Instrumentation and Methods for Astrophysics · Cross-listed from gr-qc
Microseismic Noise Mitigation with Machine Learning for Advanced LIGO
Christina Reissel, Devin Lai, Shivanshu Dwivedi et al. (+9 more)
The unprecedented sensitivity of the
Laser Interferometer Gravitational-Wave Observatory, which enables the detection of distant astrophysical sources, also renders the detectors highly susceptible to low-frequency ground motion. Persistent microseisms in the 0.1-0.3 Hz band couple into the instruments, degrade lock stability, and contribute substantially to detector downtime during observing runs. The multi-stage seismic isolation system has achieved remarkable success in mitigating such disturbances through active feedback control, yet residual platform motion remains a key factor limiting low-frequency sensitivity and duty cycle. Further reduction of this residual motion is therefore critical for improving the long-term stability and overall astrophysical reach of the observatories. In this work, we develop a data-driven approach that uses machine learning to model and suppress residual seismic motion within the isolation system. Ground and platform sensor data from the detectors are used to train a neural network that predicts platform motion driven by microseismic activity. When incorporated into the control scheme, the network's predictions yield up to an order-of-magnitude reduction in residual motion compared to conventional linear filtering methods, revealing that nonlinear couplings play a significant role in limiting current isolation performance. These results demonstrate that machine-learning-based control can provide a powerful new pathway for enhancing active seismic isolation, improving lock robustness, and extending the low-frequency observational capabilities of gravitational-wave detectors.
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All authors Christina Reissel, Devin Lai, Shivanshu Dwivedi, Edgard Bonilla, Claudia Geer, Christopher Wipf, Richard Mittleman, Philip Harris, Eyal Schwartz, Dovi Poznanski, Brian Lantz, Erik Katsavounidis
High Energy Astrophysical Phenomena
Optical and cm follow-ups of the Changing-Look event in Mkn 590
Biswaraj Palit, Abhijeet Borkar, Agata Różańska et al. (+5 more)
The Changing-Look active
galactic nucleus Mkn 590 is currently in a rejuvenated state, exhibiting a contemporaneous flux rise across X-rays, UV, optical and cm wavelengths. In this study, we present three new optical spectra obtained with the Nordic Optical
Telescope, alongside three 1.4 GHz continuum measurements from the
Giant Meterwave
Radio Telescope, acquired since Nov. 2024. We identified a clear increase in the broad hydrogen Balmer line emission in the most recent observational epochs. Additionally, the core
radio flux densities appear to track the overall X-ray variability, suggesting a possible connection between the
accretion flow and jet activity. Based on these data, we aim to explore the
evolution of the circumnuclear gas in this source and potential links between
accretion and ejection activity.
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All authors Biswaraj Palit, Abhijeet Borkar, Agata Różańska, Alex Markowitz, Marzena Śniegowska, Swayamtrupta Panda, David Homan, Krystian Iłkiewicz
Astrophysics of Galaxies
Tracing ionized gas kinematics in Lyman-Break Analogs. Implications for star formation compactness and outflow properties
Ana León Contreras, Ricardo Amorín, Mario Llerena et al. (+1 more)
We present a study of the ionized gas kinematics and feedback properties in a sample of 14 low-mass, UV-luminous Lyman Break Analogs (LBAs) at
redshifts z~0.1-0.3. These compact, strongly
star-forming
galaxies serve as local analogs of high-
redshift starbursts. Using high-resolution VLT/X-shooter spectra, we model the optical emission-line profiles, including [O III] 4959,5007 and the Balmer lines, with multi-component Gaussian fits. All
galaxies show complex kinematics that require both narrow (sigma < 90 km/s) and broad (sigma > 90 km/s) components. The narrow components trace highly turbulent gas associated with massive
star-forming regions, while the broad components indicate ionized
outflows driven by
stellar winds and
supernova feedback, with
outflow velocities of about 200-500 km/s. Estimated mass
outflow rates range from 0.20 to 2.72
solar masses per year, with mass-loading factors between 0.03 and 0.81. We find a mild increase in mass loading toward lower
stellar masses, as well as a strong correlation between mass loading and
star-formation-rate surface density, suggesting that more compact starbursts drive more powerful
outflows. These trends are consistent with those seen in
star-forming
galaxies at higher
redshifts. Our results highlight the importance of local UV-compact starbursts for understanding feedback processes in low-mass, rapidly
star-forming
galaxies.
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All authors Ana León Contreras, Ricardo Amorín, Mario Llerena, Vital Fernández
Earth and Planetary Astrophysics
Planetary Habitability Under the Light of a Rapidly Changing Star
Tara Fetherolf, Sadie G. Welter, Colby M. Ostberg et al. (+3 more)
Planetary atmospheric energy budgets primarily depend on
stellar incident flux. However,
stellar variability can have major consequences for the
evolution of planetary climates. In this work, we evaluate how
stellar variability influences the
equilibrium temperature and water retention of
planets within the Habitable Zone (HZ). We present a sample of 9
stars that are known to host at least one
planet within the HZ and that were identified to have a variability amplitude exceeding 100 ppm based on photometry from the Transiting
Exoplanet Survey Satellite (TESS). We investigate the effect that the variability of these
stars have on the insolation flux of their HZ
planets and the resulting changes in the induced planetary
equilibrium temperature. Our results show that for the
stars in our sample, the
stellar variability has an insignificant effect on the
equilibrium temperature of HZ
planets. However, we also emphasize that these
stars are not representative of more extreme variable
stars, since
exoplanets are more difficult to detect and characterize in the presence of extreme variability. We also investigate the
equilibrium temperature and long-term
evolution of a hypothetical Earth-like
planet placed at the inner edge of the HZ around a highly variable
star. We found that the water loss rates are comparable between both variable and quiet host
stars for Earth-like
planets in the inner HZ. Overall, these results broaden our knowledge on the impact of
stellar variability on planetary habitability.
