AO ....... Announcement of Opportunity ADF ...... Astrophysical Data Facility ASCA ..... Advanced Satellite for Cosmology and Astrophysics ARF ...... Ancillary Response File CCD ...... Charged Coupled Device COR ...... Cut-Off Rigidity CPU ...... Central Processing Unit CTE ...... Charge Transfer Efficiency CTI ...... Charge Transfer Inefficiency DFE ...... Dark Frame Error FITS ..... Flexible Image Transport System FOV ...... Field of View FWHM ..... Full Width at Half Maximum FRF ...... First Reduction File FTP ...... File Transfer Protocol GIS ...... Gas Imaging Spectrometer GOF ...... Guest Observer Facility GTI ...... Good Time Interval HEASARC .. High Energy Astrophysics Science Archive Research Center HK ....... Housekeeping HTML ..... Hyper-Text Mark-up language HTTP ..... Hyper-Text Transfer Protocol ISAS ..... Institute of Space and Astronautical Science LHEA ..... Laboratory for High Energy Astrophysics mkf ...... mkfilter file MPC ...... Multi Pulse Count OGIP ..... Office of Guest Investigator Programs PHA ...... Pulse Height Analyzer PI ....... Pulse Invariant PSF ...... Point Spread Function PV ....... Performance Verification QDP ...... Quick and Dandy Plotter (previously Quick and Dirty Plotter) RDD ...... Residual Dark Distribution RMF ...... Redistribution Matrix File RTI ...... Rise Time Invariance SAA ...... South Atlantic Anomaly SCC ...... Space Craft Clock SIS ...... Solid-state Imaging Spectrometer TAI ...... International Atomic Time TDB ...... Barycentric Dynamical Time URL ...... Uniform Resource Locator UT ....... Universal Time UTC ...... Coordinated Universal Time WWW ...... World Wide Web XRT ...... X-ray Telescope
The following are major software packages commonly used to analyse data once it has been reduced.
to obtain the User's Guide.
Note the a User's Guide for XSELECT, the package used to reduce the data, can be obtained by consulting the URL
Chapters 5 to 7 on screening and filtering contain extensively annotated ascascreen and XSELECT sessions. Here, however, only sets of command sequences are given, the aim being to provide compact reference points and aides de memoire. In subsequent sections, the following command sequences will be described.
In the following examples, it is assumed that the events files reside in the directory above the working directory and that the mkf file is in same directory. Since ASCA is the default mission, the set mission asca command has been omitted. The screening criteria used in the examples are not unique and the user should use criteria appropriate for each case and should therefore consult chapters 5 and 6 for more details. We omit SIS FAST mode here, as it is somewhat specialized and does not constitute mainstream ASCA analysis (but full details are given in §4.10).
All the subsequent examples read in data into XSELECT by means of the so-called obscat. However, it is possible to read in several events files directly and in such a case the appropriate commands in the examples should be replaced as described here.
First make an ascii list of all the events files you want to read into XSELECT. For example
ls -1 *s0*.unf > s0.list
At this stage be VERY CAREFUL that you keep SIS FAINT, BRIGHT and BRIGHT2 files in separate places, or else edit them out of the list file. You may duplicate the data. You may also need to select the file list on bit rate.
Then read the files within XSELECT by
read events "@s0.list"
This example is based on GIS2.
set datadir .. set instrument gis2 set datamode ph make obscat show obscat choose 1-** select mkf SAA==0&&ELV>5&&COR>6&&ANG_DIST>0.0&&ANG_DIST<0.01&&G2_L1>0.0 filter region a1060_g2_randc.reg gisclean extract events save events a1060_g2.evt
Please note that, by not selecting on bit rate, all bit rates are included. To use, say, HIGH bit rate data only, insert the command select obscat bit_rate.eq.'HIGH' after making the obscat. The file a1060_g2_randc.reg contains the lines:
and corresponds to the high background ring and calibration source in GIS2 (see §5.5.2 for GIS3).
This example assumes SIS0 4-CCD mode BRIGHT mode data. The Sn_PIXLm criteria depend on CCD mode (see chapters 5 and 6). Analysis of BRIGHT2 mode data is identical except for the set datamode command.
set instru sis0 set datadir .. set datamode bright make obscat select obscat bit_rate.ne.'LOW' show obscat choose 1-** select mkf SAA==0&&BR_EARTH>20 &&ELV>10 &&COR>6 &&ANG_DIST>0.0&&ANG_DIST<0.01 && s0_pixl0 > 0 &&s0_pixl0 < 50 && s0_pixl1 > 0 &&s0_pixl1 < 50 && s0_pixl2 > 0 &&s0_pixl2 < 50 && s0_pixl3 > 0 &&s0_pixl3 < 50 &&(T_DY_NT<0||T_DY_NT>4)&&(T_SAA<0||T_SAA>4) sisclean select events grade.ne.1.and.grade.lt.5 extract events save events a1060_s0.evt
Please note that default settings are used with the sisclean command and are entered with a carriage return.
