Hola amigos: A VUELO DE UN QUINDE EL BLOG., la Agencia Espacial NASA nos trae la información de :....."púlsar raro y poderoso (rosa) se puede ver en el centro de la Galaxia Messier 82 en este nuevo retrato multi-longitud de onda. - un tipo de estrella muerta - utilizando es de alta energía de rayos X visión, el descubrimiento fue hecho por NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR.
"Se podría pensar de este púlsar como el 'Super Ratón' de remanentes estelares", dijo Fiona Harrison, el investigador principal de NuSTAR en el Instituto de Tecnología de California en Pasadena, California. "Tiene todo el poder de un agujero negro, pero con mucha menos masa."
A rare and mighty pulsar (pink) can be seen at the
center of the galaxy Messier 82 in this new multi-wavelength portrait. NASA's
NuSTAR mission discovered the "pulse" of the pulsar — a type of dead star —
using is high-energy X-ray vision.
Image Credit:
NASA/JPL-Caltech
feature Link:
This animation shows a neutron star -- the core of
a star that exploded in a massive supernova. This particular neutron star is
known as a pulsar because it sends out rotating beams of X-rays that sweep past
Earth like lighthouse beacons.
Image Credit:
NASA/JPL-Caltech
Feature Link:
The brightest pulsar detected to date is shown in
this animation that flips back and forth between images captured by NASA's
Nuclear Spectroscopic Telescope Array, or NuSTAR.
Image Credit:
NASA/JPL-Caltech
Feature Link:
This image shows the core of galaxy Messier 82
(M82), where two ultraluminous X-ray sources, or ULXs, reside (X-1 and X-2).
ULXs are regions that shine intensely with X-rays.
Image Credit:
NASA/JPL-Caltech/SAO
Feature Link:
This chart illustrates the relative masses of
super-dense cosmic objects, ranging from white dwarfs to the supermassive black
holes encased in the cores of most galaxies.
Image Credit:
NASA/JPL-Caltech
Feature Link:
The galaxy Messier 82 (M82) is seen here in two
different lights. A visible-light view from NASA's Hubble Space Telescope is at
left, and an X-ray view from NASA's Chandra X-ray Observatory is at
right.
Image Credit:
NASA/STScI/SAO
Feature Link:
Astronomers have found a pulsating, dead star beaming with the energy of
about 10 million suns. This is the brightest pulsar – a dense stellar remnant
left over from a supernova explosion – ever recorded. The discovery was made
with NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR.
"You might think of this pulsar as the 'Mighty Mouse' of stellar remnants,"
said Fiona Harrison, the NuSTAR principal investigator at the California
Institute of Technology in Pasadena, California. "It has all the power of a
black hole, but with much less mass."
The discovery appears in a new report in the Thursday Oct. 9 issue of the
journal Nature.
The surprising find is helping astronomers better understand mysterious
sources of blinding X-rays, called ultraluminous X-ray sources (ULXs). Until
now, all ULXs were thought to be black holes. The new data from NuSTAR show at
least one ULX, about 12 million light-years away in the galaxy Messier 82 (M82),
is actually a pulsar.
"The pulsar appears to be eating the equivalent of a black hole diet," said
Harrison. "This result will help us understand how black holes gorge and grow so
quickly, which is an important event in the formation of galaxies and structures
in the universe."
ULXs are generally thought to be black holes feeding off companion stars -- a
process called accretion. They also are suspected to be the long-sought after
"medium-size" black holes – missing links between smaller, stellar-size black
holes and the gargantuan ones that dominate the hearts of most galaxies. But
research into the true nature of ULXs continues toward more definitive
answers.
NuSTAR did not initially set out to study the two ULXs in M82. Astronomers
had been observing a recent supernova in the galaxy when they serendipitously
noticed pulses of bright X-rays coming from the ULX known as M82 X-2. Black
holes do not pulse, but pulsars do.
Pulsars belong to a class of stars called neutron stars. Like black holes,
neutron stars are the burnt-out cores of exploded stars, but puny in mass by
comparison. Pulsars send out beams of radiation ranging from radio waves to
ultra-high-energy gamma rays. As the star spins, these beams intercept Earth
like lighthouse beacons, producing a pulsed signal.
"We took it for granted that the powerful ULXs must be massive black holes,"
said lead study author Matteo Bachetti, of the University of Toulouse in France.
"When we first saw the pulsations in the data, we thought they must be from
another source."
NASA's Chandra X-ray Observatory and Swift satellite also have monitored M82
to study the same supernova, and confirmed the intense X-rays of M82 X-2 were
coming from a pulsar.
"Having a diverse array of telescopes in space means that they can help each
other out," said Paul Hertz, director of NASA's astrophysics division in
Washington. "When one telescope makes a discovery, others with complementary
capabilities can be called in to investigate it at different wavelengths."
The key to NuSTAR's discovery was its sensitivity to high-energy X-rays, as
well as its ability to precisely measure the timing of the signals, which
allowed astronomers to measure a pulse rate of 1.37 seconds. They also measured
its energy output at the equivalent of 10 million suns, or 10 times more than
that observed from other X-ray pulsars. This is a big punch for something about
the mass of our sun and the size of Pasadena.
How is this puny, dead star radiating so fiercely? Astronomers are not sure,
but they say it is likely due to a lavish feast of the cosmic kind. As is the
case with black holes, the gravity of a neutron star can pull matter off
companion stars. As the matter is dragged onto the neutron star, it heats up and
glows with X-rays. If the pulsar is indeed feeding off surrounding matter, it is
doing so at such an extreme rate to have theorists scratching their heads.
Astronomers are planning follow-up observations with NASA's NuSTAR, Swift and
Chandra spacecraft to find an explanation for the pulsar’s bizarre behavior. The
NuSTAR team also will look at more ULXs, meaning they could turn up more
pulsars. At this point, it is not clear whether M82 X-2 is an oddball or if more
ULXs beat with the pulse of dead stars. NuSTAR, a relatively small telescope,
has thrown a big loop into the mystery of black holes.
“In the news recently, we have seen that another source of unusually bright
X-rays in the M82 galaxy seems to be a medium-sized black hole," said astronomer
Jeanette Gladstone of the University of Alberta, Canada, who is not affiliated
with the study. "Now, we find that the second source of bright X-rays in M82
isn’t a black hole at all. This is going to challenge theorists and pave the way
for a new understanding of the diversity of these fascinating objects."
More information about NuSTAR is online at:
NASA
Guillermo Gonzalo Sánchez Achutegui
No hay comentarios:
Publicar un comentario