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All authors Tara Fetherolf, Sadie G. Welter, Colby M. Ostberg, Stephen R. Kane, Rory Barnes, Emilie R. Simpson
Astrophysics of Galaxies
Disc growth and vertical heating of lenticular galaxies in the Fornax cluster
Marie Martig, Francesca Pinna, Jesús Falcón-Barroso et al. (+3 more)
We present a detailed analysis of the vertical and radial structure of mono-age
stellar populations in three edge-on lenticular
galaxies (FCC 153, FCC 170, and FCC 177) in the Fornax cluster, using deep MUSE observations. By measuring the half-mass radius (R$_{50}$) and half-mass height (z$_{50}$) across 1 Gyr-wide age bins, we trace the spatial
evolution of
stellar populations over
cosmic time. All
galaxies exhibit a remarkably constant disc thickness for all
stars younger than ~6 Gyr, suggesting minimal secular heating and limited impact from environmental processes such as
tidal shocking or harassment. Evidence of past mergers (8-10 Gyr ago) is found in the increase of z$_{50}$ for older populations. We find that accreted (metal-poor)
stars have been deposited in quite thick configurations, but that the interactions only moderately thickened pre-existing
stars in the
galaxies, and only caused mild flaring in the outer regions of the discs. The radial structure of the discs varies across
galaxies, but in all cases we find that the radial extent of mono-age populations remains constant or grows over the past 8 Gyr. This leads us to argue that within the radial range we consider, strangulation, rather than ram-pressure stripping, is the dominant quenching mechanism in those
galaxies. Our results highlight the usefulness of analysing the structure of mono-age population to uncover the mechanisms driving
galaxy evolution, and we anticipate broader insights from the GECKOS survey, studying 36 nearby edge-on disc
galaxies.
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All authors Marie Martig, Francesca Pinna, Jesús Falcón-Barroso, Ignacio Martín-Navarro, Ivan Minchev, Yuchen Ding
Astrophysics of Galaxies
Metal-loaded outflows in sub-Milky Way galaxies in the CIELO simulations
Valentina P. Miranda, Patricia B. Tissera, Emanuel Sillero et al. (+5 more)
Supernova (SN) feedback-driven
galactic outflows are a key physical process that contributes to the
baryon cycle by regulating the
star formation activity, reducing the amount of metals in low-mass
galaxies and enriching the circumgalactic (CGM) and intergalactic media (IGM). We aim to understand the chemical loop of sub-Milky Way (MW)
galaxies and their nearby regions. We studied 15 simulated central sub-MW
galaxies (M* <= 10^10 Msun) and intermediate-mass
galaxies (M* \sim 10^10 Msun) from the CIELO-P7 high-resolution simulations. We followed the
evolution of the progenitor
galaxies, their properties and the characteristics of the
outflows within the
redshift range z = [0, 7]. We used two dynamically-motivated
outflow definitions, unbound
outflows and expelled mass rates, to quantify the impact of SN feedback. At z \sim 0, sub-MW
galaxies have a larger fraction of their current oxygen mass in the gas phase but have expelled a greater portion beyond the virial radius, compared to their higher-mass counterparts.
Galaxies with M* <\sim 10^9 Msun have 10-40 per cent of their total oxygen mass within R200 in the CGM, and an equivalent to 10-60 per cent expelled into the IGM. In contrast, more massive
galaxies have most of the oxygen mass locked by the
stellar populations. The CGM of low-mass
galaxies predominantly contains oxygen low-temperature gas, acting as a metal reservoir. We find that the
outflows are more oxygen-rich for sub-MW
galaxies, Zout/ZISM \sim 1.5, than for higher-mass
galaxies, Zout/ZISM <= 0.5, particularly for z < 2. Mass-loading factors of eta_out \sim 0 - 6 are detected in agreement with observations (abridged).
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All authors Valentina P. Miranda, Patricia B. Tissera, Emanuel Sillero, Jenny Gonzalez-Jara, Lucas Bignone, Ignacio Muñoz-Escobar, Susana Pedrosa, Rosa Domínguez-Tenreiro
Astrophysics of Galaxies
SE3D: Building a radiative transfer emulator to fit panchromatic resolved galaxy observations with 3D models of dust and stars
Steven Ramnichal, Junkai Zhang, Stijn Wuyts et al. (+1 more)
We present a framework for analysing panchromatic and spatially resolved
galaxy observations, dubbed SE3D. SE3D simultaneously and self-consistently models a
galaxy's spectral energy distribution and its spectral distributions of global structural parameters: the wavelength-dependent
galaxy size, light profile and projected axis ratio. To this end, it employs a machine learning emulator trained on a large library of toy model
galaxies processed with 3D
dust radiative transfer and mock-observed under a range of viewing angles. The toy models vary in their
stellar and
dust geometries, and include radial
stellar population gradients. The computationally efficient machine learning emulator uses a
Bayesian neural network architecture, and reproduces the spectral distributions at an accuracy of ~ 0.05 dex or less across the dynamic range of input parameters, and across the rest-frame UVJ colour space spanned by observed
galaxies. We carry out a sensitivity analysis demonstrating that the emulator has successfully learned the intricate mappings between
galaxy physical properties and direct observables (fluxes, colours, sizes, size ratios between different wavebands, ...). We further discuss the physical conditions giving rise to a range of total-to-selective attenuation ratios, Rv, with among them most prominently the projected
dust surface mass density.
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All authors Steven Ramnichal, Junkai Zhang, Stijn Wuyts, Cheng Li
High Energy Astrophysical Phenomena · Cross-listed from hep-ph
Two Puzzles, One Solution: Neutrino Mass and Secluded Dark Matter
Mattia Di Mauro
We present a minimal secluded dark-matter (DM) framework based on an extra $U(1)_X$ gauge
symmetry. The model contains a Dirac DM particle $\chi$, three heavy
neutrinos $N_I$ with masses $M_{N,I}$, and a singlet scalar $R$ that mixes with the Standard Model
Higgs doublet $\Phi$ by an angle $\alpha$. A
symmetry forbids the $\Phi$-$R$ portal at tree level; the leading portal then arises at one loop from the same Yukawa structures that generate active
neutrino masses $m_{\nu,I}$, implying $\tan(2\alpha) \propto \sum_I m_{\nu,I} M^2_{N,I}/(v_h m_H^2)$, where $v_h$ and $m_H$ are the SM
Higgs VEV and mass. For heavy-
neutrino masses in the multi-TeV range, this yields a naturally tiny mixing, $\tan(2\alpha)\sim 5\times 10^{-11}\left(M_N/10~\mathrm{TeV}\right)^2$, which strongly suppresses DM signals in direct, indirect, and
collider searches. For PeV-scale heavy
neutrinos the DM-nucleon cross section can instead enter the reach of direct-detection experiments. The visible and dark sectors thermalize at temperatures of order a few times the mass of the lightest heavy
neutrino, then subsequently decouple, and typically evolve with a slightly hotter dark bath. In the secluded regime, with $\tan(2\alpha)\ll 1$ and $m_\chi>m_{H_p}$, the relic density is set by $p$-wave annihilation $\chi\bar\chi \to H_p H_p$ (with $H_p$ the
Higgs-like particle of the dark sector), and the dark-sector Yukawa couplings required to reproduce the observed abundance are $\sim(0.1\text{-}1)$, as in the standard WIMP case. For heavy-
neutrino masses $\gtrsim 10~\mathrm{TeV}$, the mediator decays before nucleosynthesis without spoiling BBN observables, while the tiny portal suppresses present-day signals below current and near-future sensitivities. This links two long-standing puzzles, the absence of DM signals and the smallness of
neutrino masses, within a predictive thermal framework.
