High Energy Astrophysical Phenomena
Broadband Properties of the Harmonic of Type-C Quasi-periodic Oscillation in MAXI J1348-630
Xin-Lei Wang, Zhen Yan, Jun-Feng Wang et al. (+3 more)
Harmonics are common features of quasi-periodic oscillations (QPOs) in black hole X-ray binaries; however, their physical origins remain poorly understood. Using broadband Insight-HXMT data, we investigated the Type-C QPO harmonic in MAXI J1348-630. The harmonic is significantly detected exclusively during the hard intermediate state and displays prominent energy-dependent properties: while it is strong in the soft X-ray band (< 10 keV) with its fractional rms amplitude even exceeding that of the fundamental QPO, it is much weaker in the hard X-ray band (> 10 keV), where its rms amplitude is generally several times lower than that of the fundamental. Furthermore, the harmonic shows no significant phase coupling with the fundamental in the soft X-ray band, whereas strong coupling is present in the hard X-ray band. These features point to a complex, energy-dependent origin for the harmonic. We propose that the hard X-ray harmonic may arise from nonlinear distortion of the fundamental waveform within the corona, while the soft X-ray harmonic is likely produced via a distinct physical process, such as the reflection emission from the inner disk.
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All authors Xin-Lei Wang, Zhen Yan, Jun-Feng Wang, Fu-Guo Xie, Zhan-Yi Liu, Ren-Yi Ma
High Energy Astrophysical Phenomena
Population-Level Verification of the Black-Hole Area Law with First- and Second-Generation Black Holes
Shao-Peng Tang, Yin-Jie Li and Yi-Zhong Fan
Hawking's area
theorem states that the total event-horizon area of classical black holes can never decrease. Gravitational-wave tests of this law have so far focused on individual loud mergers, thus probing only a sparse subset of binary parameter space. Here we perform the first population-level test. We exploit the decomposition of the coalescing black holes in the latest gravitational-wave catalogue into a low-
spin subpopulation of
stellar-collapse origin and a high-
spin subpopulation assembled through hierarchical mergers of the former. If the high-
spin black holes are merger remnants, the area
theorem requires their horizon areas to exceed the total pre-merger areas of the low-
spin binaries. Using parameter estimation restricted to the inspiral of 241 events, so that no merger-ringdown information enters the inference, we find that both peaks of the horizon-area distribution of second-generation black holes lie above their first-generation counterparts. The displacement is significant at each peak ($2.1$–$3.7\sigma$), and when we tie the two subpopulations with a single common shift, an area decrease is excluded decisively ($\gtrsim5.0\sigma$). The second law of black-hole mechanics thus holds statistically across the quasicircular, moderately spinning mergers that dominate current catalogues, which in turn underpins the robustness of our classification of
stellar-collapse and hierarchical-merger black holes.
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Earth and Planetary Astrophysics
From Earth Meteors to Mars: Predicting Where to See the First Martian Meteors
Maximilian Vovk, Peter G. Brown and Denis Vida
Predictions of optical meteors at Mars have largely relied on classical single-body ablation models, despite high-resolution terrestrial observations showing that mm-sized meteoroids frequently fragment. This study quantifies how fragmentation alters the predicted brightness and peak-luminosity altitudes of sporadic mm-sized meteoroids in the Martian atmosphere and evaluates the single-body approximation as a reference baseline. Physical properties were inferred for 144 sporadic meteoroids observed on Earth using dynamic nested sampling with the erosion-fragmentation model. The resulting best-fit meteoroids were then re-simulated under Martian atmospheric conditions to generate predicted light curves. Because the physical trigger of fragmentation onset remains uncertain, three hypotheses were tested based on atmospheric mass density, dynamic pressure, and total accumulated heat. The results were also compared with predictions from a single-body ablation model. The data-driven simulations predict peak absolute magnitudes of $M_{\rm peak}\sim$ 2 - 7 for Martian meteors spanning diameters of 0.4 - 10 mm and entry speeds of 10 - 56 km/s. We find most events are luminous between $\sim$ 55 and 110 km heights. Relative to the single-body ablation baseline, the fragmentation-based predictions are brighter by $\sim$ 0.8 mag at peak brightness and concentrate luminosity within a narrower vertical range ($\sim$ 17 km instead of 36 km). The modelling accounting for fragmentation also produce shorter luminous trails ($\sim$ 20 km instead of 45 km). The resulting altitude-brightness maps provide observation-ready guidance for future Mars missions, while the fragmentation-based framework supports the interpretation of meteoroid-related ionospheric metal layers and improvements to Mars meteoroid-environment models.
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Instrumentation and Methods for Astrophysics
Millimeter-wave adaptive optics: Demonstrating closed-loop correction for lowest Zernike modes
Yoichi Tamura, Akio Taniguchi, Kotaro Iwakami et al. (+15 more)
We report on a five-element prototype wavefront sensor for millimeter-wave adaptive optics (MAO), enabling closed-loop correction of tip-tilt and defocus via secondary mirror (M2) displacement. MAO is essential for large ground-based millimeter/submillimeter
telescopes to maintain surface accuracy under wind and thermal distortions. Our sensor, based on
radio interferometry, measures excess path lengths from the primary mirror to a focal-plane receiver. A previous two-element prototype achieved < 10 um accuracy at the Nobeyama 45 m
telescope. The new five-element system, operating at 20 GHz, was installed on the same
telescope. A “Moon-edge” experiment confirmed detection of wavefront gradients through strong correlation with continuum flux. Implementing a PI controller closed the sensor-M2 loop, stably suppressing the lowest Zernike modes. This approach establishes a foundation for metrology in future large-aperture submillimeter facilities such as AtLAST/LST.
