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In: arXiv

Non-Monotonic Relations of Galaxy Star Formation, Radius, and Structure at Fixed Stellar Mass Jimena Stephenson, Aldo Rodriguez-Puebla, S. M. Faber, Joel R. Primack, Vladimir Avila-Reese, A. R. Calette, Carlo Cannarozzo, James Kakos, Mariana Cano-D’iaz, David C. Koo, Francesco Shankar, D. F. Morell arXiv:2404.10114v1 Announce Type: new Abstract: We investigate the relation between galaxy structure and star formation rate (SFR) in a sample of $sim2.9times10^{4}$ central galaxies with $z0.5$. The star-forming main sequence (SFMS) shows a bend around the stellar mass of $M_astleq{}M_c=2times10^{10}{}M_{odot}$. At $M_astleq{}M_c$ the SFMS follows a power-law $text{SFR}propto{}M_ast^{0.85}$, while at higher masses it flattens. $M_c$ corresponds to a dark matter halo mass ofRead More →

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In: arXiv

Using ZDI maps to determine magnetic forces and torques at the photospheres of Early-type stars James MacDonald, Tali Natan, V’eronique Petit, Oleg Kochukhov, Matthew E. Shultz arXiv:2404.10161v1 Announce Type: new Abstract: We use the magnetic field components measured by Zeeman Doppler imaging (ZDI) to calculate the stellar surface force and torque due to magnetic stresses for the fast rotators $sigma$ Ori E, 36 Lyn and CU Vir, and the slow rotator $tau$ Sco. If we assume the stars have spherical photospheres, the estimated torques give spin down time scales no larger than $7 times 10^5$ yr. For $sigma$ Ori E, the predicted spin down timeRead More →

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In: arXiv

A magnetic massive star has experienced a stellar merger A. J. Frost, H. Sana, L. Mahy, G. Wade, J. Barron, J. -B. Le Bouquin, A. M’erand, F. R. N. Schneider, T. Shenar, R. H. Barb’a, D. M. Bowman, M. Fabry, A. Farhang, P. Marchant, N. I. Morrell, J. V. Smoker arXiv:2404.10167v1 Announce Type: new Abstract: Massive stars (those larger than 8 solar masses at formation) have radiative envelopes that cannot sustain a dynamo, the mechanism that produces magnetic fields in lower-mass stars. Despite this, approximately 7% of massive stars have observed magnetic fields, the origin of which is debated. We used multi-epoch interferometric and spectroscopicRead More →

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In: arXiv

Four Changing-Look Active Galactic Nuclei Found From Optical Variations Litao Zhu, Jie Li, Zhongxiang Wang, Jujia Zhang arXiv:2404.10181v1 Announce Type: new Abstract: We report the finding of four changing-look (CL) active galactic nuclei (AGN). We selected these sources due to their potential as interesting targets when considering their relatively-large optical flux variations and related mid-infrared flux variations. To identify their CL feature, we use archival spectra from the Sloan Digital Sky Survey (SDSS) taken at least 8 years ago as well as spectra taken recently from the Transient Name Server (TNS) and with the 2.4-m LiJiang telescope (LJT). We study the sources’ spectral changes byRead More →

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In: arXiv

Testing the TDE Outflow Model for the Bipolar Sgr A Lobes at the Galactic Center Sida Li, Fulai Guo arXiv:2404.10205v1 Announce Type: new Abstract: Sgr A lobes are a pair of 15-pc-sized bipolar bubbles with co-aligned major axes perpendicular to the Galactic plane found in X-ray and radio observations of the Galactic center (GC). Their elusive origin is a vital ingredient in understanding the ongoing high energy processes at the GC. Here we perform a suite of hydrodynamic simulations to explore the tidal disruption event (TDE) outflow model for the origin of the Sgr A lobes. By following the outflow evolution in the circumnuclear medium,Read More →

