CAVITY publishes 3D data of 100 galaxies in voids of the Universe observed from Calar Alto
In 2020, the Calar Alto Observatory Scientific Advisory Committee selected three major observational programs to be carried out with the 3.5-meter telescope, the largest of its kind in European mainland. The idea was to offer hundreds of observing nights so as to complete ambitious projects aiming at answering major questions of modern astrophysics, such as the omnipresence of (habitable?) planets around dwarf stars other than the Sun (KOBE and CARMENES-LEGACY+ projects) as well as the formation and evolution of galaxies in the Universe (CAVITY project).
CAVITY (Calar Alto Void Integral-field Treasury surveY) is dedicated to scrutinize in detail hundreds of galaxies located in the less dense areas of the local universe, i.e., less populated in other galaxies. Galaxies are gigantic concentrations of stars, as our Sun is a small star among the hundred billion(s) of the Milky Way. They are usually surrounded, a few million light-years away, by other galaxies in the large-scale "sponge-like" distribution in the Universe of both visible and invisible (the so-called dark) matter inherited from the Big Bang.
Indeed, galaxies are not randomly distributed in the Universe, but they form a huge structure with sponge-like filaments, following the distribution of dark matter. This gives rise to large clusters of galaxies, in which the density is such that interactions and collisions between galaxies are frequent. There are also regions, the "bubbles" of the sponge, where there is hardly any mass concentration and which present a more pristine environment, free from the large interactions of the clusters.
These cosmic voids, little studied so far, nonetheless represent the ideal environment to better understand how galaxies evolve on their own, making easier to understand their formation, which are two of the great questions of modern cosmology. CAVITY is a pioneering project that aims at understanding the role of the large-scale structure of the Universe in the formation and evolution of galaxies, by studying in detail the systems that inhabit those cosmic voids.
The essential source of data for the CAVITY project comes from Calar Alto observatory, where thousands of two-dimensional spectra from PMAS, an instrument of the 3.5 m telescope, are being obtained, in addition to data taken at other large astronomical infrastructures. PMAS is a large integral-field unit spectrograph, developed 20 years ago at the Leibniz-Institut für Astrophysik Potsdam (AIP) and still very competitive thanks to its wide field-of-view that allows us to study in detail the galaxies in the local universe, from their central to their outer regions: in a single exposure, spectra covering the entire visible range of more than 300 regions of a galaxy are taken. The PMAS observations of more than a hundred void galaxies have already been successfully completed for CAVITY.
"The ultimate goal is to achieve unprecedentedly varied and crucial data for 400 galaxies in cosmic voids," explains Isabel Pérez Martín, full professor at the Theoretical and Physics of Cosmos dept. at Granada University, who leads this project. CAVITY involves 50 researchers from 13 national and international institutions.
CAVITY spiral galaxy No. 62480 as observed with the 3.5 m CAHA telescope. (a) Top: image in the visible range rebuilt from the PMAS data cube. (b) Middle: spectrum of the PMAS fiber located on the nucleus of the galaxy, with its characteristic emission (~ gas) and absorption (~ stars) lines, unique "barcode" that allows us to infer, among others properties, (c, bottom left) the gas velocity in this galaxy (clear rotation, from the red areas towards the blue areas); and (d, bottom right) the average age of the stellar population, with younger stars (blue-green color, about 1 billion years old) in the outer regions (spiral arms) and older stars concentrated in the central region (the nucleus appears in yellow, stars with ages of about 10 billion years). Credits: CAVITY project.
On July 15th, 2024, CAVITY publishes its first data release or "DR1" (for Data Release 1) making available to the entire scientific community the two-dimensional spectra of a first sample of 100 galaxies observed at the 3.5 m telescope with PMAS, data ready for an immediate use. Astronomers from all over the world can download these PMAS data cubes from 12:00 noon (Spanish mainland time) this day to perform their own exhaustive analysis. "The information available allows us to cover a wide range of galaxy properties, including brightness, color, mass and morphology," explains Isabel Pérez, CAVITY prime investigator at the University of Granada.
The access to the database is done from the project website, which encourages collaboration and sharing of knowledge among researchers, although its legacy nature goes well beyond professionals, and anyone interested will be able to access the data.
Jesús Aceituno, director of the observatory, emphasizes that "this first public release of CAVITY data, one of the three major legacy programs underway at Calar Alto, shows once again the commitment of the Centro Astronómico Hispano en Andalucía with the national and international scientific community, offering hundreds of observing nights to large observational projects, the hallmark of the observatory".
Top: Large-scale distribution of galaxies (black dots) projected on the sky (left) and in the third dimension (cone with approximate distances via the redshift of each galaxy). The filamentary structure of the Universe is clearly visible and the different voids studied in CAVITY are highlighted in color. Bottom right right: 3D distribution of CAVITY galaxies in one of these voids (No. 487, in blue in the upper maps) color-coded according to the redshift (~ distance) to our own galaxy (blue = closest, red = farthest). To the left, huge "zoom in" on one of these galaxies (No. 32817), showing an actual image of the field of that spiral galaxy, obtained by the large sky survey Sloan Digitized Sky Survey. Credits: CAVITY and SDSS.
NOTE: CAVITY is funded by MICIN/AEI through project PID2020-113689GB-100, the Consejería de Universidad, Investigación e Innovación de la Junta de Andalucía, the Government of Spain, the European Union -- NextGenerationEU through AST22.4.4, and the University of Granada. Based on data obtained at Centro Astronómico Hispano in Andalucía.
Isabel Pérez Martín This email address is being protected from spambots. You need JavaScript enabled to view it.
Calar Alto Observatory
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COMUNICATION – CALAR ALTO OBSERVATORY
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The Calar Alto Observatory is one of the infrastructures that belong to the national map of Unique Scientific and Technical Infrastructures (Spanish acronym: ICTS), approved on March 11th, 2022, by the Science, Technology and Innovation Policy Council (CPCTI).
English (UK)
In 2020, the Calar Alto Observatory Scientific Advisory Committee selected three major observational programs to be carried out with the 3.5-meter telescope, the largest of its kind in European mainland. The idea was to offer hundreds of observing nights so as to complete ambitious projects aiming at answering major questions of modern astrophysics, such as the omnipresence of (habitable?) planets around dwarf stars other than the Sun (KOBE and CARMENES-LEGACY+ projects) as well as the formation and evolution of galaxies in the Universe (CAVITY project).
