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Physics Astrophysics

astro-ph Watch Astrophysics

Wednesday 14 January

High Energy Astrophysical Phenomena

Stellar-wind Fueled Accretion onto Sagittarius A* in the Presence of a Nuclear Star Cluster

Edward Skrabacz, Lena Murchikova, Sean M. Ressler et al. (+2 more)

The Milky Way's Galactic Center hosts the black hole Sagittarius A* (Sgr A*), which provides us with a close-up view into supermassive black hole accretion and feedback. Recent works have shown that the winds from $\sim 30$ Wolf-Rayet (WR) stars orbiting Sgr A* at about 4 arcsec are important contributors to feeding the supermassive black hole. A nuclear star cluster (NSC) with a mass of several $10^6 \, \text{M}_\odot$, of which $10^6 \, \text{M}_\odot$ is within 1 pc, also surrounds Sgr A*. The NSC contributes to the gravitational potential in the Galactic Center, affecting the orbits of the WR stars and their stellar winds. In this work, we examine the effects that the NSC has on the accretion of these stellar winds onto Sgr A* which have previously been neglected. We find that, on the parsec scale, the effect from the gravitational potential of the NSC is negligible on the wind-fed accretion flow, validating the existing simulations used in the literature.
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All authors Edward Skrabacz, Lena Murchikova, Sean M. Ressler, Asad Ukani, Siddhant Solanki

Astrophysics of Galaxies

HR-GO II: chemical abundances of low-$E$ retrograde dynamically-tagged-groups: Revealing Thamnos as a very metal-poor substructure

Renjing Xie, Zhen Yuan, Haining Li et al. (+12 more)

Milky Way halo substructures identified in dynamical space are known to suffer from contamination from the Milky Way in-situ stars, which makes their accreted origins uncertain. We present detailed chemical abundances of 35 stars belonging to two sets of dynamically tagged groups, Rg8 and Rg9, to investigate their accreted nature. Both groups are composed of stars with low orbital energy and very retrograde orbits. We find that Rg8 and Rg9 are chemically indistinguishable across all elements, from C to Eu, strongly indicating that they belong to the same structure. The iron-abundance distribution of this low-$E$ retrograde group has a prominent peak at [Fe/H] $\approx-2.1$, revealing that its main population is very metal-poor, and a secondary peak at [Fe/H] $\approx-1.5$, very likely due to contamination from Milky Way in-situ stars. These groups also heavily overlap with the Thamnos substructure in dynamical space, and we thus use them to investigate the chemical properties of Thamnos. The dominant, low-metallicity population provides strong evidence for the ex-situ origin of Thamnos, as well as its very metal-poor nature. We do not see any evidence of an $\alpha$ knee in our sample, which is consistent with previous studies. Comparison with the Cetus-Palca stream in the chemical space shows similar abundance distributions, and thus it suggests that the Thamnos progenitor dwarf galaxy had a truncated star formation history due to its early merger with the Milky Way.
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All authors Renjing Xie, Zhen Yuan, Haining Li, Tadafumi Matsuno, Nicolas F. Martin, Ruizhi Zhang, Zhiqiang Yan, Federico Sestito, Guillaume F. Thomas, Projjwal Banerjee, Ruizheng Jiang, Linda Lombardo, David S. Aguado, Kohei Hattori, Gang Zhao

Astrophysics of Galaxies

The influence of magnetic fields in Cloud-Cloud Collisions

Theotokis Georgatos and Anthony P. Whitworth

Cloud-cloud collisions are expected to trigger star formation by compressing gas into dense, gravitationally unstable regions. However, the role of magnetic fields in this process is unclear. We use SPH to model head-on collisions between two uniform density clouds, each with mass $500 \,$M$_{\odot}$, initial radius 2 pc, and embedded in a uniform magnetic field parallel to the collision velocity. As in the nonmagnetic case, the resulting shock-compressed layer fragments into a network of filaments. If the collision is sufficiently slow, the filaments are dragged into radial orientations by non-homologous gravitational contraction, resulting in a $\textit{Hub Filament}$ morphology, which spawns a centrally concentrated monolithic cluster with a broad mass function shaped by competitive accretion and dynamical ejections. If the collision is faster, a $\textit{Spiders Web}$ of intersecting filaments forms, and star-systems condense out in small subclusters, often at the filament intersections; due to their smaller mass reservoirs, and the lower probability of dynamical ejection, the mass function of star-systems formed in these subclusters is narrower. Magnetic fields affect this dichotomy quantitatively by delaying collapse and fragmentation. As a result, the velocity threshold separating $\textit{Hub Filament}$ and $\textit{Spiders Web}$ morphologies is shifted upward in magnetised runs, thereby enlarging the parameter space in which $\textit{Hub Filament}$ morphologies form, and enhancing the likelihood of producing centrally concentrated clusters. Consequently, magnetic fields regulate both the morphology and timing of star formation in cloud-cloud collisions: they broaden filaments, delay the onset of star formation, and promote the formation of $\textit{Hub Filament}$ morphologies, monolithic clusters and high-mass star-systems.
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Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph

The Cosmic Neutrino Background is within Reach of Future Neutrino Telescopes

Gonzalo Herrera, Shunsaku Horiuchi, Xiaolin Qi et al. (+1 more)

The cosmic neutrino background (C$\nu$B) can be boosted to high energies due to scatterings with energetic cosmic rays (CRs) across cosmological scales. Previous calculations focused on neutral current incoherent and coherent elastic scatterings of cosmic-ray protons off relic neutrinos. However, charged current interactions and deep inelastic scatterings are also expected to occur, which enhances the boosted relic neutrino fluxes on Earth. Here, we compute the total diffuse boosted cosmic neutrino background (DBC$\nu$B) arising from CRs at all redshifts in the Universe, accounting for neutral current and charged current elastic and deep inelastic scatterings. We find that IceCube already places an upper limit on the cosmic neutrino background overdensity in cosmological scales of ~$\mathcal{O}(100-1000)$ at $E_{\nu}=10^{10}$ GeV, for a lightest neutrino mass of $m_{\nu} \gtrsim 0.1$ eV. We further show that IceCube-Gen2 could test $\mathcal{O}(1-10)$ C$\nu$B overdensities, and the combination of $10$ future neutrino telescopes with similar sensitivity would allow us to test the $\Lambda$CDM expected C$\nu$B density for a lightest neutrino mass compatible with the KATRIN bound.
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All authors Gonzalo Herrera, Shunsaku Horiuchi, Xiaolin Qi, Ian M. Shoemaker

