Mapping the Milky Way from Space
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Transcript of Mapping the Milky Way from Space
GEORGE SEABROKE
Mapping the Milky Way from space
MULLARD SPACE SCIENCE LABORATORY
Credits: ESA/ATG medialab;
background image: ESO/S. Brunier
MULLARD SPACE SCIENCE LABORATORY
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Milky Way (artist’s impression):How many stars?
Credit: NASA/JPL-Caltech/R. Hurt
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Milky Way (artist’s impression):100-200 billion stars
Credit: NASA/JPL-Caltech/R. Hurt
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Gaia will measure astrometry & photometry of ? stars & radial velocities of ? stars
Credit: NASA/JPL-Caltech/R. Hurt
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Gaia will measure astrometry & photometry of 1 billion stars & radial velocities of 75-100 million stars
Credit: NASA/JPL-Caltech/R. Hurt
Distribution of stars for
which radial velocities
will be precisely
(< 15 km/s) measured
(V < 15.2)
in a mock spiral galaxy
as seen by Gaia, as
predicted by
SNAPDRAGONS
(Hunt et al. 2015)
Log (star #)
MULLARD SPACE SCIENCE LABORATORY
Credit: Leanne Guy
One of the primary mirrors being mounted on Gaia
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Credit: Astrium SAS
Gaia’s 106 CCDs integrated onto its focal plane
Gaia’s 106 CCDs integrated onto its focal plane
Credit: Astrium
106 digital cameras, each with 8.8 Mega pixels 106 x 8,847,000 pixels = 937,782,000 pixels Nearly 1 billion pixels or 1000 Mega pixels!
0.5°
Gaia0.000000002°
0.000000002°
Spectroscopy
Redder colours:
longer wavelengths
Bluer colours:
shorter wavelengths
Electromagnetic spectrumVictor Blacus (http://en.wikipedia.org/wiki/File:Electromagnetic-Spectrum.svg)
Victor Blacus (http://en.wikipedia.org/wiki/File:Electromagnetic-Spectrum.svg)
Electromagnetic spectrum
Doppler effect with sound waves
Doppler effect with sound waves
Doppler effect with light waves
http://www.astronomynotes.com/light/s10.htm
What is a radial velocity?
What is a radial velocity?
Position
DDistance measured by parallax
What is a radial velocity?
Position
DDistance measured by parallax
What is a radial velocity?
Position
DDistance measured by parallax
Distanceconverts
proper motionsto
transverse velocity (Vt)
What is a radial velocity?
Position
Effect of parallax (the Earth’s orbital motion around the Sun, with a period of 1 year).
System’s barycentricmotion viewed from the Solar System barycentre.
Exo-Planets
System’s barycentricmotion viewed from the Solar System barycentre.
Effect of parallax (the Earth’s orbital motion around the Sun, with a period of 1 year).
Apparent motion of the star as a result of the planet, theadditional perturbation being magnified by ×30 for visibility.
DDistance measured by parallax
Distanceconverts
proper motionsto
transverse velocity (Vt)
Space velocity (any direction)
What is a radial velocity?
Position
DDistance measured by parallax
Distanceconverts
proper motionsto
transverse velocity (Vt)
Space velocity (any direction)
Radial velocity (Vr)
What is a radial velocity?
Position
http://www.projectrho.com/public_html/starmaps/media/4dmaps/spacevel.png
Modelling the Milky Way using supercomputersRob Grand, Jason Hunt (PhD students), Daisuke Kawata, MSSL
http://en.wikipedia.org/wiki/Oort_cloud
Gaia’s first science result: supernova!
Gaia’s first science result: supernova!
• hosts more than 10 billion photos
• hosts more than 10 billion photos• 1 petabytes (PB) = 1 million gigabytes (GB)
• hosts more than 10 billion photos• 1 petabytes (PB) = 1 million gigabytes (GB)
• Gaia’s final processed data storage = several PB
Summary
• Great recent years for the European Space Agency!
• 3 take home messages about Gaia:–Amazing (European) technology–Stars move!–You can get involved!