Solar and Stellar Astrophysics
Protoplanetary Disk Evolution in a Low-Metallicity Environment: JWST's First Mid-Infrared Census of Low-Mass Stars
Chikako Yasui, Natsuko Izumi, Masao Saito et al. (+3 more)
This study presents the first high-resolution, high-sensitivity mid-infrared (MIR) investigation of protoplanetary disks in a low-
metallicity environment, using JWST/NIRCam and MIRI observations of Digel Cloud 2, a
star-forming region in the outer
Galaxy ($D \simeq 8$ kpc, ${\rm [M/H]} \simeq -0.7$ dex). It hosts two very young ($\sim$0.1 Myr) embedded clusters, Cloud 2-N and Cloud 2-S, offering a window into disk
evolution under conditions analogous to the early universe, where low
metallicity implies reduced
dust content. Imaging across 1-20 $\mu$m, including F770W and complementary bands (F356W, F444W, F405N), enables probing disk properties with unprecedented spatial resolution and
stellar mass sensitivity down to $\sim$0.1 $M_\odot$. Among 89 and 95 sources detected in F770W in Cloud 2-N and 2-S, respectively, we identify candidate
stellar-mass cluster members using infrared photometry, from which
stellar mass and extinction are estimated. Among these, $\simeq$75 % retain optically thick disks in both clusters based on MIR SED slopes, consistent with similarly aged
solar-
metallicity regions. In contrast, a lack of 2 $\mu$m excess suggests diminished inner disk emission, possibly due to enhanced silicate grains with low sublimation temperatures. Using the F405N narrow-band filter covering Br$\alpha$, we detect
accretion signatures in $\simeq$35 % of sources selected by extinction criteria, with rates $\gtrsim$10$^{-6}$ $M_\odot$ yr$^{-1}$, comparable to or exceeding those in nearby low-mass
stars. Brown
dwarf candidates, identified across multiple bands including F770W and shorter wavelengths, exhibit a high disk fraction of $\sim$75 %, indicating robust disk retention across mass ranges even under low-
metallicity conditions.
Read the full abstract ▾
All authors Chikako Yasui, Natsuko Izumi, Masao Saito, Ryan M. Lau, Naoto Kobayashi, Michael E. Ressler
High Energy Astrophysical Phenomena · Cross-listed from hep-ph
Fermion scattering in a Bose-Einstein condensate
César E. Echevarría, José F. Nieves, Francisco Orbe et al. (+1 more)
In a recent work, we considered the propagation of
fermions in the background of a scalar Bose-Einstein (BE) condensate. Using some illustrative Yukawa-type coupling models between the
fermions and the scalar fields, we determined the dispersion relations of the
fermions and the scalar modes in various models. To complement that work, here we consider the corresponding
fermion spinors and propagators, which are required for the calculation of rates of processes involving the
fermions, as well as the thermal, and/or higher order, corrections to such rates. We obtain and present here concise formulas which are useful for those applications. As an application and for illustrative purposes we specifically calculate the rate for a generic
fermion (which we denote by $\chi$) with the
fermions in the BE background, using commonly used models for the
fermion interactions. Due to the fact that the background
fermion dispersion relations are helicity dependent, the kinematics have some unique and non-standard features. For example, at a particular value of the momentum one of the
fermion modes has zero group velocity, which leads to a singularity in the scattering rate of the type of the Van Hove singularity in the density of states of some condensed matter systems. The results of the framework presented here, besides their merit in their own right, can be useful in specific contexts and applications, such as
cosmic-ray electron cooling through dark matter-electron scattering, and similar ones involving
neutrino and/or electron propagation in a scalar Dark Matter background.
Read the full abstract ▾
All authors César E. Echevarría, José F. Nieves, Francisco Orbe, Sarira Sahu
Earth and Planetary Astrophysics
On The Detection of Digiorno-like Objects in the Flavor Zone
Logan A. Pearce and Sue D'Oh Nym
Aims: This work proposes a new SETI search methodology under the assumption that a sufficiently advanced civilization could skip the middle man of converting starlight to energy to food preparation, and could directly harness their
star's energy for food prep. Methods: We define the concept of the
Flavor Zone (FZ): the optimal distance from a
star for cooking food. To develop this definition we propose the toy model of a Digiorno-Like Object (DLO) and define the FZ as the regime for optimal cooking according to package directions. We examine the effect of orbit on DLO cooking times and paradigms. Finally, we study the feasibility of detection of DLOs in their FZs with current technology. Results: We determined that DLOs aren't detectable with current technology nor should anyone ever try.
Read the full abstract ▾
Instrumentation and Methods for Astrophysics
Reducing the Virgo site infrastructure noise in preparation of the O4 observing run
Irene Fiori, Federico Paoletti, Roberto Passaquieti et al. (+5 more)
The heating, ventilation and air conditioning systems serving the experimental halls of the Virgo gravitational wave interferometer generate low-frequency noise - namely below 100 Hz - of seismic, acoustic, and electromagnetic origin. Such disturbances have repeatedly affected the interferometer sensitivity throughout its operational history, with particularly notable impacts during the third observing run. In preparation for the fourth run, a comprehensive investigation was carried out to identify the most critical noise sources within this infrastructure and to trace their transmission paths into the experimental areas. This manuscript presents the methodology and results of the noise characterization campaign, together with the design, implementation and assessment of targeted mitigation measures. The technical solutions adopted, along with the operational best practices developed, provide valuable guidance for the design of low-noise environments in future gravitational-wave observatories.
