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Research Trends

Latest preprints in space engineering and astrophysics.

astro-ph.SR

Coronal Green-Line Emission During a Solar Prominence Eruption: Spectroscopic Evidence of Its Correspondence with the EUV Late Phase

P. Vemareddy, R. Ramesh, V. Muttu Priyal

We report spectroscopic observations during a prominence eruption on 9 October 2025 from the Sun's west limb, associated with an M2.0 flare that commenced at 12:11 UT. The event was captured in sit-and-stare mode by the Visible Emission Line Coronagraph (VELC) onboard Aditya-L1, providing continuous observations of the Fe XIV 5303 Åcoronal greenline. The spatially averaged green-line emission exhibits a clear correspondence with the EUV late-phase (ELP) emission observed in multiple SDO/AIA chan…

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astro-ph.GAastro-ph.IM

CERIDWEN: Fast and Flexible GPU-Accelerated Stellar Population Inference

Amanda Stoffers, Sandro Tacchella, Benjamin D. Johnson

JWST has increased both the number of high-redshift galaxies with high-quality spectral energy distributions (SEDs) and their information content. In parallel, wide-area surveys from Euclid, Rubin's LSST, and Roman will increase galaxy samples by orders of magnitude. Analysing these datasets requires stellar-population models that are both flexible and computationally efficient. We present CERIDWEN, a GPU-native SED fitting framework written in JAX, with an end-to-end differentiable forward mode…

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gr-qcastro-ph.HE

Stiffness corrections for f-mode neutron star universal relations

Isaac G. Chu, Carolyn A. Raithel

Excitations of the neutron star (NS) fundamental mode (f-mode) during a binary NS inspiral or from a glitching pulsar can produce gravitational waves (GWs) that will be detectable with the next generation of detectors, opening the door to GW asteroseismology of neutron stars. There exist approximately equation-of-state (EOS)-insensitive, or "universal," relations that relate the f-mode to other NS properties. These universal relations have typically been identified with relatively small, selecti…

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astro-ph.SR

Formation of adducts of C$_6$H with Na$^+$, Mg$^+$ and Al$^+$ metal cations by radiative association

Niyazi Bulut, Octavio Roncero, Maria Mallo, German Molpeceres, Marcelino Agundez, Maysa Yusef-Buey, Jose Cernicharo, Carlos Cabezas et al.

The Mg-bearing cations MgC$_4$H$^+$, MgC$_6$H$^+$, MgC$_3$N$^+$, and MgC$_5$N$^+$ have been recently observed in the carbon-rich envelope IRC\,+10216. These species are thought to form upon radiative association between Mg$^+$ and the corresponding neutral radical. This work aims to determine the radiative association rate coefficients for the cations Al$^+$, Mg$^+$, and Na$^+$ reacting with carbon chain radicals to estimate the relative importance of metal-bearing carbon cations for each of the…

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astro-ph.SR

Formation of adducts of C$_6$H with Na$^+$, Mg$^+$ and Al$^+$ metal cations by radiative association

Niyazi Bulut, Octavio Roncero, Maria Mallo, German Molpeceres, Marcelino Agundez, Maysa Yusef-Buey, Jose Cernicharo, Carlos Cabezas et al.

The Mg-bearing cations MgC$_4$H$^+$, MgC$_6$H$^+$, MgC$_3$N$^+$, and MgC$_5$N$^+$ have been recently observed in the carbon-rich envelope IRC\,+10216. These species are thought to form upon radiative association between Mg$^+$ and the corresponding neutral radical. This work aims to determine the radiative association rate coefficients for the cations Al$^+$, Mg$^+$, and Na$^+$ reacting with carbon chain radicals to estimate the relative importance of metal-bearing carbon cations for each of the…

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nucl-thastro-ph.HE

Extending multi-messenger constraints on neutron star matter through the inclusion of direct Urca cooling

M. Dio Danarianto, Guilherme Grams, Thibeau Wouters, Tim Dietrich

The properties and behavior of strongly interacting matter at extreme densities can not only be determined through terrestrial experiments or through theoretical considerations, but also astrophysical observations of neutron stars (NSs) and binary neutron star systems become increasingly important to obtain complementary information. In light of these findings, we perform a Bayesian study inferring the NS equation of state (EoS) by incorporating constraints from the direct Urca (dUrca) process,…

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astro-ph.EP

Deep HST/STIS Coronagraphic Imaging of the $β$ Pictoris Debris Disk: On the Scattered Light Component of the Cat's Tail

Arin M. Avsar, Kevin Wagner, Daniel Apai, Isabel Rebollido, Antranik A. Sefilian, Marshall D. Perrin, Christopher C. Stark, Gabriel Weible et al.

