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Research Trends

Latest preprints in space engineering and astrophysics.

astro-ph.GA

Reionization driven by the few: the ionizing budget of galaxies at z=5-10 from JWST/NIRSpec

Emma Giovinazzo, Pascal A. Oesch, Anne Verhamme, Romain A. Meyer, Callum Witten, John Chisholm, Rui Marques-Chaves, Charlotte Simmonds et al.

The sources responsible for the Epoch of Reionization (EoR), the last major phase transition of the Universe, remain highly elusive. While JWST has begun to illuminate the properties of early galaxies, the direct detection of their ionizing photons is virtually impossible due to the neutral intergalactic medium (IGM) at z>6. A direct estimate of the escape fraction of ionizing photons (fesc) is thus not possible. However, the escape fraction is encoded in spectral features that trace a low opaci…

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astro-ph.SRastro-ph.GAastro-ph.IM

BOSS-CLAM: Utilizing a Constrained Linear Absorption Model to Infer Stellar Parameters from BOSS Spectra

Ilija Medan, Andrew R. Casey, Alexander P. Ji, Jonah M. Otto, Kayvon Sharifi, Zachary Way, Madeleine McKenzie, Natalie R. Myers et al.

Large spectroscopic surveys require robust pipelines capable of inferring stellar parameters over a wide range of the Hertzsprung-Russell (HR) diagram from data of varying quality. SDSS-V is one such survey, where the data from the lower-resolution, optical BOSS spectrograph will provide a large dataset covering a wide range of Galactic stellar populations. To better analyze these data, we present BOSS-CLAM, a generative, forward modeling pipeline for inferring effective temperature ($T_\mathrm{…

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astro-ph.EP

SCoRE: the Surface Composition of Rocky Exoplanets

Leon Sereinig, Oliver Herbort

Context. The crust composition of rocky exoplanets with a substantial atmosphere can not be observed directly. However, recent developments are starting to allow for the observation and characterisation of their atmospheres. Understanding the link between atmospheres and crusts could allow for constraints on the crusts' composition based on atmospheric observations. Aims. We aim to understand the link between the thermal stability of specific condensates and atmospheric compositions. This allows…

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astro-ph.COastro-ph.HEhep-phphysics.plasm-ph

Relativistic Chiral MHD with application to the early Universe

Deepen Garg, Jennifer Schober

We present a systematic derivation of the equations of relativistic chiral magnetohydrodynamics (MHD) for a plasma of charged fermions in an expanding universe. Through a combination of a coordinate transformation and a rescaling of the dynamical variables, we bring the full system to the same form as in the Minkowski metric, with the Hubble expansion surviving only in the chirality-flipping rate and the kinematic viscosity. Retaining all four contributions to both the electric and the axial cur…

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astro-ph.COastro-ph.HEphysics.plasm-ph

A charge-flow instability in plasmas with charge fluctuations

Deepen Garg, Jennifer Schober

We present a linear instability in magnetized plasmas with charge fluctuations. It is driven by an electric current proportional to the charge chemical potential $μ$ and the bulk velocity. This charge-flow (C-flow) instability has hitherto not been considered in standard magnetohydrodynamics or its chiral extensions. We derive its dispersion relation and maximum growth rate, and confirm them with direct numerical simulations. We also show that the C-flow instability persists even for zero-mean f…

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astro-ph.GAastro-ph.HEastro-ph.SR

Charting the Galactic Underworld I: Comprehensive simulations of the kinematics, rates, and demographics of Milky Way black holes

Tom Wagg, Katelyn Breivik, Adrian M. Price-Whelan, Mathieu Renzo, Julianne J. Dalcanton, Natasha S. Abrams

With upcoming data from Roman, Gaia DR4, and spectroscopic surveys, we will soon have an unprecedented dataset of Milky Way black holes (BHs) to constrain their formation and evolution. To prepare, we simulate the intrinsic population of Milky Way BHs with cogsworth, self-consistently accounting for their binary evolution and trajectories through the Galactic potential. We report the rate, demographics, and kinematics of these BHs, and their sensitivity to 32 variations in binary evolution, supe…

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astro-ph.GAastro-ph.COastro-ph.HE

Speeding up Gravitational Lens Mass Models with Machine Learning: Applications in X-ray Astronomy

Alex Ostridge, Rafael Martínez-Galarza, Júlia M. Sisk-Reynés, Daniel A. Schwartz, Anna Barnacka

Multi-wavelength observations of quadruply lensed quasars constitute a powerful probe of cosmology, dark matter substructure along the line of sight, and the structure of X-ray emitting regions in high-redshift quasars. These investigations are conditional on acquiring an accurate model for the surface mass density of matter lensing these quasars. We propose a simulation-based machine learning method to accelerate parameter inference in real quadruply lensed systems by several orders of magnitud…

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astro-ph.GAastro-ph.SR

LBT-MODS spectroscopy of young stellar objects in the distant metal-poor star forming region Sh2-284: Stellar and accretion properties

Katia Biazzo, Juan Manuel Alcalá, Felice Cusano, Mario Guarcello, Diego Paris, Ester Marini, Roberta Carini, Teresa Giannini et al.