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Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph
Probing High Reheating Temperatures by Direct Detection Experiments
Barmak Shams Es Haghi
We argue that the
benchmark freeze in dark matter (DM) scenario for direct detection experiments, in which a DM candidate interacts with the Standard Model (SM) through an ultralight dark
photon, becomes sensitive to the visible sector reheating temperature if it is sufficiently high. At such temperatures, the irreducible ultraviolet (UV) freeze in production of DM through graviton exchange becomes important and must be combined with the infrared (IR) freeze in yield mediated by the dark
photon. As long as gravitationally produced DM does not equilibrate through annihilation into dark
photons and the subsequent formation of a dark thermal bath, it retains information about the reheating phase. Including this gravitational contribution relaxes the required DM and SM portal coupling and allows smaller values than those that would match the observed relic abundance through IR freeze in alone. Since current direct detection experiments have excluded the
benchmark freeze in model over a wide range of DM masses, they are now effectively probing high reheating temperatures and the gravitational freeze in of DM.
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Cosmology and Nongalactic Astrophysics
Detection of the Cosmological 21 cm Signal in Auto-correlation at z ~ 1 with the Canadian Hydrogen Intensity Mapping Experiment
CHIME Collaboration, Mandana Amiri, Kevin Bandura et al. (+36 more)
We present the first detection of the cosmological 21 cm intensity mapping signal in auto-correlation at z ~ 1 with the Canadian Hydrogen Intensity Mapping Experiment (CHIME). Using 94 nights of observation, we have measured the 21 cm auto-power spectrum over a frequency range from 608.2 MHz to 707.8 MHz (z = 1.34 to 1.01) at 0.4 h Mpc^-1 < k < 1.5 h Mpc^-1, with a detection significance of 12.5 sigma. Our analysis employs significant improvements to the CHIME data processing pipeline compared to previous work, including novel
radio frequency interference (RFI) detection and masking
algorithms, achromatic beamforming techniques, and foreground filtering before time averaging to minimize spectral leakage. We establish the robustness and reliability of our detection through a comprehensive suite of validation tests. We also measure the 21 cm signal in two independent sub-bands centered at z ~ 1.08 and z ~ 1.24 with detection significance of 8.7 sigma and 9.2 sigma, respectively. We briefly discuss the theoretical interpretation of these measurements in terms of a power spectrum model, deferring the details to a companion paper. This auto-power spectrum detection demonstrates CHIME's capability to probe large-scale structure through 21 cm intensity mapping without reliance on external
galaxy surveys.
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All authors CHIME Collaboration, Mandana Amiri, Kevin Bandura, Arnab Chakraborty, Jean-François Cliche, Matt Dobbs, Simon Foreman, Liam Gray, Mark Halpern, Alex S Hill, Gary Hinshaw, Carolin Höfer, Albin Joseph, Nolan Kruger, T.L. Landecker, Rik van Lieshout, Joshua MacEachern, Kiyoshi W. Masui, Juan Mena-Parra, Kyle Miller, Nikola Milutinovic, Arash Mirhosseini, Laura Newburgh, Anna Ordog, Ue-Li Pen, Tristan Pinsonneault-Marotte, Alex Reda, Andre Renard, Kana Sakaguri, J. Richard Shaw, Shabbir Shaikh, Seth R. Siegel, Saurabh Singh, David Spear, Yukari Uchibori, Keith Vanderlinde, Haochen Wang, Donald V. Wiebe, Dallas Wulf
Cosmology and Nongalactic Astrophysics
Improving divergence cleaning in cosmological SPMHD simulations
Ulrich P. Steinwandel and Daniel J. Price
We implement the constrained
hyperbolic/
parabolic divergence cleaning
algorithm into the cosmological smoothed particle magnetohydrodynamics (SPMHD) code OpenGadget3, modifying the governing equations so that the scheme can be applied consistently in an expanding cosmological framework. This ensures that divergence errors in the
magnetic field are actively propagated away and damped, rather than advected with the flow and partially controlled by source terms as in the previously employed Powell eight-wave approach. We validate the implementation on a series of standard test problems – the advection of an artificial divergence pulse, the Orszag–Tang
vortex, the Brio–Wu shock tube, and a magnetised Zeldovich pancake – which confirm that the scheme reduces divergence errors while preserving the correct physical
evolution. We then apply the method to a fully cosmological simulation of a massive
galaxy cluster with $M_\mathrm{200c} \approx 10^{15}~\mathrm{M}_{\odot}$, and compare directly to the Powell-only approach. The overall density structure of the cluster is largely unchanged by the choice of divergence cleaning, and the
magnetic field geometry and strength in the cluster core remain similar. In the cluster outskirts ($r \approx 1$–$3~h^{-1}$~Mpc), however, the
magnetic field is amplified by a factor of 5–10 compared to the Powell-only run, while the divergence error is reduced by 2–3 orders of magnitude throughout the cluster volume. Our results suggest that accurate divergence control is essential for capturing
magnetic field amplification in the low-density, poorly resolved outskirts of
galaxy clusters.
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Astrophysics of Galaxies
SE3D: Testing the recovery of stellar population, dust and structural properties on mock-observed toy model and simulated galaxies
Junkai Zhang, Steven Ramnichal, Stijn Wuyts et al. (+1 more)
The translation from direct observables to physical properties of
galaxies is a key step in reconstructing their evolutionary histories.
