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VERSION:2.0
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BEGIN:VEVENT
SUMMARY:Lattice simulations of alpha-attractor inflation: numerical sensit
 ivity and model comparisons
DTSTART;VALUE=DATE-TIME:20261028T182600Z
DTEND;VALUE=DATE-TIME:20261028T183000Z
DTSTAMP;VALUE=DATE-TIME:20261022T234122Z
UID:indico-contribution-50-3681@nyx.physics.mcgill.ca
DESCRIPTION:Speakers: Nick Beavis (University of Toronto)\nInflation is a 
 proposed period of accelerated expansion in the early universe\, providing
  a mechanism for generating the primordial fluctuations that seeded cosmic
  structure. Many inflationary models are able to match the large-scale obs
 ervations of the CMB and LSS\, whilst differing in their dynamics and smal
 l-scale characteristics. Nonlinear effects could provide additional inform
 ation about inflationary dynamics\, motivating methods that retain nonline
 ar field evolution such as lattice simulations. For the theoretically well
 -motivated slow-roll $\\alpha$-attractor models\, however\, the nonlinear 
 corrections are expected to be small\, making their numerical resolution c
 hallenging. We used InflationEasy to study E/T-model $\\alpha$-attractor i
 nflation\, testing whether a lattice framework could resolve departures fr
 om linear theory and differences between these models\, after accounting f
 or numerical sensitivity. \n\nOur pipeline was validated against a publish
 ed ultra-slow-roll benchmark. A numerical sensitivity study\, varying spat
 ial resolution\, box size and integration parameters\, identified restrict
 ed wavenumber ranges with $1\\%-5\\%$ numerical sensitivity in the curvatu
 re and post-inflationary scalar-induced GW spectra. A comparison of the E-
 model lattice results with a homogeneous-background evolution found no num
 erically resolved backreaction\, while curvature power spectra agreed with
  linear theory within numerical sensitivity. A model normalisation test sh
 owed that replacing a common leading-order normalisation with model-specif
 ic normalisations reduced the observed differences in E/T-model results be
 low numerical sensitivity.\n\nThese results demonstrate the difficulty of 
 resolving nonlinearity and differences between models for highly perturbat
 ive slow-roll inflationary models\, and highlight the importance of numeri
 cal control and consistent model normalisation when interpreting small dif
 ferences between inflationary predictions.\n\nhttps://nyx.physics.mcgill.c
 a/event/587/contributions/3681/
LOCATION:Online 
URL:https://nyx.physics.mcgill.ca/event/587/contributions/3681/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Constraining Modified Gravity with the Marked Power Spectrum
DTSTART;VALUE=DATE-TIME:20261028T182500Z
DTEND;VALUE=DATE-TIME:20261028T182600Z
DTSTAMP;VALUE=DATE-TIME:20261022T234122Z
UID:indico-contribution-50-3712@nyx.physics.mcgill.ca
DESCRIPTION:Speakers: Amani Hussien (University of Toronto)\nThe nature of
  cosmic acceleration remains an open question\, with Modified Gravity (MG)
  providing an alternative to dark energy models within General Relativity.
  Cosmic voids are particularly sensitive tracers of MG and their two-point
  clustering captures higher order density field statistics. Since conventi
 onal two-point statistics are primarily dominated by overdensities\, we us
 e the marked power spectrum\, which reweights the matter overdensity field
  to enhance information from voids. We first verify that the MG boost from
  COLA (COmoving Lagrangian Acceleration) simulations is comparable to that
  from corresponding full N-body simulations for the marked power spectrum 
 and cross-spectrum within ~1%. We further show that this agreement holds a
 cross a range of mark definitions. Since the marked field contains non-Gau
 ssian information\, we develop a simulation-based inference (SBI) pipeline
  using a Neural Posterior Estimator (NPE) to constrain phenomenological MG
  (μ\, η) and cosmological parameters (Ωm\, As). We test this pipeline b
 y performing parameter inference on 500 Lognormal Mock and 150 MGCOLA simu
 lations. Our results demonstrate the feasibility of using the marked power
  spectrum within the SBI framework to constrain MG and cosmological parame
 ters. This framework has the potential to extract additional information f
 rom underdense regions and improve MG constraints by combining CMB lensing
  maps with marked void statistics.\n\nhttps://nyx.physics.mcgill.ca/event/
 587/contributions/3712/
LOCATION:Online 
URL:https://nyx.physics.mcgill.ca/event/587/contributions/3712/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Developing a Machine Learning Algorithm for Dark Matter Detection 
 in the SuperCDMS Experiment
DTSTART;VALUE=DATE-TIME:20261028T182400Z
DTEND;VALUE=DATE-TIME:20261028T182500Z
DTSTAMP;VALUE=DATE-TIME:20261022T234122Z
UID:indico-contribution-50-3705@nyx.physics.mcgill.ca
DESCRIPTION:Speakers: Lyssa Dale-Davies (University of Toronto)\nThe natur
 e of dark matter is among the most longstanding mysteries in physics and a
 stronomy\, with its detection potentially enabling a deeper understanding 
 of physics beyond the standard model. One of the most promising candidates
  for dark matter is the weakly interacting massive particle (WIMP)\, which
  has become the subject of various dark matter searches across the world. 