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All authors Yoichi Tamura, Akio Taniguchi, Kotaro Iwakami, Ichiro Jikuya, Shion Takeno, Sachiko K. Okumura, Masaki Sakakibara, Akinobu Miyake, Masato Hagimoto, Kianhong Lee, Chihiro Imamura, Sho Fujisawa, Shutaro Inui, Masato Kato, Ryohei Kawabe, Mikio Kurita, Nozomi Okada, Juri Yamanaka
High Energy Astrophysical Phenomena
Cosmogenic neutrinos from FRII galaxies as potential origin of the ultra-high-energy KM3-230213A event
Denis Allard, Bruny Baret, Noémie Globus et al. (+1 more)
Aim : We investigate whether the ultra-high-energy
neutrino KM3-230213A can be interpreted as a cosmogenic
neutrino produced by ultra-high-energy
cosmic rays (UHECRs) accelerated in the lobes of FRII
radio galaxies. Method : We model the UHECR, cosmogenic
neutrino and
photon fluxes expected at Earth using a recent luminosity-dependent density
evolution of
radio galaxies, empirical relations between
radio luminosity and jet kinetic power, and standard assumptions for the UHECR output of FRII lobes. The FRII contribution to the UHECR population is derived self-consistently from the observed luminosity function, rather than imposed as a fixed normalization. The propagation of UHECRs and the production of secondary particles are computed with well-established numerical tools. Results : The predicted cosmogenic
neutrino flux is compatible with that inferred from the detection of KM3-230213A, while remaining consistent with current UHECR and gamma-ray constraints. According to our models, the full GRAND observatory ($200\,000~\rm km^2$) should detect between $\sim50$ and $\sim135$
neutrinos above $10^{17}$~eV in ten years, allowing the diffuse UHE
neutrino spectrum to be characterized. In contrast, the detection of individual FRII sources or statistically significant correlations with FRII catalogs is likely to remain challenging. At the highest energies, UHECR composition and anisotropy measurements, in particular those related to the nearby
radio galaxy Cygnus~A, should provide complementary tests of this scenario. More generally, progress will likely rely on the combination of multimessenger observations with improved astrophysical constraints on particle acceleration and jet composition in FRII
radio galaxies.
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All authors Denis Allard, Bruny Baret, Noémie Globus, Etienne Parizot
Cosmology and Nongalactic Astrophysics
Nonlinear velocity power spectrum: modeling the cosmological dependence on the Hubble constant and cold dark matter density
Francesca Lepori, Ruth Durrer, Martin Kunz et al. (+3 more)
In this paper we present a semi-analytical model for the velocity power spectrum in $\La$CDM cosmology for wave numbers $k<1/$Mpc. We mainly concentrate on the dominant divergence part but also present some results on the vorticity contribution. We divide cosmological parameters into
evolution and shape parameters and model the dependence of the
evolution parameter $h$ and of the shape parameter $\om_{\rm cdm}$ with an accuracy better than 2.5%. A surprising finding of our study is that the velocity power spectrum becomes independent of $\om_{\rm cdm}$ on nonlinear scales. A python implementation of the model is publicly available.
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All authors Francesca Lepori, Ruth Durrer, Martin Kunz, Francesco Sorrenti, Julian Adamek, Davide Piras
Cosmology and Nongalactic Astrophysics
Brightest group and cluster galaxies as indicators of relaxation
K. Kelder, P. Heinämäki, P. Nurmi et al. (+2 more)
Context.
Galaxy groups and clusters are widely used to probe the
evolution of the
cosmic web and cosmology, while assuming that they are relaxed. Aims. We identify the properties of the brightest
halo galaxies (BHGs) that can be used to predict the most likely sample of dynamically relaxed host
halos. Our work combines thoroughly studied
galaxy clusters with less frequently analysed groups. Methods. Our analysis was based on data from the IllustrisTNG simulations. We considered several observationally motivated parameters, including the offset of the BHG from the potential well of the host system ($d_\text{off}$) and from the r-band luminosity centre ($d_\text{lum}$), the distance between the brightest and second-brightest
galaxies ($d_{12}$), and the r-band magnitude gap between them ($\Delta m_{12}$). The primary analysis was performed at
redshift $z=0$, with an additional investigation of the
redshift evolution of
halo relaxation up to $z=1$. The observable proxies were applied to construct a
halo mass function (HMF), which was then compared to the HMF of the relaxed sample defined from 3D information commonly used in theoretical approaches. Results. We find that $d_\text{off}$ and $\Delta m_{12}$ are effective indicators of group and cluster relaxation, particularly when used in combination. The selection criteria of $d_\text{off}<0.05~R_{200}$ and $\Delta m_{12}>1.6$ mag allowed us to reproduce an HMF that closely matches that of the relaxed
halo population. These criteria can be applied to observations up to $z\sim0.2$ within a mass range $\text M_{200}\geq10^{12.5}\text M_\odot$ ($\text M_\text{*, BHG}\gtrsim10^{10.9}\text M_\odot$), including groups and clusters in the selection. In this mass range, $15-23\%$ of the systems are considered fully relaxed at $z=0$. The fraction of relaxed
haloes decreases with
redshift up to $z\sim0.4$, after which the decrease is far slower.
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All authors K. Kelder, P. Heinämäki, P. Nurmi, E. Tempel, M. Einasto
Instrumentation and Methods for Astrophysics
Tradeoff between segment density and IWA for high-contrast imaging of exoplanets with a large segmented space mission
Lucie Leboulleux, Raphaël Pourcelot, Laurent Pueyo et al. (+1 more)
Imaging Earth-like
exoplanets with coronagraphs on future large segmented space
telescopes such as the Habitable Worlds Observatory requires contrasts down to $10^{-10}$ at separations below 100 mas, imposing segment phasing control down to a few picometers. We evaluate how this constraint can be relaxed by optimizing
telescope and instrument design, quantifying the impact on performance stability under segment phasing aberrations. We propose a system-level approach, adjusting the primary mirror
segmentation and the focal-plane mask size (inner working angle). We compare the passive robustness to segment phasing errors across systems, and the ability of a Zernike low-order wavefront sensor to reconstruct aberrations and recover target performance. Increasing the focal-plane mask radius or decreasing segment count improves both passive robustness and sensor reconstruction: Increasing the mask radius from 3.5 to 6.5{\lambda}/D relaxes phasing constraints by up to a factor 4 near the IWA, and reducing the segment count from 85 (5 rings) to 7 (1 ring) relaxes them by up to a factor 2; The same mask radius increase also doubles, on average, the sensor's sensitivity to
photon noise across segment piston, tip, and tilt modes. To conclude, jointly optimizing the
segmentation scheme and mask size, so the low-order PSD envelope is blocked by the mask, can significantly relax phasing requirements, complementing active correction, with direct implications for HWO.
