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| Auteurs principaux: | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Preprint |
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2025
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| Accès en ligne: | https://arxiv.org/abs/2509.00952 |
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| author | Nayana, A. J. Margutti, Raffaella Wiston, Eli Laskar, Tanmoy Migliori, Giulia Chornock, Ryan Galvin, Timothy J. LeBaron, Natalie Hajela, Aprajita Christy, Collin T. Sfaradi, Itai Tsuna, Daichi Aspegren, Olivia De Colle, Fabio Metzger, Brian D. Lu, Wenbin Beniamini, Paz Kasen, Daniel Berger, Edo Grefenstette, Brian W. Alexander, Kate D. Anupama, G. C. Coppejans, Deanne L. Cruz, Luigi F. DeBoer, David R Drout, Maria R. Farah, Wael Huang, Xiaoshan Jacobson-Galán, W. V. Milisavljevic, Dan Pollak, Alexander W. Roth, Nathan J. Sears, Huei Siemion, Andrew Sheikh, Sofia Z. Steiner, James F. Vurm, Indrek |
| author_facet | Nayana, A. J. Margutti, Raffaella Wiston, Eli Laskar, Tanmoy Migliori, Giulia Chornock, Ryan Galvin, Timothy J. LeBaron, Natalie Hajela, Aprajita Christy, Collin T. Sfaradi, Itai Tsuna, Daichi Aspegren, Olivia De Colle, Fabio Metzger, Brian D. Lu, Wenbin Beniamini, Paz Kasen, Daniel Berger, Edo Grefenstette, Brian W. Alexander, Kate D. Anupama, G. C. Coppejans, Deanne L. Cruz, Luigi F. DeBoer, David R Drout, Maria R. Farah, Wael Huang, Xiaoshan Jacobson-Galán, W. V. Milisavljevic, Dan Pollak, Alexander W. Roth, Nathan J. Sears, Huei Siemion, Andrew Sheikh, Sofia Z. Steiner, James F. Vurm, Indrek |
| contents | We present X-ray (0.3--79 keV) and radio (0.25--203 GHz) observations of the most luminous Fast Blue Optical Transient (LFBOT) AT\,2024wpp at $z=0.0868$, spanning 2--280 days after first light. AT 2024wpp shows luminous ($L_{\rm X} \approx 1.5 \times 10^{43}\, \rm erg\,s^{-1}$), variable X-ray emission with a Compton hump peaking at $δt \approx 50$ days. The X-ray spectrum evolves from a soft ($F_ν \propto ν^{-0.6}$) to an extremely hard state ($F_ν \propto ν^{1.26}$) accompanied by a re-brightening at $δt \approx 50$\,days. The X-ray emission properties favor an embedded high-energy source shining through asymmetric expanding ejecta. We detect radio emission peaking at $L_{\rm 9\,GHz} \approx 1.7 \times 10^{29}\,\rm erg\,s^{-1}\,Hz^{-1}$ at $δt \approx 73$ days. The spectral evolution is unprecedented: the early millimeter fluxes rise nearly an order of magnitude during $δt \approx 17-32$ days followed by a decline in spectral peak fluxes. We model the radio emission as synchrotron radiation from an expanding blast wave interacting with a dense environment ($\dot{M} \sim 10^{-3}\, \rm M_{\odot}\,yr^{-1}$ for $v_{\rm w} = 1000\,\rm km\,s^{-1}$). The inferred outflow velocities increase from $Γβc \approx 0.07\, \rm to\,0.42c$ during $δt \approx 32-73$ days, indicating an accelerating blast-wave. We interpret these observations as a shock propagating through a dense shell of radius $\approx 10^{16}$\,cm, then accelerating into a steep density profile $ρ_{\rm CSM}(r) \propto r^{-3.1}$. All radio-bright LFBOTs exhibit similar circumstellar medium (CSM) density profiles ($ρ_{\rm CSM} \propto r^{-3}$), suggesting similar progenitor processes. The X-ray and radio properties favor a progenitor involving super-Eddington accretion onto a compact object launching mildly-relativistic disk-wind outflows. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2509_00952 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | The Most Luminous Known Fast Blue Optical Transient AT 2024wpp: Unprecedented Evolution and Properties in the X-rays and Radio Nayana, A. J. Margutti, Raffaella Wiston, Eli Laskar, Tanmoy Migliori, Giulia Chornock, Ryan Galvin, Timothy J. LeBaron, Natalie Hajela, Aprajita Christy, Collin T. Sfaradi, Itai Tsuna, Daichi Aspegren, Olivia De Colle, Fabio Metzger, Brian D. Lu, Wenbin Beniamini, Paz Kasen, Daniel Berger, Edo Grefenstette, Brian W. Alexander, Kate D. Anupama, G. C. Coppejans, Deanne L. Cruz, Luigi F. DeBoer, David R Drout, Maria R. Farah, Wael Huang, Xiaoshan Jacobson-Galán, W. V. Milisavljevic, Dan Pollak, Alexander W. Roth, Nathan J. Sears, Huei Siemion, Andrew Sheikh, Sofia Z. Steiner, James F. Vurm, Indrek High Energy Astrophysical Phenomena We present X-ray (0.3--79 keV) and radio (0.25--203 GHz) observations of the most luminous Fast Blue Optical Transient (LFBOT) AT\,2024wpp at $z=0.0868$, spanning 2--280 days after first light. AT 2024wpp shows luminous ($L_{\rm X} \approx 1.5 \times 10^{43}\, \rm erg\,s^{-1}$), variable X-ray emission with a Compton hump peaking at $δt \approx 50$ days. The X-ray spectrum evolves from a soft ($F_ν \propto ν^{-0.6}$) to an extremely hard state ($F_ν \propto ν^{1.26}$) accompanied by a re-brightening at $δt \approx 50$\,days. The X-ray emission properties favor an embedded high-energy source shining through asymmetric expanding ejecta. We detect radio emission peaking at $L_{\rm 9\,GHz} \approx 1.7 \times 10^{29}\,\rm erg\,s^{-1}\,Hz^{-1}$ at $δt \approx 73$ days. The spectral evolution is unprecedented: the early millimeter fluxes rise nearly an order of magnitude during $δt \approx 17-32$ days followed by a decline in spectral peak fluxes. We model the radio emission as synchrotron radiation from an expanding blast wave interacting with a dense environment ($\dot{M} \sim 10^{-3}\, \rm M_{\odot}\,yr^{-1}$ for $v_{\rm w} = 1000\,\rm km\,s^{-1}$). The inferred outflow velocities increase from $Γβc \approx 0.07\, \rm to\,0.42c$ during $δt \approx 32-73$ days, indicating an accelerating blast-wave. We interpret these observations as a shock propagating through a dense shell of radius $\approx 10^{16}$\,cm, then accelerating into a steep density profile $ρ_{\rm CSM}(r) \propto r^{-3.1}$. All radio-bright LFBOTs exhibit similar circumstellar medium (CSM) density profiles ($ρ_{\rm CSM} \propto r^{-3}$), suggesting similar progenitor processes. The X-ray and radio properties favor a progenitor involving super-Eddington accretion onto a compact object launching mildly-relativistic disk-wind outflows. |
| title | The Most Luminous Known Fast Blue Optical Transient AT 2024wpp: Unprecedented Evolution and Properties in the X-rays and Radio |
| topic | High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2509.00952 |