AIPS/UVPROC2を用いたデータ処理の手引き

STEP 5: イメージングとその表示


STEP 3までで、UVPROC2を使ったvisibilityデータのキャリブレーション (1次処理)完了し、さらにSTEP 4では、additionalな データの編集を行いました。

STEP 5はいよいよimagingです。 IMAGRというtaskを使用してcalibration済みvisibilityデータをFourier変換し、 何はともあれ、どんな画像になるのか見てみましょう。 最終的には、synthesized beam patternをdeconvolutionして画像を「綺麗」に する処理も必要になりますが(CLEAN)、これは次のステップで行うことにして、 ここでは、deconvolutionする前の状態のマップ(dirty mapなどということも あります)を得る手順と、得られたdirty mapの表示方法を説明します。

具体的な手順(使用するAIPSのtask)としては、次のようになります。

  1. イメージング:IMAGR
  2. スペクトラムの表示:ISPEC
  3. 画像データの統計値:IMEAN
  4. 等高線マップの作成:KNTR

等高線マップをつくる際、しばしば、画像に目的天体や視野中心などを 示す+印を打ちたいと思うことがあります。また、広がった 天体の観測では、視野の大きさを示す円を書きたいと感じることも あるでしょう。そのような場合は、KNTRを走らせる前に、 STARSというtaskも使います。


