Highlights in modern observational cosmology

2001 ◽  
Author(s):  
Piero Rosati
Keyword(s):  
Observational Cosmology

Astronomy on Ice

1986 ◽  
Vol 6 (4) ◽  
pp. 403-415 ◽  
Author(s):  
Martin A. Pomerantz
Keyword(s):  
Gamma Ray ◽  
Far Infrared ◽  
The United States ◽  
High Energy ◽  
Observational Cosmology ◽  
Significant Information ◽  
Infrared Measurements ◽  
Energy Gamma ◽  
Low Humidity ◽  
Scientific Station

AbstractThe geographic South Pole, where the United States maintains a year-round scientific station, affords a number of unique advantages for certain types of astronomical observations. These include: continuous viewing and constant declination of ail objects in the southern celestial hemisphere, exceedingly low humidity, extended periods of coronal seeing, high altitude, and uniform terrain. The areas of research that have already benefited immensely from thèse extraordinary features are helioseismology and submillimeter astronomy. Unparalleled observations of global solar oscillations have already yielded significant information about the structure and dynamics of the Sun’s interior. Far infrared measurements of various galactic and extra-galactic regions have attained an unprecedented level of sensitivity, limited for the first time only by the noise inherent in the detector. In addition to further helioseismological observations, currently planned future activities include observational cosmology and ultra high energy gamma ray astronomy.

Origin and evolution of the large-scale structure of the universe

1990 ◽  
Vol 68 (9) ◽  
pp. 799-807
Author(s):  
Joseph Silk
Keyword(s):  
Large Scale ◽  
Background Radiation ◽  
Building Blocks ◽  
Large Scale Structure ◽  
Big Bang ◽  
Scale Structure ◽  
Observational Cosmology ◽  
Spontaneous Breaking ◽  
Fluctuation Spectrum ◽  
The Universe

Ever since the epoch of the spontaneous breaking of grand unification symmetry between the nuclear and electromagnetic interactions, the universe has expanded under the imprint of a spectrum of density fluctuations that is generally considered to have originated in this phase transition. I will discuss various possibilities for the form of the primordial fluctuation spectrum, spanning the range of adiabatic fluctuations, isocurvature fluctuations, and cosmic strings. Growth of the seed fluctuations by gravitational instability generates the formation of large-scale structures, from the scale of galaxies to that of clusters and superclusters of galaxies. There are three areas of confrontation with observational cosmology that will be reviewed. The large-scale distribution of the galaxies, including the apparent voids, sheets and filaments, and the coherent peculiar velocity field on scales of several tens of megaparsecs, probe the primordial fluctuation spectrum on scales that are only mildly nonlinear. Even larger scales are probed by study of the anisotropy of the cosmic microwave background radiation, which provides a direct glimpse of the primordial fluctuations that existed about 106 years or so after the initial big bang singularity. Galaxy formation is the process by which the building blocks of the universe have formed, involving a complex interaction between hydrodynamical and dynamical processes in a collapsing gas cloud. Both by detection of forming galaxies in the most remote regions of the universe and by study of the fundamental morphological characteristics of galaxies, which provide a fossilized memory of their past, can one relate the origin of galaxies to the same primordial fluctuation spectrum that gave rise' to the large-scale structure of the universe.

Observational Cosmology Impacts Physics

1995 ◽  
Vol 8 (3) ◽  
pp. 350-365 ◽  
Author(s):  
Halton Arp
Keyword(s):  
Observational Cosmology

scholarly journals Observational Cosmology 1986: A summary of IAU Symposium No 124, Beijing, China

1987 ◽  
Vol 124 ◽  
pp. 823-840
Author(s):  
M S Longair
Keyword(s):  
Observational Cosmology ◽  
The Real ◽  
Personal Bias ◽  
New Material ◽  
Beijing China

“This symposium marks the real beginning of observational cosmology”, Allan Sandage, 29 August 1986.It is a pleasure to be invited to attempt to summarise the very intense work of the last 6 days. Virtually all aspects of contemporary observational cosmology have been described and debated and it is my task to try to put this wealth of new material into context. As in all such surveys, allowance must be made for personal bias - like everyone else, I am sure I am giving an unbiased view but you must judge for yourselves!

The Application of the Study of Galaxies Associated With Quasars to Observational Cosmology

1987 ◽  
Vol 124 ◽  
pp. 685-689
Author(s):  
H.K.C. Yee
Keyword(s):  
Galaxy Clusters ◽  
Count Data ◽  
Luminosity Function ◽  
Current Data ◽  
Observational Cosmology ◽  
Direct Imaging ◽  
Large Uncertainty ◽  
Self Consistent ◽  
Galaxy Count

CCD direct imaging of fields around quasars is used as a method for locating galaxy clusters and groups associated with quasars. Average galaxy counts in the sky obtained from control fields are used to correct for background galaxies in the quasar fields. This correction allows one to derive the luminosity function (LF) of the associated galaxies at the redshifts of the quasars. It is demonstrated that using the derived LF and average galaxy count data, self-consistent models of the evolution of the LF and galaxy counts can be obtained. Current data are best fitted, with a large uncertainty, by a qo between 0.0 and 0.5 and an evolution in M* of −0.9±0.5 mag. It is found that the average environment of radio-loud quasars at z∼0.6 is about three times richer in galaxies than that of quasars at z∼0.4.

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