We present a detailed analysis of AT 2020nov, a tidal disruption event (TDE) in the center of its host galaxy, located at a redshift of z = 0.083. AT 2020nov exhibits unique features, including double-peaked Balmer emission lines, a broad UV/optical flare, and a peak log luminosity in the extreme-ultraviolet (EUV) estimated at ∼ 45.6 6 − 0.33 + 0.10 erg s − 1 . A late-time X-ray flare was also observed, reaching an absorbed luminosity of 1.67 × 1043 erg s−1 approximately 300 days after the UV/optical peak. Multiwavelength coverage, spanning optical, UV, X-ray, and mid-infrared (MIR) bands, reveals a complex spectral energy distribution (SED) that includes MIR flaring indicative of dust echoes, suggesting a dust covering fraction consistent with typical TDEs. Spectral modeling indicates the presence of an extended, quiescent disk around the central supermassive black hole with a radius of ∼ 5.0 6 − 0.77 + 0.59 × 1 0 4 R g . The multicomponent SED model, which includes a significant EUV component, suggests that the primary emission from the TDE is reprocessed by this extended disk, producing the observed optical and MIR features. The lack of strong active galactic nuclei signatures in the host galaxy, combined with the quiescent disk structure, highlights AT 2020nov as a rare example of a TDE occurring in a galaxy with a dormant but extended preexisting accretion structure.

We present the discovery and early observations of the nearby Type II supernova (SN) 2024ggi in NGC 3621 at 6.64 +/- 0.3 Mpc. The SN was caught 5.8 (+1.9 -2.9) hours after its explosion by the ATLAS survey. Early-phase, high-cadence, and multi-band photometric follow-up was performed by the Kinder (Kilonova Finder) project, collecting over 1000 photometric data points within a week. The combined o- and r-band light curves show a rapid rise of 3.3 magnitudes in 13.7 hours, much faster than SN 2023ixf (another recent, nearby, and well-observed SN II). Between 13.8 and 18.8 hours after explosion SN 2024ggi became bluer, with u-g colour dropping from 0.53 to 0.15 mag. The rapid blueward evolution indicates a wind shock breakout (SBO) scenario. No hour-long brightening expected for the SBO from a bare stellar surface was detected during our observations. The classification spectrum, taken 17 hours after the SN explosion, shows flash features of high-ionization species such as Balmer lines, He I, C III, and N III. Detailed light curve modeling reveals critical insights into the properties of the circumstellar material (CSM). Our favoured model has an explosion energy of 2 x 10^51 erg, a mass-loss rate of 10^-3 solar_mass/yr (with an assumed 10 km/s wind), and a confined CSM radius of 6 x 10^14 cm. The corresponding CSM mass is 0.4 solar_mass. Comparisons with SN 2023ixf highlight that SN 2024ggi has a smaller CSM density, resulting in a faster rise and fainter UV flux. The extensive dataset and the involvement of citizen astronomers underscore that a collaborative network is essential for SBO searches, leading to more precise and comprehensive SN characterizations.

We present a new photometric pipeline for the detection of pre-supernova (pre-SN) emission in the Young Supernova Experiment (YSE) sky survey. The method described is applied to SN 2020tlf, a type II SN (SN II) with precursor emission in the last 100 days before first light. We re-analyze the YSE griz-band light curves of SN 2020tlf and provide revised pre-explosion photometry that includes a robust list of confident detection and limiting magnitudes. Compared to the results of Jacobson-Galan et al. 2022a, this new analysis yields fewer total r/i/z-band pre-SN detections at phases > -100 days. Furthermore, we discourage the use of the blackbody modeling of the pre-explosion spectral energy distribution, the pre-SN bolometric light curve and the blackbody model parameters presented in Jacobson-Galan et al. 2022a. Nevertheless, binned photometry of SN 2020tlf confirms a consistent progenitor luminosity of 10^40 erg s^-1 before explosion.

