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Sample records for b-band tully-fisher relation

  1. Kinematics of galaxies in Compact Groups. Studying the B-band Tully-Fisher relation

    CERN Document Server

    Torres-Flores, S; Amram, P; Plana, H; Epinat, B; Carignan, C; Balkowski, C

    2010-01-01

    We obtained new Fabry-Perot data cubes and derived velocity fields, monochromatic and velocity dispersion maps for 28 galaxies in the Hickson compact groups 37, 40, 47, 49, 54, 56, 68, 79 and 93. We find that one third of the non-barred compact group galaxies have position angle misalignments between the stellar and gaseous components. This and the asymmetric rotation curves are clear signatures of kinematic perturbations, probably due to interactions among compact group galaxies. A comparison between the B-band Tully-Fisher relation for compact group galaxies and that for the GHASP field-galaxy sample shows that, despite the high fraction of compact group galaxies with asymmetric rotation curves, these lie on the Tully-Fisher relation defined by galaxies in less dense environments, although with more scatter. This is in agreement with previous results, but now confirmed for a larger sample of 41 galaxies. We confirm the tendency for compact group galaxies at the low-mass end of the Tully-Fisher relation (HCG...

  2. Wave Dark Matter and the Tully-Fisher Relation

    OpenAIRE

    Bray, Hubert L.; Goetz, Andrew S.

    2014-01-01

    We investigate a theory of dark matter called wave dark matter, also known as scalar field dark matter (SFDM) and boson star dark matter or Bose-Einstein condensate (BEC) dark matter, in spherical symmetry and its relation to the Tully-Fisher relation. We show that fixing the oscillation frequency of wave dark matter near the edge of dark galactic halos implies a Tully-Fisher-like relation for those halos. We then describe how this boundary condition, which is roughly equivalent to fixing the...

  3. Impact of Supernova feedback on the Tully-Fisher relation

    CERN Document Server

    De Rossi, Maria E; Pedrosa, Susana E

    2010-01-01

    Recent observational results found a bend in the Tully-Fisher Relation in such a way that low mass systems lay below the linear relation described by more massive galaxies. We intend to investigate the origin of the observed features in the stellar and baryonic Tully-Fisher relations and analyse the role played by galactic outflows on their determination. Cosmological hydrodynamical simulations which include Supernova feedback were performed in order to follow the dynamical evolution of galaxies. We found that Supernova feedback is a fundamental process in order to reproduce the observed trends in the stellar Tully-Fisher relation. Simulated slow rotating systems tend to have lower stellar masses than those predicted by the linear fit to the massive end of the relation, consistently with observations. This feature is not present if Supernova feedback is turned off. In the case of the baryonic Tully-Fisher relation, we also detect a weaker tendency for smaller systems to lie below the linear relation described...

  4. The small scatter of the baryonic Tully-Fisher relation

    CERN Document Server

    Lelli, Federico; Schombert, James M

    2015-01-01

    In a LCDM cosmology, the baryonic Tully-Fisher relation (BTFR) is expected to show significant intrinsic scatter resulting from the mass-concentration relation of dark matter halos and the baryonic-to-halo mass ratio. We study the BTFR using a sample of 118 disc galaxies (spirals and irregulars) with data of the highest quality: extended HI rotation curves (tracing the outer velocity) and Spitzer photometry at 3.6 $\\mu$m (tracing the stellar mass). Assuming that the stellar mass-to-light ratio (M*/L) is nearly constant at 3.6 $\\mu$m, we find that the scatter, slope, and normalization of the BTFR systematically vary with the adopted M*/L. The observed scatter is minimized for M*/L > 0.5, corresponding to nearly maximal discs in high-surface-brightness galaxies and BTFR slopes close to ~4. For any reasonable value of M*/L, the intrinsic scatter is ~0.1 dex, below general LCDM expectations. The residuals show no correlations with galaxy structural parameters (radius or surface brightness), contrary to the predic...

  5. PRECISE TULLY-FISHER RELATIONS WITHOUT GALAXY INCLINATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Obreschkow, D.; Meyer, M. [International Centre for Radio Astronomy Research (ICRAR), M468, University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009 (Australia)

    2013-11-10

    Power-law relations between tracers of baryonic mass and rotational velocities of disk galaxies, so-called Tully-Fisher relations (TFRs), offer a wealth of applications in galaxy evolution and cosmology. However, measurements of rotational velocities require galaxy inclinations, which are difficult to measure, thus limiting the range of TFR studies. This work introduces a maximum likelihood estimation (MLE) method for recovering the TFR in galaxy samples with limited or no information on inclinations. The robustness and accuracy of this method is demonstrated using virtual and real galaxy samples. Intriguingly, the MLE reliably recovers the TFR of all test samples, even without using any inclination measurements—that is, assuming a random sin i-distribution for galaxy inclinations. Explicitly, this 'inclination-free MLE' recovers the three TFR parameters (zero-point, slope, scatter) with statistical errors only about 1.5 times larger than the best estimates based on perfectly known galaxy inclinations with zero uncertainty. Thus, given realistic uncertainties, the inclination-free MLE is highly competitive. If inclination measurements have mean errors larger than 10°, it is better not to use any inclinations than to consider the inclination measurements to be exact. The inclination-free MLE opens interesting perspectives for future H I surveys by the Square Kilometer Array and its pathfinders.

  6. A Transition Mass in the Local Tully-Fisher Relation

    CERN Document Server

    Simons, Raymond C; Weiner, Benjamin J; Heckman, Timothy M; Lee, Janice C; Lotz, Jennifer M; Peth, Michael; Tchernyshyov, Kirill

    2015-01-01

    We study the stellar mass Tully-Fisher relation (TFR, stellar mass versus rotation velocity) for a morphologically blind selection of emission line galaxies in the field at redshifts 0.1 $<$ z $<$ 0.375. Kinematics ($\\sigma_g$, V$_{rot}$) are measured from emission lines in Keck/DEIMOS spectra and quantitative morphology is measured from V- and I-band Hubble images. We find a transition stellar mass in the TFR, $\\log$ M$_*$ = 9.5 M$_{\\odot}$. Above this mass, nearly all galaxies are rotation-dominated, on average more morphologically disk-like according to quantitative morphology, and lie on a relatively tight TFR. Below this mass, the TFR has significant scatter to low rotation velocity and galaxies can either be rotation-dominated disks on the TFR or asymmetric or compact galaxies which scatter off. We refer to this transition mass as the "mass of disk formation", M$_{\\mathrm{df}}$ because above it all star-forming galaxies form disks (except for a small number of major mergers and highly star-forming...

  7. A Tully Fisher Relation for S0 Galaxies

    CERN Document Server

    Neistein, E; Rix, H W; Tonry, J L; Neistein, Eyal; Maoz, Dan; Rix, Hans-Walter; Tonry, John L.

    1999-01-01

    We present an I-band Tully-Fisher relation (TFR) for 18 nearby S0 galaxies using kinematics derived from long slit spectroscopy of stellar absorption lines. Our estimates of the circular velocity, V_c, at 2-3 exponential disk scale lengths account for line-of-sight projection and for the stellar random motions through an asymmetric drift correction. Uniform and accurate distance calibration for all objects is available from surface brightness fluctuation measurements of Tonry et al. (1998). Despite the care taken in estimating both V_c and M_I, the TFR shows an intrinsic scatter, $\\sim 0.7$ mag in M_I, or 0.15 in log_10(V_c). This result is surprising, as S0 galaxies appear to have both the simple kinematics of disk galaxies, and the simple stellar populations of early-type galaxies. Remarkably, in this sample of overall rotation-dominated galaxies, the central stellar velocity dispersion is a better predictor of the total I-band luminosity (through the Fundamental Plane relations) than the circular speed at ...

  8. The different baryonic Tully-Fisher relations at low masses

    CERN Document Server

    Brook, C B; Stinson, G

    2016-01-01

    We compare the Baryonic Tully-Fisher relation (BTFR) of simulations and observations of galaxies ranging from dwarfs to spirals, using various measures of rotational velocity Vrot. We explore the BTFR when measuring Vrot at the flat part of the rotation curve, Vflat, at the extent of HI gas, Vlast, and using 20% (W20) and 50% (W50) of the width of HI line profiles. We also compare with the maximum circular velocity of the parent halo, Vmax, within dark matter only simulations. The different BTFRs increasingly diverge as galaxy mass decreases. Using Vlast one obtains a power law over four orders of magnitude in baryonic mass, with slope similar to the observed BTFR. Measuring Vflat gives similar results as Vlast when galaxies with rising rotation curves are excluded. However, higher rotation velocities would be found for low mass galaxies if the cold gas extended far enough for Vrot to reach a maximum. W20 gives a similar slope as Vlast but with slightly lower values of Vrot for low mass galaxies, although thi...

  9. The Tully-Fisher Relation of COLD GASS Galaxies

    CERN Document Server

    Tiley, Alfred L; Saintonge, Amélie; Topal, Selcuk; Davis, Timothy A; Torii, Kazufumi

    2016-01-01

    We present the stellar mass ($M_{*}$) and Wide-Field Infrared Survey Explorer (WISE) absolute Band 1 magnitude ($M_{W1}$) Tully-Fisher relations (TFRs) of subsets of galaxies from the CO Legacy Database for the Galex Arecibo SDSS Survey (COLD GASS). We examine the benefits and drawbacks of several commonly used fitting functions in the context of measuring CO(1-0) line widths (and thus rotation velocities), favouring the Gaussian Double Peak function. We find the $M_{W1}$ and $M_{*}$ TFR, for a carefully selected sub-sample, to be $M_{W1} = (-7.1\\pm0.6) \\left[\\log{\\left(\\frac{W_{50}/\\sin{i}}{\\text{km~s}^{-1}}\\right)}-2.58\\right] - 23.83\\pm0.09$ and $\\log{(M_{*}/M_{\\odot})} = (3.3\\pm0.3) \\left[\\log{\\left(\\frac{W_{50}/\\sin{i}}{\\text{km~s}^{-1}}\\right)}-2.58\\right] + 10.51\\pm0.04$, respectively, where $W_{50}$ is the width of a galaxy's CO(1-0) integrated profile at $50\\%$ of its maximum and the inclination $i$ is derived from the galaxy axial ratio measured on the SDSS $r$-band image. We find no evidence for an...

  10. An Exploration of the Tully-Fisher Relation for Extreme Late-Type Spiral Galaxies

    CERN Document Server

    Matthews, L D; Gallagher, J S

    1998-01-01

    This paper explores the adherence of 47 extreme late-type galaxies to the B- and V-band Tully-Fisher relations defined by a sample of local calibrators. In both bands we find the mean luminosity at a given line width for extreme late-type spirals to lie below that predicted by standard Tully-Fisher relations. While many of the extreme late-type spirals do follow the Tully-Fisher relation to within our observational uncertainties, most of these galaxies lie below the normal, linear Tully-Fisher relation, and some are underluminous by more than 2 sigma (i.e. >1.16 magnitudes in V). This suggests a possible downward curvature of the Tully-Fisher relation for some of the smallest and faintest rotationally supported disk galaxies. This may be a consequence of the increasing prevalence of dark matter in these systems. We find the deviation from the Tully-Fisher relation to increase with decreasing luminosity and decreasing optical linear size in our sample, implying that the physically smallest and faintest spirals...

  11. The multi-wavelength Tully-Fisher relation: hunting for the intrinsic scatter

    Science.gov (United States)

    Ponomareva, Anastasia

    2016-01-01

    The statistical properties of the Tully-Fisher relation provide important constraints for semi-analytical models and numerical simulations of galaxy formation and evolution. Over the past decades, the scatter in the Tully-Fisher relation has been decreased significantly by accurate photometric measures in the NIR bands. However, the small measurement errors on total luminosity can no longer explain the observed scatter. Therefore, we abandon the classical concept of the Tully-Fisher relation as a correlation using the width of global HI profile and consider instead the internal kinematics of gas in galaxies.As it is still not clear at which wavelengths the smallest scatter in the relation can be achieved, we assemble the Tully-Fisher relation for a calibrator sample of galaxies with measured TRGB/Cepheid distances over the broad wavelength range from FUV to 22 mm. We implement an improved kinematic measure by deriving high quality rotation curves, taking into account warps and streaming motions in the disk due to spiral arms or a bar.As a result, our studies show that besides the wavelength dependence, statistical properties of the Tully-Fisher relation are highly sensitive to the internal kinematics of gas.

  12. Extragalactic SETI: The Tully-Fisher relation as probe of Dysonian astroengineering in disk galaxies

    CERN Document Server

    Zackrisson, E; Asadi, S; Nyholm, A

    2015-01-01

    If advanced extraterrestrial civilizations choose to construct vast numbers of Dyson spheres to harvest radiation energy, this could affect the characteristics of their host galaxies. Potential signatures of such astroengineering projects include reduced optical luminosity, boosted infrared luminosity and morphological anomalies. Here, we apply a technique pioneered by Annis (1999) to search for Kardashev type III civilizations in disk galaxies, based on the predicted offset of these galaxies from the optical Tully-Fisher relation. By analyzing a sample of 1359 disk galaxies, we are able to set a conservative upper limit at 3% on the fraction of local disks subject to Dysonian astroengineering on galaxy-wide scales. However, the available data suggests that a small subset of disk galaxies actually may be underluminous with respect to the Tully-Fisher relation in the way expected for Kardashev type III objects. Based on the optical morphologies and infrared-to-optical luminosity ratios of such galaxies in our ...

  13. Spacetime structure of MOND with Tully-fisher relation and lorentz invariance violation

    International Nuclear Information System (INIS)

    It is believed that the modification of Newtonian dynamics (MOND) is a possible alternative for dark matter hypothesis. Although Bekenstein's TeVeS supplies a relativistic version of MOND, one may still wish for a more concise covariant formulism of MOND. In this paper, within covariant geometrical framework, we present another version of MOND. We show the spacetime structure of MOND with properties of Tully-Fisher relation and Lorentz invariance violation. (authors)

  14. The spacetime structure of MOND with Tully-Fisher relation and Lorentz invariance violation

    OpenAIRE

    Li, Xin; Chang, Zhe

    2012-01-01

    It is believed that the modification of Newtonian dynamics (MOND) is possible alternate for dark matter hypothesis. Although Bekenstein's TeVeS supplies a relativistic version of MOND, one may still wish a more concise covariant formulism of MOND. In this paper, within covariant geometrical framwork, we present another version of MOND. We show the spacetime structure of MOND with properties of Tully-Fisher relation and Lorentz invariance violation.

  15. The Infrared Tully-Fisher Relation in the Ursa-Major Cluster

    OpenAIRE

    Peletier, R. F.; Willner, S. P.

    1993-01-01

    We present new magnitudes derived from 1.65 micron images for 23 galaxies in the Ursa Major cluster. Magnitudes now exist for all but one spiral meeting our criteria for cluster membership and having HI velocity width greater than 187 km/s and inclination greater than 45 deg. These spirals fit a Tully-Fisher relation with dispersion in intrinsic magnitudes (after known observational uncertainties and the effect of cluster depth are removed) of 0.36 and a slope of 10.2 +/- 0.6. The magnitude d...

  16. Tully-Fisher relation, key to dark matter companion of baryonic matter

    CERN Document Server

    Sobouti, Y; Haghi, H

    2009-01-01

    Rotation curves of spiral galaxies \\emph{i}) fall off much less steeply than the Keplerian curves do, and \\emph{ii}) have far-distance asymptotic speeds (almost) proportional to the fourth root of the mass of the galaxy, the Tully-Fisher relation. These features alone are sufficient to assign a dark companion to the galaxy in an unambiguous way. In regions exterior to a spherical system, we design a spherically symmetric spacetime to accommodate the idiosyncracy just quoted. In the weak field regime, an excess gravitation over what the observable matter can produce, emerges. We attribute it to a hypothetical dark perfect fluid companion to the galaxy, and resort to the Tully-Fisher relation to deduce its density and pressure. The dark density turns out to be proportional to the square root of the mass of the galaxy, and to fall off as $r^{-(2+\\alpha)}, ~\\alpha\\ll 1$. The dark equation of state is barrotropic. For the interior of the configuration, we require the continuity of the total force field at the boun...

  17. The baryonic Tully-Fisher Relation predicted by cold dark matter cosmogony

    CERN Document Server

    Desmond, Harry

    2012-01-01

    The baryonic Tully-Fisher Relation (TFR) is a tight relationship observed between baryonic mass and rotational velocity in spiral galaxies. Providing a theoretical basis for the TFR in the Cold Dark Matter (CDM) paradigm has proved problematic: simple calculations suggest too low a slope and too high a scatter. This paper aims to develop a rigorous prediction for the relation in the context of CDM by accounting for all relevant TFR-independent effects observed in numerical simulations of dark matter haloes, including their expected scatter. It is demonstrated that consistent treatment of these effects goes a large way towards reconciling the CDM prediction with the data; the normalisation becomes almost perfect, athough the slope remains somewhat too low. The predicted scatter is indeed too large, but may be reduced to near that of the data by accouting for observational selection effects.

  18. Size matters: abundance matching, galaxy sizes, and the Tully-Fisher relation in EAGLE

    CERN Document Server

    Ferrero, Ismael; Abadi, Mario G; Sales, Laura V; Bower, Richard G; Crain, Robert A; Frenk, Carlos S; Schaller, Matthieu; Schaye, Joop; Theuns, Tom

    2016-01-01

    The Tully-Fisher relation (TFR) links the stellar mass of a disk galaxy, $M_{\\rm str}$, to its rotation speed: it is well approximated by a power law, shows little scatter, and evolves weakly with redshift. The relation has been interpreted as reflecting the mass-velocity scaling ($M\\propto V^3$) of dark matter halos, but this interpretation has been called into question by abundance-matching (AM) models, which predict the galaxy-halo mass relation to be non-monotonic and rapidy evolving. We study the TFR of luminous spirals and its relation to AM using the EAGLE set of $\\Lambda$CDM cosmological simulations. Matching both relations requires disk sizes to satisfy constraints given by the concentration of halos and their response to galaxy assembly. EAGLE galaxies approximately match these constraints and show a tight mass-velocity scaling that compares favourably with the observed TFR. The TFR is degenerate to changes in galaxy formation efficiency and the mass-size relation; simulations that fail to match the...

  19. The Tully-Fisher Relation and Its Residuals for a Broadly Selected Sample of Galaxies

    CERN Document Server

    Pizagno, J; Weinberg, D H; Rix, H W; Pogge, R W; Grebel, E K; Harbeck, D; Blanton, M; Brinkmann, J; Gunn, J E; Pizagno, James; Prada, Francisco; Weinberg, David H.; Rix, Hans-Walter; Pogge, Richard W.; Grebel, Eva K.; Harbeck, Daniel; Blanton, Michael; Gunn, James E.

    2006-01-01

    We measure the relation between galaxy luminosity and disk circular velocity (the Tully-Fisher [TF] relation), in the g, r, i, and z-bands, for a broadly selected sample of galaxies from the Sloan Digital Sky Survey, with the goal of providing well defined observational constraints for theoretical models of galaxy formation. The input sample of 234 galaxies has a roughly flat distribution of absolute magnitudes in the range -18.5 > Mr > -22, and our only morphological selection is an axis-ratio cut b/a < 0.6 to allow accurate inclination corrections. Long-slit spectroscopy yields usable H-alpha rotation curves for 170 galaxies. Observational errors, including distance errors due to peculiar velocities, are small compared to the intrinsic scatter of the TF relation. The slope of the forward TF relation steepens from -5.4 +/- 0.2 mag/log(km/s) in the g-band to -6.4 +/- 0.2 mag/log(km/s) in the z-band. The intrinsic scatter is approximately 0.4 mag in all bands. The scatter is not dominated by rare outliers o...

  20. The Baryonic Tully-Fisher Relation cares about the Galaxy Sample

    CERN Document Server

    G., Sorce Jenny

    2016-01-01

    The Baryonic Tully-Fisher relation (BTFR) is a clear manifestation of the underlying physics of galaxy formation. As such, it is used to constrain and test galaxy formation and evolution models. Of particular interest, apart from the slope of the relation, is its intrinsic scatter. In this paper, we use the EAGLE simulation to study the dependence of the BTFR on the size of the simulated galaxy sample. The huge number of datapoint available in the simulation is indeed not available with current observations. Observational studies that computed the BTFR used various (small) size samples with the only obligation to have galaxies spanning over a large range of masses and rotation rates. Accordingly, to compare observational and theoretical results, we build a large number of various size datasets using the same criterion and derive the BTFR for all of them. Unmistakably, their is an effect of the number of galaxies used to derive the relation. The smaller the number, the larger the standard deviation around the ...

  1. From the Tully-Fisher relation to the Fundamental Plane through Mergers

    CERN Document Server

    Aceves, H; Aceves, Hector; Velazquez, Hector

    2004-01-01

    We set up a series of self-consistent N-body simulations to investigate the fundamental plane of merger remnants of spiral galaxies. These last ones are obtained from a theoretical Tully-Fisher relation at z=1, assuming a constant mass-to-light ratio within the LambdaCDM cosmogony. Using a Sersic growth curve and an orthogonal fitting method, we found that the fundamental plane of our merger remnants is described by the relation Re ~ sigma^{1.48} Ie^{-0.75} which is in good agreement with that reported from the Sloan Digital Sky Survey Re ~ sigma^{1.49} Ie^{-0.75}. However, the R^{1/4}-profile leads to a fundamental plane given by Re ~ sigma^{1.79} Ie^{-0.60}. In general, the correlation found in our merger remnants arises from homology breaking (V^2 ~ sigma^nu, Rg ~ Re^eta) in combination with a mass scaling relation between the total and luminous mass, $M ~ ML^gamma. Considering an orthogonal fitting method, it is found that 1.74

  2. Formation of Disk Galaxies On the Angular Momentum Problem, the Tully-Fisher Relation and Magnetohydrodynamics

    CERN Document Server

    Sommer-Larsen, J

    2000-01-01

    Two ways of possibly solving the angular momentum problem plaguing cold darkmatter (CDM) ab initio simulations of disk galaxy formation are discussed: 1)Stellar feedback processes and 2) Warm dark matter (WDM) rather than CDM. In relation to the chemical evolution of disk galaxies our simulationsindicate that in case 1) the first generation of disk stars formed in diskgalaxies like the Milky Way should have an abundance about two dex below solar,in fairly good agreement with the lowest observed abundance of the metal-weaktail of the Galactic thick disk. For the second case no such statements can bemade without further assumptions about the star-formation history of thegalaxies. We find that the I-band Tully-Fisher relation can be matched by WDM diskgalaxy formation simulations provided (M/L_I) is about 0.8 for disk galaxies,which Sommer-Larsen & Dolgov (1999) argue is a reasonable value. Finally it is discussed how the magnetic field strengths observed in galacticdisks can be obtained through disk galaxy ...

  3. A Slippery Slope: Systematic Uncertainties in the Baryonic Tully-Fisher Relation

    CERN Document Server

    Bradford, Jeremy D; Bosch, Frank C van den

    2016-01-01

    The baryonic Tully-Fisher relation (BTFR) is both a valuable observational tool and a critical test of galaxy formation theory. We explore the systematic uncertainty in the slope and the scatter of the observed BTFR utilizing a homogeneously measured dataset of 930 isolated galaxies. We measure a fiducial relation of log_10 M_baryon = 3.24 log_10 V_rot + 3.21 with a scatter of 0.25 dex over the baryonic mass range of 10^7.4 to 10^11.3 M_sun. We then conservatively vary the definitions of M_baryon and V_rot, the sample definition and the linear fitting algorithm used to fit the BTFR. We obtain slopes ranging from 2.64 to 3.46 and scatter measurements ranging from 0.16 to 0.41 dex. We next compare our fiducial slope to literature measurements, where reported slopes range from 3.0 to 4.3 and scatter is either unmeasured, unmeasurable or as large as 0.4 dex. Measurements derived from unresolved HI line-widths tend to produce slopes of 3.2, while measurements derived strictly from resolved asymptotic rotation velo...

  4. Tully-Fisher relation, galactic rotation curves and dissipative mirror dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Foot, R., E-mail: rfoot@unimelb.edu.au [ARC Centre of Excellence for Particle Physics at the Terascale, School of Physics, University of Melbourne, Victoria 3010 Australia (Australia)

    2014-12-01

    If dark matter is dissipative then the distribution of dark matter within galactic halos can be governed by dissipation, heating and hydrostatic equilibrium. Previous work has shown that a specific model, in the framework of mirror dark matter, can explain several empirical galactic scaling relations. It is shown here that this dynamical halo model implies a quasi-isothermal dark matter density, ρ(r) ≅ ρ{sub 0}r{sub 0}{sup 2}/(r{sup 2}+r{sub 0}{sup 2}), where the core radius, r{sub 0}, scales with disk scale length, r{sub D}, via r{sub 0}/kpc ≈ 1.4(r{sub D}/kpc). Additionally, the product ρ{sub 0}r{sub 0} is roughly constant, i.e. independent of galaxy size (the constant is set by the parameters of the model). The derived dark matter density profile implies that the galactic rotation velocity satisfies the Tully-Fisher relation, L{sub B}∝v{sup 3}{sub max}, where v{sub max} is the maximal rotational velocity. Examples of rotation curves resulting from this dynamics are given.

  5. The Einstein-Klein-Gordon Equations, Wave Dark Matter, and the Tully-Fisher Relation

    CERN Document Server

    Goetz, Andrew S

    2015-01-01

    We examine the Einstein equation coupled to the Klein-Gordon equation for a complex-valued scalar field. These two equations together are known as the Einstein-Klein-Gordon system. In the low-field, non-relativistic limit, the Einstein-Klein-Gordon system reduces to the Poisson-Schr\\"odinger system. We describe the simplest solutions of these systems in spherical symmetry, the spherically symmetric static states, and some scaling properties they obey. We also describe some approximate analytic solutions for these states. The EKG system underlies a theory of wave dark matter, also known as scalar field dark matter (SFDM), boson star dark matter, and Bose-Einstein condensate (BEC) dark matter. We discuss a possible connection between the theory of wave dark matter and the baryonic Tully-Fisher relation, which is a scaling relation observed to hold for disk galaxies in the universe across many decades in mass. We show how fixing boundary conditions at the edge of the spherically symmetric static states implies T...

  6. Tully-Fisher relation, galactic rotation curves and dissipative mirror dark matter

    International Nuclear Information System (INIS)

    If dark matter is dissipative then the distribution of dark matter within galactic halos can be governed by dissipation, heating and hydrostatic equilibrium. Previous work has shown that a specific model, in the framework of mirror dark matter, can explain several empirical galactic scaling relations. It is shown here that this dynamical halo model implies a quasi-isothermal dark matter density, ρ(r) ≅ ρ0r02/(r2+r02), where the core radius, r0, scales with disk scale length, rD, via r0/kpc ≈ 1.4(rD/kpc). Additionally, the product ρ0r0 is roughly constant, i.e. independent of galaxy size (the constant is set by the parameters of the model). The derived dark matter density profile implies that the galactic rotation velocity satisfies the Tully-Fisher relation, LB∝v3max, where vmax is the maximal rotational velocity. Examples of rotation curves resulting from this dynamics are given

  7. Extragalactic SETI: The Tully-Fisher Relation as a Probe of Dysonian Astroengineering in Disk Galaxies

    Science.gov (United States)

    Zackrisson, Erik; Calissendorff, Per; Asadi, Saghar; Nyholm, Anders

    2015-09-01

    If advanced extraterrestrial civilizations choose to construct vast numbers of Dyson spheres to harvest radiation energy, this could affect the characteristics of their host galaxies. Potential signatures of such astroengineering projects include reduced optical luminosity, boosted infrared luminosity, and morphological anomalies. Here, we apply a technique pioneered by Annis to search for Kardashev type III civilizations in disk galaxies, based on the predicted offset of these galaxies from the optical Tully-Fisher (TF) relation. By analyzing a sample of 1359 disk galaxies, we are able to set a conservative upper limit of ≲ 3% on the fraction of local disks subject to Dysonian astroengineering on galaxy-wide scales. However, the available data suggests that a small subset of disk galaxies actually may be underluminous with respect to the TF relation in the way expected for Kardashev type III objects. Based on the optical morphologies and infrared-to-optical luminosity ratios of such galaxies in our sample, we conclude that none of them stand out as strong Kardashev type III candidates and that their inferred properties likely have mundane explanations. This allows us to set a tentative upper limit at ≲ 0.3% on the fraction of Karashev type III disk galaxies in the local universe.

  8. The KMOS Redshift One Spectroscopic Survey (KROSS): The Tully-Fisher Relation at z ~ 1

    CERN Document Server

    Tiley, Alfred L; Swinbank, A M; Bureau, Martin; Harrison, Chris M; Bower, Richard; Johnson, Helen L; Bunker, Andrew J; Jarvis, Matt J; Magdis, Georgios; Sharples, Ray; Smail, Ian; Sobral, David; Best, Philip

    2016-01-01

    We present the stellar mass ($M_{*}$), and K-corrected $K$-band absolute magnitude ($M_{K}$) Tully-Fisher relations (TFRs) for sub-samples of the 584 galaxies spatially resolved in H$\\alpha$ emission by the KMOS Redshift One Spectroscopic Survey (KROSS). We model the velocity field of each of the KROSS galaxies and extract a rotation velocity, $V_{80}$ at a radius equal to the major axis of an ellipse containing 80% of the total integrated H$\\alpha$ flux. The large sample size of KROSS allowed us to select 210 galaxies with well measured rotation speeds. We extract from this sample a further 56 galaxies that are rotationally supported, using the stringent criterion $V_{80}/\\sigma > 3$, where $\\sigma$ is the flux weighted average velocity dispersion. We find the $M_{K}$ and $M_{*}$ TFRs for this sub-sample to be $M_{K} / \\rm{mag}= (-7.3 \\pm 0.9) \\times [(\\log(V_{80}/\\rm{km\\ s^{-1}})-2.25]- 23.4 \\pm 0.2$ , and $\\log(M_{*} / M_{\\odot})= (4.7 \\pm 0.4) \\times [(\\log(V_{80}/\\rm{km\\ s^{-1}}) - 2.25] + 10.0 \\pm 0.3$,...

  9. The baryonic Tully-Fisher relation cares about the galaxy sample

    Science.gov (United States)

    Sorce, Jenny G.; Guo, Quan

    2016-05-01

    The baryonic Tully-Fisher relation (BTFR) is a clear manifestation of the underlying physics of galaxy formation. As such, it is used to constrain and test galaxy formation and evolution models. Of particular interest, apart from the slope of the relation, is its intrinsic scatter. In this article, we use the EAGLE simulation to study the dependence of the BTFR on the size of the simulated galaxy sample. The huge number of data points available in the simulation is indeed not available with current observations. Observational studies that computed the BTFR used various (small) size samples, with the only obligation to have galaxies spanning a large range of masses and rotation rates. Accordingly, to compare observational and theoretical results, we build a large number of various size data sets using the same criterion and derive the BTFR for all of them. Unmistakably, there is an effect resulting from the number of galaxies used to derive the relation. The smaller the number, the larger the standard deviation around the average slope and intrinsic scatter of a given size sample of galaxies. This observation allows us to alleviate the tensions between observational measurements and ΛCDM predictions. Namely, the size of the observational samples adds up to the complexity in comparing observed and simulated relations to discredit or confirm ΛCDM. Similarly, samples, even large, that do not reflect the galaxy distribution give biased results on average. Large size samples reproducing the underlying distribution of galaxies constitute a supplementary necessity to compare observations and simulations efficiently.

  10. The KMOS Redshift One Spectroscopic Survey (KROSS): the Tully-Fisher relation at z ˜ 1

    Science.gov (United States)

    Tiley, Alfred L.; Stott, John P.; Swinbank, A. M.; Bureau, Martin; Harrison, Chris M.; Bower, Richard; Johnson, Helen L.; Bunker, Andrew J.; Jarvis, Matt J.; Magdis, Georgios; Sharples, Ray; Smail, Ian; Sobral, David; Best, Philip

    2016-07-01

    We present the stellar mass (M*), and K-corrected K-band absolute magnitude (MK) Tully-Fisher relations (TFRs) for subsamples of the 584 galaxies spatially resolved in H α emission by the KMOS Redshift One Spectroscopic Survey (KROSS). We model the velocity field of each of the KROSS galaxies and extract a rotation velocity, V80 at a radius equal to the major axis of an ellipse containing 80 per cent of the total integrated H α flux. The large sample size of KROSS allowed us to select 210 galaxies with well-measured rotation speeds. We extract from this sample a further 56 galaxies that are rotationally supported, using the stringent criterion V80/σ > 3, where σ is the flux weighted average velocity dispersion. We find the MK and M* TFRs for this subsample to be MK / {mag}= (-7.3 ± 0.9) × [(log (V_{80}/{km s^{-1}})-2.25]- 23.4 ± 0.2, and log (M_{{*}} / M_{{⊙}})= (4.7 ± 0.4) × [(log (V_{80}/{km s^{-1}}) - 2.25] + 10.0 ± 0.3, respectively. We find an evolution of the M* TFR zero-point of -0.41 ± 0.08 dex over the last ˜8 billion years. However, we measure no evolution in the MK TFR zero-point over the same period. We conclude that rotationally supported galaxies of a given dynamical mass had less stellar mass at z ˜ 1 than the present day, yet emitted the same amounts of K-band light. The ability of KROSS to differentiate, using integral field spectroscopy with KMOS, between those galaxies that are rotationally supported and those that are not explains why our findings are at odds with previous studies without the same capabilities.

  11. The Evolution of the Tully-Fisher Relation Since z~1 with KROSS and SAMI

    Science.gov (United States)

    Tiley, Alfred; Bureau, Martin; Stott, John; Swinbank, Mark; Bower, Richard; Harrison, Christopher; Bunker, Andrew; Smail, Ian; Magdis, Georgios; Johnson, Helen

    2016-01-01

    The KMOS Redshift One Spectroscopic Survey (KROSS) aims to study the spatially-resolved dynamics, star formation and chemistry of ~1000 star-forming galaxies at z~1. Here we begin to probe the epoch of peak star formation in the universe, a key era for galaxy mass assembly. The primary causes of this increased star formation are hotly debated, as are the dominant mechanisms for mass growth (e.g. major mergers, secular evolution). It is thus essential to determine how the ratio of stellar, gaseous and dark mass in galaxies has varied over cosmic time, and whether this is related to the global fall of star formation activity over the same period. Using a simple arctan function to model the spatially-resolved Ha kinematics of the KROSS galaxies, and SED fitting to retrieve stellar masses, I present the observed and baryonic Tully-Fisher relations (TFRs) for sub-samples of the ~400 KROSS galaxies observed. I find a dependence of the KROSS TFRs on the relative importance of rotation and pressure support in galaxies (V/sigma). I explore reasons for the increased intrinsic scatter found in all relations in comparison to z~0. Considering only rotationally supported galaxies (V/sigma > 2.5), there is an apparent evolution of the zero-point of the TFR (-1.8 mag and 0.54 dex for the absolute K-band and stellar mass TFR respectively) since z~1. For a given dynamical mass, galaxies had less stellar mass at z~1 than today. The implications of this for galaxy evolution theory are discussed.Further, when comparing the KROSS TFRs to those at z~0 we must consider the systematic bias introduced as a result of the measurement methods used. To make a direct comparison it is essential to use the same observational and analytical methods. In practice, to compare to KROSS we must take IFU observations of z~0 galaxies and degrade the data to the same signal-to-noise ratio, and spatial and spectral resolution as that of the KROSS data. The degraded data must then be analysed in the same

  12. The Milky Way, The Local Galaxies \\& the IR Tully-Fisher Relation

    OpenAIRE

    Malhotra, Sangeeta; Spergel, David N.; Rhoads, James E; Jing LI

    1996-01-01

    Using the near infrared fluxes of local galaxies derived from COBE/DIRBE J(1.25 $\\mu$m) K (2.2 $\\mu$m) \\& L (3.5 $\\mu$m) band maps and published Cepheid distances, we construct Tully-Fisher (TF) diagrams for the nearby galaxies. The measured dispersions in these luminosity-linewidth diagrams are remarkably small: $\\sigma_J = 0.09$ magnitudes, $\\sigma_K = 0.13$ magnitudes, and $\\sigma_L = 0.20$ magnitudes. For the J and K bands, Monte Carlo simulations give a 95\\% confidence interval upper lim...

  13. The calibration of the WISE W1 and W2 Tully-Fisher relation

    Energy Technology Data Exchange (ETDEWEB)

    Neill, J. D. [California Institute of Technology, 1200 East California Boulevard, MC 278-17, Pasadena, CA 91125 (United States); Seibert, Mark; Scowcroft, Victoria [The Observatories of the Carnegie Institute of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Tully, R. Brent [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Courtois, Hélène; Sorce, Jenny G. [Institut de Physique Nucleaire, Université Claude Bernard Lyon I, F-69100 Lyon (France); Jarrett, T. H. [University of Cape Town, Private Bag X3, Rondebosch 7701, Republic of South Africa (South Africa); Masci, Frank J. [Image Processing and Analysis Center (IPAC), California Institute of Technology, 1200 East California Boulevard, MC 100-22, Pasadena, CA 91125 (United States)

    2014-09-10

    In order to explore local large-scale structures and velocity fields, accurate galaxy distance measures are needed. We now extend the well-tested recipe for calibrating the correlation between galaxy rotation rates and luminosities—capable of providing such distance measures—to the all-sky, space-based imaging data from the Wide-field Infrared Survey Explorer (WISE) W1 (3.4 μm) and W2 (4.6 μm) filters. We find a correlation of line width to absolute magnitude (known as the Tully-Fisher relation, TFR) of M{sub W1}{sup b,i,k,a}=−20.35−9.56(log W{sub mx}{sup i}−2.5) (0.54 mag rms) and M{sub W2}{sup b,i,k,a}=−19.76−9.74(log W{sub mx}{sup i}−2.5) (0.56 mag rms) from 310 galaxies in 13 clusters. We update the I-band TFR using a sample 9% larger than in Tully and Courtois. We derive M{sub I}{sup b,i,k}=−21.34−8.95(log W{sub mx}{sup i}−2.5) (0.46 mag rms). The WISE TFRs show evidence of curvature. Quadratic fits give M{sub W1}{sup b,i,k,a}=−20.48−8.36(log W{sub mx}{sup i}−2.5)+3.60(log W{sub mx}{sup i}−2.5){sup 2} (0.52 mag rms) and M{sub W2}{sup b,i,k,a}=−19.91−8.40(log W{sub mx}{sup i}−2.5)+4.32(log W{sub mx}{sup i}−2.5){sup 2} (0.55 mag rms). We apply an I-band –WISE color correction to lower the scatter and derive M{sub C{sub W{sub 1}}}=−20.22−9.12(log W{sub mx}{sup i}−2.5) and M{sub C{sub W{sub 2}}}=−19.63−9.11(log W{sub mx}{sup i}−2.5) (both 0.46 mag rms). Using our three independent TFRs (W1 curved, W2 curved, and I band), we calibrate the UNION2 Type Ia supernova sample distance scale and derive H {sub 0} = 74.4 ± 1.4(stat) ± 2.4(sys) km s{sup –1} Mpc{sup –1} with 4% total error.

  14. Disk galaxy scaling relations at intermediate redshifts. I. The Tully-Fisher and velocity-size relations

    Science.gov (United States)

    Böhm, Asmus; Ziegler, Bodo L.

    2016-07-01

    Aims: Galaxy scaling relations such as the Tully-Fisher relation (between the maximum rotation velocity Vmax and luminosity) and the velocity-size relation (between Vmax and the disk scale length) are powerful tools to quantify the evolution of disk galaxies with cosmic time. Methods: We took spatially resolved slit spectra of 261 field disk galaxies at redshifts up to z ≈ 1 using the FORS instruments of the ESO Very Large Telescope. The targets were selected from the FORS Deep Field and William Herschel Deep Field. Our spectroscopy was complemented with HST/ACS imaging in the F814W filter. We analyzed the ionized gas kinematics by extracting rotation curves from the two-dimensional spectra. Taking into account all geometrical, observational, and instrumental effects, these rotation curves were used to derive the intrinsic Vmax. Results: Neglecting galaxies with disturbed kinematics or insufficient spatial rotation curve extent, Vmax was reliably determined for 124 galaxies covering redshifts 0.05 http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/592/A64

  15. Disk galaxy scaling relations at intermediate redshifts - I. The Tully-Fisher and velocity-size relations

    CERN Document Server

    Boehm, Asmus

    2015-01-01

    Galaxy scaling relations such as the Tully-Fisher relation (between maximum rotation velocity Vmax and luminosity) and the velocity-size relation (between Vmax and disk scale length) are powerful tools to quantify the evolution of disk galaxies with cosmic time. We took spatially resolved slit spectra of 261 field disk galaxies at redshifts up to z~1 using the FORS instruments of the ESO Very Large Telescope. The targets were selected from the FORS Deep Field and William Herschel Deep Field. Our spectroscopy was complemented with HST/ACS imaging in the F814W filter. We analyzed the ionized gas kinematics by extracting rotation curves from the 2-D spectra. Taking into account all geometrical, observational and instrumental effects, these rotation curves were used to derive the intrinsic Vmax. Neglecting galaxies with disturbed kinematics or insufficient spatial rotation curve extent, Vmax could be determined for 137 galaxies covering redshifts 0.05

  16. The Hubble Space Telescope Key Project on the Extragalactic Distance Scale; 24, The Calibration of Tully-Fisher Relations and the Value of the Hubble Constant

    CERN Document Server

    Sakai, S; Hughes, S M G; Huchra, J P; Macri, L M; Kennicutt, R C; Gibson, B K; Ferrarese, L; Freedman, W L; Han, M; Ford, H C; Graham, J A; Illingworth, G D; Kelson, D D; Madore, B F; Sebo, K; Silbermann, N A; Stetson, P B; Sakai, Shoko; Mould, Jeremy R.; Hughes, Shaun M.G.; Huchra, John P.; Macri, Lucas M.; Kennicutt, Robert C.; Gibson, Brad K.; Ferrarese, Laura; Freedman, Wendy L.; Han, Mingsheng; Ford, Holland C.; Graham, John A.; Illingworth, Garth D.; Kelson, Daniel D.; Madore, Barry F.; Sebo, Kim; Silbermann, Nancy A.; Stetson, Peter B.

    1999-01-01

    This paper presents the calibration of BVRIH$ Tully-Fisher relations based on Cepheid distances to 21 galaxies within 25 Mpc, and 23 clusters within 10,000 km/s. These relations have been applied to several distant cluster surveys in order to derive a value for the Hubble constant, H0, mainly concentrating on an I-band all-sky survey by Giovanelli and collaborators which consisted of total I magnitudes and 50% linewidth data for ~550 galaxies in 16 clusters. For comparison, we also derive the values of H0 using surveys in B-band and V-band by Bothun and collaborators, and in H-band by Aaronson and collaborators. Careful comparisons with various other databases from literature suggest that the H-band data, whose magnitudes are isophotal magnitudes extrapolated from aperture magnitudes rather than total magnitudes, are subject to systematic uncertainties. Taking a weighted average of the estimates of Hubble constants from four surveys, we obtain H0 = 71 +- 4 (random) +- 7 (systematic) km/s/Mpc. We have also inv...

  17. THE BARYONIC TULLY-FISHER RELATION OF GAS-RICH GALAXIES AS A TEST OF ΛCDM AND MOND

    International Nuclear Information System (INIS)

    The baryonic Tully-Fisher relation (BTFR) is an empirical relation between baryonic mass and rotation velocity in disk galaxies. It provides tests of galaxy formation models in ΛCDM and of alternative theories like modified Newtonian dynamics (MOND). Observations of gas-rich galaxies provide a measure of the slope and normalization of the BTFR that is more accurate (if less precise) than that provided by star-dominated spirals, as their masses are insensitive to the details of stellar population modeling. Recent independent data for such galaxies are consistent with Mb = AV4f with A = 47 ± 6 M☉ km–4 s4. This is equivalent to MOND with a0 = 1.3 ± 0.3 Å s–2. The scatter in the data is consistent with being due entirely to observational uncertainties. It is unclear why the physics of galaxy formation in ΛCDM happens to pick out the relation predicted by MOND. We introduce a feedback efficacy parameter E to relate halo properties to those of the galaxies they host. E correlates with star formation rate and gas fraction in the sense that galaxies that have experienced the least star formation have been most impacted by feedback.

  18. An accurate measurement of the baryonic Tully-Fisher relation with heavily gas-dominated ALFALFA galaxies

    CERN Document Server

    Papastergis, E; van der Hulst, J M

    2016-01-01

    We use a sample of 97 galaxies selected from the ALFALFA 21cm survey to make an accurate measurement of the baryonic Tully-Fisher relation (BTFR). These galaxies are specifically selected to be heavily gas-dominated (Mgas/M* >~ 2.7) and to be oriented edge-on. The former property ensures that the error on the galactic baryonic mass is small, despite the large systematic uncertainty involved in galactic stellar mass estimates. The latter property means that rotational velocities can be derived directly from the width of the 21cm emission line, without any need for inclination corrections. The resulting linewidth-based BTFR has a slope of alpha = 3.58 +- 0.11, a value that is in agreement with previous literature results. The relation is remarkably tight, with almost all galaxies being located within a perpendicular distance of +- 0.1 dex from the best fit line. The low observational error budget for our sample allows us to establish that, despite its tightness, the measured linewidth-based BTFR has some small ...

  19. S0 galaxies in the Coma cluster: Environmental dependence of the S0 offset from the Tully-Fisher relation

    CERN Document Server

    Rawle, T D; Smith, Russell J; Head, J T C G

    2013-01-01

    We present deep GMOS long-slit spectroscopy of 15 Coma cluster S0 galaxies, and extract kinematic properties along the major axis to several times the disc scale-length. Supplementing our dataset with previously published data, we create a combined sample of 29 Coma S0s, as well as a comparison sample of 38 Coma spirals. Using photometry from SDSS and 2MASS, we construct the Tully-Fisher relation (TFR; luminosity versus maximum rotational velocity) for S0 galaxies. At fixed rotational velocity, the Coma S0 galaxies are on average fainter than Coma spirals by 1.10$\\pm$0.18, 0.86$\\pm$0.19 and 0.83$\\pm$0.19 mag in the g, i and Ks bands respectively. The typical S0 offsets remain unchanged when calculated relative to large field-galaxy spiral samples. The observed offsets are consistent with a simple star formation model in which S0s are identical to spirals until abrupt quenching occurs at some intermediate redshift. The offsets form a continuous distribution tracing the time since the cessation of star formatio...

  20. Testing cold dark matter with the low mass Tully-Fisher relation

    OpenAIRE

    Blanton, Michael R.; Geha, Marla; West, Andrew A.

    2007-01-01

    The galaxy circular velocity function at small masses is related to the matter power spectrum on small scales. Although this function is well-studied for Local Group dwarfs, theoretical predictions and observational measurements are difficult for satellite galaxies, because of ram pressure and tidal stripping. By contrast, isolated dwarf galaxies are less affected by these processes, and almost always have enough 21cm emission to trace their dynamics robustly. Here, we test cold dark matter c...

  1. An accurate measurement of the baryonic Tully-Fisher relation with heavily gas-dominated ALFALFA galaxies

    Science.gov (United States)

    Papastergis, E.; Adams, E. A. K.; van der Hulst, J. M.

    2016-09-01

    We use a sample of 97 galaxies selected from the Arecibo legacy fast ALFA (ALFALFA) 21 cm survey to make an accurate measurement of the baryonic Tully-Fisher relation (BTFR). These galaxies are specifically selected to be heavily gas-dominated (Mgas/M∗ ≳ 2.7) and to be oriented edge-on. The former property ensures that the error on the galactic baryonic mass is small, despite the large systematic uncertainty involved in galactic stellar mass estimates. The latter property means that rotational velocities can be derived directly from the width of the 21 cm emission line, without any need for inclination corrections. We measure a slope for the linewidth-based BTFR of α = 3.75 ± 0.11, a value that is somewhat steeper than (but in broad agreement with) previous literature results. The relation is remarkably tight, with almost all galaxies being located within a perpendicular distance of ± 0.1 dex from the best fit line. The low observational error budget for our sample enables us to establish that, despite its tightness, the measured linewidth-based BTFR has some small (i.e., non-zero) intrinsic scatter. We furthermore find a systematic difference in the BTFR of galaxies with "double-horned" 21 cm line profiles - suggestive of flat outer galactic rotation curves - and those with "peaked" profiles - suggestive of rising rotation curves. When we restrict our sample of galaxies to objects in the former category, we measure a slightly steeper slope of α = 4.13 ± 0.15. Overall, the high-accuracy measurement of the BTFR presented in this article is intended as a reliable observational benchmark against which to test theoretical expectations. Here we consider a representative set of semi-analytic models and hydrodynamic simulations in the lambda cold dark matter (ΛCDM) context, as well as modified Newtonian dynamics (MOND). In the near future, interferometric follow-up observations of several sample members will enable us to further refine the BTFR measurement, and

  2. Testing cold dark matter with the low mass Tully-Fisher relation

    CERN Document Server

    Blanton, Michael R; West, Andrew A

    2007-01-01

    The galaxy circular velocity function at small masses is related to the matter power spectrum on small scales. Although this function is well-studied for Local Group dwarfs, theoretical predictions and observational measurements are difficult for satellite galaxies, because of ram pressure and tidal stripping. By contrast, isolated dwarf galaxies are less affected by these processes, and almost always have enough 21cm emission to trace their dynamics robustly. Here, we test cold dark matter cosmology using isolated low mass dwarf galaxies from the SDSS with measured 21cm widths. We find consistency between the predicted and observed number density of isolated galaxies down to circular velocities of 50 km/s. Our technique yields a direct test of small-scale cosmology independent of the Lyman-alpha forest power spectrum, but our sample is currently statistically less powerful: warm dark matter particles heavier than 0.5 keV cannot be ruled out. Our major systematic uncertainty is the surface brightness limit of...

  3. WISE TF: A MID-INFRARED, 3.4 μm EXTENSION OF THE TULLY-FISHER RELATION USING WISE PHOTOMETRY

    International Nuclear Information System (INIS)

    We present a mid-infrared Tully-Fisher (TF) relation using photometry from the 3.4 μm W1 band of the Wide-field Infrared Survey Explorer (WISE) satellite. The WISE TF relation is formed from 568 galaxies taken from the all-sky 2MASS Tully-Fisher (2MTF) galaxy catalog, spanning a range of environments including field, group, and cluster galaxies. This constitutes the largest mid-infrared TF relation constructed to date. After applying a number of corrections to galaxy magnitudes and line widths, we measure a master TF relation given by Mcorr = –22.24 – 10.05[log (Wcorr) – 2.5], with an average dispersion of σWISE = 0.686 mag. There is some tension between WISE TF and a preliminary 3.6 μm relation, which has a shallower slope and almost no intrinsic dispersion. However, our results agree well with a more recent relation constructed from a large sample of cluster galaxies. We additionally compare WISE TF to the near-infrared 2MTF template relations, finding a good agreement between the TF parameters and total dispersions of WISE TF and the 2MTF K-band template. This fact, coupled with typical galaxy colors of (K – W1) ∼ 0, suggests that these two bands are tracing similar stellar populations, including the older, centrally-located stars in the galactic bulge which can (for galaxies with a prominent bulge) dominate the light profile.

  4. The effect of Warm Dark Matter on galaxy properties: constraints from the stellar mass function and the Tully-Fisher relation

    CERN Document Server

    Kang, Xi; Dutton, Aaron A

    2012-01-01

    In this paper we combine high resolution N-body simulations with a semi analytical model of galaxy formation to study the effects of a possible Warm Dark Matter (WDM) component on the observable properties of galaxies. We compare three WDM models with a dark matter mass of 0.5, 0.75 and 2.0 keV, with the standard Cold Dark Matter case. For a fixed set of parameters describing the baryonic physics the WDM models predict less galaxies at low (stellar) masses, as expected due to the suppression of power on small scales, while no substantial difference is found at the high mass end. However these differences in the stellar mass function, vanish when different set of parameters are used to describe the (largely unknown) galaxy formation processes. We show that is possible to break this degeneracy between DM properties and the parameterization of baryonic physics by combining observations on the stellar mass function with the Tully-Fisher relation (the relation between stellar mass and the rotation velocity at larg...

  5. Dynamical properties of AMAZE and LSD galaxies from gas kinematics and the Tully-Fisher relation at z~3

    CERN Document Server

    Gnerucci, A; Cresci, G; Maiolino, R; Mannucci, F; Calura, F; Cimatti, A; Cocchia, F; Grazian, A; Matteucci, F; Nagao, T; Pozzetti, L; Troncoso, P

    2010-01-01

    We present a SINFONI integral field kinematical study of 33 galaxies at z~3 from the AMAZE and LSD projects which are aimed at studying metallicity and dynamics of high-redshift galaxies. The number of galaxies analyzed in this paper constitutes a significant improvement compared to existing data in the literature and this is the first time that a dynamical analysis is obtained for a relatively large sample of galaxies at z~3. 11 galaxies show ordered rotational motions ($\\sim 30\\%$ of the sample), in these cases we estimate dynamical masses by modeling the gas kinematics with rotating disks and exponential mass distributions. We find dynamical masses in the range 2 10^9 Msun -2 10^11 Msun with a mean value of ~2\\ 10^10 Msun. By comparing observed gas velocity dispersion with that expected from models, we find that most rotatin objects are dynamically "hot", with intrinsic velocity dispersions of the order of ~90 km/s. The median value of the ratio between the maximum disk rotational velocity and the intrinsi...

  6. Tully-Fisher Scalings and Boundary Conditions for Wave Dark Matter

    OpenAIRE

    Goetz, Andrew S.

    2015-01-01

    We investigate a theory of dark matter called wave dark matter, also known as scalar field dark matter (SFDM) and boson star dark matter or Bose-Einstein condensate (BEC) dark matter (also see axion dark matter), and its relation to the Tully-Fisher relation. We exhibit two boundary conditions that give rise to Tully-Fisher-like relations for spherically symmetric static wave dark matter halos: (BC1) Fixing a length scale at the outer edge of wave dark matter halos gives rise to a Tully-Fishe...

  7. Detailed HI kinematics of Tully-Fisher calibrator galaxies

    CERN Document Server

    Ponomareva, Anastasia A; Bosma, Albert

    2016-01-01

    We present spatially-resolved HI kinematics of 32 spiral galaxies which have Cepheid or/and Tip of the Red Giant Branch distances, and define a calibrator sample for the Tully-Fisher relation. The interferometric HI data for this sample were collected from available archives and supplemented with new GMRT observations. This paper describes an uniform analysis of the HI kinematics of this inhomogeneous data set. Our main result is an atlas for our calibrator sample that presents global HI profiles, integrated HI column-density maps, HI surface density profiles and, most importantly, detailed kinematic information in the form of high-quality rotation curves derived from highly-resolved, two-dimensional velocity fields and position-velocity diagrams.

  8. Tully-Fisher analysis of the multiple cluster system Abell 901/902

    CERN Document Server

    Bösch, Benjamin; Wolf, Christian; Aragón-Salamanca, Alfonso; Ziegler, Bodo L; Barden, Marco; Gray, Meghan E; Balogh, Michael; Meisenheimer, Klaus; Schindler, Sabine

    2013-01-01

    We derive rotation curves from optical emission lines of 182 disk galaxies (96 in the cluster and 86 in the field) in the region of Abell 901/902 located at $z\\sim 0.165$. We focus on the analysis of B-band and stellar-mass Tully-Fisher relations. We examine possible environmental dependencies and differences between normal spirals and "dusty red" galaxies, i.e. disk galaxies that have red colors due to relatively low star formation rates. We find no significant differences between the best-fit TF slope of cluster and field galaxies. At fixed slope, the field population with high-quality rotation curves (57 objects) is brighter by $\\Delta M_{B}=-0\\fm42\\pm0\\fm15$ than the cluster population (55 objects). We show that this slight difference is at least in part an environmental effect. The scatter of the cluster TFR increases for galaxies closer to the core region, also indicating an environmental effect. Interestingly, dusty red galaxies become fainter towards the core at given rotation velocity (i.e. total mas...

  9. Optical Rotation Curves and Linewidths for Tully-Fisher Applications

    CERN Document Server

    Courteau, S

    1997-01-01

    We present optical long-slit rotation curves (RCs) for 304 northern Sb-Sc UGC galaxies originally selected for Tully-Fisher (TF) applications. 20% of the galaxies were observed twice or more, allowing for a proper determination of systematic errors. Various measures of maximum rotational velocity to be used as input in the TF relation are tested on the basis of their repeatability, minimization of TF scatter, and match with 21cm linewidths. The best measure of TF velocity, v2.2, is given at the location of peak rotational velocity of a pure exponential disk. Optical TF calibrations yield internal scatter comparable to, if not smaller than, the best calibrations based on single-dish 21cm radio linewidths. Even though resolved HI RCs are more extended than their optical counterpart, a tight match between optical and radio linewidths exists since the bulk of the HI surface density is enclosed within the optical radius. We model the 304 RCs presented here and a sample of 958 curves from Mathewson etal. (1992) wit...

  10. GHASP: an H$\\alpha$ kinematic survey of spiral galaxies - X. Surface photometry, decompositions and the Tully-Fisher relation in the Rc-band

    CERN Document Server

    Barbosa, C E; Amram, P; Ferrari, F; Russeil, D; Epinat, B; Perret, V; Adami, C; Marcelin, M

    2015-01-01

    We present Rc-band surface photometry for 170 of the 203 galaxies in GHASP, Gassendi H-Alpha survey of SPirals, a sample of late-type galaxies for which high-resolution Fabry-Perot H{\\alpha} maps have previously been obtained. Our data set is constructed by new Rc-band observations taken at the Observatoire de Haute-Provence (OHP), supplemented with Sloan Digital Sky Survey (SDSS) archival data, obtained with the purpose of deriving homogeneous photometric profiles and parameters. Our results include Rc-band surface brightness profiles for 170 galaxies and $ugriz$ profiles for 108 of these objects. We catalogue several parameters of general interest for further reference, such as total magnitude, effective radius and isophotal parameters -- magnitude, position angle, ellipticity and inclination. We also perform a structural decomposition of the surface brightness profiles using a multi-component method in order to separate disks from bulges and bars, and to observe the main scaling relations involving luminos...

  11. Bias properties of extragalactic distance indicators. 3: Analysis of Tully-Fisher distances for the Mathewson-Ford-Buchhorn sample of 1355 galaxies

    Science.gov (United States)

    Federspiel, Martin; Sandage, Allan; Tammann, G. A.

    1994-01-01

    The observational selection bias properties of the large Mathewson-Ford-Buchhorn (MFB) sample of axies are demonstrated by showing that the apparent Hubble constant incorrectly increases outward when determined using Tully-Fisher (TF) photometric distances that are uncorreted for bias. It is further shown that the value of H(sub 0) so determined is also multivlaued at a given redshift when it is calculated by the TF method using galaxies with differenct line widths. The method of removing this unphysical contradiction is developed following the model of the bias set out in Paper II. The model developed further here shows that the appropriate TF magnitude of a galaxy that is drawn from a flux-limited catalog not only is a function of line width but, even in the most idealistic cases, requires a triple-entry correction depending on line width, apparent magnitude, and catalog limit. Using the distance-limited subset of the data, it is shown that the mean intrinsic dispersion of a bias-free TF relation is high. The dispersion depends on line width, decreasing from sigma(M) = 0.7 mag for galaxies with rotational velocities less than 100 km s(exp-1) to sigma(M) = 0.4 mag for galaxies with rotational velocities greater than 250 km s(exp-1). These dispersions are so large that the random errors of the bias-free TF distances are too gross to detect any peculiar motions of individual galaxies, but taken together the data show again the offset of 500 km s(exp-1) fond both by Dressler & Faber and by MFB for galaxies in the direction of the putative Great Attractor but described now in a different way. The maximum amplitude of the bulk streaming motion at the Local Group is approximately 500 km s(exp-1) but the perturbation dies out, approaching the Machian frame defined by the CMB at a distance of approximately 80 Mpc (v is approximately 4000 km s(exp -1)). This decay to zero perturbation at v is approximately 4000 km s(exp -1) argues against existing models with a single

  12. Scaling Relations in the High-z Universe with Lensing and MUSE

    Science.gov (United States)

    Lagattuta, David James; Richard, Johan; Clément, Benjamin; Patricio, Vera; Mahler, Guillaume

    2015-08-01

    We present new gravitational lensing models for giant arcs in the Frontier Fields galaxy clusters, incorporating cluster- and galaxy-scale substructure to improve the model fit. From these models we are able to reconstruct the un-lensed properties of the arcs, including morphology and total luminosity. Combining this information with 2D kinematic data from MUSE spectroscopy, we are further able to construct a high redshift (z > 1) Tully-Fisher (TF) relation, which -- when compared to its lower redshift counterparts -- can be used to probe the evolution of the TF relation over cosmological time.

  13. The KMOS Redshift One Spectroscopic Survey (KROSS) : the Tully–Fisher relation at z ∼ 1.

    OpenAIRE

    Tiley, AL; Stott, JP; Swinbank, AM; Bureau, M.; Harrison, CM; Bower, R.; Johnson, HL; Bunker, AJ; Jarvis, MJ; Magdis, G.; Sharples, R.; Smail, I.; Sobral, D.; Best, P.

    2016-01-01

    We present the stellar mass ($M_{*}$), and K-corrected $K$-band absolute magnitude ($M_{K}$) Tully-Fisher relations (TFRs) for sub-samples of the 584 galaxies spatially resolved in H$\\alpha$ emission by the KMOS Redshift One Spectroscopic Survey (KROSS). We model the velocity field of each of the KROSS galaxies and extract a rotation velocity, $V_{80}$ at a radius equal to the major axis of an ellipse containing 80% of the total integrated H$\\alpha$ flux. The large sample si...

  14. Scaling relations for galaxies of all types with CALIFA and MaNGA surveys.

    Science.gov (United States)

    Aquino-Ortíz, E.; Sánchez-Sánchez, S. F.; Valenzuela, O.; Cano-Díaz, M.; Hernández-Toledo, H.

    2016-06-01

    We used gas and stellar kinematics for the final Data Release of 667 spatially resolved galaxies publicly available from Calar Alto Legacy Integral Field Area survey (CALIFA) with the aim of study dynamical scaling relations as Tully & Fisher for rotation velocity, Faber & Jackson for velocity dispersion and also a combination of them through the S_{K} parameter defined as S_{K}^2 = KV_{rot}^2 + σ^2. We found a offset between gas and stellar kinematics in Tully & Fisher and Faber & Jackson relations, however when we used the S_{K} parameter all galaxies regardless of the morphological type lie in this M_{*} vs S_{k} scaling relation with a significant improvement compared with the M_{*} vs V_{rot} and M_{*} vs σ relations, in agreement with previous studies with SAMI survey, however the slope ant zero-point are different with them. We also explored different values of the K parameter, as well as different proxys to estimate V_{rot} in order to understand and characterize the physical source of scatter, slope and zero-point.

  15. MOND implications for spectral line profiles of shell galaxies: shell formation history and mass-velocity scaling relations

    Science.gov (United States)

    Bílek, M.; Jungwiert, B.; Ebrová, I.; Bartošková, K.

    2015-03-01

    Context. Many ellipticals are surrounded by round stellar shells probably stemming from minor mergers. A new method for constraining gravitational potential in elliptical galaxies has recently been suggested. It uses the spectral line profiles of these shells to measure the circular velocity at the edge of the shell and the expansion velocity of the shell itself. MOND is an alternative to the dark matter framework aiming to solve the missing mass problem. Aims: We study how the circular and expansion velocities behave in MOND for large shells. Methods: The asymptotic behavior for infinitely large shells is derived analytically. The applicability of the asymptotic results for finitely sized shells is studied numerically on a grid of galaxies modeled with Sérsic spheres. Results: Circular velocity settles asymptotically at a value determined by the baryonic mass of the galaxy forming the baryonic Tully-Fisher relation known for disk galaxies. Shell expansion velocity also becomes asymptotically constant. The expansion velocities of large shells form a multibranched analogy to the baryonic Tully-Fisher relation, together with the galactic baryonic masses. For many - but not all - shell galaxies, the asymptotic values of these two types of velocities are reached under the effective radius. If MOND is assumed to work in ellipticals, then the shell spectra allow many details of the history to be revealed about the formation of the shell system, including its age. The results pertaining to circular velocities apply to all elliptical galaxies, not only those with shells.

  16. Implications and Applications of Kinematic Galaxy Scaling Relations

    CERN Document Server

    Zaritsky, Dennis

    2012-01-01

    Galaxy scaling relations, which describe a connection between ostensibly unrelated physical characteristics of galaxies, testify to an underlying order in galaxy formation that requires understanding. I review the development of a scaling relation that 1) unites the well-known Fundamental Plane (FP) relation of giant elliptical galaxies and Tully-Fisher (TF) relation of disk galaxies, 2) fits low mass spheroidal galaxies, including the ultra-faint satellites of our Galaxy, 3) explains the apparent shift of lenticular (S0) galaxies relative to both FP or TF, 3) describes all stellar dynamical systems, including systems with no dark matter (stellar clusters), 4) associates explicitly the numerical coefficients that account for the apparent "tilt" of the FP away from the direct expectation drawn from the virial theorem with systematic variations in the total mass-to-light ratio of galaxies within the half-light radius, 5) connects with independent results that demonstrate the robustness of mass estimators when a...

  17. MOND implications for spectral line profiles of shell galaxies: shell formation history and mass-velocity scaling relations

    CERN Document Server

    Bílek, Michal; a, Ivana Ebrov\\'; a, Kateřina Bartoškov\\'

    2014-01-01

    CONTEXT. Many ellipticals are surrounded by round stellar shells originating probably from minor mergers. A new method for constraining gravitational potential in elliptical galaxies was recently suggested. It uses the spectral line profiles of these shells to measure the circular velocity at the edge of the shell and the expansion velocity of the shell itself. MOND is an alternative to the dark matter framework aiming to solve the missing mass problem. AIMS. We study how the circular and expansion velocities behave in MOND for large shells. METHODS. The asymptotic behavior for infinitely large shells is derived analytically. The applicability of the asymptotic results for finitely sized shells is studied numerically on a grid galaxies modeled by S\\' ersic spheres. RESULTS. Circular velocity asymptotically settles at a value determined by the baryonic mass of the galaxy forming the baryonic Tully-Fisher relation known for disk galaxies. Shell expansion velocity also becomes asymptotically constant. The expans...

  18. On the photodissociation of uranium hexafluoride in the B band

    Science.gov (United States)

    Menghini, M.; Morales, P.; Dore, P.; Schisano, M. I.

    1986-06-01

    The rate of photodissociation of uranium hexafluoride is measured for the first time as a function of wavelength in the B band. The experimental technique used tests the collision-free behavior and, with the addition of a buffer gas, the collisional effects on molecular relaxation. In both cases, the dissociation yield is strongly nonuniform. A qualitative interpretation of these results is attempted. Their relevance to the subject of laser isotopic separation and more generally of selective photochemistry is outlined.

  19. NIR Tully-Fisher in the Zone of Avoidance. -- III. Deep NIR catalogue of the HIZOA galaxies

    CERN Document Server

    Said, Khaled; Jarrett, T H; Staveley-Smith, Lister; Williams, Wendy L

    2016-01-01

    We present a deep near-infrared (NIR) photometric catalogue of sources from the Parkes HI Zone of Avoidance (HIZOA) survey, which forms the basis for an investigation of the matter distribution in the Zone of Avoidance. Observations were conducted between 2006 and 2013 using the Infrared Survey Facility (IRSF), a 1.4-m telescope situated at the South African Astronomical Observatory site in Sutherland. The images cover all 1108 HIZOA detections and yield 915 galaxies. An additional 105 bright 2MASS galaxies in the southern ZOA were imaged with the IRSF, resulting in 129 galaxies. The average $K_s$-band seeing and sky background for the survey are 1.38 arcsec and 20.1 mag, respectively. The detection rate as a function of stellar density and dust extinction is found to depend mainly on the HI mass of the HI detected galaxies, which in principal correlates with the NIR brightness of the spiral galaxies. The measured isophotal magnitudes are of sufficient accuracy (errors $\\sim$ 0.02 mag) to be used in a Tully-F...

  20. The mass discrepancy acceleration relation in a ΛCDM context

    Science.gov (United States)

    Di Cintio, Arianna; Lelli, Federico

    2016-02-01

    The mass discrepancy acceleration relation (MDAR) describes the coupling between baryons and dark matter (DM) in galaxies: the ratio of total-to-baryonic mass at a given radius anticorrelates with the acceleration due to baryons. The MDAR has been seen as a challenge to the Λ cold dark matter (ΛCDM) galaxy formation model, while it can be explained by Modified Newtonian Dynamics. In this Letter, we show that the MDAR arises in a ΛCDM cosmology once observed galaxy scaling relations are taken into account. We build semi-empirical models based on ΛCDM haloes, with and without the inclusion of baryonic effects, coupled to empirically motivated structural relations. Our models can reproduce the MDAR: specifically, a mass-dependent density profile for DM haloes can fully account for the observed MDAR shape, while a universal profile shows a discrepancy with the MDAR of dwarf galaxies with M⋆ < 109.5 M⊙, a further indication suggesting the existence of DM cores. Additionally, we reproduce slope and normalization of the baryonic Tully-Fisher relation (BTFR) with 0.17 dex scatter. These results imply that in ΛCDM (i) the MDAR is driven by structural scaling relations of galaxies and DM density profile shapes, and (ii) the baryonic fractions determined by the BTFR are consistent with those inferred from abundance-matching studies.

  1. Dynamical family properties and dark halo scaling relations of giant elliptical galaxies

    CERN Document Server

    Gerhard, O E; Saglia, R P; Bender, R; Gerhard, Ortwin; Kronawitter, Andi; Bender, Ralf

    2001-01-01

    Based on a uniform dynamical analysis of line-profile shapes for 21 luminous round elliptical galaxies, we have investigated the dynamical family relations of ellipticals: (i) The circular velocity curves (CVCs) of elliptical galaxies are flat to within ~10% for R>~0.2R_e. (ii) Most ellipticals are moderately radially anisotropic; their dynamical structure is surprisingly uniform. (iii) Elliptical galaxies follow a Tully-Fisher (TF) relation, with v_c^max=300 km/s for an L_B^* galaxy. At given v_c^max, they are ~1 mag fainter in B and appear to have slightly lower baryonic mass than spirals even for maximum M/L_B. (iv) The luminosity dependence of M/L_B is confirmed. The tilt of the Fundamental Plane is not caused by dynamical non-homology, nor only by an increasing dark matter fraction with L. It is, however, consistent with stellar population models based on published metallicities and ages. The main driver is therefore probably metallicity, and a secondary population effect is needed to explain the K-band ...

  2. MASSIV: Mass Assembly Survey with SINFONI in VVDS. IV. Fundamental relations of star-forming galaxies at 1

    CERN Document Server

    Vergani, D; Contini, T; Tasca, L; Tresse, L; Amram, P; Garilli, B; Kissler-Patig, M; Fevre, O Le; Moultaka, J; Paioro, L; Queyrel, J; Lopez-Sanjuan, C

    2012-01-01

    How mass assembly occurs in galaxies and which processes contribute to such activity are some of the main questions highly debated in galaxy formation and evolution theories. This has motivated our survey MASSIV (Mass Assembly Survey with SINFONI in VVDS) of 0.9relations between galaxy size, mass, and internal velocity, and the baryonic Tully-Fisher relation, from a statistically representative sample of star-forming galaxies at 1relations with discs being evenly smaller with cosmic time at fixed stellar mass or velocity, and less massive for a given velocity with respect to the local Universe. This result does not imply...

  3. Cloud Information Content Analysis for EPIC's Oxygen A- and B-band Channels

    Science.gov (United States)

    Davis, A. B.; Sanghavi, S.

    2011-12-01

    The Earth Polychromatic Imaging Camera (EPIC) instrument on the Deep Space Climate Observatory (DSCOVR) will have two molecular oxygen channels: one for the well-known ``A'' band at~764 nm and one for the weaker ``B'' band at 688~nm. In both cases, a channel-integrated relative measurement of absorption is possible using an ``in-band'' channel and a nearby ``reference'' channel. Together, these four observations enable a rudimentary differential optical absorption spectroscopy (DOAS) of O2 in the characteristic retro-reflection geometry of the L1 vantage point. A priori, we thus have at best two new pieces of cloud information to access. EPIC's pixels have 10x10 km2 footprints at nadir (center of the illuminated disk), more as the viewing angle increases away from local zenith. What new information can be learned about clouds from these data on a pixel-by-pixel basis? O2 A-band observations from space have been pioneered with CNES's POLDER, ESA's SCIAMACHY, and JAXA's GOSat. NASA's OCO-2, to be launched in early 2013, will also have A-band capability. POLDER has low spectral and spatial resolutions, but offers multiple viewing directions for every pixel; SCIAMACHY has higher spectral but worse spatial resolution and just one viewing angle. GOSat has very high spectral but rather low spatial resolutions, again with the possibility of dense angular sampling, but no imaging (just one pixel at a time). OCO-2, a narrow swath imager, will have similarly high spectral resolution and reasonably high ( ˜2~km) spatial resolution. Of these four LEO missions, two are focused on CO2 DOAS, with O2 being assayed operationally only to deliver it in ppm's. POLDER and SCIAMACHY however have official cloud products based on A-band measurements. They contain, at the least, an estimate of cloud top height and, at the most, that plus an estimate of cloud pressure thickness. Cloud optical depth and effective particle size are derived from other spectral data, including continuum values

  4. Timescale Stretch Parameterization of Type Ia Supernova B-band Light Curves

    CERN Document Server

    Goldhaber, Gerson; Kim, A; Aldering, G; Astier, Pierre; Conley, A; Deustua, S E; Ellis, R; Fabbro, S; Fruchter, A S; Goobar, A; Hook, I; Irwin, M; Kim, M; Knop, R A; Lidman, C E; McMahon, R; Nugent, P; Pain, R; Panagia, N; Pennypacker, C R; Perlmutter, S; Ruiz-Lapuente, P; Schaefer, B; Walton, N A; York, T; Project, The Supernova Cosmology

    2001-01-01

    R-band intensity measurements along the light curve of Type Ia supernovae discovered by the Supernova Cosmology Project (SCP) are fitted in brightness to templates allowing a free parameter the time-axis width factor w = s(1+z). The data points are then individually aligned in the time-axis, normalized and K-corrected back to the rest frame, after which the nearly 1300 normalized intensity measurements are found to lie on a well-determined common rest-frame B-band curve which we call the ``composite curve''. The same procedure is applied to 18 low-redshift Calan/Tololo SNe with z < 0.11; these nearly 300 B-band photometry points are found to lie on the composite curve equally well. The SCP search technique produces several measurements before maximum light for each supernova. We demonstrate that the linear stretch factor, s, which parameterizes the light-curve timescale appears independent of z,and applies equally well to the declining and rising parts of the light curve. In fact, the B-band template that ...

  5. Fundamental mass-spin-morphology relation of spiral galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Obreschkow, D. [International Centre for Radio Astronomy Research (ICRAR), M468, University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009 (Australia); Glazebrook, K. [ARC Centre of Excellence for All-sky Astrophysics (CAASTRO) (Australia)

    2014-03-20

    This work presents high-precision measurements of the specific baryon angular momentum j {sub b} contained in stars, atomic gas, and molecular gas, out to ≳ 10 scale radii, in 16 nearby spiral galaxies of the THINGS sample. The accuracy of these measurements improves on existing studies by an order of magnitude, leading to the discovery of a strong correlation between the baryon mass M {sub b}, j {sub b}, and the bulge mass fraction β, fitted by β=−(0.34±0.03) lg (j{sub b}M{sub b}{sup −1}/[10{sup −7} kpc km s{sup −1} M{sub ⊙}{sup −1}])−(0.04±0.01) on the full sample range of 0 ≤ β ≲ 0.3 and 10{sup 9} M {sub ☉} < M {sub b} < 10{sup 11} M {sub ☉}. The corresponding relation for the stellar quantities M {sub *} and j {sub *} is identical within the uncertainties. These M-j-β relations likely originate from the proportionality between jM {sup –1} and the surface density of the disk that dictates its stability against (pseudo-)bulge formation. Using a cold dark matter model, we can approximately explain classical scaling relations, such as the fundamental plane of spiral galaxies, the Tully-Fisher relation, and the mass-size relation, in terms of the M-j(-β) relation. These results advocate the use of mass and angular momentum as the most fundamental quantities of spiral galaxies.

  6. Towards an interpretation of MOND as a modification of inertia

    CERN Document Server

    Namouni, Fathi

    2015-01-01

    We explore the possibility that Milgrom's Modified Newtonian Dynamics (MOND) is a manifestation of the modification of inertia at small accelerations. Consistent with the Tully-Fisher relation, dynamics in the small acceleration domain may originate from a quartic (cubic) velocity-dependence of energy (momentum) whereas gravitational potentials remain linear with respect to mass. The natural framework for this interpretation is Finsler geometry. The simplest static isotropic Finsler metric of a gravitating mass that incorporates the Tully-Fisher relation at small acceleration is associated with a spacetime interval that is either a homogeneous quartic root of polynomials of local displacements or a simple root of a rational fraction thereof. We determine the low energy gravitational equation and find that Finsler spacetimes that produce a Tully-Fisher relation require that the gravitational potential be modified. For an isolated mass, Newton's potential $Mr^{-1}$ is replaced by $Ma_0\\log (r/r_0)$ where $a_0$ ...

  7. Fingerprints of the hierarchical building up of the structure on the gas kinematics of galaxies

    CERN Document Server

    De Rossi, Maria E; Pedrosa, Susana E

    2012-01-01

    Recent observational and theoretical works have suggested that the Tully-Fisher Relation might be generalised to include dispersion-dominated systems by combining the rotation and dispersion velocity in the definition of the kinematical indicator. Mergers and interactions have been pointed out as responsible of driving turbulent and disordered gas kinematics, which could generate Tully-Fisher Relation outliers. We intend to investigate the gas kinematics of galaxies by using a simulated sample which includes both, gas disc-dominated and spheroid-dominated systems. Cosmological hydrodynamical simulations which include a multiphase model and physically-motivated Supernova feedback were performed in order to follow the evolution of galaxies as they are assembled. Both the baryonic and stellar Tully-Fisher relations for gas disc-dominated systems are tight while, as more dispersion-dominated systems are included, the scatter increases. We found a clear correlation between $\\sigma / V_{\\rm rot}$ and morphology, wi...

  8. Erratum - The many lives of AGN: cooling flows, black holes and the luminosities and colours of galaxies

    OpenAIRE

    Croton, Darren J; Springel, Volker; White, Simon D. M.; De Lucia, G.; Frenk, C.S.; Gao, L.; Jenkins, A.; Kauffmann, G.; Navarro, J.F.; N. Yoshida

    2006-01-01

    In Figure 6 we inadvertently labeled the proxy circular velocity as the virial velocity of the dark matter halo instead of what is actually plotted, the maximum circular velocity of the dark matter halo. The maximum halo circular velocity is a much better estimate of the disk V_c than is V_vir. This confusion influenced the discussion of the Tully-Fisher relation in our paper. In fact, Figure 6 demonstrates that it is possible to simultaneously reproduce both the local Tully-Fisher relation a...

  9. Gravitational lensing by damped Ly-alpha absorbers

    NARCIS (Netherlands)

    Smette, A; Claeskens, JF; Surdej, J

    1997-01-01

    Assuming that (i) damped Ly-alpha absorbers (DLAs) arise in present-day-like spiral galaxies which are immersed in isothermal dark matter halos, (ii) that these galaxies obey the Tully-Fisher sigma/sigma* = (L/L*)(1/alpha TF) and the Holmberg R-L/R* = (L/L*)(alpha H) relations, and (iii) that they f

  10. Polarimetric remote sensing in oxygen A and B bands: sensitivity study and information content analysis for vertical profile of aerosols

    Science.gov (United States)

    Ding, Shouguo; Wang, Jun; Xu, Xiaoguang

    2016-05-01

    Theoretical analysis is conducted to reveal the information content of aerosol vertical profile in space-borne measurements of the backscattered radiance and degree of linear polarization (DOLP) in oxygen (O2) A and B bands. Assuming a quasi-Gaussian shape for aerosol vertical profile characterized by peak height H and half width γ (at half maximum), the Unified Linearized Vector Radiative Transfer Model (UNL-VRTM) is used to simulate the Stokes four-vector elements of upwelling radiation at the top of atmosphere (TOA) and their Jacobians with respect to H and γ. Calculations for different aerosol types and different combinations of H and γ values show that the wide range of gas absorption optical depth in O2 A and B band enables the sensitivity of backscattered DOLP and radiance at TOA to the aerosol layer at different altitudes. Quantitatively, DOLP in O2 A and B bands is found to be more sensitive to H and γ than radiance, especially over the bright surfaces (with large visible reflectance). In many O2 absorption wavelengths, the degree of freedom of signal (DFS) for retrieving H (or γ) generally increases with H (and γ) and can be close to unity in many cases, assuming that the composite uncertainty from surface and aerosol scattering properties as well as measurements is less than 5 %. Further analysis demonstrates that DFS needed for simultaneous retrieval of H and γ can be obtained from a combined use of DOLP measurements at ˜ 10-100 O2 A and B absorption wavelengths (or channels), depending on the specific values of H. The higher the aerosol layer, the fewer number of channels for DOLP measurements in O2 A and B bands are needed for characterizing H and γ. Future hyperspectral measurements of DOLP in O2 A and B bands are needed to continue studying their potential and their combination with radiance and DOLP in atmospheric window channels for retrieving the vertical profiles of aerosols, especially highly scattering aerosols, over land.

  11. Vegetation Red-edge Spectral Modeling for Solar-induced Chlorophyll Fluorescence Retrieval at O2-B Band

    Science.gov (United States)

    Huang, C.; Zhang, L.; Qiao, N.; Zhang, X.; Li, Y.

    2015-12-01

    Remotely sensed solar-induced chlorophyll fluorescence (SIF) has been considered an ideal probe in monitoring global vegetation photosynthesis. However, challenges in accurate estimate of faint SIF (less than 5% of the total reflected radiation in near infrared bands) from the observed apparent reflected radiation greatly limit its wide applications. Currently, the telluric O2-B (~688nm) and O2-A (~761nm) have been proved to be capable of SIF retrieval based on Fraunhofer line depth (FLD) principle. They may still work well even using conventional ground-based commercial spectrometers with typical spectral resolutions of 2~5 nm and high enough signal-to-noise ratio (e.g., the ASD spectrometer). Nevertheless, almost all current FLD based algorithms were mainly developed for O2-A, a few concentrating on the other SIF emission peak in O2-B. One of the critical reasons is that it is very difficult to model the sudden varying reflectance around O2-B band located in the red-edge spectral region (about 680-800 nm). This study investigates a new method by combining the established inverted Gaussian reflectance model (IGM) and FLD principle using diurnal canopy spectra with relative low spectral resolutions of 1 nm (FluorMOD simulations) and 3 nm (measured by ASD spectrometer) respectively. The IGM has been reported to be an objective and good method to characterize the entire vegetation red-edge reflectance. Consequently, the proposed SIF retrieval method (hereinafter called IGMFLD) could exploit all the spectral information along the whole red-edge (680-800 nm) to obtain more reasonable reflectance and fluorescence correction coefficients than traditional FLD methods such as the iFLD. Initial results show that the IGMFLD can better capture the spectrally non-linear characterization of the reflectance in 680-800 nm and thereby yields much more accurate SIFs in O2-B than typical FLD methods, including sFLD, 3FLD and iFLD (see figure 1). Finally, uncertainties and prospect

  12. Spectral line-shapes of oxygen B-band transitions measured with cavity ring-down spectroscopy

    International Nuclear Information System (INIS)

    Results of line-shape measurements of self- and N2-broadened P9 P9 transition of the oxygen B band are presented. Spectra were acquired using the optical frequency comb- assisted Pound-Drever-Hall-locked frequency-stabilized cavity ring-down spectrometer (PDH- locked FS-CRDS). In the line-shape analysis the line narrowing described by Dicke narrowing or/and the speed dependence of collisional broadening were taken into account. The multispectrum fitting technique was used to minimize numerical correlations between line-shape parameters. Collisional broadening and shifting coefficients are reported with sub-percent uncertainties. Influence of the spectral line-shape model used in data analysis on determined line intensities and collisional broadening is discussed

  13. Kinematics of M51-type interacting galaxies

    CERN Document Server

    Gunthardt, G; Aguero, M P

    2016-01-01

    We present a kinematic catalogue for 21 M51-type galaxies. It consists of radial velocity distributions both from main and satellite components, along different position angles, which we obtained from long-slit spectroscopy. We detect deviations from circular motion in most of the main galaxies of each pair, due to the gravitational perturbation produced by the satellite galaxy. However somesystems do not show significant distortions in their radial velocity curves. We found some differences between the directions of photometric and kinematic major axes in main galaxies with a bar subsystem. The Tully-Fisher relation in the B-band and Ks-band for the present sample of M51-type systems is flatter when compared with isolated galaxies. Using the radial velocity data set, we built a synthetic normalized radial velocity distribution, as a reference for future modeling of these peculiar systems. The relative position angles between main galaxy major axis and companion location, as well as the velocity difference am...

  14. Dynamical Family Properties and Dark Halo Scaling Relations of Giant Elliptical Galaxies

    Science.gov (United States)

    Gerhard, Ortwin; Kronawitter, Andi; Saglia, R. P.; Bender, Ralf

    2001-04-01

    Based on a uniform dynamical analysis of the line-profile shapes of 21 mostly luminous, slowly rotating, and nearly round elliptical galaxies, we have investigated the dynamical family relations and dark halo properties of ellipticals. Our results include: (i) The circular velocity curves (CVCs) of elliptical galaxies are flat to within ~=10% for R>~0.2Re. (ii) Most ellipticals are moderately radially anisotropic; their dynamical structure is surprisingly uniform. (iii) Elliptical galaxies follow a Tully-Fisher (TF) relation with marginally shallower slope than spiral galaxies, and vmaxc~=300 km s-1 for an L*B galaxy. At given circular velocity, they are ~1 mag fainter in B and ~0.6 mag in R and appear to have slightly lower baryonic mass than spirals, even for the maximum M/LB allowed by the kinematics. (iv) The luminosity dependence of M/LB indicated by the tilt of the fundamental plane (FP) is confirmed. The tilt of the FP is not caused by dynamical or photometric nonhomology, although the latter might influence the slope of M/L versus L. It can also not be due only to an increasing dark matter fraction with L for the range of IMF currently discussed. It is, however, consistent with stellar population models based on published metallicities and ages. The main driver is therefore probably metallicity, and a secondary population effect is needed to explain the K-band tilt. (v) These results make it likely that elliptical galaxies have nearly maximal M/LB (minimal halos). (vi) Despite the uniformly flat CVCs, there is a spread in the luminous to dark matter ratio and in cumulative M/LB(r). Some galaxies have no indication for dark matter within 2Re, whereas for others we obtain local M/LB-values of 20-30 at 2Re. (vii) In models with maximum stellar mass, the dark matter contributes ~10%-40% of the mass within Re. Equal interior mass of dark and luminous matter is predicted at ~2-4Re. (viii) Even in these maximum stellar mass models, the halo core densities and

  15. Kinematic Evolution of Field and Cluster Spiral Galaxies

    CERN Document Server

    Ziegler, Bodo

    2014-01-01

    We investigate the evolution of the Tully-Fisher relation out to z=1 with 137 emission-line galaxies in the field that display a regular rotation curve. They follow a linear trend with lookback time being on average brighter by 1.1Bmag and 60% smaller at z=1. For a subsample of 48 objects with very regular gas kinematics and stellar structure we derive a TF scatter of 1.15mag, which is two times larger than local samples exhibit. This is probably due to modest variations in their star formation history and chemical enrichment. In another study of 96 members of Abell 901/902 at z=0.17 and 86 field galaxies with similar redshifts we find a difference in the TFR of 0.42mag in the B-band but no significant difference in stellar mass. Comparing specifically red spirals with blue ones in the cluster, the former are fainter on average by 0.35Bmag and have 15% lower stellar masses. This is probably due to star formation quenching caused by ram-pressure in the cluster environment. Evidence for this scenario comes from...

  16. Evolution of the gas kinematics of galaxies in cosmological simulations

    CERN Document Server

    De Rossi, Maria E

    2013-01-01

    We studied the evolution of the gas kinematics of galaxies by performing hydrodynamical simulations in a cosmological scenario. We paid special attention to the origin of the scatter of the Tully-Fisher relation and the features which could be associated with mergers and interactions. We extended the study by De Rossi et al. (2010) and analysed their whole simulated sample which includes both, gas disc-dominated and spheroid-dominated systems. We found that mergers and interactions can affect the rotation curves directly or indirectly inducing a scatter in the Tully-Fisher Relation larger than the simulated evolution since z=3. In agreement with previous works, kinematical indicators which combine the rotation velocity and dispersion velocity in their definitions lead to a tighter relation. In addition, when we estimated the rotation velocity at the maximum of the rotation curve, we obtained the best proxy for the potential well regardless of morphology.

  17. Erratum - The many lives of AGN: cooling flows, black holes and the luminosities and colours of galaxies

    CERN Document Server

    Croton, D J; White, S D M; De Lucia, G; Frenk, C S; Gao, L; Jenkins, A; Kauffmann, G; Navarro, J F; Yoshida, N; Croton, Darren J.; Springel, Volker; White, Simon D. M.

    2006-01-01

    In Figure 6 we inadvertently labeled the proxy circular velocity as the virial velocity of the dark matter halo instead of what is actually plotted, the maximum circular velocity of the dark matter halo. The maximum halo circular velocity is a much better estimate of the disk V_c than is V_vir. This confusion influenced the discussion of the Tully-Fisher relation in our paper. In fact, Figure 6 demonstrates that it is possible to simultaneously reproduce both the local Tully-Fisher relation and luminosity function using semi-analytic techniques applied to the standard LCDM cosmology, thus contradicting previous studies of this issue and our own discussion in Section 3.6.

  18. Retrieval of the optical depth and vertical distribution of particulate scatterers in the atmosphere using O2 A- and B-band SCIAMACHY observations over Kanpur: a case study

    Directory of Open Access Journals (Sweden)

    U. Platt

    2012-05-01

    Full Text Available Due to the well-defined vertical profile of O2 in the atmosphere, the strong A-band (757–774 nm has long been used to estimate vertical distributions of aerosol/cloud from space. We extend this approach to include part of the O2 B-band (684–688 nm as well. SCIAMACHY onboard ENVISAT is the first instrument to provide spectral data at moderate resolution (0.2–1.5 nm in the UV/VIS/NIR including both the O2 A- and B-bands. Using SCIAMACHY specifications, we make combined use of these bands in an optimal estimation algorithm. Theoretical studies show that our algorithm is applicable both over bright and dark surfaces for the retrieval of a lognormal approximation of the vertical profile of particulate matter, in addition to its optical thickness. Synthetic studies and information content analyses prove that such a combined use provides additional information on the vertical distribution of atmospheric scatterers, attributable to differences in the absorption strengths of the two bands and their underlying surface albedos. Due to the high computational cost of the retrieval, we restrict application to real data to a case study over Kanpur through the year 2003. Comparison with AERONET data shows a commonly observed seasonal pattern of haziness, manifesting a correlation coefficient of r = 0.92 for non-monsoon monthly mean AOTs. The retrieved particulate optical thickness is found to be anti-correlated with the relative contrast of the Lambertian equivalent reflectivity (LER at 682 nm and 755 nm by a coefficient of 0.788, confirming the hypothesis made in Sanghavi et al. (2010. Our case study demonstrates a stable physics-based retrieval of particulate matter using only SCIAMACHY data. The feasibility of our approach is enhanced by the information provided by measurements around the O2 B-band in addition to the A-band. Nonetheless, operational application to SCIAMACHY data remains challenged by radiometric uncertainties, yielding simultaneous

  19. Update on HI data collection from GBT, Parkes and Arecibo telescopes for the Cosmic Flows project

    CERN Document Server

    Courtois, Helene M

    2014-01-01

    Cosmic Flows is an international multi-element project with the goal to map motions of galaxies in the Local Universe. Kinematic information from observations in the radio HI line and photometry at optical or near-infrared bands are acquired to derive the large majority of distances that are obtained through the luminosity-linewidth or Tully-Fisher relation. This paper gathers additional observational radio data, frequently unpublished, retrieved from the archives of Green Bank, Parkes and Arecibo telescopes. Extracted HI profiles are consistently processed to produce linewidth measurements. Our current "All-Digital HI Catalog" contains a total of 20,343 HI spectra for 17,738 galaxies with 14,802 galaxies with accurate linewidth measurement useful for Tully-Fisher galaxy distances. This addition of 4,117 new measurements represents an augmentation of 34\\% compared to our last release.

  20. Update on H I data collection from Green Bank, Parkes and Arecibo telescopes for the Cosmic Flows project

    Science.gov (United States)

    Courtois, Hélène M.; Tully, R. Brent

    2015-02-01

    Cosmic Flows is an international multi-element project with the goal to map motions of galaxies in the local Universe. Kinematic information from observations in the radio H I line and photometry at optical or near-infrared bands are acquired to derive the large majority of distances that are obtained through the luminosity-linewidth or Tully-Fisher relation. This paper gathers additional observational radio data, frequently unpublished, retrieved from the archives of Green Bank, Parkes and Arecibo telescopes. Extracted H I profiles are consistently processed to produce linewidth measurements. Our current `All-Digital H I Catalog' contains a total of 20 343 H I spectra for 17 738 galaxies with 14 802 galaxies with accurate linewidth measurement useful for Tully-Fisher galaxy distances. This addition of 4117 new measurements represents an augmentation of 34 per cent compared to our last release.

  1. The MOND Fundamental Plane

    OpenAIRE

    Cardone, V. F.; Angus, G.; Diaferio, A.; Tortora, C.; Molinaro, R.

    2010-01-01

    Modified Newtonian Dynamics (MOND) has been shown to be able to fit spiral galaxy rotation curves as well as giving a theoretical foundation for empirically determined scaling relations, such as the Tully - Fisher law, without the need for a dark matter halo. As a complementary analysis, one should investigate whether MOND can also reproduce the dynamics of early - type galaxies (ETGs) without dark matter. As a first step, we here show that MOND can indeed fit the observed central velocity di...

  2. Nonlocal Metric Realizations of MOND

    OpenAIRE

    Woodard, R. P.

    2014-01-01

    I discuss relativistic extensions of MOND in which the metric couples normally to matter. I argue that MOND might be a residual effect from the vacuum polarization of infrared gravitons produced during primordial inflation. If so, MOND corrections to the gravitational field equations would be nonlocal. Nonocality also results when one constructs metric field equations which reproduce the Tully-Fisher relation, along with sufficient weak lensing. I give the full field equations for the simples...

  3. Alternative proposal to modified Newtonian dynamics

    OpenAIRE

    Romero, Juan M.; Zamora, Adolfo

    2006-01-01

    From a study of conserved quantities of the so-called Modified Newtonian Dynamics (MOND) we propose an alternative to this theory. We show that this proposal is consistent with the Tully-Fisher law, has conserved quantities whose Newtonian limit are the energy and angular momentum, and can be useful to explain cosmic acceleration. The dynamics obtained suggests that, when acceleration is very small, time depends on acceleration. This result is analogous to that of special relativity where tim...

  4. Alternative proposal to modified Newtonian dynamics

    International Nuclear Information System (INIS)

    From a study of conserved quantities of the so-called modified Newtonian dynamics we propose an alternative to this theory. We show that this proposal is consistent with the Tully-Fisher law, has conserved quantities whose Newtonian limit are the energy and angular momentum, and can be useful to explain cosmic acceleration. The dynamics obtained suggests that, when acceleration is very small, time depends on acceleration. This result is analogous to that of special relativity where time depends on velocity

  5. The Hubble Web: The Dark Matter Problem and Cosmic Strings

    OpenAIRE

    Alexander, Stephon

    2007-01-01

    I propose a reinterpretation of cosmic dark matter in which a rigid network of cosmic strings formed at the end of inflation. The cosmic strings fulfill three functions: At recombination they provide an accretion mechanism for virializing baryonic and warm dark matter into disks. These cosmic strings survive as configurations which thread spiral and elliptical galaxies leading to the observed flatness of rotation curves and the Tully-Fisher relation. We find a relationship between the rotatio...

  6. Effect of wzx (rfbX) Mutations on A-Band and B-Band Lipopolysaccharide Biosynthesis in Pseudomonas aeruginosa O5

    OpenAIRE

    Burrows, Lori L.; Lam, Joseph S.

    1999-01-01

    The wbp cluster of Pseudomonas aeruginosa O5 encodes a number of proteins involved in biosynthesis of the heteropolymeric and Wzy-dependent B-band O antigen, including Wzy, the O-antigen polymerase, and Wzz, the regulator of O-antigen chain length. A gene (formerly wbpF), contiguous with wzy in the wbp cluster, is predicted to encode a highly hydrophobic protein with multiple membrane-spanning domains. This secondary structure is consistent with that of Wzx (RfbX), the putative O-antigen unit...

  7. 2MTF III. HI 21cm observations of 1194 spiral galaxies with the Green Bank Telescope

    CERN Document Server

    Masters, Karen L; Hong, Tao; Jarrett, T H; Koribalski, Baerbel S; Macri, Lucas; Springob, Christopher M; Staveley-Smith, Lister

    2014-01-01

    We present HI 21cm observations of 1194 galaxies out to a redshift of 10,000 km/s selected as inclined spirals (i>60deg) from the 2MASS Redshift Survey. These observations were carried out at the National Radio Astronomy Observatory Robert C. Byrd Green Bank Telescope (GBT). This observing program is part of the 2MASS Tully-Fisher (2MTF) survey. This project will combine HI widths from these GBT observations with those from further dedicated observing at the Parkes Telescope, from the ALFALFA survey at Arecibo, and S/N>10 and spectral resolution, v_res < 10km/s published widths from a variety of telescopes. We will use these HI widths along with 2MASS photometry to estimate Tully-Fisher distances to nearby spirals and investigate the peculiar velocity field of the local Universe. In this paper we report on detections of neutral hydrogen in emission in 727 galaxies, and measure good signal-to-noise and symmetric HI global profiles suitable for use in the Tully-Fisher relation in 484.

  8. The evolution of the galaxy B-band rest-frame morphology to z~2: new clues from the K20/GOODS sample

    CERN Document Server

    Cassata, P; Franceschini, A; Daddi, E; Pignatelli, E; Fasano, G; Rodighiero, G; Pozzetti, L; Mignoli, M; Renzini, A

    2004-01-01

    We present a detailed analysis of the evolution of the rest-frame B-band morphology of K-selected galaxies with 0 < z < 2.5. This work is based on the K20 spectroscopic sample (Ks<20) located within the Chandra Deep Field South area, coupled with the public deep GOODS HST+ACSmulti-band optical imaging available in that field. Thanks to the spectroscopic completeness of this catalog reaching 94%, we can compare the morphological and spectroscopic properties of galaxies with unprecedented detail. Our morphological analysis includes visual inspection and automatic procedures using both parametric (e.g. the Sersic indices treated by the GALFIT and GASPHOT packages) and non-parametric (the Concentration, Asymmetry and clumpineSs, CAS) methods. Our analysis classifies the K20 galaxies as: 60/300 (20%, class 1) normal ellipticals/S0; 14/300 (4%, class 2) perturbed or peculiar ellipticals; 80/300 (27%, class 3) normal spirals; 48/300 (16%, class 4) perturbed or actively star-forming spirals; 98/300 (33%, cla...

  9. Towards an interpretation of MOND as a modification of inertia

    Science.gov (United States)

    Namouni, Fathi

    2015-09-01

    We explore the possibility that Milgrom's modified Newtonian dynamics (MOND) is a manifestation of the modification of inertia at small accelerations. Consistent with the Tully-Fisher relation, dynamics in the small acceleration domain may originate from a quartic (cubic) velocity dependence of energy (momentum) whereas gravitational potentials remain linear with respect to mass. The natural framework for this interpretation is Finsler geometry. The simplest static isotropic Finsler metric of a gravitating mass that incorporates the Tully-Fisher relation at small acceleration is associated with a space-time interval that is either a homogeneous quartic root of polynomials of local displacements or a simple root of a rational fraction thereof. We determine the weak field gravitational equation and find that Finsler space-times that produce a Tully-Fisher relation require that the gravitational potential be modified. For an isolated mass, Newton's potential Mr-1 is replaced by Ma0log (r/r0), where a0 is MOND's acceleration scale and r0 is a yet undetermined distance scale. Orbital energy is linear with respect to mass but angular momentum is proportional to M3/4. Asymptotic light deflection resulting from time curvature is similar to that of a singular isothermal sphere implying that space curvature must be the main source of deflection in static Finsler space-times possibly through the presence of the distance scale r0 that appears in the asymptotic form of the gravitational potential. The quartic nature of the Finsler metric hints at the existence of an underlying area metric that describes the effective structure of space-time.

  10. THE PHOTOMETRIC AND KINEMATIC STRUCTURE OF FACE-ON DISK GALAXIES. III. KINEMATIC INCLINATIONS FROM H{alpha} VELOCITY FIELDS

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, David R. [NRC Herzberg Institute of Astrophysics, 5071 W Saanich Road, Victoria, BC V9E 2E7 (Canada); Bershady, Matthew A., E-mail: david.andersen@nrc-cnrc.gc.ca, E-mail: mab@astro.wisc.edu [Department of Astronomy, University of Wisconsin, 475 N Charter Street, Madison, WI 53706 (United States)

    2013-05-01

    Using the integral field unit DensePak on the WIYN 3.5 m telescope we have obtained H{alpha} velocity fields of 39 nearly face-on disks at echelle resolutions. High-quality, uniform kinematic data and a new modeling technique enabled us to derive accurate and precise kinematic inclinations with mean i{sub kin} = 23 Degree-Sign for 90% of these galaxies. Modeling the kinematic data as single, inclined disks in circular rotation improves upon the traditional tilted-ring method. We measure kinematic inclinations with a precision in sin i of 25% at 20 Degree-Sign and 6% at 30 Degree-Sign . Kinematic inclinations are consistent with photometric and inverse Tully-Fisher inclinations when the sample is culled of galaxies with kinematic asymmetries, for which we give two specific prescriptions. Kinematic inclinations can therefore be used in statistical ''face-on'' Tully-Fisher studies. A weighted combination of multiple, independent inclination measurements yield the most precise and accurate inclination. Combining inverse Tully-Fisher inclinations with kinematic inclinations yields joint probability inclinations with a precision in sin i of 10% at 15 Degree-Sign and 5% at 30 Degree-Sign . This level of precision makes accurate mass decompositions of galaxies possible even at low inclination. We find scaling relations between rotation speed and disk-scale length identical to results from more inclined samples. We also observe the trend of more steeply rising rotation curves with increased rotation speed and light concentration. This trend appears to be uncorrelated with disk surface brightness.

  11. A new estimator of the deceleration parameter from galaxy rotation curves

    OpenAIRE

    van Putten, Maurice H. P. M.

    2016-01-01

    The nature of dark energy may be probed by the derivative $Q=\\left.dq(z)/dz\\right|_0$ at redshift $z=0$ of the deceleration parameter $q(z)$. It is probably static if $Q2.5$, supporting $\\Lambda$CDM or, respectively, $\\Lambda=(1-q)H^2$, where $H$ denotes the Hubble parameter. We derive $q=1-\\left(4\\pi a_0/cH\\right)^{2}$, enabling a determination of $q(z)$ by measurement of Milgrom's parameter $a_0(z)$ in galaxy rotation curves, equivalent to the coefficient $A$ in the Tully-Fisher relation $V...

  12. Kinematic Evolution of Field and Cluster Spiral Galaxies

    OpenAIRE

    Ziegler, Bodo; Boehm, Asmus

    2014-01-01

    We investigate the evolution of the Tully-Fisher relation out to z=1 with 137 emission-line galaxies in the field that display a regular rotation curve. They follow a linear trend with lookback time being on average brighter by 1.1Bmag and 60% smaller at z=1. For a subsample of 48 objects with very regular gas kinematics and stellar structure we derive a TF scatter of 1.15mag, which is two times larger than local samples exhibit. This is probably due to modest variations in their star formati...

  13. The Hubble Web: The Dark Matter Problem and Cosmic Strings

    International Nuclear Information System (INIS)

    I propose a reinterpretation of cosmic dark matter in which a rigid network of cosmic strings formed at the end of inflation. The cosmic strings fulfill three functions: At recombination they provide an accretion mechanism for virializing baryonic and warm dark matter into disks. These cosmic strings survive as configurations which thread spiral and elliptical galaxies leading to the observed flatness of rotation curves and the Tully-Fisher relation. We find a relationship between the rotational velocity of the galaxy and the string tension and discuss the testability of this model.

  14. Kinematic studies of disk galaxies inside and around the Abell 901/902 cluster system

    International Nuclear Information System (INIS)

    This thesis examines the region around the Abell 901/902 multiple cluster system. It is located at a redshift of z⁓0.165, which corresponds to a look-back time of around two billion years. The multiple cluster system comprises four subclusters, but it also includes infalling groups and further filaments. Exploiting multi-object slit spectra and galaxy rotation curves we investigate the dynamics of the multiple cluster system as well as the kinematics of our spectroscopic target galaxies. We compare the field with the cluster population and particularly investigate dusty red galaxies, a galaxy population with reduced star-formation rates compared to normal spiral galaxies. In the field environment galaxies with large morphological asymmetries have also more distorted rotation curves. Tidal interactions most probably are responsible for this trend. In the cluster environment, however, we find a significant fraction of galaxies with smooth stellar disks but highly disturbed kinematics. The effects of ram-pressure stripping, disturbing the gas and stripping part of its reservoir but not affecting the stars, are the best explanation for this finding. At a given mass cluster galaxies are fainter in the B-band than field galaxies. This might be due to environmental effects. We find enhanced kinematic distortions and a larger scatter in the luminosity-rotation velocity (Tully-Fisher) relation for galaxies residing closer to the cluster core. Depending on the gas content of a galaxy, an enhancement or suppression of star-formation rates e.g. due to ram pressure explains this trend. The cluster population of dusty red galaxies seems to be particularly influenced by ram-pressure stripping. We measure a reduced gas extent, higher bulge-to-total ratios and lower B-band luminosities (at given mass) for this galaxy type. This fits into a transformation scenario where dusty red galaxies are an intermediate phase and during which field spiral galaxies fall into a cluster

  15. The Modelling of Feedback Processes in Cosmological Simulations of Disk Galaxy Formation

    CERN Document Server

    Piontek, Franziska

    2009-01-01

    We present a systematic study of stellar feedback processes in simulations of disk galaxy formation. Using a dark matter halo with properties similar to the ones for the Milky Way's stellar halo, we perform a comparison of different methods of distributing energy related to feedback processes to the surrounding gas. A most promising standard model is applied to halos spanning a range of masses in order to compare the results to disk galaxy scaling relations. With few exceptions we find little or no angular momentum deficiency for our galaxies and a good agreement with the angular momentum-size relation. Our galaxies are in good agreement with the baryonic Tully-Fisher relation and the slope of the photometric Tully-Fisher relation is reproduced. We find a zero-point offset of 0.7 to 1 magnitudes, depending on the employed IMF. We also study our standard feedback model in combination with additional physical processes like a UV background, kinetic feedback, a delayed energy deposition as expected for type Ia s...

  16. VizieR Online Data Catalog: Surface photometry of GHASP galaxies (Barbosa+, 2015)

    Science.gov (United States)

    Barbosa, C. E.; Mendes de Oliveira, C.; Amram, P.; Ferrari, F.; Russeil, D.; Epinat, B.; Perret, V.; Adami, C.; Marcelin, M.

