Extragalactic Formaldehyde VLA Data Reduction Summary


TIP Last Modified: JeffMangum - 08 February 2016

NOTE: AS OF 2016-02-08 ALL OF THESE DATA HAVE BEEN REDUCED

Archive Data Lookup Table

TIP NOTE: All archive data in galaxy-named directories at /.lustre/naasc/jmangum

Last Update: 2015-10-22

Galaxy 1(10)-1(11) SB 2(11)-2(12) SB
NGC253
9248494, 25319659
4982259, 30036798
NGC660
14663953
14661238, 16222241, 16222645
Maffei2
14664666
16036009, 16036408, 16036807
IC342
8142281
14501245, 14744397
NGC2146
9249059
14500590, 16223095, 16223498
NGC2903
8140024
16217913
M82
7273603
14502539, 16037206, 16037605
NGC3079
8139680, 25319655, 25539887, 29880198
4982247
NGC3628
8138765
 
IC860
8139336
16217069
M83
9246157
4982251
IR15107
8140712
14499961
Arp220
8140368
14498339
NGC6946
8145669
5344183

Final C- and Ku-Band Integrated Intensity and Ratio Images for all Galaxies

Integrated ratios:
  • /.lustre/naasc/jmangum/rsmullen/Final_Images/NGC253.ratio.C_Ku.image.clip_2sig.new.collapse.adjusted
  • /.lustre/naasc/jmangum/rsmullen/Final_Images/IC342.ratio.C_Ku.image.clip_2sig.collapse.adjusted
  • /.lustre/naasc/jmangum/rsmullen/Final_Images/M83.ratio.C_Ku.image.clip_2sig.collapse.adjusted
  • /.lustre/naasc/jmangum/rsmullen/Final_Images/NGC6946.ratio.C_Ku.image.clip_2sig.collapse.adjusted

Ratio cubes:
  • /.lustre/naasc/jmangum/rsmullen/Final_Images/NGC253.ratio.C_Ku.image.clip_2sig.new
  • /.lustre/naasc/jmangum/rsmullen/Final_Images/IC342.ratio.C_Ku.image.clip_2sig
  • /.lustre/naasc/jmangum/rsmullen/Final_Images/M83.ratio.C_Ku.image.clip_2sig
  • /.lustre/naasc/jmangum/rsmullen/Final_Images/NGC3079.ratio.C_Ku.image.clip_2sig
  • /.lustre/naasc/jmangum/rsmullen/Final_Images/NGC6946.ratio.C_Ku.image.clip_2sig

All the files for the C- and Ku-band images can be found in the /.lustre/naasc/jmangum/rsmullen/Final_Images directory.

-- JeffMangum - 2014-04-03

NGC253

Reduced Data Summary
 
 
 
 
 
Project Array Band SB Duration (hrs) Reduction Directory
12A-067
C
C
9248494
1.5
/lustre/naasc/jmangum/rsmullen/NGC253/12A067-C-C
11B-026
DnC
Ku
4982259
2.5
/lustre/naasc/jmangum/rsmullen/NGC253/11B26-Ku-DnC
13B-113
BnA
C
25319659
2.0
/lustre/naasc/jmangum/NGC253/13B113-C-BnA
14B-063
CnB
Ku
30036798
1.5
/lustre/naasc/jmangum/NGC253/14B063-Ku-CnB

H2CO 1(10)-1(11) C-array: NGC 253 was observed at 4.829660 GHz on 19 May 2012 using the CnB configuration of the EVLA. The target was observed for a total of 3395 seconds with five second integrations. The data, having 16 spectral windows with 128 channels apiece, were edited and calibrated following the standards EVLA procedures and using CASA. We initially had 27 antennas, and none were fully edited out during the calibration. We used the CLEAN algorithm to create both a continuum image and a spectral line cube. Once there was confirmation of signal, we recleaned the C band cube in velocity space to match the Ku band data. The resulting cube had 96 channels, beginning at a velocity of 13.74 km/s with a channel spacing of 5.2 km/s and a restoring beam of 6.3 square arcseconds. Again, we clipped the matched spectral line cube to 2 sigma and created an integrated intensity image. After we had both of our spectral line cubes and integrated intensity images cleaned to match each other and clipped, we took the ratio of the H_2CO 1(10)-1(11) to 2(11)-2(12) (5 GHz to 14.5 GHz) cubes and integrated intensities. This gave us both a ratio cube for NGC 253 and a ratio of the integrated intensities, clipped at 2 sigma. See NGC253CbandCarray.log for reduction and analysis notes.

