RAS_WEB (Page 2)

AGN-driven outflows in clumpy media: multiphase structure and scaling relations Samuel Ruthven Ward, Tiago Costa, Chris M. Harrison, Vincenzo Mainieri arXiv:2407.17593v1 Announce Type: new Abstract: Small-scale winds driven from accretion discs surrounding active galactic nuclei (AGN) are expected to launch kpc-scale outflows into their host galaxies. However, the ways in which the structure of the interstellar medium (ISM) affects the multiphase content and impact of the outflow remains uncertain. We present a series of numerical experiments featuring a realistic small-scale AGN wind with velocity $5times 10^3-10^4 rm{km/s}$ interacting with an isolated galaxy disc with a manually-controlled clumpy ISM, followed at sub-pc resolution. Our simulations areRead More →

Solar rotation and activity for cycle 24 from SDO/AIA observations Zahra Shokri, Nasibe Alipour, Hossein Safari arXiv:2407.17594v1 Announce Type: new Abstract: The differential rotation plays a crucial role in the dynamics of the Sun. We study the solar rotation and its correlation with solar activity by applying a modified machine learning algorithm to identify and track coronal bright points (CBPs) from the Solar Dynamics Observatory/Atmospheric Imaging Assembly observations at 193 AA during cycle 24. For more than 321,440 CBPs, the sidereal and meridional velocities are computed. We find the occurring height of CBPs about 5627 km above the photosphere. We obtain a rotational map forRead More →

Suppressed Cosmic Ray Energy Densities in Molecular Clouds From Streaming Instability-Regulated Transport Margot Fitz Axen, Stella Offner, Phillip F. Hopkins, Mark R. Krumholz, Michael Y. Grudic arXiv:2407.17597v1 Announce Type: new Abstract: Cosmic rays (CRs) are the primary driver of ionization in star forming molecular clouds (MCs). Despite their potential impacts on gas dynamics and chemistry, no simulations of star cluster formation following the creation of individual stars have included explicit cosmic ray transport (CRT) to date. We conduct the first numerical simulations following the collapse of a $2000 M_{odot}$ MC and the subsequent star formation including CRT using the STARFORGE framework implemented in the GIZMORead More →

Unexplained correlation between the Cosmic Microwave Background temperature and the local matter density distribution M. Cruz, E. Mart’inez-Gonz’alez, C. Gimeno-Amo, B. J. Kavanagh, M. Tucci arXiv:2407.17599v1 Announce Type: new Abstract: Recent observations have indicated a Cosmic Microwave Background (CMB) temperature decrement in the direction of local galaxies within the 2MASS Redshift Survey. We investigate this detection by analyzing its frequency dependence and sensitivity to component separation methods, suggesting that Galactic foregrounds are unlikely to be the cause. Contrary to previous studies, we find that the decrement is independent of galaxy type, indicating a possible correlation between the CMB and the overall matter density field. ToRead More →

Climate Transition to Temperate Nightside at High Atmosphere Mass Evelyn Macdonald, Kristen Menou, Christopher Lee, Adiv Paradise arXiv:2407.17600v1 Announce Type: new Abstract: Our recent work shows how M-Earth climates and transmission spectra depend on the amount of ice-free ocean on the planet’s dayside and the mass of N2 in its atmosphere. M-Earths with more ice-free ocean and thicker atmospheres are hotter and more humid, and have larger water vapour features in their transmission spectra. In this paper, we describe a climate transition in high-pN2 simulations from the traditional “eyeball” M-Earth climate, in which only the substellar region is temperate, to a “temperate nightside” regime inRead More →

