Asymmetric structure in Sgr A* at 3 mm from closure phase measurements with VLBA, GBT and LMT
Abstract
We present the results of a closure phase analysis of 3 mm very long baseline interferometry measurements performed on Sagittarius A* (Sgr A*). We have analysed observations made in 2015 May using the Very Long Baseline Array, the Robert C. Byrd Green Bank Telescope and the Large Millimeter Telescope Alfonso Serrano and obtained non-zero closure phase measurements on several station triangles - indicative of a non-point-symmetric source structure. The data are fitted with an asymmetric source structure model in Sgr A*, represented by a simple two-component model, which favours a fainter component due east of the main source. This result is discussed in light of a scattering screen with substructure or an intrinsically asymmetric source.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- October 2016
- DOI:
- 10.1093/mnras/stw1743
- arXiv:
- arXiv:1608.06515
- Bibcode:
- 2016MNRAS.462.1382B
- Keywords:
-
- accretion;
- accretion discs;
- techniques: interferometric;
- galaxies: active;
- galaxies: jets;
- radio continuum: galaxies;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- To be published in MNRAS. First published online July 19, 2016