Instrumentation and Methods for Astrophysics
Demonstration of a multimode-to-multimode photonic lantern for astronomy
Marina Centenera-Merino, Andrew Ross-Adams, Christopher Betters et al. (+14 more)
Photonic lanterns have been widely used in astronomy as low-loss multiplexing devices, typically coupling light from a multimode input into several single-mode outputs. In this work, we present the first multimode-to-multimode photonic lantern specifically designed to combine light from several multimode fibers into a single multimode waveguide. We fabricated and characterized the devices at multiple wavelengths to evaluate the performance of the adiabatic multimode transition. The measured efficiencies exceed $90\ \%$, demonstrating low-loss multimode propagation and efficient modal transfer through the lantern structure. This architecture enables efficient multimode beam combination and represents a significant step toward scalable modular
telescope concepts without requiring diffraction-limited injection.
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All authors Marina Centenera-Merino, Andrew Ross-Adams, Christopher Betters, Pedro J. Amado, Jesus Aceituno, Kalaga Madhav, Stefan Cikota, F. Javier Flores, Julius Göhring, Abani S. Nayak, Jose Luis Ortiz, David Peréz-Medialdea, Francisco J. Pozuelos, Martin M. Roth, Mabel Ruíz-López, Miguel Andrés Sánchez-Carrasco, Sergio Leon-Saval
Astrophysics of Galaxies
The efficient star-forming regions of stripped-envelope supernovae
M. Solar, M. J. Michałowski, J. Nadolny et al. (+13 more)
Massive
stars ($> 8~\rm{M}_{\odot}$) play a key role in shaping the interstellar medium of
galaxies through
stellar feedback. However, how these
stars form and evolve before exploding as core-collapse
supernovae (SNe) remains elusive. We compute for the first time the
star-formation efficiencies (SFEs) at the locations of hydrogen-rich (H-rich) SNe and stripped-envelope SNe (SESNe) to constrain their progenitor properties. We used VLT/MUSE and ALMA observations of H$\alpha$/H$\beta$ and CO(2-1) emission lines to trace the components of the warm ionised gas and cold molecular gas, respectively. Both observations resolve individual H II regions and
giant molecular clouds at spatial resolutions on cloud-scales ($\sim$100 pc). This combined data allows us to compute the SFE from the
star formation rate (SFR) and the molecular gas mass (M$_{\rm{mol}}$) as SFE = SFR/M$_{\rm{mol}}$. We find that SESNe explode in environments that are currently forming
stars eight times more efficiently than those of H-rich SNe (higher SFR for SESNe with similar M$_{\rm{mol}}$). On one hand, this is consistent with the scenario in which the majority of SESNe are produced from very massive
stars ($> 20~\rm{M}_{\odot}$) if the initial mass function is top-heavy. On the other hand, most of SESN progenitor channels are formed from interacting binaries ($< 20~\rm{M}_{\odot}$) if an increased binary system formation rate is connected with turbulences and, in turn, with the boost to SFE. Then, an increased binary fraction could explain the enhanced H$\alpha$ luminosities. In summary, SESNe preferentially occur in regions of intense, efficient
star formation rather than simply higher gas content.
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All authors M. Solar, M. J. Michałowski, J. Nadolny, L. Galbany, J. P. Anderson, J. Sollerman, T. Pessi, E. Zapartas, B. Šlaus, J. Alexander, O. Ryzhov, J. Hjorth, C. Jiménez-Palau, P. Nowaczyk, D. Somawanshi, A. Leśniewska
Instrumentation and Methods for Astrophysics
VERITAS 2.3.1: Optimisation and Characterisation of the Enhanced Readout ASIC for the NewAthena Wide Field Imager
Ajay Kumar Dakshinamurthy, Sven Herrmann, Peter Orel et al. (+7 more)
VERITAS 2.3.1 is the next iteration of the VErsatile Readout based on Integrated Trapezoidal Analogue Shapers (VERITAS) integrated
circuit (IC) architecture for high-speed, low-noise readout of DEPleted Field Effect Transistor (DEPFET) detectors in the Wide Field Imager (WFI) on ESA's NewAthena X-ray satellite. Building on VERITAS 2.3, which demonstrated a short processing time of 2.5 us per readout and a system noise target of about 3 e- ENC RMS, the VERITAS 2.3.1 revision has been improved with additional features and targeted optimisations of existing analogue and digital blocks, alongside refined layout routing to reduce parasitic effects, to improve transient behavior, cross talk, manufacturability, and reliability while preserving the proven VERITAS architecture. The functionality and performance of VERITAS 2.3.1 was characterised in two steps. First by using a dedicated application specific integrated
circuit (ASIC) only test setup. Second, a full scale module test setup is used, with integrated DEPFET sensors and readout electronics, under
vacuum and at mission like temperatures. This paper presents the design updates and implementation details of the VERITAS 2.3.1, compares its measured performance to that of VERITAS 2.3, and discusses the impact of the added features, block-level optimisations, and routing improvements on overall system performance.
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All authors Ajay Kumar Dakshinamurthy, Sven Herrmann, Peter Orel, Anna-Katharina Schweingruber, Astrid Mayr, Johannes Muller-Seidlitz, Jonas Reiffers, Sebastian Albrecht, Steven W. Allen, Glenn Morris
Instrumentation and Methods for Astrophysics
Estimation of systematic error from bulk deformation of end test mass induced by photon calibrator for LIGO post-O5 gravitational wave projects
Daiki Tanabe, Aloysius Niko, Kun-Yao Chang et al. (+4 more)
We studied the bulk deformation of the end test masses (ETMs) of gravitational wave (GW) detectors caused by calibration devices named
Photon Calibrator (Pcal). This bulk deformation is one of the source of calibration error since it induces non-linear displacement from the ideal pendulum motion of the ETM. Particularly, it is the dominant error source above 1500 Hz which is crucial to the studies of
neutron star mergers. The displacement also depends on beam offsets of the main interferometer (IFO) beam and Pcal beams. We conceptually described frequency dependent effect of bulk deformation and evaluated it in several cases of the beam offset with finite-element analysis (FEA) software, for ETM models of Advanced LIGO (aLIGO), KAGRA, Advanced Virgo (AdVirgo), and LIGO A#.
