DDO63 is a THINGS galaxy. We already have the data calibrated and combined and continuum subtracted. Imaged by: Dana Ficut-Vicas ###To make a continuum map we thus need a proper cleaning down to a flux level which depends on how many line free channels we have. A quick and dirty IMAGR is necessary here to establish the flux level to clean down to. DEFAULT IMAGR sources '',''; docalib -1;doband -1;outseq 0; outname 'cont.dirt'; cellsize 1; imsize 2048; niter 1000; uvwtfn '';dotv -1; calcode '';robust 0.5; getn *.UVCONT Rms noise is: 0.194mJy DEFAULT IMAGR sources '',''; docalib -1;doband -1;outseq 0; outname 'continuum'; cellsize 1.5; imsize 2048; $in a complex field one might need 2048 niter 100000; uvwtfn ''; dotv -1; calcode '';robust 0.5; flux 2*0.194e-3 $it should be set to a 2 sigma level getn *.UVCONT Looks fine now!!! 7. Imaging executed on 14 September 2009 A. Noise TESTS: We need the rms noise in a line free channel as given by MSCLEAn with no cleaning.The rms noise is measured by setting a window with TVWIN and than running an IMSTAT.It is this noise level that we will further use with MSCLEAN. DEFAULT IMAGR sources '',''; docalib -1;doband -1;outseq 0; cellsize 1.5; imsize 1024; uvwtfn ''; dotv -1; calcode '-cal'; robust 0.5; ngauss 4;wgauss 0,15,45,135; fgaus 0 $ no fgauss levels are necessary as we are not cleaning niter 0 $no cleaning, we just want to quantify the rms noise nbox 1 clbox 230.00 270.00 780.00 820.00 $enough to hold all the signal in every channel $its size should have been decided at step 6C bchan 20;echan 25; $select one or more line free channels outn 'noise' imagrprm 0; imagrprm(10) 1; $multiplier of max image size to set beam size imagrprm(11) 0.2; $the alpha parameter, which steers MSCLEAN towards certain scale components The rms noise measured in a line free channel is: Field 1(5asec resolution): 1.12 mJy Field 2(15 asec resolution):1.37 mjy Field 3(45 asec resolution):1.86 mJy Field 4(135 asec resolution):3.47 mJy B. Tuning our multi-resolution clean parameters executed on DEFAULT IMAGR sources '',''; docalib -1;doband -1;outseq 0; cellsize 1.5; imsize 1024; uvwtfn ''; dotv -1; calcode '-cal'; robust 0.5; ngauss 4;wgauss 0,15,45,135; fgaus 2*1.12e-3 2*1.37e-3 2*1.86e-3 2*3.47e-3 $ fgaus 2sigma in all fields niter 1e6 $just to ensure we reach the Fgauss limits nbox 1 clbox 230.00 270.00 780.00 820.00 $enough to hold all the signal in every channel $its size should have been decided at step 6C bchan 80;echan 85;outn 'test1' imagrprm 0; imagrprm(10) 1; $multiplier of max image size to set beam size imagrprm(11) 0.2; $the alpha parameter, which steers MSCLEAN towards certain scale components getn DDO50_BCD.UVLSF Noise level: 1.10millyJy #### Look at the maps, see if there are any indicatives of calibration problems or imaging problems ########Monitor the AIPS_MSGRV for any warning messeages especiallly ones like : "SOMETHING IS GOING WRONG.ABANDON CLEAN" or "Clean has begun to diverge.Stopping". IMAGR is running too fast to be able to make a true statistics of these messages, that is why the easiest way to go is after running IMAGR, run a PRTMSG and write the messages in a text file where you can easily scroll through and even use a query-replace to replace the text of the offending messages with more obvious lines of text to be able to see them faster. default prtmsg prtask 'IMAGR' $ the task for which you want the aips messages prtime 1 $ all IMAGRS younger than 1 day ouprint '/data6/dvicas/Imagrmsg $ the name of the file to write to docrt -1 prtmsg &prtmsg is a verb not a task C. If satisfied with the above than put the whole cube through this imaging recipe executed on 14 September 2009 DEFAULT IMAGR sources '',''; docalib -1;doband -1;outseq 0; outname 'ddo63'; cellsize 1.5; imsize 1024; uvwtfn ''; dotv -1; calcode '-cal'; robust 0.5; ngauss 4;wgauss 0,15,45,135; fgaus 2*1.12e-3 2*1.37e-3 2*1.86e-3 2*3.47e-3 $fgaus 2sigma in all fields niter 1e6 $just to ensure we reach the Fgauss limits nbox 1 clbox 230.00 270.00 780.00 820.00 imagrprm 0; imagrprm(10) 1; $multiplier of max image size to set beam size imagrprm(11) 0.2; $the alpha parameter, which steers MSCLEAN towards certain scale components bchan 10;echan 117; getn *.UVLSF ###Some