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Research Trends

Latest preprints in space engineering and astrophysics.

astro-ph.GA

Does IRS13 require an intermediate-mass black hole?

Václav Pavlík, Vladimír Karas, Florian Peißker, Bhavana Bhat, Andreas Eckart

We investigate whether the Galactic-centre association IRS13 requires an intermediate-mass black hole (IMBH) to remain bound. Using high-precision $N$-body calculations of IRS13-like systems orbiting the Milky Way supermassive black hole (SMBH), as well as simulations of more massive infalling clusters, we find that an IRS13-sized cluster dissolves on a very short timescale even when an IMBH of $4\times10^4\,M_\odot$ is present. The observed velocity dispersion can arise naturally from the tidal…

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astro-ph.COastro-ph.IMhep-exhep-phphysics.ins-det

Reconstructing Dark Matter Mass and Discriminating Standard and Non-Standard WIMP-Nucleus Interactions with Paleo-Detectors

Dionysios P. Theodosopoulos, Katherine Freese, Chris Kelso, Patrick Stengel

Paleo-detectors record and retain crystal damage in ancient minerals from nuclear recoils induced by dark matter scattering over geological timescales. Previous studies have shown that paleo-detectors can provide sensitivity to a variety of dark matter (DM) scenarios which is complementary to conventional direct-detection experiments. In this paper, we complete the first detailed study of how well paleo-detectors can reconstruct DM parameters or distinguish between different types of DM interact…

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astro-ph.HEgr-qc

3D Binary Neutron Star Merger Ejecta Evolution up to Seconds Timescale: Dynamics, Element Distribution, and Light Curves

Luis Felipe Longo Micchi, Fabio Magistrelli, Maximilian Jacobi, Sebastiano Bernuzzi

We present long-term, three-dimensional simulations of ejecta from four binary neutron star mergers to second-long time-scales. Numerical-relativity data serve as boundary conditions for a general-relativistic hydrodynamics evolution incorporating an equation of state valid outside nuclear statistical equilibrium and an effective nuclear-heating prescription based on reaction-network calculations. We investigate the ejecta's dynamical and geometrical properties, the impact of nuclear heating, th…

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astro-ph.GA

From Cluster Core to Splashback: Linking Dynamical Structure to Multidimensional Galaxy Evolution in the Coma Cluster

Mohamed H. Abdullah, S. W. El-Sogheir, Gillian Wilson, Magdy Y. Amin, A. Ahmed

We investigate galaxy evolution across the full dynamical structure of the Coma cluster using the GalWCat19 spectroscopic cluster catalog combined with SDSS-based value-added galaxy properties. We measure a splashback radius of $R_{sp} = 2.94 \pm 0.16~h^{-1}\, Mpc$. Using specific star formation rate (sSFR), color offset from the red sequence ($Δ(g-r)_{RS}$), and bulge-to-total ratio ($B/T$) as independent diagnostics, we find a coherent environmental transition from quiescent, red, bulge-domina…

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astro-ph.GA

Spiral Morphology and Radial Migration: Kinematically heating, cooling, and cold

Kathryne J. Daniel, M. E. Wisz, Karen L. Masters, Rosemary F. G. Wyse, Amy Smock, Lipika Chatur

Transient spiral arms are known to drive radial redistribution of stars and thus could play a central role in shaping disk galaxies, including modifying, over time, the age, chemical, and kinematic (chrono-chemo-dynamic) distributions in the Milky Way. However, the physical factors governing the efficiency of such processes remain poorly understood. This paper investigates how the morphology of spiral arms -- the number, pitch angle, lifetime, and radial dependence of the pattern speed -- influe…

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astro-ph.EPastro-ph.GAastro-ph.SR

SMA Observations Reveal Abundant HNC Chemistry in Transition Disks

Kyle Gresko, Charles J. Law, Deryl E. Long, L. Ilsedore Cleeves, Feng Long, Yuri Aikawa, Jennifer B. Bergner, Romane Le Gal et al.

The physical and chemical conditions of protoplanetary disks shape the properties of nascent planetary systems. The line ratios and relative abundances of the HCN-HNC isomer pair are well-suited for tracing these gas conditions, since isomer chemistry is linked to the underlying temperature, elemental abundances, and irradiation environment of the emitting gas. While HCN emits bright lines regularly observed in disks, the fainter HNC lines are targeted significantly less often, precluding our ab…

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astro-ph.EPastro-ph.IM

Technology and Science Advancing Observations with Roman Coronagraph Informed by Ground-Based High-Contrast Imaging

Mona El Morsy, Thayne Currie, Brianna Lacy, Danielle Bovie, Erica Dykes, Jie Li, Olivier Guyon, Julien Lozi et al.

