Solar and Stellar Astrophysics
Solar neutron and muon detection on November 11, 2025: First simultaneous recovery of energy spectra
A.Chilingarian, B.Sargsyan, L.Kozliner et al. (+1 more)
Ground Level Enhancement (GLE) events provide rare opportunities to study high-energy
solar particle acceleration through direct detection of secondary radiation at ground level. On November 11, 2025, the Aragats
Solar Neutron Telescope (ASNT) recorded a statistically significant increase in high-energy
neutron and
muon fluxes associated with an X5.1
flare and the subsequent
Solar Energetic
Proton (SEP) event. The event displayed a unique dual-peak profile: an initial hard component at 10 28 UT, followed by a softer yet still energetic peak at 10 45 UT. For the first time, we report simultaneous energy spectra of atmospheric
neutrons and
muons measured in the 10 600 MeV range at Aragats. Broken-power-law fits reveal a clear temporal
evolution of acceleration conditions, evidenced by spectral indices declining with energy. These findings highlight the unique capabilities of the ASNT as an instrument for studying extreme
solar particle acceleration.
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All authors A.Chilingarian, B.Sargsyan, L.Kozliner, T.Karapetyan
Cosmology and Nongalactic Astrophysics · Cross-listed from physics.ins-det
Quenching factors for Na recoils as a function of Tl dopant concentrations in NaI(Tl) crystals
G. Angloher, M. R. Bharadwaj, A. Böhmer et al. (+51 more)
Thallium-doped sodium iodide (NaI(Tl)) scintillation detectors play an important role in the field of direct dark matter (DM) searches. The DAMA/LIBRA experiment stands out for its reported observation of an annually modulating DM-like signal, which is in direct contrast with other results. To accurately calibrate the energies of
nuclear recoil signals with electron
recoils, precise measurements of the quenching factor of the NaI(Tl)
crystals are essential, as the two processes have different scintillation light yield. In this article, we present results of a systematic study carried out by the COSINUS collaboration and Duke University to measure the quenching factor of sodium (Na)
recoils as a function of
nuclear recoil energy and for differing Thallium (Tl) dopant concentrations in the bulk
crystal. Five ultrapure NaI(Tl)
crystals, manufactured by the Shanghai Institute for Ceramics, were irradiated with a quasi-monoenergetic
neutron beam at the Triangle Universities
Nuclear Laboratory, North Carolina, USA. The quenching factor for low
nuclear recoil energies of 5-26keV$_{nr}$ was extracted for all 5
crystals. A Tl-dependence could be deduced with a proportional response calibration schema using a $^{241}$Am source. However, this effect was not observed when using a low-energy calibration line from $^{133}$Ba.
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All authors G. Angloher, M. R. Bharadwaj, A. Böhmer, M. Cababie, I. Colantoni, I. Dafinei, N. Di Marco, C. Dittmar, L. Einfalt, F. Ferrella, F. Ferroni, S. Fichtinger, A. Filipponi, T. Frank, M. Friedl, M. Gapp, L. Gai, Z. Ge, M. Heikinheimo, M. N. Hughes, K. Huitu, M. Kellermann, R. Maji, M. Mancuso, L. Pagnanini, F. Petricca, S. Pirro, F. Pröbst, G. Profeta, A. Puiu, F. Reindl, K. Schäffner, J. Schieck, P. Schreiner, C. Schwertner, K. Shera, M. Stahlberg, A. Stendahl, M. Stukel, C. Tresca, F. Wagner, S. Yue, V. Zema, Y. Zhu, P.S. Barbeau, S.C. Hedges, C. Awe, J. Runge, T. Johnson, D.M. Markoff, P. An, C. G. Prior, A. Bracho, S. Alawabdeh
Solar and Stellar Astrophysics · Cross-listed from physics.space-ph
On the Relation between Source Region and In-situ Variability of Low $\delta B$ Solar Wind Streams
Kai Jaffarove, Tamar Ervin and Stuart D. Bale
Parker
Solar Probe (PSP) observed a high speed stream near the Sun ($\sim 9.8 R_\odot$) in March 2025. As this stream was observed near the Sun, it allowed for an unparalleled opportunity to observe pristine, coronal hole wind with little
evolution (expansion, stream interaction, etc) effects impacting its properties. Through an ensemble of
magnetic connectivity analysis utilizing Potential Field Source Surface (PFSS) modeling and ballistic propagation, we make estimates of the footpoints, and corresponding source region parameters, associated with the stream. We then look at how the low variability regions (small gradient in the in-situ $B_r$) are related to the variability in the field strength at their source ($B_0$). We find that about half of these periods are associated with low source region variability. Lastly, we examine the low $\delta B / B$ periods between switchback patches and similarly find that they show statistically less variability in their associated $B_0$ value than their switchback patch counterparts. We believe that these results point to a
solar source of these “low-variability" periods, that warrants further investigation with composition diagnostics and more complex modeling techniques.
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Earth and Planetary Astrophysics
Vibrationally excited H2 mutes the He i triplet line at 1.08 {\mu}m on warm exo-Neptunes
Antonio García Muñoz, Dario De Fazio, David J. Wilson et al. (+1 more)
Context. Neptune-sized
exoplanets or exo-Neptunes are fundamental in the description of
exoplanet diversity. Their
evolution is sculpted by atmospheric escape, often traced by absorption in the H i Lyman-{\alpha} line at 1,216 Å and the He i triplet line at 1.08 {\mu}m. On warm exo-Neptunes HAT-P-11 b, GJ 3470 b and GJ 436 b, H i Lyman-{\alpha} absorption causes extreme in-transit obscuration of their host
stars. This suggests that He i triplet line absorption will also be strong, yet it has only been identified on two of these
planets. Aims. We explore previously unaccounted for processes that might attenuate the He i triplet line on warm exo-Neptunes. In particular, we assess the role of vibrationally excited H2 to remove the He+ ion that acts as precursor of the absorbing He(2$^3$S ). Methods. We formed thermal rate coefficients for this chemical process, leveraging the available theoretical and experimental data. The process becomes notably fast at the temperatures expected in the atmospheric layers probed by the He i triplet line. Results. Our simulations show that the proposed process severely mutes the line on GJ 3470 b and causes the nondetection on GJ 436 b. The overall efficiency of this mechanism is connected to where in the atmosphere the H2-to-H transition occurs and, ultimately, to the amount of high-energy radiation received by the
planet. The process will be more significant on small
exoplanets than on hotter or more massive ones, as for the latter the H2-to-H transition generally occurs deeper in the atmosphere. Conclusions. Weak He i triplet line absorption need not imply the lack of a
primordial, H2-He-dominated atmosphere, an idea to bear in mind when interpreting the observations of other small
exoplanets.