 The Super Cryogenic Dark Matter Search (SuperCDMS) experiment uses cylindr
 ical crystals as detectors equipped with six superconducting sensors on ei
 ther end that enable excellent energy resolution and sensitivity to potent
 ial dark matter masses as low as the eV scale. Determining the position in
 formation of particle detection events is made complicated by the crystal 
 and sensor setup\, making tools like machine learning ideal. My research h
 as focused on developing a machine learning algorithm to predict position 
 information for a set of calibration data. The model I used was trained on
  a Monte Carlo simulation of the detector\, with a large component of my w
 ork being the application of different scaling methods to better model rea
 l data and hence produce a more accurate model. While the development of t
 he algorithm is still ongoing\, key results have been the model's success 
 in predicting the position information of the calibration data as well as 
 performing well when evaluated on metrics like energy prediction. In futur
 e studies\, this model will be instrumental in analyzing data from the det
 ector\, which will further our understanding of dark matter\, what its mas
 s could and couldn’t be\, and the limitations of superconducting detecto
 r physics.\n\nhttps://nyx.physics.mcgill.ca/event/587/contributions/3705/
LOCATION:Online 
URL:https://nyx.physics.mcgill.ca/event/587/contributions/3705/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The Long and Winding Equation: Symbolic Regression for Power Spect
 ra from the Cosmic Dawn and Epoch of Reionization
DTSTART;VALUE=DATE-TIME:20261028T182300Z
DTEND;VALUE=DATE-TIME:20261028T182400Z
DTSTAMP;VALUE=DATE-TIME:20261022T234122Z
UID:indico-contribution-50-3694@nyx.physics.mcgill.ca
DESCRIPTION:Speakers: Maria Bayder (McGill University)\nThe formation of f
 irst-generation stars and galaxies marks the onset of Cosmic Dawn. The Epo
 ch of Reionization ensues when these structures emit ultraviolet light tha
 t ionizes neutral hydrogen in the universe. Although these epochs are some
  of the least understood\, the 21 cm signal\, which is emitted from the sp
 in flip transition of neutral hydrogen's ground state\, is a promising pro
 be for them. The power spectrum\, defined as the Fourier transform of the 
 two-point correlation\, measures the amplitude of this signal and can be d
 irectly obtained by radio telescopes. In this work\, we aim to identify ho
 w various physical parameters influence this power spectrum by finding an 
 interpretable\, compact equation that describes it. We use AMBER\, a semi-
 numerical code\, to simulate neutral and ionized hydrogen maps between red
 shifts 5 and 15. We vary the physical parameters in this code and generate
  power spectra for each parameter set in the stated redshift range. We the
 n apply symbolic regression\, a machine-learning algorithm that computes a
  best-fit equation to given data. We use the PySR library that implements 
 this algorithm and obtain the power spectrum as a function of physical par
 ameters. Our current best-fit equations contain redshift\, spatial frequen
 cy\, and most physical parameters as arguments. The mean squared error of 
 these equations is found to be of the order of 0.01 compared to AMBER’s 
 results. This work shows an independent way of understanding how various p
 hysical effects shape the power spectrum throughout Cosmic Dawn and reioni
 zation.\n\nhttps://nyx.physics.mcgill.ca/event/587/contributions/3694/
LOCATION:Online 
URL:https://nyx.physics.mcgill.ca/event/587/contributions/3694/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The impact of nearby soil conditions on the MIST global 21-cm expe
 riment
DTSTART;VALUE=DATE-TIME:20261028T182200Z
DTEND;VALUE=DATE-TIME:20261028T182300Z
DTSTAMP;VALUE=DATE-TIME:20261022T234122Z
UID:indico-contribution-50-3717@nyx.physics.mcgill.ca
DESCRIPTION:Speakers: Francis McGee (McGill University)\nGlobal 21-cm expe
 riments are designed to capture the sky-averaged 21-cm signal emitted by n
 eutral hydrogen and use it to probe the conditions present during the earl
 iest epochs of the universe. Other experiments\, such as EDGES and SARAS 3
 \, probe the signal produced during the era of cosmic dawn\; however\, the
 ir reported results are in tension with each other. One proposed explanati
 on for the EDGES feature is systematic effects associated with the finite 
 metal ground plane beneath the antenna.\nThe Mapper of the Intergalactic M
 edium (IGM) Spin Temperature (MIST) is a global 21-cm experiment located i
 n the radio-quiet Canadian High Arctic. MIST is designed to provide an ind
 ependent probe of the cosmic dawn signal without a fixed ground plane\, re
 lying on careful electrical modeling of the soil beneath the antenna. Past
  work for MIST has treated the soil as laterally homogeneous and extending
  infinitely horizontally.\nWe will present an overview of the MIST experim
 ent\, along with results from new simulations focusing on the impact of so
 il surface features on the recovered global signal. Three cases will be ex
 amined: individual rocks on the surface\, a selection of rocks scattered a
 cross the surface\, and undulating soil mimicking smooth Arctic surface co
 nditions. Each case will be examined using soil parameter combinations spa
 nning representative Arctic soil conditions around the antenna.\nThe findi
 ngs presented have applicability beyond the MIST experiment and the global
  21-cm community\, informing more traditional experiments about the behavi
 or of soils beyond the edges of their ground planes.\n\nhttps://nyx.physic
 s.mcgill.ca/event/587/contributions/3717/
LOCATION:Online 
URL:https://nyx.physics.mcgill.ca/event/587/contributions/3717/
END:VEVENT
BEGIN:VEVENT
SUMMARY:BEAMS with Bias Correction: Is It Well-Calibrated?
