High Energy Astrophysical Phenomena · Cross-listed from hep-ph
Production of Leptophilic Bosons in Ultradegenerate Relativistic Matter
Damiano F. G. Fiorillo, Alessandro Lella, Georg G. Raffelt et al. (+2 more)
Neutron stars (NSs) are powerful factories for new particles with masses up to the 100~keV range. These compact
stars contain significant amounts of
protons, electrons, and
muons. We deduce the emission rates for new scalar, vector, and pseudoscalar
bosons coupling to electrons and
muons. For muonic vector
bosons, in addition to direct emission from
leptons in incoherent scatterings with the medium, a competing channel is the coherent excitation of the
lepton population electromagnetically induced by incoherent hadronic scatterings - an effective in-medium coupling. For muonic scalar
bosons, emission from the effective in-medium coupling to electrons is always dominant due to their relativistically boosted emission. Pseudoscalars can only be emitted through incoherent leptonic scatterings. If
protons are superconducting, the scalar and vector energy loss rates scale as $T^4$, the pseudoscalar ones as $T^6$, to be compared with $T^8$ for
neutrino losses by the modified Urca (MUrca) process. For normal-conducting
protons, the damping of transverse
photons implies instead scalings with a power $T^{11/3}$ for scalars, and $T^{17/3}$ for pseudoscalars; vectors, emitted by nonrelativistic
protons in the nonsuperconducting regime, still scale as $T^4$. Our results can be used to constrain the leptophilic coupling strengths through observed NS cooling ages.
Read the full abstract ▾
All authors Damiano F. G. Fiorillo, Alessandro Lella, Georg G. Raffelt, Nudzeim Selimovic, Edoardo Vitagliano
High Energy Astrophysical Phenomena
Minor Merger, Major Growth: An Overmassive, Highly Accreting Black Hole Powering a Secondary AGN In a Cosmic Noon Minor Merger
Marko Mićić
We report the discovery of a spectroscopically confirmed z = 1.824 minor merger with a mass ratio of ~35:1 in which the secondary (smaller)
galaxy hosts a luminous AGN. The system is identified in the 3D-HST survey and exhibits clear
tidal features in James Webb Space
Telescope imaging, confirming an ongoing interaction. Using archival Chandra X-ray observations, we detect 121 +/- 11 X-ray counts associated with the secondary
galaxy, corresponding to a rest-frame 2-10 keV luminosity of L_X ~ (9 +/- 0.1) x 10^43 erg/s and a
photon index of Gamma ~ 2.0-2.3. Analysis of the HST/WFC3 G141 grism spectrum yields an [O III] lambda5007 luminosity of (2 +/- 0.5) x 10^42 erg/s. Independent bolometric luminosity estimates from X-ray and [O III] emission are consistent, implying L_bol ~ (3-7) x 10^45 erg/s. Assuming standard black hole-
galaxy scaling relations, the expected black hole mass is ~2 x 10^6 M_sun, which would require extreme super-Eddington
accretion to explain the observed luminosity. On the other hand, assuming Eddington-limited or moderately sub-Eddington
accretion implies a black hole mass more than an order of magnitude above expectations. The observed X-ray spectral slope disfavors low
accretion rates, restricting the allowed parameter space to high lambda_Edd and elevated black hole masses. We conclude that the secondary AGN must be powered by an overmassive, highly accreting black hole, providing direct observational support for theoretical predictions that minor mergers can drive rapid black hole growth in secondary, smaller companions.
Read the full abstract ▾
Cosmology and Nongalactic Astrophysics
cloelike: A Python Library for Cosmological Likelihood Inference in the Euclid Era
Marco Bonici, Guadalupe Cañas-Herrera, Pedro Carrilho et al. (+16 more)
cloelike is a Python package providing modular, composable Gaussian likelihood classes for the main cosmological large-scale structure observables targeted by the ESA Euclid space mission. It is a core component of the CLOE (Cosmology Likelihood for Observables in Euclid) ecosystem and interfaces directly with cloelib for theoretical predictions and euclidlib for reading official Euclid data products. The package implements Gaussian likelihoods covering harmonic angular power spectra and real-space two-point correlation functions for weak
lensing (WL), photometric
galaxy clustering (GCph), and
Galaxy-
Galaxy Lensing (GGL) in all joint probe combinations (3x2pt, 2x2pt), as well as spectroscopic full-shape power spectrum multipoles, and baryonic Acoustic oscillations (BAO). cloelike is actively used in internal Euclid Consortium analyses and is openly released to support community validation and reproducibility.
Read the full abstract ▾
All authors Marco Bonici, Guadalupe Cañas-Herrera, Pedro Carrilho, Santiago Casas, Chiara Moretti, Andrea Pezzotta, Zahra Baghkhani, Carmelita Carbone, Martin Crocce, Jip de Buck, Klara Bertmann, Nastassia Grimm, Martin Kärcher, Felicitas Keil, Davide Sciotti, Peter L. Taylor, Nicolas Tessore, Isaac Tutusaus, Casper Vedder
Cosmology and Nongalactic Astrophysics
cloelib: A Flexible Python Library for Computing Cosmological Observables in the Euclid Era
Marco Bonici, Guadalupe Cañas-Herrera, Pedro Carrilho et al. (+54 more)
cloelib is a Python library developed to compute cosmological observables within the Cosmology Likelihood for Observables in Euclid (CLOE) ecosystem (cloe-org). As cosmology enters a precision era driven by
galaxy survey missions such as Euclid, there is a growing need for flexible, efficient, and differentiable software capable of supporting next-generation inference pipelines. cloelib addresses these demands through a modular architecture that interfaces seamlessly with established Boltzmann solvers whilst incorporating JAX-based automatic differentiation to enable gradient-based methods. The library defines consistent protocols for background
evolution, perturbations, and non-linear structure formation, and supports a wide range of observables, including photometric and spectroscopic large-scale structure probes, as well as cross-correlations with the
Cosmic Microwave Background and
galaxy clusters. In its finalised form, cloelib is intended to serve as the reference theory computation infrastructure for Euclid's first cosmological release, bridging traditional numerical cosmology with modern optimisation techniques and emerging machine learning approaches to inference.