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All authors Antonio García Muñoz, Dario De Fazio, David J. Wilson, Kevin France
Cosmology and Nongalactic Astrophysics
The Atacama Cosmology Telescope: $B$-mode delensing with DR6 data and external tracers of large-scale structure
Emilie Hertig, Antón Baleato Lizancos, Frank J. Qu et al. (+14 more)
Large-scale $B$-mode polarization of the
cosmic microwave background (CMB) is a
prime target for current and future experiments in search of
primordial gravitational waves (PGW). With increasingly sensitive instruments being deployed, secondary $B$-modes induced by the weak gravitational
lensing of CMB
photons are becoming an important limitation and need to be removed, a process known as delensing. In this work, we combine internally reconstructed CMB
lensing maps from the Atacama Cosmology
Telescope (ACT) DR6 with
galaxy samples from unWISE and a map of the
cosmic infrared background (CIB) fluctuations from Planck to produce a well-correlated tracer of the CMB
lensing field. Our co-added tracer, shown to be 55-85% correlated with the true
lensing convergence at multipoles $L \leq 2000$, is then convolved with ACT DR6 $E$-mode polarization to yield a template of the
lensing $B$-modes. We assess its performance on a wide range of scales by using it to delens ACT DR6 and Planck $B$-modes over 23% of the sky, removing around 39% of the
lensing power at $100\leq l \leq 1500$ and 47% at $30 \leq l \leq 300$, respectively. Our template achieves the highest delensing efficiency to date and will be useful for the analysis of early polarization maps from the Simons Observatory (SO). We finally outline prospects for further improvements by including additional large-scale structure tracers from upcoming cosmological surveys.
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All authors Emilie Hertig, Antón Baleato Lizancos, Frank J. Qu, J. Richard Bond, Erminia Calabrese, Anthony Challinor, Mark J. Devlin, Jo Dunkley, Thibaut Louis, Mathew S. Madhavacheril, Toshiya Namikawa, Lyman A. Page, Neelima Sehgal, Blake Sherwin, Cristóbal Sifón, Suzanne T. Staggs, Edward J. Wollack
Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc
Searches for Post-Merger Gravitational Waves with CoCoA: Sensitivity Projections Across Large Template Banks for Current and Next-Generation Detectors
Tanazza Khanam, Alessandra Corsi, Robert Coyne et al. (+1 more)
The multi-messenger detection of the binary
neutron star (NS) merger GW170817 has revolutionized the field of gravitational wave (GW) astronomy. However, several important questions remain to be answered. One of these is the nature of the compact remnant leftover by GW170817 (short- or long-lived NS versus black hole). A key goal going forward is to understand the diversity of NS-NS merger remnants, and how such diversity maps onto their viability as gamma-ray burst (GRB) central engines. Here, we present a study aimed at assessing the sensitivity of triggered searches for intermediate-duration, post-merger GWs powered by long-lived GRB remnants using networks of current and future ground-based GW detectors and the Cross-Correlation
Algorithm (CoCoA). We develop a Python-based framework to efficiently estimate CoCoA distance horizons for a broad range of post merger secular bar-mode waveforms and for different GW detector networks. This framework can be used to identify the most promising regions of parameter space in which to concentrate search efforts, helping design future search strategies to optimally balance search sensitivity and related parameter space gridding schema against computational cost.
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All authors Tanazza Khanam, Alessandra Corsi, Robert Coyne, Michael St. Pierre
High Energy Astrophysical Phenomena
Data span and frequency coverage requirements for robust detection and inference in PTAs: A case study with EPTA DR2
Irene Ferranti, Mikel Falxa, Federico Fantoccoli et al. (+2 more)
Pulsar Timing Arrays (PTAs) are approaching the sensitivity required for a $5\sigma$ detection of the nanohertz
stochastic gravitational-wave background (GWB). This makes it crucial to deeply understand the behaviour of our analysis pipelines. A counterintuitive feature of the European
Pulsar Timing Array (EPTA) second data release is that restricting the
dataset to the last 10.3 years (DR2new) increases the inferred GWB significance from $\leq2\sigma$ for the full 25-year
dataset (DR2full) to $\geq3.5\sigma$. We investigate whether this behaviour indicates an anomaly or is a possible outcome of the pipeline. Using realistic, DR2-like simulations with varying timespans, we find that the first 10 years contribute little to the GWB evidence due to their limited frequency coverage. This produces substantial overlap between the HD S/N distributions of DR2full and DR2new. Random noise fluctuations therefore yield a higher GWB evidence in DR2new than in DR2full in $15\%$ of cases. Furthermore, $5\%$ of simulations match the HD S/N of the real data, indicating that the observed behaviour is consistent with being a $\sim2\sigma$ outcome due to noise fluctuations. Regardless of significance, DR2new simulations introduce biases in the GWB parameter estimation due to spectral leakage effects that are ignored in standard analyses and which flatten the inferred spectrum. Including leakage removes these biases, demonstrating the reliability of DR2new when the signal is properly modelled. Furthermore, we demonstrate that combining EPTA DR2full with long-baseline data from NANOGrav and PPTA, as well as low-frequency data from LOFAR and NenuFAR, significantly enhances GWB evidence and parameter accuracy. Finally, we examine the impact of the observation timespan and find that short-baseline
datasets introduce strong amplitude biases and are ineffective at constraining the GWB.