Astrophysics of Galaxies

Growing in number, passive in nature: tracing the evolution of the most massive quiescent galaxies since z ~ 0.8 with BOSS and DESI

F. R. Ditrani, M. Fossati, M. Longhetti et al. (+5 more)

Luminous Red Galaxies (LRGs) are among the most massive galaxies at any epoch, and lack ongoing star formation. As systems hosting most of the baryonic mass in the local Universe, they preserve imprints of the quenching mechanisms in the early Universe. We exploited the large BOSS and DESI spectroscopic datasets to perform the first homogeneous and continuous mapping of the evolution of stellar population properties of a complete sample of the most massive LRGs ($\log (M_*/\mathrm{M_\odot})> 11.5$) at 0.15 < z < 0.8. By consistently fitting the same spectral indices at all redshifts, we measured trends of [Fe/H], [alpha/Fe], and light-weighted age as a function of redshift. These galaxies exhibit a passive light-weighted age evolution and flat [Fe/H] and [alpha/Fe] trends towards lower redshift, indicating genuinely passive evolution. These trends are robust against the choice of stellar population models and analysis assumptions, and they support the predictions from IllustrisTNG, which predict negligible chemical evolution for the most massive quenched systems at z < 0.8. Our results suggest that, despite nearly 5 Gyr of cosmic time and a 3-4x increase in number density, the stellar population properties of massive quiescent galaxies remain essentially unchanged since z ~ 0.8. This shows a negligible progenitor bias below z ~ 0.8, and a genuinely passive evolution. Newly added systems after $z \sim 0.8$ were already largely quenched and chemically mature, while subsequent evolution was dominated by dry mergers without altering the bulk of the stellar populations.
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All authors F. R. Ditrani, M. Fossati, M. Longhetti, F. La Barbera, A. Iovino, C. Maraston, D. Thomas, D. Bevacqua

High Energy Astrophysical Phenomena

New Hard X-Ray and Multiwavelength Study of the PeVatron Candidate PWN G0.9+0.1 in the Galactic Center Region

Giulia Brunelli, Kaya Mori, Jaegeun Park et al. (+12 more)

We present a new X-ray study and multiwavelength spectral energy distribution (SED) modeling of the young pulsar wind nebula (PWN) powered by the energetic pulsar PSR J1747-2809, inside the composite supernova remnant (SNR) G0.9+0.1, located in the Galactic Center region. The source is detected by NuSTAR up to 30 keV with evidence for the synchrotron burnoff effect in the changing spatial morphology with increasing energy. The broadband 2-30 keV spectrum of PWN G0.9+0.1 is modeled by a single power law with photon index $\Gamma=2.11\pm0.07$. We combined the new X-ray data with the multiwavelength observations in radio, GeV, and TeV gamma rays and modeled the SED, applying a one-zone and a multi-zone leptonic model. The comparison of the models is successful, as we obtained physically compatible results in the two cases. Through the one-zone model, we constrain the age of the system to $\sim2.2$ kyr, as well as reproduce the observed PWN and SNR radio sizes. In both the one-zone and multi-zone leptonic models, the electron injection spectrum is well-described by a single power law with spectral index $p \sim 2.6$ and a maximum electron energy of $\sim2$ PeV, suggesting the source could be a leptonic PeVatron candidate. We estimate the average magnetic field to be $B_{\rm PWN} \sim 20\ \mu$G. We also report the serendipitous NuSTAR detection of renewed X-ray activity from the very faint X-ray transient XMMU J174716.1-281048 and characterize its spectrum.
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All authors Giulia Brunelli, Kaya Mori, Jaegeun Park, Jordan Eagle, Moaz Abdelmaguid, Melania Nynka, Hongjun An, Aya Bamba, Joseph D. Gelfand, Gabriele Ponti, Samar Safi-Harb, Vito Sguera, Cristian Vignali, Jooyun Woo, Roberta Zanin

Cosmology and Nongalactic Astrophysics · Cross-listed from hep-th

Microscopic Description of Critical Bubbles

Carlos Hoyos, David Mateos, Wilke van der Schee et al. (+1 more)

First-order phase transitions occur through the nucleation of critical bubbles of the stable phase within the metastable phase. Using holography, we present a fully microscopic description of these bubbles in a strongly coupled, four-dimensional gauge theory at finite temperature. In the gravitational dual, these bubbles correspond to static, inhomogeneous and unstable black-brane solutions with a localized deformation on the horizon. We construct these solutions across the entire metastable branch and compute the surface tension and the nucleation rate. We then compare these microscopic results with those obtained from a two-derivative effective action for the order parameter in two different scenarios. When the effective action is derived from the microscopic theory via holography, we find remarkable agreement. However, when the effective action is constrained only by the equation of state and dimensional analysis, significant discrepancies emerge. These discrepancies can be resolved if an additional constraint related to the surface tension is imposed.
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All authors Carlos Hoyos, David Mateos, Wilke van der Schee, Javier G. Subils

Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph

Classical equipartition dynamics between axions and non-Abelian gauge fields

Kim V. Berghaus, Adrien Florio, M. Laine et al. (+1 more)

Motivated by axion-like inflation and its warm embedding within the Standard Model, we study the early stages of the energy transfer between an axion condensate and an SU(2) gauge ensemble, by employing non-linear classical real-time lattice simulations. The discretized equations of motion are worked out, elaborating on Gauss constraints. A numerical solution is implemented on the CosmoLattice platform. Adopting a quadratic potential, and omitting universe expansion, we establish initial exponential growth of the low-momentum gauge modes; damping of axion oscillations after some delay; and subsequent energy equipartition between axion and gauge ensembles. A clear difference between the SU(2) and U(1) dynamics is observed, likely associated with non-Abelian self-interactions. We elaborate on what this implies for the possible thermalization of the SU(2) ensemble.
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All authors Kim V. Berghaus, Adrien Florio, M. Laine, Franz R. Sattler

Astrophysics of Galaxies

Breathless BEARS: [O$_{\rm \,III}$] 88$\mu$m Emission of Dusty Star-Forming Galaxies at $z = 3-4$