We present the class of extreme nuclear transients (ENTs), including the most energetic single transient yet found, Gaia18cdj. Each ENT is coincident with its host-galaxy nucleus and exhibits a smooth (<10% excess variability), luminous (2 × 1045 to 7 × 1045 erg per second), and long-lived (>150 days) flare. ENTs are extremely rare (≥1 × 10-3 cubic gigaparsec per year) compared to any other known class of transients. They are at least twice as energetic (0.5 × 1053 to 2.5 × 1053 erg) as any other known transient, ruling out supernova origins. Instead, the high peak luminosities, long flare timescales, and immense radiated energies of the ENTs are most consistent with the tidal disruption of high-mass ( [Formula: see text] ) stars by massive ( [Formula: see text] ) supermassive black holes (SMBHs). ENTs will be visible to high redshifts (z ~ 4 to 6) in upcoming surveys, providing an avenue to study the high-mass end of the SMBH mass distribution, complementing recent studies of actively accreting SMBHs at high redshifts with the James Webb Space Telescope.

We present optical photometric and spectroscopic observations of the peculiar Type Ia supernovae (SNe Ia) ASASSN-20jq/SN 2020qxp. It is a low-luminosity object, with a peak absolute magnitude of M-B = -17.1 +/- 0.5 mag, while its post-peak light-curve decline rate of Delta m(15)(B) = 1.35 +/- 0.09 mag and color-stretch parameter of s(BV) & gap; 0.82 is similar to that of normal luminosity SNe Ia. That makes it a prevalent outlier in both the SN Ia luminosity-width and the luminosity-color-stretch relations. The analysis of the early light curves indicates a possible "bump" during the first approximate to 1.4 days of explosion. ASASSN-20jq synthesized a low radioactive Ni-56 mass of 0.09 +/- 0.01 M-circle dot. The near-maximum light spectra of the supernova show strong Si II absorption lines, indicating a cooler photosphere than normal SNe Ia; however, it lacks Ti II absorption lines. Additionally, it shows unusually strong absorption features of O I lambda 7773 and the Ca II near-infrared triplet. The nebular spectra of ASASSN-20jq show a remarkably strong but narrow forbidden [Ca II] lambda lambda 7291, 7324 doublet emission that has not been seen in SNe Ia except for a handful of Type Iax events. There is also a marginal detection of the [O I] lambda lambda 6300, 6364 doublet emission in nebular spectra, which is extremely rare. Both the [Ca II] and [O I] lines are redshifted by roughly 2000 km s(-1). ASASSN-20jq also exhibits a strong [Fe II] lambda 7155 emission line with a tilted-top line profile, which is identical to the [Fe II] lambda 16433 line profile. The asymmetric [Fe II] line profiles, along with the redshifted [Ca II] and emission lines, suggest a high central density white dwarf progenitor that underwent an off-center delayed-detonation explosion mechanism, synthesizing roughly equal amounts of Ni-56 during the deflagration and detonation burning phases. The equal production of Ni-56 in both burning phases distinguishes ASASSN-20jq from normal bright and subluminous SNe Ia. Assuming this scenario, we simultaneously modeled the optical and near-infrared nebular spectra, achieving a good agreement with the observations. The light curve and spectroscopic features of ASASSN-20jq do not align with any single sub-class of SNe Ia. However, the significant deviation from the luminosity versus light-curve shape relations (along with several light-curve and spectroscopic features) exhibits similarities to some 2002es-like objects. Therefore, we have identified ASASSN-20jq as an extreme candidate within the broad and heterogeneous parameter space of 2002es-like SNe Ia.

