Equation 12 · Part 2 · A Neutron Star Is a Redshift Standard
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=
What this part means
The expressions on both sides represent the same quantity under the stated assumptions.
Its job in the formula
The equals sign connects the complete expression on the left with the complete expression on the right. Both sides must have compatible units.
Full expression→=→Article meaning
The passage around this formula
— a function of the star’s compactness alone, so that whatever fraction of a percent of uncertainty NICER puts on M and R propagates directly into the redshift. The paper works through six NICER-mapped pulsars this way, and two of them mark the range worth remembering. PSR J0740+6620, the most massive precisely-timed neutron star known, comes in at roughly 2.07\, with a radio-timing mass fixed independently by Shapiro delay to 2.080.07\, [ 4 ] , giving a compactness near 0.25 and a surface redshift 0.40 — the deepest gravitational potential in the sample, though also, because its radius is the harder-measured half of the pair, the least precisely known redshift, at…
Learn the underlying idea
An equals sign says that the expression on its left and the expression on its right have the same value under the stated definitions and assumptions.
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Sources cited in the surrounding passage
- [4] Refined Mass and Geometric Measurements of the High-mass PSR J0740+6620 ↗
- [3] A NICER View of the Nearest and Brightest Millisecond Pulsar: PSR J0437-4715 ↗
These citations provide research context; check each source for the exact claim it supports.