5.4� A&G�•�October�2011�•�Vol.�52

Who, what, where?

Sue Bowler, EditorThere�are�a�lot�of�forms�to�fill�in�these�days�–�so�many�in�fact�that�it�is�easy�to�dismiss�

them�all�as�tedious�box-ticking�exercises.�But�some�of�them�are�really�useful.�The�information-gathering�for�the�RAS�Survey�of�Demographic�Trends�is�among�the�useful�ones,�providing�as�it�does�a�snapshot�of�UK�research�astronomy�at�intervals�over�the�past�decade�or�so.�This�year�there�has�also�been�a�focus�on�gaining�information�about�research�in�geophysics,�and�multidisciplinary�research�under�the�RAS�umbrella,�reflecting�increasing�appreciation�of�the�value�of�this�sort�of�benchmark�survey.�That�value�comes�in�two�forms:�appreciation�of�the�relative�sizes�of�our�research�communities�now,�and�the�changes�that�come�over�the�years.�

There�are�causes�for�congratulation�and�causes�for�concern.�A�third�of�our�postgraduate�research�students�are�female,�for�example,�which�suggests�that�the�RAS�sciences�are�disproportionately�good�at�attracting�women,�given�that�just�20%�of�A-level�physics�students�are�female.�However,�we�are�less�good�at�keeping�women:�a�dramatic�increase�in�professorial�staff�since�1998�has�not�been�matched�by�an�increase�in�women�at�that�level.�All�the�fields�covered�have�a�lot�of�professors;�they�form�up�to�56%�of�academic�staff,�against�39%�for�physics�as�whole�and�16%�for�all�university�research�areas.�

The�loss�of�potential�talent�is�much�worse�in�terms�of�the�diversity�of�backgrounds.�We�are�not�recruiting�the�most�talented�people�if�we�are�not�recruiting�from�all�communities.�The�black�and�minority�ethnic�profile�of�our�sciences�is�very�different�from�that�of�our�country�and�we�need�to�consider�ways�to�address�this�and�keep�finding�and�supporting�the�very�best�astronomers�and�geophysicists.

Editorial

NEws

LightSquared: a continuing threat to GNSS?Over the past few months, writes Peter Clarke, the part of the Glo-bal Navigation Satellite Systems community that uses the US Glo-bal Positioning System, has been in uproar over proposals to use for terrestrial mobile broadband a part of the L-band radio spectrum adjacent to that used by GPS. In November 2010, US wireless broadband wholesaler LightSquared Subsidiary LLC, which has rights over the 1525–1559 MHz part of the Mobile Satellite Services microwave band, sought approval from the US Federal Communications Commis-sion (FCC) for a modification of the Ancillary Terrestrial Component (ATC) of its proposed satellite broad-band system. After a short consul-tation period, conditional approval was granted in January 2011.

This seemingly innocuous change could in fact have removed the last safeguard against the terrestrial jam-ming of GPS signals. The principal L1 channel of GPS, shared with other GNSS such as the forthcoming Euro-pean Galileo in the 1559–1610 MHz band, is transmitted at very low power by satellites at 19 200 km alti-tude; the received power at Earth’s surface can be detected only using spread-spectrum techniques. Previ-ous modifications to the FCC licence to LightSquared and its predecessor SkyTerra had allowed more and more powerful ATC terrestrial base sta-tions, but kept the system principally satellite-based, ensuring that high-power ground transmissions were unlikely to affect GPS. This applica-tion seeks the removal of this limit, raising the real possibility of 40 000 base stations across the USA, each transmitting up to 15 kW of power.

As part of its conditional approval, the FCC ordered two independent testing groups, with LightSquared’s involvement, to investigate possi-ble interference covering two levels of use. Navigational GPS receivers normally achieve 1–10 m accuracy using binary spreading codes modu-lated onto the GPS carrier wave and are used for most military, civilian and emergency services. Geodetic (survey-grade) receivers track these binary codes and the underlying car-rier wave phase to achieve accuracy of 1–100 mm. They are typically used by geophysicists at ground-based observatories to study plate tectonics and at ground-based observatories or on low Earth-orbiting satellites to study atmospheric properties.

