jets and outflows

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Prevalence of radio jets associated with galactic outflows and feedback from quasars

Prevalence of radio jets associated with galactic outflows and feedback from quasars

An outflow driven by a quasar wind may produce loosely collimated radio structures on large scales due to the galactic disc collimating the outflow (Alexandroff et al. 2016). How- ever, the shocked wind scenario described above does not seem sufficient to explain the highly collimated radio struc- tures seen in our high-resolution radio images (e.g., partic- ularly see J1000 + 1242 and J1010 + 1413 in Fig. 5). Further- more, for J0958 + 1439, the radio structure appears to be di- rected into the disc (based on the SDSS morphology and [O iii ] kinematics; see Fig. 2 and Fig. 10) which also dis- favours the wind scenario, but be consistent with randomly oriented radio jets (e.g., Gallimore et al. 2006; Kharb et al. 2006). Unfortunately, it is challenging to identify the galaxy major axes based on the available imaging for most of our sources (see Fig. 2) and our optical IFS data of the targets are not deep enough to model the orientation of the stel- lar discs (Kang & Woo 2018). Another alternative to asses the relative orientations would be to identify a molecular galactic disc in these systems using resolved CO observa- tions (Thomson+in prep; Sun et al. 2014).

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Kiloparsec-scale outflows are prevalent among luminous AGN: outflows and feedback in the context of the overall AGN population

Kiloparsec-scale outflows are prevalent among luminous AGN: outflows and feedback in the context of the overall AGN population

where radio jets, launched by AGN, control the level of cooling of the hot gas in the most massive haloes (see Bower, Benson & Crain 2012; Harrison 2013, for a discussion on the two modes). While there is little doubt that star formation processes (e.g. stellar winds and supernovae) drive galaxy-wide outflows (e.g. Heckman, Armus & Miley 1990; Lehnert & Heckman 1996; Swinbank et al. 2009; Genzel et al. 2011; Newman et al. 2012; Bradshaw et al. 2013; see review in Veilleux, Cecil & Bland-Hawthorn 2005) and are an in- tegral part of galaxy evolution (e.g. Dalla Vecchia & Schaye 2008; Hopkins et al. 2013a), it is believed that AGN activity is required to drive the highest velocity outflows and are particularly important for the evolution of the most massive galaxies (e.g. Benson et al. 2003; McCarthy et al. 2011; Hopkins et al. 2013b; Zubovas & King 2014). X-ray and ultraviolet spectroscopy has shown that a high fraction, and potentially all, of high accretion rate AGN drive high-velocity outflows ( v ≈ 0.1c) close to their accretion discs (i.e. on subpar- sec scales; e.g. Blustin et al. 2003; Reeves, O’Brien & Ward 2003; Ganguly & Brotherton 2008; Tombesi et al. 2010; Gofford et al. 2011). However, are AGN capable of driving outflows over galaxy scales as is required by galaxy formation models? A diagnostic that is commonly used to identify outflowing gas over large scales is broad (i.e. exceeding that expected from galaxy dynamics), asym- metric and high-velocity [O III ] λ 5007 emission-line profiles. This

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Outflows and particle acceleration in the accretion disks of young stars

Outflows and particle acceleration in the accretion disks of young stars

ranges from several thousand K to 10 −20 K. The accretion disks rotate with nearly Keplerian angular velocity Ω ∝ r −3/2 . Observations reveal outflows from the accretion disks of young stars. The outflows are divided into two groups: low-velocity outflows with v = 10−50 km s −1 and high-velocity well collimated jets with v = 50 − 1000 km s −1 (see review [2]).

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Outflows and disks of brown dwarfs with SMA, CARMA and ALMA

Outflows and disks of brown dwarfs with SMA, CARMA and ALMA

Observations of the statistical properties of young brown dwarfs in different star-forming regions such as the initial mass function, velocity dispersion, multiplicity, accretion disks and jets (see [15] and references therein) have demonstrated that all these properties of BDs appear to form a continuum with those of low-mass stars. The first detections of bipolar molecular outflows from young BDs [23, 24] have indicated that the molecular outflow process occurs in BDs as a scaled-down version of that seen in low-mass stars. All these observations support the scenario that BDs form as low-mass stars do.

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Magnetospheric outflows in young stellar objects

Magnetospheric outflows in young stellar objects

- Stellar winds. Since CTTS are slow rotators and their centrifugal push is not strong enough to drive a stellar wind, an extra energy input is required. It has been proposed by [20] that this could come from the accretion power deposited at the stellar surface by the accreting material (accretion- powered stellar winds), but the functioning and e ffi ciency of the accretion / ejection coupling remains uncertain. For example, it has been estimated by [28] that turbulent Alfvén waves excited by the impact of the accretion streams onto the stellar surface can yield a mass loss rate corresponding to around 1% of the accretion rate at most. These light winds can reach a high terminal speed and could represent a fast component in the inner layers of the observed jets. On the other hand, a stellar wind extracting at least 10% of the accretion rate is necessary to balance the accretion torque [47]. Such a mass loss rate is energetically very demanding and the situation becomes even more critical if the stellar contraction is taken into account [48].

