Schedule

The conference will be held all day from May 20 to 22, 2025 at the Phillips auditorium of the Center for Astrophysics | Harvard & Smithsonian in Cambridge, MA.

Posters and talks are available on this Google Drive.

Tuesday - May 20th

Matt Nicholl

Queen's University Belfast

Optical properties of Type I superluminous supernovae

I will review the optical properties of superluminous supernovae, giving a brief overview of how these objects are defined and differentiated from other supernovae in their optical light curves and spectra, and what these basic properties imply for their temperatures and powering mechanisms. I will discuss the diversity within the class, the complex behavior of their light curves, and the constraints on progenitors from late-time optical observations. Comparing these properties to different models, I will discuss what we think we know about superluminous supernovae, and where the big questions remain.

Manos Chatzopoulos

Louisiana State University

Simulating Transients Powered by Circumstellar Interaction Using the Open-Source SuperLite Code

We perform detailed spectroscopic modeling to study the interaction between ejecta and circumstellar material (CSM) in hydrogen-rich and hydrogen-poor superluminous supernovae (SLSNe). By systematically varying CSM properties—density, composition, and geometry—and using advanced radiative transfer simulations with the open-source SuperLite code, we identify key spectroscopic indicators of CSM characteristics. In hydrogen-rich SLSNe-II, we find pronounced hydrogen emission lines correlating with dense, extended CSM, indicative of massive, eruptive mass-loss histories. For hydrogen-poor SLSNe, early-time spectra are mostly featureless, with weak hydrogen lines appearing briefly due to rapid ionization of trace hydrogen in the CSM. We analyze spectral features, particularly Hα and Hβ, using statistical methods to show how variations in progenitor and CSM properties drive distinct spectroscopic evolution. These temporal changes offer critical insights into explosion physics and pre-explosion mass loss, linking spectroscopic observations to progenitor and CSM properties.

Brian Metzger

Columbia University/Flatiron CCA

Engines of Superluminous Supernovae

I will review models of superluminous supernovae, focusing on scenarios involving a central engine. I will describe the motivations for and ingredients of a self-consistent "magnetar" model. This model predicts how spin-down energy released in the electron-positron wind of the magnetar is converted into high energy radiation, which ultimately thermalizes with the ejecta with some efficiency. This has implications for late-time heating of the ejecta, and the potential "leakage" of gamma-ray radiation. I will also discuss the potential escape of relativistic jets from the expanding supernova ejecta, and how "continuous" shock break-out of such a jet could power early "bumps" seen in some Type I SLSNe. Time permitting, I will show how central energy input (e.g. from a magnetar or CSM shock interaction) can extend the plateau duration and luminosity of hydrogen-rich SNe, including SLSNe.

Kiran Eiden

University of California, Berkeley

Numerical Simulations of Superluminous Transients Powered by Central Engines

A subpopulation of superluminous supernovae are suspected to be powered by central engines, either in the form of a rapidly-rotating magnetar or an accreting black hole or neutron star. This subpopulation is heterogeneous in its photometric and spectral features, but there remains uncertainty regarding the observational signatures of engine-powered supernovae and how the range of possible engines and engine properties could map onto this diverse supernova landscape. In this talk, I will present the results of multidimensional hydrodynamics simulations of supernovae with a central power source. I will also share synthetic light curves and spectra obtained by post-processing these simulations with a Monte Carlo radiation transport code. I will discuss how these energy sources impact the dynamics and observational signatures of the explosions that harbor them, and how the variety of possible parameters may account for the diversity in the supernovae central engines have been brought forth to explain.

