1. The RGS view of Markarian 421 Lights Shadows And
Beatriz Mingo Fernandez
Tutor: Andy Pollock

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

3. The AGN zoo

4. MKN421's time variability

5. MKN 421 in the RGS

6. 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 nH
Log-parabolic model?

7. Parameters Each spectral fit gives a set of parameters:
nH: Hydrogen column density
Alpha: powerlaw index
Norm: powerlaw normalisation constant
Additional information:
Count rate
Complete 1ksec spectra
Energy ranges:
(1) keV
(2) keV
(3) keV
Time

8. Alpha vs. count rate

9. Individual observations

10. Hardness ratio, RGS1

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

12. ISM absorption T ~ 10^6 K Individual spectra
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 MKN421, over 1 Msec
Why not combine them?

13. 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 RGS1 and RGS2
SAS 9.0 -> rgscombine -> 1st and 2nd order spectra
XSPEC 12.5, standard models, C-statistics

14. O VII Angstrom

15. O VII Angstrom
Angs.
eq. width eV

16. O I 23.50? Angstrom
Angs.
eq. width eV

17. C VI Angstrom?

18. O VII beta Angstrom?

19. Opening Pandora's box Better calibration of the RGS?
What if MKN421 is not a powerlaw?
Modelling interstellar edges
Improving CCD edges
Same procedure can be done on other sources
PKS , 3C273
Emission sources
The elusive WHIMs
Filaments of warm-hot gas joining galaxies

20. THANK YOU!
I'll be back!