The Tully-Fisher Relation Provides a Method of Determining Distances to Galaxies

question 82

Multiple Choice

The Tully-Fisher relation provides a method of determining distances to galaxies by estimating the galaxy luminosity from the measurement of what parameter relating to the 21-centimeter atomic hydrogen radio emission line?

• A) Its position and Doppler shift
• B) The split between its two components
• C) Its width
• D) Its intensity

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Definitions:

Dose-Response Relationship

The relationship between the quantity of a drug or other exposure and the magnitude of the effect it has on an organism.

Predictive Validity

The extent to which a test or measurement can accurately forecast or predict future outcomes or behaviors.

Criterion Validity

The extent to which a test's results correlate with other measures or outcomes that are already accepted as reflecting the variable being tested.

Epidemiological

Relating to the study of the distribution and determinants of health and diseases in populations.