Read the full abstract ▾
All authors Marco Bonici, Guadalupe Cañas-Herrera, Pedro Carrilho, Santiago Casas, Chiara Moretti, Andrea Pezzotta, Michel Aguena, Giovanni Aricó, Zahra Baghkhani, Matteo Baratto, Emilio Bellini, Jip de Buck, Klara Bertmann, Ben Bose, Jeger C. Broxterman, Pierre Burger, Carmelita Carbone, Chaitanya Chawak, Jose Coloma-Nadal, Martin Crocce, Stefano Davini, Christopher A. J. Duncan, Samuel Farrens, Lisa Goh, Nastassia Grimm, Alex Hall, Ryusei R. Kano, Martin Kärcher, Felicitas Keil, Raphaël Kou, Laila Linke, Arthur Loureiro, Katarina Markovic, David Navarro-Gironés, Filippo Oppizzi, Gabriele Parimbelli, Anna Porredon, Robert Reischke, Jaime Ruiz Zapatero, Iñigo Sáez-Casares, Ziad Sakr, Neel Shah, Davide Sciotti, Matthieu Schaller, Ivan Sladoljev, Arghavan Souki, Sankarshana Srinivasan, Konstantinos Tanidis, Peter L. Taylor, Nicolas Tessore, Linus Thummel, Maria Tsedrik, Isaac Tutusaus, Casper Vedder, Angus H. Wright, Miguel Zumalacárregui, Joe Zuntz
Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc
Natural Metric-Affine Inflation: Reloaded
D. Kraiko and A. Racioppi
We revisit natural inflation within the framework of metric-affine
gravity, considering the impact of a periodic non-minimal coupling between the inflaton and the Nieh-Yan term. Such a term, alone, leads to linear inflation predictions in the strong coupling limit and cannot help to rescue the natural inflation scenario. However, once an analogous non-minimal coupling with the
Ricci scalar is added, agreement with data can be easily achieved. Remarkably, the scenario remains viable even with a sub-Planckian periodicity scale and relatively small (order of one) non-minimal couplings.
Read the full abstract ▾
High Energy Astrophysical Phenomena
An extremely bright slow-rising afterglow from an off-axis jet in GRB 260310A
Yu-Han Yang, Roberto Ricci, Eleonora Troja et al. (+31 more)
We present a multi-wavelength study of GRB 260310A, a nearby long-duration gamma-ray burst at $z\simeq0.153$ associated with a broad-lined Type Ic
supernova. Despite its modest
prompt gamma-ray output, $E_{\gamma,\rm iso}\simeq3.5\times10^{50}$ erg, GRB 260310A exhibits one of the brightest afterglows ever observed in the X-ray, optical, and
radio bands. Its apparent brightness is not its only remarkable feature. The optical afterglow displays a delayed onset, characterized by a slow rising phase, with slope $\alpha\approx-1$, and a late peak at $\approx$0.1 d. We argue that the combination of weak
prompt emission, hard peak energy, and late afterglow onset is naturally explained by a GRB jet viewed off-axis. The
radio spectral energy distributions are consistent with synchrotron radiation and indicate the presence of both reverse- and forward-shock components, thus providing a first test of reverse-shock models in an off-axis geometry. The X-ray afterglow displays a prominent rebrightening, monitored for up to $\approx$68 d with no evidence of spectral
evolution. A low level of linear polarization, $\Pi\approx1.7\%$, is measured at 15 GHz at $T_0+55$ d and suggests that, at these late times, the forward-shock is the dominant emission component from
radio to X-rays. This late-time rebrightening represents a critical test for the two-component jet model. If interpreted as the emergence of a narrow jet core viewed further off-axis, it would imply extreme luminosities and energetics for an on-axis observer.
Read the full abstract ▾
All authors Yu-Han Yang, Roberto Ricci, Eleonora Troja, Muskan Yadav, Yi-Han Iris Yin, Rubén Sánchez-Ramírez, Brendan O'Connor, Niccoló Passaleva, Alberto J. Castro-Tirado, Hendrik van Eerten, Simone Dichiara, Vincenzo Galluzzi, Narjes Shahamat Dehsorkh, Iván Agudo, Jesús Aceituno, Malte Busmann, María D. Caballero-García, Emilio Fernández-García, Daniel Gruen, Maria Gritsevich, Sergiy Guziy, David Hiriart, You-Dong Hu, Martin Jelínek, Alexander Kutyrev, Alzbeta Malenakova, Filip Novotny, Ignacio Pérez-García, Shashi B. Pandey, Jorma Ryske, Alfredo Sota, Jan Strobl, Hira Waseem, Siyu Wu
Instrumentation and Methods for Astrophysics
Integral field spectroscopy with no IFUs: combining wide-field rotational slitless spectroscopy with tomographic reconstruction
Jerry Jun-Yan Zhang and Francesco Sinigaglia
Among spectroscopic techniques, Integral Field Spectroscopy (IFS) is regarded as one of the most versatile and powerful, but it is limited by small FoVs, complex designs, and high costs. We hereby present ROSSINI: the ROtational Slitless Spectrograph for INtegral field spectroscopy and Imager, a novel spectrograph design aimed at performing IFS without IFUs but in a slitless fashion instead. The device relies on generating a series of independent detector images of the same field by rotating the whole
telescope and/or the dispersion direction of the optical element, and on a postprocessing tomographic reconstruction
algorithm, yielding a full IFS datacube with arbitrary angular and spectral pixelization defined by the user. We first develop the mathematical formulation of the problem and derive the solution as a linear
matrix inversion. Then, we provide an interpretation of ROSSINI as a particular application of
tomography and leverage this to propose a practical numerical solution based on iterative reconstruction. We test this novel conception through a series of numerical experiments: we first generate toy datacubes on the sky, then simulate the spectrograph and the corresponding detector images, and finally apply tomographic reconstruction, recovering the input datacube. The number of needed rotations can be easily computed from the relative pixelization of the datacube and the pixel number of the detector. From the numerical experiments, ROSSINI turns out to be able to reconstruct the
benchmark datacubes with percent accuracy and in just a few hundred iterations, using negligible computational resources. ROSSINI is a promising way forward for future spectroscopic facilities, as it allows us to perform wide-field IFS in an efficient and cheap fashion by relying mostly on existing slitless spectrograph technologies.
