Cosmology and Nongalactic Astrophysics
A sub-ppm upper limit on the cosmological variations of the fine structure constant alpha
S. Muller, A. Beelen, M. Guelin et al. (+9 more)
Absorption spectroscopy toward high-
redshift quasars provides strong constraints on the putative variation of fundamental constants of physics on cosmological time scales. The submillimeter ground-state transitions of methylidyne (CH) and water (H2O), both molecules widespread and coeval in the interstellar medium, provide a sensitive test for variations of alpha, the fine structure constant, and mu, the
proton-to-electron mass ratio, taking advantage of the unmatched spectral resolution and frequency reliability of
radio techniques. We used ALMA simultaneous observations of the two species to constrain any velocity offset between their absorption profiles toward the
radio-bright lensed
quasars PKS1830-211 (z_abs=0.88582) and B0218+357 (z_abs=0.68466). Our observational setup minimizes instrumental errors and known sources of systematics, such as time variability of the absorption profile and frequency-dependent morphology of the background
quasar. The excellent correlation between CH and H2O opacities, the large number of individual narrow velocity components, and the number of independent spectra obtained due to the intrinsic time variability of the absorption profiles ensure that even the chemical segregation bias is minimized. We obtained bulk velocity shifts delta_v = -0.048 pm 0.028 km/s and -0.13 pm 0.14 km/s (1 sigma confidence level) between CH and H2O in the direction of PKS1830-211(NE) and B0218+357(SW), respectively. These values convert into the 3sigma upper limits |Delta_alpha/alpha| < 0.55 ppm and 1.5 ppm, respectively, taking into account the independent upper limits on |Delta_mu/mu| previously obtained for these systems. These constraints on |Delta_alpha/alpha|, at look-back times of about half the present age of the Universe, are two to four times deeper than previous constraints on any other single high-z system.
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All authors S. Muller, A. Beelen, M. Guelin, J. H. Black, F. Combes, H. L. Bethlem, M. Gerin, C. Henkel, K. M. Menten, M.T. Murphy, W. Ubachs, N. Wozny
Instrumentation and Methods for Astrophysics
QUIJOTE-TFGI polarization calibration – Ground characterization and on-sky validation with Tau A and the Moon
Alessandro Fasano, Mateo Fernández-Torreiro, Guillermo Pascual-Cisneros et al. (+6 more)
Our objective is to characterize the QUIJOTE Thirty and Forty GHz instrument (TFGI), calibrate it with a reference calibration signal on the ground, compare our results with on-sky calibration based on bright sources, and study the stability of the calibration parameters over time. First, from the ground, we fit the data using a reference calibration signal (a diode) introduced to resolve degeneracies among the various instrument angles. Finally, we utilize on-sky observations of Tau A and the Moon to validate the results. By creating calibration
datasets obtained with the reference diode, we evaluate the data quality and quantify phase switch errors to account for the fine polarization response. We also utilize Tau A and Moon observations to calibrate the system's response and stability over time. In addition, we calculate the refraction index of the Moon to be $n_{Moon}$ = 1.209 $\pm$ 0.007 (stat) $\pm$ 0.005 (sys) at 31 GHz under smooth-surface assumption. The results from fitting the instrument phase-switch error angle align with 0 deg at 2$\sigma$ precision, indicating that no further correction is required within a few percent precision. The calibrations with astrophysical sources (Tau A and the Moon) yield consistent results that constrain the polarization angle and responsivity. The polarization efficiency aligns well with ground measurements and the Tau A characterization, whereas the Moon-based calibration is more affected by systematics. We find hints of responsivity variations over time, although the relative responsivity between channels is found to remain stable. In the future, we conclude that installing a live calibrator will enhance performance by continuously monitoring responsivity and, in turn, improving the mitigation of systematic effects.
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All authors Alessandro Fasano, Mateo Fernández-Torreiro, Guillermo Pascual-Cisneros, Roger John Hoyland, Francisco Javier Casas-Reinares, Ricardo Tanausú Génova-Santos, Michael William Peel, Rafael Rebolo-López, José Alberto Rubiño-Martín
Earth and Planetary Astrophysics
The Role of Self-Gravity in Debris Disk Warp Formation: The Case of HD 110058
Gang Zhao, Su Wang and Jiangpei Dou
We investigate the crucial role of self-
gravity in the formation of warps in debris disks, focusing on the HD 110058 system as an example. Using advanced, GPU-accelerated $N$-body simulations, we model the gravitational dynamics of a massive planetesimal disk perturbed by an inclined, inner
planet. Our simulations reveal that self-
gravity fundamentally alters the disk's
evolution compared to massless models. It enforces a coherent, semi-rigid precession of the disk and enables the rapid formation of a global warp structure within 0.5 Myr. The warp angle undergoes a damped oscillation, eventually settling into a quasi-
equilibrium state. By generating synthetic scattered-light images, we demonstrate that our model successfully reproduces the observed S-shaped warp morphology of the debris disk in HD 110058, supporting the existence of an unseen
planet. Furthermore, we derive an empirical relationship that connects the
equilibrium warp angle to the physical parameters of the disk and the
planet. Applying this relation to HD 110058, we constrain its disk mass to be likely less than 1,000 $M_\oplus$, offering a new dynamical perspective on the debris disk mass problem.
