AXIS: A Probe Class Next Generation High Angular Resolution X-ray Imaging Satellite

Abstract

AXIS is a probe-class concept under study for submission to the 2020 Decadal survey. AXIS will extend and enhance the science of high angular resolution X-ray imaging and spectroscopy in the next decade with ∼ 0.4 angular resolution over a 24 × 24 field of view, with 0.3" in the central 14 × 14 , and an order of magnitude more collecting area than Chandra in the 0.3−12 keV band with a cost consistent with a probe.These capabilities are made possible by precision-polished lightweight single-crystal silicon optics achieving both high angular resolution and large collecting area, and next generation small-pixel silicon detectors adequately sampling the point spread function and allowing timing science and preventing pile up with high read-out rate. We have selected a low earth orbit to enable rapid target of opportunity response, similar to Swift, with a high observing efficiency, low detector background and long detector life.The combination opens a wide variety of new and exciting science such as: (1) measuring the event horizon scale structure in AGN accretion disks and the spins of supermassive black holes through observations of gravitationally-microlensed quasars; (ii) determining AGN and starburst feedback in galaxies and galaxy clusters through direct imaging of winds and interaction of jets and via spatially resolved imaging of galaxies at high-z; (iii) fueling of AGN by probing the Bondi radius of over 20 nearby galaxies; (iv) hierarchical structure formation and the SMBH merger rate through measurement of the occurrence rate of dual AGN and occupation fraction of SMBHs; (v) advancing SNR physics and galaxy ecology through large detailed samples of SNR in nearby galaxies; (vi) measuring the Cosmic Web through its connection to cluster outskirts; (vii) a wide variety of time domain science including rapid response to targets of opportunity.With a nominal 2028 launch, AXIS benefits from natural synergies with the ELTs, LSST, ALMA, WFIRST and ATHENA. The AXIS team welcomes input and feedback from the community in preparation for the 2020 Decadal review.

Exploring the Local Black Hole Mass Function below 106 Solar Masses

“…In general, conservative occupation fraction values can be recovered with ∼5% accuracy with ∼5,000 galaxies (adopting an M -dependent sensitivity reduces the number of required targets to ∼3,000; Hodges- Kluck et al, submitted). This can be realistically achieved by an X-ray instrument with large collecting area and sub-arcsec imaging capabilities over a wide-field of view, such as those envisaged for the Lynx X-ray Surveyor (Gaskin et al 2018) mission, or the Advanced X-ray Imaging Satellite (Mushotzky 2018) probe. The effect of a highly improved occupation accuracy on the BHMF is illustrated by the right panel of Figure 3 for three "pessimistic" input values of M ,0 (i.e., all implying lower occupation than the current median value of 8.17, shown in Figure 1 as a cross).…”

Intermediate-Mass Black Holes in Extragalactic Globular Clusters

“…The Chandra X-ray mission and its proposed successors, Lynx [15] and the Advanced X-ray Imaging Satellite [28], feature spatial resolutions of 300 to 500 mas. These will suffice to roughly localize X-ray sources to GCs out to a distance of 25 Mpc.…”