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A distance-limited sample of massive molecular outflows

A distance-limited sample of massive molecular outflows

trally) show some high-velocity components but also multi- ple spectral peaks which confuses the outflow identification. In the distance-limited subset (89 sources) there are 59 def- inite outflows, 17 with outflow like properties and 13 with no outflow evidence. Not all of the sources with outflows show a clear spatial offset of the blue and red-shifted veloc- ity components like G078.1224+03.6320. Given the resolu- tion of the single-dish observations, it is not expected that all spatially offset velocity components would be resolved. There is evidence, however, for a distribution of source in- clinations, as some of the most distant sources, expected to be the least resolved, do exhibit clear spatially offset blue- and red-shifted outflow lobes (e.g. G053.5343 − 00.7943 at 5 kpc). Only two sources appear to have clear outflows close to the plane of the sky associated with the cores (the afore- mentioned G010.8411 − 02.5919 and G109.8715+02.1156, al- though these cores drive multiple distinguishable outflows, see Figure 4). This can also be confirmed as the sources have been previously well studied at radio wavelengths and have very linear radio jets (GGD 27, Marti et al. 1993 and Cep A HW2, Curiel et al. 2006). G203.3166+02.0564 also has a close to plane-of-sky outflow forming a linear struc- ture across the map. This outflow is offset from the source location to the East and the velocity range is optimised only for the outflow associated with our source position (also see Maury et al. 2009, Cunningham et al. 2015, submitted to MNRAS). However, as previously noted we do not identify any isolated, true plane-of-the-sky outflows. It is inherently difficult in these sources to spatially separate the complex core emission from potential plane-of-the-sky outflows and so it is possible that some may be missed as they are simply confused by the core emission.

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“ILLICIT FINANCIAL OUTFLOWS FROM AFRICA” MEASUREMENT AND DETERMINANTS

“ILLICIT FINANCIAL OUTFLOWS FROM AFRICA” MEASUREMENT AND DETERMINANTS

The latest estimates of the Global Financial Integrity (2017) assess the level of illicit financial flows at least to 54 billions of dollars for the year 2014 for the whole African continent. Over the period 2005-2014, the estimation of illicit financial outflows is more than 610 billion of dollars. These resources represent a huge shortfall for African economies knowing the scarcity of financial resources and the structural recourse to external indebtedness. They could have been an important driver for economic and social development, particularly if they are used in productive investment, access to basic services and infrastructure improvements. Instead, these funds are placed in the bank accounts of corrupt officials and traffickers in western countries and tax havens.

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Photoproduction of Jets

Photoproduction of Jets

are several curves from PYTHIA. The two continuous lines show the prediction of PYTHIA with (thicker) and without (thinner) MI. Clearly, MI once more improve the description of the data. Also shown separately are the shapes for those PYTHIA jets which are initiated by a gluon or a quark at LO. Gluon jets are broader in the MC, as expected from the fact that their larger colour charge leads to more QCD radiation. The jets in the rear direction look like quark jets, whereas the behaviour is gluon like in the forward direction. The transition between the two is reproduced in the MC, where it arises from the transition from dominantly direct to dominantly resolved processes as η jet increases. In Fig.6b, the same quantity is plotted, but now

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Advection-dominated accretion: Self-similarity and bipolar outflows

Advection-dominated accretion: Self-similarity and bipolar outflows

We feel that this scenario is a plausible and generic mechanism to produce outflows. For the mechanism to work, we require the outflowing material to re- main adiabatic and to retain its Bernoulli parameter long enough to be accelerated beyond the escape velocity. Given this requirement, we suggest that an outflow can be created merely with viscous and convective redistribution of energy in the manner we have described, without any additional agencies. Hydrodynamic models of outflows have been discussed before by Eggum, Coroniti & Katz (1988), Liang (1988) and Henriksen & Valls-Gabaud (1994). In the former two papers, the outflow is accelerated by radiation pressure, while magnetic stresses appear to play a role in the last work. Radiation and magnetic fields doubtless help, but we suggest that outflows are possible even without them.