T. J. L. C. Bakx, Hiddo S. B. Algera, Prachi Prajapati et al. (+13 more)

We present [O$_{\rm \,III}$] 88$\mu$m observations towards four ${\it Herschel}$-selected dusty star-forming galaxies (DSFGs; log$_{10}$ $\mu$L$_{\rm IR}$/L$_{\odot}$ = 13.5 - 14 at $z = 2.9 - 4$) using the Atacama Compact Array (ACA) in Bands 9 and 10. We detect [O$_{\rm \,III}$] emission in all four targets at >3$\sigma$, finding line luminosity ratios ($L_{\rm [O_{\rm \,III}]}$ / L$_{\rm IR}$ = 10$^{-4.2}$ to 10$^{-3}$) similar to local spiral galaxies, and an order of magnitude lower when compared with local dwarf galaxies as well as high-redshift Lyman-break galaxies. Using the short-wavelength capabilities of the ACA, these observations bridge the populations of galaxies with [O$_{\rm \,III}$] emission at low redshift from space missions and at high redshift from ground-based studies. The difference in [O$_{\rm \,III}$] emission between these DSFGs and other high-redshift galaxies reflects their more evolved stellar populations (> 10 Myr), larger dust reservoirs (M$_{\rm dust}$ $\sim$ 10$^{9 - 11}$ M$_{\odot}$), metal-rich interstellar medium ($Z \sim 0.5 - 2$ Z$_{\odot}$), and likely weaker ionization radiation fields. Ancillary [C$_{\rm \,II}$] emission on two targets provide $L_{[{\rm O}_{\rm \,III}]} / L_{[{\rm C}_{\rm \,II}]}$ ratios at 0.3 - 0.9, suggesting that ionized gas represents a smaller fraction of the total gas reservoir in DSFGs, consistent with theoretical models of DSFGs as transitional systems between gas-rich, turbulent disks and more evolved, gas-poor galaxies. Expanding samples of DSFGs with [O$_{\rm \,III}$] emission will be key to place this heterogeneous, poorly-understood galactic phase in its astrophysical context.
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All authors T. J. L. C. Bakx, Hiddo S. B. Algera, Prachi Prajapati, George Bendo, Stefano Berta, Laura Bonavera, Pierre Cox, Joaquin González-Nuevo, Masato Hagimoto, Kevin Harrington, Matthew Lehnert, Stephen Serjeant, Pasquale Temi, Paul van der Werf, Chentao Yang, Gianfranco De Zotti

Astrophysics of Galaxies

The X-Ray Dot: Exotic Dust or a Late-Stage Little Red Dot?

Raphael E. Hviding, Anna de Graaff, Hanpu Liu et al. (+15 more)

JWST's "Little Red Dots" (LRDs) are increasingly interpreted as active galactic nuclei (AGN) obscured by dense thermalized gas rather than dust as evidenced by their X-ray weakness, blackbody-like continua, and Balmer line profiles. A key question is how LRDs connect to standard UV-luminous AGN and whether transitional phases exist and if they are observable. We present the "X-Ray Dot" (XRD), a compact source at $z=3.28$ observed by the NIRSpec WIDE GTO survey. The XRD exhibits LRD hallmarks: a blackbody-like ($T_{\rm eff} \simeq 6400\,$K) red continuum, a faint but blue rest-UV excess, falling mid-IR emission, and broad Balmer lines ($\rm FWHM \sim 2700-3200\,km\,s^{-1}$). Unlike LRDs, however, it is remarkably X-ray luminous ($L_\textrm{2$-$10$\,$keV} = 10^{44.18}\,$erg$\,$s$^{-1}$) and has a continuum inflection that is bluewards of the Balmer limit. We find that the red rest-optical and blue mid-IR continuum cannot be reproduced by standard dust-attenuated AGN models without invoking extremely steep extinction curves, nor can the weak mid-IR emission be reconciled with well-established X-ray–torus scaling relations. We therefore consider an alternative scenario: the XRD may be an LRD in transition, where the gas envelope dominates the optical continuum but optically thin sightlines allow X-rays to escape. The XRD may thus provide a physical link between LRDs and standard AGN, offering direct evidence that LRDs are powered by supermassive black holes and providing insight into their accretion properties.
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All authors Raphael E. Hviding, Anna de Graaff, Hanpu Liu, Andy D. Goulding, Yilun Ma, Jenny E. Greene, Leindert A. Boogaard, Andrew J. Bunker, Nikko J. Cleri, Marijn Franx, Michaela Hirschmann, Joel Leja, Rohan P. Naidu, Jorryt Matthee, David J. Setton, Hannah Übler, Giacomo Venturi, Bingjie Wang

Instrumentation and Methods for Astrophysics

CLiMB: A Domain-Informed Novelty Detection Clustering Framework for Galactic Archaeology and Scientific Discovery

Lorenzo Monti, Tatiana Muraveva, Brian Sheridan et al. (+4 more)

In data-driven scientific discovery, a challenge lies in classifying well-characterized phenomena while identifying novel anomalies. Current semi-supervised clustering algorithms do not always fully address this duality, often assuming that supervisory signals are globally representative. Consequently, methods often enforce rigid constraints that suppress unanticipated patterns or require a pre-specified number of clusters, rendering them ineffective for genuine novelty detection. To bridge this gap, we introduce CLiMB (CLustering in Multiphase Boundaries), a domain-informed framework decoupling the exploitation of prior knowledge from the exploration of unknown structures. Using a sequential two-phase approach, CLiMB first anchors known clusters using metric-adaptive constrained partitioning, and subsequently applies density-based clustering to residual data to reveal arbitrary topologies. We demonstrate this framework on RR Lyrae stars data from the Gaia Data Release 3. CLiMB attains an Adjusted Rand Index of 0.829 with 90% seed coverage in recovering known Milky Way substructures, outperforming heuristic and constraint-based baselines, which stagnate below 0.20. Furthermore, sensitivity analysis confirms CLiMB's superior data efficiency, showing monotonic improvement as knowledge increases. Finally, the framework successfully isolates three distinct dynamical features (Shiva, Shakti, and the Galactic Disk) in the unlabelled field, validating its potential for scientific discovery.
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All authors Lorenzo Monti, Tatiana Muraveva, Brian Sheridan, Davide Massari, Alessia Garofalo, Gisella Clementini, Umberto Michelucci

Instrumentation and Methods for Astrophysics

Habitable Worlds Observatory (HWO): Living Worlds Community Working Group: The Search for Life on Potentially Habitable Exoplanets

Giada Arney, Niki Parenteau, Natalie Hinkel et al. (+25 more)