DTSTART;VALUE=DATE-TIME:20261028T182100Z
DTEND;VALUE=DATE-TIME:20261028T182200Z
DTSTAMP;VALUE=DATE-TIME:20261022T234122Z
UID:indico-contribution-50-3696@nyx.physics.mcgill.ca
DESCRIPTION:Speakers: Linh Vo ()\nType Ia supernovae (SNe Ia) are importan
 t standardizable candles used to measure cosmic distances and constrain th
 e expansion rate of the universe. A central challenge in analyzing these t
 ransients is Malmquist bias\, which the Bayesian Estimation Applied to Mul
 tiple Species (BEAMS) with Bias Correction (BBC) framework aims to correct
 . While BBC yields unbiased cosmological constraints for small samples\, i
 ts underlying BiasCor lookup table may fail to maintain performance as sam
 ple sizes scale up significantly.\nIn this work\, we evaluate the calibrat
 ion of the BBC framework using backward simulation-based inference. We sim
 ulate surveys containing 2\,000\, 5\,000\, and 20\,000 pure SNe Ia under t
 he precise cosmological model assumed by the BBC BiasCor table. Passing th
 ese samples through the BBC pipeline\, we perform Simulation-Based Calibra
 tion (SBC) to test whether the framework is properly calibrated.\nEven wit
 hin this idealized setting – no sample contamination and model misspecif
 ication – we show that the BiasCor component introduces systematic overc
 onfidence that worsens as sample size increases. Furthermore\, the BiasCor
  correction interacts with the parameter degeneracy to underestimate uncer
 tainty specifically along that axis rather than uniformly. As next-generat
 ion surveys like the Vera C. Rubin Observatory dramatically scale up SNe I
 a datasets\, these findings highlight important limitations in the current
  BBC pipeline and motivate the development of scalable and fully calibrate
 d frameworks.\n\nhttps://nyx.physics.mcgill.ca/event/587/contributions/369
 6/
LOCATION:Online 
URL:https://nyx.physics.mcgill.ca/event/587/contributions/3696/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Inferring supernova light curves in Rubin data
DTSTART;VALUE=DATE-TIME:20261028T182000Z
DTEND;VALUE=DATE-TIME:20261028T182100Z
DTSTAMP;VALUE=DATE-TIME:20261022T234122Z
UID:indico-contribution-50-3693@nyx.physics.mcgill.ca
DESCRIPTION:Speakers: Connor Stone (University of Toronto)\nThe Vera C. Ru
 bin observatory is the premier optical transient facility on sky today. Ma
 ny transient sources are point sources embedded in a host galaxy. This nec
 essitates the subtraction of that host's light before examining the bright
 ness over time\, light curve\, of the transient. Standard practice is to s
 tack images from before the transient to then subtract and reveal the chan
 ging light curve. While this is fast and fairly reliable\, it is provably 
 sub-optimal compared to fully forward modelling the scene and transient si
 multaneously. Here we present an AstroPhot model in JAX that does just thi
 s to extract reliable and physically realistic light curves. I will discus
 s the progress so far and tests to compare with difference imaging.\n\nhtt
 ps://nyx.physics.mcgill.ca/event/587/contributions/3693/
LOCATION:Online 
URL:https://nyx.physics.mcgill.ca/event/587/contributions/3693/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The Polarization and Magnetic Field of the Radio Arc as Observed b
 y ALMA at 100 GHz
DTSTART;VALUE=DATE-TIME:20261028T181900Z
DTEND;VALUE=DATE-TIME:20261028T182000Z
DTSTAMP;VALUE=DATE-TIME:20261022T234122Z
UID:indico-contribution-50-3692@nyx.physics.mcgill.ca
DESCRIPTION:Speakers: Nora Salem ()\nThe unique Galactic Center non-therma
 l filaments (NTFs) have been a focus of investigations for over 40 years. 