Read the full abstract ▾
All authors Irene Fiori, Federico Paoletti, Roberto Passaquieti, Maria Concetta Tringali, Lorenzo Pierini, Francesca Bucci, Massimo Lenti, Alessandro Longo
Instrumentation and Methods for Astrophysics
New Paradigms in Pasta: Introducing $\mathtt{GF \ pastamarkers}$ for Enhanced Inclusivity and Productivity
Julian Falcone and Nabanita Das
Informative data visualization methods are key to the clear and efficient communication of myriad forms of data. The PASTA Collaboration has made substantial contributions to the field of data visualization through $\mathtt{pastamarkers}$, a Python-based package that utilizes various types of pasta as data markers to create engaging plots. This work introduces $\mathtt{GF \ pastamarkers}$, an extension of $\mathtt{pastamarkers}$ that utilizes the tenuous structure of gluten free (GF) pasta to meet the needs of the GF population. The implementation of $\mathtt{GF \ pastamarkers}$ employs an exponential crumbling factor ($CF$), which benefits authors by encouraging clearer and more concise scientific articles, thereby leading to more effective manuscripts and proposals.
Read the full abstract ▾
High Energy Astrophysical Phenomena · Cross-listed from hep-ph
Constraining The Neutrino-Nucleon Cross Section with the Ultrahigh-Energy KM3NeT Event
Toni Bertólez-Martínez and Dan Hooper
KM3NeT's detection of a
muon track produced by a $\sim 220 \, {\rm PeV}$
neutrino provides an opportunity to probe physics at center-of-momentum energies greater than those probed by the Large
Hadron Collider or other existing particle accelerators. In this study, we use this single event to place an upper limit on the
neutrino-nucleon cross section of $\sigma_{\nu N} < 40 \, \sigma_{\nu N}^{\rm SM}$ at $E_{\rm CM} \sim 20 \, {\rm TeV}$. This result can be used to constrain a variety of scenarios beyond the Standard Model. With future very large volume
neutrino telescopes, constraints on the
neutrino-nucleon scattering cross section are expected to become substantially more stringent and, in some scenarios, could become competitive with accelerator probes of new physics.
Read the full abstract ▾
Solar and Stellar Astrophysics
The Binary-Binary Hierarchical System XY Leo: A Laboratory for Stellar Activity and Concealed Companions
D. Koçak, K. Yakut and C. A. Tout
The hierarchical multiple system XY Leo, despite nearly 90 yr of observations, remains enigmatic. It offers a unique testbed for close binary
evolution, involving processes such as mass transfer, angular momentum loss, and the von Zeipel–Kozai–Lidov (ZKL) mechanism. Previously identified as a quadruple system, XY Leo shows long-term orbital period modulations. Our new ground-based and Transiting
Exoplanet Survey Satellite data suggest that these may stem from either
magnetic cycles or the influence of an unseen companion. While the latter remains speculative, both scenarios are discussed within a unified framework. Using all available photometric and spectroscopic data, we derived ultraprecise physical parameters for the contact binary XY Leo A as $M_{\rm A1}=0.629\pm0.009\,M_{\odot}$, $M_{\rm A2}=0.865\pm0.012\,M_{\odot}$, $R_{\rm A1}=0.739\pm0.007\,R_{\odot}$, $R_{\rm A2}=0.855\pm0.008\,R_{\odot}$, $L_{\rm A1}=0.271\pm0.026\,L_{\odot}$, $L_{\rm A2}=0.288\pm0.030\,L_{\odot}$, and orbital separation $a_{\rm A}=2.078\pm0.010\,R_{\odot}$, based on simultaneous solutions of light and radial velocity curves. The detached binary subsystem XY Leo B is confirmed to be on a wide $\sim 20$-year orbit around the contact system. A second $\sim 23$-year modulation is also detected, which may arise from either
stellar magnetic activity or an additional unseen companion. After removing both trends, a coherent residual modulation with a characteristic timescale of $14.2 \pm 0.8$~yr remains in the $O$–$C$ diagram, consistent with a
magnetic activity cycle of Applegate type. We modeled XY Leo A with the Cambridge
STARS (EV/TWIN) code under non-conservative
evolution, finding strong agreement between the tracks and observed parameters, highlighting the system's value for testing multiple-
star evolution.
Read the full abstract ▾
Earth and Planetary Astrophysics
Hydrogen-helium immiscibility boundary in gas-giant planetary interiors from machine-learning molecular dynamics
Xiaoyu Wang, Sebastien Hamel and Bingqing Cheng
The location of the hydrogen-helium (H/He) immiscibility boundary controls whether and where helium rain occurs in
giant planets, yet it remains uncertain because high-pressure experiments are challenging and ab initio simulations are limited in system size and simulation time. We map this boundary by computing composition-dependent chemical potentials from large-scale molecular dynamics driven by machine learning potentials trained on three density functional approximations (PBE, vdW-DF, and the hybrid HSE). Across the pressure range of 100-1000 GPa, the demixing temperatures are typically ~2000 K lower than previous ab initio simulations using small system sizes, and this discrepancy is larger than the estimated error from the chosen density functionals, machine learning potentials, neglect of
nuclear quantum effects, and statistical uncertainties. Fitting the H/He mixing free energy to a Redlich-Kister regular solution model rationalizes the thermodynamic driving force for phase separation and provides a predictive representation of the boundary. Comparing with current planetary interior profiles indicates that helium rain is plausible in Saturn but unlikely in the warmer interior of Jupiter. Our results narrow the uncertainty in the H/He immiscibility boundary and provide inputs for planetary models that couple demixing, heat transport, and composition gradients in gas
giants.
