EPIC cal meeting, Mallorca, 2009 March 31 / April 1

Using line-rich RGS spectra to calibrate the re-distribution of EPIC-pn

Frank Haberl

Sources and spectral models:

Models derived from RGS spectra:SNR 1E0102.2-7219 continuum + emission linesStar Zeta Puppis continuum + emission linesComet C/2000 WM1 emission lines

Other sources for consistency checks:INS RXJ0720.4-3125 bbody + broad absorption lineINS RXJ1856.5-3754 bbody (+bbody?)AGN MS1229.2+6430 powerlawAGN H1426+428 broken powerlaw(AGN PKS2155)(SNR G21.5-09)

1E0102.2-7219Model from the cross-calibration work (Plucinsky et. al 2008, SPIE 7011E, 68)Derived from combined RGS spectra of 23 observations (+EPIC-pn for higher energies) rgspn_mod_tbabs_tbvarabs_2apec_line_ratios_jd_v1.9.xcm

Fit to pn spectra:only constant factor allowed to varygain fit with slope==1.0 and shift as fit parameter

RGS1 708 ksRGS2 680 ks

O VII f 561 eVO VII i 567 eVO VII r 574 eVO VIII Lyα 654 eVO VII Heß 666 eV

1E0102 .2-7219The current response:Problems with energy resolution

andre-distribution of O-lines

FF

SWLW

Zeta PuppisModel similar to that of 1E0102 .2-7219Derived from combined RGS spectra of 13 observations (+EPIC-pn for higher energies)

Fit to pn spectra:only constant factor allowed to varygain fit with slope==1.0 and shift as fit parameter

RGS1 663.6 ksRGS2 668.8 ks

N VI f 420 eVN VI i 426 eVN VI r 431 eVN VII Lyα 500 eV

Zeta Puppis

The current response:Problems with energy resolution

andre-distribution of N-lines(the shoulder is too narrow)

To avoid pile-up and optical loading with EPIC-pn:Use SW mode with thick filter!

Comet C/2000 WM1A pure line spectrum with no continuumThe current response:Unknown spectrum below 300 eV

C VI Lyα 368 eVO VII f 561 eV

1E0102 .2-7219A new response matrix:Adjustment of energy resolution

andre-distribution below ~700 eV

FF oldχ2 = 1495

FF newχ2 = 859

1E0102 .2-7219A new response matrix:Adjustment of energy resolution

andre-distribution below ~700 eV

LW oldχ2 = 1585

LW newχ2 = 1236

1E0102 .2-7219A new response matrix:Adjustment of energy resolution

andre-distribution below ~700 eV

SW oldχ2 = 1668

SW newχ2 = 1112

Zeta PuppisA new response matrix:Adjustment of re-distribution between 400 eV and 700 eV

SW oldχ2 = 1140

SW newχ2 = 814

Chi-squared comparison

41301 28082

gain shift (eV)

-2.06 -5.56 -3.22 2.204.01 1.24 -1.29 2.33 0.56 2.91 0.73 -0.74 1.84 1.55 1.32 -0.06 -3.31 6.43 5.41 5.56 6.40 8.37 4.713.73 2.14 -0.26 2.33 -3.61 0.19

-4.83 -4.73 -1.31 -3.59 -2.61 -9.36 -6.13

MS1229.2+6430Powerlaw fitssingles

FF oldχ2 = 387dof = 329

FF newχ2 = 321

MS1229.2+6430Powerlaw fitssingles+doubles

FF oldχ2 = 473dof = 395

FF newχ2 = 403

H1426+428Broken-powerlaw fitsNH fixed at 1.36·1020 (phabs-wilms)singles+doublesRev. 278: no break

SW oldχ2 = 5027dof = 3313

SW newχ2 = 4666

Allow break for Rev. 278:χ2 = 4302Index 1.87/1.77

RX J1856.5-3754Blackbody fitssinglesNH, kT, norm linkedfree constant

SW oldχ2 = 2114dof = 1403

SW newχ2 = 2770

Summary of current status (Friday, March 27)Improved re-distribution down to ~400 eV (1E0102 .2-7219, Zeta Puppis)Adjusted energy resolution for FF, LW and SW mode

Still inconsistencies below 400 eVPowerlaw spectra somewhat improvedRXJ1856.5-3754 gives considerably worse fit

Use Comet, powerlaw sources and RX1856.5-3754 to fine-tune re-distribution below 400 eV.