1. イメージング

実行例

>pcat
...
AIPS 1:    6    1 D1OBJ_BC    .UVDATA.    1 UV 28-AUG-2003 02:33:11     
AIPS 1:    7    1 D1OBJ_BC    .CLP3  .    1 UV 28-AUG-2003 02:34:27  
←clip済みcalibration済みvisibilityデータ
>task 'imagr'
>getn 7
AIPS 1: Got(1)   disk= 1  user=   1   type=UV   D1OBJ_BC.CLP3.1        
>imh
AIPS 1: Image=D1OBJ_BC  (UV)         Filename=D1OBJ_BC    .CLP3  .   1  
AIPS 1: Telescope=                                                      
AIPS 1: Observer=Kohno               User #=    1                       
AIPS 1: Observ. date=15-APR-2001     Map date=28-AUG-2003               
AIPS 1: # visibilities     25860     Sort order  TB                     
AIPS 1: Rand axes: UU-L  VV-L  WW-L  BASELINE  TIME1                    
AIPS 1: ----------------------------------------------------------------
AIPS 1: Type    Pixels   Coord value     at Pixel     Coord incr   Rotat
AIPS 1: COMPLEX      3   0.0000000e+00       1.00  1.0000000e+00    0.00
AIPS 1: STOKES       1  -1.0000000e+00       1.00 -1.0000000e+00    0.00
AIPS 1: FREQ       128   8.8408000e+10       1.00  8.0000000e+06    0.00
AIPS 1: RA           1    02 38 07.980       1.00       3600.000    0.00
AIPS 1: DEC          1    59 23 24.900       1.00       3600.000    0.00
AIPS 1: ----------------------------------------------------------------
AIPS 1: Coordinate equinox 1950.00                                      
AIPS 1: UV weight normalization factor  1.3563e-19                      
AIPS 1: Maximum version number of extension files of type HI is   1     
AIPS 1: Maximum version number of extension files of type PL is   3     
>
>   
>inp
AIPS 1: IMAGR: Wide field imaging/Clean task                            
AIPS 1: Adverbs         Values            Comments                      
AIPS 1: ----------------------------------------------------------------
AIPS 1: INNAME     'D1OBJ_BC    '          Input UV data (name)         
AIPS 1: INCLASS    'CLP3  '                Input UV data (class)        
AIPS 1: INSEQ         1                    Input UV data (seq. #)       
AIPS 1: INDISK        0                    Input UV data disk drive #   
AIPS 1: SOURCES    *all ' '                Source name                  
AIPS 1: QUAL         -1                    Calibrator qualifier -1=>all 
AIPS 1: CALCODE    '    '                  Calibrator code '    '=>all  
AIPS 1: TIMERANG   *all 0                  Time range to use            
AIPS 1: SELBAND      -1                    Bandwidth to select (kHz)    
AIPS 1: SELFREQ      -1                    Frequency to select (MHz)    
AIPS 1: FREQID       -1                    Freq. ID to select.          
AIPS 1: SUBARRAY      0                    Sub-array, 0=>all            
AIPS 1: DOCALIB      -1                    If >0 calibrate data         
AIPS 1: GAINUSE       0                    CL (or SN) table to apply    
AIPS 1: DOPOL        -1                    If >0.5 correct polarization.
AIPS 1: BLVER        -1                    BL table to apply.           
AIPS 1: FLAGVER       0                    Flag table version           
AIPS 1: DOBAND       -1                    If >0.5 apply bandpass cal.  
AIPS 1:                                    Method used depends on value 
AIPS 1:                                    of DOBAND (see HELP file).   
AIPS 1: BPVER        -1                    Bandpass table version       
AIPS 1: SMOOTH     *all 0                  Smoothing function. See      
AIPS 1:                                    HELP SMOOTH for details.     
AIPS 1: STOKES     '    '                  Stokes parameters (see HELP) 
AIPS 1: BCHAN         0                    Low freq. channel 0 for cont.
AIPS 1: ECHAN         0                    Highest freq channel         
AIPS 1: CHANNEL       0                    Restart channel number       
AIPS 1: NPOINTS       1                    Number of chan. to average.  
AIPS 1: CHINC         1                    Channel incr. between maps.  
AIPS 1: BIF           0                    First IF in average.         
AIPS 1: EIF           0                    Last IF in average.          
AIPS 1: OUTNAME    '            '          Output image name (name)     
AIPS 1: OUTDISK       1                    Output image disk drive #    
AIPS 1: OUTSEQ        0                    Output seq. no.              
AIPS 1: OUTVER        0                    CC ver. no (Continuum only)  
AIPS 1:                                    *** SET OUTVER ON RESTARTS   
AIPS 1: IN2NAME    '            '          UV work file name            
AIPS 1: IN2CLASS   '      '                UV work file class           
AIPS 1: IN2SEQ        0                    UV work file seq             
AIPS 1: IN2DISK       0                    UV work file disk            
AIPS 1: CELLSIZE      0           0        (X,Y) size of grid in asec   
AIPS 1: ******  VALUE =  0.0000e+00 BELOW LIMIT  1.0000e-12             
AIPS 1: IMSIZE        0           0        Minimum image size           
AIPS 1: NFIELD        1                    Number of fields (max. 64)   
AIPS 1: DO3DIMAG     -1                    > 0 => use different tangent 
AIPS 1:                                    points for each field        
AIPS 1: FLDSIZE    *all 0                  Size of each field.          
AIPS 1: RASHIFT    *all 0                  RA shift per field (asec)    
AIPS 1: DECSHIFT   *all 0                  DEC shift per field (asec)   
AIPS 1: UVTAPER       0           0        (U,V) Gaussian taper         
AIPS 1:                                      units are kilo-lambda      
AIPS 1: UVRANGE       0           0        Min & max baseline (klambda) 
AIPS 1: GUARD         0           0        x,y guard band fractional    
AIPS 1:                                    radius                       
AIPS 1: ROTATE        0                    Rotate image CCW from N by   
AIPS 1:                                    ROTATE degrees               
AIPS 1: ZEROSP     *all 0                  0-spacing fluxes and weights 
AIPS 1:                                    SEE HELP!!                   
AIPS 1: UVWTFN     '  '                    UV dist. weight function     
AIPS 1:                                      blank => uniform           
AIPS 1: UVSIZE        0           0        Array size for doing uniform 
AIPS 1:                                    weights.  0 -> actual field  
AIPS 1:                                    size.                        
AIPS 1: ROBUST        0                    Robustness power: -5 -> pure 
AIPS 1:                                    uniform weights, 5 => natural
AIPS 1: UVBOX         0                    Additional rows and columns  
AIPS 1:                                    used in weighting.           
AIPS 1: UVBXFN        1                    Box function type when UVBOX 
AIPS 1:                                    > 0.  0 -> 1 round pill box. 
AIPS 1: XTYPE         5                    Conv. function type in x     
AIPS 1:                                      default spheroidal         
AIPS 1: YTYPE         5                    Conv. function type in y     
AIPS 1:                                      default spheroidal         
AIPS 1: XPARM      *all 0                  Conv. function parms for x   
AIPS 1: YPARM      *all 0                  Conv. function parms for y   