The discovery of a biosphere on another planet would transform how we view ourselves, and our planet Earth, in relation to the rest of the cosmos. We now know Earth is one planet among eight circling our sun; our sun is part of a swirling galaxy of over one hundred billion other suns; and our galaxy is one of untold billions in the universe. While we do not yet know how many, if any, other biospheres exist on the countless worlds orbiting countless other suns, we stand at the precipice of a new era of discovery, enabled by powerful new facilities able to peer across the light years into the atmospheres of planets similar to our own. This article is an adaptation of a science case document (SCDD) developed for the NASA Astrophysics Flagship mission the Habitable Worlds Observatory (HWO) Science, Technology, and Architecture Review Team (START) Living Worlds Community Working Group.
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All authors Giada Arney, Niki Parenteau, Natalie Hinkel, Eric Mamajek, Joshua Krissansen-Totton, Stephanie Olson, Edward Schwieterman, Sara Walker, Kevin Fogarty, Ravi Kopparapu, Jacob Lustig-Yaeger, Mark Moussa, Sukrit Ranjan, Garima Singh, Clara Sousa-Silva, Ruslan Belikov, Maxwell Frissell, Samantha Gilbert-Janziek, Vincent Kofman, Natasha Latouf, Mary Anne Limbach, Rhonda Morgan, Christopher Stark, Armen Tokadjian, Anna Grace Ulses, Nicholas Wogan, Mike Wong, Amber Young

Instrumentation and Methods for Astrophysics · Cross-listed from physics.ins-det

DC response of an interferometer topology with an L-shaped cavity: a tabletop study

Junlang Li, Jiehong Huang, Xinyao Guo et al. (+11 more)

A new interferometer topology for kilohertz gravitational-wave detection was recently proposed in [Zhang et al. Phys. Rev. X 13, 021019 (2023)]. The design is based on an L-shaped optical cavity pumped through a Sagnac-like vortex. We report a tabletop experiment that characterizes the interferometer's optical response near DC. When the laser frequency is locked to the resonance of the L-shaped cavity, we observe that the cavity input coupler becomes effectively transparent, yielding a simple Michelson-like response. Moreover, the Sagnac vortex separates into upper and lower paths, which behave as two independent pumping paths driving the cavity. These observations are in agreement with theoretical predictions. Our results provide an intuitive physical picture of this interferometer topology and offer insight into its lock acquisition strategy.
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All authors Junlang Li, Jiehong Huang, Xinyao Guo, Haixing Miao, Yuchao Chen, Xiaoman Huang, Yuan Pan, Chenjie Zhou, Raffaele Flaminio, Jameson Graef Rollins, Bram Slagmolen, Fan Zhang, Teng Zhang, Mengyao Wang

High Energy Astrophysical Phenomena

Detection of Oscillations in a Type I X-Ray Burst of 4U 0614+091 with SVOM/ECLAIRs

Sébastien Le Stum, Floriane Cangemi, Alexis Coleiro et al. (+29 more)

On 2025 January 10, a thermonuclear (Type I) X-ray burst from the neutron star low-mass X-ray binary 4U~0614+091 was detected with the ECLAIRs instrument on board the SVOM mission. We present here a time-resolved spectroscopic analysis of the burst, along with the detection of burst oscillations within a 51-second interval during the decay phase. The oscillation frequency is measured to be $\nu = 413.674 \pm 0.002\,\mathrm{Hz}$, consistent with previous reports. However, we detect a significant downward frequency drift over the burst duration, characterized by $\dot{\nu} = (-4.7 \pm 0.3) \times 10^{-3}\,\mathrm{Hz\,s^{-1}}$. This frequency evolution is atypical compared to those observed in similar burst oscillation sources. We tentatively attribute the observed drift to a Doppler shift induced by orbital motion. Under this interpretation, the inferred orbital period must be shorter than 20 minutes, placing 4U~0614+091 among the most compact known low-mass X-ray binaries.
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All authors Sébastien Le Stum, Floriane Cangemi, Alexis Coleiro, Sébastien Guillot, Jérôme Chenevez, Philippe Bacon, Nicolas Bellemont, Laurent Bouchet, Tristan Bouchet, Cécile Cavet, Bertrand Cordier, Antoine Foisseau, Olivier Godet, Andrea Goldwurm, Xu-Hui Han, Cyril Lachaud, Zhaosheng Li, Hua-Li Li, Yu-Lei Qiu, Jérôme Rodriguez, Wen-Jun Tan, L. Tao, Lauryne Verwaerde, Chen-Wei Wang, Jing Wang, Jianyan Wei, Chao Wu, Wen-Jin Xie, Li-Ping Xin, Shaolin Xiong, Shuang-Nan Zhang, S.J. Zheng

Instrumentation and Methods for Astrophysics

Using 23 Years of ACS/SBC Data to Understand Backgrounds: Explaining & Predicting Background Variations

Christopher J. R. Clark, Roberto J. Avila, Alyssa M. Guzman et al. (+1 more)

Recent analysis of 23 years of Hubble Space Telescope ACS/SBC data has shown that background levels can vary considerably between observations, with most filters showing over an order of magnitude variation. For the shorter-wavelength filters, the background is understood to be dominated by airglow; however, what precisely drives background variations is not well constrained for any filter. Here, we explore the causes of the background variation. Using over 8,000 archival SBC observations, we developed a machine learning model that can accurately predict the background for an observation, based upon a set of 23 observational parameters. This model indicates that, depending on filter, the SBC background is generally dominated by Solar elevation, Solar separation angle, Earth limb angle of observation, SBC temperature, and target Galactic latitude.
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All authors Christopher J. R. Clark, Roberto J. Avila, Alyssa M. Guzman, Norman A. Grogin

Solar and Stellar Astrophysics

Parallaxes, Proper Motions, and Near-Infrared Photometry for 173 L and T Dwarfs From The US Naval Observatory Infrared Astrometry Program

Frederick J. Vrba, Adam C. Schneider, Jeffrey A. Munn et al. (+11 more)

We present near-infrared parallax and proper motion astrometry for 74 L-dwarfs and 99 T-dwarfs, as single objects or in binary systems, obtained with the ASTROCAM astrometric imager on the USNO, Flagstaff Station 1.55-m telescope over two observing periods. For all 173 objects the median number of observational epochs was 62 with a median time frame of 5.25 years, resulting in median uncertainties of $\sigma$($\pi_{abs}$) = 1.51 mas, $\sigma$($\mu_{abs}$) = 1.02 mas yr$^{-1}$, and $\sigma$($V_{\rm tan}$) = 1.01 km s$^{-1}$. Our observations provide the first parallax/proper motion results for 16 objects and the highest precision parallaxes/proper motions for an additional 116 objects. A serendipitous overlap of 40 objects with Gaia DR3 astrometry allows direct comparison and confirmation of our results, along with an investigation on the effects of resolved binarity on astrometric results. We also provide a uniform set of $J$-, $H$-, $K_{S}$-band photometry in the UKIRT/MKO system, most of it being from new observations. We use these results to examine objects included in this study of special-interest populations, consisting of binaries, wide companions, young objects, subdwarfs, and brown dwarf spectral standards.
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All authors Frederick J. Vrba, Adam C. Schneider, Jeffrey A. Munn, Arne A. Henden, Christain B. Luginbuhl, Conard C. Dahn, Harry H. Guetter, Blaise J. Canzian, Trudy M. Tilleman, Scott E. Dahm, Stephen J. Williams, Justice E. Bruursema, J. Davy Kirkpatrick, Adam J. Burgasser

