Quasi-periodic Oscillation - Measuring Black Holes

Measuring Black Holes

QPOs can be used to determine the mass of black holes. The technique uses a relationship between black holes and the inner part of their surrounding disks, where gas spirals inward before reaching the event horizon. The hot gas piles up near the black hole and radiates a torrent of X-rays, with an intensity that varies in a pattern that repeats itself over a nearly regular interval. This signal is the QPO. Astronomers have long suspected that a QPO’s frequency depends on the black hole’s mass. The congestion zone lies close in for small black holes, so the QPO clock ticks quickly. As black holes increase in mass, the congestion zone is pushed farther out, so the QPO clock ticks slower and slower.

Read more about this topic:  Quasi-periodic Oscillation

Famous quotes containing the words measuring, black and/or holes:

    ... there is no way of measuring the damage to a society when a whole texture of humanity is kept from realizing its own power, when the woman architect who might have reinvented our cities sits barely literate in a semilegal sweatshop on the Texas- Mexican border, when women who should be founding colleges must work their entire lives as domestics ...
    Adrienne Rich (b. 1929)

    th’ other black and grave, wherewith each one
    Is checker’d all along,
    Humilitie:
    George Herbert (1593–1633)

    The danger lies in forgetting what we had. The flow between generations becomes a trickle, grandchildren tape-recording grandparents’ memories on special occasions perhaps—no casual storytelling jogged by daily life, there being no shared daily life what with migrations, exiles, diasporas, rendings, the search for work. Or there is a shared daily life riddled with holes of silence.
    Adrienne Rich (b. 1929)