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Astrophysics of Galaxies
Surveying Galaxy Clusters (in formation) in the Distant Universe
J.M. Pérez-Martínez, H. Dannerbauer, E. van Kampen et al. (+8 more)
Present-day
galaxy clusters are the largest virialized structures in the Universe, yet their early assembly remains poorly understood. At z$>$2, clusters in formation span tens of Mpc and host gas-rich,
dust-obscured
galaxies embedded in extended, low-surface-brightness gaseous environments. Current (sub-)millimeter facilities lack the mapping speed, sensitivity, and contiguous field of view needed to trace the cold gas and
dust driving rapid
galaxy growth across such scales. A future large single-dish observatory with degree-scale coverage, broad spectral access, and high-multiplex capability would enable comprehensive and uniform mapping of entire protoclusters, revealing where
star formation is triggered or quenched, and quantifying the cold gas budget, thus providing information on gas cooling within protocluster environments. In synergy with wide-sky optical/NIR surveys such as Euclid, LSST, and Roman, this facility would provide the missing multi-scale and multiphase submillimeter view needed to uncover how the
stellar, gaseous, and dark-matter components assemble in protoclusters, completing our view of early structure formation.
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All authors J.M. Pérez-Martínez, H. Dannerbauer, E. van Kampen, C. Cicone, E. Hatziminaoglou, L. Bonavera, L. Di Mascolo, J. González-Nuevo, F. Guglielmetti, A. Pensabene, J. van Marrewijk
High Energy Astrophysical Phenomena
INTEGRAL IBIS catalog of magnetar bursts
Dominik P. Pacholski, Sandro Mereghetti and Martin Topinka
One of the distinctive properties of magnetars, young
neutron stars powered mainly by
magnetic energy, is the emission of short ($\lesssim$1 s) bursts of hard X-rays. Such bursts have been observed in nearly all the known magnetars, although at different and time-variable rates of occurrence. In the last two decades, the INTEGRAL satellite has extensively covered with good imaging capabilities the
Galactic plane, where most magnetars reside. We present the results of a comprehensive search for magnetar bursts in more than twenty years of archival data of the INTEGRAL IBIS instrument (15 keV - 1 MeV). This led to the detection of 1349 bursts with 30-150 keV fluence in the $\sim2\times10^{-9} - 3\times10^{-6}$ erg cm$^{-2}$ range from 21 of the 34 examined magnetars and candidate magnetars with well known positions. The durations of the bursts, in terms of $T_{90}$, follow a lognormal distribution centered at $\sim0.1$ s. Most of the detected bursts originated from three particularly active sources: 1E 1547-5408, SGR 1806-20, and SGR 1935+2154. The integral distributions of their burst fluences follow power laws with slopes $\beta$= 0.76$\pm$0.04, 0.95$\pm$0.06, and 0.92$\pm$0.10, respectively. The burst spectra are generally well fit with an exponentially cut-off power law with peak energy $E_{peak}$ in the range $\sim20-60$ keV for SGR 1806-20 and SGR 1935+2154, while the bursts of 1E 1547-5408 are slightly harder ($E_{peak}\sim35-100$ keV). A significant anti-correlation between $E_{peak}$ and fluence is found for SGR 1806-20, which provided the largest number of bursts among the sources of our sample.
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Solar and Stellar Astrophysics
Formation of a Magnetic Flux Rope Prior to the Eruption: Insight from a Radiative MHD Simulation of Active Region Emergence
Can Wang, Takaaki Yokoyama, Feng Chen et al. (+3 more)
Magnetic flux ropes (MFRs) are fundamental
magnetic structures in
solar eruptions, whose formation is generally attributed to (1) the emergence of subsurface flux tubes or (2) flux cancellation driven by photospheric horizontal flows and
magnetic reconnection. Both mechanisms can operate simultaneously during active region
evolution, making their relative contributions challenging to quantify. Here, we analyze the formation of a flux rope in a MURaM radiative magnetohydrodynamic (RMHD) simulation, which formed and evolved for approximately three hours before an M-class
flare. The formation process is quantified by
magnetic helicity flux, which drives the non-potential
evolution of
magnetic field, with its advection and shear terms on the photosphere corresponding to the emergence and photospheric horizontal flows, respectively. Examining the helicity injected into the flux rope through the photosphere, we find both terms increase significantly as the eruption approaches, with the shear term prevailing overall. Height-dependent analysis of helicity flux, together with
magnetic field and velocity distributions, further reveals a gradual transition from the shear to the advection term with an increasing altitude, which is driven by
magnetic reconnection above the photosphere. Our results provide quantitative evidence that flux cancellation governs flux rope formation, arising naturally from
magnetic field reorganization during active region
evolution: as flux emergence transports
magnetic flux upward, photospheric shearing motions adjust
magnetic field and inject helicity into
solar atmosphere, and
magnetic reconnection ultimately assembles the main body of flux ropes.
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All authors Can Wang, Takaaki Yokoyama, Feng Chen, Chen Xing, Mingde Ding, Zekun Lu
Instrumentation and Methods for Astrophysics
Development of a Central Trigger Processor board for the Advanced SiPM based camera of the CTA Large-Sized Telescopes
A. Pérez-Aguilera, M. Molina-Delicado, T. Dietrich et al. (+8 more)
We present ongoing work on the Central Trigger Processor board (CTPb), a trigger subsystem for the future advanced SiPM-based Large-Sized
Telescope (LST) camera of the Cherenkov
Telescope Array Observatory (CTAO). The camera will implement a fully digital trigger, exploiting the increased resolution to improve discrimination of low-energy $\gamma$-ray events from Night Sky Background noise. This approach aims to enhance
telescope sensitivity while satisfying strict timing and data rate constraints. We describe the CTPb conceptual design and report initial results from hardware prototypes under evaluation within this next-generation trigger architecture.