Based on the rate of change of its orbital period, PSR J2043+1711 has a substantial peculiar acceleration of 3.5 ± 0.8 mm s ^–1 yr ^–1 , which deviates from the acceleration predicted by equilibrium Milky Way (MW) models at a 4 σ level. The magnitude of the peculiar acceleration is too large to be explained by disequilibrium effects of the MW interacting with orbiting dwarf galaxies (∼1 mm s ^–1 yr ^–1 ), and too small to be caused by period variations due to the pulsar being a redback. We identify and examine two plausible causes for the anomalous acceleration: a stellar flyby, and a long-period orbital companion. We identify a main-sequence star in Gaia DR3 and Pan-STARRS DR2 with the correct mass, distance, and on-sky position to potentially explain the observed peculiar acceleration. However, the star and the pulsar system have substantially different proper motions, indicating that they are not gravitationally bound. However, it is possible that this is an unrelated star that just happens to be located near J2043+1711 along our line of sight (chance probability of 1.6%). Therefore, we also constrain possible orbital parameters for a circumbinary companion in a hierarchical triple system with J2043+1711; the changes in the spindown rate of the pulsar are consistent with an outer object that has an orbital period of 60 kyr, a companion mass of 0.3 M _⊙ (indicative of a white dwarf or low-mass star), and a semimajor axis of 1900 au. Continued timing and/or future faint optical observations of J2043+1711 may eventually allow us to differentiate between these scenarios.

We present extensive observations of the Type II supernova (SN II) SN 2023ufx, which is likely the most metal-poor SN II observed to date. It exploded in the outskirts of a low-metallicity (Z host similar to 0.1 Z circle dot) dwarf (M g = -13.39 +/- 0.16 mag, r proj similar to 1 kpc) galaxy. The explosion is luminous, peaking at M g approximate to -18.5 mag, and shows rapid evolution. The r-band (pseudobolometric) light curve has a shock-cooling phase lasting 20 (17) days followed by a 19 (23) day plateau. The entire optically thick phase lasts only approximate to 55 days following explosion, indicating that the red supergiant progenitor had a thinned H envelope prior to explosion. The early spectra obtained during the shock-cooling phase show no evidence for narrow emission features and limit the preexplosion mass-loss rate to M less than or similar to 10-3 M circle dot yr-1. The photospheric-phase spectra are devoid of prominent metal absorption features, indicating a progenitor metallicity of less than or similar to 0.1 Z circle dot. The seminebular (similar to 60-130 days) spectra reveal weak Fe ii, but other metal species typically observed at these phases (Ti ii, Sc ii, and Ba ii) are conspicuously absent. The late-phase optical and near-infrared spectra also reveal broad (approximate to 104 km s-1) double-peaked H alpha, P beta, and P gamma emission profiles suggestive of a fast outflow launched during the explosion. Outflows are typically attributed to rapidly rotating progenitors, which also prefer metal-poor environments. This is only the second SN II with less than or similar to 0.1 Z circle dot and both exhibit peculiar evolution, suggesting a sizable fraction of metal-poor SNe II have distinct properties compared to nearby metal-enriched SNe II. These observations lay the groundwork for modeling the metal-poor SNe II expected in the early Universe.

We present high-cadence ultraviolet through near-infrared observations of the Type Ia supernova (SN Ia) 2023bee in NGC~2708 ($D = 32 \pm 3$ Mpc), finding excess flux in the first days after explosion relative to the expected power-law rise from an expanding fireball. This deviation from typical behavior for SNe Ia is particularly obvious in our 10-minute cadence $TESS$ light curve and $Swift$ UV data. Compared to a few other normal SNe Ia with detected early excess flux, the excess flux in SN 2023bee is redder in the UV and less luminous. We present optical spectra of SN 2023bee, including two spectra during the period where the flux excess is dominant. At this time, the spectra are similar to those of other SNe Ia but with weaker Si II, C II and Ca II absorption lines, perhaps because the excess flux creates a stronger continuum. We compare the data to several theoretical models that have been proposed to explain the early flux excess in SNe Ia. Interaction with either a nearby companion star or close-in circumstellar material is expected to produce a faster evolution than seen in the data. Radioactive material in the outer layers of the ejecta, either from a double detonation explosion or simply an explosion with a $^{56}$Ni clump near the surface, can not fully reproduce the evolution either, likely due to the sensitivity of early UV observable to the treatment of the outer part of ejecta in simulation. We conclude that no current model can adequately explain the full set of observations. We find that a relatively large fraction of nearby, bright SNe Ia with high-cadence observations have some amount of excess flux within a few days of explosion. Considering potential asymmetric emission, the physical cause of this excess flux may be ubiquitous in normal SNe Ia.