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All authors Lucie Leboulleux, Raphaël Pourcelot, Laurent Pueyo, Bryony Nickson
Solar and Stellar Astrophysics
CO rotational line emission in very red carbon stars in the Magellanic Clouds
M.A.T. Groenewegen, A. Nanni, M.L. Boyer et al. (+11 more)
Stars of low and intermediate initial mass lose most of their
stellar mass at the end of their lives during the asymptotic
giant branch (AGB) phase. Determining their gas and
dust mass-loss rates (MLRs) is crucial for quantifying the contribution of evolved
stars to the life cycle of
dust and gas in the Universe. The Atacama Large Millimeter/submillimeter Array was used to observe 38 carbon
stars (C
stars) in the large Magellanic cloud (LMC) and three C
stars in the small Magellanic cloud (SMC) in the CO J= 2-1 line. Line profiles were fitted to derive
stellar velocities and wind-expansion velocities (Vexp). CO emission is detected in two C
stars in the SMC and 33 C
stars in the LMC. This is the first detection of carbon monoxide around an AGB
star in the SMC. One object in the LMC shows emission in $^{13}$CO. The wind-expansion velocity ranges from \sim7.5 to \sim30 km/s. Archival data were used to determine the pulsation periods as well as construct and model the spectral energy distributions using two
dust radiative transfer codes. Mass-loss rates were independently derived from these two codes as well as from the intensity of the CO line, using a simple formula. On average, the
dust-based MLRs higher than the MLRs based on the CO line by a factor of 1.6. Additional CO data in other transitions, combined with proper modelling, is required to further investigate this possible discrepancy. Mass-loss rates, pulsation periods, and expansion velocities were compared to a sample of
Galactic C
stars. There is a strong bias, as the Magellanic Cloud targets sample the highest MLRs and luminosities, yet they represent only a minority of
stars in a
Galactic sample. Comparing this sample with a similarly extreme set of
Galactic stars with periods longer than 500 days, we identify no correlation between
metallicity and either the MLR or Vexp.
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All authors M.A.T. Groenewegen, A. Nanni, M.L. Boyer, L. Decin, S.R. Goldman, K. Justtanont, F. Kerschbaum, I. McDonald, H. Olofsson, R. Sahai, G. C. Sloan, J. Th. van Loon, W.H.T. Vlemmings, A.A. Zijlstra
Solar and Stellar Astrophysics
Detection and Characterization of Microlensing Events due to Isolated Black Holes towards the Magellanic Clouds in the Rubin Observations
Sedighe Sajadian and Martin Makler
Gravitational microlensing surveys potentially discover isolated black holes (IBHs) at large distances through their gravitational effects on apparent brightness and motion of collinear
stars. Here, we study detecting and characterizing IBHs within the mass range $[3,~5000]M_{\odot}$ with either
stellar or dark matter origins in the upcoming observations by Vera~C.~Rubin Observatory towards the Large and Small Magellanic Clouds (LMC and SMC). We consider four lens mass functions (MFs:~$dN/dM\propto M^{-\beta}$ for $\beta=0,~0.5,~1,~2$), and generate long-duration microlensing events due to IBHs detectable by Rubin. By assuming the fraction of IBHs's mass in total
Galactic mass as $\mathcal{F}$, Rubin potentially detects $\sim0.3,~\rm{and}~2$ microlensing events towards SMC and LMC due to IBHs if $\beta=1,~\rm{and}~\mathcal{F}=5\times10^{-3}$. These IBHs are inside our
galaxy with the probability $\gtrsim70\%$. These events have on average $\theta_{\rm{E}}\sim30-50~\rm{mas}$, so that the probabilities of resolving their
lensing-induced images through the Rubin astrometric observations are $\sim1.4,~\rm{and}~16.3\%$ towards LMC and SMC. In $\sim1,~5.2\%$ of these events their astrometric deflections are realizable. The probabilities of discerning their parallax are $\sim40,~25\%$. We evaluate relative errors with simulating synthetic data points and by assuming the true models as the best-fitted ones. We conclude for a log-uniform MF for $\lesssim0.1,~\rm{and}~0.3\%$ of photometrically detectable microlensing events towards in LMC and SMC the relative errors in the lens mass, distance and velocity are $\lesssim3\%$. We calculate the number of detectable IBHs versus by assuming their complete contribution of compact objects in
halos' darkmatter, and conclude Rubin specifies $95\%$~C.L. upper-limit on IBHs exclusion by masses $\lesssim208,~8M_{\odot}$ for $\mathcal{F}\simeq4\times10^{-3}$.
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Solar and Stellar Astrophysics
Machine Learning in Application to Automatic Noise Processing of Solar Spectrograms
I. I. Yakovkin, A. O. Bartenev and N. V. Petrova
In this paper, a machine learning approach for processing
solar spectral data were developed. Its performance was demonstrated using the example of the limb
solar flare on July 17th, 1981. The results indicated that machine learning can be effectively utilized to transform between differently digitized spectra, fill gaps in unique experimental data, and undertake spectrum cleaning. Specifically, convolutional neural networks were devised to transform between reflective and transmissive scans of a
solar flare spectrogram. This can be a convenient technique for treating the spectrograms of unique
solar events, most notably increasing the proportion of observational spectra that can be further analyzed. Namely, in subsequent research, we will be able to confidently incorporate data such as that captured on the edges of spectrograms, which was previously deemed insufficiently reliable due to limitations of available processing techniques. This will consequently increase the number of spectral lines studied for certain observed events, which is paramount for constructing physical models, as the spectral peculiarities are expected to manifest consistently across different spectral lines. The developed approach also notably facilitates the detection and removal of
impurities in the spectrograms. Previously, each distinct feature in the spectra was manually scrutinized to check its integrity in order to be excluded if identified as an
impurity, such as a scratch or a
dust particle. By employing the suggested protocol for treating the spectrogram, which includes scanning the spectrogram using multiple distinct techniques and then leveraging machine learning for comparison, the process of excluding
impurities can now be automated. Furthermore, the spectrum areas affected by such exclusions can be restored, enabling further analysis.
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High Energy Astrophysical Phenomena · Cross-listed from gr-qc
Limiting cases of second-order moments of relativistic stars and their universality
Koutarou Kyutoku
Extending the work presented in a workshop “From
Quarks to
Neutron Stars: Insights from kHz gravitational waves”, we discuss some limiting cases of the moment of inertia,
tidal deformability, and
spin-induced quadrupole moment for relativistic
stars. First, conjecturing that a hierarchy of the length scale is the key to proposed universality among these second-order moments, we revisit the relation for incompressible relativistic
stars (known as Schwarzschild's interior solution) as a candidate of the possible stiff limit. Second, we present the limiting form for the weak-field limit. In particular, we demonstrate how relativistic computations of
tidal deformation are related to the traditional Newtonian counterpart, which might not have been presented explicitly in the literature.
