74 galaxies from the Physics at High Angular resolution in Nearby GalaxieS (PHANGS) survey to accompany high-resolution data from AstroSAT, HST, VLT/MUSE, ALMA, JWST. Our survey will link X-ray sources to host stellar and nebular environments, yielding peerless constraints on the formation timescales and properties of a variety of X-ray binary populations, feedback energetics from massive stars, and the connection between hot gas and the other ISM phases. The resulting large Chandra dataset will be used to address an array of additional astrophysical problems and will have enduring legacy value as future observatories will continually target PHANGS galaxies.
PI: Smita Mathur (Ohio State University)
Targets:
Time Awarded: 2.9 Ms
For Initiative II: Deep Observation of a Galaxy Cluster to Understand Key Physical Processes, the selected proposal is:
Abstract:
A further 3Ms deep ACIS-I image of the Perseus cluster is proposed to test how feedback energy propagates across the core. Small-scale ripples in the existing deep ACIS-S imaging could be due to sound waves or turbulence, which are distinguished by whether they are adiabatic or isobaric. This can be achieved using hardness ratios from bands above and below 4 keV in the total 3.9Ms central image at >5sigma. Cold fronts and outer turbulence are likely driven by sloshing. The final very deep image will yield a step change in understanding the transport and dissipation of energy within the X-ray brightest cool core in the Sky, with important ramifications for understanding AGN feedback from the most massive central galaxies in cool core clusters and a legacy for cluster core studies.
PI: Andrew Fabian (University of Cambridge)
Time Awarded: 3.0 Ms
The programs will run in parallel over the course of Cycles 26 and 27, which nominally begin in January 2025 and January 2026, respectively.