We present observations of ASASSN-22ci (AT2022dbl), a nearby tidal disruption event (TDE) discovered by the All-Sky Automated Survey for Supernovae (ASAS-SN) at a distance of d_L ≃ 125 Mpc. Roughly two years after the initial ASAS-SN discovery, a second flare was detected coincident with ASASSN-22ci. UV/optical photometry and optical spectroscopy indicate that both flares are likely powered by TDEs. The striking similarity in flare properties suggests that these flares result from subsequent disruptions of the same star. Each flare rises on a timescale of ∼30 days, has a temperature of ≈30,000 K, a peak bolometric luminosity of L_UV/Opt = 10^43.6 - 43.9 erg s^-1, and exhibits a blue optical spectrum with broad H, He, and N lines. No X-ray emission is detected during either flare, but X-ray emission with an unabsorbed luminosity of L_X = 3×10^41 erg s^-1 and kT = 0.042 eV is observed between the flares. Pre-discovery survey observations rule out the existence of earlier flares within the past ≈6000 days, indicating that the discovery of ASASSN-22ci likely coincides with the first flare. If the observed flare separation of 720 ± 4.7 days is the orbital period, the next flare of ASASSN-22ci should occur near MJD 61075 (2026 February 04). Finally, we find that the existing sample of repeating TDE candidates is consistent with Hills capture of a star initially in a binary with a total mass between ∼1 - 4 M_⊙ and a separation of ∼0.01 - 0.1 AU.

We describe a citizen science asteroid detection system developed by the International Astronomical Search Collaboration (IASC) and the Institute for Astronomy at the University of Hawaii, utilizing data from the PanSTARRS telescopes. The goals of this project are to (i) educate and engage citizen scientists (mostly high school students) in science and astronomy, (ii) search for new asteroids to extend the limiting magnitudes of existing asteroid surveys, and (iii) find missed Near -Earth Objects (NEOs-objects with perihelia q < 1.3 au) to support planetary defense efforts. Over the past 15 yr, 50,000 citizen scientists from 96 countries around the world have detected similar to 12,000 main -belt asteroids and similar to 5 NEOs. Citizen scientists use the software Astrometrica during scheduled campaigns to search for and measure asteroid astrometry and photometry, and submit the data to IASC for vetting. Candidate detections not already submitted by Pan-STARRS are then submitted to the Minor Planet Center, and are typically similar to 0.30 +/- 0.07 mag fainter.

The nearby type II supernova, SN 2023ixf in M101 exhibits signatures of early time interaction with circumstellar material in the first week postexplosion. This material may be the consequence of prior mass loss suffered by the progenitor, which possibly manifested in the form of a detectable presupernova outburst. We present an analysis of long-baseline preexplosion photometric data in the g, w, r, i, z, and y filters from Pan-STARRS as part of the Young Supernova Experiment, spanning similar to 5000 days. We find no significant detections in the Pan-STARRS preexplosion light curves. We train a multilayer perceptron neural network to classify presupernova outbursts. We find no evidence of eruptive presupernova activity to a limiting absolute magnitude of -7 mag. The limiting magnitudes from the full set of gwrizy (average absolute magnitude approximate to -8 mag) data are consistent with previous preexplosion studies. We use deep photometry from the literature to constrain the progenitor of SN 2023ixf, finding that these data are consistent with a dusty red supergiant progenitor with luminosity log L / L circle dot approximate to 5.12 and temperature approximate to 3950 K, corresponding to a mass of 14-20 M circle dot.

