quasar Hear it!

quasar Definition

☆ qua·sar (kwā′zär′, -sär′)

noun

any of a number of starlike celestial objects that emit immense amounts of light and, often, radio waves, characterized by having spectral lines with very large redshifts: quasars are thought to be the most distant and oldest observable objects in the universe

Etymology: < quas(i-stell)ar (radio source)

quasar Usage Examples

Converse of object

  • obscure: Several strong candidates for Type 2, or obscured quasars have been discovered.
  • know: An example of this can be seen in the spectrum of the most distant quasar currently known.
  • find: Finding the powerful quasars responsible for the X-ray background radiation.
  • detect: The total number of ROSAT detected radio quasars from the above three sources is 654 objects.
  • observe: Further evidence comes from astronomical observation - astronomers look into the past when they look into space and have been measuring and observing quasars.
  • call: The objects called quasars are very strong point like radio sources, which can, like all radio objects, be detected in daylight.

Adjective modifier

  • distant: Most types of cosmic object known to exist, from dwarf stars to the most distant quasars, are known to emit X-rays.
  • bright: It is a suggestive coincidence that the space density of bright optical quasars also reached a peak sometime around z = 2-3.
  • high: The low and high redshift quasars are found very similar in their emission characteristics, although differences exist.
  • several: In several quasars, small, discrete sources have been found that change position from one observation to the next.
  • nearby: At a distance of 1 billion light-years, Mrk 205 is a relatively nearby quasar.

Modifies a noun

  • absorption: The nub of the lecture was work on the very high-resolution spectroscopy of quasar absorption lines.
  • line: The nub of the lecture was work on the very high-resolution spectroscopy of quasar absorption lines.
  • survey: It has also been involved with quasar surveys and more recently the discovery of over 20 planets around other stars.
  • activity: Possible links between these black holes and quasar activity early in the history of the Universe.

Noun used with modifier

  • redshift: The low and high redshift quasars are found very similar in their emission characteristics, although differences exist.
  • radio-loud: Almost one quarter of these are members of a previously unknown class of X-ray bright, flat spectrum, radio-loud quasars.
  • high-redshift: Some astronomers supported this point of view, and have sought evidence for physical associations between high-redshift quasars and low-redshift normal galaxies.
  • radio: The total number of ROSAT detected radio quasars from the above three sources is 654 objects.
  • background: HI can be studied in absorption against background quasars out to z 4 with the HIA.