Results 41 to 50 of about 53,848 (207)

Discovery and Initial Investigation of a New Low Surface Brightness Planetary Nebula Candidate at High Galactic Latitude

Astronomische Nachrichten, Volume 347, Issue 3, March 2026.
ABSTRACT Planetary nebulae represent a late evolutionary phase of low‐ to intermediate‐mass stars. In this article, we present the serendipitous discovery of a previously unknown, faint potential Galactic planetary nebula (PN) in the constellation Camelopardalis, identified during a survey‐inspection, aiming at the detection of dwarf companions of the ...
W. E. Celnik, P. Köchling, S. Kotov, J. Kozok, Y. Galata, L. Magrini, A. Moiseev, M. Nischang, C. Reese, P. Remmel, P. Riepe, T. Zilch, K. Werner   +12 more
wiley   +1 more source

Can Fractal Dimension Distinguish between Grand-design and Flocculent Spiral Arms?

The Astrophysical Journal
About two-thirds of disk galaxies host spiral arms, ranging from well-delineated grand-design spirals to fragmented flocculent spiral galaxies. We introduce fractal dimension D _B as a nonparametric measure to distinguish between grand-designs and ...
Biju Saha, Subhadip Dutta, Arunima Banerjee   +2 more
doaj   +1 more source

Reduced Geomagnetic Shielding During the Laschamps Excursion and Its Impact on Cosmic‐Ray‐Induced Atmospheric Radiation

Journal of Geophysical Research: Space Physics, Volume 131, Issue 2, February 2026.
Abstract The Laschamps geomagnetic excursion (≈41,000 years BP) was a period of significant weakening and incomplete reversal of the Earth's magnetic field. The weakening substantially reduced geomagnetic shielding against cosmic rays (CRs), which contribute to phenomena at Earth, such as cosmogenic isotope production, and atmospheric ionisation and ...
N. Larsen, I. Usoskin, A. Mishev, S. Koldobskiy, P. Väisänen   +4 more
wiley   +1 more source

On the Kinematic Nature of Apparent Disks at High Redshifts: Local Counterparts are Not Dominated by Ordered Rotation but by Tangentially Anisotropic Random Motion

The Astrophysical Journal Letters
It is not straightforward to physically interpret the apparent morphology of galaxies. Recent observations by the James Webb Space Telescope (JWST) revealed a dominant galaxy population at high redshifts ( z > 2) that were visually classified as disks ...
Bitao Wang, Yingjie Peng, Michele Cappellari, Hua Gao, Houjun Mo   +4 more
doaj   +1 more source

The Chinese Radio Telescope Array for Interplanetary Scintillation Monitoring

Space Weather, Volume 24, Issue 1, January 2026.
Abstract Solar flares, coronal mass ejections (CMEs) and enegertic particles, etc., are the driving sources that may cause catastrophic space weathers. It is desirable to obtain information of solar eruptions like flares and CMEs, etc., propagating from the Sun to the near‐Earth space.
Yihua Yan, Wei Wang, Jin Fan, Ming Xiong, Zhijun Chen, Linjie Chen, Cang Su, Sha Li, Jun Cheng, Jing Du, Xueshang Feng   +10 more
wiley   +1 more source

Observational Problems in Extragalactic Astronomy [PDF]

Highlights of Astronomy, 1992
AbstractA large number of observations have accumulated which represent baffling mysteries from the standpoint of current astronomy. A sample of the most crucial of these cases is reviewed and updated. Evidence has slowly built up to the point where often each individual object is a formidable challenge to conventional theory. But, most importantly, it
openaire   +1 more source

The Stochastic‐Dissipative Störmer Problem‐Trajectories and Radiation Patterns

Annalen der Physik, Volume 537, Issue 12, December 2025.
We consider charged particle motion and radiation in a dipole magnetic field, in the presence of friction and of stochastic forces. The numerical solutions of the Langevin equation reveal how these forces modify the complex dynamics of particles, and they offer some new insights into the nonlinear processes relevant to planetary radiation belts ...
Tiberiu Harko, Gabriela Raluca Mocanu
wiley   +1 more source

Synchrotron and Compton Components and their Variability in BL Lac Objects

, 2000
BL Lacertae objects are extreme extragalactic sources characterized by the emission of strong and rapidly variable nonthermal radiation over the entire electromagnetic spectrum.
Ghisellini, G., Giommi, P., Padovani, P., Tagliaferri, G.   +3 more
core   +2 more sources

A Comparative Study of VTEC Estimates Derived From S/X VLBI and VGOS Observations

Space Weather, Volume 23, Issue 12, December 2025.
Abstract The ionosphere, which strongly varies in time and space, is one of the largest error sources for microwave measurements, if not accounted for accurately. Especially for single‐frequency observations, precise ionospheric models are needed to correct for the ionospheric delays. This study explores the utility of Very Long Baseline Interferometry
Arno Rüegg, Grzegorz Kłopotek, Benedikt Soja   +2 more
wiley   +1 more source

Revisiting Galaxy Cluster Scaling Relations through Dark Matter–Gas Coherence: Scatter Dependence on Dynamical State

The Astrophysical Journal
Galaxy clusters, the most massive, dark-matter-dominated, and most recently assembled structures in the Universe, are key tools for probing cosmology.
Giulia Cerini, Elena Bellomi, Nico Cappelluti, Sabina Khizroev, Erwin T. Lau, Priyamvada Natarajan, John ZuHone   +6 more
doaj   +1 more source