Post by plutronus on Aug 16, 2014 13:42:09 GMT -6
Search for Gravity Waves and Dark Energy
From: ow.ly/2KgBAu (Xilinx)
By: sleibso
07-16-2014 - 11:14 AM
(735 Views)
A multidisciplinary team of scientists at
the South Pole recently stared into the afterglow of the Big Bang. The
team announced on March 17, 2014 that the BICEP2 experiment had collected the
first evidence of gravity waves in the B-mode polarization of the cosmic
microwave background (CMB).
Now scientists are looking for yet another fingerprint: evidence of
gravity waves as recorded in the faint polarization spirals of CMB
microwave photons. Finding these spirals would seem to confirm the
inflation aspect of Big Bang theory—the idea that the universe expanded
much faster than the speed of light long before the universe was even a
picosecond old. In theory, this superluminal (faster than light speed)
cosmic inflation created gravity waves that were embossed into the
polarization of photons from the Big Bang.
The special camera the team is relying on to search for gravity waves
uses transition-edge sensor (TES) bolometers to measure both E-mode
(curl-free) and B-mode (gradient-free) microwave radiation. The camera
is built around a second-generation McGill University DFMUX board based
on Xilinx Virtex-4 FPGAs.
Astrophysicists elsewhere are using the same Xilinx board in their
own experiments, while other researchers are trying out a new version of
the camera updated with Kintex-7 devices. The Kintex version is also
part of a mammoth telescope that Canadian scientists will use to
investigate dark energy.
ECHOES OF THE BIG BANG
The polarization variation in the CMB microwave photons is called the
B-mode signal and the signature is extremely faint. While the overall
CMB black-body temperature is 2.73 Kelvin, the B-mode signal is roughly
one 10 millionth of a Kelvin.
The B-mode signal is generated at small angular scales by the
gravitational lensing of the much larger, primordial “E-mode”
polarization signal, and at large angular scales by the interaction of
the CMB with a background of gravitational waves produced during the Big
Bang’s inflationary period.
B-mode polarization caused by gravitational lensing of the CMB was
first detected in 2013 by the SPT polarimeter (SPTpol) camera installed
on the 10-meter South Pole Telescope (SPT), which is operated by an
international scientific team (Figure 1). The SPT is co-located at the
Amundsen-Scott South Pole Station with the BICEP2 (soon to be BICEP3)
and Keck Array CMB experiments.
CMB radiation is the last echo of the immense energy burst that
accompanied the Big Bang. Arno Penzias and Robert Wilson accidentally
discovered it in 1964 as they experimented with cryogenic receivers to
investigate sources of radio noise for Bell Telephone Laboratories in
Holmdel, NJ. The CMB was the one noise source that the two scientists
could not eliminate from their experimental data. Discovery of CMB
radiation confirmed the cosmological Big Bang theory and earned Penzias
and Wilson the Nobel Prize in Physics in 1978.
Based on the resolving power of that early-1960s experimental
apparatus, the CMB appeared to be uniform in every direction and at all
times of the day and night. That characteristic supported the theory
that the CMB was a remnant of the Big Bang. More sensitive measurements,
notably those performed by the Cosmic Background Explorer satellite,
mapped the entire sky’s worth of CMB to a very high resolution and
showed that there were minute variations (anisotropy) in the CMB, which
further reinforced the theory that the CMB was a fingerprint of the Big
Bang. This discovery earned George Smoot and John Mather the Nobel Prize
in Physics in 2006.
To read the remainder of the article, please visit: ow.ly/2KgBAu
From: ow.ly/2KgBAu (Xilinx)
By: sleibso
07-16-2014 - 11:14 AM
(735 Views)
A multidisciplinary team of scientists at
the South Pole recently stared into the afterglow of the Big Bang. The
team announced on March 17, 2014 that the BICEP2 experiment had collected the
first evidence of gravity waves in the B-mode polarization of the cosmic
microwave background (CMB).
Now scientists are looking for yet another fingerprint: evidence of
gravity waves as recorded in the faint polarization spirals of CMB
microwave photons. Finding these spirals would seem to confirm the
inflation aspect of Big Bang theory—the idea that the universe expanded
much faster than the speed of light long before the universe was even a
picosecond old. In theory, this superluminal (faster than light speed)
cosmic inflation created gravity waves that were embossed into the
polarization of photons from the Big Bang.
The special camera the team is relying on to search for gravity waves
uses transition-edge sensor (TES) bolometers to measure both E-mode
(curl-free) and B-mode (gradient-free) microwave radiation. The camera
is built around a second-generation McGill University DFMUX board based
on Xilinx Virtex-4 FPGAs.
Astrophysicists elsewhere are using the same Xilinx board in their
own experiments, while other researchers are trying out a new version of
the camera updated with Kintex-7 devices. The Kintex version is also
part of a mammoth telescope that Canadian scientists will use to
investigate dark energy.
ECHOES OF THE BIG BANG
The polarization variation in the CMB microwave photons is called the
B-mode signal and the signature is extremely faint. While the overall
CMB black-body temperature is 2.73 Kelvin, the B-mode signal is roughly
one 10 millionth of a Kelvin.
The B-mode signal is generated at small angular scales by the
gravitational lensing of the much larger, primordial “E-mode”
polarization signal, and at large angular scales by the interaction of
the CMB with a background of gravitational waves produced during the Big
Bang’s inflationary period.
B-mode polarization caused by gravitational lensing of the CMB was
first detected in 2013 by the SPT polarimeter (SPTpol) camera installed
on the 10-meter South Pole Telescope (SPT), which is operated by an
international scientific team (Figure 1). The SPT is co-located at the
Amundsen-Scott South Pole Station with the BICEP2 (soon to be BICEP3)
and Keck Array CMB experiments.
CMB radiation is the last echo of the immense energy burst that
accompanied the Big Bang. Arno Penzias and Robert Wilson accidentally
discovered it in 1964 as they experimented with cryogenic receivers to
investigate sources of radio noise for Bell Telephone Laboratories in
Holmdel, NJ. The CMB was the one noise source that the two scientists
could not eliminate from their experimental data. Discovery of CMB
radiation confirmed the cosmological Big Bang theory and earned Penzias
and Wilson the Nobel Prize in Physics in 1978.
Based on the resolving power of that early-1960s experimental
apparatus, the CMB appeared to be uniform in every direction and at all
times of the day and night. That characteristic supported the theory
that the CMB was a remnant of the Big Bang. More sensitive measurements,
notably those performed by the Cosmic Background Explorer satellite,
mapped the entire sky’s worth of CMB to a very high resolution and
showed that there were minute variations (anisotropy) in the CMB, which
further reinforced the theory that the CMB was a fingerprint of the Big
Bang. This discovery earned George Smoot and John Mather the Nobel Prize
in Physics in 2006.
To read the remainder of the article, please visit: ow.ly/2KgBAu