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All authors A. Pérez-Aguilera, M. Molina-Delicado, T. Dietrich, L.A. Tejedor, J.A. Barrio, A. Upegui, Q. Berthet, J. Buces, D. Nieto, D. Martín-Domínguez, T. Miener
Cosmology and Nongalactic Astrophysics
Invisible gravitons and large-scale magnetism
Massimo Giovannini
The large-scale limits on the relic signals of gravitational radiation complement the bounds coming from the interferometric detectors (in the audio band) and from the
pulsar timing arrays (in the nHz range). Within this inclusive perspective the spectral energy density of the gravitons is sharply suppressed in the aHz region even though the high frequency signal can be comparatively much larger both in the kHz and GHz domains. For there are no direct tests on the expansion rate prior to the formation of the light
nuclei, a modified postinflationary timeline affects the total number of $e$-folds and additionally suppresses the tensor to scalar ratio by making the relic signals effectively invisible in the aHz range. The expansion rate prior to nucleosynthesis is further bounded by the
evolution of the hypercharge field and the large-scale magnetism also constrains the decelerated expansion rate. The magnetogenesis requirements are compatible with a potentially detectable spectral energy density of the relic gravitons between the MHz and the THz while the tensor to scalar ratio remains suppressed in the aHz region. A maximum of the spectral energy density of the gravitons in the audio domain leads instead to a larger
magnetic field when the scale of the gravitational collapse of the protogalaxy (of the order of the Mpc) gets comparable with the Hubble radius before equality. Along a converse viewpoint the results obtained here imply that a long decelerated stage expanding faster than radiation does not affect the high frequency range but reduces the effective number of $e$-folds by so enhancing the tensor to scalar ratio, possibly beyond its observational limit.
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Solar and Stellar Astrophysics
Comparative study between low and high energy SOHO/ERNE protons in solar cycle 23
Rositsa Miteva, Susan W. Samwel and Momchil Dechev
We present a comparison between low and high energy
solar energetic
protons (SEPs) as observed by the SOHO/ERNE high energy detector in
solar cycle (SC) 23. Observed and corrected peak
proton intensities are used in the analyses. The linear correlations are calculated between the
proton intensity and the soft X-ray class of
solar flares (SFs) on one side and the projected speed of coronal mass ejections (CMEs), on another. The energy trends of these correlations are compared with previous reports.
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Solar and Stellar Astrophysics
A Bridge between Young Stars Formed by Gravitational Interaction
Youngwoo Choi, Woojin Kwon, Leslie W. Looney et al. (+1 more)
The majority of
stars are born in clustered environments. In these environments, close encounters between young
stars with
planet-forming disks are expected to occur frequently. However, direct evidence of such interactions remains rare. Here, we report clear signatures of a recent dynamical interaction between the young
stellar systems L1448 IRS3A and L1448 IRS3B. Millimeter wavelength observations reveal a distinct, tidally stripped bridge between the two systems. Together with previously reported spiral arm structures at the outer edge of the IRS3A disk and at the inner and outer regions of the IRS3B disk, these features imply that the systems are undergoing a dynamical flyby. Hydrodynamical simulations reproduce these features and suggest that the closest approach occurred about 15,000 yr ago. These findings offer rare insight into how
stellar interactions can reshape disk structures and influence the formation of young multiple
stellar systems.
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All authors Youngwoo Choi, Woojin Kwon, Leslie W. Looney, John J. Tobin
Solar and Stellar Astrophysics
New Bulgarian-Austrian project 'Joint observations and investigations of solar chromospheric and coronal activity'
Rositsa Miteva, Werner Pötzi, Astrid Veronig et al. (+9 more)
We present the bilateral collaboration between Bulgarian and Austrian
solar and space weather researchers on the topic of chromospheric and coronal activity. This new project will focus, on one hand, on the technical setup and calibration of the new Rozhen chromospheric
telescope at the National Astronomical Observatory (NAO) by means of establishing optimal observational programs for different quiet-Sun and activity phenomena, automating the data collection and storage, implementing machine/deep learning models for feature recognition. The second aim is to carry out joint scientific analyses of
solar phenomena using observations from ground-based instruments in both countries, and supplementary spacecraft data. The successful implementation of
solar monitoring at NAO-Rozhen will facilitate the overall visibility of the Bulgarian instrument and generate interest towards astronomy and
solar physics not only for PhD students and young scientists but also for the general public.