Astrophysics of Galaxies

Discovery of a new open cluster as a companion to Czernik 38 cluster and its associated complex tide, using Gaia DR3

Nasser M. Ahmed

We utilize Gaia DR3 data to report the discovery of a new star cluster, Nasser 1, located 32 arcmin from Czernik 38 at coordinates $\alpha= 282.11 \pm 0.05$ and $\delta= 4.56 \pm 0.05$. Using a variable membership probability threshold technique with pyUPMASK, we confirm Nasser 1 as a genuine open cluster. It exhibits a distinct King profile and a well-defined CMD with an age of $125.0 \pm 12.30$ Myr, a distance modulus of $12.87 \pm 0.21$ mag, and a color excess of $2.42 \pm 0.09$. Nasser 1 shares consistent physical parameters (age, distance, kinematics, and reddening) with Czernik 38, suggesting they constitute a young primordial binary system in the Carina-Sagittarius spiral arm. Both clusters display elongations indicative of differential rotation tides; Nasser 1 is additionally perturbed by the spiral arm's gravitational field. Gaussian mass function analysis suggests the two were formerly a single cluster, violently torn apart by differential rotation.
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Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc

Constant-roll $\beta$-exponential inflation: Palatini formalism

Ozan Sarg{\i}n

This paper investigates the inflationary dynamics of a $\beta$-exponential potential model within the framework of non-minimally coupled quadratic $(R+R^2)$ gravity. The functional form of the adopted potential provides a well-motivated framework; its physical origin can be interpreted either as the stabilization dynamics of a radion field determining the size of the extra dimension in braneworld cosmology, or as a manifestation of the $q$-exponential function emerging naturally from Tsallis non-extensive thermodynamics. Utilizing the Palatini formalism, we derive an effective Einstein-frame generalized k-inflation theory and analyze its evolution under the constant-roll condition. We perform a comprehensive scan of the parameter space to obtain predictions for the spectral index $n_s$ and the tensor-to-scalar ratio $r$. Our results demonstrate that for specific viable ranges of the model parameters, the inflationary observables are in excellent agreement with the latest observational data from the Atacama Cosmology Telescope (ACT) DR6 and the Planck mission, thereby identifying the physically consistent regions of the parameter space. Furthermore, an evaluation of the primordial non-Gaussianity confirms that the constant-roll dynamics generate a distinct, observationally viable phenomenological signature.
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Cosmology and Nongalactic Astrophysics

A New Constraint on the Optical Depth from the Reionization History Independent of CMB Large-Scale E-Mode Polarization

Yuta Kageura, Masami Ouchi, Fumihiro Naokawa et al. (+5 more)

Recent studies report a mild discrepancy between BAO and CMB measurements within the $\Lambda$CDM framework. This discrepancy could be explained if the optical depth $\tau$ inferred from the CMB large-scale E-mode polarization is underestimated, which may be biased by foreground-subtraction or instrumental systematics. In this work, we present a determination of $\tau$ independent of the large-scale E-mode polarization, using the latest measurements of the redshift evolution of the neutral hydrogen fraction $x_\mathrm{HI}(z)$, which is constrained by Lyman-$\alpha$ forest and damping-wing absorption measurements at $z\sim5$–$14$, based on ground-based optical and JWST observations. Combining $x_\mathrm{HI}(z)$ with the Planck CMB power spectra excluding the large-scale E-mode polarization, we obtain $\tau=0.0552^{+0.0019}_{-0.0026}(\mathrm{stat.})^{+0.0075}_{-0.0049}(\mathrm{sys.})$, where the systematic uncertainty accounts for possible absorption-modeling effects in the inference of $x_\mathrm{HI}(z)$. This constraint is consistent with previous CMB results including the large-scale E-mode polarization. With this measurement, we resolve the degeneracy in the $\tau$–$\Omega_{\rm m}$ plane and find a $2.4\sigma$ tension with the DESI DR2 BAO results, thereby confirming the claimed mild discrepancy suggestive of physics beyond $\Lambda$CDM. Finally, we derive an upper limit on the sum of neutrino masses, $\Sigma m_\nu < 0.0550\,(0.0717)\,{\rm eV}$ at the 95%\,(99%) confidence level. This limit favors the normal mass ordering and, when combined with the lower limits from neutrino oscillation experiments, yields a further constraint, $\Sigma m_\nu = 0.0594_{-0.0007}^{+0.0113}\,{\rm eV}$. However, the cosmological upper limit and the oscillation-based lower limit show a mild $2.2\sigma$ tension, providing an independent indication of possible physics beyond $\Lambda$CDM.
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All authors Yuta Kageura, Masami Ouchi, Fumihiro Naokawa, Hiroya Umeda, Akinori Matsumoto, Yuichi Harikane, Minami Nakane, Tran Thi Thai

Earth and Planetary Astrophysics

Constraining the size, shape, and albedo of the large Trans-Neptunian Object (28978) Ixion with multi-chord stellar occultations