AIPS 1: NITER         0                    Maximum # of Clean components
AIPS 1: BCOMP      *all 0                  Begin at BCOMP component     
AIPS 1:                                    Specify for each field.      
AIPS 1: NBOXES        0                    Number of boxes for Clean    
AIPS 1:                                    NB: field 1 only.            
AIPS 1: CLBOX      *all 0                  Four coordinates for each box
AIPS 1: BOXFILE    *all ' '                Input file of field params   
AIPS 1:                                    and Clean boxes; ' ' => use  
AIPS 1:                                    FLDSIZE, RASHIFT, DECSHIFT,  
AIPS 1:                                    NBOXES, CLBOX only.          
AIPS 1: OBOXFILE   *all ' '                Output file for final Clean  
AIPS 1:                                    boxes                        
AIPS 1: GAIN          0.1                  Clean loop gain              
AIPS 1: FLUX          0                    Minimum Clean component (Jy) 
AIPS 1: MINPATCH     51                    Min. BEAM half-width in AP.  
AIPS 1: BMAJ          0                    FWHM(asec) major axis Clean  
AIPS 1:                                    restoring beam.              
AIPS 1: BMIN          0                    FWHM(asec) minor axis Clean  
AIPS 1:                                    restoring beam.              
AIPS 1: BPA           0                    Clean beam position angle    
AIPS 1: OVERLAP       0                    1 => restore components to   
AIPS 1:                                    overlapped fields, 2=> expect
AIPS 1:                                    overlaps while Cleaning      
AIPS 1: PHAT          0                    Prussian hat height.         
AIPS 1: FACTOR        0                    Speedup factor see HELP      
AIPS 1: CMETHOD    '    '                  Modeling method:             
AIPS 1:                                    'DFT','GRID','    '          
AIPS 1: CPARM      *all 0                  Task enrichment parameters   
AIPS 1:                                    (1) Antenna diameter (m)     
AIPS 1:                                    (2) Source Spectral index    
AIPS 1:                                    (3) Frequency scaling factor 
AIPS 1:                                    (4) >0 => do DFT imaging     
AIPS 1:                                        (not allowed for now)    
AIPS 1:                                    (5) >0 => scale residuals    
AIPS 1:                                    (6) Half-width in x of box   
AIPS 1:                                    (7) Half-width in y of box   
AIPS 1:                                    (10) multiplier of image size
AIPS 1:                                    to get beam size: 0 => 2;    
AIPS 1:                                    2, 1, 0.5 0.25 supported     
AIPS 1: MAXPIXEL      0                    Maximum pixels searched in   
AIPS 1:                                    each major cycle.            
AIPS 1: DOTV         -1                    Display residuals on TV ?    
AIPS 1:                                    Start with field = DOTV      
AIPS 1: BADDISK    *all 0                  Disks to avoid for scratch.  
> 
>cellsize 0.5 1 pixcel = 0.5"に設定
>imsize 256 画像サイズを256x256 pixに設定
>uvwtfn 'na'
>bchan 1   channel 1から
>echan 128   channel 128まで
>npoints 1  幅1 channelでaverage
>chinc 1   stepも1 channelでchannel mapを作る
>outn 'd1-n1c1'  出力する画像ファイルの名称
>inp
AIPS 1: IMAGR: Wide field imaging/Clean task                            
AIPS 1: Adverbs         Values            Comments                      
AIPS 1: ----------------------------------------------------------------
AIPS 1: INNAME     'D1OBJ_BC    '          Input UV data (name)         
AIPS 1: INCLASS    'CLP3  '                Input UV data (class)        
AIPS 1: INSEQ         1                    Input UV data (seq. #)       
AIPS 1: INDISK        0                    Input UV data disk drive #   
AIPS 1: SOURCES    *all ' '                Source name                  
AIPS 1: QUAL         -1                    Calibrator qualifier -1=>all 
AIPS 1: CALCODE    '    '                  Calibrator code '    '=>all  
AIPS 1: TIMERANG   *all 0                  Time range to use            
AIPS 1: SELBAND      -1                    Bandwidth to select (kHz)    
AIPS 1: SELFREQ      -1                    Frequency to select (MHz)    
AIPS 1: FREQID       -1                    Freq. ID to select.          
AIPS 1: SUBARRAY      0                    Sub-array, 0=>all            
AIPS 1: DOCALIB      -1                    If >0 calibrate data         
AIPS 1: GAINUSE       0                    CL (or SN) table to apply    
AIPS 1: DOPOL        -1                    If >0.5 correct polarization.
AIPS 1: BLVER        -1                    BL table to apply.           
AIPS 1: FLAGVER       0                    Flag table version           
AIPS 1: DOBAND       -1                    If >0.5 apply bandpass cal.  
AIPS 1:                                    Method used depends on value 
AIPS 1:                                    of DOBAND (see HELP file).   
AIPS 1: BPVER        -1                    Bandpass table version       
AIPS 1: SMOOTH     *all 0                  Smoothing function. See      
AIPS 1:                                    HELP SMOOTH for details.     
AIPS 1: STOKES     '    '                  Stokes parameters (see HELP) 
AIPS 1: BCHAN         1                    Low freq. channel 0 for cont.
AIPS 1: ECHAN       128                    Highest freq channel         
AIPS 1: CHANNEL       0                    Restart channel number       
AIPS 1: NPOINTS       1                    Number of chan. to average.  
AIPS 1: CHINC         1                    Channel incr. between maps.  
AIPS 1: BIF           0                    First IF in average.         
AIPS 1: EIF           0                    Last IF in average.          
AIPS 1: OUTNAME    'D1-N1C1     '          Output image name (name)     
AIPS 1: OUTDISK       1                    Output image disk drive #    
AIPS 1: OUTSEQ        0                    Output seq. no.              
AIPS 1: OUTVER        0                    CC ver. no (Continuum only)  
AIPS 1:                                    *** SET OUTVER ON RESTARTS   
AIPS 1: IN2NAME    '            '          UV work file name            
AIPS 1: IN2CLASS   '      '                UV work file class           
AIPS 1: IN2SEQ        0                    UV work file seq             
AIPS 1: IN2DISK       0                    UV work file disk            
AIPS 1: CELLSIZE      0.5         0.5      (X,Y) size of grid in asec   
AIPS 1: IMSIZE      256         256        Minimum image size           
AIPS 1: NFIELD        1                    Number of fields (max. 64)   
AIPS 1: DO3DIMAG     -1                    > 0 => use different tangent 
AIPS 1:                                    points for each field        
AIPS 1: FLDSIZE    *all 0                  Size of each field.          
AIPS 1: RASHIFT    *all 0                  RA shift per field (asec)    
AIPS 1: DECSHIFT   *all 0                  DEC shift per field (asec)   
AIPS 1: UVTAPER       0           0        (U,V) Gaussian taper         
