[daip] New Ticket - [!VFT-650742]: EVLA Data In AIPS

John Michael Cannon do-not-reply at nrao.edu
Mon Jul 19 11:20:09 EDT 2010


New Ticket: EVLA Data In AIPS

I hope that you might be able to provide some guidance on data acquired for program 10B-187.  I have in hand three raw datasets, 2 hours each in D-array, for 2 galaxies (1 galaxy was observed twice).  I am attempting to calibrate these data in AIPS and have run into some fairly significant headaches.  If you don't have time to help that is fine, I can submit a help ticket, just let me know.

First off, I am running 31DEC10 AIPS and have followed the basic guidelines in Appendix E of the AIPS Cookbook ("Handling EVLA Data in AIPS").  Running through that pipeline, I end up with data with an unacceptably poor CALIB solution. 

Since the original data are of high spectral resolution, I modified this pipeline slightly to move from 256 to 64 channels.  Specifically, I flagged data, then applied SPLAT/INDXR/SPECR/UVSRT/INDXR, then proceeded with the nominal sequence as in the AIPS cookbook.  I include my work file below, showing the sequence of steps that I have applied (sorry it is a bit long).  The most serious issue is the very poor phase solutions for the phase cal; there are large phase jumps between all scans, and after experimenting with various smoothing intervals in CLCAL I cannot achieve phases better than +/- 20-30 degrees.  Also, the results of GETJY disagree with the calibrator manual by more than a factor of 2. 

The problems I note here (for the data acquired June 22) are present in the other two datasets as well.  For that reason I am hoping that the issue is perhaps related to the application of FRING, BPASS or other tasks introduced with the new EVLA data.

Any advice you might be able to provide would be most appreciated.  

--------------------------------
---- Log file follows below ----
--------------------------------

User number 5004; AGC749237, observed June 22

1. UVLOD: load data

   default 'uvlod'; bcount 0;
   ncount 0;
   datain 'VLADATA:AC990_AGC749237B'; douvcomp -1;
   outna 'AGC749237B'; outcl 'UVDATA'; outseq 0;
   outdi 1; doall 1; npoints 0;

   --> 2520531 visibilities

2. INDXR
   task 'indxr'; getn 1;
   infile ''; prtlev 0; cparm 0,0,0.5;
   bparm 0,0; go

INDXR1: Warning:  0.400  percent of times not found in WX table
    This may be a normal amount

3. LISTR
   default 'listr'; getn 1;
   optype 'scan'; docrt 132;
   go

Scan summary listing
 
Scan      Source      Qual  Calcode Sub         Timerange          FrqID   START VIS  END V
   1 1331+305=3C286  : 0000           1  0/02:09:50 -   0/02:10:50     1       1      21060
   2 1331+305=3C286  : 0000  K        1  0/02:10:51 -   0/02:19:48     1   21061     210249
   3 J1221+2813      : 0000  D        1  0/02:19:49 -   0/02:23:47     1  210250     294138
   4 AGC749237       : 0000           1  0/02:23:49 -   0/02:56:02     1  294139     973323
   5 J1221+2813      : 0000  D        1  0/02:56:03 -   0/02:59:01     1  973324    1036152
   6 AGC749237       : 0000           1  0/02:59:03 -   0/03:31:16     1 1036153    1715337
   7 J1221+2813      : 0000  D        1  0/03:31:17 -   0/03:34:16     1 1715338    1778166
   8 AGC749237       : 0000           1  0/03:34:17 -   0/04:06:30     1 1778167    2457351
   9 J1221+2813      : 0000  D        1  0/04:06:31 -   0/04:09:31     1 2457352    2520531
 
Source summary
Velocity type = '        '    Definition = '        '
 
  ID Source           Qual  Calcode RA(2000.0)     Dec(2000.0)  No. vis
   1 1331+305=3C286  : 0000         13:31:08.2880  30:30:32.959   21060
   2 1331+305=3C286  : 0000   K     13:31:08.2880  30:30:32.959  189189
   3 J1221+2813      : 0000   D     12:21:31.6905  28:13:58.500  272727
   4 AGC749237       : 0000         12:26:23.4000  27:44:44.000 2037555
 
