Results 31 to 40 of about 28,808 (222)

Maser emission in planetary nebulae [PDF]

Proceedings of the International Astronomical Union, 2007
AbstractStars at the top of the asymptotic giant branch (AGB) can exhibit maser emission from molecules like SiO, H2O and OH. These masers appear in general stratified in the envelope, with the SiO masers close to the central star and the OH masers farther out in the envelope.
openaire   +2 more sources

A Comprehensive Catalog of Emission-line Nebulae, Star Clusters, and Supergiants in M31 from the LAMOST Spectroscopic Survey

The Astronomical Journal
Spectroscopic observations of various tracers in nearby galaxies, such as Andromeda (M31), play a crucial role in identifying and classifying individual stellar populations and nebular objects, thereby enhancing our understanding of galactic composition,
Pinjian Chen, Bingqiu Chen, Xuan Fang, Haibo Yuan, Baisong Zhang, Xiangwei Zhang, Jiarui Sun, Xiaowei Liu   +7 more
doaj   +1 more source

The imprint of AGN-driven outflows on the Circumgalactic Medium: The case of Lyα nebulae around high-z quasars

Astronomy & Astrophysics
Some cosmological hydrodynamical simulations predict that outflows driven by active galactic nuclei (AGN) play a key role in powering the Lyα nebulae observed around high-redshift quasars.
Rueda-Vargas Silvia C., Mainieri Vincenzo, Tozzi Giulia, Kakkad Darshan, Arrigoni-Battaia Fabrizio, Costa Tiago, Farina Emanuele Paolo, Harrison Chris M.   +7 more
doaj   +1 more source

Luminosity indicators in dusty photoionized environments [PDF]

, 1998
The luminosity of the central source in ionizing radiation is an essential parameter in a photoionized environment, and one of the most fundamental physical quantities one can measure.
Dejan  Vinković, Ekaterina  Verner, Emmanuel  Momjian, Engelbracht C. W., Gary  Ferland, Hummer D., Joseph  LaMothe, Mark  Bottorff, Oliveira S. A., Storey P. J., van de Steene G. C.   +10 more
core   +2 more sources

Accounting for the Opportunity Cost of Children's Time in Economic Evaluation: Challenges and Frequently Asked Questions

Health Economics, EarlyView.
ABSTRACT Economic evaluations carried out from a societal perspective ought to account for the opportunity cost of a range of resources, including those committed by care recipients. People's time is such a resource: it is limited, valuable and it has an opportunity cost that should be reflected in cost calculations.
Lazaros Andronis, Cameron Morgan, Cam Donaldson, Emily Lancsar, Stavros Petrou   +4 more
wiley   +1 more source

WISE morphological study of Wolf-Rayet nebulae

, 2015
We present a morphological study of nebulae around Wolf-Rayet (WR) stars using archival narrow-band optical and Wide-field Infrared Survey Explorer (WISE) infrared images.
Guerrero, M. A., Guzmán, V., Ramos-Larios, G., Toalá, J. A.   +3 more
core   +1 more source

Nebular Abundance Errors [PDF]

, 1997
The errors inherent to the use of the standard "ionization correction factor" ("i_CF") method of calculating nebular conditions and relative abundances of H, He, N, O, Ne, S, and Ar in emission line nebulae have been investigated under conditions typical
Alexander, J., Balick, B.
core   +3 more sources

HOUSING QUESTION OLD AND NEW: Mapping Crowding, Tenure, Rents and Segregation in the Neighborhoods of Major European Cities around 1900 and Today

International Journal of Urban and Regional Research, EarlyView.
Abstract In a context of unprecedented urbanization, nineteenth‐century European cities faced the ‘housing question’, i.e. precarious housing standards and affordability problems. While existing research has well described these historical housing problems in single‐city studies or in national urbanization histories, to our knowledge, there are hardly ...
Sebastian Kohl, Florian Müller, Ria Wilken   +2 more
wiley   +1 more source

An Ensemble Study of Turbulence in Extended QSO Nebulae at z ≈ 0.5–1

The Astrophysical Journal
Turbulent motions in the circumgalactic medium play a critical role in regulating the evolution of galaxies, yet their detailed characterization remains elusive. Using two-dimensional velocity maps constructed from spatially extended [O ii ] and [O iii ]
Mandy C. Chen, Hsiao-Wen Chen, Michael Rauch, Zhijie Qu, Sean D. Johnson, Joop Schaye, Gwen C. Rudie, Jennifer I-Hsiu Li, Zhuoqi (Will) Liu, Fakhri S. Zahedy, Sebastiano Cantalupo, Erin Boettcher   +11 more
doaj   +1 more source

Evolved Pulsar Wind Nebulae

Universe, 2023
Based on the expected population of core collapse supernova remnants and the huge number of detected pulsars in the Galaxy, still representing only a fraction of the real population, pulsar wind nebulae are likely to constitute one of the largest classes
Barbara Olmi
doaj   +1 more source