Earth and Planetary Astrophysics
Dynamical constraints on planet engulfment as the origin of lithium enhancement in TOI-5882
C. Charalambous, C. Aguilera-Gómez, S. Urrutia et al. (+1 more)
As
stars evolve off the main sequence, changes in
stellar structure can alter the dynamical architecture of planetary systems and, in some cases, lead to
planet engulfment events capable of producing observable chemical signatures such as lithium enhancement. TOI-5882 is a lithium-rich subgiant hosting a 22 m_Jup brown
dwarf on a 7.1-day orbit, where the enrichment could plausibly result from the recent engulfment of a super-Earth to Neptune-mass
planet. We assess the dynamical viability of a
planet engulfment scenario in the TOI-5882 system that could explain its observed Li enrichment. We combine
stellar evolution models with N-body simulations that incorporate time-dependent
stellar properties as the host
star leaves the main sequence, exploring a broad range of pre-engulfment planetary masses and orbital configurations.
Planet engulfment is the most probable outcome under the explored configurations. However, only 5% of the simulations produce engulfment within the short detectability window of the lithium-enrichment signature. Engulfment therefore remains a viable explanation for the observed Li enhancement in TOI-5882, but only for a relatively uncommon subset of the initial conditions considered here. Under our simplified architecture, recent engulfment cannot be ruled out as the origin of the observed lithium enhancement. However, because successful cases represent only a small fraction of the initial conditions explored here, and because additional processes such as wind-induced drag forces were not included, additional constraints on the system's
primordial architecture are needed to assess how likely this scenario is for TOI-5882.
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All authors C. Charalambous, C. Aguilera-Gómez, S. Urrutia, C. Norambuena
Solar and Stellar Astrophysics
Evolution of Non-Stationary Quasi-Periodic Pulsations in Solar Flares with Aditya-L1/HEL1OS and GOES
Srikar Paavan Tadepalli, Abhishekh Kumar Srivastava and K. Sankarasubramanian
In the present work, we use a phase-resolved methodology for the detection and characterisation of non-stationary QPPs in the hard X-ray lightcurves observed from the HEL1OS instrument onboard Aditya-L1 mission, complemented by cross-examination using soft X-ray observations from GOES. Our approach combines variational mode decomposition with
Hilbert-Huang analysis and wavelet transforms to sharpen transient QPP signatures, extract narrowband amplitude-frequency modulated modes, and track instantaneous period drift across various phases of the
flares. By applying these tools to preflare, impulsive, and decay phases and associated intervals, we identify the timing, duration, and
evolution of statistically significant oscillations and assess their relation to thermal and non-thermal
flare components. Finally, we extend the method to the catalogue of non-stationary QPP
flares reported by Mehta et al. (2023), where we identify statistically significant QPPs in both impulsive and decay phases for 74 out of 98
flares. Among these, 56.8% exhibit small period drifts, while 43.2% show larger deviations. Positive period drift dominates (73%), indicating a systematic increase in characteristic timescales as
flares evolve. A phase-period-duration analysis reveals distinct regimes of non-stationarity, including overlapping multi-mode oscillations, intermittent same-period episodes, and strongly evolving multi-modal behaviour.
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Astrophysics of Galaxies
Survival is not Enough: Dust Sputtering, Growth, and H$_2$ Formation in Galactic Winds
Chia-Yu Hu and Max Gronke
A substantial amount of
dust is found in
galactic halos extending far beyond the disks, the origin of which remains an open question. Closely linked and equally puzzling is the detection of molecular gas in high-velocity
galactic winds. To address this, we present the first cloud-crushing simulations that self-consistently include non-
equilibrium cooling and chemistry with
dust growth and sputtering. We find that surviving clouds naturally develop a two-phase structure, with a cold ($\sim 30$ K), dense core embedded in a warm ($\sim 10^4$ K), diffuse envelope. However, the presence of a cold phase does not always lead to molecular winds. While
dust initially in the cloud largely survives in $10^6$ K winds, it is severely depleted by sputtering in hotter winds ($\gtrsim 10^7$ K). Importantly, without
dust growth, the
dust-to-gas ratio (DGR) of the cloud declines rapidly, suppressing the formation of molecular hydrogen (H$_2$) and keeping the entrained cloud atomic, even in cases where the majority of the initial
dust survives. Nonthermal sputtering plays a subdominant role in all cases. The entrained clouds develop high molecular fractions only when
dust growth is enabled, provided the cloud densities are sufficiently high ($\gtrsim$ 10 - 30 times the critical density for cloud survival). Our results suggest that "in situ"
dust growth is essential to explain both the observed abundance of
halo dust and the molecular gas in
galactic winds.
