Results 61 to 70 of about 50,261 (220)

Anhydrous minerals in asteroid Bennu: Evidence for well‐preserved primordial components

Meteoritics &Planetary Science, EarlyView.
Abstract Aqueously altered carbonaceous astromaterials are dominated by secondary minerals, but a minor fraction of primary, anhydrous silicates and oxides escape alteration, offering insight into the original composition of asteroid parent bodies. We report the mineralogy, petrology, mineral chemistry, and oxygen isotopes of anhydrous minerals—50 ...
S. S. Russell, I. A. Franchi, T. Salge, X. Zhao, R. H. Jones, A. J. King, N. V. Almeida, P. F. Schofield, H. C. Bates, E. A. Cortes‐Calderon, N. Kawasaki, Y. Yurimoto, Y. Marrocchi, G. Libourel, K. Thomas‐Keprta, L. P. Keller, K. Righter, T. J. McCoy, T. J. Zega, J. J. Barnes, A. N. Nguyen, S. Tachibana, H. C. Connolly Jr, D. S. Lauretta   +23 more
wiley   +1 more source

Spaceborne and spaceborn: Physiological aspects of pregnancy and birth during interplanetary flight

Experimental Physiology, EarlyView.
Abstract Crewed interplanetary return missions that are on the planning horizon will take years, more than enough time for initiation and completion of a pregnancy. Pregnancy is viewed as a sequence of processes – fertilization, blastocyst formation, implantation, gastrulation, placentation, organogenesis, gross morphogenesis, birth and neonatal ...
Arun V. Holden
wiley   +1 more source

Investigating Model Dependencies for Obscured Active Galactic Nuclei: A Case Study of NGC 3982

The Astrophysical Journal
X-ray spectroscopy of heavily obscured active galactic nuclei (AGN) offers a unique opportunity to study the circumnuclear environment of accreting supermassive black holes.
Kristína Kallová, Peter G. Boorman, Claudio Ricci   +2 more
doaj   +1 more source

Early evolutionary history of the seed

Biological Reviews, Volume 101, Issue 3, Page 1511-1553, June 2026.
ABSTRACT The seed is an essential stage in the life history of gymnospermous and angiospermous plants, facilitating both their survival and dispersal. We reappraise knowledge of the evolutionary history of the gymnospermous seed, from its origin in the late Devonian through to the well‐known end‐Permian extinctions – an interval encompassing the ...
Richard M. Bateman, Alan R. T. Spencer, Jason Hilton   +2 more
wiley   +1 more source

Chandra Follow-up Observations of Swift-BAT-selected AGNs III

The Astrophysical Journal
The cosmic X-ray background (CXB) is dominated by the obscured and unobscured coronal light of active galactic nuclei (AGN). At energies below 10 keV, the CXB can be well explained by models taking into account the known AGN and the observed distribution
Isaiah S. Cox, Núria Torres-Albà, Stefano Marchesi, Peter Boorman, Xiurui Zhao, Ross Silver, Marco Ajello, Indrani Pal   +7 more
doaj   +1 more source

Chandra Survey of Nearby Galaxies: A Significant Population of Candidate Central Black Holes in Late-type Galaxies

, 2017
Based on the Chandra data archive as of March 2016, we have identified 314 candidate active galactic nuclei in 719 galaxies located closer than 50 Mpc, among them late-type (Hubble types Sc and later) galaxies that previously had been classified from ...
Feng, Hua, Ho, Luis C., She, Rui
core   +2 more sources

Hard X-ray variability of active galactic nuclei [PDF]

Astronomy & Astrophysics, 2007
Aims. Active Galactic Nuclei are known to be variable throughout the electromagnetic spectrum. An energy domain poorly studied in this respect is the hard X-ray range above 20 keV. Methods. The first 9 months of the Swift/BAT all-sky survey are used to study the 14-195 keV variability of the 44 brightest AGN. The sources have been selected due to their
V. Beckmann, S. D. Barthelmy, T. J.-L. Courvoisier, N. Gehrels, S. Soldi, J. Tueller, G. Wendt   +6 more
openaire   +1 more source

Regional and Seasonal Effects of Geomagnetic Storms on Terrestrial Weather

Geophysical Research Letters, Volume 53, Issue 10, 28 May 2026.
Abstract It has long been a mystery why small Total Solar Irradiation changes have significant effects on Earth's climate. Solar cycle correlation studies abound but cannot conclusively point to a viable physical mechanism. Here, I show that geomagnetic storms have a profound terrestrial weather impact.
J. Raeder
wiley   +1 more source

Testing Physical and Phenomenological Models to Explain the Origin of the Soft Excess in Type-1 AGN

The Astrophysical Journal
Active galactic nuclei (AGN) exhibit an excess of X-ray emission below ∼1 keV compared to the 2–10 keV continuum extrapolation. This feature is commonly named soft excess, and its origin is currently debated for type-1 AGN.
César Ivan Victoria-Ceballos, Omaira González-Martín, Josefa Masegosa, Anna Lia Longinotti, Donaji Esparza-Arredondo, Sinhué A. R. Haro-Corzo   +5 more
doaj   +1 more source

X-ray variability of 104 active galactic nuclei [PDF]

Proceedings of the International Astronomical Union, 2012
AbstractWe have performed a uniform analysis of the power spectrum densities (PSDs) of 104 nearby (z<0.4) active galactic nuclei (AGN) using 209 XMM-Newton/pn observations, including several AGN classes. These PSDs span ≃ 3 decades in temporal frequencies, ranging from minutes to days.
O. González-Martín, S. Vaughan
openaire   +1 more source