Here, the assumed starting point is a single, already-screened events list (a1060_g2.evt, in this example). Note that the instrument and data mode do not have to be set because XSELECT reads them from the header of the events list. An image is extracted first to enable a region filter (cf_g2.reg, in this example) to be defined. For more details see §7.3 and §7.5.
set mkfdir .. set datadir . read events a1060_g2.evt extract image plot image
In SAOimage, use the Scale, Pan and Color buttons to adjust the appearance of the plot. Then hit the Cursor button. Choose a circular region (a circular region is recommended for greatest accuracy). Move the circle so that its center coincides with the source centroid with the left mouse button, and adjust its size with the middle button. Type s at the keyboard to save the region. Hit the region button and then the write button. Name the file (cf_g2.reg, in this example) and hit return. After hitting the reset button we repeat this procedure to define a background region file (back_g2.reg here). The background region does not have to be circular, and is likely not to be for the SIS. Finally, hit the etc button and then quit. Note that `exclusion' regions can be created in SAOimage by typing e instead of s.
Continuing the XSELECT commands:
filter region cf_g2.reg extract spectrum save spectrum cf_g2.pi yes clear region filter region back_g2.reg extract spectrum save spectrum back_g2.pi no
The yes and no which appear in the command sequence are answers to the the question `Group or rebin the spectra before outputting?' The GIS spectra will be grouped but the SIS spectra will be rebinned. In the case of GIS source spectra, the answer should be yes; for GIS background, no. For the SIS the answers for both source and background spectra will be yes in most cases. See §8.1 and §8.3 for more details.
For the GIS the latest response matrices, or RMF files, are obtained from the CALDB (e.g. by anonymous FTP to legacy.gsfc.nasa.gov). Look in the directory /caldb/data/asca/gis/cpf/ for a sub-directory with a name corresponding to the latest date. As of March 1997, the latest matrices are obtained from
and are called (gis2v4_0.rmf) and (gis3v4_0.rmf) for GIS2 and GIS3 respectively.
For ASCA data taken in the PV phase or early AO-1, ready-made
SIS response matrices can be obtained by
anonymous FTP to legacy.gsfc.nasa.gov from the directory
There are many rmf files in this directory but deciphering the name of just one of them is sufficient to understand what all the rest correspond to. One of the SIS0, chip 1 files is called
The `s0c1' clearly means SIS0, chip 1; g0234 means that the ASCA data must have SIS grades 0,2,3,4 selected; p40 means the so-called `split-threshold' is 40 ADU (this is the case for almost all observations); 512 means that the RMF file has 512 output energy bins; v0.8 means that the matrix was created with program sisrmg, version 0.8, and finally the i means that the spectral files must have PI bins (matrices with h instead of i are appropriate for PHA spectra).
Late into the AO-1 phase, the time-dependence of various aspects of the SIS instrument responses became too large to neglect. In general, the safest option is to generate your own response matrices for all your data, using the FTOOL sisrmg. The `standard' matrices can still be used `Quick-Look Analyses'. If the spectral files were created by XSELECT, sisrmg can obtain almost all of its inputs directly from the spectral files.
To generate the ARF, run the FTOOL ascaarf, giving as input the names of the spectral file and the RMF. The program ascaarf asks for the name of the RMF file for the sole purpose of setting the energy-bin array, although this is optional. The program sisrmg also asks for the name of the ARF file. The way to get around this apparent contradiction (apart from ignoring the question) is to run ascaarf with one of the `standard' SIS response matrices (see §11.3.6 above). See §8.7, 10.6 and 10.7.1 for more details on ascaarf.
As described in §9.4, XRONOS can read in events lists and use them as light curves. In this example, we assume that the starting point is an already-screened GIS PH-mode events list (gx301_g2.evt) which the user wants to filter by region and energy.
set mkfdir .. set datadir . read events gx301_g2.evt extract image
Now make a source-extraction region file as described in §11.3.4, and then
filter region source_g2.reg filter pha_cut 68 170 extract events save events source_g2_soft.evt
The channel range 68-170 corresponds, in GIS PH mode, to keV. See §7.9 for channel-to-energy conversion formulae.
FITS rate files, described in §9.4, can be read into XRONOS. The required steps are identical to those in §11.3.2 or §11.3.3 except for the following.