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All authors Irene Ferranti, Mikel Falxa, Federico Fantoccoli, Alberto Sesana, Golam Mohiuddin Shaifullah
Astrophysics of Galaxies
The relations between dust properties and galaxy global / integrated quantities in the nearby Universe
Bogdan A. Pastrav
Results of a case study of a sample of low-
redshift galaxies are presented, to determine
dust temperatures and emissivity indices through a less time-consuming method, and to connect both global and integrated
galaxy properties with those of
dust, ISM and
star-formation.
Dust temperatures ($T_{d}$) are determined based on the corresponding
galaxy dust masses, independently calculated in our previous work, through a self-consistent method, without the need to actually perform a complete spectral energy distribution (SED) fit of the cold
dust emission fluxes. The range and average
dust temperatures are found to be consistent within errors with values from other studies. Simultaneously, the
dust emissivity indices ($\beta_{d}$) are determined, and their
evolution with temperature quantified, with the $T_{d}$ anti-correlation still being present. It is investigated whether $\beta_{d}$ can be predicted from other relation or if it scales with other integrated
dust / ISM or
galaxy property, which could be used as a proxy. In this respect, new and established relations between $T_{d}$, $\beta_{d}$, the
dust surface density and global / integrated
galaxy and
star-formation related quantities are presented and analysed. We find that SFR, sSFR or $\Sigma_{SFR}$ are inconclusive traces of the
dust temperature. We also find that the extent of
dust emission distribution is slightly lower on average, but comparable with the optical
stellar continuum emission one. The results and conclusions can be relevant for larger scales studies of low to mid-
redshift galaxies from the latest surveys.
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Cosmology and Nongalactic Astrophysics
Modeling Galaxy Formation in Cosmological Simulations with CRK-HACC
Nicholas Frontiere, J.D. Emberson, Michael Buehlmann et al. (+4 more)
Self-consistently modeling baryonic effects in survey-scale cosmological simulations has become increasingly important as the diversity, precision, and statistical reach of modern observations continue to improve. The advent of exascale computing now enables a new generation of simulations that couple these physical processes across full-sky volumes with excellent statistical sampling of large-scale structure tracers such as
galaxies, groups, and clusters. To support these efforts, we extend the CRK-HACC framework, a GPU-accelerated cosmological hydrodynamics code, with a suite of astrophysical subgrid models that simulate radiative cooling,
star formation,
stellar evolution, and AGN feedback within a numerically robust formulation optimized for scalability on modern exascale architectures. The models were selected and calibrated to reproduce observed
galaxy stellar mass functions over the
redshift range $0 < z < 2$ and cluster populations probed by cosmological surveys, capturing the large-scale baryonic
evolution relevant for multi-wavelength, cross-correlated analyses. We describe the implementation and calibration of these models and demonstrate their consistency with observed
galaxy population statistics and modern hydrodynamic simulations, establishing the baseline for exascale efforts that extend this framework to survey-scale volumes.
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All authors Nicholas Frontiere, J.D. Emberson, Michael Buehlmann, Salman Habib, Katrin Heitmann, Nesar Ramachandra, Claude-André Faucher-Giguère
High Energy Astrophysical Phenomena · Cross-listed from gr-qc
Gravitational waves from the late inspiral, transition, and plunge of small-mass-ratio eccentric binaries
Devin R. Becker, Scott A. Hughes and Gaurav Khanna
Black hole binaries with small mass ratios will be important sources for the forthcoming
Laser Interferometer Space
Antenna (LISA) mission. Models of such binaries also serve as useful tools for understanding the dynamics of compact binary systems and the gravitational waves they emit. Using an eccentric Ori-Thorne procedure developed in previous work, we build worldlines that describe the full inspiral and plunge of a small body on an initially eccentric orbit of a Kerr black hole. We now calculate the gravitational waves associated with these trajectories using a code that solves the Teukolsky equation in the time domain. The final cycles of these waveforms, the ringdown, contain a superposition of Kerr quasinormal modes followed by a power-law tail. In this paper, we study how a binary's eccentricity and orbital anomaly angle affect the excitation of both quasinormal modes and late-time tails. We find that the relative excitation of quasinormal modes varies in an important and interesting way with these parameters. For some anomaly angles, the relative excitations of quasinormal modes are essentially indistinguishable from those excited in quasi-circular coalescences. Consistent with other recent studies, we find that eccentricity tends to amplify the late-time power-law tail, though the amount of this amplification varies significantly with orbital anomaly. We thus find that eccentricity has an important impact on the late-time coalescence waveform, but the interplay of eccentricity and orbit anomaly complicates this impact.
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High Energy Astrophysical Phenomena
Gravitational Waves as a Probe of Core Collapse Supernova Progenitor Structure
R. Daniel Murphy, Elle Brinkman, Colter J. Richardson et al. (+5 more)
We present the gravitational wave predictions from two-dimensional core collapse
supernova (CCSN) simulations initiated from two nearly identical progenitors that have significantly different internal structures due to their late-stage
stellar evolution. At the time of collapse, the 15.78 $M_{\odot}$ and 15.79 $M_{\odot}$ progenitors have compactness parameters $\xi_{2.5}$ of 0.136 and 0.206, respectively. We connect several features of the gravitational wave signal from each model to its previously explored explosion dynamics. In particular, the greater
accretion onto the PNS of the more compact model is evident in broad-band frequency features with larger amplitude gravitational wave strains and greater gravitational wave energy release when compared to the less compact model. Additionally, the faster contraction rate of the more compact model is reflected in the $\sim$26% greater slope of the $g$-/$f$-mode feature (gfF)
evolution of the gravitational wave signal. This work shows that in principle gravitational wave detection may provide information about interior
stellar structure.