Star-
dust geometry and inhomogeneous
stellar populations can induce spatial variations in the mass-to-light ratio, complicating this process. In this paper, we present tests of SE3D, a novel modelling framework built around a radiative transfer emulator, aimed at tackling this problem. We test the ability to recover known intrinsic properties of toy model and TNG50 simulated
galaxies by jointly fitting mock observations of their multi-wavelength photometric and structural properties. We find an encouraging performance ($\lesssim$ 0.1 dex) for several key characteristics, including the bulk
stellar mass,
dust mass and SFR, as well as their respective radial extents. We point out limitations, and investigate the impact of various sources of model mismatch. Among them, mismatch in the shapes of
star formation histories contributes most, with radial and azimuthal structure and
stellar metallicity distributions playing a progressively more minor role. We also analyse the
evolution from z=2 to z=0 of resolved
stellar and
dust properties of TNG
galaxies, as measured intrinsically and expressed in their distribution across UVJ and IRX-$\beta$ diagnostic diagrams. We test different methods to assign
dust to the simulation, and find a persistent lack of Mdust/Mstar
evolution and a more limited dynamic range across the diagnostic diagrams compared to observations.
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All authors Junkai Zhang, Steven Ramnichal, Stijn Wuyts, Cheng Li
High Energy Astrophysical Phenomena · Cross-listed from gr-qc
Effective-one-body modelling of eccentric supermassive black hole binaries for Pulsar Timing Array
Sara Manzini and Stanislav Babak
Pulsar Timing Arrays (PTAs) observations will detect gravitational waves (GWs) from the early inspiral phase of supermassive black hole binaries (SMBHBs) with orbital periods of weeks to years. Current PTA analyses generally assume circular binaries; however, dynamical interactions with the surrounding environment can prevent complete circularisation, allowing SMBHBs to retain appreciable eccentricities. In this work, we present a gravitational waveform model for eccentric binaries based on the Effective-One-Body (EOB) formalism, designed for continuous GW searches in PTA data. The model is accurate up to the second post-Newtonian (2PN) order for the conservative dynamics and up to post-leading order for the radiation-reaction terms. We provide both a numerically precise and a computationally efficient approximate implementation and evaluate the latter's accuracy against the full model over a broad range of eccentricities and initial orbital frequencies. Our results show that a substantial region of the parameter space exhibits pronounced orbital
evolution, much stronger than in the circular case. We demonstrate the rich harmonic structure of timing residuals induced by eccentric GWs. Properly characterising eccentric binaries is an essential step toward detecting GWs in PTA data and interpreting the results, ultimately improving our understanding of the supermassive black hole population in the local Universe.
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Cosmology and Nongalactic Astrophysics · Cross-listed from hep-th
Effect of Moduli Redefinitions on Fibre Inflation
Dibya Chakraborty, Mishaal Hai, Sayeda Tashnuba Jahan et al. (+2 more)
In this paper, we have discovered a new avenue of fibre inflation in perturbative large volume scenario (pLVS) due to the redefinition of the base modulus. pLVS offers a novel regime where large volume of the internal space is guaranteed without the need of non-perturbative effects. In this setup, we study the possibility where a base redefinition allows to assess different versions of fibre inflation whose spectral index aligns with Atacama Cosmology
Telescope (ACT) data and produces tensor-to-scalar ratio in the range $0.008\lesssim r\lesssim 0.01$ in different setups we have considered. The leading order flat direction - which in our case is the fibre modulus - is lifted with the combinations of string loop corrections, leading order $\alpha^{\prime 3}$$R^4$-correction, higher derivative $F^{4}$ corrections as well as our new ingredient redefinition of the modulus. Since recent Dark Energy Spectroscopic Instrument (DESI) results appear to favour a dynamical explanation for late-time acceleration over a simple cosmological constant, exploring quintessence offers a more suitable approach. In this lore, we also examine the quintessence sector to complete our model and account for both early- and late-time
cosmic acceleration. In this framework, the poly-instanton correction generates a potential along the axionic directions, and we find that the resulting quintessence behaviour and the subsequent cosmological predictions about dark matter closely resemble the predictions of the original fibre inflation scenario studied earlier.
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All authors Dibya Chakraborty, Mishaal Hai, Sayeda Tashnuba Jahan, Ahmed Rakin Kamal, Md Shaikot Jahan Shuvo
Astrophysics of Galaxies
Beyond the Monsters: A More Complete Census of Black Hole Activity at Cosmic Dawn
Madisyn Brooks, Jonathan R. Trump, Raymond C. Simons et al. (+19 more)
JWST has revealed an abundance of low-luminosity active
galactic nuclei (AGN) at high
redshifts ($z > 3$), pushing the limits of black hole (BH) science in the early Universe. Results have claimed that these BHs are significantly more massive than expected from the BH mass-host
galaxy stellar mass relation derived from the local Universe. We present a comprehensive census of the BH populations in the early Universe through a detailed stacking analysis of
galaxy populations, binned by luminosity and
redshift, using JWST spectroscopy from the CEERS, JADES, RUBIES, and GLASS extragalactic deep field surveys. Broad H$\alpha$ detections in $31\%$ of the stacked spectra (5/16 bins) imply median BH masses of $10^{5.21} - 10^{6.13}~ \rm{M_{\odot}}$ and the stacked SEDs of these bins indicate median
stellar masses of $10^{7.84} - 10^{8.56} ~\rm{M_{\odot}}$. This suggests that the median
galaxy hosts a BH that is at most a factor of 10 times over-massive compared to its host
galaxy and lies closer to the locally derived $M_{BH}-M_*$ relation. We investigate the seeding properties of the inferred BHs and find that they can be well-explained by a light
stellar remnant seed undergoing moderate Eddington
accretion. Our results indicate that individual detections of AGN are more likely to sample the upper envelope of the $M_{BH}-M_*$ distribution, while stacking on “normal"
galaxies and searching for AGN signatures can overcome the selection bias of individual detections.
