Extended Shock Breakout and Early Circumstellar Interaction in SN 2024ggi uri icon

abstract

  • Abstract We present high-cadence photometric and spectroscopic observations of supernova (SN) 2024ggi, a Type II SN with flash spectroscopy features, which exploded in the nearby galaxy NGC 3621 at 7 Mpc. The light-curve evolution over the first 30 hr can be fit by two power-law indices with a break after 22 hr, rising from M V 12.95 mag at +0.66 day to M V 17.91 mag after 7 days. In addition, the densely sampled color curve shows a strong blueward evolution over the first few days and then behaves as a normal SN II with a redward evolution as the ejecta cool. Such deviations could be due to interaction with circumstellar material (CSM). Early high- and low-resolution spectra clearly show high-ionization flash features from the first spectrum to +3.42 days after the explosion. From the high-resolution spectra, we calculate the CSM velocity to be 37 4 km s1. We also see the line strength evolve rapidly from 1.22 to 1.49 days in the earliest high-resolution spectra. Comparison of the low-resolution spectra with CMFGEN models suggests that the pre-explosion mass-loss rate of SN 2024ggi falls in the range of 103102 M yr1, which is similar to that derived for SN 2023ixf. However, the rapid temporal evolution of the narrow lines in the spectra of SN 2024ggi (R CSM 2.7 1014 cm) could indicate a smaller spatial extent of the CSM than in SN 2023ixf (R CSM 5.4 1014 cm), which in turn implies a lower total CSM mass for SN 2024ggi.

published proceedings

  • The Astrophysical Journal Letters

author list (cited authors)

  • Shrestha, M., Bostroem, K. A., Sand, D. J., Hosseinzadeh, G., Andrews, J. E., Dong, Y., ... Gutirrez, C. P.

complete list of authors

  • Shrestha, Manisha||Bostroem, K Azalee||Sand, David J||Hosseinzadeh, Griffin||Andrews, Jennifer E||Dong, Yize||Hoang, Emily||Janzen, Daryl||Pearson, Jeniveve||Jencson, Jacob E||Lundquist, MJ||Mehta, Darshana||Ravi, Aravind P||Retamal, Nicolás Meza||Valenti, Stefano||Brown, Peter J||Jha, Saurabh W||Macrie, Colin||Hsu, Brian||Farah, Joseph||Howell, D Andrew||McCully, Curtis||Newsome, Megan||Gonzalez, Estefania Padilla||Pellegrino, Craig||Terreran, Giacomo||Kwok, Lindsey||Smith, Nathan||Schwab, Michaela||Martas, Aidan||Munoz, Ricardo R||Medina, Gustavo E||Li, Ting S||Diaz, Paula||Hiramatsu, Daichi||Tucker, Brad E||Wheeler, JC||Wang, Xiaofeng||Zhai, Qian||Zhang, Jujia||Gangopadhyay, Anjasha||Yang, Yi||Gutiérrez, Claudia P