Results showed that most navi-gational receivers experienced sig-nificant interference at distances of 0.3–3 km from a LightSquared transmitter; geodetic receivers, at distances of 1–2 km. Projected trans-mitter spacings in the USA vary from 0.4 km in dense urban areas up to 8 km in rural areas. Airborne navi-gational receivers and spaceborne occultation receivers experienced interference out to 20–25 km and 300 km respectively.

In June, shortly before the publi-cation of the results, LightSquared suggested that it would consider delaying relevant operations, which would reduce (but not eliminate) the likelihood of interference for navi-gational GPS receivers. It would also allow more time for all GPS users to adapt or upgrade hardware. How-ever, this delay would be unlikely to benefit high-precision users of GPS:their higher-bandwidth carrier phase receivers would still be affected by

the initial LightSquared transmis-sions. Interference mitigation for such receivers is a much greater chal-lenge than for navigational GPS.

A period of FCC consultation (until July) followed publication of the results. The Directorate-General for Enterprise and Industry of the European Commission submitted a statement, raising concerns that the LightSquared system would impact receivers using Galileo, including distress beacons, that might be used in the USA. Such general receiver concerns also apply to scientific and industry users of other networks such as GLONASS wishing to use instru-ments in the USA. The US Depart-ments of Transport and Defense issued a joint letter expressing strong concern at the proposals. The Save our GPS coalition, formed in Febru-ary, and many others contributed to the consultation.

The FCC has already asked the GPS industry and LightSquared for further information. Motions passed in the US House of Representatives in May and June prevent the FCC from authorizing LightSquared to proceed until the concerns are answered. However, GPS World magazine reports that LightSquared has filed documents with the International Telecommunications Union in what may be an attempt to circumvent the FCC. The European Commission’s concern may yet seem prescient.Peter Clarke, Newcastle University; peter.clarke@newcastle.ac.ukhttp://www.saveourgps.orghttp://www.pnt.gov/interference/ lightsquaredhttp://www.insidegnss.comhttp://www.gpsworld.comhttp://www.lightsquared.com

It may look like the lifts that load the in-flight meals on to an airline, but this machine is in fact a big step towards efficient operations at ALMA, the Atacama Large Millimetre Array in Chile. This first Front End Service Vehicle will service the superconducting receivers within the ALMA telescopes without dismantling the telescopes and taking them out of operation for as much as four days; FESV 1 can do the job within an eight-hour shift. Previously the whole telescope was transported 60 km from an altitude of 5000 m to the support facility at around 3000 m. FESV 1 is insulated and equipped with everything needed to service the receivers in the harsh environment of the Atacama desert: a cryogenic compartment to keep the receivers at 4 K, telescope power supplies, air tanks, and a suite of maintenance equipment. The most specialized of these devices is a sturdy forklift trolley that can safely move an entire three-quarter ton ALMA receiver cabinet. (Carlos Padilla, NRAO/AUI/NSF)

New service vehicle boosts ALMA productivity

A&G�•�October�2011�•�Vol.�52�� 5.5

NEws

Superbubble in the Large Magellanic CloudSuperbubble LHA 120-N 44 in NGC1929, part of the Large Magellanic Cloud, is formed by the stellar winds from hot young stars – blue/white in this image – shaping the clouds of gas and dust, in this image from the European Southern Observatory. Shockwaves from supernova explosions add to the effect, and the intense ultraviolet radiation from the stars makes the gas and dust glow. As the gas and dust is compressed, new stars form in turn. This close-up image was made from ESO Very Large Telescope FORS-1 images identified by Manu Mejias, from Argentina, in ESO’s 2010 Hidden Treasures competition, in which people were invited to find impressive images in ESO archives. (ESO/Manu Mejias)

2012 Kavli Prize Nominations�for�the�2012�Kavli�Prize�in�astrophysics,�which�recognizes�scientists�whose�discoveries�have�dramatically�expanded�human�understanding,�are�open�until�1�December�2011.�The�prize�consists�of�a�scroll,�a�medal�and�$1m.�Nominations�may�be�submitted�electronically�at�the�Kavli�Prize�website.�The�Kavli�Prizes�are�a�partnership�between�The�Norwegian�Academy�of�Science�and�Letters,�The�Kavli�Foundation,�and�The�Norwegian�Ministry�of�Education�and�Research.�http://www.kavliprize.no