  ID Source            Freq(GHz) Velocity(Km/s) Rest freq (GHz)
   1 All Sources          1.4204         0.0000          0.0000
 
Frequency Table summary
FQID IF#      Freq(GHz)      BW(kHz)   Ch.Sep(kHz)  Sideband
   1   1       1.42040575    1000.0001      3.9063      1

4. PTRAN
   task 'prtan'; optype 'scan'; docrt 132; go

                      Location of VLA antennas
 
                               N09 (18)*
                               N08 (28)*
                               N07 (13)*
                                   (  )
                               N05 (20)*
                               N04 (22)*
                               N03 (10)*
                               N02 (25)*
                               N01 ( 8)*
                          *( 4) W01  E01 (21)*
                        *(16) W02      E02 ( 2)*
                      *(26) W03          E03 (27)*
                    *(19) W04              E04 (11)*
                  *(24) W05                  E05 (14)*
                *(15) W06                      E06 ( 9)*
              *(17) W07                          E07 (23)*
            *( 5) W08                              E08 (12)*
          *( 1) W09                                  E09 ( 3)*
                          MAS      ( 6)
                                   ( 7)
* => EVLA ANTENNA

5. VLANT
   task 'vlant';
   default 'vlant'; getn 1; go

************************************************************************
**** BEGIN EXAMINING DATA ****
****
**** EVLA OPERATOR LOG COMMENTS FOLLOW
****
**** Antenna(s):6 10 do not have good baseline positions
****
**** ANTENNAS 6, 10, 17, 20: DATA LOST, L-band receiver not yet installed.
****
************************************************************************

**** FLAG ANTENNAS 6, 10, 17, 20 FOR ALL DATA, REASON = 'NO L RECEIVERS'

UVFLG - remove the data discussed above

task 'uvflg'; default uvflg;
getn 1; sources '';
subarray 0; selband -1; selfreq -1;
freqid -1; timerang 0; bchan 0; echan 0;
bif 0; eif 0;
antennas 6,10,17,20; baseline 0;
stokes ''; aparm 0;
opcode 'FLAG';
reason 'no l receivers';
dohist 1; inp

*** Examine data:

-->   tvreset; tvclear;
   task 'tvflg'; default tvflg;
   getn 1; docat -1;
   dohist -1; sources ''; calcode 'K';
   timerang 0; stokes 'RR'; selband -1;
   selfreq -1; freqid 1; bif 0; eif 0;
   bchan 157; echan 177; antennas 0;
   baseline 0; uvrange 0; subarray 0;
   docalib 1; gainuse 0; blver -1;
   flagver 0; doband -1; bpver -1;
   smooth 0; dparm(6)=1; baddisk 0;
   go

   --> Ant 16 RR is systematically high

-->      tvreset; tvclear;
   task 'tvflg'; default tvflg;
   getn 1; docat -1;
   dohist -1; sources ''; calcode 'K';
   timerang 0; stokes 'LL'; selband -1;
   selfreq -1; freqid 1; bif 0; eif 0;
   bchan 197; echan 207; antennas 0;
   baseline 0; uvrange 0; subarray 0;
   docalib 1; gainuse 0; blver -1;
   flagver 0; doband -1; bpver -1;
   smooth 0; dparm(6)=1; baddisk 0;
   go

   --> Ant 16 LL looks ok

-->         tvreset; tvclear;
   task 'tvflg'; default tvflg;
   getn 1; docat -1;
   dohist -1; sources 'J1221+2813';
   calcode 'D';
   timerang 0; stokes 'RR'; selband -1;
   selfreq -1; freqid 1; bif 0; eif 0;
   bchan 118; echan 138; antennas 0;
   baseline 0; uvrange 0; subarray 0;
   docalib 1; gainuse 0; blver -1;
   flagver 0; doband -1; bpver -1;
   smooth 0; dparm(6)=1; baddisk 0;
   go

   --> Ants 16, 25 look deviant in RR

-->         tvreset; tvclear;
   task 'tvflg'; default tvflg;
   getn 1; docat -1;
   dohist -1; sources 'J1221+2813';
   calcode 'D';
   timerang 0; stokes 'LL'; selband -1;
   selfreq -1; freqid 1; bif 0; eif 0;
   bchan 157; echan 177; antennas 0;
   baseline 0; uvrange 0; subarray 0;
   docalib 1; gainuse 0; blver -1;
   flagver 0; doband -1; bpver -1;
   smooth 0; dparm(6)=1; baddisk 0;
   go

   --> No major issues are apparent here.

