RX J1301.9+2747: A Highly Variable Seyfert Galaxy with Extremely Soft
  X-ray Emission
  In this paper we present a temporal and spectral analysis of X-ray data from
the XMM and Chandra observations of the ultrasoft and variable Seyfert galaxy
RX J1301.9+2747. In both observations the source clearly displays two distinct
states in the X-ray band, a long quiescent state and a short flare (or
eruptive) state which differs in count rates by a factor of 5--7. The
transition from quiescent to flare state occurs in 1--2 ks. We have observed
that the quiescent state spectrum is unprecedentedly steep with a photon index
Gamma~7.1, and the spectrum of the flare state is flatter with Gamma~4.4.
X-rays above 2 keV were not significantly detected in either state. In the
quiescent state, the spectrum appears to be dominated by a black body component
of temperature about ~30--40 eV, which is comparable to the expected maximum
effective temperature from the inner accretion disk. The quiescent state
however, requires an additional steep power-law, presumably arising from the
Comptonization by transient heated electrons. Optical spectrum from the Sloan
Digital Sky Survey shows Seyfert-like narrow lines for RX J1301.9+2747, while
the HST imaging reveals a central point source for the object. In order to
precisely determine the hard X-ray component, future longer X-ray observations
are required. This will help constrain the accretion disk model for RX
J1301.9+2747, and shed new light into the characteristics of the corona and
accretion flows around black holes.
