Lyman Imaging of High-Redshift Galaxies.III.New Observations of Four QSO Fields

Steidel, Charles C.; Pettini, Max; Hamilton, D.

doi:10.1086/117709

Cited by 240 publications

(281 citation statements)

References 28 publications

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“…where light is generated by stars) at high redshifts has seen a tremendous progress in the last years thanks to programs employing the Lyman break technique (cf. Steidel et al 1995Steidel et al , 1996Steidel et al , 1999, and projects like the Hubble Deep Field (HDF, Williams et al 1996). Steidel and collaborators (1996) have shown that on the order of a few percent of the galaxies at faint optical magnitudes (R ∼ 25) are actively star forming galaxies at redshift greater than 3.…”

Section: Star Forming Galaxies At High Redshiftmentioning

confidence: 99%

The most metal-poor galaxies

Kunth

Östlin

2000

Astronomy and Astrophysics Review

377

428

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Metallicity is a key parameter that controls many aspects in the formation and evolution of stars and galaxies. In this review we focus on the metal deficient galaxies, in particular the most metal-poor ones, because they play a crucial rôle in the cosmic scenery. We first set the stage by discussing the difficult problem of defining a global metallicity and how this quantity can be measured for a given galaxy. The mechanisms that control the metallicity in a galaxy are reviewed in detail and involve many aspects of modern astrophysics: galaxy formation and evolution, massive star formation, stellar winds, chemical yields, outflows and inflows etc. Because metallicity roughly scales as the galactic mass, it is among the dwarfs that the most metalpoor galaxies are found. The core of our paper reviews the considerable progress made in our understanding of the properties and the physical processes that are at work in these objects. The question on how they are related and may evolve from one class of objects to another is discussed. While discussing metal-poor galaxies in general, we present a more detailed discussion of a few very metal-poor blue compact dwarf galaxies like IZw18. Although most of what is known relates to our local universe, we show that it pertains to our quest for primeval galaxies and is connected to the question of the origin of structure in the universe. We discuss what QSO absorption lines and known distant galaxies tell us already? We illustrate the importance of star-forming metal-poor galaxies for the determination of the primordial helium abundance, their use as distance indicator and discuss the possibility to detect nearly metal-free galaxies at high redshift from Lyα emission.

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Section: Star Forming Galaxies At High Redshiftmentioning

confidence: 99%

The most metal-poor galaxies

Kunth

Östlin

2000

Astronomy and Astrophysics Review

377

428

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“…The discretization was performed considering the Lyman Break Method [Steidel, Hamilton, 1992;Steidel et al, 1995], based upon broad spectral features that can be easily identified. These include the Lyman Alpha Break and the Lyman Limits.…”

Section: Bzk Atrributes: (B-v)-(v-r) (V-r)-(r-i) (R-i)-(i-z)mentioning

confidence: 99%

Estimating Photometric Redshifts Using Genetic Algorithms

Miles

Freitas

Serjeant

2007

Applications and Innovations in Intelligent Systems XIV

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Photometry is used as a cheap and easy way to estimate redshifts of galaxies, which would otherwise require considerable amounts of expensive telescope time. However, the analysis of photometric redshift datasets is a task where it is sometimes difficult to achieve a high classification accuracy. This work presents a custom Genetic Algorithm (GA) for mining the Hubble Deep Field North (HDF-N) datasets to achieve accurate IF-THEN classification rules. This kind of knowledge representation has the advantage of being intuitively comprehensible to the user, facilitating astronomers' interpretation of discovered knowledge. The GA is tested against the state of the art decision tree algorithm C5.0 [Rulequest, 2005] in two datasets, achieving better classification accuracy and simpler rule sets in both datasets.

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“…The original U n GR-based colours of Steidel, Pettini & Hamilton (1995) have more recently been 'tuned' (see Adelberger et al 2004) to select galaxies at mean redshifts z = 3.0 (LBGs), 2.2 (BX galaxies) and 1.7 (BM galaxies), in each case with a redshift dispersion of about 0.3 (see Figure 1).…”

Section: Dwarf Ellipticals At High Redshiftsmentioning

confidence: 99%

Galaxies at high redshifts: where are the progenitors of today's dwarf ellipticals?

Pettini

2005

Proc. IAU

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Abstract. The epochs when many dwarf ellipticals were forming their stellar populations have recently become accessible to direct observation, as surveys at z = 1-5 have now uncovered thousands of galaxies. I briefly review the properties of various categories of high redshift galaxies in search of clues for possible links to today's galaxy populations. While much of the emphasis up to now has been on massive elliptical galaxies, with several groups claiming to have identified their progenitors with a variety of different techniques, dwarf galaxies have generally been overlooked-no doubt because the observational difficulties at high redshift are still considerable. Based on available data, it is possible that at least some of the 'Lyα emitters' and the damped Lyα systems may be on evolutionary paths which will transform them into the galaxies which are the subject of this meeting.

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Lyman Imaging of High-Redshift Galaxies.III.New Observations of Four QSO Fields

Cited by 240 publications

References 28 publications

The most metal-poor galaxies

The most metal-poor galaxies

Estimating Photometric Redshifts Using Genetic Algorithms

Galaxies at high redshifts: where are the progenitors of today's dwarf ellipticals?

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