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Astrophysics of Galaxies
BlackTHUNDER Reveals a Massive Filament around a Compact AGN at $z\simeq5.23$
Giulia Tozzi, Hannah Übler, Eleonora Parlanti et al. (+27 more)
Despite the growing number of compact active
galactic nuclei (AGN) at $z>4$ discovered by JWST, their formation and
evolution remain poorly understood. This paper investigates the large-scale environment of GN-77652, a compact AGN at $z=5.229$ observed as part of the JWST NIRSpec IFU Large Program BlackTHUNDER and complemented by deep multi-band NIRCam imaging. GN-77652 lies in close proximity to a 12 kpc-long filament composed of multiple sources at $z\simeq5.23$, spanning a remarkable range in
stellar masses ($M_{\star}=0.7-13 \times 10^8$ ${M_\odot}$), gas phase
metallicities (12$+$log(O/H) $=$ 7.6-8.5) and
star formation rates (SFR $=0.4-6$ ${M_\odot}$ yr$^{-1}$). The [OIII]$\lambda$5007 kinematics reveals a smooth large-scale velocity gradient centred on the central, massive ($M_{\star}\simeq1.1\times10^9$ ${M_\odot}$) and metal rich ($Z\sim0.6$ $Z_{\odot}$) system of the group. In this source, only 2.4 kpc (projected) from GN-77652, [OIII]$\lambda$4363 line diagnostics provide possible evidence for a second AGN. GN-77652 exhibits a shallow ($-30$ to $+20$ km s$^{-1}$) velocity gradient that is consistent with disk rotation according to dynamical modelling. The Lyman-Werner radiation field produced by the filament is too weak for the black hole (BH) in GN-77652 to have formed recently via direct collapse. However, the required conditions may have existed at earlier epochs, or alternative scenarios (e.g. a recoiling BH ejected from the filament) could also be plausible. The whole system is expected to coalesce in $150-440$ Myr, also motivating an exploration of its future
evolution through toy-model extrapolations and numerical simulations. Our analysis suggests that the compact AGN appearance of GN-77652 represents a transient evolutionary phase, consistent with the apparent decline with
redshift in number density of compact AGN identified with JWST.
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All authors Giulia Tozzi, Hannah Übler, Eleonora Parlanti, Roberto Maiolino, Claudia Pulsoni, Rachel Somerville, Mirko Curti, Giovanni Mazzolari, Capucine Barfety, Elena Bertola, Andrew J. Bunker, Stefano Carniani, Giovanni Cresci, Richard Davies, Francesco D'Eugenio, Frank Eisenhauer, Natascha M. Förster Schreiber, Reinhard Genzel, Lucy R. Ivey, Ignas Juodžbalis, Dieter Lutz, Cosimo Marconcini, Thorsten Naab, Meghana Pannikkote, Stavros Pastras, Michele Perna, Letizia Scaloni, Raffaella Schneider, Linda J. Tacconi, Giacomo Venturi
Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc
Degenerate and connection-dependent cosmological sectors in f(Q,C) gravity
Ismael Ayuso
We investigate cosmological solutions in $f(Q,C)$
gravity formulated within symmetric teleparallel geometry, where gravitation is described by the nonmetricity scalar $Q$ and the boundary term $C$, related to the
Ricci scalar of General Relativity through $\mathring{R}=Q+C$ in the absence of
curvature and torsion. The
symmetry requirements of FLRW spacetime admit three distinct realizations of the affine connection, leading in principle to three different cosmological sectors within the same theory. We show that the connection field equations play a crucial role in determining the cosmological dynamics. In their simplest realization, these equations impose a constraint that renders the theory dynamically equivalent to $f(\mathring{R})$
gravity, causing the cosmological background equations associated with the three connection realizations to coincide. This defines a degenerate cosmological sector of $f(Q,C)$
gravity, in which three a priori distinct
geometric constructions converge to the same cosmological dynamics. We then consider the complementary class of genuinely nonequivalent $f(Q,C)$ models, for which the choice of connection becomes physically relevant. In this regime, the connection sector introduces additional dynamical degrees of freedom and gives rise to novel cosmological phenomenology absent in $f(\mathring{R})$
gravity.
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Instrumentation and Methods for Astrophysics
The role of sound and auditory displays in telescope control rooms: a pilot study
Anita Zanella, Sara Lenzi, Sandra Pauletto et al. (+1 more)
Astronomers are often stereotyped as gazing at the
stars. Today, they mainly visually inspect digital data they receive from
telescopes in remote observatories. One of the most complex is the Very Large
Telescope (VLT) in Chile. Multiple streams of information converge in the VLT control room, where
telescopes and instruments are managed, with operators handling numerous tasks on dozens of screens in a challenging environment, marked by harsh geography, intense work rhythms, and isolation. Sound and sonification can represent an efficient novel means for data monitoring with efficiency and operator wellness in mind. We present insights from a qualitative pilot study aimed at assessing the current use of sound in the VLT control room to identify directions for the design of new auditory displays. Based on the analysis of questionnaires and interviews with VLT personnel, we identify the key characteristics of the current use of sound and describe opportunities for improved design strategies to integrate auditory displays in
telescope control rooms to support decision-making, improve situational awareness, and reduce cognitive load.
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All authors Anita Zanella, Sara Lenzi, Sandra Pauletto, Wolfgang Aigner
Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph
Constant Scaling Fails for Global Monopole Networks
Wakutaka Nakano and Wen Yin
Global monopoles, which can also be understood as the zero-gauge-coupling limit of gauged monopoles, can form in the early Universe and evolve following a scaling network, as do other topological defects. However, only a limited number of numerical studies have investigated their scaling behavior. In this Letter, we show that the monopole number density parameter, $\xi$, does not follow the commonly assumed constant scaling. Instead, it exhibits a logarithmic-like
evolution, despite the fact that the energy of an isolated global monopole grows linearly, rather than logarithmically, with the infrared cutoff. This behavior is found using the fat-monopole prescription and is supported by a conventional fixed-core simulation. We characterize the deviation by the fractional response $\gamma\equiv d\log \xi/d\log(m_r/H)$, and find $\gamma\sim 0.5$ for blue-tilted initial spectra. These results suggest that analytic studies based on the assumption of constant scaling should be revisited. They are also relevant to cosmological scenarios involving monopole dark matter,
axion and dark-
photon dark matter produced by monopole networks, monopole-induced
primordial black holes, and gravitational-wave production from monopole dynamics.
