Utilizzo degli archivi e informazioni di base per l’analisi dei dati in banda X

1. Utilizzo degli archivi e informazioni di base per l’analisi dei dati in banda X Laboratorio Alte Energie - 2008

2. Una breve introduzione Le regole di base per la riduzione dei dati in banda X sono essenzialmente le stesse nella maggior parte dei casi, ma una buona conoscenza delle proprieta’ dei satelliti e degli strumenti e’ fondamentale per massimizzare l’output scientifico (e.g., lezioni di P. Grandi e M. Dadina). I dati di ogni satellite X sono in genere “accompagnati” da software o tools specifici atti a facilitarne la riduzione e l’analisi scientifica Come ottenere I dati: proposte di osservazioni  dati di proprieta’ (in genere per un anno)  dati in archivio accessibile a tutti  gli archivi rappresentano una componente fondamentale per la ricerca (per esempio, ≈6000 osservazioni nell’archivio Chandra, frutto di 8-9 anni di osservazioni) Laboratorio Alte Energie - 2008

3. Some hints of X-ray data reduction • Chandra data reduction: from evt1 to NEW evt2 following the CXC threads  data reprocessing to adopt the most up-to-date calibrations • Chandra: extraction of the source and background spectra for X-ray spectral fitting  easy task, background generally not so critical • XMM-Newton data reduction: create NEW pn and MOS1+MOS2 event files and check for high-background intervals following the threads available at vilspa  data reprocessing to adopt the most up-to-date calib • Extraction of the spectra  background typically provides a non-negligible contribution (unless the source is very bright)

4. Chandra webpage CXC Science Archive Proposer Calibration Data Analysis Data Centers […]

5. Chandra X-ray Data Center (CXC) http://chandra.harvard.edu/ • Data analysis  CIAO  Science threads • http://cxc.harvard.edu/ciao/threads/index.html • Introduction • Data preparation • Timing analysis • Imaging • Imaging spectroscopy • Grating spectroscopy • […] But … where can we download the data? Laboratorio Alte Energie - 2008

6. Chandra archive: using webchaser Data archive Chandra archive: downloading the data with webchaser  primary files with evt2, images and other stuff  secondary files with evt1, bias, calib. and other stuff Laboratorio Alte Energie - 2008

7. ACIS data preparation: hints • Create a new bad pixel file (acis_run_hotpix) to provide a list of • bad and hot pixels • Create a new EVT2 file for scientific use (acis_process_events) •  apply an ACIS gain map •  apply a time-dependent ACIS gain correction •  apply the ACIS CTI correction •  apply/remove PHA randomization •  clean ACIS background in VFAINT mode • Select the grades and the Good Time Interval (GTI) • Improve the astrometry of the data (also before acis_process_events) • to correct for any known processing offset or to match data with higher • accuracy positions (e.g., from the radio band) • Filtering the data: check for flares in a background-only region (updated • GTI) and select the energy range Laboratorio Alte Energie - 2008

8. evt1 evt2 Laboratorio Alte Energie - 2008

9. Extraction of spectra in Chandra ACIS • From the “clean” evt2 file, create an image in the chosen energy range • and determine the centroid of the X-ray emission for spectra extraction • (for either faint or extended sources, visualize also the smoothed image) • Example: • dmstat "evt2_clean1.fits.gz[sky=region(sou_r2.reg)][bin sky=1] • [cols chipx,chipy,ccd_id,x,y]" centroid=yes • Select the source and background regions using ds9 • Avoid to include nearby sources in the background region • Run psextract to extract the (source+background) spectrum, the backg. • spectrum, the Redistribution Matrix File (RMF) and the Ancillary • Response File (ARF), required for X-ray spectral analysis within XSPEC • or Sherpa • Rebin the data if the number of counts is high enough to apply the 2 • statistics Laboratorio Alte Energie - 2008