We present a spectroscopic survey of young stellar objects (YSOs) in Sh2-284, a distant (~4.5 kpc), low-metallicity (Z~1/3 Zsun) star-forming region (SFR) toward the Galactic anticenter. Candidate YSOs were selected using mid-infrared Spitzer/IRAC data with optical and near-infrared photometry. Follow-up spectroscopy was conducted with MODS at the Large Binocular Telescope. We characterize the stellar and accretion properties of the disk-bearing population in a metal-poor environment, probing st…

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astro-ph.GAastro-ph.HEastro-ph.SR

Is S301 the Captured Companion of the Hypervelocity Star S5-HVS1?

Andrea Caputo, Giovanni Maria Tomaselli

Stellar binary disruptions through the Hills mechanism produce two fossils: a hypervelocity star (HVS), and a star tightly bound to the supermassive black hole. Among known galactic HVSs, only S5-HVS1 has unambiguous galactic-centre origin. Its measured mass and velocity determine a relation between the mass and semi-major axis of its captured companion. GRAVITY has now discovered S301, whose orbit and photometrically inferred mass satisfy this relation, making it the only compelling candidate f…

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astro-ph.IM

Pollux: decisions affecting the optical architecture of a high-resolution spectrograph and polarimeter for the Habitable Worlds Observatory

Eduard Muslimov, Luca Fossati, Coralie Neiner, Jean-Claude Bouret, David Le Mignant, Kjetil Dohlen, Jean-Michel Reess, Adrien Girardot et al.

POLLUX is a candidate European instrumental contribution to the Habitable Worlds Observatory. It is a high-resolution spectrograph with polarimetric capabilities, covering from the far ultraviolet (FUV; 100nm) to the near infrared (NIR; 1.75mum). Such a broad spectral coverage is achieved by splitting the instrument into five channels, each comprising an echelle spectrograph: FUV, medium-UV (MUV), near-UV (NUV), optical (OPT), and NIR. A set of custom-made dichroics enables simultaneity across t…

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astro-ph.SRastro-ph.GA

Payne4GAIN: NLTE Corrections for Red Giants in Milky Way Mapper using H-Band Neural Network Emulators

Pierre Thibodeaux, Alexander P. Ji, Nicholas Storm, Maria Bergemann, Rana Ezzeddine, Yuan-sen Ting, Andrew R. Casey, Emily Griffith et al.

The majority of spectroscopic surveys assume local thermodynamic equilibrium (LTE) during the modeling of stellar spectra. This assumption begins to break down for luminous stars, like the red giants targeted by SDSS-V's Milky Way Mapper Survey in its Galactic Genesis program. In this work, we present non-LTE (NLTE) abundances for 360,000 red giant stars in Milky Way Mapper DR19, from infrared APOGEE spectra. We generate NLTE spectra using precomputed departure coefficient grids for Na, Mg, Si,…

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astro-ph.IMastro-ph.EPastro-ph.SR

Optical design of VIPER: a high-resolution multimode fiber-fed VIPA spectrograph for characterizing exoplanet atmospheric escape

Matthew C. H. Leung, David Charbonneau, Andrew Szentgyorgyi, Colby Jurgenson

We present the optical design of VIPER: a high-resolution, multimode fiber-fed, narrowband, cross-dispersed, seeing-limited spectrograph based on a Virtually Imaged Phased Array (VIPA), a spectral disperser that provides higher dispersion and a more compact form factor than conventional diffraction gratings. VIPER is specifically designed to probe exoplanet atmospheric escape through the helium 1083 nm triplet line, with a resolving power of 300,000 over a 10 nm wavelength range. VIPER is intend…

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astro-ph.EP

JWST NIRCam Reveals the Largest Known M-dwarf Debris Disk Around TWA 10 and New Scattered-Light Observations of the TWA 25 Debris Disk

Katie A. Crotts, Aarynn L. Carter, Beth Biller, Mark Booth, Rachel Bowens-Rubin, Raphaël Bendahan-West, Rodrigo Ferrer-Chavez, Kellen Lawson et al.

