RAS_WEB (Page 7)

Effect of the Large Magellanic Cloud on the kinematics of Milky Way satellites and virial mass estimate Andrey Kravtsov, Sophia Winney arXiv:2405.06017v1 Announce Type: new Abstract: We present a study illustrating the effects of the passage of a Large Magellanic Cloud (LMC) mass satellite on the distance and velocity distributions of satellites in $Lambda+$Cold Dark Matter simulations of Milky Way (MW) sized halos. In agreement with previous studies, we find that during such a passage the velocity distribution develops a high-velocity tail due to the reflex motion of the inner part of the halo, which can bias velocity-based virial halo mass estimates. When the velocityRead More →

Correcting for the overabundance of low-mass quiescent galaxies in semi-analytic models Jimi E. Harrold, Omar Almaini, Frazer R. Pearce, Robert M. Yates arXiv:2405.06018v1 Announce Type: new Abstract: We compare the L-Galaxies semi-analytic model to deep observational data from the UKIDSS Ultra Deep Survey (UDS) across the redshift range $0.5 arXiv:2405.06018v1 Announce Type: new Abstract: We compare the L-Galaxies semi-analytic model to deep observational data from the UKIDSS Ultra Deep Survey (UDS) across the redshift range $0.5Read More →

Wide post-common envelope binaries from Gaia: orbit validation and formation models Natsuko Yamaguchi, Kareem El-Badry, Natalie Rees, Sahar Shahaf, Tsevi Mazeh, Ren’e Andrae arXiv:2405.06020v1 Announce Type: new Abstract: Astrometry from {it Gaia} DR3 has enabled the discovery of a sample of 3000+ binaries containing white dwarfs (WD) and main-sequence (MS) stars in relatively wide orbits, with orbital periods $P_{rm orb} = (100-1000)$ d. This population was not predicted by binary population synthesis models before {it Gaia} and — if the {it Gaia} orbits are robust — likely requires very efficient envelope ejection during common envelope evolution (CEE). To assess the reliability of the {it Gaia}Read More →

Supernova Explosions of the Lowest-Mass Massive Star Progenitors Tianshu Wang, Adam Burrows arXiv:2405.06024v1 Announce Type: new Abstract: We here focus on the behavior of supernovae that technically explode in 1D (spherical symmetry). When simulated in 3D, however, the outcomes of representative progenitors of this class are quite different in almost all relevant quantities. In 3D, the explosion energies can be two to ten times higher, and there are correspondingly large differences in the $^{56}$Ni yields. These differences between the 3D and 1D simulations reflect in part the relative delay to explosion of the latter and in the former the presence of proto-neutron star convection thatRead More →

REBELS-25: Discovery of a dynamically cold disc galaxy at z = 7.31 Lucie E. Rowland, Jacqueline Hodge, Rychard Bouwens, Pavel Mancera Pi~na, Alexander Hygate, Hiddo Algera, Manuel Aravena, Rebecca Bowler, Elisabete da Cunha, Pratika Dayal, Andrea Ferrara, Thomas Herard-Demanche, Hanae Inami, Ivana van Leeuwen, Ilse de Looze, Pascal Oesch, Andrea Pallottini, Si^an Phillips, Matus Rybak, Sander Schouws, Renske Smit, Laura Sommovigo, Mauro Stefanon, Paul van der Werf arXiv:2405.06025v1 Announce Type: new Abstract: We present high resolution ($sim0.14$” = 710 pc) ALMA [CII] 158$mu$m and dust continuum follow-up observations of REBELS-25, a [CII]-luminous ($L_{mathrm{[CII]}}=(1.7pm0.2)times 10^9 mathrm{L_{odot}}$) galaxy at redshift $z=7.3065pm0.0001$. These high resolution, high signal-to-noise observationsRead More →

Microphysical Regulation of Non-Ideal MHD in Weakly-Ionized Systems: Does the Hall Effect Matter? Philip F. Hopkins, Jonathan Squire, Raphael Skalidis, Nadine H. Soliman arXiv:2405.06026v1 Announce Type: new Abstract: The magnetohydrodynamics (MHD) equations plus ‘non-ideal’ (Ohmic, Hall, ambipolar) resistivities are widely used to model weakly-ionized astrophysical systems. We show that if gradients in the magnetic field become too steep, the implied charge drift speeds become much faster than microphysical signal speeds, invalidating the assumptions used to derive both the resistivities and MHD equations themselves. Generically this situation will excite microscale instabilities that suppress the drift and current. We show this could be relevant at low ionizationRead More →

Investigating the {Origin} of the Absorption-Line Variability in Narrow-Line Seyfert 1 Galaxy WPVS 007 Kaylie S. Green (University of Western Ontario), Sarah C. Gallagher (University of Western Ontario), Karen M. Leighly (University of Oklahoma), Hyunseop Choi (University of Oklahoma), Dirk Grupe (Northern Kentucky University), Donald M. Terndrup (Ohio State University), Gordon T. Richards (Drexel University), S. Komossa (MPI fuer Radioastronomie) arXiv:2405.06027v1 Announce Type: new Abstract: Broad Absorption Line Quasars (BALQs) are actively accreting supermassive black holes that have strong outflows characterized by broad absorption lines in their rest-UV spectra. Variability in these absorption lines occurs over months to years depending on the source. WPVS 007,Read More →