The $β$ Pictoris debris disk is a unique system where mid-infrared coronagraphic imaging with JWST/MIRI revealed a new spatially resolved substructure known as the Cat's Tail. We present deep HST/STIS coronagraphic imaging of $β$ Pic in scattered light, combining six epochs of observations between 2012 and 2025, in search of the scattered light component of the Cat's Tail. We detect the disk out to a projected separation of 500 au for the first time with HST/STIS, achieving SNR > 100 across much…

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astro-ph.HE

A Helical Trajectory Interpretation of a Multi-wavelength Event in a Blazar S5 0716+714

Zhihao Ouyang, Jingyu Wu, Hubing Xiao, Zhijian Luo, Zhu Chen, Shaohua Zhang, Liang Chen, Jianzhen Chen et al.

Relativistic jets in blazars exhibit strong variability across multiple timescales, but the connection between temporal variability and the evolution of jet structures remains poorly understood. In this work, we investigate the $γ$-ray variability of the BL Lac object S5 0716+714 from July 2014 to June 2015 and explore its possible connection with the parsec-scale jet evolution. We identify an escalating periodic oscillation (EPO) in the $γ$-ray light curve, characterized by a sequence of succes…

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astro-ph.SR

DKIST unveils MHD-predicted sub-50 km photospheric vortices

S. Vargas Dominguez, O. A. Calvo Rebellon, J. S. Castellanos Duran, M. van Noort, F. Wöger, D. A. Rodriguez Torres, C. G. Bernal

Solar vortices are rotating plasma structures that play a key role in the transport of energy and magnetic helicity from the photosphere to the chromosphere and corona. While numerical simulations predict the existence of small-scale photospheric vortices with diameters of $50$--$100$ km, no direct observational evidence has been reported to date, primarily because of the limited spatial resolution of previous instrumentation. Here, we analyze high-resolution observations obtained with the 4-met…

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astro-ph.EP

The GAPS programme at TNG LXXIX. New mass constraints for the infant planets in the V1298 Tau system through a long-term radial velocity monitoring with HARPS-N

M. Damasso, P. Leonardi, L. Borsato, S. Benatti, A. Suárez Mascareño, A. Bonfanti, C. Di Maio, M. Mallorquín et al.

We aim to constrain the dynamical masses of the four confirmed transiting planets orbiting the infant ($20\pm10$ Myr) star V1298,Tau (orbital periods $P_b\sim$24.1 d, $P_c\sim$8.2 d, $P_d\sim$12.4 d, and $P_e\sim$48.7 d), through a new analysis of a homogeneous radial velocity dataset. This system is a key benchmark for testing formation and early-stage evolutionary models of planets. We analysed more than 380 high-resolution spectra collected with the HARPS-N spectrograph over a time span of 4.…

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astro-ph.GA

The JWST and ALMA view of local dwarf Pox 186: Evidence of stripped binaries driving a hard radiation field and little cold molecular gas resulting in high star-formation efficiency

Nimisha Kumari, Renske Smit, Claus Leitherer, J. Álvarez-Márquez, Katherine Ormerod, Joris Witstok, Suzanne Madden, Matthew Hayes et al.

We present a JWST mid-infrared (MIR) view of Pox 186, one of the best local analogs of reionization-era galaxies based on its extreme properties in the ultraviolet, optical, and far-infrared (FIR). We extracted a high signal-to-noise spectrum of Pox 186 from the spatially resolved MIR data taken with the Medium Resolution Spectrometer (MRS) on the MIR Instrument (MIRI), and compared its MIR properties with those of the other dwarf galaxies in the Herschel Dwarf Galaxy Survey. We probe the radiat…

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astro-ph.COastro-ph.GA

Two-rung ladder: $H_0$ from Tip of the Red Giant Branch and geometric anchors alone

