Warwick astronomers celebrate first light from 4MOST
The 4-metre Multi-Object Spectroscopic Telescope (4MOST), the largest multi-object spectroscopic survey facility in the southern hemisphere, has taken its first observations and is ready to begin its scientific journey.
4MOST, installed at the European Southern Observatory’s Paranal Observatory in Chile, is now ready for operation. Unlike traditional telescopes that take images of the sky, 4MOST records spectra – capturing the light of objects in the sky in every colour.
University of Warwick Professor, Pier-Emmanuel Tremblay, will lead two sub-surveys, one aiming to collect medium-resolution optical spectra for all the 200,000 stars located within about 330 light-years (100 parsecs) of the Sun that are visible from Chile. The other targeting the 150,000 white dwarfs discovered by the European Space Agency’s Gaia mission. Warwick is collaborating with the international 4MOST project, supported by funding from the European Research Council.
“The population of stars and planetary systems close to the Sun remains surprisingly underexplored,” says Professor Pier-Emmanuel Tremblay, Astronomy and Astrophysics Group, University of Warwick. “These nearby objects will be the targets of our 4MOST sub-surveys. They are the brightest in the sky for their classes and can be studied across the full range of light, without the interference of dust. They serve as essential reference points for testing our models of how stars and planets evolve, and for calibrating astronomical instruments.”
Warwick has also contributed to pipeline development for 4MOST. In particular, Dr Ingrid Pelisoli acted as the Quality Control Scientist and subsequently led and set up the Data Quality Control Working Group. This team works behind the scenes performing manual and automated checks of the data to ensure everything is working as expected before spectra are shared with astronomers around the globe. After handing over leadership of the group to focus on science, Dr Pelisoli now co-leads the hot subdwarf sub-survey, which will study these special stars that can only be created by binary interaction.
Dr. Ingrid Pelisoli, Assistant Professor and Royal Society University Research Fellow, Astronomy and Astrophysics Group, University of Warwick, adds: “It takes a lot of work to convert the light captured by 4MOST’s fibres into numerical values of flux as a function of wavelength – which is the format of the spectral data that astronomers need for their analysis.
“There are many calibration steps that can go wrong along the way. Data quality control is crucial to identify and correct any issues before the data are used for science, and to ensure people can have confidence in their results. I’m very excited to see the Data Quality Control Working Group that I set up finally performing their role with real data, and I can’t wait to see what discoveries that will enable.”
4MOST provides a unique combination of large field of view, number of simultaneous observed objects, and number of spectral colours simultaneously registered and the First Light observations exemplify the unique capabilities showing a very large field of view with many very different objects and science cases viewed simultaneously in great detail.
Once fully operational, 4MOST will investigate the formation and evolution processes of stars and planets, the Milky Way and other galaxies, black holes and other exotic objects, and of the Universe as a whole. By analysing the detailed rainbow-like colours of thousands of objects every 10–20 minutes, 4MOST will build a catalogue of temperatures, chemical compositions, velocities and many more physical parameters of tens of millions of objects spread across the entire Southern sky.
4MOST Principal Investigator Roelof de Jong, Milky Way section head at AIP, remarks: “It is incredible to see the first spectra from our new instrument. The data look fantastic from the start and bode well for all the different science projects we want to execute. That we can catch the light that has travelled sometimes for billions of light years into a glass fibre the size of a hair is mindboggling. An incredible feat only made possible by an incredible development team. I can't wait to have the system operating every night.”