Prospects of Detecting a Jet in Sagittarius A* with VLBI Erandi Chavez, Sara Issaoun, Michael D. Johnson, Paul Tiede, Christian Fromm, Yosuke Mizuno arXiv:2405.06029v1 Announce Type: new Abstract: Event Horizon Telescope (EHT) images of the horizon-scale emission around the Galactic Center supermassive black hole Sagittarius A* (Sgr A*) favor accretion flow models with a jet component. However, this jet has not been conclusively detected. Using the “best-bet” models of Sgr A* from the EHT collaboration, we assess whether this non-detection is expected for current facilities and explore the prospects of detecting a jet with VLBI at four frequencies: 86, 115, 230, and 345 GHz. WeRead More →

Binary black hole mergers from Population III star clusters Benedetta Mestichelli, Michela Mapelli, Stefano Torniamenti, Manuel Arca Sedda, Marica Branchesi, Guglielmo Costa, Giuliano Iorio, Filippo Santoliquido arXiv:2405.06037v1 Announce Type: new Abstract: Binary black holes (BBHs) born from the evolution of Population III (Pop. III) stars are one of the main high-redshift targets for next-generation ground-based gravitational-wave (GW) detectors. Their predicted initial mass function and lack of metals make them the ideal progenitors of black holes above the upper edge of the pair-instability mass gap, i.e. with a mass higher than $approx{}134$ (241) M$_odot$ for stars that become (do not become) chemically homogeneous during their evolution.Read More →

Sound training platform applied to astronomy Natasha Bertaina Lucero, Johanna Casado, Beatriz Garc’ia, Gonzalo Cayo arXiv:2405.06042v1 Announce Type: new Abstract: The convergence between astronomy and data sonification represents a significant advancement in the approach and analysis of cosmic information. By surpassing the visual exclusivity in data analysis in astronomy, innovative projects have developed software that goes beyond visual representation, transforming data into auditory and tactile displays. However, it has been evidenced that this novel technique requires specialized training, particularly for audio format data. This work describes the initial development of a platform aimed at providing training for data analysis in astronomy through sonification. The integrationRead More →

Euclid preparation. Sensitivity to neutrino parameters Euclid Collaboration, M. Archidiacono (Dipartimento di Fisica "Aldo Pontremoli", Universit`a degli Studi di Milano, Via Celoria 16, 20133 Milano, Italy, INFN-Sezione di Milano, Via Celoria 16, 20133 Milano, Italy), J. Lesgourgues (Institute for Theoretical Particle Physics and Cosmology), S. Casas (Institute for Theoretical Particle Physics and Cosmology), S. Pamuk (Institute for Theoretical Particle Physics and Cosmology), N. Sch"oneberg (Institut de Ci`encies del Cosmos), Z. Sakr (Institut f"ur Theoretische Physik, University of Heidelberg, Philosophenweg 16, 69120 Heidelberg, Germany, Institut de Recherche en Astrophysique et Plan’etologie, Universit’e St Joseph, Faculty of Sciences, Beirut, Lebanon), G. Parimbelli (Institute of Space Sciences, DipartimentoRead More →

Performance of the HAWC Observatory and TeV Gamma-Ray Measurements of the Crab Nebula with Improved Extensive Air Shower Reconstruction Algorithms A . Albert, R. Alfaro, C. Alvarez, A . Andr’es, J. C. Arteaga-Vel’azquez, D. Avila Rojas, H. A. Ayala Solares, R. Babu, E. Belmont-Moreno, K. S. Caballero-Mora, T. Capistr’an, A. Carrami~nana, S. Casanova, U. Cotti, J. Cotzomi, S. Couti~no de Le’on, E. De la Fuente, C. de Le’on, D. Depaoli, N. Di Lalla, R. Diaz Hernandez, B. L . Dingus, M. A. DuVernois, K. Engel, T. Ergin, C . Espinoza, K. L. Fan, K. Fang, N. Fraija, S. Fraija, J. A. Garc’ia-Gonz’alez, F. Garfias, HRead More →

Astrosat view of GX 339-4 during the peak of the recent outburst Shyam Prakash V. P., Ramadevi M. C., Vivek K. Agrawal arXiv:2405.06090v1 Announce Type: new Abstract: We present the spectral and timing analyses of textit{AstroSat} observations of the Black Hole X-ray Binary GX 339-4 when the source was close the peak of the outburst in 2024. We find that both the spectral and timing variability of the source is indicative of it in its steep power law (SPL) state during the observations. We used phenomenological and physical models to understand the physics and geometry of accretion during this spectral state of the source. SpectralRead More →

