  We report new detections of the two transient ultraluminous X-ray sources
(ULXs) in NGC 5128 from an ongoing series of Chandra observations. Both sources
have previously been observed Lx (2-3)E39 erg/s, at the lower end of the ULX
luminosity range. The new observations allow us to study these sources in the
luminosity regime frequented by the Galactic black hole X-ray binaries (BH
XBs). We present the recent lightcurves of both ULXs. 1RXH J132519.8-430312
(ULX1) was observed at Lx ~ 1E38 erg/s, while CXOU J132518.2-430304 (ULX2)
declined to Lx ~ 2E37 erg/s and then lingered at this luminosity for hundreds
of days. We show that a reasonable upper limit for both duty cycles is 0.2,
with a lower limit of 0.12 for ULX2. This duty cycle is larger than anticipated
for transient ULXs in old stellar populations. By fitting simple spectral
models in an observation with ~50 counts we recover properties consistent with
Galactic BH XBs, but inconclusive as to the spectral state. We utilise quantile
analyses to demonstrate that the spectra are generally soft, and that in one
observation the spectrum of ULX2 is inconsistent with a canonical hard state at
>95% confidence. This is contrary to what would be expected of an accreting
IMBH primary, which we would expect to be in the hard state at these
luminosities. We discuss the paucity of transient ULXs discovered in early-type
galaxies and excogitate explanations. We suggest that the number of transient
ULXs scales with the giant and sub-giant populations, rather than the total
number of XBs.
