Program Overview

Program Overview#

ALMA observed AB Aur in April, May and September 2022 under program ID 2021.1.00690.S (PI: R. Dong). Measurements were taken with the Band 6 receivers (Ediss et al. 2004) in array configurations C-3 (2 execution blocks) and C-6 (6 execution blocks), hereafter the “short-baseline” and “long-baseline” configurations, respectively. In total, the 8 execution blocks (EBs) reached an on-source integration time of 5.75 hours.

Observation Summary#

Details of the ALMA Band 6 observations. Footnote \(^b\) refers to step 2.

Long baseline data (C-6 configuration)#

Below are further details on the TM1 scheduling block, compiled from a combination of the weblog and the QA reports. Note that you can scroll through this table horizontally.

Execution Block	Session	QA0 ExecBlock Status	QA0 Status	QA0 Comment	QA0 Warnings	Exec Fraction	Band	Repr. Frequency (GHz, Sky)	Baselines (m)	Antennas (total)	Shadowing	PWV (mm)	PWV Octile	Tsys (OT, K)	Tsys (EB, K)	Start	End	Time on AB Aur (min)	Calibrators: Atmosphere	Calibrators: Bandpass	Calibrators: Flux	Calibrators: Phase	Calibrators: Pointing	Calibrators: WVR	Observe Check Source
uid___A002_Xfb8480_X6a5b	1	SUCCESS	Pass	Excellent conditions	N/A	1.5	6	220.392	15-2617	41	0.00%	0.24	<1	116.5	65.4	2022-07-17 14:07:17	2022-07-17 15:25:26	47.37	J0510+1800, AB_Aur	J0510+1800	J0510+1800	J0438+3004	J0510+1800	J0438+3004, J0510+1800, AB_Aur, J0435+2532	J0435+2532
uid___A002_Xfb8480_X178cb	2	SUCCESS	Pass	The atmosphere was unstable	Achieved angular resolution is outside the expected range. Observed: 0.13, requested: 0.14 - 0.22	1.16	6	220.392	15-2617	42	1.11%	1.49	4-5	116.5	99.8	2022-07-19 12:02:10	2022-07-19 13:21:27	47.37	J0510+1800, AB_Aur	J0510+1800	J0510+1800	J0438+3004	J0510+1800	J0438+3004, J0510+1800, AB_Aur, J0435+2532	J0435+2532
uid___A002_Xfbb255_X2286	3	FAIL	Pass	The atmosphere was. very unstable	Percentage of calibration data flagged: 0.010 %; Achieved angular resolution is outside the expected range. Observed: 0.14, requested: 0.14 - 0.22	0.38	6	220.392	15-2617	44	0.00%	2.85	6-7	116.5	137	2022-07-20 14:03:55	2022-07-20 14:59:55	34.8	J0510+1800, AB_Aur	J0510+1800	J0510+1800	J0438+3004	J0510+1800	J0438+3004, J0510+1800, AB_Aur, J0435+2532	J0435+2532
uid___A002_Xfbb9c7_X6731	4	SUCCESS	Pass	Very high atmosphere unstability	Achieved angular resolution is outside the expected range. Observed: 0.13, requested: 0.14 - 0.22	0.65	6	220.392	15-2617	42	0.00%	2.37	5-6	116.5	123.62	2022-07-21 14:01:35	2022-07-21 15:20:52	47.42	J0510+1800, AB_Aur	J0510+1800	J0510+1800	J0438+3004	J0510+1800	J0438+3004, J0510+1800, AB_Aur, J0435+2532	J0435+2532
uid___A002_Xfbb9c7_Xd621	5	SUCCESS	Pass	The atmosphere was very unstable	Percentage of calibration data flagged: 0.010 %; Achieved angular resolution is outside the expected range. Observed: 0.14, requested: 0.14 - 0.22	1.5	6	220.392	15-2617	44	1.73%	0.84	2-3	116.5	81.444	2022-07-22 11:30:28	2022-07-22 12:49:58	47.33	J0510+1800, AB_Aur	J0510+1800	J0510+1800	J0438+3004	J0510+1800	J0438+3004, J0510+1800, AB_Aur, J0435+2532	J0435+2532
uid___A002_Xfbb9c7_Xe05e	6	SUCCESS	Pass	The atmosphere. was unstable	Achieved angular resolution is outside the expected range. Observed: 0.13, requested: 0.14 - 0.22	1.5	6	220.392	15-2617	41	0.00%	0.63	1-2	116.5	73.95	2022-07-22 12:59:16	2022-07-22 14:18:16	47.42	J0510+1800, AB_Aur	J0510+1800	J0510+1800	J0438+3004	J0510+1800	J0438+3004, J0510+1800, AB_Aur, J0435+2532	J0435+2532

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AB_Aur_a_06_TM1: member.uid___A001_X15a2_Xb6b.

Short baseline data (C-3 configuration)#

Below are further details on the TM2 scheduling block, compiled from a combination of the weblog and the QA reports. Note that you can scroll through this table horizontally.