Multi-layer anti-reflection coats using ePTFE membrane for mm-wavelength plastic optics Miranda Eiben, Keara Carter, Marion Dierickx, Brodi Elwood, Paul Grimes, John Kovac, Matthew Miller, Matthew A. Petroff, Annie Polish, Clara Verg`es arXiv:2407.17604v1 Announce Type: new Abstract: Future millimeter wavelength experiments aim to both increase aperture diameters and broaden bandwidths to increase the sensitivity of the receivers. These changes produce a challenging anti-reflection (AR) design problem for refracting and transmissive optics. The higher frequency plastic optics require consistently thin polymer coats across a wide area, while wider bandwidths require multilayer designs. We present multilayer AR coats for plastic optics of the high frequency BICEP Array receiverRead More →

Infrared Colors of Small Serendipitously-Found Asteroids in the UKIRT Hemisphere Survey Samantha G. Morrison (Grinnell College, Northern Arizona University), Ryder H. Strauss (Northern Arizona University), David E. Trilling (Northern Arizona University), Andy J. L’opez-Oquendo (Northern Arizona University), Justice Bruursema (United States Naval Observatory – Flagstaff, AZ), Frederick J. Vrba (United States Naval Observatory – Flagstaff, AZ) arXiv:2407.17613v1 Announce Type: new Abstract: The UKIRT Hemisphere Survey covers the northern sky in the infrared from 0-60 degrees declination. Current data releases include both J and K bands, with H-band data forthcoming. Here we present a novel pipeline to recover asteroids from this survey data. We recover 26,138Read More →

Ephemeris Reconstruction for Comet 67P/Churyumov-Gerasimenko During Rosetta Proximity Phase from Radiometric Data Analysis Riccardo Lasagni Manghi, Marco Zannoni, Paolo Tortora, Frank Budnik, Bernard Godard, Nicholas Attree arXiv:2407.17615v1 Announce Type: new Abstract: This study provides a continuous ephemeris reconstruction for comet 67P/Churyumov-Gerasimenko by reanalyzing Rosetta radiometric measurements and Earth-based astrometry. Given the comet-to-spacecraft relative trajectory provided by the navigation team, these measurements were used to estimate the comet state and some critical physical parameters, most notably the non-gravitational accelerations induced by the outgassing of surface volatiles, for which different models were tested and compared. The reference reconstructed ephemeris, which uses a stochastic acceleration model, has positionRead More →

Hydrogen-Atmosphere White Dwarfs Are Less Likely To Be Found with Wide-Binary Companions Jeremy Heyl arXiv:2407.17634v1 Announce Type: new Abstract: The fraction of white dwarfs found in wide binaries is estimated by cross referencing a catalogue of wide binaries with catalogues photometrically determined white-dwarf candidates and spectroscopically confirmed white dwarf stars. The wide-binary fraction of white dwarfs with hydrogen-dominated atmospheres is about 5%, but the fraction of white dwarfs with helium or carbon-dominated atmospheres is significantly larger. Using spectroscopic classifications, the binary fraction of DA white dwarfs is determined to be $0.063pm0.002$ and for non-DA white dwarfs is larger at $0.080pm0.004$.arXiv:2407.17634v1 Announce Type: new Abstract: TheRead More →

Atmospheric parameters and chemical abundances within 100 pc. A sample of G, K, and M main-sequence stars Ricardo L’opez-Valdivia, Luc’ia Adame, Eduardo Zagala Lagunas, Carlos G. Rom’an-Z’u~niga, Jes’us Hern’andez, Edilberto S’anchez, Jos’e G. Fern’andez-Trincado, Leticia Carigi, Marina Kounkel, Richard R. Lane, Keivan G. Stassun, Sandro Villanova arXiv:2407.17640v1 Announce Type: new Abstract: To date, we have access to enormous inventories of stellar spectra that allow the extraction of atmospheric parameters and chemical abundances essential in stellar studies. However, characterizing such a large amount of data is complex and requires a good understanding of the studied object to ensure reliable and homogeneous results. In this study, weRead More →

