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We present near-IR (NIR) and optical observations of the Type Ic supernova (SN Ic) SN 2020oi in the galaxy M100 and the broad-lined SN Ic SN 2020bvc in UGC 9379, using Gemini, Las Cumbres Observatory, Southern Astrophysical Telescope, and other ground-based telescopes. The NIR spectrum of SN 2020oi at day 63 since the explosion shows strong CO emissions and a rising K-band continuum, which is the first unambiguous dust detection from an SN Ic. Non-LTE CO modeling shows that CO is still optically thick and that the lower limit to the CO mass is 10−3M⊙. The dust temperature is 810 K, and the dust mass is ∼10−5M⊙. We explore the possibilities that the dust is freshly formed in the ejecta, heated dust in the preexisting circumstellar medium, and an infrared echo. The light curves of SN 2020oi are consistent with a STELLA model with canonical explosion energy, 0.07 M⊙ Ni mass, and 0.7 M⊙ ejecta mass. A model of high explosion energy of 1052 erg, 0.4 M⊙ Ni mass, and 6.5 M⊙ ejecta mass with the circumstellar matter reproduces the double-peaked light curves of SN 2020bvc. We observe temporal changes of absorption features of the IR Ca ii triplet, S i at 1.043 μm, and Fe ii at 5169 Å. The blueshifted lines indicate high velocities, up to 60,000 km s−1 for SN 2020bvc and 20,000 km s−1 for SN 2020oi, and the expansion velocity rapidly declines before the optical maximum. We present modeled spectral signatures and diagnostics of CO and SiO molecular bands between 1.4 and 10 μm. [ABSTRACT FROM AUTHOR]

We search for far-infrared (FIR) counterparts of known supernova remnants (SNRs) in the Galactic plane (360° in longitude and |$b = \pm \, 1^{\circ }$|⁠) at 70–500  μ m with Herschel. We detect dust signatures in 39 SNRs out of 190, made up of 13 core-collapse supernovae (CCSNe), including 4 Pulsar Wind Nebulae (PWNe), and 2 Type Ia SNe. A further 24 FIR detected SNRs have unknown types. We confirm the FIR detection of ejecta dust within G350.1−0.3, adding to the known sample of ∼ 10 SNRs containing ejecta dust. We discover dust features at the location of a radio core at the centre of G351.2+0.1, indicating FIR emission coincident with a possible Crab-like compact object, with dust temperature and mass of Td  = 45.8 K and Md  = 0.18 M⊙, similar to the PWN G54.1+0.3. We show that the detection rate is higher among young SNRs. We produce dust temperature maps of 11 SNRs and mass maps of those with distance estimates, finding dust at temperatures |$15\, \lesssim \, T_d\, \lesssim \, 40$|  K. If the dust is heated by shock interactions the shocked gas must be relatively cool and/or have a low density to explain the observed low grain temperatures. [ABSTRACT FROM AUTHOR]

We search for far-infrared counterparts of known supernova remnants (SNRs) in the Galactic plane (10° < | l | < 60°) at 70–500 μm using the Herschel Infrared Galactic Plane Survey (Hi-GAL). Of 71 sources studied, we find that 29 (41   per cent) SNRs have a clear FIR detection of dust emission associated with the SNR. Dust from 8 of these is in the central region, and 4 indicate pulsar wind nebulae (PWNe) heated ejecta dust. A further 23 have dust emission in the outer shell structures which is potentially related to swept-up material. Many Galactic SNe have dust signatures but we are biased towards detecting ejecta dust in young remnants and those with a heating source (shock or PWN). We estimate the dust temperature and mass contained within three PWNe, G11.2–0.3, G21.5–0.9, and G29.7–0.3, using modified blackbody fits. To more rigorously analyse the dust properties at various temperatures and dust emissivity index β, we use point process mapping (PPMAP). We find significant quantities of cool dust (at 20–40 K) with dust masses of M d  =  0.34 ± 0.14 M⊙, M d  =  0.29 ± 0.08 M⊙, and M d  =  0.51 ± 0.13 M⊙ for G11.2–0.3, G21.5–0.9, and G29.7–0.3, respectively. We derive the dust emissivity index for the PWN ejecta dust in G21.5–0.3 to be |$\beta \, =\, 1.4 \pm 0.5$| compared to dust in the surrounding medium where |$\beta \, =\, 1.8 \pm 0.1$|⁠. [ABSTRACT FROM AUTHOR]