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All authors Daiki Tanabe, Aloysius Niko, Kun-Yao Chang, Yuki Inoue, Dripta Bhattacharjee, Richard Savage, Henry Tsz-King Wong
High Energy Astrophysical Phenomena
Simulation of advective accretion flows around black holes under various outer boundary conditions
Rajiv Kumar and Seong-Jae Lee
We simulated various
accretion disc structures with viscous hydrodynamic (HD) flow around a black hole (BH). We found that the structure of the
accretion disc is significantly influenced by changes in the physical parameters of the initial inflowing gases. These physical parameters can be called outer boundary conditions (OBCs) at the outer-
accretion boundary and represented on an OBC plane, which is primarily divided into hot-mode and cold-mode inflowing gases. We found smooth and shocked flows in the simulation, which follow the semi-analytical solutions with their OBCs. Interestingly, we observed that certain types of OBCs can produce shocks with jet-like features in the
accretion flow. However, other OBCs can produce smooth or shock-free
accretion flow, which may or may not have
outflows. The smooth flows can display both the lowest and highest angular momentum distributions among the advective flows, depending on the OBCs. Additionally, the nature of the
accretion flows can be either steady or quasi-steady, also influenced by the OBCs. We also observed that solutions corresponding to hot-mode gases have a greater tendency to generate
outflows compared to those with the cold-mode. Therefore, this qualitative study of OBCs is crucial for understanding
accretion physics, which can aid in modeling
accretion discs, similar to the quantitative studies (which involve only changing mass
accretion rates) of the inflowing gases. Thus, we assert that an
accretion model should be based on both the qualitative and quantitative aspects of the initial inflowing gases.
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Earth and Planetary Astrophysics
A metallicity sweet spot for disc fragmentation and planet formation
Ethan J. Carter, Dimitris Stamatellos, George Blaylock-Squibbs et al. (+2 more)
Fragmentation of gravitationally unstable discs offers an alternate formation mechanism for gas
giant planets and brown
dwarfs on wide orbits.
Metallicity plays a key role in disc
evolution from the onset of gravitational instability to the formation of
planets. We aim to determine the effect of
metallicity on disc fragmentation and on the properties of disc-instability
planets. We model gravitationally unstable discs with varying
metallicity ($0.01-10 \,\rm Z_{\odot}$) using the Smoothed Particle Hydrodynamics code PHANTOM. Our simulations reveal a "sweet spot" for fragmentation at $0.3 \,\rm Z_{\odot}$, where cooling is most efficient, with fragmentation also happening less vigorously at higher and lower
metallicities. However, further away from the sweet spot, fragmentation becomes more difficult and is eventually suppressed at extreme low and high
metallicities ($0.01 \,\rm Z_{\odot}$ and $10 \,\rm Z_{\odot}$, respectively), where the disc cools inefficiently. Discs with
metallicities close to the sweet spot form more
planets per disc, faster, and with lower initial masses than fragmenting discs with higher or lower
metallicities. Our results may explain the slight overabundance of wide-orbit
giant planets observed around metal-poor
stars; these
planets may have formed via disc fragmentation.
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All authors Ethan J. Carter, Dimitris Stamatellos, George Blaylock-Squibbs, Alison Young, Ken Rice
High Energy Astrophysical Phenomena
Automatically distinguishing Rubin transients from AGN using variability metrics
Dylan Magill, Matt Nicholl, Philip Wiseman et al. (+7 more)
Stochastic variability of active
galactic nuclei (AGN) can produce contaminants in the search for explosive extragalactic transients (such as
supernovae and
tidal disruption events). In the new era of the Rubin Observatory's Legacy Survey of Space and Time (LSST), previously uncatalogued AGN, especially those with luminosity near the survey detection limits, are expected to produce a flood of detections that have the potential to contaminate surveys targeting other transients, leading to inefficient use of spectroscopic follow-up time. For surveys aiming to statistically characterise transient demographics, it is advantageous to use easily modelled and reproducible selection criteria to distinguish AGN from other transients, rather than machine learning. We test enacting cuts based on simple data-driven photometric variability parameters to distinguish non-AGN extragalactic transients from standard AGN variability on both Zwicky Transient Facility photometry and simulated LSST photometry from the MALLORN data set. We also investigate the impact of light curve history availability,
redshift range and filter selection on selection efficiency. We find that a two-dimensional cut incorporating the ratio of detection flux and pre-detection standard deviation and the ratio of detection flux to pre-detection mean flux is the most effective cut. This approach is easily scalable as these values are included in the LSST alert packets. We provide estimates of the completeness and purity of the sample produced by enacting this cut, and gauge the AGN contamination avoided. The parameters utilised in this approach could also be implemented as features for identifying AGN in a photometric classifier.
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All authors Dylan Magill, Matt Nicholl, Philip Wiseman, Charlotte R. Angus, Paige Ramsden, Christopher Frohmaier, Sjoert van Velzen, Vysakh Anilkumar, Jaimee Greenwood, Joshua G. Weston
Solar and Stellar Astrophysics · Cross-listed from physics.hist-ph
Could John Ellard Gore have pre-empted the Hertzsprung-Russell diagram?
Jeremy Shears
John Ellard Gore (1845-1910) was an Irish amateur astronomer, prolific science writer and civil engineer. He was an inaugural member of the British Astronomical Association when it was founded in 1890 and was invited to become the first Director of its Variable
Star Section. Through careful
reasoning, Gore reached remarkably modern conclusions about the nature of
stars, including their sizes, distances and luminosities. This paper explores whether he might have been able to produce an early form of what is now known as the Hertzsprung-Russell (H-R) diagram.