Anamaria Gkini

Stockholm University / OKC

Chasing eruptive mass loss prior to superluminous supernovae

The fate of stars and the type of the resulting supernova (SN) are closely linked to their final years before core collapse. During the late stages of stellar evolution, stars can lose a significant amount of their initial mass through eruptive mass loss, leading to the formation of circumstellar material (CSM) around the SN. The existence of CSM can be revealed in the spectra of SNe in the form of resonance lines in the near-ultraviolet (NUV). In this talk, I will focus on an exceptionally bright class of SNe known as superluminous supernovae (SLSNe). In particular, I will present a NUV spectroscopic sample of SLSNe to search for evidence of CSM shells, ejected shortly before the explosion. First, I will discuss two SLSNe from the sample where CSM shells were detected, inferring their properties and the timing of their ejection. Then, I will expand the discussion to the entire sample, focusing on the modeling of the spectral region where CSM-related lines are expected. This will aid in investigating the occurrence of fast-moving CSM around SLSNe and determining the distribution of the CSM properties. Finally, I will constrain mass-loss rates in progenitors that explode as SLSNe and discuss potential mass-loss mechanisms. The discovery of these objects offers valuable insight into the late stages of stellar evolution and enhances our understanding of SLSN progenitors.

Harsh Kumar

CfA

A Near-IR Search for Helium in the Superluminous Supernova SN2024ahr

Modern wide-field optical time-domain surveys have enabled the discovery of a rare class ( (rate ~0.3% of stripped-envelope SNe) of transients dubbed "hydrogen poor superluminous supernovae" (SLSNe-I), which can exceed the luminosity of normal stripped-envelope core-collapse Supernovae (Type Ib and Ic SNe) by two orders of magnitude. Due to their low rate, these events have not been studied in detail, especially at near-IR wavelengths. Here, we present a detailed study of SN2024ahr, a hydrogen-poor superluminous supernova (SLSN-I) at a redshift of z=0.0861 and has a peak absolute magnitude of M_g ~ M_r ~ -21 mag. Due to its relatively low redshift, we obtained a high signal-to-noise ratio near-IR spectrum of about 43 rest-frame days post-peak to search for the presence of helium. We detect Ic SNe like broad features of Mg I, CO II and Mg II, but with higher velocities. We do not detect any significant feature at the location of the He I 2.058 um feature (a key unblended feature representing helium presence/absence), and place a conservative limit of < 0.05 M_sun on the mass of helium in the outer ejecta, implying that SN2024ahr is stripped of the majority of its helium layer before the explosion. Examining the sample of SLSNe-I with NIR spectroscopy, we find that, unlike SN2024ahr, the present sample consists of peculiar events, highlighting the need for a large sample of prototypical SLSNe-I with NIR spectroscopy to constrain the fraction of progenitors with (Ib-like) and without (Ic-like) helium at the time of the explosion, and hence the evolutionary path leading to the rare outcome of SLSNe-I.

Raffaella Margutti

UC Berkeley

SLSNe in the X-rays and radio are not superluminous

In this talk I will provide an overview of the results from systematic X-ray and radio campaigns of SLSNe.

Wednesday - May 21st

Ragnhild Lunnan

Stockholm University

Observational properties of H-rich superluminous supernovae

Like other supernovae, superluminous supernovae separate into a hydrogen-rich and a hydrogen-poor subclass spectroscopically. With a few exceptions, however, the hydrogen-rich subclass has received relatively less attention from the community than their hydrogen-poor counterparts. In this talk, I will review what we know about the observational properties of H-rich superluminous supernovae, drawing largely on the samples compiled by the Zwicky Transient Facility as well as other surveys. I will discuss challenges in detecting and classifying H-rich superluminous supernovae, as well as population properties and potential sub-classes, and how these may be related to proposed progenitor scenarios and powering mechanisms.

Daichi Hiramatsu

CfA

Uniform Light-Curve Characterization of Type IIn Supernovae

I present the largest uniform study to date of Type IIn supernovae (SNe IIn), focusing in this talk on the observed properties of their multi-band optical light curves. SNe IIn span broad ranges in peak luminosity (~1e42–1e44 erg/s) and timescales (~20–300 days above 50% of peak luminosity); however, our key finding is that the sample divides into two clear groups in the luminosity-timescale phase-space around the median peak luminosity (~1e43 erg/s): faint-fast (~40 days) and luminous-slow (~100 days) groups. This leads to a strong bimodality in the radiated energy distribution, peaking at ~1e49 and 2e50 erg. Therefore, SNe IIn exhibit at least two dominant groupings, which are likely reflective of different progenitor and/or circumstellar medium formation pathways. No obvious transition in SN IIn properties is found at the arbitrary cut-off (~-20 mag) used for the designation "Type II Superluminous Supernovae”. The absence of SNe IIn with timescales of <14 days defines the region occupied by fast transients with evidence for interaction with hydrogen-poor circumstellar medium.