In this example, the starting point is an already-screened events list. Apart from setting the energy filters, the only `extra' command is set image sky, which changes the columns for which the image is extracted from DETX/DETY (detector coordinates - the default) to X/Y (RA and DEC).
set mkfdir .. set datadir . read events kepler_g2.evt set image sky filter pha_cut 68 170 extract image save image kepler_g2_soft.img clear pha_cut filter pha_cut 509 849 extract image save image kepler_g2_hard.img
The channel ranges 68-170 and 509-849 correspond, in GIS PH mode, to 0.8-2 keV and 6-10 keV, respectively.
Here we list, for reference, all the parameters in the mkf files.
TIME Seconds from Jan. 1, 1993 START Start time of record (e.g., 961005222917177) BN_WIDTH Data Bin Width ETI Extended TI counter
BIT_RATE DP Bit Rate 0:H, 1:M, 2:L ACS ACS Status 0:fine mode, 1:corse mode NSAS NSAS cone angle (sun angle) (deg) (<0 during satellite night) Z_ALPHA R.A.(2000) of Z-Axis (deg) Z_DELTA Dec.(2000) of Z-Axis (deg) EULER_3 3rd Euler Angle (Z-Y-Z) SAT_ALT Satellite altitude (km) SAT_LON Satellite longitude (deg) SAT_LAT Satellite lattitude (deg) ELV Target elevation from the Earth egde (deg) COR Cut Off Rigidity (GeV/c) FOV Field of Veiw 0:Sky/1:Night Earth/2:Day Earth BR_EARTH Angular distance from Bright Earth (deg) SAA In South Athrantic Anormaly? 1:yes/0:no T_SAA Time after SAA passage (s) SUNSHINE 1:satellite is in daytime/ 0:night T_DY_NT Time after day/night transition (s) ANG_DIST Angular Distance of FOV from specified direction (deg)
Note n=0, 1 for SIS0 and SIS1 respectively, and m is the chip identification number.
Sn_MODE SIS_n observation mode 0:Fnt/1:Brt/2:Fst/3:Frm Sn_ID SIS_n CCD ID LIST (e.g., 1111) Sn_DSCR SIS_n Discriminator status SIS_ADRS SIS Address Dscri 0:in 1:out for each chip Sn_GRADE SIS_n grade discriminate value (e.g., 127) Sn_EVTRm SIS_n Chip_m Event Threshold Sn_SPTRm SIS_n Chip_m Split Threshold Sn_AE SIS_n AE Status 0:normal/1:A-off/2:Power off Sn_TEMP SIS_n CCD temperature (deg C) Sn_EVNTm SIS_n chip_m HK Event number (counts/s) Sn_PIXLm SIS_n chip_m HK Pixel number over the threshold (couts/s) Sn_TELMm SIS_n chip_m telemely event number (couts/s) Sn_SATFm SIS_n chip_m saturation flag 0:no/ 1:yes Sn_DFEm SIS_n chip_m dark frame error (ADU)
Note n=2,3 means GIS2 and GIS3 respectively.
GIS_MODE GIS observation mode, 0:PH/ 1:MPC/ 2:PCAL GHVn_L GIS HVLn status 16:off/ 8:reduction/ 0-7:level GHVn_H GIS HVHn status 16:off/ 8:reduction/ 0-7:level Gn_LDHIT GIS_n Lower Discri Hit counting rate (counts/s) Gn_H0 GIS_n HK monitor H0 (counts/s) Gn_H1 GIS_n HK monitor H1 (counts/s) Gn_H2 GIS_n HK monitor H2 (counts/s) Gn_L0 GIS_n HK monitor L0 (counts/s) Gn_L1 GIS_n HK monitor L1 (counts/s) Gn_L2 GIS_n HK monitor L2 (counts/s) Gn_CPU_I GIS_n HK monitor CPU_IN (counts/s) Gn_CPU_O GIS_n HK monitor CPU_OUT (counts/s) Gn_TELM GIS_n telemely event number (counts/s) Gn_CPU_S GIS_n CPU status, run +4, stop +2, error +1 GIS_HAMM GIS Hamming Error 0:off/1:on Gn_TEMP GIS_n temperature (deg C) Gn_HVHMN GISn HV-H monitor (V) Gn_HVLMN GISn HV-L monitor (V) Gn_HVHCM GISn HV-H current monitor (uA) Gn_DEADT GIS_n Dead time correction factor (0-1)
RBM_TEMP RBM temperature (deg C) GIS_RBMF RBM flag status of GIS 0:off/1:on SIS_RBMF RBM flag status of SIS 0:off/1:on RBM_CONT RBM counting rate (counts/s)
Here we list some important URLs mentioned in this document. They are listed in the alphabetical order of their `alias' names.