-->    tvreset; tvclear;
   task 'tvflg'; default tvflg;
   getn 1; docat -1; calcode '';
   dohist -1; sources 'AGC749237';
   timerang 0; stokes 'RR'; selband -1;
   selfreq -1; freqid 1; bif 0; eif 0;
   bchan 139; echan 159; antennas 0;
   baseline 0; uvrange 0; subarray 0;
   docalib 1; gainuse 0; blver -1;
   flagver 0; doband -1; bpver -1;
   smooth 0; dparm(6)=1; baddisk 0;
   go

   --> ANT 25 is bad in RR

-->    tvreset; tvclear;
   task 'tvflg'; default tvflg;
   getn 1; docat -1; calcode '';
   dohist -1; sources 'AGC749237';
   timerang 0; stokes 'LL'; selband -1;
   selfreq -1; freqid 1; bif 0; eif 0;
   bchan 118; echan 138; antennas 0;
   baseline 0; uvrange 0; subarray 0;
   docalib 1; gainuse 0; blver -1;
   flagver 0; doband -1; bpver -1;
   smooth 0; dparm(6)=1; baddisk 0;
   go

   --> LL stokes looks good. 

XXXXXXX Flag Antennas 16, 26, RR stokes:

task 'uvflg'; default uvflg;
getn 1; sources '';
subarray 0; selband -1; selfreq -1;
freqid -1; timerang 0; bchan 0; echan 0;
bif 0; eif 0;
antennas 16,25; baseline 0;
stokes 'RR'; aparm 0;
opcode 'FLAG';
reason 'Deviant Amplitudes'
dohist 1; inp

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXX Next apply SPLAT, applying the flagging commands and creating a new multi-source dataset
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

6.  Task 'SPLAT'; default splat;
getn 1; sources '';
qual -1; calcode ''; timerang 0;
stokes ''; selband 0; selfreq 0;
freqid 1; bif 0; eif 0; bchan 0;
echan 0; subarray 0; docalib 0;
gainuse 0; dopol -1; blver -1;
flagver 0; doband -1; bpver 0; 
smooth 0; outname inname;
outclass 'UVdat2'; outseq 0;
outdisk 1; douvcomp -1; aparm 0;
ichansel 0; channel 0; chinc 1;
solint 0; baddisk 0;
inp

**** Apply INDXR to re-index the output files:

task 'indxr'; getn 2; infile ''
prtlev 0; cparm 0; bparm 0;
cparm 0,0,0.5;
in2file ''; go

-- Checked visibilities, things look good, all flags show up as
expected. 

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXX   NEXT, SPECTRAL AVERAGE BY 4x VIA "SPECR"
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

7. SPECR - average data in spectral domain, creating yet another new UV database.

task 'specr'; default specr
getn 2; outname inname;
outclass 'specr';
npoints 64;

-- output file needs to be sorted:

task 'uvsrt'; default uvsrt;
getn 3;
outname inname; outclass 'uvsrt';
sort 'TB'

task 'indxr'; default indxr;
getn 4; go

8. FRING
   -Selected 00:02:15:00-00:02:19:00 on 1331+305

   task 'fring'; default fring;
   refant 8;
   getn 4; timerang 00 02 15 00 00 02 19 00;
   calsour '1331+305=3C286'; calcode 'K';
   solint 4.1; dparm(9)=1;

   --> FINDS 44 GOOD SOLUTIONS, FAILS on 2 solutions.