The Roman Coronagraph technology demonstration focuses on achieving $<$ 10$^{-7}$ contrasts within the instrument's dark hole and our ability to detect and characterize properties of faint companions around bright stars. Here, we describe results from a study of potential Roman Coronagraph technology demonstration phase observations focused on these goals, informed by the ongoing OASIS survey at the Subaru Telescope and precursor survey work. OASIS provides at least three compelling targets for…

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astro-ph.GA

An X-ray Absorption-Line Survey of the Circumgalactic Medium of M31 with XMM-Newton

Kaile Wang, Zheng Zhou, Taotao Fang, Fabrizio Nicastro

X-ray absorption line spectroscopy provides a powerful method for probing the extended hot circumgalactic medium (CGM) of individual galaxies. In this study, we present the first survey of \osv and \oeit absorption lines toward the hot halo of M\,31, using $15$ and $18$ background active galactic nuclei, with impact parameters ranging from $R_{\rm imp}\sim300$--$730$~kpc and $\sim190$--$730$~kpc, respectively. We find a marginal excess absorption above the expected Milky Way (MW) foreground towa…

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hep-phastro-ph.HEhep-ex

A $U(1)_{(B-L)_3}$ model for dark matter and the $B^+\to K^+ν\barν$ excess reported by Belle II

MohammadAli Abri, Yasaman Farzan

We explore the $U(1)_{(B-L)_3}$ gauge symmetry under which only third generation fermions are charged. The cancelation of the $[U(1)_{(B-L)_3}]^3$ anomaly requires a chiral fermion, $χ_L$, singlet under the gauge group but charged under $U(1)_{(B-L)_3}$. This chiral fermion can play the role of thermal dark matter with a relic abundance set via the freeze-out scenario through the annihilation to pairs of the third generation fermions. In the quark mass basis, the new gauge boson will have off-di…

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quant-phastro-ph.IM

Eliminating photon transport in long-baseline optical interferometry using quantum memories

Yousef K. Chahine, Chaohan Cui, William DeRocco, Daniel Gottesman, Saikat Guha, Emil T. Khabiboulline, Zhenning Liu, Brittany McClinton et al.

In this paper, we describe the fundamental operating mechanisms of optical interferometry using quantum memory and entanglement. We show how these remove the optical delay line bottleneck. Quantum memory is not without its own set of challenges, some of which include very small bandwidths as well as limitations in storage time. We examine the influence of timing artifacts on memory photon capture probability and interferometric complex visibility. We highlight keystone areas of technology that r…

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astro-ph.SRastro-ph.GA

Filling the Gap: Calibrating Gyrochronology at 1.3 Gyr with the Benchmark Cluster NGC-752

Andrew W. Boyle, Andrew W. Mann

Empirical gyrochronology relies on co-eval stellar associations to map stellar rotation as a function of mass and age. The accuracy of its age predictions is therefore limited by the number and quality of benchmark rotation sequences. The well-characterized clusters NGC-6811 (t ~ 1 Gyr) and NGC-6819 (t ~ 2.5 Gyr) bracket an intermediate-age interval in which stellar spin-down remains poorly constrained due to lack of available rotation data. At t ~ 1.3 Gyr, NGC-752 provides a critical benchmark…

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astro-ph.GAastro-ph.COgr-qc

Flat Galactic Rotation Curves Interpreted as Evidence for the Mach's Principle

Andres Escala

We explore the possibility of a Machian interpretation for the phenomena associated with asymptotically flat rotation curves in disk galaxies, providing an alternative to both the Lambda-Cold Dark Matter ($Λ$CDM) paradigm and MOdified Newtonian Dynamics (MOND). We argue that the MOND acceleration scale $a_0$ is likely not a new fundamental constant, but rather a manifestation of the cosmological scales of the observable Universe ($a_0 \sim c^2/R_u \sim c^4/GM_u \sim c/t_u$). We rewrite the Baryo…

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astro-ph.GA

Discovery of four Narrow-line Type-1 Quasars at z = 2.54 -- 6.06 with Subaru 'Onohi'ula PFS-SSP

Ayumi Takahashi, Yoshiki Matsuoka, Yoshiki Toba, Tohru Nagao, Toshihiro Kawaguchi, Hiroaki Sameshima, Alberto Rodríguez-Ardila, Andy D. Goulding et al.