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Cosmology and Nongalactic Astrophysics · Cross-listed from nucl-th
Deuterium-Proton Fusion in an Effective Field Theory Constructed from On-Shell Amplitudes
Tim M.P. Tait
Big Bang nucleosynthesis (BBN) predicts the
primordial deuterium abundance to a precision now limited by the
nuclear reactions that burn deuterium. For the simplest of them,
proton-deuteron radiative capture, d + p -> \gamma + 3He [d(p,\gamma)3He], the precise LUNA data sit below the ab initio
benchmark, and BBN reaction networks split on which to adopt. We develop an effective field theory (EFT) expanding in the finite size of the
nuclei, building the amplitude with modern on-shell methods that enumerate every tree-level structure consistent with
symmetries without the need for an explicit Lagrangian. A global
Bayesian fit to the capture data and
nuclear-theory priors returns S(0) = 0.209 +/- 0.008 eV b and traces the offset from the ab initio
benchmark to a single natural-sized next-to-leading contact term (t_E1 ~ -0.15, the fractional shift of the electric-dipole amplitude) – equivalently a ~15% lower effective 3He asymptotic normalization. We estimate the leading EFT truncation errors and identify an elastic d-p observable that would separate them. Our results suggest that amplitude methods enable systematic and complete tree-level construction and matching of EFTs for low-energy
nuclear reactions.
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Cosmology and Nongalactic Astrophysics
Optimal and exact wide-angle power spectrum estimation
Noah Sailer, Kendrick Smith, Yurii Kvasiuk et al. (+2 more)
What is the optimal power spectrum
estimator on ultra-large scales where the plane-parallel approximation breaks down? Conventional
estimators, such as the Yamamoto
estimator, are only optimal in the plane-parallel limit, while their associated window functions are typically approximated by truncating a slowly converging infinite series. We address two outstanding challenges in the analysis of wide-angle power spectra. First, we derive the optimal
estimator for a broad class of clustering signals and show that it is equivalent to a previously proposed two-$\ell$ generalization of the Yamamoto
estimator. Second, we show how to write the exact two-$\ell$ window function as a finite number of terms that can be efficiently evaluated using FFTs. Our results apply to a wide range of observables, including
redshift-space distortions (RSDs) and large-scale radial-velocity reconstruction from the kinetic Sunyaev-Zel'dovich effect. Focusing on linear-theory RSDs, we validate the finite window-function representation numerically and show that the two-$\ell$
estimator can yield order-unity improvements in the signal-to-noise ratio of ultra-large-scale power spectrum measurements.
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All authors Noah Sailer, Kendrick Smith, Yurii Kvasiuk, Alex Laguë, Selim Hotinli
Astrophysics of Galaxies
Constraints on the population level distribution of nearby Dark Matter halo shapes with extragalactic streams
David Chemaly, Elisabeth Sola, Sergey Koposov et al. (+3 more)
Stellar streams trace the gravitational potential of their host
galaxies and provide a sensitive probe of dark matter
halo structure. Previously, we developed, and tested on simulated data, a hierarchical
Bayesian framework to infer the population level distribution of dark matter
halo shapes from ensembles of extragalactic
stellar streams with images only. In this work, we apply this pipeline to 32
stellar streams from the STRRINGS catalogue, a curated sample of dynamically cold minor-merger streams detected in deep imaging. Each stream is forward-modelled assuming an axisymmetric
halo and fitted using only the projected stream track, yielding posterior constraints on the
halo flattening parameter $q$. To account for model mismatch and track systematics, we introduce an additional variance term that inflates the uncertainty on the projected stream track and use it to identify a high quality (gold) subsample of 17 streams whose tracks retain significant constraining power. We then combine the individual posteriors through importance sampling to infer the underlying population distribution of
halo flattening. For the gold subsample, we infer an oblate population with mean $\mu_q \approx 0.72$ and intrinsic scatter $\sigma_q \approx 0.34$. Streams dominated by additional model variance yield a nearly spherical population inference. The inferred oblate population for the gold sample is broadly consistent with expectations from cosmological hydrodynamical simulations. This work provides constraints on dark matter
halo flattening from
stellar streams beyond the Local Group and establishes a scalable framework for forthcoming large samples from Euclid and Rubin/LSST.
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All authors David Chemaly, Elisabeth Sola, Sergey Koposov, HanYuan Zhang, Vasily Belokurov, Denis Erkal
Astrophysics of Galaxies
Globular cluster abundance patterns inherited from giant molecular clouds
William McClymont, Vasily Belokurov, Sandro Tacchella et al. (+16 more)
Globular clusters exhibit large
star-to-
star variations and anticorrelations in their light element abundances that are commonly interpreted in terms of in-cluster self-enrichment, in which ejecta from early-forming cluster
stars pollute the gas from which later
stars form over millions of years. Yet proposed self-enrichment scenarios suffer from a severe mass-budget problem or invoke exotic
stellar populations. Using cosmological radiation-hydrodynamic simulations with a standard chemical enrichment model, we identify a population of
giant molecular clouds whose internal abundance patterns reproduce several key globular cluster signatures: large light-element abundance spreads and nitrogen-oxygen anticorrelations at nearly constant iron abundance. These clouds form at the restart of
star-formation activity after an earlier starburst, where previously ejected oxygen-rich gas collides with nitrogen-rich
galactic gas, and are sites of dense
star-cluster formation. In this picture, the chemical abundance patterns of globular clusters need not require extended in-cluster
star formation, but can be inherited at birth from chemically structured interstellar gas shaped by the
baryon cycle. Globular clusters therefore provide a fossil record of chemical enrichment and gas flows in high-
redshift galaxies.