Read the full abstract ▾
Astrophysics of Galaxies
JWST MIRI-MRS observations of the Red Rectangle: AIB class transformation in the outer nebula
A. Ebenbichler, P. Moraga Baez, A. Candian et al. (+8 more)
Aims: We characterize the mid-infrared spectrum of the outer regions of the Red Rectangle nebula to probe the carbonaceous
dust and molecular content beyond the circumbinary disk. Methods: We present JWST MIRI-MRS observations of the SW whisker, extracted from three distinct environments: the biconical
outflow, the whisker itself, and the shadow region outside the
outflow. We compare these with an archival ISO-SWS observation of the inner nebula. Results: The JWST spectra display only classical AIB emission on a weak
dust continuum, with no signatures of the oxygen-rich circumbinary disk mineralogy nor of the rich molecular emission seen at optical wavelengths. The AIBs are predominantly Class A - in marked contrast to the exclusively Class B profiles previously reported for the inner regions - with systematic differences between the
outflow and shadow regions pointing to environmentally driven PAH processing.
Read the full abstract ▾
All authors A. Ebenbichler, P. Moraga Baez, A. Candian, E. Peeters, J. Cami, P.J. Sarre, A.N. Witt, I. Argyriou, B. Vandenbussche, H. Van Winckel, L.B.F.M. Waters
Instrumentation and Methods for Astrophysics
Sugar Rush: Improving Observing Productivity via Night Dessert
J.J. Charfman Jr, S. Hyman and N.T.S
Exhaustion and
brain fog during long nights observing is common, but can be ameliorated by raising one's blood sugar. In this white paper, we present a prototype method for facilitating a sugar rush during late-night crashes, which has the potential to boost observing productivity.
Read the full abstract ▾
Astrophysics of Galaxies
From Detection to Host Galaxy Identification: Precision Continuous Gravitational Wave Localization with a Few Anchor Pulsars
Chao-Fan Wen, Yi-Qin Chen, Shi-Yi Zhao et al. (+2 more)
Pulsar Timing Arrays (PTAs) are rapidly advancing toward the detection of continuous gravitational waves from individual supermassive binary black holes. While it is well established that coherently utilizing the “
pulsar term" requires astrometric distance uncertainties to be smaller than the gravitational wavelength, achieving this precision across an entire array is observationally prohibitive. Here, we demonstrate that achieving sub-wavelength precision for a few “anchor"
pulsars is sufficient to phase-lock the array and drastically shrink the sky-localization error. Using 20 years of realistically simulated data, we systematically evaluate the localization performance of a 25-
pulsar array containing three to six high-precision anchors. We show that while introducing three sub-wavelength anchors can reduce the 90% credible sky area by a factor of 30 in certain directions, expanding this high-precision subset to six anchor
pulsars ensures high-precision localizations across diverse source directions. Evaluating a representative set of sky directions, including local
galaxy clusters and the locations of maximum and minimum array sensitivity, this six-anchor configuration yields 90% credible localization areas ranging from $\sim 0.1$ to $9.2 \text{ deg}^2$ at a signal-to-noise ratio of 20. Furthermore, once this minimal subset crosses the sub-wavelength threshold, further reductions in distance uncertainty yield diminishing returns. This establishes a highly efficient near-term observational strategy: prioritizing intensive parallax campaigns for a small core of stable millisecond
pulsars provides a cost-effective pathway to precision multi-messenger astronomy.
Read the full abstract ▾
All authors Chao-Fan Wen, Yi-Qin Chen, Shi-Yi Zhao, Hao Ding, Xingjiang Zhu
Earth and Planetary Astrophysics
Plan 9: Detecting Atmospheric Deterrence Against Interstellar Monsters
David R. Rice and Michael J. Radke
Exoplanet atmospheres are usually discussed as tracers of
climate, chemistry, and habitability, but they may also preserve signatures of planetary defense. We consider three folklore-motivated deterrents against monsters: reduced organosulfur gases as anti-hematophage repellents, argentiferous reflective aerosols as anti-lycanthropic countermeasures, and haline aerosols as a counting problem for specters. We show that globally-mixed garlic-smelly levels of DMS/DMDS could produce observable mid-infrared transmission features, that silver hazes would show up as anomalous optical brightening, and that sea-salt lofting sustained by strong near-surface winds appears as muted spectra. None of these signatures is unique, which is precisely the observational challenge. A defended world may first appear merely sulfur-rich, bright, or hazy. Therefore, some atmospheres may encode not only biosignatures, but also evidence that the local biosphere has stopped being afraid of the dark.
