Results 1 to 10 of about 4,164,367 (209)

The Host Galaxy Fluxes of Active Galaxy Nuclei Are Generally Overestimated by the Flux Variation Gradient Method [PDF]

Universe
In terms of the variable nature of normal active galaxy nuclei (AGN) and luminous quasars, a so-called flux variation gradient (FVG) method has been widely utilized to estimate the underlying non-variable host galaxy fluxes.
Minxuan Cai, Zhen Wan, Zhenyi Cai, Lulu Fan, Junxian Wang   +4 more
doaj   +2 more sources

Atmospheric Optical Turbulence Characteristics over the Ocean Relevant to Astronomy and Atmospheric Physics

Applied Sciences, 2021
Due to the space and time constraints of turbulence measurement equipment and the experiment scene, it is difficult to obtain the atmosphere refractive index structure constant over the ocean.
Manman Xu, Shiyong Shao, Ningquan Weng, Liangping Zhou, Qing Liu, Yuefeng Zhao   +5 more
doaj   +2 more sources

The Orbit and Dynamical Mass of Polaris: Observations with the CHARA Array [PDF]

The Astrophysical Journal
The 30 yr orbit of the Cepheid Polaris has been followed with observations by the Center for High Angular Resolution Astronomy (CHARA) Array from 2016 through 2021.
Nancy Remage Evans, Gail H. Schaefer, Alexandre Gallenne, Guillermo Torres, Elliott P. Horch, Richard I. Anderson, John D. Monnier, Rachael M. Roettenbacher, Fabien Baron, Narsireddy Anugu, James W. Davidson Jr., Pierre Kervella, Garance Bras, Charles Proffitt, Antoine Mérand, Margarita Karovska, Jeremy Jones, Cyprien Lanthermann, Stefan Kraus, Isabelle Codron, Howard E. Bond, Giordano Viviani   +21 more
doaj   +2 more sources

A Review of the Characteristics of Light Pollution: Assessment Technique, Policy, and Legislation

Energies
Light pollution from the use of artificial lighting poses significant impacts on human health, traffic safety, ecological environment, astronomy, and energy use.
Ying Hao, Peiyao Wang, Zhongyao Zhang, Zhiming Xu, Dagong Jia   +4 more
doaj   +2 more sources

Meteor Radar for Investigation of the MLT Region: A Review

Atmosphere
This is an introductory review of modern meteor radar and its application to the measurement of the dynamical parameters of the Mesosphere Lower Thermosphere (MLT) Region within the altitude range of around 70 to 110 km, which is where most meteors are ...
Iain M. Reid
doaj   +2 more sources

Multilingual performance of a multimodal artificial intelligence system on multisubject physics concept inventories

Physical Review Physics Education Research
We investigate the multilingual and multimodal performance of a large language model-based artificial intelligence (AI) system, GPT-4o, using a diverse set of physics concept inventories spanning multiple languages and subject categories. The inventories,
Gerd Kortemeyer, Marina Babayeva, Giulia Polverini, Ralf Widenhorn, Bor Gregorcic   +4 more
doaj   +2 more sources

Photon ring test of the Kerr hypothesis: Variation in the ring shape [PDF]

Astronomy & Astrophysics, 2022
The Event Horizon Telescope (EHT) collaboration recently released horizon-scale images of the supermassive black hole M87*. These images are consistently described by an optically thin, lensed accretion flow in the Kerr spacetime. General relativity (GR)
Hadrien Paugnat, A. Lupsasca, Frédéric E. Vincent, M. Wielgus   +3 more
semanticscholar   +1 more source

Weighted Anisotropic–Isotropic Total Variation for Poisson Denoising [PDF]

International Conference on Information Photonics, 2023
Poisson noise commonly occurs in images captured by photon-limited imaging systems such as in astronomy and medicine. As the distribution of Poisson noise depends on the pixel intensity value, noise levels vary from pixels to pixels.
Kevin Bui, Yifei Lou, Fredrick Park, J. Xin   +3 more
semanticscholar   +1 more source

Follow-up timing of 24 pulsars discovered in commensal radio astronomy FAST survey

Monthly notices of the Royal Astronomical Society, 2023
The follow-up timing observations were carried out for 24 pulsars discovered with the Five-hundred-meter Aperture Spherical radio Telescope (FAST) in Commensal Radio Astronomy FAST Survey (CRAFTS).
Q. Wu, J. Yuan, N. Wang, D. Li, P. Wang, M. Xue, W. Zhu, C. Miao, W. M. Yan, J. Wang, J. M. Yao, S. Wang, S. N. Sun, F. Kou, Z. Tu, J. Xie, Z. Pan, D. Zhao, Y. T. Chen, S. Dang, Y. Feng, Z. Liu, X. Miao, L. Meng, M. Yuan, C. Niu, J. Niu, L. Qian, S. Wang, X. Y. Xie, Y. Xiao, Y. Yue, S. You, X. Yu, R. Zhao, L. Zhang, R. Yuen, Z. Wen, H. M. Tedila   +38 more
semanticscholar   +1 more source

Re-detection and a possible time variation of soft X-ray polarization from the Crab [PDF]

Nature Astronomy, 2020
The Crab nebula is so far the only celestial object with a statistically significant detection in soft X-ray polarimetry1–4, a window that has not been explored in astronomy since the 1970s.
H. Feng, Hong Li, X. Long, R. Bellazzini, E. Costa, Qiong Wu, Jiahui Huang, Weichun Jiang, M. Minuti, Weihua Wang, Renxin Xu, Dongxin Yang, L. Baldini, S. Citraro, H. Nasimi, P. Soffitta, F. Muleri, A. Jung, Jiandong Yu, Ge Jin, M. Zeng, Peng An, A. Brez, L. Latronico, C. Sgro’, G. Spandre, M. Pinchera   +26 more
semanticscholar   +1 more source