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All authors Madisyn Brooks, Jonathan R. Trump, Raymond C. Simons, Justin Cole, Anthony J. Taylor, Micaela B. Bagley, Steven L. Finkelstein, Kelcey Davis, Ricardio O. Amorín, Bren E. Backhaus, Nikko J. Cleri, Mauro Giavalisco, Norman A. Grogin, Michaela Hirschmann, Benne W. Holwerda, Marc Huertas-Company, Jeyhan S. Kartaltepe, Dale D. Kocevksi, Anton M. Koekemoer, Ray A. Lucas, Fabio Pacucci, Xin Wang
Astrophysics of Galaxies
Metal enrichment of galaxies in a massive node of the Cosmic Web at $z \sim 3$
Xiaohan Wang, S. Cantalupo, Weichen Wang et al. (+8 more)
We present the mass-
metallicity relation for
star-forming
galaxies in the MUSE
Quasar Nebula 01 (MQN01) field, a massive
cosmic web node at $z \sim 3.245$, hosting one of the largest overdensities of
galaxies and AGNs found so far at $z > 3$. Through James Webb Space
Telescope (JWST) Near Infrared Spectrograph (NIRSpec) spectra and images from JWST and Hubble Space
Telescope (HST), we identify a sample of 9
star-forming
galaxies in the MQN01 field with detection of nebular emission lines ($\rm H\beta$, [OIII], $\rm H\alpha$, [NII]), covering the mass range of $\rm 10^{7.5}M_\odot - 10^{10.5}M_\odot$. We present the relations of the emission-line flux ratios versus
stellar mass for the sample and derive the gas-phase
metallicity based on the strong line diagnostics of [OIII]$\lambda5008$/$\rm H\beta$ and [NII]$\lambda6585$/$\rm H\alpha$. Compared to the typical, field
galaxies at similar
redshifts, MQN01
galaxies show relatively higher [NII]$\lambda6585$/$\rm H\alpha$ and lower [OIII]$\lambda5008$/$\rm H\beta$ at the same
stellar mass, which implies a higher
metallicity by about $0.25\pm 0.07$ dex with respect to the field mass-
metallicity relation. These differences are decreased considering the “Fundamental
Metallicity Relation”, i.e. if the
galaxies'
Star Formation Rates (SFR) are also taken into account. We argue that these results are consistent with a scenario in which
galaxies in overdense regions assemble their
stellar mass more efficiently (or, equivalently, start forming at earlier epochs) compared to field
galaxies at similar
redshifts.
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All authors Xiaohan Wang, S. Cantalupo, Weichen Wang, M. Galbiati, Charles C. Steidel, A. Pensabene, Shude Mao, A. Travascio, T. Lazeyras, N. Ledos, G. Quadri
Cosmology and Nongalactic Astrophysics
Connecting clustering and the cosmic web:Observational constraints on secondary halo bias
Facundo Rodriguez and Antonio D. Montero-Dorta
Cosmological simulations predict significant secondary dependencies of
halo clustering on internal properties and environment. Detecting these subtle signals in observational data remains challenging, with important ramifications for
galaxy evolution and cosmology. We probe secondary
halo bias in observational survey data, using
galaxy groups as dark matter
halo proxies. We quantify secondary bias using central
galaxy colour and environmental diagnostics. We use an extended, refined
galaxy group catalogue from the Sloan Digital Sky Survey. Secondary bias is defined as any deviation in group clustering strength at fixed mass, quantified through the projected two-point correlation function. Our environmental analysis uses DisPerSE to compute distances to critical points of the density field, incorporating local group overdensity measurements on multiple scales. We robustly detect several forms of secondary bias in the clustering of
galaxy groups. At fixed mass, groups hosting red central
galaxies are more strongly clustered than those with blue centrals, with $b_{\rm relative}$ ranging from $\sim 1.2$ for the 15% reddest centrals to $\sim 0.8$ for the bluest ones. Environmental dependencies based on
cosmic-web distances are also present, though significantly weaker and largely mass-independent. The strongest signal arises from local overdensity: groups in the densest 15% of environments reach $b_{\rm relative} \sim 1.4$, while those in the least dense regions fall to $b_{\rm relative} \sim 0.7$. These results establish a clear observational hierarchy for secondary
halo bias. The colour of central
galaxies correlates with the local group overdensity, which, in turn, correlates with the bias at fixed group mass. Assuming that central
galaxy colour traces
halo assembly history, this three-stage picture offers a conceptual link between our results and
halo assembly bias.
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Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc
Periodic Gravitational Lensing with Oscillating Boson Stars
Xing-Yu Yang, Tan Chen and Rong-Gen Cai
We show that oscillating (real-scalar)
boson stars generically host an oscillating radial caustic. Sources near this caustic cross it every half period, thereby producing periodic caustic-crossing
lensing. The resulting observables are phase locked to the lens oscillation: image-pair creation or annihilation, changing image morphology, achromatic photometric spikes, and astrometric motion. This signal provides a distinctive target for time-domain astronomy, and its detection would reveal an intrinsically time-dependent compact dark-sector object. Event-number estimates indicate a measurable discovery space with current astrometric and high-cadence photometric surveys, while null searches would constrain the abundance of such objects as dark matter. The predictions rely only on the dynamics of real-scalar condensates and extend naturally to self-interacting real scalars, including axionlike particles, and to ultralight vector
bosons.
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High Energy Astrophysical Phenomena
Role of magnetic reconnection in blazar variability using numerical simulation
Chandan Kumar Das, Bhargav Vaidya, Amit Shukla et al. (+2 more)
Fast $\gamma$-ray variability in blazars remains a central puzzle in high-energy astrophysics, challenging standard shock acceleration models. Blazars, a subclass of active
galactic nuclei (AGN) with jets pointed close to our line of sight, offer a unique view into jet dynamics. Blazar $\gamma$-ray light curves exhibit rapid, high-amplitude
flares that point to promising alternative dissipation mechanisms such as
magnetic reconnection. This study uses three-dimensional relativistic magnetohydrodynamic (RMHD) and resistive relativistic magnetohydrodynamic (ResRMHD) simulations with the PLUTO code to explore
magnetic reconnection in turbulent, magnetized
plasma columns. Focusing on current-driven kink instabilities, we identify the formation of current sheets due to
magnetic reconnection, leading to plasmoid formation. We develop a novel technique combining hierarchical structure analysis and reconnection diagnostics to identify reconnecting current sheets. A statistical analysis of their geometry and orientation reveals a smaller subset that aligns closely with the jet axis, consistent with the jet-in-jet model. These structures can generate relativistically moving plasmoids with significant Doppler boosting, offering a plausible mechanism for the fast
flares superimposed on slowly varying blazar light curves. These findings provide new insights into the
plasma dynamics of relativistic jets and strengthen the case for
magnetic reconnection as a key mechanism in blazar $\gamma$-ray variability.