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Astrophysics of Galaxies
RIOJA. Environmental Effects on Stellar Populations and Ionized Gas in a Protocluster at $z=7.88$
Wataru Osone, Takuya Hashimoto, Javier Álvarez-Márquez et al. (+23 more)
Protoclusters in the epoch of reionization provide key laboratories for investigating how environment shapes early
galaxy formation and
evolution, and may also have contributed to
cosmic reionization. We analyze 23 member
galaxies of A2744-z7p9OD, a protocluster at $z=7.88$, using JWST/NIRCam and NIRSpec to investigate their
stellar population properties, rest-frame UV sizes, and ionized-gas properties. We also quantify the internal structure of A2744-z7p9OD using the projected distance to the most massive
galaxy ($D_{\rm YD4}$), and to the nearest neighbor ($D_{\rm nei}$), as global and local environmental indicators, respectively.
Stellar mass, SFR on a 100 Myr timescale,
dust attenuation, and
galaxy size show significant correlations ($p<0.05$) with $D_{\rm YD4}$, but not with $D_{\rm nei}$, suggesting that these properties are primarily linked to the global protocluster structure. The member
galaxies also show a large
galaxy-to-
galaxy variation in R23 ($=\log{(([\mathrm{O}\text{\textsc{iii}}]\lambda\lambda4960,5008\rm{\AA}+[\mathrm{O}\text{\textsc{ii}}]\lambda\lambda3727,3730\rm{\AA})/\rm{H}\beta)}$), implying inhomogeneous chemical enrichment in the protocluster environment. O32 ($=\log{([\mathrm{O}\text{\textsc{iii}}]\lambda5008\rm{\AA}/[\mathrm{O}\text{\textsc{ii}}]\lambda\lambda3727,3730\rm{\AA})}$) correlates with $D_{\rm YD4}$, indicating that the core region is characterized by low-ionization gas. Together with the non-detection of Ly$\alpha$ emission, the possible neutral-gas reservoir traced by ALMA [Cii]~$158\mu$m emission, and evidence for high-column-density neutral hydrogen in the core, this suggests a neutral-gas-rich protocluster core where the current escape of ionizing
photons may be suppressed, even in a overdense environment during the EoR.
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All authors Wataru Osone, Takuya Hashimoto, Javier Álvarez-Márquez, Luis Colina, Akio K. Inoue, Ken Mawatari, Yuma Sugahara, Carmen Blanco-Prieto, Takeshi Hashigaya, Takahiro Morishita, Massimo Stiavelli, Santiago Arribas, Tom J. L. C. Bakx, Daniel Ceverino, Alejandro Crespo Gómez, Yoshinobu Fudamoto, Masato Hagimoto, Asahi Hamada, Rui Marques-Chaves, Yurina Nakazato, Hideki Umehata, Hidenobu Yajima, Hiroshi Matsuo, Naoki Yoshida, Yi W. Ren, Yoichi Tamura
Astrophysics of Galaxies
Coronal gas excitation as a tracer of supermassive black hole mass: on the mid-IR coronal [Ne v] lines
J. S. Elford, A. Prieto and A. Rodríguez-Ardila
Coronal lines (CL) may be a reliable proxy of supermassive black hole (SMBH) masses in active
galactic nuclei (AGN) because the production of these high ionisation potential (IP) lines is sensitive to the shape of the ionising continuum which, for a thin
accretion disc, relies on the black hole mass. In this work we study the connection between the [Ne\,v] coronal lines and the SMBH mass. We analyse the Spitzer spectra of a sample of 27 AGN spanning three orders of magnitude in SMBH mass. Fluxes and the electron density in the coronal gas medium were measured after fitting Gaussians to both the $\rm [Ne\,v]14\mu m$ and $\rm [Ne\,v]24\mu m$ lines where detected at high signal to noise. Line fluxes were normalised to the Br$\gamma_{\rm broad}$ emission from the broad line region. We found strong correlations between the $\rm [Ne\,v]14\mu m/Br\gamma_{\rm broad}$ and $\rm [Ne\,v]24\mu m/Br\gamma_{\rm broad}$ line ratios and the SMBH mass. For this sample of 27 AGN we find scatters of 0.54 and 0.53 dex, respectively. These correlations support the theory that the coronal gas excitation is sensitive to a range of SMBH masses because of the dependence on the shape of the ionising continuum. The electron densities of the coronal medium are of the order 1000$\rm cm^{-3}$ supporting their
nuclear origin. A comparison with density values derived from JWST for a subsample of objects confirm this conclusion. These results further demonstrate the ability to use CL as a SMBH mass proxy, allowing for accurate SMBH mass measurements in AGN.
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Solar and Stellar Astrophysics
Characterizing Stellar Flares in Ariel Targets: Activity Analysis and Transit Contamination
G. Galletta, S. Colombo and G. Micela
Stellar flares are sudden releases of
magnetic energy that can distort
exoplanet transit photometry and transmission spectroscopy, biasing
planet radius estimates, transit timings, and atmospheric characterization. Understanding
flare activity in Ariel targets is therefore essential to identify
stars where
flares may compromise observations and to characterize the radiation environment affecting atmospheric escape and photochemistry. We analyzed 290 Ariel target
stars using TESS light curves.
Flares were identified via iterative Gaussian process detrending, and their energy distributions were modeled with two-segment power laws. We performed injection-recovery tests by adding synthetic
flares to detrended light curves and running the full pipeline to quantify completeness and detection biases. We detected 15,857
flares across 1,638 TESS sectors, with 2-86 events per sector. We defined a normalized
flare index GF.01 to compare activity across
stellar luminosities. Near 3% of the sample exhibits enhanced
flare activity (GF.01 > 1). AU Mic and HD 28109 show a high likelihood of
flare contamination during transit observations. GF.01 correlates negatively with
stellar bolometric luminosity, indicating higher relative
flare output in lower-luminosity
stars. AU Mic is an extreme case: four of five observed transits of AU Mic b are affected by
flares, consistent with statistical expectations. We validate the framework by comparing predicted
flare-contamination probabilities with observed
flare occurrences in a representative subset of transits, finding agreement within uncertainties. These results confirm that energetic
flares can significantly impact transit observations and provide quantitative guidance for Ariel target selection and analysis strategies.
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Instrumentation and Methods for Astrophysics
A NICE (Nulling Interferometry Cryogenic Experiment) update: Beyond 1e-5 and towards cryogenic operation
Jonah T. Hansen, Thomas Birbacher, Germain Garreau et al. (+10 more)
The Nulling Interferometry Cryogenic Experiment (NICE) is a mid-infrared laboratory testbed at ETH Zürich that aims to not only reproduce the deep ($<1\times10^{-5}$) broadband nulls of the nulling testbeds of the early 2000s, but also at the required sensitivity levels expected for the LIFE space mission. This sensitivity enforces the experiment to go cryogenic at temperatures around 15 K; an ambitious task for an ultra-precise interferometer. We share our results of the ambient precursor experiment, demonstrating repeatable $<1\times10^{-5}$ nulls at a single wavelength and high throughput, and investigations into the nulling performance across a broader bandpass and with dual polarisation states. We will also highlight the push towards cryogenic operation, with the instalment of a new 15 K test cryostat that will inform our choices of materials and optomechanical mounting techniques.