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All authors Rositsa Miteva, Werner Pötzi, Astrid Veronig, Kamen Kozarev, Momchil Dechev, Robert Jarolim, Mohamed Nedal, Nikola Petrov, Stefan Purkhart, Christoph Schirninger, Tsvetan Tsvetkov, Yovelina Zinkova
Astrophysics of Galaxies
Connecting galaxies with their haloes – from parsec to Mpc scales
K. Fahrion, J. van de Sande, K. R. Akhil et al. (+12 more)
Galaxy evolution is driven by processes occurring across a wide range of scales, from
star formation within
giant molecular clouds (parsec scales) to
outflows and secular
evolution across entire
galaxies (kpc scales), and the interplay between
galaxies, their dark matter
haloes, and large-scale structures (Mpc scales). Connecting the distribution of baryonic matter and energy across these scales will remain one of the key challenges for both theoretical and observational astrophysics in the coming decade. A major development towards meeting this challenge has been the growing ability to obtain highly spatially resolved (parsec-scale) integral-field spectroscopic observations (e.g. with VLT/MUSE), as well as to probe the extremely low-surface brightness outskirts of
galaxies at large radii and high vertical scale heights. To combine the two regimes, we need a paradigm shift in the way we do spectroscopy on
galaxies, especially considering the ongoing and future photometric surveys. The next decade will also bring a revolution in extensive photometric surveys of large areas of the sky, uncovering low surface brightness features around nearby
galaxies. However, to fully understand the processes that connect
galaxies to their
haloes, shape low surface brightness features, and drive secular
evolution, spatially resolved spectroscopy will be essential. Here, we outline the need for wide-field spectroscopic observations of statistically significant samples of nearby
galaxies and highlight the key questions that can only be addressed with such data
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All authors K. Fahrion, J. van de Sande, K. R. Akhil, M. A. Beasley, F. Belfiore, M. L. L. Dantas, P. K. Das, E. Emsellem, J. Hartke, M. Hilker, A. Monreal-Ibero, A. Prieto, M. Raouf, S. Thater, I. Zinchenko
Instrumentation and Methods for Astrophysics
The ORCA-TWIN qCMOS Experiment I. Science case and commissioning at Calar Alto Observatory
Martin M. Roth, Pasko Roje, Stella Vjesnica et al. (+18 more)
We describe a pilot study to explore a new generation of fast and low noise CMOS image sensors for time domain astronomy, using two remote
telescopes with a baseline of 1635 km. The experiment involves direct imaging with novel qCMOS image sensor technology that combines fast readout with sub-electron readout noise. Moreover, synchronized observations from two remote
telescope sites will be used to explore new approaches for measuring
Solar System bodies, precision
stellar photometry, and speckle imaging. A fast-track installation of an ORCA-Quest2 camera at the Calar Alto Observatory 1.23m
telescope has demonstrated the potential of the qCMOS technology for time domain astronomy. Numerical simulations suggest that owing to sub-electron readout noise, qCMOS sensors outperform classical CCDs for high-cadence imaging on 1m-class
telescopes. The small penalty for post-readout binning, that is almost insignificant in comparison to higher readout noise detectors, opens interesting applications for scene-dependent data processing in direct imaging, and potentially even for spectroscopy.
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All authors Martin M. Roth, Pasko Roje, Stella Vjesnica, Stefan Cikota, Alex J. Brown, Mike Kretlow, Marco Azzaro, Santiago Reinhart, Jesus Aceituno, Harry Dawson, Carsten Denker, Torsten Enßlin, Stephan Geier, Thomas Granzer, Thomas Kupfer, Gianluca Li Causi, Samaya Nissanke, Jose Luis Ortiz, Fernando Pedichini, Katja Poppenhäger, Axel Schwope
Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph
Cosmological Bounds on Scotogenic Model with Asymmetric Mediator
Kento Asai, Seishi Enomoto, Takuya Hirose et al. (+1 more)
We study cosmological constraints on the asymmetric mediator scenario, a variant of the scotogenic model that addresses the origins of
neutrino masses, dark matter (DM), and the
baryon asymmetry. An SU(2)$_L$ doublet scalar $\eta$ mediates between the visible and dark sectors, while a singlet scalar $\sigma$ serves as the DM candidate. We evaluate the DM relic abundance by solving the Boltzmann equations including $\eta$ decay and scattering processes prior to the freeze-out of the $\eta$ asymmetry, and show Big Bang nucleosynthesis constraints from late-time $\eta$ decays. Combining the DM abundance and BBN bounds, we find the favored parameter space of this model, for instance, the mediator masses of $m_\eta \lesssim \mathcal{O}(10)$ TeV.
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All authors Kento Asai, Seishi Enomoto, Takuya Hirose, Masato Yamanaka
Earth and Planetary Astrophysics
A Possible Indication of Metallic Iron in White Dwarf Dusty Disks from their "Dirtiness"
Ayaka Okuya, Satoshi Okuzumi, Aki Takigawa et al. (+1 more)
Polluted white
dwarfs provide unique constraints on the elemental compositions of planetary bodies. The
tidal disruption of accreting bodies is thought to form circumstellar dusty disks, whose emission spectra could offer additional insights into the mineral phases of the accreted solid material. Silicates are detected in the mid-infrared spectra of several disks, but do not fully account for the near-infrared excess in the disks' spectra. Conductive materials, such as metallic iron, are potential sources of near-infrared emissivity. We investigate the role of metallic iron within silicate
dust in the observed spectra of the white
dwarfs G29-38 and GD56. Using thermal emission spectra calculations, we analyze the abundance of metallic iron in the
dust and the disk structure parameters that best fit the observed spectra. We find that metallic-iron-bearing
dust enhances the near-infrared opacity, thereby providing a better fit to the G29-38 spectrum for various silicate compositions than metallic-iron-free
dust. The best-fit metal-to-silicate mixing ratio is approximately unity, and for Mg-rich pyroxenes, this value is also consistent with G29-38's
stellar atmospheric composition within 1-$\sigma$ observational uncertainties. Based on the spectral fitting and compositional consistency, Fe-rich silicates without metallic iron cannot be ruled out. The observed GD56 spectrum also favors iron-bearing
dust. However, the large observational uncertainties of GD56's
stellar elemental abundances hinder a precise comparison between the
stellar and
dust iron abundances. Upcoming high-precision JWST observations will provide a larger sample, enabling statistical analysis of the correlation between the iron abundances in the atmospheres and circumstellar
dust of polluted white
dwarfs.
