... an X-ray telescope which will be lifted to an
altitude of ~40 km with an enormous helium-filled
(one million cubic metres) in July 2012. Through
ability to determine the polarisation of X-rays, we aim
a new observational window on the Universe.
The next launch window for PoGOLite opens in summer
Follow our progress here:
/ OKC Blog
SNSB / SSC
Balloon trajectory (will be activated close to the
at KTH (Swedish)
in Forskning och Framsteg (Swedish)
PoGOLite: a brief introduction
|Shortly after midsummer, an
enormous helium-filled balloon will be launched from the
Esrange Space Centre near Kiruna with the PoGOLite
(Polarised Gamma-ray Observer) telescope dangling under it.
The PoGOLite telescope will study the high energy light
(known as X-rays) emitted by heavenly bodies such as neutron
stars, pulsars and black hole systems. When fully inflated,
the balloon has a volume of about 1 million cubic metres
which is twice the volume of the Globen Arena in Stockholm.
The balloon has to be so large because PoGOLite is not so
light - it weighs about 2 Tonnes. It is important to lift
PoGOLite as high as possible since X-rays are absorbed by
the Earth's atmosphere.
After launch, PoGOLite will drift Westwards on stratospheric
winds passing over Sweden, Norway, Iceland, Greenland and
Canada. We are hoping to be able to continue the flight over
Alaska and onwards over Russia, returning to Sweden some 20
X-ray emission from the Crab pulsar (artist's
How polarised sunglasses help remove
glare reflected from water.
|One of the observation
targets for PoGOLite are neutron stars. A neutron star is
formed when a star of a certain size has expended all its
fuel and collapses in on itself releasing huge amounts of
energy in a so-called supernova explosion. The conditions
during the collapse are so extreme that the atoms in the
star are pressed together converting protons and electrons
into neutrons. A neutron star is very small, only 15 km in
diameter, but weighs an astonishing one and a half times as
much as the Sun. A teaspoon of neutron star material would
weigh a billion tonnes!
A neutron star which rotates is called a pulsar. A pulsar in
the constellation of Taurus called ‘The Crab’ rotates 30
times a second and sends out flashes of X-rays, like a
cosmic lighthouse. The supernova explosion which gave rise
to the Crab was recorded by Chinese and Arab astronomers in
year 1054. We plan to intercept Crab X-rays with PoGOLite
and measure their polarisation in order to learn more about
how X-rays are produced in the pulsar.
X-rays are a form of electromagnetic radiation, just like
visible light or radio waves. The polarisation of a wave
describes how the oscillation of the wave is oriented with
respect to the wave’s motion. Now that it’s summer, check
your sunglasses - they may be polarised. If you’re near
water on a sunny day you’ll notice a glare on the water as
sunlight is reflected towards your eyes. You can remove much
of this glare by putting on your polarised sunglasses. This
is because the reflected light waves become polarised as
they ‘bounce off’ the surface of the water and your
sunglasses are designed to block these polarised waves. In a
similar fashion X-rays can become polarised as they leave a
For technical details, please refer to the publications and
(c) Posten Frimärken. Designer: Einar
PoGOLite was featured on two stamps issued by the Swedish post
office in January 2009 to mark the International Year of
Astronomy. A number of first-day covers featuring the stamps will
be flown on-board the maiden flight.
PoGOLite is a Swedish-lead
project headed by the Particle
and Astroparticle Physics group within the Physics
Department of The Royal Institute of Technology (KTH). We are one of the founding
members of The Oskar Klein
Centre for Cosmoparticle Physics at AlbaNova University
Centre in Stockholm. At AlbaNova,
we also work with members of the infra-red astronomy group at Stockholm University.
Internationally, we collaborate with USA (SLAC/KiPAC, University
of Hawaii) and a Japanese consortium (Hiroshima University,
ISAS/JAXA, Waseda University, Tokyo Institute of Technology). The
PoGOLite attitude control system was developed in conjunction with
DST Control in Linköping and SSC
Esrange developed the PoGOLite gondola, power and
communication systems and provide support during the campaign
phase of the project. An auroral monitor developed by the KTH Alfvén Laboratory is
included in the pathfinder flight.