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All authors William McClymont, Vasily Belokurov, Sandro Tacchella, Rahul Kannan, Aaron Smith, Ewald Puchwein, Enrico Garaldi, Mark Vogelsberger, Stephanie Monty, Josh Borrow, Laura Keating, Xuejian Shen, Zihao Wang, Oliver Zier, Changhyun Cho, Yuki Isobe, Xihan Ji, Roberto Maiolino, Giulia Pruto
High Energy Astrophysical Phenomena
Radiation-hydrodynamics of star-disc collisions: From system parameters to outflows and lightcurves
Taj Jankovič, Sergey Karpov, Michal Zajaček et al. (+2 more)
Quasi-periodic eruptions (QPEs) are
nuclear transients producing bright, repeating soft X-ray
flares superimposed on quiescent emission. A promising interpretation is that they are powered by
star-disc collisions, in which a
star crosses an
accretion disc around a supermassive black hole, drives shocks, and launches dense
outflows from which radiation emerges. We present a systematic study of
star-disc collisions, linking the physical parameters of the collision to the resulting
outflows and emerging bolometric luminosities. We perform three-dimensional local radiation-hydrodynamics simulations, varying the disc surface density and vertical density profiles,
stellar velocity and radius, and local collision angle. We focus on the regime where the
star remains unperturbed by the collision. We find that variations in
stellar velocity and
accretion disc surface density leave the bow shock and
outflow morphology largely unchanged. Faster
stars produce brighter
flares, while denser discs mainly increase the
flare duration. Increasing the
stellar radius increases the momentum of the forward
outflow and produces brighter and longer
flares. More centrally concentrated discs yield brighter and shorter
flares because radiation escapes more efficiently through outer low-density layers. More oblique crossings reduce the momentum and luminosity asymmetry of two
outflows, and lengthen the
flares. We provide empirical scalings of the peak luminosity and
flare duration with the individual system parameters and apply them to GSN 069. The best candidate solutions favour a
star with a radius $\sim R_\odot$ on a retrograde orbit, colliding with a dense post-TDE disc with a vertically concentrated density profile. Our findings suggest that specific combinations of system parameters can reproduce characteristic
flare amplitudes, durations, duty cycles, and strong-weak
flare patterns observed in QPE sources.
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All authors Taj Jankovič, Sergey Karpov, Michal Zajaček, Vladimír Karas, Marzena Śniegowska
Astrophysics of Galaxies
Yiheng Wang, Huiyuan Wang, Enci Wang et al. (+1 more)
A possible origin of disk
galaxy warps is the misalignment between
galactic disks and their host dark matter
halos, the orientations of which are found to be statistically aligned with the large-scale
tidal field. In this work, we test this scenario by examining the
alignment between warped disk
galaxies and the large-scale
tidal field reconstructed from the ELUCID project. We find a statistically significant
alignment signal between disk orientations and the $t_1$ direction, with warped and non-warped
galaxies showing different
alignment behaviors. Warped
galaxies show an excess of intermediate angles and a preference for orientations slightly offset from perfect parallel and perpendicular
alignments. In contrast, non-warped
galaxies exhibit a deficit of intermediate angles relative to random expectations, which becomes more pronounced after matching to a control sample. We also find a clear mass dependence, with high-mass warped
galaxies contributing the excess of intermediate-angle signal. No significant
alignment signal in warped
galaxies is detected with the $t_3$ direction.
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All authors Yiheng Wang, Huiyuan Wang, Enci Wang, Xi Kang
Cosmology and Nongalactic Astrophysics
The dark matter halo mass function in the $\Lambda\mathrm{CDM}$ cosmology at all times and over all scales – from planetary to galaxy cluster masses
Haonan Zheng, Sownak Bose, Carlos S. Frenk et al. (+7 more)
The dark matter
halo mass function is one of the most fundamental predictions of structure formation theory and cosmological simulations. We present the full
halo mass function in the $\Lambda$ cold dark matter ($\Lambda\mathrm{CDM}$) model, ranging from a planetary mass ($10^{-6}\,\mathrm{M}_\odot$; the thermal cutoff in the initial power spectrum for a fiducial CDM particle mass of $100\,\mathrm{GeV}$) to the mass of a rich
galaxy cluster ($10^{15.5}\,\mathrm{M}_\odot$), and from
redshift, $z=30$ to the present. To span this very large dynamic range, we combine our earlier Voids-within-Voids-within-Voids (VVV) set of simulations (Wang et al) with large volume, lower resolution cosmological simulations. We develop a subsampling method to extract subvolumes from the original simulations, allowing us to reconstruct the global
halo mass function from the biased underdense VVV regions. We show that the results agree reasonably well among the sets of simulations on different scales and environments. We provide a fitting formula for the dark matter
halo mass function based on the work of Reed et al. calibrated with our simulations, such that it can be applied at all scales, all environments and all times, with deviations of $\sim2-3\%$ at $z < 2$ and $\sim 7\%$ at higher
redshift $z \gtrsim 5$. This formula is also accurate at least for a restricted set of models we tested with modest deviations from $\Lambda\mathrm{CDM}$ in the values of some of the cosmological parameters. A python code is publicly available at https://github.com/haonan-zheng/hmfc.