    2016-04-01

    Our data set is constructed using new Rc-band observations taken at the Observatoire de Haute-Provence, supplemented with Sloan Digital Sky Survey archival data, obtained with the purpose of deriving homogeneous photometric profiles and parameters. Our results include Rc-band surface brightness profiles for 170 galaxies and ugriz profiles for 108 of these objects. We catalogue several parameters of general interest for further reference, such as total magnitude, effective radius and isophotal parameters (magnitude, position angle, ellipticity and inclination). We also perform a structural decomposition of the surface brightness profiles using a multi-component method to separate discs from bulges and bars, and to observe the main scaling relations involving luminosities, sizes and maximum velocities. We determine the Rc-band Tully-Fisher relation using maximum velocities derived solely from Hα rotation curves for a sample of 80 galaxies, resulting in a slope of -8.1+/-0.5, zero-point of -3.0+/-1.0 and an estimated intrinsic scatter of 0.28+/-0.07. We note that, unlike the Tully-Fisher relation in the near-infrared derived for the same sample, no change in the slope of the relation is seen at the low-mass end (for galaxies with Vmaxlaw while the near-infrared has two), may be caused by differences in the stellar mass-to-light ratio for galaxies with Vmaxfiles).

  17. The Arecibo Galaxy Environment Survey VI : The Virgo Cluster (II)

    CERN Document Server

    Taylor, R; Auld, R; Minchin, R F; Smith, R

    2012-01-01

    We present 21 cm observations of a 5 x degree region in the Virgo cluster, obtained as part of the Arecibo Galaxy Environment Survey. 13 cluster members are detected, together with 36 objects in the background. We compare and contrast the results from this area with a larger 10 x degree region. We combine the two data sets to produce an HI mass function, which shows a higher detection rate at low masses (but finds fewer massive galaxies) than less sensitive wider-area surveys, such as ALFALFA. We find that the HI-detected galaxies are distributed differently to the non-detections, both spatially and in velocity, providing further evidence that the cluster is still assembling. We use the Tully-Fisher relation to examine the possibility of morphological evolution. We find that highly deficient galaxies, as well as some early-type galaxies, have much lower velocity widths than the Tully-Fisher relation predicts, indicating gas loss via ram pressure stripping. We also find that HI detections without optical count...

  18. 2MTF V. Cosmography, Beta, and the residual bulk flow

    CERN Document Server

    Springob, Christopher M; Staveley-Smith, Lister; Masters, Karen L; Macri, Lucas M; Koribalski, Baerbel S; Jones, D Heath; Jarrett, Tom H; Magoulas, Christina; Erdogdu, Pirin

    2015-01-01

    Using the Tully-Fisher relation, we derive peculiar velocities for the 2MASS Tully-Fisher Survey and describe the velocity field of the nearby Universe. We use adaptive kernel smoothing to map the velocity field, and compare it to reconstructions based on the redshift space galaxy distributions of the 2MASS Redshift Survey (2MRS) and the IRAS Point Source Catalog Redshift Survey (PSCz). With a standard $\\chi^2$ minimization fit to the models, we find that the PSCz model provides a better fit to the 2MTF velocity field data than does the 2MRS model, and provides a value of $\\beta$ in greater agreement with literature values. However, when we subtract away the monopole deviation in the velocity zeropoint between data and model, the 2MRS model also produces a value of $\\beta$ in agreement with literature values. We also calculate the `residual bulk flow': the component of the bulk flow not accounted for by the models. This is $\\sim 250$ km/s when performing the standard fit, but drops to $\\sim 150$ km/s for both...

  19. Galaxy peculiar velocities in the Zone of Avoidance

    CERN Document Server

    Said, K; Jarrett, T H

    2014-01-01

    Dust extinction and stellar confusion of the Milky Way hinder the detection of galaxies at low Galactic latitude, creating the so-called Zone of Avoidance (ZoA). This has hampered our understanding of the local dynamics, cosmic flow fields and the origin of the Cosmic Microwave Background dipole. The ZoA ($|b| \\le 5^\\circ$) is also excluded from the "whole-sky" Two Micron All-Sky Survey (2MASS) Redshift Survey (2MRS) and 2MASS Tully-Fisher Survey (2MTF). The latter aims to provide distances and peculiar velocities for all bright inclined 2MASS galaxies with $K_s^o$ $\\leq 11\\hbox{$.\\!\\!^{\\rm m}$}25$. Correspondingly, knowledge about the density distribution in the ZoA remains limited to statistical interpolations. To improve on this bias we pursued two different surveys to fill in the southern and northern ZoA. These data will allow a direct measurement of galaxy peculiar velocities. In this paper we will present a newly derived optimized Tully-Fisher (TF) relation that allow accurate measures of galaxy distan...

  20. The Arecibo Galaxy Environment Survey: Observations towards the NGC 7817/7798 Galaxy Pair

    Science.gov (United States)

    Harrison, Amanda; Robert Minchin

    2016-01-01

    The Arecibo Galaxy Environment Survey (AGES) examines the environment of neutral hydrogen gas in the interstellar medium. AGES uses the 305m Arecibo Radio Telescope and the Arecibo L-Band Feed Array to create a deep field neutral hydrogen survey which we used to detect galaxies in an area five square degrees around the galaxy pair NGC 7817/7798. By finding and investigating hydrogen rich galaxies we hope to gain a better understanding of how the environment affects galaxy evolution. H1 line profiles were made for the detected H1 emission and ten galaxies which had the characteristic double-horned feature were found. NGC 7798 was not detected, but NGC 7817 and the other galaxies were cross-identified in NASA/IPAC Extragalactic Database as well as in Sloan Digital Sky Survey to obtain optical data. Out of the ten, two of the sources were uncatalogued. We analyzed the hydrogen spectra and aperture photometry to learn about the characteristics of these galaxies such as their heliocentric velocity, flux, and mass of the neutral hydrogen. Furthermore, we graphed the Tully-Fisher and the Baryonic Tully-Fisher of the ten sources and found that most followed the relation. One that is the biggest outlier is suspected be a galaxy cluster while other outliers may be caused by ram pressure stripping deforming the galaxy.

  1. Relativity

    CERN Document Server

    Einstein, Albert

    2013-01-01

    Time magazine's ""Man of the Century"", Albert Einstein is the founder of modern physics and his theory of relativity is the most important scientific idea of the modern era. In this short book, Einstein explains, using the minimum of mathematical terms, the basic ideas and principles of the theory that has shaped the world we live in today. Unsurpassed by any subsequent books on relativity, this remains the most popular and useful exposition of Einstein's immense contribution to human knowledge.With a new foreword by Derek Raine.

  2. Relativity

    CERN Document Server

    Brewster, Hilary D

    2009-01-01

    The theory of relativity has become a cornerstone of modern physics. Over the course of time it has been scrutinized in a multitude of experiments and has always been verified with high accuracy. The correctness of this theory can no longer be called into question. Right after its discovery by Albert Einstein in 1905, special relativity was only gradually accepted because it made numerous predictions contradicting common sense, fervently castigated by Einstein, and also defied experiment for too long a time. It was only with the advent of particle or high energy physics that matter could be ac

  3. Novel test of modified Newtonian dynamics with gas rich galaxies.

    Science.gov (United States)

    McGaugh, Stacy S

    2011-03-25

    The current cosmological paradigm, the cold dark matter model with a cosmological constant, requires that the mass-energy of the Universe be dominated by invisible components: dark matter and dark energy. An alternative to these dark components is that the law of gravity be modified on the relevant scales. A test of these ideas is provided by the baryonic Tully-Fisher relation (BTFR), an empirical relation between the observed mass of a galaxy and its rotation velocity. Here, I report a test using gas rich galaxies for which both axes of the BTFR can be measured independently of the theories being tested and without the systematic uncertainty in stellar mass that affects the same test with star dominated spirals. The data fall precisely where predicted a priori by the modified Newtonian dynamics. The scatter in the BTFR is attributable entirely to observational uncertainty, consistent with a single effective force law. PMID:21517295

  4. Exploring Large-scale Gravitational Quantization without h-bar in Planetary Systems, Galaxies, and the Universe

    CERN Document Server

    Preston, H G; Preston, Howard G.; Potter, Franklin

    2003-01-01

    We explore a theory of large-scale gravitational quantization, using the general relativistic Hamilton-Jacobi equation to create quantization conditions via a new scalar wave equation dependent upon the total mass and the total vector angular momentum only. Instead of h-bar, a local invariant quantity proportional to the total angular momentum dictates the quantization conditions. In the Schwarzschild metric the theory predicts eigenstates with quantized energy per mass and angular momentum per mass. We find excellent agreement to the orbital spacings of the satellites of the Jovian planets and to the planet spacings in the Solar System. For galaxies we derive the baryonic Tully-Fisher relation and the MOND acceleration, so galaxy velocity curves are explained without requiring 'dark matter'. For the universe, we derive a new Hubble relation that accounts for the accelerated expansion with a matter density at about 5% of the critical matter/energy density, with the remainder being large-scale quantization zer...

  5. What do gas-rich galaxies actually tell us about modified Newtonian dynamics?

    Science.gov (United States)

    Foreman, Simon; Scott, Douglas

    2012-04-01

    It has recently been claimed that measurements of the baryonic Tully-Fisher relation (BTFR), a power-law relationship between the observed baryonic masses and outer rotation velocities of galaxies, support the predictions of modified Newtonian dynamics for the slope and scatter in the relation, while challenging the cold dark matter (CDM) paradigm. We investigate these claims, and find that (1) the scatter in the data used to determine the BTFR is in conflict with observational uncertainties on the data, (2) these data do not make strong distinctions regarding the best-fit BTFR parameters, (3) the literature contains a wide variety of measurements of the BTFR, many of which are discrepant with the recent results, and (4) the claimed CDM "prediction" for the BTFR is a gross oversimplification of the complex galaxy-scale physics involved. We conclude that the BTFR is currently untrustworthy as a test of CDM. PMID:22540783

  6. The Shape of Dark Matter Haloes II. The Galactus HI Modelling & Fitting Tool

    CERN Document Server

    Peters, S P C; Allen, R J; Freeman, K C

    2016-01-01

    We present a new HI modelling tool called \\textsc{Galactus}. The program has been designed to perform automated fits of disc-galaxy models to observations. It includes a treatment for the self-absorption of the gas. The software has been released into the public domain. We describe the design philosophy and inner workings of the program. After this, we model the face-on galaxy NGC2403, using both self-absorption and optically thin models, showing that self-absorption occurs even in face-on galaxies. It is shown that the maximum surface brightness plateaus seen in Paper I of this series are indeed signs of self-absorption. The apparent HI mass of an edge-on galaxy can be drastically lower compared to that same galaxy seen face-on. The Tully-Fisher relation is found to be relatively free from self-absorption issues.

  7. Cosmological simulations of dwarf galaxies with cosmic ray feedback

    Science.gov (United States)

    Chen, Jingjing; Bryan, Greg L.; Salem, Munier

    2016-08-01

    We perform zoom-in cosmological simulations of a suite of dwarf galaxies, examining the impact of cosmic rays (CRs) generated by supernovae, including the effect of diffusion. We first look at the effect of varying the uncertain CR parameters by repeatedly simulating a single galaxy. Then we fix the comic ray model and simulate five dwarf systems with virial masses range from 8 to 30 × 1010 M⊙. We find that including CR feedback (with diffusion) consistently leads to disc-dominated systems with relatively flat rotation curves and constant star formation rates. In contrast, our purely thermal feedback case results in a hot stellar system and bursty star formation. The CR simulations very well match the observed baryonic Tully-Fisher relation, but have a lower gas fraction than in real systems. We also find that the dark matter cores of the CR feedback galaxies are cuspy, while the purely thermal feedback case results in a substantial core.

  8. Cosmological Simulations of Dwarf Galaxies with Cosmic Ray Feedback

    CERN Document Server

    Chen, Jingjing; Salem, Munier

    2016-01-01

    We perform zoom-in cosmological simulations of a suite of dwarf galaxies, examining the impact of cosmic-rays generated by supernovae, including the effect of diffusion. We first look at the effect of varying the uncertain cosmic ray parameters by repeatedly simulating a single galaxy. Then we fix the comic ray model and simulate five dwarf systems with virial masses range from 8-30 $\\times 10^{10}$ Msun. We find that including cosmic ray feedback (with diffusion) consistently leads to disk dominated systems with relatively flat rotation curves and constant star formation rates. In contrast, our purely thermal feedback case results in a hot stellar system and bursty star formation. The CR simulations very well match the observed baryonic Tully-Fisher relation, but have a lower gas fraction than in real systems. We also find that the dark matter cores of the CR feedback galaxies are cuspy, while the purely thermal feedback case results in a substantial core.

  9. An Analytic Mathematical Model to Explain the Spiral Structure and Rotation Curve of NGC 3198

    Science.gov (United States)

    Rout, Bruce; Rout, Cameron

    2016-06-01

    An analytical model of galactic morphology is presented. This model presents resolutions to two inter-related parameters of spiral galaxies: one being the flat velocity rotation profile and the other being the spiral morphology of such galaxies. This model is a mathematical transformation dictated by the general theory of relativity applied to rotating polar coordinate systems that conserve the metric. The model shows that the flat velocity rotation profile and spiral shape of certain galaxies are both products of the general theory. Validation of the model is presented by application to 878 rotation curves provided by Salucci, and by comparing the results of a derived distance modulus to those using Cepheid variables, water masers and Tully-Fisher calculations. The model suggests means of determining galactic linear density, mass and angular momentum. We also show that the morphology of NGC 3198 is congruent to the geodesic as observed within a rotating reference frame and that galaxies are gravitationally viscous and self bound.

  10. How the first stars shaped the faintest gas-dominated dwarf galaxies

    CERN Document Server

    Verbeke, Robbert; De Rijcke, Sven

    2015-01-01

    Low-mass dwarf galaxies are very sensitive test-beds for theories of cosmic structure formation since their weak gravitational fields allow the effects of the relevant physical processes to clearly stand out. Up to now, no unified account exists of the sometimes seemingly conflicting properties of the faintest isolated dwarfs in and around the Local Group, such as Leo T and the recently discovered Leo P and Pisces A systems. Using new numerical simulations, we show that this serious challenge to our understanding of galaxy formation can be effectively resolved by taking into account the regulating influence of the ultraviolet radiation of the first population of stars on a dwarf's star formation rate while otherwise staying within the standard cosmological paradigm for structure formation. These simulations produce faint, gas-dominated, star-forming dwarf galaxies that lie on the baryonic Tully-Fisher relation and that successfully reproduce a broad range of chemical, kinematical, and structural observables o...

  11. A new estimator of the deceleration parameter from galaxy rotation curves

    CERN Document Server

    van Putten, Maurice H P M

    2016-01-01

    The nature of dark energy may be probed by the derivative $Q=\\left.dq(z)/dz\\right|_0$ at redshift $z=0$ of the deceleration parameter $q(z)$. It is probably static if $Q2.5$, supporting $\\Lambda$CDM or, respectively, $\\Lambda=(1-q)H^2$, where $H$ denotes the Hubble parameter. We derive $q=1-\\left(4\\pi a_0/cH\\right)^{2}$, enabling a determination of $q(z)$ by measurement of Milgrom's parameter $a_0(z)$ in galaxy rotation curves, equivalent to the coefficient $A$ in the Tully-Fisher relation $V^4_c=AM_b$ between rotation velocity $V_c$ and baryonic mass $M_b$. We infer that dark matter should be extremely light with clustering limited to the size of galaxy clusters. The associated transition radius to non-Newtonian gravity may conceivably be probed in a free fall Cavendish type experiment in space.

  12. Planetary Nebula Spectrograph survey of S0 galaxy kinematics. II. Clues to the origins of S0 galaxies

    CERN Document Server

    Cortesi, A; Coccato, L; Arnaboldi, M; Gerhard, O; Bamford, S; Napolitano, N R; Romanowsky, A J; Douglas, N G; Kuijken, K; Capaccioli, M; Freeman, K C; Saha, K; Chies-Santos, A L

    2013-01-01

    The stellar kinematics of the spheroids and discs of S0 galaxies contain clues to their formation histories. Unfortunately, it is difficult to disentangle the two components and to recover their stellar kinematics in the faint outer parts of the galaxies using conventional absorption line spectroscopy. This paper therefore presents the stellar kinematics of six S0 galaxies derived from observations of planetary nebulae (PNe), obtained using the Planetary Nebula Spectrograph. To separate the kinematics of the two components, we use a maximum-likelihood method that combines the discrete kinematic data with a photometric component decomposition. The results of this analysis reveal that: the discs of S0 galaxies are rotationally supported; however, the amount of random motion in these discs is systematically higher than in comparable spiral galaxies; and the S0s lie around one magnitude below the Tully--Fisher relation for spiral galaxies, while their spheroids lie nearly one magnitude above the Faber--Jackson re...

  13. Dynamics of galaxies and clusters in \\textit{refracted gravity}

    CERN Document Server

    Matsakos, Titos

    2016-01-01

    We investigate the proof of concept and the implications of \\textit{refracted gravity}, a novel modified gravity aimed to solve the discrepancy between the luminous and the dynamical mass of cosmic structures without resorting to dark matter. Inspired by the behavior of electric fields in matter, refracted gravity introduces a gravitational permittivity that depends on the local mass density and modifies the standard Poisson equation. The resulting gravitational field can become more intense than the Newtonian field and can mimic the presence of dark matter. We show that the refracted gravitational field correctly describes (1) the rotation curves and the Tully-Fisher relation of disk galaxies; and (2) the observed temperature profile of the X-ray gas of galaxy clusters. According to these promising results, we conclude that refracted gravity deserves further investigation.

  14. Linear potentials in galaxies and clusters of galaxies

    CERN Document Server

    Mannheim, P D

    1995-01-01

    In a previous paper we presented a typical set of galactic rotation curves associated with the linear gravitational potential of the conformal invariant fourth order theory of gravity which has recently been advanced by Mannheim and Kazanas as a candidate alternative to the standard second order Newton-Einstein theory. Reasonable agreement with data was obtained for four representative galaxies without the need for any non-luminous or dark matter. In this paper we present the associated formalism and compare and contrast the linear potential explanation of the general systematics of galactic rotation curves and the associated Tully-Fisher relation with that of the standard dark matter theory. Additionally, we show that the conformal gravity picture appears to have survived the recent round of microlensing observations unscathed. Finally, we make a first application of the conformal theory to the larger distance scale associated with a cluster of galaxies, with the theory being found to give a reasonable value...

  15. Dissipative dark matter and the rotation curves of dwarf galaxies

    CERN Document Server

    Foot, R

    2015-01-01

    There is ample evidence from rotation curves that dark matter halo's around disk galaxies have nontrivial dynamics. Of particular significance are: a) the cored dark matter profile of disk galaxies, b) correlations of the shape of rotation curves with baryonic properties, and c) the Tully-Fisher relation. Dark matter halo's around disk galaxies may have nontrivial dynamics if dark matter is strongly self interacting and dissipative. Multicomponent hidden sector dark matter featuring a massless `dark photon' (from an unbroken dark $U(1)$ gauge interaction) which kinetically mixes with the ordinary photon provides a concrete example of such dark matter. The kinetic mixing interaction facilitates halo heating by enabling ordinary supernovae to be a source of these `dark photons'. Dark matter halo's can expand and contract in response to the heating and cooling processes, but for a sufficiently isolated halo should have evolved to a steady state or `equilibrium' configuration where heating and cooling rates local...

  16. Young tidal dwarf galaxies cannot be used to probe dark matter in galaxies

    CERN Document Server

    Flores, H; Fouquet, S; Puech, M; Kroupa, P; Yang, Y; Pawlowski, M

    2015-01-01

    The location of dark-matter free, tidal dwarf galaxies (TDGs) in the baryonic Tully Fisher (bTF) diagram has been used to test cosmological scenarios, leading to various and controversial results. Using new high-resolution 3D spectroscopic data, we re-investigate the morpho-kinematics of these galaxies to verify whether or not they can be used for such a purpose. We find that the three observed TDGs are kinematically not virialized and show complex morphologies and kinematics, leading to considerable uncertainties about their intrinsic rotation velocities and their locations on the bTF. Only one TDG can be identify as a (perturbed) rotation disk that it is indeed a sub-component of NGC5291N and that lies at $<$1$\\sigma$ from the local bTF relation. It results that the presently studied TDGs are young, dynamically forming objects, which are not enough virialized to robustly challenge cosmological scenarios.

  17. Large peculiar velocities in the Hydra-Centaurus supercluster

    International Nuclear Information System (INIS)

    Distances from the infrared Tully-Fisher relation have been obtained with the Parkes radio telescope for six clusters of galaxies in the Hydra-Centaurus supercluster. Three of these clusters show significant positive peculiar velocities of order 500 km/s in a comoving reference frame in which the observer is at rest with respect to the cosmic microwave background radiation. The net peculiar velocity of the sample suggests that Hydra-Centaurus tends to share the motion of the Local Group in this reference frame. The data also fit a model in which two mass concentrations, one at Virgo and one just beyond the centroid of the Parkes sample, perturb the Hubble flow. 54 references

  18. Large peculiar velocities in the Hydra-Centaurus supercluster

    Energy Technology Data Exchange (ETDEWEB)

    Bothun, G.D.; Cornell, M.E.; Dawe, J.A.; Dickens, R.J.; Aaronson, M.

    1989-03-01

    Distances from the infrared Tully-Fisher relation have been obtained with the Parkes radio telescope for six clusters of galaxies in the Hydra-Centaurus supercluster. Three of these clusters show significant positive peculiar velocities of order 500 km/s in a comoving reference frame in which the observer is at rest with respect to the cosmic microwave background radiation. The net peculiar velocity of the sample suggests that Hydra-Centaurus tends to share the motion of the Local Group in this reference frame. The data also fit a model in which two mass concentrations, one at Virgo and one just beyond the centroid of the Parkes sample, perturb the Hubble flow. 54 references.

  19. Various Facets of Spacetime Foam

    CERN Document Server

    Ng, Y Jack

    2011-01-01

    Spacetime foam manifests itself in a variety of ways. It has some attributes of a turbulent fluid. It is the source of the holographic principle. Cosmologically it may play a role in explaining why the energy density has the critical value, why dark energy/matter exists, and why the effective dynamical cosmological constant has the value as observed. Astrophysically the physics of spacetime foam helps to elucidate why the critical acceleration in modified Newtonian dynamics has the observed value; and it provides a possible connection between global physics and local galactic dynamics involving the phenomenon of flat rotation curves of galaxies and the observed Tully-Fisher relation. Spacetime foam physics also sheds light on nonlocal gravitational dynamics.

  20. Dark matter or the other dynamics

    Directory of Open Access Journals (Sweden)

    Y. Sobouti

    2005-09-01

    Full Text Available   Allowing the energy of a gravitational field to serve partially as its own source allows gravitating bodies to exhibit stronger fields, as if they were more massive. Depending on degree of compaction of the body, the field could be one to five times larger than the Newtonian field. This is a comfortable range of increase in field strength and may prove to be of convenience in the study of velocity curves of spirals, of velocity dispersions in clusters of galaxies and in interpreting the Tully-Fisher or Faber-Jackson relations in galaxies or systems of galaxies. The revised gravitation admits of superposition principle but only approximately in systems whose components are widely separated. The revised dynamics admits of the equivalence principle in that, the effective force acting on a test particle is derived from a potential, and could be elimhnated in a freely falling frame of reference.

  1. The formation of disks in massive spiral galaxies

    CERN Document Server

    Hammer, F; Flores, H

    2009-01-01

    The flatness of the rotation curve inside spiral galaxies is interpreted as the imprint of a halo of invisible matter. Using the deepest observations of distant galaxies, we have investigated how large disks could have been formed. Observations include spatially resolved kinematics, detailed morphologies and photometry from UV to mid-IR. Six Giga-years ago, half of the present-day spirals had anomalous kinematics and morphologies that considerably affect the scatter of the Tully Fisher relation. All anomalous galaxies can be modelled through gas-rich, major mergers that lead to a rebuilt of a new disk. The spiral-rebuilding scenario is proposed as a new channel to form large disks in present-day spirals and it accounts for all the observed evolutions since the last 6 Giga-years. A large fraction of the star formation is linked to merging events during their whole durations.

  2. The rotation curves of gas and stars

    Science.gov (United States)

    Westfall, Kyle; Bershady, Matthew A.; MaNGA Team

    2016-01-01

    In its first year alone, the SDSS-IV/MaNGA survey has provided kinematic data useful for determining the rotation curves of both the ionized-gas and stellar components for hundreds of disk galaxies. We use these data to study the well-known Tully-Fisher relation in the local Universe, as well as the difference between the ionized-gas and stellar rotation curves in a novel study of asymmetric drift. The physical scenario for the latter is that gas efficiently dissipates energy allowing it to settle toward the circular speed of the galactic potential, whereas the stellar ensemble orbits more slowly because stars are collisionless and retain any non-circular motions accrued over their dynamical history. In disk galaxies with line-of-sight velocity dispersions that are well-measured with MaNGA's moderate spectral resolution, we demonstrate the correlation between asymmetric drift and stellar velocity dispersion, as expected by the dynamical relation between the two via the stellar phase-space distribution function. This correlation is consistent with measurements obtained at higher spectral resolution by the DiskMass Survey, and it allows us to leverage asymmetric drift to provide stellar velocity dispersion estimates that probe well below the instrumental dispersion. These velocity dispersion measurements can then be used to estimate the dynamical mass surface density of the baryon-dominated disk (Bershady et al. 2010, 2011). Thus, by combining our circular-speed data --- which yield a well-defined Tully-Fisher relation that is consistent with literature studies --- and our measurements of asymmetric drift, we discuss the implications for the dark-matter mass fractions of our galaxy sample. Statistically, our results are consistent with previous claims (e.g., Martinsson et al. 2013) that dark matter is a significant, even dominant, mass component within the effective radius of disk galaxies.

  3. Precision Velocity Fields in Spiral Galaxies. I. Noncircular Motions and rms Noise in Disks

    Science.gov (United States)

    Beauvais, Charles; Bothun, G.

    1999-11-01

    Investigation of the symmetry of the major- and minor-axis rotation curves reveals strong evidence of nonconcentric gas orbits with the maximum center shift of ~300 pc. Comparisons between kinematic and photometric structure (e.g., position angles, inclinations, centers) show considerable noise on small scales. Although large-scale averages are in agreement, this noise is a matter of some concern in the application of the Tully-Fisher method to disk galaxies. Moreover, cases of significant misalignment in position angle between the inner and outer disks are seen in two of the sample galaxies and may indicate the transition between luminous and dark-matter-dominated regions (i.e., where the maximum-disk hypothesis begins to fail). The kinematic disk models are used to find the residual velocity fields, and typical residuals are found to be 10-15 km s-1 over regions 0.5-1.5 kpc in diameter. Correlations are shown to exist between the residual velocity fields and both the Hα intensity and the velocity dispersion images. This suggests that kinematic feedback to the gas from star formation is an important source of noncircular motion. However, the relative quiescence of the large-scale velocity field indicates that the effect does not cause a significant deviation from circular symmetry, kinematically indicating that star formation is not a hidden parameter in the Tully-Fisher relation. Finally, the residual velocity fields are examined for signs of noncircular orbits by looking for azimuthal angular harmonics that would be present if disk galaxies are embedded in a triaxial dark matter potential. For our sample we find the ellipticity of the gas orbits to be round. This is consistent with disks being maximal.

  4. Spiral Galaxy Mass Models and the Distance Scale

    Science.gov (United States)

    Palunas, P.; Williams, T. B.

    1993-12-01

    We present mass models for a sample of Freeman Type I spiral galaxies taken from the southern sky Fabry-Perot Tully-Fisher survey(Schommer \\etal 1993, Bothun \\etal 1992). We fit two component, bulge and disk, photometric models directly to I- and R-band images. The bulge model is a series expansion of Gaussians (a Gabor expansion): each Gaussian in the series has a common center, ellipticity and position angle. The position angle is fixed to be the same as that of the disk. We have found that a deVaucouleurs law does not give a good fit to the bulges of many disk galaxies. The disk model is an exponential with the same center as the bulge. Small-scale radial structure is included in the disk mass model by azimuthally averaging the residuals of the analytic fit in annuli with the same ellipticity and position angle of the disk. Fitting to the full 2-d images helps constrain the disk-bulge deconvolution by using the information in the different ellipticities well as the different radial profiles of the disk and bulge. The photometric model is fitted to the rotation curve assuming a maximum disk and constant mass-to-light ratios for disk and bulge components. The small scale structure in the photometric models is found to reproduce the structure in the rotation curve in many galaxies. We find approximately 15 percent rms scatter in the I-band mass-to-light ratios, as well as correlations to the detailed properties of the kinematics indicating that mass-to-light ratios may be useful in reducing the scatter in the Tully-Fisher relation. Bothun, G.D., Schommer, R.A., Williams, T.B., Mould J.R., Huchra, J.P. 1992, Ap.J., 388, 253. Schommer, R.A., Bothun, G.D., Williams, T.B., Mould J.R. 1993, A.J., 105, 97.

  5. The Effects of Dwarfing Genes (Rht-B1b,Rht-D1b,and Rht8) with Different Sensitivity to GA3 on the Coleoptile Length and Plant Height of Wheat

    Institute of Scientific and Technical Information of China (English)

    TANG Na; JIANG Ying; HE Bei-ru; HU Yin-gang

    2009-01-01

    relatively ideal candidate for the wheat improvement since it significantly reduces the plant height of wheat,but has less effect on the coleoptile length.

  6. Does the Amati Relation depend on the Luminosity of the GRB's Host Galaxy?

    Institute of Scientific and Technical Information of China (English)

    Jing Wang; Jing-Song Deng; Yu-Lei Qiu

    2008-01-01

    In order to test the systematics of the Amati relation, 24 long-duration GRBs with available Eγ,iso, and Ep are separated into two subgroups according to the B-band luminosity of their host galaxies. The Amati relations in the two subgroups are found to be in agreement with each other within the uncertainties. Taking into account of the well established luminosity-metallicity relation of galaxies, no strong evolution of the Amati relation with the GRB's environmental metallicity is implied in this study.

  7. Spiral galaxy distance indicators based on near-infrared photometry

    CERN Document Server

    De Grijs, R

    1999-01-01

    We compare two methods of distance determination to spiral galaxies using optical/near-infrared (NIR) observations, the (I-K) versus M_K colour - absolute magnitude (CM) relation and the I and K-band Tully-Fisher relation (TFR). Dust-free colours and NIR absolute magnitudes greatly enhance the usefulness of the NIR CM relation as a distance indicator for moderately to highly inclined_spiral_ galaxies_in the field_ (inclinations between ~ 80 and 90 deg); by avoiding contamination by dust the scatter in the CM relation is significantly reduced, compared to similar galaxy samples published previously. The CM relation can be used to determine distances to field spiral galaxies with M_K > -25.5, to at least M_K ~ -20. Our results, supplemented with previously published observations for which we can - to some degree - control the effects of extinction, are consistent with a universal nature of the CM relation for field spiral galaxies. High-resolution observations done with the Hubble Space Telescope can provide a ...

  8. The Surface Density Profile of the Galactic Disk from the Terminal Velocity Curve

    CERN Document Server

    McGaugh, Stacy S

    2015-01-01

    The mass distribution of the Galactic disk is constructed from the terminal velocity curve and the mass discrepancy-acceleration relation. Mass models numerically quantifying the detailed surface density profiles are tabulated. For $R_0 = 8$ kpc, the models have stellar mass $5 < M_* < 6 \\times 10^{10}$ M$_{\\odot}$, scale length $2.0 \\le R_d \\le 2.9$ kpc, LSR circular velocity $222 \\le \\Theta_0 \\le 233$ km s$^{-1}$, and solar circle stellar surface density $34 \\le \\Sigma_d(R_0) \\le 61$ M$_{\\odot}$ pc$^{-2}$. The present inter-arm location of the solar neighborhood may have a somewhat lower stellar surface density than average for the solar circle. The Milky Way appears to be a normal spiral galaxy that obeys scaling relations like the Tully-Fisher relation, the size-mass relation, and the disk maximality-surface brightness relation. The stellar disk is maximal, and the spiral arms are massive. The bumps and wiggles in the terminal velocity curve correspond to known spiral features (e.g., the Centaurus A...

  9. On the axis ratio of the stellar velocity ellipsoid in disks of spiral galaxies

    CERN Document Server

    Van der Kruit, P C

    1999-01-01

    The spatial distribution of stars in a disk of a galaxy can be described by a radial scale length and a vertical scale height. The ratio of these two scale parameters contains information on the axis ratio of the velocity ellipsoid, i.e. the ratio of the vertical to radial stellar velocity dispersions of the stars, at least at some fiducial distance from the center. The radial velocity dispersion correlates well with the amplitude of the rotation curve and with the disk integrated magnitude, as was found by Bottema (1993). These relations can be understood as the result of the stellar disk being (marginally) stable against local instabilities at all length scales. This is expressed by Toomre's well-known criterion, which relates the sheer in the rotation to a minimum value that the radial stellar velocity dispersion should have for stability for a given surface density. Via the Tully-Fisher (1977) relation, the velocity dispersion then becomes related to the integrated magnitude and hence to the scale length....

  10. Direct Shear Mapping: Prospects for weak lensing studies of individual galaxy-galaxy lensing systems

    CERN Document Server

    de Burgh-Day, Catherine O; Webster, Rachel L; Hopkins, Andrew M

    2015-01-01

    We have investigated, using both a theoretical and an empirical approach, the frequency of low redshift galaxy-galaxy lensing systems in which the signature of weak lensing might be directly detectable. We find good agreement between these two approaches. In order to make a theoretical estimate of the weak lensing shear, $\\gamma$, for each galaxy in a catalogue, we have made an estimate of the asymptotic circular velocity from the stellar mass using three different approaches: from a simulation based relation, from an empirically-derived relation, and using the baryonic Tully-Fisher relation. Using data from the Galaxy and Mass Assembly redshift survey we estimate the frequency of detectable weak lensing at low redshift. We find that to a redshift of $z\\sim 0.6$, the probability of a galaxy being weakly lensed by at least $\\gamma = 0.02$ is $\\sim 0.01$. A scatter in the $M_*-M_h$ relation results in a shift towards higher measured shears for a given population of galaxies. Given this, and the good probability...

  11. Extinction in SC galaxies

    Science.gov (United States)

    Giovanelli, Riccardo; Haynes, Martha P.; Salzer, John J.; Wegner, Gary; da Costa, Luiz N.; Freudling, Wolfram

    1994-06-01

    We analyze the photometric properties of a sample of Sbc-Sc galaxies with known redshifts, single-dish H I profiles, and Charge Coupled Device (CCD) I band images. We derive laws that relate the measured isophotal radius at muI = 23.5, magnitude, scale length, and H I flux to the face-on aspect. We find spiral galaxies to be substantially less transparent than suggested in most previous determinations, but not as opaque as claimed by Valentijn (1990). Regions in the disk farther than two or three scale lengths from the center are close to completely transparent. In addition to statistically derived relations for the inclination dependence of photometric parameters, we present the results of a modeling exercise that utilizes the 'triplex' model of Disney et al. (1989) to obtain upper limits of the disk opacity. Within the framework of that model, and with qualitative consideration of the effects of scattering on extinction, we estimate late spiral disks at I band to have central optical depths tauI(0) less than 5 and dust absorbing layers with scale heights on the order of half that of the stellar component or less. We discuss our results in light of previous determinations of internal extinction relations and point out the substantial impact of internal extinction on the scatter of the Tully-Fisher relation. We also find that the visual diameters by which large catalogs are constructed (UGC, ESO-Uppsala) are nearly proportional to face-on isophotal diameters.

  12. The stellar mass function and efficiency of galaxy formation with a varying initial mass function

    CERN Document Server

    McGee, Sean L; Balogh, Michael L

    2013-01-01

    Several recent observational studies have concluded that the initial mass function (IMF) of stars varies systematically with galaxy properties such as velocity dispersion. In this paper, we investigate the effect of linking the circular velocity of galaxies, as determined from the Fundamental Plane and Tully-Fisher relations, to the slope of the IMF with parameterizations guided by several of these studies. For each empirical relation, we generate stellar masses of ~600,000 SDSS galaxies at z ~ 0.1, by fitting the optical photometry to large suites of synthetic stellar populations that sample the full range of galaxy parameters. We generate stellar mass functions and examine the stellar-to-halo mass relations using sub-halo abundance matching. At the massive end, the stellar mass functions become a power law, instead of the familiar exponential decline. As a result, it is a generic feature of these models that the central galaxy stellar-to-halo mass relation is significantly flatter at high masses (slope ~ -0...

  13. Virial and Jet-induced Velocities in Seyfert Galaxies. III. Galaxy Luminosity as Virial Parameter

    Science.gov (United States)

    Whittle, Mark

    1992-03-01

    -Jackson relation. The offset may be viewed in two ways. Either FWHM_[O III]~ 0.7 x FWHM_stars_, or Seyfert galaxies are ~1 mag more luminous than normal spirals for a given bulge (or total) mass. The possibility that Seyfert galaxies are overluminous is investigated using the Tully-Fisher relation, M_tot_ versus {DELTA}V^c^_rot_. There is some indication that Seyfert galaxies, particularly those of early type, are offset, although the effect is confused by the underlying Hubble-type dependence of the Tully-Fisher relation. The situation is clarified using a normalized Tully-Fisher plot in which this type dependence is removed. It seems that Seyfert galaxies are indeed offset relative to normal spirals (P_null_ ~ 10^-5^), implying M/L ratios lower by a factor ~1.5-2.0. Both the Faber-Jackson and Tully-Fisher offsets for Seyfert galaxies are compared to similar offsets found previously for peculiar radio galaxies and spirals in compact groups. It is possible that enhanced star formation causes lower M/L ratios in Seyfert galaxies, although the absence of a correlation between offset and galaxy color excess fails to support this possibility. Offsets on the M_bul_ versus [O III] FWHM plot are further analyzed by introducing additional variables. There is no dependence on Seyfert type, inclination, Hubble type, or redshift. Unbarred Seyfert galaxies show a tighter correlation than barred Seyfert galaxies (P_null_ ~ 0.04) suggesting that bars can modify the NLR velocity field. The strongest result, however, is that disturbed and interacting Seyfert galaxies have significantly broader lines (P_null_ ~ 10^-4^), showing that external perturbations can influence nuclear gas. A plot of Faber-Jackson offsets against perturbation class (a 1-6 ranking scale based on Dahari's IAC parameter) shows a positive correlation which converges on zero offset for maximally disturbed galaxies. If offsets reflect dissipational settling of gas into a soft nuclear potential, then external perturbations may

  14. COSMICFLOWS-2: THE DATA

    Energy Technology Data Exchange (ETDEWEB)

    Tully, R. Brent; Courtois, Hélène M.; Jacobs, Bradley A.; Wu, Po-Feng [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, HI 96822 (United States); Dolphin, Andrew E. [Raytheon Company, 1151 E Hermans Rd., Tucson, AZ 85756 (United States); Fisher, J. Richard [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Héraudeau, Philippe [Argelander-Institut für Astronomie, Auf dem Hügel 71, D-53121 Bonn (Germany); Karachentsev, Igor D.; Makarov, Dmitry; Makarova, Lidia; Mitronova, Sofia [Special Astrophysical Observatory, N Arkhyz, KChR 369167 (Russian Federation); Rizzi, Luca [W. M. Keck Observatory, 65-1120 Mamalahoa Highway, Waimea, HI 96743 (United States); Shaya, Edward J. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Sorce, Jenny G. [Université Claude Bernard Lyon I, Institut de Physique Nucleaire, F-69622 Lyon (France)

    2013-10-01

    Cosmicflows-2 is a compilation of distances and peculiar velocities for over 8000 galaxies. Numerically the largest contributions come from the luminosity-line width correlation for spirals, the Tully-Fisher relation (TFR), and the related fundamental plane relation for E/S0 systems, but over 1000 distances are contributed by methods that provide more accurate individual distances: Cepheid, tip of the red giant branch (TRGB), surface brightness fluctuation, Type Ia supernova, and several miscellaneous but accurate procedures. Our collaboration is making important contributions to two of these inputs: TRGB and TFR. A large body of new distance material is presented. In addition, an effort is made to ensure that all the contributions, both our own and those from the literature, are on the same scale. Overall, the distances are found to be compatible with a Hubble constant H {sub 0} = 74.4 ± 3.0 km s{sup –1} Mpc{sup –1}. The great interest going forward with this data set will be with velocity field studies. Cosmicflows-2 is characterized by a great density and high accuracy of distance measures locally, falling to sparse and coarse sampling extending to z = 0.1.

  15. Numerical and Analytical Modelling of Galaxy Formation and Evolution

    CERN Document Server

    Frenk, C S; Cole, S; Lacey, C

    1996-01-01

    We review recent developments in theoretical studies of galaxy formation and evolution. In combination with new data from HST, Keck and other large telescopes, numerical and semi-analytic modelling is beginning to build up a coherent picture of galaxy formation. We summarize the current status of modelling of various galactic properties such as the structure of dark matter halos, the galaxy luminosity function, the Tully-Fisher relation, the colour-magnitude relation for ellipticals, the gross morphological properties of galaxies and the counts of faint galaxies as a function of magnitude, redshift and morphology. Many of these properties can be explained, at least at some level, within a broad class of CDM cosmologies, but a number of fundamental issues remain unresolved. We use our semi-analytic model of galaxy formation to interpret the evolutionary status of the Lyman-break galaxies at $z\\simeq 3-3.5$ recently discovered by Steidel et al. The abundance and global properties of these objects are compatible...

  16. Quantum Celestial Mechanics: Large-scale Gravitational Quantization States in Galaxies and the Universe

    Science.gov (United States)

    Preston, Howard G.; Potter, Franklin

    2006-03-01

    We report a new theory of celestial mechanics for gravitationally bound systems based upon a gravitational wave equation derived from the general relativistic Hamilton-Jacobi equation. The single ad hoc assumption is that the large-scale physical properties depend only on the ratio of the bound system's total angular momentum to its total mass. The theory predicts quantization states for the Solar System and for galaxies. The galactic quantization determines the energy and angular momentum eigenstates without requiring dark matter, and predicts expressions for the galactic disk rotation velocity, the baryonic Tully-Fisher relation, the MOND acceleration parameter, the large-angle gravitational lensing, and the shape, stability and number of arms in spiral galaxies. Applied to the universe, the theory has a repulsive effective gravitational potential that predicts a new Hubble relation and explains the observed apparent acceleration of distant supernovae with the matter/energy density of the universe at the critical density with only about 5% matter content. We suggest a laboratory experiment with a torsion bar near a rotating mass. This theory is not quantum gravity.

  17. The MOND Fundamental Plane

    CERN Document Server

    Cardone, V F; Diaferio, A; Tortora, C; Molinaro, R

    2010-01-01

    Modified Newtonian Dynamics (MOND) has been shown to be able to fit spiral galaxy rotation curves as well as giving a theoretical foundation for empirically determined scaling relations, such as the Tully - Fisher law, without the need for a dark matter halo. As a complementary analysis, one should investigate whether MOND can also reproduce the dynamics of early - type galaxies (ETGs) without dark matter. As a first step, we here show that MOND can indeed fit the observed central velocity dispersion $\\sigma_0$ of a large sample of ETGs assuming a simple MOND interpolating functions and constant anisotropy. We also show that, under some assumptions on the luminosity dependence of the Sersic n parameter and the stellar M/L ratio, MOND predicts a fundamental plane for ETGs : a log - linear relation among the effective radius $R_{eff}$, $\\sigma_0$ and the mean effective intensity $\\langle I_e \\rangle$. However, we predict a tilt between the observed and the MOND fundamental planes.

  18. 3D spectroscopic surveys: Exploring galaxy evolution mechanisms

    CERN Document Server

    Epinat, Benoît

    2011-01-01

    I review the major surveys of high redshift galaxies observed using integral field spectroscopy techniques in the visible and in the infrared. The comparison of various samples has to be done with care since they have different properties linked to their parent samples, their selection criteria and the methods used to study them. I present the various kinematic types of galaxies that are identified within these samples (rotators, mergers, etc.) and summarize the discussions on the mass assembly processes at various redshifts deduced from these classifications: at intermediate redshift (z~0.6) merger may be the main mass assembly process whereas the role of cold gas accretion along cosmic web filaments may increase with redshift. The baryonic Tully-Fisher relation is also discussed. This relation seems to be already in place 3 Gyr after the Big-Bang and is then evolving until the present day. This evolution is interpreted as an increase of the stellar mass content of dark matter haloes of a given mass. The dis...

  19. Galaxy distances and deviations from universal expansion; Proceedings of the NATO Advanced Research Workshop, Kona, HI, Jan. 13-17, 1986

    Science.gov (United States)

    Madore, Barry F. (Editor); Tully, R. Brent (Editor)

    1986-01-01

    A collection of papers on galaxy distances and deviations from universal expansion is presented. Individual topics addressed include: new results on the distance scale and the Hubble constant, Magellanic Clouds and the distance scale, CCD observations of Cepheids in nearby galaxies, distances using A supergiant stars, infrared calibration of the Cepheid distance scale, two stepping stones to the Hubble constant, physical models of supernovae and the distance scale, 21 cm line widths and distances of spiral galaxies, infrared color-luminosity relations for field galaxies, minimizing the scatter in the Tully-Fisher relation, photometry of galaxies and the local peculiar motion, elliptical galaxies and nonuniformities in the Hubble flow, and large-scale anisotropy in the Hubble flow. Also discussed are: improved distance indicator for elliptical galaxies, anisotropy of galaxies detected by IRAS, the local gravitational field, measurements of the CBR, measure of cosmological times, ages from nuclear cosmochronology, extragalactic gas at high redshift, supercluster infall models, Virgo infall and the mass density of the universe, dynamics of superclusters and Omega(0), distribution of galaxies versus dark matter, peculiar velocities and galaxy formation, cosmological shells and blast waves.

  20. NIHAO X: Reconciling the local galaxy velocity function with Cold Dark Matter via mock HI observations

    CERN Document Server

    Macciò, Andrea V; Dutton, Aaron A; Obreja, Aura; Wang, Liang; Stinson, Greg R; Kang, Xi

    2016-01-01

    We used 87 high resolution hydrodynamical cosmological simulations from the NIHAO suite to investigate the relation between the maximum circular velocity (Vmax) of a dark matter halo in a collisionless simulation and the velocity width of the HI gas in the same halo in the hydrodynamical simulation. These two quantities are normally used to compare theoretical and observational velocity functions and have led to a possible discrepancy between observations and predictions based on the Cold Dark Matter (CDM) model. We show that below 100 km/s, there is clear bias between HI based velocities and Vmax, that leads to an underestimation of the actual circular velocity of the halo. When this bias is taken into account the CDM model has no trouble in reproducing the observed velocity function and no lack of low velocity galaxies is actually present. Our simulations also reproduce the linewidth - stellar mass (Tully-Fisher) relation and HI sizes, indicating that the HI gas in our simulations is as extended as observed...

  1. In-N-Out: the gas cycle from dwarfs to spiral galaxies

    CERN Document Server

    Christensen, Charlotte R; Governato, Fabio; Pontzen, Andrew; Brooks, Alyson; Munshi, Ferah; Quinn, Thomas; Wadsley, James

    2015-01-01

    We examine the scalings of galactic outflows with halo mass across a suite of twenty high-resolution cosmological zoom galaxy simulations covering halo masses from 10^9.5 - 10^12 M_sun. These simulations self-consistently generate outflows from the available supernova energy in a manner that successfully reproduces key galaxy observables including the stellar mass-halo mass, Tully-Fisher, and mass-metallicity relations. We quantify the importance of ejective feedback to setting the stellar mass relative to the efficiency of gas accretion and star formation. Ejective feedback is increasingly important as galaxy mass decreases; we find an effective mass loading factor that scales as v_circ^(-2.2), with an amplitude and shape that is invariant with redshift. These scalings are consistent with analytic models for energy-driven wind, based solely on the halo potential. Recycling is common: about half the outflow mass across all galaxy masses is later re-accreted. The recycling timescale is typically about 1 Gyr, v...

  2. The Universality of the Fundamental Plane of E and S0 Galaxies Sample Definition and 1 Band Photometric Data

    CERN Document Server

    Scodeggio, M; Haynes, M P

    1998-01-01

    As part of a project to compare the Fundamental Plane and Tully-Fisher distance-scales, we present here I band CCD photometry for 636 early-type galaxies in 8 clusters and groups of galaxies. These are the A262, A1367, Coma (A1656), A2634, Cancer and Pegasus clusters, and the NGC 383 and NGC 507 groups. Sample selection, cluster properties, and cluster membership assignment criteria are discussed. We present photometric parameters that are used in the Fundamental Plane relation, the effective radius r_e and the effective surface brightness mu_e, as derived from a r^{1/4} fit to the observed radial photometric profile of each galaxy. A comparison with similar data found in the literature for the Coma cluster shows that large systematic uncertainties can be introduced in the measurement of r_e and mu_e by the particular method used to derive those parameters. However the particular combination of these two parameters that enters in the Fundamental Plane relation is a quantity that can be measured with high accu...

  3. Constraining String Gauge Field by Galaxy Rotation Curve and Planet Perihelion Precession

    CERN Document Server

    Cheung, Yeuk-Kwan Edna

    2011-01-01

    We discuss a cosmological model in which the string gauge field coupled universally to matter gives rise to an extra centripetal force and will have effects on cosmological and astronomical observations. Several tests are performed using data including galaxy rotation curves of twenty-two spiral galaxies of varied luminosities and sizes, and perihelion precessions of planets in the solar system. Remarkable fit of galaxy rotation curves is achieved using the one-parameter string model as contrasted to the three-parameter model of dark matter model with the Navarro-Frenk-White profile. The rotation curves of the same group of galaxies are independently fit using dark matter model with the generalized Navarro-Frenk-White profile and using the string model. The average chi-squared of the NFW fit is 9% better than that of the string model at a price of two more free parameters. From the string model we give a dynamical explanation of Tully-Fisher relation. We are able to derive a relation between field strength, g...

  4. Signatures of dark matter halo expansion in galaxy populations

    Science.gov (United States)

    Brook, Chris B.; Di Cintio, Arianna

    2015-10-01

    Dark matter cores within galaxy haloes can be formed by energy feedback from star-forming regions: an energy balance suggests that the maximum core formation efficiency arises in galaxies with Mstar ˜ 108.5 M⊙. We show that a model population of galaxies, in which the density profile has been modified by such baryonic feedback, is able to explain the observed galaxy velocity function and Tully-Fisher relations significantly better than a model in which a universal cuspy density profile is assumed. Alternative models, namely warm or self-interacting dark matter, also provide a better match to these observed relations than a universal profile model does, but make different predictions for how halo density profiles vary with mass compared to the baryonic feedback case. We propose that different core formation mechanisms may be distinguished based on the imprint they leave on galaxy populations over a wide range of mass. Within the current observational data we find evidence of the expected signatures of the mass dependence of core formation generated by baryonic feedback.

  5. Signatures of Dark Matter Halo Expansion in Galaxy Populations

    CERN Document Server

    Brook, Chris B

    2015-01-01

    Dark matter cores within galaxy haloes can be formed by energy feedback from star forming regions: an energy balance suggests that the maximum core formation efficiency arises in galaxies with M$_{\\star}\\sim10^{8.5}$M$_{\\odot}$. We show that a model population of galaxies, in which the density profile has been modified by such baryonic feedback, is able to explain the observed galaxy velocity function and Tully-Fisher relations significantly better than a model in which a universal cuspy density profile is assumed. Alternative models, namely warm or self-interacting dark matter, also provide a better match to these observed relations than a universal profile model does, but make different predictions for how halo density profiles vary with mass compared to the baryonic feedback case. We propose that different core formation mechanisms may be distinguished based on the imprint they leave on galaxy populations over a wide range of mass. Within the current observational data we find evidence of the expected sign...

  6. The Carnegie Hubble Program

    Science.gov (United States)

    Freedman, Wendy L.; Madore, Barry F.; Scowcroft, Vicky; Mnso, Andy; Persson, S. E.; Rigby, Jane; Sturch, Laura; Stetson, Peter

    2011-01-01

    We present an overview of and preliminary results from an ongoing comprehensive program that has a goal of determining the Hubble constant to a systematic accuracy of 2%. As part of this program, we are currently obtaining 3.6 micron data using the Infrared Array Camera (IRAC) on Spitzer, and the program is designed to include JWST in the future. We demonstrate that the mid-infrared period-luminosity relation for Cepheids at 3.6 microns is the most accurate means of measuring Cepheid distances to date. At 3.6 microns, it is possible to minimize the known remaining systematic uncertainties in the Cepheid extragalactic distance scale. We discuss the advantages of 3.6 micron observations in minimizing systematic effects in the Cepheid calibration of the Hubble constant including the absolute zero point, extinction corrections, and the effects of metallicity on the colors and magnitudes of Cepheids. We are undertaking three independent tests of the sensitivity of the mid-IR Cepheid Leavitt Law to metallicity, which when combined will allow a robust constraint on the effect. Finally, we are providing a new mid-IR Tully-Fisher relation for spiral galaxies.

  7. The SAMI galaxy survey: Galaxy Interactions and Kinematic Anomalies in Abell 119

    CERN Document Server

    Oh, Sree; Cortese, Luca; van de Sande, Jesse; Mahajan, Smriti; Jeong, Hyunjin; Sheen, Yun-Kyeong; Allen, James T; Bekki, Kenji; Bland-Hawthorn, Joss; Bloom, Jessica V; Brough, Sarah; Bryant, Julia J; Colless, Matthew; Croom, Scott M; Fogarty, L M R; Goodwin, Michael; Green, Andy; Konstantopoulos, Iraklis S; Lawrence, Jon; López-Sánchez, Á R; Lorente, Nuria P F; Medling, Anne M; Owers, Matt S; Richards, Samuel; Scott, Nicholas; Sharp, Rob; Sweet, Sarah M

    2016-01-01

    Galaxy mergers are important events that can determine the fate of a galaxy by changing its morphology, star-formation activity and mass growth. Merger systems have commonly been identified from their disturbed morphologies, and we now can employ Integral Field Spectroscopy to detect and analyze the impact of mergers on stellar kinematics as well. We visually classified galaxy morphology using deep images ($\\mu_{\\rm r} = 28\\,\\rm mag\\,\\, arcsec^{-2}$) taken by the Blanco 4-m telescope at the Cerro Tololo Inter-American Observatory. In this paper we investigate 63 bright ($M_{\\rm r}<-19.3$) spectroscopically-selected galaxies in Abell 119; of which 53 are early type and 20 galaxies show a disturbed morphology by visual inspection. A misalignment between the major axes in the photometric image and the kinematic map is conspicuous in morphologically-disturbed galaxies. Our sample is dominated by early-type galaxies, yet it shows a surprisingly tight Tully-Fisher relation except for the morphologically-disturbe...

  8. Bayesian 3D velocity field reconstruction with VIRBIUS

    Science.gov (United States)

    Lavaux, Guilhem

    2016-03-01

    I describe a new Bayesian-based algorithm to infer the full three dimensional velocity field from observed distances and spectroscopic galaxy catalogues. In addition to the velocity field itself, the algorithm reconstructs true distances, some cosmological parameters and specific non-linearities in the velocity field. The algorithm takes care of selection effects, miscalibration issues and can be easily extended to handle direct fitting of e.g. the inverse Tully-Fisher relation. I first describe the algorithm in details alongside its performances. This algorithm is implemented in the VIRBIUS (VelocIty Reconstruction using Bayesian Inference Software) software package. I then test it on different mock distance catalogues with a varying complexity of observational issues. The model proved to give robust measurement of velocities for mock catalogues of 3000 galaxies. I expect the core of the algorithm to scale to tens of thousands galaxies. It holds the promises of giving a better handle on future large and deep distance surveys for which individual errors on distance would impede velocity field inference.

  9. The Impact of Baryonic Physics on the Structure of Dark Matter Halos: the View from the FIRE Cosmological Simulations

    Science.gov (United States)

    Keung Chan, Tsang; Keres, Dusan; Oñorbe, Jose; Hopkins, Philip F.; Muratov, Alexander; Faucher-Giguere, Claude-Andre; Quataert, Eliot

    2016-06-01

    We study the distribution of cold dark matter (CDM) in cosmological simulations from the FIRE (Feedback In Realistic Environments) project, which incorporates explicit stellar feedback in the multi-phase ISM, with energetics from stellar population models. We find that stellar feedback, without ``fine-tuned'' parameters, greatly alleviates small-scale problems in CDM. Feedback causes bursts of star formation and outflows, altering the DM distribution. As a result, the inner slope of the DM halo profile (α) shows a strong mass dependence: profiles are shallow at Mh ∼ 1010-1011 M⊙ and steepen at higher/lower masses. The resulting core sizes and slopes are consistent with observations. Because the star formation efficiency, Ms/Mh is strongly halo mass dependent, a rapid change in α occurs around Mh ∼1010M⊙, (Ms∼106-107M⊙) as sufficient feedback energy becomes available to perturb the DM. Large cores are not established during the period of rapid growth of halos because of ongoing DM mass accumulation. Instead, cores require several bursts of star formation after the rapid buildup has completed. Stellar feedback dramatically reduces circular velocities in the inner kpc of massive dwarfs; this could be sufficient to explain the ``Too Big To Fail'' problem without invoking non-standard DM. Finally, feedback and baryonic contraction in Milky Way-mass halos produce DM profiles slightly shallower than the Navarro-Frenk-White profile, consistent with the normalization of the observed Tully-Fisher relation.

  10. How the First Stars Shaped the Faintest Gas-dominated Dwarf Galaxies

    Science.gov (United States)

    Verbeke, R.; Vandenbroucke, B.; De Rijcke, S.

    2015-12-01

    Low-mass dwarf galaxies are very sensitive test-beds for theories of cosmic structure formation since their weak gravitational fields allow the effects of the relevant physical processes to clearly stand out. Up to now, no unified account has existed of the sometimes seemingly conflicting properties of the faintest isolated dwarfs in and around the Local Group, such as Leo T and the recently discovered Leo P and Pisces A systems. Using new numerical simulations, we show that this serious challenge to our understanding of galaxy formation can be effectively resolved by taking into account the regulating influence of the ultraviolet radiation of the first population of stars on a dwarf's star formation rate while otherwise staying within the standard cosmological paradigm for structure formation. These simulations produce faint, gas-dominated, star-forming dwarf galaxies that lie on the baryonic Tully-Fisher relation and that successfully reproduce a broad range of chemical, kinematical, and structural observables of real late-type dwarf galaxies. Furthermore, we stress the importance of obtaining properties of simulated galaxies in a manner as close as possible to the typically employed observational techniques.

  11. Ionized gas disks in Elliptical and S0 galaxies at $z<1$

    CERN Document Server

    Jaffe, Yara L; Ziegler, Bodo; Kuntschner, Harald; Zaritsky, Dennis; Rudnick, Gregory; Poggianti, Bianca M; Hoyos, Carlos; Halliday, Claire; Demarco, Ricardo

    2014-01-01

    We analyse the extended, ionized-gas emission of 24 early-type galaxies (ETGs) at $0Tully-Fisher relation of the ETGs with gas disks, and compare them to EDisCS spirals. Taking a matched range of redshifts, $M_{B}<-20$, and excluding galaxies with large velocity uncertainties, we find that, at fixed rotational velocity, ETGs ar...

  12. Boxy Hα emission profiles in star-forming galaxies

    Science.gov (United States)

    Chen, Yan-Mei; Gu, Qiu-Sheng; Tremonti, Christy A.; Shi, Yong; Jin, Yifei

    2016-07-01

    We assemble a sample of disc star-forming galaxies from the Sloan Digital Sky Survey Data Release 7, studying the structure of Hα emission lines, finding a large fraction of this sample contains boxy Hα line profiles. This fraction depends on galaxy physical and geometric parameters in the following way: (1) it increases monotonically with star formation rate per unit area (ΣSFR), and stellar mass (M*), with the trend being much stronger with M*, from ˜0 per cent at M* = 1010 M⊙ to about 50 per cent at M* = 1011 M⊙; (2) the fraction is much smaller in face-on systems than in edge-on systems. It increases with galaxy inclination (i) while i < 60° and is roughly a constant of 25 per cent beyond this range; (3) for the sources which can be modelled well with two velocity components, blueshifted and redshifted from the systemic velocity, these is a positive correlation between the velocity difference of these two components and the stellar mass, with a slope similar to the Tully-Fisher relation; (4) the two components are very symmetric in the mean, both in velocity and in amplitude. The four findings listed above can be understood as a natural result of a rotating galaxy disc with a kpc-scale ring-like Hα emission region.

  13. The effect of the environment on the gas kinematics and the structure of distant galaxies

    CERN Document Server

    Jaffé, Yara L; Kuntschner, Harald; Bamford, Steven; Hoyos, Carlos; De Lucia, Gabriella; Halliday, Claire; Milvang-Jensen, \\and Bo; Poggianti, Bianca; Rudnick, Gregory; Saglia, Roberto P; Sanchez-Blazquez, Patricia; Zaritsky, Dennis

    2011-01-01

    With the aim of distinguishing between possible physical mechanisms acting on galaxies when they fall into clusters, we study the properties of the gas and the stars in a sample of 422 emission-line galaxies from EDisCS in different environments up to z~1. We identify galaxies with kinematical disturbances (from emission-lines in their 2D spectra) and find that they are more frequent in clusters than in the field. The fraction of kinematically-disturbed galaxies increases with cluster velocity dispersion and decreases with distance from the cluster centre, but remains constant with projected galaxy density. We also studied morphological disturbances in the stellar light from HST/F814W images, finding that the fraction of morphologically disturbed galaxies is similar in all environments. Moreover, there is little correlation between the presence of kinematically-disturbed gas and morphological distortions. We also study the dependence of the Tully-Fisher relation, star formation, and extent of the emission on ...

  14. The 6dF Galaxy Velocity Survey: Cosmological constraints from the velocity power spectrum

    CERN Document Server

    Johnson, Andrew; Koda, Jun; Ma, Yin-Zhe; Colless, Matthew; Crocce, Martin; Davis, Tamara M; Jones, Heath; Lucey, John R; Magoulas, Christina; Mould, Jeremy; Scrimgeour, Morag; Springob, Christopher M

    2014-01-01

    We present the first scale-dependent measurements of the normalised growth rate of structure $f\\sigma_{8}(k, z=0)$ using only the peculiar motions of galaxies. We use data from the 6-degree Field Galaxy Survey velocity sample (6dFGSv) together with a newly-compiled sample of low-redshift $(z 300 h^{-1}{\\rm Mpc}$, which represents the largest-scale growth rate measurement to date. We find no evidence for a scale dependence in the growth rate, or any statistically significant variation from the growth rate as predicted by the Planck cosmology. Bringing all the scales together, we determine the normalised growth rate at $z=0$ to $\\sim15%$ in a manner independent of galaxy bias and in excellent agreement with the constraint from the measurements of redshift-space distortions from 6dFGS. We pay particular attention to systematic errors. We point out that the intrinsic scatter present in Fundamental-Plane and Tully-Fisher relations is only Gaussian in logarithmic distance units; wrongly assuming it is Gaussian in l...

  15. ALFALFA Discovery of the Nearby Gas-rich Dwarf Galaxy Leo P. V. Neutral Gas Dynamics and Kinematics

    CERN Document Server

    Bernstein-Cooper, Elijah Z; Elson, Edward C; Warren, Steven R; Chengalur, Jayaram; Skillman, Evan D; Adams, Elizabeth A K; Bolatto, Alberto D; Giovanelli, Riccardo; Haynes, Martha P; McQuinn, Kristen B W; Pardy, Stephen A; Rhode, Katherine L; Salzer, John J

    2014-01-01

    We present new HI spectral line imaging of the extremely metal-poor, star-forming dwarf irregular galaxy Leo P. Our HI images probe the global neutral gas properties and the local conditions of the interstellar medium (ISM). The HI morphology is slightly elongated along the optical major-axis. We do not find obvious signatures of interaction or infalling gas at large spatial scales. The neutral gas disk shows obvious rotation, although the velocity dispersion is comparable to the rotation velocity. The rotation amplitude is estimated to be V_c = 15 +/- 5 km/s. Within the HI radius probed by these observations, the mass ratio of gas to stars is roughly 2:1, while the ratio of the total mass to the baryonic mass is ~15:1. We use this information to place Leo P on the baryonic Tully-Fisher relation, testing the baryonic content of cosmic structures in a sparsely populated portion of parameter space that has hitherto been occupied primarily by dwarf spheroidal galaxies. We detect the signature of two temperature ...

  16. ALFALFA Discovery of the Nearby Gas-Rich Dwarf Galaxy Leo P. I. HI Observations

    CERN Document Server

    Giovanelli, Riccardo; Adams, Elizabeth A K; Cannon, John M; Rhode, Katherine L; Salzer, John J; Skillman, Evan D; Bernstein-Cooper, Elijah Z; McQuinn, Kristen B W

    2013-01-01

    The discovery of a previously unknown 21cm HI line source identified as an ultra-compact high velocity cloud in the ALFALFA survey is reported. The HI detection is barely resolved by the Arecibo 305m telescope ~4' beam and has a narrow HI linewidth (HPFW of 24 km/s). Further HI observations at Arecibo and with the VLA corroborate the ALFALFA HI detection, provide an estimate of the HI radius, ~1' at the 5 x 10^19 cm^-2 isophote, and show the cloud to exhibit rotation with an amplitude of ~9.0 +/- 1.5 km/s. In other papers, Rhode et al. (2013) show the HI source to have a resolved stellar counterpart and ongoing star forming activity, while Skillman et al. (2013) reveal it as having extremely low metallicity: 12 + log(O/H) = 7.16 +/- 0.04. The HI mass to stellar mass ratio of the object is found to be 2.6. We use the Tully-Fisher template relation in its baryonic form (McGaugh 2012) to obtain a distance estimate D = 1.3 (+0.9,-0.5) Mpc. Additional constraints on the distance are also provided by the optical da...

  17. SHIELD: Neutral Gas Kinematics and Dynamics

    Science.gov (United States)

    McNichols, Andrew; Teich, Yaron; Cannon, John M.; SHIELD Team

    2016-01-01

    The "Survey of HI in Extremely Low-mass Dwarfs" (SHIELD) is a multiwavelength, legacy-class observational study of 12 low-mass dwarf galaxies discovered in Arecibo Legacy Fast ALFA (ALFALFA) survey data products. Here we present new results of detailed kinematic analyses of these systems using multi-configuration, high spatial (˜300 pc) and spectral (0.82 - 2.46 km s-1 ch-1) resolution HI observations from the Karl G. Jansky Very Large Array. For each source, we produce velocity fields and dispersion maps using different spatial and spectral resolution representations of the data in order to attempt derivation of an inclination-corrected rotation curve. While both two- and three-dimensional fitting techniques are employed, the comparable magnitudes of velocity dispersion and projected rotation result in degeneracies that prohibit unambiguous circular velocity solutions. We thus make multiple position-velocity cuts across each galaxy to determine the maximum circular rotation velocity (≤ 30 km-1 for the survey population). Baryonic masses are calculated using single-dish H I fluxes from Arecibo and stellar masses derived from HST and Spitzer imaging. Comparison is made with total dynamical masses estimated from the position-velocity analysis. The SHIELD galaxies are contextualized on the baryonic Tully-Fisher relation.Support for this work was provided by NSF grant AST-1211683 to JMC at Macalester College.

  18. Constraining the subgrid physics in simulations of isolated dwarf galaxies

    CERN Document Server

    Vandenbroucke, Bert; De Rijcke, Sven

    2016-01-01

    Simulating dwarf galaxy halos in a reionizing Universe puts severe constraints on the sub-grid model employed in the simulations. Using the same sub-grid model that works for simulations without a UV-background (UVB) results in gas poor galaxies that stop forming stars very early on, except for halos with high masses. This is in strong disagreement with observed galaxies, which are gas rich and star forming down to a much lower mass range. To resolve this discrepancy, we ran a large suite of isolated dwarf galaxy simulations to explore a wide variety of sub-grid models and parameters, including timing and strength of the UVB, strength of the stellar feedback, and metallicity dependent Pop III feedback. We compared these simulations to observed dwarf galaxies by means of the baryonic Tully-Fisher relation (BTFR), which links the baryonic content of a galaxy to the observationally determined strength of its gravitational potential. We found that the results are robust to changes in the UVB. The strength of the ...

  19. Constraining the subgrid physics in simulations of isolated dwarf galaxies

    Science.gov (United States)

    Vandenbroucke, Bert; Verbeke, Robbert; De Rijcke, Sven

    2016-05-01

    Simulating dwarf galaxy haloes in a reionizing Universe puts severe constraints on the subgrid model employed in the simulations. Using the same subgrid model that works for simulations without a UV-background (UVB) results in gas-poor galaxies that stop forming stars very early on, except for haloes with high masses. This is in strong disagreement with observed galaxies, which are gas rich and star forming down to a much lower mass range. To resolve this discrepancy, we ran a large suite of isolated dwarf galaxy simulations to explore a wide variety of subgrid models and parameters, including timing and strength of the UVB, strength of the stellar feedback and metallicity-dependent Pop III feedback. We compared these simulations to observed dwarf galaxies by means of the baryonic Tully-Fisher relation (BTFR), which links the baryonic content of a galaxy to the observationally determined strength of its gravitational potential. We found that the results are robust to changes in the UVB. The strength of the stellar feedback shifts the results on the BTFR, but does not help to form gas-rich galaxies at late redshifts. Only by including Pop III feedback are we able to produce galaxies that lie on the observational BTFR and that have neutral gas and ongoing star formation at redshift zero.

  20. HST + Keck Study of Disk Systems in Galaxy Cluster Cl0024+16 at Redshift z = 0.39

    Science.gov (United States)

    Koo, David

    2001-07-01

    For over twenty years, distant galaxy clusters have been a key arena for galaxy evolution studies. Despite enormous strides, our understanding of the physical mechanisms that drive distant cluster evolution remain largely theoretical and untested. Infall of groups, merging, ``harassment'', quenching of star formation, starbursts, and ram-pressure stripping all remain viable ideas. Virtually all of these mechanisms involve disks and gas. Therefore, in contrast to recent studies that focus on spheroids, we believe a more promising approach to track these physical processes would be detailed studies of cluster disk systems. This archive proposal asks support to launch a two-pronged attack to analyze an ideal, rich data set -- and one that is already in hand. One prong exploits deep B and I HST imaging of Cl 0024+1654 at z 0.39. The other prong complements the HST data with very high quality Keck spectra of over 80 sources within the HST WFPC2 field. With both data sets, we will answer two questions that highlight the physical processes which affect cluster disk evolution: {1} How do the structures, ages, and age distribution of S0 disks compare to S0 bulges at z 0.4? {2} How does the Tully-Fisher relation and M/L of cluster disk systems differ from those in the field, and what properties of the cluster galaxies correlate with these deviations?

  1. Cosmological Parameters from the Comparison of the 2MASS Gravity Field with Peculiar Velocity Surveys

    CERN Document Server

    Pike, R W; Hudson, Michael J.

    2005-01-01

    We compare the peculiar velocity field within 65 $h^{-1}$ Mpc predicted from 2MASS photometry and public redshift data to three independent peculiar velocity surveys based on type Ia supernovae, surface brightness fluctuations in ellipticals, and Tully-Fisher distances to spirals. The three peculiar velocity samples are each in good agreement with the predicted velocities and produce consistent results for $\\beta_{K}=\\Omega\\sbr{m}^{0.6}/b_{K}$. Taken together the best fit $\\beta_{K} = 0.49 \\pm 0.04$. We explore the effects of morphology on the determination of $\\beta$ by splitting the 2MASS sample into E+S0 and S+Irr density fields and find both samples are equally good tracers of the underlying dark matter distribution, but that early-types are more clustered by a relative factor $b\\sbr{E}/b\\sbr{S} \\sim 1.6$. The density fluctuations of 2MASS galaxies in $8 h^{-1}$ Mpc spheres in the local volume is found to be $\\sigma\\sbr{8,K} = 0.9$. From this result and our value of $\\beta_{K}$, we find $\\sigma_8 (\\Omega\\...

  2. Galaxies with conspicuous optical warps

    CERN Document Server

    Reshetnikov, Vladimir P; Moiseev, Alexei V; Kotov, Sergey S; Savchenko, Sergey S

    2016-01-01

    In this paper, we present results of a photometric and kinematic study for a sample of 13 edge-on spiral galaxies with pronounced integral-shape warps of their stellar discs. The global structure of the galaxies is analyzed on the basis of the Sloan Digital Sky Survey (SDSS) imaging, in the g, r and i passbands. Spectroscopic observations are obtained with the 6-m Special Astrophysical Observatory telescope. In general, galaxies of the sample are typical bright spiral galaxies satisfying the Tully-Fisher relation. Most of the galaxies reside in dense spatial environments and, therefore, tidal encounters are the most probable mechanism for generating their stellar warps. We carried out a detailed analysis of the galaxies and their warps and obtained the following main results: (i) maximum angles of stellar warps in our sample are about 20{\\deg}; (ii) warps start, on average, between 2 and 3 exponential scale lengths of a disc; (iii) stronger warps start closer to the center, weak warps start farther; (iv) warp...

  3. A Dark Hydrogen Cloud in the Virgo Cluster

    CERN Document Server

    Minchin, R; Disney, M; Boyce, P; García, D; Jordan, C; Kilborn, V; Lang, R; Roberts, S; Sabatini, S; Van Driel, W; Minchin, Robert; Davies, Jonathan; Disney, Michael; Boyce, Peter; Garcia, Diego; Jordan, Christine; Kilborn, Virginia; Lang, Robert; Roberts, Sarah; Sabatini, Sabina; Driel, Wim van

    2005-01-01

    VIRGOHI21 is an HI source detected in the Virgo Cluster survey of Davies et al. (2004) which has a neutral hydrogen mass of 10^8 M_solar and a velocity width of Delta V_20 = 220 km/s. From the Tully-Fisher relation, a galaxy with this velocity width would be expected to be 12th magnitude or brighter; however deep CCD imaging has failed to turn up a counterpart down to a surface-brightness level of 27.5 B mag/sq. arcsec. The HI observations show that it is extended over at least 16 kpc which, if the system is bound, gives it a minimum dynamical mass of ~10^11 M_solar and a mass to light ratio of M_dyn/L_B > 500 M_solar/L_solar. If it is tidal debris then the putative parents have vanished; the remaining viable explanation is that VIRGOHI21 is a dark halo that does not contain the expected bright galaxy. This object was found because of the low column density limit of our survey, a limit much lower than that achieved by all-sky surveys such as HIPASS. Further such sensitive surveys might turn up a significant n...

  4. The fate of LSB galaxies in clusters and the origin of the diffuse intra-cluster light

    CERN Document Server

    Moore, B; Stadel, J; Quinn, T; Moore, Ben; Lake, George; Stadel, Joachim; Quinn, Thomas

    1999-01-01

    We follow the evolution of disk galaxies within a cluster that forms hierarchically in a standard cold dark matter N-body simulation. At a redshift z=0.5 we select several dark matter halos that have quiet merger histories and are about to enter the newly forming cluster environment. The halos are replaced with equilibrium high resolution model spirals that are constructed to represent luminous examples of low surface brightness (LSB) and high surface brightness (HSB) galaxies. Whilst the models have the same total luminosity, scale lengths, however they all lie at the same place on the Tully-Fisher relation. Due to their ``soft'' central potentials, LSB galaxies evolve dramatically under the influence of rapid encounters with dark matter halos, substructure and strong tidal shocks from the global cluster potential - galaxy harassment. As much as 90% of the LSB disk stars are tidally stripped and congregate in large diffuse tails that trace the orbital path of the galaxy and form the diffuse intra-cluster lig...

  5. The Formation of a Realistic Disk Galaxy in Lambda Dominated Cosmologies

    CERN Document Server

    Governato, F; Wadsley, J; Gardner, J P; Willman, B; Hayashi, E; Quinn, T; Stadel, J; Lake, G

    2002-01-01

    We present the first simulation of the formation of a realistic disk dominated galaxy in a hierarchical scenario and study its internal properties to the present epoch. We use a set of extremely high resolution SPH simulations that include cooling, star formation, SN (I&II) feedback and a UV background. We compare results from a LambdaCDM simulation with a LambdaWDM (2keV) simulation that forms significantly less small scale structure. Higher resolution and a correct treatment of cooling play a major role in solving the angular momentum catastrophe claimed from previous simulations of galaxy formation. Hence, a large disk forms without the need of strong energy injection, the z = 0 galaxies lie on the I--band Tully--Fisher relation, and the stellar material in the disk component conserves 40% and 90% of the original angular momentum in the CDM and WDM models respectively. The disk is dynamically cold when formed but gets heated by subsequent bar instabilities. The LambdaCDM galaxy has an overabundance of ...

  6. ESO 603-G21 A strange polar-ring galaxy

    CERN Document Server

    Reshetnikov, V P; De Oliveira-Abans, M

    2002-01-01

    We present the results of B, V, R surface photometry of ESO603-G21 - a galaxy with a possible polar ring. The morphological and photometric features of this galaxy are discussed. The central round object of the galaxy is rather red and presents a nearly exponential surface brightness distribution. This central structure is surrounded by a blue warped ring or disk. The totality of the observed characteristics (optical and NIR colors, strong color gradients, HI and H_2 content, FIR luminosity and star-formation rate, rotation-curve shape, global mass-to-luminosity ratio, the agreement with the Tully-Fisher relation, etc.) shows that ESO603-G21 is similar to late-type spiral galaxies. We suppose that morphological peculiarities and the possible existence of two large-scale kinematically-decoupled subsystems in ESO603-G21 can be explained as being a result of dissipative merging of two spiral galaxies or as a consequence of a companion accretion onto a pre-existing spiral host.

  7. ESO 603-G21: A strange polar-ring galaxy

    Science.gov (United States)

    Reshetnikov, V. P.; Faúndez-Abans, M.; de Oliveira-Abans, M.

    2002-02-01

    We present the results of B, V, R surface photometry of ESO 603-G21 - a galaxy with a possible polar ring. The morphological and photometric features of this galaxy are discussed. The central round object of the galaxy is rather red and presents a nearly exponential surface brightness distribution. This central structure is surrounded by a blue warped ring or disk. The totality of the observed characteristics (optical and NIR colors, strong color gradients, HI and H_2 content, FIR luminosity and star-formation rate, rotation-curve shape, global mass-to-luminosity ratio, the agreement with the Tully-Fisher relation, etc.) shows that ESO 603-G21 is similar to late-type spiral galaxies. We suppose that morphological peculiarities and the possible existence of two large-scale kinematically-decoupled subsystems in ESO 603-G21 can be explained as being a result of dissipative merging of two spiral galaxies or as a consequence of a companion accretion onto a pre-existing spiral host. Based on observations made at the Observatório do Pico dos Dias (OPD), operated by the MCT/Laboratório Nacional de Astrofísica, Brazil.

  8. Hyper-Fit: Fitting Linear Models to Multidimensional Data with Multivariate Gaussian Uncertainties

    CERN Document Server

    Robotham, A S G

    2015-01-01

    Astronomical data is often uncertain with errors that are heteroscedastic (different for each data point) and covariant between different dimensions. Assuming that a set of D-dimensional data points can be described by a (D - 1)-dimensional plane with intrinsic scatter, we derive the general likelihood function to be maximised to recover the best fitting model. Alongside the mathematical description, we also release the hyper-fit package for the R statistical language (github.com/asgr/hyper.fit) and a user-friendly web interface for online fitting (hyperfit.icrar.org). The hyper-fit package offers access to a large number of fitting routines, includes visualisation tools, and is fully documented in an extensive user manual. Most of the hyper-fit functionality is accessible via the web interface. In this paper we include applications to toy examples and to real astronomical data from the literature: the mass-size, Tully-Fisher, Fundamental Plane, and mass-spin-morphology relations. In most cases the hyper-fit ...

  9. The interstellar medium in galaxies

    CERN Document Server

    1997-01-01

    It has been more than five decades ago that Henk van de Hulst predicted the observability of the 21-cm line of neutral hydrogen (HI ). Since then use of the 21-cm line has greatly improved our knowledge in many fields and has been used for galactic structure studies, studies of the interstellar medium (ISM) in the Milky Way and other galaxies, studies of the mass distribution of the Milky Way and other galaxies, studies of spiral struc­ ture, studies of high velocity gas in the Milky Way and other galaxies, for measuring distances using the Tully-Fisher relation etc. Regarding studies of the ISM, there have been a number of instrumen­ tal developments over the past decade: large CCD's became available on optical telescopes, radio synthesis offered sensitive imaging capabilities, not only in the classical 21-cm HI line but also in the mm-transitions of CO and other molecules, and X-ray imaging capabilities became available to measure the hot component of the ISM. These developments meant that Milky Way was n...

  10. New multi-zoom method for N-body simulations: application to galaxy growth by accretion

    CERN Document Server

    Semelin, B

    2005-01-01

    In this work we focus on the properties of accretion onto galaxies. Through numerical simulations we investigate the geometrical properties of accretion. To span the scale range required in these simulations we have developed a new numerical technique: the multi-zoom method. We run a series of Tree-SPH simulations in smaller and smaller boxes at higher and higher mass resolution, using data recorded at the previous level to account for the matter inflow and the tidal field from outside matter. The code is parallelized using OpenMP. We present a validation test to evaluate the robustness of the method: the pancake collapse. We apply this new multizoom method to study the accretion properties. Zooming in onto galaxies from a cosmological simulation, we select a sample of 10 well resolved galaxies (5000 baryonic particles or more). We sum up their basic properties and plot a Tully-Fisher relation. We find that smooth accretion of intergalactic cold gas dominates mergers for the mass growth of galaxies at z < ...

  11. Dynamical and Stellar Masses of Lyman-alpha Galaxies

    Science.gov (United States)

    Rhoads, James E.; Malhotra, S.; McLinden, E.; Richardson, M. L.; Finkelstein, S. L.; Tilvi, V. S.

    2012-01-01

    We have observed strong nebular lines of [OIII] and H alpha for Lyman-alpha galaxies at z=2-3.1 using Keck+NIRSPEC, LBT+LUCIFER, and Gemini+NIFS. [OIII] 5007 is strong enough to dominate the 2 micron K band fluxes of these galaxies, and leads to an overestimate of the stellar mass of the galaxy by an order of magnitude. After correcting for the observed [OIII] lines, we infer low masses and young ages for these galaxies. We also use the physical widths of the rest-optical lines, combined with spatial sizes from HST imaging, to obtain direct dynamical mass estimates of Lyman alpha galaxies (which cannot be done using the resonantly scattered Lyman alpha line). Finally, we combine our stellar mass estimates and line widths to place these galaxies on the baryonic Tully-Fisher relation. We find that the stellar masses required to reproduce the observed light are lower than one would expect based on the galaxies' line widths. The stellar mass densities of these galaxies are comparable to those of elliptical galaxies today. We gratefully acknowledge support from NSF grant NSF-AST-0808165.

  12. Deep NIR photometry of HI galaxies in the Zone of Avoidance

    CERN Document Server

    Williams, Wendy L; Woudt, Patrick A

    2014-01-01

    Current studies of the peculiar velocity flow field in the Local Universe are limited by either the lack of detection or accurate photometry for galaxies at low Galactic latitudes. The contribution to the dynamics of the Local Group of the largely unknown mass distribution in this 'Zone of Avoidance' remains controversial. We present here the results of a pilot project to obtain deep near infrared (NIR) observations of galaxies detected in the systematic Parkes deep HI survey of the ZoA - 578 galaxies with recession velocities out to 6000 km/s were observed with the 1.4m InfraRed Survey Facility SIRIUS camera providing J, H and K_s imaging ~2 mag deeper than 2MASS. After star-subtraction, the resulting isophotal magnitudes and inclinations of ZoA galaxies are of sufficient accuracy (magnitude errors under 0.1 mag even at high extinction) to ultimately be used to determine cosmic flow fields "in" the ZoA via the NIR Tully-Fisher relation. We further used the observed NIR colours to assess the ratio of the true...

  13. Halo and Subhalo Demographics with Planck Cosmological Parameters: Bolshoi-Planck and MultiDark-Planck Simulations

    CERN Document Server

    Rodriguez-Puebla, Aldo; Primack, Joel; Klypin, Anatoly; Lee, Christoph; Hellinger, Doug

    2016-01-01

    We report and provide fitting functions for the abundance of dark matter halos and subhalos as a function of mass, circular velocity, and redshift from the new Bolshoi-Planck and MultiDark-Planck $\\Lambda$CDM cosmological simulations, based on the Planck cosmological parameters. We also report the halo mass accretion rates, which may be connected with galaxy star formation rates. We show that the higher cosmological matter density of the Planck parameters compared with the WMAP parameters leads to higher abundance of massive halos at high redshifts. We find that the median halo spin parameter $\\lambda_{\\rm B} = J(2M_{\\rm vir}R_{\\rm vir}V_{\\rm vir})^{-1}$ is nearly independent of redshift, leading to predicted evolution of galaxy sizes that is consistent with observations, while the significant decrease with redshift in median $\\lambda_{\\rm P} = J|E|^{-1/2}G^{-1}M^{-5/2}$ predicts more decrease in galaxy sizes than is observed. Using the Tully-Fisher and Faber-Jackson relations between galaxy velocity and mass...

  14. HR-Cosmos: Kinematics of Star-Forming Galaxies at z $\\sim$ 0.9

    CERN Document Server

    Pelliccia, D; Epinat, B; Ilbert, O; Scoville, N; Amram, P; Lemaux, B C; Zamorani, G

    2016-01-01

    We present the kinematic analysis of a sub-sample of 82 galaxies at $\\mathrm{0.75Tully-Fisher relation at $z\\simeq 0.9$ with high-quality stellar mass measurements derived using the latest COSMOS photometric catalog, which includes the latest data releases of UltraVISTA and \\emph{Spitzer}. In doubling the sample ...

  15. The magnification of SN 1997ff, the farthest known supernova

    Energy Technology Data Exchange (ETDEWEB)

    Benitez, Narciso; Riess, Adam; Nugent, Peter; Dickinson, Mark; Chornock, Ryan; Filippenko, Alexei V.

    2002-09-03

    With a redshift of z {approx} 1.7, SN 1997ff is the most distant type Ia supernova discovered so far. This SN is close to several bright, z = 0.6-0.9 galaxies, and we consider the effects of lensing by those objects on the magnitude of SN 1997ff. We estimate their velocity dispersions using the Tully-Fisher and Faber-Jackson relations corrected for evolution effects, and calculate, applying the multiple-plane lensing formalism, that SN 1997ff is magnified by 0.34{+-}0.12 mag. Due to the spatial configuration of the foreground galaxies, the shear from individual lenses partially cancels out,and the total distortion induced on the host galaxy is considerably smaller than that produced by a single lens having the same magnification. After correction for lensing, the revised distance to SN 1997ff is m-M = 45.49 {+-} 0.34 mag, which improves the agreement with the {Omega}{sub M} = 0.35, {Omega}{Lambda} = 0.65 cosmology expected from lower-redshift SNe Ia, and is inconsistent at the {approx} 3 sigma confidence level with a uniform gray dust model or a simple evolution model.

  16. The Evolution of Luminous Compact Blue Galaxies: Disks or Spheroids?

    CERN Document Server

    Pisano, D J; Garland, C A; Guzman, R; Castander, F J; Perez-Gallego, J

    2011-01-01

    Luminous compact blue galaxies (LCBGs) are a diverse class of galaxies characterized by high luminosity, blue color, and high surface brightness that sit at the critical juncture of galaxies evolving from the blue to the red sequence. As part of our multi-wavelength survey of local LCBGs, we have been studying the HI content of these galaxies using both single-dish telescopes and interferometers. Our goals are to determine if single-dish HI observations represent a true measure of the dynamical mass of LCBGs and to look for signatures of recent interactions that may be triggering star formation in LCBGs. Our data show that while some LCBGs are undergoing interactions, many appear isolated. While all LCBGs contain HI and show signatures of rotation, the population does not lie on the Tully-Fisher relation nor can it evolve onto it. Furthermore, the HI maps of many LCBGs show signatures of dynamically hot components, suggesting that we are seeing the formation of a thick disk or spheroid in at least some LCBGs....

  17. The Evolution of Luminous Compact Blue Galaxies: Disks or Spheroids?

    CERN Document Server

    Pisano, D J; Rabidoux, K; Wolfe, S; Guzman, R; Perez-Gallego, J; Castander, F J

    2009-01-01

    Luminous compact blue galaxies (LCBGs) are a diverse class of galaxies characterized by high luminosities, blue colors, and high surface brightnesses. Residing at the high luminosity, high mass end of the blue sequence, LCBGs sit at the critical juncture of galaxies that are evolving from the blue to the red sequence. Yet we do not understand what drives the evolution of LCBGs, nor how they will evolve. Based on single-dish HI observations, we know that they have a diverse range of properties. LCBGs are HI-rich with M(HI)=10^{9-10.5} M(sun), have moderate M(dyn)=10^{10-12} M(sun), and 80% have gas depletion timescales less than 3 Gyr. These properties are consistent with LCBGs evolving into low-mass spirals or high mass dwarf ellipticals or dwarf irregulars. However, LCBGs do not follow the Tully-Fisher relation, nor can most evolve onto it, implying that many LCBGs are not smoothly rotating, virialized systems. GMRT and VLA HI maps confirm this conclusion revealing signatures of recent interactions and dynam...

  18. Kinematic Downsizing at z~2

    CERN Document Server

    Simons, Raymond C; Trump, Jonathan R; Weiner, Benjamin J; Heckman, Timothy M; Barro, Guillermo; Koo, David C; Guo, Yicheng; Pacifici, Camilla; Koekemoer, Anton; Stephens, Andrew W

    2016-01-01

    We present results from a survey of the internal kinematics of 49 star-forming galaxies at z$\\,\\sim\\,$2 in the CANDELS fields with the Keck/MOSFIRE spectrograph (SIGMA, Survey in the near-Infrared of Galaxies with Multiple position Angles). Kinematics (rotation velocity $V_{rot}$ and integrated gas velocity dispersion $\\sigma_g$) are measured from nebular emission lines which trace the hot ionized gas surrounding star-forming regions. We find that by z$\\,\\sim\\,$2, massive star-forming galaxies ($\\log\\,M_*/M_{\\odot}\\gtrsim10.2$) have assembled primitive disks: their kinematics are dominated by rotation, they are consistent with a marginally stable disk model, and they form a Tully-Fisher relation. These massive galaxies have values of $V_{rot}/\\sigma_g$ which are factors of 2-5 lower than local well-ordered galaxies at similar masses. Such results are consistent with findings by other studies. We find that low mass galaxies ($\\log\\,M_*/M_{\\odot}\\lesssim10.2$) at this epoch are still in the early stages of disk...

  19. The rotation curves of galaxies at intermediate redshift

    CERN Document Server

    Vogt, N P; Haynes, M P; Courteau, S; Vogt, Nicole P; Herter, Terry; Haynes, Martha P; Courteau, Stephane

    1996-01-01

    We have undertaken a pilot project to measure the rotation velocities of spiral galaxies in the redshift range 0.18 < z < 0.4 using high dispersion long slit spectroscopy obtained with the Palomar 5m telescope. One field galaxy and three cluster objects known to have strong emission lines were observed over wavelength ranges covering the redshifted lines of [OII], CaII K, H beta, and [OIII]. Two of the objects show extended line emission that allows the tracing of the rotation curve in one or more lines. A line width similar to that obtained with single dish telescopes for the 21-cm HI line observed in lower redshift galaxies can be derived from the observed H beta, [OII], and [OIII] emission by measuring a characteristic width from the velocity histogram. These moderately distant galaxies have much stronger emission lines than typical low-redshift spirals but they appear to be kinematically similar. Application of the Tully-Fisher relation suggests that the two galaxies with rotation curves are intrins...

  20. The Dynamical Properties of Virgo Cluster Disk Galaxies

    CERN Document Server

    Ouellette, Nathalie N Q; Holtzman, Jon A; Dalcanton, Julianne J; McDonald, Michael; Zhu, Yucong

    2013-01-01

    By virtue of its proximity, the Virgo Cluster is an ideal laboratory for testing our understanding structure formation in the Universe. In this spirit, we present a dynamical study Virgo galaxies as part of the Spectroscopic and H-band Imaging of Virgo (SHIVir) survey. H$\\alpha$ rotation curves (RC) for our gas-rich galaxies were modelled with a multi-parameter fit function from which various velocity measurements were inferred. Our study takes advantage of archival and our own new data as we aim to compile the largest Tully-Fisher relation (TFR) for a cluster to date. Extended velocity dispersion profiles (VDP) are integrated over varying aperture sizes to extract representative velocity dispersions (VDs) for gas-poor galaxies. Considering the lack of a common standard for the measurement of a fiducial galaxy VD in the literature, we rectify this situation by determining the radius at which the measured VD yields the tightest Fundamental Plane (FP). We found that radius to be at least 1 $R_{\\rm e}$, which ex...

  1. Bayesian 3d velocity field reconstruction with VIRBIuS

    CERN Document Server

    Lavaux, G

    2015-01-01

    I describe a new Bayesian based algorithm to infer the full three dimensional velocity field from observed distances and spectroscopic galaxy catalogues. In addition to the velocity field itself, the algorithm reconstructs true distances, some cosmological parameters and specific non-linearities in the velocity field. The algorithm takes care of selection effects, miscalibration issues and can be easily extended to handle direct fitting of, e.g., the inverse Tully-Fisher relation. I first describe the algorithm in details alongside its performances. This algorithm is implemented in the VIRBIuS (VelocIty Reconstruction using Bayesian Inference Software) software package. I then test it on different mock distance catalogues with a varying complexity of observational issues. The model proved to give robust measurement of velocities for mock catalogues of 3,000 galaxies. I expect the core of the algorithm to scale to tens of thousands galaxies. It holds the promises of giving a better handle on future large and d...

  2. Kinematic Weak Lensing: Forecasts for a Next-Generation Lensing Measurement

    Science.gov (United States)

    Huff, Eric M.; George, M. R.; Krause, E.; Eifler, T.; Schlegel, D. J.

    2014-01-01

    Weak gravitational lensing by cosmic structure is a major science driver for several large ongoing and planned imaging surveys, such as the Dark Energy Survey and the Euclid space mission. Traditionally, lensing in this regime is measured via statistical distortions to the shapes of galaxies. While the cosmological constraining power for a large imaging survey employing this technique is great, the signal itself is noisy, and susceptible to a number of systematic biases. Here we propose a new lensing technique that makes use of the kinematics of disk galaxies and the Tully-Fisher relation. Our method controls for that part of the shape noise which arises from the random orientation of galaxy disks, and promises an increase in signal-to-noise sufficient to bring weak lensing measurements within the reach of the next generation of spectroscopic surveys. We define such a survey here, discuss the advantages and disadvantages, and show that the cosmological constraining power of this kinematic weak lensing method is competitive with the most powerful planned lensing measurements.

  3. Relativity made relatively easy

    CERN Document Server

    Steane, Andrew M

    2012-01-01

    Relativity Made Relatively Easy presents an extensive study of Special Relativity and a gentle (but exact) introduction to General Relativity for undergraduate students of physics. Assuming almost no prior knowledge, it allows the student to handle all the Relativity needed for a university course, with explanations as simple, thorough, and engaging as possible.The aim is to make manageable what would otherwise be regarded as hard; to make derivations as simple as possible and physical ideas as transparent as possible. Lorentz invariants and four-vectors are introduced early on, but tensor not

  4. The LCO/Palomar 10,000 km/sec Cluster Survey; 2, Constraints on Large-Scale Streaming

    CERN Document Server

    Willick, J A

    1998-01-01

    The LCO/Palomar 10,000 km/sec (LP10K) Tully-Fisher (TF) data set is used to test for bulk streaming motions on a ~150 Mpc scale. The sample consists of 172 cluster galaxies in the original target range of the survey, 9000-13,000 km/sec, plus an additional 72 galaxies with cz ~ 150 Mpc.

  5. International relations; Relations internationales

    Energy Technology Data Exchange (ETDEWEB)

    Anon

    2006-05-15

    Seminar relative to the nuclear reactors safety, radioactive waste storage safety, dismantling of nuclear facilities has been organised by W.E.N.R.A. at Brussels in February 2006. Meeting of the French German association for the safety questions of nuclear installations stood in the month of January at Colmar. (N.C.)

  6. The origin of the mu_e - M_B and Kormendy relations in dwarf elliptical galaxies

    CERN Document Server

    Boselli, A; Cortese, L; Gavazzi, G

    2008-01-01

    The present work is aimed at studying the distribution of galaxies of different types and luminosities along different structural scaling relations to see whether massive and dwarf ellipticals have been shaped by the same formation process. This exercise is here done by comparing the distribution of Virgo cluster massive and dwarf ellipticals and star forming galaxies along the B band effective surface brightness and effective radius vs. absolute magnitude relations and the Kormendy relation to the predictions of models tracing the effects of ram-pressure stripping on disc galaxies entering the cluster environment and galaxy harassment. Dwarf ellipticals might have been formed from low luminosity, late-type spirals that recently entered into the cluster and lost their gas because of a ram-pressure stripping event, stopping their activity of star formation. The perturbations induced by the abrupt decrease of the star formation activity are sufficient to modify the structural properties of disc galaxies into th...

  7. Relativity without relativity

    International Nuclear Information System (INIS)

    We give a derivation of general relativity (GR) and the gauge principle that is novel in presupposing neither spacetime nor the relativity principle. We consider a class of actions defined on superspace (the space of Riemannian 3-geometries on a given bare manifold). It has two key properties. The first is symmetry under 3-diffeomorphisms. This is the only postulated symmetry, and it leads to a constraint linear in the canonical momenta. The second property is that the Lagrangian is constructed from a 'local' square root of an expression quadratic in the velocities. The square root is 'local' because it is taken before integration over 3-space. It gives rise to quadratic constraints that do not correspond to any symmetry and are not, in general, propagated by the Euler-Lagrange equations. Therefore these actions are internally inconsistent. However, one action of this form is well behaved: the Baierlein-Sharp-Wheeler (Baierlein R F, Sharp D and Wheeler J A 1962 Phys. Rev. 126 1864) reparametrization-invariant action for GR. From this viewpoint, spacetime symmetry is emergent. It appears as a 'hidden' symmetry in the (underdetermined) solutions of the Euler-Lagrange equations, without being manifestly coded into the action itself. In addition, propagation of the linear diffeomorphism constraint together with the quadratic square-root constraint acts as a striking selection mechanism beyond pure gravity. If a scalar field is included in the configuration space, it must have the same characteristic speed as gravity. Thus Einstein causality emerges. Finally, self-consistency requires that any 3-vector field must satisfy Einstein causality, the equivalence principle and, in addition, the Gauss constraint. Therefore we recover the standard (massless) Maxwell equations

  8. International relations; Relations internationales

    Energy Technology Data Exchange (ETDEWEB)

    Anon

    2009-07-15

    The French nuclear safety authority (A.S.N.) has participated at different meeting in European Union as nuclear decommissioning assistance programme(N.D.A.P.), Regulatory assistance management group (R.A.M.G.) and Instrument for nuclear safety cooperation (I.N.S.C.). The members of Western European nuclear regulator association (W.E.N.R.A.) met and discussed about the future of W.E.N.R.A. and its representativeness and its cooperation with European nuclear safety regulator group (E.N.S.R.E.G.) and head of European radiation control authorities (H.E.R.C.A.). About International relations it is to noticed a meeting at the invitation of IAEA to discuss about the possibility to resort to the Ines scale for medical events. An audit mission under the IAEA aegis stood at Fessenheim, O.S.A.R.T. for operational safety review team. Two years and a half passed by between the audit mission Integrated regulatory review service (I.R.S.S.) welcome by A.S.N. in november 2006 and the audit mission follow up in 2009, 12 experts from 11 different countries and coordinated by three representatives of IAEA worked, the conclusions were that 90% of recommendations made to A.S.N. in 2006 were treated in a satisfying way; the evaluation gives three new recommendations, 7 new suggestions and 11 new correct practices. A meeting of the commission on safety standards (C.S.S.) stood in april 2009. Some others meeting are to be noticed: nuclear safety and security group (N.S.S.G.), expert group on nuclear and radiation safety (E.G.N.R.S.) instituted by the council of the Baltic sea states (C.B.S.S.) treats data exchange on the national networks of dose rates and surveillance of radioactivity in air. International nuclear regulator association (I.N.R.A.) held its first meeting in april 2009 at Seoul (Korea). Bilateral relations with Poland, Italy, Ukraine and Germany planed cooperation or information exchange in the field of nuclear safety. Participation to conference in Usa, meetings with United

  9. The New Numerical Galaxy Catalog (ν2GC): An updated semi-analytic model of galaxy and active galactic nucleus formation with large cosmological N-body simulations

    Science.gov (United States)

    Makiya, Ryu; Enoki, Motohiro; Ishiyama, Tomoaki; Kobayashi, Masakazu A. R.; Nagashima, Masahiro; Okamoto, Takashi; Okoshi, Katsuya; Oogi, Taira; Shirakata, Hikari

    2016-04-01

    We present a new cosmological galaxy formation model, ν2GC, as an updated version of our previous model νGC. We adopt the so-called "semi-analytic" approach, in which the formation history of dark matter halos is computed by N-body simulations, while the baryon physics such as gas cooling, star formation, and supernova feedback are simply modeled by phenomenological equations. Major updates of the model are as follows: (1) the merger trees of dark matter halos are constructed in state-of-the-art N-body simulations, (2) we introduce the formation and evolution process of supermassive black holes and the suppression of gas cooling due to active galactic nucleus (AGN) activity, (3) we include heating of the intergalactic gas by the cosmic UV background, and (4) we tune some free parameters related to the astrophysical processes using a Markov chain Monte Carlo method. Our N-body simulations of dark matter halos have unprecedented box size and mass resolution (the largest simulation contains 550 billion particles in a 1.12 Gpc h-1 box), enabling the study of much smaller and rarer objects. The model was tuned to fit the luminosity functions of local galaxies and mass function of neutral hydrogen. Local observations, such as the Tully-Fisher relation, the size-magnitude relation of spiral galaxies, and the scaling relation between the bulge mass and black hole mass were well reproduced by the model. Moreover, the model also reproduced well the cosmic star formation history and redshift evolution of rest-frame K-band luminosity functions. The numerical catalog of the simulated galaxies and AGNs is publicly available on the web.

  10. THE MOND LIMIT FROM SPACETIME SCALE INVARIANCE

    International Nuclear Information System (INIS)

    The modified Newtonian dynamics (MOND) limit is shown to follow from a requirement of spacetime scale invariance of the equations of motion for nonrelativistic, purely gravitational systems, i.e., invariance of the equations of motion under (t, r) → (λt, λr) in the limit a 0 → ∞. It is suggested that this should replace the definition of the MOND limit based on the low-acceleration behavior of a Newtonian-MOND interpolating function. In this way, the salient, deep-MOND results-asymptotically flat rotation curves, the mass-rotational-speed relation (baryonic Tully-Fisher relation), the Faber-Jackson relation, etc.,-follow from a symmetry principle. For example, asymptotic flatness of rotation curves reflects the fact that radii change under scaling, while velocities do not. I then comment on the interpretation of the deep-MOND limit as one of 'zero mass': rest masses, whose presence obstructs scaling symmetry, become negligible compared to the 'phantom', dynamical masses-those that some would attribute to dark matter. Unlike the former masses, the latter transform in a way that is consistent with the symmetry. Finally, I discuss the putative MOND-cosmology connection in light of another, previously known symmetry of the deep-MOND limit. In particular, it is suggested that MOND is related to the asymptotic de Sitter geometry of our universe. It is conjectured, for example that in an exact de Sitter cosmos, deep-MOND physics would exactly apply to local systems. I also point out, in this connection, the possible relevance of a de Sitter-conformal-field-theory (dS/CFT) duality.

  11. The stellar mass function and efficiency of galaxy formation with a varying initial mass function

    Science.gov (United States)

    McGee, Sean L.; Goto, Ryosuke; Balogh, Michael L.

    2014-03-01

    Several recent observational studies have concluded that the initial mass function (IMF) of stars varies systematically with galaxy properties such as velocity dispersion. In this paper, we investigate the effect of linking the circular velocity of galaxies, as determined from the Fundamental Plane and Tully-Fisher relations, to the slope of the IMF with parametrizations guided by several of these studies. For each empirical relation, we generate stellar masses of ˜600 000 Sloan Digital Sky Survey galaxies at z ˜ 0.1, by fitting the optical photometry to large suites of synthetic stellar populations that sample the full range of galaxy parameters. We generate stellar mass functions and examine the stellar-to-halo mass relations using sub-halo abundance matching. At the massive end, the stellar mass functions become a power law, instead of the familiar exponential decline. As a result, it is a generic feature of these models that the central galaxy stellar-to-halo mass relation is significantly flatter at high masses (slope ˜-0.3 to -0.4) than in the case of a universal IMF (slope ˜-0.6). We find that regardless of whether the IMF varies systematically in all galaxies or just early types, there is still a well-defined peak in the central stellar-to-halo mass ratio at halo masses of ˜1012 M⊙. In general, the IMF variations explored here lead to significantly higher integrated stellar densities if the assumed dependence on circular velocity applies to all galaxies, including late-types; in fact the more extreme cases can be ruled out, as they imply an unphysical situation in which the stellar fraction exceeds the universal baryon fraction.

  12. Relational databases

    CERN Document Server

    Bell, D A

    1986-01-01

    Relational Databases explores the major advances in relational databases and provides a balanced analysis of the state of the art in relational databases. Topics covered include capture and analysis of data placement requirements; distributed relational database systems; data dependency manipulation in database schemata; and relational database support for computer graphics and computer aided design. This book is divided into three sections and begins with an overview of the theory and practice of distributed systems, using the example of INGRES from Relational Technology as illustration. The

  13. Erratum: Precision Velocity Fields in Spiral Galaxies. I. Noncircular Motions and rms Noise in Disks

    Science.gov (United States)

    Beauvais, Charles; Bothun, G.

    2000-05-01

    hypothesis begins to fail). The kinematic disk models are used to find the residual velocity fields, and typical residuals are found to be 10-15 km s-1 over regions 0.5-1.5 kpc in diameter. Correlations are shown to exist between the residual velocity fields and both the Hα intensity and the velocity dispersion images. This suggests that kinematic feedback to the gas from star formation is an important source of noncircular motion. However, the relative quiesence of the large-scale velocity field indicates that the effect does not cause a significant deviation from circular symmetry, kinematically indicating that star formation is not a hidden parameter in the Tully-Fisher relation. Finally, the residual velocity fields are examined for signs of noncircular orbits by looking for azimuthal angular harmonics that would be present if disk galaxies are embedded in a triaxial dark matter potential. For our sample we find the ellipticity of the gas orbits to be round. This is consistent with disks being maximal.

  14. The impact of baryonic physics on the structure of dark matter haloes: the view from the FIRE cosmological simulations

    Science.gov (United States)

    Chan, T. K.; Kereš, D.; Oñorbe, J.; Hopkins, P. F.; Muratov, A. L.; Faucher-Giguère, C.-A.; Quataert, E.

    2015-12-01

    We study the distribution of cold dark matter (CDM) in cosmological simulations from the FIRE (Feedback In Realistic Environments) project, for M* ˜ 104-11 M⊙ galaxies in Mh ˜ 109-12 M⊙ haloes. FIRE incorporates explicit stellar feedback in the multiphase interstellar medium, with energetics from stellar population models. We find that stellar feedback, without `fine-tuned' parameters, greatly alleviates small-scale problems in CDM. Feedback causes bursts of star formation and outflows, altering the DM distribution. As a result, the inner slope of the DM halo profile (α) shows a strong mass dependence: profiles are shallow at Mh ˜ 1010-1011 M⊙ and steepen at higher/lower masses. The resulting core sizes and slopes are consistent with observations. This is broadly consistent with previous work using simpler feedback schemes, but we find steeper mass dependence of α, and relatively late growth of cores. Because the star formation efficiency M*/Mh is strongly halo mass dependent, a rapid change in α occurs around Mh ˜ 1010 M⊙ (M* ˜ 106-107 M⊙), as sufficient feedback energy becomes available to perturb the DM. Large cores are not established during the period of rapid growth of haloes because of ongoing DM mass accumulation. Instead, cores require several bursts of star formation after the rapid build-up has completed. Stellar feedback dramatically reduces circular velocities in the inner kpc of massive dwarfs; this could be sufficient to explain the `Too Big To Fail' problem without invoking non-standard DM. Finally, feedback and baryonic contraction in Milky Way-mass haloes produce DM profiles slightly shallower than the Navarro-Frenk-White profile, consistent with the normalization of the observed Tully-Fisher relation.