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All authors R. Daniel Murphy, Elle Brinkman, Colter J. Richardson, Evan Semenak, Anthony Mezzacappa, Pedro Marronetti, Eric J. Lentz, Stephen W. Bruenn
Instrumentation and Methods for Astrophysics · Cross-listed from physics.plasm-ph
GANDALF: A hardware-agnostic spectral solver for kinetic reduced MHD turbulence
Anjor Kanekar
We present GANDALF, a JAX-based spectral solver for Kinetic Reduced MHD (KRMHD)
turbulence designed to lower infrastructure barriers to
plasma turbulence research. Existing production codes require specialized HPC infrastructure and compilation expertise, limiting participation to well-resourced institutions. GANDALF addresses this barrier by leveraging JAX's hardware abstraction to run transparently on laptops, desktop GPUs, and Apple Silicon without modification, enabling single-command installation via pip. We employ
Fourier spectral methods for spatial discretization and Hermite spectral basis for velocity space, combined with an exponential integrating factor method that exactly propagates linear Alfvén waves, eliminating associated numerical stiffness. Verification demonstrates research-grade accuracy: linear Alfvén waves achieve machine precision (~10^{-15} relative error), the Orszag-Tang
vortex conserves energy to 10^{-6} over two Alfvén times, and driven
turbulence reproduces the expected k_perp^{-5/3} cascade spectrum. GANDALF enables rapid prototyping, parameter surveys, and educational applications on commodity hardware. The code complements rather than replaces established solvers like AstroGK and Viriato, prioritizing accessibility for researchers without HPC resources. By removing infrastructure barriers while maintaining spectral accuracy, GANDALF broadens participation in fundamental
plasma turbulence research, particularly benefiting students, small research groups, and institutions in developing regions.
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Cosmology and Nongalactic Astrophysics
Intrinsic galaxy alignments in CAMELS simulations and the significant impact of baryon model
Daniel Bilsborrow and Niall Jeffrey
We present a detection of the intrinsic
galaxy alignments in the CAMELS suite of hydrodynamic simulations. We find that the
alignment amplitude depends significantly on cosmological and
supernova feedback parameters - specifically $\Omega_m$, $\sigma_8$, $A_{\text{SN1}}$, $A_{\text{SN2}}$- while no dependence on AGN feedback is observed (due to the limited simulation volume $(25\,h^{-1}\,\text{Mpc})^3$). The dependence on $\sigma_8$ vanishes when projected correlation functions $w_{m+}$ are normalized by matter density correlations $w_{mm}$, consistent with predictions from linear
alignment models. We find
alignment amplitudes in quiescent
galaxies to exceed those in
star-forming
galaxies by an order of magnitude. Moreover, examining orientation-only correlation functions from ellipticity-normalized
galaxies $\tilde w_{m+}$, we confirm that
alignment signals retain sensitivity to
supernova feedback across full,
star forming, quiescent, and ellipticity-normalized samples. Finally, we find evidence that
supernova feedback impacts
alignment signals differently in
star-forming versus quiescent populations, suggesting that distinct
alignment mechanisms operate across
galaxy types. Our results offer key insights for understanding
galaxy formation and
alignment models for future weak gravitational
lensing analyses.
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Solar and Stellar Astrophysics
Evaluating Star-Planet Interactions with Zeeman Doppler Imaging: Case Study in YZ Ceti
J. Sebastian Pineda, Stefano Bellotti, Jackie Villadsen et al. (+3 more)
The recent detections of
radio emission from the nearby
exoplanet host, YZ Ceti, suggest that the
star is possibly interacting with its rocky innermost
planet. These
radio emissions are characterized by strong circular polarization, and appear to repeat within consistent orbital phase windows dictated by the orbital position of YZ Ceti b. If confirmed, this interaction would provide a first means to concretely assess the
magnetic field of a close-in rocky
exoplanet. This kind of
magnetic star-
planet interaction (SPI) should depend on both the exoplanetary orbit, and the geometry of the
stellar magnetic field. In this article, we report measurements of the large-scale
magnetic field
topology of the
star YZ Ceti for the first time, and interpret the cumulative
radio data sets in that context to evaluate the plausibility of
magnetic SPIs. We find evidence both against and in support of the SPI hypothesis, but crucially that the measured
magnetic field does not rule out SPI scenarios. However, clear evaluation of these possibilities requires more accurate assessments of the
magnetic field
evolution across time. We additionally suggest that YZ Ceti may be exhibiting
planet-induced flaring potentially triggered by
exoplanet crossings of the Alfvén surface as the
planet orbit approaches the
stellar magnetic equator, and YZ Ceti b experiences dramatic shifts in the ambient field, its polarity, and connectivity to the host
star.
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All authors J. Sebastian Pineda, Stefano Bellotti, Jackie Villadsen, Aline Vidotto, Julien Morin, Colin P. Folsom
Astrophysics of Galaxies
The LMT 2 millimeter receiver system (B4R). II. Science demonstration observations toward Orion-KL/OMC-1
Teppei Yonetsu, Ryohei Kawabe, Yuki Yoshimura et al. (+26 more)
We present the results of mapping and single-point spectral scans toward Orion-KL/OMC-1 performed as science demonstrations of a 2 mm SIS receiver, the Band 4 Receiver (B4R), installed on the 50 m Large Millimeter
Telescope (LMT). To prove the capabilities of mapping and spectral scans with the B4R on the LMT, commissioning observations were conducted employing the on-the-fly mapping technique toward Orion-KL/OMC-1, which covers a map size of 5$'\times$5$'$. These mapping observations were performed with two frequency settings providing 10 GHz in total (131.4-133.9 GHz and 145.1-147.6 GHz; 136.2-138.7 GHz and 149.9-152.4 GHz) with a frequency resolution of 76.293 kHz. We conducted spectral line identification analysis for the hot core and compact ridge regions in the Orion-KL with a beam size of 11-12$''$. We detected nearly 400 emission lines and identified two recombination lines and 29 molecular species, including isotopologues, deuterated molecules, and vibrational excited states, despite the short integration time. These results are consistent with those of previous studies. The 29 molecular species include nitrogen (N)-bearing complex organic molecules (COMs) and oxygen (O)-bearing COMs. To demonstrate the capability of the B4R in astrochemistry, we conducted detailed analyses of column densities, rotational temperatures, and relative abundances with respect to H$_2$ on two representative COMs, N-bearing C$_2$H$_5$CN and O-bearing CH$_3$OCHO in the central 40$''\times$40$''$ area of the map. The wide bandwidth of 10 GHz enabled the use of 8 and 34 emission lines, respectively. The spatial differences in the physical and chemical properties between these molecules were derived at a spatial resolution of $\sim$12$''$. The B4R on the LMT was successfully demonstrated to be powerful for mapping and spectral scans and to have high potential for the study of interstellar chemistry.
