IFC/CNR Ringberg, April 2-4, 2002 PSF in-flight calibration - PN PSF in-flight calibration for PN camera Simona Ghizzardi Silvano Molendi
Jan 01, 2016
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
PSF in-flight calibration
for PN camera
Simona Ghizzardi
Silvano Molendi
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
ENERGY RANGES:
0.3 keV [200-400] eV
0.6 keV [400-800] eV
1.0 keV [800-1200] eV
1.8 keV [1200-2400] eV
3.7 keV [2400-5000] eV
6.5 keV [5000-8000] eV
10.0 keV [8000-12000] eV
DATA SAMPLE:
- 110 SOURCES (TARGET) included
OFF-AXIS ANGLES: from on-axis position up to 10 arcmin
- most of them are observed within 2 arcmin.
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
We adopt the same procedure and the same algorithm used for the two MOS cameras.
The pixel size of the PSF images is taken 1.1” .
According to the MOS results, the profile of the PSF is well represented by a King model:
PSF = KING + BKG
Analysis procedure and PSF model
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
King profile
core slope
Two shape parameters: core radius (rc) and slope ()
IT CAN BE INTEGRATED ANALYTICALLY IN rdr!!!
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
We merged the observations having
the same source target
the same pointing position
different filters and/or operating mode --->
---> different pile-up levels
The centroid is determined accounting for the mask of the detector
For each curve a good fitting range must be defined (points suffering
for pile-up must be excluded).
Building the radial profile
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
Algorithm for the averaged radial profile
•Energy selection and pattern (0-12) selection
BASIC METHOD
We bin the image (with larger bins at larger radii)
RADIAL PROFILE: dN/dA (the area is not 2r dr because of the mask)
each (squared) pixel is assigned to the (round) bin to which its CENTER belongs
for these pixels it works fairly
these pixels belong to two different bins in comparable fractions
the effect is less important at larger radiiADDITIONAL RECIPE ADDED TO THE BASIC PROCEDURE
We enclose each pixel in a circle.
If the circle is fully enclosed in the bin then the pixel is too.
If the circle is partly enclosed in another bin, the pixel may belong to two bins: we divide such pixels in NSUBPIXELS
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
The physical pixel size is 4.1”, not much smaller than
the core radius of the PSF.
The calibration of the core is quite tricky
The frame time is smaller than the MOS one.
The pile-up effect is less important
The effective area is larger than the MOS one.
Good statistics
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
In order to enhance the statistics, we fit simultaneously the different curves with different pile-up levels
PSF = King + BKG
e rc are the same
for each curve
BKG and the normalization
are different for each curve
for each energy and off-axis angle we derive and rc.
Fitting the radial profiles
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
rc = rc(E, )
= (E, )
SLOPE:
IT HAS A ROUGHLY CONSTANT
BEHAVIOR EVEN IF THE 2-D
BEST FIT DECREASES
FOR OFF-AXIS ANGLES
INCREASING.
CORE:CORE:
THE LINEAR DECREASING BEHAVIOR IS NOT WELL THE LINEAR DECREASING BEHAVIOR IS NOT WELL REPRESENTED BY THE 2-D FIT.REPRESENTED BY THE 2-D FIT.
2-D FIT:
THE 2-D FIT IS DRIVEN BY THE ON-AXIS POINTS.THE 2-D FIT IS DRIVEN BY THE ON-AXIS POINTS.
0.3 keV
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
rc = rc(E, )
= (E, )
SLOPE:
IT HAS A ROUGHLY CONSTANT
BEHAVIOR EVEN IF THE 2-D
BEST FIT DECREASES
FOR OFF-AXIS ANGLES
INCREASING.
CORE:CORE:
THE LINEAR DECREASING BEHAVIOR IS NOT WELL THE LINEAR DECREASING BEHAVIOR IS NOT WELL REPRESENTED BY THE 2-D FIT.REPRESENTED BY THE 2-D FIT.