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In: arXiv

Protoplanetary Disk Polarization at Multiple Wavelengths: Are Dust Populations Diverse? Rachel E. Harrison, Zhe-Yu Daniel Lin, Leslie W. Looney, Zhi-Yun Li, Haifeng Yang, Ian Stephens, Manuel Fern’andez-L’opez arXiv:2404.10217v1 Announce Type: new Abstract: Millimeter and sub-millimeter observations of continuum linear dust polarization provide insight into dust grain growth in protoplanetary disks, which are the progenitors of planetary systems. We present the results of the first survey of dust polarization in protoplanetary disks at 870 $mu$m and 3 mm. We find that protoplanetary disks in the same molecular cloud at similar evolutionary stages can exhibit different correlations between observing wavelength and polarization morphology and fraction. We exploreRead More →

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In: arXiv

Quasars with Flare/Eclipse-like Variability Identified in ZTF Zhiyuan Zheng, Yong Shi, Shuowen Jin, H. Dannerbauer, Qiusheng Gu, Xin Li, Xiaoling Yu arXiv:2404.10245v1 Announce Type: new Abstract: Active galactic nuclei (AGNs) are known to exhibit optical/UV variability and most of them can be well modeled by the damped random walks. Physical processes that are not related to the accretion disk, such as tidal disruption events (TDE) or moving foreground dusty clouds, can cause flare-like and eclipse-like features in the optical light curve. Both long-term and high-cadence monitoring are needed to identify such features. By combining the Sloan Digital Sky Survey (SDSS), Panoramic Survey Telescope, and RapidRead More →

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In: arXiv

A 25-micron single photon sensitive kinetic inductance detector Peter K. Day, Nicholas F. Cothard, Christopher Albert, Logan Foote, Elijah Kane, Byeong H. Eom, Ritoban Basu Thakur, Reinier M. J. Janssen, Andrew Beyer, Pierre Echternach, Sven van Berkel, Steven Hailey-Dunsheath, Thomas R. Stevenson, Shahab Dabironezare, Jochem J. A. Baselmans, Jason Glenn, C. Matt Bradford, Henry G. Leduc arXiv:2404.10246v1 Announce Type: new Abstract: We report measurements characterizing the performance of a kinetic inductance detector array designed for a wavelength of 25 microns and very low optical background level suitable for applications such as a far-infrared instrument on a cryogenically cooled space telescope. In a pulse counting modeRead More →

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In: arXiv

The Thousand-Pulsar-Array programme on MeerKAT XIV: On the high linearly polarized pulsar signals Simon Johnston, Dipanjan Mitra, Michael Keith, Lucy Oswald, Aris Karastergiou arXiv:2404.10254v1 Announce Type: new Abstract: The S-shaped swing of the linear polarization position angle (PPA) observed in many pulsars can be interpreted by the rotating vector model (RVM). However, efforts to fit the RVM for a large sample of pulsars observed with the MeerKAT telescope as a part of the Thousand-Pulsar-Array (TPA) programme, only succeeded for about half the cases. High time-resolution studies suggest that the failed cases arise due to the presence of orthogonal polarization modes, or highly disordered distribution ofRead More →

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In: arXiv

Dynamical Model of Rotation and Orbital Coupling for Deimos Kai Huang, Lijun Zhang, Yongzhang Yang, Mao Ye, Yuqiang Li arXiv:2404.10257v1 Announce Type: new Abstract: This paper introduces a novel dynamical model, building upon the existing dynamical model for Deimos in the current numerical ephemerides, which only encompasses the simple libration effects of Deimos. The study comprehensively incorporates the rotational dynamics of Deimos influenced by the torque exerted by the major celestial bodies (Mars, the Sun) in the solar system within the inertial space. Consequently, a full dynamical model is formulated to account for the complete coupling between the rotation and orbit of Deimos. Simultaneously, employingRead More →