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All authors Chandan Kumar Das, Bhargav Vaidya, Amit Shukla, Giancarlo Mattia, Karl Mannheim
Cosmology and Nongalactic Astrophysics
In medio stat virtus: enrichment history in poor galaxy clusters
G. Riva, S. Ghizzardi, S. Molendi et al. (+6 more)
The enrichment history of
galaxy clusters and groups remains far from being fully understood. Recent measurements in massive clusters have revealed remarkably flat iron abundance profiles out to the outskirts, suggesting that similar enrichment processes have occurred for all systems. In contrast, abundance profiles in
galaxy groups have sometimes been measured to decline with radius, challenging our understanding of the physical processes at these scales. In this paper, we present a pilot study aimed at accurately measuring the iron abundance profiles of MKW3s, A2589, and Hydra A, three poor clusters with total masses of $M_{500} \simeq 2.0-2.5 \times 10^{14}$ M$_\odot$, intermediate between the scales of
galaxy groups and massive clusters. Using XMM-Newton to obtain nearly complete azimuthal coverage of the outer regions of these systems, we show that abundance measurements in the outskirts are more likely to be limited by systematics than by statistical errors. In particular, inaccurate modelling of the soft X-ray background can significantly bias
metallicity estimates in regions where the cluster emission is faint. Once these systematics are properly accounted for, the abundance profiles of all three clusters appear to be flat at $Z \sim 0.3$ Z$_{\odot}$, in agreement with values observed in massive clusters. Using available
stellar mass estimates, we also computed their iron yields, thereby beginning to probe a largely unexplored mass range. We find $Y_{Fe,500} = 2.68\pm0.34$, $2.54\pm0.64$, and $7.51\pm1.47$ Z$_{\odot}$ for MKW3s, A2589, and Hydra A, respectively, spanning the transition regime between
galaxy groups and massive clusters. Future observations of systems with temperatures of $2-4$ keV will be essential to further populate this intermediate-mass regime and to draw firmer conclusions on the chemical enrichment history of
galaxy systems across the full mass scale.
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All authors G. Riva, S. Ghizzardi, S. Molendi, M. Balboni, I. Bartalucci, S. De Grandi, F. Gastaldello, L. Lovisari, M. Rossetti
Astrophysics of Galaxies
Tracing AGN-Galaxy Co-Evolution with UV Line-Selected Obscured AGN
Luigi Barchiesi, Lucia Marchetti, Mattia Vaccari et al. (+11 more)
Understanding black hole-
galaxy co-
evolution and the role of AGN feedback requires complete AGN samples, including heavily obscured systems. In this work, we present the first UV line-selected ([Nev]3426 and CIV1549) sample of obscured AGN with full X-ray-to-
radio coverage, assembled by combining data from the Chandra COSMOS Legacy survey, the COSMOS2020 catalogue, IR photometry from XID+, and
radio observations from the VLA and MIGHTEE surveys. Using CIGALE to perform spectral energy distribution (SED) fitting, we analyse 184 obscured AGN at 0.6 < z < 1.2 and 1.5 < z < 3.1, enabling detailed measurements of AGN and host
galaxy properties, and direct comparison with SIMBA hydrodynamical simulations. We find that X-ray and
radio data are essential for accurate SED fits, with the
radio band proving critical when X-ray detections are missing or in cases of poor IR coverage. Comparisons with matched non-active
galaxies and simulations suggest that the [NeV]-selected sources are in a pre-quenching stage, while the CIV-selected ones are likely quenched by AGN activity. Our results indicate that [NeV] and CIV selections target
galaxies in a transient phase of their co-
evolution, characterised by intense, obscured
accretion, and pave the way for future extensions with upcoming large area high-z spectroscopic surveys.
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All authors Luigi Barchiesi, Lucia Marchetti, Mattia Vaccari, Cristian Vignali, Francesca Pozzi, Isabella Prandoni, Roberto Gilli, Marco Mignoli, Jose Afonso, Veeresh Singh, Catherine Hale, Ian Heywood, Matt Jarvis, Imogen Whittam
Cosmology and Nongalactic Astrophysics
Towards Reconciling Reionization with JWST: The Role of Bright Galaxies and Strong Feedback
Ankita Bera, Sultan Hassan, Robert Feldmann et al. (+2 more)
The elevated UV luminosity functions (UVLF) from recent James Webb Space
Telescope (JWST) have challenged the viability of existing theoretical models. To address this, we use a semi-analytical framework – which couples a physically motivated source model derived from radiative-transfer hydrodynamic simulations of reionization with a Markov Chain Monte Carlo sampler – to perform a joint calibration to JWST
galaxy surveys (UVLF, $\phi_{\rm UV}$ and UV luminosity density, $\rho_{\rm UV}$) and reionization-era observables (ionizing emissivity, $\dot{N}_{\rm ion}$, neutral hydrogen fraction, $x_{\rm HI}$, and Thomson optical depth, $\tau$). We find that models with weak feedback and a higher contribution from faint
galaxies reproduce the reionization observables but struggle to match the elevated JWST UVLF at $z > 9$. In contrast, models with stronger feedback (i.e., rapid
redshift evolution) and a higher contribution from bright
galaxies successfully reproduce JWST UVLF at $z \geq 10$, but over-estimate the bright end at $z < 9$. The strong-feedback model constrained by JWST UVLF predicts a more gradual and extended reionization history, as opposed to the sudden reionization seen in the weak-feedback models. This extended nature of reionization ($z\sim 16$ - $6$) yields an optical depth consistent (at 2-$\sigma$) with the
Cosmic Microwave Background (CMB) constraint, thereby alleviating the
photon-budget crisis. In both scenarios, reionization is complete by $z \sim 6$, consistent with current data. Our analysis highlights the importance of accurately modeling feedback and ionizing emissivities from different source populations during the first billion years after the Big Bang.