We present JWST NIRCam observations of two M-dwarf systems located in the TW Hydra association, TWA 10 and TWA 25. Both systems harbor detected debris disks in the F200W and F444W filters. Whereas the TWA 25 disk has been previously imaged, these observations represent the discovery and first images of the TWA 10 disk. In addition to planet searches within these systems, we also conduct an analysis of each debris disk, where the TWA 10 debris disk is characterized for the first time. We find tha…

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astro-ph.SRastro-ph.EP

Spin-spin coupling in stellar binaries

Alexandre C. M. Correia

Spin-orbit misalignment is increasingly observed in binary stars, but its origin remains uncertain. We study the secular spin dynamics of stellar binaries and derive the associated Cassini states. We isolate a spin-spin resonance that arises when the two stellar spin-precession frequencies become commensurate. This resonance can excite the obliquity of the secondary to high values even when the primary is only weakly tilted. Magnetic braking favors the formation of high-obliquity states, whereas…

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astro-ph.HEastro-ph.GA

Winds Versus Jets in Active Galactic Nuclei

David Garofalo, Chandra B. Singh, Atticus Magerko, Marco Botello, Sophia Soto, Max North

The well-established anti-correlation between disk winds and relativistic jets in X-ray binaries is often interpreted in a scale-invariant black hole accretion context. If so, active galactic nuclei (AGN) should exhibit a direct mass-scaled analog. We test this prediction across FRII radio quasars, radio-quiet quasars, and jetted and non-jetted Narrow Line Seyfert 1 galaxies (NLS1) in spirals, among others. They exclude simple scale invariance. The highest-velocity winds occur exclusively in rad…

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astro-ph.IMastro-ph.GAastro-ph.SR

HRMOS: a very high-resolution, multi-object spectrograph for the ESO VLT

Andrea Bianco, Sofia Randich, Emma Fernandez Alvar, Oscar Gonzalez, Sergio Sousa, Thomas Bensby, Letizia Caito, Enrico Giro et al.

HRMOS (High-Resolution Multi-Object Spectrograph) is a proposed new instrument for the ESO Very Large Telescope (VLT) developed in the context of the ESO VLT Beyond 2030 call. It is designed to fill a unique and currently unoccupied region in the observational landscape: the combination of very high spectral resolution (R=80,000) with multi-object capability (50-60 simultaneous targets), a radial-velocity (RV) precision of 10m/s, and coverage of three key spectral windows (385-421nm, 480-522nm,…

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astro-ph.EPastro-ph.SR

A closer look at the WISPIT 2 host star. Evidence for a spectroscopic binary

Cade J. Bürgy, Myriam Benisty, Hala Alqubelat, Carlo F. Manara, Stefano Facchini

While hundreds of protoplanetary discs have been studied in great detail, the detection of protoplanets still embedded in their native discs remains rare. WISPIT 2 is only the second laboratory allowing for direct study of planet formation while in progress. The recently discovered system hosts two giant protoplanets in a multi-ringed disc. Here, we aim at characterising the WISPIT 2 host star spectroscopically to determine its stellar properties, accretion rate, and inner disc diagnostics, prov…

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astro-ph.HEastro-ph.IM

4th TDAMM Workshop White Paper

Daniel Kocevski, Raffaella Margutti, Michael Coughlin, Christopher Fryer, Kate Alexander, Igor Lorenzo Andreoni, Jean-Luc Atteia, Elias Aydi et al.

Time-Domain and Multi-Messenger Astrophysics (TDAMM) is entering a new era in which the rate and diversity of transient discoveries will grow rapidly across electromagnetic, gravitational-wave, neutrino, and cosmic-ray facilities. The scientific return from these investments will increasingly depend not on discovery alone, but on the ability to identify, prioritize, and coordinate follow-up observations across a heterogeneous and globally distributed network of observatories. This white paper su…

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astro-ph.IM

ANDES, the high-resolution spectrograph for the ELT: design and performance analysis of the YJH spectrograph

Vinooja Thurairethinam, David Lee, James Stevenson, Étienne Artigau, Frédérique Baron, Ciarán Breen, Bella Boyd, Denis Brousseau et al.

