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Author Casassus, S.; Carcamo, M. doi  openurl
  Title Variable structure in the PDS 70 disc and uncertainties in radio-interferometric image restoration Type
  Year 2022 Publication Monthly Notices Of The Royal Astronomical Society Abbreviated Journal Mon. Not. Roy. Astron. Soc.  
  Volume 513 Issue 4 Pages 5790-5798  
  Keywords techniques: interferometric; planets and satellites: formation; protoplanetary discs; stars: individual: PDS 70  
  Abstract The compact mm-wavelength signal in the central cavity of the PDS 70 disc, revealed by deep ALMA observations, is aligned with unresolved H alpha emission, and is thought to stem from a circumplanetary disc (CPD) around PDS 70c. We revisit the available ALMA data on PDS 70c with alternative imaging strategies, and with special attention to uncertainties and to the impact of the so-called 'JvM correction', which is thought to improve the dynamic range of restored images. We also propose a procedure for the alignment and joint imaging of multi-epoch visibility data. We find that the JvM correction exaggerates the peak signal-to-noise of the data, by up to a factor of 10. In the case of PDS 70, we recover the detection of PDS 70c from the 2019 July data, but only at 8 sigma. However, its non-detection in 2017 Dec. suggests that PDS 70c is variable by at least 42 per cent +/- 13 per cent over a 1.75 yr time-span, so similar to models of the H alpha variability. We also pick up fine structure in the inner disc, such that its peak is offset by similar to 0 ''.04 from the disc centre. The inner disc is variable too, which we tentatively ascribe to Keplerian rotation as well as intrinsic morphological changes.  
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  ISSN 0035-8711 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000804922200007 Approved  
  Call Number UAI @ alexi.delcanto @ Serial 1585  
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