First results from the Goddard High-Resolution Spectrograph - The Galactic halo and the Ly-alpha forest at low redshift in 3C 273

Morris, Simon L.; Weymann, R. J.; Savage, Blair D.; Gilliland, Ronald L.

doi:10.1086/186107

Cited by 115 publications

(130 citation statements)

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“…To the surprise of many, the first studies with HST of low redshift (z < 1.5) Lyα lines (Bahcall et al 1991, Morris et al 1991, Impey et al 1996 (see also the paragraph on the low z Lyα forest below) have discovered more absorption systems than expected from a naive extrapolation of any of the high z power law exponents. Moreover, the low γ = 0.48 ± 0.62 valid from z ∼ 0 to z ∼ 1 gives a dN /dz that is consistent with a constant comoving density of objects.…”

Section: Redshift Evolution Of the Lyman Alpha Forestmentioning

confidence: 99%

The Lyman Alpha Forest in the Spectra of Quasistellar Objects

Rauch

1998

Annu. Rev. Astron. Astrophys.

456

325

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Observations of redshifted Lyman α (Lyα) forest absorption in the spectra of quasistellar objects (QSOs) provide a highly sensitive probe of the distribution of gaseous matter in the universe. Over the past two decades, optical spectroscopy with large ground-based telescopes, and more recently ultraviolet (UV) spectroscopy from space, have yielded a wealth of information on what appears to be a gaseous, photoionized intergalactic medium (IGM), partly enriched by the products of stellar nucleosynthesis, residing in coherent structures over many hundreds of kiloparsecs.Recent progress with cosmological hydro-simulations based on hierarchical structure formation models has led to important insights into the physical structures giving rise to the forest. If these ideas are correct, a truly inter-and protogalactic medium [at high redshift (z ∼ 3), the main repository of baryons] collapses under the influence of dark matter gravity into flattened or filamentary structures, which are seen in absorption against background QSOs. With decreasing redshift, galaxies forming in the denser regions may contribute an increasing part of the Lyα absorption cross section. Comparisons between large data samples from the new generation of telescopes and artificial Lyα forest spectra from cosmological simulations promise to become a useful cosmological tool.

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Section: Redshift Evolution Of the Lyman Alpha Forestmentioning

confidence: 99%

The Lyman Alpha Forest in the Spectra of Quasistellar Objects

Rauch

1998

Annu. Rev. Astron. Astrophys.

456

325

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“…The several generations of UV spectrographs on the Hubble Space Telescope have vastly increased the number of Galactic as well as extragalactic sight lines probed for their neutral or ionized gas. For example, these observations uncovered the existence and properties of low-redshift Lyman-α forest clouds, as well as the covering fractions, element abundances, temperatures, and kinematics of the circumgalactic medium (CGM; e.g., Morris et al (1991); Bahcall et al (1993); Savage & Sembach (1996) and references therein; Kulkarni et al (2005); Lehner et al (2013); Tumlinson et al (2013); Som et al (2015); Werk et al (2016)). Naturally, these observations provide crucial constraints on models of galaxy evolution, including the effect of outflows and inflows.…”

Section: Introductionmentioning

confidence: 99%

Atomic Data Revisions for Transitions Relevant to Observations of Interstellar, Circumgalactic, and Intergalactic Matter

Cashman

Kulkarni

Kisielius

et al. 2017

ApJS

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Measurements of element abundances in galaxies from astrophysical spectroscopy depend sensitively on the atomic data used. With the goal of making the latest atomic data accessible to the community, we present a compilation of selected atomic data for resonant absorption lines at wavelengths longward of 911.753Å (the H I Lyman limit), for key heavy elements (heavier than atomic number 5) of astrophysical interest. In particular, we focus on the transitions of those ions that have been observed in the Milky Way interstellar medium (ISM), the circumgalactic medium (CGM) of the Milky Way and/or other galaxies, and the intergalactic medium (IGM). We provide wavelengths, oscillator strengths, associated accuracy grades, and references to the oscillator strength determinations. We also attempt to compare and assess the recent oscillator strength determinations. For about 22% of the lines that have updated oscillator strength values, the differences between the former values and the updated ones are 0.1 dex. Our compilation will be a useful resource for absorption line studies of the ISM, as well as studies of the CGM and IGM traced by sight lines to quasars and gamma-ray bursts. Studies (including those enabled by future generations of extremely large telescopes) of absorption by galaxies against the light of background galaxies will also benefit from our compilation.

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“…H i mann et al 1998), followed by more sensitive discovery programs with the Goddard High Resolution Spectrometer (GHRS) and Space Telescope Imaging Spectrograph (STIS; Morris et al 1991;Impey, Petry, & Flint 1999;Tripp, Lu, & Savage 1998) extending to somewhat lower equivalent width limits (W ≥ mÅ at ). Finally, in a large (31 sight line) sys-50-100 z Շ 0.3 tematic study, Penton, Shull, & Stocke (2000a, 2002, Penton, Stocke, & Shull (2000b), and S. V. Penton, J. M. Shull, & J. T. Stocke (2002, in preparation) have used GHRS and STIS at medium resolution (∼20 km s…”

Section: Introductionmentioning

confidence: 99%

The Local L[CLC]y[/CLC]α Forest: Absorbers in Galaxy Voids

McLin

Stocke

Weymann

et al. 2002

The Astrophysical Journal

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We have conducted pointed redshift surveys for galaxies in the direction of bright active galactic nuclei whose appear to be truly intergalactic, rather than part of galaxies or their halos. Since we and others have discovered no galaxies in voids, the only baryons detected in the voids are in the Lya "clouds." Using a photoionization model for these clouds, the total baryonic content of the voids is of the mean baryon density. 4.5% ‫ע‬ 1.5%

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First results from the Goddard High-Resolution Spectrograph - The Galactic halo and the Ly-alpha forest at low redshift in 3C 273

Cited by 115 publications

References 0 publications

The Lyman Alpha Forest in the Spectra of Quasistellar Objects

The Lyman Alpha Forest in the Spectra of Quasistellar Objects

Atomic Data Revisions for Transitions Relevant to Observations of Interstellar, Circumgalactic, and Intergalactic Matter

The Local L[CLC]y[/CLC]α Forest: Absorbers in Galaxy Voids

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