--> The SN table needs to be applied to the main CL table created by INDXR:

9. CLCAL
   task 'clcal'; default 'clcal';
   getn 4;
   timerang 0; gainuse 0; gainver 0;
   snver 1; inver 1;
   calsour '1331+305=3C286'; calcode 'K';

10. More detailed TVFLG on primary, phase, source

   tvreset; tvclear;
   task 'tvflg'; default tvflg;
   getn 4; docat -1;
   dohist -1; sources ''; calcode 'K';
   timerang 0; stokes 'RR'; selband -1;
   selfreq -1; freqid 1; bif 0; eif 0;
   bchan 28; echan 32; antennas 0;
   baseline 0; uvrange 0; subarray 0;
   docalib 1; gainuse 0; blver -1;
   flagver 0; doband -1; bpver -1;
   smooth 0; dparm(6)=1; baddisk 0;
   go

   tvreset; tvclear;
   task 'tvflg'; default tvflg;
   getn 4; docat -1;
   dohist -1; sources ''; calcode 'K';
   timerang 0; stokes 'LL'; selband -1;
   selfreq -1; freqid 1; bif 0; eif 0;
   bchan 28; echan 32; antennas 0;
   baseline 0; uvrange 0; subarray 0;
   docalib 1; gainuse 0; blver -1;
   flagver 0; doband -1; bpver -1;
   smooth 0; dparm(6)=1; baddisk 0;
   go

   tvreset; tvclear;
   task 'tvflg'; default tvflg;
   getn 4; docat -1;
   dohist -1; sources 'J1221+2813';
   calcode 'D';
   timerang 0; stokes 'RR'; selband -1;
   selfreq -1; freqid 1; bif 0; eif 0;
   bchan 28; echan 32; antennas 0;
   baseline 0; uvrange 0; subarray 0;
   docalib 1; gainuse 0; blver -1;
   flagver 0; doband -1; bpver -1;
   smooth 0; dparm(6)=1; baddisk 0;
   go

   tvreset; tvclear;
   task 'tvflg'; default tvflg;
   getn 4; docat -1;
   dohist -1; sources 'J1221+2813';
   calcode 'D';
   timerang 0; stokes 'LL'; selband -1;
   selfreq -1; freqid 1; bif 0; eif 0;
   bchan 28; echan 32; antennas 0;
   baseline 0; uvrange 0; subarray 0;
   docalib 1; gainuse 0; blver -1;
   flagver 0; doband -1; bpver -1;
   smooth 0; dparm(6)=1; baddisk 0;
   go

   tvreset; tvclear;
   task 'tvflg'; default tvflg;
   getn 4; docat -1; calcode '';
   dohist -1; sources 'AGC749237';
   timerang 0; stokes 'RR'; selband -1;
   selfreq -1; freqid 1; bif 0; eif 0;
   bchan 28; echan 32; antennas 0;
   baseline 0; uvrange 0; subarray 0;
   docalib 1; gainuse 0; blver -1;
   flagver 0; doband -1; bpver -1;
   smooth 0; dparm(6)=1; baddisk 0;
   go

--> Antnenna 5 has some issues.  Keep an eye on this. 
--> Antenna 19 has a large segment flagged.

   tvreset; tvclear;
   task 'tvflg'; default tvflg;
   getn 4; docat -1; calcode '';
   dohist -1; sources 'AGC749237';
   timerang 0; stokes 'LL'; selband -1;
   selfreq -1; freqid 1; bif 0; eif 0;
   bchan 28; echan 32; antennas 0;
   baseline 0; uvrange 0; subarray 0;
   docalib 1; gainuse 0; blver -1;
   flagver 0; doband -1; bpver -1;
   smooth 0; dparm(6)=1; baddisk 0;
   go

--> Antenna 19 has a large segment flagged. 

XXXXX  FLAGGING ANTENNA 19 LL & RR

task 'uvflg'; default uvflg;
getn 4; sources '';
subarray 0; selband -1; selfreq -1;
freqid -1; timerang 0; bchan 0; echan 0;
bif 0; eif 0;
antennas 19; baseline 0;
stokes ''; aparm 0;
opcode 'FLAG';
reason 'Misbehaving'
dohist 1; inp

11. POSSM; examine bandpasses & identify reliable sections
    -- Using antennas 4, 8, 21 (center of array) for BPASS examination
 
    tvreset;  tvclear;
    task 'possm'; default 'possm'
    getn 4; source '1331+305=3C286';
    calcode 'K'; stokes ''; bchan 0; echan 0;
    dotv 1; nplots 4; anten 4,8,21;
    baseline 0;
    docal 1; aparm 1,0;

    - Bandpass plots look ok between channels 10 and 56
    - Smoothing spectrally & editing data creates nicer
       bandpasses than we had previously.