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All authors Jonah T. Hansen, Thomas Birbacher, Germain Garreau, Julio Pino-Jiménez, Emilie Bouzerand, Felix A. Dannert, David Eglin, Lee Feinberg, Adrian M. Glauser, Maximilian Kirchhoff, Oliver Pitz, Eckhart Spalding, Sascha P. Quanz
Instrumentation and Methods for Astrophysics
Cryogenic characterisation for the Nulling Interferometry Cryogenic Experiment (NICE)
Jonah T. Hansen, Emilie Bouzerand, Adrian M. Glauser et al. (+11 more)
The Nulling Interferometry Cryogenic Experiment (NICE) is an experimental testbed for the beam combiner of the Large Interferometer For
Exoplanets (LIFE) space mission. Until now, progress on NICE has been confined to an ambient bench, where we have recorded progress in deep ($<10^{-5}$) nulls at wavelengths between 4 and 5 microns at 300 K. However, the ultimate goal and requirement of NICE is to repeat these measurements at the sensitivity levels expected for a planetary system, requiring deep cryogenic conditions at 15 K. Here, we describe the “Ice Cube” cryostat, a small version of the future NICE cryostat that is used for component and subsystem level cryogenic testing. This is interfaced with a measurement setup using a segmented aperture interferometer and a wavefront sensor. We will also describe the testing campaign for understanding the material and mounting challenges that will be faced when translating the warm bench to cryogenic operations.
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All authors Jonah T. Hansen, Emilie Bouzerand, Adrian M. Glauser, Bastien Rouzé, Noah Stocker, Walter Bachmann, Marcel Baer, Cindy Bellanger, Thomas Birbacher, Germain Garreau, Julio Pino-Jiménez, Jerome Primot, Eckhart Spalding, Sascha P. Quanz
High Energy Astrophysical Phenomena · Cross-listed from gr-qc
Exceptional points of the Schwarzschild spectrum under local potential perturbation: The Princess and the Pea
Mohamed Ould El Hadj and Sam R. Dolan
Black-hole quasinormal modes (QNMs) may coalesce at exceptional points (EPs) in the frequency spectrum. We study EPs and their phenomenology for gravitational perturbations of a Schwarzschild black hole whose Regge-Wheeler potential is perturbed by a localized delta-function of amplitude $\epsilon$ at radius $r_0$. For real $\epsilon$, we find infinite families of discrete EPs. Each family approaches a distinct unperturbed QNM overtone frequency as $r_0$ grows large. Under perturbation at fixed $r_0$, we find that neighboring QNM overtones migrate in the complex plane to meet at these EPs, with the higher overtone moving further. We derive large-$r_0$ asymptotics, finding that EPs have (asymptotically) equal spacing in the tortoise coordinate, and that EP amplitudes $\epsilon$ can be exceedingly small, decaying exponentially according to a rule governed by the complex frequency of the unperturbed QNM. Using quadratic approximations around EPs and high-precision numerical methods, we investigate a range of phenomena in the model: square-root splittings, avoided crossings and hyperbolae, hysteresis and
geometric phases generated by encircling an EP, adiabatic invariants, deformed Cassini ovals and cusp-like trajectories, as well as the lemniscate geometry of the excitation factors. We then replace the delta-function perturbation by a finite-width Gaussian, verify the persistence of the EP structure, and show that varying the width extends isolated EPs into exceptional lines in parameter space. Finally, we study the response to initial data and find that, although a weak perturbation can substantially reconfigure the QNM spectrum, the corresponding time-domain response remains perturbative. This contrast is captured by a re-interpretation of the tale of The Princess and the Pea.
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High Energy Astrophysical Phenomena
Multipolar Neutrino Radiation in Binary Neutron Star Mergers: Angular Structure, Rotational Variability, and Implications for Electron Fraction
Kutay Ar{\i}nç Çokluk, Albino Perego, Federico Maria Guercilena et al. (+1 more)
The angular structure and temporal variability of
neutrino emission from binary
neutron star mergers are characterized using fully general-relativistic simulations with energy-integrated M1
neutrino transport across a representative set of equations of state, total masses, and mass ratios. The angle-dependent
neutrino energy flux is extracted on a spherical surface outside the remnant and decomposed into spherical harmonics to quantify its multipolar content and
evolution. Following the initial post-merger transient, the
neutrino radiation flux approaches an axisymmetric configuration dominated by a strong quadrupolar component, producing persistent polar flux enhancement and equatorial suppression due to
torus shadowing. The dipolar contribution remains subdominant, indicating the absence of sustained one-sided emission. The degree of anisotropy increases with mass asymmetry and for softer equations of state, reflecting the compactness and morphology of the remnant–disk system. Superimposed on this time-averaged geometry, coherent azimuthal modulations associated with the $m=1$ mode are identified.
Fourier analysis reveals a characteristic frequency of $\sim 0.6$–$0.7$ kHz, consistent with differential rotation in the remnant and inner disk layers, indicating a dynamical coupling between rotational structure and
neutrino emission variability. Finally, we quantify how the same quadrupole-dominated radiation geometry induces a latitude-dependent
equilibrium electron fraction. The polar material is driven close to the
neutrino-
equilibrium target, whereas equatorial material remains systematically more
neutron-rich and below
equilibrium.
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All authors Kutay Ar{\i}nç Çokluk, Albino Perego, Federico Maria Guercilena, Kadri Yakut
Instrumentation and Methods for Astrophysics
Direct Imaging and Gradient-Based Analysis of the 12 August 2026 Partial Solar Eclipse from a Freely Rotating High-Altitude Balloon
Bjoern Poppe, Enno Gronewold, Matti Gehlen et al. (+7 more)
We report a proof-of-concept observation of the partial
solar eclipse of 12 August 2026 using a freely rotating high-altitude balloon launched from Oldenburg, northern Germany. The payload carried two Insta360 ONE RS cameras equipped with 4K Boost wide-angle lenses; covered by filter material taken from a BRESSER eclipse viewing glass. Interval photographs were acquired every 10 s at ISO 800 and 1/1000 s. Of approximately 1,300 images, 21 contained a directly visible image of the eclipsed Sun, spanning 19:19:15-20:38:21 CEST and both sides of the local eclipse maximum. To test whether quantitative eclipse information could be recovered from these small, non-stabilized wide-angle images, the visible
solar area was estimated using a two-dimensional gradient-based
solar edge analysis and normalized to the first observation. The image-derived obscuration followed the independently calculated eclipse geometry with Pearson r = 0.959, a mean absolute difference of 9.5 percentage points, and an RMSE of 11.5 percentage points. Systematic deviations are consistent with the limitations of an uncalibrated action-camera system, including point-spread function, field-dependent lens response, filter geometry, and camera-to-camera differences. The results demonstrate that passive payload rotation can yield both visually useful and semi-quantitative direct eclipse observations without active
solar pointing, and define a calibration strategy for future balloon-borne eclipse measurements.