We introduce the Hawai'i Supernova Flows project and present summary statistics of the first 1217 astronomical transients observed, 668 of which are spectroscopically classified Type Ia Supernovae (SNe Ia). Our project is designed to obtain systematics-limited distances to SNe Ia while consuming minimal dedicated observational resources. To date, we have performed almost 5000 near-infrared (NIR) observations of astronomical transients and have obtained spectra for over 200 host galaxies lacking published spectroscopic redshifts. In this survey paper, we describe the methodology used to select targets, collect/reduce data, calculate distances, and perform quality cuts. We compare our methods to those used in similar studies, finding general agreement or mild improvement. Our summary statistics include various parametrizations of dispersion in the Hubble diagrams produced using fits to several commonly used SN Ia models. We find the lowest dispersions using the SNooPy package's EBV_model2, with a root mean square deviation of 0.165 mag and a normalized median absolute deviation of 0.123 mag. The full utility of the Hawai'i Supernova Flows data set far exceeds the analyses presented in this paper. Our photometry will provide a valuable test bed for models of SN Ia incorporating NIR data. Differential cosmological studies comparing optical samples and combined optical and NIR samples will have increased leverage for constraining chromatic effects like dust extinction. We invite the community to explore our data by making the light curves, fits, and host galaxy redshifts publicly accessible.

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 C i 1.0693 μ m feature that persists until 5 days post-maximum. We also detect C ii λ 6580 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.

We present Young Supernova Experiment grizy photometry of SN 2021hpr, the third Type Ia supernova sibling to explode in the Cepheid calibrator galaxy, NGC 3147. Siblings are useful for improving SN-host distance estimates and investigating their contributions toward the SN Ia intrinsic scatter (post-standardization residual scatter in distance estimates). We thus develop a principled Bayesian framework for analyzing SN Ia siblings. At its core is the cosmology-independent relative intrinsic scatter parameter, σ Rel : the dispersion of siblings distance estimates relative to one another within a galaxy. It quantifies the contribution toward the total intrinsic scatter, σ 0 , from within-galaxy variations about the siblings’ common properties. It also affects the combined distance uncertainty. We present analytic formulae for computing a σ Rel posterior from individual siblings distances (estimated using any SN model). Applying a newly trained BayeSN model, we fit the light curves of each sibling in NGC 3147 individually, to yield consistent distance estimates. However, the wide σ Rel posterior means σ Rel ≈ σ 0 is not ruled out. We thus combine the distances by marginalizing over σ Rel with an informative prior: σ Rel ∼ U (0, σ 0 ). Simultaneously fitting the trio’s light curves improves constraints on distance and each sibling’s individual dust parameters, compared to individual fits. Higher correlation also tightens dust parameter constraints. Therefore, σ Rel marginalization yields robust estimates of siblings distances for cosmology, as well as dust parameters for sibling–host correlation studies. Incorporating NGC 3147's Cepheid distance yields H 0 = 78.4 ± 6.5 km s −1 Mpc −1 . Our work motivates analyses of homogeneous siblings samples, to constrain σ Rel and its SN-model dependence.

