RAS_WEB (Page 38)

Scalar Field Dark Matter Around Charged Black Holes Yuri Ravanal, Gabriel G’omez, Normal Cruz arXiv:2404.06774v1 Announce Type: new Abstract: In this paper, we investigate the behavior of a massive scalar field dark matter scenarios in the large mass limit around a central Reissner-Nordstr”{o}m black hole. This study is motivated by observations from the Event Horizon Telescope collaboration, which does not exclude the possibility of the existence of such black holes. Through these inquiries, we uncover that the electric charge may significantly impact the scalar field profile and the density profile in the vecinty of the black hole. For the maximum electric charge allowed by theRead More →

Gravitational production of massive scalars in the context of inflation Urjit A. Yajnik arXiv:2404.06785v1 Announce Type: new Abstract: We set up a formalism for calculating the energy density generated in a quantized massive scalar field in the course of the drastic change in spacetime geometry at the end of the inflationary era. The calculation relies on the notion of adiabatic vacuum. The Bogolubov coefficients are computed by employing the sudden approximation. After obtaining a general formula, we calculate explicitly the energy density generated in a particle species with $m/H ll1$, where $m$ is the particle mass and $H$ is the Hubble constant during the inflationaryRead More →

Impact of far-side structures observed by Solar Orbiter on coronal and heliospheric wind simulations Barbara Perri, Adam Finley, Victor R’eville, Susanna Parenti, Allan Sacha Brun, Antoine Strugarek, ‘Eric Buchlin arXiv:2404.06794v1 Announce Type: new Abstract: Solar Orbiter provides unique capabilities to understand the heliosphere. In particular, it has made observations of the far-side of the Sun and provides unique information to improve space weather monitoring. We aim to quantify how far-side data will affect simulations of the corona and the interplanetary medium, especially in the context of space weather forecasting. We focused on a time period with a single sunspot emerging on the far-side in FebruaryRead More →

Constraining Cosmological Physics with DESI BAO Observations Deng Wang arXiv:2404.06796v1 Announce Type: new Abstract: The DESI year one observations can help probe new physics on cosmological scales. In light of the latest DESI BAO measurements, we constrain four popular cosmological scenarios including inflation, modified gravity, annihilating dark matter and interacting dark energy. Using a data combination of BICEP/Keck array, cosmic microwave background and DESI, we obtain the $1sigma$ and $2sigma$ constraints on the tensor-to-scalar ratio $r_{0.05}= 0.0176^{+0.0070}_{-0.0130}$ and $r_{0.05}=0.018^{+0.020}_{-0.017}$. Using the combination of cosmic microwave background and DESI, we find a $2.4sigma$ evidence for gravitational theories beyond the general relativity, shrinks the dark matter annihilationRead More →

Probing the shape of the brown dwarf desert around main-sequence A-F-G-type stars using post-common-envelope WD$-$BD binaries Zhangliang Chen, Yizhi Chen, Chen Chen, Hongwei Ge, Bo Ma arXiv:2404.06845v1 Announce Type: new Abstract: Brown dwarfs (BDs) possessing masses within the range $40-60 M_{rm Jup}$ are rare around solar-type main-sequence (MS) stars, which gives rise to the brown dwarf desert (BDD). One caveat associated with previous studies of BDD is the relatively limited sample size of MS$-$BD binaries with accurately determined BD masses. We aim to produce a large sample of brown dwarf companions with precisely determined mass around main-sequence A-F-G type stars using observations of post common-envelopeRead More →

Hydrodynamic simulations of WD-WD mergers and the origin of RCB stars Sagiv Shiber, Orsola De Marco, Patrick M. Motl, Bradley Munson, Dominic C. Marcello, Juhan Frank, Patrick Diehl, Geoffrey C. Clayton, Bennett N. Skinner, Hartmut Kaiser, Gregor Daiss, Dirk Pfluger, Jan E. Staff arXiv:2404.06864v1 Announce Type: new Abstract: We study the properties of double white dwarf (DWD) mergers by performing hydrodynamic simulations using the new and improved adaptive mesh refinement code Octo-Tiger. We follow the orbital evolution of DWD systems of mass ratio q=0.7 for tens of orbits until and after the merger to investigate them as a possible origin for R Coronae Borealis (RCB)Read More →

A correlation between hard X-rays and neutrinos in radio-loud and radio-quiet AGN Emma Kun, Imre Bartos, Julia Becker Tjus, Peter L. Biermann, Anna Franckowiak, Francis Halzen, Santiago del Palacio, Jooyun Woo arXiv:2404.06867v1 Announce Type: new Abstract: The production mechanism of astrophysical high-energy neutrinos is not yet understood. A common assumption is that beamed relativistic outflows (jets) driven by accreting black holes are needed to accelerate particles to such high energies to produce high-energy neutrinos. Indeed, the first astrophysical high-energy neutrino source candidate identified by IceCube at a significance level of $>3sigma$ was a blazar — an AGN with an accreting supermassive black hole that drivesRead More →

