ALMA-IMF data update

Adam Ginsburg

For the data reduction team:
Timea Csengeri, Roberto Galván-Madrid, Hongli Liu, Yohan Pouteau, Andrés Guzman, Fernando Olguin, Fabien Louvet, Ana Lopez-Sepulcre, Nichol Cunningham, Manuel Fernández López, Tapas Baug, Melisse Bonfand
Slides available at https://keflavich.github.io/talks/almaimf_meeting_May2020.html. Use arrow keys to navigate.

Very quick summary

  • Clean-continuum, self-calibrated, 12m-only data are ready for use
  • Best-sensitivity "bsens" continuum (contains line contamination) images are mostly ready
  • Some 7m+12m combined data are available, but most fields are not
  • Line data first-pass cubes are undergoing QA

Data Reduction Team:

Continuum Deliveries:
  • Hongli Liu (G353)
  • Fabien Louvet (G12.80)
  • Timea Csengeri (G351.77, G328.25, G337.92)
  • Andrés Guzman (G10.62)
  • Roberto Galván-Madrid (G333.60)
  • Fernando Olguin (G327, G338 B3)
  • Patricio Sanhueza (G338 B6)
  • Ana Lopez-Sepulcre (G008.67)
  • Nichol Cunningham (G008.67)
  • Yohan Pouteau (W43-MM1, W43-MM2, W43-MM3)
  • Thomas Nony (W43-MM2, W43-MM3)
  • Adam Ginsburg (W51-E, W51-IRS2)
Line Inspection:
  • Manuel Fernández López (N2H+)
  • Hongli Liu (12CO, C18O)
  • Roberto Galván-Madrid (H41α)
  • Tapas Baug (H2CO)

Data Team activity

We have substantially improved the data over what was delivered:
  • Assessed calibration (inspected weblogs, etc)
  • Corrected broken calibrations
  • Combined 12m configurations
  • Imaged with & without line flagging
  • Combined 12m with 7m data
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Self-Calibration

Before self-calibration, data suffer from severe dynamic range limitations. W43-MM2 B6

Self-Calibration: process

  • Mosaic image created
  • Image is cleaned within a custom mask
  • Each pointing in the mosaic has gain solutions determined
  • Those pointings with S/N > 5 for all antennae are kept and used to calibrate remainder
  • Repeat, each time cleaning more deeply

Self-Calibration: process

G010.62 B3

Self-Calibration: effect

Self-Calibration: Summary


It works, and works well, but requires care in cleaning.

Substantial dynamic range improvements achieved for most fields.

Self-calibration will be applied to line data.

Data Quality figures

We rarely reached the requested noise level.

Data Quality figures

We generally reached the target beam size to within ALMA-defined metrics

Data Quality figures

Most of our images have high dynamic range

BSENS and Lines

We excluded lines to create "cleanest" continuum maps based on the default findContinuum script in the pipeline.

Continuum Vs Lines

Continuum selection doesn't always work. W51-E, for example, is a forest - the peak spectrum shows emission lines everywhere
W51-E B6

Continuum Vs Lines

Most regions are better behaved overall G351.77 B6

BSENS has improved sensitivity

With full bandwidth, we're closer to the target sensitivity in most cases, but still high.

BSENS has improved sensitivity

G351.77 B3 is one of the best examples, with substantially improved noise. G351.77 B3

BSENS has improved sensitivity

Some of the excesses are substantial, and pretty interesting looking G010.62 B6

BSENS has improved sensitivity

Band 6 has the most "contamination" W51-IRS2 B6

7m + 12m combination

  • Not as advanced as 12m-only
  • Self-calibration does not succeed in many cases
  • 7m+12m images are generally more noisy
  • There are some successes, but generally 7m+12m data should not be used in the current iteration

7m + 12m combination

7m + 12m combination

Good example: G333.60 B6

Description of the Data

  • Filenames:
    {field}_{uid}_continuum_merged_{bsens?}_{configuration}_{robust}_{selfcal}{suffix}
    E.g.:
    W51-E_B3_uid___A001_X1296_X10b_continuum_merged_12M_robust0_selfcal6_finaliter.image.tt0.fits
  • Fields: G008.67 G337.92 W43-MM3 G328.25 G351.77 G012.80 G327.29 W43-MM1 G010.62 W51-IRS2 W43-MM2 G333.60 G338.93 W51-E G353.41
  • Configuration: 12m, 7m, 7m12m
  • Robust: -2, 0, 2

Description of the Data

Headers contain HISTORY entries describing the specific version of the pipeline (a git hash) and the imaging parameters used.
DATE = '2020-05-10T01:28:35.526000'
ORIGIN = 'CASA 5.6.0-60'
GIT_VERS= 'a58df55 '
GIT_DATE= '2020-05-06'

Description of the Data

For internal release, the data are: