114 research outputs found

    DOES THE FUNDING OF THE DEFENCE SECTOR DEPEND ON ECONOMIC FACTORS IN THE LONG RUN? THE CASES OF ESTONIA, LATVIA, AND LITHUANIA

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    The purpose of this publication is to study the dependence of defence funding on economic factors, namely the prosperity of the country, economic growth, the budget deficit, gross government debt, and inflation rate. The investigation uses secondary data obtained from the Eurostat database and covers the period from 1997 to 2021. The author analyses three Baltic countries such as Estonia, Latvia, and Lithuania, to ascertain which economic factors have a statistically significant effect on defence sector funding. For this purpose, the author applies correlation analysis and automatic linear modelling (ALM). The findings of the investigation showed differences and similarities between the countries under consideration. In the case of Estonia, defence funding is significantly affected by the prosperity of the country, which is expressed in real GDP per capita, and gross government debt. These economic factors explain 92.6 per cent of defence funding. The cases of Latvia and Lithuania are very similar in terms of the influence of economic factors on defence spending. In these countries, the tendencies of real GDP per capita significantly effect on defence funding. This influence is slightly different and amounts to 76.2 and 78.4 per cent, for Latvia and Lithuania, respectively. The insights of the research can be useful to the governments of these nations when making decisions about defence funding aimed at ensuring security in the Baltic region

    Military and demographic inter-linkages in the context of the Lithuanian sustainability

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    This paper aims at investigating military and demographic inter-linkages in the context of the Lithuanian sustainability. The investigation combines three important economic aspects such as demographic, military and sustainable development. The authors have revealed that demographic trends should be seen as a necessary conditions for ensuring the functioning of the military sector contributes to public security and sustainable development in general. Correlation and stepwise regression analysis, also Monte Carlo forecasting method have been applied for this purpose. Research results have revealed statistically significant interrelationship between military personnel as a share of total labour force and population growth rate, population median age, total fertility rate as well as birth rate. Moreover, Monte Carlo forecasting method allowed revealing for the next 10 years a steady slight increase in armed forces personnel, stable population growth rates, a rapid aging process and a slight decline of total fertility rate. Military and demographic estimations and future projections allow government to incorporate information into planning and sustainable development policy. The insights from this research may contribute to implementing the goals of sustainable development related to eradication of poverty, inequality, social exclusion, improvement in education, well-being and employment and tackling climate change

    An ALMA survey of the SCUBA-2 Cosmology Legacy Survey UKIDSS/UDS field: halo masses for submillimetre galaxies

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    We present an analysis of the spatial clustering of a large sample of high-resolution, interferometically identified, submillimetre galaxies (SMGs). We measure the projected cross-correlation function of ∼350 SMGs in the UKIDSS Ultra Deep-Survey Field across a redshift range of z = 1.5–3 utilizing a method that incorporates the uncertainties in the redshift measurements for both the SMGs and cross-correlated galaxies through sampling their full probability distribution functions. By measuring the absolute linear bias of the SMGs, we derive halo masses of log10(Mhalo[h−1M⊙]) ∼ 12.8 with no evidence of evolution in the halo masses with redshift, contrary to some previous work. From considering models of halo mass growth rates, we predict that the SMGs will reside in haloes of mass log10(Mhalo[h−1M⊙]) ∼ 13.2 at z = 0, consistent with the expectation that the majority of z = 1.5–3 SMGs will evolve into present-day spheroidal galaxies. Finally, comparing to models of stellar-to-halo mass ratios, we show that SMGs may correspond to systems that are maximally efficient at converting their gas reservoirs into stars. We compare them to a simple model for gas cooling in haloes that suggests that the unique properties of the SMG population, including their high levels of star formation and their redshift distribution, are a result of the SMGs being the most massive galaxies that are still able to accrete cool gas from their surrounding intragalactic medium

    KURVS: The outer rotation curve shapes and dark matter fractions of z1.5z \sim 1.5 star-forming galaxies

