A study in scarlet

Aims. We investigate the spectroscopic characteristics of intermediate-luminosity Red Transients (ILRTs), a class of elusive objects with peak luminosity between that of classical novae and standard supernovae. Our goal is to provide a stepping stone in the path to unveiling the physical origin of these events based on the analysis of the collected datasets. Methods. We present the extensive optical and near-infrared (NIR) spectroscopic monitoring of four ILRTs, namely NGC 300 2008OT-1, AT 2019abn, AT 2019ahd and AT 2019udc. First we focus on the evolution of the most prominent spectral features observed in the low-resolution spectra. We then present a more detailed description of the high-resolution spectrum collected for NGC 300 2008OT-1 with the Very Large Telescope equipped with UVES. Finally, we describe our analysis of late-time spectra of NGC 300 2008OT-1 and AT 2019ahd through comparisons with both synthetic and observed spectra. Results. Balmer and Ca lines dominate the optical spectra, revealing the presence of slowly moving circumstellar medium (CSM) around the objects. The line luminosity of H α , H β , and Ca II NIR triplet presents a double peaked evolution with time, possibly indicative of interaction between fast ejecta and the slow CSM. The high-resolution spectrum of NGC 300 2008OT-1 reveals a complex circumstellar environment, with the transient being surrounded by a slow (∼30 km s −1 ) progenitor wind. At late epochs, optical spectra of NGC 300 2008OT-1 and AT 2019ahd show broad (∼2500 km s −1 ) emission features at ∼6170 Å and ∼7000 Å which are unprecedented for ILRTs. We find that these lines originate most likely from the blending of several narrow lines, possibly of iron-peak elements.

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Publication Details

Journal
Astronomy and Astrophysics
Published
2025-02-07
DOI
https://doi.org/10.1051/0004-6361/202451735
Citations
4
Primary Topic
Spectroscopy and Laser Applications
Type
article
Field-Weighted Citation Impact
3.03

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article

A study in scarlet

E. Kankare, T.E Müller-Bravo, J. P. Anderson, S. Brennan et al.
4 citations
Astronomy and Astrophysics
Spectroscopy and Laser Applications
3.03
article

A study in scarlet

E. Kankare, T.E Müller-Bravo, J. P. Anderson, S. Brennan, L. Tomasella, A. Pastorello, N. Elias-Rosa, G. Pignata, Marco Limongi, P. Lundqvist, F. Bufano, M. Fraser, M. Lundquist, L. Galbany, Raya Dastidar, D.A. Howell, P. Ochner, S. Prentice, G. Valerin, M. Gromadzki, Rupak Roy, D. Eappachen, K. Misra, M. D. Fulton, Yongzhi Cai, A. Fiore, J. Sollerman, D. R. Young, R. C. Amaro, C. Pellegrino, D. Hiramatsu, S. Wyatt, S. Benetti, M. Della Valle, S. J. Smartt, Estefania Padilla Gonzalez, E. Mason, A. Reguitti, M. Turatto, M. Stritzinger, T. W. Chen, D. E. Reichart, S. Valenti, A. Rau, C. Barbarino, E. Cappellaro, Mridweeka Singh, R. Kotak, J. Jencson, P. A. Mazzali, Tim Reynolds, L. Tartaglia, T. Heikkilä, I. Salmaso, C. McCully, H. Kuncarayakti, E. Karamehmetoglu, Luca Izzo, D. J. Sand, E. Callis, Melissa Shahbandeh, G. Leloudas, M. Nicholl, Eric Y. Hsiao, Anjasha Gangopadhyay, E. Paraskeva, C. Inserra, J. E. Andrews
article en
4 citations

