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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.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0035-8711 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000804922200007 Approved  
  Call Number UAI @ alexi.delcanto @ Serial 1585  
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Author Casassus, S.; Christiaens, V.; Carcamo, M.; Perez, S.; Weber, P.; Ercolano, B.; van der Marel, N.; Pinte, C.; Dong, R.B.; Baruteau, C.; Cieza, L.; van Dishoeck, E.F.; Jordan, A.; Price, D.J.; Absil, O.; Arce-Tord, C.; Faramaz, V.; Flores, C.; Reggiani, M. doi  openurl
  Title A dusty filament and turbulent CO spirals in HD 135344B-SAO 206462 Type
  Year 2021 Publication Monthly Notices Of The Royal Astronomical Society Abbreviated Journal Mon. Not. Roy. Astron. Soc.  
  Volume 507 Issue 3 Pages 3789-3809  
  Keywords protoplanetary discs; accretion, accretion discs; planet-disc interactions  
  Abstract Planet-disc interactions build up local pressure maxima that may halt the radial drift of protoplanetary dust, and pile it up in rings and crescents. ALMA observations of the HD 135344B disc revealed two rings in the thermal continuum stemming from similar to mm-sized dust. At higher frequencies the inner ring is brighter relative to the outer ring, which is also shaped as a crescent rather than a full ring. In near-IR scattered light images, the disc is modulated by a two-armed grand-design spiral originating inside the ALMA inner ring. Such structures may be induced by a massive companion evacuating the central cavity, and by a giant planet in the gap separating both rings, that channels the accretion of small dust and gas through its filamentary wakes while stopping the larger dust from crossing the gap. Here we present ALMA observations in the J = (2 – 1) CO isotopologue lines and in the adjacent continuum, with up to 12 km baselines. Angular resolutions of similar to 0 ''.03 reveal the tentative detection of a filament connecting both rings, and which coincides with a local discontinuity in the pitch angle of the IR spiral, proposed previously as the location of the protoplanet driving this spiral. Line diagnostics suggests that turbulence, or superposed velocity components, is particularly strong in the spirals. The (CO)-C-12(2-1) 3D rotation curve points at stellocentric accretion at radii within the inner dust ring, with a radial velocity of up to similar to 5 per cent +/- 0.5 per cent Keplerian, which corresponds to an excessively large accretion rate of similar to 2 x 10(-6) M circle dot yr(-1) if all of the CO layer follows the (CO)-C-12(2-1) kinematics. This suggests that only the surface layers of the disc are undergoing accretion, and that the line broadening is due to superposed laminar flows.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0035-8711 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000708848000046 Approved  
  Call Number UAI @ alexi.delcanto @ Serial 1484  
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