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All authors Bjoern Poppe, Enno Gronewold, Matti Gehlen, Jona Schrader, Delia Gauk, Lisa Cordes, Maike I. Schmitz, Peter Schoenfeld, Simon Jaeger, Gerhard Drolshagen
Earth and Planetary Astrophysics
Optical-NIR Multi-band Photometric Analysis and Characterization of Giant Exoplanets with CPI-C
Yiming Zhu, Gang Zhao, Xi Zhang et al. (+4 more)
We present a multi-band photometric approach to characterize
giant exoplanets, which represents one of the anticipated core scientific outcomes of Cool
Planet Imaging Coronagraph (CPI-C). CPI-C operates with two observational channels covering visible and near-infrared wavelengths, each equipped with four broadband filters. The
planet–
star flux ratio integrated over each filter bandpass is calculated for photometric analysis. For cool
planets observed in the visible bands, the data are primarily used to fit the overall spectral shape and methane-induced modulation, providing sensitivity to
metallicity- and cloud-dependent spectral variations while constraining the reflected-light spectral shape and the combined scaling involving
planet radius, orbital separation, and orbital phase. In the near-infrared bands, which probe thermal emission, the data help to better constrain fundamental planetary parameters including the effective temperature, radius, surface
gravity and mass. For a synthetic
giant planet with measurable reflected-light and thermal-emission components, the combined VIS4+NIR4 data provide tighter same-target constraints than either filter set alone, especially for the
planet radius and cloud sedimentation parameter. Our simulations incorporate realistic instrument throughput, detector noise, and residual speckle noise. The results demonstrate that the eight-band design spanning visible to near-infrared wavelengths supports reflected-light diagnostics, thermal-emission characterization, and joint optical–NIR analysis of
giant exoplanets within CPI-C science observations.
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All authors Yiming Zhu, Gang Zhao, Xi Zhang, Gang Wang, Bingli Niu, Zhonghua Lv, Jiangpei Dou
Earth and Planetary Astrophysics
The dust-rich, gas-depleted protosolar disk as the birthplace of chondrules
Sota Arakawa, Hidekazu Tanaka, Toshihiko Kadono et al. (+3 more)
Chondrules are the primary components of primitive meteorites known as chondrites, and understanding their formation and accumulation is essential for elucidating the history of
planet formation in the
Solar System. Although a variety of chondrule formation mechanisms have been proposed, it remains challenging to satisfy the key constraints on chondrule abundance, formation timing, and mineralogical and chemical characteristics within a single model. In particular, the planetesimal bow-shock model, once considered one of the leading candidates, now faces a fundamental difficulty: Jupiter's formation likely depleted gas in the protosolar disk, potentially lowering the gas density below that required for efficient chondrule formation by planetesimal bow shocks. Here we propose an alternative mechanism that can occur in a gas-depleted environment: heavy bombardment of eccentric planetesimals by debris
dust. After Jupiter formed in the protosolar disk, the region interior to its orbit became gas-depleted, leading to the formation of a geometrically thin debris-
dust layer. When planetesimals enter the
dust layer at high speed, large quantities of molten silicate droplets are produced. These droplets cool and solidify into chondrules and are reincorporated into the
dust layer. Using analytical calculations, we find that our model can potentially explain the abundance, formation timing, and mineralogical and chemical characteristics of chondrules. This study links the formation of Jupiter and the accompanying
evolution of the protosolar disk to the origin of terrestrial
planets, asteroids, and meteorites, thereby offering a new framework for the formation of the
Solar System.
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All authors Sota Arakawa, Hidekazu Tanaka, Toshihiko Kadono, Takayuki Ushikubo, Makiko Nagasawa, Hiroshi Kobayashi
Astrophysics of Galaxies
A Radio-Bright Local Little Red Dot Analog
Luis F. Rodriguez, I. FElix Mirabel, Rosa A. Gonzalez-Lopezlira et al. (+1 more)
The James Webb Space
Telescope revealed the existence in the early Universe ($z >$ 4) of large populations of little red dots (LRDs), compact red luminous sources that host rapidly growing supermassive black holes (SMBHs) surrounded by coeval
nuclear starbursts. LRDs have defining properties, one of which is the absence of
radio detections. LRDs could be
radio-undetected because of their large distances. A way to investigate the
radio properties of LRDs is to search for
radio emission in their local analogs, the Local Little Red Dot (LLRD)
galaxies at $z <$ 1 with analogous properties to LRDs. We report the
radio continuum detection of the LLRD analog J204837.26${-}$002437.2 ($z$ = 0.4332, hereinafter J2048). This adds to the previous
radio detection of two other LLRDs. However, with a flux density of 3.0$\pm$0.2 mJy at 3.0 GHz, J2048 is two orders of magnitude more
radio luminous than the previous detections. The spectral index of $\alpha$ = -0.39$\pm$0.04 is consistent with moderately optically-thick synchrotron emission. The
radio luminosity of J2048 is $1.2 \times 10^{41}~ \mathrm{erg ~s^{-1}}$, in the lower end of the range defined by
radio-loud
giant elliptical
galaxies and
quasars of $L_R$ = $10^{41-46} ~\mathrm{erg ~s^{-1}}$. The expected
radio luminosity of the SMBH associated with J2048 is estimated to be about an order of magnitude larger, suggesting that its
radio luminosity could potentially be strongly dimmed. A cosmological ($z >$ 4) LRD with
radio luminosity similar to that of J2048 would be detectable using the VLA with moderately long integrations.