Y. Kilic, F. Braga-Ribas, C. L. Pereira et al. (+81 more)

Trans-Neptunian objects (TNOs) are among the most primitive remnants of the early Solar System, and constraining their sizes, shapes, albedos, and surface properties is essential for understanding their origin and evolution. Stellar occultations provide highly accurate size and shape measurements for TNOs, while photometry constrains their albedo and surface colours. (28978) Ixion is one of the largest TNOs and a prominent Plutino, making it a key target for comparative studies. We aim to constrain Ixion's projected size, shape, absolute magnitude, geometric albedo, and surface colours, and to search for evidence of an atmosphere or circum-object material. We analysed stellar occultation campaigns by Ixion conducted between 2020 and 2023 within the Lucky Star collaboration, comprising 51 observations from eight events, including 30 positive detections. Five multi-chord events enabled a global limb fit and an accurate reconstruction of Ixion's projected shape. The occultations reveal a slightly elongated limb well represented by a single projected ellipse, yielding an area-equivalent diameter of $D_{\mathrm{equiv}} = 696.78^{+10.75}_{-8.87}$ km and an apparent oblateness $\epsilon' = 0.081^{+0.004}_{-0.010}$. Typical radial residuals of order $\sim$10 km indicate a largely stable shape across epochs, with modest epoch-dependent variations. Calibrated photometric data yield an absolute magnitude of $H_V = 3.845 \pm 0.006$, a phase-curve slope of $\beta = 0.1301 \pm 0.0078$ mag deg$^{-1}$, and a visible geometric albedo of $p_V = 0.106^{+0.003}_{-0.003}$, with colours consistent with moderately red TNO surfaces. No atmosphere or circum-object material is detected down to our sensitivity limits. The best-sampled event also allows a precise measurement of the angular diameter of the occulted star Gaia DR3 4056440205544338944, $\theta_\star = 0.670 \pm 0.010$ mas.
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All authors Y. Kilic, F. Braga-Ribas, C. L. Pereira, J. L. Ortiz, B. Sicardy, P. Santos-Sanz, O. Erece, J. L. Rizos, J. M. Gómez-Limón, G. Margoti, D. Souami, B. Morgado, A. Gomes-Junior, L. M. Catani, J. Desmars, M. Kretlow, F. Rommel, R. Duffard, A. Alvarez-Candal, J. I. B. Camargo, M. Kaplan, N. Morales, D. Herald, M. Assafin, G. Benedetti-Rossi, R. Sfair, R. Savalle, J. Arcas-Silva, L. Bernasconi, T. Blank, M. Bonavita, N. Carlson, B. Christophe, C. A. Colesanti, M. Collins, G. Columba, R. Dunford, D. W. Dunham, J. Dunham, M. Emilio, W. G. Ferrante, T. George, W. Hanna, G. Isopi, R. Jones, D. A. Kenyon, S. Kerr, V. Kouprianov, P. D. Maley, F. Mallia, J. Mattei, M. Meunier, T. Napoleao, V. F. Peixoto, J. Pollock, C. Snodgrass, A. Stechina, W. Thomas, R. Venable, G. R. Viscome, A. Zapparata, J. Bardecker, N. Castro, C. Cebral, A. Chapman, C. Gao, K. Green, A. Guimaraes, C. Jacques, E. Jehin, M. Konishi, R. Leiva, L. Liberato, C. Magliano, L. A. Mammana, M. Melita, V. Moura, Y. Olivera-Cuello, L. Peiro, J. Spagnotto, P. C. Stuart, L. Vanzi, A. Wilberger, M. Malacarne

Solar and Stellar Astrophysics

Solar Energetic Proton Events Observed by the High Energy Telescopes on the STEREO Spacecraft or at the Earth During the First Solar Orbit of STEREO A (2006 to 2023)

Ian G. Richardson, Tycho T. von Rosenvinge, O. Chris St. Cyr et al. (+3 more)

The twin STEREO A and B spacecraft were launched in October 2006 into heliocentric orbits at around 1 AU, advancing ahead of or lagging behind Earth, respectively, at around 22 deg./year. The spacecraft provide in-situ observations of the solar wind and energetic particle populations, as well as remote sensing observations of solar activity and the corona. In particular, the High Energy Telescopes (HETs) on the STEREO spacecraft observe 0.7-4 MeV electrons and 13-100 MeV protons. This paper summarizes observations of solar energetic particle (SEP) events made by the STEREO HETs from the beginning of the mission through Solar Cycle 24 to December 2023, approaching the maximum of Solar Cycle 25 and encompassing STEREO A's first full orbit of the Sun relative to Earth, completed in August 2023; contact with STEREO B was lost in October 2014. Specifically, the catalog of SEP events including approximately 25 MeV protons observed by the STEREO HETs and/or instruments on spacecraft near Earth in Richardson et al. (2014) is updated to include around 450 SEP events and a total of around 1000 separate observations of these events from the various spacecraft locations. These extensive observations can provide unique insight into the propagation of energetic protons in the inner heliosphere and how the properties of the particle events are related to those of the associated solar eruptions.
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All authors Ian G. Richardson, Tycho T. von Rosenvinge, O. Chris St. Cyr, David Lario, J. Grant Mitchell, Eric R. Christian

High Energy Astrophysical Phenomena · Cross-listed from gr-qc

Confronting eikonal and post-Kerr methods with numerical evolution of scalar field perturbations in spacetimes beyond Kerr

Ciro De Simone, Sebastian H. Völkel, Kostas D. Kokkotas et al. (+2 more)

The accurate computation of quasinormal modes from rotating black holes beyond general relativity is crucial for testing fundamental physics with gravitational waves. In this study, we assess the accuracy of the eikonal and post-Kerr approximations in predicting the quasinormal mode spectrum of a scalar field on a deformed Kerr spacetime. To obtain benchmark results and to analyze the ringdown dynamics from generic perturbations, we further employ a 2+1-dimensional numerical time-evolution framework. This approach enables a systematic quantification of theoretical uncertainties across multiple angular harmonics, a broad range of spin parameters, and progressively stronger deviations from the Kerr geometry. We then confront these modeling errors with simple projections of statistical uncertainties in quasinormal mode frequencies as a function of the signal-to-noise ratio, thereby exploring the domain of validity of approximate methods for prospective high-precision black-hole spectroscopy. We also report that near-horizon deformations can affect prograde and retrograde modes differently and provide a geometrical explanation.
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All authors Ciro De Simone, Sebastian H. Völkel, Kostas D. Kokkotas, Vittorio De Falco, Salvatore Capozziello

High Energy Astrophysical Phenomena · Cross-listed from physics.plasm-ph

Plasma wakes driven by Compton scattering: Non-linear regime and particle acceleration

Thomas Grismayer, Fabrizio Del Gaudio and Luís O. Silva

We investigate plasma wake generation via Compton scattering from photon bursts, a non-ponderomotive process relevant when the photon wavelength is smaller than the interparticle distance but larger than the Compton wavelength. In this regime, electrons can reach relativistic velocities. We extend linear theory to the nonlinear regime, showing that plasma waves can reach the wave-breaking limit. Perfectly collimated drivers produce wakes propagating at the speed of light, allowing electron phase-locking (limited by driver depletion). Non-collimated drivers induce subluminal phase velocities, limiting acceleration via dephasing. Two-dimensional simulations reveal unique transverse fields compared to laser wakefields, with a DC magnetic field leading to consistent focusing. The work considers observational prospects in laboratory and astrophysical scenarios such as around highly luminous compact objects (e.g., pulsars, gamma-ray bursts) interacting with tenuous interstellar or intergalactic plasmas, where conditions favor Comptondominated wakefield acceleration.
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Solar and Stellar Astrophysics