Execution Block

Session

QA0 ExecBlock Status

QA0 Status

QA0 Comment

QA0 Warnings

Exec Fraction

Band

Repr. Frequency (GHz, Sky)

Baselines (m)

Antennas (total)

Shadowing

PWV (mm)

PWV Octile

Tsys (OT, K)

Tsys (EB, K)

Start

End

Time on AB Aur (min)

Calibrators: Atmosphere

Calibrators: Bandpass

Calibrators: Flux

Calibrators: Phase

Calibrators: Pointing

Calibrators: WVR

Observe Check Source

uid___A002_Xf7ad58_Xd406

1

SUCCESS

Pass

Some antennas shadowed due to high declination (11.6%)

Percentage of calibration data flagged: 0.500 %

1.5

6

220.392

14-500

41

11.63%

0.74

2-3

116.5

73

2022-04-19 7:25:22

2022-04-19 8:20:05

41

J0510+1800, AB_Aur

J0510+1800

J0438+3004

J0510+1800

J0438+3004, J0510+1800, AB_Aur

N/A

uid___A002_Xf8d822_Xa976 (discarded by ALMA pipeline)

2

FAIL

Semi-pass

APE2: 12m obs crash with ‘Failed to handle an interface method invocation’. no band set - problem in dataset

N/A

0

6

220.392

15-500

N/A

0.74

2-3

N/A

8.1

J0510+1800, AB_Aur

J0510+1800

J0438+3004

J0510+1800

J0438+3004, J0510+1800, AB_Aur

N/A

uid___A002_Xf8f6a9_X15c79

3

FAIL

Pass

DV 23 and DA54 presented issues. No other major issue.

Percentage of calibration data flagged: 0.020 %; Achieved angular resolution is outside the expected range. Observed: 0.55, requested: 0.64 - 0.96

1.5

6

220.392

15-680

45

12.79%

0.69

2-3

116.5

73.2

2022-05-15 18:05:13

2022-05-15 18:49:47

32.4

J0510+1800, AB_Aur

J0510+1800

J0438+3004

J0510+1800

J0438+3004, J0510+1800, AB_Aur

N/A

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AB_Aur_a_06_TM2: member.uid___A001_X15a2_Xb6d. The “second” execution block “uid___A002_Xf8d822_Xa976” was QA0 semi-pass, and was not included into the pipeline-delivered calibrated products. The QA0 comment (from the QA0 report) shows a fatal software error occurred and only 8 minutes of integration time on-source was achieved. We later looked at these data and considered re-running the pipeline calibration to include this EB, but in the end decided it was not worth it. The “third” execution block, “uid___A002_Xf8f6a9_X15c79”, is thus what we move forward with as “SB EB2”.

Correlator Setup#

Our correlator setup was designed for kinematic science. We placed five spectral windows (SPWs) over the four available basebands to target four molecular emission lines and the continuum.

ALMA Band 6 correlator setup. Note the third column gives SPW center frequency, not the transition rest frequency.

We centered one SPW at the \(^{13}\)CO \(J=2-1\) molecular emission line transition rest frequency (220.398 GHz), covering a bandwidth of 58.594 MHz with 1920 channels, resulting in the highest achievable spectral resolution of 41.510 m/s after default spectral averaging with \(N=2\) by Hanning smoothing within the correlator data processor. (This was our “representative” window in the OT.)

We placed a second SPW at the \(^{12}\)CO \(J=2-1\) rest frequency (230.538 GHz) covering the same bandwidth with the same number of channels, achieving a slighty higher spectral resolution of 39.684 m/s (due to the higher center frequency, of course).

A third SPW was centered at the C\(^{18}\)O \(J=2-1\) rest frequency (219.560 GHz), and a fourth at the SO \(6(5)-5(4)\) rest frequency (219.949 GHz). Each of these SPWS covered the same bandwidth (58.594 MHz) but with half as many channels (960 channels) because they share a baseband. Thus they achieve a lower spectral resolution of 83.336 m/s and 83.189 m/s respectively.

To enable self-calibration, our correlator setup sampled the continuum in a fifth SPW centered at 233.012 GHz with 128 channels each 15.625 MHz in width, obtaining the full available 2.0 GHz bandwidth.

The weblog provides a detailed summary of the correlator setup.

ALMA Band 6 correlator setup (“Science Windows” tab in the weblog).

Pipeline Products#

Each scheduling block (TM1 and TM2) was calibrated by the Cycle 8 ALMA pipeline. The final tasks in the pipeline additionally generate imaging products, which we can view to get an initial idea of what the observations show.

Channel maps (TM1)#

Pipeline-generated TM1 line images (task hif_makeimages).

Channel maps (TM2)#

Pipeline-generated TM2 line images (task hif_makeimages).

Spectral line profiles#

Our spectral windows cover a larger frequency range than the emission lines they target. It can be a good idea to take a look at what’s happening throughout the whole spectral window though, which we do the quick way here by creating spectral line profiles integrated over the full field of view. Note the different y-axis scale.