ENDS
Notes to Editors
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Images & Video captions and credits
The First Light video from 4MOST is credited to - AIP/R. de Jong, AIP/K. Riebe, AIP/A. Saviauk, CRAL/J.-K. Krogager - and can be watched here
VISTA 4MOST - The 4MOST instrument is installed at the VISTA telescope in Chile. Credit: AIP/A. Saviauk
4MOST-Spectra-FOV - The sky around the Sculptor Galaxy NGC 253 and the globular cluster NGC 288 was the target of the first observations with 4MOST. The blue frame shows the boundary of 4MOST's field of view. Each circle symbolises one of the more than 2400 fibres. The embedded images show the spectrum of a star (right) and the spectrum of a globular cluster in the Sculptor Galaxy (left). Credit: AIP/R. de Jong, Centre de Recherche Astrophysique de Lyon/J.-K. Krogager, Background: Harshwardhan Pathak/Telescope Live
VISTA Mountain Top - ESO’s astronomical facilities in Chile are hives of activity — or oases! — in the otherwise barren and arid landscape of the Atacama Desert. This hostile and hard-to-reach location may seem like an odd choice for construction, but the Atacama is one of the best sites in the world for astronomy. It has practically no cloud cover, a distinct lack of light pollution, and is the driest non-polar location in the world, receiving under two centimetres of rainfall every year! Chile has hosted ESO’s telescopes since the 1960s, in observatories based at La Silla, Paranal, and Chajnantor Plateau. Shown here is the Visible and Infrared Survey Telescope for Astronomy (VISTA), situated at the Paranal Observatory. Perched atop a mountain adjacent to Cerro Paranal, the home of the flagship Very Large Telescope (VLT), VISTA is the largest telescope in the world designed to survey the sky in near-infrared light (just beyond that visible to humans). The spectacular sights of the cosmos — including the notable streak of our home galaxy, the Milky Way, stretching across the top of the frame here — are more than enough to keep VISTA and its telescopic siblings busy. Credit: ESO/B. Tafreshi (twanight.org)
Thumbnail - 4MOST-Spectrum - Sky region of the first observations with 4MOST with an example spectrum. In the Sculptor Galaxy (top right), 4MOST took spectra from its centre, star-forming regions and globular clusters. The old stars of the globular cluster NGC 288 (bottom left) from the outskirts of our Milky Way showed hardly any signatures of heavy elements. The coloured line in the image corresponds to spectrum captured with 4MOST of a distant galaxy with an active nucleus. Credit: AIP/R. de Jong, CRAL/J.-K. Krogager, Background: Harshwardhan Pathak/Telescope Live
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About the 4MOST Consortium
The 4MOST facility is designed, built, and scientifically operated by a Consortium of 30 universities and research institutes in Europe and Australia involving 700 investigators under leadership of the Leibniz Institute for Astrophysics Potsdam (AIP). In its first five years of operations, 4MOST will conduct 25 different science programmes. Uniquely, the multi-fibre nature of 4MOST enables many science programmes to be observed simultaneously.
About the 4MOST facility
The 4-metre Multi-Object Spectroscopic Telescope (4MOST) facility is installed on the VISTA telescope at the European Southern Observatory’s (ESO) Paranal Observatory in Chile. Development started in 2010, and the facility has been designed to operate for at least the next 15 years. At the heart of the system, 4MOST uses 2438 optical fibres, each the size of a human hair, to catch the light of celestial objects. Light from each of these fibres is transported to the spectrographs that break up the light in its different colours. 4MOST will observe a new set of objects in the sky every 10–20 minutes using a fibre positioner that moves all fibres to observe new objects in less than 2 minutes.
About the First Light Observations
One of the objects dominating the First Light observation of 4MOST is the elongated galaxy NGC253, also called the Sculptor or Silver Coin galaxy. Except for the Magellanic Clouds, it is the galaxy with the largest apparent diameter in the southern sky with nearly the same diameter as the moon, only much fainter. It was discovered by Caroline Herschel in 1783, is at a distance of about 11.5 million lightyears, and is known to currently form a lot of new stars. The 4MOST observations also capture a super star cluster, various hot and cold stars and their movements, and gas glowing from newly formed stars in this galaxy.
The other large object seen in the field is the Globular Cluster NGC288, a very dense group of about 100,000 very old stars in the outskirts of the Milky Way. It formed about 13.5 billion years ago in the very earliest phases of the formation of the Milky Way. Its stars contain very small amounts of most chemical elements heavier than hydrogen and helium, reflecting its pristine composition.
Next to these two very large objects, 4MOST obtained spectra of more than two thousand other objects in its first science observation. These include spectra of a large variety of bright and faint stars in our Milky Way, allowing scientists to determine their temperature, mass, diameter, velocity, age and evolutionary stage, and chemical composition. Beyond the Milky Way, spectra of a pair of overlapping galaxies at 900 million lightyears were obtained, as well as spectra of more than a thousand other galaxies near and far – up to 10 billion lightyears! – to determine their distance, internal velocity, and star formation history or the mass of their central black hole.