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Instrumentation and Methods for Astrophysics
Millimeter and sub-millimeter characterization of polymers used for infrared filters in high-sensitivity cryogenic microwave telescopes
Miranda Eiben, Rustam Balafendiev, Thomas Gascard et al. (+1 more)
Vacuum windows and infrared filters are important transmissive optical components in millimeter receivers, as they hold out the atmosphere and reduce radiative loading on cold stages, thereby improving cryogenic performance. However, the complex optical properties of the materials commonly used for windows and filters are poorly characterized, particularly in-band and in the sub-millimeter regime. The absorption and scattering properties of these materials are becoming increasingly important for designing high-sensitivity millimeter instruments, as their loosely constrained properties are one of the greatest sources of uncertainty remaining in noise modeling. We report the absorption in the millimeter and sub-millimeter regime of nylon 6, nylon 6/6, PTFE and polyethylene (both bulk HDPE and foam HDPE used in
radio transparent filter stacks). Additionally, we report the relative power scattered out of the main beam by these materials from 90 to 330 GHz, measured in free space by a
robot-enabled scanning vector network analyzer.
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All authors Miranda Eiben, Rustam Balafendiev, Thomas Gascard, Jon E. Gudmundsson
Earth and Planetary Astrophysics · Cross-listed from physics.hist-ph
The Birth of Radar Meteor Astronomy at Jodrell Bank: The Collaboration between Bernard Lovell and Manning Prentice
Jeremy Shears
The discovery of radar echoes from meteor trains at Jodrell Bank in December 1945 heralded the beginning of a new era in meteor astronomy. This paper examines the early collaboration between Bernard Lovell, whose expertise in radar and physics transformed wartime technology into a new astronomical technique, and J. P. Manning Prentice, Director of the British Astronomical Association Meteor Section, whose knowledge of visual meteor observation proved essential to interpreting the discoveries. Drawing on previously unpublished correspondence from the Lovell Archive at the University of Manchester, the paper traces the development of their partnership, including the pioneering 1946 Perseid and Giacobinid observations, the contribution of BAA observers, and the establishment of radar meteor research at Jodrell Bank. It reveals how complementary professional and amateur expertise combined to create a new field of astronomy and a lasting scientific friendship.
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Astrophysics of Galaxies
Size-Mass Relation Shows Its Colours: Contrasting Physical Imprints of Galaxy Evolution in Rest-Frame UV and Optical
Angelo George, Marcin Sawicki and Ivana Damjanov
The
galaxy size-mass relation (SMR) is a key scaling relation used to constrain the physical processes that build
galaxy structure, yet it is almost always measured in a single rest-frame optical band, where the light traces the bulk of the old
stellar mass. Tracing younger populations with flux-weighted ages of ~100-500 Myr and low-
metallicity stars, the rest-frame near-ultraviolet opens a new
stellar window on this scaling relation. Because each process redistributes the light of young and old
stars differently, the same mechanism shifts the slope and zero point of the SMR by different amounts in the two wavelength regimes. Here we review and synthesize the effects of main physical processes on the form of the SMR for
star-forming and quiescent
galaxies in the rest-UV and optical. For each process, we start from its underlying physics, the
galaxy stellar masses it affects, and the light it adds/removes/rearranges, anchoring the predictions to observations and simulations. We validate the predicted imprints with forward Monte Carlo modelling. The two-wavelength view breaks several degeneracies that single-band analyses cannot, most notably between minor mergers, dry major mergers, and adiabatic expansion. These results motivate joint rest-UV and optical SMR measurements with current and upcoming wide-field imaging surveys.
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Instrumentation and Methods for Astrophysics · Cross-listed from hep-ex
Technical Proposal for the Atom Interferometer CERN Experiment (AICE) Facility
Gianluigi Arduini, Nadja Augst, Mark G. Bason et al. (+79 more)
We present the technical proposal for the Atom Interferometer CERN Experiment (AICE), a $\mathcal{O}(100)$ m vertical atom interferometer to be installed against the wall of the PX46 access shaft to the LHC. AICE is conceived as a versatile and flexible long-baseline atom-interferometry facility whose primary scientific goal is probing for bosonic ultralight dark matter (ULDM) in a mass range inaccessible to other experiments, with a secondary goal of pioneering the exploration of gravitational waves (GWs) with frequencies in the range ${\sim}$0.03-3 Hz as a pathfinder for future longer-baseline detectors. The initial configuration employs ultracold $^{87}$Sr atoms in a single-
photon 698-nm interferometer with three shaft-based atom sources in a multi-source gradiometer geometry, supported by one surface reference source for
laser stabilisation and diagnostics, to target scalar ULDM. Operation with $^{88}$Sr will give sensitivity to
axion-like particles (ALPs), vector ULDM with $B-L$ couplings and violation of the principle of equivalence, while a $^{171}$Yb upgrade will improve the sensitivity to $B-L$ couplings and equivalence violations. Probing the Einstein equivalence principle (EP) and measuring $\alpha$ will proceed in parallel with the ULDM searches. A conceptual feasibility study and a detailed technical implementation study have established that PX46 is a uniquely mature and implementation-ready site, with no technical showstoppers. Completing site preparation works during LS3 would enable the subsequent installation and operation of AICE without impacting HL-LHC operations. The detector design builds on the VLBAI and MAGIS experiments and the AION-10 Technical Design Report, scaling the strontium gradiometer architecture to the $\sim$100 m baseline. AICE is endorsed by the TVLBAI Proto-Collaboration, comprising 57 institutions in 22 countries.
