Studi per la messa a punto di un sit geologico stratigrafico e geologico applicato-il sit delle aree carsiche

2008/2009L’obiettivo principale del lavoro è stato la creazione di un Geodatabase per raccogliere, in un ottica di tipo interdisciplinare, dati relativi agli aspetti geologici, geomorfologici ed idrogeologici delle aree carsiche che ricadono nel territorio della Regione Friuli Venezia Giulia, costruendo così un valido punto di partenza per diverse applicazioni che spaziano dall’ambito puramente scientifico a quello di gestione e salvaguardia di queste peculiari zone. Per la realizzazione di questo progetto è stato necessario un primo lavoro di raccolta dati, facendo riferimento sia a banche dati esistenti sia effettuando talvolta rilevamenti mirati sul territorio. In seguito i dati raccolti sono stati elaborati e standardizzati per consentire la creazione del Sistema Informativo Geografico. A questo scopo ci si è avvalsi delle potenzialità del software GIS ArcGIS 9.1 che ha consentito appunto di creare il Geodatabase. Tramite i dati raccolti e strutturati in livelli tematici è stato possibile ricavare il quadro completo relativo alla distribuzione dei fenomeni carsici nella regione Friuli Venezia Giulia. Successivamente, anche al fine di predisporre gli elementi per la creazione di un catasto delle aree carsiche della Regione Friuli Venezia Giulia è stato ricercato un metodo di classificazione e suddivisione delle aree carsiche riconosciute. In particolare è stata elaborata una metodologia di suddivisione che prevede l’individuazione di quattro livelli territoriali di approfondimento l’ultimo dei quali è rappresentato dalle Aree carsiche intese come unità omogenee dal punto di vista geomorfologico ed i cui confini rappresentano i limiti di un idrostruttura. La definizione dei confini delle aree è infatti avvenuta tenendo conto principalmente di fattori di ordine idrogeologico e quindi di ordine geomorfologico. Ai fini dell’individuazione dei confini delle aree carsiche sono in stati utilizzati tutti i livelli disponibili del GDB creato. Per definire le caratteristiche di ogni area si è fatto riferimento ai diversi livelli tematici del GIS e per implementare ulteriormente le informazioni ad esse afferenti sono stati creati per ognuna dei DEM a partire dalla CTRN. Per consentire una maggiore fruibilità dei dati contenuti nel Sistema Informativo Geografico sono stati gettati i presupposti per la creazione di un Catasto Aree Carsiche del Friuli Venezia Giulia. In particolare le informazioni relative ad ognuna delle Aree carsiche sono state sintetizzate e convogliate all’interno di schede catastali progettate e realizzate scegliendo una serie di campi standard che possano essere adattati a tutte le Aree.XX Ciclo197

Potential impact of a proposed railway tunnel on the karst environment: The example of Rosandra valley, Classical Karst region, Italy-Slovenia

Val Rosandra is a unique geomorphological environment located on the western side of the Classical Karst Plateau (NE Italy). This deep limestone gorge is crossed by a stream that is fed by a large basin located in Slovenia. Val Rosandra is the only example of a karst river valley withsurface hydrography in the Classical Karst Plateau. The torrent that crosses it digs a deep gully into the rock, richin rapids, swirl holes, small waterfalls, enclosed meanders and basins; here, the first seepage phenomena occur, and part of the water feeds the underground aquifer.Val Rosandra is characterised by a complex structural situation. The NE slope culminates in the structure of Mt. Stena, a limestone tectonic wedge between two faults, firmly rooted in the karst platform. Bothits external morphology and its caves are influenced by the structure, i.e. by the attitude of bedding planes, fault planes and master joints. Mt. Stena, in particular, hosts a comprehensive net of articulated and diversely shaped caves, basically organised on several levels. This network stretches over a total of 9,000 metres, bearing testimony to ancient geological and hydrogeological origins.The deepest areas of the system reacha suspended aquifer that is probably sustained by an overthrust and placed about 100 meters above the underground aquifer of the Rosandra torrent.A series of feasibility studies on the Trieste-Divača high-speed railway link concentrated on the potential interaction between the project and karst features. In line withthe project requirements, risk of voids intersection and water contamination were analyzed as Mt. Stena’s suspended aquifer partially feeds the Rosandra torrent, whichflows in a protected natural area. We therefore suggest that further investigations ought to be performed to integrate the existing knowledge on karst and on the hydrogeological aspects of the massif

