The <tt>BTSbot-nearby</tt> Discovery of SN 2024jlf: Rapid, Autonomous Follow-up Probes Interaction in an 18.5 Mpc Type IIP Supernova
Abstract We present observations of the Type IIP supernova (SN) SN 2024jlf, including spectroscopy beginning just 0.7 days (∼17 hr) after first light. Rapid follow-up was enabled by the new 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 BTSbot machine learning model. Early photometry and nondetections shortly prior to first light show that SN 2024jlf initially brightened by >4 mag day −1 , quicker than ∼90% of Type II SNe. Early spectra reveal weak flash ionization features: narrow, short-lived (1.3 < τ [days] < 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 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>1</mml:mn> <mml:msup> <mml:mn>0</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>4</mml:mn> </mml:mrow> </mml:msup> <mml:mo><</mml:mo> <mml:mover accent="true"> <mml:mi>M</mml:mi> <mml:mo>̇</mml:mo> </mml:mover> <mml:mspace width="0.25em"/> <mml:mo stretchy="false">[</mml:mo> <mml:msub> <mml:mi>M</mml:mi> <mml:mo>⊙</mml:mo> </mml:msub> <mml:mspace width="0.25em"/> <mml:msup> <mml:mi>yr</mml:mi> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> <mml:mo stretchy="false">]</mml:mo> <mml:mo><</mml:mo> <mml:mn>1</mml:mn> <mml:msup> <mml:mn>0</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>3</mml:mn> </mml:mrow> </mml:msup> </mml:math> by matching observations to model grids from two independent radiative hydrodynamics codes. BTSbot-nearby automation minimizes spectroscopic follow-up latency, enabling the observation of ephemeral early-time phenomena exhibited by transients.
Authors
- Yu-Jing Qin (ORCID: https://orcid.org/0000-0003-3658-6026)
- C. D. Kilpatrick (ORCID: https://orcid.org/0000-0002-5740-7747)
- S. Brennan (ORCID: https://orcid.org/0000-0003-1325-6235)
- D. O. Jones (ORCID: https://orcid.org/0000-0002-6230-0151)
- X. Chen (ORCID: https://orcid.org/0000-0001-9152-6224)
- Jacob Wise (ORCID: https://orcid.org/0000-0003-0733-2916)
- Nabeel Rehemtulla (ORCID: https://orcid.org/0000-0002-5683-2389)
- Niharika Sravan
- Adam A. Miller (ORCID: https://orcid.org/0000-0001-9515-478X)
- J. Sollerman (ORCID: https://orcid.org/0000-0003-1546-6615)
- Josiah Purdum (ORCID: https://orcid.org/0000-0003-1227-3738)
- K-Ryan Hinds (ORCID: https://orcid.org/0000-0002-0129-806X)
- C. Fremling (ORCID: https://orcid.org/0000-0002-4223-103X)
- S. R. Kulkarni (ORCID: https://orcid.org/0000-0001-5390-8563)
- D. A. Perley (ORCID: https://orcid.org/0000-0001-8472-1996)
- M. W. Coughlin (ORCID: https://orcid.org/0000-0002-8262-2924)
- Steve Schulze (ORCID: https://orcid.org/0000-0001-6797-1889)
- Katie Auchettl (ORCID: https://orcid.org/0000-0002-4449-9152)
- W. V. Jacobson-Galán (ORCID: https://orcid.org/0000-0002-3934-2644)
- Avinash Singh (ORCID: https://orcid.org/0000-0003-2091-622X)
- Steven L. Groom (ORCID: https://orcid.org/0000-0001-5668-3507)
- Anjasha Gangopadhyay (ORCID: https://orcid.org/0000-0002-3884-5637)
- Theophile Jegou du Laz (ORCID: https://orcid.org/0009-0003-6181-4526)
- Tomás Ahumada (ORCID: https://orcid.org/0000-0002-2184-6430)
- Nikolaus Z. Prusinski (ORCID: https://orcid.org/0000-0001-5847-7934)
- Chang Liu (ORCID: https://orcid.org/0000-0002-7866-4531)
- Roger M. Smith (ORCID: https://orcid.org/0000-0001-7062-9726)
- M. M. Kasliwal (ORCID: https://orcid.org/0000-0002-5619-4938)
- Jennifer Shi
- S. Romagnoli (ORCID: https://orcid.org/0009-0003-8153-9576)
Institutions
- Northwestern University (US)
- California Institute of Technology (US)
- University of Minnesota (US)
- Stockholm University (SE)
- University of California, Santa Cruz (US)
- University of Hawaii at Hilo (US)
- ARC Centre of Excellence for Gravitational Wave Discovery (AU)
- AlbaNova (SE)
- Infrared Processing and Analysis Center (US)
- Liverpool John Moores University (GB)
- Drexel University (US)
Publication Details
- Journal
- The Astrophysical Journal
- Published
- 2025-05-29
- DOI
- https://doi.org/10.3847/1538-4357/adcf1e
- Citations
- 7
- Primary Topic
- Gamma-ray bursts and supernovae
- Type
- article
- Field-Weighted Citation Impact
- 8.08
Funders
- David and Lucile Packard Foundation
- U.S. Department of Energy
- National Aeronautics and Space Administration
- Gordon and Betty Moore Foundation
- Illinois Space Grant Consortium
- Villum Fonden
- Heising-Simons Foundation