Astrophysics fellowship NASA�has�announced�a�new�fellowship�named�after�an�iconic�woman�astrophysicist.�The�Nancy�Grace�Roman�Technology�Fellowship�in�Astrophysics�is�designed�to�foster�technologies�that�advance�scientific�investigations�in�the�origin�and�physics�of�the�universe�and�future�exoplanet�exploration.�The�fellowship�will�help�early-career�researchers�develop�innovative�technologies�to�enable�scientific�breakthroughs,�while�creating�the�skills�necessary�to�lead�astrophysics�projects�and�future�investigations.�It�also�will�foster�and�support�early-career�instrument�builders�on�the�path�to�long-term�positions.�Roman’s�celebrated�career�included�multiple�scientific�and�technical�achievements�at�NASA�and�important�contributions�to�the�design�of�the�Hubble�Space�Telescope.�http://tinyurl.com/roman-fellowship

Prize for Overbye Science�writer�Dennis�Overbye�has�been�awarded�the�2011�David�N�Schramm�award�from�the�High�Energy�Astrophysics�Division�of�the�American�Astronomical�Society.�The�award�aims�to�recognize�and�stimulate�distinguished�writing.�Overbye�has�written�extensively�on�astrophysics,�including�the�books�Lonely Hearts of the Cosmos�and�Einstein in Love.�He�won�the�Schramm�award�for�an�examination�of�an�important�aspect�of�current�science,�the�political�and�financial�journey�required�to�develop�the�Alpha�Magnetic�Spectrometer.�http://www.nytimes.com/2010/11/17/science/space/17dark.html?ref= dennisoverbye

NEws iN BriEf

Model Milky Way – at lastIt has proved difficult to make a galaxy that looks anything like our Milky Way in cosmological simula-tion. Now a cold dark matter model known as Eris has produced a spi-ral galaxy that looks right, thanks to better star formation models. Eris owes its success to using lots of supercomputer time (principally on NASA’s Pleiades machine) on a simulation of just one galaxy. The detail allowed the small high-density clouds of gas where stars form to be resolved, and this is what resulted in a realistic galaxy. Previous simula-tions used the same cold dark matter model, but produced galaxies with a disproportionately large central bulge. Modelling the gas clouds means that the simulation includes gas loss because of supernovae, stop-ping large bulges from forming.http://news.ucsc.edu/2011/08/eris- simulation.html

Video-game technology, 2D and 3D images are helping NASA show off its science to the widest possible audience. Eyes on the Solar Sys-tem is a new web interface that allows users to ride along with NASA spacecraft and explore the solar system. The virtual environment uses the Unity game engine to display mod-els of planets, moons, asteroids, comets and spacecraft as they move through our solar system. With key-board and mouse controls, users cruise through space to explore anything that catches their interest. A free browser plug-in, available at the site, is required to run the Web application.

Time travel is also possible, with data running from 1950 and pro-jected until 2050, and you can speed it up or slow it down. For exam-ple, when NASA’s Juno spacecraft launched on 5 August this year, users could look ahead to see the mission’s

five-year journey to Jupiter in a mat-ter of seconds. NASA will add sci-ence mission data, for example from GRAIL and the Mars Science Labo-ratory, as it becomes available.

Users have a choice of points of view, ranging from faraway to on-board particular spacecraft. Loca-tion, motion and appearance are based on predicted and reconstructed mission data. Dozens of controls on a series of pop-up menus allow users to fully customize what they see, and video and audio tutorials explain how to use the tool’s many options. Users may choose from 2D or 3D modes, with the latter simply requir-ing a pair of red–cyan glasses.

This innovative means of exploring the solar system is at the beta release stage and comments are welcome. The interface and an introductory video can be downloaded from the website and updates on new features are avail-able via Twitter: @NASA_Eyes.http://solarsystem.nasa.gov/eyes

Gaming takes to the skies

5.6� A&G�•�October�2011�•�Vol.�52

NEws

Hubble jet movies reveal star formationAstronomers can now watch star formation as it happens, by watch-ing time-lapse movies made from 14 years of Hubble Space Tele-scope images of jets from young stars, phenomena that change over periods of a few years. The movies incorporate images that have been seen before as stills, but reveal patterns within the jets, including knots of gas brightening and dimming and collisions between fast-moving and slow-moving mat-erial, creating glowing arrowhead features.