 The most prominent manifestation of the NTFs is a bundle of parallel filam
 ents known as the Radio Arc. Radio polarimetric observations made with the
  Very Large Array (VLA) at 10 GHz have revealed an alternating magnetic fi
 eld pattern in the Radio Arc that could either be a result of multiple fie
 ld systems being encountered along the line of sight or an intrinsic featu
 re of the Radio Arc. These VLA observations were not able to distinguish b
 etween these possibilities due to the large rotation measures encountered 
 towards the source. We present ALMA 100 GHz observations of the Radio Arc 
 that are not impacted by significant Faraday effects. The observations rep
 orted here represent both the first time that ALMA has been used to study 
 the NTFs and the first time 100 GHz polarimetric observations have been co
 nducted on the Radio Arc. We find a uniformly rotated magnetic field with 
 respect to the NTF filament orientation\, with the angle of rotation being
  constant along the length of each filament. However\, we find a systemati
 cally different magnetic field orientation in different Radio Arc filament
 s. We use this field pattern to update our understanding of the line-of-si
 ght structures local to the Radio Arc. We find that the magnetic field inf
 erred from our ALMA observations is likely a result either of confusion fr
 om multiple magnetic field systems or because the polarization is centrall
 y concentrated within the NTF filaments.\n\nhttps://nyx.physics.mcgill.ca/
 event/587/contributions/3692/
LOCATION:Online 
URL:https://nyx.physics.mcgill.ca/event/587/contributions/3692/
END:VEVENT
BEGIN:VEVENT
SUMMARY:SN2024uwq and the Evolutionary History of Type IIb Supernovae
DTSTART;VALUE=DATE-TIME:20261028T181800Z
DTEND;VALUE=DATE-TIME:20261028T181900Z
DTSTAMP;VALUE=DATE-TIME:20261022T234122Z
UID:indico-contribution-50-3701@nyx.physics.mcgill.ca
DESCRIPTION:Speakers: Annalisa Teixeira ()\nYellow Supergiants have been o
 bserved exploding as Type IIb Supernovae (SNe)\, which is not predicted by
  standard single-star evolution models. The evolutionary history of these 
 progenitors is still highly debated\, however\, there is tentative evidenc
 e for two Type IIb progenitor classifications – those with compact versu
 s extended radii – which have different mass-loss histories. Early optic
 al data\, which constrains the progenitor's mass and radius\, can be compl
 emented with radio light curve data that probes the circumstellar medium (
 CSM) to explore the evolutionary history and properties of these progenito
 rs. Using synchrotron self-absorption models\, we perform this analysis on
  the nearby Type IIb supernova SN2024uwq. Further\, we compare SN2024uwq t
 o other Type IIb supernovae with early detection data and binary stellar e
 volution models to assess population-level trends. We determine that SN202
 4uwq has a wind-like CSM with a seemingly more compact progenitor\, which 
 leads to higher windspeeds in contrast to the rest of our catalogue. Compa
 ring the evolutionary histories of these supernovae\, we find that SN2024u
 wq may indicate that there are intermediate Type IIb Supernovae\, or that 
 the proposed extended versus compact classification is a continuum.\n\nhtt
 ps://nyx.physics.mcgill.ca/event/587/contributions/3701/
LOCATION:Online 
URL:https://nyx.physics.mcgill.ca/event/587/contributions/3701/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sub-band Extensions to Measure Scattering with the Arrival-Times P
 ipeline for Repeating Fast Radio Bursts
DTSTART;VALUE=DATE-TIME:20261028T181700Z
DTEND;VALUE=DATE-TIME:20261028T181800Z
DTSTAMP;VALUE=DATE-TIME:20261022T234122Z
UID:indico-contribution-50-3704@nyx.physics.mcgill.ca
DESCRIPTION:Speakers: Victor Pop (McMaster University)\nFast radio bursts 
 (FRBs) are millisecond-duration extragalactic radio transients\, a subset 
 of which repeat. Multipath propagation through ionized media convolves eac
 h burst with a one-sided exponential\, producing a scattering tail whose t
 imescale scales steeply with frequency\, τ ∝ ν^α with α ≈ −4. An
  observed burst width\, however\, also carries contributions from intrinsi
 c emission\, instrumental sampling\, residual dispersion\, drift smearing\
 , and unresolved sub-bursts\, several of which produce asymmetric profiles
 .\nSub-band methods have been widely used to estimate FRB scattering. Here
  we present a sub-band extension to the per-channel arrival-times pipeline
  of Chamma et al. (2025)\, designed to estimate scattering only where the 
 data support it. Each profile is fit with an exponentially modified Gaussi
 an (EMG)\, with an FRBs spectral bandwidth further divided into dedrifted 
 sub-bands. The recovered tail timescales are fit with a power law\, where 
 only an index within the empirical range −4.4 ≤ α ≤ −3.6 licenses
  a scattering interpretation.\nAs a preliminary single-burst demonstration
 \, we apply the pipeline to FRB 20210415C from the second CHIME/FRB repeat
 er catalogue. Seven sub-bands across 420–760 MHz yield α = −3.94 ± 0
 .12\, consistent with thin-screen scattering. Initial tests on simulated b