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    We present first results from the KMOS Ultra-deep Rotation Velocity Survey (KURVS), aimed at studying the outer rotation curves shape and dark matter content of 22 star-forming galaxies at z1.5z\sim1.5. These galaxies represent `typical' star-forming discs at z1.5z \sim 1.5, being located within the star-forming main sequence and stellar mass-size relation with stellar masses 9.59.5\leqslantlog(M/M)11.5(M_{\star}/\mathrm{M_{\odot}})\leqslant11.5. We extract individual rotation curves out to 4 times the effective radius, on average, or 1015\sim 10-15 kpc. Most rotation curves are flat or rising between three- and six-disc scale radii. Only three objects with dispersion-dominated dynamics (vrot/σ00.2v_{\rm rot}/\sigma_0\sim0.2) have declining outer rotation curves at more than 5σ\sigma significance. After accounting for seeing and pressure support, the nine rotation-dominated discs with vrot/σ01.5v_{\rm rot}/\sigma_0\geqslant1.5 have average dark matter fractions of 50±20%50 \pm 20\% at the effective radius, similar to local discs. Together with previous observations of star-forming galaxies at cosmic noon, our measurements suggest a trend of declining dark matter fraction with increasing stellar mass and stellar mass surface density at the effective radius. Simulated EAGLE galaxies are in quantitative agreement with observations up to log(MReff2/Mkpc2)9.2(M_{\star}R_{\rm eff}^{-2}/\mathrm{M_{\odot}kpc^{-2}}) \sim 9.2, and over-predict the dark matter fraction of galaxies with higher mass surface densities by a factor of 3\sim 3. We conclude that the dynamics of typical rotationally-supported discs at z1.5z \sim 1.5 is dominated by dark matter from effective radius scales, in broad agreement with cosmological models. The tension with observations at high stellar mass surface density suggests that the prescriptions for baryonic processes occurring in the most massive galaxies (such as bulge growth and quenching) need to be reassessed.Comment: 23 pages, 9 figures. Resubmitted to MNRAS after addressing the referee's comments. Abstract slightly modified to compile with the arXiv formattin

    An ALMA survey of the S2CLS UDS field: optically invisible submillimetre galaxies

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    We analyse a robust sample of 30 near-infrared-faint (KAB > 25.3, 5σ) submillimetre galaxies (SMGs) selected from a 0.96 deg2 field to investigate their properties and the cause of their faintness in optical/near-infrared wavebands. Our analysis exploits precise identifications based on Atacama Large Millimeter Array (ALMA) 870-μm continuum imaging, combined with very deep near-infrared imaging from the UKIDSS Ultra Deep Survey. We estimate that SMGs with KAB > 25.3 mag represent 15 ± 2 per cent of the total population brighter than S870 = 3.6 mJy, with a potential surface density of ∼450 deg−2 above S870 ≥ 1 mJy. As such, they pose a source of contamination in surveys for both high-redshift ‘quiescent’ galaxies and very high redshift Lyman-break galaxies. We show that these K-faint SMGs represent the tail of the broader submillimetre population, with comparable dust and stellar masses to KAB ≤ 25.3 mag SMGs, but lying at significantly higher redshifts (z = 3.44 ± 0.06 versus z = 2.36 ± 0.11) and having higher dust attenuation (AV = 5.2 ± 0.3 versus AV = 2.9 ± 0.1). We investigate the origin of the strong dust attenuation and find indications that these K-faint galaxies have smaller dust continuum sizes than the KAB ≤ 25.3 mag galaxies, as measured by ALMA, which suggests their high attenuation is related to their compact sizes. We identify a correlation of dust attenuation with star formation rate surface density (SFR), with the K-faint SMGs representing the higher SFR and highest AV galaxies. The concentrated, intense star formation activity in these systems is likely to be associated with the formation of spheroids in compact galaxies at high redshifts, but as a result of their high obscuration these galaxies are completely missed in ultraviolet, optical, and even near-infrared surveys

    KAOSS: turbulent, but disc-like kinematics in dust-obscured star-forming galaxies at zz\sim1.3-2.6