Patrick Hartigan of Rice University in Houston, USA, and his colleagues used Hubble’s Wide Field Planetary Camera 2 to study several Herbig Haro objects – jets emanating from young stars as they condense. The jets are roughly 10 times the width of the solar system and travel at more than 700 000 km/hour.

The movies support previous observations which revealed that the twin jets ejected not in a steady stream, but sporadically, in clumps. The jets contain beads of more dense matter that might record epi-sodes when material fell onto the star. In the movies it is clear that the clumpy gas in the jets is moving at

different speeds; when fast-moving blobs collide with slower gas, bow shocks arise as the material heats up. In HH 2, for example, several bow shocks can be seen where several fast-moving clumps have bunched

up like cars in a traffic jam. In another jet, HH 34, a grouping

of merged bow shocks reveals regions that brighten and fade over time as the heated material cools where the shocks intersect. An analysis of the

movies is published by Hartigan et al. in The Astrophysical Journal. http://www.youtube.com/watch?v=0Yf_O-S4FM8http://sparky.rice.edu/~hartigan/movies.html

Giant jets of superfast particles are a feature of galaxies with supermassive black holes at their centres – but those galaxies are almost always elliptical. Now the second spiral galaxy to show such behaviour has been found, and it turns out to produce these large jets episodically, in a pattern found in one other elliptical galaxy only.The odd discovery made by an inter-national team of astronomers is a galaxy they have called Speca (Spiral-host Episodic radio galaxy tracing Cluster Accretion), that forms part of a galaxy cluster. The region is of interest because it represents an envi-ronment that was a lot more common when the universe was much younger, and so may reveal more about domi-nant processes then. The team used multiwavelength optical and radio survey data, as well as new obser-vations with the Giant Meterwave Radio Telescope in India, the Lulin Telescope in Taiwan and ultraviolet data from NASA’s GALEX satellite.

The picture that emerged was of a spiral galaxy with paired radio-emitting lobes emerging from the

poles, but lobes that formed three distinct pairs, presumably emitted sequentially in distinct episodes of activity. The oldest pair, furthest from the galaxy, were emitting at the lowest frequency. These lobes are old enough to have stopped emitting at radio frequencies, because the par-ticles would have lost most of their energy. But it appears that they have been “relighted” as a result of mat-erial falling into the cluster of galax-ies – a process that may have been more common in the early universe.

Details of this exotic galaxy are published in the Monthly Notices of the Royal Astronomical Society.http://www.nrao.edu/pr/2011/spiralradio

Astronomers discover second spiral galaxy with jets

RIght: Composite image of Speca showing the optical image of the galaxy from the Sloan Digital Sky Survey in yellow, the low-resolution radio image from National Radio Astronomy Observatory’s Very Large Array Sky Survey in blue, and the high-resolution radio image from the Giant Metrewave Radio Telescope in red. (Hota et al., SDSS, NCRA-TIFR, NRAO/AUI/NSF)

Clockwise from top: jets from Herbig Haro objects HH 47, HH 34 and HH 2. (NASA, ESA, P Hartigan [Rice University])

A&G�•�October�2011�•�Vol.�52�� 5.7

Diamond planetA�pulsar�survey�has�found�the�remnant�of�a�white�dwarf�that�appears�to�be�mostly�made�of�crystalline�carbon�–�a�diamond�planet.�An�unusual�modulation�in�the�signal�from�a�milli-second�pulsar,�J1719-1438,�was�attributed�to�a�companion�body,�found�to�be�half�the�size�of�Jupiter�(a�diameter�of�just�60�000�km)�with�density�greater�than�that�of�platinum.�Carbon�and�oxygen�must�predominate,�and�the�density�suggests�a�crystalline�state.�The�research�team�characterizes�it�as�more�of�a�planet�than�a�star,�and�infers�that�much�of�it�could�be�diamond.�There�are�movies�of�the�pulsar�system�available�at�the�Swinburne�University�of�Technology�astronomy�website.http://astronomy.swin.edu.au/ production/pulsarhttp://www.mpg.de/4406441/diamond_planet

Flares linger longer Solar�flares�continue�to�release�energy�for�up�to�five�hours�beyond�the�initial�minutes�of�an�event�and�the�extended�phase�of�the�flare�sometimes�carries�the�majority�of�the�energy�released.�The�data�come�from�the�Extreme�ultraviolet�Variability�Experiment�on�NASA’s�Solar�Dynamics�Observatory�and�include�a�flare�on�3�November�2010.�In�this�case,�the�energy�in�the�initial�solar�flare�represented�an�underestimate�of�the�total�energy�reaching�the�Earth’s�atmosphere�by�70%.�The�new�capability�will�provide�a�much�more�accurate�estimation�of�the�total�energy�input�into�Earth’s�environment.http://www.nasa.gov/sdo

