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Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop.

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Presentation on theme: "Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop."— Presentation transcript:

1 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 Emission measure distribution from the analysis of coronal data Fabio Reale Dipartimento di Scienze Fisiche & Astronomiche Università di Palermo, Italy

2 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 Summary  DEM of quiescent loops from SoHO/CDS data:  Hot active region loop  Cooler (TRACE) loop: multi-wavelength  DEM of flaring loops from Yohkoh/SXT data

3 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 DEM of quiescent loops  History of DEM saga:  Use spectroscopy to derive thermal structure: DEM reconstruction  Wide DEM indicates multi-thermal fibrils, thin DEM monolithic loops  DEM reconstruction shows single line ratios bias ( Schmelz et al )  Debate on DEM reconstruction ( Schmelz 2002, Martens et al. 2002, Aschwanden 2002, Schmelz et al ): different results, problem of background subtraction Schmelz et al T DEM

4 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 Debate on loop DEM  DEM multiplicity (Schmelz et al. 2005):  Analysis of a loop on the limb (CDS/SoHO)  Multi-thermal structure at three locations: apex, left and right leg  Different from other hot loops looking isothermal ( Di Giorgio et al. 2003, Landi & Landini 2004 )  CDS atlas reveals many examples of both types of loops: different heating mechanisms? Di Giorgio et al Schmelz et al. 2005

5 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 DEM of an active region loop ( Di Giorgio et al )  Analysis of a SoHO/CDS observation of active region loops (14 rasters)

6 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 The CDS data

7 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 Quantitative analysis: strip enclosing the loop

8 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 DEM at the apex sector (raster 4)

9 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 Cooler quiescent loop (Reale & Ciaravella 2005, A&A, submitted)  Rationale:  Investigate how far one can go with present loop observations  TRACE-selected loop  Multi-wavelength observation  Time-resolved observation  Images

10 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 The observation  Morphology (TRACE-based selection):  Whole loop visible: OK (171 A filter)  Bright: OK  Isolated: half  On the disk: OK (+230”, +470”)  Long-lived (> 2 hours), slowly variable  Length: ~10 10 cm  Multi-band observation:  TRACE:  Filters: 171 A, 195 A, 284 A  32x3 frames (1024x1024, 3.5 hours)  Pixel size: 0.5”  SoHO/CDS:  Two relevant rasters (i.e. no time resolution)  11 relevant lines (5.9 < logT <6.4)  Pixel size: 2.5”  Yohkoh/SXT:  Nine 512x512 frames (8 AlMg + 1 Al.1)  Pixel size: 5” L

11 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 The observation  Time coverage (13 May 1998):  TRACE:  6:30-10:00 UT  Yohkoh/SXT:  6:30-8:40 UT  SoHO/CDS:  7:50-8:46 UT (Raster 1)  10:23-12:12 UT (Raster 2) L TRACE SXT CDS 6:30UT12:30UT

12 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 The loop life  TRACE Animations:  Time-interpolated images (~3.5 hours)  Background subtracted (see below)  The loop is slowly variable:  The brightness distribution changes  It fades away

13 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 TRACE: Data processing  Pre-processing: trace_prep,wave2p,unspike,destr,derip,new_avg Cross-correlation (align_cube_correl)  Alignment: for each filter Cross-correlation (align_cube_correl)  Background subtraction:  Since the loop disappears at the end of the sequence, we use the last frame (for each filter) as background  Subtract the last frame from all others

14 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 TRACE: 171 A  Raw images:  Loop:  Some filamentation but globally coherent evolution  best visible after 1 hour  then it fades  Bkg-sub images:  Enhanced loop contrast  Asymmetric evolution:  Right leg first  Left leg later  Slow fading

15 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 Yohkoh/SXT  Data processing:  Sxt_prep,/register,/vignette  Cross-correlation alignment (w/ TRACE 284)  Rebinning: pix=1 arcsec  Background subtraction: same as TRACE (AlMg only: no temperature diagnostics)  Raw images:  Similar to TRACE 284 A  Loop confused inside an arcade?  Bkg-sub images:  The loop shows up  The loop fades  Overlaps TRACE loop

16 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 TRACE vs Yohkoh  The loops overlap quite well SXT

17 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 Filter ratio maps: 195/171  Temperature indicator  Moderate structuring along and across the loop

18 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 The loop analysis  Strip along the loop  Strip divided into sectors

19 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 Light curves  e-folding decay time: ~3000 s  Hotter plasma decays sooner  Thermodynamic loop decay time (Serio et al. 1991): with L 9  4.2 and T 7  0.1

20 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 Filter ratio profiles Del Zanna (http://loopbench.astropa.unipa.it)

21 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 Filter ratio Filter ratio 195/171  Raw Bkg sub. 

