Journal ArticleCharacterizing the Ordinary Broad-line Type Ic SN 2023pel from the Energetic GRB 230812BSrinivasaragavan, Gokul P; Swain, Vishwajeet; O’Connor, Brendan; Anand, Shreya; Ahumada, Tomás; Perley, Daniel; Stein, Robert; Sollerman, Jesper; Fremling, Christoffer; Cenko, S Bradley; Antier, S; Guessoum, Nidhal; Hussenot-Desenonges, Thomas; Hello, Patrice; Lesage, Stephen; Hammerstein, Erica; Miller, M Coleman; Andreoni, Igor; Bhalerao, Varun; Bloom, Joshua S; Dutta, Anirban; Gal-Yam, Avishay; Hinds, K-Ryan; Jaodand, Amruta; Kasliwal, Mansi; Kumar, Harsh; Kutyrev, Alexander S; Ragosta, Fabio; Ravi, Vikram; Sharma, Kritti; Singh_Teja, Rishabh; Yang, Sheng; Anupama, G C; Bellm, Eric C; Coughlin, Michael W; Mahabal, Ashish A; Masci, Frank J; Pathak, Utkarsh; Purdum, Josiah; Roberts, Oliver J; Smith, Roger; Wold, Avery<title>Abstract</title> <p>We report observations of the optical counterpart of the long gamma-ray burst (GRB) GRB 230812B and its associated supernova (SN) SN 2023pel. The proximity (<italic>z</italic>= 0.36) and high energy (<italic>E</italic>_{<italic>γ</italic>,iso}∼ 10⁵³erg) make it an important event to study as a probe of the connection between massive star core collapse and relativistic jet formation. With a phenomenological power-law model for the optical afterglow, we find a late-time flattening consistent with the presence of an associated SN. SN 2023pel has an absolute peak<italic>r</italic>-band magnitude of<italic>M</italic>_{<italic>r</italic>}= −19.46 ± 0.18 mag (about as bright as SN 1998bw) and evolves on quicker timescales. Using a radioactive heating model, we derive a nickel mass powering the SN of<italic>M</italic>_Ni= 0.38 ± 0.01<italic>M</italic>_⊙and a peak bolometric luminosity of<italic>L</italic>_bol∼ 1.3 × 10⁴³erg s⁻¹. We confirm SN 2023pel’s classification as a broad-line Type Ic SN with a spectrum taken 15.5 days after its peak in the<italic>r</italic>band and derive a photospheric expansion velocity of<italic>v</italic>_ph= 11,300 ± 1600 km s⁻¹at that phase. Extrapolating this velocity to the time of maximum light, we derive the ejecta mass<italic>M</italic>_ej= 1.0 ± 0.6<italic>M</italic>_⊙and kinetic energy<inline-formula><tex-math><CDATA/></tex-math><math overflow='scroll'><msub><mrow><mi>E</mi></mrow><mrow><mi>KE</mi></mrow></msub><mo>=</mo><msubsup><mrow><mn>1.3</mn></mrow><mrow><mo>−</mo><mn>1.2</mn></mrow><mrow><mo>+</mo><mn>3.3</mn></mrow></msubsup><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mn>51</mn></mrow></msup><mspace width='0.25em'/><mi>erg</mi></math><inline-graphic href='apjlad16e7ieqn1.gif' type='simple'/></inline-formula>. We find that GRB 230812B/SN 2023pel has SN properties that are mostly consistent with the overall GRB-SN population. The lack of correlations found in the GRB-SN population between SN brightness and<italic>E</italic>_{<italic>γ</italic>,iso}for their associated GRBs across a broad range of 7 orders of magnitude provides further evidence that the central engine powering the relativistic ejecta is not coupled to the SN powering mechanism in GRB-SN systems.</p>AAS2024-01-0110578328The Astrophysical Journal Letters9602L182041-8205https://doi.org/10.3847/2041-8213/ad16e72034437National Science Foundation