News

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.

  • Top panel: orbital phase shift at the time of the inferior conjunction (orbital phase 0), Tn, of the secondary star in the black hole X-ray binary Nova Muscae 1991 versus the orbital cycle number, n, folded on the best-fitting parabolic fit. The error bar
    We present new medium-resolution spectroscopic observations of the black hole X-ray binary Nova Muscae 1991 taken with X-Shooter spectrograph installed at the 8.2-m VLT telescope. These observations allow us to measure the time of inferior conjunction of the secondary star with the black hole in this system that, together with previous measurements, yield an orbital period decay of (dP/dt)= −20.7±12.7 ms yr −1 (−24.5 ± 15.1 μs per orbital cycle). This is significantly faster than those previously measured in the other black hole X-ray binaries A0620-00 and XTE J1118+480. No standard black
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  • Ks/F814W flux ratio (or extinction map) with emission line contours of the [OIII] gas in green. The brighter regions denote higher extinction and hence dust absorption. The conical morphology of the ionized gas is clearly defined by a horned-shaped dust s
    In some AGN, nuclear dust lanes connected to kpc-scale dust structures provide all the extinction required to obscure the nucleus, challenging the role of the dusty torus proposed by the Unified Model. In this letter we show the pc-scale dust and ionized gas maps of Circinus constructed using sub-arcsec-accuracy registration of infrared VLT AO images with optical Hubble Space Telescope images. We find that the collimation of the ionized gas does not require a torus but is caused by the distribution of dust lanes of the host galaxy on ~10 pc scales. This finding questions the presumed torus
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  • Two extracted GTC light curves in the wavelength ranges indicated at the legend, showing several eclipse events that have comparable depths in all the different colors.
    During the last decades, growing evidence about the presence of planetary material around white dwarfs has been established. The features of heavy elements in the spectra of a large fraction (25-50%) of these objects needs a frequent accretion of material orbiting close to the white dwarf. Additionally, at least 4% of these objects are known to host dusty disks. The space mission K2, that re-uses the Kepler instrument after a failure of two of its four gyroscopes, recently detected transiting material around WD1145+017, with periods in the 4.5-5h range, and a depth variability with scales of
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  • Dust continuum emission at 694 GHz (432 μm) mapped by ALMA in the CND of NGC 1068. The right panel shows a close-up of the dust continuum emission shown in left panel.
    NGC 1068 is the prototypical Seyfert 2 galaxy and a prime example for active galactic nuclei (AGN) unifying schemes. Its central engine is thought to be hidden behind a screen of obscuring material located in a dusty molecular torus of a few parsecs size. Given the distance to the galaxy (D ∼ 14 Mpc), it has been the subject of tens of studies aiming to disentangle what is happening in its central parsecs. We used the Atacama Large Millimeter Array (ALMA) to map the emission of the CO(6–5) molecular line and the 432 μm continuum emission from the 300 pc sized circumnuclear disk (CND) of the
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  •  Left panel: SINFONI data cube collapsed in the spectra dimension, where bot the interloper and Aql X-1 are clearly resolved. Right panel: averaged, normalized spectra obtained for each object.
    Low mass X-ray binaries consist of two components: a compact object (either a neutron star or a stellar-mass black hole) and a star with a mass similar or lower to that of the Sun. Both objects are close enough for the gravity to strip material from the companion star, which fall onto the compact object forming an accretion disc. Indeed, both objects are so close (typically less than three times the orbit of Mercury) that not even the most powerful telescope can spatially resolve them. Aquila X-1 (Aql X-1) is a canonical X-ray binary harbouring a neutron star. Since its discovery 40 years
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  • Strength of the large-scale magnetic field in nearby galaxies vs. their rotation speed.
    Magnetic fields are present on all scales in the Universe from planets and stars to galaxies and galaxy clusters, and even at high redshifts. They are important for the continuation of life on the Earth, the onset of star formation, the order of the interstellar medium, and the evolution of galaxies. Hence, understanding the Universe without understanding magnetic fields is impossible. The origin and evolution of cosmic magnetic fields is among the most pressing questions in modern astronomy. The most widely accepted theory to explain the magnetic fields on stars and planets is the α-Ω
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