NASA ASTRA White Paper : A Chandra Successor in the 2030s

C. S. Reynolds; E. Hodges-Kluck; E. A. Kara; M. Koss; K. Madsen; E. Miller; B. Williams; S. Allen; M. Bautz; K. Burdge; N. Cappelluti; B. Cenko; L. Corrales; A. Falcone; A. Foord; D. Haggard; L. Lopez; R. Mushotzky; A. Ptak; H. Russell; S. Safi-Harb; K. Stassun

arXiv · 2610.00475

NASA ASTRA White Paper : A Chandra Successor in the 2030s

View original source ↗Read source document ↗Export metadata ↓

Abstract

Chandra established that soft X-ray spectral imaging with approximately 1 arcsec angular resolution is an essential tool for almost every area of astrophysics, from the early Universe to ice chemistry in protoplanetary disks. While Chandra continues to deliver groundbreaking science, it lacks the sensitivity to be the counterpart to JWST, Roman, Rubin, LISA, ngVLA, ALMA, IceCube, NewAthena, ELT, and other upcoming large facilities. Here we highlight the scientific potential of a Chandra successor with >10x higher sensitivity and >50x survey speed. While the scientific reach of such a mission is very broad, we showcase four high-priority science questions that require these capabilities -- How did supermassive black holes form?, How does stellar and AGN feedback work in galaxies?, How does high-energy stellar activity affect exoplanet atmospheres? and, How do black holes merge? A Chandra successor in the 2030s would also demonstrate the X-ray mirror technology for a future flagship and sustain the US high energy astrophysics workforce until that flagship launches. We outline the science-instrument trade space by sketching three missions based on the NASA Probe concept study report for the Advanced X-ray Imaging Satellite (AXIS): AXIS-Deep, AXIS-Classic, and AXIS-Fast, highlighting a breakthrough science case for each and listing others that drive the design.

Explore related subjects

astro-ph.IM astro-ph.HE

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

C. S. Reynolds, E. Hodges-Kluck, E. A. Kara, M. Koss, K. Madsen, E. Miller, B. Williams, S. Allen, M. Bautz, K. Burdge, N. Cappelluti, B. Cenko, L. Corrales, A. Falcone, A. Foord, D. Haggard, L. Lopez, R. Mushotzky, A. Ptak, H. Russell, S. Safi-Harb, K. Stassun. 2026-09-30. NASA ASTRA White Paper : A Chandra Successor in the 2030s. https://arxiv.org/abs/2610.00475

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

NEXUS: Quick Release Notes

NEXUS is a JWST Multi-Cycle (Cycles 3-5) GO Treasury imaging and spectroscopic survey around the North Ecliptic Pole during 2024-2028. It contains two overlapping tiers in depth and area coverage. The Wide tier ($\sim 400~{\rm arcmin}^2$) performs NIRCam/WFSS 2.4-5 $μ$m grism spectroscopy with three annual epochs over 3 years (final spectral continuum ${\rm S/N/pixel>3}$ at F444W $<22.2$), accompanied by NIRCam multi-band imaging in F090W, F115W, F150W, F200W, F356W and F444W. The Deep tier ($\sim 50~{\rm arcmin}^2$) performs high-multiplexing NIRSpec 0.54-5.5 $μ$m MOS/PRISM spectroscopy for ~10,000 targets in total, over 18 epochs with a 2-month cadence, along with F200W+F444W NIRCam imaging for each epoch. Parallel imaging observations with MIRI and additional NIRCam filters are also performed within the Wide and Deep tiers. The primary data covering the Deep tier (including NIRCam imaging, NIRSpec/MSA spectra, and vetted MSA spectroscopic redshifts) are released in regular Quick Data Releases to facilitate follow-up studies. This evolving document describes the MSA targeting information and observing status for each of the 18 Deep epochs, which started in May 2025 and continue on the regular 2-month cadence. We also describe the content and caveats of the quick release data and report selected cases of diverse scientific interests.

astro-ph.IM↗

arXiv2026

Operating the Fabry-Pérot systems of the European Solar Telescope in multi-aperture mode

We discuss how to optimise the science output of the European Solar Telescope (EST), when used without the wide-field compensation for high-altitude seeing that the EST multi conjugate adaptive optics (MCAO) system will offer. Without MCAO, in particular with the Sun at low elevations or when observing at short wavelengths, high-altitude seeing will strongly attenuate the signal at high spatial frequencies over almost the entire 1 arc min science field-of-view (FOV) of EST. We propose to provide EST with an optional multi-aperture mode, by optically segmenting the 4.2 m aperture into six 1.4 m sub-apertures. This pushes down the root mean square wavefront errors from the high altitude seeing to levels that can more reliably be compensated for with conventional ground-layer adaptive optics and post processing of restored images. This will provide the sustained stable high image quality over a large FOV, needed for obtaining time sequences of spectropolarimetric data. The multi-aperture mode is implemented with low-cost modifications of the camera lenses of the three Fabry-Perot systems that will be used to cover the wavelength range 380-860 nm. Switching between the full-aperture and multi-aperture modes can be done quickly and independently for the three FPI systems. This allows flexible optimisation of EST, taking into account the daily variability and wavelength dependence of seeing. Providing EST with a multi-aperture option represents a value-added aspect that has no negative impact on the EST optical systems or on the FPI systems. It provides a powerful and flexible option that has the potential of significantly improving the quality and amount of its science data before MCAO is operational. We perform simulations and image reconstructions of simulated data to demonstrate the benefits of the multi-aperture option, and provide an optical design to demonstrate its feasibility.

astro-ph.IM↗

arXiv2026

FARSim: a fast RF-chain-aware trigger-screening surrogate for radio detection of ultra-high-energy cosmic rays

Radio arrays provide a scalable route to detecting extensive air showers from ultra-high-energy cosmic rays, but trigger studies for candidate layouts are expensive when every energy, arrival direction, core position and trigger configuration is evaluated with full radio simulations. We present FARSim, a fast surrogate framework that reuses a reduced library of ZHAireS reference footprints to reconstruct ground-plane radio emission and to estimate trigger-relevant observables. The method combines vector geomagnetic and charge-excess field decomposition, geomagnetic-angle and energy scaling, geometrical projection, contour-based core sampling and event-rate integration. We evaluate an independent validation set of 1999 ZHAireS showers; 941 events satisfy the predefined radial-support and station-count requirements and yield a median event-level relative RMSE of 9.4% and a median Pearson coefficient $r_{\mathrm{P}}=0.965$ for the reconstructed geomagnetic lateral profiles. We further extend the peak-field surrogate to time-domain electric-field synthesis by combining the predicted three-component peak-field vector with geometry-dependent normalized pulse templates. Propagating these traces through an RF-chain response enables voltage-domain threshold and L1-trigger diagnostics. When evaluated at the true peak amplitude, the time-domain extension reaches a median vector-waveform $R^2$ of 0.986 over 2112 ZHAireS traces held out from pulse-shape model fitting. FARSim is therefore intended as a rapid, physics-informed screening layer for array-layout and trigger studies; absolute exposure predictions and detector commissioning remain the role of full end-to-end simulations.

astro-ph.IM↗