Pegasus V -- a newly discovered ultra-faint dwarf galaxy on the outskirts of Andromeda

We report the discovery of an ultra-faint dwarf in the constellation of Pegasus. Pegasus~V (Peg~V) was initially identified in the public imaging data release of the DESI Legacy Imaging Surveys and confirmed with deep imaging from Gemini/GMOS-N. The colour-magnitude diagram shows a sparse red giant branch (RGB) population and a strong over-density of blue horizontal branch stars. We measure a distance to Peg~V of $D=692^{+33}_{-31}$~kpc, making it a distant satellite of Andromeda with $M_V=-6.3\pm0.2$ and a half-light radius of $r_{\rm half}=89\pm41$~pc. It is located $\sim260$~kpc from Andromeda in the outskirts of its halo. The RGB is well-fit by a metal-poor isochrone with [Fe/H]$=-3.2$, suggesting it is very metal poor. This, combined with its blue horizontal branch could imply that it is a reionisation fossil. This is the first detection of an ultra-faint dwarf outside the deep Pan-Andromeda Archaeological Survey area, and points to a rich, faint satellite population in the outskirts of our nearest neighbour.Comment: Submitted to MNRAS Letters. 6 pages, 4 figures. Comments welcom

K-band Properties of Well-Sampled Groups of Galaxies

We use a sample of 55 groups and 6 clusters of galaxies ranging in mass from 7 x 10^11 Msun to 1.5 x 10^15 Msun to examine the correlation of the Ks-band luminosity with mass discovered by Lin et al. (2003). We use the 2MASS catalog and published redshifts to construct complete magnitude limited redshift surveys of the groups. From these surveys we explore the IR photometric properties of groups members including their IR color distribution and luminosity function. Although we find no significant difference between the group Ks luminosity function and the general field, there is a difference between the color distribution of luminous group members and their counterparts (generally background) in the field. There is a significant population of luminous galaxies with H-Ks > 0.35 which are rarely, if ever, members of the groups in our sample. The most luminous galaxies which populate the groups have a very narrow range of IR color. Over the entire mass range covered by our sample, the Ks luminosity increases with mass as L ~ M^(0.64 +/- 0.06) implying that the mass-to-light ratio in the Ks-band increases with mass. The agreement between this result and earlier investigations of essentially non-overlapping sets of systems shows that this window in galaxy formation and evolution is insensitive to the selection of the systems and to the details of the mass and luminosity computations.Comment: 38 pages, 9 figures, 2 tables. Accepted for publication on Astronomical Journa

Pisces VII: Discovery of a possible satellite of Messier 33 in the DESI Legacy Imaging Surveys

We report deep imaging observations with DOLoRes@TNG of an ultra-faint dwarf satellite candidate of the Triangulum galaxy (M33) found by visual inspection of the public imaging data release of the DESI Legacy Imaging Surveys. Pisces VII/Triangulum (Tri) III is found at a projected distance of 72 kpc from M33, and using the tip of the red giant branch method we estimate a distance of D=1.0 +0.3,-0.2 Mpc, meaning the galaxy could either be an isolated ultra-faint or the second known satellite of M33. We estimate an absolute magnitude of M_V=-6.1+/-0.2 if Pisces VII/Tri II is at the distance of M33, or as bright as M_V=-6.8+/-0.2 if the galaxy is isolated. At the isolated distance, it has a physical half-light radius of r_h=131+/-61 pc consistent with similarly faint galaxies around the Milky Way. As the tip of the red giant branch is sparsely populated, constraining a precision distance is not possible, but if Pisces VII/Tri III can be confirmed as a true satellite of M33 it is a significant finding. With only one potential satellite detected around M33 previously (Andromeda XXII/Tri I), it lacks a significant satellite population in stark contrast to the similarly massive Large Magellanic Cloud. The detection of more satellites in the outskirts of M33 could help to better illuminate if this discrepancy between expectation and observations is due to a poor understanding of the galaxy formation process, or if it is due to the low luminosity and surface brightness of the M33 satellite population which has thus far fallen below the detection limits of previous surveys. If it is truly isolated, it would be the faintest known field dwarf detected to date.Comment: 10 pages, 9 figures, 2 tables, accepted for publication in MNRAS. This final version includes a moderate revision after the referee's comments and a correct titl

