We report the discovery of a narrow-line QSO ( NLQSO ) RX J1334.2+3759 with a steep soft X-ray spectrum .
Soft X-ray emission from the NLQSO is highly variable .
Changes in the intensity by a factor of \sim 2 have been detected in the ROSAT PSPC observations of RX J1334.2+3759 on time scales of \sim 20000 - 40000 { ~ { } s } .
Rapid variability events have also been observed from RX J1334.2+3759 .
The most extreme variable event has \frac { \Delta L } { \Delta t } = ( 1.95 \pm 1.02 ) \times 10 ^ { 42 } { ~ { } erg~ { } s ^ { -2 } } corresponding to a change in intensity by a factor of \sim 4 within \la 400 { ~ { } s } .
The PSPC spectra of the NLQSO can be well represented by a power-law of photon index , \Gamma _ { X } \sim 3.8 modified by an absorbing column local to the source ( \Delta \mbox { $ { N _ { H } } $ } \sim 3.3 \times 10 ^ { 20 } \mbox { $~ { } { cm } ^ { -2 } $ } ) over and above that due to our own Galaxy ( { \mbox { $ { N _ { H } } $ } } = 7.9 \times 10 ^ { 19 } \mbox { $~ { } { cm } ^ { -2 } $ } ) .
The intrinsic soft X-ray luminosity of RX J1334.2+3759 is estimated to be \sim 2.2 \times 10 ^ { 44 } { ~ { } erg~ { } s ^ { -1 } } in the energy band of 0.1 - 2.0 { ~ { } keV } .
The optical spectrum of RX J1334.2+3759 is typical of the NLS1 galaxies showing strong Balmer H \beta , H \alpha , and forbidden line of [ O III ] \lambda 5007 .
Fe II multiplets , usually present in the optical spectra of NLS1 galaxies , are also detected from RX J1334.2+3759 .
Decomposition of the H \beta and H \alpha line profiles shows the presence of narrow ( FWHM \sim 880 { ~ { } km~ { } s ^ { -1 } } ) and broad ( FWHM \sim 2850 { ~ { } km~ { } s ^ { -1 } } ) components in the spectrum of RX J1334.2+3759 .
The narrow-line region of RX J1334.2+3759 appears to be significantly different from those of normal Seyfert galaxies .
A possible explanation for the observed properties of the narrow line region and the broad line region is suggested in terms of density enhancements .