ACACIAS I: Element abundance labels for 192 stars in the dwarf galaxy NGC 6822 Melissa K. Ness, J. Trevor Mendel, Sven Buder, Adam Wheeler, Alexander P. Ji, Luka Mijnarends, Kim Venn, Else Starkenburg, Ryan Leaman, Kathryn Grasha, Sarah Aquilina arXiv:2407.17661v1 Announce Type: new Abstract: The element abundances of local group galaxies connect enrichment mechanisms to galactic properties and serve to contextualise the Milky Way’s abundance distributions. Individual stellar spectra in nearby galaxies can be extracted from Integral Field Unit (IFU) data, and provide a means to take an abundance census of the local group. We introduce a program that leverages $R=1800$, $mathrm{SNR}=15$, IFU resolved spectraRead More →

Tackling the Problem of Distributional Shifts: Correcting Misspecified, High-Dimensional Data-Driven Priors for Inverse Problems Gabriel Missael Barco, Alexandre Adam, Connor Stone, Yashar Hezaveh, Laurence Perreault-Levasseur arXiv:2407.17667v1 Announce Type: new Abstract: Bayesian inference for inverse problems hinges critically on the choice of priors. In the absence of specific prior information, population-level distributions can serve as effective priors for parameters of interest. With the advent of machine learning, the use of data-driven population-level distributions (encoded, e.g., in a trained deep neural network) as priors is emerging as an appealing alternative to simple parametric priors in a variety of inverse problems. However, in many astrophysical applications, it isRead More →

WASP 0346-21: An EL CVn-Type Eclipsing Binary with Multiperiodic Pulsations in a Triple System Jae Woo Lee, Kyeongsoo Hong, Min-Ji Jeong, Marek Wolf arXiv:2407.17729v1 Announce Type: new Abstract: VLT/UVES spectroscopic and TESS photometric observations for WASP 0346-21 allow the direct determination of its physical properties, along with the detection of a circumbinary object and oscillating signals. The high-resolution spectra yielded the radial velocities of all three stars and the atmospheric parameters of $T_{rm eff,A}$ = 7225$pm42$ K, [M/H] = 0.30$pm$0.03 dex, and $v_{rm A}$$sin i$ = 78$pm$5 km s$^{-1}$ of the primary component. The combined analysis of these observations resulted in the fundamental parameters ofRead More →

Observational Evidence for Magnetic Field Amplification in SN 1006 Moeri Tao, Jun Kataoka, Takaaki Tanaka arXiv:2407.17739v1 Announce Type: new Abstract: We report the first observational evidence for magnetic field amplification in the north-east/south-west (NE/SW) shells of supernova remnant SN 1006, one of the most promising sites of cosmic ray (CR) acceleration. In previous studies, the strength of magnetic fields in these shells was estimated to be $B_{rm SED}$ $simeq$ 25$mu$G from the spectral energy distribution, where the synchrotron emission from relativistic electrons accounted for radio to X-rays, along with the inverse Compton emission extending from the GeV to TeV energy bands. However, the analysis ofRead More →

The GLINT nulling interferometer: improving nulls for high-contrast imaging Eckhart Spalding, Elizabeth Arcadi, Glen Douglass, Simon Gross, Olivier Guyon, Marc-Antoine Martinod, Barnaby Norris, Stephanie Rossini-Bryson, Adam Taras, Peter Tuthill, Kyohoon Ahn, Vincent Deo, Mona El Morsy, Julien Lozi, Sebastien Vievard, Michael Withford arXiv:2407.17741v1 Announce Type: new Abstract: GLINT is a nulling interferometer downstream of the SCExAO extreme-adaptive-optics system at the Subaru Telescope (Hawaii, USA), and is a pathfinder instrument for high-contrast imaging of circumstellar environments with photonic technologies. GLINT is effectively a testbed for more stable, compact, and modular instruments for the era of 30m-class telescopes. GLINT is now undergoing an upgrade with a newRead More →

