A 78 Day X-ray Period Detected from NGC 5907 ULX1 by Swift

D. J. Walton, F. Fuerst, M. Bachetti +12

We report the detection of a $78.1\pm 0.5$ day period in the X-ray lightcurve of the extreme ultraluminous X-ray source NGC 5907 ULX1 ($L_{\mathrm{X},\mathrm{peak}}\sim 5\times 10^{40}$ erg s$^{-1…