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All authors Gianluigi Arduini, Nadja Augst, Mark G. Bason, Charles Baynham, Andrea Bertoldi, Gianfranco Bertone, Diego Blas, Daniela Bortoletto, Sougato Bose, Roberto Ales Bozzi, Oliver Buchmueller, Tamara Alice Bud, Clare Burrage, Sergio Calatroni, John Carlton, Vassilis Charmandaris, Maria Luisa Chiofalo, Pierre Cladé, Jonathon Coleman, Fabio Corsanego, Albert De Roeck, Arnaud Devienne, Fabio Di Pumpo, John Ellis, Pierre Fayet, Chris Foot, Elina Fuchs, Naceur Gaaloul, Susan Gardner, Enno Giese, Eduardo Granados, Saïda Guellati-Khelifa, Michael Guinchard, Timo Hakulinen, Tiffany Harte, Richard Hobson, Michael Holynski, Angelo Infantino, Alex Kehagias, Eva Kilian-Rademacher, Wolfgang Korsch, Damien Lafarge, Samuel Lellouch, Lucas Lombriser, Elias Lopez Asamar, J. Luis Lopez-Gonzalez, Michele Maggiore, Charline Marcel, Anna Marchant, Christopher McCabe, Gaetano Mileti, Peter Millington, Jeremiah Mitchell, Noam Mouelle, Angel Navascues Cornago, François Pillon, Rosa Poggiani, Johann Rafelski, Ernst M. Rasel, Maike Reckermann, Albert Roura, Rui Samoes, Federico Sanchez Nieto, Jack Sander, Carlo Scarcia, Jesse Schelfhout, Wolfgang Schleich, Dennis Schlippert, Ulrich Schneider, Steven Schramm, Florian Schreck, Olga Sergijenko, Marcelle Soares-Santos, Guglielmo M. Tino, Jonathan N. Tinsley, Tristan Valenzuela, Daniel Valuch, Maurits van der Grinten, Klaasjan van Druten, Ville Vaskonen, Wolf von Klitzing, Michael Werner
High Energy Astrophysical Phenomena
Multi-zone Modeling of Blazar Jets: Constraints from GeV-Optical Correlation and Short-Timescale Variability
Arit Bala, Kaustav Mitra and Ritaban Chatterjee
We have developed a multi-zone model of blazar jet emission, in which the emission region contains many
cells with individual
magnetic fields and electron energy distributions. Nonthermal emission from
radio to $\gamma$-rays is generated by electrons accelerated by shocks passing through the region via synchrotron and inverse-Compton (IC) processes. The optical and GeV variability at days-to-months time-scale simulated from our model are strongly correlated with no significant time lag, as observed in most blazars and indicated by the standard shock-in-jet model. However, the mechanism of the shorter time-scale variability has been less explored, although such fluctuations at X-rays, $\gamma$-rays and optical bands have been observed regularly in recent years. In our model, the hr time-scale variability of the synchrotron radiation is due to the spatial fluctuation of the
magnetic field in the emission region. We found that to reproduce the short-timescale variability of the observed synchrotron emission in blazars, the required fluctuations of the
magnetic field are in the range $1-2\%$ to $25-30\%$. Similar variability of the IC emission, which does not depend on the
magnetic field, may be reproduced in our model by implementing equipartition of energy between the
magnetic field and particles. We found that orphan
flares in the optical or GeV band, or optical-GeV correlation with a significant time delay, as observed occasionally, may be reproduced in certain special conditions related to the orientation of the
magnetic field in the
cells.
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Solar and Stellar Astrophysics
A generalized quadratic balance relation for nonradial nonadiabatic pulsations
Jan Zalewski
We derive a generalized quadratic balance relation for linear nonadiabatic, nonradial
stellar pulsations, starting from a sesquilinear amplitude analogue of the pressure-volume-rate work. The derivation requires neither weak nonadiabaticity nor averaging over a pulsation cycle. The relation is expressed in terms of work, generalized norm and boundary contributions and is subsequently recast into kinetic-energy-power form $\mathcal{P}+\Delta B=2\Re(\sigma)E_{\rm kin}$. The volume power is decomposed into a thermodynamic exchange term and response terms associated with compression, horizontal-area deformation and gravitational stratification effects. The equivalent forms of the relation provide diagnostics for checking the computed eigenfrequencies and estimating mode excitation rates. The properties of the balance relation for various types of modes in an envelope of a model AGB
star are examined. We analyze the terms entering the power $\mathcal{P}$ for radial and nonradial p-modes, strange modes as well as examples of low frequency outer-envelope
gravity modes and thermal modes. The results show that the magnitude of mode driving is not determined solely by the thermodynamic work term.
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Astrophysics of Galaxies
The Total and Polarized Radio Emission from the Innermost Jets of a High-Redshift Quasar and a Candidate at Parsec-Scale Resolution
Bence Husvéth, Krisztina É. Gabányi, Tao An et al. (+4 more)
High-frequency very long baseline interferometry (VLBI) polarimetry probes synchrotron-emitting
plasma closer to the central engines of
radio-loud active
galactic nuclei (AGNs), but observations above 43 GHz are technically demanding. We present 22-GHz European VLBI Network observations of the $z=4.31$
quasar J1510+5702 and J1606+3124, whose published spectroscopic
redshift, $z=4.56$, is uncertain; a photometric estimate gives $z_{\rm phot}=0.9\pm0.1$. For the published $z>4$
redshifts, 22 GHz corresponds to rest-frame frequencies above 118 GHz. Polarized emission is detected in J1510+5702, and a low-level polarized signal is recovered from the brightest feature of J1606+3124. Adopting $z=4.56$, that feature has a brightness temperature of $T_{\mathrm{b,VLBI}}=(7.4\pm0.8)\cdot10^{10}$ K, allowing a mildly Doppler-boosted interpretation, while the young compact-source scenario also remains viable. The core of J1510+5702 has $T_{\mathrm{b,VLBI}}=(1.08\pm0.15) \cdot10^{12}$ K, implying a Doppler factor of ${\sim}22$ under the equipartition assumption. This component has a ${\sim}3.5$ % fractional polarization. These observations show that cm-wavelength VLBI can access rest-frame millimeter-band polarization in bright $z>4$ jets.