AIPS 1:                                      units are kilo-lambda      
AIPS 1: UVRANGE       0           0        Min & max baseline (klambda) 
AIPS 1: GUARD         0           0        x,y guard band fractional    
AIPS 1:                                    radius                       
AIPS 1: ROTATE        0                    Rotate image CCW from N by   
AIPS 1:                                    ROTATE degrees               
AIPS 1: ZEROSP     *all 0                  0-spacing fluxes and weights 
AIPS 1:                                    SEE HELP!!                   
AIPS 1: UVWTFN     'NA'                    UV dist. weight function     
AIPS 1:                                      blank => uniform           
AIPS 1: UVSIZE        0           0        Array size for doing uniform 
AIPS 1:                                    weights.  0 -> actual field  
AIPS 1:                                    size.                        
AIPS 1: ROBUST        0                    Robustness power: -5 -> pure 
AIPS 1:                                    uniform weights, 5 => natural
AIPS 1: UVBOX         0                    Additional rows and columns  
AIPS 1:                                    used in weighting.           
AIPS 1: UVBXFN        1                    Box function type when UVBOX 
AIPS 1:                                    > 0.  0 -> 1 round pill box. 
AIPS 1: XTYPE         5                    Conv. function type in x     
AIPS 1:                                      default spheroidal         
AIPS 1: YTYPE         5                    Conv. function type in y     
AIPS 1:                                      default spheroidal         
AIPS 1: XPARM      *all 0                  Conv. function parms for x   
AIPS 1: YPARM      *all 0                  Conv. function parms for y   
AIPS 1: NITER         0                    Maximum # of Clean components
AIPS 1: BCOMP      *all 0                  Begin at BCOMP component     
AIPS 1:                                    Specify for each field.      
AIPS 1: NBOXES        0                    Number of boxes for Clean    
AIPS 1:                                    NB: field 1 only.            
AIPS 1: CLBOX      *all 0                  Four coordinates for each box
AIPS 1: BOXFILE    *all ' '                Input file of field params   
AIPS 1:                                    and Clean boxes; ' ' => use  
AIPS 1:                                    FLDSIZE, RASHIFT, DECSHIFT,  
AIPS 1:                                    NBOXES, CLBOX only.          
AIPS 1: OBOXFILE   *all ' '                Output file for final Clean  
AIPS 1:                                    boxes                        
AIPS 1: GAIN          0.1                  Clean loop gain              
AIPS 1: FLUX          0                    Minimum Clean component (Jy) 
AIPS 1: MINPATCH     51                    Min. BEAM half-width in AP.  
AIPS 1: BMAJ          0                    FWHM(asec) major axis Clean  
AIPS 1:                                    restoring beam.              
AIPS 1: BMIN          0                    FWHM(asec) minor axis Clean  
AIPS 1:                                    restoring beam.              
AIPS 1: BPA           0                    Clean beam position angle    
AIPS 1: OVERLAP       0                    1 => restore components to   
AIPS 1:                                    overlapped fields, 2=> expect
AIPS 1:                                    overlaps while Cleaning      
AIPS 1: PHAT          0                    Prussian hat height.         
AIPS 1: FACTOR        0                    Speedup factor see HELP      
AIPS 1: CMETHOD    '    '                  Modeling method:             
AIPS 1:                                    'DFT','GRID','    '          
AIPS 1: CPARM      *all 0                  Task enrichment parameters   
AIPS 1:                                    (1) Antenna diameter (m)     
AIPS 1:                                    (2) Source Spectral index    
AIPS 1:                                    (3) Frequency scaling factor 
AIPS 1:                                    (4) >0 => do DFT imaging     
AIPS 1:                                        (not allowed for now)    
AIPS 1:                                    (5) >0 => scale residuals    
AIPS 1:                                    (6) Half-width in x of box   
AIPS 1:                                    (7) Half-width in y of box   
AIPS 1:                                    (10) multiplier of image size
AIPS 1:                                    to get beam size: 0 => 2;    
AIPS 1:                                    2, 1, 0.5 0.25 supported     
AIPS 1: MAXPIXEL      0                    Maximum pixels searched in   
AIPS 1:                                    each major cycle.            
AIPS 1: DOTV         -1                    Display residuals on TV ?    
AIPS 1:                                    Start with field = DOTV      
AIPS 1: BADDISK    *all 0                  Disks to avoid for scratch.  
>
>go imagr
IMAGR1: Task IMAGR  (release of 15APR99) begins
IMAGR1: FNDPOL: Stokes I computed assuming V=0
IMAGR1: FNDPOL: Stokes I computed assuming V=0
IMAGR1: FNDPOL: Stokes I computed assuming V=0
IMAGR1: Create D1OBJ_BC    .IMAGR .   1 (UV)  on disk  1  cno    8 ← work fileが生成された
AIPS 1: Resumes                                                   
>IMAGR1: Create D1-N1C1     .IBEM  .   1 (MA)  on disk  1  cno    9 ← beam patternの画像ファイルが生成された
IMAGR1: Create D1-N1C1     .IMAP  .   1 (MA)  on disk  1  cno   10 ←画像ファイルが生成された
IMAGR1: Beginning channel    1 through    1 with  1 IFs
IMAGR1: TABLE TYPE AN VERSION   1 DOES NOT EXIST
IMAGR1: PROBLEM OPENING TABLE OBJECT: Temporary AN table for IMACPY
IMAGR1: FAILS to get AN table data for parallactic and zenith angles
IMAGR1: FNDPOL: Stokes I computed assuming V=0
IMAGR1: IMACPY: Copied     2346 visibilities to be imaged
IMAGR1: GRDFLT: X and Y convolution type = SPHEROIDAL
IMAGR1: GRDFLT: X and Y parms =  3.0000  1.0000
IMAGR1: GRDFLT: convolution function sampled every 1/100 of a cell
IMAGR1: GRDMEM: Frequency 8.840800e+10 Hz
IMAGR1: Field  1 Sum of gridding weights =  2.49058e+04
IMAGR1: Field  1 Beam min = -210.6 MilliJy, max =    1.0      Jy
IMAGR1: Fit Gaussian FWHM =    9.455 x    6.243      arcsec, PA=  -65.5
IMAGR1: Field  1 min = -110.4 MilliJy,max =  118.1 MilliJy
IMAGR1: No Cleaning requested
IMAGR1: Beginning channel    2 through    2 with  1 IFs
IMAGR1: FNDPOL: Stokes I computed assuming V=0
IMAGR1: GRDMEM: Frequency 8.841600e+10 Hz
IMAGR1: Field  1 Sum of gridding weights =  1.15049e+05
IMAGR1: Field  1 Beam min = -162.0 MilliJy, max =    1.0      Jy
IMAGR1: Fit Gaussian FWHM =    9.333 x    6.744      arcsec, PA=  -67.8
IMAGR1: Field  1 min =  -57.4 MilliJy,max =   73.4 MilliJy
IMAGR1: No Cleaning requested
IMAGR1: Beginning channel    3 through    3 with  1 IFs
IMAGR1: FNDPOL: Stokes I computed assuming V=0
IMAGR1: GRDMEM: Frequency 8.842400e+10 Hz
IMAGR1: Field  1 Sum of gridding weights =  2.59592e+05
IMAGR1: Field  1 Beam min = -190.8 MilliJy, max =    1.0      Jy
IMAGR1: Fit Gaussian FWHM =    8.350 x    6.883      arcsec, PA=  -64.7
IMAGR1: Field  1 min =  -28.9 MilliJy,max =   23.5 MilliJy
IMAGR1: No Cleaning requested
IMAGR1: Beginning channel    4 through    4 with  1 IFs