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The Nexus between Remittance Outflows and GCC Growth and Inflation

The Nexus between Remittance Outflows and GCC Growth and Inflation

Furthermore, Genc and Naufal (2012) look at the macroeconomic effects of remittance outflows. They point out that most of the foreign labor force hosted by the GCC is low-skilled workers who reside in the GCC countries without being accompanied by their families. This is the main reason why these expatriates remit a large share of their income to their home countries. As discussed above, this may have serious monetary and fiscal policy implications. These implications are aggravated due to the fact that currencies in the GCC are largely pegged to the US dollar. As a result, monetary policy will take a secondary role in the region due to preannounced exchange rates with the US dollar (Genc and Naufal, 2012). Moreover, the volatile oil price has opposite impacts on the United States and GCC countries’ economies, as “remittances provide an avenue to streamline the domestic monetary policy in the GCC by substitution for the nonexistent strong institutional bond market by playing the role of the open market operations” (Genc and Naufal, 2012).

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The Innermost Regions of Relativistic Jets: Wrapping Up the Enigma

The Innermost Regions of Relativistic Jets: Wrapping Up the Enigma

One of the main questions regarding jets is whether they are dominated by Poynting flux or kinetic energy. Most theorists would say that the magnetic field dominates the energy density within 10 4 to 10 6 gravitational radii, be- yond which kinetic flux takes over. Dave Meier proposed that FR I sources remain Poynting flux dominated beyond the main jet acceleration and collimation zone, while FR II objects become kinetic flux dominated. In support of this, Matt Lister reported that, based on the MOJAVE survey with the VLBA, apparent speeds of BL Lac objects tend to increase with distance from the “core,” whereas this is not so common in quasars. John Wardle affirmed the stan- dard result that the electric vectors of the linear polariza- tion of BL Lac objects tend to align with the jet direction, consistent with the helical field expected when Poynting flux dominates. Quasar polarization vectors show no trend on parsec scales (but tend to be transverse to the jet on kpc scales). Dave Meier predicted that BL Lac jets should show signs of non-ballistic motions and kinks, and Mar- shall Cohen found a prominent example in BL Lacertae. On the other hand, there is no shortage of these effects in quasars and BL Lacs, so the test may not be a robust way to discern differences in the energy content of the jets of the two classes.

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Standard Model measurements with the ATLAS detector

Standard Model measurements with the ATLAS detector

Figure 3. Cross-sections for (left) Z+ ≥ 1 b-jet, and (right) Z+ ≥ 2 b-jets. The measurement is shown as a vertical blue line with the inner blue shaded band showing the corresponding statistical uncertainty and the outer green shaded band showing the sum in quadrature of statistical and systematic uncertainties. Comparison is made to NLO predictions from MCFM interfaced to different PDF sets and aMC@NLO interfaced to the same PDF set in both the 4FNS and 5FNS. The statistical (inner bar) and total (outer bar) uncertainties are shown for these predictions, which are dominated by the theoretical scale uncertainty. Comparisons are also made to LO multi-legged predictions from ALPGEN+HERWIG+JIMMY and SHERPA; in this case the uncertainty bars are statistical only, and smaller than the marker [8].

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A construction of Frobenius manifolds from stability conditions

A construction of Frobenius manifolds from stability conditions

which is then flat. It is well known that flatness of this connection is precisely the isomonodromy condition (see e.g. [5, Section 3.3]). Let us focus for a moment on the special case p = 3, i.e. quadratic jets of Frobenius type structures. For generic Z the generalised monodromy of ∇ ζ s ,3 (Z ) can be computed explicitly. We introduce the set of roots (eigen-

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Search for the Higgs boson produced in association with top quarks

Search for the Higgs boson produced in association with top quarks

With respect to inclusive searches of H → γγ we can exploit the photon kinematics, since photons coming from ttH are boosted with respect to those produced with the gluon fusion mechanism and background processes. As in other decay channels we require jets and b-jets in the final state to reduce the background, including that coming from other production mechanism. A full description of the event selection can be found in [5].

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A Comparison between steady jets and synthetic jets at low Reynolds numbers

A Comparison between steady jets and synthetic jets at low Reynolds numbers

significant difference was observed between the steady and synthetic jet Nusselt numbers at low Reynolds numbers and low H/D. In comparison to steady jets, the stronger entrainment of surrounding fluid and the vigorous mixing near the impingement surface are characteristics of synthetic jets that are beneficial to heat transfer. Nonetheless, the steady jet yields higher Nusselt numbers for all test conditions.

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CFD Simulation of Impinging Jet Flows and Boiling Heat Transfer

CFD Simulation of Impinging Jet Flows and Boiling Heat Transfer

Circular jets impinging vertically on flat surfaces have many practical applications such as in heating, cooling, metal cutting, fabric weaving and cleaning. Most of the experiments on impinging jets have been performed for short stand-off distances, i.e., with an impingement height (H) to nozzle diameter (D) ratio of less than six. Cooper et al. (1993) carried out experiments on a jet impinging on a large plane surface and measured mean and turbulence quantities in different regions of the jet. They considered two Reynolds numbers, 23,000 and 70,000, while the H/D ratio varied from two to ten, with particular focus between two and six. For H/D < 6, researchers have found that the core of the jet is still developing when reaching the plate surface (Nishino et al. 1996; Hadziabdic and Hanjalic 2008, Shademan et al. 2013).