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All authors Haonan Zheng, Sownak Bose, Carlos S. Frenk, Liang Gao, Adrian Jenkins, Shihong Liao, Yizhou Liu, Volker Springel, Jie Wang, Simon D. M. White
Cosmology and Nongalactic Astrophysics
A Novel Implementation of Self-Interacting Dark Matter in AREPO
Oliver Zier, Xuejian Shen, Vinh Tran et al. (+3 more)
Self-interacting dark matter (SIDM) influences
halo structure through collisional heat transport and may solve several small-scale puzzles in structure formation. SIDM creates thermalized cores in low-mass
haloes, which may account for the observed cored
dwarf galaxies. During late-time gravothermal core collapse, SIDM can produce dense low-mass DM
haloes and substructures detected through perturbations to cold
stellar streams and strong gravitational lenses. In this work, we present a new Monte-Carlo SIDM implementation in the moving-mesh code AREPO-2, designed for efficiency, scalability, and extensibility. The central feature of the implementation is a dedicated DM-only neighbour-search tree that decouples the scattering solver from
gravity. This preserves compatibility with the hierarchical time integration used by AREPO-2 while leaving the optimized
gravity solver unconstrained. A pairwise communication scheme between MPI tasks allows tracking multiple scattering events in a single timestep while conserving momentum and energy and maintaining parallel consistency by construction. This is complemented by a per-pair timestep criterion that significantly reduces unnecessary timestep restrictions. The implementation natively supports velocity-dependent cross-sections and inelastic interactions, while a compact interface is designed for additional SIDM physics to be implemented without knowledge of the parallelization layer. We validate the implementation for isotropic, elastic scattering using a suite of idealized and cosmological tests. We assess performance and scalability in isolated core-collapse simulations and in cosmological boxes, both DM-only and with
baryons. Except during the late stages of gravothermal collapse, SIDM simulations incur only modest overhead relative to the corresponding CDM runs and are substantially faster than the previous SIDM implementation in AREPO-1.
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All authors Oliver Zier, Xuejian Shen, Vinh Tran, Martin Rosenlyst, Mark Vogelsberger, Rongrong Liu
Astrophysics of Galaxies
The tidal features of the classical Milky Way satellites: Expected in MOND but inconsistent with cold dark matter models
Elena Asencio, Indranil Banik and Pavel Kroupa
Most classical satellites of the Milky Way are known to display signs of
tidal disturbance (e.g.
tidal tails, substructures, and distorted shapes). This cannot be explained by the standard model of cosmology due to its prediction that the dark matter
haloes of the classical satellites confer them with very strong self-
gravity and make them resilient to the Milky Way's gravitational tides. In this work, we estimate the
tidal susceptibility of the classical satellites by comparing their half-mass radius with their theoretical
tidal radius at pericentre in both the standard model and in the Milgromian dynamics (MOND) model. With this approach, we demonstrate that most classical satellites are expected to be tidally perturbed in MOND, so their observed
tidal features are generally in good agreement with MOND expectations. Since gravitational tides can also enhance the velocity dispersion of the satellites, we argue that MOND can plausibly explain the unusually high velocity dispersions reported for some of the classical satellites.
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High Energy Astrophysical Phenomena
Radio and X-ray Observations of the Transitional Supernova 2019yvr: Insights into the Progenitor Mass-Loss History
Raphael Baer-Way, Poonam Chandra, Maryam Modjaz et al. (+7 more)
The final life stages of the massive
star progenitors of stripped-envelope
supernovae (SESNe) are still an open question, especially when it comes to the timing and magnitude of the progenitor stripping. Observing SESNe across the electromagnetic spectrum allows for the most direct constraints on mass loss in the final stages of progenitor
evolution. In this work, we present
radio (GMRT+VLA) and X-ray (Swift+Chandra) observations of SN 2019yvr obtained from 18-1786 days post-explosion. SN 2019yvr was a type Ib
supernova (SN Ib, with strong helium but little or no hydrogen features) that transitioned into a type IIn
supernova (SN IIn, with shock-driven hydrogen features from interaction with circumstellar material (CSM)) at $\sim$ 100 days post-explosion. The
radio evolution is best-fit by a synchrotron self-absorbed model with a $\rho \propto r^{-1.54 \pm 0.31}$ CSM density profile, suggesting a decreasing mass-loss rate from the progenitor in the years leading up to the explosion. The
radio-derived shock speed is high, more than 30,000 km/s at early times, suggesting a compact progenitor
star. The combined
radio and X-ray data probe CSM that extends from $1.7 \times 10^{16}$ cm up to $\sim$ 20$\times10^{16}$ cm and was created by mass loss from $\sim (1-6) \times10^{-5} \rm{M_{\odot} yr^{-1}} $ (assuming a CSM speed of 100 km/s). The combined
dataset rules out any dramatic jump in CSM density (which was seen in the optical analog SN 2014C) associated with the emergence of optical hydrogen emission lines. We place SN 2019yvr in context with similar transitional SNe and discuss implications for the progenitor.
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All authors Raphael Baer-Way, Poonam Chandra, Maryam Modjaz, A.J. Nayana, Keiichi Maeda, Katie Auchettl, Maria R. Drout, Charles D. Kilpatrick, Alak K. Ray, Stuart D. Ryder
Astrophysics of Galaxies
Non-spherical Cows: Introducing the Asphericity Parameter as a Measure of Accretion Geometry
Benjamin A. Seidel, Rhea-Silvia Remus, Lucas C. Kimmig et al. (+2 more)
The outer regions of
galactic halos represent the bridge connecting internal processes within the
galaxy to the larger surrounding
cosmic web. The gas in this bridge region is shaped by the competing processes of cold inflows from the web and hot ejecta from feedback of
supernovae or an active
galactic nucleus. Similarly, the gas around
galaxy clusters characterizes the balance between inflows and
outflows. To study this connection, we introduce a new parameter for quantifying the geometrical configuration of the flow field connecting structures to the
cosmic web, the asphericity parameter. This inflow asphericity is based on a spherical harmonics decomposition of the inflow at the virial boundary of the
halo. It can be computed using both the linear and the logarithmic inflow field. To validate this parameter we apply it to both an extensive toy model set and to simulated
haloes from the Magneticum simulations. We find the linear asphericity to be a tracer of the total power of the non-spherical inflow and the total anisotropy. On the other hand, the logarithmic asphericity traces the covering fraction of inflows at the surface and is highly sensitive to regions with zero inflow (regions that are dominated by
outflow). Thus the asphericity of the flow field is a powerful tool to simultaneously study the geometry of in- and
outflows in numerical simulations.