Read the full abstract ▾
High Energy Astrophysical Phenomena
Survey of compact sources for pulsars and exotic objects – I. Overview and initial discoveries
Yogesh Maan, Apurba Bera, Dharam Vir Lal et al. (+4 more)
Targeted searches for
pulsars based on their counterparts in
radio images have resulted in the discovery of interesting
pulsars including the first ever discovered millisecond
pulsar (MSP). Here, we report the first results from our image-based survey of compact sources for
pulsars and exotic objects (SCOPE). SCOPE utilizes interferometric as well as time-domain observations to search for
radio pulsations as well as characterize the sources in the image-domain to identify their true nature. In the first stage of the SCOPE survey, we have used the
Giant Metrewave
Radio Telescope (GMRT) and the Green Bank
Telescope (GBT) to follow up a sample of 31 compact and steep-spectrum sources. We provide an overview of the survey, the sample selection, the search procedures, and present discoveries of two MSPs – PSR J1840+1102 and PSR J1827-0849. PSR J1840+1102 is a 1.6 ms
pulsar at the edge of the Scutum-Centaurus arm, while PSR J1827-0849 is the
radio counterpart of a gamma-ray
pulsar that was earlier thought to be
radio-quiet, and both the sources have very steep
radio spectra. Using the interferometric data, we also provide a morphological classification of all the sources, model and characterize their spectra and identify the resolved, extragalactic sources in our sample. We discuss these results in the context of future image-based
pulsar surveys.
Read the full abstract ▾
All authors Yogesh Maan, Apurba Bera, Dharam Vir Lal, Yash Bhusare, Preeti Kharb, Banshi Lal, Pikky Atri
Instrumentation and Methods for Astrophysics
Where to Search For Life: Evidence from narrative sources with established predictive efficacy
Elizabeth R Stanway
The search for habitable
planets, and even for “Earth 2.0”, is a major driver in contemporary astronomy. However selecting target fields to prioritise for such searches presents a challenge. Here we establish a statistical analysis of the appearance of constellation names in science fiction magazines of the pulp era, evaluating the most commonly mentioned constellations and thus those which the science fiction community collectively identify as the most likely locations to find life. Given that the predictive power of science fiction is well established, we suggest that these locations might be prioritised by searches for extrasolar biospheres.
Read the full abstract ▾
Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph
Misalignment from kicks: the impact of particle interactions on ultra-light dark matter
Clare Burrage and Sergio Sevillano Muñoz
Oscillating ultra-light scalar fields are a natural explanation for the dark matter in our universe, as long as a mechanism, often called a misalignment mechanism, exists to explain the amplitude of the scalar oscillations. If the dark matter scalar couples to the Standard Model, then the dynamics of ordinary matter can influence the behaviour of dark matter in the early universe. In this work we show how this changes the expected value of the scalar field and the resulting amplitude of late time scalar oscillations, and therefore the abundance of dark matter at late times. For dark matter scalars that interact quadratically with Standard Model fields we derive estimates of the size of this effect as a function of the strength of the coupling, and for
axion-like fields we show that interactions with dark sector matter can temporarily destabilize the field, leading to large field displacements.
Read the full abstract ▾
Astrophysics of Galaxies
Formation and disruption of wide binaries in star clusters revealed by N-body simulations
Abylay Bissekenov, Xiaoying Pang, Rainer Spurzem et al. (+3 more)
Wide (soft) binaries are expected to be rapidly disrupted in dense
stellar environments, yet they are observed in both the
Galactic field and open clusters (OCs). In this paper, we investigate the formation and disruption of wide binaries in
star clusters using direct N-body simulations. We perform simulations containing 10,000 objects with varying binary fractions and initial bulk rotation to give an in-depth look into the dynamical
evolution of wide binaries in
star clusters. We find that wide binaries dominate early disruption and formation processes during the initial high-density phase of cluster
evolution. We propose two semi-analytical models to reproduce the
evolution of the wide-binary population in simulations. The exponential model consists of an early, rapid-disruption phase with a time less than 10 Myr, driven by frequent encounters at high density, and a longer, relaxation-driven phase between 200 and 300 Myr. The broken power-law model provides break timescales when the decrease of wide binaries slows down during the early and long-term disruption. All timescales from both models agree with each other and decrease with increasing
stellar density induced by high
primordial binary fraction and cluster rotation. Wide binary disruption is mostly responsible for the early decline in the total binary fraction of the cluster. Such disruption leads to the decrease of radial binary fraction toward the cluster center until 500 Myr. Our results suggest low-density OCs or
stellar groups younger than 10 Myr as the optimal environments for detecting wide binaries and provide a physical framework for understanding their contribution to the
Galactic field population.
Read the full abstract ▾
All authors Abylay Bissekenov, Xiaoying Pang, Rainer Spurzem, Bekdaulet Shukirgaliyev, Mukhagali Kalambay, Peter Berczik
Earth and Planetary Astrophysics
Large Dust Grains and a Possible Dust Trap in the Polar Circumbinary Disc of HD 98800B
Álvaro Ribas, Thomas Lack, Francesco Zagaria et al. (+6 more)
HD 98800 is a nearby hierarchical quadruple system comprising two binaries orbiting each other. Surprisingly, despite its $\sim$ 10 Myr age and dynamic environment, the Ba-Bb component is surrounded by a compact gas-rich disc in a polar configuration. Previous millimetre continuum observations of this disc found a low millimetre spectral index ($\alpha \sim$ 2.1 up to 9 mm), potentially arising from large
dust grains, optically thick emission, or both. Furthermore, the interpretation was complicated by emission mechanisms other than
dust thermal continuum at longer wavelengths. We present new observations of this system with the Very Large Array (VLA) at 6.8 mm and 3 cm, providing crucial additional sampling of the emission at millimetre/centimetre wavelengths. By combining these with ancillary data, we derive a
dust spectral index $\alpha_{\rm dust} <$ 3 for wavelengths $\le$ 1 cm. Our modeling suggests that the emission is optically thick at short millimetre wavelengths ($\lambda \le$ 3 mm) and it becomes at least partially optically thin for the VLA observations. The shallow spectral index thus indicates the existence of large grains in the disc. We also identify gyro-synchrotron emission from the A and B components at $\lambda \gtrsim $ 3 cm. The VLA images also reveal an azimuthal asymmetry at 6.8 mm and 8.8 mm, which is not present in high-resolution ALMA 1.3 mm data. After ruling out
geometric and illumination effects, we interpret this asymmetry as a local
dust overdensity, possibly induced by a
vortex or a relic of the previous passage of the A component.
