Author: Jeffrey Donald Cooke
Publisher:
ISBN:
Category :
Languages : en
Pages : 630
Book Description
The Mass of Damped Lyman Alpha Systems at High Redshift
Author: Jeffrey Donald Cooke
Publisher:
ISBN:
Category :
Languages : en
Pages : 630
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 630
Book Description
Damped Lyman Alpha Systems at High Redshift and Models of Protogalactic Disks
The Mass of Galaxies at Low and High Redshift
Author: Ralf Bender
Publisher: Springer Science & Business Media
ISBN: 9783540002055
Category : Science
Languages : en
Pages : 394
Book Description
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.
Publisher: Springer Science & Business Media
ISBN: 9783540002055
Category : Science
Languages : en
Pages : 394
Book Description
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.
Physical Conditions in Damped Lyman Alpha Systems
Author: Regina A. Jorgenson
Publisher:
ISBN:
Category :
Languages : en
Pages : 236
Book Description
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
Publisher:
ISBN:
Category :
Languages : en
Pages : 236
Book Description
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
Galaxies at High Redshift
Author: I. Pérez-Fournon
Publisher: Cambridge University Press
ISBN: 9780521825917
Category : Science
Languages : en
Pages : 302
Book Description
This volume presents lectures of the XI Canary Islands Winter School of Astrophysics written by experts in the field.
Publisher: Cambridge University Press
ISBN: 9780521825917
Category : Science
Languages : en
Pages : 302
Book Description
This volume presents lectures of the XI Canary Islands Winter School of Astrophysics written by experts in the field.
Cold Gas at High Redshift
Author: M.N. Bremer
Publisher: Springer Science & Business Media
ISBN: 9400917260
Category : Science
Languages : en
Pages : 448
Book Description
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.
Publisher: Springer Science & Business Media
ISBN: 9400917260
Category : Science
Languages : en
Pages : 448
Book Description
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.
QSO Absorption Lines
Author: Georges Meylan
Publisher: Springer Science & Business Media
ISBN: 3540494588
Category : Science
Languages : en
Pages : 481
Book Description
The controversial question of whether the majority of the narrow absorption lines observed in QSO spectra represent cosmological intervening systems or ejecta from the QSO themselves is settled. QSO absorption line spectroscopy, initially a mere technique, has matured into an essential extragalactic research tool for understanding the content of the Universe at redshifts between 0 and 4, and beyond. The only previous important meeting devoted to "QSO Absorption Lines" was held in May 1987 at the Space Telescope Science Institute in Baltimore, Maryland, U.S.A. Since that time, nearly a decade ago, research has been ex tremely active in this now well-established field of astrophysics. Theoretical stud ies and simulations have taken advantage of the constant progress in computer technology, and during these last few years, the observational results have bene fited largely from the new facillities offered by the Hubble Space Telescope in the UV wavelength range and the Keck Telescope for high-resolution spectroscopy.
Publisher: Springer Science & Business Media
ISBN: 3540494588
Category : Science
Languages : en
Pages : 481
Book Description
The controversial question of whether the majority of the narrow absorption lines observed in QSO spectra represent cosmological intervening systems or ejecta from the QSO themselves is settled. QSO absorption line spectroscopy, initially a mere technique, has matured into an essential extragalactic research tool for understanding the content of the Universe at redshifts between 0 and 4, and beyond. The only previous important meeting devoted to "QSO Absorption Lines" was held in May 1987 at the Space Telescope Science Institute in Baltimore, Maryland, U.S.A. Since that time, nearly a decade ago, research has been ex tremely active in this now well-established field of astrophysics. Theoretical stud ies and simulations have taken advantage of the constant progress in computer technology, and during these last few years, the observational results have bene fited largely from the new facillities offered by the Hubble Space Telescope in the UV wavelength range and the Keck Telescope for high-resolution spectroscopy.
Lyman-alpha as an Astrophysical and Cosmological Tool
Author: Mark Dijkstra
Publisher: Springer Nature
ISBN: 3662596237
Category : Science
Languages : en
Pages : 421
Book Description
The hydrogen Lyman-alpha line is of utmost importance to many fields of astrophysics. This UV line being conveniently redshifted with distance to the visible and even near infrared wavelength ranges, it is observable from the ground, and provides the main observational window on the formation and evolution of high redshift galaxies. Absorbing systems that would otherwise go unnoticed are revealed through the Lyman-alpha forest, Lyman-limit, and damped Lyman-alpha systems, tracing the distribution of baryonic matter on large scales, and its chemical enrichment. We are living an exciting epoch with the advent of new instruments and facilities, on board of satellites and on the ground. Wide field and very sensitive integral field spectrographs are becoming available on the ground, such as MUSE at the ESO VLT. The giant E-ELT and TMT telescopes will foster a quantum leap in sensitivity and both spatial and spectroscopic resolution, to the point of being able, perhaps, to measure directly the acceleration of the Hubble flow. In space, the JWST will open new possibilities to study the Lyman-alpha emission of primordial galaxies in the near infrared. As long as the Hubble Space Telescope will remain available, the UV-restframe properties of nearby galaxies will be accessible to our knowledge. Therefore, this Saas-Fee course appears very timely and should meet the interest of many young researchers.
Publisher: Springer Nature
ISBN: 3662596237
Category : Science
Languages : en
Pages : 421
Book Description
The hydrogen Lyman-alpha line is of utmost importance to many fields of astrophysics. This UV line being conveniently redshifted with distance to the visible and even near infrared wavelength ranges, it is observable from the ground, and provides the main observational window on the formation and evolution of high redshift galaxies. Absorbing systems that would otherwise go unnoticed are revealed through the Lyman-alpha forest, Lyman-limit, and damped Lyman-alpha systems, tracing the distribution of baryonic matter on large scales, and its chemical enrichment. We are living an exciting epoch with the advent of new instruments and facilities, on board of satellites and on the ground. Wide field and very sensitive integral field spectrographs are becoming available on the ground, such as MUSE at the ESO VLT. The giant E-ELT and TMT telescopes will foster a quantum leap in sensitivity and both spatial and spectroscopic resolution, to the point of being able, perhaps, to measure directly the acceleration of the Hubble flow. In space, the JWST will open new possibilities to study the Lyman-alpha emission of primordial galaxies in the near infrared. As long as the Hubble Space Telescope will remain available, the UV-restframe properties of nearby galaxies will be accessible to our knowledge. Therefore, this Saas-Fee course appears very timely and should meet the interest of many young researchers.
International Workshop on Large Scale Structure in the Universe, Potsdam, 18-24 September 1994
Author: Jan P. Mucket
Publisher: World Scientific
ISBN: 9814532460
Category : Galaxies
Languages : en
Pages : 394
Book Description
Publisher: World Scientific
ISBN: 9814532460
Category : Galaxies
Languages : en
Pages : 394
Book Description
Lyman Alpha Forest and Damped Lyman Alpha Systems
Author: Varsha Purushottam Kulkarni
Publisher:
ISBN:
Category : Quasars
Languages : en
Pages : 472
Book Description
Publisher:
ISBN:
Category : Quasars
Languages : en
Pages : 472
Book Description