H2CO 2(11)-2(12) DnC: NGC 253 was observed at 14.488479 GHz on 20-21 January 2012 using the DnC configuration of the Extended Very Large Array (EVLA) of the NRAO. We observed a total 6420 seconds on our target source using five second integrations. The data, having 16 spectral windows with 128 channels each, were edited and calibrated following the standards EVLA procedures and using the Common Astronomy Software Application (CASA) developed by the NRAO. We initially had 18 functioning antennas; these observations were taken while Ku band receivers were still being installed on the EVLA antennas. Over the course of our calibration, we had to flag out one antenna due to excessive noisiness. After finishing calibrations, we used the CLEAN algorithm to clean the noise level in both our continuum image and spectral line cube to 0.5 mJy. This source showed both strong continuum emission and strong absorption. We then recleaned the spectral line to match our C band image dimensions, using a start velocity of 13km/s, a channel spacing of 5.2km/s, and a resoring beam of 6.3 square arcseconds. Our resulting cube had 96 channels and an average rms of 0.4 mJy. We then clipped our cube at 1.5, 2, and 3 sigma, and decided that the 2 sigma clip provided the best representation of our galaxy. We used the imcollapse function to sum the channels with signal to create an integrated intensity map clipped at 2 sigma. See NGC253KubandDnCarray.log for reduction and analysis notes.

Synopsis for CnB-band C-array and Ku-band DnC-array: NGC 253 showed strong absorption against the background continuum in both C band and Ku band. We are able to see the absorption in both bands propagate southwest across the image (from the upper left to the lower right) as the velocity increases. This motion is consistent with the orientation of the galaxy. Please refer to Table 1 to see our measurements of the peak absorption. Because of the strong formaldehyde signature, we were able to easily take the ratio of 4.83 GHz to 14.48 GHz to determine the spacial density across the galaxy as a function of frequency. Our measured ratios are between ~0.2 and ~1.2. Using an LVG model from Mangum et al. (2011), we can estimate the density of H2 to be between 10^(5.3) and 10^(5.6) cm^(-3).

NGC660

Reduced Data Summary
 
 
 
 
 
Project Array Band SB Duration (hrs) Reduction Directory
13A-178
C
C
14663953
4.75
/lustre/naasc/jmangum/NGC660/CBand
13A-178
D
Ku
16222645
2.0
/lustre/naasc/jmangum/NGC660/KuBand
13A-178
D
Ku
14661238
2.0
/lustre/naasc/jmangum/NGC660/KuBand
13A-178
D
Ku
16222241
1.5
/lustre/naasc/jmangum/NGC660/KuBand

H2CO 1(10)-1(11) C-array: Used VLA pipeline to process single MS in this data set. Selfcaled to effect factor of 10 improvement in RMS. Imaging produced a nice image cube with absorption at the same velocities as seen in our GBT measurements. Intensities look about right. Absorption is roughly beam-sized, but with some small position shifting as a function of velocity. See what appears to be broad emission superimposed on narrower absorption. Should investigate this further!

H2CO 2(11)-2(12) D-array: Used VLA pipeline to process all three MS's in this data set. Selfcaled to effect factor of 13 to 20 improvement in RMS for each of the three MSs. Imaging produced a nice image cube with absorption at the same velocities as seen in our GBT measurements. Absorption is roughly beam-sized, but with some small position shifting as a function of velocity. Rough position of absorption is RA(J2000) = 01:43:02.381, Dec(J2000) = +13:38:44.341.