Read the full abstract ▾
All authors Álvaro Ribas, Thomas Lack, Francesco Zagaria, Enrique Macías, Sean M. Andrews, Amelia Bayo, Cathie J. Clarke, Nicolás Cuello, Catherine C. Espaillat
Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc
The Depletion of Collisionless Dark Matter Spikes
Charlie Sharpe, Yonadav Barry Ginat, Thomas F. M. Spieksma et al. (+2 more)
Dense concentrations of dark matter surrounding black holes provide a compelling opportunity to probe the nature of dark matter. In the classic Gondolo–Silk model, the adiabatic growth of a massive black hole in a dark matter cusp produces a steep density spike ($\rho \propto r^{-7/3}$), potentially inducing measurable gravitational-wave dephasings in intermediate and extreme mass-ratio inspirals (IMRIs/EMRIs). We challenge this paradigm by considering a collisionless dark matter spike embedded in a realistic
nuclear star cluster. Using Fokker–Planck models of isotropic
nuclear clusters, we show that mass segregation in a multi-mass
stellar cusp accelerates relaxation relative to single-mass models, thereby driving the dark matter to the lower density $r^{-3/2}$ Bahcall–Wolf profile within 1 Gyr. In the inner regions, where the Fokker–Planck description breaks down, we model strong triple interactions between dark matter particles and EMRIs using post-Newtonian 3-body simulations. We show that EMRIs eject dark matter particles via gravitational slingshots, depleting the inner spike over a few Gyr. Because EMRI number densities are too low to drive two-body relaxation, and replenishment by DM self-relaxation is negligible, this depletion is irreversible. While the extent of EMRI-induced DM depletion depends on the EMRI rate and mass, we find reductions in densities by several orders of magnitude. As a result, the dark-matter-induced dephasings for EMRIs may fall below the LISA detectability threshold for massive black holes at $z = 3$ (2.14 Gyr) with masses $\lesssim 10^{5}\,M_\odot$ (for a low $\mathcal{O}(10) \, \mathrm{Gyr}^{-1}$ EMRI rate), extending to $\lesssim 10^6\,M_\odot$ for more realistic rates of $\mathcal{O}(100 - 300)\,$Gyr$^{-1}$. Our findings substantially reduce the parameter space over which massive black holes can host detectable collisionless dark matter spikes.
Read the full abstract ▾
All authors Charlie Sharpe, Yonadav Barry Ginat, Thomas F. M. Spieksma, Alexander Heger, Bence Kocsis
Astrophysics of Galaxies
AGN Fueling and Radio Jet Evolution in the Galaxy Group NGC 5044 revealed by VLBA HI Absorption and Proper-Motion Radio Observations
Francesco Ubertosi, Ewan O'Sullivan, Gerrit Schellenberger et al. (+8 more)
The role of cooling gas in triggering active
galactic nucleus (AGN) feedback in the centers of
galaxy groups and clusters remains a key open question. NGC 5044, the X-ray brightest
galaxy group, hosts the largest known reservoir of molecular gas among cool-core groups and exhibits multiple AGN outbursts, making it an ideal system to study AGN feeding. We present new multi-frequency Very Long Baseline Array (VLBA) observations of NGC 5044 at 1.4 GHz, 4.9 GHz, and 8.4 GHz, combining continuum imaging with HI spectroscopy. At 1.4 GHz, we recovered the previously known symmetric northeast-southwest jets extending for 5.5 pc each, along with evidence for previously undetected, more extended faint emission aligned with the older, kpc-scale outbursts. Comparison of 4.9 GHz and 8.4 GHz data from 2020 and 2024 reveals clear outward proper motion of jet components, yielding an average expansion speed of $(0.10\pm0.02)\,c$ and implying a dynamical age of $\sim$180 yr for the ejection of the parsec-scale jet components. The jet width profile suggests a transition from
parabolic to conical collimation at a few $\times 10^{4}$ Schwarzschild radii. We detect a narrow, redshifted HI absorption line at $+264\,\mathrm{km\,s^{-1}}$ against the VLBA core, tracing a compact, cold atomic cloud within $\sim$10-20 pc of the AGN. The close velocity correspondence with previously detected CO and HI absorption features in ALMA and MeerKAT data, respectively, demonstrates that cold atomic and molecular gas coexists in infalling clouds at parsec scales. Overall, these results provide an unprecedented high angular resolution view of AGN cycling, jet growth, and feeding in a
galaxy group environment.