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All authors Teppei Yonetsu, Ryohei Kawabe, Yuki Yoshimura, Kotomi Taniguchi, Yoshito Shimajiri, Omar Sergio Rojas-García, Arturo I. Gómez-Ruiz, Takeshi Sakai, Kunihiko Tanaka, Bunyo Hatsukade, Akio Taniguchi, Yoichi Tamura, Tatsuya Takekoshi, Tai Oshima, Kotaro Kohno, Masato Hagimoto, David H. Hughes, Peter F. Schloerb, David Sánchez-Argüelles, Kamal Souccar, Gopal Narayanan, Min S. Yun, Víctor Gómez-Rivera, Iván Rodríguez-Montoya, Edgar Colín-Beltrán, Miguel Chávez Dagostino, Javier Zaragoza-Cardiel, Shinji Fujita, Hiroyuki Maezawa
Astrophysics of Galaxies · Cross-listed from hep-ph
High Mass Dark Matter Searches With the High Speed Flux From the Large Magellanic Cloud
Nassim Bozorgnia, Joseph Bramante and Andrew Buchanan
As the hunt for dark matter progresses, recently there have been advances in the search for heavy dark matter with a mass well above a TeV. We show the importance of properly modeling the local dark matter velocity distribution, beyond the standard Maxwellian
halo model, and in particular how the dynamics of the Large Magellanic Cloud and Milky Way may impact heavy dark matter searches. We introduce some new computational techniques for accurately computing the dark matter flux and the associated detector response. As a specific example, we examine the effect of the Large Magellanic Cloud on heavy dark matter bounds obtained from experiments searching for
cosmic rays and
magnetic monopoles using plastic etch detectors at the Ohya Mine and aboard the Skylab Space Station.
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Earth and Planetary Astrophysics
The HITRAN2024 methane update
T. Bertin, I. E. Gordon, R. J. Hargreaves et al. (+22 more)
Spectroscopic parameters of methane from many different studies were gathered to improve the HITRAN database towards its 2024 version. After a validation process using high-resolution FTS and CRDS spectra, about 80,000 lines of the four most abundant isotopologues were replaced from the dyad to the triacontad regions. These changes amount to 51,000 transition wavenumbers, 18,000 line intensities, 33,000 pressure-broadening half-widths, and 3300 assignments. 44,000 new lines were added with 16,000 old lines removed, extending the database from 12,000 cm$^{-1}$ up to 14,000 cm$^{-1}$, and covering some gaps. A greater focus was brought on the pentad, octad, and tetradecad regions, targeted by several remote sensing instruments. In these regions, comparisons of spectral fits from multiple line lists were performed, taking only the parameters that provide best fit for each line. In the $\nu _3$ band, in addition to replacing the previous values, speed-independent pressure broadening parameters of $^{12}$CH$_4$ were gathered and used to fit Padé-approximant functions. These functions then replaced any outdated experimental data in $\nu _3$, missing data in the new lines, as well as the values that were determined to be outside their physical boundaries. The CH$_3$D broadening parameters were replaced in the same manner, for missing and low or high values, using a semi-empirical formula instead.
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All authors T. Bertin, I. E. Gordon, R. J. Hargreaves, J. Tennyson, S. N. Yurchenko, K. Kefala, V. Boudon, C. Richard, A. V. Nikitin, V. G. Tyuterev, M. Rey, M. Birk, G. Wagner, K. Sung, B. P. Coy, W. Broussard, G. C. Toon, A. A. Rodina, E. Starikova, A. Campargue, Z. D. Reed, J. T. Hodges, Y. Tan, N. A. Malarich, G. B. Rieker
Cosmology and Nongalactic Astrophysics · Cross-listed from hep-ph
Bubble Nucleation from Boson Star Collapse
Aleksandr Azatov, Takeshi Kobayashi and Nicklas Ramberg
We present a new classical mechanism for nucleation of bubbles of true
vacuum. The mechanism arises when dense
boson stars form in the false
vacuum. As the
boson stars collapse due to attractive self-interactions, the field inside the
star cores is enhanced beyond the potential barrier. Subsequently the
stars explode as true
vacuum bubbles, and induce a cosmological phase transition. The mechanism raises the possibility that a
vacuum that is stable against
quantum tunneling can be vulnerable to “astrophysical” processes.
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Astrophysics of Galaxies
LYRA ultra-faints: The emergence of faint dwarf galaxies in the presence of an early Lyman-Werner background
Shaun T. Brown, Azadeh Fattahi, Thales A. Gutcke et al. (+6 more)
We present a suite of zoom-in cosmological hydrodynamical simulations of
dwarf galaxies using the LYRA
galaxy formation model with an extremely high mass resolution of $4\, \mathrm{M_{\odot}}$, evolved to $z=0$. The suite contains 65
haloes selected from Local Group like environments, spanning $M_{\mathrm{200c}}=10^7$ to $5\times10^9\, \mathrm{M_{\odot}}$. The sample includes small ultra-faints with $M_\ast\sim100\, \mathrm{M_{\odot}}$ through to classical
dwarfs with $M_\ast \sim 5\times10^6 \mathrm{M_{\odot}}$, as well as
haloes that remain dark to the present day. We explore two prescriptions for the high-
redshift ($z>7$) Lyman-Werner background (LWB), differing in intensity and
redshift evolution.
Star formation begins early ($z\gtrsim8$) in progenitors with $M_{\mathrm{200c}}\sim10^5$-$10^6 \mathrm{M_{\odot}}$, where molecular hydrogen enables warm moderate-density gas to efficiently cool. The LWB strongly influences the $z=0$
halo occupation fraction, shifting the dark-to-luminous transition from $M_{\mathrm{200c}}\sim10^7 \mathrm{M_{\odot}}$ (weaker LWB) to $M_{\mathrm{200c}}\sim10^8 \mathrm{M_{\odot}}$ (stronger LWB).