Swedish participation in
PoGOLite was made possible through a grant awarded in 2005 by The
Knut and Alice Wallenberg
Now-a-days, PoGOLite is classified as a National Project by the Swedish
National Space Board
and as such enjoys programmatic support, including support from
SSC Esrange. The Swedish Research Council (Committee for research
infrastructure) has funded our work on the attitude control
system. Several PoGOLite team members receive salary support
('friköp') from The Swedish Research Council or The Swedish
National Space Board. The Göran Gustafsson
Foundation has funded
work on the star tracker systems. Some support has been recevied
from KTH in the form of faculty
Selected publications and
- M. Pearce et al., "Balloon-borne hard X-ray polarimetry with
PoGOLite". Proceedings of IEEE Nuclear Science Symposium,
Anaheim, USA. [paper]
- M. Kiss, "Polariserad strålning på jorden och i rymden",
AlbaNova öppen föreläsning, 24 April 2012.
- M. Pearce, "PoGOLite - a balloon-borne X-ray polarimeter".
13th ICATPP conference on astroparticle, particle, space physics
and detectors for physics applications. Villa Olma, Como, Italy.
6th October 2011.
- M. Pearce, "Balloon-borne gamma-ray polarimetry". 20th ESA
Symposium on European Rocket and Balloon Programmes and Related
Research, Hyères, 22-26 May 2011. [paper]
- M. Jackson, "Control system, operating modes, and
communications for PoGOLite". 20th ESA Symposium on European
Rocket and Balloon Programmes and Related Research, Hyères,
22-26 May 2011. [paper]
- M. Kiss, "Measurements of astrophysical polarisation using
Compton scattering". Imaging 2010, Stockholm. June 8-11, 2010.
- M. Pearce, M. Jackson, et al., "PoGOLite - a high sensitivity
balloon-borne soft gamma-ray polarimeter". IEEE Nuclear Science
Symposium, Orlando, USA, 25-31 October 2009. [poster] [paper]
- M. Pearce. "PoGOLite - a high sensitivity balloon-borne soft
gamma-ray polarimeter". The coming age of X-ray polarimetry,
Rome, April 2009. [talk] [paper]
- M. Kiss. "Studies of neutron background rejection in the
PoGOLite balloon-borne polarimeter". The coming age of X-ray
polarimetry, Rome, April 2009.
- M. Jackson. "Pre-flight tests of the PoGOLite detector
system". The coming age of X-ray polarimetry, Rome, April 2009.
- M. Axelsson. "Observing polarised X-rays with PoGOLite". The
coming age of X-ray polarimetry, Rome, April 2009.
- T. Mizuno et al., "A Monte Carlo method for calculating the
energy response of plastic scintillators to polarized photons
below 100 keV". Nucl. Instr. and Meth. A 600 (2009) 609.
- M. Pearce, "PoGOLite - a high
sensitivity balloon-borne soft gamma-ray polarimeter".
IEEE Nuclear Science Symposium, Dresden, Germany. October 2008.
- C. Marini Bettolo. "The PoGOLite star tracker system". IEEE
Nuclear Science Symposium, Dresden, Germany. October 2008.
- W. Klamra. "Performance of BGO crystals for the PoGOLite
gamma-ray polarimeter". IEEE Nuclear Science Symposium, Dresden,
Germany. October 2008.
- T. Kamae et al., "PoGOLite
A High Sensitivity Balloon-borne Soft Gamma-ray Polarimeter".
Astroparticle Physics 30 (2008) 72. arXiv:0709.1278v2
- M. Kiss, "The PoGOLite balloon-borne soft gamma-ray
polarimeter. Proc. Cool discs, hot flows: The varying faces of
accreting compact objects, Funäsdalen, Sweden, March 2008. AIP
studera röntgenstrålning på ett nytt sätt,
ESA news item, 6th September 2007.
