identification of lines in the range 3. 3 Å - 6.1 Å observed in resik spectra

35th COSPAR: Scientific Commission E1.9; Paris, 18-25 July 2004

Identification of Lines in the Range 3.3 Å - 6.1 Å

Observed in RESIK Spectra

B. Sylwester, J. Sylwester, M. SiarkowskiSpace Research Centre, Polish Academy of Sciences, Wrocław, Poland

K.J.H. Phillips NASA Goddard Space Flight Center, Greenbelt, USA

L. Culhane Mullard Space Science Laboratory, Dorking, Surrey, UK

J. Lang Rutherford Appleton Laboratory, Chilton, Didcot, UK

C. Brown Naval Research Laboratory, Washington DC, USA

V.D. Kuznietsov IZMIRAN, Moscow region, Troitsk, Russia


INTRODUCTION

RESIK is a common project between NRL (USA), MSSL and RAL (UK), IZMIRAN (Russia) and SRC (Poland). It is Bragg bent crystal X-ray spectrometer placed aboard the CORONAS-F satellite. The wavelength coverage of RESIK is 3.3 Å ÷ 6.1 Å (four energy channels). Preliminary analysis of spectra collected indicates presence of many spectral features identified earlier in the flaring plasmas and corresponding to the transitions 1s-2p in H-like ions and 1s2-1s2p in He-like ions of S and Si. In addition many prominent lines not earlier observed can be identified in RESIK spectra. We have calibrated the spectra, establishing an absolute wavelength scale and determining the absolute photon fluxes. This made it possible to identify several spectral features, some of which are observed for the first time from astrophysical plasmas. In particular we have detected lines due to highly ionized potassium and chlorine. Potassium belongs to very low FIP elements (4,31 eV) while chlorine to high ones (12.97 eV).


http://www.cbk.pan.wroc.pl/resik_catalogue.htmhttp://www.cbk.pan.wroc.pl/legend/legend_2003.htm

http://www.cbk.pan.wroc.pl/resik_catalogue.htm


Example spectra

As an example of RESIK observations in the two successive slides, we present the spectra recorded for a moderate disk (N16W05) flare of C5.8 class. It was a short duration event observed over its entire duration.

The spectrum filled in GREEN is the original one (counts vs bin numbers) while in BLUE corresponds to the absolute calibration (photons vs Å).

The individual channels are presented in different blue semi-tones: 3.35 - 3.8 - 4.3 - 4.9 -6.0 Å.


RESIK background corrected spectrum (C5.8 flare on 22 Feb.2003)

Spectrum integrated over the event duration (584 s). Red arrows indicate for Cl H- and He-like line positions. Red ? indicate for unidentified lines.

K XVIII

S XVI

Ar XVII

S XV-3pS XV-4p

S XV

Si XIII-3pCl

Cl

?

?

??Ar XVI

Ar XVII 3p


Reduced RESIK spectrum for (entire) flare on 22 Feb. 2003

The spectrum has been integrated over the flare duration – 584 sec.

The individual channels are presented in different blue semi-tones.

K XVIII

Ar XVII

S XV-4p

S XV-3p

S XVI-2p

S XV-2p

Si XIII-3p

Cl XVII (Lyα)

Cl XVI (R,I,F)

Si XIIISi XIV Si XII

Ar XVIII


Distribution of activity during 1 January – 14 March 2003

We have analysed here the RESIK spectra collected between 1 January and 14 March 2003. During this period 1163 time intervals have been chosen for which the spectra have been measured. The collected set of spectra covers as well very low activity level (~B4) as few M class flares. No single X class flare has been reported during analysed period.


Data analysis

Using the ratio of total (lines+continuum) fluxes measured in the most energetically separated RESIK channels (#1 and #4) in the regions (3.4 -3.8 Å) and (5.0 – 6.05 Å) respectively we have calculated the temperature and emission measure (in an isothermal approximation) for all analysed cases. This in turn allowed us to calculate the expected continuum level and subtract it from the observed spectrum in order to better see the lines.


RESIK average spectrum for 1 January – 14 March 2003 period

SGI = 388.6 hours(1163 cases added)


The same in logarithmic scale


Average spectra grouped according to the temperature

K XVIII 2p Ar XVIII 2p (Lyα)

S XV 4p

S XIV sat

We averaged the observed spectra in individual groups characterised by different temperatures.


Average spectra grouped according to the temperature

S XIV satS XV 3p

Si XIV 3p Lyβ

Si XIII 3p

Si XIII sat

Poster P 0108


Channel 1 and 2 averaged RESIK spectra

Ar XVII 3p

Ar XVI sat

K XVIIIw,x,y,z

S XVI 6p

Ar XVIII 2p

S XVI 4p

Ar XVIIw,x,y,z

S XV 4p

S XV 3p

S XVI 5p

S XIV sat

S XIV sat

? ? ?

Poster 0112


Channel 3 and 4 averaged RESIK spectra

S XIV sat

S XV 3p

Cl XVIw,x,y,z

S XVI 2p

S XVw,x,y,z

Si XIV 3p

Si XIII 4p

Si XIII 5p

Si XII sat

Si XIII 3p

Si XII sat

Si XIV 6p

Si XIV 5pSi XIV

8p

Al XIII 5p

Al XIII 4p

Al XIII 3p

??


What can be done with RESIK unique observations

Determination of chemical composition of X-ray flare and active region plasma with a high precision using emission line and continuum intensities (K, Ar, Cl, S, Si, Al). FIP dependence analysis of absolute coronal abundances:

FIP (eV): 4.31 5.99 8.15 10.36 11.97 15.76 element: K Al Si S Cl Ar

Differential emission measure analysis (DEM)-determination of the temperature structure of emitting regions.

The RESIK range includes many strong emission lines due to transitions 1s-np and 1s2-1snp in H-like and He-like ions respectively. The lines corresponding to the transitions for n = 2 and 3 are routinely observed for Si, S and Ar ions. For some flares we observe the enhanced emission in spectral features coinciding with these transitions for n up to 9 or 10. (The analysis of observed line series decrements.)

identification of lines in the range 3. 3 Å - 6.1 Å observed in resik spectra

Documents

preduced resik spectrum

flare duration

resik spectrab

separated resik channels

wavelength coverage

collected set of spectra

entire flare

example of resik observations