22 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 Filter ratio evolution  Two regions:  Apex (upper points)  Whole loop (lower)  The loop cools down

23 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005  CDS Data Set 14 Rasters 07:13:15 12:11:58 UT 1: FOV too small 3-13: Spectral Range too narrow 2: 07:50: :46:02 LOOP 14: 10:23: :11:58 Background  Calibration Phot/cm 2 /sec 1 /arcsec 2 /Å Background Subtraction: no loop in the last raster SoHO/CDS: the data

24 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 BackgroundLoop  Different FOV, Pixels, Spectral lines  Aligned ( align_cube_correl )  Rebinned to TRACE Pixels size

25 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005

26 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005  Most of the loop is visible in Ca X and Mg IX  The whole loop is visible in Mg X and Si X  Just the right end is visible in Si XII, Fe XIV and Fe XVI

27 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005

28 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 CDS lines brightness distributions along the loop

29 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 Emission Measure  G(T) function  Mazzotta et al. (1998) ionization equilibrium fractions

30 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 Results  Hottest: sector 9  Moderate width:  Sharp hot side  Smoother cool side  Sector 2: unclear (overlapping structures)

31 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 TRACE vs CDS  TRACE 171 A image degraded to CDS space resolution & “rasterized”

32 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 DEM of flaring loops from Yohkoh/SXT data  General project: the Sun is our template of X-ray star  For direct comparison with stellar data, we have to translate the solar data into the same passband and format of the stellar data  We need the whole X-ray spectrum of the Sun: not available  Our approach:  Use full-disk space-resolved Yohkoh/SXT data (images in a few wide bands, moderate spectral information)  Derive the EM distribution vs temperature of the whole corona  Derive X-ray spectra  Derive instrument-filtered X-ray spectra  Put spectra at stellar distance

33 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 ~ simultaneous Yohkoh/SXT images through different filters Derive Temperature and emission measure for each pixel TemperatureEmission Measure  From two simultaneous SXT images taken with different filters, derive the temperature and emission measure for each pixel in corona  From the two sets of T and EM values, rearrange and obtain the distribution of emission measure vs. temperature, EM(T): we divide the range of T detectable by the instrument (5.5 < Log T [K] < 8 K) into bins and sum up all the EM values within each “temperature bin” (Orlando et al., 2000; Peres et al., 2000): DEM from Yohkoh/SXT data

34 (Peres, Orlando, Reale, Rosner, Hudson 2000) Whole-Disk EM(T) Distributions

35 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 Flares (Reale, Orlando & Peres 2001)  Selection: from C to X-class

36 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 Flare selection: well-observed

37 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 Flare DEM evolution from SXT data  Be and thick Al filter bands  Flare evolution (time: pale to dark) vs background (quiet/active) corona  Result: well-defined peak, small temperature change, larger EM change

38 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 If we include more filters….  … the DEM becomes flatter on the cool side

39 The X-class flare 2-Nov-92, 13:11, AlMg

40 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 Overall  Small dependence of T on class  X-class: broader and hotter

41 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 Synthesis of flare X-ray spectra

42 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 THE END

43 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 DEM of flaring loops: A different approach  Preface:  The Sun is our star template  The Sun is our corona template  We resolve the Sun vs we don’t resolve stars  Questions:  Can we use the Sun as a “meter” to “measure” stellar coronae?  Can we use the Sun as a guide to study the stellar coronae  Answer:  YES, but we have to translate the solar data into stellar data  Our approach:  Use full-disk space-resolved Yohkoh/SXT data (images in a few wide bands, moderate spectral information)  Derive the EM distribution vs temperature of the whole corona  Derive X-ray spectra  Derive instrument-filtered X-ray spectra  Put spectra at stellar distance

44 From the EM(T) Distr. to the Coronal Spectrum 6-Jan-92 D = 1 pc t_exp = sec … to the X-ray Spectrum of the Sun as a Star Spectral Synthesis (MEKAL) Chandra/ACIS Folding the synthetic spectrum through the instrument response

45 Palermo, 14 Sept., 2004 From the EM(T) Distr. to the Coronal Spectrum Chandra/ACIS 6-Jan-92 D = 1 pc t_exp = 2e5 sec … to the X-ray Spectrum of the Sun as a Star

46 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 TRACE: 195 A  Raw images:  More bright structures  Loop visible since the beginning  Bkg-sub images:  Steadily uniform brightness  Gradual fading

47 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 TRACE: 284 A  Raw images:  Bright T-like structure  Loop is faint  Bkg-sub images:  Loop faint but visible (right leg)  Faster fading

48 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 Yohkoh/SXT  Field of view

49 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 Emission profiles 171 A  Raw Bkg sub  195 A284 A171 A

50 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 Filter ratio HR 195/171  Raw Bkg sub. 

51 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 The hot loop  Let’s focus on the hot loop (Fe XVI): loop A

52 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 Multi-wavelength TRACE-selected loop (Reale & Ciaravella 2005, A&A, submitted)  Selection in: list of SoHO campaigns (http://sohodata.nascom.nasa.gov)http://sohodata.nascom.nasa.gov  Selection made by: F. Reale  SoHO campaign: 5170  Date: 13 May 1998  Name: Active region study  Coordinator: Robert Walsh  Rationale:  Investigate how deep one can go with present loop observations

53 Dipartimento di Scienze Fisiche & Astronomiche – Universita’ di Palermo INAF/Osservatorio Astronomico G.S. Vaiana Fabio Reale RESIK,RHESSI &SPIRIT workshop Wroclaw 6-8 Dec 2005 TRACE: Data processing  Pre-processing: trace_prep,wave2p,unspike,destr,derip,new_avg Cross-correlation (align_cube_correl)  Alignment: for each filter Cross-correlation (align_cube_correl)  Background subtraction:  Since the loop disappears at the end of the sequence, we use the last frame (for each filter) as background  Subtract the last frame from all others  Pros:  In principle, very accurate  No interpolation  Pixel-by-pixel  Analyze all loop pixels  Cons:  Assumes no background evolution (13% variations on average)  Possible variations of crossing structures


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