Does a relativistic metric generalization of Newtonian gravity exist in 2+1 dimensions?

It is shown that, contrary to previous claims, a scalar tensor theory of Brans-Dicke type provides a relativistic generalization of Newtonian gravity in 2+1 dimensions. The theory is metric and test particles follow the space-time geodesics. The static isotropic solution is studied in vacuum and in regions filled with an incompressible perfect fluid. It is shown that the solutions can be consistently matched at the matter vacuum interface, and that the Newtonian behavior is recovered in the weak field regime.Comment: 6 pages, no figures, Revtex4. Some discussions on the physical nature of the interior solution and on the omega->infinity limit and some references added. Version to appear in Phys. Rev.

Editorial : expo ESA, el sector espacial al alcance de la mano

Peer Reviewe

The VVV near-IR galaxy catalogue in a Northern part of the Galactic disc

The automated identification of extragalactic objects in large surveys provides reliable and reproducible samples of galaxies in less time than procedures involving human interaction. However, regions near the Galactic disc are more challenging due to the dust extinction. We present the methodology for the automatic classification of galaxies and non-galaxies at low Galactic latitude regions using both images and, photometric and morphological near-IR data from the VVVX survey. Using the VVV-NIRGC, we analyse by statistical methods the most relevant features for galaxy identification. This catalogue was used to train a CNN with image data and an XGBoost model with both photometric and morphological data and then to generate a dataset of extragalactic candidates. This allows us to derive probability catalogues used to analyse the completeness and purity as a function of the configuration parameters and to explore the best combinations of the models. As a test case, we apply this methodology to the Northern disc region of the VVVX survey, obtaining 172,396 extragalatic candidates with probabilities of being galaxies. We analyse the performance of our methodology in the VVV disc, reaching an F1-score of 0.67, a 65 per cent purity and a 69 per cent completeness. We present the VVV-NIR Galaxy Catalogue: Northern part of the Galactic disc comprising 1,003 new galaxies, with probabilities greater than 0.6 for either model, with visual inspection and with only 2 previously identified galaxies. In the future, we intend to apply this methodology to other areas of the VVVX survey.Comment: 12 pages, 14 figures, accepted in MNRA

The CARMENES search for exoplanets around M dwarfs: Nine new double-line spectroscopic binary stars

Context. The CARMENES spectrograph is surveying ~300 M dwarf stars in search for exoplanets. Among the target stars, spectroscopic binary systems have been discovered, which can be used to measure fundamental properties of stars. Aims. Using spectroscopic observations, we determine the orbital and physical properties of nine new double-line spectroscopic binary systems by analysing their radial velocity curves. Methods. We use two-dimensional cross-correlation techniques to derive the radial velocities of the targets, which are then employed to determine the orbital properties. Photometric data from the literature are also analysed to search for possible eclipses and to measure stellar variability, which can yield rotation periods. Results. Out of the 342 stars selected for the CARMENES survey, 9 have been found to be double-line spectroscopic binaries, with periods ranging from 1.13 to ~8000 days and orbits with eccentricities up to 0.54. We provide empirical orbital properties and minimum masses for the sample of spectroscopic binaries. Absolute masses are also estimated from mass-luminosity calibrations, ranging between ~0.1 and ~0.6 Msol . Conclusions. These new binary systems increase the number of double-line M dwarf binary systems with known orbital parameters by 15%, and they have lower mass ratios on average.Comment: Accepted for publication in A&A. 17 pages, 4 figure

Association between combinations of genetic polymorphisms and epidemiopathogenic forms of bovine paratuberculosis

[EN] Control of major mycobacterial diseases affecting livestock is a challenging issue that requires different approaches. The use of genetic markers for improving resistance to Mycobacterium avium subsp. paratuberculosis infection in cattle has been explored as a promising population strategy We performed paratuberculosis epidemiopathogenic phenotypic and genotypic characterization involving 24 SNPs in six candidate genes (NOD2, CD209, SLC11A1, SP110, TLR2 and TLR4) on 502 slaughtered Friesian cows. In the current study, we investigate whether recently proposed paratuberculosis (PTB) epidemiopathogenic (EP) forms (apparently free-AF, latent-LAT and patent-PAT) could be associated with some combination of these 24 SNPs. Best EP form grouping was obtained using a combination of 5 SNPs in four genes (CD209: rs210748127; SLC11A1: rs110090506; SP110: rs136859213 and rs110480812; and TLR2: rs41830058). These groups were defined according to the level of infection progression risk to patent epidemiopathogenic forms and showed the following distributions: LOWIN (low) with 39 (8%) cases (94.9% AF/5.1% LAT/0% PAT); LATIN (low) with 17 (3%) cases (5.9% AF/94.1% LAT/0% PAT); AVERIN (average) with 413 (82%) cases (52.1% AF/38.5% LAT/9.4% PAT) and PATIN (patent) with 33 (7%) cases (36.4% AF/24.2% LAT/39.4% PAT). Age of slaughter was significantly higher for LATIN (88.3 months) compared to AVERIN (65.3 months; p = 0.0007) and PATIN (59.1 months; p = 0.0004), and for LOWIN (73.9 months) compared to PATIN (p = 0.0233), and nearly significant compared to AVERIN (p = 0.0572) These results suggest that some selected genetic polymorphisms have a potential use as markers of PTB EP forms and thus add a new tool for the control of this widespread infectionSIThis work was supported by the Ministry of Economy and Competitiveness (MINECO) (projects AGL2006-14315-C02 and RTA2014-00009), Basque Government (GV/EJ) (SAIOTEK program: SA-2010/00102), European Regional Development Fund (ERDF), and European Social Fund (ESF) is also gratefully acknowledged. Patricia V azquez was holder of a graduate fellowship award (FPI) (BES-2007-17170) from the Spanish MINEC