close by galaxies might need a 2048 imsize in IMAGR;this necessity will become obvious when looking at the D array data. #### Look at the maps, see if there are any indicatives of calibration problems or imaging problems ########Monitor the AIPS_MSGRV for any warning messeages especiallly ones like : "SOMETHING IS GOING WRONG.ABANDON CLEAN" or "Clean has begun to diverge.Stopping". IMAGR is running too fast to be able to make a true statistics of these messages, that is why the easiest way to go is after running IMAGR, run a PRTMSG and write the messages in a text file where you can easily scroll through and even use a query-replace to replace the text of the offending messages with more obvious lines of text to be able to see them faster.See above, at step 7B for how to set PRTMSG. ###########Limit your cleaning if your science project allows it to the channels with line emission. In this sense worry if you see the above mentioned offending messages in line emission channels. Also it is possible that IMAGR scoops in one field, shoots out the message, gets out of the major cycle, restores components in all fields and by doing so also corrects the negativity of the problematic field.In the message file, where you see IMAGR after having given the warning message, return to that same field it means that MSCLEAN was able to correct itself. The big worry comes in when MSCLEAN stops cleaning alltogether, especially when that happens in a line emission channel. ##################Report any galaxies that do not comply to the above set of parameters.When you find that cleaning leaves behind a negative bowl, or when you find repeated offending messages with no indication of MSCLEAN correcting itself, let Elias or Dana know.Thanks! Computing the noise levels for the natural weigthing setting: DEFAULT IMAGR sources '',''; docalib -1;doband -1;outseq 0; cellsize 1.5; imsize 1024; uvwtfn ''; dotv -1; calcode '-cal'; robust 0.5; ngauss 4;wgauss 0,15,45,135; fgaus 0 $ no fgauss levels are necessary as we are not cleaning niter 0 $no cleaning, we just want to quantify the rms noise nbox 1 clbox 230.00 270.00 780.00 820.00 $enough to hold all the signal in every channel $its size should have been decided at step 6C bchan 20;echan 25; $select one or more line free channels outn 'noiseNA' imagrprm 0; imagrprm(10) 1; $multiplier of max image size to set beam size imagrprm(11) 0.2; $the alpha parameter, which steers MSCLEAN towards certain scale components uvwtfn 'na' The rms noise measured in a line free channel is: Field 1(5asec resolution): 1.02 mJy Field 2(15 asec resolution):1.39 mjy Field 3(45 asec resolution):2.06 mJy Field 4(135 asec resolution):4.02 mJy Making a natural weighted data cube: DEFAULT IMAGR sources '',''; docalib -1;doband -1;outseq 0; outname 'ddo63NA'; cellsize 1.5; imsize 1024; uvwtfn ''; dotv -1; calcode '-cal'; robust 0.5; ngauss 4;wgauss 0,15,45,135; fgaus 2.5*1.02e-3 2.5*1.39e-3 2.5*2.06e-3 2.5*4.02e-3 $fgaus 2sigma in all fields niter 1e6 $just to ensure we reach the Fgauss limits nbox 1 clbox 230.00 270.00 780.00 820.00 imagrprm 0; imagrprm(10) 1; $multiplier of max image size to set beam size imagrprm(11) 0.2; $the alpha parameter, which steers MSCLEAN towards certain scale components uvwtfn 'NA' $this will override the robust setting bchan 10;echan 117; getn *.UVLIN 8. Convolution and Blanking executed on 15 November 2009 A. Convolution DEFAULT CONVL blc 0; trc 0; outname ''; opcode ''; bmaj 25; bmin 25 outclass 'CVL25' getn *NA.ICL001 ###We are going to use the NAtural weighted cube to create the master blanking cube. ### Get rms in convolved cube: 1.52e-3 B. Blanking B.1 Making contour plots to identify the true line from the noise. DEFAULT KNTR docont 1; dogrey -1;dovect -1; ny 3; ltype 6; clev 0.001; levs 2.5*1.52, 3*1.52,5*1.52, 10*1.52, 20*1.52, 40*1.52, 80*1.52 $the lowest level is at 2.5sigma; $always between 2-2.5sigma); dotv 1; pixra -2*0.00152, 8*0.00152 $ pixrange=(-2sigma to +8sigma); docircle -1; blc 200.00 200.00 $ I used the same size as the window in IMAGR trc 800.00 800.00 getn *NA.CVL25 to get all interesting channels into PL files: for i=1 to 8;dotv -1; blc(3)= 25+(i-1)*9;trc(3)=24+i*9;go kntr;wait kntr; end to print all created PL files