Magnetic Configuration of Active Regions Associated with GLE Events Regina A. Suleymanova, Leonty I. Miroshnichenko, Valentina I. Abramenko arXiv:2404.06877v1 Announce Type: new Abstract: Charged particles, generated in solar flares, sometimes can get extremely high energy, above the 500 MeV level, and produce abrupt ground level enhancements (GLEs) on the ground-based detectors of cosmic rays. The initial flares are strong eruptions and they should be originated from active regions (ARs). A list of GLE events and associated flares was initially available, and our aim here was to find the hosting AR for each GLE event. Moreover, we aimed to classify the revealed ARs using the magneto-morphologicalRead More →

PROJECT-J: JWST observations of HH46~IRS and its outflow. Overview and first results B. Nisini, M. G. Navarro, T. Giannini, S. Antoniucci, P. J. Kavanagh, P. Hartigan, F. Bacciotti, A. Caratti o Garatti, A. Noriega Crespo, E. van Dishoek, E. Whelan, H. G. Arce, S. Cabrit, D. Coffey, D. Fedele, J. Eisloeffel, M. E. Palumbo, L. Podio, T. P. Ray, M. Schultze, R. G. Urso, J. M. Alcala’, M. A. Bautista, C. Codella, T. G. Greene, C. F. Manara arXiv:2404.06878v1 Announce Type: new Abstract: We present the first results of the JWST program PROJECT-J (PROtostellar JEts Cradle Tested with JWST ), designed to study the ClassRead More →

Correlation Functions of Photospheric Magnetic Fields in Solar Active Regions Valentina Abramenko, Regina Suleymanova arXiv:2404.06879v1 Announce Type: new Abstract: We used magnetograms acquired with the {it Helioseismic and Magnetic Imager} (HMI) on board the {it Solar Dynamics Observatory} (SDO) to calculate and analyze spatial correlation functions and the multi-fractal spectra in solar active regions (ARs). The analysis was performed for two very different types of ARs: i) simple bipolar magnetic structures with regular orientation (the magneto-morphological class A1), and ii) very complex multi-polar ARs (the magneto-morphological class B3). All ARs were explored at the developed phase during flareless periods. For correlation functions, the power-law andRead More →

A Multi-wavelength Study on A Gamma-ray Bright AGN 1308+326 Using KVN at 22 and 43 GHz Shan Li, Sang-sung Lee, Whee Yeon Cheong arXiv:2404.06882v1 Announce Type: new Abstract: In this paper, we conduct a multi-frequency analysis of the gamma-ray bright blazar 1308+326 from February 2013 to March 2020, using the Korean VLBI Network at 22 and 43 GHz and gamma-ray data from the Fermi Large Area Telescope (LAT). Our findings reveal spectral variations around the 2014 gamma-ray flare, aligning with the shock-in-jet model. A strong correlation is observed between gamma-ray and 43 GHz emissions, with a 27-day lag in the VLBI core light curve, indicatingRead More →

Impact of reflection Comptonization on X-ray reflection spectroscopy: the case of EXO 1846-031 Songcheng Li, Honghui Liu, Cosimo Bambi, James F. Steiner, Zuobin Zhang arXiv:2404.06893v1 Announce Type: new Abstract: Within the disk-corona model, it is natural to expect that a fraction of reflection photons from the disk are Compton scattered by the hot corona (reflection Comptonization), even if this effect is usually ignored in X-ray reflection spectroscopy studies. We study the effect by using NICER and NuSTAR data of the Galactic black hole EXO 1846-031 in the hard-intermediate state with the model SIMPLCUTX. Our analysis suggests that a scattered fraction of order 10% is requiredRead More →

Precession and Split of Tilted, Geometrically Thin Accretion Disk: an Analytical Study Ye Shen, Bin Chen arXiv:2404.06898v1 Announce Type: new Abstract: It has been observed that many relativistic jets display a kind of cork-screw-like precession. Numerical simulations has suggested that such kind of precession may originate from the precession of the disk. In this work, we introduce an analytical model to describe the precession and split of a tilted, geometrically thin disk. We consider the Lense-Thirring effect from the central (primary) black hole (BH) and the gravitational effect from the companion (secondary) BH far away from the center, both of which could induce the precessionRead More →