The ArmazoNes high Dispersion Echelle Spectrograph (ANDES) is a powerful second-generation high-resolution spectroscopic instrument for the Extremely Large Telescope (ELT). The UBV, RIZ, and YJH modules comprise fibre-fed spectrographs of the ANDES baseline design and will offer continuous wavelength coverage of 0.35-1.8 $μ$m, with the addition of a K-band channel providing coverage up to 2.4 $μ$m. Coupled with a spectral resolution of $\sim$100,000, ANDES must deliver the required wavelength ca…

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astro-ph.IM

ANDES, the high-resolution spectrograph for the ELT: design and performance analysis of the YJH spectrograph

Vinooja Thurairethinam, David Lee, James Stevenson, Étienne Artigau, Frédérique Baron, Ciarán Breen, Bella Boyd, Denis Brousseau et al.

The ArmazoNes high Dispersion Echelle Spectrograph (ANDES) is a powerful second-generation high-resolution spectroscopic instrument for the Extremely Large Telescope (ELT). The UBV, RIZ, and YJH modules comprise fibre-fed spectrographs of the ANDES baseline design and will offer continuous wavelength coverage of 0.35-1.8 $μ$m, with the addition of a K-band channel providing coverage up to 2.4 $μ$m. Coupled with a spectral resolution of $\sim$100,000, ANDES must deliver the required wavelength ca…

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astro-ph.SR

Detection of pulsations and a non-stable wind in IRAS 01005+7910, an object with the B[e]-phenomenon

Anatoly S. Miroshnichenko, Valentina G. Klochkova, Vladimir E. Panchuk, Ekaterina S. Islentieva

Comparison of the spectra obtained at different observing dates shows significant variations in the complex H$α$ and H$β$ line profiles, such as a systematic increase in their emission peak strengths in 2025$÷$2026 compared to those observed in 2013 as well as a strong variability in their wind component. A detected variable radial velocity $V_{\odot}$ from $-20$ to $-68$ km/s with a standard deviation of the mean value of K$\sim$8.0 km/s can be interpreted as a result of pulsations or the prese…

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hep-exastro-ph.HE

Proton-air interaction properties at $\sqrt{s} \simeq 100$ TeV from shower-depth measurements with the Pierre Auger Observatory and their connection to the Muon Puzzle

The Pierre Auger Collaboration, A. Abdul Halim, P. Abreu, M. Aglietta, M. Ahmed, I. Allekotte, K. Almeida Cheminant, R. Aloisio et al.

Hybrid measurements at the Pierre Auger Observatory indicate that most high-energy hadronic interaction models underestimate the average depth of the shower maximum, $\langle X_{\max} \rangle$, at a center-of-mass energy of $\sqrt{s}=97.7 \pm 0.4^{+6.6}_{-6.2}\,\mathrm{TeV}$. In this Letter, the hadronic interaction models are shown to follow a universal relation between the predicted $\langle X_{\max} \rangle$ and the mean values of variables characterizing the energy spectra of secondary parti…

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astro-ph.SRastro-ph.HE

Discovery of a radio-flaring M dwarf in a commensal transient search of the LADUMA field

Moses Mlangeni, Patrick A. Woudt, Paul J. Groot, Alex Andersson, Zwidofhela N. Khangale, Francesco Cavallaro, Steven Bloemen, Paul Vreeswijk et al.

We report the discovery and characterisation of MKT J032848.4-271904.6, a new radio transient identified in the LADUMA field using SARAO Science Data Processor (SDP) UHF-band images from approximately one year of MeerKAT observations. Using the Transient Pipeline (TraP) and advanced filtering techniques, we identified a number of candidate variable radio sources in the field. All but one show variability consistent with refractive interstellar scintillation, leaving MKT J032848.4-271904.6 as the…

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astro-ph.IM

METIS for ELT: optical alignment and testing of the IFU of the LM-band spectrometer

Lawrence Bissell, Éamonn Harvey, Stephen Todd, Valentina Oyarzun, Alastair Macleod, Sandi Wilson, Alistair Glasse, Daniel Dicken et al.

