1,044 research outputs found

    Climate Change and Tourism in Tuscany, Italy. What if heat becomes unbearable?

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    This paper investigates the empirical magnitude of climate conditions on tourist flows in Tuscany, exploring the use of a fine spatial scale analysis. In fact, we explore the use of an 8-year panel dataset of Tuscany’s 254 municipalities, examining how tourist inflows respond to variation in local weather conditions. In particular, as the area enjoys a fairly mild Mediterranean climate, our analysis focused on temperature extremes at key times of the tourist season, i.e., on maximum summer temperature and minimum winter temperature. Separate analyses are conducted for domestic and international tourists, so as to test the differences in the preferences among these distinct groups (or types of demand). Estimation results show the impact of climate change on tourist flows appears to vary significantly among destinations depending on the kind of attractions they offer, and those areas that host the main artistic and historical sights, affecting predominantly the domestic rather than the international tourists.Domestic Tourists, International Tourists, Municipalities, Maximum And Minimum Daily Temperature, Dynamic Model, Temperature Demand Elasticity, GMM

    Integrated phylogenomic and fossil evidence of stick and leaf insects (Phasmatodea) reveal a Permian-Triassic co-origination with insectivores

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    Stick and leaf insects (Phasmatodea) are a distinctive insect order whose members are characterised by mimicking various plant tissues such as twigs, foliage, and bark. Unfortunately, the phylogenetic relationships among phasmatodean subfamilies and the timescale of their evolution remain uncertain. Recent molecular clock analyses have suggested a Cretaceous-Palaeogene origin of crown Phasmatodea and a subsequent Cenozoic radiation, contrasting with fossil evidence. Here we analysed transcriptomic data from a broad diversity of phasmatodeans and, combined with the assembly of a new suite of fossil calibrations, we elucidate the evolutionary history of stick and leaf insects. Our results differ from recent studies in the position of the leaf insects (Phylliinae), which are recovered as sister to a clade comprising Clitumninae, Lancerocercata, Lonchodinae, Necrosciinae, and Xenophasmina. We recover a Permian to Triassic origin of crown Phasmatodea coinciding with the radiation of early insectivorous parareptiles, amphibians, and synapsids. Aschiphasmatinae and Neophasmatodea diverged in the Jurassic–Early Cretaceous. A second spur in origination occurred in the Late Cretaceous, coinciding with the Cretaceous Terrestrial Revolution, and was likely driven by visual predators such as stem birds (Enantiornithes) and the radiation of angiosperms

    Fleas are parasitic scorpionflies

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    Tihelka, Erik, Giacomelli, Mattia, Huang, Di-Ying, Pisani, Davide, Donoghue, Philip C. J., Cai, Chen-Yang (2020): Fleas are parasitic scorpionflies. Palaeoentomology 3 (6): 641-653, DOI: 10.11646/palaeoentomology.3.6.1

    Origins Space Telescope: predictions for far-IR spectroscopic surveys

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    We illustrate the extraordinary potential of the (far-IR) Origins Survey Spectrometer (OSS) on board the Origins Space Telescope (OST) to address a variety of open issues on the co-evolution of galaxies and AGNs. We present predictions for blind surveys, each of 1000 h, with different mapped areas (a shallow survey covering an area of 10 deg2^{2} and a deep survey of 1 deg2^{2}) and two different concepts of the OST/OSS: with a 5.9 m telescope (Concept 2, our reference configuration) and with a 9.1 m telescope (Concept 1, previous configuration). In 1000 h, surveys with the reference concept will detect from 1.9×106\sim 1.9 \times 10^{6} to 8.7×106\sim 8.7 \times 10^{6} lines from 4.8×105\sim 4.8 \times 10^{5}-2.7×1062.7 \times 10^{6} star-forming galaxies and from 1.4×104\sim 1.4 \times 10^{4} to 3.8×104\sim 3.8 \times 10^{4} lines from 1.3×104\sim 1.3 \times 10^{4}-3.5×1043.5 \times 10^{4} AGNs. The shallow survey will detect substantially more sources than the deep one; the advantage of the latter in pushing detections to lower luminosities/higher redshifts turns out to be quite limited. The OST/OSS will reach, in the same observing time, line fluxes more than one order of magnitude fainter than the SPICA/SMI and will cover a much broader redshift range. In particular it will detect tens of thousands of galaxies at z5z \geq 5, beyond the reach of that instrument. The polycyclic aromatic hydrocarbons lines are potentially bright enough to allow the detection of hundreds of thousands of star-forming galaxies up to z8.5z \sim 8.5, i.e. all the way through the re-ionization epoch. The proposed surveys will allow us to explore the galaxy-AGN co-evolution up to z5.56z\sim 5.5-6 with very good statistics. OST Concept 1 does not offer significant advantages for the scientific goals presented here.Comment: 24 pages, 20 figures, 2 tables, accepted for publication in PAS

