{"about":{"site":"https://codewithpapers.app","non_affiliation":"Code with Papers and Syntology are not affiliated with, endorsed by, or sponsored by Papers with Code, Meta, or the pwc-archive mirror.","licence":"CC BY-SA 4.0","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","attribution":"https://codewithpapers.app/attribution","modified":"archive material modified by Syntology; see the attribution page"},"url":"/paper/at2018cow-a-luminous-millimeter-transient","title":"AT2018cow: a luminous millimeter transient","arxiv_id":"1810.10880","date":"2018-10-25","proceeding":null,"authors":["Anna Y. Q. Ho","E. Sterl Phinney","Vikram Ravi","S. R. Kulkarni","Glen Petitpas","Bjorn Emonts","Varun Bhalerao","Ray Blundell","S. Bradley Cenko","Dougal Dobie","Ryan Howie","Nikita Kamraj","Mansi M. Kasliwal","Tara Murphy","Daniel A. Perley","T. K. Sridharan","Ilsang Yoon"],"abstract":"We present detailed submillimeter- through centimeter-wave observations of the extraordinary extragalactic transient AT2018cow. The apparent characteristics -- the high radio luminosity, the long-lived emission plateau at millimeter bands, and the sub-relativistic velocity -- have no precedent. A basic interpretation of the data suggests $E_k \\gtrsim 10^{48}$ erg coupled to a fast but sub-relativistic ($v \\approx 0.13c$) shock in a dense ($n_e \\approx 3 \\times 10^{5}\\,$cm$^{-3}$) medium. We find that the X-ray emission is not naturally explained by an extension of the radio-submm synchrotron spectrum, nor by inverse Compton scattering of the dominant blackbody UVOIR photons by energetic electrons within the forward shock. By $\\Delta t \\approx20\\,$days, the X-ray emission shows spectral softening and erratic inter-day variability. Taken together, we are led to invoke an additional source of X-ray emission: the central engine of the event. Regardless of the nature of this central engine, this source heralds a new class of energetic transients shocking a dense medium, which at early times are most readily observed at millimeter wavelengths.","url_abs":"http://arxiv.org/abs/1810.10880v4","url_pdf":"http://arxiv.org/pdf/1810.10880v4.pdf","source":{"archive":"pwc-archive (Hugging Face), CC BY-SA 4.0","snapshot":"2025-07-28","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","row_kind":"links_only","authors_date_abstract":"arXiv metadata, CC0 1.0 (https://info.arxiv.org/help/license), from the Kaggle arXiv metadata snapshot of 2026-09-12"},"code_links":[{"paper_slug":"at2018cow-a-luminous-millimeter-transient","repo_url":"https://github.com/annayqho/AT2018cow","is_official":1,"mentioned_in_paper":1,"mentioned_in_github":1,"framework":"none","reach":null}],"tasks":[],"methods":[],"datasets_introduced":[],"methods_introduced":[],"results":[],"syntology":{"syntology_url":null,"atlas_url":null,"mcp":null,"developers":"https://syntology.ai/developers"},"arxiv_metadata":null,"syntology_extracted_results":null}