Galaxies with $M_\ast\gtrsim10^5 \mathrm{M_{\odot}}$ are mostly insensitive to the LWB choice, whereas lower mass systems respond strongly, producing markedly different
stellar mass-
halo mass (SMHM) relations. The weaker LWB yields a very shallow SMHM slope with nearly constant scatter, while the stronger LWB introduces a pronounced break at $M_{\mathrm{200c}}\sim10^9 \mathrm{M_{\odot}}$, where
haloes of similar mass host
galaxies with $M_\ast\sim10^3$ to $10^5 \mathrm{M_{\odot}}$ or remain dark. Both models produce a minimum
stellar mass floor at $M_\ast\sim10^3 \mathrm{M_{\odot}}$, originating from
galaxies that undergo a single burst of
star formation at high
redshift before self-quenching from their first
supernovae.
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All authors Shaun T. Brown, Azadeh Fattahi, Thales A. Gutcke, Sylvia Ploeckinger, Joaquin Sureda, Sownak Bose, Jessica E. Doppel, Rüdiger Pakmor, Adrian Jenkins
Astrophysics of Galaxies
Probing Exotic Astrophysical Dark objects through Astrometric Microlensing from Gaia
Lalit Singh Bhandari, Vikram Rentala, Arun M. Thalapillil et al. (+1 more)
We present the first comprehensive study of astrometric microlensing by exotic astrophysical dark objects, focusing on two theoretically motivated models – Q-ball and
boson star. We demonstrate that these extended objects generate distinctive signatures that depart markedly from point-mass lenses like
primordial black holes. The smoking-gun signature for these exotic objects is the emergence of caustics, which form when the lens radius is below a critical threshold. Crossing these caustics induces discontinuous jumps in the images-centroid trajectory, a distinctive feature of these extended dark objects. We show these patterns are sensitive to the internal mass profile, with
boson stars generating larger, more prominent caustic structures than Q-balls – enabling the models to be distinguished. Using the
Gaia DR3
stellar catalogue, we forecast a high-yield discovery potential, up to $\sim 6000$ detectable astrometric microlensing events for a 10-year mission, peaking for $M \sim 1-10~M_\odot$ and $R \lesssim 10~\text{AU}$. In the absence of anomalous detections,
Gaia can set powerful 90% confidence level constraints on the fractional abundance of these exotic objects, reaching $f_{\mathrm{DM}} \le 10^{-3}$ in the peak region which covers masses from $10^{-1}-10^{7}~M_{\odot}$ and radii $R<10^{6}~\text{AU}$. Crucially, these projected astrometric microlensing constraints are significantly stronger than existing photometric microlensing limits in the $1-10~M_\odot$ mass range. This work establishes astrometric microlensing with
Gaia as a powerful, complementary, and near-future probe with the potential to discover exotic astrophysical dark objects.
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All authors Lalit Singh Bhandari, Vikram Rentala, Arun M. Thalapillil, Himanshu Verma
Astrophysics of Galaxies
J-PAS: A value-added catalogue of optical line intensities for nebular emission galaxies (JOLINES)
J.A. Fernández-Ontiveros, C. López-Sanjuan, A. Hernán-Caballero et al. (+38 more)
We present the value-added catalogue JOLINES (J-PAS optical line intensities for nebular emission
galaxies), which provides emission-line fluxes in
galaxies at from the spectrophotometric catalogues of miniJPAS, J-NEP and the J-PAS early data release (EDR). This catalogue will be updated with future data releases, offering a growing resource for the study of emission-line
galaxies. To obtain reliable emission-line fluxes from narrow-band photometry, we employed spectral energy distribution (SED) fitting using CIGALE, a robust tool that reconstructs the continuum emission and ensures accurate flux measurements. This method effectively mitigates uncertainties associated with direct continuum subtraction techniques, and systematics such as absorption components in the emission lines. We validate our approach using simulated observations of
galaxy spectra with added noise, testing the method's performance across different equivalent width (EW) regimes and emission-line strengths. Additionally, we compare the recovered emission-line fluxes with spectroscopic measurements from the Sloan Digital Sky Survey (SDSS) and the Dark Energy Spectroscopic Instrument (DESI). Our results show a tight correlation between photometric and spectroscopic fluxes, particularly for bright emission lines, with a typical dispersion of $\sim$0.3 dex. Reliable fluxes are obtained for emission lines with EW $\gtrsim20\, \rm{\mathring{A}}$, in agreement with previous empirical studies. The current catalogue comprises approximately 13,900 sources with reliable flux measurements in the H$\alpha$+[NII] complex and 7,200 in [OIII]$\lambda 5007$, ensuring statistically robust samples for the brightest optical emission lines. This resource will be expanded in future J-PAS releases, facilitating large-scale studies of
star formation, AGN activity, and
galaxy evolution.
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All authors J.A. Fernández-Ontiveros, C. López-Sanjuan, A. Hernán-Caballero, A. Lumbreras-Calle, J. Iglesias-Páramo, A. Torralba, R.M. González Delgado, A. del Pino, P.T. Rahna, I.E. López, R. Amorín, J.M. Vílchez, C. Kehrig, I. Breda, D. Fernández Gil, F.D. Arizo-Borillo, A. Giménez-Alcázar, E. Pérez-Montero, F.J. Sáez Ruiz, N. Acharya, R. Abramo, J. Alcaniz, N. Benítez, S. Bonoli, S. Carneiro, J. Cenarro, D. Cristóbal-Hornillos, S. Daflon, R. Dupke, A. Ederoclite, C. Hernández-Monteagudo, J. Liu, A. Marín-Franch, C. Mendes de Oliveira, M. Moles, F. Roig, L. Sodré Jr., K. Taylor, J. Varela, H. Vázquez Ramió, J. Zaragoza-Cardiel
Astrophysics of Galaxies
Little Red Dots host Black Hole Stars: A unified family of gas-reddened AGN revealed by JWST/NIRSpec spectroscopy
Anna de Graaff, Raphael E. Hviding, Rohan P. Naidu et al. (+34 more)
We use the DAWN JWST Archive to construct and characterise a sample of 146 little red dots (LRDs) across 2.0<z<9.3, selecting all sources with v-shaped UV-optical continua from NIRSpec/PRISM spectra and compact morphologies in NIRCam/F444W imaging. We show that LRD continuum spectra are ubiquitously well described by modified blackbodies across ~$0.4-1.0\mu$m, with typical T~5000K or $\lambda_{peak}$~$0.65\mu$m across 2 dex in luminosity, and a tail toward T~2000K. LRDs therefore trace a locus in the Hertzsprung-Russell diagram that is directly analogous to
stars on the Hayashi track, strongly supporting the picture that LRDs are AGN embedded in optically-thick dense gas envelopes. Hotter LRDs with $\lambda_{peak}<0.65\mu$m typically have strong Balmer breaks, redder UV slopes and high optical luminosities; other LRDs show weak or no Balmer breaks, and wide variety in $\beta_{UV}$ and $L_{5100}$. Crucially, we demonstrate that the UV-optical continuum shapes and luminosities are strongly linked to the $H\alpha,\ H\beta$, [OIII] and OI line properties. There is a tight linear relation between the H$\alpha$ and optical continuum luminosities, as well as H$\alpha$ and OI$_{8446}$, indicating that Balmer, OI and optical emission must primarily be powered by the same source. The Balmer decrement increases strongly toward higher $L_{H\alpha}$, $L_{5100}$ and Balmer break strength, providing key evidence for luminosity-dependent effects of collisional (de-)excitation and resonant scattering in the gaseous envelopes. In contrast, we show that [OIII] emission likely originates from
star-forming host
galaxies, and that its strong correlation with Balmer break strength arises naturally from variation in the AGN-to-host ratio among the LRD population. Our work presents an empirical description of the nature and structure of LRDs, defining a new
benchmark for ongoing LRD model developments.