Richard Stiskalek, Harry Desmond, Guilhem Lavaux

We infer the Hubble constant $H_0$ from the ~400 Extragalactic Distance Database hosts with a tip of the red giant branch (TRGB) distance, calibrated on the geometric anchors of the Large Magellanic Cloud and NGC 4258. We forward-model the tip magnitudes and host redshifts including magnitude-limited selection, sky exposure, and density-dependent galaxy bias, conditioning on each of the 80 Manticore-Local realisations of the local density and peculiar-velocity fields in turn. As most hosts lie a…

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astro-ph.GA

PAHSPECS: JWST/MIRI Spectroscopy of PAHs at Cosmic Noon

Irene Shivaei, Tanio Díaz Santos, Leindert A. Boogaard, Karin Sandstrom, Cristina Lofaro, Fergus R. Donnan, Pablo G. Pérez González, Roman Fernández Aránda et al.

The physical conditions of the interstellar medium (ISM) are thought to differ greatly at high redshifts compared to local galaxies. Polycyclic aromatic hydrocarbons (PAHs) are key ISM constituents, mediating the heating and cooling of gas in photo-dissociation regions. However, PAHs are unexplored in main-sequence (MS) galaxies at z~1-2 (cosmic noon), limiting our view of the ISM's thermal and chemical balance. We present the PAH Spectroscopic Survey (PAHSPECS) JWST program, the first MIRI/MRS…

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astro-ph.HEastro-ph.GA

Exceptional Gamma-Ray Flaring Activity of the Blazar S4 0954+65 in Early 2025

Zhihao Ouyang, Jingyu Wu, Hubing Xiao, Lili Yang, Shangchun Xie, Shaohua Zhang, Zhijian Luo, Jianzhen Chen et al.

S4 0954+65 (4FGL J0958.7+6534) is a TeV-detected blazar at a redshift of $z = 0.3694 \pm 0.0011$, classified as an intermediate-synchrotron-peaked BL Lac object. In early 2025, it entered an exceptional $γ$-ray high state. We aim to investigate the origin and physical properties of the exceptional 2025 flare, and to constrain the emission processes responsible for this flaring activity. We performed a multi-wavelength analysis using $γ$-ray, X-ray, optical/UV, radio, and 43 GHz Very Long Baselin…

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astro-ph.IM

Simultaneous PSF Matching via Dual Kernel Optimization

Carter Lee Rhea, Pieter Van Dokkum, Roberto Abraham, Imad Pasha, Steven R. Janssens, William P. Bowman, Deborah Lokhorst, Seery Chen et al.

Standard point spread function (PSF) matching algorithms consider one image as the reference and aim to find a convolution kernel such that, when applied to the reference image, the PSFs of the reference and non-reference images are matched. This method works well if one image is a degraded version of the other. However, this is not always the case: if the PSFs of the two images have different orientations or shapes, a simple convolution of one of the images does not lead to a satisfactory match…

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astro-ph.GAastro-ph.CO

Discovery of an isolated RELHIC Candidate: J1351+0039

Jin-Long Xu, Alejandro Benitez-Llambay, Ming Zhu, Chuan-Peng Zhang, Nai-Ping Yu, Xiao-Lan Liu, Mei Ai, Ruilei Zhou et al.

We report the discovery of J1351+0039, a new isolated dark galaxy candidate identified through a blind HI survey with the Five-hundred-meter Aperture Spherical radio Telescope (FAST), combined with deep optical imaging from the DESI Legacy Survey. The object displays a compact HI structure with a systemic velocity of V_{LSR} = 429.0 \kms and an inferred HI mass of 4.8*10^5 Msun. No optical counterpart is detected in the DESI images, with a g-band surface brightness limit of 28.1 mag arcsec^{-2},…

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astro-ph.EPastro-ph.IM

Extracting Asteroid Physical Properties from Vera C. Rubin Observatory Science Validation Survey Data: Rotational Periods, Colors, and Taxonomies

V. Carruba, S. Greenstreet, M. Mastropietro, S. Aljbaae, G. Caritá, R. C. Domingos, M. Huaman, M. M. Bala et al.

The Vera C. Rubin Observatory will enable large-scale characterization of minor bodies through high-cadence, multi-band photometry. Early Science Validation (SV) observations from 2025-2026 provide one of the first extensive datasets for Solar System studies, but typically with sparser and more heterogeneous coverage than the Rubin First Look data, where hundreds of observations were available for well-characterized objects. In this work, we build on the methodology developed for the Rubin First…

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astro-ph.SRastro-ph.HE

A Multiwavelength View of $ρ$ Oph II: Disentangling the Variability of the Multi-Star Component C

Sean J. Gunderson, Walter W. Golay, Jackson Codd, David P. Huenemoerder, Felipe Navarete, Christiana Erba, Alexandrea Moreno, John M. Cannon et al.