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All authors Benjamin A. Seidel, Rhea-Silvia Remus, Lucas C. Kimmig, Lucas M. Valenzuela, Klaus Dolag
Earth and Planetary Astrophysics
Puffed-up Edges of Planet-opened Gaps in Protoplanetary Disks. II. The Role of the Planet's Orbital Eccentricity
Jiaqing Bi and Min-Kai Lin
Eccentric
planets constitute a large population of known
exoplanets and may drive significant substructures in protoplanetary disks through
planet-disk interactions if their eccentricities are excited early in the
planet formation process. In this paper, we investigate the impact of a
planet's orbital eccentricity on gas and
dust structures in protoplanetary disks using three-dimensional multifluid hydrodynamic simulations. We find that an eccentric
planet can drive stronger meridional gas circulation around the
planet-opened gap, which significantly enhances the
dust puff-up feature at the gap edge relative to the circular-orbit case. The
planet-induced gap can also become highly leaky to
dust grains when the
planet is eccentric, allowing
dust grains to be transported radially and thereby fill the gap. Furthermore,
dust rings composed of pebble-sized grains are expected to become both larger and radially wider when the
planet is eccentric, with this trend becoming more pronounced at higher
planet eccentricities. Overall, our results suggest that a
planet's orbital eccentricity can play a significant role in shaping gas and
dust structures in protoplanetary disks, with important implications for
planet formation theory and disk observations of the WISPIT 2 system.
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High Energy Astrophysical Phenomena
Formation of rotating supergiants via stellar mergers in dense clusters: Implications for black hole natal spins
Ishaan Satish, Kyle Kremer, Fulya K{\i}roğlu et al. (+2 more)
We investigate how massive
stellar mergers in young
star clusters imprint on black hole
spin distributions and the broader implications for gravitational wave sources. The central hypothesis is that angular momentum transferred during
stellar mergers substantially affects the
spins of the merger products and resulting black holes, with some merger products evolving into collapsar-like objects that retain thick
accretion disks that enable efficient
spin up. This is in contrast to the more general expectation that black holes form with very small
spins, having shed most of their envelope angular momentum via winds and expansion before core collapse. Using roughly 150 N-body models generated with the $\texttt{Cluster Monte Carlo}$ code, $\texttt{CMC}$, we analyze
stellar mergers that lead to black hole formation, prioritizing “significant” events with mass ratio $q>0.1$. After identifying optimal candidates from our $\texttt{CMC}$ models, we explore detailed
stellar structure and post-merger
evolution implications with MESA
stellar evolution models to capture angular momentum injection and pre-collapse profiles most relevant for the BH natal
spin. In our current
dataset representative of Milky Way-like globular clusters, up to roughly half of black holes are formed from such mergers, including up to roughly $10\%$ from significant mergers with $q>0.1$. Preliminary angular momentum estimates indicate substantial
spin-up during the merger, and trends with mass ratio and
stellar properties suggest strong correlations with the final black hole
spin. In some cases, dimensionless
spin parameters of $a\simeq 0.5$ or more are expected. This process has important implications for the dynamical formation and retention of gravitational wave sources in clusters.
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All authors Ishaan Satish, Kyle Kremer, Fulya K{\i}roğlu, Daichi Tsuna, Shahed Shayan Aran
Astrophysics of Galaxies
Uncertainty-Aware Deep Learning for the Ly$\alpha$ Forest: CNN-Based Absorber Detection and Characterization
Paryag Sharma, Vikram Khaire, Ting-Yun Cheng et al. (+2 more)
The Ly$\alpha$ forest is a powerful probe of the intergalactic medium and small-scale matter distribution, but deriving absorber properties traditionally requires computationally expensive Voigt-profile fitting. We present a convolutional neural network (CNN) that identifies and characterizes H I Ly$\alpha$ absorbers directly from
quasar spectra. The model is trained on synthetic spectra generated from the IllustrisTNG simulation and fitted with the VIPER Voigt-profile fitting code to provide training labels. The network simultaneously predicts absorber presence, column density ($N_{\rm HI}$), Doppler parameter ($b_{\rm HI}$), and line centroid. On simulated spectra, the CNN achieves an F1 score of $\sim$0.8, with mean absolute errors of $\sim$0.18 in $\log N_{\rm HI}$ and $\sim$0.10 in $\log b_{\rm HI}$. It accurately reproduces the H I column density distribution function (CDDF) and the $b_{\rm HI}$–$N_{\rm HI}$ relation, recovering CDDF slopes consistent with VIPER and a lower-envelope relation with an RMS difference of only 0.36 km s$^{-1}$. Applied to high-resolution UVES spectra, performance decreases to an F1 score of $\sim$0.5, with mean absolute errors of $\sim$0.34 in $\log N_{\rm HI}$ and $\sim$0.21 in $\log b_{\rm HI}$. Latent-space analysis reveals a significant domain shift between the simulated and observational spectra, contributing to the reduced performance. Nevertheless, the CNN preserves the observed CDDF and $b_{\rm HI}$–$N_{\rm HI}$ distributions, yielding CDDF slopes consistent with VIPER and a lower-envelope RMS difference of 2.96 km s$^{-1}$. Monte Carlo dropout is implemented during inference to quantify predictive uncertainties. Together with its computational efficiency, the method provides a scalable and uncertainty-aware framework for Ly$\alpha$ forest analysis in upcoming spectroscopic surveys.