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In: arXiv

Study of the Balmer decrements for Galactic classical Be stars using the Himalayan Chandra Telescope of India Gourav Banerjee, Blesson Mathew, Suman Bhattacharyya, Ashish Devaraj, Sreeja S Kartha, Santosh Joshi arXiv:2404.10339v1 Announce Type: new Abstract: In a recent study, Banerjee et al. (2021) produced an atlas of all major emission lines found in a large sample of 115 Galactic field Be stars using the 2-m Himalayan Chandra Telescope (HCT) facility located at Ladakh, India. This paper presents our further exploration of these stars to estimate the electron density in their discs. Our study using Balmer decrement values indicate that their discs are generally optically thickRead More →

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In: arXiv

Self-similarity of the magnetic field at different scales: the case of G31.41+0.31 M. T. Beltr’an (INAF-Osservatorio Astrofisico di Arcetri), M. Padovani (INAF-Osservatorio Astrofisico di Arcetri), D. Galli (INAF-Osservatorio Astrofisico di Arcetri), N. ‘A~nez-L’opez (Universit’e Paris-Saclay), J. M. Girart (Institut de Ci`encies de l’Espai), R. Cesaroni (INAF-Osservatorio Astrofisico di Arcetri), D. Dall’Olio (Chalmers University of Technology), G. Anglada (Instituto de Astrof’isica de Andaluc’ia), C. Y. Law (Chalmers University of Technology), A. Lorenzani (INAF-Osservatorio Astrofisico di Arcetri), L. Moscadelli (INAF-Osservatorio Astrofisico di Arcetri), ‘A. S’anchez-Monge (Institut de Ci`encies de l’Espai), M. Osorio (Instituto de Astrof’isica de Andaluc’ia), Q. Zhang (Center for Astrophysics | Harvard & Smithsonian) arXiv:2404.10347v1Read More →

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In: arXiv

Effect of Systematic Uncertainties on Density and Temperature Estimates in Coronae of Capella Xixi Yu, Vinay L. Kashyap, Giulio Del Zanna, David A. van Dyk, David C. Stenning, Connor P. Ballance, Harry P. Warren arXiv:2404.10427v1 Announce Type: new Abstract: We estimate the coronal density of Capella using the O VII and Fe XVII line systems in the soft X-ray regime that have been observed over the course of the Chandra mission. Our analysis combines measures of error due to uncertainty in the underlying atomic data with statistical errors in the Chandra data to derive meaningful overall uncertainties on the plasma density of the coronae ofRead More →

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In: arXiv

The evolutionary pathways of disk galaxies with different sizes Hong-Chuan Ma, Min Du, Luis C. Ho, Ming-jie Sheng, Shihong Liao arXiv:2404.10432v1 Announce Type: new Abstract: From the IllustrisTNG-50 simulation, a sample of 836 central disk galaxies with tiny stellar halos is chosen to study the inherent evolution of galaxies driven by nature. These galaxies are classified as compact, normal, or extended by referencing their locations on the mass-size ($M_star-R_{rm 1/2}$) diagram. This research demonstrates the distinctive evolutionary pathways of galaxies with different sizes in IllustrisTNG simulations, primarily driven by nature. It is confirmed that disk galaxies inherit the angular momentum of their parent dark matterRead More →

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In: arXiv

High-resolution atmospheric retrievals of WASP-76b transmission spectroscopy with ESPRESSO: Monitoring limb asymmetries across multiple transits Cathal Maguire, Neale P. Gibson, Stevanus K. Nugroho, Mark Fortune, Swaetha Ramkumar, Siddharth Gandhi, Ernst de Mooij arXiv:2404.10463v1 Announce Type: new Abstract: Direct atmospheric retrievals of exoplanets at high-resolution have recently allowed for a more detailed characterisation of their chemistry and dynamics from the ground. By monitoring the longitudinal distribution of species, as well as the varying vertical temperature structure and dynamics between the limbs of WASP-76b, across multiple transits, we aim to enhance our understanding of the 3D nature and chemical/dynamical evolution of such objects over the timescales ofRead More →

