Results 111 to 120 of about 77,605 (280)

Megamasers in Active Galactic Nuclei [PDF]

open access: yesHighlights of Astronomy, 1998
Extragalactic masers were discovered more than 20 years ago (Whiteoak & Gardner 1973). It soon became apparent that those extragalactic masers we can detect are intrinsically very powerful and are located in galactic nuclei. The term Megamaser was coined to describe the most luminous OH masers, which are a million times more powerful than any OH ...
openaire   +2 more sources

VIS‐to‐MIR reflectance and Raman spectroscopy of the CM2 NWA 12184 carbonaceous chondrite

open access: yesMeteoritics &Planetary Science, Volume 60, Issue 3, Page 570-595, March 2025.
Abstract The spectral analysis of CM meteorites can help to constrain the mineralogical composition of their parent body, the C‐type asteroids. The CM2 NWA 12184 was spectrally examined employing seven complementary techniques at different spatial resolutions, including VIS‐to‐MIR reflectance and Raman spectroscopy.
A. Galiano   +15 more
wiley   +1 more source

X-Ray Polarization Variability of High Spectral Peak BL Lacertaes: Cases of 1ES 1959+650 and PKS 2155–304

open access: yesThe Astrophysical Journal Letters
The high-energy-peaked BL Lacertae objects (HBLs) are the main targets of the Imaging X-ray Polarimetry Explorer (IXPE) for investigating the mechanisms of radiation and particle acceleration in jets. In this Letter, we report the first IXPE observations
Xin-Ke Hu   +7 more
doaj   +1 more source

Technical considerations and review of urinary microRNAs as biomarkers for chronic kidney disease in dogs and cats

open access: yesVeterinary Clinical Pathology, EarlyView.
Abstract MicroRNAs (miRNAs or miRs) are small, non‐coding RNAs that play a crucial role in gene regulation, making them potential biomarkers for various diseases. In the field of veterinary medicine, there is a growing interest in exploring the diagnostic and therapeutic potential of miRNAs in kidney diseases affecting dogs and cats.
Candice P. Chu, Mary B. Nabity
wiley   +1 more source

Reverberation mapping of active galactic nuclei

open access: yesAstronomische Nachrichten, 2004
AbstractEcho mapping makes use of the intrinsic variaibility of the continuum source in active galactic nuclei to map out the distribution and kinematics of line‐emitting gas from its light travel time‐delayed response to continuum changes. Echo mapping experiments have yielded sizes for the broad line‐emitting region in about three dozen AGNs.
Keith Horne, Bradley M. Peterson
openaire   +4 more sources

A Long-term Study of Mrk 50: Appearance and Disappearance of Soft Excess

open access: yesThe Astrophysical Journal
We present an extensive temporal and spectral study of the Seyfert 1 AGN Mrk 50 using 15 yr (2007–2022) of multiwavelength observations from XMM-Newton, Swift, and NuSTAR for the first time.
Narendranath Layek   +3 more
doaj   +1 more source

On the Extended Soft X-Ray and Fe Kα Emission in NGC 1068

open access: yesThe Astrophysical Journal
The soft X-ray excess and Fe K α emission lines are widely observed in Seyfert galaxies, with their origin still in debate. We present a detailed spatially resolved image and spectral analysis of the Seyfert 2 galaxy NGC 1068 using high-resolution ...
Songbo Gao, Hongxing Yin, Shaoming Hu
doaj   +1 more source

The environment of active galactic nuclei – I. A two-component broad emission line model [PDF]

open access: bronze, 1988
S. Collin-Souffrin   +3 more
openalex   +1 more source

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

open access: yesExperimental 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

On the Extremely X-Ray Variable Active Galactic Nuclei in the XMM-LSS Field

open access: yesThe Astrophysical Journal
We present a systematic investigation of extremely X-ray variable active galactic nuclei (AGNs) in the ≈5.3 deg ^2 XMM-SERVS XMM-LSS region. Eight variable AGNs are identified with rest-frame 2 keV flux density variability amplitudes around 6–12.
Zijian Zhang   +5 more
doaj   +1 more source

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