  15. GLOBAL STAR FORMATION REVISITED

    International Nuclear Information System (INIS)

    A general treatment of disk star formation is developed from a dissipative multiphase model, with the dominant dissipation due to cloud collisions. The Schmidt-Kennicutt (SK) law emerges naturally for star-forming disks and starbursts. We predict that there should be an inverse correlation between Tully-Fisher law and SK law residuals. The model is extended to include a multiphase treatment of supernova feedback that leads to a turbulent pressure-regulated generalization of the star formation law and is applicable to gas-rich starbursts. Enhanced pressure, as expected in merger-induced star formation, enhances star formation efficiency. An upper limit is derived for the disk star formation rate in starbursts that depends on the ratio of global ISM to cloud pressures. We extend these considerations to the case where the interstellar gas pressure in the inner galaxy is dominated by outflows from a central active galactic nucleus (AGN). During massive spheroid formation, AGN-driven winds trigger star formation, resulting in enhanced supernova feedback and outflows. The outflows are comparable to the AGN-boosted star formation rate and saturate in the super-Eddington limit. Downsizing of both SMBH and spheroids is a consequence of AGN-driven positive feedback. Bondi accretion feeds the central black hole with a specific accretion rate that is proportional to the black hole mass. AGN-enhanced star formation is mediated by turbulent pressure and relates spheroid star formation rate to black hole accretion rate. The relation between black hole mass and spheroid velocity dispersion has a coefficient (Salpeter time to gas consumption time ratio) that provides an arrow of time. Highly efficient, AGN-boosted star formation can occur at high redshift.

  16. Social relations

    DEFF Research Database (Denmark)

    Due, P; Holstein, B; Lund, R;

    1999-01-01

    We introduce a conceptual framework with social relations as the main concept and the structure and the function of social relations as subconcepts. The structure of social relations covers aspects of formal relations and social network. The function of social relations covers social support......,011. The postal questionnaires were answered by a random sample in each of the age groups. The results show marked age and gender differences in both the structure and the function of social relations. The social network, measured as weekly contacts, weakens with age and so does instrumental support. Emotional...... support is unrelated to this decline in contact frequency and appears to be at the same level for younger and older individuals. Relational strain, measured as conflicts, declines with age for all kinds of social relations. The weakening of the social network with age does not seem to affect the level...

  17. Relational Leadership

    DEFF Research Database (Denmark)

    Madsen, Charlotte Øland; Rasmussen, Jørgen Gulddahl

    2015-01-01

    In this chapter, we emphasise what we have outlined as interesting areas of relational leadership and present some ideas on how to facilitate a broader understanding of relational leadership practice. This involves the interpretations that create connections between practice and ontology. We...... elaborate on how leadership in everyday situations can be understood from a relational perspective. The chapter will focus on outlining and inspiring the reader to co-operate with other people to develop further relational understandings of leading....

  18. The Anisotropic Geometrodynamics For Cosmology

    Science.gov (United States)

    Siparov, Sergey V.

    2009-05-01

    The classical geometrodynamics (GRT) and its modern features based on the use of the Fridman-Robertson-Walker type metrics are still unable to explain several important issues of extragalactic observations like flat rotation curves of the spiral galaxies, Tully-Fisher law, globular clusters behavior in comparisson to that of the stars belonging to the galactic plane etc. The chalenging problem of the Universe expansion acceleration stemming from the supernovae observations demands the existence of the repulsion forces which brings one to the choice between the cosmological constant and some quintessence. The popular objects of discussion are now still dark (matter and energy), nevertheless, they are supposed to correspond to more than 95% of the Universe which seems to be far from satisfactory. According to the equivalence principle we can not experimentally distinguish between the inertial forces and the gravitational ones. Since there exist the inertial forces depending on velocity (Coriolis), it seems plausible to explore the velocity dependent gravitational forces. From the mathematical point of view it means that we should use the anisotropic metric. It immediately turns out that the expression for the Einstein-Hilbert action changes in a natural way - contrary to the cases of f(R)-theories, additional scalar fields, arbitrary MOND functions etc.. We use the linear approximation for the metric and derive the generalized geodesics and the equation for the gravity force that contains not only the Newton-Einstein term. The relation between the obtained results and those of Lense-Thirring approach are discussed. The resulting anisotropic geometrodynamics includes all the results of the GRT and is used to give the explanation to the problems mentioned above. One of the impressive consequences is the possibility to explain the observed Hubble red shift not by the Doppler effect as usually but by the gravitational red shift originating from the metric anisotropy.

  19. The Arecibo Pisces-Perseus Survey: An Undergraduate ALFALFA Team Project

    Science.gov (United States)

    O'Donoghue, Aileen A.; Koopmann, Rebecca A.; Haynes, Martha P.; Jones, Michael; Craig, David; Hallenbeck, Gregory L.; Rosenberg, Jessica L.; Venkatesan, Aparna; Undergraduate ALFALFA Team

    2016-01-01

    The Milky Way's position in an outer filament of Lanieakea affords us a striking view of the Pisces-Perseus Supercluster (PPS) arcing roughly from 22h to 4h and 0° to +50° concentrated between cz = 4,000 km/s and cz = 8,000 km/s as a "wall" parallel to the plane of the sky. It is bounded by voids both between Laniakea and PPS and beyond PPS. Within this box, the 70% ALFALFA survey has detected 4,800 galaxies within cz = 8,000 km/s. Of these, 80% have masses greater than 108 M⊙. At the distance of the PPS, galaxies with MHI ≤ 108 M⊙ are below the ALFALFA detection limit. Thus to further explore this rich diversity of galaxy environments and the adjoining voids, the Undergraduate ALFALFA Team is in the process of using the L-band Wide receiver at Arecibo Observatory for the Arecibo Pisces-Perseus Supercluster Survey (APPSS). We will observe galaxies with 108 M⊙ ≤ MHI ≤ 109 M⊙ chosen from the SDSS DR12 and GALEX catalogs. We are limiting our observations to the PPS ridge in 21h 30m to 3h 15m and 23° to 35°. Since this region lacks SDSS spectroscopy, targets have been selected using photometric criteria derived from SDSS and GALEX observations for galaxies detected by ALFALFA. The results of these observations will allow us to constrain the HI mass function along the PPS ridge. Application of the Tully-Fisher relation will allow a robust measure of the infall velocities of galaxies into the filament. This work has been supported by NSF grant AST-1211005.

  20. nIFTY galaxy cluster simulations - III. The similarity and diversity of galaxies and subhaloes

    Science.gov (United States)

    Elahi, Pascal J.; Knebe, Alexander; Pearce, Frazer R.; Power, Chris; Yepes, Gustavo; Cui, Weiguang; Cunnama, Daniel; Kay, Scott T.; Sembolini, Federico; Beck, Alexander M.; Davé, Romeel; February, Sean; Huang, Shuiyao; Katz, Neal; McCarthy, Ian G.; Murante, Giuseppe; Perret, Valentin; Puchwein, Ewald; Saro, Alexandro; Teyssier, Romain

    2016-05-01

    We examine subhaloes and galaxies residing in a simulated Λ cold dark matter galaxy cluster (M^crit_{200}=1.1× 10^{15} h^{-1} M_{⊙}) produced by hydrodynamical codes ranging from classic smooth particle hydrodynamics (SPH), newer SPH codes, adaptive and moving mesh codes. These codes use subgrid models to capture galaxy formation physics. We compare how well these codes reproduce the same subhaloes/galaxies in gravity-only, non-radiative hydrodynamics and full feedback physics runs by looking at the overall subhalo/galaxy distribution and on an individual object basis. We find that the subhalo population is reproduced to within ≲10 per cent for both dark matter only and non-radiative runs, with individual objects showing code-to-code scatter of ≲0.1 dex, although the gas in non-radiative simulations shows significant scatter. Including feedback physics significantly increases the diversity. Subhalo mass and Vmax distributions vary by ≈20 per cent. The galaxy populations also show striking code-to-code variations. Although the Tully-Fisher relation is similar in almost all codes, the number of galaxies with 109 h- 1 M⊙ ≲ M* ≲ 1012 h- 1 M⊙ can differ by a factor of 4. Individual galaxies show code-to-code scatter of ˜0.5 dex in stellar mass. Moreover, systematic differences exist, with some codes producing galaxies 70 per cent smaller than others. The diversity partially arises from the inclusion/absence of active galactic nucleus feedback. Our results combined with our companion papers demonstrate that subgrid physics is not just subject to fine-tuning, but the complexity of building galaxies in all environments remains a challenge. We argue that even basic galaxy properties, such as stellar mass to halo mass, should be treated with errors bars of ˜0.2-0.4 dex.

  1. THE OUTSKIRTS OF GLOBULAR CLUSTERS AS MODIFIED GRAVITY PROBES

    International Nuclear Information System (INIS)

    In the context of theories of gravity modified to account for the observed dynamics of galactic systems without the need to invoke the existence of dark matter, a prediction often appears regarding low-acceleration systems: wherever a falls below a0, one should expect a transition from the classical to the modified gravity regime. This modified gravity regime will be characterized by equilibrium velocities that become independent of distance and that scale with the fourth root of the total baryonic mass, V4∝M. The two conditions above are the well-known flat rotation curves and Tully-Fisher relations of the galactic regime. Recently, however, a similar phenomenology has been hinted at, at the outskirts of Galactic globular clusters, precisely in the region where a 0. Radial profiles of the projected velocity dispersion have been observed to stop decreasing along Keplerian expectations and to level off at constant values beyond the radii where a 0. We have constructed gravitational equilibrium dynamical models for a number of globular clusters for which the above gravitational anomaly has been reported, using a modified Newtonian force law that yields equilibrium velocities equivalent to modified Newtonian dynamics. We find models having an inner Newtonian region and an outer modified gravity regime, which reproduce all observational constraints, surface brightness profiles, total masses, and line-of-sight velocity dispersion profiles, can be easily constructed. Through the use of detailed single stellar population models tuned individually to each of the globular clusters in question, we derive estimates of the total masses for these systems. Interestingly, we find that the asymptotic values of the velocity dispersion profiles are consistent with scaling with the fourth root of the total masses, as expected under modified gravity scenarios.

  2. Cosmic flows and the expansion of the local Universe from non-linear phase-space reconstructions

    Science.gov (United States)

    Heß, Steffen; Kitaura, Francisco-Shu

    2016-03-01

    In this work, we investigate the impact of cosmic flows and density perturbations on Hubble constant H0 measurements using non-linear phase-space reconstructions of the Local Universe (LU). In particular, we rely on a set of 25 precise constrained N-body simulations based on Bayesian initial conditions reconstructions of the LU using the Two-Micron Redshift Survey galaxy sample within distances of about 90 h-1 Mpc. These have been randomly extended up to volumes enclosing distances of 360 h-1 Mpc with augmented Lagrangian perturbation theory (750 simulations in total), accounting in this way for gravitational mode coupling from larger scales, correcting for periodic boundary effects, and estimating systematics of missing attractors (σlarge = 134 s-1 km). We report on Local Group (LG) speed reconstructions, which for the first time are compatible with those derived from cosmic microwave background-dipole measurements: |vLG| = 685 ± 137 s-1 km. The direction (l, b) = (260.5° ± 13.3°, 39.1 ± 10.4°) is found to be compatible with the observations after considering the variance of large scales. Considering this effect of large scales, our local bulk flow estimations assuming a Λ cold dark matter model are compatible with the most recent estimates based on velocity data derived from the Tully-Fisher relation. We focus on low-redshift supernova measurements out to 0.01 positive bias in H0. Taking these effects into account yields a correction of ΔH0 = -1.76 ± 0.21 s- 1 km Mpc- 1, thereby reducing the tension between local probes and more distant probes. Effectively H0 is lower by about 2 per cent.

  3. Introducing the Illustris Project: simulating the coevolution of dark and visible matter in the Universe

    Science.gov (United States)

    Vogelsberger, Mark; Genel, Shy; Springel, Volker; Torrey, Paul; Sijacki, Debora; Xu, Dandan; Snyder, Greg; Nelson, Dylan; Hernquist, Lars

    2014-10-01

    We introduce the Illustris Project, a series of large-scale hydrodynamical simulations of galaxy formation. The highest resolution simulation, Illustris-1, covers a volume of (106.5 Mpc)3, has a dark mass resolution of 6.26 × 106 M⊙, and an initial baryonic matter mass resolution of 1.26 × 106 M⊙. At z = 0 gravitational forces are softened on scales of 710 pc, and the smallest hydrodynamical gas cells have an extent of 48 pc. We follow the dynamical evolution of 2 × 18203 resolution elements and in addition passively evolve 18203 Monte Carlo tracer particles reaching a total particle count of more than 18 billion. The galaxy formation model includes: primordial and metal-line cooling with self-shielding corrections, stellar evolution, stellar feedback, gas recycling, chemical enrichment, supermassive black hole growth, and feedback from active galactic nuclei. Here we describe the simulation suite, and contrast basic predictions of our model for the present-day galaxy population with observations of the local universe. At z = 0 our simulation volume contains about 40 000 well-resolved galaxies covering a diverse range of morphologies and colours including early-type, late-type and irregular galaxies. The simulation reproduces reasonably well the cosmic star formation rate density, the galaxy luminosity function, and baryon conversion efficiency at z = 0. It also qualitatively captures the impact of galaxy environment on the red fractions of galaxies. The internal velocity structure of selected well-resolved disc galaxies obeys the stellar and baryonic Tully-Fisher relation together with flat circular velocity curves. In the well-resolved regime, the simulation reproduces the observed mix of early-type and late-type galaxies. Our model predicts a halo mass dependent impact of baryonic effects on the halo mass function and the masses of haloes caused by feedback from supernova and active galactic nuclei.

  4. Third-epoch Magellanic Cloud proper motions. II. The large Magellanic Cloud rotation field in three dimensions

    International Nuclear Information System (INIS)

    We present the first detailed assessment of the large-scale rotation of any galaxy based on full three-dimensional velocity measurements. We do this for the LMC by combining our Hubble Space Telescope average proper motion (PM) measurements for stars in 22 fields, with existing line-of-sight (LOS) velocity measurements for 6790 individual stars. We interpret these data with a model of circular rotation in a flat disk. The PM and LOS data paint a consistent picture of the LMC rotation, and their combination yields several new insights. The PM data imply a stellar dynamical center that coincides with the H I dynamical center, and a rotation curve amplitude consistent with that inferred from LOS velocity studies. The implied disk viewing angles agree with the range of values found in the literature, but continue to indicate variations with stellar population and/or radius. Young (red supergiant) stars rotate faster than old (red and asymptotic giant branch) stars due to asymmetric drift. Outside the central region, the circular velocity is approximately flat at V circ = 91.7 ± 18.8 km s–1. This is consistent with the baryonic Tully-Fisher relation and implies an enclosed mass M(8.7 kpc) = (1.7 ± 0.7) × 1010 M ☉. The virial mass is larger, depending on the full extent of the LMC's dark halo. The tidal radius is 22.3 ± 5.2 kpc (24.°0 ± 5.°6). Combination of the PM and LOS data yields kinematic distance estimates for the LMC, but these are not yet competitive with other methods.

  5. Alfalfa discovery of the nearby gas-rich dwarf galaxy LEO P. V. Neutral gas dynamics and kinematics

    International Nuclear Information System (INIS)

    We present new H I spectral line imaging of the extremely metal-poor, star-forming dwarf irregular galaxy Leo P. Our H I images probe the global neutral gas properties and the local conditions of the interstellar medium (ISM). The H I morphology is slightly elongated along the optical major axis. We do not find obvious signatures of interaction or infalling gas at large spatial scales. The neutral gas disk shows obvious rotation, although the velocity dispersion is comparable to the rotation velocity. The rotation amplitude is estimated to be V c =15 ± 5 km s–1. Within the H I radius probed by these observations, the mass ratio of gas to stars is roughly 2:1, while the ratio of the total mass to the baryonic mass is ≳15:1. We use this information to place Leo P on the baryonic Tully-Fisher relation, testing the baryonic content of cosmic structures in a sparsely populated portion of parameter space that has hitherto been occupied primarily by dwarf spheroidal galaxies. We detect the signature of two temperature components in the neutral ISM of Leo P; the cold and warm components have characteristic velocity widths of 4.2 ± 0.9 km s–1 and 10.1 ± 1.2 km s–1, corresponding to kinetic temperature upper limits of ∼1100 K and ∼6200 K, respectively. The cold H I component is unresolved at a physical resolution of 200 pc. The highest H I surface densities are observed in close physical proximity to the single H II region. A comparison of the neutral gas properties of Leo P with other extremely metal-deficient (XMD) galaxies reveals that Leo P has the lowest neutral gas mass of any known XMD, and that the dynamical mass of Leo P is more than two orders of magnitude smaller than any known XMD with comparable metallicity.

  6. Relative exchangeability with equivalence relations

    OpenAIRE

    Crane, Harry; Towsner, Henry

    2016-01-01

    We describe an Aldous--Hoover-type characterization of random relational structures that are exchangeable relative to a fixed structure which may have various equivalence relations. Our main theorem gives the common generalization of the results on relative exchangeability due to Ackerman \\cite{Ackerman2015} and Crane and Towsner \\cite{CraneTowsner2015} and hierarchical exchangeability results due to Austin and Panchenko \\cite{AustinPanchenko2014}.

  7. Quantum Relativity

    OpenAIRE

    Ionescu, Lucian M

    2010-01-01

    Quantum Relativity is supposed to be a new theory, which locally is a deformation of Special Relativity, and globally it is a background independent theory including the main ideas of General Relativity, with hindsight from Quantum Theory. The qubit viewed as a Hopf monopole bundle is considered as a unifying gauge "group". Breaking its chiral symmetry is conjectured to yield gravity as a deformation of electromagnetism. It is already a quantum theory in the context of Quantum Information Dyn...

  8. New lessons from the H I size-mass relation of galaxies

    Science.gov (United States)

    Wang, Jing; Koribalski, Bärbel S.; Serra, Paolo; van der Hulst, Thijs; Roychowdhury, Sambit; Kamphuis, Peter; Chengalur, Jayaram N.

    2016-08-01

    We revisit the H I size-mass (D_{H I}-MH I) relation of galaxies with a sample of more than 500 nearby galaxies covering over five orders of magnitude in H I mass and more than 10 B-band magnitudes. The relation is remarkably tight with a scatter σ ˜ 0.06 dex, or 14 per cent. The scatter does not change as a function of galaxy luminosity, H I richness or morphological type. The relation is linked to the fact that dwarf and spiral galaxies have a homogeneous radial profile of H I surface density in the outer regions when the radius is normalized by DH I. The early-type disc galaxies typically have shallower H I radial profiles, indicating a different gas accretion history. We argue that the process of atomic-to-molecular gas conversion or star formation cannot explain the tightness of the DH I-MH I relation. This simple relation puts strong constraints on simulation models for galaxy formation.

  9. New Lessons from the HI Size-Mass Relation of Galaxies

    CERN Document Server

    Wang, Jing; Serra, Paolo; van der Hulst, Thijs; Roychowdhury, Sambit; Kamphuis, Peter; Chengalur, Jayaram N

    2016-01-01

    We revisit the HI size-mass (D$_{\\rm HI}$-M$_{\\rm HI}$) relation of galaxies with a sample of more than 500 nearby galaxies covering over five orders of magnitude in HI mass and more than ten $B$-band magnitudes. The relation is remarkably tight with a scatter $\\sigma \\sim$0.06 dex, or 14%. The scatter does not change as a function of galaxy luminosity, HI richness or morphological type. The relation is linked to the fact that dwarf and spiral galaxies have a homogenous radial profile of HI surface density in the outer regions when the radius is normalised by D$_{\\rm HI}$. The early-type disk galaxies typically have shallower HI radial profiles, indicating a different gas accretion history. We argue that the process of atomic-to-molecular gas conversion or star formation cannot explain the tightness of the D$_{\\rm HI}$-M$_{\\rm HI}$ relation. This simple relation puts strong constraints on simulation models for galaxy formation.

  10. Numerical Relativity

    Science.gov (United States)

    Baker, John G.

    2009-01-01

    Recent advances in numerical relativity have fueled an explosion of progress in understanding the predictions of Einstein's theory of gravity, General Relativity, for the strong field dynamics, the gravitational radiation wave forms, and consequently the state of the remnant produced from the merger of compact binary objects. I will review recent results from the field, focusing on mergers of two black holes.

  11. A relativistic description of MOND using the Palatini formalism in an extended metric theory of gravity

    CERN Document Server

    Barrientos, E

    2016-01-01

    We construct a relativistic metric description of MOND using the Palatini formalism following the \\( f(\\chi)=\\chi^b \\) description of \\citet{mendozatula}. We show that in order to recover the non-relativistic MOND regime where, for circular orbits the Tully-Fisher law replaces Kepler's third law, the value of the parameter $ b = 3/2 $, which is coincident with the value found using a pure metric formalism Capozziello et al. (2011). Unlike the pure metric formalism, which yields 4th order field equations, the Palatini approach yields second order field equations, which is a desirable requirement from a theoretical perspective. Thus, the phenomenology associated to astrophysical phenomena with Tully-Fisher scalings can be accounted for using this proposal, without the need to introduce any non-baryonic dark matter particles.

  12. Relative Egalitarianism and Related Criteria

    OpenAIRE

    Sprumont, Yves

    2009-01-01

    We reconsider the problem of aggregating individual preference orderings into a single social ordering when alternatives are lotteries and individual preferences are of the von Neumann-Morgenstern type. Relative egalitarianism ranks alternatives by applying the leximin ordering to the distributions of (0-1) normalized utilities they generate. We propose an axiomatic characterization of this aggregation rule and discuss related criteria.

  13. Relational Leading

    DEFF Research Database (Denmark)

    Larsen, Mette Vinther; Rasmussen, Jørgen Gulddahl

    2015-01-01

    This first chapter presents the exploratory and curious approach to leading as relational processes – an approach that pervades the entire book. We explore leading from a perspective that emphasises the unpredictable challenges and triviality of everyday life, which we consider an interesting......, relevant and realistic way to examine leading. The chapter brings up a number of concepts and contexts as formulated by researchers within the field, and in this way seeks to construct a first understanding of relational leading....

  14. An Atlas for Structural Studies of Spiral Galaxies

    OpenAIRE

    Courteau, Stephane

    1999-01-01

    This is an announcement of a new database of structural properties for 304 late-type (Sb-Sc) spiral galaxies drawn from the UGC catalogue. These data were compiled from the kinematic and photometric studies of Courteau (1996, 1997), and are made available to the community via the Canadian Astronomy Data Centre. The data base contains redshift information and Tully-Fisher distances, various measures of optical (Halpha) line width and rotational velocity, isophotal diameters and magnitudes, dis...

  15. Relational Syllogistics

    CERN Document Server

    Ivanov, Nikolay

    2011-01-01

    We present a quantifier-free Hilbert-style axiomatization of a system of relational syllogistic formalizing the following binary relations between classes (of objects): $a\\leq b\\leftrightarrow_{def} (\\forall x)(x\\in a\\rightarrow x\\in b)$ and $(a,b)[\\alpha]\\leftrightarrow_{def} (Q_{1} x\\in a)(Q_{2}y\\in b)(x,y)\\in R(\\alpha)$, where $a,b$ denote arbitrary classes, $Q_{1},Q_{2}\\in\\{\\forall,\\exists\\}$ and $\\alpha$ denotes arbitrary binary relation between objects. The main result of the paper is the completeness theorem with respect to the intended semantics and the computational complexity of the satisfiability problem.

  16. Relative thermalization

    Science.gov (United States)

    del Rio, Lídia; Hutter, Adrian; Renner, Renato; Wehner, Stephanie

    2016-08-01

    Locally thermal quantum systems may contradict traditional thermodynamics: heat can flow from a cold body to a hotter one, if the two are highly entangled. We show that to recover thermodynamic laws, we must use a stronger notion of thermalization: a system S is thermal relative to a reference R if S is both locally thermal and uncorrelated with R . Considering a general quantum reference is particularly relevant for a thermodynamic treatment of nanoscale quantum systems. We derive a technical condition for relative thermalization in terms of conditional entropies. Established results on local thermalization, which implicitly assume a classical reference, follow as special cases.

  17. Readable relativity

    CERN Document Server

    Durell, Clement V

    2003-01-01

    Concise and practical, this text by a renowned teacher sketches the mathematical background essential to understanding the fundamentals of relativity theory. Subjects include the velocity of light, measurement of time and distance, and properties of mass and momentum, with numerous diagrams, formulas, and examples, plus exercises and solutions. 1960 edition.

  18. International relations

    International Nuclear Information System (INIS)

    Seminar relative to the nuclear reactors safety, radioactive waste storage safety, dismantling of nuclear facilities has been organised by W.E.N.R.A. at Brussels in February 2006. Meeting of the French German association for the safety questions of nuclear installations stood in the month of January at Colmar. (N.C.)

  19. Relativizing relativity

    OpenAIRE

    Svozil, Karl

    1998-01-01

    Special relativity theory is generalized to two or more ``maximal'' signalling speeds. This framework is discussed in three contexts: (i) as a scenario for superluminal signalling and motion, (ii) as the possibility of two or more ``light'' cones due to the a ``birefringent'' vaccum, and (iii) as a further extension of conventionality beyond synchrony.

  20. GAMA/H-ATLAS: The Dust Opacity - Stellar Mass Surface Density Relation for Spiral Galaxies

    CERN Document Server

    Grootes, M W; Popescu, C C; Pastrav, B; Andrae, E; Gunawardhana, M; Kelvin, L S; Liske, J; Seibert, M; Taylor, E N; Graham, A W; Baes, M; Baldry, I K; Bourne, N; Brough, S; Cooray, A; Dariush, A; De Zotti, G; Driver, S P; Dunne, L; Gomez, H; Hopkins, A M; Hopwood, R; Jarvis, M; Loveday, J; Maddox, S; Madore, B F; Michałowski, M J; Norberg, P; Parkinson, H R; Prescott, M; Robotham, A S G; Smith, D J B; Thomas, D; Valiante, E

    2013-01-01

    We report the discovery of a well-defined correlation between B-band face-on central optical depth due to dust, \\tau^f_B, and the stellar mass surface density, \\mu_{*}, of nearby (z < 0.13) spiral galaxies: log(\\tau^f_B) = 1.12(+-0.11)log(\\mu_{*}/M_sol kpc^2)-8.6(+-0.8). This relation was derived from a sample of spiral galaxies taken from the Galaxy and Mass Assembly (GAMA) survey and detected in the FIR/submm in the Herschel-ATLAS survey. Using a quantitative analysis of the NUV attenuation-inclination relation for complete samples of GAMA spirals categorized according to \\mu_{*} we demonstrate that this correlation can be used to statistically correct for dust attenuation purely on the basis of optical photometry and S'ersic-profile morphological fits. Considered together with previously established empirical relationships between stellar mass, metallicity and gas mass, the near linearity and high constant of proportionality of the \\tau^f_B-\\mu_{*} relation disfavors a stellar origin for the bulk of ref...

  1. Distant Relations

    DEFF Research Database (Denmark)

    Søndergaard, Morten

    2011-01-01

    contribute to and learn from entrepreneurship research. In a number of workshops sponsored by the Knowledge Foundation and the Bank of Sweden Tercentenary Foundation, a group of international scholars, practicing artists, and representatives of funding organizations have addressed issues such as opportunity......) Entrepreneurship on the art arena - An ecological perspective (Mikael Scherdin and Ivo Zander) Distant relations - Art practice in a global culture (Morten Søndergaard) Art entrepreneurship - A commentary (Daved Barry) Summary and policy implications (Mikael Scherdin and Ivo Zander)...

  2. Public relations

    International Nuclear Information System (INIS)

    At Nuclear Regulatory Authority of the Slovak Republic (NRA SR), the public relations belongs to the secretariat of the Chairman, and are a part of the policy of carefully planned and purposeful efforts to establish mutual relations between the authority and the public. A spokesmen of NRA SR is in charge of the public relations. The spokesman is ready, without a useless filibuster and based on a particular requirement, to inform governmental bodies, other national bodies and organizations, embassies and international organizations, the public and news media in case of an event at a nuclear installation. To provide for communications activities, NRA SR constructed and opened the Information centre with a particular equipment in autumn 1995, that has already started communications with some dailies, broadcasting, television and Press Agency SR. It has been envisaged that there will be press conferences held in the Information centre a few times a year, or NRA SR senior staff may be interviewed here on extraordinary events at NPPs, or on some other important occasions in NRA SR. In 1995, NRA Sr issued the Annual report in a few variants - each suitable for different use - on NRA SR activities and nuclear safety of Slovak nuclear power plants as of 1994. The NRA SR's Bulletin has started to be published with periodicity of 3 times a year, focusing on NRA SR activities both in Slovakia and abroad. NRA SR Information centre provides foreign visitors with independent propagation and information materials about the issue of nuclear safety enhancement at operational Slovak NPPs. Furthermore, the Information centre provides both the NRA SR's residences in Bratislava and Trnava with daily press monitoring of topical news

  3. Thermal Relativity

    Institute of Scientific and Technical Information of China (English)

    赵柳

    2011-01-01

    The group G of general coordinate transformations on the thermodynamic configuration space ε spanned by all the extensive variables keeps the first law of thermodynamics invariant. One can introduce a metric with Lorentzian signature on the space ε, with the corresponding line element also being invariant under the action of G. This line element is identi6ed as the square of the proper entropy. Thus the second law of thermodynamics is also formulated invariantly and this lays down the foundation for the principle of thermal relativity.

  4. General Relativity

    CERN Document Server

    Canuto, V

    2015-01-01

    This is an English translation of the Italian version of an encyclopedia chapter that appeared in the Italian Encyclopedia of the Physical Sciences, edited by Bruno Bertotti (1994). Following requests from colleagues we have decided to make it available to a more general readership. We present the motivation for constructing General Relativity, provide a short discussion of tensor algebra, and follow the set up of Einstein equations. We discuss briefly the initial value problem, the linear approximation and how should non gravitational physics be described in curved spacetime.

  5. Special relativity

    CERN Document Server

    Faraoni, Valerio

    2013-01-01

    This book offers an essential bridge between college-level introductions and advanced graduate-level books on special relativity. It begins at an elementary level, presenting and discussing the basic concepts normally covered in college-level works, including the Lorentz transformation. Subsequent chapters introduce the four-dimensional worldview implied by the Lorentz transformations, mixing time and space coordinates, before continuing on to the formalism of tensors, a topic usually avoided in lower-level courses. The book’s second half addresses a number of essential points, including the concept of causality; the equivalence between mass and energy, including applications; relativistic optics; and measurements and matter in Minkowski spacetime. The closing chapters focus on the energy-momentum tensor of a continuous distribution of mass-energy and its covariant conservation; angular momentum; a discussion of the scalar field of perfect fluids and the Maxwell field; and general coordinates. Every chapter...

  6. International relations

    International Nuclear Information System (INIS)

    The French nuclear safety authority (A.S.N.) has participated at different meeting in European Union as nuclear decommissioning assistance programme(N.D.A.P.), Regulatory assistance management group (R.A.M.G.) and Instrument for nuclear safety cooperation (I.N.S.C.). The members of Western European nuclear regulator association (W.E.N.R.A.) met and discussed about the future of W.E.N.R.A. and its representativeness and its cooperation with European nuclear safety regulator group (E.N.S.R.E.G.) and head of European radiation control authorities (H.E.R.C.A.). About International relations it is to noticed a meeting at the invitation of IAEA to discuss about the possibility to resort to the Ines scale for medical events. An audit mission under the IAEA aegis stood at Fessenheim, O.S.A.R.T. for operational safety review team. Two years and a half passed by between the audit mission Integrated regulatory review service (I.R.S.S.) welcome by A.S.N. in november 2006 and the audit mission follow up in 2009, 12 experts from 11 different countries and coordinated by three representatives of IAEA worked, the conclusions were that 90% of recommendations made to A.S.N. in 2006 were treated in a satisfying way; the evaluation gives three new recommendations, 7 new suggestions and 11 new correct practices. A meeting of the commission on safety standards (C.S.S.) stood in april 2009. Some others meeting are to be noticed: nuclear safety and security group (N.S.S.G.), expert group on nuclear and radiation safety (E.G.N.R.S.) instituted by the council of the Baltic sea states (C.B.S.S.) treats data exchange on the national networks of dose rates and surveillance of radioactivity in air. International nuclear regulator association (I.N.R.A.) held its first meeting in april 2009 at Seoul (Korea). Bilateral relations with Poland, Italy, Ukraine and Germany planed cooperation or information exchange in the field of nuclear safety. Participation to conference in Usa, meetings with United

  7. Spatial Relation Resolution and Spatial Relation Abstraction

    Institute of Scientific and Technical Information of China (English)

    AI Tinghua; LIU Yaolin

    2003-01-01

    This paper attempts toregard spatial relation transformationas an important process in map gener-alization. The spatial relation generali-zation can be divided into the compo-nents of abstraction: topology, dis-tance and orientation. The concept‘ spatial relation resolution' is intro-duced to describe the constraints ofrelative spatial relation. On the basisof nine intersection models, the cardi-nal direction models and the iso-dis-tance-relation models, this paper givesthree sorts of relation resolution repre-sentations for topological, distance andorientation relation, respectively. Twomapping implementations in map gen-eralization is discussed.

  8. Relative Derived Equivalences and Relative Homological Dimensions

    Institute of Scientific and Technical Information of China (English)

    Sheng Yong PAN

    2016-01-01

    Let A be a small abelian category. For a closed subbifunctor F of Ext1A (−,−), Buan has generalized the construction of Verdier’s quotient category to get a relative derived category, where he localized with respect to F-acyclic complexes. In this paper, the homological properties of relative derived categories are discussed, and the relation with derived categories is given. For Artin algebras, using relative derived categories, we give a relative version on derived equivalences induced by F-tilting complexes. We discuss the relationships between relative homological dimensions and relative derived equivalences.

  9. The local black hole mass function derived from the M_{BH}-P and the M_{BH}-n relations

    CERN Document Server

    Pakdil, Burcin Mutlu; Davis, Benjamin L

    2016-01-01

    We present a determination of the supermassive black hole (SMBH) mass function for early- and late-type galaxies in the nearby universe (z<0.0057), established from a volume-limited sample consisting of a statistically complete collection of the brightest spiral galaxies in the southern hemisphere. The sample is defined by limiting luminosity (redshift-independent) distance, D_L=25.4 Mpc, and a limiting absolute B-band magnitude, M_B=-19.12. These limits define a sample of 140 spiral, 30 elliptical (E), and 38 lenticular (S0) galaxies. We established the Sersic index distribution for early-type (E/S0) galaxies in our sample. Davis et al. (2014) established the pitch angle distribution for their sample, which is identical to our late-type (spiral) galaxy sample. We then used the pitch angle and the Sersic index distributions in order to estimate the SMBH mass function for our volume-limited sample. The observational simplicity of our approach relies on the empirical relation between the mass of the central ...

  10. H I CONTENT AND OPTICAL PROPERTIES OF FIELD GALAXIES FROM THE ALFALFA SURVEY. II. MULTIVARIATE ANALYSIS OF A GALAXY SAMPLE IN LOW-DENSITY ENVIRONMENTS

    International Nuclear Information System (INIS)

    This is the second paper of two reporting results from a study of the H I content and stellar properties of nearby galaxies detected by the Arecibo Legacy Fast ALFA blind 21 cm line survey and the Sloan Digital Sky Survey in a 2160 deg2 region of high galactic latitude sky covered by both surveys, in the general Virgo direction. Here, we analyze a complete H I flux-limited subset of 1624 objects with homogeneously measured 21 cm and multi-wavelength optical attributes extracted from the control sample of H I emitters in environments of low local galactic density assembled by Toribio et al. (Paper I). Strategies of multivariate data analysis are applied to this data set in order to (i) investigate the correlation structure of the space defined by an extensive set of potentially independent observables describing gas-rich systems, (ii) identify the intrinsic parameters that best define their neutral gas content, and (iii) explore the scaling relations arising from the joint distributions of the quantities most strongly correlated with the H I mass. The principal component analysis performed over a set of five galaxy properties reveals that they are strongly interrelated, supporting previous claims that nearby H I emitters show a high degree of correlation. The best predictors for the expected value of MHI are the diameter of the stellar disk, D25,r, followed by the total luminosity (both in the r band), and the maximum rotation speed, while morphological proxies such as color show only a moderately strong correlation with the gaseous content attenuated by observational error. Among the various inferred prescriptions, the simplest and most accurate is log(MHI/Msun) = 8.72 + 1.25 log(D25,r/kpc). We find a slope of -8.2 ± 0.5 for the relation between optical magnitude and log rotation speed, in good agreement with Tully-Fisher studies, as well as a log slope of 1.55 ± 0.06 for the H I mass-optical galaxy size relation. Given the homogeneity of the measurements and the

  11. How supernova explosions power galactic winds

    Science.gov (United States)

    Creasey, Peter; Theuns, Tom; Bower, Richard G.

    2013-03-01

    mass loading depends on circular velocity as β∝V- αd with α ≈ 2.5 for a model which fits the Tully-Fisher relation. Such a scaling is often assumed in phenomenological models of galactic winds in order to reproduce the flat faint end slope of the mass function. Our normalization is in approximate agreement with observed estimates of the mass loading for the Milky Way. The scaling we find sets the investigation of galaxy winds on a new footing, providing a physically motivated subgrid description of winds that can be implemented in cosmological hydrodynamic simulations and phenomenological models.

  12. Social relations: network, support and relational strain

    DEFF Research Database (Denmark)

    Due, P; Holstein, B; Lund, Rikke;

    1999-01-01

    We introduce a conceptual framework with social relations as the main concept and the structure and the function of social relations as subconcepts. The structure of social relations covers aspects of formal relations and social network. The function of social relations covers social support...... postal questionnaires were answered by a random sample in each of the age groups. The results show marked age and gender differences in both the structure and the function of social relations. The social network, measured as weekly contacts, weakens with age and so does instrumental support. Emotional...... support is unrelated to this decline in contact frequency and appears to be at the same level for younger and older individuals. Relational strain, measured as conflicts, declines with age for all kinds of social relations. The weakening of the social network with age does not seem to affect the level of...

  13. Visualizing relativity: The OpenRelativity project

    Science.gov (United States)

    Sherin, Zachary W.; Cheu, Ryan; Tan, Philip; Kortemeyer, Gerd

    2016-05-01

    We present OpenRelativity, an open-source toolkit to simulate effects of special relativity within the popular Unity game engine. Intended for game developers, educators, and anyone interested in physics, OpenRelativity can help people create, test, and share experiments to explore the effects of special relativity. We describe the underlying physics and some of the implementation details of this toolset with the hope that engaging games and interactive relativistic "laboratory" experiments might be implemented.

  14. The MOSDEF Survey: Dynamical and Baryonic Masses and Kinematic Structures of Star-forming Galaxies at 1.4 ≤ z ≤ 2.6

    Science.gov (United States)

    Price, Sedona H.; Kriek, Mariska; Shapley, Alice E.; Reddy, Naveen A.; Freeman, William R.; Coil, Alison L.; de Groot, Laura; Shivaei, Irene; Siana, Brian; Azadi, Mojegan; Barro, Guillermo; Mobasher, Bahram; Sanders, Ryan L.; Zick, Tom

    2016-03-01

    We present {{H}}α gas kinematics for 178 star-forming galaxies at z˜ 2 from the MOSFIRE Deep Evolution Field survey. We have developed models to interpret the kinematic measurements from fixed-angle multi-object spectroscopy, using structural parameters derived from Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey Hubble Space Telescope/F160W imaging. For 35 galaxies, we measure resolved rotation with a median of {(V/{σ }V,0)}{RE} = 2.1. We derive dynamical masses from the kinematics and sizes and compare them to baryonic masses, with gas masses estimated from dust-corrected {{H}}α star formation rates (SFRs) and the Kennicutt-Schmidt relation. When assuming that galaxies with and without observed rotation have the same median {(V/{σ }V,0)}{RE}, we find good agreement between the dynamical and baryonic masses, with a scatter of {σ }{rms} = 0.34 {dex} and a median offset of {{Δ }}{{log}}10 M = 0.04 {dex}. This comparison implies a low dark matter fraction (8% within an effective radius) for a Chabrier initial mass function (IMF), and disfavors a Salpeter IMF. Moreover, the requirement that {M}{dyn}/{M}{baryon} should be independent of inclination yields a median value of {(V/{σ }V,0)}{RE} = 2.1 for galaxies without observed rotation. If, instead, we treat the galaxies without detected rotation as early-type galaxies, the masses are also in reasonable agreement ({{Δ }}{{log}}10 M = -0.07 {dex}, {σ }{rms} = 0.37 {dex}). The inclusion of gas masses is critical in this comparison; if gas masses are excluded, there is an increasing trend of {M}{dyn}/{M}* with higher specific SFR (SSFR). Furthermore, we find indications that V/σ decreases with increasing {{H}}α SSFR for our full sample, which may reflect disk settling. We also study the Tully-Fisher relation and find that at fixed stellar mass {S}0.5 = {(0.5{V}2.22+{σ }V,02)}1/2 was higher at earlier times. At fixed baryonic mass, we observe the opposite trend. Finally, the baryonic and

  15. DARK AND LUMINOUS MATTER IN THINGS DWARF GALAXIES

    International Nuclear Information System (INIS)

    We present mass models for the dark matter component of seven dwarf galaxies taken from 'The H I Nearby Galaxy Survey' (THINGS) and compare these with those taken from numerical Λ cold dark matter (ΛCDM) simulations. The THINGS high-resolution data significantly reduce observational uncertainties and thus allow us to derive accurate dark matter distributions in these systems. We here use the bulk velocity fields when deriving the rotation curves of the galaxies. Compared to other types of velocity fields, the bulk velocity field minimizes the effect of small-scale random motions more effectively and traces the underlying kinematics of a galaxy more properly. The 'Spitzer Infrared Nearby Galaxies Survey' 3.6 μm and ancillary optical data are used for separating the baryons from their total matter content in the galaxies. The sample dwarf galaxies are found to be dark matter dominated over most radii. The relation between total baryonic (stars + gas) mass and maximum rotation velocity of the galaxies is roughly consistent with the baryonic Tully-Fisher relation calibrated from a larger sample of gas-dominated low-mass galaxies. We find discrepancies between the derived dark matter distributions of the galaxies and those of ΛCDM simulations, even after corrections for non-circular motions have been applied. The observed solid body-like rotation curves of the galaxies rise too slowly to reflect the cusp-like dark matter distribution in cold dark matter halos. Instead, they are better described by core-like models such as pseudo-isothermal halo models dominated by a central constant-density core. The mean value of the logarithmic inner slopes of the mass density profiles is α = -0.29 ± 0.07. They are significantly different from the steep slope of ∼ - 1.0 inferred from previous dark-matter-only simulations, and are more consistent with shallower slopes found in recent ΛCDM simulations of dwarf galaxies in which the effects of baryonic feedback processes are

  16. Neutrosophic Relational Database Decomposition

    OpenAIRE

    Meena Arora; Ranjit Biswas; Dr. U.S.Pandey

    2011-01-01

    In this paper we present a method of decomposing a neutrosophic database relation with Neutrosophic attributes into basic relational form. Our objective is capable of manipulating incomplete as well as inconsistent information. Fuzzy relation or vague relation can only handle incomplete information. Authors are taking the Neutrosophic Relational database [8],[2] to show how imprecise data can be handled in relational schema.

  17. Alfalfa discovery of the nearby gas-rich dwarf galaxy LEO P. V. Neutral gas dynamics and kinematics

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein-Cooper, Elijah Z.; Pardy, Stephen A. [Department of Astronomy, University of Wisconsin, 475 N Charter Street, Madison, WI 53706 (United States); Cannon, John M., E-mail: ezbc@astro.wisc.edu, E-mail: spardy@astro.wisc.edu, E-mail: jcannon@macalester.edu [Department of Physics and Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105 (United States); and others

    2014-08-01

    We present new H I spectral line imaging of the extremely metal-poor, star-forming dwarf irregular galaxy Leo P. Our H I images probe the global neutral gas properties and the local conditions of the interstellar medium (ISM). The H I morphology is slightly elongated along the optical major axis. We do not find obvious signatures of interaction or infalling gas at large spatial scales. The neutral gas disk shows obvious rotation, although the velocity dispersion is comparable to the rotation velocity. The rotation amplitude is estimated to be V {sub c} =15 ± 5 km s{sup –1}. Within the H I radius probed by these observations, the mass ratio of gas to stars is roughly 2:1, while the ratio of the total mass to the baryonic mass is ≳15:1. We use this information to place Leo P on the baryonic Tully-Fisher relation, testing the baryonic content of cosmic structures in a sparsely populated portion of parameter space that has hitherto been occupied primarily by dwarf spheroidal galaxies. We detect the signature of two temperature components in the neutral ISM of Leo P; the cold and warm components have characteristic velocity widths of 4.2 ± 0.9 km s{sup –1} and 10.1 ± 1.2 km s{sup –1}, corresponding to kinetic temperature upper limits of ∼1100 K and ∼6200 K, respectively. The cold H I component is unresolved at a physical resolution of 200 pc. The highest H I surface densities are observed in close physical proximity to the single H II region. A comparison of the neutral gas properties of Leo P with other extremely metal-deficient (XMD) galaxies reveals that Leo P has the lowest neutral gas mass of any known XMD, and that the dynamical mass of Leo P is more than two orders of magnitude smaller than any known XMD with comparable metallicity.

  18. ALFALFA DISCOVERY OF THE NEARBY GAS-RICH DWARF GALAXY LEO P. I. H I OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Giovanelli, Riccardo; Haynes, Martha P.; Adams, Elizabeth A. K. [Center for Radiophysics and Space Research, Space Sciences Building, Cornell University, Ithaca, NY 14853 (United States); Cannon, John M.; Bernstein-Cooper, Elijah Z. [Department of Physics and Astronomy, Macalester College, Saint Paul, MN 55105 (United States); Rhode, Katherine L.; Salzer, John J. [Department of Astronomy, Indiana University, Bloomington, IN 47405 (United States); Skillman, Evan D.; McQuinn, Kristen B. W., E-mail: riccardo@astro.cornell.edu, E-mail: haynes@astro.cornell.edu, E-mail: betsey@astro.cornell.edu, E-mail: jcannon@macalester.edu, E-mail: ebernste@macalester.edu, E-mail: rhode@astro.indiana.edu, E-mail: slaz@astro.indiana.edu, E-mail: skillman@astro.umn.edu, E-mail: kmcquinn@astro.umn.edu [Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455 (United States)

    2013-07-01

    The discovery of a previously unknown 21 cm H I line source identified as an ultra-compact high velocity cloud in the ALFALFA survey is reported. The H I detection is barely resolved by the Arecibo 305 m telescope {approx}4' beam and has a narrow H I linewidth (half-power full width of 24 km s{sup -1}). Further H I observations at Arecibo and with the Very Large Array corroborate the ALFALFA H I detection, provide an estimate of the H I radius, {approx}1' at the 5 Multiplication-Sign 10{sup 19} cm{sup -2} isophote, and show the cloud to exhibit a velocity field which, if interpreted as disk rotation, has an amplitude of {approx_equal}9.0 {+-} 1.5 km s{sup -1}. In other papers, Rhode et al. show the H I source to have a resolved stellar counterpart and ongoing star forming activity, while Skillman et al. reveal it as having extremely low metallicity: 12 + log (O/H) = 7.16 {+-} 0.04. The H I mass to stellar mass ratio of the object is found to be 2.6. We use the Tully-Fisher template relation in its baryonic form to obtain a distance estimate D{sub Mpc}=1.3{sup +0.9}{sub -0.5}. Additional constraints on the distance are also provided by the optical data of Rhode et al. and McQuinn et al., both indicating a distance in the range of 1.5 to 2.0 Mpc. The three estimates are compatible within their errors. The object appears to be located beyond the dynamical boundaries of, but still in close proximity to the Local Group. Its pristine properties are consistent with the sedate environment of its location. At a nominal distance of 1.75 Mpc, it would have an H I mass of {approx_equal} 1.0 Multiplication-Sign 10{sup 6} M {sub Sun }, a stellar mass of {approx_equal} 3.6 Multiplication-Sign 10{sup 5} M {sub Sun }, and a dynamical mass within the H I radius of {approx_equal} 1.5 Multiplication-Sign 10{sup 7} M {sub Sun }. This discovery supports the idea that optically faint-or altogether dark-low mass halos may be detectable through their non-stellar baryons.

  19. ALFALFA DISCOVERY OF THE NEARBY GAS-RICH DWARF GALAXY LEO P. I. H I OBSERVATIONS

    International Nuclear Information System (INIS)

    The discovery of a previously unknown 21 cm H I line source identified as an ultra-compact high velocity cloud in the ALFALFA survey is reported. The H I detection is barely resolved by the Arecibo 305 m telescope ∼4' beam and has a narrow H I linewidth (half-power full width of 24 km s–1). Further H I observations at Arecibo and with the Very Large Array corroborate the ALFALFA H I detection, provide an estimate of the H I radius, ∼1' at the 5 × 1019 cm–2 isophote, and show the cloud to exhibit a velocity field which, if interpreted as disk rotation, has an amplitude of ≅9.0 ± 1.5 km s–1. In other papers, Rhode et al. show the H I source to have a resolved stellar counterpart and ongoing star forming activity, while Skillman et al. reveal it as having extremely low metallicity: 12 + log (O/H) = 7.16 ± 0.04. The H I mass to stellar mass ratio of the object is found to be 2.6. We use the Tully-Fisher template relation in its baryonic form to obtain a distance estimate DMpc=1.3+0.9-0.5. Additional constraints on the distance are also provided by the optical data of Rhode et al. and McQuinn et al., both indicating a distance in the range of 1.5 to 2.0 Mpc. The three estimates are compatible within their errors. The object appears to be located beyond the dynamical boundaries of, but still in close proximity to the Local Group. Its pristine properties are consistent with the sedate environment of its location. At a nominal distance of 1.75 Mpc, it would have an H I mass of ≅ 1.0 × 106 M ☉, a stellar mass of ≅ 3.6 × 105 M ☉, and a dynamical mass within the H I radius of ≅ 1.5 × 107 M ☉. This discovery supports the idea that optically faint—or altogether dark—low mass halos may be detectable through their non-stellar baryons.

  20. Comparison of the VIMOS-VLT Deep Survey with the Munich semi-analytical model. II. The colour-density relation up to z=1.5

    CERN Document Server

    Cucciati, O; Zucca, E; Iovino, A; de la Torre, S; Pozzetti, L; Blaizot, J; Zamorani, G; Bolzonella, M; Vergani, D; Bardelli, S; Tresse, L; Pollo, A

    2012-01-01

    [Abridged] We perform on galaxy mock catalogues the same colour-density (C-D) analysis made by Cucciati et al. (2006) on a 5 Mpc/h scale using the VVDS-Deep survey, and compare the results from mocks with observed data. We use mock catalogues with the same flux limits (I=24) as the VVDS (CMOCKS), built using the semi-analytic model by De Lucia & Blaizot (2007) applied to the Millennium Simulation. From CMOCKS, we extracted samples of galaxies mimicking the VVDS observational strategy (OMOCKS). We computed the B-band Luminosity Function LF and the C-D relation in the mocks. We find that the LF in mocks roughly agrees with the observed LF, but at z1.5, and/or that galaxy colour is affected by environment on scales <5 Mpc/h, and this is not mirrored on larger scales. The reversal of the C-D relation can be explained by wet mergers between young galaxies, producing a starburst event. This should be seen on group scales. A residual of this is found in observations at z=1.5 on larger scales (5 Mpc/h), but no...

  1. VIIRS F1 "best" relative spectral response characterization by the government team

    Science.gov (United States)

    Moeller, Chris; McIntire, Jeff; Schwarting, Tom; Moyer, Dave

    2011-10-01

    The VIIRS Flight 1 (F1) instrument completed sensor level testing, including relative spectral response (RSR) characterization in 2009 and is moving forward towards a launch on the NPP platform late in 2011. As part of its mandate to produce analyses of F1 performance essentials, the VIIRS Government Team, consisting of NASA, Aerospace Corp., and MIT/Lincoln Lab elements, has produced an independent (from that of industry) analysis of F1 RSR. The test data used to derive RSR for all VIIRS spectral bands was collected in the TVAC environment using the Spectral Measurement Assembly (SpMA), a dual monochromator system with tungsten and ceramic glow bar sources. These spectrally contiguous measurements were analyzed by the Government Team to produce a complete in-band + out-of-band RSR for 21 of the 22 VIIRS bands (exception of the Day-Night Band). The analysis shows that VIIRS RSR was well measured in the pre-launch test program for all bands, although the measurement noise floor is high on the thermal imager band I5. The RSR contain expected detector to detector variation resulting from the VIIRS non-telecentric optical design, and out-of-band features are present in some bands; non-compliances on the integrated out-of-band spectral performance metric are noted in M15 and M16A,B bands and also for several VisNIR bands, though the VisNIR non-compliances were expected due to known scattering in the VisNIR integrated filter assembly. The Government Team "best" RSR have been released into the public domain for use by the science community in preparation for the post-launch era of VIIRS F1.

  2. A Relational Concept of Machian Relativity

    CERN Document Server

    Telkamp, Herman

    2012-01-01

    Mach's principle fits into the wider "relational principle", advocating that not only inertia, but also space and time emerge from the interaction of matter. Concepts of a Machian/relational theory are proposed, where inertia and energy are defined as mutual properties between pairs of objects. Due to Berkeley, only radial motion represents kinetic energy between (point) masses, which is the basis of anisotropic inertia, which in turn underlies the relational principle. The Newtonian definition of potential energy is considered a model for Machian inertia, leading to a frame independent definition of Machian kinetic energy, which comprises of the Newtonian terms (relative to the "fixed stars") and small anisotropic Machian energy terms between objects. The latter account for relativistic trajectories, such as the anomalous perihelion precession and Lense-Thirring frame dragging. However, relativistic effects of remote observation (e.g. time dilation) demand an isotropic model. A relational spacetime metric is...