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All authors Ayaka Okuya, Satoshi Okuzumi, Aki Takigawa, Hanako Enomoto
Cosmology and Nongalactic Astrophysics
Revealing the baryon cycle in Galaxy Clusters: connecting galaxy dynamics and gas thermodynamics using (sub-)mm-wave and optical IFU surveys
Francisco M. Montenegro-Montes, Patricia Sánchez-Blázquez, Tony Mroczkowski et al. (+8 more)
Observations in the visible and near infrared are transforming our view of the processes affecting
galaxy evolution, much of which is dominated by interactions with the large scale environment. Yet a complete picture is missing, as no corresponding high resolution view of the warm/hot intracluster, circumgalactic, and intergalactic media exists over large areas and a comparably broad range of
redshifts. Combined with wide-field optical IFU surveys such as CATARSIS, a large diameter sub-mm
telescope with a degree-scale field of view would enable a joint view of
galaxy dynamics and gas thermodynamics, transforming our understanding of environmental processes.
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All authors Francisco M. Montenegro-Montes, Patricia Sánchez-Blázquez, Tony Mroczkowski, Armando Gil de Paz, Cristina Catalán-Torrecilla, Marie-Lou Gendron-Marsolais, Paula Macías-Pardo, Beatriz Callejas-Córdoba, Alfredo Montaña, Juan F. Macías-Pérez, Susana Planelles
Astrophysics of Galaxies
Exploring Cosmic Dawn with PANORAMIC II: Cosmic Variance and Galaxy Clustering at $z\sim10$
Andrea Weibel, Christian Kragh Jespersen, Pascal A. Oesch et al. (+10 more)
Observational campaigns with JWST have revealed a higher-than-expected abundance of UV-bright
galaxies at $z\gtrsim10$, with various proposed theoretical explanations. A powerful complementary constraint to break degeneracies between different models is
galaxy clustering. In this paper, we combine PANORAMIC pure parallel and legacy imaging along 34 independent sightlines to measure the
cosmic variance ($\sigma_{\rm CV}$) in the number counts of Lyman break
galaxies at $z\sim10$ which is directly related to their clustering strength. We find $\sigma_{\rm CV}=0.96^{+0.20}_{-0.18}$, $1.46^{+0.54}_{-0.44}$, and $1.71^{+0.72}_{-0.59}$ per NIRCam pointing ($\sim9.7\,{\rm arcmin}^2$, $\lesssim1.5\,{\rm pMpc}$ at $z\sim10$) for
galaxies with M$_{\rm UV}<-19.5$, $-20$, and $-20.5$. Comparing to
galaxies in the fiducial UniverseMachine, we find that $\sigma_{\rm CV}$ is consistent with our measurements, but that the number densities are a factor $\gtrsim5$ lower. We implement simple models in the UniverseMachine that represent different physical mechanisms to enhance the number density of UV-bright
galaxies. All models decrease $\sigma_{\rm CV}$ by placing
galaxies at fixed M$_{\rm UV}$ in lower mass
halos, but to varying degrees. Combined constraints on $\sigma_{\rm CV}$ and the UVLF thus tentatively disfavor models that globally increase the
star formation efficiency (SFE) or the scatter in the M$_{\rm UV}$-$M_{\rm halo}$ relation, while models that decrease the mass-to-light ratio, or assume a power-law scaling of the SFE with $M_{\rm halo}$ agree better with the data. We show that with sufficient additional independent sightlines, robust discrimination between models is possible, paving the way for powerful constraints on the physics of early
galaxy evolution through NIRCam pure parallel imaging.
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All authors Andrea Weibel, Christian Kragh Jespersen, Pascal A. Oesch, Christina C. Williams, Rachel Bezanson, Gabriel Brammer, Aidan P. Cloonan, Pratika Dayal, Anne Hutter, Zhiyuan Ji, Michael V. Maseda, Marko Shuntov, Katherine E. Whitaker
Astrophysics of Galaxies
Mass Assembly and Chemical Complexity in the Milky Way
Pamela Klaassen, David Eden, Alessio Traficante et al. (+13 more)
(Sub-)millimeter spectral lines can be used not only to understand the chemical complexity and enrichment history of an observed portion of our
Galaxy, but with spectrally resolved lines, they reveal the physical conditions, dynamics, and even the ionisation state and
magnetic field strengths of the gas component of our
Galaxy. They are
prime tracers of mass assembly and structure formation across scales.
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All authors Pamela Klaassen, David Eden, Alessio Traficante, Henrik Beuther, Maite Beltrán, Caroline Bot, Elias Brinks, Laura Colzi, Timea Csengeri, Antoine Gusdorf, Doug Johnstone, Jes K. Jørgensen, Jonathan Marshall, Elena Redaelli, Víctor M. Rivilla, Thomas Stanke
Solar and Stellar Astrophysics
Yunfang Cai, Yongyuan Xiang and Kaifan Ji
High spatial resolution observation of
solar prominence is an important observation subject of the New
Vacuum Solar Telescope (NVST). While the current level of observation and image reconstruction technologies for
solar prominences are advanced, a significant challenge remains in achieving high-precision
alignment among high-resolution prominence images observed at different times and different off-bands. Existing
alignment approaches either become ineffective or yield low accuracy, and always require manual intervention during the
alignment. These limitations are largely due to the stronger edge gradient and lower structural contrast of the prominence images compared with the
solar surface ones. In response to this challenge, our study aims to develop an effective and robust
algorithm for high-precision
alignment of the prominence images. We thoroughly consider the unique structural characteristics of prominence images and the specific application conditions of various
alignment algorithms. Consequently, we propose a comprehensive
alignment method that incorporates the optical flow field of the
solar surface, the gradient of the
solar edge, and the cross-correlation within the
solar prominence region. This method is designed to accurately determine the movement displacements among the prominence images. Our results demonstrate that this
alignment method excels in both accuracy and robustness, making it well-suited for handling the diverse postures of
solar prominence images captured by the NVST.
