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- Photography as art in LJMU online feature
- SPRAT pipeline upgrade
- Liverpool Telescope at the forefront of the search for other Earths
- LT tracks rare microlensed quasar
Robert Smith's "Iridis" image of the Cat's Eye Nebula (featured in full here) has inspired an article on the Liverpool John Moores University (LJMU) main website about the more general concept of science as art, and art as science.
The image won the Robotic Scope Special Prize at the Insight Astronomy Photographer of the Year 2016. It was taken with the Liverpool Telescope's SPRAT spectrograph in slitless mode, so the light from the nebula was split into its constituent colours without first passing through a slit. As the nebula shines only in discrete colours, just a few individual images of the nebula can be seen, instead of a continuous spread from blue through to red.
Smith says: “We often hear about the idea of representing scientific data in an appealing way as an expression of art, but why not look at it the other way around; ‘art as science’? Astrophotography is not just a matter of making science look pretty, it shows us that beauty actually is science. The winners of this competition were obviously selected because they were beautiful, striking or interesting, but each and every one is also an expression of astrophysical processes and could be the basis of a science seminar in their own right. It is physics that creates that beauty. Looking at the swirling gas in a nebula or the aurorae, you are literally seeing maths and physics.”
All instruments on the Liverpool Telescope (LT) have automated data "pipelines" that process the raw data from the telescope into a finished form, i.e. science-ready data products, for the user to download the next working day. Not long ago the LT's SPectrograph for the Rapid Acquisition of Transients (SPRAT) got a major upgrade to its level 2 pipeline.
All data pass through a "Level 1" (L1) pipeline that removes low-level instrumental signatures such as bias, dark and flat-field effects. The SPRAT "Level 2" (L2) pipeline carried on from there to perform source extraction, sky subtraction and wavelength calibration, outputting 1D and 2D spectra as part of the process. All data products from the Level 2 SPRAT pipeline are stored as extra extensions in the SPRAT FITS files.
The upgrade to the L2 pipeline is that it now also performs flux calibration, stored as an extra FITS extension. This is a basic calibration that uses a template instrument response file, and generates its absolute calibration from the acquisition image. The precision is fine for the transient classification work that SPRAT is used for, and so will be very useful for the users performing that type of science.
Full details of the new SPRAT L2 pipeline can be found on the SPRAT webpage.
Liverpool Telescope helps to track down seven new planets
The Liverpool Telescope has helped to find seven Earth-sized worlds.
The discovery of a system of seven Earth-sized planets just 40 light-years away was made possible by a team of astronomers from across the world.
The research, published in Nature this week, was led by the STAR Institute at the University of Liège, and used the orbiting NASA Spitzer Space Telescope in addition to ground-based facilities including the Liverpool Telescope (LT), owned and operated by Liverpool John Moores University's Astrophysics Research Institute (ARI).
The LT helped to detect the planets as they passed in front of their parent star, the ultracool dwarf star known as TRAPPIST-1. At least three of the planets could harbour oceans of water on their surfaces, increasing the possibility that the star system may play host to life. This system has both the largest number of Earth-sized planets yet found, making it a key object for future study.
Dr Chris Copperwheat, a co-author on the paper, and a member of the ARI, commented on the role of the LT:
“LJMU is at the forefront of the search for other-Earths and the search for other life in the Universe. The Astrophysics Research Institute was delighted to be part of this ground-breaking research using the Liverpool Telescope. The discovery of multiple rocky planets with surface temperatures which allow for liquid water make this amazing system an exciting future target in the search for life."
"As a robotic telescope and the largest in the world, the Liverpool Telescope is very sensitive to the small, less than 1 per cent dips in brightness through which the planets are discovered. It's all automated, it’s flexible and fast, and so is ideal for this sort of time critical work. Supporting the orbiting NASA Spitzer Space Telescope observing schedule, often at very short notice, is a simple task for astronomers who can use our telescope from anywhere in the world.”
The ARI is currently in the process of designing the New Robotic Telescope, a facility which will take the Liverpool Telescope’s crown as the world’s largest robotic telescope dedicated to science, and which will be a powerful tool in the search for other Earths, liquid water and life over the coming decades.
The Liverpool Telescope is one of the largest and most advanced fully robotic telescopes in the world, especially dedicated to the study of variable and transient astronomical phenomena. The timelapse video above shows this giant robot observing the universe at the Instituto de Astrofísica de Canarias (IAC) Roque de los Muchachos Observatory on the summit of La Palma (Canary Islands, Spain), one of the best places on Earth for astronomical observations.
The Liverpool Telescope is mainly used for professional astronomical research, although part of its observational time is devoted to educational projects. In Spain, these are run by the Educational Project with Robotic Telescopes (PETeR) of the IAC, while in the UK, they're run by the National Schools’ Observatory (NSO) at LJMU. The timelapse above is a production of the IAC Communication and Scientific Culture Unit and Daniel López (www.elcielodecanarias.com), with the collaboration of the LJMU Astrophysics Research Institute.
In a paper entitled "Gravitational lens system SDSS J1339+1310: microlensing factory and time delay" currently in preprint at arXiv , authors Luis Julian Goicoechea Santamaria and Vyacheslav Shalyapin reveal how the Liverpool Telescope (LT) has been used to characterise a gravitational lens created by a foreground galaxy in direct line with a much more distant quasar.
Light from the quasar that is heading in the general direction of Earth is passing either side of the foreground galaxy, and is being bent by the galaxy's gravity to meet at a focus at the Solar System.
From Earth we therefore see two images of the quasar, but because each light path takes a slightly different route around the galaxy, one longer than the other, the images are out of sync. Therefore any disturbance or variation in brightness from the quasar will be seen first in one image, and then repeated after some delay in the other image.
The LT data has not only revealed the time delay between both images, and also that the lensing galaxy is causing microlensing with its constituent stars along the light paths from the quasar.
Since 2005, the Gravitational LENses and DArk MAtter (GLENDAMA) team has been conducting optical monitoring of about 10 gravitationally lensed quasars with the LT. For each target, the main goals are to measure time delays between the multiple quasar images, as well as analyse the intrinsic variability of the lensed source and the possible flux variations caused by microlenses (stars) in the lensing galaxy.
After an 8-year monitoring campaign of the double quasar SDSS J1339+1310 in SDSS-R band, the LT light curves of its two images, A and B, are characterised by typical photometric accuracies of 1-2% and an average sampling rate of once every 6 days (excluding gaps).
These light curves show parallel V-shaped variations, which allowed the GLENDAMA team to determine a time delay of 47 days with 10% precision.
In addition, the accurate follow-up observations of both images reveal the presence of significant microlensing-induced flux variations on different timescales, including rapid microlensing events lasting 50-100 days.
While the strong microlensing activity precludes a more accurate estimation of the delay between A and B, the rapid events are very rare phenomena, and thus unique tools for astrophysical studies.
Optical spectra taken with the Gran Telescopio Canarias (GTC) confirm that the system SDSS J1339+1310 is an unusual “microlensing factory”, since appreciable microlensing-induced spectral distortions are also detected.
The paper was accepted in September 2016 for publication in the journal Astronomy & Astrophysics, and is expected to be published soon.