  3. Tests Related to Pregnancy

    Science.gov (United States)

    ... to learn. Search form Search Tests related to pregnancy You are here Home Testing & Services Testing for ... to Genetic Counseling . What Are Tests Related to Pregnancy? Pregnancy related testing is done before or during ...

  4. Fetal Risks, Relative Risks, and Relatives' Risks.

    Science.gov (United States)

    Minkoff, Howard; Marshall, Mary Faith

    2016-01-01

    Several factors related to fetal risk render it more or less acceptable in justifying constraints on the behavior of pregnant women. Risk is an unavoidable part of pregnancy and childbirth, one that women must balance against other vital personal and family interests. Two particular issues relate to the fairness of claims that pregnant women are never entitled to put their fetuses at risk: relative risks and relatives' risks. The former have been used-often spuriously-to advance arguments against activities, such as home birth, that may incur risk; the latter implicate the nature of relationships in determining the acceptability of coercing or precluding activities. Motivated reasoning by clinicians and judges leads to inaccurate risk assessments, and judgments based on false claims to objectivity. Such judgments undermine the moral and legal standing of pregnant women and do not advance the interests of fetuses, pregnant women, families, or states. PMID:26832079

  5. Relative entropy equals bulk relative entropy

    CERN Document Server

    Jafferis, Daniel L; Maldacena, Juan; Suh, S Josephine

    2015-01-01

    We consider the gravity dual of the modular Hamiltonian associated to a general subregion of a boundary theory. We use it to argue that the relative entropy of nearby states is given by the relative entropy in the bulk, to leading order in the bulk gravitational coupling. We also argue that the boundary modular flow is dual to the bulk modular flow in the entanglement wedge, with implications for entanglement wedge reconstruction.

  6. Relational Lattice Axioms

    CERN Document Server

    Spight, Marshall

    2008-01-01

    Relational lattice is a formal mathematical model for Relational algebra. It reduces the set of six classic relational algebra operators to two: natural join and inner union. We continue to investigate Relational lattice properties with emphasis onto axiomatic definition. New results include additional axioms, equational definition for set difference (more generally anti-join), and case study demonstrating application of the relational lattice theory for query transformations.

  7. Evaluation of Public Relations

    OpenAIRE

    Vrabcová, Sabina

    2013-01-01

    This thesis is focused on public relations (public relations), as an integral part of running any successful company. The thesis is divided into two parts. The theoretical part describes the main objectives and tools of public relations. It represents the concept of public relations as part of the communication mix and defines it. The practical part of the thesis is focused on the importance of public relations in a selected company moving in the photography industry. This section evalu...

  8. Introduction to the anisotropic geometrodynamics

    CERN Document Server

    Siparov, Sergey

    2012-01-01

    The aim of the book is to provide a new and fruitful approach to the challenging problems of modern physics, astrophysics, and cosmology. The well-known observations of the flat rotation curves of spiral galaxies and of the gravitational lensing effect greatly exceeding the expectations based on the classical GRT can be explained without bringing in the notion of dark matter. The Tully-Fisher law and the unusual features of globular clusters' motion become clear. It also turns out that new features appear in the cosmological picture that involves the Universe expansion and the acceleration of

  9. DARK MATTER AND DARK ENERGY OF THE UNIVERSE INRIA-SACLAYS Version

    OpenAIRE

    Delort, Thierry

    2016-01-01

    In this article, we propose a new model of dark matter. According to this new model, dark matter is a substance, that is a new physical element not constituted of classical particles, called dark substance and filling the Universe. Assuming some very simple physical properties to this dark substance, we theoretically justify the flat rotation curve of galaxies and the baryonic Tully-Fisher's law. Then using the new model of dark matter we are naturally led to propose a new geometrical model o...

  10. The LCO/Palomar 10,000 km/sec Cluster Survey. II. Constraints on Large-Scale Streaming

    OpenAIRE

    Willick, Jeffrey A.

    1998-01-01

    The LCO/Palomar 10,000 km/sec (LP10K) Tully-Fisher (TF) data set is used to test for bulk streaming motions on a ~150 Mpc scale. The sample consists of 172 cluster galaxies in the original target range of the survey, 9000-13,000 km/sec, plus an additional 72 galaxies with cz < 30,000 km/sec. A maximum-likelihood analysis that is insensitive to Malmquist and selection bias effects is used to constrain the bulk velocity parameters, and realistic Monte-Carlo simulations are carried out to correc...

  11. Measuring Relative Humidity.

    Science.gov (United States)

    Pinkham, Chester A.; Barrett, Kristin Burrows

    1992-01-01

    Describes four experiments that enable students to explore the phenomena of evaporation and condensation and determine the relative humidity by measuring air temperature and dew point on warm September days. Provides tables to calculate saturation points and relative humidity. (MDH)

  12. Category Theory in Relativity

    CERN Document Server

    Wagh, Sanjay M

    2007-01-01

    Measures in the context of Category Theory lead to various relations, even differential relations, of categories that are independent of the mathematical structure forming objects of a category. Such relations, which are independent of the mathematical structure that we may represent a physical body or a system of reference with, are, precisely, demanded to be the Laws of Physics by the General Principle of Relativity.

  13. Evaluation of Public Relations

    OpenAIRE

    Poštová, Martina

    2012-01-01

    The aim of bachelor thesis is the evaluation of Public Relations for Nestlé. A partial order is, based on the gathered informatik from literature, describing the importance of Public Relations campaigns in the communication society. Specifically, the most used instruments, the main objectives, structure, models of public relations and its importace in crisis situations. The Company can use to influence with Public Relations the general public, journalists etc. in positiv...

  14. Relativity without tears

    OpenAIRE

    Z. K. Silagadze

    2007-01-01

    Special relativity is no longer a new revolutionary theory but a firmly established cornerstone of modern physics. The teaching of special relativity, however, still follows its presentation as it unfolded historically, trying to convince the audience of this teaching that Newtonian physics is natural but incorrect and special relativity is its paradoxical but correct amendment. I argue in this article in favor of logical instead of historical trend in teaching of relativity and that special ...

  15. Relational Mathematics Continued

    OpenAIRE

    Schmidt, Gunther; Winter, Michael

    2014-01-01

    This is in some sense an addendum to the book Relational Mathematics by the first-named author. It originated from work on diverse other topics during which a lot of purely relational results with broad applicability have been produced. These include results on domain construction with novel formulae for existential and inverse image, a relational calculus for binary mappings, and the development of a formally derived relational calculus of Kronecker-, strict fork-, and strict join-operators....

  16. Enhanced Information Exclusion Relations

    OpenAIRE

    Xiao, Yunlong; Jing, Naihuan; Li-Jost, Xianqing

    2016-01-01

    In Hall's reformulation of the uncertainty principle, the entropic uncertainty relation occupies a core position and provides the first nontrivial bound for the information exclusion principle. Based upon recent developments on the uncertainty relation, we present new bounds for the information exclusion relation using majorization theory and combinatoric techniques, which reveal further characteristic properties of the overlap matrix between the measurements.

  17. The Fundamental Property Relation.

    Science.gov (United States)

    Martin, Joseph J.

    1983-01-01

    Discusses a basic equation in thermodynamics (the fundamental property relation), focusing on a logical approach to the development of the relation where effects other than thermal, compression, and exchange of matter with the surroundings are considered. Also demonstrates erroneous treatments of the relation in three well-known textbooks. (JN)

  18. Decreasing Relative Risk Premium

    DEFF Research Database (Denmark)

    Hansen, Frank

    We consider the risk premium demanded by a decision maker with wealth x in order to be indifferent between obtaining a new level of wealth y1 with certainty, or to participate in a lottery which either results in unchanged present wealth or a level of wealth y2 > y1. We define the relative risk...... premium as the quotient between the risk premium and the increase in wealth y1–x which the decision maker puts on the line by choosing the lottery in place of receiving y1 with certainty. We study preferences such that the relative risk premium is a decreasing function of present wealth, and we determine....... Decreasing relative risk premium in the small implies decreasing relative risk premium in the large, and decreasing relative risk premium everywhere implies risk aversion. We finally show that preferences with decreasing relative risk premium may be equivalently expressed in terms of certain preferences on...

  19. Enhanced Information Exclusion Relations

    Science.gov (United States)

    Xiao, Yunlong; Jing, Naihuan; Li-Jost, Xianqing

    2016-01-01

    In Hall’s reformulation of the uncertainty principle, the entropic uncertainty relation occupies a core position and provides the first nontrivial bound for the information exclusion principle. Based upon recent developments on the uncertainty relation, we present new bounds for the information exclusion relation using majorization theory and combinatoric techniques, which reveal further characteristic properties of the overlap matrix between the measurements. PMID:27460975

  20. Towards Applicative Relational Programming

    OpenAIRE

    Ibrahim, H.; van Emden, M. H.

    2006-01-01

    Functional programming comes in two flavours: one where ``functions are first-class citizens'' (we call this applicative) and one which is based on equations (we call this declarative). In relational programming clauses play the role of equations. Hence Prolog is declarative. The purpose of this paper is to provide in relational programming a mathematical basis for the relational analog of applicative functional programming. We use the cylindric semantics of first-order logic due to Tarski an...

  1. Relative fixed point theory

    OpenAIRE

    Ponto, Kate

    2009-01-01

    The Lefschetz fixed point theorem and its converse have many generalizations. One of these generalizations is to endomorphisms of a space relative to a fixed subspace. In this paper we define relative Lefschetz numbers and Reidemeister traces using traces in bicategories with shadows. We use the functoriality of this trace to identify different forms of these invariants and to prove a relative Lefschetz fixed point theorem and its converse.

  2. Decreasing relative risk premium

    DEFF Research Database (Denmark)

    Hansen, Frank

    2007-01-01

    such that the corresponding relative risk premium is a decreasing function of present wealth, and we determine the set of associated utility functions. We find a new characterization of risk vulnerability and determine a large set of utility functions, closed under summation and composition, which are...... both risk vulnerable and have decreasing relative risk premium. We finally introduce the notion of partial risk neutral preferences on binary lotteries and show that partial risk neutrality is equivalent to preferences with decreasing relative risk premium...

  3. Modernization of credit relations.

    OpenAIRE

    S.V. Volosovich

    2015-01-01

    Nowadays it is essential to modernize credit relations in the conditions of global economy transformations. This is due to the influence of integration processes on credit relations and transformation of the risks inherent in the credit field. The purpose of this article is to develop measures that help to improve the efficiency of interaction of credit relations’ participants. Modernization of credit relations is based on the interaction of its main and indirect subjects who belong to t...

  4. Introduction to relational programming

    OpenAIRE

    MacLennan, Bruce J.

    2013-01-01

    A new method of programming, called relational programming, is introduced. This is a style of programming in which entire relations are manipulated rather than individual data. This is analogous to functional programming, wherein entire functions are the value manipulated by the operators. Because of its ability to manipulate complex data structures other than lists, relational programming seems to have distinct advantages over other very high level languages. This paper introduces the basic ...

  5. Relative Thinking Theory

    OpenAIRE

    Azar, Ofer H.

    2005-01-01

    The article presents a theory that I denote “Relative Thinking Theory,” which claims that people consider relative differences and not only absolute differences when making various economics decisions, even in those cases where the rational model dictates that people should consider only absolute differences. The article reviews experimental evidence for this behavior, summarizing briefly several experiments I conducted, as well as some earlier related literature. It then discusses how we can...

  6. Gaining Relational Competitive Advantages

    DEFF Research Database (Denmark)

    Hu, Yimei; Zhang, Si; Li, Jizhen;

    2015-01-01

    Establishing strategic technological partnerships (STPs) with foreign partners is an increasingly studied topic within the innovation management literature. Partnering firms can jointly create sources of relational competitive advantage. Chinese firms often lack research and development (R......&D) capabilities but are increasingly becoming preferred technological partners for transnational corporations. We investigate an STP between a Scandinavian and a Chinese firm and try to explore how to gain relational competitive advantage by focusing on its two essential stages: relational rent generation and...... appropriation. Based on an explorative case study, we develop a conceptual framework that consists of process, organizational alliance factors, and coordination modes that we propose lead to relational competitive advantage....

  7. Petroleum related hazards relating to Desert Storm

    International Nuclear Information System (INIS)

    In this paper the findings and recommendations of a workshop convened to discuss the toxicity of crude oil and associated chemicals as related to military operations during Operation Desert Storm are presented. Since concern was limited to military operations, only acute toxicity, combustion hazard and explosive hazard were considered. These recommendations were developed to assist operational and medical personnel serving in the Middle East, but have some relevancy to operations that continue during the process of mitigating the damage done to that region. The issues arising from the large amount of oil fire smoke currently being produced by burning Kuwaiti wells were not addressed by the workshop. However, workshop findings indicate a need to study the composition, distribution and health consequences of oil smoke exposure

  8. Reciprocal relations in electroacoustics

    International Nuclear Information System (INIS)

    In a colloidal suspension, one can generate sound waves by the application of an alternating electric field (Electrokinetic Sonic Amplitude, i.e., ESA). Another phenomenon is electrophoresis (Electrophoretic Mobility, i.e., EM) where a colloidal particle moves relative to the solvent in an electric field. Vice versa one can generate electric fields or electric currents by sound waves (Colloid Vibration Potential/Current, i.e., CVP/CVI). In 1988 and 1990, O’Brien [J. Fluid Mech. 190, 71–86 (1988) and O’Brien, J. Fluid Mech. 212, 81–93 (1990)] derived a reciprocal relation between the proportionality coefficients of the EM and CVI phenomena. In this paper, we will generalize his proof by constructing the relevant entropy production from which the linear force-flux relations follow. General relations are derived for electrolyte solutions, of which colloidal suspensions are a particular case. The relations between CVI, CVP, EM, and ESA are discussed. O’Brien's reciprocal relation then follows as an Onsager relation. The relation is valid for any applied electric field frequency, particle surface charge and particle concentration (even in the presence of particle-particle interactions) provided the system is isotropic

  9. Relative Effects at Work

    NARCIS (Netherlands)

    Braeken, Johan; Mulder, Joris; Wood, Stephen

    2015-01-01

    Assessing the relative importance of predictors has been of historical importance in a variety of disciplines including management, medicine, economics, and psychology. When approaching hypotheses on the relative ordering of the magnitude of predicted effects (e.g., the effects of discrimination

  10. Relational Processing Following Stroke

    Science.gov (United States)

    Andrews, Glenda; Halford, Graeme S.; Shum, David; Maujean, Annick; Chappell, Mark; Birney, Damian

    2013-01-01

    The research examined relational processing following stroke. Stroke patients (14 with frontal, 30 with non-frontal lesions) and 41 matched controls completed four relational processing tasks: sentence comprehension, Latin square matrix completion, modified Dimensional Change Card Sorting, and n-back. Each task included items at two or three…

  11. Forces in General Relativity

    Science.gov (United States)

    Ridgely, Charles T.

    2010-01-01

    Many textbooks dealing with general relativity do not demonstrate the derivation of forces in enough detail. The analyses presented herein demonstrate straightforward methods for computing forces by way of general relativity. Covariant divergence of the stress-energy-momentum tensor is used to derive a general expression of the force experienced…

  12. Teaching Mediated Public Relations.

    Science.gov (United States)

    Kent, Michael L.

    2001-01-01

    Discusses approaches to teaching a mediated public relations course, emphasizing the World Wide Web. Outlines five course objectives, assignments and activities, evaluation, texts, and lecture topics. Argues that students mastering these course objectives will understand ethical issues relating to media use, using mediated technology in public…

  13. Measuring Relational Reasoning

    Science.gov (United States)

    Alexander, Patricia A.; Dumas, Denis; Grossnickle, Emily M.; List, Alexandra; Firetto, Carla M.

    2016-01-01

    Relational reasoning is the foundational cognitive ability to discern meaningful patterns within an informational stream, but its reliable and valid measurement remains problematic. In this investigation, the measurement of relational reasoning unfolded in three stages. Stage 1 entailed the establishment of a research-based conceptualization of…

  14. The Redshifts in Relativity

    Science.gov (United States)

    Singh, Satya Pal; Singh, Apoorva; Hareet, Prabhav

    2011-01-01

    The progress of modern cosmology took off in 1917 when A. Einstein published his paper on general theory of relativity extending his work of special theory of relativity (1905). In 1922 Alexander Friedmann constructed a mathematical model for expanding Universe that had a big bang in remote past. The experimental evidences could come in 1929 by…

  15. Relational Perspectives on Leading

    DEFF Research Database (Denmark)

    Relational Perspectives on Leading discusses leadership from a relational and social constructionism perspective as practiced on an everyday basis between people. The book pursues a fast growing, practice-based approach - particularly within the Anglo-Saxon parts of the world - to organization...

  16. Heat-Related Illnesses

    Medline Plus

    Full Text Available ... So Long? Admission to the Hospital Heroes on Medicine's Front Line Observation Emergency Care Fact Sheet ... Heat-Related Illnesses Dr. Glenn Mitchell , Emergency physician at Mercy Health System in Chesterfield, Missouri Heat-related illness can be ...

  17. Spinors, Relativity and Nonlocality

    CERN Document Server

    Dvoeglazov, V V

    2001-01-01

    The Ryder relation between left- and right- spinors has been generalized in my previous works. On this basis Ahluwalia presented a physical content following from this generalization. It is related to non-locality. A similar conclusion can be drawn on the basis of a generalization of the Sakurai-Gersten consideration. I correct several calculating and conceptual misunderstandings of the previous works.

  18. Asbestos Related Disorders

    OpenAIRE

    Raymond Bégin; André Dufresne; François Plante; Serge Massé

    1994-01-01

    An updated summary of current understanding of asbestos related disorders is presented, along with a review of the history of the disorders, and the mineralogy, biological tissue burden, pathogenesis, pathology and clinical aspects of the asbestos related disorders, with particular emphasis on important information for the clinician.

  19. Relative Lyapunov Center Bifurcations

    DEFF Research Database (Denmark)

    Wulff, Claudia; Schilder, Frank

    2014-01-01

    Relative equilibria (REs) and relative periodic orbits (RPOs) are ubiquitous in symmetric Hamiltonian systems and occur, for example, in celestial mechanics, molecular dynamics, and rigid body motion. REs are equilibria, and RPOs are periodic orbits of the symmetry reduced system. Relative Lyapunov...... center bifurcations are bifurcations of RPOs from REs corresponding to Lyapunov center bifurcations of the symmetry reduced dynamics. In this paper we first prove a relative Lyapunov center theorem by combining recent results on the persistence of RPOs in Hamiltonian systems with a symmetric Lyapunov...... center theorem of Montaldi, Roberts, and Stewart. We then develop numerical methods for the detection of relative Lyapunov center bifurcations along branches of RPOs and for their computation. We apply our methods to Lagrangian REs of the N-body problem....

  20. General relativity and cosmology

    CERN Document Server

    Bucher, Martin

    2015-01-01

    This year marks the hundredth anniversary of Einstein's 1915 landmark paper "Die Feldgleichungen der Gravitation" in which the field equations of general relativity were correctly formulated for the first time, thus rendering general relativity a complete theory. Over the subsequent hundred years physicists and astronomers have struggled with uncovering the consequences and applications of these equations. This contribution, which was written as an introduction to six chapters dealing with the connection between general relativity and cosmology that will appear in the two-volume book "One Hundred Years of General Relativity: From Genesis and Empirical Foundations to Gravitational Waves, Cosmology and Quantum Gravity," endeavors to provide a historical overview of the connection between general relativity and cosmology, two areas whose development has been closely intertwined.

  1. General relativity and cosmology

    Science.gov (United States)

    Bucher, Martin; Ni, Wei-Tou

    2015-10-01

    This year marks the 100th anniversary of Einstein’s 1915 landmark paper “Die Feldgleichungen der Gravitation” in which the field equations of general relativity were correctly formulated for the first time, thus rendering general relativity a complete theory. Over the subsequent hundred years, physicists and astronomers have struggled with uncovering the consequences and applications of these equations. This paper, which was written as an introduction to six chapters dealing with the connection between general relativity and cosmology that will appear in the two-volume book One Hundred Years of General Relativity: From Genesis and Empirical Foundations to Gravitational Waves, Cosmology and Quantum Gravity, endeavors to provide a historical overview of the connection between general relativity and cosmology, two areas whose development has been closely intertwined.

  2. Relativity without tears

    CERN Document Server

    Silagadze, Z K

    2007-01-01

    Special relativity is no more a new revolutionary theory but firmly established cornerstone of modern physics. The teaching of special relativity, however, still follows its presentation as it was unfolded historically, trying to convince subjects of this teaching that Newtonian physics is natural but incorrect and special relativity is its paradoxical but correct amendment. I argue in this article in favor of logical instead of historical trend in teaching of relativity and that special relativity is neither paradoxical nor correct (in the absolute sense of nineteen century) but the most natural expected description of real space-time around us valid for all practical purposes. This last circumstance constitutes a profound mystery of modern physics better known as the cosmological constant problem.

  3. Modernization of credit relations

    Directory of Open Access Journals (Sweden)

    S.V. Volosovich

    2015-03-01

    Full Text Available Nowadays it is essential to modernize credit relations in the conditions of global economy transformations. This is due to the influence of integration processes on credit relations and transformation of the risks inherent in the credit field. The purpose of this article is to develop measures that help to improve the efficiency of interaction of credit relations’ participants. Modernization of credit relations is based on the interaction of its main and indirect subjects who belong to the subsystems of loans granting, deposits attraction and provision of related services. Its goal is to pass from extensive to intensive model of interaction between the subjects of credit relations. Components of the credit relations modernization are the following: institutional modernization, which is based on the interaction of credit relations’ subjects, and ensures the development of competition in all credit market’s segments, the creation of its corresponding infrastructure, qualitative change in the approaches of regulation and supervision; technological modernization, which involves the formation of joint products on the credit market and the formation of an integrated informational and analytical system. In the result of the credit relations’ modernization it is expected to achieve synergies between the subjects of credit relations, that will lead to changes in the business architecture of the financial market.

  4. Ether formulations of relativity

    Energy Technology Data Exchange (ETDEWEB)

    Duffy, M.C.

    1980-12-01

    Contemporary ether theories are surveyed and criticized, especially those formally identical to orthodox Relativity. The historical development of Relativity, Special and General, in terms of an ether, is briefly indicated. Classical interpretations of Generalized Relativity using ether are compared to Euclidean formulations using a background space. The history of a sub-group of theories, formulating a 'new' Relativity involving modified transforms, is outlined. According to the theory with which they agree, recent supposed detections of drift are classified and criticized. Cosmological evidence suggesting an ether is mentioned. Only ether theories formally identical to Relativity have been published in depth. They stand criticized as being contrary to the positivist spirit. The history of mechanical analogues is traced, from Hartley's representing gravitating matter as spherical standing waves, to recent suggestions that vortex-sponge might model electromagnetic, quantum, uncertainty and faster-than-light phenomena. Contemporary theories are particular physical theories, themselves 'second interpretations' of a primary mathematical model. Mechanical analogues are auxiliary, not necessary, to other theory, disclosing relationships between classical and non-classical descriptions of assemblies charging state. The ether-relativity polemic, part of a broader dispute about relativity, is founded on mistaken conceptions of the roles of mathematical and physical models, mechanical analogues; and a distored view of history, which indicates that ether theories have become relativistic. 103 references.

  5. Ether formulations of relativity

    International Nuclear Information System (INIS)

    Contemporary ether theories are surveyed and criticised, especially those formally identical to orthodox Relativity. The historical development of Relativity, Special and General, in terms of an ether, is briefly indicated. Classical interpretations of Generalized Relativity using ether are compared to Euclidean formulations using a background space. The history of a sub-group of theories, formulating a 'new' Relativity involving modified transforms, is outlined. According to the theory with which they agree, recent supposed detections of drift are classified and criticised. Cosmological evidence suggesting an ether is mentioned. Only ether theories formally identical to Relativity have been published in depth. They stand criticised as being contrary to the positivist spirit. The history of mechanical analogues is traced, from Hartley's representing gravitating matter as spherical standing waves, to recent suggestions that vortex-sponge might model electromagnetic, quantum, uncertainty and faster-than-light phenomena. Contemporary theories are particular physical theories, themselves 'second interpretations' of a primary mathematical model. Mechanical analogues are auxiliary, not necessary, to other theory, disclosing relationships between classical and non-classical descriptions of assemblies charging state. The ether-relativity polemic, part of a broader dispute about relativity, is founded on mistaken conceptions of the roles of mathematical and physical models, mechanical analogues; and a distored view of history, which indicates that ether theories have become relativistic. (author)

  6. Human Relations-skolen

    DEFF Research Database (Denmark)

    Scheuer, Steen

    2014-01-01

    , men også arbejdssociologien, arbejdspsykologien og human resource development. Den første retning udsprang af de såkaldte Hawthorne-eksperimenter og psykologen Elton Mayos bearbejdelse af resultaterne derfra. Den anden er en løsere gruppering bestående af navne som Abraham Maslow og Frederick Herzberg...... der mellem Human Relations (Hawthorne-eksperimenter ne) og Neo-Human Relations (behovsteorierne), men i denne fremstilling bruges Human Relations som en samlebetegnelse for begge disse – noget forskellige – forskningstraditioner. De har i dag opnået stor udbredelse og er praktisk talt obligatorisk...

  7. Wavelets with Differential Relation

    Institute of Scientific and Technical Information of China (English)

    Zhi-Tao CHUANG; Youming LIU

    2011-01-01

    Divergence-free wavelets are successfully applied to numerical solutions of Navier-Stokes equation and to analysis of incompressible flows. They closely depend on a pair of one-dimensional wavelets with some differential relations. In this paper, we point out some restrictions of those wavelets and study scaling functions with the differential relation; Wavelets and their duals are discussed; In addition to the differential relation, we are particularly interested in a class of examples with the interpolatory property; It turns out there is a connection between our examples and Micchelli's work.

  8. Special theory of relativity

    CERN Document Server

    Kilmister, Clive William

    1970-01-01

    Special Theory of Relativity provides a discussion of the special theory of relativity. Special relativity is not, like other scientific theories, a statement about the matter that forms the physical world, but has the form of a condition that the explicit physical theories must satisfy. It is thus a form of description, playing to some extent the role of the grammar of physics, prescribing which combinations of theoretical statements are admissible as descriptions of the physical world. Thus, to describe it, one needs also to describe those specific theories and to say how much they are limit

  9. Ether and Relativity

    CERN Document Server

    Farhoudi, Mehrdad

    2015-01-01

    We consider one of the fundamental debates in performing the relativity theory, namely, the ether and the relativity points of view, in a way to aid the learning of the subjects. In addition, we present our views and prospects while describing the issues that being accessible to many physicists and allowing broader views. Also, we very briefly review the two almost recent observations of the Webb redshift and the ultra high-energy cosmic rays, and the modified relativity models that have been presented to justify them, wherein we express that these justifications have not been performed via a single model with a single mechanism.

  10. Public Relations vs. Propaganda

    Directory of Open Access Journals (Sweden)

    Alexandru BASTIAN

    2006-10-01

    Full Text Available The paper aims at presenting the characteristics, methods and aplications of two related activities – Public Relations and propaganda. Although different from the piont of wiev of purpose and results (the practice of Public Relations aims at establishing and maintaining mutual lines of communications, understanding, acceptance, and cooperation between an organization and its publics, through transparency and honesty, while propaganda insists on a message that is intended primarily to serve the interests of the messenger. in order to influence public opinion and to manipulate other people’s beliefs by any means necessary, the two activities also present quite a lot of similarities.

  11. Ether and Relativity

    Science.gov (United States)

    Farhoudi, Mehrdad; Yousefian, Maysam

    2016-05-01

    We consider one of the fundamental debates in performing the relativity theory, namely, the ether and the relativity points of view, in a way to aid the learning of the subjects. In addition, we present our views and prospects while describing the issues that being accessible to many physicists and allowing broader views. Also, we very briefly review the two almost recent observations of the Webb redshift and the ultra high energy cosmic rays, and the modified relativity models that have been presented to justify them, wherein we express that these justifications have not been performed via a single model with a single mechanism.

  12. Einstein's theory of relativity

    CERN Document Server

    Born, Max

    2012-01-01

    Semi-technical account includes a review of classical physics (origin of space and time measurements, Ptolemaic and Copernican astronomy, laws of motion, inertia, more) and of Einstein's theories of relativity.

  13. OPERA neutrinos and relativity

    CERN Document Server

    Amelino-Camelia, G; Kowalski-Glikman, J; Smolin, L

    2011-01-01

    In a recent study, Cohen and Glashow argue that superluminal neutrinos of the type recently reported by OPERA should be affected by anomalous Cherenkov-like processes. This causes them to loose much of their energy before reaching the OPERA detectors. Related concerns were reported also by Gonzalez-Mestres, who argued that pions cannot decay to superluminal neutrinos over part of the energy range studied by OPERA. We observe here that these arguments are set within a framework in which Lorentz symmetry is broken, by the presence of a preferred frame. We further show that these anomalous processes are forbidden if Lorentz symmetry is instead "deformed", preserving the relativity of inertial frames. These deformations add non-linear terms to energy momentum relations, conservation laws and Lorentz transformations in a way that is consistent with the relativity of inertial observers.

  14. Heat-Related Illnesses

    Medline Plus

    Full Text Available ... for Disasters Communication With Your Family And Your Doctor About Your Wishes Visiting the ER Who Takes ... 101 Heat-Related Illnesses Dr. Glenn Mitchell , Emergency physician at Mercy Health System in Chesterfield, Missouri Heat- ...

  15. Quantum Gauge General Relativity

    Institute of Scientific and Technical Information of China (English)

    WU Ning

    2004-01-01

    Based on gauge principle, a new model on quantum gravity is proposed in the frame work of quantum gauge theory of gravity. The model has local gravitational gauge symmetry, and the field equation of the gravitational gauge field is just the famous Einstein's field equation. Because of this reason, this model is called quantum gauge general relativity, which is the consistent unification of quantum theory and general relativity. The model proposed in this paper is a perturbatively renormalizable quantum gravity, which is one of the most important advantage of the quantum gauge general relativity proposed in this paper. Another important advantage of the quantum gauge general relativity is that it can explain both classical tests of gravity and quantum effects of gravitational interactions, such as gravitational phase effects found in COW experiments and gravitational shielding effects found in Podkletnov experiments.

  16. Heat-Related Illnesses

    Science.gov (United States)

    ... Emergencies A-Z Share this! Home » Emergency 101 Heat-Related Illnesses Dr. Glenn Mitchell , Emergency physician at ... about heat cramps and heat stroke and exhaustion. Heat Cramps Symptoms include muscle spasms, usually in the ...

  17. Heat-Related Illnesses

    Medline Plus

    Full Text Available ... Emergencies A-Z Share this! Home » Emergency 101 Heat-Related Illnesses Dr. Glenn Mitchell , Emergency physician at ... about heat cramps and heat stroke and exhaustion. Heat Cramps Symptoms include muscle spasms, usually in the ...

  18. Numerical Relativity and Astrophysics

    CERN Document Server

    Lehner, Luis

    2014-01-01

    Throughout the Universe many powerful events are driven by strong gravitational effects that require general relativity to fully describe them. These include compact binary mergers, black hole accretion and stellar collapse, where velocities can approach the speed of light, and extreme gravitational fields --$\\Phi_{\\rm Newt}/c^2 \\simeq 1$-- mediate the interactions. Many of these processes trigger emission across a broad range of the electromagnetic spectrum. Compact binaries further source strong gravitational wave emission that could directly be detected in the near future. This feat will open up a gravitational wave window into our Universe and revolutionize its understanding. Describing these phenomena requires general relativity, and --where dynamical effects strongly modify gravitational fields-- the full Einstein equations coupled to matter sources. Numerical relativity is a field within general relativity concerned with studying such scenarios that cannot be accurately modeled via perturbative or anal...

  19. CHLOROQUINE—RELATED DEPRESSION

    OpenAIRE

    Das, E. Mohan; Mohan, D.

    1981-01-01

    SUMMARY Drugs are known to induce depressive states. Chloroquine, an antimalarial, in therapeutic doses administered for malaria therapy, may produce symptoms rather indistinguishable from endogenous depression. The possible mechanisms of production of depression related to chloroquine use are hypothesised.

  20. ROE Sea Level Relative

    Data.gov (United States)

    U.S. Environmental Protection Agency — This point dataset represents changes in relative sea level along U.S. coasts, 1960-2013. Data were provided by the National Oceanic and Atmospheric Administration...

  1. General relativity and experiment

    OpenAIRE

    Damour, T.

    1994-01-01

    The confrontation between Einstein's theory of gravitation and experiment is summarized. Although all current experimental data are compatible with general relativity, the importance of pursuing the quest for possible deviations from Einstein's theory is emphasized.

  2. General relativity and mathematics

    International Nuclear Information System (INIS)

    General relativity is more than a theory of gravity, since any physical process occupies space and lasts for a time, forcing to reconcile that physical theory that describes what the dynamic nature of space-time itself. (Author)

  3. Publicity and public relations

    Science.gov (United States)

    Fosha, Charles E.

    1990-01-01

    This paper addresses approaches to using publicity and public relations to meet the goals of the NASA Space Grant College. Methods universities and colleges can use to publicize space activities are presented.

  4. Toward relational empowerment.

    Science.gov (United States)

    Christens, Brian D

    2012-09-01

    Psychological empowerment has been theorized as a construct with emotional, behavioral and cognitive components. Yet, many studies have stressed that empowerment processes are contingent on interpersonal relationships. Moreover, theory suggests that power is developed and exercised through relationships. This article makes the case that expanding our conceptions of psychological empowerment through the addition of a relational component can enhance our understanding of psychological empowerment and the effectiveness of empowerment-oriented community practice. Previous research on empowerment is reviewed for relational content, and additional insights into the relational context of empowerment processes are marshaled from other concepts in community research including social capital, sense of community, social networks, social support, and citizen participation. A new iteration of the nomological network for psychological empowerment is presented, including the elements of a relational component. PMID:22094588

  5. Cause Related Marketing

    OpenAIRE

    Hrabcová, Ivana

    2013-01-01

    This bachelor work is focused on the Cause Related Marketing (CRM) which may be a part of the marketing strategy of any particular company. This term mainly means cooperation between the private and non-profit sector created by using traditional marketing tools. These tools, e. g. advertising, public relations, licensing and marketing at large, are described at the beginning of the theoretical part. Furthermore this work focuses on Corporate Social Responsibility which is strongly connected t...

  6. Forecasting using relative entropy

    OpenAIRE

    Robertson, John C.; Ellis W. Tallman; Charles H. Whiteman

    2002-01-01

    The paper describes a relative entropy procedure for imposing moment restrictions on simulated forecast distributions from a variety of models. Starting from an empirical forecast distribution for some variables of interest, the technique generates a new empirical distribution that satisfies a set of moment restrictions. The new distribution is chosen to be as close as possible to the original in the sense of minimizing the associated Kullback-Leibler Information Criterion, or relative entrop...

  7. Managing or Relating?

    DEFF Research Database (Denmark)

    Sproedt, Henrik; Buur, Jacob

    2010-01-01

    This paper describes a case of user-driven innovation. We draw on social capital theory and the concept of complex responsive processes to examine the role of relations for the exchange and generation of knowledge across different knowledge traditions. We argue that innovation as a social...... phenomenon with a high degree of uncertainty and complexity requires more relating and less managing to use conflict as a resource by turning the friction between different knowledge traditions into creative friction....

  8. Research in Public Relations

    OpenAIRE

    Coriolan PĂUNESCU

    2006-01-01

    Research has an important role in public relations (PR) being necessary in developing strategies in this area. Therefore, we can speak of two types of research, the applied research and theoretical research, both being successfully used in the work of public relations. Applied research, can be strategic (used in programs in order to identify attitudes and opinions of the target public, to develop strategies for formulating and transmitting messages, to establish the criteria for evaluating th...

  9. Numerical Relativity Beyond Astrophysics

    OpenAIRE

    Garfinkle, David

    2016-01-01

    Though the main applications of computer simulations in relativity are to astrophysical systems such as black holes and neutron stars, nonetheless there are important applications of numerical methods to the investigation of general relativity as a fundamental theory of the nature of space and time. This paper gives an overview of some of these applications. In particular we cover (i) investigations of the properties of spacetime singularities such as those that occur in the interior of black...

  10. Special relativity (in Russian)

    OpenAIRE

    Grozin, Andrey

    2011-01-01

    A modern elementary introduction to special relativity for advanced school children or first-year university students, in Russian. I try to demonstrate that relativity does not contradict common sense; on the contrary, it follows from common sense logically. I discuss Minkowski space-time geometry in some detail. Geometrical approach, with few simple formulas but many pictures, makes results of the theory intuitively obvious.

  11. Looking beyond special relativity

    OpenAIRE

    Sidharth, B. G.

    2006-01-01

    Einstein's Special Theory of Relativity was proposed a little over a hundred years back. It remained a bedrock of twentieth century physics right up to Quantum Field Theory. However, the failure over several decades to provide a unified description of Electromagnetism and Gravitation or alternatively, Quantum Theory and General Relativity has finally lead researchers to abandon the differentiable spacetime manifold on which all of the above was based. In the most recent approaches we consider...

  12. Optimization of relative arbitrage

    OpenAIRE

    Ting-Kam Leonard Wong

    2014-01-01

    In stochastic portfolio theory, a relative arbitrage is an equity portfolio which is guaranteed to outperform a benchmark portfolio over a finite horizon. When the market is diverse and sufficiently volatile, and the benchmark is the market or a buy-and-hold portfolio, functionally generated portfolios introduced by Fernholz provide a systematic way of constructing relative arbitrages. In this paper we show that if the market portfolio is replaced by the equal or entropy weighted portfolio am...

  13. Querying Relational Concept Lattices

    OpenAIRE

    Azmeh, Zeina; Huchard, Marianne; Napoli, Amedeo; Rouane Hacene, Amine Mohamed; Valtchev, Petko

    2011-01-01

    Relational Concept Analysis (RCA) constructs conceptual abstractions from objects described by both own properties and inter-object links, while dealing with several sorts of objects. RCA produces lattices for each category of objects and those lattices are connected via relational attributes that are abstractions of the initial links. Navigating such interrelated lattice family in order to find concepts of interest is not a trivial task due to the potentially large size of the lattices and t...

  14. General Relativity Today

    OpenAIRE

    Damour, Thibault

    2007-01-01

    After recalling the conceptual foundations and the basic structure of general relativity, we review some of its main modern developments (apart from cosmology) : (i) the post-Newtonian limit and weak-field tests in the solar system, (ii) strong gravitational fields and black holes, (iii) strong-field and radiative tests in binary pulsar observations, (iv) gravitational waves, (v) general relativity and quantum theory.

  15. The theories of relativity

    International Nuclear Information System (INIS)

    This book is a quite complete route towards general relativity via special relativity with a start point at Newton's mechanics. The mathematical formulation is based on tensors. All the relativistic aspects of only classical physics - it means no quantum mechanics - are exposed. This book is divided into 3 books and each book represents a consistent knowledge of physics at a certain time in the past: in Newton's time, in the second half of the 19. century and today. The advantage of this presentation is to make the reader feels the changes over time in the concepts of time, space, gravity, cosmology. Each book is divided into 3, 4 and 5 parts which are sub-divided into numerous chapters. Book 1: Space, time and gravity in Newton's theory, with part 1: kinematics, part 2: dynamics and part 3: gravity. Book 2: Special relativity and Maxwell's theory, with part 1: kinematics, part 2: dynamics, part 3: electromagnetism and part 4: electrodynamics. And Book 3: General relativity and gravity, with part 1: curved space-time and gravity, part 2: Schwarzschild solution and black holes, part 3: general relativity and experiments, part 4: Friedman-Lemaitre solutions and cosmology, and part 5: elements or Riemann geometry. The 3. book dedicated to general relativity, tackles topics like the relationships between space-time curvature and gravity, Schwarzschild solutions and black holes, gravitational waves, Friedmann-Lemaitre solutions and cosmology, and Riemann geometry. (A.C.)

  16. Why was Relativity Accepted?

    Science.gov (United States)

    Brush, S. G.

    Historians of science have published many studies of the reception of Einstein's special and general theories of relativity. Based on a review of these studies, and my own research on the role of the light-bending prediction in the reception of general relativity, I discuss the role of three kinds of reasons for accepting relativity (1) empirical predictions and explanations; (2) social-psychological factors; and (3) aesthetic-mathematical factors. According to the historical studies, acceptance was a three-stage process. First, a few leading scientists adopted the special theory for aesthetic-mathematical reasons. In the second stage, their enthusiastic advocacy persuaded other scientists to work on the theory and apply it to problems currently of interest in atomic physics. The special theory was accepted by many German physicists by 1910 and had begun to attract some interest in other countries. In the third stage, the confirmation of Einstein's light-bending prediction attracted much public attention and forced all physicists to take the general theory of relativity seriously. In addition to light-bending, the explanation of the advance of Mercury's perihelion was considered strong evidence by theoretical physicists. The American astronomers who conducted successful tests of general relativity became defenders of the theory. There is little evidence that relativity was `socially constructed' but its initial acceptance was facilitated by the prestige and resources of its advocates.

  17. Relative accuracy evaluation.

    Directory of Open Access Journals (Sweden)

    Yan Zhang

    Full Text Available The quality of data plays an important role in business analysis and decision making, and data accuracy is an important aspect in data quality. Thus one necessary task for data quality management is to evaluate the accuracy of the data. And in order to solve the problem that the accuracy of the whole data set is low while a useful part may be high, it is also necessary to evaluate the accuracy of the query results, called relative accuracy. However, as far as we know, neither measure nor effective methods for the accuracy evaluation methods are proposed. Motivated by this, for relative accuracy evaluation, we propose a systematic method. We design a relative accuracy evaluation framework for relational databases based on a new metric to measure the accuracy using statistics. We apply the methods to evaluate the precision and recall of basic queries, which show the result's relative accuracy. We also propose the method to handle data update and to improve accuracy evaluation using functional dependencies. Extensive experimental results show the effectiveness and efficiency of our proposed framework and algorithms.

  18. Relative accuracy evaluation.

    Science.gov (United States)

    Zhang, Yan; Wang, Hongzhi; Yang, Zhongsheng; Li, Jianzhong

    2014-01-01

    The quality of data plays an important role in business analysis and decision making, and data accuracy is an important aspect in data quality. Thus one necessary task for data quality management is to evaluate the accuracy of the data. And in order to solve the problem that the accuracy of the whole data set is low while a useful part may be high, it is also necessary to evaluate the accuracy of the query results, called relative accuracy. However, as far as we know, neither measure nor effective methods for the accuracy evaluation methods are proposed. Motivated by this, for relative accuracy evaluation, we propose a systematic method. We design a relative accuracy evaluation framework for relational databases based on a new metric to measure the accuracy using statistics. We apply the methods to evaluate the precision and recall of basic queries, which show the result's relative accuracy. We also propose the method to handle data update and to improve accuracy evaluation using functional dependencies. Extensive experimental results show the effectiveness and efficiency of our proposed framework and algorithms. PMID:25133752

  19. Algorithmic Relative Complexity

    Directory of Open Access Journals (Sweden)

    Daniele Cerra

    2011-04-01

    Full Text Available Information content and compression are tightly related concepts that can be addressed through both classical and algorithmic information theories, on the basis of Shannon entropy and Kolmogorov complexity, respectively. The definition of several entities in Kolmogorov’s framework relies upon ideas from classical information theory, and these two approaches share many common traits. In this work, we expand the relations between these two frameworks by introducing algorithmic cross-complexity and relative complexity, counterparts of the cross-entropy and relative entropy (or Kullback-Leibler divergence found in Shannon’s framework. We define the cross-complexity of an object x with respect to another object y as the amount of computational resources needed to specify x in terms of y, and the complexity of x related to y as the compression power which is lost when adopting such a description for x, compared to the shortest representation of x. Properties of analogous quantities in classical information theory hold for these new concepts. As these notions are incomputable, a suitable approximation based upon data compression is derived to enable the application to real data, yielding a divergence measure applicable to any pair of strings. Example applications are outlined, involving authorship attribution and satellite image classification, as well as a comparison to similar established techniques.

  20. Is relativity right

    International Nuclear Information System (INIS)

    Arthur Eddington's influence on developments in the fields of stellar dynamics and relativity is discussed. To explain the non-spherical distribution of nearby stars in velocity space, Kapteyn proposed the two-stream hypothesis, while Schwarzchild put forward the ellipsoidal hypothesis. By his silence on Kapteyn's hypothesis, Eddington was instrumental in directing astronomers of his time away from Kapteyn's hypothesis towards the ellipsoidal hypothesis. In the field of physics, his determined advocacy of general relativity led physicists away from Lorentz and the existence of a real material vacuum. A mention is made of the fact that some new interpretation of astronomical phenomenon e.g. gravitational collapse or galaxies with binary structure is casting doubts on the rightness of relativity theory. Lorentz's theory and Einstein's theory, though treated as mathematically equivalent by many text books, are quite distinct. (M.G.B.)

  1. Dynamics and Relativity

    CERN Document Server

    Forshaw, Jeffrey

    2009-01-01

    A new title in the Manchester Physics Series, this introductory text emphasises physical principles behind classical mechanics and relativity. It assumes little in the way of prior knowledge, introducing relevant mathematics and carefully developing it within a physics context. Designed to provide a logical development of the subject, the book is divided into four sections, introductory material on dynamics, and special relativity, which is then followed by more advanced coverage of dynamics and special relativity. Each chapter includes problems ranging in difficulty from simple to challenging with?solutions for solving problems. Includes?solutions for solving problemsNumerous worked examples included throughout the bookMathematics is carefully explained and developed within a physics environmentSensitive to topics that can appear daunting or confusing

  2. Sport and International Relations

    Institute of Scientific and Technical Information of China (English)

    Zhang Yimeng

    2008-01-01

    As China takes center stage for the Beijing 2008 Olympic Games in August, enthusiasm for the Games extends far beyond the capital city. For Chinese, the Olympics is about national pride and cultural legacy. The Chinese government hopes to make this event a morale booster for the development of the whole country. And for the world, the Olympics is not just a global sporting event, but also an important platform for promoting world harmony and communication between cultures. As editor of Contemporary International Relations, I am mindful of the connection between sport and international relations. Sport today plays a highly significant role in the world, and the impact of this global phenomenon on international relations is often underestimated.

  3. Bourdieu in International Relations

    DEFF Research Database (Denmark)

    This book rethinks the key concepts of International Relations by drawing on the work of Pierre Bourdieu. The last few years have seen a genuine wave of publications promoting sociology in international relations. Scholars have suggested that Bourdieu’s vocabulary can be applied to study security......, diplomacy, migration and global environmental politics. Yet we still lack a systematic and accessible analysis of what Bourdieu-inspired IR might look like. This book provides the answer. It offers an introduction to Bourdieu’s thinking to a wider IR audience, challenges key assumptions, which currently......, Knowledge, Power, Strategy, Security, Culture, Gender, Norms, Sovereignty and Integration. The chapters demonstrate how these concepts can be reinterpreted and used in new ways when exposed to Bourdieusian logic. Challenging key pillars of IR scholarship, Bourdieu in International Relations will be of...

  4. Theory of Special Relativity

    CERN Document Server

    Zakamska, Nadia L

    2015-01-01

    Special Relativity is taught to physics sophomores at Johns Hopkins University in a series of eight lectures. Lecture 1 covers the principle of relativity and the derivation of the Lorentz transform. Lecture 2 covers length contraction and time dilation. Lecture 3 covers Minkowski diagrams, simultaneous events and causally connected events, as well as velocity transforms. Lecture 4 covers energy and momentum of particles and introduces 4-vectors. Lecture 5 covers energy and momentum of photons and collision problems. Lecture 6 covers Doppler effect and aberration. Lecture 7 covers relativistic dynamics. Optional Lecture 8 covers field transforms. The main purpose of these notes is to introduce 4-vectors and the matrix notation and to demonstrate their use in solving standard problems in Special Relativity. The pre-requisites for the class are calculus-based Classical Mechanics and Electricity & Magnetism, and Linear Algebra is highly recommended.

  5. Tensors, relativity, and cosmology

    CERN Document Server

    Dalarsson, Mirjana

    2015-01-01

    Tensors, Relativity, and Cosmology, Second Edition, combines relativity, astrophysics, and cosmology in a single volume, providing a simplified introduction to each subject that is followed by detailed mathematical derivations. The book includes a section on general relativity that gives the case for a curved space-time, presents the mathematical background (tensor calculus, Riemannian geometry), discusses the Einstein equation and its solutions (including black holes and Penrose processes), and considers the energy-momentum tensor for various solutions. In addition, a section on relativistic astrophysics discusses stellar contraction and collapse, neutron stars and their equations of state, black holes, and accretion onto collapsed objects, with a final section on cosmology discussing cosmological models, observational tests, and scenarios for the early universe. This fully revised and updated second edition includes new material on relativistic effects, such as the behavior of clocks and measuring rods in m...

  6. NgsRelate

    DEFF Research Database (Denmark)

    Korneliussen, Thorfinn Sand; Moltke, Ida

    2015-01-01

    MOTIVATION: Pairwise relatedness estimation is important in many contexts such as disease mapping and population genetics. However, all existing estimation methods are based on called genotypes, which is not ideal for next-generation sequencing (NGS) data of low depth from which genotypes cannot...... be called with high certainty. RESULTS: We present a software tool, NgsRelate, for estimating pairwise relatedness from NGS data. It provides maximum likelihood estimates that are based on genotype likelihoods instead of genotypes and thereby takes the inherent uncertainty of the genotypes into account....... Using both simulated and real data, we show that NgsRelate provides markedly better estimates for low-depth NGS data than two state-of-the-art genotype-based methods. AVAILABILITY: NgsRelate is implemented in C++ and is available under the GNU license at www.pop gen.dk/software. CONTACT: ida...

  7. 2MTF IV. A bulk flow measurement of the local Universe

    CERN Document Server

    Hong, Tao; Staveley-Smith, Lister; Scrimgeour, Morag I; Masters, Karen L; Macri, Lucas M; Koribalski, Bärbel S; Jones, D Heath; Jarrett, Tom H

    2014-01-01

    Using the 2MASS near-infrared photometry and high signal-to-noise HI 21-cm data from the Arecibo, Green Bank, Nancay, and Parkes telescopes, we calculate the redshift-independent distances and peculiar velocities of 2,018 bright inclined spiral galaxies over the whole sky. This project is part of the 2MASS Tully-Fisher survey (2MTF), aiming to map the galaxy peculiar velocity field within 100 h^{-1}Mpc, with an all-sky coverage apart from Galactic latitudes |b|< 5 deg. A \\chi^2 minimization method was adopted to analyze the Tully-Fisher peculiar velocity field in J, H and K bands, using a Gaussian filter. We combine information from the three wavebands, to provide bulk flow measurements of 310.9 +/- 33.9 km/s, 280.8 +/- 25.0 km/s, and 292.3 +/- 27.8 km/s at depths of 20 h^{-1}Mpc, 30 h^{-1}Mpc and 40 h^{-1}Mpc, respectively. Each of these bulk flow vectors points in a direction similar to those found by previous measurements. At each of the three depths, the bulk flow magnitude is consistent with predictio...

  8. Relative Kazhdan Property

    OpenAIRE

    Cornulier, Yves

    2005-01-01

    We perform a systematic investigation of Kazhdan's relative Property (T) for pairs (G,X), where G a locally compact group and X is any subset. When G is a connected Lie group or a p-adic algebraic group, we provide an explicit characterization of subsets X of G such that (G,X) has relative Property (T). In order to extend this characterization to lattices of G, a notion of "resolutions" is introduced, and various characterizations of it are given. Special attention is paid to subgroups of SU(...

  9. Rotating Stars in Relativity

    Directory of Open Access Journals (Sweden)

    Stergioulas Nikolaos

    2003-01-01

    Full Text Available Rotating relativistic stars have been studied extensively in recent years, both theoretically and observationally, because of the information they might yield about the equation of state of matter at extremely high densities and because they are considered to be promising sources of gravitational waves. The latest theoretical understanding of rotating stars in relativity is reviewed in this updated article. The sections on the equilibrium properties and on the nonaxisymmetric instabilities in f-modes and r-modes have been updated and several new sections have been added on analytic solutions for the exterior spacetime, rotating stars in LMXBs, rotating strange stars, and on rotating stars in numerical relativity.

  10. Structural Logical Relations

    DEFF Research Database (Denmark)

    Schürmann, Carsten; Sarnat, Jeffrey

    Tait's method (a.k.a. proof by logical relations) is a powerful proof technique frequently used for showing foundational properties of languages based on typed lambda-calculi. Historically, these proofs have been extremely difficult to formalize in proof assistants with weak meta-logics, such as...... Twelf, and yet they are often straightforward in proof assistants with stronger meta-logics. In this paper, we propose structural logical relations as a technique for conducting these proofs in systems with limited meta-logical strength by explicitly representing and reasoning about an auxiliary logic...

  11. Weighted Uncertainty Relations

    Science.gov (United States)

    Xiao, Yunlong; Jing, Naihuan; Li-Jost, Xianqing; Fei, Shao-Ming

    2016-03-01

    Recently, Maccone and Pati have given two stronger uncertainty relations based on the sum of variances and one of them is nontrivial when the quantum state is not an eigenstate of the sum of the observables. We derive a family of weighted uncertainty relations to provide an optimal lower bound for all situations and remove the restriction on the quantum state. Generalization to multi-observable cases is also given and an optimal lower bound for the weighted sum of the variances is obtained in general quantum situation.

  12. Annoying Danish Relatives

    DEFF Research Database (Denmark)

    Jensen de López, Kristine M.; Sundahl Olsen, Lone; Chondrigianni, V.

    2014-01-01

    This study examines the comprehension and production of subject and object relative clauses (SRCs, ORCs) by children with Specific Language Impairment (SLI) and their typically developing (TD) peers. The purpose is to investigate whether relative clauses are problematic for Danish children with SLI...... production task, as well as on SRCs compared to ORCs and produced various avoidance strategies. In the ORC context, children with SLI produced more reversal errors than the AM children, who opted for passive ORCs. These results are discussed within current theories of SLI and indicate a deficiency with the...