From MRI to SARI: Parametric survey of accretion disk instabilities Nicolas Brughmans, Rony Keppens, Hans Goedbloed arXiv:2404.06925v1 Announce Type: new Abstract: Accretion disks are highly unstable to magnetic instabilities driven by shear flow, where classically, the axisymmetric, weak-field Magneto-Rotational Instability (MRI) has received much attention through local WKB approximations. In contrast, discrete non-axisymmetric counterparts require a more involved analysis through a full global approach to deal with the influence of the nearby magnetohydrodynamic (MHD) continua. Recently, rigorous MHD spectroscopy identified a new type of an ultra-localised, non-axisymmetric instability in global disks with super-Alfv’enic flow. These Super-Alfv’enic Rotational Instabilities (SARIs) fill vast unstable regions in theRead More →

Gravitational Wave Memory Imprints on the CMB from Populations of Massive Black Hole Mergers Lorenz Zwick, David O’Neill, Kai Hendriks, Philip Kirkeberg, Miquel Miravet-Ten’es arXiv:2404.06927v1 Announce Type: new Abstract: Aims: To showcase and characterise the rich phenomenology of temperature fluctuation patterns that are imprinted on the CMB by the gravitational wave memory (GWM) of massive black hole (BH) mergers. Methods: We analyse both individual binaries as well as populations of binaries, distributed in local cosmological boxes at a given redshift. Results: The magnitude of the temperature fluctuations scales primarily as a function of binary total mass and pattern angular scale, and accumulates as a random-walkRead More →

The first spectroscopic IR reverberation programme on Mrk 509 J. A. J. Mitchell, M. J. Ward, D. Kynoch, J. V. Hern’andez Santisteban, K. Horne, J. -U. Pott, J. Esser, P. Mercatoris, C. Packham, G. J. Ferland, A. Lawrence, T. Fischer, A. J. Barth, C. Villforth, H. Winkler arXiv:2404.06930v1 Announce Type: new Abstract: Near IR spectroscopic reverberation of Active Galactic Nuclei (AGN) potentially allows the infrared (IR) broad line region (BLR) to be reverberated alongside the disc and dust continua, while the spectra can also reveal details of dust astro-chemistry. Here, we describe results of a short pilot study (17 near-IR spectra over a 183 dRead More →

Overcoming Confusion Noise with Hyperspectral Imaging from PRIMAger James M. S. Donnellan, Seb J. Oliver, Matthieu Bethermin, Longji Bing, Alberto Bolatto, Charles M. Bradford, Denis Burgarella, Laure Ciesla, Jason Glenn, Alexandra Pope, Stephen Serjeant, Raphael Shirley, JD T. Smith, Chris Sorrell arXiv:2404.06935v1 Announce Type: new Abstract: The PRobe far-Infrared Mission for Astrophysics (PRIMA) concept aims to perform mapping with spectral coverage and sensitivities inaccessible to previous FIR space telescopes. PRIMA’s imaging instrument, PRIMAger, provides unique hyperspectral imaging simultaneously covering 25-235 $mu$m. We synthesise images representing a deep, 1500 hr deg$^{-2}$ PRIMAger survey, with realistic instrumental and confusion noise. We demonstrate that we can construct cataloguesRead More →

Star-planet interaction and its impact on the stellar rotation Thiago M. Santiago, Sarah G. A. Barbosa, Francisco J. Cavalcante, Daniel B. de Freitas arXiv:2404.06958v1 Announce Type: new Abstract: The stellar rotation has an essential role in modifying the structure of the star and, therefore, the way these different interplays arise. On the other hand, changes in orbits impact the star’s rotation and its evolution. The evolution of the star’s rotation accounts for the angular momentum exchange with the planet and follows the effects of the internal transport of angular momentum and metallicity. Several models in the literature have aimed to find a theoretical way toRead More →

Ensemble power spectral density of SDSS quasars in UV/optical bands Vincenzo Petrecca, Iossif Papadakis, Maurizio Paolillo, Demetra De Cicco, Franz Bauer arXiv:2404.06983v1 Announce Type: new Abstract: Context: Quasar variability has proven to be a powerful tool to constrain the properties of their inner engine and the accretion process onto supermassive black holes. Correlations between UV/optical variability and physical properties have been long studied with a plethora of different approaches and time-domain surveys, although the detailed picture is not yet clear. Aims: We analysed archival data from the SDSS Stripe-82 region to study how the quasar power spectral density (PSD) depends on the black hole mass,Read More →

New Parameters for Star Cluster Dynamics: the role of clusters initial conditions Bhavana Bhat, Barbara Lanzoni, Enrico Vesperini, Francesco R. Ferraro, Francisco I. Aros, Abbas Askar, Arkadiusz Hypki arXiv:2404.06992v1 Announce Type: new Abstract: We recently introduced three new parameters that describe the shape of the normalized cumulative radial distribution (nCRD) of the innermost stars in globular clusters and trace the clusters dynamical evolution. Here we extend our previous investigations to the case of a large set of Monte Carlo simulations of globular clusters, started from a broad range of initial conditions. All the models are analyzed at the same age of 13 Gyr, when theyRead More →