Read the full abstract ▾
Astrophysics of Galaxies
Astrophysical Parameters of 5056 Open Star Clusters from Bayesian Nested Sampling with PARSEC Isochrones
Olcay Plevne and Furkan Akbaba
We present a homogeneous catalogue of ages,
metallicities, distances, and reddenings for 5056 open clusters in the Unified Cluster Catalogue (UCC), derived uniformly from
Gaia Data Release 3 (DR3) colour-magnitude diagrams via
Bayesian nested sampling with PARSEC isochrones. Unlike previous large-scale catalogues,
metallicity is fitted as a free parameter for every cluster rather than fixed or adopted from the literature: where available,
Gaia XP spectrophotometric
metallicities inform the fit (1201 clusters), while the remaining clusters are constrained by broad priors from
Gaia parallaxes and the Schlegel-Finkbeiner-Davis
dust map. No cluster is anchored to an external open-cluster parameter catalogue, and no per-cluster manual intervention is applied. A fit-quality metric, $\eta_{\rm fit}$, identifies 3807 clusters (75 per cent) with reliable colour-magnitude solutions, spanning ages of 0.004-5.9 Gyr and distances out to 17 kpc. We validate the resulting parameters against six literature catalogues and, more critically, against independent high-resolution spectroscopic
metallicities from OCCAM DR19: for 132 clusters in common we find a median absolute deviation of only 0.054 dex ($-0.021 \pm 0.132$ dex mean offset), comparable to the intrinsic systematic uncertainty of isochrone-based
metallicities. As a direct consequence of this fidelity, the radial
metallicity gradient recovered from our XP-informed clusters ($-0.064$ dex kpc$^{-1}$) steepens towards the spectroscopically calibrated value ($-0.079$ dex kpc$^{-1}$) for the highest-quality subset - demonstrating that a purely photometric pipeline, built without reference to spectroscopy, recovers a physically meaningful abundance scale. The full catalogue and posterior chains are publicly released.
Read the full abstract ▾
Astrophysics of Galaxies
Unsupervised Chemo-Dynamical Dissection of the Inner Galactic Halo: Discovery of Five Accreted Substructures with SDSS-V and Gaia
Furkan Akbaba and Olcay Plevne
The inner
Galactic halo is a complex graveyard of the Milky Way's earliest
accretion events, where severe orbital phase-mixing challenges traditional dynamical stream-finding techniques. We present a purely data-driven, 12-dimensional chemo-dynamical analysis of the inner
halo using SDSS-V Milky Way Mapper (DR19) and
Gaia DR3. Utilizing an unsupervised machine learning framework based on UMAP and HDBSCAN, we perform a blind search for clustered populations within a chemically selected ex-situ sample of 2,185
stars without kinematic pre-selection. Our pipeline recovers nine kinematic groupings corresponding to seven known substructures (including
Gaia-Enceladus/Sausage, the Helmi Streams, and Sequoia), validating the robustness of the high-dimensional feature space. We also report five new tightly bound candidate substructures, designated FO1–FO5 ($E_{\rm tot} \leq -1.8 \times 10^5~\mathrm{km^2~s^{-2}}$). Four candidates (FO1, FO3, FO4, FO5) are confirmed as robust chemo-dynamical overdensities, while FO2 exhibits a striking nitrogen enhancement ($[\mathrm{N/Fe}] = +0.83 \pm 0.16$) suggestive of
tidal debris from a disrupted massive globular cluster. Finally, we demonstrate that high-dimensional chemical information is critical for resolving dynamical degeneracies in the crowded inner
halo, differentiating structures sharing similar orbits but distinct chemistry (e.g., FO5 and Shiva), and the reverse (e.g., FO3 and the Helmi Streams). These findings confirm that the deepest regions of the
Galactic potential preserve a rich record of the
Galaxy's assembly history.
Read the full abstract ▾
Solar and Stellar Astrophysics
Sharper Than Ever: Do Modern Observations Pin Down the Solar Radius to Converge on New Standards?
Jean-Pierre Rozelot and Alexander Kosovichev
Solar radius measurements and their variations – if any – are a difficult problem that has vexed researchers for decades. In this paper, we have attempted to clarify the various ways of expressing the definition ”
solar diameter”, from a physical point of view. The concept of diameter is taken here in its broadest sense, leaving aside the issue concerning the oblateness caused by surface and internal angular velocity variations, as deviations from sphericity are negligible in our context. Astrometric time-series observations are still needed, and we advocate strengthening long-term metrological measures to achieve greater consensus on the subject. To date, modern observations of the
solar diameter provide a frame of reference, and we give a new glossary. By comparing the best values obtained to date, it is shown that the ”seismic radius” obtained from the
Solar and Heliospheric Observatory (SOHO) and the
Solar Dynamics Observatory (SDO) provides the best determination, a finding supported by observations made at the Calern (F) and Pic du Midi (F) observatories. The latest results on the leptocline show that it is more important than ever to consider at which layers of the Sun radius measurements are carried out. On this basis, we hope to converge on new standards.
Read the full abstract ▾
Astrophysics of Galaxies
Gaia FGK benchmark stars: Abundances of n-capture elements of the third version
S. Vitali, P. Jofré, L. Casamiquela et al. (+10 more)
In the current era, in which an unprecedented wealth of data are available for the study of the Milky Way,
Gaia benchmark stars (GBSs) have become an established reference and calibration sample. Studies of
stellar structure and
evolution and of the chemical history of our
Galaxy generally rely on large spectroscopic surveys and their output catalogs. In this context, deriving precise and accurate
stellar parameters and chemical abundances is of paramount importance. This study provides the determination of
neutron (n)-capture element abundances and extends the set of chemical abundances available for the third GBS release (GBSv3). Based on the compilation of high-resolution spectra assembled for GBSv3 and consistent with the spectral analysis adopted for the chemical abundances of GBSv3, we used the public iSpec code to derive heavy element abundances. We inferred homogeneous abundances of n-capture elements across the GBSv3 sample using an in-depth line assessment tailored to different groups identified through a clustering
algorithm that accounts for the diversity in
stellar parameters and
metallicities. This approach addresses key challenges in the spectral analysis of these elements, including the paucity of usable lines, weak line strengths, saturation effects, and sensitivity to atomic data. The assessment yielded reliable measurements, establishing an extended and robust reference scale in good agreement with the literature. This compilation of n-capture abundances is based on the GBS sample's accurate atmospheric parameters and the analysis of a large sample of
stellar spectra per
star, which provides a reliable and homogeneous spectral analysis. It also supports the use of chemical abundances as precise tracers of the Milky Ways
star formation history and chemical
evolution and constitutes a legacy sample for the calibration of current and future spectroscopic surveys.