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All authors Luis F. Rodriguez, I. FElix Mirabel, Rosa A. Gonzalez-Lopezlira, Laurent Loinard
Astrophysics of Galaxies
Star Formation in the H II Region Sh 2-205: 3D Morphology and Kinematics from Young Stars and Molecular Gas
Yiwei Dong, Chaojie Hao, Ye Xu et al. (+5 more)
Using
Gaia astrometry of young
stars combined with CO observations, we present the first systematic three-dimensional (3D) analysis of the structure, kinematics, and evolutionary history of the
star-forming regions in the environs of the H II region Sh 2-205 (S205). S205 exhibits a complex morphology and coherent expansion on both global and subregional scales. We identify several O9-B1
stars and a 0.56 Myr old
pulsar that are likely associated with the region. A momentum estimate suggests that feedback from these objects may account for the observed overall expansion. Trace-back analysis of the expansion, combined with color-magnitude diagram fitting for young
star clusters, indicates at least two episodes of
star formation. These results reveal a complex
star-formation history of S205 and provide new insights into its 3D
evolution.
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All authors Yiwei Dong, Chaojie Hao, Ye Xu, Yingjie Li, Zehao Lin, Dejian Liu, Yan Sun, Longhui Yang
Astrophysics of Galaxies
Catalytic formation of H_2 on carbonaceous dust grains - implications for interstellar observations
Aryav Das, Julia Gao, Daniel Vrinceanu et al. (+1 more)
We use kinetic Monte Carlo (KMC) simulations to study molecular hydrogen formation on carbonaceous
dust grain surfaces, validated against recent laboratory measurements of H$_2$ formation on coronene films at temperatures from 10 to 250 K. The model uses a three-dimensional amorphous carbon
lattice with heterogeneous physisorption ($45 \pm 5$ meV) and chemisorption ($1.75 \pm 0.25$ eV) sites, and tracks both Langmuir–Hinshelwood (LH) and Eley–Rideal (ER) formation channels within a
stochastic Gillespie event-driven framework. The model reproduces the measured efficiency curve within the experimental uncertainties, including the isothermal (constant surface temperature) measurements at 100 - 250 K. The simulations correctly describe the phase boundary between the LH and ER driven processes as functions of grain temperature and the observed crossover. Under interstellar medium conditions, 10 - 250 K and n = 10 - 10$^4$ cm$^3$, the model predicts three distinct regimes for the formation efficiency $\epsilon$, the fraction of impinging H atoms released as H$_2$. At 10 K
diffusion is slow and $\epsilon \approx 0.06$. Between 20 K and 80 K, LH dominates and $\epsilon \approx 0.28$. Above 150 K, an ER plateau at $\epsilon = 0.19$ is sustained by chemisorption-trapped H atoms. The LH-to-ER crossover occurs between 100 and 120 K. At 100 K we observe a 16% density-dependent
stochastic enhancement, which rate-equation models cannot capture. At T$_{dust}$ = 60 K, n = 10$^3$ cm$^3$ we find the ratio of H$_2$ formation to free-fall time $t_{{\rm H}_2}/t_{\rm ff} \approx 0.93$, so
dust-catalysed H$_2$ chemistry can keep pace with gravitational collapse in high-
redshift star-forming environments.
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All authors Aryav Das, Julia Gao, Daniel Vrinceanu, H. R. Sadeghpour
Astrophysics of Galaxies
The H$\alpha$ specific angular momentum of dwarf galaxies
Simon Deeley, Sarah Sweet, Dilyar Barat et al. (+3 more)
The relationship between a
galaxy's specific angular momentum $j$ and its mass $M$, parameterised by $j \propto M^\alpha$ and known as the Fall relation, has emerged as a fundamental scaling relation reflecting key physical and morphological properties of
galaxies. This relation has been well studied for
galaxies with masses above $10^{9}$ $M_{\odot}$. However, whether or not it holds for the low-mass
dwarf galaxies, especially given their varied morphologies, remains uncertain. Here we use H$\alpha$ observations of 49
star-forming
dwarf galaxies from the SH$\alpha$DE survey, as well as 20 high-mass `control'
galaxies, to investigate the
stellar $j_{*}$-$M_{*}$ relation down to masses below $10^{6}$ M$_{\odot}$. We find that the
star-forming
dwarf galaxies follow the same $j_{*}$-$M_{*}$ relation as high-mass disk-like
galaxies, with $\alpha = 0.53 \pm{0.4}$, demonstrating that the relation holds across 5 orders of magnitude in mass. We then select a matching sample from the IllustrisTNG cosmological simulation and create mock observations resembling the SH$\alpha$DE survey. We find that the simulated
dwarf galaxy population follows the extrapolated $j_{*}$-$M_{*}$ relation with a flattening and significant scatter towards lower $j_{*}$ values. Following the
evolution of these
galaxies, we find that
dwarf galaxies experience a gradual loss in $j_{*}$ with time, while high-mass
galaxies experience a sudden jump in $j_{*}$ before settling into a stable state. This dynamical
evolution leads to a
redshift dependence in $\alpha$, with $\alpha = 0.45$ at $z = 2$ and 0.55 at $z = 0$. Despite the apparent simplicity in the present-day $j_{*}$-$M_{*}$ relation over a wide mass range, the
evolution of $j$ leading to this relation is complex and dynamic.
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All authors Simon Deeley, Sarah Sweet, Dilyar Barat, Matthew Colless, Luca Cortese, Francesco D'Eugenio
Earth and Planetary Astrophysics
Stability Mapping of the New Uranian Moon S/2025 U1 with Updated Masses for Cordelia, Ophelia, and Cressida
J. Xavier, A. Amarante, S. Giuliatti Winter et al. (+1 more)
We investigate the dynamics of Uranus's inner satellite system considering three recent updates: the inclusion of the new moon S/2025~U1, revised mass estimates for Cordelia, Ophelia, and Cressida, and updated zonal harmonic coefficients (J$_2$, J$_4$, and J$_6$). Using numerical integrations, mean-motion resonance analysis, and Frequency Map Analysis (FMA), we explore their impact on orbital stability. For the first time, we analyze the dynamics of the newly discovered moon S/2025~U1 and find that it follows a stable orbit, exhibiting smooth variations in its orbital elements over 250,000~years. Depending on the adopted radius, the gravitational influence of S/2025~U1 on the surrounding region is more compatible with a body of approximately 5-7 km radius, producing
diffusion maps associated with a regular orbital
evolution. Furthermore, the case $R = 7$ km shows a reduction in the
diffusion of neighboring satellites, suggesting a possible local stabilizing effect on the system's orbital
evolution. We also identified inner and outer regions of low
diffusion around its orbit, suggesting that the dynamical environment is compatible with survival of coorbital particles or additional small satellites. In contrast, very high radius values, particularly $R = 20$ km, tend to increase
diffusion among neighboring satellites, making this scenario less compatible with a dynamically stable orbital configuration. We further explore the survival of hypothetical satellites near S/2025~U1. Our results show that bodies with masses up to $3\times$ that of S/2025~U1 can remain stable in both the interior (between S/2025~U1 and Ophelia) and the exterior (between S/2025~U1 and Bianca) of its orbit. Finally, Cressida, Desdemona, Juliet, and Portia are most sensitive to updated parameters. Most resonances circulate, while Belinda-Perdita 44:43 confines the system with reduced libration amplitude.