Read the full abstract ▾
All authors Francesco Ubertosi, Ewan O'Sullivan, Gerrit Schellenberger, William Forman, Kamlesh Rajpurohit, Simona Giacintucci, Tiziana Venturi, Jan Vrtilek, Laurence P. David, Preeti Kharb, Christine Jones
Astrophysics of Galaxies
Something Bright at the Edge of Everything: A Uniquely JWST-Dark Radio Source in COSMOS
Mingyu Li
For decades, astronomers have been searching for bright
radio sources deep into the epoch of reionization (EoR). The most distant, powerful
radio sources are expected to reside in heavily
dust-obscured
galaxies, exceedingly faint at optical and infrared wavelengths. Motivated by this, I systematically cross-match
radio and JWST source catalogs in the COSMOS field and identify a uniquely JWST-dark
radio source: the only object undetected in every JWST band, yet clearly detected in
radio data from LOFAR 144 MHz to the VLA 3 GHz. The source is only marginally resolved and shows a steep, unbroken
radio spectrum, while remaining undetected in all available HST, JWST, Chandra, Herschel, and ALMA imaging. It may represent an extremely
dust-obscured
radio-loud source at
cosmic dawn, or alternatively a detached
radio lobe whose host
galaxy lies elsewhere. In either case, it highlights the new discovery space at the intersection of deep
radio surveys and JWST imaging.
Read the full abstract ▾
Astrophysics of Galaxies
Enhanced Multiphase Circumgalactic Medium and Gas Cycling in Galaxy Mergers
Maolan Yang, Suoqing Ji, Robert Feldmann et al. (+9 more)
We investigate the impact of
galaxy mergers on the circumgalactic medium (CGM) using the FIREbox cosmological hydrodynamic simulation. By comparing matched samples of merging and isolated
galaxies with
stellar masses $M_\star \sim 10^{10}$–$10^{11} M_{\odot}$ at $z=0$ and mass ratio of merging
galaxies larger than $1:10$, we find that mergers significantly alter CGM properties. Merging systems exhibit enhanced radiative cooling, leading to shorter cooling times than free-fall times across large CGM volumes. This results in amplified multiphase structure and increased cool/cold gas content ($T \sim 10^4K$) compared to isolated
galaxies. Both inflow and
outflow mass fluxes are elevated by at least $\sim$1 dex in mergers across all temperature phases, with cool gas primarily generated in-situ via radiative cooling rather than from pre-existing streams. Gas cycling analysis reveals that mergers fundamentally accelerate CGM processing, amplifying the effective transfer rate from cold/cool
cosmic inflow to
galaxy inflow by factors of $\sim 30$, through rapid cycling of inflowing gas through intermediate CGM phases, efficiently fueling the ISM and
star formation. The enhanced cool gas content in mergers produces elevated column densities for low- and intermediate-temperature ion species in the inner CGM, while high-temperature ones remain largely unaffected.
Read the full abstract ▾
All authors Maolan Yang, Suoqing Ji, Robert Feldmann, Feng Yuan, Jorge Moreno, Taotao Fang, Coral Wheeler, Luigi Bassini, Jing Wang, Jonathan Stern, Claude-André Faucher-Giguère, Dušan Kereš
Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph
James M. Cline, Gonzalo Herrera and Jean-Samuel Roux
Active
neutrinos in standard cosmology were ruled out as a dark matter candidate in the 1980's. The reason is twofold: they are too light to account for the observed energy density of dark matter in the Universe, and their relativistic nature would spoil structure formation. In this note we suggest that an enhanced density of cold Standard Model active
neutrinos today could behave effectively as dark matter, avoiding constraints from recombination and structure formation. Such an enhancement could be produced, for instance, by late-time decays of a light scalar field that is not in thermal
equilibrium with the
plasma. This mechanism is testable through the detection of the
Cosmic Neutrino Background (C$\nu$B), which could have an average cosmological energy density a factor of $\sim 100-200$ times larger than expected in $\Lambda$CDM. The postulated light neutrinophilic scalar field may be observable, with Yukawa couplings in the range $y \sim 5 \times 10^{-16}-10^{-12}$. A scenario preferred by structure formation constraints is that the scalar is a Majoron, and the
neutrinos have an inverted mass hierarchy.
Read the full abstract ▾
High Energy Astrophysical Phenomena
Numerical calculations of neutron star mountains supported by crustal lattice pressure
T. J. Hutchins and D. I. Jones
Gravitational waves may set the
spin frequencies of
neutron stars in low-mass X-ray binaries (LMXBs). One mechanism for facilitating such emission is the formation of a mass asymmetry - or `mountain' - supported by elastic strains driven by thermal gradients. Most studies have focused either on the origin of the elastic strains or the temperature asymmetry in isolation, and have not considered the entire formation process. In previous work, we showed that anisotropic heat transport in magnetised accreting
neutron stars can source a significant temperature asymmetry, and made rough estimates that suggested temperature-induced perturbations in the pressure supplied by the crustal
lattice may be competitive with the widely known model of temperature-induced capture-layer shifts. In this paper we carry out detailed calculations to properly explore this scenario. We self-consistently calculate the temperature asymmetries, the perturbations in crustal
lattice pressure, and the mass asymmetries within a single framework. For the first time, we make use of the set of realistic equations of state from the Brussels-Montreal
nuclear energy-density functionals BSk19, BSk20, and BSk21 which describe all regions of accreting
neutron stars in a thermodynamically consistent, unified way. We find these mountains are too small to dictate the
spin-
equilibrium of LMXBs, and estimate the level of gravitational wave emission they produce.