12. BPASS; now using same time range as the FRING solution

    task 'bpass'; default 'bpass';
    getn 4; docal 1; solint 0; calcode 'K';
    timerang 00 02 15 00 00 02 19 00;
    calsour '1331+305=3C286'; ichansel 10,56,1,0;
    bpassprm(5)=1; bpassprm(10)=3; go

13.  POSSM - exmine bandpasses again, after BPASS has executed.

    tvreset;  tvclear;
    task 'possm'; default 'possm'
    getn 4; source '1331+305=3C286';
    calcode ''; stokes ''; bchan 0; echan 0;
    dotv 1; nplots 4;
    anten 4,8,21; baseline 4,8,21;
    docal 1; aparm 1,0; doband 3;

-- Few antennas I examined look ok; phases +/- 2 degrees, with ammplitudes more or
   less constant across bandpasses. 

14. SETJY:  MAKE ABSOLUTELY SURE THAT calcode = '' (is blank)
    task 'setjy'; default 'setjy';
    getn 4; sources '1331+305=3C286';
    qual -1; bif 0; eif 0; zerosp 0;
    optype 'CALC'; calcode ''; sysvel 0;
    restfreq 0; veltyp ''; veldef '';
    freqid=1; aparm 0;
    go

    '1331+305=3C286  ' IF =  1 FLUX =14.7562 (Jy calcd)

15.  CALRD - read in a calibrator FITS image file
     task 'calrd';
     object '3c286'; band 'L'; go

16. CALIB; again applying same timerang as in BPASS and FRING

    task 'calib'; default 'calib'; getn 4;
    get2n 5; calcode 'K';  qual -1;
    timerang 00 02 15 00 00 02 19 00;
    refant 8; bpver 0; uvrange 0 18; 
    docal 1; doband 3; solin 4; nmaps 1;
    calsour '1331+305=3C286';
    ichansel 10,56,1,0;
    Aparm 4,0,0,0,0,2;
    Minamper 10;
    Minphser 10; Cparm 0,0,10,10,1;
    snver 2; inp;

    ---- RESULTS:  Found           42 good solutions
    ---- NO FAILURES, no closure errors

17. CALIB on phase cals
   
    clr2name; nmaps 0; solin 0;
    soltype ''; timerang 0;
    calsour 'J1221+2813'; calcode 'D';
    refant 8; bpver 0; uvrange 0;
    ichansel 10,56,1,0;
    Aparm 4,0,0,0,0,2;
    Minamper 15;
    Minphser 15; Cparm 0,0,10,10,1;
    snver 2;   
   
    ---- RESULTS:  210 good solutions
                  8 failed solutions
    --- Many many closure errors. 

18.  LISTR - examine solutions.  Amplitudes should be constant,
     gains should vary smoothly with time

Task 'LISTR'; getn 4; Optype 'Gain';
Inext 'SN'; Inver 0;  Sources '';
Calcode '*'; Timerang 0; Stokes '';
Selband -1; Selfreq -1; Freqid 1;
Bif 0; Eif 0; Bchan 1; Echan 0;
Antennas 0; Baseline 0; Uvrange 0;
Subarray 0; Docalib 2; Gainuse 0;
Dopol -1; Blver -1; Flagver 0;
Doband 3; Bpver 0; Smooth 0;
Dparm 5,0;  doacor 0; Factor 0;
Docrt -1; Outprint 'VLADATA:AGC749237.LISTR2';
baddisk 0;

-- SEVERE PHASE JUMPS.  Gain solutions OK, but PHASE solutions are awful:

RR:
02:23:36 J1221+28 -61 -58 -49 -54 -57       0 -54     -56 -54 -56 -63 -63         -64         -56 -62 -58 -59     -58 -57 -61
02:57:37 J1221+28-126-132-134-126-126       0-133    -134-136-129-134-132        -133        -131-135-126-132    -138-131-128
03:32:52 J1221+28  13   8  10  14  17       0   5      10   8   2   0   5           3          13   7  13   9       3  14   3
04:08:06 J1221+28  86  77  83  87  82       0  76      85  79  85  72  88          76          84  90  86  80      74  81  80