 ursts suggest the index is robust. While these results are preliminary\, w
 e estimate that the scattering tail exceeds Galactic model predictions alo
 ng this sightline by ~400×\, pointing to non-Galactic scattering. This wo
 rk highlights the importance of further efforts to separate scattering fro
 m other broadening processes.\n\nhttps://nyx.physics.mcgill.ca/event/587/c
 ontributions/3704/
LOCATION:Online 
URL:https://nyx.physics.mcgill.ca/event/587/contributions/3704/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Characterizing Fast Radio Burst morphologies in CHIME’s Baseband
  Catalog 2
DTSTART;VALUE=DATE-TIME:20261028T181600Z
DTEND;VALUE=DATE-TIME:20261028T181700Z
DTSTAMP;VALUE=DATE-TIME:20261022T234122Z
UID:indico-contribution-50-3686@nyx.physics.mcgill.ca
DESCRIPTION:Speakers: Chloé Legué (McGill University\, Trottier Space In
 stitute)\nFast radio bursts (FRBs) are millisecond-duration radio transien
 ts originating at extra-galactic distances. Their morphologies\, the signa
 l’s evolution as a function of time and frequency\, encode valuable info
 rmation about their emission physics as well as intervening plasma and mag
 netic fields. For example\, we aim to measure the temporal spacing between
  sub-bursts\, their changes in bandwidth and their asymmetry. This constra
 ins theoretical emission models and provides direct measurements of the co
 lumn density and clumpiness of ionized matter along the line of sight. Two
  main streams of data are recorded by the Canadian Hydrogen Intensity Mapp
 ing Experiment (CHIME) telescope: intensity at 1ms cadence and raw voltage
  (baseband) at 2.56µs cadence. CHIME recently released its second Catalog
  of FRBs at intensity resolution\, containing over 4500 events. The upcomi
 ng Baseband Catalog 2 of CHIME includes a sample of Catalog 2 FRBs\, conta
 ining over 2000 events\, allowing us to study a population of multi-compon
 ent and complex events. In this talk\, I will present our current morpholo
 gy pipeline using fitburst\, a least-squares fitter that uses both exponen
 tially modified Gaussian sub-bursts and a running power law. I will presen
 t preliminary results obtained with this pipeline and show correlations be
 tween different morphological parameters.\n\nhttps://nyx.physics.mcgill.ca
 /event/587/contributions/3686/
LOCATION:Online 
URL:https://nyx.physics.mcgill.ca/event/587/contributions/3686/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Modelling the Energy and Redshift distribution of FRBs using the S
 econd CHIME/FRB catalog
DTSTART;VALUE=DATE-TIME:20261028T181500Z
DTEND;VALUE=DATE-TIME:20261028T181600Z
DTSTAMP;VALUE=DATE-TIME:20261022T234122Z
UID:indico-contribution-50-3709@nyx.physics.mcgill.ca
DESCRIPTION:Speakers: Naman Jain (McGill University)\nFast radio bursts (F
 RBs) are energetic millisecond-duration bursts with extragalactic origins.
  Roughly 4000 unique sources have been observed to date\, about 3% of whic
 h have been seen to repeat\, though it remains unclear whether all FRBs re
 peat.\nAn FRB population study addresses several key questions: How often 
 do FRBs occur in the universe? What energy and redshift distributions do t
 hey follow? Is their occurrence correlated with the cosmic star formation 
 history (SFH)? Answering these questions helps contextualize the origins o
 f FRBs with potential astrophysical sources such as magnetars and supernov
 ae.\nPrevious population studies\, based on samples of a few hundred sourc
 es\, have provided important constraints on FRB rates and energetics. Howe
 ver\, these analyses were limited by smaller sample sizes\, less well-char
 acterized selection effects\, and uncertain treatment of repeat bursts.\nT
 he recently released Second CHIME/FRB Catalog contains more than 90% of al
 l known FRB sources (≈3600) and provides well-calibrated selection effec
 ts. We leverage this sample to infer key FRB properties\, including the vo
 lumetric rate\, energy function\, redshift distribution\, and correlation 
 with the cosmic SFH. We then compare the predicted energetics and abundanc
 es with proposed FRB models and contrast the inferred redshift distributio
 ns with those of FRBs with known host galaxies.\n\nhttps://nyx.physics.mcg
 ill.ca/event/587/contributions/3709/
LOCATION:Online 
URL:https://nyx.physics.mcgill.ca/event/587/contributions/3709/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Investigating Relativistic Jets in X-ray Binaries through Multi-Wa
 velength Timing Studies
DTSTART;VALUE=DATE-TIME:20261028T180500Z
DTEND;VALUE=DATE-TIME:20261028T181500Z
DTSTAMP;VALUE=DATE-TIME:20261022T234122Z
UID:indico-contribution-50-3628@nyx.physics.mcgill.ca
DESCRIPTION:Speakers: Élodie Lescure (University of Lethbridge)\nRelativi
 stic jets launched from accreting compact objects are thought to play an i
 mportant role in the Universe\, influencing large-scale processes such as 
 galaxy evolution and star formation. However\, the connection between thei
 r properties and those of the accretion flow remains poorly understood. Mu
 lti-wavelength time-domain observations of black hole X-ray binaries provi