Maffei2

Reduced Data Summary
 
 
 
 
 
Project Array Band SB Duration (hrs) Reduction Directory
13A-178
C
C
14664666
2.75
/lustre/cv/jmangum/Maffei2/13A178CC
13A-178
D
Ku
16036009
1.5
/lustre/cv/jmangum/Maffei2/13A178KuD-1
13A-178
D
Ku
16036408
2.0
/lustre/cv/jmangum/Maffei2/13A178KuD-2
13A-178
D
Ku
16036807
2.0
/lustre/cv/jmangum/Maffei2/13A178KuD-3

H2CO 1(10)-1(11) C-array: Used VLA pipeline to process single MS in this data set. Selfcaled to effect factor of 2 improvement in RMS. Imaging produced a nice image cube with absorption at the same velocities as seen in our GBT measurements. Intensities look about right (though need to do further analysis to verify). Absorption is extremely weak

H2CO 2(11)-2(12) D-array: Used VLA pipeline to process all three MS's in this data set. Selfcaled to effect factor of about 4 improvement in RMS for each of the three MSs. Imaging produced a nice image cube with absorption at the same velocities as seen in our GBT measurements. Absorption is weak.

IC 342

Reduced Data Summary
 
 
 
 
 
Project Array Band SB Duration (hrs) Reduction Directory
12A-067
C
C
8142281
1.5
/.lustre/naasc/jmangum/rsmullen/NGC253/CI3128
11B-026
D
Ku
4982255
2.5
/.lustre/naasc/jmangum/rsmullen/NGC253/CH3945 (FOOBAR...DO NOT USE)
13A-178
D
Ku
14501245
1.3
/lustre/cv/jmangum/IC342/13A178KuD-1
13A-178
D
Ku
14744397
2.0
/lustre/cv/jmangum/IC342/13A178KuD-2

H2CO 1(10)-1(11): IC 342 was observed at a rest frequency of 4.829660 GHz on 15 February 2012 using the C configuration of the EVLA. We observed 3510 seconds on target using five second integrations. The data, arranged in 16 spectral windows with 128 channels per spectral window, were edited and calibrated following the standard EVLA procedures and using CASA. We started with 27 antennas flagged one during calibration. Post-calibration, we used the CLEAN algorithm to clean our continuum image and spectral line cube to an average rms of under 0.72 mJy. Neither the spectral line cube nor the integrated intensity showed any apparent signal.

H2CO 2(11)-2(12): IC342 was observed at 14.488479 GHz on 26 November 2011 using the D configuration of the EVLA. This object was intended to be observed for a total of 6180 seconds with 5 seconds integrations; however, the EVLA was experiencing problems with on-line time averaging greater than one second during the period of our observation. Therefore, we have only one-fifth the data we expected. The data were arranged in 16 spectral windows with 128 channels each and were edited and calibrated following the standard EVLA procedures and using CASA. We began with 17 antennas and removed one from our final calibration. Using the CLEAN algorithm, we attempted to clean the average rms noise in our continuum image and spectral line cube to under 0.26 mJy, but because of the lack of data, we were able to clean the images to about 0.75 mJy. Neither the spectral line cube nor the integrated intensity (integrated over the FWZI CO linewidth) showed any apparent signal. NOTE: This is from the 11B data only, which is not very useful.

Synopsis: IC 342 showed strong continuum emission, but no H2CO emission or absorption in both the spectral line cube nor the integrated intensity. Therefore, our ratio can only give us a lower bound on the ratio, or an upper limit on the density.

NGC2146

Reduced Data Summary
 
 
 
 
 
Project Array Band SB Duration (hrs) Reduction Directory
12A-067
CnB
C
9249059
3.5
/lustre/cv/jmangum/NGC2146/12A067CCnB
13A-178
DnC
Ku
14500590
2.0
/lustre/cv/jmangum/NGC2146/13A178KuDnC-1
13A-178
DnC
Ku
16223095
2.0
/lustre/cv/jmangum/NGC2146/13A178KuDnC-2
13A-178
DnC
Ku
16223498
2.0
/lustre/cv/jmangum/NGC2146/13A178KuDnC-3

NGC2903

Reduced Data Summary
 
 
 
 
 