OzDES Reverberation Mapping Program: Stacking analysis with H$beta$, Mg II and C IV Umang Malik, Rob Sharp, A. Penton, Z. Yu, P. Martini, B. E. Tucker, T. M. Davis, G. F. Lewis, C. Lidman, M. Aguena, O. Alves, J. Annis, J. Asorey, D. Bacon, D. Brooks, A. Carnero Rosell, J. Carretero, T. -Y. Cheng, L. N. da Costa, M. E. S. Pereira, J. De Vicente, P. Doel, I. Ferrero, J. Frieman, G. Giannini, D. Gruen, R. A. Gruendl, S. R. Hinton, D. L. Hollowood, D. J. James, K. Kuehn, J. L. Marshall, J. Mena-Fern’andez, F. Menanteau, R. Miquel, R. L. C. Ogando, A. Palmese, A.Read More →

Detecting Moving Objects With Machine Learning Wesley C. Fraser (Herzberg Astronomy,Astrophysics Research Centre, National Research Council of Canada) arXiv:2405.06148v1 Announce Type: new Abstract: The scientific study of the Solar System’s minor bodies ultimately starts with a search for those bodies. This chapter presents a review of the use of machine learning techniques to find moving objects, both natural and artificial, in astronomical imagery. After a short review of the classical non-machine learning techniques that are historically used, I review the relatively nascent machine learning literature, which can broadly be summarized into three categories: streak detection, detection of moving point sources in image sequences, and detectionRead More →

Abundances in eight bulge stars from the optical and near-infrared Patr’icia da Silva, B. Barbuy, H. Ernandes, S. O. Souza, J. G. Fern’andez-Trincado, D. Gonz’alez-D’iaz arXiv:2405.06153v1 Announce Type: new Abstract: Context: The abundances of the $alpha$-elements are key for understanding the early chemical enrichment of the Galactic bulge. The elements of interest present lines in different wavelength regions, and some of them show lines only in part of the spectra. In the present work, the CNO trio, the alpha-elements Mg, Si, Ca, and Ti, and odd-Z Na and Al are examined as measured from optical and H-band lines. Aims: The aim of this work isRead More →

Multi-wavelength Emission of Gamma-ray Burst Prompt Phase. I. Time-resolved and Time-integrated Polarizations Jia-Sheng Li, Mi-Xiang Lan, Hao-Bing Wang arXiv:2405.06182v1 Announce Type: new Abstract: The time-integrated polarization degree (PD) at prompt optical band of gamma-ray burst (GRB) was predicted to be less than $20%$, while the time-resolved one can reach as high as $75%$ in photosphere model. Polarizations in optical band during GRB prompt phase had not been studied under framework of the magnetic reconnection model. Here, a three-segment power laws of the energy spectrum is used to reconstruct the Stokes parameters of the magnetic reconnection model. The multi-wavelength light curves and polarization curves from theRead More →

New comprehensive description of the scaling evolution of the cosmological magneto-hydrodynamic system Fumio Uchida, Motoko Fujiwara, Kohei Kamada, Jun’ichi Yokoyama arXiv:2405.06194v1 Announce Type: new Abstract: We study the evolution of primordial magnetic fields until the recombination epoch, which is constrained by the conservation of magnetic helicity density if they are maximally helical and by the Hosking integral if they are non-helical. We combine these constraints with conditions obtained by estimating time scales of energy dissipation processes to describe the evolution of magnetic field strength and magnetic coherence length analytically. The dissipation processes depend on whether magnetic or kinetic energy is dominant, whether the decay dynamicsRead More →

Toward a live homogeneous database of solar active regions based on SOHO/MDI and SDO/HMI synoptic magnetograms.II.parameters for solar cycle variability Ruihui Wang, Jie Jiang, Yukun Luo arXiv:2405.06224v1 Announce Type: new Abstract: Solar active regions (ARs) determine solar polar fields and cause solar cycle variability within the framework of the Babcock-Leighton (BL) dynamo. The contribution of an AR to the polar field is measured by its dipole field, which results from flux emergence and subsequent flux transport over the solar surface. The dipole fields contributed by an AR before and after the flux transport are referred to as the initial and final dipole fields, respectively. ForRead More →

New observational recipes for measuring dynamical state of galaxy clusters Hyowon Kim, Rory Smith, Jongwan Ko, Jong-Ho Shinn, Kyungwon Chun, Jihye Shin, Jaewon Yoo arXiv:2405.06245v1 Announce Type: new Abstract: During cluster assembly, a cluster’s virialization process leaves behind signatures that can provide information on its dynamical state. However, no clear consensus yet exists on the best way to achieve this. Therefore, we attempt to derive improved recipes for classifying the dynamical state of clusters in observations using cosmological simulations. Cluster halo mass and their subhalos’ mass are used to $ 10^{14}M_{odot} h^{-1}$ and $10^{10}M_{odot} h^{-1}$ to calculate five independent dynamical state indicators. We experiment withRead More →