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All authors Paryag Sharma, Vikram Khaire, Ting-Yun Cheng, Hum Chand, Prakash Gaikwad
Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc
Three-dimensional wave optics for weak-field lensing of gravitational waves
Mariana Carrillo-González, Alan Heavens and Lorne Whiteway
We develop a perturbative Green's function approach to gravitational
lensing by weak gravitational potentials that need not be localized on a thin lens plane and that applies in both the wave optics and
geometric optics regimes. We recast position-space integrals as
Fourier, or momentum-space, integrals that appear in scattering amplitude calculations. The method gives the Born approximation directly in three dimensions and can be systematically extended to post-Born orders. For a Schwarzschild lens, we compute the leading Born term and new post-Born contributions arising from the order $\mathcal{O}(G^2)$ correction to the potential, keeping finite-distance corrections beyond the usual paraxial expansion. We show that these general-relativistic corrections are controlled by the parameter $GM\omega\,b/\chi_{\rm eff}$ in the small-angle regime, and are therefore negligible for standard weak-
lensing configurations but become relevant in more extreme geometries (such as hierarchical triples with very small source–lens separations). We also discuss higher-order Newtonian corrections, their infrared sensitivity for a long-range potential, and the regulated form of the Newtonian potential given by the Yukawa potential. Finally, we formulate the corresponding calculation in an FLRW background, identifying the leading flat-space limit and estimating the size of
curvature-induced corrections including tails. This method clarifies the regime of validity of the Born, large-distance, and paraxial approximations in gravitational-wave
lensing and provides a framework for treating generic
lensing potentials.
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Cosmology and Nongalactic Astrophysics · Cross-listed from hep-th
The Fate of Black Hole-Induced Moduli Excursions in the Presence of Scalar Potentials
Karim Benakli and Anna Chrysostomou
Large charged black holes can create macroscopic, locally weakly curved regions in which
moduli take values different from their asymptotic values. We study how robust this mechanism is once the scalar has a nontrivial potential. In four-dimensional Einstein-Maxwell-dilaton theory, the massless GHS solution provides a finite exterior throat in which the scalar and the gauge coupling vary logarithmically. We develop fixed-throat diagnostics for the competition between the black hole gauge source and a scalar potential, and compare them with back-reacted exterior evolutions when needed. The relevant criterion is not the mere presence of a potential, but how its force behaves along the scalar trajectory traced by the black hole throat. Quadratic stabilizing potentials erase the throat when the Compton wavelength becomes comparable to the horizon scale. Runaway, periodic, and barrier-type potentials instead exhibit distinct failure modes controlled by their slope, sign, oscillations, or barrier distance along the GHS trajectory. A quintessence-like scalar remains effectively massless on astrophysical black hole scales, leaving the throat essentially unobstructed. If the charge belongs to a hidden sector, and if the scalar also controls visible couplings or bulk propagation, such surviving altered-modulus regions could leave phenomenological imprints in near-horizon
accretion or emission.
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High Energy Astrophysical Phenomena · Cross-listed from gr-qc
Finite signal-to-noise ratio bias in parameter estimation for damped oscillations: cautionary remark about catalog-level black-hole spectroscopy
Koutarou Kyutoku
We investigate biases in parameter estimation for damped oscillations motivated by applications to black-hole spectroscopy in gravitational-wave physics. Focusing on the simplest model of a single-mode damped sinusoid with a fixed start time in white noise, we show that, at finite signal-to-noise ratio \rho, the damping time is biased toward larger values without being suppressed by the quality factor for two reasons. One is the gradient of the prior, through which the damping time is affected by the typically decreasing prior on the amplitude. The other is a higher-order finite-\rho correction to the likelihood geometry. These biases arise even if the model and analysis are appropriate. Moreover, they could be exaggerated in naive joint inferences from catalog events. Quantitatively, if estimates from multiple events with \rho=10 are combined without due care, the catalog-level black-hole spectroscopy could report false violation of the Kerr hypothesis with >~100 events. We also propose simple strategies to mitigate these biases at the level of individual events.
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Instrumentation and Methods for Astrophysics
The Impact of Space Debris on Optical Astronomy
Anthony Mallama, Sergey Karpov and Richard E. Cole
Photometric observations of space debris objects brighter than magnitudes 6.0, 7.0 and 8.0 are characterized. Those magnitudes pertain to different levels of interference with astronomy as defined by the International Astronomical Union. The densities of debris objects per square degree of sky and brighter than the magnitudes listed above are only 6, 13 and 24 parts per million, respectively. Furthermore, only about 1.4%, 2.5% and 3.8% of the 12,173 debris objects cataloged by NORAD exceed those magnitudes for even a small fraction of the time. So, debris trails have a minor impact on astronomical images and visual sightings are few. Characteristics of debris resulting from selected spacecraft collisions and rocket explosions are also quantified. This study is based on 13 million observations recorded by the MMT9 observatory.
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Instrumentation and Methods for Astrophysics
Interpretable Human-Label-Free Deep Learning for Real-Bogus Classification with Uncertainty Quantification
Raphaël Bonnet-Guerrini, Bruno Sanchez, Dominique Fouchez et al. (+5 more)
Time-domain surveys generate many transient candidates, making Real-Bogus classification a critical step in automated discovery pipelines. Reliable labels are costly, while community labels can be noisy and survey-dependent. We aim to develop a Real-Bogus classification framework that can be trained without human-labeled data using injected transients and bogus-dominated survey data, remains robust under strong class contamination, and provides calibrated uncertainty quantification. We combine simulated transient injections with a contaminated survey class and train a dual-network model using asymmetric co-teaching for classes with different label-noise levels. We evaluate performance on a
benchmark subset and analyze the learned representation with latent-space visualization tools. For uncertainty quantification (UQ), we compare MC dropout and deep ensembles and propose a low-cost hybrid strategy that exploits the dual-network setting to improve calibration. We extend the evaluation to the light-curve domain to assess recovery of light-curve classes. The method achieves strong Real-Bogus performance on the labeled subset and remains stable under severe class contamination. It recovers transient light-curve classes with high fidelity, while single-source identification is limited by ambiguity in light-curve-derived labels. Our hybrid UQ approach achieves competitive calibration relative to more expensive ensemble baselines. Latent-space analyses indicate that uncertainty aligns with the decision boundary and reveal subclasses within the bogus population. Our results show that injection-driven, weakly supervised training can enable scalable and consistent Real-Bogus classification without human-labeled training data while providing calibrated uncertainties. The method is suited for transfer to forthcoming surveys by re-running the injection-based training pipeline.