10. RMF ARF RMF and ARF RMF: includes information on the detector gain and energy resolution (channel  energy conversion) ARF: includes information on the effective area, filter transmission and any additional energy-dependent efficiencies

11. RMF ARF Laboratorio Alte Energie - 2008

12. unsmoothed Chandra mosaic Laboratorio Alte Energie - 2008

13. “true-color” smoothed Chandra mosaic red=0.5-1.5 keV green=1.5-2.5 keV blue=2.5-8.0 keV Laboratorio Alte Energie - 2008

14. Example of src+bkg and bkg extraction Laboratorio Alte Energie - 2008

15. XMM-Newton webpage News Observers Info Proposers Info Calibration and Background Treatment Data Products Data Analysis […]

16. XMM-Newton Science Operation Center http://xmm.vilspa.esa.es/ • Proposer’s Info and Manuals  Instrument info and • guides (ABC guide: htpp://heasarc.gsfc.nasa.gov/docs/xmm/abc) • Science threads at • http://xmm.esac.esa.int/sas/7.0.0/documentation/threads • SAS start-up: configuration of the working environment and CCF • (Current Calibration Files) • EPIC calibrated and concatenated event lists • RGS: high-resolution spectroscopy • OM: UV photometry • […] … how to retrieve the data to be processed … Laboratorio Alte Energie - 2008

17. XMM-Newton archive: using XSA Data archive XMM-Newton archive: downloading the data using XSA  ODF (Observation Data Files), useful to use the most up-to-date calibrations related to the instruments in the data reprocessing  PPS (Processing Pipeline Files), i.e., already processed data using a standard pipeline Laboratorio Alte Energie - 2008

18. EPIC data preparation: hints • Create a new event file for pn, MOS1, and MOS2 (epproc and emproc) • Create a light curve to check for flares. • Suggestion: select the energy interval E>12 keV • Remove the period of high background level: •  by hand: manually select the new GTI •  using some tasks (e.g., xmmlight_clean.csh, which removes counts • > 3 σ from the mean until a stable solution is obtained) •  using the “Baldi procedure”: CR[10-13 keV]<0.35 cps (pn) & • CR[10-12.4 keV]<0.15 cps (MOS1, MOS2) • Verify that the high-background intervals have been removed • Select the pattern (typically 0-4 for pn and 0-12 for MOS12), the • energy range and the level of cleaning of the data (e.g., flag=0) • Create and display an image and check for the level of the background Laboratorio Alte Energie - 2008

19. Extraction of spectra in XMM-Newton EPIC • From the “clean” event file, create an image in the chosen energy range • and select the source- and background-extraction regions, possibly in • the same CCD chip  visualize the smoothed image in case of faint or • extended X-ray sources and optimize the source extraction radius in • order to maximize the S/N ratio (task eregionalyse) • Run especget to extract the (source+background) spectrum, the backg. • spectrum, the Redistribution Matrix File (RMF) and the Ancillary • Response File (ARF), required for X-ray spectral analysis within XSPEC • Required: source and background regions in physical coordinates • Rebin the data with N>15-20 counts per bin in order to apply the 2 • statistics • Alternatively, use the Cash-statistics on the unbinned data if the number counts is low Laboratorio Alte Energie - 2008

20. An example of XMM-Newton image… EPIC-pn EPIC-MOS

21. …and spectrum Laboratorio Alte Energie - 2008

22. HEASARC webpage Past, present, and future X-ray/-ray missions Archives + Calibrations (CALDB files) Software Tools […]

23. HEASARC archive tool

24. among the other tools… E=h =hc/ energy converter tool 1 keV 12.3984Å h=6.662 10-27 cm2 g/s ; 1 keV=1.602 10-16 joule=1.602 10-9 erg=1.602 10-9 g cm2 /sec2

25. Radio sub-mm Infrarosso ottico UV Banda X Log f IR peak due AGN reprocessed radiation by dust Log  Laboratorio Alte Energie - 2008