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Researchers propose new formation model for massive hot subdwarfs In a new study published in the The Astrophysical Journal, Dr. Li Zhenwei and his collaborators from Yunnan Observatories of the Chinese Academy of Sciences (CAS), and Dr. Zhang Yangyang from the Zhoukou Normal University, proposed a new formation model for massive hot subdwarfs, offering explanations for a subset of helium-rich hot subdwarfs observed in the cosmos. phys.org Go to SourceRead More →

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Amazing Amateur Images of April 8th’s Total Solar Eclipse The last total solar eclipse across the Mexico, the U.S. and Canada for a generation wows observers. Did you see it? Last week’s total solar eclipse did not disappoint, as viewers from the Pacific coast of Mexico, across the U.S. from Texas to Maine and through the Canadian Maritime provinces were treated to an unforgettable show. The weather threw us all a curve-ball one week out, as favored sites in Texas and Mexico fought to see the event through broken clouds, while areas along the northeastern track from New Hampshire and Maine onward were actually treatedRead More →

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NASA observations find what helps heat roots of ‘moss’ on sun Did you know the sun has moss? Due to its resemblance to the earthly plants, scientists have named a small-scale, bright, patchy structure made of plasma in the solar atmosphere “moss.” This moss, which was first identified in 1999 by NASA’s TRACE mission, blossoms around the center of a sunspot group, where magnetic conditions are strong. It straddles two atmospheric layers known as the chromosphere and corona and hides below the long feathery ropes of plasma known as coronal loops. phys.org Go to SourceRead More →

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Astronomers discover the most metal-poor extreme helium star Using the Southern African Large Telescope (SALT), astronomers have performed high-resolution observations of a recently detected extreme helium star designated EC 19529–4430. It turned out that EC 19529–4430 is the most metal deficient among the population of known extreme helium stars. The finding was reported in a research paper published April 5 on the pre-print server arXiv. phys.org Go to SourceRead More →

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Can AI Understand Our Universe? Test of Fine-Tuning GPT by Astrophysical Data Yu Wang, Shu-Rui Zhang, Aidin Momtaz, Rahim Moradi, Fatemeh Rastegarnia, Narek Sahakyan, Soroush Shakeri, Liang Li arXiv:2404.10019v1 Announce Type: new Abstract: ChatGPT has been the most talked-about concept in recent months, captivating both professionals and the general public alike, and has sparked discussions about the changes that artificial intelligence (AI) will bring to the world. As physicists and astrophysicists, we are curious about if scientific data can be correctly analyzed by large language models (LLMs) and yield accurate physics. In this article, we fine-tune the generative pre-trained transformer (GPT) model by the astronomicalRead More →

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Catalog of variable stars in the WD 0009+501 and GRW +708247 fields based on photometric survey data on transiting exoplanets O. Ya. Yakovlev, A. F. Valeev, G. G. Valyavin, V. N. Aitov, G. Sh. Mitiani, T. A. Fatkhullin, G. M. Beskin, A. V. Tavrov, O. I. Korablev, G. A. Galazutdinov, V. V. Vlasyuk, E. V. Emelianov, V. V. Sasyuk, A. V. Perkov, S. F. Bondar, T. E. Burlakova, S. N. Fabrika, I. I. Romanyuk arXiv:2404.10027v1 Announce Type: new Abstract: We present a catalog of 150 variable stars, including 13 stars with exoplanet candidates. 37 stars were identified as variables for the first time. As aRead More →

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Late-time X-ray Observations of the Jetted Tidal Disruption Event AT2022cmc: The Relativistic Jet Shuts Off T. Eftekhari, A. Tchekhovskoy, K. D. Alexander, E. Berger, R. Chornock, T. Laskar, R. Margutti, Y. Yao, Y. Cendes, S. Gomez, A. Hajela, D. R. Pasham arXiv:2404.10036v1 Announce Type: new Abstract: The tidal disruption event (TDE) AT2022cmc represents the fourth known example of a relativistic jet produced by the tidal disruption of a stray star providing a unique probe of the formation and evolution of relativistic jets in otherwise dormant supermassive black holes (SMBHs). Here we present deep, late-time Chandra observations of AT2022cmc extending to $t_{rm obs} approx 400$ daysRead More →

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Dissecting the Interstellar Media of A Wolf-Rayet Galaxy at $z=2.76$ Takahiro Morishita, Massimo Stiavelli, Stefan Schuldt, Claudio Grillo arXiv:2404.10037v1 Announce Type: new Abstract: We report JWST/NIRSpec observations of a star-forming galaxy at $z=2.76$, MACSJ1149-WR1. We securely detect two temperature-sensitive auroral lines, [SIII]6312 (7.4$sigma$) and [OII]7320+7331 doublets (10$sigma$), and tentatively [NII]5755 ($2.3sigma$) for the first time in an individual galaxy at $z>1$. We perform a detailed analysis of its interstellar media (ISM), and derive electron temperatures, various heavy element abundances (O/H, N/O, S/O, and Ar/O) in the hot ionized region, and the neutral fraction in the warm ionized region. MACSJ1149-WR1 shows a broad feature at theRead More →

