Sgr_B2N Band 5 Science Verification Data (An almost complete spectral scan of ALMA Band 5) This was observed using 13 tunings (SBs). Each tuning employed a single sideband with 4 adjacent spectral windows, and a final frequency resolution of 0.488 MHz. There are (in most cases) small gaps between tunings and spw. Each execution used 8 to 12 12-m antennas, on baselines up to 1.6 km and some also included 4 7-m antennas. As a result of the sparse uv coverage and variable number of antennas, the range of spatial scales sampled is incomplete and varies across the spectral scan. Sgr B2N contains very extended emission and a 'line forest' - there is not enough line-free continuum to make a combined continuum-only image, nor to subtract the continuum, using the information contained in these data alone. For these reasons, the map distribution and relative flux densities of different species is hard to compare quantitatively and you are warned to use care in interpreting large scale emission, since much of this may be missing in different ways from different data sets. Faint details are sensitive to masking during image cleaning and should be treated with caution. The target was a single pointing at Right Ascension, Declination = 17h47m20.00s -28d22m19.08s J2000. The observations covering the 183-GHz water line observed the target for 23.8 min and used J1700-2610 as the phase-reference source. All other tunings consisted of 1, 2 or 3 executions, each of about 2-3 min on the target. J1744-3116 was used as the phase-reference source. For these tunings, we harmonised the flux scale by fitting a first-order spectral index to all measurements of the flux density of J1924-2914. Standard ALMA data reduction procedures were used as far as possible. If necessary, a delay correction was performed, this will appear in the calibration script. A subset of the data has been imaged, with sample cubes made for each tuning. In each case, a stopping threshold of about 2*expected rms was set in CASA tclean for the short executions, i.e. this is the maximum sought clean component; the actual rms varies between thermal and ~2*thermal. **Please note that in some cases CASA task mstransform is used to convert the visibility data to constant velocity in the direction of Sgr B2, before imaging; in other cases this is done during imaging. The tuning containing 183 GHz is the only one where this step is required, in other cases it is optional. If mstransform has been run on the data prior to imaging, the calibrated data filename will contain "LSRK". Self-calibration was performed for the tuning containing 183 GHz only. Please also note that the line IDs are tentative and may include blending. --------------------------------------------------------------- Publications making use of these data must include the following statement in the acknowledgement: "This paper makes use of the following ALMA data: ADS/JAO.ALMA#2011.0.00019.SV. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada) and NSC and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ." In addition, publications from NA authors must include the standard NRAO acknowledgement: "The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc." ################################################################################### TO USE THE SCRIPTS INCLUDED IN THIS PACKAGE (1) Calibrating each ALMA raw data set (a) Put a rawdata dataset and the corresponding *calibration*py script into the same directory (b) In CASA 4.7 