(途中省略)

IMAGR1: GRDMEM: Frequency 8.940000e+10 Hz
IMAGR1: Field  1 Sum of gridding weights =  2.74454e+05
IMAGR1: Field  1 Beam min = -153.5 MilliJy, max =    1.0      Jy
IMAGR1: Fit Gaussian FWHM =    8.008 x    6.777      arcsec, PA=  -65.3
IMAGR1: Field  1 min =  -14.7 MilliJy,max =   16.6 MilliJy
IMAGR1: No Cleaning requested
IMAGR1: Beginning channel  126 through  126 with  1 IFs
IMAGR1: FNDPOL: Stokes I computed assuming V=0
IMAGR1: GRDMEM: Frequency 8.940800e+10 Hz
IMAGR1: Field  1 Sum of gridding weights =  2.74231e+05
IMAGR1: Field  1 Beam min = -153.5 MilliJy, max =    1.0      Jy
IMAGR1: Fit Gaussian FWHM =    8.009 x    6.779      arcsec, PA=  -65.3
IMAGR1: Field  1 min =  -16.0 MilliJy,max =   18.2 MilliJy
IMAGR1: No Cleaning requested
IMAGR1: Beginning channel  127 through  127 with  1 IFs
IMAGR1: FNDPOL: Stokes I computed assuming V=0
IMAGR1: GRDMEM: Frequency 8.941600e+10 Hz
IMAGR1: Field  1 Sum of gridding weights =  2.72872e+05
IMAGR1: Field  1 Beam min = -153.6 MilliJy, max =    1.0      Jy
IMAGR1: Fit Gaussian FWHM =    8.026 x    6.783      arcsec, PA=  -65.3
IMAGR1: Field  1 min =  -19.4 MilliJy,max =   21.1 MilliJy
IMAGR1: No Cleaning requested
IMAGR1: Beginning channel  128 through  128 with  1 IFs
IMAGR1: FNDPOL: Stokes I computed assuming V=0
IMAGR1: GRDMEM: Frequency 8.942400e+10 Hz
IMAGR1: Field  1 Sum of gridding weights =  2.55079e+05
IMAGR1: Field  1 Beam min = -155.5 MilliJy, max =    1.0      Jy
IMAGR1: Fit Gaussian FWHM =    8.142 x    6.795      arcsec, PA=  -64.9
IMAGR1: Field  1 min =  -23.8 MilliJy,max =   23.1 MilliJy
IMAGR1: No Cleaning requested
IMAGR1: Checking image max/min
IMAGR1: Appears to have ended successfully
IMAGR1: mpu2m        15APR99 NEW: Cpu=      82.5  Real=      85

