SN 2014C: VLBI image shows a shell structure and decelerated expansion. Issue 2 (4th January 2021)

• Record Type: Journal Article
• Authors: Bietenholz, Michael F; Bartel, Norbert; Kamble, Atish; Margutti, Raffaella; Matthews, David Jacob; Milisavljevic, Danny
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 502:Issue 2(2021)
• Page Start: 1694
• Page End: 1701
• Publication Date: 2021-01-04
• Subjects: Supernovae: individual: SN 2014C -- radio continuum: general; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/staa4003
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We report on new Very Long Baseline Interferometry radio measurements of supernova (SN) 2014C in the spiral galaxy NGC 7331, made with the European VLBI Network ∼5 yr after the explosion, as well as on flux density measurements made with the Jansky Very Large Array (VLA). SN 2014C was an unusual SN, initially of Type Ib, but over the course of ∼1 yr, it developed strong H α lines, implying the onset of strong interaction with some H-rich circumstellar medium (CSM). The expanding shock-front interacted with a dense shell of circumstellar material during the first year, but has now emerged from the dense shell and is expanding into the lower density CSM beyond. Our new VLBI observations show a relatively clear shell structure and continued expansion with some deceleration, with a suggestion that the deceleration is increasing at the latest times. Our multifrequency VLA observations show a relatively flat power-law spectrum with S ν ∝ ν −0.56 ± 0.03, and show no decline in the radio luminosity since t ∼ 1 yr.