Wasundara Athukoralalage

CfA

Exploring Double-Peaked Long Duration Type IIn Supernovae

Type IIn supernovae (SNe IIn) are hydrogen-rich stellar explosions classified by the presence of “narrow'' Balmer-series emission lines in their spectra, powered by the shock interaction between the ejecta and a dense circumstellar material (CSM) shed by the progenitor star prior to explosion. As a result, they exhibit a broad range of luminosities and timescales that depend on the diverse combination of CSM and explosion properties indicative of a range of progenitor types and mass loss mechanisms. SNe IIn with multi-peaked light curves suggest complex CSM structures and eruptive mass loss. Therefore, studying such events provides an opportunity to understand mass-loss activity of complex progenitor systems and their environments. We present a unique sample of five SN IIn with double-peaked long duration light curves and use detailed optical photometry and spectroscopy to comprehensively characterize their complex mass loss history. These spectra are dominated by Balmer lines with a complex morphology, including narrow emission and P Cygni components. Coupling the spectra, luminosity, and velocity evolution, we can analytically model mass-loss histories. Observations of this rare subtype of SNe IIn and their host galaxies with space-based telescopes will be key for independent constraints on the CSM density and detailed studies of their birth environments.

Conor Ransome

CfA

Unveling the Diversity of Type IIn Supernovae

The enigmatic type IIn class of supernovae (SNIIn) claim a vast territory on the timescale-luminosity phase-space. Spanning from the sub--to-superluminous, these transients are characterised by persistent signatures of interaction with a pre-existing, dense, slow, and often massive circumstellar medium made up of mass lost from the progenitor by massive winds and/or non-terminal eruptions. This however, is where the inter-class similarities end as SNeIIn are highly heterogenous in terms of their observed photometric and spectroscopic features, some even turn out to be impostors! This heterogenieity in SN properties (also mirrored in their environments) suggests multiple progenitor routes, with confirmed progenitors being massive luminous blue variables, there is, however, evidence for much less massive progenitors. While these objects are somewhat rare, recent survey efforts have built up a samples of 100s of SNeIIn with good spectroscopic and photometric followup. This sample (built from Pan-STARRS, PTF, ZTF and YSE datasets along with literature data) allows us to explore for the first time, the broad range of properties that can be deduced from light curve modeling using MOSFiT. We probe the diverse landscape of SNeIIn to determine whether there may be distinct groups of SNeIIn or if there is a continuum in explosion parameters.

Danielle Frostig

CfA

An anomalous type I superluminous supernova

As we build larger samples of superluminous supernovae (SLSNe), we also uncover more anomalous events. In this talk, I present an unusual Type I SLSN, with an atypical light curve, spectroscopic features, and host environment. The standard magnetar model, often used to explain Type I SLSNe, does not easily fit this event, suggesting a different power source. I will present alternative models to fit this event and their implications for the broader diversity of SLSNe. Upcoming surveys, such as LSST, will likely uncover entire populations of similarly unusual transients, highlighting the need for flexible models and robust identification methods.

Takashi Moriya

National Astronomical Observatory of Japan

Modeling interaction-powered superluminous supernovae

The interaction between supernova ejecta and dense circumstellar matter has been considered to be a powering mechanism of some superluminous supernovae. I will discuss the basic idea of the circumstellar interaction. Especially I discuss the discrepancies between simple semi-analytic models and numerical models found in interaction-powered supernova modeling. I will also discuss the effects of multi-dimensional circumstellar matter and how the observed properties are affected by the asphericity. If time allows, I plan to discuss the precursor bumps observed in superluminous supernovae.

