a comparison of spectral fit results of e0102 from the chandra … · 2009-01-22 · chandra x-ray...

Chandra X-Ray Observatory CXC

Paul Plucinsky February 20051

A Comparison of Spectral Fit ResultsA Comparison of Spectral Fit Resultsof E0102 from the Chandra andof E0102 from the Chandra and

XMM XMM CCDsCCDs

Paul Paul Plucinsky Plucinsky && Joseph Joseph DePasqualeDePasquale



Other Contributors to this Effort Other Contributors to this Effort

CXC: R. Edgar , N. Schulz, A. Vikhilin

MIT: K. Flanagan, D. Dewey, lots of help from MIT ACIS team



Why Use E0102 as a Calibration Source for the Why Use E0102 as a Calibration Source for the CCDsCCDs??

• Well-characterized spectrum, both the Chandra HETG andXMM RGS have observed the object• The spectrum is relatively simple by astrophysical standards, noor 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-boardcalibration source does not have strong lines• Low-energy part of the bandpass is always a challenge to calibrate



Spectral Model: Calibration Spectral Model: Calibration vsvs. Astrophysics. Astrophysics

• Primary Objectives are to measure the gain, the spectralredistribution function, and detection efficiency in the 0.5 -2.0 keVrange• Our immediate concern is to develop a model useful forcalibration, not to develop an astrophysically-meaningful model,• We use a model consisting of 24 Gaussians for the lines identifiedby the HETG and RGS, a bremsstrahlung for the continuum, and atwo component absorption (Galactic and SMC)• Line energies are fixed at the true values and the widths of theGaussians are fixed at zero, so the only parameter which varies isthe 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 (654eV) to 0.1368 (ratios from Flanagan et al. 2004)



ACIS-Specific ACIS-Specific CalibrationCalibration Issues: 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 thecontamination (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 eachMOS1/MOS2/PN)

Chandra Data:Chandra Data:• 44 observations on I3 and 20 observations on S3, roughly onceevery 6 months• Data (spectra, rmfs, & arfs) available at:“http:cxc.harvard.edu/acis/E0102/splash.html” Available for anyone to download, please do if you would like the data !!



Gratuitous Pretty Pictures of E0102Gratuitous Pretty Pictures of E0102

S3 Summed Data ~100 S3 Summed Data ~100 ksks True Color ImageTrue Color Image



S3(BI)



OVII triplet

OVIII Ly-aNe IX triplet

Ne X Ly-a

Mg XI triplet

S3(BI)



OVIItriplet

OVIII Ly-a

Ne IXtriplet Ne X Ly-a

Mg XI Ly-a

I3(FI)



MOS 1

MOS 2

Thick filter

Large Window



MOS 1

MOS 2

Thick Filter

Large Window



PN

MOS 1

MOS 2

Thick Filter

Small Window



PN

ThickFilter

Small

Window



2.93[2.78,3.08]

2.60[2.51,2.69]

2.80[2.48,3.11]

3.19[2.58,3.80]

Ne IX triplet(e-3 photons/cm^2 s)

6.63[6.60,7.28]

5.02[4.93,5.16]

5.26[4.95,5.70]

6.51[6.14,16.9]

OVIII Ly-a(e-3 photons/cm^2 s)

2.49[2.48,2.50]

2.10[2.09,2.11]

2.52[2.51,2.54]

2.41[2.40,2.42]

Flux(0.4-2.5keV) (e-11ergs cm^2 s)

PNMOS1/MOS2

ACIS I3

ACIS S3

Comparison of Fitted Results between XMM and ChandraComparison of Fitted Results between XMM and Chandra



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)



Schulz(MIT)1004 eV 662 eV

587 eV 494 eV



Conclusions and Future WorkConclusions and Future Work

• ACIS BI and FI CCD results are more consistent than earlier, butdiscrepancies 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 ofthe lines and the continuum• We need to improve the BI spectral redistribution function• We need to understand the apparently “discrepant” data sets forACIS

a comparison of spectral fit results of e0102 from the chandra … · 2009-01-22 · chandra x-ray...

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