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In: arXiv

Membership determination in open clusters using the DBSCAN Clustering Algorithm Mudasir Raja, Priya Hasan, Md Mahmudunnobe, Md Saifuddin, S N Hasan arXiv:2404.10477v1 Announce Type: new Abstract: In this paper, we apply the machine learning clustering algorithm Density Based Spatial Clustering of Applications with Noise (DBSCAN) to study the membership of stars in twelve open clusters (NGC~2264, NGC~2682, NGC~2244, NGC~3293, NGC~6913, NGC~7142, IC~1805, NGC~6231, NGC~2243, NGC 6451, NGC 6005 and NGC 6583) based on Gaia DR3 Data. This sample of clusters spans a variety of parameters like age, metallicity, distance, extinction and a wide parameter space in proper motions and parallaxes. We obtain reliable cluster membersRead More →

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In: arXiv

In-depth analysis of solar models with high-metallicity abundances and updated opacity tables G. Buldgen, A. Noels, R. Scuflaire, A. M. Amarsi, N. Grevesse, P. Eggenberger, J. Colgan, C. J. Fontes, V. A. Baturin, A. V. Oreshina, S. V. Ayukov, P. Hakel, D. P. Kilcrease arXiv:2404.10478v1 Announce Type: new Abstract: Due to the high quality constraints available for the Sun, we can carry out combined analyses using neutrino, spectroscopic and helioseismic observations. Such studies lay the ground for future improvements of key physical components of solar and stellar models, such as the equation of state, radiative opacities or prescriptions for macroscopic transport processes of chemicals whichRead More →

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In: arXiv

Discovery of a dormant 33 solar-mass black hole in pre-release Gaia astrometry Gaia Collaboration, P. Panuzzo, T. Mazeh, F. Arenou, B. Holl, E. Caffau, A. Jorissen, C. Babusiaux, P. Gavras, J. Sahlmann, U. Bastian, {L}. Wyrzykowski, L. Eyer, N. Leclerc, N. Bauchet, A. Bombrun, N. Mowlavi, G. M. Seabroke, D. Teyssier, E. Balbinot, A. Helmi, A. G. A. Brown, A. Vallenari, T. Prusti, J. H. J. de Bruijne, A. Barbier, M. Biermann, O. L. Creevey, C. Ducourant, D. W. Evans, R. Guerra, A. Hutton, C. Jordi, S. A. Klioner, U. Lammers, L. Lindegren, X. Luri, F. Mignard, C. Nicolas, S. Randich, P. Sartoretti, R. Smiljanic,Read More →

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In: arXiv

Early-time gamma-ray constraints on cosmic-ray acceleration in the core-collapse SN 2023ixf with the Fermi Large Area Telescope G. Mart’i-Devesa, C. C. Cheung, N. Di Lalla, M. Renaud, G. Principe, N. Omodei, F. Acero arXiv:2404.10487v1 Announce Type: new Abstract: While SNRs have been considered the most relevant Galactic CR accelerators for decades, CCSNe could accelerate particles during the earliest stages of their evolution and hence contribute to the CR energy budget in the Galaxy. Some SNRs have indeed been associated with TeV gamma-rays, yet proton acceleration efficiency during the early stages of an SN expansion remains mostly unconstrained. The multi-wavelength observation of SN 2023ixf, a TypeRead More →

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In: arXiv

Representations of Noisy $N$-Ports Martin Bucher (Universit’e Paris Cit’e/CNRS), Daniel Molnar (University of Cambridge) arXiv:2404.10502v1 Announce Type: new Abstract: Much has been written about the representation of noisy linear 2-ports. Here we present a theory of noisy $N$-ports. We show how in the general case there are $(2N)!/(N!)^2$ equivalent representations and give the transformations relating them. We also discuss singular cases in which some of the transformations are not possible as well as how to measure the noise properties of an $N$-port. This work is motivated by the REACH experiment to observe the global 21 cm signal for which modelling noise with exquisite precision isRead More →