Read the full abstract ▾
All authors S. Vitali, P. Jofré, L. Casamiquela, C. Soubiran, U. Heiter, C. Aguilera Gómez, D. Barrios López, S. Blanco Cuaresma, A. Escorza, I. Hernández Araya, T. Signor, H. Sinclair Wentworth, C. Worley
Earth and Planetary Astrophysics · Cross-listed from eess.SY
Reachability for Low-Thrust Trajectories via Maximum Initial Mass
Giacomo Acciarini, Dario Izzo and Zhong Zhang
Reachability analysis plays a central role in low-thrust spacecraft trajectory optimization by identifying which target states can be achieved under constraints on time, thrust, and propellant. Classical approaches construct reachable sets by solving many optimal control problems over grids of terminal states, requiring extensive forward simulations with fixed initial conditions. While effective, this approach is computationally expensive and becomes impractical for high-dimensional systems or strongly nonlinear dynamics, such as those encountered in cislunar environments or
solar sail missions. This work introduces a dual formulation of the reachability problem. Instead of computing reachable sets directly, we determine, for fixed transfer time and boundary conditions, the maximum allowable initial mass (or, for
solar sails, a scalar sail-strength parameter) that permits a successful transfer. A target is reachable if the spacecraft's initial mass does not exceed this threshold. This reformulation reduces reachability assessment to a scalar optimization problem for each target, producing a smooth scalar field that encodes equivalent feasibility information to classical reachable sets. We develop indirect maximum-initial-mass (MIM) formulations for both electric low-thrust and
solar-sail dynamics and show how they can serve as efficient reachability oracles. Building on this formulation, we construct data-driven surrogate models to approximate the MIM-based reachability indicator. We investigate fully connected neural networks and demonstrate that residual networks provide the best trade-off between accuracy, training stability, and model complexity. The resulting surrogates enable rapid reachability evaluation while preserving the numerical advantages of the dual formulation, offering a practical tool for preliminary mission design and feasibility assessment.
Read the full abstract ▾
Solar and Stellar Astrophysics
GMRT Survey of Radio Emission from Magnetic Massive Stars – I: Emission from Single Stars at sub-GHz Frequencies
Ayan Biswas, Gregg A. Wade, Barnali Das et al. (+2 more)
With the growing subset of
magnetic massive
stars, it is now possible to conduct a systematic survey of
radio emission from
magnetic hot
stars to better understand the underlying emission mechanisms. Previous surveys of
radio emission from hot
star magnetospheres have focused on high frequencies ($>$2 GHz). At lower frequencies, additional emission and absorption mechanisms are expected, increasing the complexity of the observed emission. In this work, we survey towards lower frequencies while also increasing the sample size. We report the study of 28
magnetic hot
stars with the
Giant Metrewave
Radio Telescope (GMRT) during cycles 27 and 28 of its operation. Among these, we found 11 detections and 17 non-detections. We also include 16 additional targets observed with GMRT from the literature. We investigated the dependence of low-frequency
radio luminosity on different
stellar parameters and searched for a scaling relationship at low frequencies. We further test the centrifugal breakout model for gyrosynchrotron emission. The observed low-frequency
radio luminosities show a clear dependence of
radio emission on
magnetic field strength and rotation period, consistent with high-frequency studies. We observe a trend in scaling relationships with frequency and comment on the statistical behavior of gyrosynchrotron spectra. The observed low-frequency behavior likely reflects a combination of free-free absorption and the location of the low-frequency turnover in the gyrosynchrotron spectrum, which may vary among
stars depending on their magnetospheric properties and can suppress detectable sub-GHz emission. One of the detected
stars, HD 37742, is the first
magnetic O-type
star detected at sub-GHz frequencies.
Read the full abstract ▾
All authors Ayan Biswas, Gregg A. Wade, Barnali Das, Veronique Petit, Matthew E. Shultz
Solar and Stellar Astrophysics
Probing Solar Wind Structures with Solar Energetic Particle Observations from Solar Orbiter
Xiaohang Chen, Gang Li, Joe Giacalone et al. (+12 more)
The propagation of
solar energetic particles (SEPs) through the heliosphere is primarily guided by the interplanetary
magnetic field (IMF) which is embedded in the
solar wind
plasma. Large-scale IMF structures can drive transient variations in SEP intensities. Using
Solar Orbiter observations, we identify a distinct class of SEP variations: SEP flux deflections (SFDs), which are commonly detected in SEP events and frequently recur multiple times within a single event. SFDs are characterized by a sudden change in SEP flux directions where the intensities drop in one direction and increase in another direction, without a significant net change in total flux magnitude. These deflections occur dispersionlessly across a broad energy range-from tens of keV to over 100 MeV-and exhibit steep intensity gradients. SFDs are typically associated with
magnetic flux tubes with boundary features consistent with tangential discontinuities. We further show that the
solar wind inside these structures exhibits distinct
plasma properties, and that the SEP streaming direction within SFDs aligns closely to the flux-tube axis. These observations suggest that
magnetic flux tubes are a prevalent structural element of the
solar wind, and demonstrate that SEPs can serve as an effective diagnostic tool for probing the
topology and dynamics of
solar wind structures.
Read the full abstract ▾
All authors Xiaohang Chen, Gang Li, Joe Giacalone, Xiangliang Kong, Shuai Fu, Rumeng Zhang, Changyue Zhao, George C. Ho, David Lario, Zheyi Ding, Robert F. Wimmer-Schweingruber, Glenn M. Mason, Roberto Bruno, Nicolas Wijsen, Javier Rodríguez-Pacheco
Astrophysics of Galaxies
Probing the environments of FRI and FRII radio galaxies in LoTSS DR2 with galaxy clusters
Tong Pan, Yuming Fu, H. J. A. Rottgering et al. (+7 more)
The origin of the Fanaroff–Riley Class I/II (FRI/FRII) morphological dichotomy remains uncertain. We investigate whether cluster-scale environment contributes to this distinction using a morphologically classified LoTSS DR2 catalogue at \(z<0.4\). We construct a volume-limited sample with \(L_{144}>4\times10^{24}\,\mathrm{W\,Hz^{-1}}\) and a luminosity–
redshift paired sample, and cross-match them with DESI Legacy Imaging Survey
galaxy clusters. A
radio galaxy is associated with a cluster if \(|\Delta z|<0.01\), projected separation \(<2R_{500}\). In the volume-limited sample, \(48.6\%\) of FRIs and \(30.6\%\) of FRIIs are cluster-associated; in the paired sample, the corresponding fractions are \(45.6\%\) and \(32.6\%\). The difference is stronger at \(L_{144}>10^{26}\,\mathrm{W\,Hz^{-1}}\), where the fractions are \(55.6\%\) versus \(19.0\%\) in the volume-limited sample and \(50.0\%\) versus \(6.7\%\) in the paired sample. However, cluster-associated FRIs and FRIIs occupy similar environments: their
radio luminosities and
stellar masses show similar trends with cluster richness and \(M_{500}\), and their radial distributions both peak near \(0.5R_{500}\) and decline beyond \(R_{500}\). Most cluster-associated sources are brightest cluster
galaxies (BCGs), with fractions of \(74.8\%\) for FRIs and \(61.9\%\) for FRIIs in the volume-limited sample, and \(78.1\%\) and \(65.9\%\) in the paired sample. These results show that FRIIs are less frequently found in clusters, especially at high
radio luminosity, consistent with dense intracluster gas disrupting or decelerating jets and suppressing stable FRII structures. Nevertheless, once inside clusters, FRIs and FRIIs inhabit similar large-scale environments, implying that cluster-scale properties alone are unlikely to be the primary driver of the FRI/FRII dichotomy.