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High Energy Astrophysical Phenomena
Fermi-LAT detections of novae V1723 Sco and V6598 Sgr
P. Fauverge, P. Jean, K. Sokolovsky et al. (+8 more)
Context. Numerous classical novae have been observed to emit {\gamma}-rays (E > 100 MeV) detected by the
Fermi-LAT. The prevailing hypothesis attributes this emission to the interaction of accelerated particles within shocks in the nova ejecta. However, the lack of non-thermal X-ray detection coincident with the {\gamma}-rays remains a challenge to this theory. Methods. We performed similar analyses of the
Fermi-LAT data for both novae to determine the duration, localization, and spectral properties of the {\gamma}-ray emission. These results were compared with optical data from the AAVSO database and X-ray observations from NuSTAR, available for V1723 Sco 2024 only, to infer the nature of the accelerated particles. Finally, we used a physical emission model to extract key parameters related to particle acceleration. Results. V1723 Sco 2024 was found to be a very bright {\gamma}-ray source with an emission duration of 15 days allowing us to constrain the spectral index and the total energy of accelerated
protons. Despite early NuSTAR observations, no non-thermal X-ray emission was detected simultaneously with the {\gamma}-rays. However, unexpected {\gamma}-ray and thermal hard X-ray emission were observed more than 40 days after the nova outburst, suggesting that particle acceleration can occur even several weeks post-eruption. V6598 Sgr 2023, on the other hand, was detected by the
Fermi-LAT at a significance level of 4{\sigma}over just two days, one of the shortest {\gamma}-ray emission durations ever recorded, coinciding with a rapid decline in optical brightness. Finally, the high ratio of {\gamma}-ray to optical luminosities and {\gamma}-ray to X-ray luminosities for both novae, as well as the
curvature of the {\gamma}-ray spectrum of V1723 Sco below 500 MeV, are all more consistent with the hadronic than the leptonic scenario for {\gamma}-ray generation in novae.
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All authors P. Fauverge, P. Jean, K. Sokolovsky, C. C. Cheung, M. Lemoine-Goumard, M.-H. Grondin, L. Chomiuk, A. Dickenson, J. D. Linford, K. Mukai, J. L. Sokoloski
Astrophysics of Galaxies
NIKA2 Cosmological Legacy Survey. First measurement of the confusion noise at the IRAM 30 m telescope
N. Ponthieu, F.-X. Désert, A. Beelen et al. (+54 more)
The NIKA2 Cosmological Legacy Survey (N2CLS) is a large programme using the NIKA2 dual-band camera on the IRAM 30\,m
telescope. Its goal is to improve our understanding of the physics of distant Dusty
Star Forming
Galaxies (DSFGs) by carrying out deep surveys of two fields, GOODS-North and COSMOS. This work is focussed on GOODS-North, which was observed for 78.2 hours, simultaneously at 1.2 and 2\,mm, with a field of view of $\sim$240\,arcmin$^2$. With such a deep integration, we were able to measure, for the first time, the confusion noise limits at the 30\,m
telescope using the best sampled $\sim 62$\,arcmin$^2$ and masking sources with a flux greater than 0.54 or 0.17\,mJy at 1.2 or 2\,mm, respectively. We found a confusion noise of $139.1^{+ 15.9}_{- 19.2}\pm11.9$\,$\mu$Jy/beam at 1.2\,mm and $38.6^{+ 9.6}_{- 13.1} \pm3.7$\,$\mu$Jy/beam at 2\,mm (the first uncertainty is statistical, the second is the
cosmic variance). In this region, this corresponds to half the instrumental noise. To derive these estimates, we devised a novel
estimator, referred to as the cross variance, which also enabled us to estimate the correlated confusion noise between the two bands. Thus, we obtained a result of $49.6^{+ 15.9}_{- 24.8}\pm 6.4$\,$\mu$Jy/beam. These values are consistent with the state of the art Simulated Infrared Dusty Extragalactic Sky (SIDES) model.
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All authors N. Ponthieu, F.-X. Désert, A. Beelen, R. Adam, P. Ade, H. Ajeddig, S. Amarantidis, P. André, H. Aussel, A. Benoît, S. Berta, M. Béthermin, L. J. Bing, A. Bongiovanni, J. Bounmy, O. Bourrion, M. Calvo, A. Catalano, D. Chérouvrier, M. De Petris, S. Doyle, E. F. C. Driessen, G. Ejlali, A. Ferragamo, A. Gomez, J. Goupy, C. Hanser, S. Katsioli, F. Kéruzoré, C. Kramer, B. Ladjelate, G. Lagache, S. Leclercq, J.-F. Lestrade, J. F. Macías-Pérez, S. C. Madden, A. Maury, F. Mayet, A. Monfardini, A. Moyer-Anin, M. Muñoz-Echeverría, I. Myserlis, R. Neri, A. Paliwal, L. Perotto, G. Pisano, V. Revéret, A. J. Rigby, A. Ritacco, H. Roussel, F. Ruppin, M. Sánchez-Portal, S. Savorgnano, K. Schuster, A. Sievers, C. Tucker, R. Zylka
High Energy Astrophysical Phenomena · Cross-listed from gr-qc
Inspiral-Transition-Plunge Gravitational Waveforms Beyond Kerr: A Kerr-Newman Case Study
Daiki Watarai, Kent Yagi and Shammi Tahura
Binary black hole mergers with asymmetric component masses are key targets for both third-generation ground-based and future space-based gravitational-wave (GW) detectors, offering unique access to the strong-field dynamics of
gravity. The
evolution is commonly divided into three stages: the adiabatic inspiral, the transition, and the plunge. To date, constructions of inspiral-transition-plunge waveforms have largely focused on Schwarzschild or Kerr background spacetimes. In this paper, we extend these efforts to spacetimes beyond Kerr by constructing such waveforms in a Kerr-Newman background. For simplicity, we allow the primary black hole to carry
spin and charge while keeping the secondary object neutral and non-spinning. We work in the small charge-to-mass ratio regime and adopt the Dudley-Finley approximation, in which the gravitational and electromagnetic perturbations decouple. In particular, the gravitational sector satisfies a Teukolsky-like equation, enabling only minimal modifications relative to the Kerr case when constructing the waveform. Having the inspiral-transtion-plunge waveforms in hand, we studied observational prospects for constraining the charge of the central black hole. We find that, for intermediate-mass-ratio mergers observed with the Einstein
Telescope, explicitly modeling the post-inspiral dynamics significantly tightens charge-to-mass ratio constraints. In particular, the bounds on the charge-to-mass ratio can reach $O(10^{-3})$ in the region of primary masses and
spins where the post-inspiral signal dominates, yielding charge bounds that can be orders of magnitude tighter than those obtained from the inspiral alone or from the current bound with GW150914. These results lay the groundwork for inspiral-transition-plunge waveform modeling in beyond-Kerr spacetimes and for probing non-Kerr signatures in future GW observations.
