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Author : Jeffrey Donald Cooke
Release : 2005
Genre :
Kind : eBook
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Book Synopsis The Mass of Damped Lyman Alpha Systems at High Redshift by : Jeffrey Donald Cooke
Download or read book The Mass of Damped Lyman Alpha Systems at High Redshift written by Jeffrey Donald Cooke. This book was released on 2005. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Karsten Jedamzik
Release : 1998
Genre :
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Book Synopsis Damped Lyman Alpha Systems at High Redshift and Models of Protogalactic Disks by : Karsten Jedamzik
Download or read book Damped Lyman Alpha Systems at High Redshift and Models of Protogalactic Disks written by Karsten Jedamzik. This book was released on 1998. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Ralf Bender
Release : 2003-01-23
Genre : Science
Kind : eBook
Book Rating : 055/5 ( reviews)
Book Synopsis The Mass of Galaxies at Low and High Redshift by : Ralf Bender
Download or read book The Mass of Galaxies at Low and High Redshift written by Ralf Bender. This book was released on 2003-01-23. Available in PDF, EPUB and Kindle. Book excerpt: Measuring the masses of galaxies as a function of redshift is perhaps one of the most challenging open issues in current astronomical research. The evolution of the baryonic and dark matter components of galaxies is not only a critical test of the hierarchical formation paradigm, but ultimately also provides new clues on the complex interplay between star formation, the cooling and heating of gas and galaxy merging processes. This book reviews current techniques to measure the baryonic (stellar) and dark masses of nearby galaxies, and focusses on ongoing attempts to measure theses same quantities in galaxies at higher and higher redshifts. It also gives room to future perspectives, with special emphasis on new survey projects and satellite missions.
Author : Regina A. Jorgenson
Release : 2008
Genre :
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Book Synopsis Physical Conditions in Damped Lyman Alpha Systems by : Regina A. Jorgenson
Download or read book Physical Conditions in Damped Lyman Alpha Systems written by Regina A. Jorgenson. This book was released on 2008. Available in PDF, EPUB and Kindle. Book excerpt: The primary goal of this thesis is to determine physical conditions in high redshift galaxies known as Damped Lymna alpha Systems. To this end, we present several key results. First, we discuss a radio-selected quasar survey that demonstrates that dust bias is likely not an issue affecting surveys for DLAs. In other words, we are seeing the true and complete population of DLAs and not missing some very high column density, dusty DLAs . Second, we use neutral carbon (CI) fine structure states to show the presence of gas with densities and pressures 1-2 orders of magnitude larger than those expected in the global DLA, i.e. the presence of knots of dense cold gas existing in the larger diffuse DLA. To solve the imbalance of pressure between these two phases, we speculate that these regions are created by shocks that provide relatively high densities that in turn allow for the existence of CI. Alternatively, these could be photodissociation regions on the edges of even more dense molecular clouds that could even be hosting star formation. This model would explain the presence of a radiation field generally above the background. We also present unambiguous evidence of the presence of cold gas in DLAs -- the discovery of narrow sub-resolution, sub-1 km s−1 CI components with thermal temperatures
Author : M.N. Bremer
Release : 2012-12-06
Genre : Science
Kind : eBook
Book Rating : 260/5 ( reviews)
Book Synopsis Cold Gas at High Redshift by : M.N. Bremer
Download or read book Cold Gas at High Redshift written by M.N. Bremer. This book was released on 2012-12-06. Available in PDF, EPUB and Kindle. Book excerpt: Recent years have seen increasing evidence that the main epoch of galaxy formation in the universe may be directly accessible to observation. An gular fluctuations in the background relict radiation have been detected by various ground-based instruments as well as by the COBE satellite, and suggest that the epoch of galaxy formation was not so very early. Combined optical and radio studies have found galaxies at redshifts above 2. 0, systems that at least superficially show the characteristics expected of large galaxies seen only shortly after their formation. And absorption lines in the spectra of quasars seem to be telling us that most cold gas at early to intermediate cosmological epochs was in clouds having roughly galaxy sized masses. What kinds of new observations will best help us study this high redshift universe in future? What new instruments will be needed? These are questions that loom large in the minds of the Dutch astronom ical community as we celebrate 25 years of operation of the Westerbork Synthesis Radio Telescope. Celebration of this Silver Jubilee has included a birthday party (on 23 June, 1995), a commemorative volume looking at both the history and the future of the facility ("The Westerbork Observa tory, Continuing Adventure in Radio Astronomy," Kluwer 1996), and an international workshop, held in the village of Hoogeveen on 28-30 August, 1995.