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All authors Anna de Graaff, Raphael E. Hviding, Rohan P. Naidu, Jenny E. Greene, Tim B. Miller, Joel Leja, Jorryt Matthee, Gabriel Brammer, Harley Katz, Rachel Bezanson, Leindert A. Boogaard, Sownak Bose, John Chisholm, Nikko J. Cleri, Pratika Dayal, Robert Feldmann, Yoshinobu Fudamoto, Seiji Fujimoto, Lukas J. Furtak, Karl Glazebrook, Rashmi Gottumukkala, Kasper E. Heintz, Vasily Kokorev, Ivo Labbe, Michael V. Maseda, Ian McConachie, Themiya Nanayakkara, Erica Nelson, Przemysław Nowaczyk, Pascal A. Oesch, Hans-Walter Rix, David J. Setton, Alberto Torralba, Fabian Walter, Bingjie Wang, Andrea Weibel, Arjen van der Wel
High Energy Astrophysical Phenomena
The impact of magnetic fields during tidal disruption events
Simona Pacuraru, Clément Bonnerot and Martin E. Pessah
During a
tidal disruption event (TDE) the stream debris inherits the
magnetic field of the
star. As the stream stretches, the
magnetic field evolves and can eventually become dynamically important. We study this effect by means of magnetohydrodynamic simulations and a semi-analytic model of the disruption of a main-sequence
star by a supermassive black hole. For
stellar magnetic fields stronger than $\sim 10^4\,\rm{G}$,
magnetic pressure becomes important in a significant fraction of the mass of the stream, leading to a fast increase in its thickness, an effect that may impact its subsequent
evolution. We find that this dynamical effect is associated with a phase of transverse
equilibrium between
magnetic and
tidal forces, which causes the stream width to increase with distance to the black hole as $H \propto R^{5/4}$. In the unbound tail, this fast expansion could enhance the
radio emission produced by the interaction with the ambient medium, while in the returning stream, it may qualitatively affect the subsequent gas
evolution, particularly the gas dynamics and radiative properties of shocks occurring after the stream's return to pericentre. By characterizing the magnetohydrodynamic properties of the stream from disruption to the first return to pericentre, this work provides physically motivated initial conditions for future studies of the later phases of TDEs, accounting for
magnetic fields. This will ultimately shed light on the role of
magnetic fields in enabling angular momentum transport in the ensuing
accretion disk, thereby affecting observable signatures such as X-ray radiation and relativistic
outflows.
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Earth and Planetary Astrophysics
A Paradigm Shift in Exoplanet False Positive Identification with HIP-44302
Arielle C. Frommer, Jason D. Eastman, David R. Ciardi et al. (+5 more)
Through detailed modeling of all three
stars, we show that HIP-44302 is a false positive triple-
star system. While the Transiting
Exoplanet Survey Satellite initially designated the object as a planetary candidate, observing a 10-day transit and secondary eclipse in Sectors 8 and 35, we definitively exclude this scenario, finding instead that the transit comes from eclipsing
stellar companions with $P = 9.599214$ days and $a = 0.1415$ AU. This binary orbits a single
star at a wide separation of $\rho = 0.2946''$, determined through high-resolution AO and speckle imaging and corresponding to a $\sim$297 AU, $\sim$1886-year orbit at a distance of 1010 pc. Using transit data and photometry, we use EXOFASTv2 to fit the transit light curve, spectral energy distribution, and MIST evolutionary models of the three
stars. We find that the isolated
star and the larger binary
star are massive A
stars, with the single
star having evolved off the main sequence, while the smaller companion is a G
star. We also found an unusually low rotational velocity of 2.3 km/s from the single A
star, observed from MINERVA and TRES RVs, implying a pole-on orientation. The triple-
star architecture derived from multiple data sources made this target a complex system that required new capabilities within EXOFASTv2 to properly model. Our successful modeling demonstrates a new paradigm for false positive identification and classification that incorporates imaging, photometry, transits, and global modeling to definitively rule out false positives that may otherwise pollute candidate catalogs without extensive follow-up observations.