LL:
02:23:36 J1221+28 -64 -60 -55 -61 -64       0 -59     -60 -61 -61 -61 -62 -64     -66         -62 -63 -60 -64 -63 -60 -59 -62
02:57:37 J1221+28-127-133-136-130-126       0-134    -135-138-132-137-134-135    -136        -133-138-127-132-139-141-134-130
03:32:52 J1221+28  13   7   8  12  18       0   4      10   9   4   2   6   1       3          12   7  13  11   6   4  15   2
04:08:06 J1221+28  86  76  82  87  85       0  78      83  80  85  75  88  75      77          83  87  87  83  84  74  83  81


19. GETJY
    default 'getjy'; getn 4; source 'J1221+2813';
    calsour '1331+305=3C286'; bif 0; eif 0;
    inp

localh> GETJY1: Calibrator robust averaging used     92 of     92 gain samples
localh> GETJY1:    Source:Qual      CALCODE IF  Flux (Jy)
localh> GETJY1: J1221+2813      :  0   D     1    0.27920 +/-   0.00191  0.00191
localh> GETJY1:    Source:Qual    CALCODE    used   total     bad used  tot  bad
localh> GETJY1: J1221+2813      :  0 D        230     230       0   46   46    0

-- CALIBRATOR MANUAL STATES 0.86 Jy at L-band.  Severe disagreement.

20. CLCAL

    task 'clcal';
    default 'clcal'; getn 4; calcode '';
    snver 2; invers snver;
    BPARM 1 1 1 1 1 0;
    sources 'J1221+2813';
    calsour 'J1221+2813'; soucode '';
    freqid 1; interpol '2pt';
    samptype 'box'; icut 0;
    dobtween 0; refant 8;

21.  LISTR:  print outputs for phase cals.  Amplitudes should be roughly constant,
              while phases should be close to zero.

Task 'LISTR'; getn 4; Optype 'matx';
Inext 'SN'; Inver 0;  Sources '';
Calcode 'D'; Timerang 0; Stokes '';
Selband -1; Selfreq -1; Freqid 1;
Bif 0; Eif 0; Bchan 1; Echan 0;
Antennas 0; Baseline 0; Uvrange 0;
Subarray 0; Docalib 2; Gainuse 0;
Dopol -1; Blver -1; flagver 0;
Doband 3; Bpver 0; Smooth 0;
Dparm 5,1,0;  doacor 0; Factor 0;
Docrt -1; baddisk 0;
Outprint 'VLADATA:AGC749237.B.LISTR.CLCAL';

Task 'LISTR'; getn 4; Optype 'Gain';
Inext 'SN'; Inver 0;  Sources '';
Calcode '*'; Timerang 0; Stokes '';
Selband -1; Selfreq -1; Freqid 1;
Bif 0; Eif 0; Bchan 1; Echan 0;
Antennas 0; Baseline 0; Uvrange 0;
Subarray 0; Docalib 2; Gainuse 0;
Dopol -1; Blver -1; Flagver 0;
Doband 3; Bpver 0; Smooth 0;
Dparm 5,0;  doacor 0; Factor 0;
Docrt -1; Outprint 'VLADATA:AGC749237.B.LISTR2';
baddisk 0;

22.  REWAY - replaces SPLIT, applies calibration and attempts to get the
     data weighting correct.  Following suggestions in the EVLA guide, but
     will want to experiment with these assumptions later.

     task 'reway'; default 'reway'; getn 4;
     docal 1; doband 3;
     source 'AGC749237';
     aparm 11,30,12,0,10,4;
     calcode '-cal';
     outname 'agc749241';
     outclass 'split';
     bpver 0;
    
-- Output:  AGC749237.SPLIT    

23. IMAGR - would proceed as normal here ...

Ticket Details
===================
Ticket ID: VFT-650742
Department: AIPS Data Processing
Priority: Default
Status: Open
Link:  https://help.nrao.edu/staff/index.php?_m=tickets&_a=viewticket&ticketid=321




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