- M. Kiss, ‘The PoGOLite balloon-borne soft gamma-ray
polarimeter’. Proc. International Conference on Advanced
Technology and Particle Physics (ICATPP), Como, Italy, October
2007. World Scientific.
- M. Pearce et al., "PoGOLite: a
balloon-borne soft gamma-ray polarimeter". Proceedings of
30th International Cosmic Ray Conference, Mérida, Mexico. June
- C. Marini Bettolo et al., "The
anticoincidence system of the PoGOLite balloon-borne soft
gamma-ray polarimeter". Proceedings of 30th
International Cosmic Ray Conference, Mérida, Mexico. June 2007.
- S. Larsson et al., "Studies of
Auroral X-ray Backgrounds for high latitude balloon
astrophysics experiments". Proc. Proc. 18th ESA Symposium
on European Rocket and Balloon Programmes and Related Research.
Visby, Sweden. 3-7 June 2007. [talk]
- T. Mizuno et al., "High
Sensitivity Balloon-Borne Hard X-Ray/Soft Gamma-Ray
Polarimeter PoGOLite". Submitted (summary) to IEEE Nuclear
Science Symposium, Honolulu, Hawaii. October 2007.
- T. Tanaka et al., "Data
Acquisition System for the PoGOLite astronomical hard X-ray
polarimeter". Submitted (summary) to IEEE Nuclear Science
Symposium, Honolulu, Hawaii. October 2007.
- M. Axelsson et al., "Measuring energy dependent polarisation
in soft gamma-rays using Compton scattering in PoGOLite". astro-ph/07041603.
Astroparticle Physics 28 (2007) 327. [newsflash]
- M. Kiss and M. Pearce, "PoGOLite:
a new window on the Universe with polarised gamma-rays".
Proceedings of 'Imaging 2006', Stockholm, June 2006. Nucl.
Instr. and Meth. A.
- F. Ryde, Stefan Larsson, Nickolay Ivchenko, and Mark Pearce, "Auroral X-ray emission".
November 2006. Internal note.
- Y. Kanai et al., "Beam test of a prototype
phoswich detector assembly for the PoGOLite astronomical soft
gamma-ray polarimeter". Nucl. Instr. and Meth. A570 (2007)
- J. Kataoka et al., ‘Low energy response
of a prototype detector array for the PoGO Astronomical Hard
X-ray Polarimeter’. Proc. Photonics for Space Environments
X. SPIE, Volume 5898 (2005).
- V. Andersson et al., "Large area
balloon-borne polarised gamma-ray observer (PoGO)".
Proceedings of the 22nd Symposium on Relativistic Astrophysics
at Stanford University, December 2004.
- Stefan Larsson and Mark Pearce, "PoGO: The
polarised gamma-ray observer". Nucl. Instr. and Meth. A
525 (2004) 148. Proceedings of 'Imaging 2003', Stockholm, June
2003. Nucl. Instr. and Meth. A.
- Anders Jonsson, KTH, 'Laboratory tests
and reassembly of the PoGOLite detector array' (2012)
- Nick Barkas, KTH, 'Computer
simulations for the PoGOLite pathfinder experiment' (2010)
- Pau Mallol, KTH, 'A cooling system for
PoGOLite - a balloon-borne soft gamma-ray polarimeter'
- Kristoffer Myrsten, KTH, 'PoGOLite
pathfinder experiment: neutron shield design and limits on
polarisation measurements' (2008).
- Jaroslav Kazejev, KTH, 'Neutron
background studies for PoGOLite' (2007).
- Tomas Ekeberg, KTH, 'Polarimetry
measurements with the PoGOLite prototype and simulations of
polarisation in inverse Compton scattering processes'
- Bianca Iwan, KTH, 'Development of the
PoGOLite Star Tracker System and construction of detector
units for the Polarimeter Telescope Assembly' (2007).
- Olle Engdegård, KTH/SU, 'Studies
of energy dependent polarisation with PoGOLite' (2006).
- Mózsi Kiss, KTH, 'Construction
laboratory tests of the PoGOLite prototype' (2006).
- Tomi Ylinen, KTH, 'Constrcution
and accelerator-based tests of the PoGOLite prototype'
- Viktor Andersson, KTH, 'Tests
of scintillators and PMTs for the Polarised Gamma-ray Observer
- Markus Suhonen, KTH, 'Tests of PoGO