Abstract

Aims. We investigate the spectroscopic characteristics of intermediate-luminosity Red Transients (ILRTs), a class of elusive objects with peak luminosity between that of classical novae and standard supernovae. Our goal is to provide a stepping stone in the path to unveiling the physical origin of these events based on the analysis of the collected datasets. Methods. We present the extensive optical and near-infrared (NIR) spectroscopic monitoring of four ILRTs, namely NGC 300 2008OT-1, AT 2019abn, AT 2019ahd and AT 2019udc. First we focus on the evolution of the most prominent spectral features observed in the low-resolution spectra. We then present a more detailed description of the high-resolution spectrum collected for NGC 300 2008OT-1 with the Very Large Telescope equipped with UVES. Finally, we describe our analysis of late-time spectra of NGC 300 2008OT-1 and AT 2019ahd through comparisons with both synthetic and observed spectra. Results. Balmer and Ca lines dominate the optical spectra, revealing the presence of slowly moving circumstellar medium (CSM) around the objects. The line luminosity of H α , H β , and Ca II NIR triplet presents a double peaked evolution with time, possibly indicative of interaction between fast ejecta and the slow CSM. The high-resolution spectrum of NGC 300 2008OT-1 reveals a complex circumstellar environment, with the transient being surrounded by a slow (∼30 km s −1 ) progenitor wind. At late epochs, optical spectra of NGC 300 2008OT-1 and AT 2019ahd show broad (∼2500 km s −1 ) emission features at ∼6170 Å and ∼7000 Å which are unprecedented for ILRTs. We find that these lines originate most likely from the blending of several narrow lines, possibly of iron-peak elements.

Astronomy and AstrophysicsVol. 695
University College Dublin (IE), Florida State University (US), Hiroshima University (JP), University of North Carolina at Chapel Hill (US), Goethe University Frankfurt (DE), California Institute of Technology (US), University of Copenhagen (DK), Queen's University Belfast (GB), Las Cumbres Observatory Global Telescope Network (US), Space Telescope Science Institute (US), Institute of Space Sciences (ES), University of Arizona (US), Universidad Andrés Bello (CL), Indian Institute of Astrophysics (IN), Johns Hopkins University (US), Radboud University Nijmegen (NL), University of California, Santa Barbara (US), University of Turku (FI), Stockholm University (SE), Manipal Academy of Higher Education (IN), Kavli Institute for the Physics and Mathematics of the Universe (JP), University of Tarapacá (CL), Chinese Academy of Sciences (CN), Aarhus University (DK), Trinity College Dublin (IE), National Central University (TW), Astronomical Observatory of Rome (IT), Yunnan Observatories (CN), Trieste Astronomical Observatory (IT), Astronomical Observatory of Capodimonte (IT), Brera Astronomical Observatory (IT), Aryabhatta Research Institute of Observational Sciences (IN), University of Oxford (GB), Max Planck Institute for Extraterrestrial Physics (DE), Institut d'Estudis Espacials de Catalunya (ES), Istituto Nazionale di Fisica Nucleare, Trento Institute for Fundamental Physics And Applications (IT), Millennium Institute of Astrophysics (CL), Queens University (BD), Max Planck Institute for Astrophysics (DE), DAWN Center for Independent Living (US), National Observatory of Athens (GR), Osservatorio Astrofisico di Catania (IT), International Center for Relativistic Astrophysics (IT), Center for Astrophysics Harvard & Smithsonian (US), Collurania Teramo Observatory (IT), European Southern Observatory (CL), AlbaNova (SE), Osservatorio Astronomico di Padova (IT), The NSF AI Institute for Artificial Intelligence and Fundamental Interactions (US), Istituto Nazionale di Fisica Nucleare, Sezione di Perugia (IT), Infrared Processing and Analysis Center (US), University of Warsaw (PL), Space Research Organisation Netherlands (NL), University of Virginia (US), Liverpool John Moores University (GB), The University of Tokyo (JP), Cardiff University (GB), University of California, Davis (US), National Institute for Astrophysics (IT), Ruhr University Bochum (DE), Technical University of Denmark (DK)
National Natural Science Foundation of China, INAF-Osservatorio Astronomico di Padova
Openalex Percentile: Top 10%
Spectroscopy and Laser Applications
3.03
DOIOpen Access PDFOpenAlex
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