“High Performance computing of massive astrometry and photometry data from Gaia” is the first Ph.D. thesis dedicated to the initial data processing of real data of the Gaia mission. The author is Javier Castañeda, researcher at the Institute of Cosmos Sciences (IEEC-UB). It will have its defense on 15 December 2015 at the Facultat de Física, Universitat de Barcelona.Gaia_spacecraft_illustration_625 Gaia is an extremely ambitious astrometric space mission adopted within the scientific programme of the European Space Agency (ESA) in October 2000. It aims to measure with very high accuracy the positions, motions and parallaxes (distances) of more than a billion stars and Galactic objects. it also includes information about their brightness, colour, radial velocity, orbits and astrometric parameters. Gaia requires a very demanding data processing system on both data volume and processing power. The treatment of the Gaia data has been designed as an iterative process of several systems, each one solving different aspects of the data reduction process. In this thesis, Javier Castañeda, under the supervision of Claus Fabricius and Jordi Torra, addresses the design and implementation of the Intermediate Data Updating (IDU) system. IDU is the most demanding instrument calibration and data processing system, in data volume and processing power of Gaia. Without this system Gaia would not be able to provide the envisaged high accuracies. IDU is fundamental to achieve the optimum convergence of the iterative process on which all the data processing of the spacecraft is based.

At University of Barcelona, the anual science video for this current year has been dedicated to the light. It is an initiative to commemorate the 2015 year of Light. In the video, the ICCUB member Carme Jordi explains, in a very didactic way, the characteristics of stars light, the importance of its study and all the relevant information we can extract from this light source. To see the video please go to the link below

This GaiaUB image of the Gaia's focal plane was selected as the image of the week on the ESA's Gaia page.

To optimise the transmission of light from the vacuum of space into the silicon of the light detectors, the silicon is covered with a very thin anti-reflective (AR) coating. The thickness chosen for that layer depends on the wavelength range which is to be observed with a particular CCD detector.

The model of the CCDs used for that purpose does not only allow to determine the amount of light that is absorbed by the CCDs as a function of wavelength, but also to compute the fraction of light reflected from its surface. Using the latter information, it is possible to compute the colour of the CCDs as a human being would see them, as a function of the thickness of the AR coating. The colour of the Gaia's eyes.

The small frame in the image shows the colour in which a human being would see a Gaia CCD as a function of thickness of the AR coating.

Credits: ESA/Gaia/Airbus DS/DPAC/IEEC-ICCUB/M.Weiler

The Total Lunar eclipse that took place on the on the night of September 27-28 was perfectly visible from Catalonia. ServiAstro offered the live broadcast of the event. On this page you can find all the images of the broadcast and some other pictures of the event.