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Anatomy of an ionized bubble: NIRCam grism spectroscopy of the $z=6.6$ double-peaked Lyman-$alpha$ emitter COLA1 and its environment Alberto Torralba-Torregrosa, Jorryt Matthee, Rohan P. Naidu, Ruari Mackenzie, Gabriele Pezzulli, Anne Hutter, Pablo Arnalte-Mur, Siddhartha Gurung-L’opez, Sandro Tacchella, Pascal Oesch, Daichi Kashino, Charlie Conroy, David Sobral arXiv:2404.10040v1 Announce Type: new Abstract: The increasingly neutral intergalactic gas at $z>6$ impacts the Lyman-$alpha$ flux observed from galaxies. One luminous galaxy, COLA1, stands out because of its unique double-peaked Ly$alpha$ line at $z=6.6$, unseen in any simulation of reionization. Here we present JWST/NIRCam wide-field slitless spectroscopy in a 21 arcmin$^2$ field centered on COLA1. We find 141 galaxies spectroscopically-selectedRead More →

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Deep JWST/NIRCam imaging of Supernova 1987A Mikako Matsuura, M. Boyer, Richard G. Arendt, J. Larsson, C. Fransson, A. Rest, A. P. Ravi, S. Park, P. Cigan, T. Temim, E. Dwek, M. J. Barlow, P. Bouchet, G. Clayton, R. Chevalier, J. Danziger, J. De Buizer, I. De Looze, G. De Marchi, O. Fox, C. Gall, R. D. Gehrz, H. L. Gomez, R. Indebetouw, T. Kangas, F. Kirchschlager, R. Kirshner, P. Lundqvist, J. M. Marcaide, I. Mart’i-Vidal, M. Meixner, D. Milisavljevic, S. Orlando, M. Otsuka, F. Priestley, A. M. S. Richards, F. Schmidt, L. Staveley-Smith, Nathan Smith, J. Spyromilio, J. Vink, Lifan Wang, D. Watson, R. Wesson,Read More →

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Correlations among complex organic molecules around protostars: Effects of physical structure P. Nazari, B. Tabone, G. P. Rosotti, E. F. van Dishoeck arXiv:2404.10045v1 Announce Type: new Abstract: Column density ratios of complex organic molecules are generally constant across protostellar systems with some low-level scatter. However, the scatter in formamide (NH$_2$CHO) to methanol (CH$_3$OH) column density ratio is one of the highest. This larger scatter is sometimes interpreted as evidence of gas-phase formation of NH$_2$CHO. In this work we propose an alternative interpretation in which this scatter is produced by differences in the snowline locations related to differences in binding energies of these species and theRead More →

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Classifying binary black holes from Population III stars with the Einstein Telescope: a machine-learning approach Filippo Santoliquido, Ulyana Dupletsa, Jacopo Tissino, Marica Branchesi, Francesco Iacovelli, Giuliano Iorio, Michela Mapelli, Davide Gerosa, Jan Harms, Mario Pasquato arXiv:2404.10048v1 Announce Type: new Abstract: Third-generation (3G) gravitational-wave (GW) detectors like the Einstein Telescope (ET) will observe binary black hole (BBH) mergers at redshifts up to $zsim 100$. However, unequivocal determination of the origin of high-redshift sources will remain uncertain, due to the low signal-to-noise ratio (SNR) and poor estimate of their luminosity distance. This study proposes a machine learning approach to infer the origins of high-redshift BBHs, specifically differentiatingRead More →

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In: arXiv

Tilted Accretion Disks P. Chris Fragile, Matthew Liska arXiv:2404.10052v1 Announce Type: new Abstract: In this chapter, we review some of the interesting consequences that tilt between the spin axis of the black hole and angular momentum axis of the accretion disk can have on the dynamics, thermodynamics, and observational appearance of accreting systems, from precessing coronae and jets to standing nozzle shocks and quasi-periodic oscillations. We begin the chapter by examining some of the reasons tilted disks are interesting as well as present arguments for how ubiquitous they may be. We then review the existing simulation results in the literature, broadly dividing them into sectionsRead More →

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The Environmental Dependence of the Stellar Mass – Gas Metallicity Relation in Horizon Run 5 Aaron R. Rowntree, Ankit Singh, Fiorenzo Vincenzo, Brad K. Gibson, C’eline Gouin, Daniela Gal’arraga-Espinosa, Jaehyun Lee, Juhan Kim, Clotilde Laigle, Changbom Park, Christophe Pichon, Gareth Few, Sungwook E. Hong, Yongwhi Kim arXiv:2404.10055v1 Announce Type: new Abstract: Metallicity offers a unique window into the baryonic history of the cosmos, being instrumental in probing evolutionary processes in galaxies between different cosmic environments. We aim to quantify the contribution of these environments to the scatter in the mass-metallicity relation (MZR) of galaxies. By analysing the galaxy distribution within the cosmic skeleton of theRead More →