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All authors Ankita Bera, Sultan Hassan, Robert Feldmann, Romeel Davé, Kristian Finlator
High Energy Astrophysical Phenomena · Cross-listed from hep-ph
Hawking heating of neutron stars by dark matter
Akash Kumar Saha, Abhishek Dubey and Nirmal Raj
Interactions with particle dark matter could brighten old, isolated
neutron stars to thermal luminosities detectable at current and next-generation
telescopes. We present a novel mechanism for such signals. Non-annihilating (e.g., asymmetric) dark matter capturing in a
neutron star could form a small black hole in its core, which could then rapidly evaporate away. If black holes form and evaporate within the cooling timescale of the
neutron star, periodic episodes of black hole evaporation could impart a steady-state
stellar luminosity, providing a source of heat additional to the kinetic energy of dark matter during capture. Consequently, we obtain sensitivities to dark matter-nucleon cross sections that are stronger than that from dark kinetic heating by a factor of a few for > $10^4$ GeV (> $10^{10}$ GeV) mass of
spin-0 (
spin-1/2) dark matter.
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Astrophysics of Galaxies
Mind the Information Gap: Unveiling Detailed Morphologies of z 0.5-1.0 Galaxies with SLACS Strong Lenses and Data-Driven Analysis
Ronan Legin, Connor Stone, Alexandre Adam et al. (+5 more)
We present new state-of-the-art lens models for strong gravitational
lensing systems from the Sloan Lens ACS (SLACS) survey, developed within a
Bayesian framework that employs high-dimensional (pixellated), data-driven priors for the background source, foreground lens light, and point-spread function (PSF). Unlike conventional methods, our approach delivers high-resolution reconstructions of all major physical components of the
lensing system and substantially reduces model-data residuals compared to previous work. For the majority of 30
lensing systems analyzed, we also provide posterior samples capturing the full uncertainty of each physical model parameter. The reconstructions of the background sources reveal high significance morphological structures as small as 200 parsecs in
galaxies at
redshifts of z 0.5-1.0, demonstrating the power of strong
lensing and the analysis method to be used as a
cosmic telescope to study the high
redshift universe. This study marks the first application of data-driven generative priors to modeling real strong-
lensing data and establishes a new
benchmark for strong
lensing precision modeling in the era of large-scale imaging surveys.
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All authors Ronan Legin, Connor Stone, Alexandre Adam, Gabriel Missael Barco, Adam Coogan, Nikolay Malkin, Laurence Perreault-Levasseur, Yashar Hezaveh
Instrumentation and Methods for Astrophysics
Pixellated Posterior Sampling of Point Spread Functions in Astronomical Images
Connor Stone, Ronan Legin, Alexandre Adam et al. (+4 more)
We introduce a novel framework for upsampled Point Spread Function (PSF) modeling using pixel-level
Bayesian inference. Accurate PSF characterization is critical for precision measurements in many fields including: weak
lensing, astrometry, and photometry. Our method defines the posterior distribution of the pixelized PSF model through the combination of an analytic Gaussian likelihood and a highly expressive generative
diffusion model prior, trained on a library of HST ePSF templates. Compared to traditional methods (parametric Moffat, ePSF template-based, and regularized likelihood), we demonstrate that our PSF models achieve orders of magnitude higher likelihood and residuals consistent with noise, all while remaining visually realistic. Further, the method applies even for faint and heavily masked point sources, merely producing a broader posterior. By recovering a realistic, pixel-level posterior distribution, our technique enables the first meaningful propagation of detailed PSF morphological uncertainty in downstream analysis. An implementation of our posterior sampling procedure is available on GitHub.
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All authors Connor Stone, Ronan Legin, Alexandre Adam, Esmeralda Whitammer, Gabriel Missael Barco, Laurence Perreaul-Levasseur, Yashar Hezaveh
High Energy Astrophysical Phenomena
X-ray, optical, and radio follow-up of five thermally emitting isolated neutron star candidates
J. Kurpas, A. M. Pires, A. D. Schwope et al. (+7 more)
We report on follow-up observations with XMM-Newton, the FORS2 instrument at the ESO-VLT, and FAST, aiming to characterise the nature of five thermally emitting isolated
neutron star (INS) candidates recently discovered from searches in the footprint of the Spectrum Roentgen Gamma (SRG)/eROSITA All-sky Survey. We find that the X-ray spectra are predominantly thermal and can be described by low-absorbed blackbody models with effective temperatures ranging from 50 to 210 eV. In two sources, the spectra also show narrow absorption features at $300 - 400$ eV. Additional non-thermal emission components are not detected in any of the five candidates. The soft X-ray emission, the absence of optical counterparts in four sources, and the consequent large X-ray-to-optical flux ratios $>3000 - 5400$ confirm their INS nature. For the remaining source, eRASSU J144516.0-374428, the available data do not allow a confident exclusion of an active
galactic nucleus nature. However, if the source is
Galactic, the small inferred X-ray emitting region is reminiscent of a heated
pulsar polar cap, possibly pointing to a binary
pulsar nature. X-ray timing searches do not detect significant modulations in all candidates, implying pulsed fraction upper limits of 13 - 19% ($0.001-13.5$ Hz). The absence of pulsations in the FAST observations targeting eRASSU J081952.1-131930 and eRASSU J084046.2-115222 excludes periodic magnetospheric emission at 1 - 1.5 GHz with an $8\sigma$ significance down to 4.08 $\mu$Jy and 2.72 $\mu$Jy, respectively. The long-term X-ray emission of all sources does not imply significant variability. Additional observations are warranted to establish exact
neutron star types. At the same time, the confirmation of the predominantly thermal
neutron star nature in four additional sources highlights the power of SRG/eROSITA to complement the
Galactic INS population.
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All authors J. Kurpas, A. M. Pires, A. D. Schwope, B. Li, D. Yin, F. Haberl, M. Krumpe, S. Sheth, I. Traulsen, Z. L. Zhang
Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc
Searching Stochastic Gravitational Wave Background Landscape Across Frequency Bands
Yunjia Bao, Tore Boybeyi, Vuk Mandic et al. (+1 more)
Gravitational wave (GW) astrophysics is entering a multi-band era with upcoming GW detectors, enabling detailed mapping of the
stochastic GW background across vast frequencies. We highlight this potential via a new physics scenario: hybrid topological defects from a two-step phase transition separated by inflation. We develop a general pipeline to analyze experimental exclusions and apply it to this model. The model offers a possible explanation of the
pulsar timing array signal at low frequencies, and future experiments (LISA/
Cosmic Explorer/Einstein
Telescope) will confirm or rule it out via the higher-frequency probes, showcasing the power of multi-band constraints.
