J/A+A/711/A262 Photometric observations of SN 2024igg (Liu+, 2026)
SN 2024igg: A Super-Chandrasekhar/03fg-like SN exhibiting C II-dominated
spectra after explosion.
Liu J., Wang X., Chen L., Filippenko A.V., Brink T.G., Zheng W.,
Pastorello A., Ochner P., Albanese I., Reguitti A., Valerin G.,
Cai Y., Zhang J., Li L., Wang Z., Liu L., Zhang Y.
<Astron. Astrophys. 711, A262 (2026)>
=2026A&A...711A.262L 2026A&A...711A.262L (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae ; Photometry ; Optical ; Ultraviolet
Keywords: supernovae: general - supernovae: individual: SN 2024igg
Abstract:
We present and analyze photometric and spectroscopic observations of
the Type Ia supernova (SN Ia) 2024igg, another super-Chandrasekhar (or
03fg-like) SN whose strong CIIλ6580 feature was initially
misidentified as Hα, thereby constraining its progenitor system,
explosion parameters, and physical scenario.
We conducted a comparative analysis of SN 2024igg and other 03fg-like
SNe. The radiative-transfer code TARDIS was run to identify the
features in the first spectrum at t~-13.9 days. A pseudo-bolometric
light curve was constructed using ultraviolet and optical photometry
and was then modeled with fitting tools.
SN 2024igg shows many characteristics in common with other 03fg-like
objects, such as high ultraviolet flux, slowly declining light curves
({DELTA}m15(B)=0.90±0.08mag), low expansion velocities, and strong
and persistent CII absorption. On the other hand, it exhibits some
remarkable properties within this subgroup, including a moderately low
optical luminosity (Mmax(B)=-18.99±0.15mag), a rise time shorter
than 18.5 days, and the strongest CIIλ6580 ever detected. The
bolometric analysis yields a 56Ni mass of MNi=0.547±.082M☉
and an ejecta mass of 1.54+0.22-0.19M☉, which marginally
exceeds the Chandrasekhar mass. Our TARDIS result indicates that most
of the features in the earliest spectrum might be attributed to CII,
which is consistent with a model in which an SN explodes within a
carbon-rich circumstellar medium (CSM). The CSM interaction would
produce a density peak in the ejecta, offering a natural explanation
for the slowly evolving line velocities near ∼8000km/s. The CSM may
stem from the debris of a secondary white dwarf in a white dwarf
merger or the envelope of an asymptotic giant branch star. Combined
with the unshifted forbidden lines in the spectrum taken at t~+135
days, we suggest that SN 2024igg comes from a symmetric explosion on a
secular timescale after the merger.
Description:
This catalogue contains ultraviolet and optical photometric
observations of SN 2024igg.
Photometry is provided in UVW1, UVW2, UVM2, U, B, V, g, r, and i
bands.
Objects:
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RA (2000) DE Designation(s)
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15 09 30.910 +54 30 20.24 SN 2024igg
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea2.dat 36 316 Photometric observations of SN 2024igg
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
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1- 9 F9.3 d MJD Modified Julian Date, JD-2400000.5
11- 16 F6.3 mag mag Observed apparent magnitude in Filter
18- 22 F5.3 mag e_mag Uncertainty of the magnitude measurement
24- 27 A4 --- Filter Photometric filter used for the observation (1)
29- 36 A8 --- Source Source of the photometry
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Note (1): Filters are UBV, gri, UVM2 UVW1 UVW2.
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Acknowledgements:
Jialian Liu, liu-jl22(at)mails.tsinghua.edu.cn
License: CC-BY-4.0
(End) Patricia Vannier [CDS] 04-Jun-2026