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.

  • Caption: Compilation of the values of λ, measured via the RM effect, as a function of the host star effective temperature (see: http://www.astro.keele.ac.uk/jkt/tepcat/rossiter.html).HAT-P-18b is shown as a filled blue dot. For the two objects marked with
    The measurement of the Rossiter-McLaughlin effect for transiting exoplanetsplaces constraints on the orientation of the orbital axis with respect to the stellar spin axis, which can shed light on the mechanisms shaping the orbital configuration of planetary systems. Here we present the interesting case of the Saturn-mass planet HAT-P-18b, which orbits one of the coolest stars for which the Rossiter-McLaughlin effect has been measured so far. We acquired a spectroscopic time-series, spanning a full transit, with the HARPS-N spectrograph mounted at the TNG telescope. The very precise radial
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  • Caption of the figure: The spectroscopic LF of A85 (gray shadow), blue and red diamonds show the LF of blue and red galaxies of A85. The full lines correspond to the Schecter function fits. The histograms are the LF of field red and blue galaxies (Blanton
    We present a new deep determination of the spectroscopic LF within the virial radius of the nearby and massive Abell 85 (A85) cluster down to the dwarf regime (M*+6) using VLT/VIMOS spectra for ~2000 galaxies with m r ≤ 21 mag and <μ e,r > ≤ 24 mag arcsec -2. The resulting LF from 438 cluster members is best modeled by a double Schechter function due to the presence of a statistically significant upturn at the faint-end. The amplitude of this upturn (α f = -1.58 +0.19 -0.15), however, is much smaller than that of the SDSS composite photometric cluster LF by Popesso et al. (2006, α f ~-2)
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  • Figure caption: Left panels show the i − J vs. g − r diagrams for three different parameters: surface brightness in restframe J (μJ, blue), the logarithm of the stellar mass density (log (ρ), pink), and the radial distance to the most massive galaxies of
    The ultra-deep multiwavelength Hubble Space Telescope Frontier Fields coverage of the Abell Cluster 2744 is used to derive the stellar population properties of its intracluster light (ICL). The restframe colors of the ICL of this intermediate redshift (z = 0.3064) massive cluster are bluer (g – r = 0.68 ± 0.04; i – J = 0.56 ± 0.01) than those found in the stellar populations of its main galaxy members (g – r = 0.83 ± 0.01; i – J = 0.75 ± 0.01). Based on these colors, we derive the following mean metallicity Z = 0.018 ± 0.007 for the ICL. The ICL age is 6 ± 3 Gyr younger than the average age
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  • Our visible and NIR spectropolarimetric measurements of the earthshine compared to literature data. A 10-pixel binning was applied to the NIR spectrum. The uncertainty per wavelength is plotted as vertical gray error bars. Wavelengths of strong telluric a
    Aims. We aim to extend our current observational understanding of the integrated planet Earth spectropolarimetry from the optical to the near-infrared wavelengths. Major biomarkers like O2 and water vapor are strong flux absorbents in the Earth’s atmosphere, and some linear polarization of the reflected stellar light is expected to occur at these wavelengths. Methods. Simultaneous optical (0.4−0.9 μm) and near-infrared (0.9−2.3 μm) linear spectropolarimetric data of the earthshine were acquired by observing the nightside of the waxing Moon. The data have sufficient spectral resolution (2.51
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  • Figure:  GTC/ORISIS Spectroscopy. Upper Panel: 2-D spectral image. Center Panel: Obj1. Lower Panel: Obj2. The Lyα lines, marked with a red line, are clearly seen in both spectra. The blue dashed line, at the bottom of each frame, shows an off-scale sky sp
    We are undertaking a search for high-redshift low-luminosity Lyman Alpha sources in the SHARDS (Survey for High-z Absorption Red and Dead Sources) survey. Among the pre-selected Lyman Alpha sources two candidates were spotted, located 3.19 arcsec apart, and tentatively at the same redshift. Here, we report on the spectroscopic confirmation with Gran Telescopio Canarias of the Lyman Alpha emission from this pair of galaxies at a confirmed spectroscopic redshifts of z=5.07. Furthermore, one of the sources is interacting/merging with another close companion that looks distorted. Based on the
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  • Figure Caption: Teff and log gc estimates for the Galactic (red circles) and LMC (gray triangles) O-type dwarfs as a function of SpT; corresponding linear fits are overplotted with red and black dashed lines.  The figures show the scatter found in effecti
    We are now in an era of large spectroscopic surveys of OB-type stars. Quantitative spectroscopic analysis of these modern datasets is enabling us to review the physical properties of blue massive stars with robust samples, not only revisiting mean properties and general trends, but also incorporating information about the effects of second-order parameters. We investigate the spectral type -- effective temperature (SpT - Teff) calibration for O-type dwarfs, and its claimed dependence on metallicity, using statistically-meaningful samples of stars extracted from the IACOB and VFTS surveys. We
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