M100 Band3 SingleDish 4.2.2
M100 Single Dish Data Reduction
Overview
This portion of the M100 Single Dish Data Reduction CASA Guide will cover the reduction of the Total Power (TP) array data into units of Kelvins on the antenna temperature (Ta*) scale and imaging. Converting this image to the Jansky scale (Jy/beam) to be combined with interferometric data is covered in the M100 Band3 Combine 4.1 section.
This guide is designed for CASA 4.1.0.
If you haven't downloaded the data, you can XXXXXXX and XXXXXX:
Once the download has finished, upack the file:
# In a terminal outside CASA
tar -xvzf XXXsingledish_datasetXXX_TBD.tgz
cd XXrelevant_directoryXXX
# Start CASA
casapy
Confirm your version of CASA
This guide has been written for CASA release 4.1.0. Please confirm your version before proceeding.
# In CASA
version = casadef.casa_version
print "You are using " + version
if (version < '4.1.0'):
print "YOUR VERSION OF CASA IS TOO OLD FOR THIS GUIDE."
print "PLEASE UPDATE IT BEFORE PROCEEDING."
else:
print "Your version of CASA is appropriate for this guide."
The data have already been converted to CASA Measurement Set (MS) format using the CASA task importasdm.
Initial Inspection, Sky subtraction, Tsys application
We will eventually concatenate the six datasets used here into one large dataset. However, we will keep them separate for now, as some of the steps to follow require individual datasets to be calibrated separately (namely, the sky/Tsys calibration and baseline subtraction). We therefore start by defining an array "basename" that includes the names of the six files in chronological order. This will simplify the following steps by allowing us to loop through the files using a simple for-loop in python. Remember that if you log out of CASA, you will have to re-issue this command. We will remind you of this in the relevant sections by repeating the command at the start.
# In CASA
basename=['uid___A002_X60b415_X39a','uid___A002_X60b415_X6f7','uid___A002_X6218fb_X264', 'uid___A002_X6218fb_X425','uid___A002_X6321c5_X3a7','uid___A002_X6321c5_X5ca']
The usual first step is then to get some basic information about the data. We do this using the task listobs, which will output a detailed summary of each dataset supplied.
# In CASA
for name in basename:
listobs(vis=name+'.ms')
Note that after cutting and pasting a for-loop you often have to press return several times to execute. The output will be sent to the CASA logger. You will have to scroll up to see the individual output for each of the six datasets. Here is an example of the most relevant output for the fifth file in the list.
Observation: ALMA
Data records: 16588 Total integration time = 1302.91 seconds
Observed from 12-May-2013/02:22:16.9 to 12-May-2013/02:43:59.8 (UTC)
ObservationID = 0 ArrayID = 0
Date Timerange (UTC) Scan FldId FieldName nRows nUnflRows SpwIds Average Interval(s) ScanIntent
12-May-2013/02:22:16.3 - 02:22:42.8 1 0 M100 900 0.00 [0, 1, 2, 3, 4, 5, 6, 7, 8] [1.15, 0.48, 0.48, 0.48, 0.48, 0.48, 0.48, 0.48, 0.48] CALIBRATE_ATMOSPHE
RE#ON_SOURCE,CALIBRATE_WVR#ON_SOURCE
02:23:24.3 - 02:25:11.4 2 0 M100 1524 0.00 [0, 9, 10, 11, 12, 13, 14, 15, 16] [1.15, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01] OBSERVE_TAR
GET#OFF_SOURCE,CALIBRATE_WVR#OFF_SOURCE
02:25:25.2 - 02:27:11.2 3 0 M100 1522 0.00 [0, 9, 10, 11, 12, 13, 14, 15, 16] [1.15, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01] OBSERVE_TAR
GET#OFF_SOURCE,CALIBRATE_WVR#OFF_SOURCE
02:27:25.1 - 02:29:11.0 4 0 M100 1522 0.00 [0, 9, 10, 11, 12, 13, 14, 15, 16] [1.15, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01] OBSERVE_TAR
GET#OFF_SOURCE,CALIBRATE_WVR#OFF_SOURCE
02:29:24.9 - 02:31:12.0 5 0 M100 1524 0.00 [0, 9, 10, 11, 12, 13, 14, 15, 16] [1.15, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01] OBSERVE_TAR