    Interpreting the statistical properties of High- z extragalactic sources detected by the South Pole Telescope Survey

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    Abstract: The results of the recently published spectroscopically complete survey of dusty star-forming galaxies detected by the South Pole Telescope over 2500 deg2 proved to be challenging for galaxy formation models that generally underpredict the observed abundance of high-z galaxies. In this paper we interpret these results in the light of a physically grounded model for the evolution of spheroidal galaxies. The model accurately reproduces the measured redshift distribution of galaxies without any adjustment of the parameters. The data do not support the indications of an excess of z > 4 dusty galaxies reported by some analyses of Herschel surveys

    Euclid view of the dusty star-forming galaxies at ≳ detected in wide area submillimetre surveys

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    We investigate the constraints provided by the Euclid space observatory on the physical properties of dusty star-forming galaxies (DSFGs) at detected in wide area submillimetre surveys with Herschel. We adopt a physical model for the high-z progenitors of spheroidal galaxies, which form the bulk of DSFGs at ⁠. We improve the model by combining the output of the equations of the model with a formalism for the spectral energy distribution (SED). After optimizing the SED parameters to reproduce the measured infrared luminosity function and number counts of DFSGs, we simulated a sample of DSFGs over 100  and then applied a detection limit of mJy at 250  m. We estimated the redshifts from the Euclid data and then fitted the Euclid+Herschel photometry with the code CIGALE to extract the physical parameters. We found that 100 per cent of the Herschel galaxies are detected in all 4 Euclid bands above ⁠. For 87 per cent of these sources the accuracy on is better than 15 per cent. The sample comprises mostly massive, i.e. ⁠, highly star forming, i.e. ⁠, dusty, i.e. ⁠, galaxies. The measured stellar masses have a dispersion of 0.19 dex around the true value, thus showing that Euclid will provide reliable stellar mass estimates for the majority of the bright DSFGs at detected by Herschel. We also explored the effect of complementing the Euclid photometry with that from the Vera C. Rubin Observatory/LSST

    Constraining νΛ\nu \LambdaCDM with density-split clustering

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    The dependence of galaxy clustering on local density provides an effective method for extracting non-Gaussian information from galaxy surveys. The two-point correlation function (2PCF) provides a complete statistical description of a Gaussian density field. However, the late-time density field becomes non-Gaussian due to non-linear gravitational evolution and higher-order summary statistics are required to capture all of its cosmological information. Using a Fisher formalism based on halo catalogues from the Quijote simulations, we explore the possibility of retrieving this information using the density-split clustering (DS) method, which combines clustering statistics from regions of different environmental density. We show that DS provides more precise constraints on the parameters of the νΛ\nu \LambdaCDM model compared to the 2PCF, and we provide suggestions for where the extra information may come from. DS improves the constraints on the sum of neutrino masses by a factor of 88 and by factors of 5, 3, 4, 6, and 6 for Ωm\Omega_m, Ωb\Omega_b, hh, nsn_s, and σ8\sigma_8, respectively. We compare DS statistics when the local density environment is estimated from the real or redshift-space positions of haloes. The inclusion of DS autocorrelation functions, in addition to the cross-correlation functions between DS environments and haloes, recovers most of the information that is lost when using the redshift-space halo positions to estimate the environment. We discuss the possibility of constructing simulation-based methods to model DS clustering statistics in different scenarios.Comment: Submitted to MNRAS. Source code for all figures in the paper is provided in the caption

    Does the evolution of the radio luminosity function of star-forming galaxies match that of the star-formation rate function?

