Photometric and Spectroscopic Studies of Type Ic Supernovae SN 2020akf and SN 2021mxx

Mulchand Kurre; K. R. Sahu; Shrutika Tiwari; Yogita Patel; N. K. Chakradhari; D. K. Sahu; Rishabh Singh Teja; G. C. Anupama; Mridweeka Singh; Anirban Dutta; Anjasha Gangopadhyay

arXiv · 2607.12525

Photometric and Spectroscopic Studies of Type Ic Supernovae SN 2020akf and SN 2021mxx

Mulchand Kurre·K. R. Sahu·Shrutika Tiwari·Yogita Patel·N. K. Chakradhari·D. K. Sahu·Rishabh Singh Teja·G. C. Anupama·Mridweeka Singh·Anirban Dutta·Anjasha Gangopadhyay

View original source ↗Read source document ↗Export metadata ↓

Abstract

We present a comprehensive analysis of optical photometry and medium-resolution spectroscopy for Type Ic supernovae (SNe) SN 2020akf and SN 2021mxx. Our study covers the evolution of SN 2020akf from -5 to 109 days and SN 2021mxx from -3 to 115 days relative to their B-band maximum. Their peak quasi-bolometric luminosities are estimated at logL_bol = 42.37 +- 0.02 and 42.21 +- 0.02 erg/s, respectively. The velocities of the ejecta, derived from the Fe II 5169 A line at maximum light, are approximately 15000 km/s for SN~2020akf and about 10000 km/s for SN~2021mxx, which are consistent with those observed in other Type~Ic SNe. Using the semianalytical Arnett model, we estimate that SN 2020akf has a kinetic energy of E_k = 6.33 (+0.68)(-0.62) x 10^51 erg and an ejected mass of M_ej = 4.71 (+0.50)(-0.46) M_sun, while for SN 2021mxx, we get E_k = 0.54 (+0.08)(-0.12) x 10^51 erg and M_ej = 0.90 (+0.14)(-0.18),M_sun. The mass of Ni56 synthesized in the explosion is estimated at 0.10 +- 0.02 M_sun for SN 2020akf and 0.05 +- 0.01 M_sun for SN 2021mxx. The metallicities of the host galaxies near the SN regions are ~0.81 Z_sun for SN 2020akf and ~0.76 Z_sun for SN 2021mxx, where Z_sun indicates solar metallicity. Our detailed analysis suggests that SN 2020akf falls into the category of a transitional Type Ic SN, having spectral properties between normal and broad-line Type Ic SNe, while SN 2021mxx is a normal Type Ic SN with an extremely low value of the M_ej / E_k ratio.

Explore related subjects

astro-ph.HE astro-ph.SR

Keep this discovery

BibTeX RIS

Mulchand Kurre, K. R. Sahu, Shrutika Tiwari, Yogita Patel, N. K. Chakradhari, D. K. Sahu, Rishabh Singh Teja, G. C. Anupama, Mridweeka Singh, Anirban Dutta, Anjasha Gangopadhyay. 2026-07-14. Photometric and Spectroscopic Studies of Type Ic Supernovae SN 2020akf and SN 2021mxx. https://arxiv.org/abs/2607.12525

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

IceCube neutrino point-source searches in the direction of the KM3NeT ultra-high-energy event

While still under construction, the KM3NeT Astroparticle Research with Cosmics in the Abyss (ARCA) detector recorded a $\sim$200 PeV neutrino on February 13th, 2023. This event is the highest-energy neutrino reported. IceCube, a cubic kilometer neutrino detector located at the geographic South Pole, has previously detected neutrinos up to approximately 10 PeV. We search for high-energy neutrinos from the location of the KM3NeT event using 15 years of IceCube data and considering three temporal hypotheses: steady or flaring in time coincidence, or at an arbitrary time. We find no evidence for neutrino emission for any of the studies performed. Correspondingly, we set upper limits on the neutrino flux from a point source in the direction of KM3-230213A. We compare these limits to KM3NeT's estimated flux and show that an astrophysical explanation of this event is strongly constrained for a variety of spectral assumptions for a steady or transient point source with the flux inferred from the single KM3NeT ultra-high-energy event assuming a spectral index of 2.0.

astro-ph.HE↗

arXiv2026

Evidence for the binary nature of the long-period radio transient ASKAP/DART J1832-0911

Long-period transients are a class of periodic pulsed radio source repeating on the minute to hour timescale. Recently, an increasing number of them are being identified as binary systems, specifically white dwarfs with low-mass main-sequence companions. In this work we analyse the most luminous long-period transient discovered to date, ASKAP/DART J1832-0911, with two years of radio data, and propose that it, too, may be a white dwarf system, although in a far more compact orbit than the aforementioned. The pulses are composed of quasi-periodic components which evolve in a systematic way over days and months. The source is highly linearly or elliptically polarised and its brightness enabled very high signal-to-noise measurement of the time-resolved Faraday rotation measure, which was found to vary across pulse phase. The linear polarisation position angle, circular polarised fraction, and spectral index also varied systematically in ways not typical of pulsars and magnetars. We show that an ultra-compact asynchronous polar explains much of the phenomenology of ASKAP/DART J1832-0911, in particular the evolution of the pulse morphology, rotation measure variation, and periodic X-ray emission, although we cannot conclusively prove a binary nature. However, our model makes testable predictions.

astro-ph.HE↗

arXiv2026

Nonbirefringent model of orthogonal polarization modes in radio pulsars - New view on S swing and mode structure in pulsar beam

Two orthogonal polarization modes observed in radio pulsar signals have long been attributed to proper modes of wave oscillation in strongly magnetized plasma. Yet it has been shown recently that they show up readily for extended emission regions that produce incoherently-superposed polarization signal. In this paper we present a two-dimensional polarization model based on incoherent superposition of radio signals. The model involves a single proper mode, say the O mode, but leads to the appearance of two orthogonal polarization tracks and naturally produces the triple form of polarization mode segregation in averaged profiles (central mode flanked on boths sides by another mode), as well as the displacement of modes in latitude, previously inferred from beam mapping. In the case of conal emission regions, the modelled polarization tends to mimic general polarization properties of the rotating vector model (RVM). However, the reason for this is the symmetry of the emission region - not the usual projection of dipolar magnetic azimuths. Thus the emerging RVM parameters reveal geometry of the emission region, not of the dipolar magnetic field. The results strongly support the vital role of nonbirefringent modal effects in radio pulsar profiles. Two proper modes may not be needed to explain observations of two orthogonal polarization tracks.

astro-ph.HE↗