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Liquid Fuel Combustion in a Cross-Flow of Multiple Opposing Gaseous Fuel Jets

Liquid Fuel Combustion in a Cross-Flow of Multiple Opposing Gaseous Fuel Jets

Each time the test has been performed, the test rig is ensured to be adjusted in fixed values of flow rates and pressures to make constraints to ensure that results is only because of changing the number of opposing gaseous fuel jets. Also, the parameters were adjusted to make sure the desired intensified, minimum sooty flame occurs for study purposes. Regarding Liquid fuel, a constant pressure was obtained at 15 bar and flow rate was calculated and fixed to 1.116 *10 -3 Kg/s. Gaseous LPG Fuel had a constant flow rate of 3.87 * 10 -4 Kg/s. Air supply required for combustion was set its value of mass flow rate to 0.0355 Kg/s. Overall A/F (Air to Fuel) Ratio was considered as 31.76 for diesel oil burning only and 23.58 for overall diesel oil burning with all opposing gaseous fuel jets cases.

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Alignment between Protostellar Outflows and Filamentary Structure

Alignment between Protostellar Outflows and Filamentary Structure

small scales it is feasible that the underlying structure, turbulence, and/or multiplicity could significantly alter the initial rotation axes. While random alignment is fa- vored in some models of turbulent accretion, even models with strong magnetic fields could result in random align- ment. Mouschovias & Morton (1985) suggested that for fragments linked by strong magnetic fields, the angular momentum orientation of the fragments depends solely on the shape of the magnetic flux tubes, which can have quite irregular shapes. If fragments in filaments are in- deed magnetically linked, our study suggests that the flux tubes connecting them are indeed irregular. The- oretical simulations have begun to incorporate gravity, turbulence, magnetic fields, and outflows to study the formation of filamentary complexes (e.g., Myers et al. 2014; Federrath 2016). Such simulations can supply a more robust expectation of the observed distribution of γ for a large sample of outflows and filaments.

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Indian Capital Control Liberalization: Evidence from NDF Markets

Indian Capital Control Liberalization: Evidence from NDF Markets

whether the incremental moves to liberalize India’s capital controls in recent years have effectively narrowed the barriers to capital inflows and outflows. In this context, we postulate the existence of no-arbitrage bands where the boundaries are determined by transactions costs and limitations to arbitrage due to capital controls, and CIP deviations are random within the boundaries. Using structural break tests, we divide the sample into three sub-samples and estimate the effects of liberalization on the threshold boundaries of the no-arbitrage band and speeds of adjustment. A narrowing of the bands over time is an indication of greater de facto capital account openness, as is an increase in the speed of adjustment to the band threshold points (indicating arbitrage acts more rapidly in returning the market closer to CIP). Inside of the bands, small deviations from CIP follow a process close to a random walk. Outside the bands, profitable and feasible arbitrage opportunities exist, and we estimate an adjustment process back towards the boundaries. We allow for asymmetric boundaries and asymmetric speeds of adjustment (above and below the band thresholds), which may vary depending on how arbitrage activity is constrained by capital controls. We estimate this non-linear model with the self exciting threshold auto-regressions (SETAR) methodology in order to simultaneously obtain consistent estimates of a non-arbitrage band (upper and lower threshold points) and speeds of adjustment (possibly asymmetric) to the boundaries. Outside the thresholds, all of our estimates indicate relatively rapid or instantaneous convergence. This pattern is consistent with the contention that capital controls imply a cost of arbitrage or induce riskiness to the arbitrage position. These unseen costs or risks induce a threshold effect where arbitrage will only become profitable (on a risk adjusted basis) outside a given level of CIP deviation.

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Macroeconomic effects of capital flow structure in sub saharan Africa

Macroeconomic effects of capital flow structure in sub saharan Africa

The influence of capital flows on the macroeconomic stability has been a great concern and examining the effect is of great importance to the macroeconomic policies and risk aversion measures in the recipient countries. Therefore, this study quantitatively analyzed the influences of the capital flows on growth rate of output and inflation rate using several Structural Vector Autoregressive (SVAR) models. The study found that the capital flows have inconclusive effects on output and inflation in the selected African countries from 1985Q1 to 2015Q4. In addition, FDI inflows account for about 20 percent of the macroeconomic fluctuations in the sample period whereas FDI outflows contribute almost 9 percent. The FDI inflows contribute nearly 17 percent fluctuations in Nigeria’s economic growth, and 18 percent of unstable inflation rate in Burkina Faso. On the other hand, 3 percent of fluctuations in the growth of Nigerian economy is explained by its FDI outflows against 0.5 percent in other countries.

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