Detection of He I λ10830\lambda10830 \AA{} absorption on HD 189733 b with CARMENES high-resolution transmission spectroscopy

We present three transit observations of HD 189733 b obtained with the high-resolution spectrograph CARMENES at Calar Alto. A strong absorption signal is detected in the near-infrared He I triplet at 10830 \AA{} in all three transits. During mid-transit, the mean absorption level is $0.88\pm0.04$ % measured in a $\pm$10 km s$^{-1}$ range at a net blueshift of $-3.5\pm0.4$ km s$^{-1}$ (10829.84--10830.57 \AA{}). The absorption signal exhibits radial velocities of $+6.5\pm3.1$ km s$^{-1}$ and $-12.6\pm1.0$ km s$^{-1}$ during ingress and egress, respectively; measured in the planetary rest frame. We show that stellar activity related pseudo-signals interfere with the planetary atmospheric absorption signal. They could contribute as much as 80% of the observed signal and might also affect the radial velocity signature, but pseudo-signals are very unlikely to explain the entire signal. The observed line ratio between the two unresolved and the third line of the He I triplet is $2.8\pm0.2$, which strongly deviates from the value expected for an optically thin atmospheres. When interpreted in terms of absorption in the planetary atmosphere, this favors a compact helium atmosphere with an extent of only 0.2 planetary radii and a substantial column density on the order of $4\times 10^{12}$ cm$^{-2}$. The observed radial velocities can be understood either in terms of atmospheric circulation with equatorial superrotation or as a sign of an asymmetric atmospheric component of evaporating material. We detect no clear signature of ongoing evaporation, like pre- or post-transit absorption, which could indicate material beyond the planetary Roche lobe, or radial velocities in excess of the escape velocity. These findings do not contradict planetary evaporation, but only show that the detected helium absorption in HD 189733 b does not trace the atmospheric layers that show pronounced escape signatures.Comment: 13 pages, 12 figures, accepted for publication in A&

Aportaciones al conocimiento de la evolución paleoclimática y paleoambiental en la Península Ibérica durante los dos ultimos millones de años a partir del estudio de trasvertinos y espeleotemas

En este trabajo se contemplan los resultados principales del Proyecto" Reconstrucción Paleoclimática desde el Pleistoceno Medio a partir de análisis geocronológicos e isotópicos de travertinos españoles" (P. CEC FI2W-CT91-0075 " Paleoclimatological revision of climate evolution in the Western Mediterranean Region, Evaluation of altered scenarios) . Se seleccionaron cuatro áreas de depósitos travertínicos de carácter fluvial (Priego, Río Blanco), lacustre (Río Blanco, Banyoles) y aluvial (Tolox) así como una zona con depósitos espeleotémicos (Karst de la Cueva del Reguerillo). En ellas se obtuvieron datos sobre la evolución del paisaje y del clima, los travertinos y espeleotemas son indicadores de clima cálido s.l. que de forma abreviada son: O Mediante la geomorfología y dataciones (paleomagnetismo, U/Th, Resonancia de espín Resumen electrónico y racemización de aminoácidos), se determinó las historia fluvial de los travertinos de Priego y Río Blanco así como del Karst de la Cueva del Reguerillo donde, además, se dataron un paleosismo y fenómenos de neotectónica. La data más antigua obtenida mediante Resonancia de espín electrónico fue 950ka, mientras que mediante racemización de aminoácidos se dataron depósitos de más de 750ka. Mediante dataciones, sedimentología, análisis de isótopos estables y palinología se determinaron aspectos de la evolución climática de algunas áreas de la Península Ibérica. La correlación entre palinología e isotopía permitió la validación de algunos de los resultados. También se obtuvieron datos cualitativos sobre input hidraúlicos a los sistemas fluviales o kársticos

The CARMENES search for exoplanets around M dwarfs. Period search in Hα\alpha, Na I D, and Ca II IRT lines

We use spectra from CARMENES, the Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Echelle Spectrographs, to search for periods in chromospheric indices in 16 M0 to M2 dwarfs. We measure spectral indices in the H$\alpha$, the Ca II infrared triplet (IRT), and the Na I D lines to study which of these indices are best-suited to find rotation periods in these stars. Moreover, we test a number of different period-search algorithms, namely the string length method, the phase dispersion minimisation, the generalized Lomb-Scargle periodogram, and the Gaussian process regression with quasi-periodic kernel. We find periods in four stars using H$\alpha$ and in five stars using the Ca II IRT, two of which have not been found before. Our results show that both H$\alpha$ and the Ca II IRT lines are well suited for period searches, with the Ca II IRT index performing slightly better than H$\alpha$. Unfortunately, the Na I D lines are strongly affected by telluric airglow, and we could not find any rotation period using this index. Further, different definitions of the line indices have no major impact on the results. Comparing the different search methods, the string length method and the phase dispersion minimisation perform worst, while Gaussian process models produce the smallest numbers of false positives and non-detections.Comment: 14 pages + 17 pages appendix, 9+16 figures, accepted to A&