We present photometric and spectroscopic observations and analysis of SN 2021bxu (ATLAS21dov), a low-luminosity, fast-evolving Type IIb supernova (SN). SN 2021bxu is unique, showing a large initial decline in brightness followed by a short plateau phase. With $M_r = -15.93 \pm 0.16\, \mathrm{mag}$ during the plateau, it is at the lower end of the luminosity distribution of stripped-envelope supernovae (SE-SNe) and shows a distinct $\sim$10 day plateau not caused by H- or He-recombination. SN 2021bxu shows line velocities which are at least $\sim1500\,\mathrm{km\,s^{-1}}$ slower than typical SE-SNe. It is photometrically and spectroscopically similar to Type IIb SNe during the photospheric phases of evolution, with similarities to Ca-rich IIb SNe. We find that the bolometric light curve is best described by a composite model of shock interaction between the ejecta and an envelope of extended material, combined with a typical SN IIb powered by the radioactive decay of $^{56}$Ni. The best-fit parameters for SN 2021bxu include a $^{56}$Ni mass of $M_{\mathrm{Ni}} = 0.029^{+0.004}_{-0.005}\,\mathrm{M_{\odot}}$, an ejecta mass of $M_{\mathrm{ej}} = 0.61^{+0.06}_{-0.05}\,\mathrm{M_{\odot}}$, and an ejecta kinetic energy of $K_{\mathrm{ej}} = 8.8^{+1.1}_{-1.0} \times 10^{49}\, \mathrm{erg}$. From the fits to the properties of the extended material of Ca-rich IIb SNe we find a trend of decreasing envelope radius with increasing envelope mass. SN 2021bxu has $M_{\mathrm{Ni}}$ on the low end compared to SE-SNe and Ca-rich SNe in the literature, demonstrating that SN 2021bxu-like events are rare explosions in extreme areas of parameter space. The progenitor of SN 2021bxu is likely a low mass He star with an extended envelope.

We previously reported a rare class of variable star light curves isolated from a sample of 4.7 million candidate variables from the ATLAS survey. Dubbed “UCBH” light curves, they have broad minima and narrow, symmetrical maxima, with typical periods of 1–10 days and amplitudes of 0.05–0.20 mag. They maintain constant amplitude, shape, and phase coherence over multiple years but do not match any known class of pulsating variables. A localized bright spot near the equator of a rotating star will produce a UCBH-type light curve for most viewing geometries. Most stars that exhibit rotational variability caused primarily by a single bright feature should therefore appear as UCBH stars, although a rotating bright spot is not the only thing that could produce a UCBH-type light curve. We have spectroscopically investigated 14 UCBH stars and found 10 of them to be Ap/Bp stars: A-type or B-type stars with greatly enhanced photospheric abundances of specific heavy elements. Rotationally variable Ap/Bp stars are referred to as α 2 CVn variables. Most ATLAS UCBH stars are therefore α 2 CVn stars, although only a minority of α 2 CVn stars in the literature have UCBH light curves. The fact that α 2 CVn stars dominate the UCBH class suggests that lone bright spots with sufficient size and contrast develop more readily on Ap/Bp stars than on any other type. The α 2 CVn UCBH stars may be characterized by a specific magnetic field topology, making them intriguing targets for future Zeeman–Doppler imaging.

ASASSN-14ko is a recently discovered periodically flaring transient at the center of the active galactic nucleus (AGN) ESO 253−G003 with a slowly decreasing period. Here, we show that the flares originate from the northern, brighter nucleus in this dual-AGN, post-merger system. The light curves for the two flares that occurred in 2020 May and September are nearly identical over all wavelengths. For both events, Swift observations showed that the UV and optical wavelengths brightened in unison. The effective temperature of the UV/optical emission rises and falls with the increase and subsequent decline in the luminosity. The X-ray flux, by contrast, first rapidly drops over ∼2.6 days, rises for ∼5.8 days, drops again over ∼4.3 days, and then recovers. The X-ray spectral evolution of the two flares differ, however. During the 2020 May peak the spectrum softened with increases in the X-ray luminosity, while we observed the reverse for the 2020 September peak. We found a small change in the period derivative, which seems to indicate that the system does not have a static period derivative and there is some stochasticity in its evolution.