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All authors Raphaël Bonnet-Guerrini, Bruno Sanchez, Dominique Fouchez, Benjamin Racine, Maya Guy, Mariam Sabalbal, Manal Yassine, Vincenzo Piuri
Cosmology and Nongalactic Astrophysics
Effects of Solar Wind Plasma Noise on Stochastic Gravitational Wave Background Searches with the LISA-Taiji Network
Mengfei Sun, Borui Wang, Jie Wu et al. (+2 more)
The LISA-Taiji dual detector network improves millihertz SGWB sensitivity through cross correlation measurements.
Solar wind
plasma, however, can generate
plasma noise correlated between detectors and bias SGWB cross correlation estimates. We use high time resolution electron density data from Wind/SWE, estimate the
solar wind electron density fluctuation spectrum with the Lomb-Scargle method, and propagate the resulting
plasma noise to the TDI A/E channels of the LISA-Taiji network. By including finite arm propagation, Taylor frozen flow spatial correlations, and the network overlap reduction response, we compute the SGWB parameter bias induced by interdetector
plasma noise. Although the single detector
plasma residual is below the reference noise, the component correlated between detectors can enter the SGWB cross correlation
estimator directly. Under dual detector scale coverage, the
plasma induced parameter bias for a power law SGWB can reach 12.73% of the corresponding Fisher parameter uncertainty. For M2/M3
cosmic string spectra, the bias in ln Gmu can reach 19.26% of the corresponding Fisher parameter uncertainty for the network configurations, observing times, and frequency bands considered here. These results show that the impact of
solar wind
plasma noise cannot be assessed from the single detector residual noise level alone. In LISA-Taiji SGWB searches, the interdetector correlated component of this noise can directly affect parameter estimation.
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All authors Mengfei Sun, Borui Wang, Jie Wu, Jin Li, Shengyi Ye
Cosmology and Nongalactic Astrophysics
Investigating a Possible Variation of the Gravitational Constant Through Gas Mass Fraction Measurements and Type Ia Supernovae Observations
L. R. Colaço, R. F. L. Holanda and Marcelo Ferreira
In this paper, we investigate a possible time variation of the gravitational constant (G) using a non-parametric approach. Our main cosmological probe is the gas mass fraction of
galaxy clusters measured from X-ray observations. We also account for the effect of a varying $G$ on the intrinsic luminosity of type Ia
supernovae (SNe Ia) through the Chandrasekhar mass-luminosity relation. We consider a specific phenomenological scenario, motivated by some scalar-tensor and screened modified-
gravity frameworks, in which the standardized luminosity of SNe Ia decreases with increasing Chandrasekhar mass. Using gas mass fraction measurements jointly with luminosity distances from the Pantheon+ compilation, we reconstruct the
evolution of G through Gaussian Processes. Our results indicate that a constant gravitational coupling remains broadly consistent with the data, although mild low-
redshift departures are allowed.
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Instrumentation and Methods for Astrophysics
Characterizing Photonic Ring Resonator Filters for OH Suppressed Near-infrared Astronomy
A. Hermann, J. Lasker, R. Vaisakh et al. (+6 more)
Supernova cosmology relies on accurate measurement of the absolute magnitudes of Type Ia
supernovae. Observation in the visible incurs significant systematic uncertainties in these measurements due to their high degree of interstellar
dust extinction. Observing in the near-infrared (750-2500 nm) mitigates this issue by decreasing attenuation, decreasing dispersion, and increasing
supernova observation distances. However, ground-based observations in the near-infrared suffer from sky background caused by atmospheric OH emission lines. Advancements in photonic ring resonator filter devices make it feasible to suppress these lines. In this paper, we evaluate the performance of a prototype photonic ring resonator device developed for use in the lower H-band (1480-1620 nm). Specifically, we characterize the progression of suppressed wavelengths into the upper H-band (1620-1800 nm) enabling the suppression of emission lines over a broader wavelength range.
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All authors A. Hermann, J. Lasker, R. Vaisakh, R. Kehoe, R. Staten, A. Wallace, S. Ellis, K. Kuehn, S. Kuhlmann
High Energy Astrophysical Phenomena · Cross-listed from hep-ph
Jorge Terol Calvo, Pedro de la Torre Luque, Mainak Mukhopadhyay et al. (+2 more)
The IceCube and ANTARES collaborations have recently reported evidence for high-energy
neutrinos associated with the
Galactic plane and the
Galactic Ridge, offering a new pathway to search for dark matter (DM). Deep inelastic scattering of
cosmic rays with sub-GeV DM in the
Galactic halo produces a distinctive
neutrino signature from
meson decays. Using detailed
Galactic cosmic-ray maps and ANTARES observations, we derive 99% C.L. upper limits on the DM-nucleon cross section that extend down to keV-scale masses. These results establish
Galactic neutrino telescopes as a powerful, complementary probe of light DM, with substantial improvements expected from upcoming IceCube-Gen2 and KM3NeT observations.
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All authors Jorge Terol Calvo, Pedro de la Torre Luque, Mainak Mukhopadhyay, Chris Cappiello, Gonzalo Herrera