 de a new avenue to study this connection in detail. By probing different c
 omponents of the system at different wavelengths\, these observations allo
 w us to trace the evolution of gas from inflow to outflow. Recently\, we l
 aunched a first-of-its-kind observational program designed to obtain multi
 -wavelength time-domain observations spanning an entire X-ray binary outbu
 rst. In this talk\, I will present the first results from this program\, i
 ncluding recent ALMA and VLT observations of BW Cir (GS 1354-64).\n\nhttps
 ://nyx.physics.mcgill.ca/event/587/contributions/3628/
LOCATION:Online 
URL:https://nyx.physics.mcgill.ca/event/587/contributions/3628/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mapping Magnetic Field Structure in Galactic Supernova Remnants wi
 th ASKAP
DTSTART;VALUE=DATE-TIME:20261028T175500Z
DTEND;VALUE=DATE-TIME:20261028T180500Z
DTSTAMP;VALUE=DATE-TIME:20261022T234122Z
UID:indico-contribution-50-3647@nyx.physics.mcgill.ca
DESCRIPTION:Speakers: Gabrielle Graham (University of Alberta)\nPolarizati
 on observations provide a unique opportunity to probe the geometry and str
 ucture of astrophysical magnetic fields. In the Milky Way\, Supernova remn
 ants (SNRs) are a key environment for connecting polarized emission to the
  physical processes tied to shaping the magnetic field: shocks\, turbulenc
 e\, and instabilities. By studying the organization of the on-sky polariza
 tion angle (PA) in SNRs\, we are able to directly investigate the structur
 e of the local magnetic field. Past radio observations of Galactic SNRs ha
 ve been limited by sky coverage or resolution. However\, with new observat
 ions from the Australian Square Kilometre Array Pathfinder (ASKAP) telesco
 pe\, we are able to study the polarization properties of Galactic SNRs in 
 unprecedented detail across the entire southern sky. Here\, we present an 
 in-depth study of the on-sky magnetic field structure for seven Galactic S
 NRs. We use radio polarization and continuum data from the Polarization Sk
 y Survey of the Universe’s Magnetism (POSSUM) and the Evolutionary Map o
 f the Universe (EMU) surveys. We derive on-sky magnetic field maps for the
  seven SNRs from the recovered intrinsic polarization angles. We also quan
 tify the uncertainties in the intrinsic polarization angle measurements du
 e to the differential rotation induced by the Faraday effect. Our on-sky m
 agnetic field maps serve as an important foundation for future work mappin
 g the three-dimensional magnetic field structure of the Galaxy.\n\nhttps:/
 /nyx.physics.mcgill.ca/event/587/contributions/3647/
LOCATION:Online 
URL:https://nyx.physics.mcgill.ca/event/587/contributions/3647/
END:VEVENT
BEGIN:VEVENT
SUMMARY:An Aspherical Circumstellar Medium Surrounding Double-peaked Ic-BL
  SN2022xxf
DTSTART;VALUE=DATE-TIME:20261028T174500Z
DTEND;VALUE=DATE-TIME:20261028T175500Z
DTSTAMP;VALUE=DATE-TIME:20261022T234122Z
UID:indico-contribution-50-3662@nyx.physics.mcgill.ca
DESCRIPTION:Speakers: Sam Lakerdas-Gayle (Cornell Center for Astrophysics 
 and Planetary Science)\nStripped-envelope core-collapse supernovae are the
  violent explosions that mark the death of a massive star that had some or
  all of its outer H and He layers stripped off. One class of stripped-enve
 lope supernovae is the rare Type Ic-BL\; these are the only events associa
 ted with the detection of a long-duration gamma-ray bursts\, but it is sti
 ll unclear why only some Ic-BLs accompany a gamma-ray burst detection. Rad
 io observations probe the gas in the vicinity of a supernova\, which conte
 xtualizes the lives of highly stripped stars and can tell us about which s
 tars may produce a gamma-ray burst. In this talk\, I will present radio ob
 servations of SN2022xxf\, the nearest Ic-BL to date and discuss how its do
 uble-peaked light curve reveals the complex stripping mechanisms that shap
 e these rare events.\n\nhttps://nyx.physics.mcgill.ca/event/587/contributi
 ons/3662/
LOCATION:Online 
URL:https://nyx.physics.mcgill.ca/event/587/contributions/3662/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Evaluating magnetars as the progenitors of fast radio bursts
DTSTART;VALUE=DATE-TIME:20261028T173500Z
DTEND;VALUE=DATE-TIME:20261028T174500Z
DTSTAMP;VALUE=DATE-TIME:20261022T234122Z
UID:indico-contribution-50-3657@nyx.physics.mcgill.ca
DESCRIPTION:Speakers: Vishwangi Shah ()\nFast radio bursts (FRBs) are micr
 o-to-millisecond-duration radio transients originating from extragalactic 
 distances. While thousands of FRBs have been detected\, their origins rema
 in unknown. Many FRB theories invoke highly magnetised neutron stars\, cal
 led magnetars\, as FRB progenitors. In this talk\, I will evaluate the mag
 netar progenitor scenario using recent results from the CHIME/FRB telescop
 e.\nThe most energetic FRBs provide crucial insights into their emission m
 echanisms and progenitor models. I will present constraints on the maximum
  energy of FRBs derived from the largest sample of ~3\,000 one-off bursts 
 in the second CHIME/FRB catalog. Our results indicate that the isotropic e
 nergies of the most energetic FRBs are collectively limited to ~$10^{42}$ 