The Structure and Kinematics of Three Class 0 Protostellar Jets from JWST

Samuel A. Federman, S. Thomas Megeath, Alessio Caratti o Garatti et al. (+20 more)

We present observations of jets within 2000 au of three deeply embedded protostars using 2.9-27 micron observations with JWST. These observations show the morphologies and kinematics of the collimated jets from three protostars, the low-mass Class 0 protostars B335 and HOPS 153, and the intermediate-mass protostar HOPS 370. These jets are traced by shock-ionized fine-structure line emission observed with the JWST NIRSpec and MIRI IFUs. We find that [Fe II] emission traces the full extent of the inner 1000 to 2000 au of the jets, depending on distance to the protostar, while other ions mostly trace isolated shocked knots. The jets show evidence of wiggling motion in the plane of the sky as well as asymmetries between blue and red-shifted lobes. The widths of the jets increase non-monotonically with distance from the central protostar, with opening angles ranging from 2.1 degrees to < 10.1 degrees for the three protostars in the sample. The jets have total velocities ranging from 147 to 184 km/s after correcting for disk inclination. For B335, an 8-month gap between NIRSpec and MIRI MRS observations enabled measurement of the tangential velocity of a shocked knot; in combination with the radial velocity, this shows that the jet has a different inclination than the outflow cavity. We find multiple knots before and during a recent outburst in B335, although the knots were more frequent during the burst. The asymmetries between blue- and red-shifted lobes strongly suggest complex interactions between the circumstellar disks and magnetic fields.
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All authors Samuel A. Federman, S. Thomas Megeath, Alessio Caratti o Garatti, Mayank Narang, Himanshu Tyagi, Neal J. Evans II, Carolin N. Kimmig, Lukasz Tychoniec, Henrik Beuther, Amelia Stutz, P. Manoj, Robert Gutermuth, Tyler L. Bourke, Joel Green, Lee Hartmann, Pamela Klaassen, Rolf Kuiper, Leslie W. Looney, Pooneh Nazari, Thomas Stanke, Dan M. Watson, Yao-Lun Yang, Wafa Zakri

High Energy Astrophysical Phenomena

Blowouts of Nascent Wind Bubbles in Pulsar-Driven Supernovae

Mingxi Chen, Kazumi Kashiyama and Masato Sato

Formation of a rapidly spinning, strongly magnetized neutron star (NS) may occur in various classes of core-collapse events. If the NS injects an amount of energy comparable to the explosion energy of the accompanying supernova (SN) before the SN ejecta becomes transparent, the nascent NS wind bubble can overtake the outer ejecta and undergo a blowout driven by hydrodynamic instabilities. Based on multidimensional numerical studies, we construct a minimal semi-analytic framework to follow the post-blowout dynamics and radiative evolution, map the blowout conditions by scanning the ejecta and NS parameters, and compute survey-ready multi-band light curves. For stripped-envelope SNe with an ejecta mass of $M_\mathrm{ej} \sim 10\,M_\odot$ and an explosion energy of $E_\mathrm{sn} \sim 10^{51}\,\mathrm{erg}$, blowout occurs for NSs with magnetic field strengths of $B_{\mathrm{dip}} \gtrsim 10^{13}\,\mathrm{G}$ and spin periods of $P_\mathrm{NS} \lesssim \mathrm{a\ few}\,\mathrm{ms}$. Relatively weak-field cases with $B_\mathrm{dip} \lesssim 10^{14}\,\mathrm{G}$ produce luminous double-peaked UV/optical light curves, as observed in the superluminous SN LSQ14bdq, while stronger-field cases with $B_\mathrm{dip} \gtrsim 10^{14}\,\mathrm{G}$ result in hypernovae preceded by X-ray blowout precursors. We also examine weaker and lower-mass SN explosions representing ultra-stripped SNe and accretion- or merger-induced collapse events, in which blowout is more readily achieved over a broader range of NS parameters, producing fast X-ray transients with durations of $ 10^{2\mbox{--}4}\,\mathrm{s}$ and peak luminosities of $10^{42\mbox{--}48}\,\mathrm{erg\,s^{-1}}$. Our results encourage coordinated UV, optical, and X-ray observations which constrain the formation of the most energetic NSs in the universe.
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Solar and Stellar Astrophysics

Quiet Sun impulsive events observed with NuSTAR during solar minimum

Sarah Paterson, Iain G. Hannah, Brian W. Grefenstette et al. (+6 more)

The investigation of small-scale energy release in the Sun's atmosphere is important in understanding how the corona is heated. Previous work has been able to study small EUV and SXR brightenings outside of active regions (i.e. the quiet Sun), but with HXRs this has mostly focused on active region transients/microflares due to the sensitivity of available telescopes. In this paper we present observations of the quiet Sun with the Nuclear Spectroscopic Telescope Array (NuSTAR), an X-ray imaging spectrometer with much greater sensitivity than previous instruments, allowing the observation of faint events. During the recent solar minimum, NuSTAR captured seven quiet Sun flares/impulsive brightenings, three on 21 February 2020, and four on 12-13 September 2020. From fitting their NuSTAR HXR spectra we find temperatures of 3.1-4.0 MK and emission measures between (0.75-17.0) $\times 10^{43}$ cm$^{-3}$, which gives thermal energies between (2.5-8.9) $\times 10^{26}$ erg. Only one event, a mini-filament eruption, showed evidence of slightly higher temperatures emission, confirmed through Differential Emission Measure analysis. None of the events showed evidence of non-thermal emission in their NuSTAR spectra, and we placed upper limits to the accelerated electron population. The thermal parameters for these quiet Sun events seem to scale differently to previously studied active region flares, suggesting a different energy release process might be dominating. However, this conclusion is affected by the different sensitivity and biases introduced by the various instruments and analysis approaches used.
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All authors Sarah Paterson, Iain G. Hannah, Brian W. Grefenstette, Säm Krucker, Erica Lastufka, Hugh S. Hudson, Lindsay Glesener, Stephen M. White, David M. Smith

High Energy Astrophysical Phenomena

Strange quark star II: the minimal and maximal gravitational mass and the Keplerian configuration

Fatemeh Kayanikhoo, Mateusz Kapusta, Miljenko Čemeljić et al. (+2 more)

