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AT 2020mot is a typical UV/optical tidal disruption event (TDE) with no radio or X-ray signatures in a quiescent host. We find ani-band excess and rebrightening along the decline of the light curve which could be due to two consecutive dust echoes from the TDE. We model our observations following van Velzen et al. and find that the near-infrared light curve can be explained by concentric rings of thin dust within ∼0.1 pc of a ∼6 × 10⁶M_⊙supermassive black hole (SMBH), among the smallest scales at which dust has been inferred near SMBHs. We find dust covering factors of orderf_c≤ 2%, much lower than found for dusty tori of active galactic nuclei. These results highlight the potential of TDEs for uncovering the environments around black holes when including near-infrared observations in high-cadence transient studies.

 

We present high-cadence optical and ultraviolet (UV) observations of the Type II supernova (SN), SN 2022jox which exhibits early spectroscopic high-ionization flash features of Hi, Heii, Civ, and Nivthat disappear within the first few days after explosion. SN 2022jox was discovered by the Distance Less Than 40 Mpc survey ∼0.75 day after explosion with follow-up spectra and UV photometry obtained within minutes of discovery. The SN reached a peak brightness ofM_V∼ −17.3 mag, and has an estimated⁵⁶Ni mass of 0.04M_⊙, typical values for normal Type II SNe. The modeling of the early light curve and the strong flash signatures present in the optical spectra indicate interaction with circumstellar material (CSM) created from a progenitor with a mass-loss rate of$\dot{M}\sim {10}^{-3}\text{–}{10}^{-2}{M}_{\odot }{\mathrm{y}\mathrm{r}}^{-1}$. There may also be some indication of late-time CSM interaction in the form of an emission line blueward of Hαseen in spectra around 200 days. The mass-loss rate of SN 2022jox is much higher than the values typically associated with quiescent mass loss from red supergiants, the known progenitors of Type II SNe, but is comparable to inferred values from similar core-collapse SNe with flash features, suggesting an eruptive event or a superwind in the progenitor in the months or years before explosion.

 

We present optical, infrared, ultraviolet, and radio observations of SN 2022xkq, an underluminous fast-declining Type Ia supernova (SN Ia) in NGC 1784 (D≈ 31 Mpc), from <1 to 180 days after explosion. The high-cadence observations of SN 2022xkq, a photometrically transitional and spectroscopically 91bg-like SN Ia, cover the first days and weeks following explosion, which are critical to distinguishing between explosion scenarios. The early light curve of SN 2022xkq has a red early color and exhibits a flux excess that is more prominent in redder bands; this is the first time such a feature has been seen in a transitional/91bg-like SN Ia. We also present 92 optical and 19 near-infrared (NIR) spectra, beginning 0.4 days after explosion in the optical and 2.6 days after explosion in the NIR. SN 2022xkq exhibits a long-lived Ci1.0693μm feature that persists until 5 days post-maximum. We also detect Ciiλ6580 in the pre-maximum optical spectra. These lines are evidence for unburnt carbon that is difficult to reconcile with the double detonation of a sub-Chandrasekhar mass white dwarf. No existing explosion model can fully explain the photometric and spectroscopic data set of SN 2022xkq, but the considerable breadth of the observations is ideal for furthering our understanding of the processes that produce faint SNe Ia.

 

ABSTRACT We present early-time (t < +50 d) observations of SN 2019muj (=ASASSN-19tr), one of the best-observed members of the peculiar SN Iax class. Ultraviolet and optical photometric and optical and near-infrared spectroscopic follow-up started from ∼5 d before maximum light [tmax(B) on $58707.8$ MJD] and covers the photospheric phase. The early observations allow us to estimate the physical properties of the ejecta and characterize the possible divergence from a uniform chemical abundance structure. The estimated bolometric light-curve peaks at 1.05 × 1042 erg s−1 and indicates that only 0.031 M⊙ of 56Ni was produced, making SN 2019muj a moderate luminosity object in the Iax class with peak absolute magnitude of $M_\rm {V} = -16.4$ mag. The estimated date of explosion is t0 = $58698.2$ MJD and implies a short rise time of trise = 9.6 d in B band. We fit of the spectroscopic data by synthetic spectra, calculated via the radiative transfer code tardis. Adopting the partially stratified abundance template based on brighter SNe Iax provides a good match with SN 2019muj. However, without earlier spectra, the need for stratification cannot be stated in most of the elements, except carbon, which is allowed to appear in the outer layers only. SN 2019muj provides a unique opportunity to link extremely low-luminosity SNe Iax to well-studied, brighter SNe Iax.