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GHOST Commissioning Science Results III: Characterizing an iron-poor damped Lyman $alpha$ system Trystyn A. M. Berg, Christian R. Hayes, Stefano Cristiani, Alan McConnachie, Federico Sestito, Chris Simpson, Fletcher Waller, Timothy Chin, Adam Densmore, Ruben J. Diaz, Michael L. Edgar, Javier Fuentes Lettura, Manuel G’omez-Jim’enez, Venu M. Kalari, Jon Lawrence, Steven Margheim, John Pazder, Roque Ruiz-Carmona, Ricardo Salinas, Karleyne M. G. Silva, Katherine Silversides, Kim A. Venn arXiv:2404.10058v1 Announce Type: new Abstract: The Gemini High-resolution Optical SpecTrograph (GHOST) is a new echelle spectrograph available on the Gemini-South telescope as of Semester 2024A. We present the first high resolution spectrum of the quasar J1449-1227 (redshift z_em=3.27) usingRead More →

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Beyond the Rings: Polar Ring Galaxy NGC 4262 and its Globular Cluster System Akhil Krishna R, Sreeja S Kartha, Blesson Mathew arXiv:2404.10059v1 Announce Type: new Abstract: In the context of the hierarchical model of galaxy evolution, polar ring galaxies (PRGs) are considered the intermediate phase between ongoing mergers and quiescent galaxies. This study explores the globular cluster system (GCS) and its properties in the nearest PRG, NGC4262, serving as a pilot investigation to study GCS in nearby PRGs. We utilize wide and deep field observations of the CFHT as part of the NGVS to investigate the GCS of NGC4262. We presented the first optical imageRead More →

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The outflowing ionised gas of I Zw 1 observed by HST COS A. Jur’av{n}ov’a, E. Costantini, G. A. Kriss, M. Mehdipour, W. N. Brandt, L. Di Gesu, A. C. Fabian, L. Gallo, M. Giustini, D. Rogantini, D. R. Wilkins arXiv:2404.10060v1 Announce Type: new Abstract: We present an analysis of the HST COS spectrum of IZw1 aiming to probe the absorbing medium associated with the active galactic nucleus (AGN). We fitted the emission spectrum and performed spectral analysis of the identified absorption features to derive the corresponding ionic column densities and covering fractions of the associated outflows. We employed photoionisation modelling to constrain the total columnRead More →

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The Rise of the $R$-Process in the Gaia-Sausage/Enceladus Dwarf Galaxy Xiaowei Ou, Alexander P. Ji, Anna Frebel, Rohan P. Naidu, Guilherme Limberg arXiv:2404.10067v1 Announce Type: new Abstract: Neutron star mergers (NSMs) produce copious amounts of heavy r-process elements after a time delayed inspiral process. Once NSMs are present in a galaxy, r-process elements, such as Eu, are expected to significantly increase with time. Yet, there has been limited observational data in support of Eu increasing within Local Group galaxies. We have obtained high-resolution Magellan/MIKE observations of 43 metal-poor stars in the Gaia-Sausage/Enceladus tidally disrupted galaxy with $-2.5 arXiv:2404.10067v1 Announce Type: new Abstract: Neutron star mergersRead More →

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Inclination instability of circumbinary planets Stephen H. Lubow, Anna C. Childs, Rebecca G. Martin arXiv:2404.10080v1 Announce Type: new Abstract: We analyze a tilt instability of the orbit of an outer planet in a two planet circumbinary system that we recently reported. The binary is on an eccentric orbit and the inner circumbinary planet is on a circular polar orbit that causes the the binary to undergo apsidal precession. The outer circumbinary planet is initially on a circular or eccentric orbit that is coplanar with respect to the binary. We apply a Hamiltonian in quadrupole order of the binary potential to show that the tilt instabilityRead More →

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Purple is the new green: biopigments and spectra of Earth-like purple worlds Ligia Fonseca Coelho, Lisa Kaltenegger, Stephen Zinder, William Philpot, Taylor L. Price, Trinity L. Hamilton arXiv:2404.10105v1 Announce Type: new Abstract: With more than 5500 detected exoplanets, the search for life is entering a new era. Using life on Earth as our guide, we look beyond green landscapes to expand our ability to detect signs of surface life on other worlds. While oxygenic photosynthesis gives rise to modern green landscapes, bacteriochlorophyll-based anoxygenic phototrophs can also colour their habitats and could dominate a much wider range of environments on Earth-like exoplanets. Here, we characterize theRead More →