2-D FIT:
THE 2-D FIT IS DRIVEN BY THE ON-AXIS POINTS.THE 2-D FIT IS DRIVEN BY THE ON-AXIS POINTS.
0.6 keV
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
rc = rc(E, )
= (E, )
SLOPE:
IT HAS A ROUGHLY CONSTANT
BEHAVIOR EVEN IF THE 2-D
BEST FIT DECREASES
FOR OFF-AXIS ANGLES
INCREASING.
CORE:CORE:
THE LINEAR DECREASING BEHAVIOR IS NOT WELL THE LINEAR DECREASING BEHAVIOR IS NOT WELL REPRESENTED BY THE 2-D FIT.REPRESENTED BY THE 2-D FIT.
2-D FIT:
THE 2-D FIT IS DRIVEN BY THE ON-AXIS POINTS.THE 2-D FIT IS DRIVEN BY THE ON-AXIS POINTS.
1.0 keV
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
rc = rc(E, )
= (E, )
SLOPE:
IT HAS A ROUGHLY CONSTANT
BEHAVIOR EVEN IF THE 2-D
BEST FIT DECREASES
FOR OFF-AXIS ANGLES
INCREASING.
CORE:CORE:
THE LINEAR DECREASING BEHAVIOR IS NOT WELL THE LINEAR DECREASING BEHAVIOR IS NOT WELL REPRESENTED BY THE 2-D FIT.REPRESENTED BY THE 2-D FIT.
2-D FIT:
THE 2-D FIT IS DRIVEN BY THE ON-AXIS POINTS.THE 2-D FIT IS DRIVEN BY THE ON-AXIS POINTS.
1.8 keV
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
rc = rc(E, )
= (E, )
SLOPE:
IT HAS A ROUGHLY CONSTANT
BEHAVIOR EVEN IF THE 2-D
BEST FIT DECREASES
FOR OFF-AXIS ANGLES
INCREASING.
CORE:CORE:
THE LINEAR DECREASING BEHAVIOR IS NOT WELL THE LINEAR DECREASING BEHAVIOR IS NOT WELL REPRESENTED BY THE 2-D FIT.REPRESENTED BY THE 2-D FIT.
2-D FIT:
THE 2-D FIT IS DRIVEN BY THE ON-AXIS POINTS.THE 2-D FIT IS DRIVEN BY THE ON-AXIS POINTS.
3.7 keV
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
rc = rc(E, )
= (E, )
SLOPE:
IT HAS A ROUGHLY CONSTANT
BEHAVIOR EVEN IF THE 2-D
BEST FIT DECREASES
FOR OFF-AXIS ANGLES
INCREASING.
CORE:CORE:
THE LINEAR DECREASING BEHAVIOR IS NOT WELL THE LINEAR DECREASING BEHAVIOR IS NOT WELL REPRESENTED BY THE 2-D FIT.REPRESENTED BY THE 2-D FIT.
2-D FIT:
THE 2-D FIT IS DRIVEN BY THE ON-AXIS POINTS.THE 2-D FIT IS DRIVEN BY THE ON-AXIS POINTS.
6.5 keV
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
rc = rc(E, )
= (E, )
SLOPE:
IT HAS A ROUGHLY CONSTANT
BEHAVIOR EVEN IF THE 2-D
BEST FIT DECREASES
FOR OFF-AXIS ANGLES
INCREASING.
CORE:CORE:
THE LINEAR DECREASING BEHAVIOR IS NOT WELL THE LINEAR DECREASING BEHAVIOR IS NOT WELL REPRESENTED BY THE 2-D FIT.REPRESENTED BY THE 2-D FIT.
2-D FIT:
THE 2-D FIT IS DRIVEN BY THE ON-AXIS POINTS.THE 2-D FIT IS DRIVEN BY THE ON-AXIS POINTS.
10. keV
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
rc = rc(E, )
= (E, )
SLOPE: SLOPE:
IT HAS A ROUGHLY CONSTANTIT HAS A ROUGHLY CONSTANT
BEHAVIOR EVEN IF THE 2-D BEHAVIOR EVEN IF THE 2-D
BEST FIT DECREASES BEST FIT DECREASES
FOR OFF-AXIS ANGLES FOR OFF-AXIS ANGLES
INCREASING. INCREASING.