Brian Hsu

Steward Observatory, University of Arizona

An Extensive Hubble Space Telescope Study of the Offset and Host Light Distributions of Type I Superluminous Supernovae

We present an extensive Hubble Space Telescope (HST) rest-frame ultraviolet (UV) imaging study of the locations of Type I superluminous supernovae (SLSNe) within their host galaxies. The sample includes 65 SLSNe with detected host galaxies in the redshift range z=0.05-2. Using precise astrometric matching with SN images, we determine the distributions of the physical and host-normalized offsets relative to the host centers, as well as the fractional flux distribution relative to the underlying UV light distributions. We find that the host-normalized offsets of SLSNe roughly track an exponential disk profile, but exhibit an overabundance of sources with large offsets of 1.5-4 times their hosts' half-light radii. The SLSNe normalized offsets are systematically larger than those of long gamma-ray bursts (LGRBs), and even Type Ib/c and Type II SNe. Furthermore, we find from a Monte Carlo procedure that about (31-45)% of SLSNe occur in the dimmest regions of their host galaxies, with a median fractional flux value of 0.16, in stark contrast to LGRBs and Type Ib/c and Type II SNe. We do not detect any significant trends in the locations of SLSNe as a function of redshift, or as a function of explosion and magnetar engine parameters inferred from modeling of their optical light curves. The significant difference in SLSN locations compared to LGRBs (and normal core-collapse SNe) suggests that at least some of their progenitors follow a different evolutionary path. We speculate that SLSNe arise from massive runaway stars from disrupted binary systems, with velocities of ~100 km/s.

Anya Nugent

CfA

Investigating the Host Galaxy Properties of Core-Collapse Supernovae

We are quickly approaching an era of rapid transient discovery, with upcoming missions such as the Vera Rubin Observatory and NASA’s Roman expected to discover thousands of transients per night, including superluminous and core-collapse supernovae (SLSNe, CCSNe). The vast majority of these transients will only have scarce photometric coverage, leaving transient identification extremely challenging and progenitor inference even more so. Thus, before entering this era, we require comprehensive analyses of transients to uncover unique qualities that will be helpful in correctly identifying them when there are few photometric probes. Indeed, transient host galaxy stellar population properties (stellar mass, stellar population age, star formation rate, metallicity, etc.) may be crucial in distinguishing transient classes and understanding when they are misclassified from traditional machine-learning algorithms focused on transient emission alone. Here, I a new method to associate newly discovered transients to their host galaxies and determine the hosts stellar population properties with data from public imaging surveys. Through testing this method on several thousand transients and their hosts, I determine how useful host properties will be in distinguishing SLSNe from other types of CCSNe. I finally discuss how we can use these methods for progenitor studies on SLSNe.

Alex Gagliano

CfA/MIT

Bayesian Association of SLSN Host Galaxies

Superluminous supernovae are predominantly associated with highly star-forming dwarf galaxies, and recent studies have also reported systematically higher offsets for SLSNe-I than normal core-collapse supernovae. SLSNe will be discovered in abundance with the impending Vera C. Rubin Observatory, but the faint and offset nature of their host galaxies makes automated host identification challenging. In this talk, I present Prost, a bayesian host-galaxy association technique that will enable scalable host galaxy studies in the coming years. Given a galaxy catalog and a set of priors over galaxy properties, Prost calculates the posterior probability of each galaxy hosting a transient of interest in ~1s. We show the utility of Prost in rapidly consolidating the properties of SLSN hosts, compare our results to PATH (an alternative host association technique), and investigate the sensitivity of the associations on the chosen priors.

Thursday - May 22nd

Miika Pursiainen

University of Warwick, UK

A Type I superluminous supernova without an additional power source?

