X-ray Skies with High-Res Eyes -- Imaging the Cosmos with AXIS

Our first summer workshop was held at the Carnegie Institution for Science's main building in downtown Washington, DC 6-7 August 2018. The purpose of this meeting was to explore the cutting edge astrophysics enabled by a high angular resolution X-ray observatory in the next decade, present the AXIS science case to the community, and solicit feedback. More information, including slides from invited and contributed talks on topics related to high spatial resolution X-ray imaging and its connection with the broader astrophysical community, may be found here.

Science Goals

Galaxies Over Cosmic Time

Galaxies are complex systems that evolve dramatically over cosmic time. Their critical constituents – stars, gas and dust, supermassive black holes and dark matter – are strongly coupled to one another and all have critical parameters that can only be studied in the X-ray band. A detailed study of them to high redshifts requires both high angular resolution and high sensitivity.

Feedback in Galaxies

Theoretical models of galaxy formation require physics beyond just gravity and hydrodynamics. This is called “feedback”: the influence of the objects themselves on their formation. For massive galaxies, it is thought that the main cause of feedback is the influence of the supermassive black hole on star formation, either expelling gas from the galaxy or preventing it from falling in.

Black Hole Strong Gravity

If the geometry is just right, gravitational lensing by a foreground galaxy can produce several images of a background quasar, separated by a few arc-seconds or less. Each image then flickers due to microlensing by individual stars within the lensing galaxy. A statistic analysis of this flicker reveals information about the micro-arcsecond scale structures of the inner accretion disk.

Dual AGN

The general theory of structure formation predicts that mergers are a major component of galaxy growth and evolution. It has long been predicted that when the galaxies merge, so should their black holes. Little information is known about the occurrence rate of dual AGN for a large sample of objects covering a wide range in mass, luminosity and nature of the host galaxy.

The High-Redshift Universe

Only a small number of X-ray AGNs have been directly detected beyond z>5. AXIS has the potential to generate much larger samples of z>5 AGNs, allowing the study of how the AGN luminosity function changes at high redshifts and comparison with the star formation history. This is a key measurement in understanding the co-evolution of black holes and their host galaxies.

Observatory Science

We hope the community will join in the fun! This includes the detailed study of star clusters, resolving supernova remnants in nearby galaxies, the astrophysics of jets, pulsar wind nebulae, star formation regions in the local group, cluster cooling fronts, galaxy interactions, bubbles in clusters, ram pressure stripping of galaxies in groups and clusters and beyond.



The X-ray mirror combines large throughput with high angular resolution throughout the field-of-view. Thin shell mirror technology is being developed at NASA's Goddard Space Flight Center and provides the needed combination of properties at a reasonable mass and cost.
Learn more here.


The focal plane detector includes an array of CCDs or related devices covering a field-of-view of 15’ field or larger. Small pixels and fast readout allow for the sampling of the point-spread function and significantly reduces pile-up from bright point sources.
Learn more here.

Mission Overview

AXIS (Advanced X-ray Imaging Satellite) is a NASA Probe Mission Concept designed to be the premier high angular resolution X-ray mission of 2020s. The need for sub-arcsecond resolution in astrophysics is evident across the entire electromagnetic spectrum, and is essential for resolving the critical physical scales of virtually all classes of objects and for extending such studies to the highest redshift. AXIS will follow in the footsteps of the spectacularly successful Chandra X-ray Observatory with similar or higher angular resolution and ~10x Chandra count rates.

Read the full Probe Mission Concept Proposal here.

AXIS Science Simulation Resources

AXIS obervations may be simulated using simx. To use the most up-to-date response and background files download this zip file.


For details about AXIS technology and science, look to these presentations.
All presentations on specific science topics are available at our Presentations Page.

The Advanced X-ray Imaging Satellite (Presentation at SPIE Astronomical Telescopes + Instrumentation 2018) - Richard Mushotzky

AXIS: A Probe Class Next Generation High Angular Resolution X-ray Imaging Satellite (arXiv version of Proceedings of 2018 SPIE talk) - Richard Mushotzky

AXIS Science Talk at Los Alamos National Laboratory - Richard Mushotzky

AXIS Technical Talk at Los Alamos National Laboratory - Richard Mushotzky

AXIS Presentation at HEAD 2017 - Erin Kara and Eric Miller

The AXIS Team

PI: Richard Mushotzky

Our first team meeting at the University of Maryland, College Park. June 14-15, 2017.

List of Attendees (left to right): Mike Loewenstein, Andy Ptak, Randall Smith, Lynne Valencic, George Chartas, Will Zhang, Maxim Markevitch, Richard Mushotzky, Brian Morsony, Francesco Tombesi, Rob Petre, Eric Miller, Helen Russell, Chris Reynolds and Erin Kara.

Not Pictured: David Burrows, Lia Corrales, Andy Fabian, Catherine Grant, Edmund Hodges-Kluck, Mike Koss, Jon Miller, John Mulchaey, Stephen Walker, and Hiroya Yamaguchi.

Contact Us

If you have ideas, suggestions or comments for AXIS, please tell us what you think!


RFI documents.