Read the full abstract ▾
Astrophysics of Galaxies
MUSE-DARK-II: 3D morpho-kinematic modelling of lensed galaxies. Tully-Fisher relation of $z \sim 1$ star-forming galaxies
Alexandre Jeanneau, Johan Richard, Nicolas F. Bouché et al. (+5 more)
In a series of papers on lensed kinematics, we seek to combine the sensitivity of 3D forward modelling to low signal-to-noise ratio outskirts with the enhanced spatial resolution of cluster
lensing. In this first paper, we (i) present and validate our methodology, which directly constrains the source parameters by incorporating
lensing deflections into the $\texttt{GalPaK}^\texttt{3D}$ forward-modelling
algorithm, and (ii) investigate the
evolution of the
stellar-mass and baryonic-mass Tully-Fisher relations (sTFR and bTFR) since $z \sim 1$. We define a robust sample of strongly lensed
star-forming
galaxies (SFGs) from the MUSE
Lensing Cluster survey, spanning magnifications $\mu = 1.4 - 12.4$ and
stellar masses $M_\star = 10^{8.1} - 10^{10.3} M_\odot$. Using a series of mock
galaxies, we find that our method is significantly more reliable at recovering morpho-kinematic properties than approaches that ignore differential magnification, even for relatively modest magnifications ($\mu < 6$). Restricting the analysis to 95 rotationally supported SFGs with well-constrained velocities, we find a significant
evolution of the sTFR zero-point ($\Delta b^\mathrm{sTFR} = -0.42^{+0.05}_{-0.05}~\mathrm{dex}$ in
stellar mass) but no detectable
evolution of the bTFR zero-point ($\Delta b^\mathrm{bTFR} = 0.00^{+0.06}_{-0.06}~\mathrm{dex}$ in baryonic mass) relative to $z \approx 0$. Our results are consistent with a mild
evolution of the
stellar-to-
halo mass ratio and support the view that the sTFR has evolved only weakly over the past $\sim 8$ Gyr, aside from shifts driven by the
redshift dependence of
halo-defining quantities such as the critical density and overdensity. The absence of detectable
evolution in the bTFR zero-point suggests that the increasing contribution of cold gas mass at higher
redshift fully compensates the
evolution observed in the
stellar component alone. [abridged]
Read the full abstract ▾
All authors Alexandre Jeanneau, Johan Richard, Nicolas F. Bouché, Davor Krajnović, Bianca-Iulia Ciocan, Jonathan Freundlich, Benoît Epinat, Thierry Contini
Astrophysics of Galaxies
The CAVITY project. The spatially resolved SFR of galaxies in voids
Ana M. Conrado, Rubén García-Benito, Rosa M. González Delgado et al. (+24 more)
The mass in the Universe is distributed non-uniformly, originating the Large Scale Structure (LSS), characterised by clusters, filaments, walls and voids.
Galaxies in voids are bluer, later type, less massive, and have slower
evolution than
galaxies in denser environments. The effect of the void environment on properties such as
star formation rate (SFR) is still under discussion. We tackle this by estimating spatially-resolved SFR from extinction-corrected Halpha luminosities of 220 void
galaxies from the CAVITY survey. These observations consist of optical integral field unit data cubes from the PMAS/PPaK spectrograph at Calar Alto Observatory. We measure the continuum-subtracted emission lines to obtain maps of SFR, specific
star formation rate (sSFR) and extinction. We assess global properties and radial profiles up to 2 half-light radii. We compare with
galaxies in filaments and walls from the CALIFA survey using the same methodology, building a control sample matched in morphology and
stellar mass. We find no significant differences in SFR and sSFR, although void
galaxies tend to have larger SFR, especially for early spirals. This effect is present for Sa
galaxies at all galactocentric distances, and in the outer parts of late-type spirals, evidencing slower transition to quiescence and less evolved discs. Void late-type
galaxies have lower extinction. Using extinction normalised by
stellar mass surface density as a proxy for gas mass fraction, we find it larger for void early spirals, especially in outer regions. This indicates the effect of the void environment on the transition from
star forming to passive.
Read the full abstract ▾
All authors Ana M. Conrado, Rubén García-Benito, Rosa M. González Delgado, Bahar Bidaran, Hélène M. Courtois, Salvador Duarte Puertas, Daniel Espada, Andoni Jiménez, Ignacio del Moral-Castro, Isabel Pérez, Tomás Ruiz-Lara, Laura Sánchez-Menguiano, Gloria Torres-Ríos, Simon Verley, María Argudo-Fernández, Simon B. De Daniloff, Estrella Florido, Yllari K. González-Koda, Alejandra Z. Lugo-Aranda, Javier Román, Smitha Subramanian, Pedro Villalba-González, Manuel Alcázar-Laynez, Mónica Hernández-Sánchez, Mónica Rodríguez Martínez, Paulo Vásquez-Bustos, Martin Blazek
Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph
Quasi-linear theory of fast flavor instabilities in homogeneous environments
Damiano F. G. Fiorillo and Georg G. Raffelt
Dense
neutrino plasmas can develop instabilities that drive collisionless
flavor exchange, equivalent to the emission of flavomons, the quanta of
flavor waves. We treat these waves, for the first time, as independent linear degrees of freedom and develop a quasi-linear theory (QLT), including backreaction on the
neutrino distribution and nonresonant
neutrino–flavomon interactions, while neglecting wave–wave processes. In a homogeneous, axisymmetric model, the saturated
neutrino and flavomon distributions agree closely with periodic-box solutions of the original
quantum kinetic equation. These results support the use of QLT, well established in
plasma physics, to bypass nonlinear small-scale effects that challenge direct simulations.