CORE:
THE LINEAR DECREASING BEHAVIOR IS NOT WELL REPRESENTED BY THE 2-D FIT.
2-D FIT:
THE 2-D FIT IS DRIVEN BY THE ON-AXIS POINTS.THE 2-D FIT IS DRIVEN BY THE ON-AXIS POINTS.
1.0 keV
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
rc = rc(E, )
= (E, )
SLOPE: SLOPE:
IT HAS A ROUGHLY CONSTANTIT HAS A ROUGHLY CONSTANT
BEHAVIOR EVEN IF THE 2-D BEHAVIOR EVEN IF THE 2-D
BEST FIT DECREASES BEST FIT DECREASES
FOR OFF-AXIS ANGLES FOR OFF-AXIS ANGLES
INCREASING. INCREASING.
CORE:
THE LINEAR DECREASING BEHAVIOR IS NOT WELL REPRESENTED BY THE 2-D FIT.
2-D FIT:
THE 2-D FIT IS DRIVEN BY THE ON-AXIS POINTS.THE 2-D FIT IS DRIVEN BY THE ON-AXIS POINTS.
1.8 keV
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
rc = rc(E, )
= (E, )
SLOPE: SLOPE:
IT HAS A ROUGHLY CONSTANTIT HAS A ROUGHLY CONSTANT
BEHAVIOR EVEN IF THE 2-D BEHAVIOR EVEN IF THE 2-D
BEST FIT DECREASES BEST FIT DECREASES
FOR OFF-AXIS ANGLES FOR OFF-AXIS ANGLES
INCREASING. INCREASING.
CORE:
THE LINEAR DECREASING BEHAVIOR IS NOT WELL REPRESENTED BY THE 2-D FIT.
2-D FIT:
THE 2-D FIT IS DRIVEN BY THE ON-AXIS POINTS.
3.7 keV
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
BINNING
Data are not well represented by the 2-D data because they present a very large scatter.
The 2-D fit ( but also each 1-D fit for any fixed energy) is completely driven by the on-axis data.
We bin on the off-axis angle variable with bin 12” wide.
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
rc = rc(E, )
= (E, )
BINS for off axis angle: 12”
SLOPE:
IT HAS A ROUGHLY CONSTANT
BEHAVIOR
CORE:CORE:
IT LINEARLY DECREASES FOR IT LINEARLY DECREASES FOR
INCREASING OFF AXIS ANGLESINCREASING OFF AXIS ANGLES
2-D FIT:
0.3 keV
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
rc = rc(E, )
= (E, )
BINS for off axis angle: 12”
SLOPE:
IT HAS A ROUGHLY CONSTANT
BEHAVIOR
CORE:CORE:
IT LINEARLY DECREASES FOR IT LINEARLY DECREASES FOR
INCREASING OFF AXIS ANGLESINCREASING OFF AXIS ANGLES
2-D FIT:
0.6 keV
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
rc = rc(E, )
= (E, )
BINS for off axis angle: 12”
SLOPE:
IT HAS A ROUGHLY CONSTANT
BEHAVIOR
CORE:CORE:
IT LINEARLY DECREASES FOR IT LINEARLY DECREASES FOR
INCREASING OFF AXIS ANGLESINCREASING OFF AXIS ANGLES
2-D FIT:
1.0 keV
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
rc = rc(E, )
= (E, )
BINS for off axis angle: 12”
SLOPE:
IT HAS A ROUGHLY CONSTANT
BEHAVIOR
CORE:CORE:
IT LINEARLY DECREASES FOR IT LINEARLY DECREASES FOR
INCREASING OFF AXIS ANGLESINCREASING OFF AXIS ANGLES
2-D FIT:
1.8 keV
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
rc = rc(E, )
= (E, )
BINS for off axis angle: 12”
SLOPE:
IT HAS A ROUGHLY CONSTANT
BEHAVIOR
CORE:CORE:
IT LINEARLY DECREASES FOR IT LINEARLY DECREASES FOR
INCREASING OFF AXIS ANGLESINCREASING OFF AXIS ANGLES
2-D FIT:
3.7 keV
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
rc = rc(E, )
= (E, )
BINS for off axis angle: 12”
SLOPE:
IT HAS A ROUGHLY CONSTANT
BEHAVIOR
CORE:CORE:
IT LINEARLY DECREASES FOR IT LINEARLY DECREASES FOR
INCREASING OFF AXIS ANGLESINCREASING OFF AXIS ANGLES
2-D FIT:
6.5 keV
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
rc = rc(E, )
= (E, )
BINS for off axis angle: 12”
SLOPE:
IT HAS A ROUGHLY CONSTANT
BEHAVIOR
CORE:CORE:
IT LINEARLY DECREASES FOR IT LINEARLY DECREASES FOR
INCREASING OFF AXIS ANGLESINCREASING OFF AXIS ANGLES
2-D FIT:
10. keV
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
rc = rc(E, )
= (E, )
BINS for off axis angle: 12”
SLOPE: SLOPE:
IT HAS A ROUGHLY CONSTANTIT HAS A ROUGHLY CONSTANT
BEHAVIORBEHAVIOR
CORE:
IT LINEARLY DECREASES FOR
INCREASING OFF AXIS ANGLES
2-D FIT:
1.0 keV
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
rc = rc(E, )
= (E, )
BINS for off axis angle: 12”
SLOPE: SLOPE:
IT HAS A ROUGHLY CONSTANTIT HAS A ROUGHLY CONSTANT
BEHAVIORBEHAVIOR
CORE:
IT LINEARLY DECREASES FOR
INCREASING OFF AXIS ANGLES
2-D FIT:
1.8 keV
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
rc = rc(E, )
= (E, )
BINS for off axis angle: 12”
SLOPE: SLOPE:
IT HAS A ROUGHLY CONSTANTIT HAS A ROUGHLY CONSTANT
BEHAVIORBEHAVIOR
CORE:
IT LINEARLY DECREASES FOR
INCREASING OFF AXIS ANGLES
2-D FIT:
3.7 keV
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
Profiles using the best fit values
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
Profiles using the best fit values
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
WHY SUCH A SCATTER ?
Out of time events can affect the slope of the profile
Pile up is less evident in the PN data. Are we neglecting a pile up effect?
Centroiding is very difficult because of the large size of the pixels. This makes the determination of the core uncertain especially for the Small Window op. mode.
…TO BE INVESTIGATED
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
FULL FRAME
SMALL WINDOW
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
WHY SUCH A SCATTER ?
Out of time events can affect the slope of the profile
Pile up is less evident in the PN data. Are we neglecting a pile up effect?
Centroiding is very difficult because of the large size of the pixels. This makes the determination of the core uncertain especially for the Small Window op. mode.
…TO BE INVESTIGATED
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
WHY SUCH A SCATTER ?
Out of time events can affect the slope of the profile
Pile up is less evident in the PN data. Are we neglecting a pile up effect?
Centroiding is very difficult because of the large size of the pixels. This makes the determination of the core uncertain especially for the Small Window op. mode.
…TO BE INVESTIGATED
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
King Core Radius for PN
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
King Slope for PN
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
BEST FIT VALUES
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
ENCIRCLED ENERGY FRACTION
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
Range of Application
IFC/CNR Ringberg, April 2-4, 2002
PSF in-flight calibration - PN
CONCLUSIONS
By using a large set of data we modeled the PSF profile with a King function and provided the best fit values of the core and of the slope as functions of the energy and of the off-axis angle.
To be done …
We must include in the sample some other off-axis sources to enlarge the region of the range of application.
Check on :
evaluation of the background in the Small Window measures
out of time events
pile-up
centroiding procedures
in order to reduce the scatter of the points