Supernova successWidespread�publicity�surounded�the�announcement�that�a�nearby,�recently�discovered�and�still�brightening�supernova�was�visible�in�UK�skies.�This�was�a�useful�and�topical�opportunity�to�focus�public�enthusiasm�for�star-gazing�on�topics�relevant�to�current�research.�The�supernova�PTF11kly�lies�in�M101,�the�pinwheel�galaxy,�and�was�visible�with�binoculars�or�small�telescopes.�It�is�a�type�1a�supernova,�the�type�used�to�measure�cosmological�distances.�Despite�cloudy�late�summer�skies,�the�supernova�proved�an�appealing�prospect�to�the�public.http://www.spacecentre.co.uk

NEws iN BriEf

When a watch beats a compassFrom Prof. K A WhalerEven with the relatively large errors Jian and Baruch (A&G 52 3.12) estimate from using a watch to find south, the method does better than using a compass at many places

and times! Not surprisingly, the difference between true north and the direction a compass points in is largest towards the poles, but it is more than 20° even at some points on the equator (see e.g. Finlay et al. 2011 Geophys. J. Int. 183 1216 figure 1). The South Atlantic Anom-aly, where field strengths are much lower than would be predicted by

the best-fitting magnetic dipole at the Earth’s centre, is the main cause of the low-latitude discrepancy; field strengths here have been weakening for some time now and the area is increasingly suffering the consequences of space weather.Kathryn A Whaler, Professor of Geophysics, University of Edinburgh, UK. http://www.geos.ed.ac.uk/homes/whaler

ViEws

NEws • ViEws

The fifth largest dwarf planet, 2007 OR10, is half the size of Pluto and is an icy world with much surface water ice and probably the remnants of a methane atmo-sphere – making it an example of a dwarf planet just big enough to hold on to some volatiles, but other-wise like the smaller majority of objects in the Kuiper Belt. This dwarf planet was discovered in 2007 by Caltech graduate student

Meg Schwamb and thought of as another pale icy Kuiper Belt Object, although it was soon found to be red in colour. Now spectroscopic obser-vations using the Folded-port Infra-red Echellette (FIRE) on the 6.5 m Magellan Baade Telescope in Chile have shown that it has a surface of water ice.

Dwarf planet Quaoar also has a water ice surface with a reddish tinge, thought to be a result of radiation-

induced polymerization of methane at the surface. The methane is prob-ably a remnant of an atmosphere. But 2007 OR10 is smaller than Quaoar and methane has not been identified – although the red surface is evidence that it once was there. This dwarf planet seems to fit in between the larger KBO bodies with enough mass to hold a volatile atmosphere and the more usual, smaller icy bodies. This research is published by Brown et al. in Astrophysical Journal Letters. http://arxiv.org/abs/1108.1418

Orbiter takes closer look at the Moon

This image of the Apollo 17 landing site reveals the final footprints left on the Moon, as well as the buggy (Lunar Roving Vehicle, LRV) and the descent stage of the Challenger lunar module. Other images from NASA’s Lunar Reconnaissance Orbiter show descent stages of modules such as Antares, and the Surveyor 3 lander close to the Apollo 12 lander Intrepid. The LRO has taken advantage of a more elliptical orbit to obtain closer, sharper images of the traces left by Apollo astronauts on the Moon. It captured images of the Apollo spacecraft and rover tracks in 2009; now it has delivered images sharp enough to distinguish between lines of footprints and the double wheel tracks of the Moon buggy, showing exactly where astronauts walked, took samples and set up experiments. The LRO orbit was altered to make it a more extreme ellipse, without affecting the average altitude. The new orbit brought LRO to within 21 km of the surface at the nearest point on the sunlit side. The orbit was maintained for 28 days in order to get complete coverage of the surface, and on 6 September the orbiter returned to its normal orbit. (NASA/Goddard/ASU)http://www.nasa.gov/mission_pages/LRO/news/apollo-sites.html

Dwarf planet is an in-betweener