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Astrophysics of Galaxies
Can dwarf spheroidal galaxies host a central black hole ?
K. Aditya and A. Mangalam
We construct mass models of Milky Way
dwarf spheroidal
galaxies to place constraints on the central black hole (BH) masses they can host. We model the
galaxies as a three-component system consisting of the
stars, dark matter
halo, and a central black hole, using the Osipkov–Merritt–Cuddeford class of anisotropic distribution function. The posterior distribution of black hole mass remains flat toward the low-mass end, indicating that the kinematic data places an upper limit on the black hole mass. Our analysis yields a 95% credible upper limit of $\log(M_{\bullet}/M_{\odot}) < 6$. We combine our results with black hole mass measurements and upper limits from the literature to construct a unified $M_{\bullet}$–$\sigma_{}$ relation spanning $\sigma_{} \sim 10$–$300,\mathrm{km,s^{-1}}$, described by $\log(M_{\bullet}) = 8.32 + 4.08,\log\left(\sigma_{}/200,\mathrm{km,s^{-1}}\right)$, with an intrinsic scatter of $\sigma_{\rm int} = 0.55$. We compare the inferred limits to models of black hole growth via momentum-driven
accretion and
stellar capture, which predict black hole masses in the range $10^{3}$–$10^{4},M_{\odot}$ for the range $\sigma_{} \sim 6$–$12,\mathrm{km,s^{-1}}$, in close agreement with the $M_{\bullet}$–$\sigma_{*}$ relation within the 95% credible upper limits on the black hole masses derived in this work.
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Astrophysics of Galaxies
The role of supernova remnants for the emergence of pre-biotic chemistry in molecular clouds
Giuliana Cosentino, Izaskun Jiménez-Serra, Laura Colzi et al. (+11 more)
There is growing evidence that the Sun might have formed within a nebula impacted by at least one SNR. In this scenario, ejecta and shocks from SNRs may have provided the elements on which life as we know it is based. Investigating the chemical complexity of molecular clouds impacted by SNRs is therefore essential to unveil the
star formation process and how life appeared on Earth. In this paper, we exploit this scientific questions and describe which technical specifications will drive in future generation
telescopes.
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All authors Giuliana Cosentino, Izaskun Jiménez-Serra, Laura Colzi, Víctor Rivilla, Francisco Montenegro-Montes, Miguel Sanz-Novo, Marta Rey-Montejo, Andrés Megías, David San Andrés, Sergio Martín, Shaoshan Zeng, Amelie Godard, Miguel Requena-Torres, Juris Kalvāns
Earth and Planetary Astrophysics
Vertically resolved minimal-set k-distribution for thermal infrared absorption: an application to the atmosphere of Venus
Boris Fomin and Mikhail Razumovskiy
The FKDM $k$-distribution technique is applied to parameterize absorption of thermal radiation in the lower and middle atmosphere of Venus, targeting modeling scenarios where the cost of full radiative transfer calculations necessitates efficient parameterizations (e.g.
climate modeling). Line-by-line reference modeling based on a Monte Carlo method for radiative transfer is built into the $k$-distribution terms construction process, explicitly controlling accuracy. From 16 bands across $10$–$6000~\mathrm{cm^{-1}}$, the method produces 32 $k$-terms, band-averaged Planck function values and per-band spectral points for computing Venus cloud optical properties. The FKDM $k$-distribution technique does not require the inter-level correlation assumption common for the correlated $k$-distribution method. We supply height-dependent $k(z)$ functions tabulated on the same vertical grid as the input temperature-pressure profile, designed for direct use in radiative transfer solvers and avoiding additional remapping of the pre-tabulated $k$-data. Our implementation of the technique yielded acceptable accuracy below 90~km ($<1.2~\mathrm{K\,day^{-1}}$ for cooling rates; $<2\%$ for fluxes), while requiring substantially fewer $k$-terms than recent implementations of the correlated-$k$ method. A Fortran driver that generates $k(z)$ functions for an arbitrary Venus atmospheric profile is provided in a public repository.