Puzzling large-scale polarization in the galaxy cluster Abell 523

Large-scale magnetic fields reveal themselves through diffuse synchrotron sources observed in galaxy clusters such as radio halos. Total intensity filaments of these sources have been observed in polarization as well, but only in three radio halos out of about one hundred currently known. In this paper we analyze new polarimetric Very Large Array data of the diffuse emission in the galaxy cluster Abell 523 in the frequency range 1-2 GHz. We find for the first time evidence of polarized emission on scales of ~ 2.5 Mpc. Total intensity emission is observed only in the central part of the source, likely due to observational limitations. To look for total intensity emission beyond the central region, we combine these data with single-dish observations from the Sardinia Radio Telescope and we compare them with multi-frequency total intensity observations obtained with different instruments, including the LOw Frequency ARray and the Murchison Widefield Array. By analysing the rotation measure properties of the system and utilizing numerical simulations, we infer that this polarized emission is associated with filaments of the radio halo located in the outskirts of the system, in the peripheral region closest to the observer.Comment: 14 pages, 12 figures, accepted for publication on MNRA

Spectro-polarimetric observations of the CIZA J2242.8+5301 northern radio relic: no evidence of high-frequency steepening

Observations of radio relics at very high frequency (>10 GHz) can help to understand how particles age and are (re-)accelerated in galaxy cluster outskirts and how magnetic fields are amplified in these environments. In this work, we present new single-dish 18.6 GHz Sardinia Radio Telescope and 14.25 GHz Effelsberg observations of the well known northern radio relic of CIZA J2242.8+5301. We detected the relic which shows a length of $\sim$1.8 Mpc and a flux density equal to $\rm S_{14.25\,GHz}=(9.5\pm3.9)\,mJy$ and $\rm S_{18.6\,GHz}=(7.67\pm0.90)\,mJy$ at 14.25 GHz and 18.6 GHz respectively. The resulting best-fit model of the relic spectrum from 145 MHz to 18.6 GHz is a power-law spectrum with spectral index $\alpha=1.12\pm0.03$: no evidence of steepening has been found in the new data presented in this work. For the first time, polarisation properties have been derived at 18.6 GHz, revealing an averaged polarisation fraction of $\sim40\%$ and a magnetic field aligned with the 'filaments' or 'sheets' of the relic.Comment: 10 pages, 8 figure

Characterizing K2 planet discoveries : a super-Earth transiting the bright K dwarf HIP 116454

We report the first planet discovery from the two-wheeled Kepler (K2) mission: HIP 116454 b. The host star HIP 116454 is a bright (V = 10.1, K = 8.0) K1 dwarf with high proper motion and a parallax-based distance of 55.2 ± 5.4 pc. Based on high-resolution optical spectroscopy, we find that the host star is metal-poor with [Fe/H] =–0.16 ± 0.08 and has a radius R = 0.716 ± 0.024 R ☉ and mass M = 0.775 ± 0.027 M ☉. The star was observed by the Kepler spacecraft during its Two-Wheeled Concept Engineering Test in 2014 February. During the 9 days of observations, K2 observed a single transit event. Using a new K2 photometric analysis technique, we are able to correct small telescope drifts and recover the observed transit at high confidence, corresponding to a planetary radius of pR = 2.53 ± 0.18 R ⊕. Radial velocity observations with the HARPS-N spectrograph reveal a 11.82 ± 1.33 M ⊕ planet in a 9.1 day orbit, consistent with the transit depth, duration, and ephemeris. Follow-up photometric measurements from the MOST satellite confirm the transit observed in the K2 photometry and provide a refined ephemeris, making HIP 116454 b amenable for future follow-up observations of this latest addition to the growing population of transiting super-Earths around nearby, bright stars.Publisher PDFPeer reviewe