e.g. execfile('uid___A002_Xb79187_X29d.ms.scriptForCalibration_163.py') (c) Repeat for each rawdata set for that tuning, each time in a separate directory (2) To perform the flux equalisation/harmonisation step (a) Move all of the *ms.split.cal created for that tuning (one per rawdata set) into the same directory, with the scriptForFluxEqualization*py script (b) In CASA 4.7 e.g. execfile('scriptForFluxEqualization_163.py') The output file (e.g. X29d_Sgr_B2N.ms.LSRK_FluxEqual_163) can be used in the imaging script, or else this file is provided in the SV data release. (3) To perform the imaging (own masking) (a) Move the calibrated data file (e.g. X29d_Sgr_B2N.ms.LSRK_FluxEqual_163) into a directory with the imaging script The best results will be obtained by setting clean boxes around the strongest emission initially, and extending these as cleaning progresses. (b) In CASA 4.7 e.g. execfile('scriptForImaging_163.py') (4) To perform the imaging (using the masks provided) (a) The masks used in the observatory imaging are provided in the *ReferenceImages.tgz files (b) To perform the imaging for any tuning, move the calibrated data, the appropriate mask file (untar using tar -zxf and then rename the mask file) and the imaging script into the same directory (c) In the imaging script, edit the tclean command so that the name of the mask file to be picked up is defined e.g. add mask='maskname.mask' If it is not clear how to do this, please consult the internal CASA help by typing: help tclean (d) In CASA 4.7 execute the imaging script using e.g. execfile('scriptForImaging_171.py') ################################################################################### CONTENTS * Numbers in the suffix refer to frequency i.e. "_163" is 163 GHz * Precipitable water vapour conditions during the observations are given in parentheses ----- SgrB2_Band5_UncalibratedData_163.tgz * uid___A002_Xb79187_X29d (pwv <~1.3 mm) SgrB2_Band5_CalibratedData_163.tgz * X29d_Sgr_B2N.ms.LSRK_FluxEqual_163 SgrB2_Band5_Scripts_163.tgz * uid___A002_Xb79187_X29d.ms.scriptForCalibration_163.py * scriptForFluxEqualization_163.py * scriptForImaging_163.py SgrB2_Band5_ReferenceImages_163.tgz * SgrB2_163_spw0_520-643_163.753GHz_HC3N_cube.clean.pb.fits * SgrB2_163_spw0_520-643_163.753GHz_HC3N_cube.clean.mask.tgz * SgrB2_163_spw0_520-643_163.753GHz_HC3N_cube.clean.pbcorr.fits * SgrB2_163_spw3_1062-1196_166.169GHz_CH3OH_cube.clean.pb.fits * SgrB2_163_spw3_1062-1196_166.169GHz_CH3OH_cube.clean.mask.tgz * SgrB2_163_spw3_1062-1196_166.169GHz_CH3OH_cube.clean.pbcorr.fits ------ SgrB2_Band5_UncalibratedData_167.tgz * uid___A002_Xb79187_X332 (pwv <~1.3 mm) SgrB2_Band5_CalibratedData_167.tgz * X332_Sgr_B2N.ms.LSRK_FluxEqual_167 SgrB2_Band5_Scripts_167.tgz * uid___A002_Xb79187_X332.ms.scriptForCalibration_167.py * scriptForFluxEqualization_167.py * scriptForImaging_167.py SgrB2_Band5_ReferenceImages_167.tgz * SgrB2_167_spw0_1500-1620_166.899GHz_CH3OH_cube.clean.pb.fits * SgrB2_167_spw0_1500-1620_166.899GHz_CH3OH_cube.clean.mask.tgz * SgrB2_167_spw0_1500-1620_166.899GHz_CH3OH_cube.clean.pbcorr.fits ------ SgrB2_Band5_UncalibratedData_171.tgz * uid___A002_Xb79187_X391 (pwv <~1.3 mm) 10 minutes lapse between phase cal observation and science target observation due to high elevation (phase reasonably stable) SgrB2_Band5_CalibratedData_171.tgz * X391_Sgr_B2N.ms_FluxEqual_171 SgrB2_Band5_Scripts_171.tgz * uid___A002_Xb79187_X391.ms.scriptForCalibration_171.py * scriptForFluxEqualization_171.py * scriptForImaging_171.py