The METIS LMS (LM-band Spectrometer) is a high-resolution (R>100,000) mid-infrared integral field spectrometer for the ESO ELT. The instrument provides the capability to measure instantaneous spectra across a 0.577 x 0.897 arcsecond field-of-view with a spatial sampling of 8.2-9.1 mas using an image slicing IFU. This paper presents the optical testing and alignment performed for the IFU sub-system. This includes the detailed characterisation of the image slicing mirror array measured via: a re-i…

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astro-ph.SRastro-ph.GA

Ensemble Kinematic Ages for 1.5 Million LAMOST Stars

Yuxi Lu, Marc H. Pinsonneault

We present a framework for inferring stellar ages from spectroscopic stellar parameters, calibrated with ensemble kinematics by averaging over the median vertical action, $J_z$, for stars with similar atmospheric and chemical properties, yielding self-consistent age estimates across the Hertzsprung-Russell (HR) diagram. We refer to these ages as ensemble kinematic ages as the age scale is calibrated from the average kinematics of ensembles of stars with similar stellar parameters. Individual ste…

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astro-ph.IM

CUBES: optical design and analysis of the VLT's high-resolution UV spectrograph past final design review

Lawrence Bissell, Walter Seifert, Ariadna Calcines Rosario, Hans Dekker, Gerardo Avila, Luca Oggioni, Giorgio Pariani, Matteo Genoni et al.

CUBES (Cassegrain U-Band Efficient Spectrograph) will be the most efficient UV spectrograph on an 8-10m class telescope, exploiting the ESO VLT's higher telescope efficiency relative to the ESO ELT in ground-based UV wavelengths. The instrument provides wavelength coverage over a range of 300-405nm, with high instrumental efficiency (>37%) and a resolving power of >20,000 (HR) and >6,000 (LR). It will be mounted on the Cassegrain focus of the VLT in Paranal. This paper presents the optical desig…

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astro-ph.HEastro-ph.SR

Exploring the optical properties of redback pulsars: The case of J1717+4308A in the globular cluster M92

Jianxing Chen, Greta Ettorre, Cristina Pallanca, Mario Cadelano, Bidisha Sen, Devina Misra, Emanuele Dalessandro, Francesco R. Ferraro et al.

Binary millisecond pulsars (MSPs) in globular clusters (GCs) are key for binary and stellar evolution studies under extreme conditions. The identification of their optical companion stars is instrumental in order to characterise these systems and to constrain the possible recycling mechanisms. For this work, we searched for the optical counterpart to PSR J1717+4308A (hereafter M92A) in the GC M92. To this end, we exploited a multi-epoch, multi-wavelength dataset obtained with the Hubble Space Te…

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astro-ph.IM

HARMONI at ELT: LPOU calibrations for a micron-level pointing accuracy

Gonzalo José Carracedo Carballal, Irene Ferro Rodríguez, David L King, Iago Funes Vecino, Guillermo Mercant Rubio, Alonso Álvarez Urueña, Laura García Moreno, Heribert Argelaguet Vilaseca et al.

HARMONI is the first light, adaptive optics assisted, near-IR integral field spectrograph for the ELT [1]. It covers a spectral range from 800 nm to 2450 nm with resolving powers from 3000 to 7000 and spatial sampling of 25 mas and 6mas. It can operate in two adaptive optics modes, SCAO (including a high contrast capability) and MCAO. The project is resuming its final design phase after a rescope design phase in 2025. To achieve its optimal image quality, HARMONI needs to perform pointing error…

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astro-ph.IM

HARMONI at ELT: Design & Test on the current status of Low Order Wavefront Subsystem Pick Off Arm Engineering Model (LPOA-EM)

Iago Funes Vecino, Guillermo Mercant Rubio, Alonso Álvarez Urueña, Laura García Moreno, Gonzalo José Carracedo Carballal, Irene M. Ferro Rodríguez, Heribert Argelaguet Vilaseca, Javier Piqueras López et al.

HARMONI is the first-light, adaptive-optics-assisted, near-infrared integral field spectrograph for the ELT, covering 800 to 2450 nm with resolving powers from 3000 to 7000. The Low Order Wavefront Sensor subsystem (LOWFS) provides field stabilisation by measuring the motion of the instrument focal plane relative to the telescope wavefront sensors. Following a rescope process in 2025, LOWFS has been updated to operate three LOWFS Pick-Off Arms (LPOA) simultaneously within a shared volume. We pre…

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astro-ph.GA

When Two Worlds Collide: How Collisions Between Silicate and Carbonaceous Nanograins can Drive Complex Chemistry

Alexandros Kyriazis, Albert Rimola, Stefan T. Bromley

Our overall objective is to determine how collision velocity governs the interactions between silicate and carbonaceous nanograins. We aim to: i) identify collisional regimes capable of producing mixed silicate-carbonaceous grains and/or chemically complex molecular species, and ii) quantify fragmentation threshold velocities related to dust destruction. We performed molecular dynamics simulations employing a machine-learning force field to model head-on collisions between silicate and carbonace…

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