# script to image individual lines # first split the channels where the line is, # and substract continuum before imaging # NOTE the images in the archive of the whole spws are of # lower spectral resolution and the continuum was not substracted! # selected the channels to split in plotms with the original spectral resolution split(vis = 'uid___A002_Xa0b40d_X3cb8_spw1.ms', outputvis = 'iras16293_CH3OH.ms', datacolumn = 'data', field = 'IRAS16293-2422', spw = '0:1200~1550') #---------------------------- # CH3OH (spw1) # CH3OH vt=0 7( 1, 7)- 6( 1, 6)++ @ 335.58200 GHz # plotms iras16293_CH3OH.ms in amp vs freq averaging time. # transform frame=LSRK rest Freq 335729 # visualize amp vs velocity ---> the source velocity ~3 km/s is visible # the line is between -10 km/s and ~18 km/s remember this for clean # plot amp vs channel to identify the continuum channels # substract continuum: uvcontsub(vis = 'iras16293_CH3OH.ms', field = 'IRAS16293-2422', fitspw = '0:10~40;125~140;220~240;300~340') # observed spectral velocity ~0.22 km/s # image width 0.25 km/s # start -10km/s # To cover 28 km/s with 0.25 resolution need 112 chans # expected sensitivity from Sensitivity calculator # dec -24:00:00 # Freq 335 GHz # Bandwidth 0.25 km/s # Integration time 14 min # sensitivity 8 mJy # # before the final cleaning, I did a dirty image to check the channel seleccion was okay! clean(vis = 'iras16293_CH3OH.ms.contsub', imagename = 'iras16293_CH3OH', field = 'IRAS16293-2422', spw = '0', mode = 'velocity', nchan = 112, # modify depending on spectral resolution start = '-10km/s', # modify depending on spectral resolution width = '0.25km/s', # see notas_project, obtained in obs is ~0.22km/s restfreq = '335582.00MHz', outframe = 'LSRK', interactive = T, #interactive = F, niter = 10000, #niter = 0, # dirty image threshold = '24mJy', # use 3x8mJy (measured in dirty image in clean channel) imsize = [300, 300], #imsize = [280, 280], cell = '0.1arcsec', weighting='briggs', robust=0.5) # To make it fast just two masks around the two bright sources, no added masks around # the residuals appearing later. # The threshold is reached after 500 iterations. # The rms measured is ~6-7 mJy.