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All authors Bence Husvéth, Krisztina É. Gabányi, Tao An, Sándor Frey, Jun Yang, Iván Agudo, Yingkang Zhang
Cosmology and Nongalactic Astrophysics
Broadband Chiral Primordial Gravitational Waves from Constant-roll Inflation in Parity-violating Symmetric Teleparallel Gravity
Xu Zhang, Chang Liu and Chengjie Fu
We investigate
primordial gravitational waves (GWs) generated during constant-roll inflation in a parity-violating extension of symmetric teleparallel
gravity. The parity-violating interactions leave the background
evolution and linear scalar perturbations unchanged, while inducing velocity birefringence in the tensor sector. Consequently, one of the two circular polarization states undergoes tachyonic amplification, producing a strongly blue and nearly fully
chiral tensor spectrum from the
cosmic microwave background (CMB) to interferometer scales. We identify viable constant-roll parameter regions consistent with current CMB constraints and determine the largest coupling strength compatible with both CMB B-mode measurements and the LIGO-Virgo-KAGRA (LVK) O1–O4a bound on the
stochastic GW background. The predicted CMB B-mode spectra may be detectable by LiteBIRD, while the enhanced high-frequency signal could be accessible to the LISA–Taiji network and LVK O5 run. The model also predicts nonvanishing TB and EB correlations. These results highlight the potential of combining CMB and multi-band GW observations to test parity-violating
gravity during inflation.
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Earth and Planetary Astrophysics
Looking for TRAPPIST-1 external planets' emission in JWST archival data
Louis-Julien Cartigny, Alice Maurel, Elsa Ducrot et al. (+1 more)
The TRAPPIST-1 system has been thoroughly observed with JWST. Unfortunately,
stellar contamination issues strongly limit the interpretation of transit observations. As for emission observations, only the two closest
planets have been observed through five dedicated JWST programs. We gathered all these emission observations and tried to detect the combined emission of the external
planets in previous JWST MIRI observations of TRAPPIST-1; this paper presents our approach and our results. We could not achieve sufficient precision to detect the thermal emission of the outer
planets and to discriminate between an all-bare rocks and an all-atmospheres scenario. However, we show that a~60 hours continuous observations at a specific phase range, when the gradient of thermal flux from the outer
planets is maximum, could allow us to achieve this goal.
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All authors Louis-Julien Cartigny, Alice Maurel, Elsa Ducrot, Taylor J. Bell
Astrophysics of Galaxies
Hector Galaxy Survey: Falling in Between - Infalling Galaxies in the Midst of the Abell 3667 Merger
Oğuzhan Çak{\i}r, Matt Owers, Gabriella Quattropani et al. (+38 more)
Whether cluster mergers enhance ram pressure stripping (RPS) and accelerate member
galaxy evolution remains an open question. Here, we investigate
galaxy populations in the nearby merging cluster Abell 3667 ($z\simeq0.0553$) using spatially resolved data from the Hector
Galaxy Survey. We define an RPS sample combining Hector-selected
galaxies with ionised gas disturbances (e.g., asymmetric tails or truncated disks) and supplementary, optically identified jellyfish
galaxies lacking Hector data. Most of the RPS sample ($\sim 71^{+10}_{-7}\%$; 20/28) lies within $R_{200}$, where the merger impact is greater. Most asymmetric
galaxies ($\sim 73^{+14}_{-8}\%$; 11/15), especially those with extreme RPS signatures, are concentrated in the inner cluster ($R \lesssim 0.6\, R_{200}$), along the merger axis between two shock-tracing
radio relics. These central asymmetric
galaxies show two spatial and kinematic groups: one at the North-West (NW) subcluster, downstream of its
radio relic in a region of high-velocity intracluster medium (ICM) bulk motion, with blueshifted line-of-sight velocities; and a mostly redshifted population near the main cluster (MC), which also shows a turbulent ICM. Despite their projected association with the MC core and NW substructure, both samples' velocities indicate they are not bound to them. Tail orientations give insight into orbital histories: NW tails point away from the cluster centre and often align with the merger axis, suggesting merger-driven stripping, while MC tails show neither pattern clearly. Tails are broadly westward, with MC tails tracing due west and NW tails shifted northwest, pointing to two distinct filamentary
accretion events for the NW and MC populations. Together, our results indicate enhanced RPS in the heart of A3667, driven mainly by infalling
galaxies accreted along nearby filaments interacting with the merger-driven turbulent environment.
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All authors Oğuzhan Çak{\i}r, Matt Owers, Gabriella Quattropani, Mina Pak, Stefania Barsanti, Joss Bland-Hawthorn, Julia Bryant, Scott Croom, Pratyush Kumar Das, Caroline Foster, Madusha Gunawardhana, Hyunjin Jeong, Jong Chul Lee, Joon Hyeop Lee, Yifan Mai, Kyuseok Oh, Sree Oh, Andrei Ristea, Sarah Sweet, Sujeeporn Tuntipong, Gurashish Bhatia, David Brodrick, Rebecca Brown, Elton Cheng, Robert Content, Fred Crous, Tony Farrell, Peter Gillingham, Ellen Houston, Jon Lawrence, Helen McGregor, Mahesh Mohanan, Seong-Sik Min, Barnaby Norris, Naveen Pai, Ayoan Sadman, Will Saunders, Sudarshan Venkatesan, Adeline Wang, Ross Zhelem, Jessica Zheng
Solar and Stellar Astrophysics
An Empirical Effective-Temperature Calibrations for Galactic B/A Supergiants
N.L.Vaidman, A.S.Miroshnichenko, Sh.T.Nurmakhametova et al. (+9 more)
We present empirical effective temperature Teff calibrations for
Galactic supergiants of spectral types B5-A5 based on optical spectra. The relationships were derived from a reference sample with adopted literature temperatures and use equivalent widths, central line depths, and ratios of selected spectral features as temperature indicators. Quadratic relationships are established for individual diagnostics and their ratios. Collectively, the calibrations span a Teff interval from 8 400 K to 14 700K, while the validity range of each relationships is individually specified. Detailed quantitative atmospheric analyzes remain indispensable for deriving physically consistent
stellar parameters. However, their application to extensive spectroscopic samples is observationally and computationally demanding. The empirical relationships presented here provide a homogeneous and readily applicable temperature scale for the characterization of
Galactic BA supergiants. The complete calibration tables, including fitted coefficients and uncertainty information, together with an interactive Python tool to apply the relationships, are publicly available through Zenodo. The reduced continuum-normalized spectra and associated metadata are published through a VO–compliant service of the Kazakhstan National Virtual Observatory.
