chandra x-ray observatory cxc paul plucinsky february 2005 1 a comparison of spectral fit results of...
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Chandra X-Ray Observatory CXC
Paul Plucinsky February 20051
A Comparison of Spectral Fit Results A Comparison of Spectral Fit Results of E0102 from the Chandra and of E0102 from the Chandra and
XMM CCDsXMM CCDs
Paul Plucinsky & Paul Plucinsky & Joseph DePasquale Joseph DePasquale
Chandra X-Ray Observatory CXC
Paul Plucinsky February 20052
Other Contributors to this EffortOther Contributors to this Effort
CXC: R. Edgar , N. Schulz, A. Vikhilin
MIT: K. Flanagan, D. Dewey, lots of help from MIT ACIS team
Chandra X-Ray Observatory CXC
Paul Plucinsky February 20053
Why Use E0102 as a Calibration Source for the CCDs?Why Use E0102 as a Calibration Source for the CCDs?
• Well-characterized spectrum, both the Chandra HETG and XMM RGS have observed the object• The spectrum is relatively simple by astrophysical standards, no or very little Fe, strong lines of O, Ne, and Mg• Extended source so pileup effects are minimized• Constant source• The O and Ne lines sample an energy range in which the on-board calibration source does not have strong lines• Low-energy part of the bandpass is always a challenge to calibrate
Chandra X-Ray Observatory CXC
Paul Plucinsky February 20054
Spectral Model: Calibration vs. AstrophysicsSpectral Model: Calibration vs. Astrophysics
• Primary Objectives are to measure the gain, the spectral redistribution function, and detection efficiency in the 0.5 -2.0 keV range• Our immediate concern is to develop a model useful for calibration, not to develop an astrophysically-meaningful model, • We use a model consisting of 24 Gaussians for the lines identified by the HETG and RGS, a bremsstrahlung for the continuum, and a two component absorption (Galactic and SMC)• Line energies are fixed at the true values and the widths of the Gaussians are fixed at zero, so the only parameter which varies is the normalization• Constrain the ratio of the OVII For (561 eV)/O VII Res (574 eV) to 0.58 based on HETG and OVII (665 eV)/ OVIII Ly-alpha (654 eV) to 0.1368 (ratios from Flanagan et al. 2004)
Chandra X-Ray Observatory CXC
Paul Plucinsky February 20055
ACIS-Specific Calibration Issues:ACIS-Specific Calibration Issues:
• CTI Correction for the FI CCDs• Time-dependent gain correction for both BI and FI CCDs• QE correction for the S3 CCD (summer 2004)• Time-dependent and spatial-dependent correction for the contamination (aka ``The Marshall Layer’’)• We used CIAO 3.2 and CALDB 3.0.0 (released Dec 2004)
XMM Data:XMM Data:
• Provided by Andy Read (16 MOS1/MOS2) and Michael Smith (1 each MOS1/MOS2/PN)
Chandra Data:Chandra Data:• 44 observations on I3 and 20 observations on S3, roughly once every 6 months• Data (spectra, rmfs, & arfs) available at: “http:cxc.harvard.edu/acis/E0102/splash.html” Available for any one to download, please do if you would like the data !!
Chandra X-Ray Observatory CXC
Paul Plucinsky February 20056
Gratuitous Pretty Pictures of E0102 Gratuitous Pretty Pictures of E0102
S3 Summed Data ~100 ksS3 Summed Data ~100 ks True Color ImageTrue Color Image
Chandra X-Ray Observatory CXC
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S3(BI)
Chandra X-Ray Observatory CXC
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OVII triplet
OVIII Ly-aNe IX triplet
Ne X Ly-a
Mg XI triplet
S3(BI)
Chandra X-Ray Observatory CXC
Paul Plucinsky February 20059
OVII triplet
OVIII Ly-a
Ne IX triplet Ne X Ly-a
Mg XI Ly-a
I3(FI)
Chandra X-Ray Observatory CXC
Paul Plucinsky February 200510
Chandra X-Ray Observatory CXC
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Chandra X-Ray Observatory CXC
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MOS 1
MOS 2
Thick filter
Large Window
Chandra X-Ray Observatory CXC
Paul Plucinsky February 200513
MOS 1
MOS 2
Thick Filter
Large Window
Chandra X-Ray Observatory CXC
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PN
MOS 1
MOS 2
Thick Filter
Small Window
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PN
Thick Filter
Small
Window
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ACIS
S3
ACIS
I3
MOS1/
MOS2PN
Flux(0.4-2.5 keV) (e-11 ergs cm^2 s)
2.41
[2.40,2.42]
2.52
[2.51,2.54]
2.10
[2.09,2.11]
2.49
[2.48,2.50]
OVIII Ly-a
(e-3 photons/ cm^2 s)
6.51
[6.14,16.9] 5.26
[4.95,5.70]
5.02 [4.93,5.16]
6.63 [6.60,7.28]
Ne IX triplet
(e-3 photons/
cm^2 s)
3.19
[2.58,3.80]
2.80
[2.48,3.11] 2.60
[2.51,2.69]
2.93
[2.78,3.08]
Comparison of Fitted Results between XMM and ChandraComparison of Fitted Results between XMM and Chandra
Chandra X-Ray Observatory CXC
Paul Plucinsky February 200517
Mkn 421Obsid 4148: row 178Obsid 5332: row 512
12.35 A (1004 eV)15.54 A ( 798 eV)18.71 A ( 662 eV)21.12 A ( 587 eV)23.48 A ( 528 eV)25.09 A ( 494 eV)
Schulz
(MIT)
Chandra X-Ray Observatory CXC
Paul Plucinsky February 200518
Schulz(MIT)1004 eV 662 eV
587 eV 494 eV
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Conclusions and Future WorkConclusions and Future Work
• ACIS BI and FI CCD results are more consistent than earlier, but discrepancies still exist• ACIS results appear to be more consistent with the PN results • We need to fit the rest of the XMM data• We need to understand and constrain the relative contribution of the lines and the continuum• We need to improve the BI spectral redistribution function• We need to understand the apparently “discrepant” data sets for ACIS