The HI environment of nearby Lyman-alpha absorbers

Cover of: The HI environment of nearby Lyman-alpha absorbers |

Published by National Aeronautics and Space Administration, National Technical Information Service, distributor in [Washington, DC, Springfield, Va .

Written in English

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Subjects:

  • Lyman alpha radiation.,
  • Absorption spectra.,
  • Dwarf galaxies.,
  • Spiral galaxies.,
  • Radio astronomy.,
  • Galactic radiation.

Edition Notes

Book details

StatementJ.H. van Gorkom ... [et al.].
Series[NASA contractor report] -- NASA-CR-204571., NASA contractor report -- NASA CR-204571.
ContributionsVan Gorkom, J. H., United States. National Aeronautics and Space Administration.
The Physical Object
FormatMicroform
Pagination1 v.
ID Numbers
Open LibraryOL15486966M

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Get this from a library. The HI environment of nearby Lyman-alpha absorbers. [J H Van Gorkom; United States. National Aeronautics and Space Administration.;]. The Environment The HI environment of nearby Lyman-alpha absorbers book Lyman- alpha Absorbers in the Sight Line toward 3C University of Hawaii, Honolulu, HI R.

T errile. and 2 bright. Lyman-alpha Astrophysics and its Application The Hi Lyman-alpha emission line (Ly) is the de facto spectroscopic feature of evolving galaxies in the high-redshift universe [1]. Reprocessing roughly 40 per cent of the intrinsic ionizing energy (h > 1 Ryd) into a single high-contrast feature, Ly surveys are able.

In physics, the Lyman-alpha line, sometimes written as Ly-α line, is a spectral line of hydrogen, or more generally of one-electron ions, in the Lyman series, emitted when the electron falls from the n = 2 orbital to the n = 1 orbital, where n is the principal quantum hydrogen, its wavelength of angstroms ( nm or 67 × 10 −7 m), corresponding to a.

The spatial and kinematic distribution of warm gas in and around the Coma Cluster is presented through observations of Lyman-alpha absorbers using background QSOs.

Updates to the Lyman-alpha absorber distribution found in Yoon et al. () for the Virgo Cluster are also presented. At R_vir of Coma we identify 14 Lyman-alpha absorbers (N_HI = 10^{} cm^-2) Cited by:   Abstract.

We discuss inferences of a special type of Galactic chemical evolution models for damped Lyman \(\alpha\) absorber systems (DLAS) at intermediate and high redshift. The agreement between model predictions and the observed properties of DLAS strongly depends on the existence of a dust extinction bias in the DLAS sample.

We find line-of-sight velocity correlations of up to km/s between Ly-alpha absorbers with log N(HI)>= and 45 galaxies taken from the literature and unpublished data at 0. We present composite spectra constructed from a sample ofLyman-alpha (Lya) forest absorbers at redshifts Cited by: Modeling Damped Lyman-alpha Absorbers Astronomy Spring In a recent paper, Prochaska & Wolfe () present a kinematic model of damped Lyman-alpha absorbers as thick rotating disks of individual clouds.

Their model treats the random velocities of the clouds and the thickness of the disk as independent parameters. History. The Lyman-alpha forest was first discovered in by astronomer Roger Lynds in an observation of the quasar 4C Quasar 4C was the farthest object observed to that date, and Lynds noted an unusually large number of absorption lines in its spectrum.

He suggested that most of the absorption lines were all due to the same Lyman-alpha transition. The strong and broad emission peak is Lyman alpha, which is almost chopped in half by the onset of the Lyman alpha forest in the high-redshift quasar.

At low redshift, 3C shows only a handful (but distinctly more than zero) Lyman alpha absorbers, including the strong and broad absorption from its light intercepting the disk of a foreground. Lyman Alpha Forest ENCYCLOPEDIA OF ASTRONOMY AND STROPHYSICS Figure 1. High resolution spectrum of the Lyα forest part of a redshift QSO, taken with the HIRES spectrograph on the Keck 10 m telescope in Hawaii.

The plot shows the flux of the QSO in arbitrary units versus the observed wavelength in units ofAngstroms. TheFile Size: KB. 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. @article{osti_, title = {On the Origin of the High Column Density Turnover in the HI Column Density Distribution}, author = {Erkal, Denis and Gnedin, Nickolay Y.

and Kravtsov, Andrey V.}, abstractNote = {We study the high column density regime of the HI column density distribution function and argue that there are two distinct features: a turnover at NHI ~ 10^21.

The damped Lyman-alpha (DLA; log N HI ⩾ ) and sub-damped Lyman-alpha (sub-DLA; ⩽ log N HI Cited by: Abstract. We probe the chemical evolution of DLAs by studying low-z DLAs for which very little information exists. We use Zn to get the metallicity (since it is almost undepleted on dust), and relative abundances of other elements to study nucleosynthesis and dust-depletion (Kulkarni et al.to be submitted).Cited by: 3.

Hello everyone. We observe the so-called Lyman-alpha forest in the spectrum of distant quasars and it is said that these multiple absorption lines are due to the presence of intergalactic HI clouds that absorb light at the wavelenght of A, the Lyman-alpha transition.

My question is the. Finally, the HI environment of the massive Great Attractor complex is examined. Stocke, John (Univ. of Colorado/Boulder) The Local Ly alpha Forest: HI in Nearby Intergalactic Space John T. Stocke Detecting H I using redshifted Ly alpha absorption lines is ~10^7 times more sensitive than using the 21 cm line.

The Lyman-alpha "forest" are absorption lines in a quasar spectrum created by all of the gases along the billions of light years its energy has traversed. True The younger the universe was, the more abundant quasars were, according to our deep surveys. The damped systems are a class of quasar absorption line (QAL) system, specifically those QAL's with HI column density, N(HI) > 2 ×10 20 cm On the right here is a fine example.