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All authors N.L.Vaidman, A.S.Miroshnichenko, Sh.T.Nurmakhametova, S.Danford, S.A.Khokhlov, I.M.Izmailova, Ch.T.Omarov, S.V.Zharikov, D.E.Yakhiya, A.T. Agishev, A.A.Khokhlov, D.T.Agishev
High Energy Astrophysical Phenomena
Hybrid disc geometry for shocked accretion flows: Unveiling QPOs in black hole X-ray binaries
Monu Singh, Sudip Kumar Garain and Santabrata Das
We investigate the efficacy of semi-analytical global
accretion solutions in capturing the flow properties observed in two-dimensional numerical simulations of shocked
accretion onto black holes. A comparative analysis reveals that no single disc geometry adequately matches the simulation profiles across the entire radial domain. The pre-shock region exhibits closer agreement with the conical disc geometry, while the post-shock region is better described by the vertical
equilibrium disc, where enhanced thermal pressure leads to substantial vertical expansion. Motivated by these complementary behaviours, we introduce a hybrid disc geometry in which the pre-shock flow follows the conical solution and the post-shock flow attains vertical
equilibrium. This hybrid model satisfactorily reproduces both dynamical and thermodynamical properties of shocked
accretion flows with the predicted Mach number and temperature profiles closely matching the simulations and the inferred shock location differing by $\sim10\%$. Within this framework, we delineate the shock parameter space spanned by the energy ($\mathcal{E}$) and angular momentum ($\lambda$) of the flow for weakly and rapidly rotating black holes and investigate the possible origin of Quasi-periodic Oscillations (QPOs) in black hole X-ray binaries (BH-XRBs). We constrain flow parameters that reproduce observed QPO centroid frequencies ($\nu_{\rm QPO}$) demonstrating that oscillations of the shock front provide a self-consistent mechanism for both low and high frequency QPOs. Extending the analysis to ten
Galactic BH-XRBs, we demonstrate that the observed $\nu_{\rm QPO}$ are reproduced within physically plausible parameter ranges, which establishes shocked global
accretion solutions as a potentially compelling framework for interpreting
accretion driven temporal variability.
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Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph
Probing Sub-GeV Dark Matter with the Migdal Effect at JUNO
Stefano Scopel and Gaurav Tomar
We discuss the sensitivity of the JUNO
neutrino detector to the Migdal ionization signal triggered by
nuclear scattering events produced by sub-GeV weakly interacting massive particles (WIMPs). Exploiting JUNO's large target mass and the annual modulation effect we find that the aggregate rate from many independent and indistinguishable WIMP events in JUNO's
liquid scintillator can be isolated from the total dark rate of the photomultipliers, potentially providing for
spin-dependent interactions a world-leading sensitivity across the sub-GeV mass range.
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Solar and Stellar Astrophysics
Investigating the properties of nearby young moving groups using GaiaDR3
Mamta Lad, Ujjwal Krishnan, Blesson Mathew et al. (+4 more)
Moving groups, which are gravitationally unbound collections of
stars spread over large portions of the sky, pose challenges to their identification. Analyzing the three-dimensional spatial motion of
stars is one method to identify their members. Despite several studies in the past, a reliable and conclusive catalog of moving group
stars is currently lacking. Our objective is to present a most recent and updated catalog of nearby young moving group (NYMG) candidates in the
solar neighborhood and investigate their properties using updated science data from the
Gaia Data Release 3 (DR3). We searched for candidates of twelve NYMGs within a distance of 150 pc using
Gaia DR3. To determine the membership, we employed the
Bayesian algorithm BANYAN-Sigma. We compiled a total list of 3,153 NYMG candidates, of which 1,651 were new candidates. We also assessed the credibility of the literature defined 'Good-box' criterion with the latest comprehensive catalog of NYMGs from our study. We homogeneously estimated the ages of the NYMG candidates using
Gaia DR3 photometry data. The analysis revealed that our NYMG candidates display a large scatter on the CMDs resulting in a large range of estimated ages from isochrones. Additionally, we conducted an infrared (IR) excess analysis to identify disk candidates among our final sample. Our spectral energy distribution (SED) analysis found 51
stars with IR excess. We present a largely inclusive list of all the NYMG candidates within 150 pc of
Solar neighbourhood using
Gaia DR3. The wide range of ages obtained from isochrone fitting underscores the need for more robust age analysis techniques to accurately determine the ages of NYMG members. The presence of IR excess in the 51
stars confirms the existence of disks indicating that they could be potential candidates for
exoplanet detections.
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All authors Mamta Lad, Ujjwal Krishnan, Blesson Mathew, Raksha Olakal, Arun Roy, Sreeja Kartha, Vineeth Valsan
Astrophysics of Galaxies
Kinematics and Dynamics of the Open Cluster NGC 2302
Yuna Lee, Jongsuk Hong and Beomdu Lim
Open clusters are ideal observational testbeds to understand the dynamics of
stellar systems. We present a dynamical study of the young open cluster NGC 2302. The latest
Gaia data and $UBVIJHK_s$ photometric data are used in this study. A total of 117
stars are selected as the genuine members using the
Gaia data. This cluster is, on average, reddened by $<E(B-V)> = 0.24 \pm 0.06$ (s.d.). The ratio of total-to-selective extinction ($R_V$) in the direction of NGC 2302 is $2.8 \pm 0.1$. The cluster distance is determined to be $1.16 \pm 0.08$ kpc using
Gaia parallaxes. Theoretical isochrone fitting for $Z = 0.008$ on color-magnitude diagrams yields an age of $80 \pm 20$ Myr. The relative proper motions of individual members show no significant radial expansion or contraction. NGC 2302 contains a total
stellar mass of $333 \pm 48 M_{\odot}$. The one-dimensional velocity dispersion is approximately 0.26 km s$^{-1}$, which is comparable to the viral velocity dispersion of 0.27 km s$^{-1}$ derived from its total mass. Its relaxation time is estimated to be approximately 90 Myr, which is similar to the age of the cluster within the uncertainty in age estimation. Finally, we report a pattern of mass segregation in the radial distribution of
stellar masses. Our results suggest that NGC 2302 is virialized and currently approaching a state of dynamical relaxation. However, because no definitive evidence of kinetic energy equipartition is found, the possibility of the in-situ formation of high-mass
stars within the central region should be carefully considered.