We report the discovery of four narrow-line type-1 quasars (NLQ1s) from the Subaru 'Onohi'ula Prime Focus Spectrograph Subaru Strategic Program (PFS-SSP). To extend a comprehensive understanding of this population to the distant universe, we searched for broad-line AGNs (quasars) whose rest-UV spectral shapes resemble those of local NLS1 galaxies, utilizing the Ly$α$ line profile. We identified four NLQ1s, including one candidate, at $z=2.54$ -- $6.06$. The obtained spectra show a prominent Ly$α…

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astro-ph.IMphysics.soc-ph

Which is the best day of the week to submit to arXiv:astro-ph?

Chirag Sharma, Shantanu Desai

We examine whether the citations received by refereed astronomy papers vary systematically with the day of the week of their arXiv preprint release. We use NASA ADS citation data for all refereed articles published in 2020--2023 in six journals (MNRAS, ApJ, ApJL, ApJS, A\&A and JCAP; 37,173 papers with astro-ph primary preprints), combined with version-1 submission timestamps from the arXiv API. We group papers both by submission weekday and by the day their announcement batch appears on arXiv,…

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astro-ph.GA

A cosmic collision in the making: JWST/NIRISS reveals a merging and maturing protocluster core at z~3 around a red quasar

C. Bertemes, D. Wylezalek, G. Noirot, R. Hviding, D. S. N. Rupke, N. L. Zakamska, S. Veilleux, L. Gatto et al.

We report the discovery of ``The Step'', a dense protocluster at z=3 revealed by JWST/NIRISS Wide-Field Slitless Spectroscopy (WFSS) of the field around the luminous quasar and starburst SDSSJ165202.64+172852.3. The protocluster contains at least 18 member galaxies and exhibits two substructures in the 3D position-velocity space - notably a distinctive step-like distribution, from which the nickname derives. We propose that the Step may be undergoing a merger of two haloes, which could also expl…

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astro-ph.GA

Unveiling and Characterising Ubiquitous Nitrogen Enhancement in $6 \leq z \leq 10$ Galaxies with JWST Spectroscopy

Raunaq Singh Rai, Guido Roberts-Borsani

The James Webb Space Telescope (JWST) has revealed a growing number of $z>6$ galaxies with enhanced N/O ratios that challenge standard chemical enrichment frameworks. We test whether this is exclusive to extreme systems or a generic feature of $6 \leq z \leq 10$ populations through a stacking analysis of 135 galaxies with JWST/NIRSpec $R\sim1000$ spectroscopy, probing the origin of N, C and O enrichment and its dependence on recent star formation. A full-sample composite reveals prominent C III]…

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astro-ph.HE

Radiative Transfer Modeling of Stripped-envelope Supernovae II: Neural Network Emulation of Light Curves

S. Karthik Yadavalli, V. Ashley Villar, Maria R. Drout, Sebastian Gomez, Miranda Pikus, Yunyi Shen

We present the first neural-network emulator of stripped-envelope supernova (SESN) lightcurves, trained on a grid of 4499 light curves simulated with the radiative transfer (RT) code sedona. Using this emulator, we show that m_ni, m_ejecta, the ejecta velocity profile, and the degree of Ni-56 mixing can all be inferred from multiband lightcurves. We find that the degeneracy between ejecta mass and ejecta velocity is substantially weaker with this emulator than in traditional semianalytical model…

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astro-ph.HEastro-ph.GA

Decoding the jet of BL Lacertae using relativistic magneto-hydrodynamics

G. F. Paraschos, J. A. Kramer, I. Liodakis, S. G. Jorstad, A. P. Marscher, I. Myserlis, I. Agudo

Blazars are a highly variable subclass of active galactic nuclei, whose relativistic jet is pointed towards our line of sight at a small angle. Their variability is often characterised by multi-band flares. BL Lacertae (BL Lac), the namesake of a blazar subclass recently exhibited the highest recorded linearly polarised optical flare. We investigate the origin of this flare via very-long-baseline interferometry observations. Our analysis shows that the sweeping, helical motion of the BL Lac jet,…

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astro-ph.EPastro-ph.SR

A Sulfur-Rich Atmosphere for the Young Jupiter Analog AF Lep b Reveals Significant Solid Accretion

Jerry W. Xuan, William O. Balmer, Yayaati Chachan, Jean-Baptiste Ruffio, Kazumasa Ohno, Robert J. De Rosa, Aneesh Baburaj, Eric L. Nielsen et al.

