Structure of an Absorbing Medium in the Nucleus of the Galaxy Mrk 417 Based on NuSTAR and Swift/Bat Data

Astrophysics ◽  
2020 ◽  
Vol 63 (3) ◽  
pp. 307-321
Author(s):  
O.V. Kompaniiets ◽  
A. A. Vasylenko
Keyword(s):  
1966 ◽  
Vol 24 ◽  
pp. 101-110
Author(s):  
W. Iwanowska

In connection with the spectrophotometric study of population-type characteristics of various kinds of stars, a statistical analysis of kinematical and distribution parameters of the same stars is performed at the Toruń Observatory. This has a twofold purpose: first, to provide a practical guide in selecting stars for observing programmes, second, to contribute to the understanding of relations existing between the physical and chemical properties of stars and their kinematics and distribution in the Galaxy.


1967 ◽  
Vol 31 ◽  
pp. 313-317 ◽  
Author(s):  
C. C. Lin ◽  
F. H. Shu

Density waves in the nature of those proposed by B. Lindblad are described by detailed mathematical analysis of collective modes in a disk-like stellar system. The treatment is centered around a hypothesis of quasi-stationary spiral structure. We examine (a) the mechanism for the maintenance of this spiral pattern, and (b) its consequences on the observable features of the galaxy.


1967 ◽  
Vol 31 ◽  
pp. 239-251 ◽  
Author(s):  
F. J. Kerr

A review is given of information on the galactic-centre region obtained from recent observations of the 21-cm line from neutral hydrogen, the 18-cm group of OH lines, a hydrogen recombination line at 6 cm wavelength, and the continuum emission from ionized hydrogen.Both inward and outward motions are important in this region, in addition to rotation. Several types of observation indicate the presence of material in features inclined to the galactic plane. The relationship between the H and OH concentrations is not yet clear, but a rough picture of the central region can be proposed.


1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.


1997 ◽  
Vol 161 ◽  
pp. 419-429 ◽  
Author(s):  
Antonio Lazcano

AbstractDifferent current ideas on the origin of life are critically examined. Comparison of the now fashionable FeS/H2S pyrite-based autotrophic theory of the origin of life with the heterotrophic viewpoint suggest that the later is still the most fertile explanation for the emergence of life. However, the theory of chemical evolution and heterotrophic origins of life requires major updating, which should include the abandonment of the idea that the appearance of life was a slow process involving billions of years. Stability of organic compounds and the genetics of bacteria suggest that the origin and early diversification of life took place in a time period of the order of 10 million years. Current evidence suggest that the abiotic synthesis of organic compounds may be a widespread phenomenon in the Galaxy and may have a deterministic nature. However, the history of the biosphere does not exhibits any obvious trend towards greater complexity or «higher» forms of life. Therefore, the role of contingency in biological evolution should not be understimated in the discussions of the possibilities of life in the Universe.


2006 ◽  
Vol 20 ◽  
pp. 277-278
Author(s):  
B. Famaey ◽  
J. Binney
Keyword(s):  

2020 ◽  
Vol 75 (1) ◽  
pp. 50-81
Author(s):  
Brook Thomas

Brook Thomas, “The Galaxy, National Literature, and Reconstruction” (pp. 50–81) The North’s victory in the Civil War preserved the Union and led to the abolition of slavery. Reconstruction was a contentious debate about what sort of nation that union of states should become. Published during Reconstruction before being taken over by the Atlantic Monthly, the Galaxy tried, in Rebecca Harding Davis’s words, to be “a national magazine in which the current of thought of every section could find expression.” The Galaxy published literature and criticism as well as political, sociological, and economic essays. Its editors were moderates who aesthetically promoted a national literature and politically promoted reconciliation between Northern and Southern whites along with fair treatment for freedmen. What fair treatment entailed was debated in its pages. Essayists included Horace Greeley, the abolitionist journalist; Edward A. Pollard, author of The Lost Cause (1866); and David Croly, who pejoratively coined the phrase “miscegenation.” Literary contributors included Davis, Walt Whitman, Henry James, Mark Twain, Constance Fenimore Woolson, John William De Forest, Julian Hawthorne, Emma Lazarus, Paul Hayne, Sidney Lanier, and Joaquin Miller. Juxtaposing some of the Galaxy’s literary works with its debates over how the Union should be reimagined points to the neglected role that Reconstruction politics played in the institutionalization of American literary studies. Whitman is especially important. Reading the great poet of American democracy in the context of the Galaxy reveals how his postbellum celebration of a united nation—North, South, East, and West—aligns him with moderate views on Reconstruction that today seem racially reactionary.


Author(s):  
Karel Schrijver

How many planetary systems formed before our’s did, and how many will form after? How old is the average exoplanet in the Galaxy? When did the earliest planets start forming? How different are the ages of terrestrial and giant planets? And, ultimately, what will the fate be of our Solar System, of the Milky Way Galaxy, and of the Universe around us? We cannot know the fate of individual exoplanets with great certainty, but based on population statistics this chapter sketches the past, present, and future of exoworlds and of our Earth in general terms.


Sign in / Sign up

Export Citation Format

Share Document