Last Friday, 21 August, ESA’s billion-star surveyor, Gaia, completed its first year of science observations in its main survey mode. After launch on 19 December 2013 and a six-month long in-orbit commissioning period, the satellite started routine scientific operations on 25 July 2014. Located at the Lagrange point L2, 1.5 million km from Earth, Gaia surveys stars and many other astronomical objects as it spins, observing circular swathes of the sky. At the end of 28 days period for the initial calibration of the instruments, on 21 August, Gaia commenced its main survey operation, employing a scanning law designed to achieve the best possible coverage of the whole sky. Since then, the satellite recorded 272 billion positional or astrometric measurements, 54.4 billion brightness or photometric data points, and 5.4 billion spectra.The Gaia team have spent a busy year processing and analysing these data, en route towards the development of Gaia’s main scientific products, consisting of enormous public catalogues of the positions, distances, motions and other properties of more than a billion stars. Because of the immense volume of data and their complex nature, this requires a huge effort from expert scientists and software developers distributed across Europe, combined in Gaia’s Data Processing and Analysis Consortium (DPAC). The group composed by about forty researchers and engineers from the University of Barcelona (UB), together with the Galician Group for Gaia and a group of experts from the Spanish National University for Distance Education (UNED).Carme Jordi, researcher in the Institute of Cosmos Sciences of the UB (ICCUB-IEEC), affirms: “This first year has been crucial to test the scientific quality of data and the effectiveness of processing algorithms. Particularly, our team is responsible for initial data treatment and it has surpassed expectations in the management of the great volume of information”.As one example of the ongoing validation, the Gaia team has been able to measure the parallax for an initial sample of two million stars. Parallax is the apparent motion of a star against a distant background observed over the period of a year and resulting from the Earth's real motion around the Sun; this is also observed by Gaia as it orbits the Sun alongside Earth. But parallax is not the only movement seen by Gaia: the stars are also really moving through space, which is called proper motion.Only one year of observations is generally not enough to disentangle the parallax and proper motions. To overcome this, the scientists have combined Gaia data with positions extracted from the Tycho-2 catalogue, based on data taken between 1989 and 1993 by Gaia's predecessor, the Hipparcos satellite. This restricts the sample to just two million out of the more than one billion that Gaia has observed so far, but yields some useful early insights into the quality of its data.Gaia has detected hundreds of transient sources so far, with a supernova being the very first on 30 August 2014. These detections are routinely shared with the community at large as soon as they are spotted in the form of ‘Science Alerts’, enabling rapid follow-up observations to be made using ground-based telescopes in order to determine their nature.One transient source was seen undergoing a sudden and dramatic outburst that increased its brightness by a factor of five. It turned out that Gaia had discovered a so-called ‘cataclysmic variable’, a system of two stars in which one, a hot white dwarf, is devouring mass from a normal stellar companion, leading to outbursts of light as the material is swallowed.Gaia has also discovered a multitude of stars whose brightness undergoes more regular changes over time. The satellite has delivered detailed light curves for dozens of RR Lyrae type variable stars in the Large Magellanic Cloud, and the fine details revealed in them testify to the very high quality of the data.Another curious object covered during the same mission phase is the Cat’s Eye Nebula, a planetary nebula also known as NGC 6543, which lies close to the north ecliptic pole. Planetary nebulae are formed when the outer layers of an aging low-mass star are ejected and interact with the surrounding interstellar medium, leaving behind a compact white dwarf. Gaia made over 200 observations of the Cat’s Eye Nebula, and registered over 84 000 detections that accurately trace out the intricate gaseous filaments that such objects are famous for. As its observations continue, Gaia will be able to see the expansion of the nebular knots in this and other planetary nebulae.Closer to home, Gaia has detected a wealth of asteroids, the small rocky bodies that populate our solar system, mainly between the orbits of Mars and Jupiter. Gaia scientists have developed special software to look for these ‘outliers’, matching them with the orbits of known asteroids in order to remove them from the data being used to study stars. But in turn, this information will be used to characterise known asteroids and to discover thousands of new ones.Finally, in addition to the astrometric and photometric measurements being made by Gaia, it has been collecting spectra for many stars. The basic use of these data is to determine the motions of the stars along the line-of-sight by measuring slight shifts in the positions of absorption lines in their spectra due to the Doppler shift. But in the spectra of some hot stars, the satellite has also seen absorption lines from gas in foreground interstellar material, which will allow the scientists to measure its distribution. “These examples prove the revolution brought by the Gaia mission to astrophysics. We are looking forward for the publication of first scientific data in the summer of 2016”, emphasizes Edard Masana, researcher in the ICCUB-EEC. UB participation in the missionThe Gaia UB team is composed by researchers from the Institute of Cosmos Sciences of the University of Barcelona (ICCUB), the Institute of Space Studies of Catalonia (IEEC) and the Department of Astronomy and Meteorology of the UB. The team has been involved in the Gaia mission since the very early phases. It has played a major role in the scientific and technological design of the instrumentation, database prototypes and data simulation. It has also developed a calibration algorithm of photometric data, and the system that will enable to daily process satellite’s data and store them in a database to later extract the first scientific results.Furthermore, the group is developing tools for scientific exploitation, by means of data got from the Earth in order to complement those provided by Gaia. The Data Processing Center of Barcelona, which includes CESCA and the Barcelona Supercomputer Center, provides resources to carry out some operations throughout the mission and has been a necessary tool to carry out simulations in order to test the instrument.

For further information, please click on ESA’s press release.

