[daip] IMAGR channel binning problem

[Eva Schinnerer]

Hi Eric,

Thanks very much for looking into this!

Here is the IMAGR input as Linda and I used it:

This is the call I used on the continuum subtracted UV data set to get  
ngc2805_test.fits:

default 'imagr';sources 'ngc2805','';calcode '';freqid 1;qual -1
timerang 0;selband -1;nfield 1;uvwtfn 'un';gain 0.1;bmaj 0
selfreq -1;subarray 0;docalib -1;gainuse 2;dopol -1;blver -1;
flagver 1;doband -1;bpver 1;smooth 0;stokes '';bchan 1;echan 0
channel 0;bif 0;eif 0;outdisk 0;outseq 1;outver 0;in2name ''
in2class '';in2seq 1;in2disk 0;do3dimag -1;fldsize 0;rashift 0
decshift 0;uvtaper 0 0;uvrange 0 0;guard 0 0;rotate 0;zerosp 0
uvsize 0 0;uvbox 0;uvbxfn 1;xtype 5;ytype 5;xparm 0;yparm 0
bcomp 0;allokay 0;boxfile '';oboxfile '';minpatch 51;overlap 0
phat 0;factor 0;cmethod '';imagrprm 0;ngauss 0;wgauss 0;fgauss 0
maxpixel 0;bpa 0;bmin 0

outname 'ngc2805-test'
cellsize 4
imsize 512
robust 5
niter 0
nboxes 1
clbox 0
flux 0
nchav 2
chinc 2
dotv -1

getn 24
go imagr

You can find the file that is causing the problems on my ftp-site at:

ftp.mpia.de/pub/schinner/am942_ngc2805_line_uvlin.fits

Thanks very much,
      eva


On May 23, 2009, at 5:29 PM, Eric Greisen wrote:

> Eva Schinnerer wrote:
>> Hi Eric,
>> Here is the promised email. We used the NCHAV and NINC set to 2 to  
>> bin the velocity axis to increase the S/N in our HI data cube. The  
>> original data cube looked fine, whereas the newly binned datacube  
>> looked a continuum image. The data cube was continuum subtracted  
>> with UVLIN.
>> Please let me know if we only experienced this problem and I can  
>> send you the data that caused this problem.
>> Thanks very much,
>>   eva
>
> I tried this on my NGC6503 data set.  I ran IMAGR with NCHAV=2;  
> CHINC=2 with both a gnu-compiler version and the faster Intel- 
> compiler version which we send with binary installations.  I also  
> then ran UVCOP with APARM(1) 1; NCHAV=2; CHINC=2 and reran IMAGR  
> with NCHAV=1; CHINC=1.
> All three produced nearly identical results, all of which looked fine.
>
> I guess I am going to need your data set and your inputs to IMAGR.
>
> Eric Greisen
>