Read the full abstract ▾
Earth and Planetary Astrophysics
Gaia DR3 IDs for TESS Input Catalog Targets
Kevin K. Hardegree-Ullman, Melanie Swain, Jessie L. Christiansen et al. (+6 more)
The TESS Input Catalog (TIC) was built on
Gaia Data Release 2 (DR2). To date, there has not been an update to the TIC to incorporate
Gaia Data Release 3 (DR3) IDs. In this Research Note, we outline how we cross-matched the TIC with
Gaia DR3 IDs, its immediate applications to
exoplanet research, and lessons learned when dealing with such large data sets. A full TIC/
Gaia DR3 cross-match table is available for download on the
Exoplanet Follow-up Observing Program (ExoFOP) website, and a Jupyter Notebook with instructions to reproduce the table is available on GitHub.
Read the full abstract ▾
All authors Kevin K. Hardegree-Ullman, Melanie Swain, Jessie L. Christiansen, Emily A. Gilbert, Marcy Harbut, Aurora Y. Kesseli, Michael B. Lund, Meca Lynn, Julian C. van Eyken
Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph
Boltzmann Equation Solver for Thermalization
Jong-Hyun Yoon
We present BEST (Boltzmann Equation Solver for Thermalization), a Python framework for solving the momentum-resolved Boltzmann equation for arbitrary $n_{\rm in} \to n_{\rm out}$ scattering processes. The collision integral is evaluated directly in $3(n_{\rm total}-2)$ dimensions using the VEGAS adaptive Monte Carlo
algorithm with vectorized batch evaluation. Momentum conservation is enforced exactly by expressing one particle's momentum through the constraint, while energy conservation is imposed via a narrow Gaussian representation of the delta function. We identify a subtlety in the construction of the collision integral for processes with unequal initial and final multiplicities ($n_{\rm in} \neq n_{\rm out}$) involving identical particles: the full collision rate requires separate evaluation with the observed momentum pinned to each side of the reaction, weighted by the respective particle multiplicities. Failure to account for this leads to systematic violation of energy conservation. The code supports massive particles with time-dependent masses, Bose-Einstein and
Fermi-Dirac
quantum statistics, multiple coupled species, cosmological expansion with comoving momenta, and both Euler and Heun time integration. Parallelization is achieved by distributing independent momentum grid points across MPI ranks, yielding near-linear scaling to hundreds of cores. We validate the Monte Carlo results against a semi-analytical $2 \to 2$ collision integral with exact energy conservation, following the phase-space reduction of Ala-Mattinen et al. As a demonstration, we study thermalization of a massive scalar field through a $2 \leftrightarrow 3$ number-changing process and show that energy conservation is restored only when all identical-particle contributions are correctly summed. The code is publicly available at https://github.com/best-hep/best.
Read the full abstract ▾
Instrumentation and Methods for Astrophysics
Declarative bespoke modelling: A new approach
DBM Collaboration: David Komanek, Vaclav Pavlík, Santiago Jimenez et al. (+1 more)
Modern numerical models are increasingly complex, opaque, and computationally expensive, yet frequently fail to predict even qualitative features of observed phenomena. We propose a new paradigm, Declarative Bespoke Modelling, in which the modeller explicitly declares the relationship between model inputs and outputs. We demonstrate that this approach achieves perfect predictive accuracy, unconditional numerical stability, and complete interpretability. It represents a natural endpoint of contemporary modelling practice and near-zero CO2 emission.
Read the full abstract ▾
All authors DBM Collaboration: David Komanek, Vaclav Pavlík, Santiago Jimenez, Rhys Taylor
Cosmology and Nongalactic Astrophysics
From photometric surveys to HI intensity mapping: Improving constraints on magnification biases while testing gravity
Tiago Sinde and José Fonseca
The observed large-scale structure of the Universe is not a direct measure of the underlying distribution of matter. These observations are subtly distorted by gravitational
lensing effects, which leave imprints on the statistical distribution of
galaxies and offer a powerful test of general relativity. In this work, we investigate whether HI intensity mapping from current and forthcoming surveys can improve constraints on magnification
lensing obtained from photometric
galaxy surveys. In particular, we investigate whether one can jointly constrain the magnification bias parameters $s^\mathrm{G}(z)$ and the amplitude of the Weyl potential, which we parametrise as $\beta$. We employ a Fisher
matrix formalism in order to estimate future constraints on the magnification biases and $\beta$. We forecast constraints for three photometric surveys (DES-like, LSST-like, Euclid-like) individually and together with two HI intensity mapping surveys (MeerKLASS, SKAO). We apply the multi-tracer technique by combining each
galaxy survey with each HI survey, exploiting the combined constraining in the overlapping sky area. The multi-tracer approach dramatically improves constraints on $\beta$ by factors of 18 to 50, depending on the surveys considered. For $s^\mathrm{G}(z)$, improvements can be marginal or by factors of 2 to 4. We also verify that $\beta$ and $s^\mathrm{G}(z)$ can be constrained simultaneously as the cross-correlations between tracers break the degeneracies among them. We conclude that the multi-tracer combination of photometric
galaxy surveys and HI intensity mapping surveys enables high-precision measurements of both $s^\mathrm{G}(z)$ and $\beta$. This opens an additional pathway to constrain $\Phi+\Psi$ and test the validity of general relativity on cosmological scales.
Read the full abstract ▾