 erg\, thereby constraining the energy reservoir of their sources. Under st
 andard assumptions for the radiative efficiency factor between radio and h
 igh-energy emission\, this energy limit is consistent with the energies of
  the most powerful magnetar giant flares.\nFurthermore\, the occurrence of
  most FRB sources inside star-forming galaxies supports an origin in magne
 tars formed via core-collapse supernovae. However\, I will present the fir
 st ever localization of a repeating FRB far outside a quiescent galaxy\, w
 hich challenges this theory. We propose that this source resides in a glob
 ular cluster\, where the magnetar progenitor scenario is only viable if th
 e magnetar formed via exotic formation channels such as compact-object mer
 gers.\n\nhttps://nyx.physics.mcgill.ca/event/587/contributions/3657/
LOCATION:Online 
URL:https://nyx.physics.mcgill.ca/event/587/contributions/3657/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The CHIME All-Sky Multiday Pulsar Stacking Search (CHAMPSS)
DTSTART;VALUE=DATE-TIME:20261028T172500Z
DTEND;VALUE=DATE-TIME:20261028T173500Z
DTSTAMP;VALUE=DATE-TIME:20261022T234122Z
UID:indico-contribution-50-3638@nyx.physics.mcgill.ca
DESCRIPTION:Speakers: Lars Kuenkel (McGill University)\nThe Canadian Hydro
 gen Intensity Mapping Experiment (CHIME) has been an instrumental telescop
 e in shaping our understand of transient sky by detecting the vast majorit
 y of known fast radio bursts (FRBs) using its CHIME/FRB backend. The recen
 tly launched CHIME All-Sky Multiday Pulsar Stacking Search (CHAMPSS) uses 
 data from this backend to perform a pulsar periodicity search with unprece
 dented cadence. In the current configuration we are able to observe about 
 20% daily of the northern sky which allows us to probe very intermittent s
 ources.\n\nCHAMPSS is not only a pulsar survey with a high cadence\, but o
 ur daily allow observations allow us a deep search for faint sources by co
 mbining hundreds of observations. We do this by performing power spectra s
 tacking. This approach of doing daily searches combined with searches in o
 ur combined power spectra stacks has allowed us to find more than 60 pulsa
 rs so far. These new pulsars include binary pulsars\, intermittent sources
  and some of the closest pulsars known to date.\n\nI will explain the uniq
 ue challenges and opportunities of our survey and outline our survey pipel
 ine\, including recent developments that allow us to be more sensitive to 
 binary pulsars.\n\nI will also highlight some of our most exciting pulsar 
 discoveries that we have made so far.\n\nhttps://nyx.physics.mcgill.ca/eve
 nt/587/contributions/3638/
LOCATION:Online 
URL:https://nyx.physics.mcgill.ca/event/587/contributions/3638/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Constraining the evolution of dynamic environments surrounding act
 ively repeating fast radio bursts
DTSTART;VALUE=DATE-TIME:20261028T171500Z
DTEND;VALUE=DATE-TIME:20261028T172500Z
DTSTAMP;VALUE=DATE-TIME:20261022T234122Z
UID:indico-contribution-50-3667@nyx.physics.mcgill.ca
DESCRIPTION:Speakers: Nicole Mulyk (McGill University)\nFast radio bursts 
 (FRBs) are short-duration (ms)\, bright (Jy-kJy) bursts of radio emission\
 , generally originating from cosmological distances. Although thousands of
  FRB events have been published\, the progenitor and emission mechanism of
  FRBs are still not well understood. While most FRBs appear to be one-off 
 events\, ~2% of FRBs have been observed to repeat. The Canadian Hydrogen I
 ntensity Mapping Experiment (CHIME) radio telescope has detected thousands
  of FRBs\, monitoring a large number of repeaters over multi-year baseline
 s with a daily cadence. Radio spectra of FRBs are uniquely able to probe t
 he properties of the plasma in the FRBs' immediate vicinity. CHIME/FRB’s
  high time resolution (2.56 μs) and broadband\, low-frequency coverage ma
 ke CHIME/FRB ideal for constraining propagation effects and monitoring the
 m over time. Recent works have discovered secular evolution of the magneti
 zed plasma surrounding a few peculiar repeating FRBs\, linking them to you
 ng stellar remnants of massive stars. Our project builds on this work by m
 easuring changes in the magnetoionic plasma over a timescale of months to 
 years\, for a diverse sample of ~50 repeaters observed by CHIME/FRB. By ex
 amining changes in the magnetoionic plasma for a larger population of repe
 aters\, we aim to establish boundaries on the potential progenitor or envi
 ronment for the general population of repeating FRBs.\n\nhttps://nyx.physi
 cs.mcgill.ca/event/587/contributions/3667/
LOCATION:Online 
URL:https://nyx.physics.mcgill.ca/event/587/contributions/3667/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Evidence for the invisible gas around galaxy halos using fast radi
 o bursts from CHIME/FRB
DTSTART;VALUE=DATE-TIME:20261028T170500Z
DTEND;VALUE=DATE-TIME:20261028T171500Z
DTSTAMP;VALUE=DATE-TIME:20261022T234122Z
UID:indico-contribution-50-3623@nyx.physics.mcgill.ca
DESCRIPTION:Speakers: Affan Khadir (McGill University)\nMost of the baryon