  13. Definable deduction relation

    Institute of Scientific and Technical Information of China (English)

    张玉平

    1999-01-01

    The nonmonotonic deduction relation in default reasoning is defined with fixed point style, which has the many-extension property that classical logic is not possessed of. These two kinds of deductions both have boolean definability property, that is, their extensions or deductive closures can be defined by boolean formulas. A generalized form of fixed point method is employed to define a class of deduction relations, which all have the above property. Theorems on definability and atomless boolean algebras in model theory are essential in dealing with this assertion.

  14. Brief introduction to relativity

    International Nuclear Information System (INIS)

    A brief, but rigorous and uncondensed, introduction to special relativity is given. The reader is assumed to be familiar with coordinate transformations in general and to have a reasonable grasp of advanced calculus and vector analysis. The subject is presented under the following topics: hypotheses underlying the Lorentz transformation, kinematics and algebraic properties of the Lorentz transformation, vectors and tensors in relativity, the electromagnetic field and Maxwell's equations, the dynamics of a particle and the Lorentz force equation, photons and relativistic optics, and applications of relativistic optics. 3 figures

  15. Relativity and its roots

    CERN Document Server

    Hoffmann, Banesh

    1998-01-01

    In this fascinating, accessible introduction to one of the most revolutionary developments in modern physics, Einstein scholar Banesh Hoffmann recounts the successive insights that led to both the special and general theories of relativity.Using simple examples from everyday life, the author presents entertaining, nontechnical demonstrations of what relativity actually means and how it has revolutionized our ideas of time and space. Starting with the geometrical and cosmological ideas of the ancient Greeks, the author traces the succession of ideas and advances that paved the way for modern p

  16. Essential dynamics and relativity

    CERN Document Server

    O'Donnell, Peter J

    2014-01-01

    Essential Dynamics & Relativity provides students with an introduction to the core aspects of dynamics and special relativity. The author reiterates important ideas and terms throughout and covers concepts that are often missing from other textbooks at this level. He also places each topic within the wider constructs of the theory, without jumping from topic to topic to illustrate a point.The first section of the book focuses on dynamics, discussing the basic aspects of single particle motion and analyzing the motion of multi-particle systems. The book also explains the dynamical behavior of b

  17. Community and Public Relations.

    Science.gov (United States)

    Sweet, Harold W.

    This brief presentation describes public relations projects of Dubuque schools to popularize athletics. Among the activities cited which are used to promote community interest in sports events are public school-private school informal matches, talks, swim-a-thons, travel and adventure nights, class banquets with popular speakers, booster clubs,…

  18. Quantum relativity theory

    International Nuclear Information System (INIS)

    A quantum relativity theory formulated in terms of Davis' quantum relativity principle is outlined. The first task in this theory as in classical relativity theory is to model space-time, the arena of natural processes. It is argued that the quantum space-time models of Banai introduced in an earlier paper is formulated in terms of Davis' quantum relativity. Then it is shown that the recently proposed classical relativistic quantum theory of Prugovecki and his corresponding classical relativistic quantum model of space-time open the way to introduce in a consistent way the quantum space-time model (the 'canonically quantized Minkowski space') proposed by Banai earlier. The main new aspect of the quantum mechanics of the quantum relativistic particles is, in this model of space-time, that it provides a true mass eigenvalue problem and, that the excited mass states of such particles can be interpreted as classifically relativistic (massive) quantum particles ('elementary particles'). The question of field theory over quantum relativistic models of space-time is also discussed. Finally, it is suggested that 'quarks' should be considered as quantum relativistic particles. (author)

  19. Effective relational dynamics

    OpenAIRE

    Hoehn, Philipp A.

    2011-01-01

    We provide a synopsis of an effective approach to the problem of time in the semiclassical regime. The essential features of this new approach to evaluating relational quantum dynamics in constrained systems are illustrated by means of a simple toy model.

  20. Modalities, Relations, and Learning

    Science.gov (United States)

    Müller, Martin Eric

    While the popularity of statistical, probabilistic and exhaustive machine learning techniques still increases, relational and logic approaches are still a niche market in research. While the former approaches focus on predictive accuracy, the latter ones prove to be indispensable in knowledge discovery.

  1. Nuclear energy related research

    International Nuclear Information System (INIS)

    The annual Research Programme Plan describes publicly funded nuclear energy related research to be carried out mainly at the Technical Research Centre of Finland (VTT) in 1992. The research is financed primarily by the Ministry of Trade and Industry (KTM), the Finnish Centre for Radiation and Nuclear Safety (STUK) and VTT itself. Other research institutes, utilities and industry also contribute to many projects

  2. Relational Information Gain

    DEFF Research Database (Denmark)

    Lippi, Marco; Jaeger, Manfred; Frasconi, Paolo;

    2011-01-01

    We introduce relational information gain, a refinement scoring function measuring the informativeness of newly introduced variables. The gain can be interpreted as a conditional entropy in a well-defined sense and can be efficiently approximately computed. In conjunction with simple greedy general...

  3. Parasite-related diarrhoeas*

    OpenAIRE

    1980-01-01

    This article reviews available knowledge on the epidemiology, pathogenesis, clinical features, immunology, diagnosis, and therapy of parasite-related diarrhoeas of public health importance, primarily amoebiasis, giardiasis, trichuriasis, strongyloidiasis, balantidiasis, coccidioses, schistosomiasis, and capillariasis. Research priorities are recommended in each of these fields with the aim of developing better means of prevention and treatment.

  4. Beijing Managing Government Relations

    Institute of Scientific and Technical Information of China (English)

    MICHAELO'NEILL

    2005-01-01

    Aroster of top-level speakers and over 100 delegates gathered at the 2nd China Government Relations Management Summit held in Beiiing at the end of March and organized by the Research Center on Transnational Corporation (CAITEC) of the Ministry of Commerce (MOFCOM). With presentations from a number of multinational corporations including Coca-Cola, Kodak,

  5. Nuclear energy related research

    Science.gov (United States)

    Rintamaa, R.

    1992-05-01

    The annual Research Program Plan describes publicly funded nuclear energy related research to be carried out mainly at the Technical Research Center of Finland (VTT) in 1992. The research is financed primarily by the Ministry of Trade and Industry (KTM), the Finnish Center for Radiation and Nuclear Safety (STUK), and VTT itself. Other research institutes, utilities, and industry also contribute to many projects.

  6. Conformal special relativity

    International Nuclear Information System (INIS)

    It is shown that the information loss/recovery theorem based on the ADS/CFT correspondence is not consistent with the stability of the Schwarzschild or Reissner-Nordstrom black holes. Nonetheless, the conformal invariance of Yang-Mills theory points to new relativity principle compatible with quantum unitarity near those black holes

  7. Nuclear energy related research

    International Nuclear Information System (INIS)

    The annual Research Programme Plan describes the publicly funded nuclear energy related research to be carried out mainly at the Technical Research Centre of Finland (VTT) in 1991. The research is financed primarily by the Ministry of Trade and Industry (KTM), the Finnish Centre for Radiation and Nuclear Safety (STUK) and VTT itself. Other research institutes, utilities and industry also contribute to many projects

  8. Nuclear energy related research

    International Nuclear Information System (INIS)

    The annual Research Programme Plan describes the publicly funded nuclear energy related research to be carried out at the Technical Research Centre of Finland (VTT) in 1990. The research is financed primarily by the Ministry of Trade and Industry (KTM), the Finnish Centre for Radiation and Nuclear Safety (STUK) and VTT itself. Utilities and industry also contribute to some projects

  9. Theory of relativity revisited

    International Nuclear Information System (INIS)

    A clear-cut and definitive experiment is outlined to test the theory of relativity. Wave versus particle theory, infinite to finite, the foundations, nonsimulaniety, inertia and acceleration, and space--time curvature are treated. Essays are included on the uncertainty principle, invariance, and four-dimensional analysis. 64 references

  10. Employment Relations in Denmark

    DEFF Research Database (Denmark)

    Madsen, Jørgen Steen; Due, Jesper Jørgen; Andersen, Søren Kaj

    2011-01-01

    Jørgen Steen Madsen, Jesper Due og Søren Kaj Andersen har skrevet et kapitel om udviklingen i dansk arbejdsmarkedsregulering til bogen International and Comparative Employment Relations, redigeret af Greg Bamber, Russell Lansbury og Nick Wailes. Bogen indeholder bidrag, der præsenterer og...

  11. Challenging Scandinavian employment relations

    DEFF Research Database (Denmark)

    Ibsen, Christian Lyhne; Larsen, Trine Pernille; Madsen, Jørgen Steen;

    2011-01-01

    employment relations in the Danish, Norwegian and Swedish public sector. In this paper, we argue that although differences exist across the Scandinavian countries, it is evident that they have managed to adopt and implement NPM-inspired reforms without dismantling their universal welfare services and strong...

  12. Om evalueringsforskningens relative autonomi

    DEFF Research Database (Denmark)

    Nørholm, Morten

    2008-01-01

    Det empiriske udgangspunkt for artiklen "Om evalueringsforskningens relative autonomi - dansk normal evalueringsforskning som et ikke-autonomt (sub)felt i magtens felt" er en række tekster af fire dominerende danske evalueringsforskere. Det teoretiske udgangspunkt er især Pierre Bourdieus teori om...

  13. Heat-Related Illnesses

    Medline Plus

    Full Text Available ... Fact Sheet Health & Safety Tips Campaigns SUBSCRIBE Emergencies A-Z Share this! Home » Emergency 101 Heat-Related ... if the person becomes unconscious. READ IN EMERGENCIES A-Z Poisoning Vomiting and Diarrhea Snake Bites Resources ...

  14. Heat-Related Illnesses

    Medline Plus

    Full Text Available ... Fact Sheet Health & Safety Tips Campaigns SUBSCRIBE Emergencies A-Z Share this! Home » Emergency 101 Heat-Related ... if the person becomes unconscious. READ IN EMERGENCIES A-Z Nosebleeds Shock Poisoning Resources Home Safety Checklist ...

  15. Related Addictive Disorders.

    Science.gov (United States)

    Buck, Tina; Sales, Amos

    This paper provides an overview of addiction related to substance abuse. It provides basic information, prevalence, diagnostic criteria, assessment tools, and treatment issues for eating disorders, compulsive gambling, sex addictions, and work addictions. Eating disorders such as anorexia nervosa and bulimia nervosa, especially affect adolescents.…

  16. Nuclear energy related research

    International Nuclear Information System (INIS)

    This annual Research Programme Plan covers the publicly funded nuclear energy related research planned to be carried out at the Technical Research Centre of Finland (VTT) in 1988. The research will be financed by the Ministry of Trade and Industry, the Finnish Centre for Radiation and Nuclear Safety, the Nordic Council of Ministers and VTT itself

  17. Relational aspects of clusters

    DEFF Research Database (Denmark)

    Gjerding, Allan Næs

    The present paper is the first preliminary account of a project being planned for 2013, focussing on the development of the biomedico cluster in North Denmark. The project focusses on the relational capabilities of the cluster in terms of a number of organizational roles which are argued to be...... necessary for the development and growth of the upcoming cluster in question....

  18. Heat-Related Illnesses

    Medline Plus

    Full Text Available ... Fact Sheet Health & Safety Tips Campaigns SUBSCRIBE Emergencies A-Z Share this! Home » Emergency 101 Heat-Related Illnesses ... if the person becomes unconscious. READ IN EMERGENCIES A-Z Your Blood Pressure Score is as Important as ...

  19. Heat-Related Illnesses

    Medline Plus

    Full Text Available ... Fact Sheet Health & Safety Tips Campaigns SUBSCRIBE Emergencies A-Z Share this! Home » Emergency 101 Heat-Related ... if the person becomes unconscious. READ IN EMERGENCIES A-Z Your Blood Pressure Score is as Important ...

  20. Relational Aggression among Students

    Science.gov (United States)

    Young, Ellie L.; Nelson, David A.; Hottle, America B.; Warburton, Brittney; Young, Bryan K.

    2011-01-01

    "Relational aggression" refers to harm within relationships caused by covert bullying or manipulative behavior. Examples include isolating a youth from his or her group of friends (social exclusion), threatening to stop talking to a friend (the silent treatment), or spreading gossip and rumors by email. This type of bullying tends to be…

  1. Nuclear energy related research

    International Nuclear Information System (INIS)

    This research programme plan for 1985 covers the nuclear energy related research planned to be carried out at the Technical Research Centre of Finland (VTT) and funded by the Ministry of Trade and Industry in Finland, the Nordic Council of Ministers and VTT

  2. Nuclear energy related research

    International Nuclear Information System (INIS)

    This annual Research Programme Plan covers the publicly funded nuclear energy related research planned to be carried out at the Technical Research Centre of Finland (VTT) in 1989. The research will be financed by the Ministry of Trade and Industry, the Finnish Centre for Radiation and Nuclear Safety, the Nordic Council of Ministers and VTT itself

  3. Heat-Related Illnesses

    Medline Plus

    Full Text Available ... Fact Sheet Health & Safety Tips Campaigns SUBSCRIBE Emergencies A-Z Share this! Home » Emergency 101 Heat-Related ... if the person becomes unconscious. READ IN EMERGENCIES A-Z Nosebleeds Head Injury Your Blood Pressure Score ...

  4. Heat-Related Illnesses

    Medline Plus

    Full Text Available ... Fact Sheet Health & Safety Tips Campaigns SUBSCRIBE Emergencies A-Z Share this! Home » Emergency 101 Heat-Related ... if the person becomes unconscious. READ IN EMERGENCIES A-Z Seizures Teeth (Dental Emergencies) Choking (Heimlich Maneuver) ...

  5. Correspondences. Equivalence relations

    International Nuclear Information System (INIS)

    We comment on sections paragraph 3 'Correspondences' and paragraph 6 'Equivalence Relations' in chapter II of 'Elements de mathematique' by N. Bourbaki in order to simplify their comprehension. Paragraph 3 exposes the ideas of a graph, correspondence and map or of function, and their composition laws. We draw attention to the following points: 1) Adopting the convention of writting from left to right, the composition law for two correspondences (A,F,B), (U,G,V) of graphs F, G is written in full generality (A,F,B)o(U,G,V) = (A,FoG,V). It is not therefore assumed that the co-domain B of the first correspondence is identical to the domain U of the second (EII.13 D.7), (1970). 2) The axiom of choice consists of creating the Hilbert terms from the only relations admitting a graph. 3) The statement of the existence theorem of a function h such that f = goh, where f and g are two given maps having the same domain (of definition), is completed if h is more precisely an injection. Paragraph 6 considers the generalisation of equality: First, by 'the equivalence relation associated with a map f of a set E identical to (x is a member of the set E and y is a member of the set E and x:f = y:f). Consequently, every relation R(x,y) which is equivalent to this is an equivalence relation in E (symmetrical, transitive, reflexive); then R admits a graph included in E x E, etc. Secondly, by means of the Hilbert term of a relation R submitted to the equivalence. In this last case, if R(x,y) is separately collectivizing in x and y, theta(x) is not the class of objects equivalent to x for R (EII.47.9), (1970). The interest of bringing together these two subjects, apart from this logical order, resides also in the fact that the theorem mentioned in 3) can be expressed by means of the equivalence relations associated with the functions f and g. The solutions of the examples proposed reveal their simplicity

  6. Relational time in physics

    International Nuclear Information System (INIS)

    Full text: Isaac Newton (1642-1727) defended in his book Mathematical Principles of Natural Philosophy, also know as Principia, published in 1687, the utilization of absolute time in physics. According to him 'absolute, true, and mathematical time, of itself, and from its own nature, flows equably without relation to anything external'. Leibniz (1646-1716), on the other hand, was against this concept and proposed relative time to replace it: 'As for my opinion, I have said more than once, that I hold space to be something merely relative, as time is; that I hold it to be an order of coexistence, as time is an order of successions'. Leibniz ideas were accepted and developed by Ernst Mach (1838-1916) in his book The Science of Mechanics, published in 1883. In this work we consider the implementation of relational time, as proposed by Leibniz and Mach, and the consequences this implementation will mean for physics as a whole. We consider some specific examples related to mechanics (Newton's bucket experiment, the flattening of the Earth, Foucault's pendulum experiment) and to electromagnetism (Ampere's force between current carrying wires, an electric charge describing a Larmor radius due to a nearby large magnet, two charges orbiting around one another). We generalize these ideas considering the principle of physical proportions (PPP), according to which no absolute magnitudes should appear in the laws of physics. We present some laws satisfying this principle and others which do not comply with it. The laws which do not satisfy the PPP should be based upon incomplete theories. We present the consequences of complete theories complying with this fundamental principle of nature. (author)

  7. Relational time in physics

    Energy Technology Data Exchange (ETDEWEB)

    Assis, A.K.T. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil)

    2011-07-01

    Full text: Isaac Newton (1642-1727) defended in his book Mathematical Principles of Natural Philosophy, also know as Principia, published in 1687, the utilization of absolute time in physics. According to him 'absolute, true, and mathematical time, of itself, and from its own nature, flows equably without relation to anything external'. Leibniz (1646-1716), on the other hand, was against this concept and proposed relative time to replace it: 'As for my opinion, I have said more than once, that I hold space to be something merely relative, as time is; that I hold it to be an order of coexistence, as time is an order of successions'. Leibniz ideas were accepted and developed by Ernst Mach (1838-1916) in his book The Science of Mechanics, published in 1883. In this work we consider the implementation of relational time, as proposed by Leibniz and Mach, and the consequences this implementation will mean for physics as a whole. We consider some specific examples related to mechanics (Newton's bucket experiment, the flattening of the Earth, Foucault's pendulum experiment) and to electromagnetism (Ampere's force between current carrying wires, an electric charge describing a Larmor radius due to a nearby large magnet, two charges orbiting around one another). We generalize these ideas considering the principle of physical proportions (PPP), according to which no absolute magnitudes should appear in the laws of physics. We present some laws satisfying this principle and others which do not comply with it. The laws which do not satisfy the PPP should be based upon incomplete theories. We present the consequences of complete theories complying with this fundamental principle of nature. (author)

  8. Constructivism and International Relations

    DEFF Research Database (Denmark)

    critique of the realist school, the conceptualism of identity, and his teleological theory of history. Wendt's reply is not limited to rebuttal only. For the first time, he develops his recent idea of quantum social science, as well as its implications for theorising international relations. This unique......This new book unites in one volume some of the most prominent critiques of Alexander Wendt's constructivist theory of international relations and includes the first comprehensive reply by Wendt. Partly reprints of benchmark articles, partly new original critiques, the critical chapters are informed...... by a wide array of contending theories ranging from realism to poststructuralism. The collected leading theorists critique Wendt's seminal book Social Theory of International Politics and his subsequent revisions. They take issue with the full panoply of Wendt's approach, such as his alleged positivism, his...

  9. Bourdieu in International Relations

    DEFF Research Database (Denmark)

    . The chapters demonstrate how these concepts can be reinterpreted and used in new ways when exposed to Bourdieusian logic. Challenging key pillars of IR scholarship, Bourdieu in International Relations will be of interest to critical theorists, and scholars of IR theory.......The last few years have seen a genuine wave of publications promoting sociology in international relations. Scholars have suggested that Bourdieu’s vocabulary can be applied to study security, diplomacy, migration and global environmental politics. Yet we still lack a systematic and accessible...... concepts in the field. The book brings together a select group of leading IR scholars who draw on both theoretical and empirical insights from Bourdieu. Each chapter covers one central concept in IR: Methodology, Knowledge, Power, Strategy, Security, Culture, Gender, Norms, Sovereignty and Integration...

  10. Theorising International Monetary Relations

    DEFF Research Database (Denmark)

    Leander, Anna

    2015-01-01

    on Cohen's treatment of electronic money and its significance for the Politics of International Monetary Relations. The first question posed is about ontology, the second about agency and the third about the scope of politics. The three questions are raised as a conversation in which arguments...... and counterarguments are advanced. The questions are therefore posed with Cohen's contributions to theorizing the political significance of materiality as their point of departure. They are formulated as a consequence of bringing these contributions in relation to insights from the Social Studies of Finance. From...... this perspective it would seem that a more far reaching engagement with materiality (in terms of ontology, agency and epistemology) is necessary to capture its political significance for international monetary politics and currency hierarchies. The article does not conclude in conventional fashion but purposefully...

  11. Numerical Relativity Beyond Astrophysics

    CERN Document Server

    Garfinkle, David

    2016-01-01

    Though the main applications of computer simulations in relativity are to astrophysical systems such as black holes and neutron stars, nonetheless there are important applications of numerical methods to the investigation of general relativity as a fundamental theory of the nature of space and time. This paper gives an overview of some of these applications. In particular we cover (i) investigations of the properties of spacetime singularities such as those that occur in the interior of black holes and in big bang cosmology. (ii) investigations of critical behavior at the threshold of black hole formation in gravitational collapse. (iii) investigations inspired by string theory, in particular analogs of black holes in more than 4 spacetime dimensions and gravitational collapse in spacetimes with a negative cosmological constant.

  12. Journalism of Relation

    DEFF Research Database (Denmark)

    Blaagaard, Bolette

    -defined as theory and practice of production of cultural memory and social imaginaries of gendered, ethnic, religious, national and ‘racial’ differences. At the core of the argument here is a critique of the journalistic use of ‘objectivity’. This use hides the journalistic subjectivity by splitting the...... phenomenological approach to difference, perception should not be understood as interchangeable with visualisation. It is rather an understanding that creates strong ties to consciousness and experience. Drawing in the whole of personal experience and consciousness of difference phenomenology presents a theory of...... the self-other relation which is simultaneously personal and political. Secondly, the dissertation relates the phenomenological ‘race’ and gender debates to the societal and productive context of contemporary European and ‘western’ globalised and mediated culture and politics. Journalism is re...

  13. Beyond Einstein's General Relativity

    OpenAIRE

    Lobo, Francisco S N

    2014-01-01

    Modern astrophysical and cosmological models are plagued with two severe theoretical difficulties, namely, the dark energy and the dark matter problems. Relative to the former, high-precision observational data have confirmed with startling evidence that the Universe is undergoing a phase of accelerated expansion. This phase, one of the most important and challenging current problems in cosmology, represents a new imbalance in the governing gravitational equations. Several candidates, respons...

  14. Matter in general relativity

    Science.gov (United States)

    Ray, J. R.

    1982-01-01

    Two theories of matter in general relativity, the fluid theory and the kinetic theory, were studied. Results include: (1) a discussion of various methods of completing the fluid equations; (2) a method of constructing charged general relativistic solutions in kinetic theory; and (3) a proof and discussion of the incompatibility of perfect fluid solutions in anisotropic cosmologies. Interpretations of NASA gravitational experiments using the above mentioned results were started. Two papers were prepared for publications based on this work.

  15. Gauge and General Relativity

    OpenAIRE

    Iftime, M. D.

    2006-01-01

    One of the main features of covariant theories, in particular general relativity, is that the field equation possesses gauge freedom associated with global diffeomorphisms of the underlying manifold. I shall explain here how the hole argument is a reflection of this gauge freedom. Finally I shall point out some implications of the hole argument and extend the hole argument to the case of permutable theories. As covariant theories provides a general mathematical framework for classical physics...

  16. Proactive media relations

    International Nuclear Information System (INIS)

    This paper looks at a proactive approach to media relations whereby news events are planned, shaped, and timed according to their impact and significance. Focus is given to both written materials and media training. Recommendations are given on why media training should be used as well as how press releases and fact sheets should be written to assist reporters in covering complex technologies and project milestones

  17. Nonlocal Special Relativity

    OpenAIRE

    Mashhoon, Bahram

    2008-01-01

    In the special theory of relativity, Lorentz invariance is extended in Minkowski spacetime from ideal inertial observers to actual observers by means of the hypothesis of locality, which postulates that accelerated observers are always pointwise inertial. A critical examination of the locality assumption reveals its domain of validity: it is true for pointwise coincidences, but is in conflict with wave-particle duality. To remedy this situation, a nonlocal theory of accelerated systems is pre...

  18. Status of numerical relativity

    Indian Academy of Sciences (India)

    Masaru Shibata

    2004-10-01

    I describe the current status of numerical relativity from my personal point of view. Here, I focus mainly on explaining the numerical implementations necessary for simulating general relativistic phenomena such as the merger of compact binaries and stellar collapse, emphasizing the well-developed current status of such implementations that enable simulations for several astrophysical phenomena. Some of our latest results for simulation of binary neutron star mergers are briefly presented.

  19. Relative Risk Aversion

    OpenAIRE

    James S. Dyer; Rakesh K. Sarin

    1982-01-01

    An individual's preference for risky alternatives is influenced by the strength of preference he feels for the consequences and his attitude toward risk taking. Conventional measures of risk attitude confound these two factors. In this paper we formally separate these factors and explore how this separation might significantly enhance our understanding of decision making under risk. We introduce a new measure of risk attitude defined relative to strength of preference. This measure is based o...

  20. Numerical Relativity: A review

    OpenAIRE

    Lehner, Luis

    2001-01-01

    Computer simulations are enabling researchers to investigate systems which are extremely difficult to handle analytically. In the particular case of General Relativity, numerical models have proved extremely valuable for investigations of strong field scenarios and been crucial to reveal unexpected phenomena. Considerable efforts are being spent to simulate astrophysically relevant simulations, understand different aspects of the theory and even provide insights in the search for a quantum th...

  1. Teleseismic magnitude relations

    OpenAIRE

    Markus Båth

    2010-01-01

    Using available sets of magnitude determinations, primarily from Uppsala seismological bulletin, various extensions are made of the Zurich magnitude recommendations of 1967. Thus, body-wave magnitude (m) and surface-wave magnitudes (M) are related to each other for 12 different earthquake regions as well as world-wide. Depth corrections for M are derived for all focal depths. Formulas are developed which permit calculation of M also from vertical component long-period seismographs. Body-wave ...

  2. Asteroseismic stellar activity relations

    CERN Document Server

    Bonanno, A; Karoff, C

    2014-01-01

    In asteroseismology an important diagnostic of the evolutionary status of a star is the small frequency separation which is sensitive to the gradient of the mean molecular weight in the stellar interior. It is thus interesting to discuss the classical age-activity relations in terms of this quantity. Moreover, as the photospheric magnetic field tends to suppress the amplitudes of acoustic oscillations, it is important to quantify the importance of this effect by considering various activity indicators. We propose a new class of age-activity relations that connects the Mt. Wilson $S$ index and the average scatter in the light curve with the small frequency separation and the amplitude of the p-mode oscillations. We used a Bayesian inference to compute the posterior probability of various empirical laws for a sample of 19 solar-like active stars observed by the Kepler telescope. We demonstrate the presence of a clear correlation between the Mt. Wilson $S$ index and the relative age of the stars as indicated by ...

  3. General Relativity and Gravitation

    Science.gov (United States)

    Ashtekar, Abhay; Berger, Beverly; Isenberg, James; MacCallum, Malcolm

    2015-07-01

    Part I. Einstein's Triumph: 1. 100 years of general relativity George F. R. Ellis; 2. Was Einstein right? Clifford M. Will; 3. Cosmology David Wands, Misao Sasaki, Eiichiro Komatsu, Roy Maartens and Malcolm A. H. MacCallum; 4. Relativistic astrophysics Peter Schneider, Ramesh Narayan, Jeffrey E. McClintock, Peter Mészáros and Martin J. Rees; Part II. New Window on the Universe: 5. Receiving gravitational waves Beverly K. Berger, Karsten Danzmann, Gabriela Gonzalez, Andrea Lommen, Guido Mueller, Albrecht Rüdiger and William Joseph Weber; 6. Sources of gravitational waves. Theory and observations Alessandra Buonanno and B. S. Sathyaprakash; Part III. Gravity is Geometry, After All: 7. Probing strong field gravity through numerical simulations Frans Pretorius, Matthew W. Choptuik and Luis Lehner; 8. The initial value problem of general relativity and its implications Gregory J. Galloway, Pengzi Miao and Richard Schoen; 9. Global behavior of solutions to Einstein's equations Stefanos Aretakis, James Isenberg, Vincent Moncrief and Igor Rodnianski; Part IV. Beyond Einstein: 10. Quantum fields in curved space-times Stefan Hollands and Robert M. Wald; 11. From general relativity to quantum gravity Abhay Ashtekar, Martin Reuter and Carlo Rovelli; 12. Quantum gravity via unification Henriette Elvang and Gary T. Horowitz.

  4. Teleseismic magnitude relations

    Directory of Open Access Journals (Sweden)

    Markus Båth

    2010-02-01

    Full Text Available Using available sets of magnitude determinations, primarily from Uppsala seismological bulletin, various extensions are made of the Zurich magnitude recommendations of 1967. Thus, body-wave magnitude (m and surface-wave magnitudes (M are related to each other for 12 different earthquake regions as well as world-wide. Depth corrections for M are derived for all focal depths. Formulas are developed which permit calculation of M also from vertical component long-period seismographs. Body-wave magnitudes from broad-band and narrow-band short-period seismographs are compared and relations deduced. Applications are made both to underground nuclear explosions and to earthquakes. The possibilities of explosion-earthquake discrimination on the basis of magnitudes are examined, as well as the determination of explosive yield from magnitudes. For earthquakes, relations between magnitudes of main earthquakes and largest aftershocks are investigated. A world-wide station network for more homogeneous magnitude determinations is suggested in order to provide the necessary reference system.

  5. Forces in general relativity

    International Nuclear Information System (INIS)

    Many textbooks dealing with general relativity do not demonstrate the derivation of forces in enough detail. The analyses presented herein demonstrate straightforward methods for computing forces by way of general relativity. Covariant divergence of the stress-energy-momentum tensor is used to derive a general expression of the force experienced by an observer in general coordinates. The general force is then applied to the local co-moving coordinate system of a uniformly accelerating observer, leading to an expression of the inertial force experienced by the observer. Next, applying the general force in Schwarzschild coordinates is shown to lead to familiar expressions of the gravitational force. As a more complex demonstration, the general force is applied to an observer in Boyer-Lindquist coordinates near a rotating, Kerr black hole. It is then shown that when the angular momentum of the black hole goes to zero, the force on the observer reduces to the force on an observer held stationary in Schwarzschild coordinates. As a final consideration, the force on an observer moving in rotating coordinates is derived. Expressing the force in terms of Christoffel symbols in rotating coordinates leads to familiar expressions of the centrifugal and Coriolis forces on the observer. It is envisioned that the techniques presented herein will be most useful to graduate level students, as well as those undergraduate students having experience with general relativity and tensor analysis.

  6. Relative permeability through fractures

    Energy Technology Data Exchange (ETDEWEB)

    Diomampo, Gracel, P.

    2001-08-01

    The mechanism of two-phase flow through fractures is of importance in understanding many geologic processes. Currently, two-phase flow through fractures is still poorly understood. In this study, nitrogen-water experiments were done on both smooth and rough parallel plates to determine the governing flow mechanism for fractures and the appropriate methodology for data analysis. The experiments were done using a glass plate to allow visualization of flow. Digital video recording allowed instantaneous measurement of pressure, flow rate and saturation. Saturation was computed using image analysis techniques. The experiments showed that gas and liquid phases flow through fractures in nonuniform separate channels. The localized channels change with time as each phase path undergoes continues breaking and reforming due to invasion of the other phase. The stability of the phase paths is dependent on liquid and gas flow rate ratio. This mechanism holds true for over a range of saturation for both smooth and rough fractures. In imbibition for rough-walled fractures, another mechanism similar to wave-like flow in pipes was also observed. The data from the experiments were analyzed using Darcy's law and using the concept of friction factor and equivalent Reynold's number for two-phase flow. For both smooth- and rough-walled fractures a clear relationship between relative permeability and saturation was seen. The calculated relative permeability curves follow Corey-type behavior and can be modeled using Honarpour expressions. The sum of the relative permeabilities is not equal one, indicating phase interference. The equivalent homogeneous single-phase approach did not give satisfactory representation of flow through fractures. The graphs of experimentally derived friction factor with the modified Reynolds number do not reveal a distinctive linear relationship.

  7. A Concurrent Logical Relation

    DEFF Research Database (Denmark)

    Birkedal, Lars; Sieczkowski, Filip; Thamsborg, Jacob Junker

    2012-01-01

    We present a logical relation for showing the correctness of program transformations based on a new type-and-effect system for a concurrent extension of an ML-like language with higher-order functions, higher-order store and dynamic memory allocation. We show how to use our model to verify a number...... expressions. To the best of our knowledge, this is the first such result for a concurrent higher-order language with higher-order store and dynamic memory allocation....

  8. DEEPENING ECONOMIC RELATIONS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Inaugurated as a vehicle to improve cooperation between China and the African continent in 2000, the annual Forum on China-Africa Cooperation has become a platform for communication and cooperation. On the eve of the Beijing Summit and the Third Ministerial Conference of the forum, to be held in early November, Beijing Review reporter Liu Wei spoke to Zhou Yabin, head of the West Asia and Africa Affairs Department of the Chinese Ministry of Commerce (MOFCOM), about Sino-African trade and the forum’s agenda on promoting the economic relations between China and Africa.

  9. Inferring deterministic causal relations

    OpenAIRE

    Daniusis, Povilas; Janzing, Dominik; Mooij, Joris; Zscheischler, Jakob; Steudel, Bastian; Zhang, Kun; Schoelkopf, Bernhard

    2012-01-01

    We consider two variables that are related to each other by an invertible function. While it has previously been shown that the dependence structure of the noise can provide hints to determine which of the two variables is the cause, we presently show that even in the deterministic (noise-free) case, there are asymmetries that can be exploited for causal inference. Our method is based on the idea that if the function and the probability density of the cause are chosen independently, then the ...

  10. Relatório

    OpenAIRE

    Ferreira, Vera Lúcia Marçalo

    2011-01-01

    O presente relatório tem um duplo propósito, descrever o percurso realizado no âmbito dos módulos de Estágio preconizados pelo plano de estudos do Curso de Mestrado em Enfermagem de Natureza Profissional na área de Especialização em Enfermagem Médico- Cirúrgica, do Instituto de Ciências da Saúde, Universidade Católica Portuguesa, e evidenciar o desenvolvimento de competências de Enfermeira Especialista decorrentes deste percurso, as quais serão mobilizadas para a minha práxis p...

  11. Tachyons in general relativity

    International Nuclear Information System (INIS)

    We consider the motion of tachyons (faster-than-light particles) in the framework of general relativity. An important feature is the large contribution of low energy tachyons to the energy-momentum tensor. We also calculate the gravitational field produced by tachyons in particular geometric arrangements; and it appears that there could be self-cohering bundles of such matter. This leads us to suggest that such theoretical ideas might be relevant to major problems (dark matter and dark energy) in current cosmological models.

  12. Nuclear public relations campaign

    Energy Technology Data Exchange (ETDEWEB)

    1983-01-01

    A two-day hearing to investigate DOE's participation in a $30 million nuclear public relations program at a time when the country is asked to decrease spending and in conjunction with similar efforts by the nuclear industry focused on the issue of whether ratepayers or shareholders should finance the effort. Shelby Brewer, Assistant Secretary for Nuclear Energy, defended the expenditures as a response to public demand for information and the need to correct misinformation. The testimony of 14 other witnesses includes the views of citizen and professional groups, utilities, and government agencies. Their testimony is followed by additional material submitted for the record. (DCK)

  13. Modified Josephson Relation

    OpenAIRE

    Kolacek, Jan; Lipavsky, Pavel

    2003-01-01

    For type II superconductors, Josephson has shown that vortices moving with velocity v_L create an effective electric field E'=-v_L x B. By definition the effective electric field is gradient of the electrochemical potential, what is the quantity corresponding to voltage observed with the use of Ohmic contacts. It relates to the true electric field E via the local chemical potential mu as E'=E - grad(mu)/e. We argue that at low temperatures the true electric field in the bulk can be approximat...

  14. Modelling dense relational data

    DEFF Research Database (Denmark)

    Herlau, Tue; Mørup, Morten; Schmidt, Mikkel Nørgaard;

    2012-01-01

    Relational modelling classically consider sparse and discrete data. Measures of influence computed pairwise between temporal sources naturally give rise to dense continuous-valued matrices, for instance p-values from Granger causality. Due to asymmetry or lack of positive definiteness they are not...... naturally suited for kernel K-means. We propose a generative Bayesian model for dense matrices which generalize kernel K-means to consider off-diagonal interactions in matrices of interactions, and demonstrate its ability to detect structure on both artificial data and two real data sets....

  15. Dasatinib-Related Chylothorax

    Directory of Open Access Journals (Sweden)

    Yen Min Huang

    2015-03-01

    Full Text Available Dasatinib is a potent second-generation tyrosine kinase inhibitor for the treatment of chronic myeloid leukemia. The most common adverse event associated with dasatinib therapy is fluid retention, including pleural effusion. Dasatinib-related chylothorax has rarely been reported. The clinical manifestations, pathophysiology, management, and prognosis are not fully understood. Here we report a 40-year-old woman presenting with chylothorax following dasatinib use. We propose the hypothesis of its mechanism as well as offering a review of the relevant literature.

  16. Relativity in Introductory Physics

    CERN Document Server

    Baylis, W E

    2004-01-01

    A century after its formulation by Einstein, it is time to incorporate special relativity early in the physics curriculum. The approach advocated here employs a simple algebraic extension of vector formalism that generates Minkowski spacetime, displays covariant symmetries, and enables calculations of boosts and spatial rotations without matrices or tensors. The approach is part of a comprehensive geometric algebra with applications in many areas of physics, but only an intuitive subset is needed at the introductory level. The approach and some of its extensions are given here and illustrated with insights into the geometry of spacetime.

  17. Theory of relations

    CERN Document Server

    Fraïssé, R

    2011-01-01

    The first part of this book concerns the present state of the theory of chains (= total or linear orderings), in connection with some refinements of Ramsey's theorem, due to Galvin and Nash-Williams. This leads to the fundamental Laver's embeddability theorem for scattered chains, using Nash-Williams' better quasi-orderings, barriers and forerunning.The second part (chapters 9 to 12) extends to general relations the main notions and results from order-type theory. An important connection appears with permutation theory (Cameron, Pouzet, Livingstone and Wagner) and with logics (existence criter

  18. Negotiation within labor relations

    Directory of Open Access Journals (Sweden)

    Iulia BĂDOI

    2014-06-01

    Full Text Available Negotiation is the process we use in order to obtain things that we want and are controlled by others. Any desire we intend to fulfill, any need that we are obliged to meet is a potential bargaining situations. Between groups and individuals, negotiation occurs naturally, as some have one thing that the other wants and is willing to bargain to get it. More or less we are all involved in negotiations: closing a contract, buying a thing, obtaining sponsorships, collective decision making, conflict resolution, agreement on work plans. Within the field of labor relations, negotiation can occur on the occasion of closing / amending employment contracts or in order to regulate employment or work relations. Moreover, used properly, the negotiation can be an effective tool for solving labor disputes, with benefits for both involved parties. This paper aims to present negotiating principles and steps to follow in planning and preparing negotiations and the negotiating techniques that can lead to a successful negotiation based on a well-developed plan.

  19. General relativity and matter

    International Nuclear Information System (INIS)

    The primary aim of this monograph is to present the results of a research study that attempts to fully unify the logical and the mathematical aspects of the theory of general relativity. It views the theory of general relativity not as a theory only of the gravitational force manifestation of matter, but rather as a general theory of matter. This approach proceeds by attempting to fully incorporate the Mach principle into the formalism so as to fuse the gravitational and electromagnetic force manifestations of matter with its inertial manifestations. With this approach it is shown that in accordance with Einstein's original motivation toward a unified field theory, generalization occurs that adds to the predictive capacity of the theory, incorporating the physics of the domain of elementary matter (of microscopic physics) with the domain of astronomy and cosmology; thus this approach unifies manifestations of matter from the domain of fermis (and less) to that of light-years (and greater) in terms of a nonsingular field theory of matter. (Auth.)

  20. My relational self psychology.

    Science.gov (United States)

    Teicholz, Judith Guss

    2009-04-01

    In this article, I suggest recent sources of influence on psychoanalysis and describe a contemporary relational self psychology that is my personal attempt at integration. Even with this integration, I struggle to find the right "therapeutic" balance between my essential but imperfect instrument for empathic listening, on the one hand, and the risks of authentic engagement, on the other. These dialectical tensions in me mirror those in the psychoanalytic community as a whole, poised between a scientifically based practice and a healing "art"--or between a complex but teachable methodology or discipline-and an ordinary (yet extraordinary) human relationship in which spontaneity and even improvisation play a role. Complicating this balancing act, there is new evidence from neuroscientists, attachment theorists, and infant-caregiver researchers that, from birth onward, bidirectional influences on brain and psychic development create contingent and unpredictable outcomes in every intimately related dyad. Thus, the contemporary analyst must expect to be changed by the work and--while taking full responsibility for his or her own contribution--must recognize patient and analyst as co-creators of the psychoanalytic project. At the same time that we now recognize contingency, complexity, and chaos at the heart of human minds and relationships, we also acknowledge the central importance of a sense of continuity and coherence as the individual undertakes the pursuit of goals and relationships in life. What kind of relationship can facilitate these qualities in the sense of self? That is the question that this article undertakes to answer. PMID:19379236

  1. Public relations strategy

    International Nuclear Information System (INIS)

    NIMBY (Not In My Back Yard) syndrome has become a major problem in the field of environmental planning. Also in Slovenia. Agency for Radwaste management was established by the Slovene government in 1991. Our main objective is to provide the final disposal of radioactive waste in Slovenia. Overcoming the NIMBY syndrome is therefore the primary aim of Agency's PR (public relations) strategy. Agency's public relations strategy was prepared in 1993. After very unpleasant experience with NIMBY syndrome in local community where one of the potential locations for low and intermediate level repository was identified the strategy was renewed in 1994. It is divided into two parts: information and education. The first one includes providing information to the media, surveys of press clippings, interviews, press conferences, public opinion polls and publishing articles. Agency's first task in the field of education was to prepare different materials like: leaflets, Agency's newspaper and videos. Materials were distributed to various target publics. There is also a special program of lectures for youngsters. All those activities and projects have been successfully realized within the last year. Plans of PR activities for this year are focused on informing the local community about remediation of temporary storage of radioactive waste near village Zavratec. Other new projects are also under preparation like: new leaflets, presentation on Internet, journalist's guide to rad waste management, most frequently asked questions and answers. (author)

  2. RELATIVITY AND SUSTAINABLE DEVELOPMENT

    Institute of Scientific and Technical Information of China (English)

    YE Dai-fu

    2004-01-01

    From the realism of science, and taking the guide of EINSTEIN's Relativity as guide, this article called in question the present theory of the sustainable development by the rational thinking of philosophy and a close logic inference. It is found that there are many paradoxes to the theory. Through more deepening and meticulous inference, we arrived at philosophic language of science about the sustainable development. The sustainable development is "non-sustainable development", and the non-sustainable development is "the best sustainable development''. While carrying out philosophical principle thinking and repeating science demonstration for the sustainable development, this article got further confirmation that the existence of human being at the minimum environment cost may help them obtain motive power of the sustainable development. In fact, this foundation motive power exists in the flow of development in different organization levels, meanwhile it exists in strategy of intuition living of the ancient people. Only in relative lower environment cost to live can we get the support system of science for the sustainable development, and be able really to achieve the basic goal of the sustainable development.

  3. Relativity of GPS measurement

    International Nuclear Information System (INIS)

    The relativity of Global Positioning System (GPS) pseudorange measurements is explored within the geometrical optics approximation in the curved space-time near Earth. A space-time grid for navigation is created by the discontinuities introduced in the electromagnetic field amplitude by the P-code broadcast by the GPS satellites. We compute the world function of space-time near Earth, and we use it to define a scalar phase function that describes the space-time grid. We use this scalar phase function to define the measured pseudorange, which turns out to be a two-point space-time scalar under generalized coordinate transformations. Though the measured pseudorange is an invariant, it depends on the world lines of the receiver and satellite. While two colocated receivers measure two different pseudoranges to the same satellite, they obtain the correct position and time, independent of their velocity. We relate the measured pseudorange to the geometry of space-time and find corrections to the conventional model of the pseudorange that are on the order of the gravitational radius of the Earth

  4. Authenticity in Employment Relations

    DEFF Research Database (Denmark)

    Tackney, Charles Thomas

    This research takes up the concept of authenticity as a criterion variable for theology of the workplace analysis, a domain which explores employment parameters in light of religious teaching on the social question at national, organizational or firm-specific levels. Following a review of the con......This research takes up the concept of authenticity as a criterion variable for theology of the workplace analysis, a domain which explores employment parameters in light of religious teaching on the social question at national, organizational or firm-specific levels. Following a review......, it becomes possible to specify employment relations parameters between the indirect and direct employer and employees in a manner that will ensure working conditions consistent with these traditions, substantially enhancing the prospect of authenticity in employment relations. This theology of the workplace...... analysis should complement and support corporate social responsibility, management spirituality, authentic leadership / authentic follower, and other secular research by offering a research methods bridge between empirically grounded theology and secular studies, with the common goal of improving workplace...

  5. Work related shoulder disorders

    DEFF Research Database (Denmark)

    Svendsen, Susanne Wulff; Bonde, Jens Peter; Mathiassen, S.E.;

    2004-01-01

    Aims: To determine quantitative exposure-response relations between work with highly elevated arms and supraspinatus tendinitis, shoulder pain with disability, and shoulder pain without disability. Methods: A cross sectional study was conducted in a historical cohort of 1886 males from three...... occupational groups. Exposure measurements were performed for four consecutive working days in a random sample of 72 currently employed subjects. Individual work histories were obtained by questionnaire and register data. Health status was ascertained by physical examination blinded towards exposure...... and symptoms. Data were analysed by generalised estimating equation and multiple logistic regression with adjustment for potential confounders. Results: For current upper arm elevation above 90°, a duration increment of 1% of the daily working hours was associated with odds ratios of 1.23 (95% CI 1.10 to 1...

  6. Inferring deterministic causal relations

    CERN Document Server

    Daniusis, Povilas; Mooij, Joris; Zscheischler, Jakob; Steudel, Bastian; Zhang, Kun; Schoelkopf, Bernhard

    2012-01-01

    We consider two variables that are related to each other by an invertible function. While it has previously been shown that the dependence structure of the noise can provide hints to determine which of the two variables is the cause, we presently show that even in the deterministic (noise-free) case, there are asymmetries that can be exploited for causal inference. Our method is based on the idea that if the function and the probability density of the cause are chosen independently, then the distribution of the effect will, in a certain sense, depend on the function. We provide a theoretical analysis of this method, showing that it also works in the low noise regime, and link it to information geometry. We report strong empirical results on various real-world data sets from different domains.

  7. Sleep-related laryngospasm

    Directory of Open Access Journals (Sweden)

    Flavio S. Aloe

    1995-03-01

    Full Text Available Seven patients (mean age 46.6; range 33-58; 6M.1F presented with sleep-related choking episodes and were found to have features in common that distinguished them from other known causes of choking episodes during sleep. The characteristic features include: an awakening from sleep with an acute choking sensation, stridor, panic, tachycardia, short duration of episode Gess than 60 seconds, infrequent episodes (typically less than 1 per month, and absence of any known etiology. The disorder most commonly occurs in middle-aged males who are otherwise healthy. In one patient an episode of laryngospasm was polysomnographically documented to occur during stage 3. The clinical features and the polysomnographic findings suggest spasm of the vocal cords of unknown etiology.

  8. Strains in general relativity

    International Nuclear Information System (INIS)

    The definition of relative accelerations and strains among a set of comoving particles is studied in connection with the geometric properties of the frame adapted to a 'fiducial observer'. We find that a relativistically complete and correct definition of strains must take into account the transport law of the chosen spatial triad along the observer's congruence. We use special congruences of (accelerated) test particles in some familiar spacetimes to elucidate such a point. The celebrated idea of Szekeres' compass of inertia, arising when studying geodesic deviation among a set of free-falling particles, is here generalized to the case of accelerated particles. In doing so we have naturally contributed to the theory of relativistic gravity gradiometer. Moreover, our analysis was made in an observer-dependent form, a fact that would be very useful when thinking about general relativistic tests on space stations orbiting compact objects like black holes and also in other interesting gravitational situations

  9. Communication and external relations

    International Nuclear Information System (INIS)

    A company's identity is what it really is, whereas its image is what others perceive or think it is. Therefore, it should suffice to simply combine these two concepts-identity and image-to simplify communication activities. However, identity and image are complex, varying concepts that are conditioned by environment, opinions, expectations, attitudes, market evolution and many other factors. In Cofrentes, we have always been aware of the difficulties involved in successful communication at all levels and, therefore, from the very beginning, even before the Plant was started up, channels were established for public service and relations with all the entities of Cofrentes NPP physical, human and institutional environment in its three possible spheres of influence at the local, provincial and national levels. (Author)

  10. LAMA2-related myopathy

    DEFF Research Database (Denmark)

    Løkken, Nicoline; Born, Alfred Peter; Duno, Morten;

    2015-01-01

    INTRODUCTION: Muscular dystrophy caused by LAMA2-gene mutations is an autosomal recessive disease typically presenting as a severe, early-onset congenital muscular dystrophy (CMD). However, milder cases with a limb-girdle type muscular dystrophy (LGMD) have been described. METHODS: In this study......, we assessed the frequency and phenotypic spectrum of LAMA2-related muscular dystrophy in CMD (n = 18) and LGMD2 (n = 128) cohorts identified in the last 15 years in eastern Denmark. The medical history, brain-MRI, muscle pathology, muscle laminin-α2 expression, and genetic analyses were assessed...... dystrophy and its prevalence in an LGMD2 cohort, which indicates that LAMA2 muscular dystrophy should be included in the LGMD2 nomenclature....

  11. [Sleep related movement disorders].

    Science.gov (United States)

    Suzuki, Keisuke; Miyamoto, Masayuki; Miyamoto, Tomoyuki; Hirata, Koichi

    2015-06-01

    Sleep related movement disorders (SRMD) are characterized by simple, stereotyped movements occur during sleep, with the exception of restless legs syndrome (RLS). RLS has the following essential features; an urge to move the legs usually accompanied by uncomfortable sensation in the legs, improvement of symptoms after movement (non-stereotypical movements, such as walking and stretching, to reduce symptoms), and symptoms occur or worsen during periods of rest and in the evening and night. However, RLS is closely associated with periodic limb movement, which shows typical stererotyped limb movements. In the International Classification of Sleep Disorders, 3rd edition, sleep disturbances or daytime symptoms are prerequiste for a diagnosis of SRMD. We here review diagnosis and treatment of SRMD. PMID:26065126

  12. The Algebra of -relations

    Indian Academy of Sciences (India)

    Vijay Kodiyalam; R Srinivasan; V S Sunder

    2000-08-01

    In this paper, we study a tower $\\{A^G_n(d):n≥ 1\\}$ of finite-dimensional algebras; here, represents an arbitrary finite group, denotes a complex parameter, and the algebra $A^G_n(d)$ has a basis indexed by `-stable equivalence relations' on a set where acts freely and has 2 orbits. We show that the algebra $A^G_n(d)$ is semi-simple for all but a finite set of values of , and determine the representation theory (or, equivalently, the decomposition into simple summands) of this algebra in the `generic case'. Finally we determine the Bratteli diagram of the tower $\\{A^G_n(d): n≥ 1\\}$ (in the generic case).

  13. Living Related Liver Transplantation

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Living Related Liver Transplantation (LRLT)is a new strategy, which offers the option of a lifesaving procedure to patients suffering from end - stage liver disease, and the experience indicates that the results are better than cadaveric liver transplantation. It promises to decrease the waiting time for liver transplantation significantly and to reduce the number of patients dying on the waiting list. The selection of a suitable donor and the techniques of operation are of paramount importance for LRLT to minimize the risk for the recipient and the donor, and achieve better outcome for patient. 1 -year recipient survival rate of LRLT is over 90% and 5 -year recipient survival rate of LRLT is about 80%. LRLT has been becoming standard and normal operation in many western transplant centers.

  14. Strains in General Relativity

    CERN Document Server

    Bini, Donato; Geralico, Andrea

    2014-01-01

    The definition of relative accelerations and strains among a set of comoving particles is studied in connection with the geometric properties of the frame adapted to a "fiducial observer." We find that a relativistically complete and correct definition of strains must take into account the transport law of the chosen spatial triad along the observer's congruence. We use special congruences of (accelerated) test particles in some familiar spacetimes to elucidate such a point. The celebrated idea of Szekeres' compass of inertia, arising when studying geodesic deviation among a set of free-falling particles, is here generalized to the case of accelerated particles. In doing so we have naturally contributed to the theory of relativistic gravity gradiometer. Moreover, our analysis was made in an observer-dependent form, a fact that would be very useful when thinking about general relativistic tests on space stations orbiting compact objects like black holes and also in other interesting gravitational situations.

  15. Can Relations be Designed?

    DEFF Research Database (Denmark)

    Skou, Niels Peter; Mikkelsen, Mette

    This paper examines the role of design methods in a social innovation project on a Danish Institution for severely physically and mentally handicapped people. The project was focused on ‘designing’ new or better relations between the residents at the institution and the civil society. During the...... project a set of specified design methods and the concept of social prototypes were utilized. The article discusses the functioning of these methods. Taking its departure in the concept of ‘fuzzyness’ and ‘the fuzzy front end’ of design projects derived from Elizabeth Sanders and Pieter Jan Stappers the...... authors argue that the main function of the methods was not to present an accurate picture of the design process but to work as tools for managing ‘fuzzyness’, which in social innovation projects is not confined to the front end of the process but establishes itself as a general condition. Thus the...