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Astrophysics of Galaxies
Beyond Idealized PAHs: Infrared Signatures of Carbon-Chain Defects from Shock Synthesis
Xiaoting Tan, Zhao Wang, Zu-Jia Lu et al. (+2 more)
Polycyclic aromatic hydrocarbons (PAHs) are widely recognized as carriers of the aromatic infrared bands (AIBs). However, most spectral models rely on idealized structures that fail to capture the energetic environments of interstellar PAH formation. This work investigates the infrared (IR) signatures of PAHs formed under shock conditions and explores whether produced defective structures can explain observational features unpredicted by standard, idealized models. We combine two-stage reactive molecular dynamics simulations of PAH formation via condensation and shock processing with density functional theory spectral calculations, and compare our theoretical results with James Webb Space
Telescope (JWST) observations of NGC 7023 and MRK 1066. Shock processing produces PAHs featuring fullerene-like carbon skeletons and linear carbon-chain attachments. These structural defects yield distinct IR signatures, including prominent carbon-chain stretching features at 4.6-5.5 micron that is absent in ideal PAHs, and significantly enhanced out-of-plane skeletal modes in the 14.5-20 micron regime. Our findings attribute the observed 5.2 micron band in NGC 7023 and MRK 1066 to carbon-chain vibrations and the 15-18 micron emission to curved skeletal modes, providing observational support for the prevalence of defective, shock-formed PAHs in the interstellar medium.
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All authors Xiaoting Tan, Zhao Wang, Zu-Jia Lu, Houda Haidar, Dimitra Rigopoulou
High Energy Astrophysical Phenomena
On coordinate frames relevant for pulsar physics
Jyotijwal Debnath and Manjari Bagchi
Pulsars can be either isolated or binary (or even in triple) systems. Observational features of
pulsars are used to probe various aspects of fundamental physics, including emission mechanism, gravitational physics, etc. Theoretical models of various phenomena need different coordinate frames. Often different physical processes affect each other and we need to use multiple coordinate frames and relations between those. This short review presents an extensive set of coordinate frames and relations between those.
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High Energy Astrophysical Phenomena
Jun-Yu Shen, Hou-Dun Zeng and Qiang Yuan
Recent $\gamma$-ray observations indicate that the
proton spectra of
supernova remnants (SNRs) are well described by broken power laws, with both the spectral break energy, $E_{\mathrm{br}}$, and the low-energy spectral index, $\alpha$, exhibiting systematic
evolution with SNR age. The physical origin of these evolutionary trends and their implications for the
Galactic cosmic-ray (CR) population remain poorly understood. In this work, we develop the temporal
evolution model for
protons in SNRs by extending the semi-analytical framework of Zhang & Fang, in which both the maximum acceleration energy and the injection spectral index evolve with the dynamical
evolution of the remnant. The calculated
proton spectra reproduce the age-dependent trends of both $E_{\mathrm{br}}$ and $\alpha$ inferred from observations. We adopt the
proton spectrum at the onset of the radiative phase as the source spectrum for
Galactic CR propagation and incorporate the intrinsic dispersion of source spectral indices among SNRs. The resulting cumulative
Galactic proton spectrum is then calculated within a
diffusion model. The propagated spectrum agrees well with the observed CR
proton flux over a broad energy range, particularly above several tens of GeV. Our results provide a self-consistent framework linking the time-dependent
evolution of
proton acceleration in individual SNRs to the
Galactic CR
proton spectrum observed at Earth, and further support the long-standing hypothesis that SNRs are the dominant sources of
Galactic CR
protons below the knee.
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Astrophysics of Galaxies
A model for the enhanced production rate of early-type hypervelocity stars in the Galactic halo
Chunyang Cao, F.K. Liu, Xian Chen et al. (+1 more)
About twenty late B-type hypervelocity
stars (HVSs) traveling faster than the
Galactic escape velocity have been discovered in the
Galactic halo, many of which were ejected from the
Galactic center (GC). Recently, we have advocated that these HVSs most likely formed in the
nuclear star cluster (NSC) $150$–$500\, \rm{Myr}$ ago and were predominantly ejected via the gravitational slingshot of a past intermediate-mass black hole (IMBH) orbiting the supermassive black hole (SMBH) Sgr~A$^{*}$. Here we explore the constraints of the production rate of young HVSs on the
star formation region of the NSC. We propose that the young HVS progenitors are born in a lopsided eccentric disk that is comparable in radius to the NSC. By numerically tracking the orbital
evolution of disk
stars, we find that they undergo rapid angular momentum relaxation at formation due to eccentric disk instability, and that their slingshot interactions with the SMBH-IMBH binary at distances $\simeq 100\, \rm{au}$ produce HVSs at a rate of $10^{-5}$–$10^{-4}\, \rm{yr}^{-1}$. The rate is expected to trace the disk formation history, increasing with the accumulation of disk
stars and dropping rapidly after the
star formation stopped at $150\, \rm{Myr}$ ago. The rate is consistent with the observation and orders of magnitude higher than that expected for an old relaxed population in the literature, enhanced due to the gravitational torque from the non-spherical GC potential and radial velocity anisotropies of the disk
stars. Our results imply that young HVSs should have a distinct radial and angular distribution from old ones.