これで、イメージデータ(目的天体の画像、合成ビーム)および work fileが生成されました。

>pcat
AIPS 1: Catalog on disk  1                                              
AIPS 1:  Cat Usid Mapname      Class   Seq  Pt     Last access      Stat
AIPS 1:    1    1 D1REF_B     .UVDATA.    1 UV 28-AUG-2003 02:28:41     
AIPS 1:    2    1 D1BPC_B     .UVDATA.    1 UV 28-AUG-2003 02:01:26     
AIPS 1:    3    1 D1OBJ_B     .UVDATA.    1 UV 28-AUG-2003 02:29:43     
AIPS 1:    4    1 D1BPC       .BPT   .    1 UV 28-AUG-2003 02:29:43     
AIPS 1:    5    1 D1REF_B     .GAT   .    1 UV 28-AUG-2003 02:29:43     
AIPS 1:    6    1 D1OBJ_BC    .UVDATA.    1 UV 28-AUG-2003 02:33:11     
AIPS 1:    7    1 D1OBJ_BC    .CLP3  .    1 UV 28-AUG-2003 02:55:12     
AIPS 1:    8    1 D1OBJ_BC    .IMAGR .    1 UV 28-AUG-2003 02:55:12     
AIPS 1:    9    1 D1-N1C1     .IBEM  .    1 MA 28-AUG-2003 02:55:14     
AIPS 1:   10    1 D1-N1C1     .IMAP  .    1 MA 28-AUG-2003 02:55:14  

