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| Main Authors: | , , , , , , , , , , |
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| Format: | Preprint |
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2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2506.19071 |
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| _version_ | 1866909883824078848 |
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| author | Griffith, Olivia Showerman, Grace Sarbadhicary, Sumit K. Harris, Chelsea E. Chomiuk, Laura Sollerman, Jesper Lundqvist, Peter Moldon, Javier Perez-Torres, Miguel Kool, Erik C. Moriya, Takashi J. |
| author_facet | Griffith, Olivia Showerman, Grace Sarbadhicary, Sumit K. Harris, Chelsea E. Chomiuk, Laura Sollerman, Jesper Lundqvist, Peter Moldon, Javier Perez-Torres, Miguel Kool, Erik C. Moriya, Takashi J. |
| contents | Type Ia-CSM supernovae (SNe) are a rare and peculiar subclass of thermonuclear SNe characterized by emission lines of hydrogen or helium, indicative of a high-density circumstellar medium (CSM). Their implied mass-loss rates of $\sim 10^{-4}-10^{-1}$ M$_{\odot}$ yr$^{-1}$ (assuming $\mathrm{ \sim 100 \ km\ s^{-1}}$ winds) from optical observations are generally in excess of values observed in realistic SN Ia progenitors. In this paper, we present an independent study of CSM densities around a sample of 29 archival Ia-CSM SNe using radio observations with the Very Large Array at 6 GHz. Motivated by the late ($\sim$2 yr) radio detection of the Ia-CSM SN 2020eyj, we observed old ($>$1 yr) SNe where we are more likely to see the emergent synchrotron emission that may have been suppressed earlier by free-free absorption by the CSM. We do not detect radio emission down to 3$σ$ limits of $\sim$35 $μ$Jy in our sample. The only radio-detected candidate in our sample, SN 2022esa, was likely mis-classified as a Ia-CSM with early spectra, and appears more consistent with a peculiar Ic based on later-epochs. Assuming a wind-like CSM with temperatures between $2 \times 10^4$ K and $10^5$ K, and magnetic field-to-shock energy fraction ($ε_B$) = $0.01-0.1$, the radio upper limits rule out mass-loss rates between $\sim 10^{-4}-10^{-2}$ M$_{\odot}$ yr$^{-1}$ (100 km s$^{-1}$)$^{-1}$. This is somewhat in tension with the estimates from optical observations, and may indicate that more complex CSM geometries and/or lower values of $ε_B$ may be present. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2506_19071 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | A Late-time Radio Survey of Type Ia-CSM Supernovae with the Very Large Array Griffith, Olivia Showerman, Grace Sarbadhicary, Sumit K. Harris, Chelsea E. Chomiuk, Laura Sollerman, Jesper Lundqvist, Peter Moldon, Javier Perez-Torres, Miguel Kool, Erik C. Moriya, Takashi J. High Energy Astrophysical Phenomena Type Ia-CSM supernovae (SNe) are a rare and peculiar subclass of thermonuclear SNe characterized by emission lines of hydrogen or helium, indicative of a high-density circumstellar medium (CSM). Their implied mass-loss rates of $\sim 10^{-4}-10^{-1}$ M$_{\odot}$ yr$^{-1}$ (assuming $\mathrm{ \sim 100 \ km\ s^{-1}}$ winds) from optical observations are generally in excess of values observed in realistic SN Ia progenitors. In this paper, we present an independent study of CSM densities around a sample of 29 archival Ia-CSM SNe using radio observations with the Very Large Array at 6 GHz. Motivated by the late ($\sim$2 yr) radio detection of the Ia-CSM SN 2020eyj, we observed old ($>$1 yr) SNe where we are more likely to see the emergent synchrotron emission that may have been suppressed earlier by free-free absorption by the CSM. We do not detect radio emission down to 3$σ$ limits of $\sim$35 $μ$Jy in our sample. The only radio-detected candidate in our sample, SN 2022esa, was likely mis-classified as a Ia-CSM with early spectra, and appears more consistent with a peculiar Ic based on later-epochs. Assuming a wind-like CSM with temperatures between $2 \times 10^4$ K and $10^5$ K, and magnetic field-to-shock energy fraction ($ε_B$) = $0.01-0.1$, the radio upper limits rule out mass-loss rates between $\sim 10^{-4}-10^{-2}$ M$_{\odot}$ yr$^{-1}$ (100 km s$^{-1}$)$^{-1}$. This is somewhat in tension with the estimates from optical observations, and may indicate that more complex CSM geometries and/or lower values of $ε_B$ may be present. |
| title | A Late-time Radio Survey of Type Ia-CSM Supernovae with the Very Large Array |
| topic | High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2506.19071 |