damped Lyman-alpha systems
E451580
Damped Lyman-alpha systems are high-column-density neutral hydrogen gas clouds observed in quasar spectra, serving as key probes of the interstellar medium and chemical evolution of galaxies in the early universe.
All labels observed (1)
| Label | Occurrences |
|---|---|
| damped Lyman-alpha systems canonical | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T4553108 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: damped Lyman-alpha systems Context triple: [MIKE, scienceTarget, damped Lyman-alpha systems]
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A.
Physics of the Interstellar and Intergalactic Medium
Physics of the Interstellar and Intergalactic Medium is a comprehensive graduate-level textbook that explains the physical processes governing gas, dust, radiation, and magnetic fields in the space between and among galaxies.
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B.
Galactic thin disk
The Galactic thin disk is the relatively flat, rotating component of the Milky Way where most of its young to middle-aged stars, gas, and spiral arms are concentrated.
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C.
CANDELS survey
The CANDELS survey is a major Hubble Space Telescope deep-imaging program designed to study the formation and evolution of galaxies across cosmic time.
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D.
Cosmic Dawn Center (DAWN)
The Cosmic Dawn Center (DAWN) is a research center focused on studying the formation and evolution of the earliest galaxies, stars, and cosmic structures in the universe.
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E.
The Large-Scale Structure of the Universe
The Large-Scale Structure of the Universe is a foundational cosmology book by James Peebles that systematically develops the theory and observations of how matter is distributed on the largest cosmic scales.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: damped Lyman-alpha systems Target entity description: Damped Lyman-alpha systems are high-column-density neutral hydrogen gas clouds observed in quasar spectra, serving as key probes of the interstellar medium and chemical evolution of galaxies in the early universe.
-
A.
Physics of the Interstellar and Intergalactic Medium
Physics of the Interstellar and Intergalactic Medium is a comprehensive graduate-level textbook that explains the physical processes governing gas, dust, radiation, and magnetic fields in the space between and among galaxies.
-
B.
Galactic thin disk
The Galactic thin disk is the relatively flat, rotating component of the Milky Way where most of its young to middle-aged stars, gas, and spiral arms are concentrated.
-
C.
CANDELS survey
The CANDELS survey is a major Hubble Space Telescope deep-imaging program designed to study the formation and evolution of galaxies across cosmic time.
-
D.
Cosmic Dawn Center (DAWN)
The Cosmic Dawn Center (DAWN) is a research center focused on studying the formation and evolution of the earliest galaxies, stars, and cosmic structures in the universe.
-
E.
The Large-Scale Structure of the Universe
The Large-Scale Structure of the Universe is a foundational cosmology book by James Peebles that systematically develops the theory and observations of how matter is distributed on the largest cosmic scales.
- F. None of above. chosen
Statements (48)
| Predicate | Object |
|---|---|
| instanceOf |
astrophysical object
ⓘ
neutral hydrogen absorber ⓘ quasar absorption line system ⓘ |
| causes | depletion of refractory elements onto dust grains ⓘ |
| constrains |
cosmic evolution of neutral hydrogen density
ⓘ
nucleosynthesis yields of early generations of stars ⓘ |
| contains | dust ⓘ |
| contrastedWith |
Lyman-alpha forest absorbers
NERFINISHED
ⓘ
Lyman-limit systems NERFINISHED ⓘ |
| definedBy | high-column-density neutral hydrogen gas ⓘ |
| hasAbbreviation | DLA NERFINISHED ⓘ |
| hasAlternativeName | damped Lyα system ⓘ |
| hasCosmologicalSignificance | dominant reservoir of neutral gas at high redshift ⓘ |
| hasEnvironment | often associated with faint or low-luminosity galaxies ⓘ |
| hasKinematics |
multiple narrow velocity components
ⓘ
velocity widths of tens to hundreds of km s^-1 ⓘ |
| hasLowerColumnDensityLimitThan | sub-damped Lyman-alpha systems ⓘ |
| hasLymanAlphaProfile | damped wings ⓘ |
| hasMetallicity |
sub-solar metallicity
ⓘ
typically 1/100 to 1/3 solar ⓘ |
| hasNeutralHydrogenColumnDensity |
> 10^20.3 atoms cm^-2
ⓘ
> 2×10^20 atoms cm^-2 ⓘ |
| hasObservationTechnique | high-resolution optical and UV spectroscopy ⓘ |
| hasOpticalDepth | optically thick at the Lyman limit ⓘ |
| hasPhysicalComponent | neutral hydrogen gas cloud ⓘ |
| hasRedshiftRange | z ~ 0–5 and above ⓘ |
| hasSelectionMethod | absorption-selected in background source spectra ⓘ |
| hasTypicalRedshiftRange | high redshift (z ≳ 2) ⓘ |
| locatedIn |
circumgalactic medium
ⓘ
interstellar medium of galaxies ⓘ |
| measuredBy |
Voigt profile fitting of Lyman-alpha line
ⓘ
curve-of-growth analysis of metal lines ⓘ |
| observedIn |
gamma-ray burst afterglow spectrum
ⓘ
quasar spectrum ⓘ |
| probes |
chemical evolution of galaxies
ⓘ
cosmic neutral gas content ⓘ interstellar medium in high-redshift galaxies ⓘ star-formation fuel in the early universe ⓘ |
| relatedTo | sub-damped Lyman-alpha system ⓘ |
| showsSpectralFeature |
Lyman series absorption lines
ⓘ
damped Lyman-alpha absorption line ⓘ metal absorption lines ⓘ |
| traces | neutral gas reservoir for star formation ⓘ |
| usedAs |
probe of galaxy formation
ⓘ
probe of large-scale structure ⓘ tracer of cosmic metal enrichment ⓘ |
| usedToMeasure |
abundances of elements such as Fe, Si, Zn, S
ⓘ
primordial deuterium abundance in some cases ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: damped Lyman-alpha systems Description of subject: Damped Lyman-alpha systems are high-column-density neutral hydrogen gas clouds observed in quasar spectra, serving as key probes of the interstellar medium and chemical evolution of galaxies in the early universe.
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.
subject surface form:
MIKE