A study in scarlet

Aims. We investigate the photometric characteristics of a sample 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 reveal the physical origin of such events, thanks to the analysis of the datasets collected. Methods. We present the multi-wavelength photometric follow-up of four ILRTs, namely NGC 300 2008OT-1, AT 2019abn, AT 2019ahd, and AT 2019udc. Through the analysis and modelling of their spectral energy distribution and bolometric light curves, we inferred the physical parameters associated with these transients. Results. All four objects display a single-peaked light curve which ends in a linear decline in magnitudes at late phases. A flux excess with respect to a single blackbody emission is detected in the infrared domain for three objects in our sample, a few months after maximum. This feature, commonly found in ILRTs, is interpreted as a sign of dust formation. Mid-infrared monitoring of NGC 300 2008OT-1 761 days after maximum allowed us to infer the presence of ∼10 −3 –10 −5 M ⊙ of dust, depending on the chemical composition and the grain size adopted. The late-time decline of the bolometric light curves of the considered ILRTs is shallower than expected for 56 Ni decay, hence requiring an additional powering mechanism. James Webb Space Telescope observations of AT 2019abn prove that the object has faded below its progenitor luminosity in the mid-infrared domain, five years after its peak. Together with the disappearance of NGC 300 2008OT-1 in Spitzer images seven years after its discovery, this supports the terminal explosion scenario for ILRTs. With a simple semi-analytical model we tried to reproduce the observed bolometric light curves in the context of a few solar masses ejected at few 10 3 km s −1 and enshrouded in an optically thick circumstellar medium.

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Publication Details

Journal
Astronomy and Astrophysics
Published
2025-02-07
DOI
https://doi.org/10.1051/0004-6361/202451733
Citations
5
Primary Topic
Calibration and Measurement Techniques
Type
article
Field-Weighted Citation Impact
24.97

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article

A study in scarlet

R. Amaro, E. Kankare, T.E Müller-Bravo, J. P. Anderson et al.
5 citations
Astronomy and Astrophysics
Calibration and Measurement Techniques
24.97
article

A study in scarlet

R. Amaro, E. Kankare, T.E Müller-Bravo, J. P. Anderson, S. Brennan, L. Tomasella, G. Pignata, F. Bufano, M. Fraser, M. Lundquist, A. Pastorello, L. Galbany, Raya Dastidar, D.A. Howell, P. Ochner, S. Prentice, G. Valerin, M. Fulton, Rupak Roy, D. Eappachen, K. Misra, Yongzhi Cai, A. Fiore, D. R. Young, C. Pellegrino, D. Hiramatsu, S. Wyatt, S. Benetti, M. Della Valle, S. J. Smartt, Estefania Padilla Gonzalez, A. Reguitti, M. Turatto, M. Stritzinger, T. W. Chen, D. E. Reichart, S. Valenti, A. Rau, 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, G. Leloudas, N. Elias–Rosa, M. Nicholl, Eric Y. Hsiao, Anjasha Gangopadhyay, E. Paraskeva, C. Inserra, J. E. Andrews
article en
5 citations

Abstract

Aims. We investigate the photometric characteristics of a sample 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 reveal the physical origin of such events, thanks to the analysis of the datasets collected. Methods. We present the multi-wavelength photometric follow-up of four ILRTs, namely NGC 300 2008OT-1, AT 2019abn, AT 2019ahd, and AT 2019udc. Through the analysis and modelling of their spectral energy distribution and bolometric light curves, we inferred the physical parameters associated with these transients. Results. All four objects display a single-peaked light curve which ends in a linear decline in magnitudes at late phases. A flux excess with respect to a single blackbody emission is detected in the infrared domain for three objects in our sample, a few months after maximum. This feature, commonly found in ILRTs, is interpreted as a sign of dust formation. Mid-infrared monitoring of NGC 300 2008OT-1 761 days after maximum allowed us to infer the presence of ∼10 −3 –10 −5 M ⊙ of dust, depending on the chemical composition and the grain size adopted. The late-time decline of the bolometric light curves of the considered ILRTs is shallower than expected for 56 Ni decay, hence requiring an additional powering mechanism. James Webb Space Telescope observations of AT 2019abn prove that the object has faded below its progenitor luminosity in the mid-infrared domain, five years after its peak. Together with the disappearance of NGC 300 2008OT-1 in Spitzer images seven years after its discovery, this supports the terminal explosion scenario for ILRTs. With a simple semi-analytical model we tried to reproduce the observed bolometric light curves in the context of a few solar masses ejected at few 10 3 km s −1 and enshrouded in an optically thick circumstellar medium.

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), Institute of Space Sciences (ES), University of Arizona (US), Universidad Andrés Bello (CL), Indian Institute of Astrophysics (IN), Radboud University Nijmegen (NL), University of California, Santa Barbara (US), University of Turku (FI), Stockholm University (SE), Manipal Academy of Higher Education (IN), University of Tarapacá (CL), Chinese Academy of Sciences (CN), Aarhus University (DK), Trinity College Dublin (IE), National Central University (TW), Yunnan Observatories (CN), 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), Yunnan Institute of Environmental Sciences (CN), AlbaNova (SE), Osservatorio Astronomico di Padova (IT), The NSF AI Institute for Artificial Intelligence and Fundamental Interactions (US), Space Research Organisation Netherlands (NL), University of Virginia (US), Liverpool John Moores University (GB), Cardiff University (GB), University of California, Davis (US), Ruhr University Bochum (DE), Technical University of Denmark (DK)
INAF-Osservatorio Astronomico di Padova
Openalex Percentile: Top 1%
Calibration and Measurement Techniques
24.97
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