A&A, 686, A79 (2024)
M. D. Stritzinger1, E. Baron2,3, F. Taddia1, C. R. Burns4, M. Fraser5, L. Galbany6,7, S. Holmbo1, P. Hoeflich8, N. Morrell9, L. S. Arndt1, E. Y. Hsiao8, J. P. Johansson10, E. Karamehmetoglu1, H. Kuncarayakti11, J. Lyman12, T. J. Moriya13,14, K. Phan1,6, M. M. Phillips9, J. P. Anderson15, C. Ashall16, P. J. Brown17, S. Castellón9, M. Della Valle18,19, S. González-Gaitán20, M. Gromadzki21, R. Handberg1, J. Lu22, M. Nicholl23 and M. Shahbandeh24,25
1 Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark
e-mail: max@phys.au.dk
2 Planetary Science Institute, 1700 E Fort Lowell Rd., Ste 106, Tucson, AZ 85719, USA
3 Hamburger Sternwarte, Gojensbergweg 112, 21029 Hamburg, Germany
4 Observatories of the Carnegie Institution for Science, 813 Santa Barbara St., Pasadena, CA 91101, USA
5 School of Physics, O’Brien Centre for Science North, University College Dublin, Belfield, Dublin 4, Ireland
6 Institute of Space Sciences (ICE, CSIC), Campus UAB, Carrer de Can Magrans, s/n, 08193 Barcelona, Spain
7 Institut d’Estudis Espacials de Catalunya (IEEC), 08034 Barcelona, Spain
8 Department of Physics, Florida State University, 77 Chieftain Way, Tallahassee, FL 32306, USA
9 Carnegie Observatories, Las Campanas Observatory, Casilla 601, La Serena, Chile
10 The Oskar Klein Centre, Department of Physics, Stockholm University, AlbaNova, 10691 Stockholm, Sweden
11 Tuorla Observatory, Department of Physics and Astronomy, 20014 Turku, Finland
12 Department of Physics, University of Warwick, Coventry CV4 7AL, UK
13 National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
14 School of Physics and Astronomy, Faculty of Science, Monash University, Clayton, Victoria 3800, Australia
15 European Southern Observatory, Alonso de Córdova 3107, Casilla 19, Santiago, Chile
16 Department of Physics, Virginia Tech, Blacksburg, VA 24061, USA
17 George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A&M University, College Station, TX 77843, USA
18 INAF – Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, 80131 Napoli, Italy
19 Department of Physics, Ariel University, Ariel, Israel
20 CENTRA-Centro de Astrofísica e Gravitacao and Departamento de Fisica, Instituto Superior Tecnico, Universidade de Lisboa, Avenida Rovisco Pais, 1049-001 Lisboa, Portugal
21 Astronomical Observatory, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warszawa, Poland
22 Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA
23 Astrophysics Research Centre, School of Mathematics and Physics, Queens University Belfast, Belfast BT7 1NN, UK
24 Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA
25 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
Received: 4 September 2023
Accepted: 11 March 2024
We present a comprehensive data set of supernova (SN) 2016adj located within the central dust lane of Centaurus A. SN 2016adj is significantly reddened and after correcting the peak apparent B-band magnitude (mB = 17.48 ± 0.05) for Milky Way reddening and our inferred host-galaxy reddening parameters (i.e., RVhost = 5.7±0.7 and AVhost = 6.3 ± 0.2 mag), we estimated it reached a peak absolute magnitude of MB ∼ −18. A detailed inspection of the optical and near-infrared (NIR) spectroscopic time series reveals a carbon-rich SN Ic and not a SN Ib/IIb as previously suggested in the literature. The NIR spectra show prevalent carbon-monoxide formation occurring already by +41 days past B-band maximum, which is ≈11 days earlier than previously reported in the literature for this object. Interestingly, around two months past maximum, the NIR spectrum of SN 2016adj begins to exhibit H features, with a +97 days medium resolution spectrum revealing both Paschen and Bracket lines with absorption minima of ∼2000 km s−1, full-width-half-maximum emission velocities of ∼1000 km s−1, and emission line ratios consistent with a dense emission region. We speculate that these attributes are due to a circ*mstellar interaction (CSI) between the rapidly expanding SN ejecta and a H-rich shell of material that formed during the pre-SN phase. A bolometric light curve was constructed and a semi-analytical model fit suggests the SN synthesized 0.5 M⊙ of 56Ni and ejected 4.7 M⊙ of material, though these values should be approached with caution given the large uncertainties associated with the adopted reddening parameters and known light echo emission. Finally, inspection of the Hubble Space Telescope archival data yielded no progenitor detection.
Key words: supernovae: general / supernovae: individual: 2016adj
Photometry (Table A.3) is available at the CDS via anonymous ftp to cdsarc.cds.unistra.fr (130.79.128.5) or via https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/686/A79
Spectra presented in this paper are available on https://www.wiserep.org/ ().