AF Lep b is one of the closest analogs to Jupiter in terms of mass ($3-4~M_{\rm{Jup}}$) and semi-major axis ($9$ AU) amenable to spectroscopic characterization. We present JWST/NIRSpec high-contrast spectroscopy of the planet from $2.85-5.3~μ$m at $R\sim3000$, which provide detections of CO$_2$, H$_2$S, CH$_4$, $^{12}$CO (and $^{13}$CO), and H$_2$O, as well as complementary JWST/NIRCam imaging that captures the planet's continuum flux from $4.0-4.7~μ$m. Combining the JWST observations with spect…

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astro-ph.HE

Explaining the X-ray Precursor, Ultra-long Prompt Emission, and Week-long Decay of GRB250702B with a Jetted Micro-TDE

Fulya Kıroğlu, Taeho Ryu, Alexander Tchekhovskoy, Kyle Kremer, Daichi Tsuna, Brian D. Metzger

The longest detected gamma-ray burst, GRB250702B, exhibited seven hours of prompt $γ$-ray emission, preceded by a soft X-ray precursor ($\sim1$ day earlier) and followed by a weeks-long fading X-ray tail. Lacking an established progenitor for all three phases, we propose that this ultra-long GRB (ULGRB) is powered by a jetted micro-tidal disruption event (micro-TDE), in which a spinning stellar-mass black hole (BH) disrupts a Sun-like star and launches a relativistic jet via the Blandford-Znajek…

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hep-phastro-ph.COastro-ph.EPphysics.ao-ph

Mysterious Transients in the Palomar Observatory Sky Survey (POSS-1) as profound manifestation of the Dark Matter physics

Ariel Zhitnitsky

Transient star-like objects of unknown origin have been identified in the first Palomar Observatory Sky Survey (POSS-1) as part of the Vanishing and Appearing Sources during a Century of Observations (VASCO) project. The source of the transients recorded by POSS-1 remains unknown, which is the warrant to coin the observed phenomena as Mysterious Transients (MT). We advocate an idea that the dark matter (DM) in form of the axion quark nuggets (AQN) made of standard model quarks (or antiquarks) an…

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astro-ph.COastro-ph.GAastro-ph.HEgr-qc

Realization Variance of Gravitational Wave Background Anisotropies from Shot Noise for Pulsar Timing Arrays

Meng-Xiang Lin, Adam Lidz, Chung-Pei Ma

Shot-noise anisotropies in the nHz gravitational wave background (GWB) are a promising target for pulsar timing arrays (PTAs). If the nHz GWB is sourced by merging supermassive black hole binaries (SMBHBs), as current evidence suggests, the shot-noise signal is expected to be large, potentially of order unity at observing frequencies of $f \sim 1 \, \mathrm{yr}^{-1}$. In this regime, the signal is dominated by rare bright binaries, and Poisson fluctuations in the discrete SMBHB population produc…

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astro-ph.SRastro-ph.EPastro-ph.GA

IPA: Morphology and Kinematics of Molecular Hydrogen Winds in Five Young Protostars across the Mass Spectrum Observed with JWST

Himanshu Tyagi, P. Manoj, Mayank Narang, S. Thomas Megeath, Robert Gutermuth, Lee Hartmann, Alessio Caratti o Garatti, Dan M. Watson et al.

Molecular winds may play a key role in governing angular momentum transport and accretion during the early evolution of protostars. We present the morphology and kinematic properties of the H$_2$ emission in five young, envelope-dominated, protostars across a broad bolometric luminosity range, from 0.2 to $10^4~L_{\odot}$, observed with the NIRSpec/IFU and MIRI/MRS onboard JWST as part of the Investigating Protostellar Accretion (IPA) program. A rich set of pure rotational lines of H$_2$, up to…

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astro-ph.SRastro-ph.EP

Nascent Embedded-protostar Survey in Taurus (NEST) II: Measuring Dust Mass, Disk Size, and Gas Mass

Noshin Yesmin, Patrick Sheehan, John Tobin, Aislinn Coleman-Plante, Nicholas P. Ballering, Tyler L. Bourke, Josh Eisner, Hauyu Baobab Liu et al.