Project Array Band SB Duration (hrs) Reduction Directory
12A-067
C
C
8140024
3.5
/lustre/cv/jmangum/NGC2903/12A067CC
13A-178
D
Ku
16217913
2.0
/lustre/cv/jmangum/NGC2903/13A178KuD

M82

Reduced Data Summary
 
 
 
 
 
Project Array Band SB Duration (hrs) Reduction Directory
12A-067
C
C
7273603
1.5
/lustre/cv/jmangum/nkern/M82/M82C
 
 
 
 
 
/lustre/naasc/jmangum/M82/12A067-C-C (includes selfcal)
13A-178
D
Ku
14502539
2.0
/lustre/cv/jmangum/nkern/M82/M82Ku
 
 
 
 
 
/lustre/naasc/jmangum/M82/13A178-Ku-D/20130213 (includes selfcal)
13A-178
D
Ku
16037605
1.5
/lustre/cv/jmangum/nkern/M82/M82Ku
 
 
 
 
 
/lustre/naasc/jmangum/M82/13A178-Ku-D/20130214 (includes selfcal)
13A-178
D
Ku
16037206
2.0
/lustre/cv/jmangum/nkern/M82/M82Ku
 
 
 
 
 
/lustre/naasc/jmangum/M82/13A178-Ku-D/20130301 (includes selfcal)

See /lustre/naasc/jmangum/M82/13A178-Ku-D for final image cubes. Use selfcal analysis.

NGC3079

Reduced Data Summary
 
 
 
 
 
Project Array Band SB Duration (hrs) Reduction Directory
12A-067
C
C
8139680
4.0
/.lustre/naasc/jmangum/rsmullen/NGC3079/CI3128
11B-026
D
Ku
4982247
1.5
/.lustre/naasc/jmangum/rsmullen/NGC3079/CH3945
13B-113
B
C
25319655
5.0
/lustre/naasc/jmangum/NGC3079/13B113-C-B-20130928
13B-113
B
C
25539887
4.0
/lustre/naasc/jmangum/NGC3079/13B113-C-B
14B-063
C
Ku
29880198(1)
4.0
/lustre/naasc/jmangum/NGC3079/14B063-Ku-C
14B-063
C
Ku
29880198(2)
4.0
/lustre/naasc/jmangum/NGC3079/14B063-Ku-C

H2CO 1(10)-1(11): NGC 3079 was observed at a rest frequency of 4.829660 GHz on 07 March 2012 using the C configuration of the EVLA. We observed 10530 seconds on target using five second integrations. The data, arranged in 16 spectral windows with 128 channels apiece, were edited and calibrated following the standard EVLA procedures and using CASA. We started with 27 antennas and did not need to remove any over the course of the calibration. Post-calibration, we used the CLEAN algorithm to clean our continuum image and spectral line cube to an average rms of under 0.4 mJy. We again observed both emission and obsorption over different lines We recleaned in velocity space with 68 channels beginning at 808 km/s, a channel spacing of 10.5 km/s, and a restoring beam of 12.4 square arcseconds. We created an integrated intensity image over the absorption channels and then clipped both the integrated intensity image and the spectral line cube at 2 sigma. After we had both of our spectral line cubes and integrated intensity images cleaned to match each other and clipped, we took the ratio of the H_2CO 1(10,11) to 2(11,12) (5 GHz to 14.5 GHz) cubes and integrated intensities. This gave us both a ratio cube for NGC 3079 and a ratio of the integrated intensities, clipped at 2 sigma.

H2CO 2(11)-2(12): NGC 3079 was observed at 14.488479 GHz on 12 December 2011 using the D configuration of the EVLA. This was a re-observation of this target; the EVLA was experiencing problems with on-line time averaging greater than 1.0 second during the period of our first observation. With the new set of data, we had a total time of 2770 seconds on target with a read out every five seconds. The data were arranged in 16 spectral windows with 128 channels each and were edited and calibrated following the standard EVLA procedures and using CASA. We began with 16 antennas and did not have to fully remove any from our final calibration. Using the CLEAN algorithm, we brought the average rms noise in our continuum image and spectral line cube to under 0.3 mJy. The spectral line cube showed both emission and absorption. After confirming signal in the C band cube, we recleaned the Ku band image to match the C band data, using a start velocity of 808.8 km/s, a channel spacing of 10.5 km/s, and a restoring beam of 12.4 square arcseconds. Our resulting cube has 68 channels and an average rms of 0.13 mJy. The absorption in our smoothed cube is smaller than our beam and is therefore unresolved. We created an integrated intensity image using imcollapse in CASA. This may not be the best representation of the galaxy structure because of the combined emission and absorption observed. Finally, we then clipped both our spectral line cube and integrated intensities at 2 sigma.