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All authors J. Xavier, A. Amarante, S. Giuliatti Winter, A. Ferreira
Astrophysics of Galaxies
Gaia DR3 Limits on Stellar Engine Technosignatures in Nearby Stars
Bo-Lun Huang, Zhen-Zhao Tao, Tong-Jie Zhang et al. (+1 more)
An operating
stellar engine that transfers momentum to its host
star could produce an approximately persistent transverse acceleration during the
Gaia Data Release 3 (DR3) observing epoch. We search for such accelerations among 406,984 quality-selected
Gaia DR3
stars with nominal distances below 200 pc (about 650 light-years), using 8,890 published Acceleration7 solutions. Because long-period binaries and astrometric systematics can produce similar sky-plane
curvature, we model these conventional explanations together with a broad component that can absorb any remaining persistent acceleration or model mismatch. At $a_0 = 2.60 \times 10^{-4}$ m s$^{-2}$, where essentially the entire parent sample is searchable, mapping the residual weights evaluated at the one-sided 95% profile-limit point gives a parent-population fraction limit of $1.21 \times 10^{-5}$. Multiplying this fraction by the parent-sample size gives a summed upper-limit weight of about five
star-equivalents above the threshold. Toward the lowest acceleration thresholds, the searchable fraction declines rapidly, so the corresponding bounds primarily describe the reach of the search. No individual source is interpreted as a technological signal.
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All authors Bo-Lun Huang, Zhen-Zhao Tao, Tong-Jie Zhang, Zhi-E Liu
High Energy Astrophysical Phenomena
SN 2023gfo: A Peculiar Type IIP Supernova with High Luminosity and Normal Plateau Duration
Riko Namba, Masayuki Yamanaka, Keiichi Maeda et al. (+9 more)
We present near-infrared (NIR) and optical observations of the highly reddened Type IIP
supernova (SN) 2023gfo in the nearby
galaxy NGC 4995 ($d = 26.4 \pm 3.2$ Mpc), which reached a high peak luminosity of $M_V = -18.6$ mag. The SN was initially detected as a faint red event, with $B-V = 0.8$ mag at the beginning of the plateau phase. By comparison with template, we estimate a total extinction of $A_V = 2.1$ mag. After correcting for this extinction, we derive a peak quasi-bolometric luminosity of $(5.9 \pm 1.5)\times10^{42}$ erg s$^{-1}$, placing this event among the most luminous SNe IIP, while its plateau duration remains within the normal range. The early-phase optical spectrum exhibits a P-Cygni profile of H$\alpha$, with a broad absorption of $V$ = $13{,}800$ km s$^{-1}$, which is among the highest observed for SNe IIP at comparable epochs. The high luminosity and the normal plateau duration suggest that this event represents an outlier. Applying an analytical model, we infer an unusually large progenitor radius. This may indicate that the progenitor experienced an extreme energy injection from the core to the envelope shortly before explosion, resulting in a substantially inflated radius. While ejecta-circumstellar matter (CSM) interaction could in principle account for the high luminosity, we find no observational evidence supporting strong interaction.
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All authors Riko Namba, Masayuki Yamanaka, Keiichi Maeda, Avinash Singh, Kenta Taguchi, Takahiro Nagayama, Miho Kawabata, Koji S. Kawabata, Tatsuya Nakaoka, Devendra Sahu, Anjasha Gangopadhyay, G. C. Anupama
Astrophysics of Galaxies
The Koi Pond: A Strongly Lensed Protocluster Core hosting a Diverse Population of DSFGs
Nicholas Foo, Kevin C. Harrington, Brenda L. Frye et al. (+29 more)
We present James Webb Space
Telescope (JWST) and Atacama Large Millimeter Array (ALMA) observations of PJ0846+15, The Koi Pond, a strongly lensed protocluster core at
Cosmic Noon. This field offers a magnified view of 11 dusty
star-forming
galaxies (DSFGs) all at $z=2.67$ (within $\Delta V=800$ km s$^{-1}$) spanning a projected extent of $>300$ kpc lensed by a $z=0.77$ foreground cluster. NIRCam and ALMA Band 6 continuum measurements map the
stellar distribution and thermal
dust emission respectively at a spatial resolution of $\sim$0.15$^{\prime\prime}$. This analysis reveals a diverse population of DSFGs, with evidence of both interacting and non-interacting systems exhibiting a wide range of morphological features including spiral arms, bars, bulges, clumps/
stellar clusters,
tidal tails/debris and displaced molecular gas reservoirs. Comparing the rest-frame J- band continuum (F444W) vs (i-J) color (F277W$-$F444W), we find a wide range of values, suggesting a $>$1-dex spread in
stellar mass and a
dust attenuation reddening of $\Delta A_{\mathrm{V}} > 1$ mag. The DSFG members exhibit varying
dust sizes relative to the
stellar emission, ranging from compact dusty cores to
galaxy-wide emission. Resolved color maps of individual sources showing a spread as high as F277W$-$F444W$=2$ mag suggesting complex
stellar-to-
dust geometry. Although gas-rich mergers are identified in the core, the most red and
dust emitting members are disks exhibiting clumpy structure indicating secular growth can drive these starburst events. Such a remarkable range in properties within this sample suggest DSFGs in protocluster core environments follow diverse evolutionary pathways towards their transition into quiescent, elliptical cluster
galaxies.
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All authors Nicholas Foo, Kevin C. Harrington, Brenda L. Frye, Patrick S. Kamieneski, Melanie Kaasinen, Rafael Ortiz III, Alex Pigarelli, Gibson B. Bowling, Belén Alcalde Pampliega, Joe Bhangal, Timothy Carleton, Jianhang Chen, Seth H. Cohen, Camila de Sá-Freitas, Jose Diego, Román Fernández Aranda, Carlos Garcia Diaz, Nikhil Garuda, Eric F. Jiménez-Andrade, Daizhong Liu, James D. Lowenthal, Allison Man, Allison Noble, Massimo Pascale, Francesca Rizzo, Hannah R. Stacey, Amit Vishwas, Q. Daniel Wang, Rogier A. Windhorst, Ilsang Yoon, Min S. Yun, Dazhi Zhou