Gaiaverse is a multilingual portal aimed at disseminating information about the Gaia mission generated in every country or institution involved in the project. The portal is managed by researchers at the Institute of Cosmos Sciences of the University of Barcelona (ICCUB-IEEC). The portal is part of the project GENIUS, a European project in which ICCUB collaborates. GENIUS aims at becoming a hub of Gaia’s spreading knowledge by collecting all kind of divulgation materials such as presentations, videos, posters, brochures, tools, news… which are all available through this portal, Gaiaverse. Eduard Masana, ICCUB researcher, is one of the members of the editorial board that validate the contents of the portal. Information is available in six languages: English, French, German, Italian, Spanish and Catalan. Link to Gaiaverse The Montsec Observatory and Gaia alerts One of the first pieces of news published in the portal describes the use of the robotic telescope Joan Oró at the Montsec Observatory (OAdM), located at Àger (Lleida, Spain), by ICCUB researchers within a ground-based follow-up programme to monitor the evolution of transient objects detected by Gaia. Alerts are activated when Gaia detects a source increasing their brightness with respect to previous observations. A procedure designed on a project developed within the master’s degree in Astrophysics, Particle Physics and Cosmology of the UB, transfer information to the robotic telescope for ground observations. From February 2015 when the programme was activated, a total of about 1400 images in multicolor Johnson-Cousins passbands were obtained with the telescope Joan Oró for 17 Gaia science alerts. This makes OAdM the third most contributing observatory among all of the participants in the Gaia photometric science alert project.

On 15 and 16 July 2015, the Cherenkov Telescope Array (CTA) Resource Board decided that the Roque de los Muchachos observatory, on La Palma, will soon host its major scientific installation in the northern hemisphere. CTA will be a scientific infrastructure composed of two observatories, one in each hemisphere, consisting of a network of new generation Cherenkov telescopes which will enable the study of very high energy gamma rays. The network will consist of 100 telescopes, from which about 20 of them will be installed around several places in the northern hemisphere. The ICCUB participates in the CTA project since its inception and has welcomed many working meetings of the network. ICCUB researchers have been contributing to the Physics and electronics by making simulations of the observations that the CTA will perform of Gamma Ray Binaries. Besides they made a proposal for observing transient galactic objects beneath one of the Key Observation Projects from CTA. As Marc Ribó from ICCUB explains "The ICCUB and the University of Barcelona, will participate in short in the discussion of the many different CTA scientific cases of study and also in the development of technology and integrated electronics. Later on, when CTA is fully working, we will contribute to the examination of the scientific data, which will be managed by the CTA consortium (an entity to which ICCUB researchers belong)." "Being part of CTA –says the researcher– will also give us the oportunity of upgrading, in the future, the electronics of the cameras with new photomultipliers."

For the first time, six research units (most of them university-dependant institutions) have become part of the elite which leads the most advanced scientific research studies in our country. The six centers, including the Institute of Cosmos Sciences from the University of Barcelona, have been awarded the recognition "Maria de Maeztu" from the Ministry of Economy and Competitiveness. This distinction will open the doors to new hiring opportunitites, both for experienced reserachers and for doctorate students. The half milion euros dotation of the programme, will specially help to the development and growing of research institutions which belong to the academia. It is a fact that more thant the 50% of the excellence scientific production in Spain comes from universities. However, as Lluís Garrido (ICCUB director) noted, the scientific production of a university is usually evaluated as a whole which makes the excellence research carried there to go unseen and hence to be misappreciated. For the next four years, the awarded institutions will become members of the scientific research dream-team and have the recognition they deserve, appart from the necessary fundings for keeping doing their outstanding labour.

The Gravity Research Foundation was founded by Roger W. Babson (1875- 1967) and the first awards for the best essays submitted on Gravity were made on December 1st, 1949. Since then, each edition has been a high level competition among scientists from all over the world, many times being the winners reputated scientists previously awarded Nobel Prizes. This year the ICCUB member, Joan Solà and the ICCUB collaborator Paul Towsend, have been selected for Honorable Mention, and their respective essays would be publish in a special number of the Gravity Research Foundation journal. Remarkable are also the 2 previous editions in which Dr. Solà was also recognized with this same mention. This third consecutive year it has been his essay titled "The cosmological constant and entropy problems: mysteries of the present with profound roots in the past" which has made him to receive again the honour mention.