Read the full abstract ▾
All authors Tong Pan, Yuming Fu, H. J. A. Rottgering, J. M. G. H. J. de Jong, M. J. Hardcastle, B. Mingo, L. Clews, M. Magliocchetti, J. W. Petley, Bohan Yue
Astrophysics of Galaxies
Gaia-Sausage-Enceladus: Lithium evolution from early red-giant-branch and main-sequence stars
C. T. Nguyen, G. Cescutti, M. M. Bennedik et al. (+3 more)
The combination of data from the
Gaia satellite and large ground-based spectroscopic surveys recently lead to a milestone understanding of our
Galaxy's formation history, marked by the identification of
stellar remnants of the accreted
Gaia-Sausage-Enceladus (GSE)
dwarf galaxy. Lithium (Li) remains one of the most difficult elements to explain because of its complex behaviour over evolutionary timescales: both the Spite plateau observed in metal-poor main-sequence (MS)
stars and the recently discovered Li plateau of early red-
giant-branch (eRGB)
stars in the Milky Way challenge current
galactic chemical
evolution models. In this article, we investigate the viability of these Li-plateau features in the GSE
galaxy, using public data from current big surveys: GALAH,
Gaia-ESO, and the collective SAGA database. We present a chemical
evolution model of Li for GSE and find agreement with the observed data. We find the signature of Li plateau at low
metallicities in both eRGB and MS
stars. At higher
metallicities, we see candidates of the Li-enriched
stars that have their main contribution from nova explosions. These results reinforce the universality of the Spite plateau, and indicate that the eRGB Li plateau might also be a universal feature across different
galactic systems. A hint of low nova Li yield in GSE is suggested by our eRGB sample from GALAH. However, the lack of
stars at high
metallicities, possibly caused by the merger event, prevents a precise study of nova contributions, and we expect that upcoming data will enable a more comprehensive analysis.
Read the full abstract ▾
All authors C. T. Nguyen, G. Cescutti, M. M. Bennedik, P. Molaro, L. Magrini, A. J. Korn
High Energy Astrophysical Phenomena
Hydrodynamic model of nonthermal emission from the Fermi bubbles
V.A. Dogiel, D.O. Chernyshov, T.S. Fatekhov et al. (+2 more)
We suggest a model of
Fermi Bubbles (FBs) in the
Galactic halo of the altitude about 7-8 kpc, which is seen in non-thermal microwave and gamma-ray ranges. It was assumed that this emission is generated by relativistic electrons of
cosmic rays whose origin is still under debate. It has been assumed that the FB shell is generated in the
halo by the release of energy, generated by the routine capture of
stars at the central black hole of the
Galactic Centre (GC). In this case
cosmic ray electrons (CR) in the shells of the FBs of sufficiently high energies are generated by the standard shock acceleration. However, one of the problems of this model is that the Mach number of the FB shock is not high enough to generate the observed non-thermal radiation from the
halo. We propose an alternative model of
stochastic CR acceleration by Rayleigh-Taylor (RT) instabilities in the shell of the FB at the late stages of the
evolution of the shell in the
halo. Unlike the shock model of CR acceleration, the RT model of in-situ acceleration in the FBs does not require strong shock fronts. In our model, we derived the spectrum of RT instabilities and estimate the spectra of kinetic equations for MHD-fluctuations needed for acceleration of CRs. We assessed the time of CR electron acceleration up to TeV energies that needed to interpret the observed data of gamma-ray and microwave emission from the envelope of FBs.
Read the full abstract ▾
All authors V.A. Dogiel, D.O. Chernyshov, T.S. Fatekhov, A.M. Kiselev, C.M. Ko
Instrumentation and Methods for Astrophysics
A Wavelet-Integrated Search Pipeline for Narrowband Technosignatures in FAST Observations of 33 Exoplanet Systems
Zi-Qi Li, Jian-Kang Li, Zhe-Wei Luo et al. (+14 more)
Building on prior FAST targeted and blind SETI campaigns toward 33
exoplanet systems, we introduce a wavelet-integrated search pipeline for narrowband technosignature candidates in
radio dynamic spectra. At its core, the pipeline uses a Multi-Scale Wavelet Net (MSWNet) to produce an interpretable multi-resolution representation, followed by a lightweight parameter
estimator for endpoint localization. Rather than relying solely on hard-threshold drift searches, the pipeline reframes narrowband detection as wavelet-guided feature extraction followed by endpoint regression, morphology-aware filtering, raw-data S/N validation, and multi-beam anticoincidence veto. Applied to real FAST data, the pipeline recovers representative events from prior analyses and produces a compact set of veto-ready candidates for downstream inspection. The resulting workflow preserves interpretability, low regression complexity, and auditable threshold control, making it readily transferable to other
radio surveys and large-scale technosignature searches.
Read the full abstract ▾
All authors Zi-Qi Li, Jian-Kang Li, Zhe-Wei Luo, Chen-Xu Guan, Yu-Tong Fan, Zhen-Zhao Tao, Xiao-Hang Luan, Bo-Lun Huang, Yu Hu, Peng-Yu Li, Pu-Fan Liu, Kang Jiao, Tong-Jie Zhang, Hai-Yan Zhang, Peng Jiang, Rui Li, Liang Gao
Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc
The imprints of the instantaneous appearance of a conformal Killing vector field on the evolution of self-gravitating fluid spheres
L. Herrera, A. Di Prisco and J. Ospino
We study the influence of the instantaneous appearance of a conformal Killing vector (CKV) in self-gravitating fluid spheres during their
evolution. For doing that we introduce a tensor variable whose time dependence allows the existence of a CKV for a given value of the time-like coordinate. We consider adiabatic and dissipative fluids. The analysis of different relevant physical variables in this process provides a smoking gun signature from the emergence of CKV at some point of the
evolution. Prospective applications of these results, as well as open questions and pending issues related to this problem, are discussed.
