1,142 research outputs found

    Ionized gas outflows and global kinematics of low-z luminous star forming galaxies

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    We study the kinematic properties of the ambient ionized ISM and ionized gas outflows in a large and representative sample of local luminous and ultraluminous infrared galaxies (U/LIRGs) (58 systems, 75 galaxies), on the basis of integral field spectroscopy (IFS)-based high S/N integrated spectra at galactic and sub-galactic, i.e. star forming (SF) clumps, scales. Ambient ionized gas. The velocity dispersion of the ionized ISM in U/LIRGs ( ~ 70 kms-1) is larger than in lower luminosity local star forming galaxies ( ~ 25 kms-1). While for isolated disc LIRGs star formation appears to sustain turbulence, gravitational energy release associated to interactions and mergers plays an important role driving sigma in the U/LIRG range. We also find that the impact of an AGN in ULIRGs is strong, increasing sigma by a factor 1.5 on average. The observed weak dependency of sigma with SFR surface density for local U/LIRGs is in very good agreement with that measured in some high-z samples. Ionized outflows. The presence of ionized gas outflows in U/LIRGs seems universal based on the detection of a broad, usually blueshifted, Halpha line. AGNs in U/LIRGs are able to generate faster (x2) and more massive (x1.4) ionized gas outflows than pure starbursts. The derived ionized mass loading factors are in general below one, with only a few AGNs above this limit. Only a small fraction of the ionized material from low mass LIRGs (log(Mdyn/Msun) < 10.4) could reach the intergalactic medium, with more massive galaxies retaining the gas. The observed average outflow properties in U/LIRGs are similar to high-z galaxies of comparable SFR. In the bright SF clumps found in LIRGs, ionized gas outflows appear to be very common. For a given SFR surface density, outflows in LIRG clumps would be about one to two orders of magnitude less energetic than those launched by clumps in high-z SF galaxies.Comment: 36 pages, 20 figures, 6 tables. Accepted for publication in A&

    Divergence before the division : the colonial origins of separate development paths in Korea

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    This study revisits the question of what impact Japanese colonialism had on the long-term economic development of North and South Korea. Factor endowments, economic activity and economic performance are compared between the regions that later became parts of North and South Korea, respectively. The study finds that important elements of the economic history of the peninsula have not been sufficiently acknowledged in much of the influential literature that uses Korea as an illustration of theoretical claims of the root causes of development. In particular, the fact that the economic divergence of northern and southern regions could be traced back to different colonial treatments – especially after mid-1920s – has often been overlooked when analysing the divergent post-partition development trajectories. The study suggests, based on a sectoral similarities analysis, that the initial dissimilar economic performance of North and South can at least partially be found in differences in political economy and economic trajectories preceding the partition.Publisher PDFPeer reviewe

    Sleep Disorders in Multiple Sclerosis

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    Patients with multiple sclerosis (MS) have multiple causes of poor sleep and potential triggers may relate to MS-related symptoms, co-morbidities and adverse effects from medication. Sleep disorders may occur independently of demographic factors, gender and clinical condition. The real frequency of sleep disturbances in MS and their impact on the patients’ quality of life are unknown. The prevalence of sleep problems in the population with MS ranges between 47 and 62% and is more frequent in women, as well as having a higher risk of mortality. High psychological burden has been associated with poor sleep and with increased risk of co-morbid conditions such as heart disease, obesity, dyslipidemia and diabetes, which may have a profound impact on long-term health. The poor sleeping patients with MS were more likely to report fatigue and sleepiness. Insomnia is present in mood disorders, restless leg syndrome (RLS), pain, nocturia and obstructive sleep apnea (OSA), in patients with MS. All the symptoms are intermixed, and it is not possible to discern the precipitating factor or the perpetuating factor. Clinicians should routinely ask about sleep when forming a comprehensive care plan for patients with MS. Sleep specialty referrals should be considered for management of conditions that require polysomnography (PSG) diagnosis

    Outflow of hot and cold molecular gas from the obscured secondary nucleus of NGC3256: closing in on feedback physics

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    The nuclei of merging galaxies are often deeply buried in dense layers of gas and dust. In these regions, gas outflows driven by starburst and AGN activity are believed to play a crucial role in the evolution of these galaxies. However, to fully understand this process it is essential to resolve the morphology and kinematics of such outflows. Using near-IR integral-field spectroscopy obtained with VLT/SINFONI, we detect a kpc-scale structure of high-velocity molecular hydrogen (H2) gas associated with the deeply buried secondary nucleus of the IR-luminous merger NGC3256. We show that this structure is likely the hot component of a molecular outflow, which is detected also in the cold molecular gas by Sakamoto et al. This outflow, with a molecular gas mass of M(H2)~2x10^7 Msun, is among the first to be spatially resolved in both the hot H2 gas with VLT/SINFONI and the cold CO-emitting gas with ALMA. The hot and cold components share a similar morphology and kinematics, with a hot-to-cold molecular gas mass ratio of ~6x10^-5. The high (~100 pc) resolution at which we map the geometry and velocity structure of the hot outflow reveals a biconical morphology with opening angle ~40 deg and gas spread across a FWZI~1200 km/s. Because this collimated outflow is oriented close to the plane of the sky, the molecular gas may reach maximum intrinsic outflow velocities of ~1800 km/s, with an average mass outflow rate of at least ~20 Msun/yr. By modeling the line-ratios of various near-IR H2 transitions, we show that the H2 gas in the outflow is heated through shocks or X-rays to a temperature of ~1900K. The energy needed to drive the outflow is likely provided by a hidden Compton-thick AGN or by the nuclear starburst. We show that the global kinematics of the molecular outflow in NGC3256 mimic those of CO-outflows that have been observed at low spatial resolution in starburst- and active galaxies.Comment: Accepted in Astronomy and Astrophysics (accepted 29 Aug 2014 v.3, initial submission v.1 14 March 2014), 13 pages, 8 figure
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