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Astrophysics of Galaxies · Cross-listed from hep-ex
Any Light Particle Searches with ALPS II: first science results
Daniel C. Brotherton, Zachary R. Bush, Sandy Croatto et al. (+37 more)
The light-shining-through-a-wall experiment ALPS II at DESY in Hamburg searched for
axions and similar lightweight particles in its first science campaign from February to May 2024. No evidence for the existence of such particles was found. For pseudoscalar
bosons like the
axion, with masses below about 0.1 meV, we achieved a limit for the di-
photon coupling strength of 1.5e-9 1/GeV at a 95% confidence level. This is more than a factor of 20 improvement compared to all previous similar experiments. We also provide limits on
photon interactions for scalar, vector and tensor
bosons. An achievement of this first science campaign is the demonstration of stable operation and robust calibration of the complex experiment. Currently, the optical system of ALPS II is being upgraded aiming for another two orders of magnitude sensitivity increase.
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All authors Daniel C. Brotherton, Zachary R. Bush, Sandy Croatto, Mauricio Diaz-Ortiz Jr., Jacob Egge, Aldo Ejlli, Henry Frädrich, Joe Gleason, Hartmut Grote, Ayman Hallal, Michael T. Hartman, Harold Hollis, Katharina-Sophie Isleif, Alasdair L. James, Friederike Januschek, Kanioar Karan, Sven Karstensen, Todd Kozlowski, Axel Lindner, Giuseppe Messineo, Manuel Meyer, Guido Müller, Ryan Netrval, Isabella Oceano, Gulden Othman, Jan H. Põld, David Reuther, Andreas Ringwald, Elmeri Rivasto, José Alejandro Rubiera Gimeno, Jörn Schaffran, Uwe Schneekloth, Christina Schwemmbauer, Richard C.G. Smith, Aaron D. Spector, David B. Tanner, Dieter Trines, Li-Wei Wei, Benno Willke, Rachel Wolf
Astrophysics of Galaxies
Yang Su, Xin Liu, Shiyu Zhang et al. (+7 more)
The origin of the multiphase gas within the
Fermi/eROSITA bubbles is crucial for understanding
Galactic Center (GC) feedback. We use HI4PI data to investigate the kinematics and physical properties of high-velocity clouds (HVCs) toward the GC. Our results reveal that the HVCs exhibit a distinct asymmetric distribution, closely associated with the bar-driven tilted
dust lanes and the distorted overshooting streams. We propose that powerful
nuclear outflows interact with these gas-rich, off-plane structures, striping and entraining cold gas from the outer
Galactic regions (R_GC~0.5–1.7 kpc) rather than solely from the region of the central molecular zone (CMZ; R_GC<0.3 kpc). In this scenario, as the
Galactic bar drives gas inflows along the
dust lanes,
nuclear outflows simultaneously break through the CMZ, sweeping up and ablating cold gas from the boundary layer of these pre-existing structures. This process naturally accounts for the observed high
turbulence, complex spectral signatures, and anomalous spatial-kinematic gas patterns, as well as multiwavelength asymmetries of the bubbles. The HVCs are accelerated to about 230–340 km/s over a dynamical time of ~3–6 Myr. When the multiphase, inhomogeneous composition of the gas is included, the estimated gas
outflow rate reaches ~1 Msun/yr. This value is comparable to the bar-driven inflow rate, indicating a tightly coupled gas cycle in the inner
Galaxy. Our research highlights the critical role of bar-driven gas dynamics and
nuclear feedback in the secular
evolution of the Milky Way, offering a valuable paradigm for investigating gas cycles in external
galaxies.
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All authors Yang Su, Xin Liu, Shiyu Zhang, Ji Yang, Yan Sun, Shaobo Zhang, Fujun Du, Xin Zhou, Qing-Zeng Yan, Xuepeng Chen
Astrophysics of Galaxies
Primordial Black Holes as Seeds for Extremely Overmassive AGN Observed by JWST
Saiyang Zhang, Boyuan Liu, Volker Bromm et al. (+1 more)
The James Webb Space
Telescope (JWST) has recently identified Abell 2744-QSO1 as a compact, metal-poor, black hole (BH) dominated
galaxy at $z\simeq 7$. This system exhibits an extreme black-hole-to-
stellar mass ratio and unusually low
metallicity, posing significant challenges to BH seeding models. Motivated by these discoveries, we perform high-resolution cosmological simulations with a massive
primordial black hole (PBH; $M_{\rm BH}=5\times10^7\,M_\odot$) seed, incorporating for the first time a fully coupled treatment of PBH
accretion, BH feedback, and Population~III/II
star formation and
stellar feedback. Although PBHs accelerate structure formation through the seed effect, the associated strong thermal feedback from the
accretion delays the onset of
star formation to $z\lesssim 10$, producing short, bursty episodes throughout the subsequent
evolution. PBH-driven
outflows expel enriched gas from the
nucleus, while sustained inflows from the intergalactic medium continuously replenish pristine material. This feedback-regulated cycle naturally yields low
accretion rates ($\dot{m}_{\rm BH}/\dot{m}_{\rm edd} \sim 1-10\%$), subsolar
metallicities ($Z/Z_\odot\lesssim10^{-2}$) and extreme $M_{\rm BH}/M_\star$ ratios during both the initial
star-forming phase and the subsequent quenching phases, in excellent agreement with JWST observations. Our results demonstrate that massive PBHs offer a viable pathway for forming the most extreme high-
redshift systems, providing a physically motivated explanation for the extraordinary properties of Abell 2744-QSO1, as a sub-class of the broader population of JWST-discovered "little red dots".
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All authors Saiyang Zhang, Boyuan Liu, Volker Bromm, Florian Kühnel