Read the full abstract ▾
Earth and Planetary Astrophysics
New substellar candidates identified through deep learning in the F150 sample of the large-scale SHINE direct imaging survey
Carles Cantero Mitjans, Mariam Sabalbal, Olivier Absil et al. (+3 more)
Context. The SPHERE High-contrast Imaging survey for
Exoplanets (SHINE) represents one of the largest direct imaging campaigns, targeting over 400 young, nearby
stars with the goal of detecting and characterizing
giant exoplanets and brown
dwarfs. This
dataset offers a unique opportunity to revisit observations using modern, data-driven approaches, potentially uncovering new substellar candidates that may have been overlooked by classical analysis techniques. Aims. Our study focuses on reprocessing and reanalyzing the so-called F150 sample, a well-defined subset of 150 main-sequence
stars within 100 pc observed in the H-band with VLT/SPHERE as part of the SHINE survey. Methods. We apply NA-SODINN, a supervised deep learning model specifically tailored for detecting faint planetary signals in angular differential imaging (ADI) sequences. Designed to model local noise properties and capture spatial context, NA-SODINN is effective at distinguishing real companions from residual speckle noise. To translate the model's pixel-wise confidence maps into actionable detections, we introduce a novel F1-score-based thresholding strategy. This principled approach balances sensitivity and specificity, addressing a key limitation in current deep learning-based methods. Results. NA-SODINN recovers all known companions and some of the debris disks in the F150 sample, and identifies 13 new substellar candidates not reported in previous studies: ten detected in both the H2 and H3 bands, and three in only one band. For the ten sources detected in both bands, we use the H2-H3 color-magnitude diagram to perform a first assessment of their nature. Based on this analysis, we identify two ambiguous cases and three photometrically promising candidates. However, in light of the currently available multi-epoch SPHERE data, only the candidate around Smethells 20 remains a strong target for follow-up.
Read the full abstract ▾
All authors Carles Cantero Mitjans, Mariam Sabalbal, Olivier Absil, Marc Van Droogenbroeck, Damien Ségransan, Philippe Delorme
Solar and Stellar Astrophysics
The s- and r- components of the proto-solar composition
N. Prantzos, S. Cristallo and C. Abia
We present a brief overview of the various methods proposed to derive the s- and r-components of the proto-
solar chemical composition and we discuss some recent developments in the field, including the impact of rotating massive
stars,
nuclear measurements, physics of low mass asymptotic
giant branch
stars, isotopic composition of presolar SiC grains and new derivations.
Read the full abstract ▾
Astrophysics of Galaxies
The FAST Hundred-Deg$^2$ HI Deep (HD$^2$) Survey: Early Results from the Pilot Survey
Chen Xu, Yingjie Jing, Jie Wang et al. (+26 more)
The Hundred-deg$^2$ HI Deep (HD$^2$) survey carried out with the Five-hundred-meter Aperture Spherical
Telescope (FAST) is planned to map a contiguous region within the DESI DR1 footprint, achieving an effective integration time of 20 minutes for each pointing and a uniform detection sensitivity of 0.28 mJy beam$^{-1}$ at 4.8 km s$^{-1}$ resolution. We present early results from the pilot HD$^2$ survey: a 10 deg$^2$ field overlapping with HSC-SSP and the DESI EDR SV3, observed with an integration time of 7.3 minutes per beam and the rms of 0.45 mJy beam$^{-1}$ at 4.8 km s$^{-1}$ resolution. We identify 339 HI sources at $z<0.09$, corresponding to $\sim$34 detections per deg$^2$, nearly six times higher than the detection rate of the wide-field surveys. Optical counterparts are primarily identified using DESI
redshifts, yielding a matching rate and correctness exceeding 90% for
galaxies with $r<19.5$ mag, a substantial improvement over SDSS. Under the constraint of $r < 17.8$ mag and $0.01 < z < 0.05$, nearly 50% of
galaxies in the DESI BGS samples have HI detections in this pilot survey. The optical properties of these HI-detected
galaxies span nearly the entire parameter range of the DESI sample. The gas fraction scaling relations versus
stellar mass,
stellar mass surface density, NUV-r, and specific
star formation rate are consistent with previous surveys, e.g., ALFALFA, DINGO, and xGASS. These results justify the feasibility of the full HD$^2$ survey, which will build a high-completeness HI census over a contiguous area to probe the cold gas scaling relations of
galaxies over different scales.
Read the full abstract ▾
All authors Chen Xu, Yingjie Jing, Jie Wang, Hu Zou, Wei Du, Niankun Yu, Hong Guo, Zerui Liu, Qingze Chen, Tiantian Liang, Zhipeng Hou, Yiwei Xu, Xiao Li, Hui-Jie Hu, Ziming Liu, Pinsong Zhao, Taotao Fang, Liang Gao, Qi Guo, Qiusheng Gu, Zhen Jiang, Xi Kang, Xu Kong, Cheng Li, Jun Pan, Tao Wang, Yanrui Zhou, Wenting Wang, Jing Wang
Instrumentation and Methods for Astrophysics
HiFAST: An HI data calibration and imaging pipeline for the FAST IV: The stray-radiation correction
Qingze Chen, Jie Wang, Yingjie Jing et al. (+12 more)
Stray radiation is a considerable challenge for
radio telescopes, requiring careful assessment due to its effects. This is crucial when the strong background flux from side lobes significantly affects the total flux, especially for extended sources. In this study, we introduced the beam pattern of the L-band receiver on the Five-hundred-meter Aperture Spherical
Telescope (FAST), covering various frequencies based on recent observations. We discovered that the main beam efficiency of all beams exceeds 90% throughout the L band frequencies, with efficiency decreasing slowly as frequency increases. Subsequently, we developed a module to mitigate stray radiation effects, incorporating it into FAST's standard \HI data reduction process, referred to as HiFAST. Our analysis shows that side lobe flux's influence, particularly for extended sources with significant surface density gradients, necessitates detailed evaluation. Corrections for the extended M33
galaxy can reach up to 20%. Moreover, the pattern data presented here is vital for studying HI intensity maps at high
redshift. The module, along with HiFAST and beam pattern data across 15 frequency bins, can be accessed at https://hifast.readthedocs.io. The
datasets of beam pattern presented in this paper, are openly available at https://doi.org/10.57760/sciencedb.j00113.00266 (https://www.scidb.cn/s/bqQRNv).
