The RGS view of Markarian 421 Beatriz Mingo

The RGS view of Markarian 421 Beatriz Mingo Fernandez (bmingo@sciops. esa. int) Tutor: Andy Pollock

Outline Lights The AGN zoo Characterising Markarian 421 Divide and conquer Plot, plot Future prospects Shadows Interstellar Absorption Combine and conquer Walk the line Opening Pandora's box

The AGN zoo

MKN 421's time variability

MKN 421 in the RGS

Divide and Conquer Split the obsids in 1000 second bins Enough counts even for the faintest spectra Cash statistics (poissonian) Generate spectra for each bin SAS version 9. 0 rgsproc -> GTI Fit a simple model to all the spectra Tbabs*powerlaw Fixed and free n. H Log-parabolic model?

Parameters Each spectral fit gives a set of parameters: n. H: Hydrogen column density Alpha: powerlaw index Norm: powerlaw normalisation constant Additional information: Count rate Complete 1 ksec spectra Energy ranges: Time (1) 0. 33 -0. 5 ke. V (2) 0. 5 -0. 85 ke. V (3) 0. 85 -2. 0 ke. V

Alpha vs. count rate

Individual observations

Hardness ratio, RGS 1

Future prospects Different models Include new data Combine and conquer rgscombine Write paper Get rich & famous

ISM absorption T ~ 10^6 K H-like, He-like ions O VII, O VIII, C VI, N VI, edges (Fe-L, O) Individual spectra Only in the brightest spectra, only strongest lines 49 observations of MKN 421, over 1 Msec Why not combine them?

Combine and conquer Take out offset observations Avoid spread of CCD edge features Total: 45 observations, ~1. 3 Msec 1 + 1 > 2: every photon counts Consider effective areas, bad pixels Use standard software, so anybody can repeat and obtain the same results Public data from both RGS 1 and RGS 2 SAS 9. 0 -> rgscombine -> 1 st and 2 nd order spectra XSPEC 12. 5, standard models, C-statistics

O VII 21. 602 Angstrom

O VII 21. 602 Angstrom 21. 605 Angs. eq. width 0. 4017 e. V

O I 23. 50? Angstrom 23. 516 Angs. eq. width 0. 3732 e. V

C VI 33. 74 Angstrom?

O VII beta 18. 63 Angstrom?

Opening Pandora's box Better calibration of the RGS? What if MKN 421 is not a powerlaw? Modelling interstellar edges Improving CCD edges Same procedure can be done on other sources PKS 2155 -304, 3 C 273 Emission sources The elusive WHIMs Filaments of warm-hot gas joining galaxies

THANK YOU! I'll be back!