Results 1 to 10 of about 603,770 (327)

Structural parameters of star clusters: relations among light, mass and star-count radial profiles and the dependence on photometric depth

, 2007
Structural parameters of model star clusters are measured in radial profiles built from number-density, mass-density and surface-brightness distributions, assuming as well different photometric conditions.
Andreuzzi, Bica, Bonatto, Bonatto, Bonatto, C. Bonatto, Cohen, Djorgovski, E. Bica, Elson, Friel, Girardi, Gnedin, Gnedin, Gratton, Harris, Khalisi, King, King, Lamers, Mackey, Mackey, Mackey, Mackey, Noyola, Salpeter, Trager, Wilson   +27 more
core   +1 more source

Luminance gradient configuration determines perceived lightness in a simple geometric illusion

Frontiers in Human Neuroscience, 2014
Accurate perception of surface reflectance poses a significant computational problem for the visual system. The amount of light reflected by a surface is affected by a combination of factors including the surface’s reflectance properties and illumination
Maria ePereverzeva, Scott O. Murray
doaj   +1 more source

The contribution of the Unresolved Extragalactic Radio Sources to the Brightness Temperature of the sky

, 2008
The contribution of the Unresolved Extragalactic Radio Sources to the diffuse brightness of the sky was evaluated using the source number - flux measurements available in literature.
A. Tartari, Baldwin J. E., Bennett C. L., Birkinshaw M., Burigana C., Colla G., Davis M. M., Fomalont E. B., G. Boella, G. Sironi, Gower I. F. R., Grueff G., Gruppioni C., Hales S. E. G., Katgert J. K., Katgert P., Katgert P., Katgert P., Katgert P., Katgert-Merkelijn J. K., Longair M. S., M. Gervasi, M. Zannoni, Machalski J., McGilchrist M. M., Mills B. Y., Pauliny-Toth I. I. K., Peacock J. A., Peacock J. A., Pearson T. J., Seielstad G. A., Shaver P. A., Vallee J. P., Wall J. V., Wall J. V., Wall J. V., Wilson A. S.   +36 more
core   +1 more source

Physical Characteristics of Small Space Objects at High Orbits Based on Optical Methods [PDF]

Journal of Astronomy and Space Sciences, 2017
Optical observation is one of the most common techniques used for characterizing the physical properties of unknown objects and debris in space. This research presents measurements and properties of the new object 96019 from ground-based optical ...
Afaf M. Abd El-Hameed, Gamal F. Attia, Yehia Abdel-Aziz   +2 more
doaj   +1 more source

From Solar to Stellar Brightness Variations: The Effect of Metallicity

, 2018
Context. Comparison studies of Sun-like stars with the Sun suggest an anomalously low photometric variability of the Sun compared to Sun-like stars with similar magnetic activity.
Krivova, N. A., Schmutz, W., Shapiro, A. I., Solanki, S. K., Witzke, V.   +4 more
core   +1 more source

Environmental Gradients in Lizard Colouration

Ecology and Evolution
Environmental pressures shape animal colouration, facilitating adaptation to local conditions. However, the extent to which climatic gradients drive colour variation in a species across its distributional range remains unclear.
Lekshmi B. Sreelatha, Pedro Tarroso, Ossi Nokelainen, Zbyszek Boratyński, Miguel Angel Carretero   +4 more
doaj   +1 more source

The night sky brightness at Potsdam-Babelsberg

, 2013
We analyze the results of a 2 years (2011--2012) time series of night sky photometry performed at the Leibniz Institute for Astrophysics in Potsdam (AIP).
Posch, Thomas, Puschnig, Johannes, Schwarz, Robert, Schwope, Axel   +3 more
core   +1 more source

The stellar disk thickness of LSB galaxies

, 2004
We present surface photometry results for a sample of eleven edge-on galaxies observed with the 6m telescope at the Special Astrophysical Observatory (Russia).
Barteldrees A., Beijersbergen M., D. Bizyaev, de Blok W. J. G., de Grijs R., de Jong R., Holley-Bockelmann J. K., Karachentsev I., Karachentsev I., Pfenniger D., S. Kajsin, van der Kruit P., Xilouris E. M., Xilouris E. M., Zasov A., Zwaan M.   +15 more
core   +1 more source