The Chandra Deep Field–North Survey. VIII. X‐Ray Constraints on Spiral Galaxies from 0.4 <z< 1.5

Abstract
We present a statistical X-ray study of spiral galaxies in the Hubble Deep Field-North and its Flanking Fields using the Chandra Deep Field North 1 Ms dataset. We find that approximately L_star galaxies with 0.4 < z < 1.5 have ratios of X-ray to B-band luminosity similar to those in the local Universe, although the data indicate a likely increase in this ratio by a factor of approximately 2-3. We have also determined that typical spiral galaxies at 0.4 < z < 1.5 should be detected in the 0.5--2 keV band in the flux range 3-6 X 10^-18 erg cm^-2 s^-1.Comment: 7 pages, 3 figures, accepted to ApJ, no further change