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    We present spatially resolved kinematics of 31 ALMA-identified dust-obscured star-forming galaxies (DSFGs) at zz\sim1.3-2.6, as traced by Hα\alpha emission using VLT/KMOS near-infrared integral field spectroscopy from our on-going Large Programme ''KMOS-ALMA Observations of Submillimetre Sources'' (KAOSS). We derive Hα\alpha rotation curves and velocity dispersion profiles for the DSFGs. Of the 31 sources with bright, spatially extended Hα\alpha emission, 25 display rotation curves that are well fit by a Freeman disc model, enabling us to measure a median inclination-corrected velocity at 2.2RdR_{\rm d} of vrotv_{\rm rot} = 190 ±\pm 30 kms1^{-1} and a median intrinsic velocity dispersion of σ0\sigma_0 = 87 ±\pm 6 kms1^{-1} for these disc-like\textit{disc-like} sources. By comparison with less actively star-forming galaxies, KAOSS DSFGs are both faster rotating and more turbulent, but have similar vrot/σ0v_{\rm rot}/\sigma_0 ratios, median 2.4 ±\pm 0.5. We suggest that vrot/σ0v_{\rm rot}/\sigma_0 alone is insufficient to describe the kinematics of DSFGs, which are not kinematically ''cold'' discs, and that the individual components vrotv_{\rm rot} and σ0\sigma_0 indicate that they are in fact turbulent, but rotationally supported systems in \sim50 per cent of cases. This turbulence may be driven by star formation or mergers/interactions. We estimate the normalisation of the stellar Tully-Fisher relation (sTFR) for the disc-like DSFGs and compare it with local studies, finding no evolution at fixed slope between zz\sim2 and zz\sim0. Finally, we use kinematic estimates of DSFG halo masses to investigate the stellar-to-halo mass relation, finding our sources to be consistent with shock heating and strong feedback which likely drives the declining stellar content in the most massive halos.Comment: 20 pages, 12 figures, submitted to MNRAS, updated author lis

    Tracing the evolution of dust-obscured activity using sub-millimetre galaxy populations from STUDIES and AS2UDS

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    We analyse the physical properties of 121 SNR ≥ 5 sub-millimetre galaxies (SMGs) from the STUDIES 450 μm survey. We model their UV-to-radio spectral energy distributions using MAGPHYS+photo-z and compare the results to similar modelling of 850 μm-selected SMG sample from AS2UDS, to understand the fundamental physical differences between the two populations at the observed depths. The redshift distribution of the 450-μm sample has a median of z = 1.85 ± 0.12 and can be described by strong evolution of the far-infrared luminosity function. The fainter 450-μm sample has ∼14 times higher space density than the brighter 850-μm sample at z ≲ 2, and a comparable space density at z = 2–3, before rapidly declining, suggesting LIRGs are the main obscured population at z ∼ 1–2, while ULIRGs dominate at higher redshifts. We construct rest-frame ∼180-μm-selected and dust-mass-matched samples at z = 1–2 and z = 3–4 from the 450 and 850-μm samples, respectively, to probe the evolution of a uniform sample of galaxies spanning the cosmic noon era. Using far-infrared luminosity, dust masses, and an optically thick dust model, we suggest that higher redshift sources have higher dust densities due to inferred dust continuum sizes which are roughly half of those for the lower redshift population at a given dust mass, leading to higher dust attenuation. We track the evolution in the cosmic dust mass density and suggest that the dust content of galaxies is governed by a combination of both the variation of gas content and dust destruction time-scale

    An ALMA Survey of the SCUBA-2 Cosmology Legacy Survey UKIDSS/UDS Field: The Far-infrared/Radio Correlation for High-redshift Dusty Star-forming Galaxies

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    We study the radio properties of 706 submillimeter galaxies (SMGs) selected at 870 μm with the Atacama Large Millimeter Array from the SCUBA-2 Cosmology Legacy Survey map of the Ultra Deep Survey field. We detect 273 SMGs at >4σ in deep Karl G. Jansky Very Large Array 1.4 GHz observations, of which a subset of 45 SMGs are additionally detected in 610 MHz Giant Metre-Wave Radio Telescope imaging. We quantify the far-infrared/radio correlation (FIRRC) through parameter q IR, defined as the logarithmic ratio of the far-infrared and radio luminosity, and include the radio-undetected SMGs through a stacking analysis. We determine a median q IR = 2.20 ± 0.03 for the full sample, independent of redshift, which places these z ~ 2.5 dusty star-forming galaxies 0.44 ± 0.04 dex below the local correlation for both normal star-forming galaxies and local ultra-luminous infrared galaxies (ULIRGs). Both the lack of redshift evolution and the offset from the local correlation are likely the result of the different physical conditions in high-redshift starburst galaxies, compared to local star-forming sources. We explain the offset through a combination of strong magnetic fields (B gsim 0.2 mG), high interstellar medium (ISM) densities and additional radio emission generated by secondary cosmic rays. While local ULIRGs are likely to have similar magnetic field strengths, we find that their compactness, in combination with a higher ISM density compared to SMGs, naturally explains why local and high-redshift dusty star-forming galaxies follow a different FIRRC. Overall, our findings paint SMGs as a homogeneous population of galaxies, as illustrated by their tight and nonevolving far-infrared/radio correlation

