Sentences with phrase «fermi blazars»

This event was so exceptional that for a few days this object was the brightest blazar observed until now.

In the second half of last year the blazar CTA 102, which is 7,600 million light years from Earth, brightened considerably, drawing the attention of all the astronomers who specialise in this kind of objects.

A blazar, a galaxy that kicks out fluctuating X-rays, might also have been responsible, but blazars are easily identified by their strong radio emissions, something not apparent in this source (Nature, DOI: 10.1038 / nature08083).

Black - hole - powered galaxies called blazars are the most common sources detected by NASA's Fermi Gamma - ray Space Telescope.

The infrared / gamma - ray connection led the authors to search for new blazar candidates among WISE infrared sources located within the positional uncertainties of Fermi's unidentified gamma - ray objects.

Astronomers suspect many of these are blazars, but there isn't enough information to classify them.

At the heart of a blazar lies a supersized black hole with millions of times the sun's mass surrounded by a disk of hot gas and dust.

In 2011, Massaro, D'Abrusco and their colleagues began using WISE data to investigate Fermi blazars.

They say the electrons, protons and other particles accelerated in blazar jets leave a specific «fingerprint» in the infrared light they emit.

A blazar appears bright to Fermi for two reasons.

The relationship effectively connects the dots for blazars across an enormous swath of the electromagnetic spectrum.

«NASA's WISE, Fermi missions reveal a surprising blazar connection.»

Francesco Massaro at the University of Turin in Italy and Raffaele D'Abrusco at the Harvard - Smithsonian Center for Astrophysics in Cambridge, Massachusetts, show for the first time that the mid-infrared colors of blazars in WISE data correlate to an equivalent measurement of their gamma - ray output.

«We found that when we plotted Fermi blazars by their WISE colors in a particular way, they occupied a distinctly different part of the plot than other extragalactic gamma - ray sources.»

The discovery, which was accomplished by comparing data from NASA's Wide - field Infrared Survey Explorer (WISE) and Fermi Gamma - ray Space Telescope, has enabled the researchers to uncover dozens of new blazar candidates.

They could have emerged from gamma - ray bursts, mysterious and short - lived cataclysms that briefly rank as the brightest objects in the universe; shock waves from exploding stars; or so - called blazars, jets of energy powered by supermassive black holes.

The High Altitude Water Cherenkov observatory has released its first map of the high - energy sky, catching pulsars, supernova remnants and blazars switching on and off

Gamma rays emanate from the most powerful and mysterious phenomena in the universe — quasars, supernovae, and the black hole - powered infernos called blazars.

Related sites Abstract of paper, with link to full text Chandra X-ray Observatory FUSE satellite, used in similar studies of lower - temperature gas Observations of Markarian 421 blazar Shull's home page

Astronomer Fabrizio Nicastro of the Harvard - Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and his colleagues monitored the galaxy Markarian 421, which contains a «blazar» — an active black hole that aims powerful jets of energy toward Earth.

Partially dimmed x-rays (dips in graph) from a flaring blazar (right) reveal two filaments of hot, diffuse matter in the vast spaces between galaxies.

It so happens that there is a galaxy roughly half way between Earth and the blazar, which is billions of light years away.

Fermi has shown that much of this light arises from unresolved gamma - ray sources, particularly galaxies called blazars, which are powered by material falling toward gigantic black holes.

Looking at a distant galaxy: the radio chart (left) shows the image of the blazar PKS 1830 - 211 distorted by the gravitational lens effect.

In a detailed analysis of high - energy EGB gamma rays, published April 14 in Physical Review Letters, Ajello and his team show that blazars and other discrete sources can account for nearly all of this emission.

This is a blazar — a rare case in which one of the two jets happens to be directed towards Earth so that the astronomers look directly into the jet along the longitudinal axis.

PKS 1830 - 211 thus appears in the sky as two images; and these images are brighter than the blazar would be without this lens effect.

It turns out that blazars are powered surprisingly like the exhausts of jet engines, albeit on a cosmic scale, says astronomer and lead author Alan Marscher of Boston University.

The light of the blazar behind it passes through this space well and takes a detour — as if it were passing through a lens.

J1415 +1320 is what's known as a blazar, a bright galaxy with a gluttonous supermassive black hole at its center (SN: 3/4/17, p. 13).

Astronomers had already recorded intensity flare ups in the radio region which originated from events in the blazar.

The detail on the right is a simulation of the micro-gravitational lens effect in the gamma ray region; direct observation of the orange ring — it also represents images of the blazar — is not possible due to its small size.

This behaviour and further findings from observations can be best explained with an interesting assumption: Although the brightness variations in the gamma ray region also originate from the flare ups in the blazar, they are amplified to different degrees by the gravitational lens effect of individual stars in the foreground galaxy.

The galaxy is among about 1,800 blazars that Readhead and his team have observed twice a week since 2008.

Now, Readhead and his colleagues argue that they're seeing the blazar's black hole emit tiny burps of plasma, magnified hundreds of times by a new kind of gravitational lens.

Instead of streaming out of a metal casing and turbine, a blazar's jets «are confined and focused by coiled magnetic fields originating near the [supermassive] black hole.»

Bright spots in the map include the Crab Nebula, which hosts a radiation - spewing stellar corpse called a pulsar, and several blazars, violent active galaxies where colossal black holes accelerate particles to more than 99 % the speed of light.

Blazars — found in the centers of some galaxies — and gamma - ray bursts are two identified wellsprings of these high - energy rays.

Blazars periodically flare when the supermassive black holes in some active galaxies» cores fill with dust and gas, releasing massive amounts of energy.

«These blazars have jets that are like fountains.

«Blazars are one type of active galaxy,» said Marco Ajello, a professor of physics and astronomy and Paliya's advisor.

«How do blazars behave at, say, radio frequencies?

However, rather than emitting violent bursts of gamma - ray radiation, like blazars, Seyfert galaxies are known for their strong ultra-violet emissions.

«It was unexpected — we have only seen that kind of gamma ray emission from blazars,» said Dieter Hartmann, a professor of physics and astronomy and co-author of the study.

«When these four sources were discovered, people speculated that they could be blazars.

Observations of blazars by NASA's Fermi Gamma Ray Telescope spacecraft for the first time detected that gamma rays from distant blazars are indeed attenuated more than gamma rays from nearby blazars, a result announced on November 30, 2012, in a paper published in Science, as theoretically predicted.

The attached figure illustrates how energetic gamma rays (dashed lines) from a distant blazar strike photons of extragalactic background light (wavy lines) and produce pairs of electrons and positrons.

From these measurements, Dominguez et al. were able to calculate the blazars» original emitted, unattenuated gamma - ray brightnesses at different energies.

So, astrophysicists developed an ingenious work - around method: measuring the EBL indirectly through measuring the attenuation of — that is, the absorption of — very high energy gamma rays from distant blazars.

When a high - energy gamma ray from a blazar strikes air molecules in the upper regions of Earth's atmosphere, it produces a cascade of charged subatomic particles.