Figure: 2-4keV band, 3-PCU, light curve for the 1997-Aug-4 RXTE
observation of MCG-6-30-15. For display purposes, a bin size of 256s
has been used, although 64s bins are used in the analysis presented in
this paper.
RXTE observed MCG-6-30-15 for approximately 
starting on 4-Aug-1997. We retrieved these data from the NASA-HEASARC public archive situated at the Goddard Space Flight Center. Our
data reduction closely parallels that of Lee et al. (1999a) who has studied
the spectral characteristics of this observation. Since, as mentioned in
the introduction, we are interested in the soft X-ray continuum and the
iron line band, the Proportional Counter Array (PCA) is the appropriate
instrument for us to consider. Examining the housekeeping files for this
observation reveals that Proportional Counter Units (PCUs) 3 and 4 suffer
occasional breakdown and shut off. Hence, we do not consider data from
these units and, instead, extracted STANDARD-2 data from PCUs 0-2.
We applied fairly standard faint-source screening criteria to these data:
the source must be at least 
above the Earth's limb (ELV>10), the source must be located within 
of the nominal
pointing position (OFFSET<0.02), there must be at least three PCUs
on (NUM_PCU_ON>2), it has been at least 30 minutes since a
passage of the South Atlantic Anomaly (TIME_SINCE_SAA>30), and
the electron background is not too high (ELECTRON0<0.1). After
application of these screening criteria, approximately 
of `good' data remain. From these data, 2-4keV and 5-7keV light
curves were extracted using 64s bins. We also extracted the 8-15keV
light curve which we will use in Section 3.3.
The background was estimated using the L7-240 background models which are appropriate for faint sources such as AGN. Background light curves were computed and subtracted from the measured light curves in order to form the final background subtracted light curves that we shall use in our study. Figure 1 shows the continuum band (2-4keV) light curves that results from this procedure. For clarity, the light curve shown in this figure has been binned with 256s bins.
Figure 2: Panel (a) shows the structure function for the 2-4keV band data
from MCG-6-30-15 (squares), together with our analytic approximation
(solid line). Panel (b) shows a portion of the 2-4keV light curve (open
squares and thin error bars) together with the reconstructed light curve
(filled circles and heavy error bars).