Synopsis: This galaxy is the odd one in the bunch. It is the only high temperature galaxy (>270K), and it is the only one to show both emission and absorption. The 14.48 GHz data show only absorption, while the 4.83 GHz data show primarily emission with a narrow, strong peak of absorption in the middle. This is mostly consistent with the GBT spectrum, which showed some emission and a strong absorption peak. Our ratio calculations supported our initial observations: the ratio is negative everywhere but where we see the absorption peak in the C band spectral line cube. Our values for the ratio put us into the “valley” where absorption and emission join. We found ratios between -1.5 and +1.5, which is a hydrogen density between 10^(4.85) and 10^(5.05) on a LVG model that is at a temperature of 200K.

NGC3628

Reduced Data Summary
 
 
 
 
 
Project Array Band SB Duration (hrs) Reduction Directory
12A-067
C
C
8138765
1.5
/lustre/cv/jmangum/NGC3628/12A067CC

IC860

Reduced Data Summary
 
 
 
 
 
Project Array Band SB Duration (hrs) Reduction Directory
12A-067
C
C
8139336
1.5
/lustre/naasc/jmangum/IC860/12A067CC
13A-178
D
Ku
16217069
1.5
/lustre/naasc/jmangum/IC860/13A178KuD

H2CO 1(10)-1(11): Detected in emission, as expected. See IC860H2COJ1J2ReductionReport.pdf for details.

H2CO 2(11)-2(12): Detected in absorption, as expected. See IC860H2COJ1J2ReductionReport.pdf for details.

M83

Reduced Data Summary
 
 
 
 
 
Project Array Band SB Duration (hrs) Reduction Directory
12A-067
CnB
C
9246157
1.5
/lustre/naasc/jmangum/rsmullen/M83/PN5841
11B-026
DnC
Ku
4982251
1.5
/lustre/naasc/jmangum/rsmullen/M83/CH3945

H2CO 1(10)-1(11): M83 was observed at a rest frequency of 4.829660 GHz on 03 May 2012 using the C configuration of the EVLA. This galaxy was observed for a total of 3395 seconds with five second integrations. The data, in 16 spectral windows with 128 spectral windows apiece, were edited and calibrated following the standard EVLA procedures and using CASA. We began with 27 antennas and did not have to entirely flag any antennas over the course of the calibrations. We utilized the CLEAN algorithm to clean the continuum emission and the C band spectral line cube to an rms noise of 0.75 mJy. We noticed the same striping pattern in our C band images as we did in the Ku. Our spectral line cube also did not show any compact features. Our lack of detection of compact features in M83 leads us to believe that the absorption observed in our single-pointing measurements with the Green Bank Telescope of the NRAO (Mangum, et al. 2012, in preperation) are sensitive to more diffuse emission in the galaxy.

H2CO 2(11)-2(12): M83 was observed at 14.488479 GHz on 06 January 2012 using the DnC configuration of the EVLA. This object was observed for a total of 3215 seconds with 5 seconds integrations. The data, arranged into 16 spectral windows with 128 spectral windows apiece, were edited and calibrated following the standard EVLA procedures and using CASA. We began with sixteen antennas but had to edit out four over the course of the reduction. Once finished calibrating, we used the CLEAN algorithm to get the rms noise in the continuum image and the spectral line cube under 0.65 mJy. We observed what can be described as wide striping in the image. There were no apparent calibration errors that we could find that would account for the pattern, so we suspect that there is an outside source contaminating our field, although none could be found when looked for in a large, low resolution image. We also tried cleaning the Ku band cube using only the higher U-V wavelengths (above 12 kilolambda), which is the region less sensitive to the diffuse emission that might account for the observed banding. While M83 showed a strong continuum emission, we were not able to find any apparent compact absorption in our spectral line cube.