Identifying pulsar candidates in interferometric radio images using scintillation Jitendra Salal, Shriharsh P. Tendulkar, Visweshwar Ram Marthi arXiv:2407.17764v1 Announce Type: new Abstract: Pulsars have been primarily detected by their narrow pulses or periodicity in time domain data. Interferometric surveys for pulsars are challenging due to the trade-off between beam sensitivity and beam size and the corresponding tradeoff between survey sensitivity (depth), sky coverage, and computational efforts. The detection sensitivity of time-domain searches for pulsars is affected by dispersion smearing, scattering, and rapid orbital motion of pulsars in binaries. We have developed a new technique to select pulsar candidates in interferometric radio images by identifying scintillatingRead More →

High resolution X-ray spectra of the compact binary supersoft X-ray source CAL 87 Songpeng Pei, Xiaowan Zhang, Qiang Li, Ziwei Ou arXiv:2407.17778v1 Announce Type: new Abstract: In this study, we present an analysis of the archival X-ray data of the eclipsing supersoft X-ray binary CAL 87 observed with the {it Chandra} Advanced CCD Imaging Spectrometer (ACIS) camera and Low Energy Transmission Grating (LETG) in 2001 August and with {it XMM-Newton} in 2003 April. The high resolution X-ray spectra are almost unchanged in the two different dates. The average unabsorbed X-ray luminosity during the exposure was 4.64$-$5.46$times10^{36}$ ergs s$^{-1}$ in 2001 and 4.54$-$4.82 $times10^{36}$ ergs s$^{-1}$Read More →

TOI-1408: Discovery and Photodynamical Modeling of a Small Inner Companion to a Hot Jupiter Revealed by TTVs Judith Korth, Priyanka Chaturvedi, Hannu Parviainen, Ilaria Carleo, Michael Endl, Eike W. Guenther, Grzegorz Nowak, Carina Persson, Phillip J. MacQueen, Alexander J. Mustill, Juan Cabrera, William D. Cochran, Jorge Lillo-Box, David Hobbs, Felipe Murgas, Michael Greklek-McKeon, Hanna Kellermann, Guillaume H’ebrard, Akihiko Fukui, Enric Pall’e, Jon M. Jenkins, Joseph D. Twicken, Karen A. Collins, Samuel N. Quinn, J’an v{S}ubjak, Paul G. Beck, Davide Gandolfi, Savita Mathur, Hans J. Deeg, David W. Latham, Simon Albrecht, David Barrado, Isabelle Boisse, Herv’e Bouy, Xavier Delfosse, Olivier Demangeon, Rafael A. Garc’ia, Artie P.Read More →

Dissipative Quintessential Cosmic Inflation Kourosh Nozari, Fateme Rajabi, Narges Rashidi arXiv:2407.17808v1 Announce Type: new Abstract: In this paper we construct a dissipative quintessential cosmic inflation. For this purpose, we add a multiplicative dissipative term in the standard quintessence field Lagrangian. We consider the specific form of dissipation as the time integral including the Hubble parameter and an arbitrary function that describes the dissipative properties of the quintessential scalar field. Inflation parameters and observables are calculated under slow-roll approximations and a detailed calculation of the cosmological perturbations is performed in this setup. We consider different forms of potentials and calculate the scalar spectral index and tensor-to-scalarRead More →

Tracing the evolution of the cool gas in CGM and IGM environments through Mg II absorption from redshift z=0.75 to z=1.65 using DESI-Y1 data X. Wu, Z. Cai, T. -W. Lan, S. Zou, A. Anand, Biprateep Dey, Z. Li, J. Aguilar, S. Ahlen, D. Brooks, T. Claybaugh, A. de la Macorra, P. Doel, S. Ferraro, J. E. Forero-Romero, S. Gontcho A Gontcho, K. Honscheid, S. Juneau, R. Kehoe, T. Kisner, A. Lambert, M. Landriau, L. Le Guillou, M. Manera, A. Meisner, R. Miquel, J. Moustakas, J. A. Newman, F. Prada, G. Rossi, E. Sanchez, D. Schlegel, M. Schubnell, M. Siudek, D. Sprayberry, G. Tarl’e, B.Read More →