Dust Echoes from Luminous Fast Blue Optical Transients
Luminous fast blue optical transients (LFBOTs) such as AT2018cow form a rare class of engine-powered explosions of uncertain origin. A hallmark feature of these events is radio/millimeter synchrotron emission powered by the interaction of fast ≳0.1 c ejecta and dense circumstellar material (CSM) ext...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/acae89 |
| _version_ | 1797701237285584896 |
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| author | Brian D. Metzger Daniel A. Perley |
| author_facet | Brian D. Metzger Daniel A. Perley |
| author_sort | Brian D. Metzger |
| collection | DOAJ |
| description | Luminous fast blue optical transients (LFBOTs) such as AT2018cow form a rare class of engine-powered explosions of uncertain origin. A hallmark feature of these events is radio/millimeter synchrotron emission powered by the interaction of fast ≳0.1 c ejecta and dense circumstellar material (CSM) extending to large radii ≳10 ^16 cm surrounding the progenitor. Assuming this CSM to be an outflow from the progenitor, we show that dust grains up to ∼1 μ m in size can form in the outflow in the years before the explosion. This dusty CSM would attenuate the transient’s ultraviolet emission prior to peak light, before being destroyed by the rising luminosity, reddening the premaximum colors (consistent with the premaximum red-to-blue color evolution of the LFBOT candidate MUSSES2020J). Reradiation by the dust before being destroyed generates a near-infrared (NIR) “echo” of luminosity ∼10 ^41 –10 ^42 erg s ^−1 lasting weeks, which is detectable over the transient’s rapidly fading blue continuum. We show that this dust echo is compatible with the previously unexplained NIR excess observed in AT2018cow. The gradual decay of the early NIR light curve can result from CSM, which is concentrated in a wide-angle equatorial outflow or torus, consistent with the highly aspherical geometry of AT2018cow’s ejecta. Premaximum optical/UV and NIR follow-up of LFBOTs provide a new probe of their CSM environments and place additional constraints on their progenitors. |
| first_indexed | 2024-03-12T04:33:34Z |
| format | Article |
| id | doaj.art-25f7c70fd89e408a82a0e7ed82053d51 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T04:33:34Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-25f7c70fd89e408a82a0e7ed82053d512023-09-03T09:58:16ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0194417410.3847/1538-4357/acae89Dust Echoes from Luminous Fast Blue Optical TransientsBrian D. Metzger0https://orcid.org/0000-0002-4670-7509Daniel A. Perley1https://orcid.org/0000-0001-8472-1996Department of Physics and Columbia Astrophysics Laboratory, Columbia University , New York, NY 10027, USA ; bmetzger@phys.columbia.edu; Center for Computational Astrophysics, Flatiron Institute , 162 5th Avenue, New York, NY 10010, USAAstrophysics Research Institute, Liverpool John Moores University , IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF, UKLuminous fast blue optical transients (LFBOTs) such as AT2018cow form a rare class of engine-powered explosions of uncertain origin. A hallmark feature of these events is radio/millimeter synchrotron emission powered by the interaction of fast ≳0.1 c ejecta and dense circumstellar material (CSM) extending to large radii ≳10 ^16 cm surrounding the progenitor. Assuming this CSM to be an outflow from the progenitor, we show that dust grains up to ∼1 μ m in size can form in the outflow in the years before the explosion. This dusty CSM would attenuate the transient’s ultraviolet emission prior to peak light, before being destroyed by the rising luminosity, reddening the premaximum colors (consistent with the premaximum red-to-blue color evolution of the LFBOT candidate MUSSES2020J). Reradiation by the dust before being destroyed generates a near-infrared (NIR) “echo” of luminosity ∼10 ^41 –10 ^42 erg s ^−1 lasting weeks, which is detectable over the transient’s rapidly fading blue continuum. We show that this dust echo is compatible with the previously unexplained NIR excess observed in AT2018cow. The gradual decay of the early NIR light curve can result from CSM, which is concentrated in a wide-angle equatorial outflow or torus, consistent with the highly aspherical geometry of AT2018cow’s ejecta. Premaximum optical/UV and NIR follow-up of LFBOTs provide a new probe of their CSM environments and place additional constraints on their progenitors.https://doi.org/10.3847/1538-4357/acae89SupernovaeCircumstellar dust |
| spellingShingle | Brian D. Metzger Daniel A. Perley Dust Echoes from Luminous Fast Blue Optical Transients The Astrophysical Journal Supernovae Circumstellar dust |
| title | Dust Echoes from Luminous Fast Blue Optical Transients |
| title_full | Dust Echoes from Luminous Fast Blue Optical Transients |
| title_fullStr | Dust Echoes from Luminous Fast Blue Optical Transients |
| title_full_unstemmed | Dust Echoes from Luminous Fast Blue Optical Transients |
| title_short | Dust Echoes from Luminous Fast Blue Optical Transients |
| title_sort | dust echoes from luminous fast blue optical transients |
| topic | Supernovae Circumstellar dust |
| url | https://doi.org/10.3847/1538-4357/acae89 |
| work_keys_str_mv | AT briandmetzger dustechoesfromluminousfastblueopticaltransients AT danielaperley dustechoesfromluminousfastblueopticaltransients |