Read the full abstract ▾
All authors Qingze Chen, Jie Wang, Yingjie Jing, Ligang Hou, Chen Xu, Tiantian Liang, Xuyang Gao, Jinlin Han, Ziming Liu, Bin Liu, Chuanpeng Zhang, Hengqian Gan, Ming Zhu, Yan Zhu, Peng Jiang
Earth and Planetary Astrophysics
Modeling (Sub-)millimeter Scattering Properties of Fractal and Consolidated Porous Particles: Applications to Protoplanetary Disks
Gonzalo Vargas, Daniel Guirado, Carlos Carrasco-Gonzalez et al. (+5 more)
We perform light-scattering numerical simulations for two
dust populations: (i) consolidated porous particles computed with the discrete dipole approximation (ADDA) and (ii) highly porous aggregate models, including fractal and hierarchical aggregates, computed with the multiple-sphere T-
matrix method (MSTM). Using DSHARP optical constants, we compute scattering
matrices, cross sections, and effective albedo omega_eff for a size distribution n(a) proportional to a^q, with q = -3.5, amin = 0.1 micron, and ten wavelengths from 0.87 to 10 mm. We find that increasing porosity strengthens forward scattering and enhances polarization near theta approximately 90 degrees. For compact spheres, P(90 degrees) times omega_eff peaks near amax approximately lambda divided by 2 pi and then declines, whereas porous particles show a broader peak extending to larger sizes, keeping polarization-based constraints compatible with amax approximately 1 mm. Porosity also lowers kappa_abs at fixed
dust mass relative to compact spheres, implying larger inferred
dust masses for a given continuum flux.
Read the full abstract ▾
All authors Gonzalo Vargas, Daniel Guirado, Carlos Carrasco-Gonzalez, Olga Munoz, Maxim A. Yurkin, Enrique Macias, Jesus M. Jaquez-Dominguez, Francisco J. Garcia-Izquierdo
Astrophysics of Galaxies
Gas Fraction and Depletion Time Drive the Main-Sequence Scatter in Massive Galaxies at $z\sim1.5$
Daichi Kashino, Boris S. Kalita, John D. Silverman et al. (+8 more)
We present ALMA Band 7
dust continuum observations of 57 massive ($M_\ast \gtrsim 10^{10.8}~M_\odot$)
star-forming
galaxies at $1.45<z<1.70$, selected from the FMOS-COSMOS survey to provide a homogeneous sample near the main sequence (MS) at
cosmic noon. The observations are sufficiently deep to yield $>3\sigma$ detections for 55
galaxies. Combining the ALMA data with multiwavelength photometry, we reliably derive
dust masses and infer molecular gas masses using
metallicity-dependent gas-to-
dust ratios estimated from individual
metallicity measurements. The derived molecular gas mass ratio spans $\mu_\mathrm{gas} = M_\mathrm{gas}/M_\ast=0.11\text{--}2.8$, with a median value of 0.65, corresponding to gas reservoirs more than an order of magnitude larger than in local
galaxies at fixed
stellar mass. The integrated Schmidt–Kennicutt relation is consistent with previous measurements over $z=0\text{--}2$. Across the MS, both molecular gas mass ratio and
star formation efficiency scale approximately as $(\mathrm{sSFR}/\mathrm{sSFR}_\mathrm{MS})^{0.5}$, indicating that the MS scatter is driven nearly equally by variations in gas content and depletion time. The intrinsic scatter of $0.19$~dex suggests additional
galaxy-to-
galaxy diversity in
star formation efficiency. Our results provide a controlled test of the unified gas scaling framework in the massive regime at $z\sim1.5$, demonstrating that the fundamental regulation of
star formation through coupled modulation of gas supply and efficiency is already in place at
cosmic noon.
Read the full abstract ▾
All authors Daichi Kashino, Boris S. Kalita, John D. Silverman, Tomoko L. Suzuki, Annagrazia Puglisi, Alvio Renzini, Emanuele Daddi, Giulia Rodighiero, Francesco Sinigaglia, Xuheng Ding, David B. Sanders
High Energy Astrophysical Phenomena
Long-term optical and near-infrared photometric evolution of SN 2019vxm, an interacting Type IIn supernova
Klára Lelkes, László Molnár, József Vinkó et al. (+12 more)
The diversity of Type IIn
supernovae is largely driven by the properties of the circumstellar material (CSM) they explode into. We examine the temporal
evolution of SN 2019vxm, an interacting
supernova that belongs to the class of long-lasting Type IIn events, using multicolor photometry spanning the ultraviolet, optical and near-infrared wavelengths, including over 650 days of optical and 1500 days of IR coverage. The
evolution of the spectral energy distribution and bolometric luminosity, as well as the effective temperature and radius of the photosphere, indicates that the
supernova was initially surrounded by an optically thick CSM, which was heated and pushed outward by the forward shock of the impacting ejecta. About 80-100 days after the explosion the forward shock and the photosphere decouples, and we observe the receding photosphere of the H-recombination front within the now thinned CSM. Near-IR measurements reveal long-lasting, slowly cooling emission from circumstellar
dust around SN 2019vxm and an IR rebrightening about one year after explosion, which we tentatively identify as a signature of an outer CSM region. We find that due to the moving photosphere and the transition from optically thick to partially thin inner CSM, modeling the explosion and subsequent interaction of the ejecta with the CSM to infer progenitor and CSM masses faces difficulties. Nevertheless, the inferred high masses and extremely high mass-loss rates point to a massive progenitor undergoing intense pre-
supernova mass loss.
Read the full abstract ▾
All authors Klára Lelkes, László Molnár, József Vinkó, Attila Bódi, Zsófia Bora, Borbála Cseh, Csilla Kalup, Réka Könyves-Tóth, Levente Kriskovics, András Ordasi, András Pál, Bálint Seli, Zsófia Marianna Szabó, Róbert Szakáts, Krisztián Vida
Solar and Stellar Astrophysics
Investigation of the Two-Dimensional Velocity Field of the Large-Scale Coronal Wave from September 6, 2011 using the SOLERwave Tool
Markus Baumgartner-Steinleitner, Astrid M. Veronig, Karin Dissauer et al. (+1 more)
We investigate the two-dimensional velocity field of the fast and complex large-scale coronal wave observed on September 6, 2011. We use both a classical perturbation profile approach and the newly developed multi-sector method of the SOLERwave tool, using a Huygens-plotting-based approach. The multi-sector method utilizes perturbation profiles derived in multiple directions (sectors) to determine the location of the wavefront at a given time. The two-dimensional velocity vector at each point along the wavefront is derived by identifying the point closest to it along the wavefront observed one time step earlier and dividing the distance between the two points along the
solar surface by the time difference between the observations. For the event under study the resulting two-dimensional velocity field shows a significant difference between the northward traveling and the northwest ward traveling part of the wave front of over 40%, in the range of 750 to 1500 km/s. To determine the cause of this difference in speed, we investigate the coronal structures, the photospheric
magnetic field distribution and the Alfvén speed derived from a steady-state coronal magneto hydro dynamic (MHD) solution along different propagation directions of the wave. We find the large difference in magnetosonic speed found in the investigated sector as the most likely explanation for the velocity difference.
