The BTSbot-nearby discovery of SN 2024jlf: rapid, autonomous follow-up probes interaction in an 18.5 Mpc Type IIP supernova

Nabeel Rehemtulla; W. V. Jacobson-Galán; Avinash Singh; Adam A. Miller; Charles D. Kilpatrick; K-Ryan Hinds; Chang Liu; Steve Schulze; Jesper Sollerman; Theophile Jegou du Laz; Tomás Ahumada; Katie Auchettl; S. J. Brennan; Michael W. Coughlin; Christoffer Fremling; Anjasha Gangopadhyay; Daniel A. Perley; Nikolaus Z. Prusinski; Josiah Purdum; Yu-Jing Qin; Sara Romagnoli; Jennifer Shi; Jacob L. Wise; Tracy X. Chen; Steven L. Groom; David O. Jones; Mansi M. Kasliwal; Roger Smith; Niharika Sravan; Shrinivas R. Kulkarni

arXiv · 2501.18686

The BTSbot-nearby discovery of SN 2024jlf: rapid, autonomous follow-up probes interaction in an 18.5 Mpc Type IIP supernova

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Abstract

We present observations of the Type IIP supernova (SN) 2024jlf, including spectroscopy beginning just 0.7 days ($\sim$17 hours) after first light. Rapid follow-up was enabled by the new $\texttt{BTSbot-nearby}$ program, which involves autonomously triggering target-of-opportunity requests for new transients in Zwicky Transient Facility data that are coincident with nearby ($D<60$ Mpc) galaxies and identified by the $\texttt{BTSbot}$ machine learning model. Early photometry and non-detections shortly prior to first light show that SN 2024jlf initially brightened by $>$4 mag/day, quicker than $\sim$90% of Type II SNe. Early spectra reveal weak flash ionization features: narrow, short-lived ($1.3 < τ~\mathrm{[d]} < 1.8$) emission lines of H$α$, He II, and C IV. Assuming a wind velocity of $v_w=50$ km s$^{-1}$, these properties indicate that the red supergiant progenitor exhibited enhanced mass-loss in the last year before explosion. We constrain the mass-loss rate to $10^{-4} < \dot{M}~\mathrm{[M_\odot~yr^{-1}]} < 10^{-3}$ by matching observations to model grids from two independent radiative hydrodynamics codes. $\texttt{BTSbot-nearby}$ automation minimizes spectroscopic follow-up latency, enabling the observation of ephemeral early-time phenomena exhibited by transients.

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Nabeel Rehemtulla, W. V. Jacobson-Galán, Avinash Singh, Adam A. Miller, Charles D. Kilpatrick, K-Ryan Hinds, Chang Liu, Steve Schulze, Jesper Sollerman, Theophile Jegou du Laz, Tomás Ahumada, Katie Auchettl, S. J. Brennan, Michael W. Coughlin, Christoffer Fremling, Anjasha Gangopadhyay, Daniel A. Perley, Nikolaus Z. Prusinski, Josiah Purdum, Yu-Jing Qin, Sara Romagnoli, Jennifer Shi, Jacob L. Wise, Tracy X. Chen, Steven L. Groom, David O. Jones, Mansi M. Kasliwal, Roger Smith, Niharika Sravan, Shrinivas R. Kulkarni. 2025-04-21. The BTSbot-nearby discovery of SN 2024jlf: rapid, autonomous follow-up probes interaction in an 18.5 Mpc Type IIP supernova. https://arxiv.org/abs/2501.18686

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