We present a multiwavelength analysis of the star $ρ$ Oph C, covering X-ray, optical, near-infrared, and radio observations to test for the presence of interferometrically-detected cool star companions. The X-ray observations from Chandra, XMM-Newton, and NuSTAR show flare-like events lasting minutes or days in time and spectral properties consistent with those of cooler stars instead of the primary magnetic B star. The near-infrared data is also consistent with the proposed trinary system prope…

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astro-ph.HE

Observational signatures of warped accretion flows in tidal disruption events

Andrew Mummery, Eliot Quataert

We analyze the possible observational signatures and evolution of global warps in the accretion flows produced in tidal disruption events. These warps are driven by Lense-Thirring torques resulting from the misalignment of the disk's rotation axis and the black hole's spin axis. In a previous paper we argued that these global warps should be generically present in TDE accretion flows as they enter a late-time thin disk phase of evolution. We isolate three possible observational signatures of war…

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astro-ph.EPastro-ph.IM

VLTI/MATISSE observations of the hot dust around $β$ Pictoris: Observing faint objects with MATISSE

P. Priolet, J. -C. Augereau, J. Milli, A. Matter, B. Lopez, H. Beust, J. Varga, P. Boley et al.

Context: Hot exozodiacal dust has been detected around approximately 20% of nearby main-sequence stars, indicating that it is a common feature of extrasolar planetary systems. However, its spatial distribution and grain properties remain poorly understood. Aims: We aim to show that the spatial distribution of hot dust around beta Pictoris, an iconic planetary system with two known planets and a population of exocomets, can be constrained through a detailed analysis of optical long-baseline inter…

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astro-ph.GA

How Magnetic Fields Regulate Cooling and Mixing in Turbulent Radiative Mixing Layers

Rajsekhar Mohapatra, Lachlan Lancaster, Drummond Fielding, Eliot Quataert, Greg L. Bryan

Turbulent radiative mixing layers (TRMLs) are expected wherever hot and cold gas move past one another, including in the solar corona, galactic winds, and cold filaments in galaxy clusters. These environments are often magnetized, but magnetic effects on mixing and cooling remain less well understood than in the hydrodynamic (HD) case. We present magnetohydrodynamic (MHD) simulations of TRMLs at resolutions up to $1024 \times 2048^2$, spanning fields aligned with and transverse to the shear, and…

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astro-ph.SRnucl-th

Quantum Phase Transitions in Nuclei and the Origin of Rhodium

P. Agarwal, H. Schatz, A. Francis, F. Montes, B. Pol, L. Roberts

The astrophysical rapid neutron capture process (r-process) is a major nucleosynthesis process responsible for the production of elements heavier than copper. Prominent features in the observationally inferred r-process abundance distributions provide critical clues for astrophysical conditions and possible r-process sites. The lack of clear features for the r-process elements lighter than tellurium has led to a broad range of proposed possible scenarios and alternative processes that may produc…

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gr-qcastro-ph.GA

Environmental Imprints of Dark Matter and Accretion Disks on Eccentric EMRIs around Kerr Black Holes

Hai-Chao Yuan, Yong Tang

Extreme-mass-ratio inspirals (EMRIs), systems in which a stellar-mass compact object spirals into a supermassive black hole ($M_1$), are prime targets for the space-based gravitational-wave interferometers and are acutely sensitive to their astrophysical environment. We quantify the joint imprint of a dark matter (DM) spike and an accretion disk on the waveforms of eccentric, equatorial Kerr EMRIs, integrating four modular effects---DM dynamical friction, DM self-gravity, Newtonian accretion-dis…

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gr-qcastro-ph.HEhep-phnucl-th

