RY007
e-EVN: rm015, ry007a, ey031, rsg11
VLBI observation of nearby GRBs offer the unique possibility of resolving the afterglow, constraining the size, and measuring the expansion rate of the emitting region, which probe the distribution and density of the circumstellar medium. AT2018cow, discovered 10 days ago, is identified as a type Ic SN from its broad-line optical spectrum, and also as a GRB from its high luminosity and featureless spectrum in X-ray. AT2018cow is associated with a galaxy CGCG 137-068 at z = 0.014, making it the closest GRB found to date. Currently the radio flux density peaks at millimeter wavelengths. Two months later, the peak is expected to shift to centimeter wavelength. We propose high-sensitivity VLBI observations at C band with full EVN array to image the structure, and to accurately constrain the size of the afterglow. The morphology, symmetric or asymmetric, sheds light on the geometry of the GRB afterglow. The determined size yields an upper limit to the expansion rate of the afterglow.
Observation pages at the EVN archive:
This data is part of the archive of VLBI data maintained by JIVE on behalf of the EVN, a network of radio telescopes located primarily in Europe and Asia, with additional antennas in South Africa. The EVN archive itself has the DOI https://doi.org/10.17616/R3Z197