The red line describes the fit to the damped system; note in particular the damping wings of the profile. using a cosmological simulation) for f(N HI) -- the number of absorption lines per unit redshift per hydrogen column, N HI.

The plotted N HI correspond to systems with densities that are more than a hundred times larger than probed with the Lyman-alpha forest. The highlighted regions are the constraints on f(N HI) at z=4 from quasar absorption observations.

Damped Lyman alpha systems or Damped Lyman alpha absorption systems is a term used by astronomers for concentrations of neutral hydrogen gas that are detected in the spectra of quasars – a class of distant Active Galactic are defined to be systems where the column density (density projected along the line of sight to the quasar) of hydrogen is larger.

Gas and Galaxy Evolution: A Conference in Honor of the 20th Anniversary of the VLA Volume: Year: View this Volume on ADS: Editors: Hibbard, John E.; Rupen, Michael; van Gorkom, Jacqueline H. ISBN: eISBN: Electronic access to books and articles is now available to purchase. Volume eAccess.

The Lyman alpha forest can be used to trace this re-ionization of the universe. Figure 2: The spectrum of quasar ULAS J+, overlaid with a template quasar spectrum in red. Many of the quasar emission lines are identified, including Mg II, which is used to estimate the mass of the supermassive black hole believed to be at the center of.

The associated metal absorption lines from the strongest absorption lines, the damped Lyman alpha absorbers (DLAs), allow us to trace the metallicity of galaxies back to redshifts z>5. Typical metallicities range from % solar metallicities with a huge scatter at any given redshift.

absorbers were thought of as a distinct class of objects (Sargent et al. ), differing in their properties from both galaxies and other absorption line classes, such as metal line systems and the higher column density Lyman limit and damped Lyfi absorption systems.

Although some of these distinctions have become blurred, the. The composite Lyman-alpha time series has been updated to include the latest versions of the TIMED SEE and SORCE SOLSTICE solar irradiance measurements of the bright H I nm emission. These TIMED and SORCE data are used in the present time range and are scaled to match the UARS reference level as discussed by Woods et al.

[JGR, ]. X-RAY AND LYMAN-ALPHA EMISSION FROM THE SUN AS MEASURED FROM THE NRL SR-1 SATELLITE [R.W., et al Kreplin] on *FREE* shipping on qualifying : Kreplin, R.W., et al.

SSALyman-alpha blob 1 (LAB-1 for short), one of the largest LABs known, was the very first such object to be discovered — in This gigantic cloud is aboutlight-years across. In extragalactic astronomy, a Lyman-alpha blob (LAB) is a huge concentration of gas emitting the Lyman-alpha emission line, a spectral line of hydrogen, or more generally of one-electron ions, in the Lyman series.

Lyman-alpha blobs are some of the largest known individual objects in. This particular space blob, named SSALyman-alpha Blob 1 (LAB-1), is the largest of its kind.

It measures aboutlight-years across, or three times the size of the Milky Way : Hanneke Weitering. Distant quasars appear to be absorbed by many more Lyman-alpha clouds than nearby quasars, indicating a Lyman-alpha thicket early in our universe.

The above image depicts one possible computer realization of how Lyman-alpha clouds were distributed at a redshift of 3. Each side of the box measures 30 million light-years across. Then line width (Doppler parameter b (= 2)), column density N(HI), and redshift z of an absorption line are the basic observables.

The statistics of the Ly forest from high resolution studies largely have been cast in terms of the distribution functions of these three quantities and their correlations. The main advantage of the high resolution.

[/caption] It’s called a Lyman-alpha blob and it’s one of the largest known single objects in the Universe. It first made its presence known in the year and we know it’s located some The interstellar radiation field of high-redshift damped Lyman-alpha absorbers: Kaushal Buch: ASI_ GMRT, NCRA-TIFR: Initial Developments in the Design and Implementation of FPA Beamformer for the Expanded GMRT: Kaushal Sharma: ASI_ IUCAA, Pune: Kaustav Mitra: ASI_ Presidency University, Kolkata.

We investigate the properties of the Lα absorption lines in the high resolution spectra of nine quasars, B2 +, PKSQQPHLPKSPKS +, PKS and PKS + Their emission line redshift range is ⩽ z em ⩽ ; a total of Lα absorption lines cover the range ⩽ z abs ⩽ Cited by: 4.

since the electron is de-exited from 1(st) exited state (i.e n = 2) to ground state (i.e n = 1) for first line of Lyman series. Since the atomic number of Hydrogen is 1. The first emission line in the Lyman series corresponds to the electron dropping from n = 2 to n = 1.

For a positive wavelength, we set the initial as n = 1 and final as n = 2. “Damped Lyman Alpha Systems” by Wolfe, Arthur M., Gawiser, E. and Prochaska, Jason X. Jean P. Walker Rutgers University Galaxy Formaon Seminar. The building blocks of galaxies: a galaxies toolkit.

Basic idea here is to communicate some of the methods that people use to study different components of galaxies. This is a very active field, so it is hard to give any final results. The rare, ethereal objects, first seen in the s, came to be known as Lyman-alpha blobs (Lab), their place instantly secured among the Author: Ian Sample.

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This guide, a continual work in progress like our other guides, aims to provide the context necessary to understand much of the spectral jargon in scientific papers on the arXiv. This page will give an overview of how spectroscopy works and what spectral lines are frequently observed by astronomers.List of approved WSRT MFFE projects.

Semester 04A () - Semester 12B () Note: Paper copies of all WSRT proposals prior to are stored in the control building at Westerbork. People wishing to look at proposals prior to for historical reasons, can arrange a visit there.

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