Multi-messenger and multi-band signal from first-order phase transitions in proto-neutron stars

Christian Ecker, Mauro Giliberti, Luciano Rezzolla

A first-order phase transition (PT) alters a compact star on two scales: globally, via growth of a quark-matter core, and microscopically, via collision of quark bubbles, driving a simultaneous gravitational-wave (GW) emission in the kHz and MHz bands. Using a constrained ensemble of model-agnostic equations of state, we follow the accretion-driven evolution of proto-neutron stars through the PT and compute the resulting multi-band GW signal. The correlations found between the kHz emission and t…

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astro-ph.HEastro-ph.GA

AGN winds and outflows: from accretion-disc scales to the host galaxy

Delphine Porquet

Ultra-fast outflows (UFOs), launched from the inner accretion disc in active galactic nuclei (AGN), are among the prime candidates for driving AGN feedback in their host galaxies. Determining their physical properties and energetics is therefore essential for assessing their impact on galaxy evolution. This review highlights recent observational progress, with particular emphasis on the groundbreaking insights enabled by high-resolution X-ray spectroscopy. The first X-Ray Imaging and Spectroscop…

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astro-ph.GA

Galaxy And Mass Assembly (GAMA): The Most Isolated GAMA Galaxies

Steven Phillipps, Roberto De Propris, Malcolm N. Bremer, Phil A. James, Andrew M. Hopkins

While galaxies generally live in clusters and groups, particularly small groups, or other structures such as walls or filaments, some galaxies appear relatively `isolated', i.e. lacking in close neighbours. Here we use the GAMA survey, and an objective measure of isolation, to explore the most isolated galaxies. We then determine whether these have particular physical characteristics. We find that, as expected, while grouped galaxies split between blue, disk-like and star forming and red, sphero…

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astro-ph.GAastro-ph.CO

Spatial segregation as the origin of anisotropic satellite quenching in haloes and beyond

Zhuoming Zhang, Weiguang Cui, Yun Chen, Romeel Davé

Satellite galaxies in massive halos are seen to be preferentially quenched along the major axes of their central galaxies. In contrast, the AGN jet tends to point along the minor axis, which imposes interesting constraints on the role of AGN feedback in satellite galaxy quenching. Here we use the SIMBA, TNG100, EAGLE, and feedback-free SIMBA cosmological simulations at $z=0$ to show that this satellite anisotropy primarily originates from spatial segregation between quenched and unquenched popul…

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astro-ph.SR

Estimates of magnetic field strength in the solar corona using observations of thermal radio emission at low frequencies

Shaik Sayuf, Kathiravan C, Ramesh C

Measurements of the magnetic field strength in the solar corona at heliocentric distances $r\,{\gtrsim}\,1.1\,R_{\odot}$, using observations other than transient radio bursts, are rare. Circular polarization observations of thermal bremsstrahlung radio emission at frequencies $ }\,1.1R_{\odot}$ in the solar corona, can be effectively used for this purpose. The thermal bremsstrahlung emission is randomly polarized, but in the presence of a magnetic field it propagates in two oppositely polarized…

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astro-ph.GA

Potential binary supermassive black holes in Markarian 231 as a scientific case for the spectropolarimeter POLLUX

Biedermann. J, Marin. F, Neiner. C, Bouret. Jean-Claude

It is now widely accepted that a supermassive black hole (SMBH) resides in the core of nearly every galaxy. Within the context of mergers of galaxies, the central SMBHs from each system should form a gravitationally bound binary system. Given the frequency of galaxy mergers throughout cosmic time, the existence of such binary SMBHs is likely to occur within active galactic nuclei. However, identifying them observationally remains highly challenging. The majority of reported candidates rely on in…

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astro-ph.GA

Probing binary supermassive black hole in quasars tough spectropolarimetry

J. Biedermann, F. Marin

Nearly all galaxies are believed to host a supermassive black hole at their center. In the context of galaxy mergers, the SMBHs from the progenitor galaxies are expected to form a bound binary system. Given the high frequency of such mergers throughout cosmic time, binary SMBHs should be relatively common in active galactic nuclei (AGNs). Yet, their direct detection remains a major observational challenge, with most candidates inferred only through indirect signatures. The quasar Markarian 231 p…

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