Synopsis: We were able to see strong continuum emission in both bands of M 83, although no absorption or emission in the spectral line cube. Therefore, our ratio can only give us a lower bound on the ratio, or an upper limit on the density. For M 83, our ratios were between -4 and +4, which gives us a density of < 10^(5.6) cm^(-3).

IR15107

Reduced Data Summary
 
 
 
 
 
Project Array Band SB Duration (hrs) Reduction Directory
12A-067
C
C
8140712
1.5
/lustre/naasc/jmangum/IR15107/13A178-Ku-D
13A-178
D
Ku
14499961
5.25
/lustre/naasc/jmangum/IR15107/13A178-Ku-D

Arp220

Reduced Data Summary
 
 
 
 
 
Project Array Band SB Duration (hrs) Reduction Directory
12A-067
C
C
8140368
1.5
/.lustre/naasc/nkern/Arp220/Arp220C
 
 
 
 
 
/lustre/naasc/jmangum/Arp220/12A067-C-C (includes selfcal)
13A-178
D
Ku
144983391
5.25
/.lustre/naasc/nkern/Arp220/Arp220Ku
 
 
 
 
 
/lustre/naasc/jmangum/Arp220/13A178-Ku-D (includes selfcal)

See /.lustre/naasc/nkern/Arp220/Arp220_Final_Data for final image cubes. Use selfcaled analysis in my directories for final analysis.

NGC 6946

Reduced Data Summary
 
 
 
 
 
Project Array Band SB Duration (hrs) Reduction Directory
12A-067
C
C
8145669
1.5
/lustre/naasc/jmangum/rsmullen/NGC6946/CI3128
11B-026
D
Ku
5344183
4.5
/lustre/naasc/jmangum/rsmullen/NGC6946/CH3945

H2CO 1(10)-1(11): NGC 6946 was observed at a rest frequency of 4.829660 GHz on 04 February 2012 using the C configuration of the EVLA. Our target was observed for a total of 3510 seconds using five second integrations. The data, arranged in 16 spectral windows with 128 spectral windows each, were edited and calibrated following the standard EVLA procedures and using CASA. We began with 26 antennas and flagged out two antennas over the course of the calibrations. We utilized the CLEAN algorithm to clean the continuum emission and the C band spectral line cube to an rms noise of under 0.72 mJy. Our spectral line cube and integrated intensity at this frequency also did not show any compact features.

H2CO 2(11)-2(12): NGC 6946 was observed at 14.488479 GHz on 25~26 November 2011 using the D configuration of the EVLA. This object was intended to be observed for a total of 12290 seconds with 5 seconds integrations; however, the EVLA was experiencing problems with on-line time averaging greater than 1.0 seconds during the period of our observation. Therefore, we have only one-fifth the data we expected. The data, arranged into 16 spectral windows with 128 spectral windows apiece, were edited and calibrated following the standard EVLA procedures and using CASA. We began with seventeen antennas and edited out one over the course of the reduction. When calibrated, we cleaned the measurement set with the CLEAN algorithm to lower the rms noise in the continuum image and the spectral line cube to under 0.6 mJy. The expected rms for a full set of data was 0.3 mJy. Our target showed a strong continuum emission, but we were not able to find any apparent compact absorption in our spectral line cube or an integrated intensity image of the cube.

Synopsis: There was strong continuum emission in NGC 6946, although we could not detect any signal in the spectral line cubes. There is a possible blip of absorption that shows in the integrated intensity, but not enough to call a detection. Therefore, our ratio can only give us a lower bound on the ratio, or an upper limit on the density. For NGC 6946, our ratios were between -3.5 and +3.5, which gives us a density of < 10^(5.6) cm^(-3).

-- JeffMangum - 2014-01-03
Topic revision: r30 - 2016-02-08, JeffMangum
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