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All authors Arielle C. Frommer, Jason D. Eastman, David R. Ciardi, Steve B. Howell, George Zhou, Allyson Bieryla, Carl Ziegler, Kepler Owen
Instrumentation and Methods for Astrophysics
The LMT 2 Millimeter Receiver System (B4R). I. Overview and Results of Science Demonstration
Ryohei Kawabe, Takeshi Sakai, Kunihiko Tanaka et al. (+30 more)
We report on the results of the on-sky test and science demonstration conducted with the 2 mm receiver system, B4R, on the 50 m Large Millimeter
Telescope (LMT), located at an altitude of 4600 m in Mexico. The B4R receiver was developed based on the dual-polarization sideband-separating mixer technology of the Atacama Large Millimeter/submillimeter Array, and is equipped with a fast
Fourier transform digital spectrometer, XFFTS. The primary science objective is the spectroscopic
redshift identification of high-
redshift dusty
star-forming
galaxies, complementing the existing 3 mm
Redshift Search Receiver by enabling the detection of multiple carbon monoxide lines. Additionally, the B4R receiver broadens the range of science cases possible with the LMT, including astrochemistry, as the 2 mm band encompasses unique molecular lines such as deuterated molecules and shock tracers. During on-site commissioning in 2018 and 2019, we successfully demonstrated on-the-fly mapping and position-switching observations toward the Orion Molecular Cloud 1 and bright high-
redshift dusty
star-forming
galaxies, respectively. We confirmed that the installed B4R system largely met its basic performance specifications. Furthermore, we measured the LMT's aperture efficiencies across the entire B4R frequency range (130-160 GHz), finding them to be roughly consistent with expectations based on a surface accuracy of 100 $\mu$m and the receiver optics design. These results with the B4R will enable the most sensitive single-dish spectroscopic observations at 2 mm using the LMT.
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All authors Ryohei Kawabe, Takeshi Sakai, Kunihiko Tanaka, Akio Taniguchi, Bunyo Hatsukade, Yoichi Tamura, Yuki Yoshimura, Tatsuya Takekoshi, Tai Oshima, Masato Hagimoto, Teppei Yonetsu, Kotomi Taniguchi, Kotaro Kohno, Hiroyuki Maezawa, David H. Hughes, Peter F. Schloerb, Edgar Colín-Beltrán, Miguel Chávez Dagostino, Víctor Gómez-Rivera, Arturo I. Gómez-Ruiz, Gopal Narayanan, Iván Rodríguez-Montoya, David Sánchez-Argüelles, Yoshito Shimajiri, Kamal Souccar, Min S. Yun, Tom J. L. C. Bakx, Kevin C. Harrington, Shinji Fujita, Fumitaka Nakamura, O. S. Rojas-García, Alfredo A. Montaña Barbano, Javier Zaragoza-Cardiel
Astrophysics of Galaxies
Statistical Properties of Cold Streams In Massive Star-Forming Halos in TNG50
Isabel Medlock, Daisuke Nagai, Nir Mandelker et al. (+4 more)
Cold, dense streams of gas are predicted to penetrate deeply into massive
halos (> 10^12 Msun) at
cosmic noon (z=4-2), fueling
galaxies to sustain high
star formation rates. We investigate the prevalence of such cold streams in TNG50 over the range z=4-0, using a novel
algorithm to automatically detect cold streams in simulated
halos. We qualitatively and quantitatively characterize the
geometric and physical properties of the detected streams over
cosmic time. We find that cold streams are ubiquitous in massive
halos at
cosmic noon, occurring in more than 80 percent of such systems down to z=1, before becoming rare by z=0. At their peak prevalence (z=2-1), streams are often found in roughly co-planar, three-stream configurations. These streams generally exhibit a dense and cool core, surrounded by a diffuse and warmer envelope. However, we find that in TNG50, these streams typically disrupt in the outer
halo and do not penetrate efficiently to the central
galaxy, with the total mass inflow from streams peaking at z=2. Our results underscore the importance of cold streams in fueling
galaxies at early times, but they highlight the need for higher-resolution simulations to fully capture their survival and impact at later epochs. Future cosmological zoom-in simulations, with better resolution in the CGM, will be essential to resolve turbulent mixing layers and feedback-inflow interactions that determine whether cold streams can reach the
galactic disk.
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All authors Isabel Medlock, Daisuke Nagai, Nir Mandelker, Volker Springel, Frank C. van den Bosch, Elad Zinger, Barry T. Chiang
Astrophysics of Galaxies
APEX survey of interstellar HCl: $^{35}$Cl/$^{37}$Cl isotopic ratios in dense cores and outflows
Lennart M. Böhm, Arshia M. Jacob, Friedrich Wyrowski et al. (+3 more)
Despite being only the 19th most abundant element in the interstellar medium, chlorine's reactivity and
volatility give rise to a unique interstellar chemistry, favouring the formation of several chlorine-bearing hydrides. Further, the $^{35}\text{Cl}/ ^{37}$Cl ratio probes nucleosynthesis across the
Galaxy. Yet, studies of Cl-bearing molecules have remained limited to a few sightlines due to observational challenges. We systematically investigated the
Galactic distribution of HCl and the [H$^{35}$Cl]/[H$^{37}$Cl] ratio in high-mass
star-forming regions. As a probe of a region's nucleosynthesis history, this ratio may constrain predictions of
Galactic chemical
evolution models. We observed the ground-state $J=1$$-$0 lines of H$^{35}$Cl and H$^{37}$Cl toward 28 high-mass
star-forming regions with SEPIA660 on APEX, more than doubling the number of known HCl detections and revealing with XCLASS models emission from both cores and
outflows. H$^{35}$Cl was detected in all sources, H$^{37}$Cl in all but two, with spectral line profiles ranging from those with only emission to complex emission-absorption mixtures. We find column densities of the order of $10^{13}\,\mathrm{cm}^{-2}$ for H$^{35}$Cl and isotopic ratios between $1.6$ and $3.5$ in emission-only sources. The derived [H$^{35}$Cl]/[H$^{37}$Cl] aligns with
Galactic chemical
evolution models and shows no trend with Galactocentric radius. However, local variations may reflect recent nucleosynthesis. Overall, the results suggest that most
Galactic chlorine was synthesized during epochs of lower average
metallicity in the
Galaxy. Notably, we detect H$^{35}$Cl emission arising from
outflows - particularly explosive ones - hinting at its presence in a broader range of environments. The present single-dish observations cannot reveal the origin of HCl in
outflows; necessitating interferometric follow-up observations.
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All authors Lennart M. Böhm, Arshia M. Jacob, Friedrich Wyrowski, Karl M. Menten, Katharina Immer, Ashley T. Barnes