Read the full abstract ▾
All authors Markus Baumgartner-Steinleitner, Astrid M. Veronig, Karin Dissauer, Jens Pomoell
Astrophysics of Galaxies
Multi-layered model-based characterisation of the local-Universe galaxy data from the GAMA survey
Fan Dai, Ranjan Maitra and Ivan K. Baldry
Understanding the formation and
evolution of
galaxy populations requires robust classification and characterisation techniques that jointly account for internal
galaxy properties and environment. We analyse $5,306$
galaxies from the
Galaxy And Mass Assembly (GAMA) survey, described by
stellar mass, specific
star formation rate, $u-r$ colour, half-light radius, Sérsic index, and a combined environmental measure given by the optimal density. Unlike distance-based unsupervised clustering methods, our framework provides a probabilistic characterisation of
galaxy populations, accommodates heavy-tailed feature distributions, and captures dependence among observables through latent factors. We model the sample using a $t$-mixture of factor analysers with group-specific latent structures (M$t$FAD), and then apply model-estimated overlap-based syncytial clustering (MOBSynC) to merge weakly separated groups and recover higher-level population structure. The first stage identifies eight simple clusters. The third and the fourth groups lie on the red, low-
star-forming sequence and correspond to environmentally quenched and mass-quenched systems, respectively, while the sixth group traces the massive end of the
star-forming sequence, and the seventh group appears to represent a more heterogeneous population that may include transition objects. The remaining groups populate the low- to intermediate-mass blue sequence, including both compact and more extended
star-forming
galaxies. The second MOBSynC stage merges the simple clusters into two compound groups: a red sequence formed by the third and the fourth groups, and the rest merging to form a broad blue sequence. Our results show that the familiar red-blue bimodality of local
galaxies contains additional physically meaningful substructure linked to quenching pathway, morphology, and environment.
Read the full abstract ▾
Instrumentation and Methods for Astrophysics
A Markov-Chain-Monte-Carlo-based Hybrid Noise Inference for Continuous Wavelet Power Spectra: with Applications to Solar and Stellar Oscillatory Signals
Song Feng, Lin Li and Ding Yuan
Detecting oscillations in
solar and
stellar time series is complicated by non-stationary red noise and evolving background emission. Methods based on detrending and AR(1)-based wavelet analysis can introduce spurious periodicities and do not adequately describe time-dependent backgrounds. We develop a
Bayesian approach that combines the continuous wavelet transform with MCMC sampling to infer a time-dependent background spectrum. The background is represented by a power-law plus white-noise component, with parameters allowed to vary smoothly in time, so that significance levels can be evaluated locally without explicit detrending. Tests with synthetic data show that injected oscillations are recovered reliably, while false detections are suppressed in pure-noise cases. Using a frequency-domain signal-to-noise ratio (S/N), we find that oscillations can be identified robustly when the S/N is greater than or equal to 2 under mixed noise conditions. The detectable period range is limited by wavelet resolution, from about 3-4 sampling intervals up to roughly one-quarter of the total duration. Application to GOES soft X-ray
flare observations shows that the method isolates quasi-periodic oscillations with improved temporal localization compared to standard wavelet and
Fourier-based approaches. Meanwhile, this behavior is consistent across a range of noise conditions and signal morphologies.
Read the full abstract ▾
Earth and Planetary Astrophysics
51 Peg b revisited with VLT/CRIRES+. Constraints on atmospheric thermal structure, chemical composition, and an alternative orbital solution
D. Cont, L. Nortmann, F. Lesjak et al. (+18 more)
So far, the atmospheres of non-transiting
exoplanets remain poorly explored, and the potential of high-resolution spectroscopy for determining key planetary parameters beyond their atmospheric properties has not been fully exploited. We obtained high-resolution emission spectra of the non-transiting hot Jupiter 51 Peg b with VLT/CRIRES+ to study its atmospheric thermochemical and dynamical structure and derive additional planetary parameters from the Doppler shift of its spectral lines. Using the cross-correlation technique, we confirmed the spectral signature of H$_2$O in the planetary emission spectrum and a non-inverted atmospheric temperature profile. An indication was also found for the presence of atmospheric CO. The atmospheric chemical and thermal conditions were quantitatively constrained by use of a
Bayesian retrieval framework, which yielded a high
metallicity value ($2.63_{-0.93}^{+1.00}$ dex) suggestive of chemical quenching, a
solar C/O ratio ($0.54_{-0.23}^{+0.18}$), and a temperature profile in the upper atmosphere in line with the expected planetary
equilibrium temperature. Moreover, we measured an excess of spectral line broadening. The planetary signal was recovered at an orbital semi-amplitude of $102.8_{-9.1}^{+8.3}$ km s$^{-1}$, differing from previous high-resolution measurements. From the obtained orbital semi-amplitude, we further derived the surface
gravity ($3.15 \pm 0.12$ log cgs), mass ($0.61_{-0.05}^{+0.06}$ $M_\mathrm{Jup}$), and orbital inclination ($49.8_{-5.7}^{+5.8}$ deg) of 51 Peg b. The mass and inclination values differ from those reported in earlier works. Overall, this study provides new constraints on the thermochemical and dynamical properties of 51 Peg b's atmosphere and demonstrates the potential of high-resolution emission spectroscopy for measuring parameters related to the planetary orbital motion.
Read the full abstract ▾
All authors D. Cont, L. Nortmann, F. Lesjak, U. Seemann, L. D. Nielsen, B. Wechselberger, F. Yan, S. Liu, A. Reiners, A. Lavail, D. Shulyak, A. Hatzes, N. Piskunov, L. Boldt-Christmas, S. Czesla, E. W. Guenther, O. Kochukhov, T. Marquart, E. Nagel, A. D. Rains, M. Rengel