Why Has the 21 Cm Emission Line Been Especially Useful

question 32

Multiple Choice

Why has the 21 cm emission line been especially useful for studying the structure of the Milky Way galaxy?

• A)Stars emit very strongly at 21 cm
• B)The 21 cm radiation travels to us at the speed of light
• C)Twenty-one cm emission is produced only in the core of the galaxy
• D)Twenty-one cm radiation is unaffected by interstellar dust

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Definitions:

Consolidation

The process of combining multiple entities, assets, or financial statements into a single entity or financial statement.

Acquisition

The process of purchasing another company to gain control, typically through a buyout or merger.

Merger

The combination of two or more businesses under one ownership in which all but one legal entity ceases to exist, and the combined organization continues under the name of the surviving firm. When the surviving firm acquires the stock of the others, the transaction can be called an acquisition. A merger is friendly if it has the approval and support of the acquired (target) firm’s management. It is unfriendly if the target’s management resists. The term merger tends to be used loosely to refer to any business combination.

Legal Entity

An organization or business that is recognized by law as having a distinct legal existence, separate from its owners.