An image of the ring around the star Lambda Orionis, made with the ESA Planck satellite. The ring, here seen in pink, is around 200 light years across. In the image red represents the anomalous microwave emission (AME), green represents the emission from interstellar plasma and the blue is emission arising from electrons moving in magnetic fields. Credit: M. Peel / JCBA / Planck / ESA. Click here for a full size image
A ring of dust 200 light years across and a loop covering a third of the sky: two of the results in a new map from the Planck satellite. Dr Mike Peel and Dr Paddy Leahy of the Jodrell Bank Centre for Astrophysics (JCBA) presented the images today at the National Astronomy Meeting (NAM 2015) at Venue Cymru, Llandudno, Wales.
The European Space Agency (ESA) Planck satellite, launched in 2009 to study the ancient light of the Big Bang, has also given us maps of our own Galaxy, the Milky Way,
in microwaves (radiation at cm- to mm-wavelengths). Microwaves are
generated by electrons spiralling in the Galaxy's magnetic field at
nearly the speed of light (the synchrotron process); by collisions in interstellar plasma, by thermal vibration of interstellar dust grains, and by "anomalous" microwave emission (AME), which may be from spinning dust grains.
The relative strength of these processes changes with wavelength, and
are separated using multi-wavelength measurements from Planck, from
NASA's WMAP satellite, and from ground-based radio telescopes, giving maps of each component.
The new maps show regions covering huge areas of our sky that produce
AME; this process, only discovered in 1997, could account for a large
amount of galactic microwave emission with a wavelength near 1 cm. One
example where it is exceptionally bright is the 200 light year-wide dust
ring around the Lambda Orionis nebula (the 'head' of the familiar Orion constellation). This is the first time the ring has been seen in this way.
A
full sky map made using the ESA Planck satellite. Loop 1, marked by the
dashed ellipse, is the yellow feature above centre, shading to purple,
and the purple arc below centre. The colours represent the angle of the
magnetic field and the brightness represents the signal strength.
Credit: M. Peel / JCBA / Planck / ESA. Click here for a full size image
A wide field map also shows synchrotron loops and spurs (where charged
particles spiral around magnetic fields), including the huge Loop 1,
discovered more than 50 years ago. Remarkably, astronomers are still
very uncertain about its distance – it could be anywhere between 400 and
25,000 light years away – and though it covers around a third of the
sky it is impossible to say exactly how big it is.
Media contacts
Robert Massey
Royal Astronomical Society
Mob: +44 (0)794 124 8035
rm@ras.org.uk
Ms Anita Heward
Royal Astronomical Society
Mob: +44 (0)7756 034 243
anitaheward@btinternet.com
Dr Sam Lindsay
Royal Astronomical Society
Mob: +44 (0) 7957 566 861
sl@ras.org.uk
Science contacts
Dr Mike Peel
Jodrell Bank Centre for Astrophysics
michael.peel@manchester.ac.uk
Dr Paddy Leahy
Jodrell Bank Centre for Astrophysics
j.p.leahy@manchester.ac.uk
Prof Clive Dickinson
Jodrell Bank Centre for Astrophysics
clive.dickinson@manchester.ac.uk
Source: Royal Astronomical Society (RAS)
Further information
The new work has been submitted to “Planck 2015 results. XXV. Diffuse
low-frequency Galactic foregrounds”, the Planck Collaboration,
Astronomy and Astrophysics. See the preprint of this paper
Notes for editors
This research was supported by an ERC Starting (Consolidator) Grant (no. 307209) and STFC Consolidated Grant (no. ST/L000768/1).
Notes for editors
The Royal Astronomical Society National Astronomy Meeting
(NAM 2015) will take place in Llandudno, Wales, from 5-9 July. NAM 2015
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physics (MIST) groups. The conference is principally sponsored by the
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Jodrell Bank Centre for Astrophysics
(JBCA) is directly involved with the two lowest frequencies of the Low
Frequency Instrument, the 30 and 44 GHz radiometers. These have 4 and 6
detectors respectively, operating at 20K (-253.15°C or -423.67°F). The
resolution on the sky is 33 and 27 arc minutes, and the sensitivity 1.6
and 2.4 micro K (over 12 months). The cryogenic low noise amplifiers
which are the heart of the radiometers were developed at Jodrell Bank,
with help from the National Radio Astronomy Observatory in Virginia,
USA.
The work to understand the Galactic emission seen by Planck is being
co-led from Jodrell Bank by Emeritus Profs Rod Davies and Clive
Dickinson. A number of projects are led by Jodrell Bank scientists,
including Profs Richard Davis and Clive Dickinson. Each of the 14
projects focusses on one aspect of the Galaxy as seen by Planck,
including the electrons that gyrate in the Galactic magnetic field, the
ionized gas that pervades the interstellar medium and the dust grains
that emit across the entire frequency range that Planck is sensitive to.
Jodrell Bank is also leading the calibration and identifying
systematics in the LFI data.
