New extremely X-ray-weak blazar discovered

Astronomers from Italy and Spain have detected a new blazar by analyzing data from two astronomical surveys. The newly found object, designated DESJ014132.4-542749.9, turns out to be an extremely X-ray-weak blazar at high ...

Gamma-ray blazars in the sky

When the supermassive black holes at the center of galaxies accrete material, they can eject powerful jets of charged particles at speeds approaching that of light. These particles in turn emit radiation across the electromagnetic ...

Luminous gamma-ray flare detected from the blazar DA 193

An international group of astronomers has detected an intense and extremely luminous gamma-ray flare from one of high-redshift blazars known as DA 193. The new detection, reported in a paper published December 18 on arXiv.org, ...

Blazar's brightness cycle confirmed by NASA's Fermi mission

A two-year cycle in the gamma-ray brightness of a blazar, a galaxy powered by a supermassive black hole, has been confirmed by 10 years of observations from NASA's Fermi Gamma-ray Space Telescope. The findings were announced ...

Blazar LBQS 1319+0039 detected in hard X-rays

An international team of astronomers reports the detection of the blazar LBQS 1319+0039 in hard X-rays using NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) space telescope. The finding, updating knowledge about this ...

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Blazar

A blazar (blazing quasi-stellar object) is a very compact quasar (quasi-stellar object) associated with a presumed supermassive black hole at the center of an active, giant elliptical galaxy. Blazars are among the most energetic phenomena in the universe and are an important topic in extragalactic astronomy.

Blazars are members of a larger group of active galaxies that host active galactic nuclei (AGN). A few rare objects may be "intermediate blazars" that appear to have a mixture of properties from both optically violent variable (OVV) quasars and BL Lac objects. The name "blazar" was originally coined in 1978 by astronomer Edward Spiegel to denote the combination of these two classes.

Blazars are AGN with a relativistic jet that is pointing in the general direction of the Earth. We observe "down" the jet, or nearly so, and this accounts for the rapid variability and compact features of both types of blazars. Many blazars have apparent superluminal features within the first few parsecs of their jets, probably due to relativistic shock fronts.

The generally accepted picture is that OVV quasars are intrinsically powerful radio galaxies while BL Lac objects are intrinsically weak radio galaxies. In both cases the host galaxies are giant ellipticals.

Alternative models, for example, gravitational microlensing, may account for a few observations of some blazars which are not consistent with the general properties.

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