Superluminous supernovae (SLSNe), are a remarkable class of stellar explosions. They are bright enough to overshadow their host galaxies, but their light curves are typically inconsistent with the canonical Ni-56 decay chain, and other mechanisms, such as spin-down of a magnetar, have been considered. 

In this talk, I will present the analysis of an extensive optical dataset of a SN that is observationally similar to SLSNe-I but without evidence for an additional power source. It, for instance, exhibits a fast (~10d) and bright (-20mag) pre-peak which is nearly identical to those seen in SLSNe such as DES14X3taz. However, the precursor is not followed by a bright, slow “SLSN-like” main peak, and instead, the SN rises very marginally to only –19mag before starting a decline 20d post-explosion. The main light curve can also be modelled purely with Ni-56 decay, and photometry taken at +200-400d implies ~0.3 Solar masses of Ni-56 – significantly more than seen in normal Type Ic SNe. The event resembles SLSNe-I even spectroscopically: the spectra of the pre-peak reveal the characteristic OII “w” absorption over a blue continuum, while afterwards the spectra are reminiscent of SLSNe-I albeit much redder. Based on its observable properties, the SN appears to be an explosion of a progenitor star similar to those of at least some SLSNe-I, but the additional power source never turned-on. As such, the SN allows a unique opportunity to investigate the properties of a SLSN-I progenitor in detail without an uncertain powering mechanism affecting the analysis.

Trang Huynh

Louisiana State University

Rotational Dynamics in Pulsational Pair-Instability Supernovae: Implications for Mass-Loss and Transient Events

Pulsational pair-instability supernovae (PPISNe) are transient events occurring in progenitor stars with helium cores below ∼65 Msun, where rapid electron-positron pair production induces pressure loss, collapse, and pulsations that drive episodic mass loss. The number, strength, and duration of these pulses can lead to shell collisions that produce shock-powered transients, potentially explaining some of the most luminous events, such as super-luminous supernovae (SLSNe). Rapid progenitor rotation lowers the stellar mass threshold for PPISNe and influences the dynamics, energetics, and chemical composition of PPISN-driven pulses. In this study, we computed 1D evolutionary models of massive, rotating PPISN progenitor stars with ZAMS masses of 85–140 Msun and metallicities of Z=Zsun and Z=0.1*Zsun. Our analysis reveals strong correlations between PPISN ejected mass and kinetic energy as well as between ejected mass and peak ejected shell velocity. Additionally, moderate correlations indicate that higher initial PPISN progenitor mass leads to greater mass ejection and energy release, while negative correlations show that rapid rotation appears to reduce mass ejection and kinetic energy of the shells. Subsequent pulses lead to hydrogen-poor, carbon- and oxygen-enriched ejected shells, indicating the effect of rotationally-induced chemical mixing PPISN-driven episodic mass-loss with implications for their transients. We model the light curve and synthetic spectra that arise from the collision of two H-poor shells for one of our models using the radiation transport code SuperLite. We find that shock-heated H-poor PPISN shell collisions can lead to luminous H-poor transients that share similarities with SLSN-I.

Steve Schulze

Northwestern University

The Pair-instability Supernova Candidate 2018ibb

Pair-instability supernovae (PISNe) are predicted thermonuclear explosions of stars with zero-age-main-sequence masses between ~140 and ~260 Msun. Their massive ejecta and vast amounts of freshly nucleosynthesised radioactive nickel can create long-lived and luminous transients in the regime of superluminous supernovae. PISNe are not only very intriguing objects from the point of view of stellar evolution, but they also play a crucial role in fundamental physics. Therefore, confirming the existence of PISNe or narrowing the PISN parameter space through rejecting PISN candidates are critical tests for multiple fields in astrophysics. In this talk, I will present the properties of the best PISN candidate to date – SN 2018ibb. Using observations spanning 1100 days, I will show that SN 2018ibb complies with most tests of existing PISN models. However, some of its properties are in tension with PISN models. I will conclude the talk by proposing extensions to existing models.