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    The assessment of the relationship between radio continuum luminosity and star formation rate (SFR) is of crucial importance to make reliable predictions for the forthcoming ultra-deep radio surveys and to allow a full exploitation of their results to measure the cosmic star formation history. We have addressed this issue by matching recent accurate determinations of the SFR function up to high redshifts with literature estimates of the 1.4 GHz luminosity functions of star forming galaxies (SFGs). This was done considering two options, proposed in the literature, for the relationship between the synchrotron emission (L_\rm synch), that dominates at 1.4 GHz, and the SFR: a linear relation with a decline of the L_\rm synch/SFR ratio at low luminosities or a mildly non-linear relation at all luminosities. In both cases we get good agreement with the observed radio luminosity functions but, in the non-linear case, the deviation from linearity must be small. The luminosity function data are consistent with a moderate increase of the L_\rm synch/SFR ratio with increasing redshift, indicated by other data sets, although a constant ratio cannot be ruled out. A stronger indication of such increase is provided by recent deep 1.4 GHz counts, down to μ\muJy levels. This is in contradiction with models predicting a decrease of that ratio due to inverse Compton cooling of relativistic electrons at high redshifts. Synchrotron losses appear to dominate up to z5z\simeq 5. We have also updated the Massardi et al. (2010) evolutionary model for radio loud AGNs. Copyright The Authors 201

    Understanding galaxy formation and evolution through an all-sky submillimetre spectroscopic survey

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    We illustrate the extraordinary discovery potential for extragalactic astrophysics of a far-infrared/submillimetre (far-IR/submm) all-sky spectroscopic survey with a 3-m-class space telescope. Spectroscopy provides a three-dimensional view of the Universe and allows us to take full advantage of the sensitivity of present-day instrumentation, close to fundamental limits, overcoming the spatial confusion that affects broadband far-IR/submm surveys. A space telescope of the 3-m class (which has already been described in recent papers) will detect emission lines powered by star formation in galaxies out to . It will specifically provide measurements of spectroscopic redshifts, star-formation rates (SFRs), dust masses, and metal content for millions of galaxies at the peak epoch of cosmic star formation and of hundreds of them at the epoch of reionisation. Many of these star-forming galaxies will be strongly lensed; the brightness amplification and stretching of their sizes will make it possible to investigate (by means of follow-up observations with high-resolution instruments like ALMA, JWST, and SKA) their internal structure and dynamics on the scales of giant molecular clouds (40–100 pc). This will provide direct information on the physics driving the evolution of star-forming galaxies. Furthermore, the arcmin resolution of the telescope at submm wavelengths is ideal for detecting the cores of galaxy proto-clusters, out to the epoch of reionisation. Due to the integrated emission of member galaxies, such objects (as well as strongly lensed sources) will dominate at the highest apparent far-IR luminosities. Tens of millions of these galaxy-clusters-in-formation will be detected at –3, with a tail extending out to , and thousands of detections at . Their study will allow us to track the growth of the most massive halos well beyond what is possible with classical cluster surveys (mostly limited to –2), tracing the history of star formation in dense environments and teaching us how star formation and galaxy-cluster formation are related across all epochs. The obscured cosmic SFR density of the Universe will thereby be constrained. Such a survey will overcome the current lack of spectroscopic redshifts of dusty star-forming galaxies and galaxy proto-clusters, representing a quantum leap in far-IR/submm extragalactic astrophysics
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