for i=1 to 8; plver =i; print i; go lwpla; wait lwpla; end B.2 Blank the cube automatically DEFAULT BLANK opcode 'SELC'; dparm 1, 0, 10000, 2.5*1.52e-3, 0 outclass 'CVL_BL'; trc 0; blc 0; bchan 0; echan 0 getn *NA.CVL25 B.3 Blank cube by hand - output is the master cube DEFAULT BLANK opcode 'TVCU'; doinvers -1; outclass 'master' getn *NA.CVL_BL B.2.3 use the master cube to blank the full resolution cube and the robust=0.5 cube DEFAULT BLANK opcode 'IN2C';outclass 'LMV'; getn *NA.ICL001 $the full resolution cube, the one created at step 7B get2n *.MASTER DEFAULT BLANK opcode 'IN2C';outclass 'LMV'; getn *.ICL001 $the full resolution cube, the one created at step 7B get2n *.MASTER ### It blanks the full resolution cube using the MASTER cube as a blanking model. ON THE ROBUST CUBE 9. Transposing the cube executed on 15 November 2009 DEFAULT TRANS outclass ''; blc 0; trc 0; transcod '312' 10. Switching the header from frequency description to spectral-line velocity description getn *. TRANS ALTSWCH 11. Final products executed on 15 November 2009 A. Moment maps: DEFAULT XMOM flux -10000; icut -10000; blc 0; trc 0 getn *.TRANS ###Note: The Primary beam correction(PBCOR) has not been applied. Something to think about would be which final products we want and which ones among those should be primary beam corrected#### 12. Primary Beam Corrections ***Corrects an image for the primary beam attenuation of the 25-meter antennas used at the VLA. altsw $PBCOR needs the FREQ axis rather than the velocity one $ use this verb to switch between the two DEFAULT PBCOR doinvers -1; coord 0; bparm 0; outclass 'X0_PBC' REMARK: If one wants to take a spectrum and needs the correct value of the flux in that spectrum, than the whole cube should be primary beam corrected. For more details contact Elias or Dana. ON THE NATURAL CUBE 9. Transposing the cube executed on 15 November 2009 DEFAULT TRANS outclass ''; blc 0; trc 0; transcod '312' getn *NA.LMV 10. Switching the header from frequency description to spectral-line velocity description getn *. TRANS ALTSWCH 11. Final products executed on 15 November 2009 A. Moment maps: DEFAULT XMOM flux -10000; icut -10000; blc 0; trc 0 getn *.TRANS ###Note: The Primary beam correction(PBCOR) has not been applied. Something to think about would be which final products we want and which ones among those should be primary beam corrected#### 12. Primary Beam Corrections ***Corrects an image for the primary beam attenuation of the 25-meter antennas used at the VLA. altsw $PBCOR needs the FREQ axis rather than the velocity one $ use this verb to switch between the two DEFAULT PBCOR doinvers -1; coord 0; bparm 0; outclass 'X0_PBC' REMARK: If one wants to take a spectrum and needs the correct value of the flux in that spectrum, than the whole cube should be primary beam corrected. For more details contact Elias or Dana. 13. Replacing blanks with 0 DEFAULT REMAG pixval 0; blc 0; trc 0; outclass 'X0_P_R' getn *.X0_PBC 14. Convolutions DEFAULT CONVL bmaj 10; bmin 10; blc 0; trc 0; opcode ''; outclass 'CVL10'; doblank 0; factor 0; outse 0; outname '' getn *.ICL001 DEFAULT BLANK opcode 'IN2C';outclass 'LMV'; getn *.CVL10 get2n *.MASTER ON THE CONVOLVED CUBE 9. Transposing the cube executed on 20 January 2010 DEFAULT TRANS outclass ''; blc 0; trc 0; transcod '312' 10. Switching the header from frequency description to spectral-line velocity description getn *. TRANS ALTSWCH 11. Final products executed on 20 January 2010 A. Moment maps: DEFAULT XMOM flux -10000; icut -10000; blc 0; trc 0 getn *.TRANS ###Note: The Primary beam correction(PBCOR) has not been applied. Something to think about would be which final products we want and which ones among those should be primary beam corrected#### 12. Primary Beam Corrections ***Corrects an image for the primary beam attenuation of the 25-meter antennas used at the VLA. altsw $PBCOR needs the FREQ axis rather than the velocity one $ use this verb to switch between the two DEFAULT PBCOR doinvers -1; coord 0; bparm 0; outclass 'X0_PBC' getn *.XMOM0 REMARK: If one wants to take a spectrum and needs the correct value of the flux in that spectrum, than the whole cube should be primary beam corrected. For more details contact Elias or Dana.