Aysha Aamer

Queen's University Belfast

The Type I Superluminous Supernova Catalogue II: Spectroscopic Evolution in the Photospheric Phase, Velocity Measurements, and Constraints on Diversity

Hydrogen poor superluminous supernovae (SLSNe) are among the most energetic explosions in the universe, reaching luminosities up to 100 times greater than those of typical supernovae. Although the powering mechanisms of SLSNe remain a mystery, detailed spectral analysis holds the potential to reveal their progenitors and underlying energy sources. This talk will present the largest compilation of SLSN photospheric spectra to date, encompassing data from ePESSTO+, the FLEET search, and all published spectra up to December 2022. I present a catalogue of 234 objects and 974 spectra in total. I will explore the spectral evolution of these transients, showing that SLSNe initially exhibit hot (10,000–11,000 K) blue continua with weak spectral features. They then undergo a rapid transformation, cooling to 5,000–6,000 K within 40 days post-peak, leading to stronger P-Cygni features. There is also some evidence that many SLSNe might retain some helium at the time of their explosion. To investigate potential sub-populations, I will discuss the application of machine learning techniques, such as Principal Component Analysis, to identify structure within the dataset. While we find no evidence for statistically significant sub-populations, we do identify outliers with unusual spectral evolution and signatures of interaction. I will also examine Fe II λ5169 line velocities, which closely track the radius implied by blackbody fits, suggesting formation near the photosphere. This analysis also confirms a correlation between velocity and velocity gradient, consistent with a scenario in which all SLSNe undergo homologous expansion but with varying scale velocities. This behaviour aligns with expectations for an internal powering mechanism.

Rachid Ouyed

University of Calgary, Alberta, Canada

The Quark-Nova model for SLSNe

The Quark-Nova (QN), proposed as an energy and spallation source, is presented. A QN occurring days to months after a supernova (SN) could explain several intriguing features of Superluminous Supernovae (SLSNe), particularly double-peaked SLSNe. This model is applied to a range of candidate events, including SN 2023aew, SN 2022xxf, and SN 2020nwt.

Réka Könyves-Tóth

Konkoly Observatory, Hungary

New bolometric light curve modeling of 98 SLSNe-I suggests larger ejecta masses than previous studies

In this poster I present the bolometric light curve modeling of 98 hydrogen-poor superluminous supernovae (SLSNe-I) using three types of power inputs of the Minim code: the magnetar model and the constant density- and the steady wind scenarios of the circumstellar instaraction models. The quasi-bolometric fluxes of the SLSNe- were calculated from the ZTF g- and r-band data using the methodology of Chen et al. (2023a), while ejecta velocities were estimated from spectroscopy applying the method used in Könyves-Tóth et al. (2021). After the modeling it was found that 14 SLSNe-I favor the magnetar model, the light curve of 39 objects can be fitted better with the CSM model, while the luminosity of 45 supernovae can be explained equally well with both models. The magnetar modeling yielded a spin period and magnetic field (P and B) consistent with the literature, however, the ejected masses were found to be significantly larger than the estimates of previous studies using either multi-color light curve modeling with MOSFiT or bolometric light curve modeling. The mean ejecta mass value calculated from magnetar modeling was found to be 34.25 Mo ranging from 1.53 to 198.1 Mo, while the circumstellar interaction models resulted in even larger ejecta masses: a mean of 116.82 Mo was obtained from the constant density model, and 105.99 Mo from the steady wind scenario. The electron scattering opacity was assumed to be κ = 0.2 in this work, and in addition this value, the ejecta velocities, which play an important role in the ejecta mass calculations, were estimated to be globally larger compared to previous studies. These results suggest that SLSNe-I, exploding with either the magnetar or the CSM scenario, are indeed the explosions of the most massive stars.

Etienne Russeil

Stockholm University

Machine learning classification of superluminous supernovae candidates in big data surveys

Superluminous Supernovae (SLSNe) are rare and extremely bright stellar explosions for which the precise powering mechanism is not yet fully understood. Modern wide-field optical surveys, such as the Zwicky Transient Facility (ZTF), have allowed the automatic photometric detection of many SLSNe events, contributing greatly to the constraints on our models. The upcoming Vera C. Rubin Observatory will significantly increase the number of SLSNe candidates by probing our Universe more deeply. It is expected to detect 10 million variable sources per night, an order of magnitude more than ZTF.