SgrB2_Band5_ReferenceImages_171.tgz * SgrB2_171_spw2_54-184_HCO.clean.pb.fits * SgrB2_171_spw2_54-184_HCO.clean.mask.tgz * SgrB2_171_spw2_54-184_HCO.clean.pbcorr.fits ------ SgrB2_Band5_UncalibratedData_175.tgz * uid___A002_Xb79187_X18db (pwv <~1 mm) * uid___A002_Xb7c496_X320 (pwv 0.8~1 mm) SgrB2_Band5_CalibratedData_175.tgz * X18db_Sgr_B2N.ms_FluxEqual_175 * X320_Sgr_B2N.ms_FluxEqual_175 SgrB2_Band5_Scripts_175.tgz * uid___A002_Xb79187_X18db.ms.scriptForCalibration_175.py * uid___A002_Xb7c496_X320.ms.scriptForCalibration_175.py * scriptForFluxEqualization_175.py * scriptForImaging_175.py SgrB2_Band5_ReferenceImages_175.tgz * SgrB2_175_spw0.clean.pb.fits * SgrB2_175_spw0.clean.mask.tgz * SgrB2_175_spw0.clean.pbcorr.fits ------ SgrB2_Band5_UncalibratedData_179.tgz * uid___A002_Xb7a113_Xd6c (pwv 0.6~1 mm) * uid___A002_Xb7c496_X37d (pwv 0.8~1 mm) SgrB2_Band5_CalibratedData_179.tgz * Xd6c_Sgr_B2N.ms_FluxEqual_179 * X37d_Sgr_B2N.ms_FluxEqual_179 SgrB2_Band5_Scripts_179.tgz * uid___A002_Xb7a113_Xd6c.ms.scriptForCalibration_179.py * uid___A002_Xb7c496_X37d.ms.scriptForCalibration_179.py * scriptForFluxEqualization_179.py * scriptForImaging_179.py SgrB2_Band5_ReferenceImages_179.tgz * SgrB2_179_spw3_1150-1230_Methanol.clean.pb.fits * SgrB2_179_spw3_1150-1230_Methanol.clean.mask.tgz * SgrB2_179_spw3_1150-1230_Methanol.clean.pbcorr.fits ------ SgrB2_Band5_UncalibratedData_183.tgz * uid___A002_Xb7c496_X4ab (pwv 0.8~1 mm) rms 77 mJy/bm at 181.193 GHz; rms 160 mJy/bm at 183.314 GHz after self-calibration of this spectral window. This data set has better visibility plane coverage. For the spectral window covering the 183-GHz water line, the very bright maser was used for self-calibration and the solutions applied to the whole spectral window. SgrB2_Band5_CalibratedData_183.tgz * X4ab_Sgr_B2N.ms.LSRK_FluxEqual_concat_183 SgrB2_Band5_Scripts_183.tgz * uid___A002_Xb7c496_X4ab.ms.scriptForCalibration_183.py * scriptForFluxEqualization_183.py * scriptForImaging_183.py SgrB2_Band5_ReferenceImages_183.tgz * X4ab_SgrB2_spw1_1496.clean.pb.fits * X4ab_SgrB2_spw1_1496.clean.mask.tgz * X4ab_SgrB2_spw1_1496.clean.pbcorr.fits * X4ab_SgrB2_spw1_H2O.clean.pb.fits * X4ab_SgrB2_spw1_H2O.clean.mask.tgz * X4ab_SgrB2_spw1_H2O.clean.pbcorr.fits ------ SgrB2_Band5_UncalibratedData_187.tgz * uid___A002_Xb7a113_Xf3d pwv 0.6~1 mm * uid___A002_Xb7c496_X412 pwv 0.8~1 mm SgrB2_Band5_CalibratedData_187.tgz * Xf3d_Sgr_B2N.ms_FluxEqual_187 * X412_Sgr_B2N.ms_FluxEqual_187 SgrB2_Band5_Scripts_187.tgz * uid___A002_Xb7a113_Xf3d.ms.scriptForCalibration_187.py * uid___A002_Xb7c496_X412.ms.scriptForCalibration_187.py * scriptForFluxEqualization_187.py * scriptForImaging_187.py SgrB2_Band5_ReferenceImages_187.tgz * SgrB2_187_spw0_279-350_methanol.clean.pb.fits * SgrB2_187_spw0_279-350_methanol.clean.mask.tgz * SgrB2_187_spw0_279-350_methanol.clean.pbcorr.fits ------ SgrB2_Band5_UncalibratedData_191.tgz * uid___A002_Xb7a113_Xba1 (pwv 0.6~1 mm) * uid___A002_Xb7c496_X28b (pwv 0.8~1 mm) SgrB2_Band5_CalibratedData_191.tgz * Xba1_X28b_Sgr_B2N.ms.LSRK_FluxEqual_concat_191 SgrB2_Band5_Scripts_191.tgz * uid___A002_Xb7a113_Xba1.ms.scriptForCalibration_191.py * uid___A002_Xb7c496_X28b.ms.scriptForCalibration_191.py * scriptForFluxEqualization_191.py * scriptForImaging_191.py SgrB2_Band5_ReferenceImages_191.tgz * SgrB2_191_spw0_1159-1289_189.689GHz_CH3OH_cube.clean.pb.fits * SgrB2_191_spw0_1159-1289_189.689GHz_CH3OH_cube.clean.mask.tgz * SgrB2_191_spw0_1159-1289_189.689GHz_CH3OH_cube.clean.pbcorr.fits ------ SgrB2_Band5_UncalibratedData_195.tgz * uid___A002_Xb79187_X6d9 (pwv <~1.3 mm) SgrB2_Band5_CalibratedData_195.tgz * X6d9_Sgr_B2N.ms_FluxEqual_195 SgrB2_Band5_Scripts_195.tgz * uid___A002_Xb79187_X6d9.ms.scriptForCalibration_195.py * scriptForFluxEqualization_195.py * scriptForImaging_195.py SgrB2_Band5_ReferenceImages_195.tgz * SgrB2_X6d9_195_13CMeth.clean.pb.fits * SgrB2_X6d9_195_13CMeth.clean.mask.tgz * SgrB2_X6d9_195_13CMeth.clean.pbcorr.fits ------ SgrB2_Band5_UncalibratedData_199.tgz * uid___A002_Xb7a113_X5ce (pwv <~1.3 mm) SgrB2_Band5_CalibratedData_199.tgz * X5ce_Sgr_B2N.ms_FluxEqual_199 SgrB2_Band5_Scripts_199.tgz * uid___A002_Xb7a113_X5ce.ms.scriptForCalibration_199.py * scriptForFluxEqualization_199.py * scriptForImaging_199.py SgrB2_Band5_ReferenceImages_199.tgz * SgrB2_199_spw2_1260-1285_Methanol.clean.pb.fits * SgrB2_199_spw2_1260-1285_Methanol.clean.mask.tgz * SgrB2_199_spw2_1260-1285_Methanol.clean.pbcorr.fits ------ SgrB2_Band5_UncalibratedData_203.tgz * uid___A002_Xb79187_X11db (pwv <~1.3 mm) SgrB2_Band5_CalibratedData_203.tgz * X11db_Sgr_B2N.ms_FluxEqual_203 SgrB2_Band5_Scripts_203.tgz * uid___A002_Xb79187_X11db.ms.scriptForCalibration_203.py * scriptForFluxEqualization_203.py * scriptForImaging_203.py SgrB2_Band5_ReferenceImages_203.tgz * SgrB2_203_spw2_447-492_C3Hplus.clean.pb.fits * SgrB2_203_spw2_447-492_C3Hplus.clean.mask.tgz * SgrB2_203_spw2_447-492_C3Hplus.clean.pbcorr.fits ------ SgrB2_Band5_UncalibratedData_207.tgz * uid___A002_Xb79187_X14bd (pwv <~1.3 mm) * uid___A002_Xb7a113_X755 (pwv 0.8~1 mm) * uid___A002_Xb7c496_X22e (pwv <~1.3 mm) SgrB2_Band5_CalibratedData_207.tgz * X14bd_Sgr_B2N.ms_FluxEqual_207 * X755_Sgr_B2N.ms_FluxEqual_207 * X22e_Sgr_B2N.ms_FluxEqual_207 SgrB2_Band5_Scripts_207.tgz * uid___A002_Xb79187_X14bd.ms.scriptForCalibration_207.py * uid___A002_Xb7a113_X755.ms.scriptForCalibration_207.py * uid___A002_Xb7c496_X22e.ms.scriptForCalibration_207.py * scriptForFluxEqualization_207.py * scriptForImaging_207.py SgrB2_Band5_ReferenceImages_207.tgz * SgrB2_207_spw2_537-651_SO.clean.pb.fits * SgrB2_207_spw2_537-651_SO.clean.mask.tgz * SgrB2_207_spw2_537-651_SO.clean.pbcorr.fits ------ SgrB2_Band5_UncalibratedData_211.tgz * uid___A002_Xb7a113_X86f (pwv <~1.3 mm) * uid___A002_Xb7c496_Xc6 (pwv 0.8~1 mm) SgrB2_Band5_CalibratedData_211.tgz * X86f_Sgr_B2N.ms_FluxEqual_211 * Xc6_Sgr_B2N.ms_FluxEqual_211 SgrB2_Band5_Scripts_211.tgz * uid___A002_Xb7a113_X86f.ms.scriptForCalibration_211.py * uid___A002_Xb7c496_Xc6.ms.scriptForCalibration_211.py * scriptForFluxEqualization_211.py * scriptForImaging_211.py SgrB2_Band5_ReferenceImages_211.tgz * SgrB2_X86f_211_spw2.clean.pb.fits * SgrB2_X86f_211_spw2.clean.mask.tgz * SgrB2_X86f_211_spw2.clean.pbcorr.fits ------ SgrB2_completespectrum_30-100m.pdf SgrB2_183GHzwatertuning_30-100m.pdf The spectra included in these PDFs (full frequency range of the spectral scan and covering the water line only) are uvspectra with baselines 30-100m, which included the shortest baselines of the extended array. For creating the plot for the full frequency range, different tunings showed different levels of continuum, and so were artificially multiplied/divided to align tunings by eye. Note that the jumps in scale that were removed by doing this are mostly due to the fact that even with the same range of uv distances, the actual coverage varied according to the antennas present and, especially, according to the uv angle (since there are only a few minutes of data for each tuning, taken at different times of day).