We employ the MIT bag model with density-dependent bag constant for the equation of state (EOS) to estimate the gravitational mass and Keplerian frequency of rapidly rotating strange quark stars (SQS). In a companion paper we discuss the structural parameters of such rotating stars under the influence of strong magnetic fields. We use the LORENE library to compute the structural parameters at different rotational frequencies in the range of 1100-1300~Hz for a non-magnetized SQS. While there is no minimum limit for the mass of slowly rotating self-bound stars, by computing the maximum rotational frequency, known as the mass-shedding limit, we show that SQS must have a minimum mass to sustain high rotational frequencies. The mass-shedding frequency in our EOS model is lower than that estimated from the MIT bag model EOS with a fixed bag constant. The Keplerian frequency in our model depends linearly on the gravitational mass at the mass-shedding limit (and similarly on the minimum mass) with the slope of 0.08~${\rm kHz}/M_\odot$. We obtain mass limits aligned with the observational data for both the heaviest and the lightest observed pulsars.
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All authors Fatemeh Kayanikhoo, Mateusz Kapusta, Miljenko Čemeljić, Wlodek Kluzniak, Leszek Zdunik

High Energy Astrophysical Phenomena

Strange quark star I: the maximum gravitational mass and deformation of magnetized spinning model

Fatemeh Kayanikhoo, Mateusz Kapusta, Miljenko Čemeljić et al. (+1 more)

We investigate the structural parameters of strange quark stars (SQS) under the influence of strong magnetic fields and varying rotational frequencies. The equation of state is computed using the MIT bag model with a density-dependent bag constant and considering the Landau quantization effect regarding the strong magnetic fields up to $5\times10^{17}\,$G in the interior of SQS. Employing the LORENE library, we calculate the structural parameters under different magnetic field strengths and rotational frequencies. Our models are compared in terms of maximum gravitational mass, deformation parameter, binding energy, and compactness. Our equation of state model demonstrates that the gravitational masses are higher than those computed using a MIT bag model with a fixed bag constant. We find the gravitational masses beyond $2.3 \,M_\odot$, which are compatible with the masses of observed compact objects, such as the “black widow” pulsar PSR J0952-0607, and the GW190814 event detected by the LIGO/Virgo collaboration. The deformation parameter and maximum gravitational mass of SQS are characterized by fitted functions accounting for variations in both magnetic field strength and rotational frequency. We find the maximum deformation parameter of 1.55 and the maximum gravitational mass of $2.8\, M_\odot$ in the fast-rotating strongly magnetized model.
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All authors Fatemeh Kayanikhoo, Mateusz Kapusta, Miljenko Čemeljić, Leszek Zdunik

Cosmology and Nongalactic Astrophysics

Simultaneous determination of Hubble constant and cosmic baryon density: Forecasts for the synergy between FRBs and emerging probes

Peng-Ju Wu, Bo-Yang Zhang, Ji-Guo Zhang et al. (+3 more)

Two of the most pressing challenges in cosmology are the persistent discrepancy in measurements of the Hubble constant, referred to as the Hubble tension, and the deficit of baryons in the local Universe, known as the missing baryon problem. Fast radio bursts (FRBs) provide a unique probe of both the Hubble constant $H_0$ and the cosmic baryon density $\Omega_{\rm b}$. However, constraints from FRBs alone suffer from a severe $H_0$-$\Omega_{\rm b}$ degeneracy that prevents them from resolving either problem. We show that this degeneracy can be broken by combining FRBs with other emerging probes whose degeneracy directions differ in the $H_0$-$\Omega_{\rm b}$ plane. Specifically, we quantify three multi-messenger approaches: FRBs paired with gravitational wave (GW) standard sirens, strong gravitational lensing (SGL) time delays, and 21 cm intensity mapping (IM) surveys. The combinations FRB+GW, FRB+SGL, and FRB+21 cm IM each deliver simultaneous constraints on $H_0$ and $\Omega_{\rm b}$ better than (1%, 1.5%) in the $\Lambda$CDM model, and when dynamical dark energy is introduced, the constraining precision degrades gracefully as model complexity increases. Furthermore, within a model-independent framework, both FRB+GW and FRB+SGL constrain $H_0$ and $\Omega_{\rm b}$ to precisions better than (1.5%, 3%). These precision levels are based on nominal observational expectations and would improve significantly under optimistic observational scenarios.
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All authors Peng-Ju Wu, Bo-Yang Zhang, Ji-Guo Zhang, Guo-Hong Du, Shang-Jie Jin, Xin Zhang

Earth and Planetary Astrophysics

Demographics of Close-In TESS Exoplanets Orbiting FGK Main-sequence Stars

Kaiming Cui, David J. Armstrong, Andreas Hadjigeorghiou et al. (+5 more)

Understanding the demographics of close-in planets is crucial for insights into exoplanet formation and evolution. We present a detailed analysis of occurrence rates for close-in (0.5-16 day) planets with radii between 2 and 20$\,R_{\oplus}$ around FGK main-sequence stars. Our study uses a comprehensive sample from four years of TESS Science Processing Operations Center full-frame image data cross-matched with Gaia, analysed through our rigorous detection, vetting, and validation pipeline. Using high-confidence planet candidates, we apply a hierarchical Bayesian model to determine occurrence rates in the two-dimensional orbital period-radius plane. Our results are presented using 10-by-10 bins across the period-radius parameter space, offering unprecedented resolution and statistical precision. We find an overall occurrence rate of $9.4^{+0.7}_{-0.6}\%$. When using identical binning, our occurrence rate posteriors distributions align with Kepler's but have a magnitude smaller uncertainties on average. For hot Jupiters, we estimate the overall occurrence rate of $0.39^{+0.03}_{-0.02}\%$. This value is consistent with the previous Kepler FGK-type result within $1\sigma$. We find an overall occurrence rate of Neptunian desert planets of $0.08\pm0.01\%$, to our knowledge the first such determination. Additionally, in a volume-limited Gaia subsample within 100 pc in the same parameter region, we measure an overall planet occurrence rate of $15.4^{+1.6}_{-1.5}\%$ and a hot Jupiter occurrence rate of $0.42^{+0.16}_{-0.12}\%$. Our results establishes an improved foundation for constraining theoretical models of exoplanet populations.
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All authors Kaiming Cui, David J. Armstrong, Andreas Hadjigeorghiou, Marina Lafarga, Vedad Kunovac, Lauren Doyle, Luis Agustín Nieto, Rodrigo F. Díaz