In such big data surveys, efficiently identifying SLSNe among the vast number of transient alerts is very challenging and tailored pipelines should be constructed. Ideally, they should be fast enough to process large amounts of data, and interpretable enough to be trusted and used by the community. 

We address this challenge using a curated sample of spectroscopically confirmed SLSNe to develop a machine learning classification framework for ZTF data. At its core lies a feature extraction based on a multi-band fit of light curves, enabling the computation of physically-motivated features, such as rise and decay timescales or temperature evolution. In this talk, we present the details of the pipeline, and we explore different aspects of its classification, including distinguishing between subclasses of SLSNe, and the challenge of separating them from tidal disruption events. Finally, we will discuss potential adaptations for the Rubin Observatory.

Xinyue Sheng

Astrophysics Research Centre, Queen's University Belfast, UK

Attention-based Data Pre-processing and Upsampling for Enhancing SLSN-I Identification

NEEDLE is a classifier to identify early-stage SLSN-I and TDE using real-time ZTF alerts, with future applications to LSST. Between March 2024 and February 2025, NEEDLE has successfully predicted five SLSN-I and four TDEs at their early stages, with results published in AstroNotes. Given that SLSN-I and TDEs constitute only 0.02% of the accessible dataset, training the model on such highly imbalanced data is challenging. Additionally, SLSN-I host galaxies are often faint dwarfs, making it difficult for the CNN to focus on the target rather than nearby bright sources.

To address these issues, we enhance both contextual and photometric data utilization. For images, we apply Structural Similarity Index (SSIM) to reconstruct low-quality detections, mask nearby sources, and generate augmented samples with arbitrary rotations to emphasize targets and hosts. For light curves, we employ 2D Gaussian Processes to model correlations between the g and r bands, enabling high-cadence upsampling. We then simulate uncertainties and transform the data to the rest frame to generate new light curves.

By cross-matchiing these improved images and upsampled light curves, we increase the SLSN-I samples by over an order of magnitude, mitigating class imbalance and enhancing homogeneity. This approach significantly improves the robustness of SLSN-I identification

Jeff Cooke

Swinburne University

High redshift SLSNe: Observational insights into their identification, progenitors, and utility

Over the last two decades, we have discovered core-collapse supernovae (CCSNe) and superluminous supernovae (SLSNe) at z > 2 in ground-based surveys not specifically designed for such searches. We have identified more than 50 supernovae at z ~ 2-5 and confirmed more than 20 either with light curves and host galaxy redshifts, late-time emission lines (Type IIn supernovae), and/or spectroscopically near peak light. In addition, JWST has recently found a few events serendipitously in their small fields of view. With targeted ground-based surveys, NASA Roman and JSWT, and the ELTs, we have now entered the high redshift supernova era where large numbers of CCSNe and SLSNe will be found, and above z ~ 10. I will discuss what has been learned from the current detections, their insight into SLSN progenitors based on their host galaxies, and the utility of z > 2 supernovae, from conventional uses, such as measuring the high-redshift SLSN rates and high-mass-end of the stellar initial mass function, to less expected uses, such as their impact on cosmic reionisation from the events themselves and as probes of the escaping ionizong flux from their host galaxies, to their use as promising standardisable candles from z ~ 0 - 20. Finally, I will discuss the urgent need for a supernova UV classification system to help identify, classify, and do science with all z.> 4 supernovae detected in the future.

V. Ashley Villar

CfA

Data-driven methods to enable Rubin SLSN science

LSST is expected to discover ~>10k SLSNe-I and ~1000s of SLSNe-II annually, with many discovered in the high-z (z>1) universe. I will discuss recent developments in automated classification and rapid regression to enable large-scale population studies of these populations.