This section includes scientific and technological news from the IAC and its Observatories, as well as press releases on scientific and technological results, astronomical events, educational projects, outreach activities and institutional events.

  • Photometric magnetic activity index, Sph, as a function of the Rossby for the Kepler stars showing the comparison between an older relation to compute the Rossby number (left panel, Noyes 1984) and the Rossby number from this work (right panel).

    In a star like the Sun, surface magnetic activity results from the interaction between rotation, convection, and magnetic field. One of the key parameters to study the magnetic activity of stars is the Rossby number, which is the ratio between the surface rotation period of the star and the convective turnover time. The convective turnover time measures the time that takes a bubble of plasma to go from the base of the convective zone in a star like the Sun to the surface, similarly to a bubble reaching the surface in a pan with boiling water heated by the bottom. While the surface rotation

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  • Linear polarization pattern of the solar D1 and D2 spectral lines, comparing observations to the results of the modeling (see legend). An excellent agreement with observations is found when assuming that the solar atmosphere is significantly magnetized.

    In 1998 the journal Nature published a seminal letter concluding that the mysterious polarization (a particular property of light) that had been recently observed in the solar sodium D1 line implies that the solar chromosphere (a very important layer of the solar atmosphere) is practically unmagnetized, in sharp contradiction with common wisdom. This paradox motivated laboratory experiments and theoretical investigations which, instead of providing a solution, raised new issues and even led some scientists to question the quantum theory of radiation-matter interaction. Here, we have carried

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  • Result of the field test made with the copy of DRAGO on September 22nd 2021 at 08.00 local time.

    The eruption on La Palma has provided a unique scenario for testing the DRAGO instrument, the infrared camera of the Instituto de Astrofísica de Canarias (IAC) which has been observing the Canary Islands from space since January. One of the objectives for which DRAGO was designed is monitoring natural disasters, especially those which could occur in the Canaries, such as forest fires, petroleum spills, or volcanic eruptions. The role of DRAGO is to provide infrared images from space to help the management and control of these disasters. In the case of the eruption which began on September

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  • Logo del IAC

    The Instituto de Astrofísica de Canarias wants to extend its solidarity and support to the island of La Palma, to all who are suffering the consequences of the volcanic eruption, and especially to those who had to abandon their homes or have suffered damages to their properties. We share the pain that this has caused them and the wish for the circumstances to change for the better as soon as possible. The authorities and all the institutions involved in the emergency plan have the material and staff resources of the IAC at their disposal for whatever they consider necessary.

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  • Ratio between the measured and predicted gravitational redshifts vs. cosmological redshift, zcosm. Main panel: data from the present work. Superior inset: Solar System and Milky Way data from the literature. Inferior inset: galaxy cluster data from the literature (see Figure 1 of the paper).

    We perform a new test of Einstein's Equivalence Principle which, for the first time, extends to very early cosmological epochs (we have studied its validity in 80% of the history of the Universe). The Einstein Equivalence Principle is essential for generalizing physical laws in the presence of gravity. Our test of the Equivalence Principle is based on one of Einstein's classical predictions: the gravitational redshift of photons. This test has been accurately put into practice in our Solar System and in some stars in our Galaxy (e.g. Sirius B). However, so far it has not been applied to

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  • Image taken by the Hubble Space Telescope of the Einstein ring GAL-CLUS-022058s, located in the constellation of Fornax. Credit: ESA/Hubble & NASA, S. Jha; Acknowledgment: L. Shatz

    In December 2020 a team from the European Space Agency (ESA) published an image taken by the Hubble Space Telescope (HST) of GAL-CLUS-022058s, the biggest and one of the most complete Einstein rings discovered, situated towards the southern hemisphere constellation of Fornax. Since then, those observations have been used to develop a model of gravitational lenses which has enabled the study of the physical properties of the amplified galaxies.

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