Related papers: SN 2014C: VLBI image shows a shell structure and d…
SN 2001em is a peculiar supernova, originally classified as Type Ib/c. About two years after the SN it was detected in the radio, showing a rising radio flux with an optically thin spectral slope, and it also displayed a large X-ray…
We compare a deep (37 ks) Chandra ACIS-S image of the M31 bulge to Local Group Survey narrow-band optical data and Very Large Array (VLA) radio data of the same region. Our precisely registered images reveal two new optical shells with…
As the shock and expanding shell of a supernova plow out through the circumstellar material at thousands of km/s, radio emission is generated. VLBI observations of this radio emission are presently the only means to directly image the…
We present multi-wavelength observations of SN2014C during the first 500 days. These observations represent the first solid detection of a young extragalactic stripped-envelope SN out to high-energy X-rays. SN2014C was the explosion of an…
We present two sequences of VLBI images of SN1993J in M81, with 24 images at 8.4 GHz and 19 images at 5.0 GHz, These sequences, from 50 d to ~9 yr after shock breakout, show the evolution of the expanding radio shell of an exploded star in…
We have imaged over 35 years of archival Very Large Array (VLA) observations of the nearby (d$_{\rm{L}}$ $=$ 3.15 Mpc) Type Ia supernovae SN\,1972E and SN\,1895B between 9 and 121 years post-explosion. No radio emission is detected,…
We report here on 5 GHz global very-long-baseline interferometry (VLBI) observations of SN 1986J, 16 yr after its explosion. We obtained a high-resolution image of the supernova, which shows a distorted shell of radio emission, indicative…
The Type Ib/c supernova SN 2001em was observed to have strong radio, X-ray, and Halpha emission at an age of about 2.5 yr. Although the radio and X-ray emission have been attributed to an off-axis gamma-ray burst, we model the emission as…
We present extensive radio and X-ray observations of the nearby Type Ic SN 2007gr in NGC 1058 obtained with the Very Large Array and the Chandra X-ray Observatory and spanning 5 to 150 days after explosion. Through our detailed modeling of…
We report on sensitive 1.4-GHz VLBI radio observations of the unusually luminous supernova remnant SNR 4449-1 in the galaxy NGC 4449, which gave us the first well-resolved image of this object. The remnant's radio morphology consists of two…
We present extensive multi-frequency VLA and VLBA observations of the radio-bright supernova (SN) IIb SN 2004C that span $\sim(40-2793)$ days post-explosion. We interpret the temporal evolution of the radio spectral energy distribution…
We present High Sensitivity Array (HSA) and enhanced Multi Element Remotely Linked Interferometer Network (eMERLIN) observations of the radio-loud broad-lined type Ic supernova PTF11qcj obtained $\sim7.5$ years after the explosion. Previous…
We present optical and NIR photometry and spectroscopy of SN 2013L for the first four years post-explosion. SN 2013L was a moderately luminous (M$_{r}$ = -19.0) Type IIn supernova (SN) that showed signs of strong shock interaction with the…
We present VLA images of the supernova remnant (SNR) 3C~391 at 74, 330, and 1465 MHz. This remnant has been known for some time to exhibit a turnover in its integrated radio continuum spectrum at frequencies < 100 MHz, indicative of…
We present a detailed analysis of the first very long baseline interferometry (VLBI) detection of the radio remnant of supernova 1987A. The VLBI data taken in 2007 and 2008 at 1.4 and 1.7 GHz, respectively, provide images sensitive to…
We investigate SN 2014C using three-dimensional hydrodynamic modeling, focusing on its early interaction with dense circumstellar medium (CSM). Our objective is to uncover the pre-supernova (SN) CSM structure and constrain the progenitor…
We report on multi-frequency Very Large Array (VLA) and Very Long Baseline Interferometry (VLBI) radio observations for a monitoring campaign of supernova SN$\,$2008iz in the nearby irregular galaxy M$\,$82. We fit two models to the data, a…
We report on phase-referenced 23 GHz Very-Long-Baseline-Interferometry (VLBI) observations of the type IIb supernova SN 2008ax, made with the Very Long Baseline Array (VLBA) on 2 April 2008 (33 days after explosion). These observations…
The high resolution obtained through the use of VLBI gives an unique opportunity to directly observe the interaction of an expanding radio supernova with its surrounding medium. We present here results from our VLBI observations of the…
SN 2014C was an unprecedented supernova (SN) that displayed a metamorphosis from Type Ib to Type IIn over $\sim$200 days. This transformation is consistent with a helium star having exploded in a cavity surrounded by a dense shell of the…