2. スペクトルをみる

実行例

>task 'ispec'
>getn 10
AIPS 2: Got(1)   disk= 1  user=   1   type=MA   D1-N1C1.IMAP.1          
>inp
AIPS 2: ISPEC : Task to plot spectrum of a specified portion of an image
AIPS 2: Adverbs         Values            Comments                      
AIPS 2: ----------------------------------------------------------------
AIPS 2: USERID        0                    User ID.  0=>current user    
AIPS 2:                                      32000=>all users           
AIPS 2: INNAME     'D1-N1C1     '          Image name (name)            
AIPS 2: INCLASS    'IMAP  '                Image name (class)           
AIPS 2: INSEQ         1                    Image name (seq. #)          
AIPS 2: INDISK        0                    Disk drive #                 
AIPS 2: BLC        *all 0                  Bottom left corner of image  
AIPS 2:                                      0=>entire image            
AIPS 2: TRC        *all 0                  Top right corner of image    
AIPS 2:                                      0=>entire image            
AIPS 2: PIXRANGE      0           0        Range of intensities to plot 
AIPS 2: ZINC          1                    Increment on freq axis.      
AIPS 2: LTYPE         3                    Type of labeling: 1 border,  
AIPS 2:                                    2 no ticks, 3 standard, 4 rel
AIPS 2:                                    to center, 5 rel to subim cen
AIPS 2:                                    6 pixels. <0 -> no date/time.
AIPS 2: DOCENTER      1                    > 0 => plot with box-like    
AIPS 2:                                    lines, else plot line to     
AIPS 2:                                    points                       
AIPS 2: DOTV         -1                    > 0 Do plot on the TV, else  
AIPS 2:                                    make a plot file             
AIPS 2: GRCHAN        0                    Graphics channel 0 => 1.     
AIPS 2: DOCRT        -1                    > 0 => use the terminal, 0 =>
AIPS 2:                                    no output, < 0 => printer or 
AIPS 2:                                    file, > 72 => terminal width 
AIPS 2: OUTPRINT   '                                                '   
AIPS 2:                                    Printer disk file to save    
>imh  ← headerを見る
AIPS 1: Image=D1OBJ_BC  (MA)         Filename=D1-N1C1     .IMAP  .   1  
AIPS 1: Telescope=                                                      
AIPS 1: Observer=Kohno               User #=    1                       
AIPS 1: Observ. date=15-APR-2001     Map date=28-AUG-2003               
AIPS 1: Minimum=-1.10419556e-01      Maximum= 1.56641617e-01 JY/BEAM    
AIPS 1: ----------------------------------------------------------------
AIPS 1: Type    Pixels   Coord value     at Pixel     Coord incr   Rotat
AIPS 1: RA---SIN   256    02 38 07.980     128.00      -0.500000    0.00
AIPS 1: DEC--SIN   256    59 23 24.900     129.00       0.500000    0.00
AIPS 1: FREQ       128   8.8408000e+10       1.00  8.0000000e+06    0.00
AIPS 1: STOKES       1   1.0000000e+00       1.00  1.0000000e+00    0.00
AIPS 1: ----------------------------------------------------------------
AIPS 1: Coordinate equinox 1950.00                                      
AIPS 1: Map type=DIRTY               Number of iterations=       0      
AIPS 1: Conv size=   8.14 X   6.79   Position angle= -64.90             
AIPS 1: Maximum version number of extension files of type CC is   1     
AIPS 1: Maximum version number of extension files of type HI is   1     
>blc 128,129  ←画像の中心点(この観測では、とある銀河の中心核に一致させている)を指定
>trc blc  ← trc = blcの意味。これで、中心1点のみを指定していることになる
>inp
AIPS 1: ISPEC : Task to plot spectrum of a specified portion of an image
AIPS 1: Adverbs         Values            Comments                      
AIPS 1: ----------------------------------------------------------------
AIPS 1: USERID        0                    User ID.  0=>current user    
AIPS 1:                                      32000=>all users           
AIPS 1: INNAME     'D1-N1C1     '          Image name (name)            
AIPS 1: INCLASS    'IMAP  '                Image name (class)           
AIPS 1: INSEQ         1                    Image name (seq. #)          
AIPS 1: INDISK        0                    Disk drive #                 
AIPS 1: BLC         128         129        Bottom left corner of image  
AIPS 1:            *rest 0                   0=>entire image            
AIPS 1: TRC         128         129        Top right corner of image    
AIPS 1:            *rest 0                   0=>entire image            
AIPS 1: OPTYPE     '    '                  'FLUX', else average         
AIPS 1: PIXRANGE      0           0        Range of intensities to plot 
AIPS 1: ZINC          1                    Increment on freq axis.      
AIPS 1: SMOOTH     *all 0                  Frequency smoothing function 
AIPS 1: LTYPE         3                    Type of labeling: 1 border,  
AIPS 1:                                    2 no ticks, 3 standard, 4 rel
AIPS 1:                                    to center, 5 rel to subim cen
AIPS 1:                                    6 pixels, 7-10 as 3-6 with   
AIPS 1:                                    only tick labels             
AIPS 1:                                    <0 -> no date/time           
AIPS 1: DOCENTER      1                    > 0 => plot with box-like    
AIPS 1:                                    lines, else plot line to     
AIPS 1:                                    points                       
AIPS 1: DOTV         -1                    > 0 Do plot on the TV, else  
AIPS 1:                                    make a plot file             
AIPS 1: GRCHAN        0                    Graphics channel 0 => 1.     
AIPS 1: DOCRT       132                    > 0 => use the terminal, 0 =>
AIPS 1:                                    no output, < 0 => printer or 
AIPS 1:                                    file, > 72 => terminal width 
AIPS 1: OUTPRINT   '                                                '   
AIPS 1:                                 
>go ispec
ISPEC1: Task ISPEC  (release of 15APR99) begins
ISPEC1: Created plot file version    1 plot fileが生成された
ISPEC1: GFINIS: number records used       6
ISPEC1: Appears to have ended successfully
ISPEC1: mpu2m        15APR99 NEW: Cpu=       0.0  Real=       0
AIPS 1: Resumes                
>go tkpl   生成されたplot fileをTK windowで表示
AIPS 1: Resumes                                                         
>TKPL 1: Appears to have ended successfully
TKPL 1: mpu2m        15APR99 NEW: Cpu=       0.0  Real=       1