The Pan-STARRS telescopes on Haleakala, Maui, search the sky every night for objects that pass close to Earth. The Pan-STARRS1 telescope has been in operation for over 10 years. The Pan-STARRS2 telescope is now delivering similar performance, and together these telescopes can survey most of the available sky twice during each lunation. Pan-STARRS2 experienced some early technical issues. These included secondary mirror mount problems, and use of a silver coating on the secondary mirror, which degraded rapidly after Kilauea erupted on the island of Hawaii. The secondary mirror was recoated with protected aluminum, and the mirror mount problems solved. Pan-STARRS2 now delivers slightly better throughput compared to Pan-STARRS1, due to its newer mirror coating. Image quality is currently similar on each of the two telescopes, and is mostly limited by local atmospheric conditions (“seeing”). Prior to 2021, the reporting latency of Pan-STARRS did not allow for immediate follow up of new discoveries. But this latency has been reduced and Pan-STARRS now attempts same-night self-recovery of many of its newly discovered Near-Earth Objects. This extends the orbital arc from approximately 1 hour to 3–4 hours. Because of Earth rotation, the motion of the observer produces parallax that helps to constrain the distance and size of the Near-Earth Object, thereby reducing the future positional uncertainty, and aiding in recovery. One of the most important discoveries of Pan-STARRS to date is the interstellar object 'Oumuamua. It is likely that Pan-STARRS detected other interstellar objects in the past, but without rapid follow-up they were not recovered. The same-night follow up should aid in the discovery of interstellar objects in the future. Pan-STARRS produces excellent astrometry, and often sees curvature in the path of nearby Near-Earth Objects. This is caused by Earth's rotation, and is an indication that an object is very nearby. Pan-STARRS has not yet discovered an impacting asteroid before impact. However, the ability to see curvature, to-gether with the new capability for same-night follow up, and the improved sky coverage coming from two telescopes, makes Pan-STARRS a powerful tool for discovering impacting asteroids.

We present observations of ASASSN-20hx, a nearby ambiguous nuclear transient (ANT) discovered in NGC 6297 by the All-Sky Automated Survey for Supernovae (ASAS-SN). We observed ASASSN-20hx from $-$30 to 275 days relative to peak UV/optical emission using high-cadence, multi-wavelength spectroscopy and photometry. From Transiting Exoplanet Survey Satellite (TESS) data, we determine that the ANT began to brighten on 2020 June 22.8 with a linear rise in flux for at least the first week. ASASSN-20hx peaked in the UV/optical 30 days later on 2020 July 22.8 (MJD = 59052.8) at a bolometric luminosity of $L = (3.15 \pm 0.04) \times 10^{43}$ erg s$^{-1}$. The subsequent decline is slower than any TDE observed to date and consistent with many other ANTs. Compared to an archival X-ray detection, the X-ray luminosity of ASASSN-20hx increased by an order of magnitude to $L_{x} \sim 1.5 \times 10^{42}$ erg s$^{-1}$ and then slowly declined over time. The X-ray emission is well-fit by a power law with a photon index of $\Gamma \sim 2.3 - 2.6$. Both the optical and near infrared spectra of ASASSN-20hx lack emission lines, unusual for any known class of nuclear transient. While ASASSN-20hx has some characteristics seen in both tidal disruption events (TDEs) and active galactic nuclei (AGNs), it cannot be definitively classified with current data.

We present a search for disturbed, candidate ram pressure stripping galaxies across more than 50 spectroscopically selected SDSS groups and clusters. 48 ram pressure candidates are visually identified in these systems using high-quality UNIONS imaging from the Canada-France-Hawaii Telescope, covering similar to 6200 deg(2) and similar to 2800 deg(2) in the u- and r-bands, respectively. Ram pressure candidates are found in groups and clusters spanning a wide range in halo mass and include similar to 30 ram pressure candidates in the group regime (M-h < 10(14)). The observed frequency of ram pressure candidates shows substantial scatter with group/cluster mass, but on average is larger in clusters (M-h >= 10(14)M(circle dot)) than groups (M-h < 10(14) M-circle dot) by a factor of similar to 2. We find that ram pressure candidates are most commonly low-mass galaxies and have enhanced star formation rates relative to star-forming field galaxies. The enhancement in star formation is largely independent of galaxy mass and strongest for galaxies in clusters. As a result of the large survey footprint and excellent image quality from UNIONS, we are able to identify disturbed galaxies, potentially affected by ram pressure stripping, across a wide range of host environment.