Spectral study of the diffuse synchrotron source in the galaxy cluster Abell 523

The galaxy cluster Abell 523 (A523) hosts an extended diffuse synchrotron source historically classified as a radio halo. Its radio power at 1.4 GHz makes it one of the most significant outliers in the scaling relations between observables derived from multiwavelength observations of galaxy clusters: it has a morphology that is different and offset from the thermal gas, and it has polarized emission at 1.4 GHz typically difficult to observe for this class of sources. A magnetic field fluctuating on large spatial scales (similar to 1 Mpc) can explain these peculiarities but the formation mechanism for this source is not yet completely clear. To investigate its formation mechanism, we present new observations obtained with the LOw Frequency ARray at 120-168 MHz and the Jansky Very Large Array at 1-2 GHz, which allow us to study the spectral index distribution of this source. According to our data the source is observed to be more extended at 144 MHz than previously inferred at 1.4 GHz, with a total size of about 1.8 Mpc and a flux density S-144 MHz = (1.52 +/- 0.31) Jy. The spectral index distribution of the source is patchy with an average spectral index alpha similar to 1.2 between 144 MHz and 1.410 GHz, while an integrated spectral index alpha similar to 2.1 has been obtained between 1.410 and 1.782 GHz. A previously unseen patch of steep spectrum emission is clearly detected at 144 MHz in the south of the cluster. Overall, our findings suggest that we are observing an overlapping of different structures, powered by the turbulence associated with the primary and a possible secondary merger.Peer reviewe

Using HARPS-N to characterise the long-period planets in the PH-2 and Kepler-103 systems

We present confirmation of the planetary nature of PH-2b, as well as the first mass estimates for the two planets in the Kepler-103 system. PH-2b and Kepler-103c are both long-period and transiting, a sparsely-populated category of exoplanet. We use {\it Kepler} light-curve data to estimate a radius, and then use HARPS-N radial velocities to determine the semi-amplitude of the stellar reflex motion and, hence, the planet mass. For PH-2b we recover a 3.5-$\sigma$ mass estimate of $M_p = 109^{+30}_{-32}$ M$_\oplus$ and a radius of $R_p = 9.49\pm0.16$ R$_\oplus$. This means that PH-2b has a Saturn-like bulk density and is the only planet of this type with an orbital period $P > 200$ days that orbits a single star. We find that Kepler-103b has a mass of $M_{\text{p,b}} = 11.7^{+4.31}_{-4.72}$ M$_{\oplus}$ and Kepler-103c has a mass of $M_{\text{p,c}} = 58.5^{+11.2}_{-11.4}$ M$_{\oplus}$. These are 2.5$\sigma$ and 5$\sigma$ results, respectively. With radii of $R_{\text{p,b}} = 3.49^{+0.06}_{-0.05}$ R$_\oplus$, and $R_{\text{p,c}} = 5.45^{+0.18}_{-0.17}$ R$_\oplus$, these results suggest that Kepler-103b has a Neptune-like density, while Kepler-103c is one of the highest density planets with a period $P > 100$ days. By providing high-precision estimates for the masses of the long-period, intermediate-mass planets PH-2b and Kepler-103c, we increase the sample of long-period planets with known masses and radii, which will improve our understanding of the mass-radius relation across the full range of exoplanet masses and radii.The HARPS-N project has been funded by the Prodex Program of the Swiss Space Office (SSO), the Harvard University Origins of Life Initiative (HUOLI), the Scottish Universities Physics Alliance (SUPA), the University of Geneva, the Smithsonian Astrophysical Observatory (SAO), and the Italian National Astrophysical Institute (INAF), the University of St Andrews, Queen’s University Belfast, and the University of Edinburgh. AM acknowledges support from Senior Kavli Institute Fellowships at the University of Cambridge. ACC acknowledges support from the Science & Technology Facilities Council (STFC) consolidated grant number ST/R000824/1. AV’s and RDH’s work was performed under contract with the California Institute of Technology/Jet Propulsion Laboratory funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute. LM acknowledges support from PLATO ASI-INAF agreement n.2015-019-R.1-2018 This publication was made possible through the support of a grant from the John Templeton Foundation. The opinions expressed in this publication are those of the authors and do not necessarily reflect the views of the John Templeton Foundation. This material is partly based upon work supported by the National Aeronautics and Space Administration under grants No. NNX15AC90G and NNX17AB59G issued through the Exoplanets Research Program. Some of this work has been carried out in the frame of the National Centre for Competence in Research ‘PlanetS’ supported by the Swiss National Science Foundation (SNSF)