 ic mass in galaxy halos consists of diffuse\, magnetized plasma\, which is
  referred to as the circumgalactic medium (CGM). The properties of the CGM
  remain relatively unconstrained\, as the low density of the gas makes it 
 hard to image in most wavelengths of the electromagnetic spectrum. Fast ra
 dio bursts (FRBs) are thus incredibly good probes of this plasma\, because
  they undergo dispersion as they propagate through the CGM.\n \nI used ove
 r 1600 FRB DMs from CHIME/FRB's upcoming Baseband Catalog 2\, which is the
  largest catalog of FRBs that have a localization error of $<1'$\, to cond
 uct an unprecedented statistical study of nearby galaxy halos. In doing so
 \, I obtained the strongest evidence ($p = 0.0053\;\\sim 2.6\\sigma$) for 
 a DM excess due to the CGM to date\, with an amplitude of $119\\pm43\\\,$p
 c$~$cm$^{-3}$. I also obtained some of the first FRB-based constraints of 
 the baryon distribution of the CGM of Milky Way like galaxies\, with tenta
 tive evidence ($\\sim2.4\\sigma$) that galaxy halos in this mass range may
  be more relaxed than previously thought\, almost tracing the underlying d
 ark matter distribution directly. However\, more FRBs are needed to furthe
 r test this. My work demonstrates the power of FRBs to map the invisible d
 iffuse plasma in the Universe and forecasts a $5\\sigma$ detection of the 
 CGM with 10000 FRBs\, which can then be used to place the best constraints
  (amongst all probes of hot plasma) on the distribution of baryons in the 
 CGM.\n\nhttps://nyx.physics.mcgill.ca/event/587/contributions/3623/
LOCATION:Online 
URL:https://nyx.physics.mcgill.ca/event/587/contributions/3623/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Probing the Origins of Fast Radio Bursts Through Searches for Mult
 i-wavelength Counterparts
DTSTART;VALUE=DATE-TIME:20261028T165500Z
DTEND;VALUE=DATE-TIME:20261028T170500Z
DTSTAMP;VALUE=DATE-TIME:20261022T234122Z
UID:indico-contribution-50-3632@nyx.physics.mcgill.ca
DESCRIPTION:Speakers: Melanie Szpigiel (McGill University)\nFast Radio Bur
 sts (FRBs) are highly energetic\, ~millisecond duration bursts of radio em
 ission with extragalactic origins that were discovered nearly 19 years ago
 . While there is some evidence suggesting FRBs may originate from magnetar
 s\, there still remains the question of whether all FRBs are produced by m
 agnetars. One potential method for further understanding FRB progenitors i
 s through cross-matching FRBs with different transients with a known proge
 nitor by searching for positional\, redshift\, and/or temporal coincidence
 s. In this talk\, I will discuss a new pipeline for the Canadian Hydrogen 
 Intensity Mapping Experiment (CHIME) which automatically cross-matches all
  FRB candidates with gamma-ray bursts (GRBs) detected by the Swift observa
 tory and Fermi telescope\,  gravitational waves (GWs) detected by the Ligo
 -Virgo-Kagra (LVK) collaboration\, and optical transients reported in the 
 Transient Name Server (TNS). I will also describe the largest campaign to 
 cross-match over 4000 FRBs with all known gamma-ray bursts (GRBs) to deter
 mine radio upper limits for GRBs within CHIME’s field of view. Finally\,
  I will discuss the results of FRB-TNS optical transient crossmatching as 
 a direct test to the FRB progenitor model.\n\nhttps://nyx.physics.mcgill.c
 a/event/587/contributions/3632/
LOCATION:Online 
URL:https://nyx.physics.mcgill.ca/event/587/contributions/3632/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Off-axis GRBs and Where to Find Them
DTSTART;VALUE=DATE-TIME:20261028T164500Z
DTEND;VALUE=DATE-TIME:20261028T165500Z
DTSTAMP;VALUE=DATE-TIME:20261022T234122Z
UID:indico-contribution-50-3629@nyx.physics.mcgill.ca
DESCRIPTION:Speakers: Genevieve Schroeder ()\nLong-duration gamma-ray burs
 ts (GRBs) are the most luminous explosions in the Universe\, visible out t
 o cosmological redshifts. Almost every spectroscopically confirmed superno
 va (SN) associated with a long GRB has been hydrogen and helium poor with 
 broad lines (Ic-bl)\, indicating a stripped massive star progenitor with f
 ast winds that produced a highly-collimated jet viewed on-axis. A critical
  prediction of this progenitor model is that there should be a large numbe
 r of off-axis jets accompanying SNe Ic-bl - however\, this has yet to be o
 bservationally confirmed. Additionally\, if a GRB is observed moderately o
 ff-axis\, it may result in a spectrally softer X-ray flash (XRFs)\, detect
 able with X-ray observatories such as Einstein Probe and SVOM. Radio obser
 vations of XRFs and SNe Ic-bl can reveal late rising afterglows as the jet
  spreads into the field of view\, providing one of the best pieces of evid
 ence for the off-axis GRB scenario. Here\, I will present recent results f
 ollowing up several candidate off-axis GRBs\, including an XRF and a sampl
 e of radio loud SNe Ic-bl. Additionally\, I will lay the path forward to d
 etecting off-axis GRBs in the era of large transient surveys.\n\nhttps://n
 yx.physics.mcgill.ca/event/587/contributions/3629/
LOCATION:Online 
URL:https://nyx.physics.mcgill.ca/event/587/contributions/3629/
END:VEVENT
END:VCALENDAR