表示されたスペクトル

1GHz幅の分光計帯域内に、2本の強いラインが入っていることが わかります。

表示させるチャンネルの範囲を指定して、1本のラインについて 拡大表示してみましょう。

>blc(3) 10; trc(3) 50  ←周波数チャンネル10から50までを表示
>pixrange -0.01 0.1   ←Y軸は-0.01Jyから0.1Jyまでに固定
>inp
AIPS 1: ISPEC : Task to plot spectrum of a specified portion of an image
AIPS 1: Adverbs         Values            Comments                      
AIPS 1: ----------------------------------------------------------------
AIPS 1: USERID        0                    User ID.  0=>current user    
AIPS 1:                                      32000=>all users           
AIPS 1: INNAME     'D1-N1C1     '          Image name (name)            
AIPS 1: INCLASS    'IMAP  '                Image name (class)           
AIPS 1: INSEQ         1                    Image name (seq. #)          
AIPS 1: INDISK        0                    Disk drive #                 
AIPS 1: BLC         128         129        Bottom left corner of image  
AIPS 1:              10        *rest 0       0=>entire image            
AIPS 1: TRC         128         129        Top right corner of image    
AIPS 1:              50        *rest 0       0=>entire image            
AIPS 1: OPTYPE     '    '                  'FLUX', else average         
AIPS 1: PIXRANGE     -0.01        0.1      Range of intensities to plot 
AIPS 1: ZINC          1                    Increment on freq axis.      
AIPS 1: SMOOTH     *all 0                  Frequency smoothing function 
AIPS 1: LTYPE         3                    Type of labeling: 1 border,  
AIPS 1:                                    2 no ticks, 3 standard, 4 rel
AIPS 1:                                    to center, 5 rel to subim cen
AIPS 1:                                    6 pixels, 7-10 as 3-6 with   
AIPS 1:                                    only tick labels             
AIPS 1:                                    <0 -> no date/time           
AIPS 1: DOCENTER      1                    > 0 => plot with box-like    
AIPS 1:                                    lines, else plot line to     
AIPS 1:                                    points                       
AIPS 1: DOTV         -1                    > 0 Do plot on the TV, else  
AIPS 1:                                    make a plot file             
AIPS 1: GRCHAN        0                    Graphics channel 0 => 1.     
AIPS 1: DOCRT       132                    > 0 => use the terminal, 0 =>
AIPS 1:                                    no output, < 0 => printer or 
AIPS 1:                                    file, > 72 => terminal width 
AIPS 1: OUTPRINT   '                                                '   
AIPS 1:                                    
>go
ISPEC1: Task ISPEC  (release of 15APR99) begins
ISPEC1: Created plot file version    6
ISPEC1: GFINIS: number records used       4
ISPEC1: Appears to have ended successfully
ISPEC1: mpu2m        15APR99 NEW: Cpu=       0.0  Real=       0
AIPS 1: Resumes                                                          
>go tkpl
TKPL 1: Task TKPL   (release of 15APR99) begins
AIPS 1: Resumes                                                         
>TKPL 1: Appears to have ended successfully
TKPL 1: mpu2m        15APR99 NEW: Cpu=       0.0  Real=       1


表示範囲を調節したスペクトル。

周波数表示ではなく、速度表示にするためには、 このデータにおける、速度と周波数の対応付けを 定義してやる必要があります(ALTDEF)。 この例の場合、2本のラインが入ってしまっているので、 それぞれ分けてからALTDEF(定義付け)する必要があります。 詳しくは別項にて。

3. contour mapをつくる

このマップをみると、強いemissionの両側に、negativeな値を 示す領域が広がっていることがわかります。これは、 synthesized beamがあまり「綺麗」でないことの影響です。 ためしに、IBEMというファイル(この例では、D1-N1C1.IBEM.1)を TVALLで表示させてみましょう。 IBEMというファイルは、point sourceをこのUV coverageで 観測したときに、どのように見えるか(可視でいうところの point spread function)を表しています(干渉計では synthesized beamと呼びます)。 これをみるとわかる通り、synthesized beamは、 単純なGaussianではなく、 peak levelに対して、10%程度の+や-のでこぼこを伴った 形状になっています(Fourier成分のサンプルが不完全なために起ります。 理想的なサンプル=uv domain上のすべての格子点がサンプルされれば、 synthesized beamはGaussianになる、という話が教科書に出ていましたね)。 ともあれ、synthsized beamがこのようなでこぼこを伴う形状であるため、 これを何らかの方法でdevonvolutionしてやる必要性が生じます。 可視等でもお馴染のMEMのほか、電波干渉計では、 CLEANという手法が広く用いられています。これを次のSTEPでやってみましょう。


[step-by-stepガイド] [STEP 1] [STEP 2] [STEP 3] [STEP 4] [STEP 5] [STEP 6] [FXのデータ処理]

[NMA データ処理ガイド] [共同利用観測ガイド] [NMA Home Page] [NRO Home Page]

Copyright (C) 1999-2005 Nobeyama Radio Observatory, NAOJ. All rights reserved.
Updated on: Friday, 09-Dec-2005 20:11:09 JST