Spectroscopic variability of NGC5548 and IC4329A on timescales of days to years

Y. Haba$^1$, A. Furuzawa$^1$, T. Okajima$^1$, F. Akimoto$^1$,
K. Yamashita$^1$\newline
K. Misaki$^2$, and H. Kunieda$^2$

$^1$Nagoya University, Nagoya, Aichi, Japan\newline
$^2$ISAS, Sagamihara, Kanagawa, Japan

We present spectral analyses of NGC5548(z=0.017) and IC4329A(z=0.016)
by using data from ASCA observations. Each object is one of the
brightest Seyfert 1 galaxies, and each dataset contains at least one long
observation(\(\sim100\) ksec). Especially, in NGC5548, long
observations were performed twice in 1996 and 1998 with good data
quality. So they are suitable to investigate the spectral feature and
time variability of Seyfert 1 galaxies in detail. 

First we tried to verify the FeK line behavior with various central
luminosity. According to the simple reflection model, it is expected
that the line flux increases when central source becomes
brighter. However there is no significant positive correlation between 
the line intensity and the central luminosity in our data. Moreover,
we find that the line intensity changes between '96 and
'98 observations in spite of same luminosity in both observations. It
is hard to explain these feature with the simple reflection model.        

Second, the absorption structure below 1 keV obtained by ASCA SIS is
well described by two absorption edges, whose energies are
0.685\(^{ 0.010}_{-0.008}\) keV and 0.827\(^{ 0.017}_{-0.012}\) keV. But the ene
rgy of this feature
seems to be a little lower than the edge energy expected OVII (0.739
keV), OVIII (0.871 keV). Furthermore, results of recent high-resolution observat
ion
indicate that this absorption structure is not explained by absorption
edges but well interpreted by many narrow absorption lines. So we will
discuss the discrepancy between ASCA data and Chandra grating data
with plasma code XSTAR.