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| Format: | Preprint |
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2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2509.00951 |
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| _version_ | 1866918133530361856 |
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| author | LeBaron, Natalie Margutti, Raffaella Chornock, Ryan Nayana, A. J. Aspegren, Olivia Lu, Wenbin Metzger, Brian Kasen, Daniel Brink, Thomas Campana, Sergio D'Avanzo, Paolo Faber, Jakob Ferro, Matteo Filippenko, Alex Foley, Ryan Guo, Xinze Hammerstein, Erica Jha, Saurabh Kilpatrick, Charles Migliori, Giulia Milisavljevic, Dan Patra, Kishore Sears, Huei Swift, Jonathan Tinyanont, Samaporn Ravi, Vikram Yao, Yuhan Alexander, Kate Arunachalam, Prasiddha Berger, Edo Bright, Joe Cynamon, Chuck Davis, Kyle Garretson, Braden Guhathakurta, Puragra Jacobson-Galan, Wynn Jones, David Kaur, Ravjit Kimura, Stefan Laskar, Tanmoy Nuñez, Morgan Schwab, Michaela Soraisam, Monika Suzuki, Nao Taggart, Kirsty Wiston, Eli Yang, Yi Zheng, WeiKang |
| author_facet | LeBaron, Natalie Margutti, Raffaella Chornock, Ryan Nayana, A. J. Aspegren, Olivia Lu, Wenbin Metzger, Brian Kasen, Daniel Brink, Thomas Campana, Sergio D'Avanzo, Paolo Faber, Jakob Ferro, Matteo Filippenko, Alex Foley, Ryan Guo, Xinze Hammerstein, Erica Jha, Saurabh Kilpatrick, Charles Migliori, Giulia Milisavljevic, Dan Patra, Kishore Sears, Huei Swift, Jonathan Tinyanont, Samaporn Ravi, Vikram Yao, Yuhan Alexander, Kate Arunachalam, Prasiddha Berger, Edo Bright, Joe Cynamon, Chuck Davis, Kyle Garretson, Braden Guhathakurta, Puragra Jacobson-Galan, Wynn Jones, David Kaur, Ravjit Kimura, Stefan Laskar, Tanmoy Nuñez, Morgan Schwab, Michaela Soraisam, Monika Suzuki, Nao Taggart, Kirsty Wiston, Eli Yang, Yi Zheng, WeiKang |
| contents | We present an extensive photometric and spectroscopic ultraviolet-optical-infrared campaign on the luminous fast blue optical transient (LFBOT) AT 2024wpp over the first ~100 d. AT 2024wpp is the most luminous LFBOT discovered to date, with $L_{\rm{pk}}\approx(2-4)\times10^{45}$ erg s$^{-1}$ (5-10 times that of the prototypical AT 2018cow). This extreme luminosity enabled the acquisition of the most detailed LFBOT UV light curve thus far. In the first ~45 d, AT 2024wpp radiated $>10^{51}$ erg, surpassing AT 2018cow by an order of magnitude and requiring a power source beyond the radioactive $^{56}$Ni decay of traditional supernovae. Like AT 2018cow, the UV-optical spectrum of AT 2024wpp is dominated by a persistently blue thermal continuum throughout our monitoring, with blackbody parameters at peak of T>30,000 K and $R_{\rm{BB}}/t\approx0.2-0.3c$. A temperature of $\gtrsim$20,000 K is maintained thereafter without evidence for cooling. We interpret the featureless spectra as a consequence of continuous energy injection from a central source of high-energy emission which maintains high ejecta ionization. After 35 d, faint (equivalent width <10 Å) H and He spectral features with kinematically separate velocity components centered at 0 km s$^{-1}$ and -6400 km s$^{-1}$ emerge, implying spherical symmetry deviations. A near-infrared excess of emission above the optical blackbody emerges between 20-30 d with a power-law spectrum $F_{\rmν,NIR}\proptoν^{-0.3}$ at 30 d. We interpret this distinct emission component as either reprocessing of early UV emission in a dust echo or free-free emission in an extended medium above the optical photosphere. LFBOT asphericity and multiple outflow components (including mildly relativistic ejecta) together with the large radiated energy are naturally realized by super-Eddington accretion disks around neutron stars or black holes and their outflows. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2509_00951 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | The Most Luminous Known Fast Blue Optical Transient AT 2024wpp: Unprecedented Evolution and Properties in the Ultraviolet to the Near-Infrared LeBaron, Natalie Margutti, Raffaella Chornock, Ryan Nayana, A. J. Aspegren, Olivia Lu, Wenbin Metzger, Brian Kasen, Daniel Brink, Thomas Campana, Sergio D'Avanzo, Paolo Faber, Jakob Ferro, Matteo Filippenko, Alex Foley, Ryan Guo, Xinze Hammerstein, Erica Jha, Saurabh Kilpatrick, Charles Migliori, Giulia Milisavljevic, Dan Patra, Kishore Sears, Huei Swift, Jonathan Tinyanont, Samaporn Ravi, Vikram Yao, Yuhan Alexander, Kate Arunachalam, Prasiddha Berger, Edo Bright, Joe Cynamon, Chuck Davis, Kyle Garretson, Braden Guhathakurta, Puragra Jacobson-Galan, Wynn Jones, David Kaur, Ravjit Kimura, Stefan Laskar, Tanmoy Nuñez, Morgan Schwab, Michaela Soraisam, Monika Suzuki, Nao Taggart, Kirsty Wiston, Eli Yang, Yi Zheng, WeiKang High Energy Astrophysical Phenomena We present an extensive photometric and spectroscopic ultraviolet-optical-infrared campaign on the luminous fast blue optical transient (LFBOT) AT 2024wpp over the first ~100 d. AT 2024wpp is the most luminous LFBOT discovered to date, with $L_{\rm{pk}}\approx(2-4)\times10^{45}$ erg s$^{-1}$ (5-10 times that of the prototypical AT 2018cow). This extreme luminosity enabled the acquisition of the most detailed LFBOT UV light curve thus far. In the first ~45 d, AT 2024wpp radiated $>10^{51}$ erg, surpassing AT 2018cow by an order of magnitude and requiring a power source beyond the radioactive $^{56}$Ni decay of traditional supernovae. Like AT 2018cow, the UV-optical spectrum of AT 2024wpp is dominated by a persistently blue thermal continuum throughout our monitoring, with blackbody parameters at peak of T>30,000 K and $R_{\rm{BB}}/t\approx0.2-0.3c$. A temperature of $\gtrsim$20,000 K is maintained thereafter without evidence for cooling. We interpret the featureless spectra as a consequence of continuous energy injection from a central source of high-energy emission which maintains high ejecta ionization. After 35 d, faint (equivalent width <10 Å) H and He spectral features with kinematically separate velocity components centered at 0 km s$^{-1}$ and -6400 km s$^{-1}$ emerge, implying spherical symmetry deviations. A near-infrared excess of emission above the optical blackbody emerges between 20-30 d with a power-law spectrum $F_{\rmν,NIR}\proptoν^{-0.3}$ at 30 d. We interpret this distinct emission component as either reprocessing of early UV emission in a dust echo or free-free emission in an extended medium above the optical photosphere. LFBOT asphericity and multiple outflow components (including mildly relativistic ejecta) together with the large radiated energy are naturally realized by super-Eddington accretion disks around neutron stars or black holes and their outflows. |
| title | The Most Luminous Known Fast Blue Optical Transient AT 2024wpp: Unprecedented Evolution and Properties in the Ultraviolet to the Near-Infrared |
| topic | High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2509.00951 |