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All authors Chunyang Cao, F.K. Liu, Xian Chen, Shuo Li
Astrophysics of Galaxies
The MAGPI Survey: Emission Line Products Data Release and the Role of Spectroscopic Aperture Covering Fraction on the Balmer Decrement-Stellar Mass Relation
A. J. Battisti, E. G. M. Muller, E. Wisnioski et al. (+27 more)
The Middle Ages
Galaxy Properties with Integral field spectroscopy (MAGPI) survey is a Large Program on the European Southern Observatory Very Large
Telescope using the MUSE instrument. This paper presents the data release for the MAGPI emission line products and includes emission line maps for 836
galaxies at $0.05\leq z_\mathrm{spec}\leq 0.424$ ($\mathrm{H}\alpha$-window) and aperture-based emission line measurements for 2,607
galaxies at $0.05\leq z_\mathrm{spec}\leq 1.50$ (upper bound is [OII] cut-off), both based on the GIST software, for all 56 MAGPI fields. We use these data to examine
dust attenuation, which represents a major source of uncertainty in the derived properties of
galaxies that are critical to constrain models of
galaxy evolution. We examine the role that the spectroscopic aperture covering fraction ($f_c$) has on the relationship between the Balmer decrement ($\mathrm{BD}=F(\mathrm{H}\alpha)/F(\mathrm{H}\beta)$; a common proxy for
dust attenuation) and the total
stellar mass ($M_\star$). Several studies have suggested that the BD-$M_\star$ relation may be
redshift invariant; however, the compared surveys often have different $f_c$ due to their differing fibre or slit sizes that can cause systematic offsets. Our results indicate that $f_c$ has a significant impact on this relationship, due to
galaxies having negative BD radial gradients, which are more negative for more massive
galaxies at $z\lesssim0.4$. Comparing spectroscopic surveys with $\left<f_c\right> \gtrsim 0.5$, we find that the BD-$M_\star$ relation shows a preference for
redshift evolution and is roughly consistent with the behaviour of UV
stellar continuum attenuation
redshift evolution ($A_\mathrm{FUV}$-$z$), with the average
dust attenuation in
galaxies peaking at $z\sim1.2$ and decreasing at lower and higher
redshifts.
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All authors A. J. Battisti, E. G. M. Muller, E. Wisnioski, J. T. Mendel, C. Foster, C. D. P. Lagos, K. E. Harborne, I. U. Aalia, S. Barsanti, I. Breda, D. Calzetti, S. M. Croom, P. K. Das, A. Ferré-Mateu, T. Gao, E. Gjergo, K. Grasha, Y. Mai, A. Mailvaganam, T. Mukherjee, M. Mun, R.-S. Remus, G. Sharma, S. M. Sweet, S. Thater, L. M. Valenzuela, J. van de Sande, G. van de Ven, T. Zafar, B. Ziegler
Earth and Planetary Astrophysics
Stellar Abundances as Probes of Rocky Exoplanet Interiors: The Mantle Composition and Mineralogy of GJ 486b
Harshit Krishna, Asmit Gupta, Sneha Bhowmik et al. (+3 more)
Over the past three decades, hundreds of rocky
exoplanets have been discovered. Some of these show atmospheric signatures indicative of diverse chemical compositions. Interpreting these atmospheres requires a physically grounded understanding of planetary interiors, as interior composition and mineralogy govern the formation and
evolution of secondary atmospheres. Rocky terrestrial
exoplanets are expected to inherit the refractory composition of their host
stars, providing a direct pathway to constrain their bulk composition and mineralogy. However, a large fraction of these
planets orbit M-type
stars, whose compositions remain poorly constrained because of limited and uncertain
stellar abundance measurements. Here, we present a physically consistent framework that connects
stellar abundances to the interior structure and mineralogy of rocky
exoplanets by combining
stellar abundance inference, devolatilization modeling to estimate bulk and mantle elemental abundances, interior structure calculations to derive pressure-temperature profiles, and thermodynamic
equilibrium modeling of mantle mineralogy. We first
benchmark the framework against Earth and then apply it to the super-Earth GJ 486b using chemically consistent abundances derived from ensembles of similar M-
dwarf hosts. We find that GJ 486b likely hosts an iron-rich and silica-poor mantle relative to Earth while preserving the major mantle phase transitions. Sensitivity analyses show that the overall mineralogical structure is robust to variations in bulk composition and pressure-temperature profiles, with temperature primarily modulating phase proportions near key transitions. Finally, our results show that
stellar-abundance inference combined with devolatilization models constrains the interior composition of rocky
exoplanets and provides a foundation for linking planetary interiors to atmospheric characterization.
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All authors Harshit Krishna, Asmit Gupta, Sneha Bhowmik, Chandan K. Sahu, Sudipta Mridha, Liton Majumdar
High Energy Astrophysical Phenomena
An invariant energy release hierarchy in a repeating fast radio burst
X. Yang, S. B. Zhang, Y. Li et al. (+9 more)
Fast
radio bursts (FRBs) are luminous millisecond
radio transients whose physical origin remains unsettled. A key diagnostic is whether their burst-energy distributions retain characteristic physical scales that are intrinsic and temporally stable within an individual engine. Here we report a 3.2-year monitoring campaign of the hyperactive repeater FRB~20220529 with FAST and Parkes, yielding more than 1,300 bursts spanning nearly five orders of magnitude in spectral energy density. The cumulative burst-rate distribution is described by an exponential-plus-power-law (EXP+PL) form, linking a low-energy exponential component with characteristic scale (E_0) to a scale-free bright-end tail. This scale remains invariant despite the burst rate declining by more than an order of magnitude, revealing a stable dissipation scale decoupled from the source's macroscopic trigger activity. Within a magnetar interpretation, this phenomenology is consistent with localized sub-critical reconnection episodes coexisting with plasmoid-mediated
magnetic avalanches in a twisted magnetosphere. The invariant (E_0) constrains the dissipation region to the inner-to-middle magnetosphere and reveals a robust energy-release hierarchy beneath the variable activity of repeating FRBs, providing an observational
benchmark for relativistic reconnection in an ultra-magnetized
neutron-
star environment.
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All authors X. Yang, S. B. Zhang, Y. Li, D. Xiao, W. L. Zhang, J.-J. Wei, J.-J. Geng, J.-S. Wang, Y. P. Yang, F. Y. Wang, X. F. Wu, Z. G. Dai