    An ALMA/NOEMA survey of the molecular gas properties of high-redshift star-forming galaxies

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    We have used ALMA and NOEMA to study the molecular gas reservoirs in 61 ALMA-identified submillimetre galaxies (SMGs) in the COSMOS, UDS, and ECDFS fields. We detect 12CO (⁠Jup= 2–5) emission lines in 50 sources, and [C I](3P1 − 3P0) emission in eight, at z= 1.2–4.8 and with a median redshift of 2.9 ± 0.2. By supplementing our data with literature sources, we construct a statistical CO spectral line energy distribution and find that the 12CO line luminosities in SMGs peak at Jup ∼ 6, consistent with similar studies. We also test the correlations of the CO, [C I], and dust as tracers of the gas mass, finding the three to correlate well, although the CO and dust mass as estimated from the 3-mm continuum are preferable. We estimate that SMGs lie mostly on or just above the star-forming main sequence, with a median gas depletion timescale, tdep = Mgas/SFR, of 210 ± 40 Myr for our sample. Additionally, tdep declines with redshift across z ∼ 1–5, while the molecular gas fraction, μgas = Mgas/M*, increases across the same redshift range. Finally, we demonstrate that the distribution of total baryonic mass and dynamical line width, Mbaryon–σ, for our SMGs is consistent with that followed by early-type galaxies in the Coma cluster, providing strong support to the suggestion that SMGs are progenitors of massive local spheroidal galaxies. On the basis of this, we suggest that the SMG populations above and below an 870-μm flux limit of S870 ∼ 5 mJy may correspond to the division between slow and fast rotators seen in local early-type galaxies

    An ALMA survey of the SCUBA-2 CLS UDS field: physical properties of 707 sub-millimetre galaxies

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    We analyse the physical properties of a large, homogeneously selected sample of ALMA-located sub-millimetre galaxies (SMGs). This survey, AS2UDS, identified 707 SMGs across the ∼1 deg2 field, including ∼17 per cent, which are undetected at K ≳ 25.7 mag. We interpret their ultraviolet-to-radio data using magphys and determine a median redshift of z = 2.61 +- 0.08 (1σ range of z = 1.8-3.4) with just ∼6 per cent at z > 4. Our survey provides a sample of massive dusty galaxies at z ≳ 1, with median dust and stellar masses of Md = (6.8 +- 0.3) x 108 M⊙ (thus, gas masses of ∼1011 M⊙) and M* = (1.26 +- 0.05) x 1011 M⊙. We find no evolution in dust temperature at a constant far-infrared luminosity across z ∼ 1.5-4. The gas mass function of our sample increases to z ∼ 2-3 and then declines at z > 3. The space density and masses of SMGs suggest that almost all galaxies with M* ≳ 3 x 1011 M⊙ have passed through an SMG-like phase. The redshift distribution is well fit by a model combining evolution of the gas fraction in haloes with the growth of halo mass past a critical threshold of Mh ∼ 6 x 1012 M⊙, thus SMGs may represent the highly efficient collapse of gas-rich massive haloes. We show that SMGs are broadly consistent with simple homologous systems in the far-infrared, consistent with a centrally illuminated starburst. Our study provides strong support for an evolutionary link between the active, gas-rich SMG population at z > 1 and the formation of massive, bulge-dominated galaxies across the history of the Universe.The Durham co-authors acknowledge support from STFC (ST/P000541/1). The authors thank John Helly and Lydia Heck for help with HPC. The ALMA data used in this paper were obtained under programs ADS/JAO.ALMA#2012.1.00090.S, #2015.1.01528.S, and #2016.1.00434.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada) and NSC and ASIAA (Taiwan), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ. This work used the DiRAC@Durham facility managed by the Institute for Computational Cosmology on behalf of the STFC DiRAC HPC Facility (www.dirac.ac.uk). The equipment was funded by BEIS capital funding via STFC capital grants ST/K00042X/1, ST/P002293/1, ST/R002371/1, and ST/S002502/1, Durham University and STFC operations grant ST/R000832/1. DiRAC is part of the National e-Infrastructure. We extend our gratitude to the staff at UKIRT for their tireless efforts in ensuring the success of the UKIDSS UDS project. EdC gratefully acknowledges the Australian Research Council as the recipient of a Future Fellowship (project FT150100079). JLW acknowledges support from an STFC Ernest Rutherford Fellowship (ST/P004784/1 and ST/P004784/2
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