We present near-infrared spectroscopy of the NGC 5128 supernova SN 2016adj in the first two months following discovery. We report the detection of first-overtone carbon monoxide emission at ∼58.2 d after discovery, one of the earliest detections of CO in an erupting supernova. We model the CO emission to derive the CO mass, temperature, and velocity, assuming both pure 12CO and a composition that includes 13CO; the case for the latter is the isotopic analyses of meteoritic grains, which suggest that core-collapse supernovae can synthesize significant amounts of 13C. Our models show that, while the CO data are adequately explained by pure 12CO, they do not preclude the presence of 13CO, to a limit of 12C/13C > 3, the first constraint on the 12C/13C ratio determined from near-infrared observations. We estimate the reddening to the object, and the effective temperature from the energy distribution at outburst. We discuss whether the ejecta of SN 2016adj may be carbon-rich, what the infrared data tell us about the classification of this supernova, and what implications the early formation of CO in supernovae may have for CO formation in supernovae in general. [ABSTRACT FROM AUTHOR]

We present infrared (IR) and submillimetre observations of the Crab-like supernova remnant (SNR) G54.1+0.3 including 350 $$\mu$$ m (SHARC-II), 870 $$\mu$$ m (LABOCA), 70, 100, 160, 250, 350, and 500  $$\mu$$ m (Herschel), and 3–40  $$\mu$$ m (Spitzer). We detect dust features at 9, 11, and 21  $$\mu$$ m and a long-wavelength continuum dust component. The 21  $$\mu$$ m dust coincides with [Ar  ii ] ejecta emission, and the feature is remarkably similar to that in Cas A. The IRAC 8 $$\mu$$ m image including Ar ejecta is distributed in a shell-like morphology which is coincident with dust features, suggesting that dust has formed in the ejecta. We create a cold dust map that shows excess emission in the northwestern shell. We fit the spectral energy distribution of the SNR using the continuous distributions of ellipsoidal grain model of pre-solar grain SiO2 that reproduces the 21 and 9  $$\mu$$ m dust features and discuss grains of silicon carbide and polycyclic aromatic hydrocarbon that may be responsible for the 10–13  $$\mu$$ m dust features. To reproduce the long-wavelength continuum, we explore models consisting of different grains including Mg2SiO4, MgSiO3, Al2O3, FeS, carbon, and Fe3O4. We tested a model with a temperature-dependent silicate absorption coefficient. We detect cold dust (27–44 K) in the remnant, making this the fourth such SNR with freshly formed dust. The total dust mass in the SNR ranges from $$0.08\text{ to }0.9\, {\rm M}_{\odot }$$ depending on the grain composition, which is comparable to predicted masses from theoretical models. Our estimated dust masses are consistent with the idea that SNe are a significant source of dust in the early Universe. [ABSTRACT FROM AUTHOR]

We present Spitzer Multiband Imaging Photometer (MIPS) spectral energy distribution (SED) and Infrared Spectrograph (IRS) observations of 14 Galactic supernova remnants (SNRs) previously identified in the GLIMPSE survey. We find evidence for SNR/molecular cloud interaction through detection of [OI] emission, ionic lines, and emission from molecular hydrogen. Through blackbody fitting of the MIPS SEDs we find the large grains to be warm, 29-66 K. The dust emission is modeled using the DUSTEM code and a three-component dust model composed of populations of big grains (BGs), very small grains (VSGs), and polycyclic aromatic hydrocarbons. We find the dust to be moderately heated, typically by 30-100 times the interstellar radiation field. The source of the radiation is likely hydrogen recombination, where the excitation of hydrogen occurred in the shock front. The ratio of VSGs to BGs is found for most of the molecular interacting SNRs to be higher than that found in the plane of the Milky Way, typically by a factor of 2-3. We suggest that dust shattering is responsible for the relative overabundance of small grains, in agreement with the prediction from dust destruction models. However, two of the SNRs are best fitted with a very low abundance of carbon grains to silicate grains and with a very high radiation field. A likely reason for the low abundance of small carbon grains is sputtering. We find evidence for silicate emission at 20 fim in their SEDs, indicating that they are young SNRs based on the strong radiation field necessary to reproduce the observed SEDs. [ABSTRACT FROM AUTHOR]

I present observations of shock-processed PAHs and dust in supernova remnants (SNRs). Supernova shocks are one of the primary sites destroying, fragmenting and altering interstellar PAHs and dust. Studies of PAHs through supernova shocks had been limited because of confusion with PAHs in background emission. Spitzer observations with high sensitivity and resolution allow us to separate PAHs associated with the SNRs and unrelated, Galactic PAHs. In the young SNR N132D, PAH features are detected with a higher PAH ratio of 15-20/7.7 µm than those of other astronomical objects, and we suggest large PAHs have survived behind the shock. We present the spectra of additional 14 SNRs observed with Spitzer IRS and MIPS SED covering the range of 5-90 µm. Bright PAH features from 6.2 to 15-20 µm are detected from many of SNRs which emit molecular hydrogen lines, indicating that both large and small PAHs survive in low velocity shocks. We observe a strong correlation between PAH detection and carbonaceous small grains, while a few SNRs with dominant silicate dust lack PAH features. We characterize PAHs depending on the shock velocity, preshock density and temperature of hot gas, and discuss PAH and dust processing in shocks and implication of PAH and dust cycles in ISM. [ABSTRACT FROM AUTHOR]