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All authors Yunjia Bao, Tore Boybeyi, Vuk Mandic, Lian-Tao Wang
Earth and Planetary Astrophysics
Chemical and Isotopic Homogeneity Between the L Dwarf CD-35 2722 B and its Early M Host Star
Gavin Wang, Jerry Xuan, Darío Picos et al. (+29 more)
CD-35 2722 B is an L
dwarf companion to the nearby, $\sim 50-200$ Myr old M1
dwarf CD-35 2722 A. We present a detailed analysis of both objects using high-resolution ($R \sim 35,000$) $K$ band spectroscopy from the Keck
Planet Imager and Characterizer (KPIC) combined with archival photometry. With a mass of $30^{+5}_{-4} M_{\mathrm{Jup}}$ (
planet-to-host mass ratio 0.05) and projected separation of $67\pm4$ AU from its host, CD-35 2722 B likely formed via gravitational instability. We explore whether the chemical composition of the system tells a similar story. Accounting for systematic uncertainties, we find $\mathrm{[M/H]}=-0.16^{+0.03}_{-0.02} \mathrm{(stat)} \pm 0.25 \mathrm{(sys)}$ dex and $^{12}\mathrm{C}/^{13}\mathrm{C}=132^{+20}_{-14}$ for the host, and $\mathrm{[M/H]}=0.27^{+0.07}_{-0.06} (\mathrm{stat}) \pm 0.12 (\mathrm{sys})$ dex, $^{12}\mathrm{CO}/^{13}\mathrm{CO}=159^{+33}_{-24} \mathrm{(stat)}^{+40}_{-33} \mathrm{(sys)}$, and $\mathrm{C/O} = 0.55 \pm 0.01 (\mathrm{stat}) \pm 0.04 (\mathrm{sys})$ for the companion. The chemical compositions for the brown
dwarf and host
star agree within the $1.5\sigma$ level, supporting a scenario where CD-35 2722 B formed via gravitational instability. We do not find evidence for clouds on CD-35 2722 B despite it being a photometrically red mid-L
dwarf and thus expected to be quite cloudy. We retrieve a temperature structure which is more isothermal than models and investigate its impact on our measurements, finding that constraining the temperature structure to self-consistent models does not significantly impact our retrieved chemical properties. Our observations highlight the need for data from complementary wavelength ranges to verify the presence of aerosols in likely cloudy L
dwarfs.
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All authors Gavin Wang, Jerry Xuan, Darío Picos, Zhoujian Zhang, Yapeng Zhang, Dimitri Mawet, Chih-Chun Hsu, Jason Wang, Geoffrey Blake, Jean-Baptiste Ruffio, Katelyn Horstman, Ben Sappey, Yinzi Xin, Luke Finnerty, Daniel Echeverri, Nemanja Jovanovic, Ashley Baker, Randy Bartos, Benjamin Calvin, Sylvain Cetre, Jacques-Robert Delorme, Greg Doppmann, Michael Fitzgerald, Joshua Liberman, Ronald López, Evan Morris, Jacklyn Pezzato-Rovner, Caprice Phillips, Tobias Schofield, Andrew Skemer, James Wallace, Ji Wang
Astrophysics of Galaxies
Estimating the masses of Narrow line Seyfert 1 galaxies using damped random walk method
Rachana, M. Vivek and Yue Shen
Narrow-line Seyfert 1
galaxies (NLSy1s) are a subclass of active
galactic nuclei (AGNs), commonly associated with rapidly accreting, relatively low-mass black holes ($10^6$ - $10^8 M_\odot$) hosted in spiral
galaxies. Although typically considered to have high Eddington ratios, recent observations, particularly of $\gamma$-ray-emitting NLSy1s, have raised questions about their true black hole masses, with some estimates approaching those of Broad-line Seyfert 1 (BLSy1) systems. In this work, we present the recalibrated mass estimations for a large sample of NLSy1s
galaxies with z $<0.8$. We apply the damped random walk (DRW) formalism to a comparison set of 1,141 NLSy1 and 1,143 BLSy1
galaxies, matched in
redshift and bolometric luminosity using SDSS DR17 spectroscopy. Our analysis employs a multivariate calibration that incorporates both the Eddington ratio and the rest-frame wavelength to refine the mass estimates. We obtain median DRW-based black hole masses of $\text{log}(M_{\text{BH}}^{\text{DRW}}/M_\odot) = 6.25 \pm 0.65$ for NLSy1s and $7.07 \pm 0.67$ for BLSy1s, in agreement with their respective virial mass distributions. Furthermore, we identify strong inverse trends between the variability amplitude and both optical luminosity and FeII emission strength, consistent with a scenario where higher
accretion rates suppress long-term optical variability. These findings reinforce the view that NLSy1s harbor smaller black holes and highlight the value of variability-based approaches in tracing AGN
accretion properties.
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Solar and Stellar Astrophysics
Constraining properties of dust formed in Wolf-Rayet binary WR 112 using mid-infrared and millimeter observations
Donglin Wu, Yinuo Han, Peredur M. Williams et al. (+9 more)
Binaries that host a carbon-rich Wolf-Rayet (WC)
star and an OB-type companion can be copious
dust producers. Yet the properties of
dust, particularly the grain size distribution, in these systems remain uncertain. We present Band 6 observations of WR 112 by the Atacama Large Millimeter/submillimeter Array
telescope (ALMA), which are the first millimeter observations of a WC binary system capable of resolving its
dust emission. By combining ALMA observations with James Webb Space
Telescope (JWST) images, we were able to analyze the spatially resolved spectral energy distribution (SED) of WR 112. We found that the SEDs are consistent with emissions from hydrogen-poor amorphous carbon grains. Notably, our results also suggest that the majority of grains in the system have radii below one micrometer, and the extended
dust structures are dominated by nanometer-sized grains. Among four parameterizations of the grain radius distribution that we tested, a bimodal distribution, with abundant nanometer-sized grains and a secondary population of 0.1-micron grains, best reproduces the observed SED. This bimodal distribution helps to reconcile the previously conflicting grain size estimates reported for WR 112 and for other WC systems. We hypothesize that
dust destruction mechanisms such as radiative torque disruption and radiative-driven sublimation are responsible for driving the system to the bimodal grain size distribution.
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All authors Donglin Wu, Yinuo Han, Peredur M. Williams, Takashi Onaka, Joseph R. Callingham, Matthew J. Hankins, Peter Tuthill, Ryan M. Lau, Gerd Weigelt, Benjamin J. S. Pope, Noel D. Richardson, Anthony Moffat