GET#OFF_SOURCE,CALIBRATE_WVR#OFF_SOURCE
02:31:25.8 - 02:33:11.8 6 0 M100 1522 0.00 [0, 9, 10, 11, 12, 13, 14, 15, 16] [1.15, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01] OBSERVE_TAR
GET#OFF_SOURCE,CALIBRATE_WVR#OFF_SOURCE
02:34:03.6 - 02:34:29.0 7 0 M100 900 0.00 [0, 1, 2, 3, 4, 5, 6, 7, 8] [1.15, 0.48, 0.48, 0.48, 0.48, 0.48, 0.48, 0.48, 0.48] CALIBRATE_ATMOSPHE
RE#ON_SOURCE,CALIBRATE_WVR#ON_SOURCE
02:34:42.8 - 02:36:30.0 8 0 M100 1524 0.00 [0, 9, 10, 11, 12, 13, 14, 15, 16] [1.15, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01] OBSERVE_TAR
GET#OFF_SOURCE,CALIBRATE_WVR#OFF_SOURCE
02:36:43.8 - 02:38:29.8 9 0 M100 1524 0.00 [0, 9, 10, 11, 12, 13, 14, 15, 16] [1.15, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01] OBSERVE_TAR
GET#OFF_SOURCE,CALIBRATE_WVR#OFF_SOURCE
02:38:43.6 - 02:40:30.7 10 0 M100 1524 0.00 [0, 9, 10, 11, 12, 13, 14, 15, 16] [1.15, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01] OBSERVE_TAR
GET#OFF_SOURCE,CALIBRATE_WVR#OFF_SOURCE
02:40:44.5 - 02:42:30.5 11 0 M100 1524 0.00 [0, 9, 10, 11, 12, 13, 14, 15, 16] [1.15, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01] OBSERVE_TAR
GET#OFF_SOURCE,CALIBRATE_WVR#OFF_SOURCE
02:42:44.4 - 02:44:00.4 12 0 M100 1078 0.00 [0, 9, 10, 11, 12, 13, 14, 15, 16] [1.15, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01] OBSERVE_TAR
GET#OFF_SOURCE,CALIBRATE_WVR#OFF_SOURCE
(nRows = Total number of rows per scan)
Fields: 1
ID Code Name RA Decl Epoch SrcId nRows nUnflRows
0 none M100 12:22:54.899040 +15.49.20.57200 J2000 0 16588 0.00
Spectral Windows: (17 unique spectral windows and 2 unique polarization setups)
SpwID Name #Chans Frame Ch1(MHz) ChanWid(kHz) TotBW(kHz) BBC Num Corrs
0 WVR#NOMINAL 4 TOPO 184550.000 1500000.000 7500000.0 0 XX
1 ALMA_RB_03#BB_1#SW-01#FULL_RES 128 TOPO 101942.187 -15625.000 2000000.0 1 XX YY
2 ALMA_RB_03#BB_1#SW-01#CH_AVG 1 TOPO 100926.562 1781250.000 1781250.0 1 XX YY
3 ALMA_RB_03#BB_2#SW-01#FULL_RES 128 TOPO 103757.337 -15625.000 2000000.0 2 XX YY
4 ALMA_RB_03#BB_2#SW-01#CH_AVG 1 TOPO 102741.712 1781250.000 1781250.0 2 XX YY
5 ALMA_RB_03#BB_3#SW-01#FULL_RES 128 TOPO 111814.962 15625.000 2000000.0 3 XX YY
6 ALMA_RB_03#BB_3#SW-01#CH_AVG 1 TOPO 112783.712 1781250.000 1781250.0 3 XX YY
7 ALMA_RB_03#BB_4#SW-01#FULL_RES 128 TOPO 113689.962 15625.000 2000000.0 4 XX YY
8 ALMA_RB_03#BB_4#SW-01#CH_AVG 1 TOPO 114658.712 1781250.000 1781250.0 4 XX YY
9 ALMA_RB_03#BB_1#SW-01#FULL_RES 4080 TOPO 101945.850 -488.281 1992187.5 1 XX YY
10 ALMA_RB_03#BB_1#SW-01#CH_AVG 1 TOPO 100949.756 1992187.500 1992187.5 1 XX YY
11 ALMA_RB_03#BB_2#SW-01#FULL_RES 4080 TOPO 103761.000 -488.281 1992187.5 2 XX YY
12 ALMA_RB_03#BB_2#SW-01#CH_AVG 1 TOPO 102764.906 1992187.500 1992187.5 2 XX YY
13 ALMA_RB_03#BB_3#SW-01#FULL_RES 4080 TOPO 111811.300 488.281 1992187.5 3 XX YY
14 ALMA_RB_03#BB_3#SW-01#CH_AVG 1 TOPO 112806.906 1992187.500 1992187.5 3 XX YY
15 ALMA_RB_03#BB_4#SW-01#FULL_RES 4080 TOPO 113686.300 488.281 1992187.5 4 XX YY
16 ALMA_RB_03#BB_4#SW-01#CH_AVG 1 TOPO 114681.906 1992187.500 1992187.5 4 XX YY
Sources: 19
ID Name SpwId RestFreq(MHz) SysVel(km/s)
0 M100 0 - -
0 M100 17 - -
0 M100 18 - -
0 M100 1 - -
0 M100 2 - -
0 M100 3 - -
0 M100 4 - -
0 M100 5 - -
0 M100 6 - -
0 M100 7 - -
0 M100 8 - -
0 M100 9 100950 0
0 M100 10 100950 0
0 M100 11 102794.1 0
0 M100 12 102794.1 0
0 M100 13 112794.1 0
0 M100 14 112794.1 0
0 M100 15 114669.1 0
0 M100 16 114669.1 0
Antennas: 2:
ID Name Station Diam. Long. Lat. Offset from array center (m) ITRF Geocentric coordinates (m)
East North Elevation x y z
0 PM01 T704 12.0 m -067.45.16.2 -22.53.22.1 42.8992 -520.1885 22.2159 2225113.044955 -5440122.820877 -2481517.728410
1 PM04 T703 12.0 m -067.45.16.2 -22.53.23.9 42.8809 -575.6904 21.7744 2225104.701420 -5440102.470120 -2481568.688227