Envelope-embedded protostellar disks represent the earliest stage of protoplanetary disk evolution, but their masses and sizes are difficult to measure because disk emission is entangled with the envelope. We analyze 26 protostellar disk systems in Taurus using ALMA Band 7 (345 GHz; ~0.3'') and VLA Ka-band (33 GHz; ~0.2'') continuum observations, together with molecular-line data to constrain disk gas masses. At 345 GHz, the median flux density, dust mass, and radius are 71 mJy, 5.5 M_Mearth, an…

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astro-ph.HEastro-ph.SR

Peak 'Nebular' Emission and Early Flux Excesses in Ca-strong Supernovae

C. -G. Touchard-Paxton, K. Maguire, C. Frohmaier, W. V. Jacobson-Galán, M. Pursiainen, C. Angus, J. Sollerman, A. Polin et al.

Calcium-strong supernovae (Ca-strong SNe) are a class of thermonuclear transient characterised by rapid photometric evolution (rise times of <= 16 d) and nebular-phase spectra dominated by strong [Ca II]7291,7324 emission, in comparison to the strength of [O I]6300,6364 emission. Despite their distinctive spectra and association with remote environments, their origins remain uncertain. Using new discoveries from surveys such as the Zwicky Transient Facility, supplemented by archival data, we com…

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astro-ph.SRcond-mat.mtrl-sci

Infrared Spectroscopy and Photochemistry of Aromatic Nitriles in Para-Hydrogen Matrices

Sam McGrath, Vincent J. Esposito, Linshan Zeng, Thomas H. Speak, Brendan Moore, Pavle Djuricanin, Jun Miyazaki, Takamasa Momose et al.

Motivated by recent detections of several aromatic nitriles in Taurus Molecular Cloud-1, we report laboratory and theoretical investigations of the vibrational spectroscopy and photochemistry of singly and doubly cyano-substituted benzene in solid para-hydrogen matrices. We compare the photochemistry of cyanobenzene (benzonitrile) and three dicyanobenzene isomers initiated by excitations at 193 nm. In addition, we report the photochemistry of deuterated cyanobenzene (d$_5$-cyanobenzene), enablin…

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astro-ph.IM

A bestiary of low-level electrical artifacts in SPHEREx flight data

Candice M. Fazar, Michael Zemcov, C. Darren Dowell, Brendan P. Crill, Chi Nguyen, Howard Hui

SPHEREx, NASA's all-sky spectrophotometric survey mission, maps the sky in 102 spectral channels from 0.75 um to 5.0 um at 6.15'' resolution from low-Earth orbit using a custom readout of six HAWAII-2RG detectors. The SPHEREx instrument team and Science Data Center have built a robust science data pipeline that includes mitigating image-space artifacts arising from low-level optical and electronic effects. Analysis of first-survey flight data has confirmed predictions for some of these effects,…

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astro-ph.HE

The Galactic Neutrino Sky: Predictions from Gamma-ray Source Populations

Leo Seen, Ke Fang

High-energy neutrino emission from the Galactic plane has been detected at a significance of $5.7σ$, with a prominent excess toward the inner Galaxy. We show that this excess can be naturally explained by the spatial distribution of Galactic neutrino sources. By combining $γ$-ray source catalogs spanning GeV-PeV energies and selecting candidate hadronic emitters, we construct ReGal-$γ$, a template of resolved Galactic $γ$-ray sources that may also produce high-energy neutrinos. Compared with mod…

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astro-ph.IMastro-ph.HE

NASA ASTRA Initiative White Paper: Space-Based Mission for Ultrahigh Energy Particles

Mauricio Bustamante, Johannes Eser, Ke Fang, Claire Guépin, John Krizmanic, Eric Mayotte, Keith McBride, Kohta Murase et al.

Ultra-high-energy cosmic rays ($E_{\rm CR} \gtrsim 1$ EeV) are the highest-energy particles known, signaling extreme particle processes at work in the universe. However, many aspects of their nature remain largely unknown, even after more than a century of study. Very-high-energy ($E_ν\gtrsim 1$ PeV neutrinos associated with cosmic-ray interactions, both during the acceleration process and propagation, would provide new insight into these extreme particles, as we have seen at lower energies with…

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astro-ph.GA

An emerging baryon cycle in a galaxy 500 million years after the Big Bang

Shengzhe Wang, Xin Wang, Hang Zhou, Zhijie Qu, Zhaozhou Li, Yuxuan Pang, Qianqiao Zhou, Shouyi Wang et al.

The emergence of stellar feedback as a regulator of galaxy growth marks a fundamental transition in cosmic history. At early times, rapid gas accretion and collapse may induce intense star formation before feedback becomes effective, producing feedback-free starbursts. When and how such bursts subsequently develop into self-regulated baryon cycles remain observationally unknown. Here we show that Gz9p3, a merging galaxy at $z=9.311$, is caught in this transition only 500 million years after the…

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