J/A+A/702/A212 SN 2021irp photometry (Reynolds+, 2025)
The bright long-lived Type II SN 2021irp powered by aspherical circumstellar
material interaction.
I. Revealing the energy source with photometry and spectroscopy.
Reynolds T.M., Nagao T., Gottumukkala R., Gutierrez C.P., Kangas T.,
Kravtsov T., Kuncarayakti H., Maeda K., Elias-Rosa N., Fraser M., Kotak R.,
Mattila S., Pastorello A., Pessi P.J., Cai Y.-Z., Fynbo J.P.U., Kawabata M.,
Lundqvist P., Matilainen K., Moran S., Reguitti A., Taguchi K., Yamanaka M.
<Astron. Astrophys. 702, A212 (2025)>
=2025A&A...702A.212R 2025A&A...702A.212R (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae ; Photometry ; Optical
Keywords: supernovae: general - supernovae: individual: SN 2021irp
Abstract:
Some core-collapse supernovae (CCSNe) are too luminous and radiate too
much total energy to be powered by the release of thermal energy from
the ejecta and radioactive-decay energy from the synthesised
56Ni/56Co. A source of additional power is the interaction between
the supernova (SN) ejecta and a massive circumstellar material (CSM).
This is an important power source in Type IIn SNe, which show narrow
spectral lines arising from the unshocked CSM, but not all interacting
SNe show such narrow lines. We present photometric and spectroscopic
observations of the hydrogen-rich SN 2021irp, which is both luminous,
with Mo←19.4mag, and long-lived, remaining brighter than
Mo=-18mag for ∼250d. We show that an additional energy source is
required to power such a SN, and determine the nature of the source.
We also investigate the properties of the pre-existing and newly
formed dust associated with the SN. Photometric observations show that
the luminosity of the SN is an order of magnitude higher than typical
Type II SNe and persists for much longer. We detect a infrared excess
attributed to dust emission. Spectra show multi-component line
profiles, an Fe II pseudo-continuum, and a lack of absorption lines,
all typical features of Type IIn SNe. We detect a narrow (<85km/s)
P-Cygni profile associated with the unshocked CSM. An asymmetry in
emission line profiles indicates dust formation occurring from
250-300d. Analysis of the SN blackbody radius evolution indicates
asymmetry in the shape of the emitting region. We identify the main
power source of SN 2021irp as extensive interaction with a massive
CSM, and that this CSM is distributed asymmetrically around the
progenitor star. The infrared excess is explained with emission from
newly formed dust although there is also some evidence of an IR echo
from pre-existing dust at early times.
Description:
Photometry of SN 2021irp. Photometry in ATLAS co and SDSS riz bands is
presented in the AB system, while the remaining photometry is
presented in the Vega system. Values are not corrected for extinction.
Phases are in rest frame days with respect to our estimated explosion
epoch.
Objects:
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RA (2000) DE Designation(s)
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05 23 27.45 +17 04 39.8 SN 2021irp = ATLAS 21lhv
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 41 178 Photometry of SN 2021irp
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See also:
J/A+A/702/A213 : SN 2021irp polarisation spectra (Reynolds+, 2025)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 6 F6.2 d Phase Phase (rest frame days with respect to our
estimated explosion epoch)
8- 15 F8.2 d MJD Modified Julian date
17 A1 --- l_mag Limit flag on mag
18- 22 F5.2 mag mag Magnitude in Band (1)
24- 27 F4.2 mag e_mag ?=- Magnitude in Band error
29- 30 A2 --- Band [G BVJHK riz co W1 W2] Observed band
32- 41 A10 --- Tel+Inst Telescope
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Note (1): Photometry in ATLAS co and SDSS riz bands is presented in the AB
system, while the remaining photometry is presented in the Vega system.
Values are not corrected for extinction.
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Acknowledgements:
Thomas Reynolds (thmire(at)utu.fi) produced the photometry, and
uploaded the data to CDS.
References:
Reynolds et al., Paper II 2025A&A...702A.213R 2025A&A...702A.213R, Cat. J/A+A/702/A213
(End) Patricia Vannier [CDS] 19-Sep-2025