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verification. (January 2014) |
The X-factor in astrophysics, often labeled XCO, is an empirically determined proportionality constant which converts carbon monoxide (CO) emission line brightness to molecular hydrogen (H2) mass.
The term X-factor was coined in a 1983 paper titled "Gamma-rays from atomic and molecular gas in the first galactic quadrant" and published in The Astrophysical Journal. [1] [2]
Calibrating XCO requires an independent method of determining the amount of molecular hydrogen in a given astrophysical region. While direct emission from molecular hydrogen is difficult to observe, there are other ways of inferring molecular hydrogen mass, outlined below. [3]
This article needs additional citations for
verification. (January 2014) |
The X-factor in astrophysics, often labeled XCO, is an empirically determined proportionality constant which converts carbon monoxide (CO) emission line brightness to molecular hydrogen (H2) mass.
The term X-factor was coined in a 1983 paper titled "Gamma-rays from atomic and molecular gas in the first galactic quadrant" and published in The Astrophysical Journal. [1] [2]
Calibrating XCO requires an independent method of determining the amount of molecular hydrogen in a given astrophysical region. While direct emission from molecular hydrogen is difficult to observe, there are other ways of inferring molecular hydrogen mass, outlined below. [3]