  16. Fuel related risks; Braenslerisker

    Energy Technology Data Exchange (ETDEWEB)

    Englund, Jessica; Sernhed, Kerstin; Nystroem, Olle; Graveus, Frank (Grontmij AB, (Sweden))

    2012-02-15

    The project, within which this work report was prepared, aimed to complement the Vaermeforsk publication 'Handbook of fuels' on fuel related risks and measures to reduce the risks. The fuels examined in this project where the fuels included in the first version of the handbook from 2005 plus four additional fuels that will be included in the second and next edition of the handbook. Following fuels were included: woodfuels (sawdust, wood chips, powder, briquettes), slash, recycled wood, salix, bark, hardwood, stumps, straw, reed canary grass, hemp, cereal, cereal waste, olive waste, cocoa beans, citrus waste, shea, sludge, forest industrial sludge, manure, Paper Wood Plastic, tyre, leather waste, cardboard rejects, meat and bone meal, liquid animal and vegetable wastes, tall oil pitch, peat, residues from food industry, biomal (including slaughterhouse waste) and lignin. The report includes two main chapters; a general risk chapter and a chapter of fuel specific risks. The first one deals with the general concept of risk, it highlights laws and rules relevant for risk management and it discuss general risks that are related to the different steps of fuel handling, i.e. unloading, storing, processing the fuel, transportation within the facility, combustion and handling of ashes. The information that was used to produce this chapter was gathered through a literature review, site visits, and the project group's experience from risk management. The other main chapter deals with fuel-specific risks and the measures to reduce the risks for the steps of unloading, storing, processing the fuel, internal transportation, combustion and handling of the ashes. Risks and measures were considered for all the biofuels included in the second version in the handbook of fuels. Information about the risks and risk management was gathered through interviews with people working with different kinds of fuels in electricity and heat plants in Sweden. The information from

  17. Small Mercury Relativity Orbiter

    Science.gov (United States)

    Bender, Peter L.; Vincent, Mark A.

    1989-01-01

    The accuracy of solar system tests of gravitational theory could be very much improved by range and Doppler measurements to a Small Mercury Relativity Orbiter. A nearly circular orbit at roughly 2400 km altitude is assumed in order to minimize problems with orbit determination and thermal radiation from the surface. The spacecraft is spin-stabilized and has a 30 cm diameter de-spun antenna. With K-band and X-band ranging systems using a 50 MHz offset sidetone at K-band, a range accuracy of 3 cm appears to be realistically achievable. The estimated spacecraft mass is 50 kg. A consider-covariance analysis was performed to determine how well the Earth-Mercury distance as a function of time could be determined with such a Relativity Orbiter. The minimum data set is assumed to be 40 independent 8-hour arcs of tracking data at selected times during a two year period. The gravity field of Mercury up through degree and order 10 is solved for, along with the initial conditions for each arc and the Earth-Mercury distance at the center of each arc. The considered parameters include the gravity field parameters of degree 11 and 12 plus the tracking station coordinates, the tropospheric delay, and two parameters in a crude radiation pressure model. The conclusion is that the Earth-Mercury distance can be determined to 6 cm accuracy or better. From a modified worst-case analysis, this would lead to roughly 2 orders of magnitude improvement in the knowledge of the precession of perihelion, the relativistic time delay, and the possible change in the gravitational constant with time.

  18. Alcohol-Related Liver Disease

    Science.gov (United States)

    ... to run events. Please support us. Donate | Volunteer Alcohol-Related Liver Disease Discussion on Inspire Support Community ... Liver > Liver Disease Information > Alcohol-Related Liver Disease Alcohol-Related Liver Disease Explore this section to learn ...

  19. [Sleep related eating disorder].

    Science.gov (United States)

    Inoue, Yuichi; Komada, Yoko

    2010-01-01

    Nighttime eating is categorized as either sleep-related eating disorder (SRED) or night eating syndrome (NES). Critical reviews of the literature on both disorders have suggested that they are situated at opposite poles of a disordered eating spectrum. The feeding behavior in SRED is characterized by recurrent episodes of eating after an arousal from nighttime sleep with amnesia. Conversely, NES could be considered as an abnormality in the circadian rhythm of meal timing with a normal circadian timing of sleep onset. Both conditions clearly concentrate to occur during young adulthood, and are often relentless and chronic. Misunderstanding and low awareness of SRED and NES have limited our ability to determine the exact prevalence of the two disorders. SRED is frequently associated with other sleep disorders, in particular parasomnias such as sleep walking. Cognitive-behavioral therapy is ineffective, but pharmacotherapy is very effective in controlling SRED. Especially, studies have shown that the anti-seizure medication topiramate may be an effective treatment for SRED. PMID:21077298

  20. Magnetoplumbite-related oxides

    International Nuclear Information System (INIS)

    These ferrites were prepared from Fe2O3, MO oxides (M = Ba,Sr,Pb) and MeO oxides (Me = Mg,Mn,Co,Zn). Chemical compositions of the main barium ferrites (M = Ba) are represented in a ternary diagram. The structures of these various compounds (M,Y,W,Z,X,U) are closely related. The simplest one is the compound BaFe12O19 (M). Its crystal structure is similar to that of the mineral magnetoplumbite PbFe7.5Mn3.5Al0.5O19 (PbM12O19) (5). For this reason the hexagonal ferrites are also known as magnetoplumbite-type ferrites (called MP-type in this paper). When the Fe3+ ions are replaced by other trivalent ions, such as Al3+, Ga3+, another group of MP-type oxides, namely AB12O19 (A = Ba2+ or a large divalent ion; B = Al3+ or Ga3+) is obtained. In this paper, the authors briefly review ideal structure and major properties and uses, especially in the case of ferrites

  1. AIDS-related myopathy.

    Science.gov (United States)

    Sheikh, Rafiq A.; Yasmeen, Shagufta; Munn, Robert; Ruebner, Boris H.; Ellis, William G.

    1999-09-01

    Infection with the human immunodeficiency virus (HIV) is often associated with the acquired immunodeficiency syndrome (AIDS), and wasting is one of the defining clinical features of AIDS. Muscular weakness due to myopathy may develop at any stage of HIV infection. We report two illustrative cases of HIV-associated myopathies. One was due to inflammatory myosits most likely directly related to the HIV infection, and the other was most likely the result of mitochondrial damage due to zidovudine, a nucleoside analogue commonly used in treating HIV infection. Biopsies from both patients showed alterations of myofiber structures, of varying severity, culminating in necrosis, lipid droplets, and lymphoplasmocytic inflammatory response. The zidovudine-treated patient also showed distinctive mitochondrial changes, predominantly enlargement, variation in shape and size, and disorganization of the cristae. These two types of HIV-associated inflammatory myopathies are reviewed, along with other HIV-associated myopathies, including HIV wasting syndrome, nemaline rod myopathy, pyomyositis, rhabdomyolysis, cardiomyopathy, and other miscellaneous myopathies associated with HIV infection. PMID:11810429

  2. [Chronotherapy and relativity theory].

    Science.gov (United States)

    Polishchuk, N A

    2008-01-01

    The course of time itself in alive organisms is treated from positions of the special theory of the relativity created by A. Einstein in 1905 and added by the Nobel winners H.A.Lorentsem, M. Plankom, M. fon Laue. These achievements of fundamental physics have been put in a basis of special medical technology "Resonant chronophytotherapy" (SMT RCPT) which is applied in practice of treatment of chronic diseases for 27 years. Grass tinctures in various dosages are used in SMT RCPT, which patients take once a day during precisely designated time. Parameters "dosage-time" daily vary. SMT RCPT have been conducted in treatment of epilepsy bronchial asthma, rheumatism, sclerodermia, hypertension, chronic glomerulonephritis, vegeto-vascular dystonia, female sterility, circular alopecia, vitiligo, eczema, psoriasis, onychomycosis. SMT RCPT does have adverse events, has no contra-indications to its use, directed, first of all, on elimination of nonspecific signs of a disease, reduces dependence and complications of the use of chemical synthetic preparations. SMT RCPT can be combined with any kind of specific treatment. Internet-variant of SMT RCPT has been developed. Chronomedicine is priority tendency in industrialized countries of the world--the USA, the Great Britain, Germany, France, Russia, China, Japan and appears on lead positions among alternative methods of treatment, both traditional, and non-traditional. PMID:19145832

  3. ERCP Related Sepsis

    Directory of Open Access Journals (Sweden)

    Iffet Palabıyıkoglu

    2005-01-01

    Full Text Available Endoscopic procedures performed worldwide have increased considerably in recent years. In addition to diagnosis, many cases previously necessitating surgery now often can be carried out by endoscopic techniques. However, endoscopy has introduced its own infection risk. Most reports of gastrointestinal endoscopy-associated infection describe sepsis after endoscopic retrograde cholangiopancreatography (ERCP in patients with biliary tract obstruction. During this study, which was conducted by Infection Control Committee of Ankara University Hospital, 13 out of 1147 (1.1% and 17 out of 922 patients (1.8% had ERCP related sepsis in 2002 and 2003 respectively, at the ERCP Unit of Gastroenterology Department. Sepsis-caused mortality were 23.1 and 29.4% in 2002 and 2003 respectively. The first four causative agents were Escherichia coli, Pseudomonas spp, Klebsiella spp and Enterobacter spp. Type and frequency of the causative agents remind that both endogenous and exogenous mechanisms are together responsible for the infections emerging from ERCP Unit. Besides, increasing isolation of Pseudomonas spp. brings out the strong need for re-evaluation of infection control measures, mainly effective cleansing and disinfection of endoscopes.

  4. Superconcentration and related topics

    CERN Document Server

    Chatterjee, Sourav

    2014-01-01

    A certain curious feature of random objects, introduced by the author as “super concentration,” and two related topics, “chaos” and “multiple valleys,” are highlighted in this book. Although super concentration has established itself as a recognized feature in a number of areas of probability theory in the last twenty years (under a variety of names), the author was the first to discover and explore its connections with chaos and multiple valleys. He achieves a substantial degree of simplification and clarity in the presentation of these findings by using the spectral approach. Understanding the fluctuations of random objects is one of the major goals of probability theory and a whole subfield of probability and analysis, called concentration of measure, is devoted to understanding these fluctuations. This subfield offers a range of tools for computing upper bounds on the orders of fluctuations of very complicated random variables. Usually, concentration of measure is useful when more direct prob...

  5. Health related environmental monitoring

    International Nuclear Information System (INIS)

    Radioactive elements and penetrating radiations have been present in earth's environment since the beginning of the solar system and hence the life forms on earth have always been subjected to ionising radiations. These natural radiations comprise the cosmic rays which originate in outer space and those from the radioactive materials normally present in soil, air, water, food and the body. To this natural radiation man had added artificial sources of radiations. These man-made sources are from the nuclear fuel cycle operations that are essential for a nuclear power programme, from the industrial uses of radiation, from defence related activities and from the medical uses of radiation. Natural background radiation is the major contributors to radiation exposures received by mankind and these exposures have remained fairly constant over several thousand years. Enhanced natural radiation levels due to man's activities have been identified, like for example in some mining areas. Fly ash from thermal power plants contain natural radioactive elements and the dispersal of this fly ash can result in enhanced natural radiation exposures. There are also other such sources like phosphatic fertilizer and supersonic travel. United Nations Scientific Committee on the Effects of Atomic Radiations (UNSCEAR) has periodically reviewed the current information on this subject

  6. Stakeholder Relations Office

    CERN Multimedia

    2013-01-01

    Scientists, politicians, the public, school children, our neighbours, you. All of these groups of people have a stake in CERN, and all are important to us.   The list of stakeholders in an organisation as large and complex as CERN is a long and ever lengthening one. Each group has its own specific interests and needs in terms of what kind of information it requires from CERN and how we should engage. It’s important, therefore, for us to ensure that we’re communicating optimally with everyone we care about and who cares about us. This is something that CERN has always taken seriously. The CERN Courier, for example, was first published in 1959 and we had a pro-active public information office right from the start. Today, our stakeholder relations are spread between several groups and teams, reflecting the nature of CERN today. But while we’re already doing a good job, I think we can do better by exploiting the synergies between these teams, and that’s wh...

  7. Vývoj public relations

    OpenAIRE

    Moravec, Petr

    2013-01-01

    Work is aimed at the topic of Public Relations Development. It deals with the issue of the historical development of public relations. The theoretical part is based on studying theoretical knowledge of public relations, determining the appropriate definition, setting the tools to promote public relations, division to types of public relations according to various aspects, defining the subject or target group of public relations and describing the practice of PR agents. The practical chapter i...

  8. Complex aggregates in relational learning

    OpenAIRE

    Vens, Celine

    2007-01-01

    In relational learning one learns patterns from relational databases, which usually contain multiple tables that are interconnected via relations. These relations may be of one-to-many or many-to-many cardinality ratios. Thus, an example for which a prediction is to be given may be related to a set of objects that are possibly relevant for that prediction. Relational classifiers differ with respect to how they handle these sets: some use properties of the set as a whole (...

  9. Shaping Relations: Exploiting Relational Features for Visuospatial Priming

    Science.gov (United States)

    Livins, Katherine A.; Doumas, Leonidas A. A.; Spivey, Michael J.

    2016-01-01

    Although relational reasoning has been described as a process at the heart of human cognition, the exact character of relational representations remains an open debate. Symbolic-connectionist models of relational cognition suggest that relations are structured representations, but that they are ultimately grounded in feature sets; thus, they…

  10. A Discussion of Special Relativity

    OpenAIRE

    Weinstein, Galina

    2012-01-01

    Five topics: A rigid body does not exist in the special theory of relativity; distant simultaneity defined with respect to a given frame of reference without any reference to synchronized clocks; challenges on Einstein's connection of synchronization and contraction; a theory of relativity without light, composition of relative velocities and space of relative velocities.

  11. Relationalism or why diplomats find international relations theory strange

    DEFF Research Database (Denmark)

    Adler-Nissen, Rebecca

    2015-01-01

    In this conclusion, which reflects critically on the relational approach to diplomacy and its wider consequences, I argue that diplomats are estranged from IR theory and vice versa - because International Relations scholars generally subscribe to substantialism, whereas diplomats tend to think...... in terms of relations. In fact, a deeper understanding of these relations is a key theoretical take-away point of this book. More specifically, I argue that relationalism - as a meta-theoretical approach - not only helps us understand the diplomatic production of world politics, relationalism also reflects...... unarticulated sense, that world politics is deeply relational. Their job is to make those relations "work," and they are convinced that important knowledge can be gained by consulting and meeting with foreign powers, that is, "the other." As such, they subscribe to a relational thinking (shared to some extent...

  12. Public Relations Sebagai Tools Marketing

    OpenAIRE

    Mukhriz, Dewi Wulandari

    2015-01-01

    This study, entitled "Public Relations As Marketing Tools In Increasing image in Hotel Inna Dharma Deli". The purpose of this study was to determine the influence of public relations activities as marketing tools to the image at the Hotel Inna Dharma Deli. A correlational study aimed to see how far the variable public relations activities as marketing tools affect the company's image variables. The theories used is communications, public relations, marketing, marketing public relations, an...

  13. Relational Investing and Agency Theory

    OpenAIRE

    Ian Ayres; Peter Cramton

    1994-01-01

    This Article analyzes how, and when, corporate governance could be improved by utilizing "relational investing." The term relational investing is just coming into vogue and there does not yet seem to be a consensus on what it means. Although the term has been trumpeted on the cover of Business Week, before the Conference on Relational Investing at Columbia University, relatively little legal writing had been published on the subject. For the purposes of this Article, we define relational inve...

  14. Three levels of understanding physical relativity: Galileo's relativity, Up-to-date Galileo's relativity and Einstein's relativity: A historical survey

    OpenAIRE

    Rothenstein, Bernhard; Nafornita, Corina

    2004-01-01

    We present a way of teaching Einstein's special relativity. It starts with Galileo's relativity, the learners know from previous lectures. The lecture underlines that we can have three transformation equations for the space-time coordinates of the same event, which lead to absolute clock readings, time intervals and lengths (Galileo's relativity), to absolute clock readings but to relative time intervals and lengths (up-to-date Galileo transformations) and to relative clock readings time inte...

  15. Are hospitals also for relatives?

    DEFF Research Database (Denmark)

    Nissen, Nina Konstantin; Madsen, Mette; Kjøller, Mette;

    2008-01-01

    relatives of patients with cardiac diseases is sparse. This study aimed to survey the prevalence of health services for relatives of cardiac patients in Denmark. METHODS: We surveyed activities offered by Danish hospitals to the relatives of cardiac patients. Data were obtained from an Internet-based survey...... and 50 of 55 invited hospital departments participated. RESULTS: Almost all departments offer activities to relatives of cardiac patients, but only one-quarter have activities specifically aimed at supporting relatives. Large departments offer activities for relatives more often than smaller...... departments. Participation rates for relatives are generally low, and the departments experience numerous barriers in providing activities for relatives of heart patients. CONCLUSIONS: Danish hospitals focus very little on relatives of cardiac patients, and this seems to be due to several factors, including...

  16. Genesis of general relativity - Discovery of general relativity

    OpenAIRE

    Weinstein, Galina

    2012-01-01

    The intermediate stage of the development of general relativity is inseparable of Marcel Grossmann's mathematical assistance. Einstein acknowledges Grossmann's help during 1912-1914 to the development of general relativity. In fact, as with special relativity so was it with General relativity, Einstein received assistance only from his old friends, Marcel Grossmann and Michele Besso. However, he continued to consider Besso as his eternal "sounding board"...

  17. Operational indistinguishabilty of doubly special relativities from special relativity

    OpenAIRE

    Ahluwalia-Khalilova, D. V.

    2002-01-01

    We argue that existing doubly special relativities may not be operationally distinguishable from the special relativity. In the process we point out that some of the phenomenologically motivated modifications of dispersion relations, and arrived conclusions, must be reconsidered. Finally, we reflect on the possible conceptual issues that arise in quest for a theory of spacetime with two invariant scales.

  18. On the relation between mathematical and numerical relativity

    OpenAIRE

    Andersson, L.

    2006-01-01

    The large scale binary black hole effort in numerical relativity has led to an increasing distinction between numerical and mathematical relativity. This note discusses this situation and gives some examples of succesful interactions between numerical and mathematical methods is general relativity.

  19. Chiral squaring and KLT relations

    CERN Document Server

    Schreiber, Anders

    2016-01-01

    We demonstrate that amplitudes based on matter supermultiplets can be combined to provide amplitudes of vector supermultiplets by means of KLT relations. In practice we do this by developing a procedure for removing supersymmetry supercharges from super Yang-Mills theory and supergravity supermultiplets, reducing them to vector and chiral supermultiplets respectively. This way, we reduce the super KLT relations to chiral KLT relations making chiral squaring of amplitudes manifest. We study these chiral KLT relations, discussing permutation symmetry and vanishing relations. Finally some explicit calculations are done to show how the relations work in detail.

  20. European Union-Chinese Relations

    Directory of Open Access Journals (Sweden)

    Víctor Pou Serradell

    2003-09-01

    Full Text Available The present paper situates the relations between the European Union (EU and China in a double framework: the general framework of UE-Asian relations, on the one hand, and the ASEM (Asia-Europe Meeting process initiated in 1996, on the other hand. Likewise, it examines EU-Chinese relations in a specific way –including the relations of the most relevant member states of the EU with China–, the latest events that have occurred in EU-Chinese relations in the new international scenario following the 2001 terrorist attacks in the United States, and the future perspectives for EU-Chinese relations.

  1. Recreation-Related Head Injuries

    Science.gov (United States)

    Recreation-Related Head Injuries American Association of Neurological Surgeons 5550 Meadowbrook Drive, Rolling Meadows, IL 60008-3852  ... and follow instructions on product packaging. Top 15 Recreation/Leisure-Related Head Injuries by Product Product Category ...

  2. Deep MUSE observations in the HDFS. Morpho-kinematics of distant star-forming galaxies down to 108M⊙

    Science.gov (United States)

    Contini, T.; Epinat, B.; Bouché, N.; Brinchmann, J.; Boogaard, L. A.; Ventou, E.; Bacon, R.; Richard, J.; Weilbacher, P. M.; Wisotzki, L.; Krajnović, D.; Vielfaure, J.-B.; Emsellem, E.; Finley, H.; Inami, H.; Schaye, J.; Swinbank, M.; Guérou, A.; Martinsson, T.; Michel-Dansac, L.; Schroetter, I.; Shirazi, M.; Soucail, G.

    2016-06-01

    that the dynamical state of the ionized gas and the level of gravitational interactions of star-forming galaxies is not a strong function of their stellar mass. In the high-mass regime, the MUSE-HDFS galaxies follow the Tully-Fisher relation defined from previous IFS surveys in a similar redshift range. This scaling relation also extends to lower masses/velocities but with a higher dispersion. We find that 90% of the MUSE-HDFS galaxies with stellar masses below 109.5M⊙ have settled gas disks. The MUSE-HDFS galaxies follow the scaling relations defined in the local Universe between the specific angular momentum and stellar mass. However, we find that intermediate-redshift, star-forming galaxies fill a continuum transition from the spiral to elliptical local scaling relations, according to the dynamical state (i.e., rotation- or dispersion-dominated) of the gas. This indicates that some galaxies may lose their angular momentum and become dispersion-dominated prior to becoming passive. Based on observations made with ESO/VLT telescopes at the Paranal Observatory under program ID 60.A-9100(C). Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555.

  3. Angular Momentum and Galaxy Formation Revisited

    Science.gov (United States)

    Romanowsky, Aaron J.; Fall, S. Michael

    2012-12-01

    Motivated by a new wave of kinematical tracers in the outer regions of early-type galaxies (ellipticals and lenticulars), we re-examine the role of angular momentum in galaxies of all types. We present new methods for quantifying the specific angular momentum j, focusing mainly on the more challenging case of early-type galaxies, in order to derive firm empirical relations between stellar j sstarf and mass M sstarf (thus extending earlier work by Fall). We carry out detailed analyses of eight galaxies with kinematical data extending as far out as 10 effective radii, and find that data at two effective radii are generally sufficient to estimate total j sstarf reliably. Our results contravene suggestions that ellipticals could harbor large reservoirs of hidden j sstarf in their outer regions owing to angular momentum transport in major mergers. We then carry out a comprehensive analysis of extended kinematic data from the literature for a sample of ~100 nearby bright galaxies of all types, placing them on a diagram of j sstarf versus M sstarf. The ellipticals and spirals form two parallel j sstarf-M sstarf tracks, with log-slopes of ~0.6, which for the spirals are closely related to the Tully-Fisher relation, but for the ellipticals derives from a remarkable conspiracy between masses, sizes, and rotation velocities. The ellipticals contain less angular momentum on average than spirals of equal mass, with the quantitative disparity depending on the adopted K-band stellar mass-to-light ratios of the galaxies: it is a factor of ~3-4 if mass-to-light ratio variations are neglected for simplicity, and ~7 if they are included. We decompose the spirals into disks and bulges and find that these subcomponents follow j sstarf-M sstarf trends similar to the overall ones for spirals and ellipticals. The lenticulars have an intermediate trend, and we propose that the morphological types of galaxies reflect disk and bulge subcomponents that follow separate, fundamental j sstarf

  4. Deep MUSE observations in the HDFS. Morpho-kinematics of distant star-forming galaxies down to 108M⊙

    Science.gov (United States)

    Contini, T.; Epinat, B.; Bouché, N.; Brinchmann, J.; Boogaard, L. A.; Ventou, E.; Bacon, R.; Richard, J.; Weilbacher, P. M.; Wisotzki, L.; Krajnović, D.; Vielfaure, J.-B.; Emsellem, E.; Finley, H.; Inami, H.; Schaye, J.; Swinbank, M.; Guérou, A.; Martinsson, T.; Michel-Dansac, L.; Schroetter, I.; Shirazi, M.; Soucail, G.

    2016-06-01

    Aims: Whereas the evolution of gas kinematics of massive galaxies is now relatively well established up to redshift z ~ 3, little is known about the kinematics of lower mass (M⋆≤ 1010M⊙) galaxies. We use MUSE, a powerful wide-field, optical integral-field spectrograph (IFS) recently mounted on the VLT, to characterize this galaxy population at intermediate redshift. Methods: We made use of the deepest MUSE observations performed so far on the Hubble Deep Field South (HDFS). This data cube, resulting from 27 h of integration time, covers a one arcmin2 field of view at an unprecedented depth (with a 1σ emission-line surface brightness limit of 1 × 10-19 erg s-1 cm-2 arcsec-2) and a final spatial resolution of ≈0.7''. We identified a sample of 28 resolved emission-line galaxies, extending over an area that is at least twice the seeing disk, spread over a redshift interval of 0.2 MUSE data and model the disk (both in 2D and in 3D with GalPaK3D) to retrieve their intrinsic gas kinematics, including the maximum rotation velocity and velocity dispersion. Results: We build a sample of resolved emission-line galaxies of much lower stellar mass and SFR (by ~1 - 2 orders of magnitude) than previous IFS surveys. The gas kinematics of most of the spatially resolved MUSE-HDFS galaxies is consistent with disk-like rotation, but about 20% have velocity dispersions that are larger than the rotation velocities and 30% are part of a close pair and/or show clear signs of recent gravitational interactions. These fractions are similar to what has been found in previous IFS surveys of more massive galaxies, indicating that the dynamical state of the ionized gas and the level of gravitational interactions of star-forming galaxies is not a strong function of their stellar mass. In the high-mass regime, the MUSE-HDFS galaxies follow the Tully-Fisher relation defined from previous IFS surveys in a similar redshift range. This scaling relation also extends to lower masses

  5. Relative Information Loss - An Introduction

    CERN Document Server

    Geiger, Bernhard C

    2012-01-01

    We introduce a relative variant of information loss to characterize the behavior of deterministic input-output systems. We show that the relative loss is closely related to Renyi's information dimension. We provide an upper bound for continuous input random variables and an exact result for a class of functions (comprising quantizers) with infinite absolute information loss. A connection between relative information loss and reconstruction error is investigated.

  6. Team incentives in relational contracts

    OpenAIRE

    Kvaløy, Ola

    2003-01-01

    Incentive schemes for teams are compared. I ask: under which conditions are relational incentive contracts based on joint performance evaluation, relative performance evaluation and independent performance evaluation self-enforceable. The framework of Che and Yoo (2001) on team incentives is combined with the framework of Baker, Gibbons and Murphy (2002) on relational contracts. In a repeated game between one principal and two agents, I find that incentives based on relative or independent pe...

  7. Relative Pay and Labor Supply

    OpenAIRE

    Anat Bracha; Uri Gneezy; George Loewenstein

    2015-01-01

    We examine the impact of relative wages on labor supply in a laboratory experiment. We test the hypothesis that, ceteris paribus, making a given wage high (low) relative to other wage levels will lead to an increase (decrease) in labor supply. We find that labor supply does respond significantly to relative pay, and in the expected direction. However, when a strong enough reason for the relative low pay is given, this difference disappears.

  8. Public relations: contributions from Ljubljana:

    OpenAIRE

    Verčič, Dejan

    2011-01-01

    Public relations emerged as an academic discipline in the 1980s in the US, and in 1990s it institutionalised itself in European academia as well. Work at the Marketing Communication and Public Relations department, Faculty of Social Sciences, University of Ljubljana, has been instrumental in the Europeanisation and globalisation of the predominantly US public relations theory and contributed to the development of the reflective model of public relations. Odnosi z javnostmi so se kot akadem...

  9. RELATIVE POTENCY RANKING FOR CHLOROPHENOLS

    Science.gov (United States)

    Recently the National Center for Environmental Assessment-Cincinnati completed a feasibility study for developing a toxicity related relative potency ranking scheme for chlorophenols. In this study it was concluded that a large data base exists pertaining to the relative toxicity...

  10. Education for Corporate Public Relations.

    Science.gov (United States)

    Baxter, Bill L.

    1985-01-01

    Surveyed members of the Public Relations Society of America who reported that (1) students planning public relations careers in corporations should take courses in this order of priority: journalism, public relations, internships, speech communication, marketing, etc., and (2) an MBA degree was the best advanced education degree. (PD)

  11. A Relational Theory of Working

    Science.gov (United States)

    Blustein, David L.

    2011-01-01

    Building on diverse influences from critical perspectives in vocational psychology and the relational movement in contemporary psychological discourse, this article introduces the relational theory of working. Attending to the full array of people who work and who want to work, the relational theory conceptualizes working as an inherently…

  12. On Controversies in Relativity Theory

    OpenAIRE

    Vankov, Anatoli Andrei

    2006-01-01

    Controversies arise when specialists disagree on some particular issue. This normally occurs in any scientific brunch. We analyze some controversies, which have a good cause in Special Relativity. The paper does not question Special Relativity Theory but it challenges changing deeply held academic beliefs about imaginary experiments in Special Relativity Theory. PACS 03.30.+p

  13. Introducing Relativity into Quantum Chemistry

    Science.gov (United States)

    Li, Wai-Kee; Blinder, S. M.

    2011-01-01

    It is not often realized by chemists that the special theory of relativity is behind several aspects of quantum chemistry. The Schrdinger equation itself is based on relations between space-time and energy-momentum four vectors. Electron spin is, of course, the most obvious manifestation of relativity. The chemistry of some heavy elements is…

  14. Sino-U. S. Relations

    Institute of Scientific and Technical Information of China (English)

    Fu Mengzi; Cai Jinghong; Yue Xing

    2007-01-01

    @@ A New View on Sino-U. S.Relations Sino-U. S. relations seem to have emerged into a more positive light in recent years. China and the United States have sustained a strong relationship since 9/11, for the simple reason that international relations at present require mutual support.

  15. Relations in a quantized elastica

    International Nuclear Information System (INIS)

    In the previous article (Matsutani S 2002 J. Geom. Phys. 43 146-62), we showed the hyperelliptic solutions of a loop soliton as a study of a quantized elastica. Using the results, this paper studies relations between the quantized elastica and integrals of its Schwarz derivative, the winding effects in the quantized elastica problems and some other related relations

  16. Note on New KLT relations

    CERN Document Server

    Feng, Bo; Huang, Rijun; Jia, Yin

    2010-01-01

    In this short note, we present two results about KLT relations discussed in recent several papers. Our first result is the re-derivation of Mason-Skinner MHV amplitude by applying the S_{n-3} permutation symmetric KLT relations directly to MHV amplitude. Our second result is the equivalence proof of the newly discovered S_{n-2} permutation symmetric KLT relations and the well-known S_{n-3} permutation symmetric KLT relations. Although both formulas have been shown to be correct by BCFW recursion relations, our result is the first direct check using the regularized definition of the new formula.

  17. Note on new KLT relations

    Science.gov (United States)

    Feng, Bo; He, Song; Huang, Rijun; Jia, Yin

    2010-10-01

    In this short note, we present two results about KLT relations discussed in recent several papers. Our first result is the re-derivation of Mason-Skinner MHV amplitude by applying the S n-3 permutation symmetric KLT relations directly to MHV amplitude. Our second result is the equivalence proof of the newly discovered S n-2 permutation symmetric KLT relations and the well-known S n-3 permutation symmetric KLT relations. Although both formulas have been shown to be correct by BCFW recursion relations, our result is the first direct check using the regularized definition of the new formula.

  18. Relative eye size in elasmobranchs.

    Science.gov (United States)

    Lisney, Thomas J; Collin, Shaun P

    2007-01-01

    Variation in relative eye size was investigated in a sample of 46 species of elasmobranch, 32 species of sharks and 14 species of batoids (skates and rays). To get a measure of eye size relative to body size, eye axial diameter was scaled with body mass using least-squares linear regression, using both raw species data, where species are treated as independent data points, and phylogenetically independent contrasts. Residual values calculated for each species, using the regression equations describing these scaling relationships, were then used as a measure of relative eye size. Relative and absolute eye size varies considerably in elasmobranchs, although sharks have significantly relatively larger eyes than batoids. The sharks with the relatively largest eyes are oceanic species; either pelagic sharks that move between the epipelagic (0-200 m) and 'upper' mesopelagic (200-600 m) zones, or benthic and benthopelagic species that live in the mesopelagic (200-1,000 m) and, to a lesser extent, bathypelagic (1,000-4,000 m) zones. The elasmobranchs with the relatively smallest eyes tend to be coastal, often benthic, batoids and sharks. Active benthopelagic and pelagic species, which prey on active, mobile prey also have relatively larger eyes than more sluggish, benthic elasmobranchs that feed on more sedentary prey such as benthic invertebrates. A significant positive correlation was found between absolute eye size and relative eye size, but some very large sharks, such as Carcharodon carcharias have absolutely large eyes, but have relatively small eyes in relation to body mass. PMID:17314474

  19. Towards a relational health promotion.

    Science.gov (United States)

    Veenstra, Gerry; Burnett, Patrick John

    2016-03-01

    The Ottawa Charter for Health Promotion exhibits a substantialist approach to the agency-structure dichotomy. From a substantialist point of view, both individual agency and social structure come preformed and subsequently relate to and influence one another, starkly positioning the choices made by individuals against the structured sets of opportunities and constraints in reference to which choices are made. From a relational perspective, however, relations between elements, not the elements themselves, are the primary ontological focus. We advocate for a relational approach to the structure-agency dichotomy, one that locates both agency and structure in social relations and thereby dissolves the stark distinction between them, suggesting that relational theories can provide useful insights into how and why people 'choose' to engage in health-related behaviours. Pierre Bourdieu's theory of practice, predicated upon the notions of field, capital and habitus, is exemplary in this regard. PMID:25080467

  20. Behavior Relativity of Petri Nets

    Institute of Scientific and Technical Information of China (English)

    蒋昌俊; 王怀清; 廖少毅

    2002-01-01

    This paper presents a novel methodology for modelling and analyzing of behav-ior relations of concurrent systems. The set of all firing sequences of a Petri net is an importanttool for describing the dynamic behavior of concurrent systems. In this paper, the behaviorrelativity of two concurrent subsystems in their synchronous composition is presented. Such be-havior relativities, including Controlled Relativity, United Relativity, Interactive Relativity andExclusive Relativity, are defined respectively. The properties of the relativities are discussed indetail. The analysis method for these properties is based on minimum T-invariants, when twosubsystems are live bounded Petri nets. A well-known example has also been analyaed usingthe new methodology to demonstrate the advantages of the proposed methodology.

  1. Doubly Special Relativity: A New Relativity or Not?

    OpenAIRE

    Jafari, Nosratollah; Shariati, Ahmad

    2006-01-01

    Double Special Relativity theories are the relativistic theories in which the transformations between inertial observers are characterized by two observer-independent scales of the light speed and the Planck length. We study two main examples of these theories and want to show that these theories are not the new theories of relativity, but only are re-descriptions of Einstein's special relativity in the non-conventional coordinates.

  2. Relational persons and relational processes: developing the notion of relationality for the sociology of personal life

    OpenAIRE

    Roseneil, Sasha; Ketokivi, K.

    2014-01-01

    The concept of relationality has recently found widespread favour in British sociology, particularly in the emergent sub-field of the sociology of personal life, which is characterised by its attachment to the concept. However, this ‘relational turn’ is under-theorized and pays little attention to the substantial history of relational thinking across the human sciences. This paper argues that the notion of relationality in the sociology of personal life might be strengthened by an exploration...

  3. Shaping relations: Exploiting relational features for visuospatial priming.

    Science.gov (United States)

    Livins, Katherine A; Doumas, Leonidas A A; Spivey, Michael J

    2016-01-01

    Although relational reasoning has been described as a process at the heart of human cognition, the exact character of relational representations remains an open debate. Symbolic-connectionist models of relational cognition suggest that relations are structured representations, but that they are ultimately grounded in feature sets; thus, they predict that activating those features can affect the trajectory of the relational reasoning process. The present work points out that such models do not necessarily specify what those features are though, and endeavors to show that spatial information is likely a part of it. To this end, it presents 2 experiments that used visuospatial priming to affect the course of relational reasoning. The first is a relational category-learning experiment in which this type of priming was shown to affect which spatial relation was learned when multiple were possible. The second used crossmapping analogy problems, paired with this same type of priming, to show that visuospatial cues can make participants more likely to map analogs based on relational roles, even with short presentation times. (PsycINFO Database Record PMID:26322829

  4. The special theory of relativity bound with relativity

    CERN Document Server

    Dingle, Herbert

    2014-01-01

    The Special Theory of Relativity:Based on a short course of lectures delivered in the late 1930s, this short book presents the theory of Special Relativity by formulating a redefinition of the measurement of length, and thus will appeal to students of physics who wish to think through Einstein's thought without the encumbrance of quasi-scientific concepts and language. Relativity: A Very Elementary Exposition:This brief lecture, delivered in October 1921 and published for the first time in 1925, offers an explanation of Einstein's theory of Special Relativity for the non-scientist, giving a ge

  5. Relating Derived Relations as a Model of Analogical Reasoning: Reaction Times and Event-Related Potentials

    OpenAIRE

    Barnes-Holmes, Dermot; Regan, Donal; Barnes-Holmes, Yvonne; Commins, Sean; Walsh, Derek; Stewart, Ian; Smeets, Paul M; Whelan, Robert; Dymond, Simon

    2005-01-01

    The current study aimed to test a Relational Frame Theory (RFT) model of analogical reasoning based on the relating of derived same and derived difference relations. Experiment 1 recorded reaction time measures of similar–similar (e.g., “apple is to orange as dog is to cat”) versus different–different (e.g., “he is to his brother as chalk is to cheese”) derived relational responding, in both speed-contingent and speed-noncontingent conditions. Experiment 2 examined the event-related potential...

  6. Special Relativity in Week One: 1) The Principle of Relativity

    Science.gov (United States)

    Huggins, Elisha

    2011-01-01

    We like to begin an introductory physics course with a law of physics that applies to everything, has no known exceptions, and whose consequences are already familiar to students. That law is the principle of relativity. By focusing on the principle of relativity itself, and a careful selection of the thought experiments, we can comfortably…

  7. How public relations works: theoretical roots and public relations perspectives

    NARCIS (Netherlands)

    Ø. Ihlen; B. van Ruler

    2007-01-01

    Public relations is often studied from a managerial, instrumental perspective or a psychological, behavioral perspective. To understand the role of public relations in building trust or mistrust and to develop - or destroy - a license to operate, it needs also to be studied as a social phenomenon. T

  8. The Principle of Relativity and Special Relativity Triple

    OpenAIRE

    Guo, Han-Ying; Wu, Hong-Tu; Zhou, Bin

    2008-01-01

    Based on the principle of relativity and the postulate on universal invariant constants ($c,l$) as well as Einstein's isotropy conditions, three kinds of special relativity form a triple with a common Lorentz group as isotropy group under full Umov-Weyl-Fock-Lorentz transformations among inertial motions.

  9. Group Relations at Work. Solidarity, Conflict, and Relations with Management.

    Science.gov (United States)

    Hodson, Randy

    1997-01-01

    Coded data from 83 work ethnographies and a telephone survey of 371 workers found that coworker solidarity generates high job satisfaction and better relations with management. Effects of the quality of coworker relationships equaled or exceeded the effects of job characteristics on satisfaction or management relations. (SK)

  10. Two Theories of Special Relativity ?

    CERN Document Server

    Rosinger, Elemer E

    2010-01-01

    Recently, [3], it was shown that Special Relativity is in fact based on one single physical axiom which is that of Reciprocity. Originally, Einstein, [3], established Special Relativity on two physical axioms, namely, the Galilean Relativity and the Constancy of the Speed of Light in inertial reference frames. Soon after, [4,5], it was shown that the Galilean Relativity alone is sufficient for Special Relativity. Here it is important to note that, implicitly, three more assumptions have been used on space-time coordinate transformations, namely, the homogeneity of space-time, the isotropy of space, and a mathematical condition of smoothness type. In [3], a boundedness condition on space-time coordinate transformations is used instead of a usual mathematical smoothness type condition. In this paper it is shown that the respective boundedness condition is closely related to a Principle of Transformation Increment Ratio Limitation, or in short, PTIRL, which has an obvious physical meaning. It is also shown that ...

  11. General relativity basics and beyond

    CERN Document Server

    Date, Ghanashyam

    2015-01-01

    A Broad Perspective on the Theory of General Relativity and Its Observable Implications General Relativity: Basics and Beyond familiarizes students and beginning researchers with the basic features of the theory of general relativity as well as some of its more advanced aspects. Employing the pedagogical style of a textbook, it includes essential ideas and just enough background material needed for readers to appreciate the issues and current research. Basics The first five chapters form the core of an introductory course on general relativity. The author traces Einstein’s arguments and presents examples of space-times corresponding to different types of gravitational fields. He discusses the adaptation of dynamics in a Riemannian geometry framework, the Einstein equation and its elementary properties, and different phenomena predicted or influenced by general relativity. Beyond Moving on to more sophisticated features of general relativity, the book presents the physical requirements of a well-defined de...

  12. Reformulating the Quantum Uncertainty Relation

    Science.gov (United States)

    Li, Jun-Li; Qiao, Cong-Feng

    2015-08-01

    Uncertainty principle is one of the cornerstones of quantum theory. In the literature, there are two types of uncertainty relations, the operator form concerning the variances of physical observables and the entropy form related to entropic quantities. Both these forms are inequalities involving pairwise observables, and are found to be nontrivial to incorporate multiple observables. In this work we introduce a new form of uncertainty relation which may give out complete trade-off relations for variances of observables in pure and mixed quantum systems. Unlike the prevailing uncertainty relations, which are either quantum state dependent or not directly measurable, our bounds for variances of observables are quantum state independent and immune from the “triviality” problem of having zero expectation values. Furthermore, the new uncertainty relation may provide a geometric explanation for the reason why there are limitations on the simultaneous determination of different observables in N-dimensional Hilbert space.

  13. Rhetorical relations for information retrieval

    DEFF Research Database (Denmark)

    Lioma, Christina; Larsen, Birger; Lu, Wei

    2012-01-01

    -called discourse structure has been applied successfully to several natural language processing tasks. This work studies the use of rhetorical relations for Information Retrieval (IR): Is there a correlation between certain rhetorical relations and retrieval performance? Can knowledge about a document’s rhetorical......Typically, every part in most coherent text has some plausible reason for its presence, some function that it performs to the overall semantics of the text. Rhetorical relations, e.g. contrast, cause, explanation, describe how the parts of a text are linked to each other. Knowledge about this so...... relations be useful to IR? We present a language model modification that considers rhetorical relations when estimating the relevance of a document to a query. Empirical evaluation of different versions of our model on TREC settings shows that certain rhetorical relations can benefit retrieval effectiveness...

  14. Foundations of Relational Particle Dynamics

    OpenAIRE

    Anderson, Edward

    2007-01-01

    Relational particle dynamics include the dynamics of pure shape and cases in which absolute scale or absolute rotation are additionally meaningful. These are interesting as regards the absolute versus relative motion debate as well as discussion of conceptual issues connected with the problem of time in quantum gravity. In spatial dimension 1 and 2 the relative configuration spaces of shapes are n-spheres and complex projective spaces, from which knowledge I construct natural mechanics on the...

  15. A RELATION BETWEEN WEB PAGES

    OpenAIRE

    DORU ANASTASIU POPESCU

    2011-01-01

    In this paper we define a relation on the set of web pages from a web application. With the help of this relation, we obtain a partition of this set into subsets. Verifying and testing the web application will be accomplished by testing only one representative in each subset. We present two algorithms, one for verifying the relation between two web pages and one for determining which pages to test.

  16. Chiral squaring and KLT relations

    OpenAIRE

    Schreiber, Anders

    2016-01-01

    We demonstrate that amplitudes based on matter supermultiplets can be combined to provide amplitudes of vector supermultiplets by means of KLT relations. In practice we do this by developing a procedure for removing supersymmetry supercharges from super Yang-Mills theory and supergravity supermultiplets, reducing them to vector and chiral supermultiplets respectively. This way, we reduce the super KLT relations to chiral KLT relations making chiral squaring of amplitudes manifest. We study th...

  17. Imitative obesity and relative utility.

    OpenAIRE

    Blanchflower, David G.; Oswald, Andrew J.; Van Landeghem, Bert

    2009-01-01

    If human beings care about their relative weight, a form of imitative obesity can emerge (in which people subconsciously keep up with the weight of the Joneses). Using Eurobarometer data on 29 countries, this paper provides cross-sectional evidence that overweight perceptions and dieting are influenced by a person's relative BMI, and longitudinal evidence from the German Socioeconomic Panel that well-being is influenced by relative BMI. Highly educated people see themselves as fatter -- at an...

  18. Armenian Theory of Special Relativity

    OpenAIRE

    Nazaryan, Robert; Nazaryan, Haik

    2013-01-01

    By using the principle of relativity (first postulate), together with new defined nature of the universal speed (our second postulate) and homogeneity of time-space (our third postulate), we derive the most general transformation equations of relativity in one dimensional space. According to our new second postulate, the universal (not limited) speed c in Armenian Theory of Special Relativity is not the actual speed of light but it is the speed of time which is the same in all inertial system...

  19. Crystal Microbalance Monitors Relative Humidity

    Science.gov (United States)

    Yang, L. C.

    1984-01-01

    Sensor monitors water evaporation in industrial drying processes. Measured adsorption isotherm for instrument essentially linear over entire range of relative humidity. Testing at each temperature setting less than half hour for full relative-humidity range, with estimated frequency response time less than 10 seconds. Used to measure relative humidity of ambient atmosphere near drying paper, food textile fabrics and pulp to optimize water-drying portion of processing cycle.

  20. Some Paradoxes in Special Relativity

    OpenAIRE

    Gu, Ying-Qiu

    2009-01-01

    The special theory of relativity is the foundation of modern physics, but its unusual postulate of invariant vacuum speed of light results in a number of plausible paradoxes. This situation leads to radical criticisms and suspicions against the theory of relativity. In this paper, from the perspective that the relativity is nothing but a geometry, we give a uniform resolution to some famous and typical paradoxes such as the ladder paradox, the Ehrenfest's rotational disc paradox. The discussi...

  1. Relational link-based ranking

    OpenAIRE

    Geerts, Floris; Mannila, Heikki; Terzi, Evimaria

    2004-01-01

    Link analysis methods show that the interconnections between web pages have lots of valuable information. The link analysis methods are, however, inherently oriented towards analyzing binary relations. We consider the question of generalizing link analysis methods for analyzing relational databases. To this aim, we provide a generalized ranking framework and address its practical implications. More specifically, we associate with each relational database and set of queries a unique weig...

  2. LABOUR RELATIONS IN POSTINDUSTRIAL ECONOMY

    OpenAIRE

    Yuriy Rostislavovitch Chistyakov; Natalia Nikolaevna Rasumovskaya

    2013-01-01

    The article deals with inadequacy of present-day labour relations in economy. Out of date form of labour relations makes workforce dependable, causes social inequality, prevents economical development. The article gives results of theoretical and empiric research. The mechanism of guaranteed reproduction of labour to be realized as social partnership is offered.Purpose: the purpose is to give critical estimation of present-day labour relations in postindustrial economy.Method of studies: mono...

  3. Origin of conical dispersion relations

    OpenAIRE

    Hojman, Sergio A.

    2013-01-01

    A mechanism that produces conical dispersion relations is presented. A Kronig Penney one dimensional array with two different strengths delta function potentials gives rise to both the gap closure and the dispersion relation observed in graphene and other materials. The Schr\\''odinger eigenvalue problem is locally invariant under the infinite dimensional Virasoro algebra near conical dispersion points in reciprocal space, thus suggesting a possible relation to string theory.

  4. Relational Parametricity for Computational Effects

    CERN Document Server

    Møgelberg, Rasmus Ejlers

    2009-01-01

    According to Strachey, a polymorphic program is parametric if it applies a uniform algorithm independently of the type instantiations at which it is applied. The notion of relational parametricity, introduced by Reynolds, is one possible mathematical formulation of this idea. Relational parametricity provides a powerful tool for establishing data abstraction properties, proving equivalences of datatypes, and establishing equalities of programs. Such properties have been well studied in a pure functional setting. Many programs, however, exhibit computational effects, and are not accounted for by the standard theory of relational parametricity. In this paper, we develop a foundational framework for extending the notion of relational parametricity to programming languages with effects.

  5. Note on New KLT relations

    OpenAIRE

    Feng, B.; He, S.; R. Huang; Jia, Y.

    2010-01-01

    In this short note, we present two results about KLT relations discussed in recent several papers. Our first result is the re-derivation of Mason-Skinner MHV amplitude by applying the S_{n-3} permutation symmetric KLT relations directly to MHV amplitude. Our second result is the equivalence proof of the newly discovered S_{n-2} permutation symmetric KLT relations and the well-known S_{n-3} permutation symmetric KLT relations. Although both formulas have been shown to be correct by BCFW recurs...

  6. SUMS Counts-Related Projects

    Data.gov (United States)

    Social Security Administration — Staging Instance for all SUMs Counts related projects including: Redeterminations/Limited Issue, Continuing Disability Resolution, CDR Performance Measures, Initial...

  7. Team incentives in relational contracts

    International Nuclear Information System (INIS)

    Incentive schemes for teams are compared. I ask: under which conditions are relational incentive contracts based on joint performance evaluation, relative performance evaluation and independent performance evaluation self-enforceable. The framework of Che and Yoo (2001) on team incentives is combined with the framework of Baker, Gibbons and Murphy (2002) on relational contracts. In a repeated game between one principal and two agents, I find that incentives based on relative or independent performance are expected to dominate when the productivity of effort is high, while joint performance evaluation dominates when productivity is low. Incentives based on independent performance are more probable if the agents own critical assets. (author)

  8. Optimality of entropic uncertainty relations

    Energy Technology Data Exchange (ETDEWEB)

    Abdelkhalek, Kais; Duhme, Joerg; Schwonnek, Rene; Werner, Reinhard F. [Institut fuer Theoretische Physik, Leibniz Universitaet Hannover, Hannover (Germany); Englert, Berthold-Georg; Raynal, Philippe [Centre for Quantum Technologies and Department of Physics, National University of Singapore (Singapore); Furrer, Fabian [Department of Physics, Graduate School of Science, University of Tokyo, Tokyo (Japan); Maassen, Hans [Department of Mathematics, Radboud University, Nijmegen (Netherlands)

    2014-07-01

    We investigate the optimality of the entropic uncertainty relation proven by Maassen and Uffink and its generalisation to side information from Berta et al for observables, for which the lower bound attains its maximal value. Here, we call an uncertainty relation optimal if the lower bound can be attained for any value of either of the corresponding uncertainties. We show that the uncertainty relation with side information cannot be optimised. In the case of the Maassen-Uffink uncertainty relation, we disprove a conjecture by Englert et al and provide a characterisation of those states that parametrise the optimal lower bound. This leads to a new conjecture.

  9. Basic relativity. An introductory essay

    International Nuclear Information System (INIS)

    This Brief presents a new way of introducing relativity theory, in which perplexing relativistic effects such as time dilation and Lorentz contraction are explained prior to the discussion of Lorentz-transformation. The notion of relativistic mass is shown to contradict the spirit of relativity theory and the true significance of the mass-energy relation is contrasted with the popular view of it. The author discusses the twin paradox from the point of view of both siblings. Last but not least, the fundamentals of general relativity are described, including the recent Gravity Probe B experiment. (orig.)

  10. Remarks on turbulent constitutive relations

    Science.gov (United States)

    Shih, Tsan-Hsing; Lumley, John L.

    1993-01-01

    The paper demonstrates that the concept of turbulent constitutive relations can be used to construct general models for various turbulent correlations. Some of the Generalized Cayley-Hamilton formulas for relating tensor products of higher extension to tensor products of lower extension are introduced. The combination of dimensional analysis and invariant theory can lead to 'turbulent constitutive relations' (or general turbulence models) for, in principle, any turbulent correlations. As examples, the constitutive relations for Reynolds stresses and scalar fluxes are derived. The results are consistent with ones from Renormalization Group (RNG) theory and two-scale Direct-Interaction Approximation (DIA) method, but with a more general form.

  11. The principle of relativity and the indeterminacy of special relativity

    International Nuclear Information System (INIS)

    This work ends a trilogy devoted to a journey into the foundations of special relativity. The first paper debated the meaning of the constancy of the two-way speed of light and its close relation to the conceptualization of time. The second one addressed the question of the possible constancy of the one-way speed of light and the trivial-but, unfortunately, even now somewhat controversial-question of the compatibility between the assumption of a special system of reference and Einstein's special relativity. The present study deals with the principle of relativity. Its historical evolution is reviewed and a 'weak' formulation is defended. It is emphasized that many assertions usually associated with special relativity, such as the 'relativity of time dilation' and 'relativity of space contraction' are indeed philosophical statements, as it has been established already by several authors in the past. Nonetheless, most teachers and scientists still believe nowadays they are implied by the theory and by the group property of the Lorentz transformation. This is by no means so, as it is reviewed and elucidated with the simple example on space contraction. It is argued that the lack of knowledge of the true value of the one-way speed of light in empty space leaves the theory undetermined. Einstein's special relativity corresponds to a simple and very elegant solution to this problem, allowing the study of relative motion without any concern with the study of absolute motion, which is considered to be superfluous. However, its standard interpretation is minimalist and even misleading. A large number of researchers have discussed this question, mostly within the conventionality of simultaneity thesis. The typical formulation of this thesis provides some new physical insight and points out the problem, but does not solve it. In contrast, it often leads to a labyrinth of difficult language which is herein clarified

  12. Equivalence Relations of -Algebra Extensions

    Indian Academy of Sciences (India)

    Changguo Wei

    2010-04-01

    In this paper, we consider equivalence relations of *-algebra extensions and describe the relationship between the isomorphism equivalence and the unitary equivalence. We also show that a certain group homomorphism is the obstruction for these equivalence relations to be the same.

  13. Complementarity and the uncertainty relations

    CERN Document Server

    Björk, G; Trifonov, A S; Tsegaye, T; Karlsson, A M; Bjork, Gunnar; Soderholm, Jonas; Trifonov, Alexei; Tsegaye, Tedros; Karlsson, Anders

    1999-01-01

    We formulate a general complementarity relation starting from any Hermitian operator with discrete non-degenerate eigenvalues. We then elucidate the relationship between quantum complementarity and the Heisenberg-Robertson's uncertainty relation. We show that they are intimately connected. Finally we exemplify the general theory with some specific suggested experiments.

  14. NEW WIND WAVE GROWTH RELATIONS

    Institute of Scientific and Technical Information of China (English)

    WU Shu-ping; HOU Yi-jun; YIN Bao-shu

    2004-01-01

    In the present paper combining the relationship between wave steepness and wave age with the significant wave energy balance equation for wind wave,a new wind wave growth relation is presented.Comparisons with the other existing wind wave growth relations show that the results in present paper accord better with the wind wave growth process.

  15. Simulation in International Relations Education.

    Science.gov (United States)

    Starkey, Brigid A.; Blake, Elizabeth L.

    2001-01-01

    Discusses the educational implications of simulations in international relations. Highlights include the development of international relations simulations; the role of technology; the International Communication and Negotiation Simulations (ICONS) project at the University of Maryland; evolving information technology; and simulating real-world…

  16. Internationalizing the Public Relations Curriculum.

    Science.gov (United States)

    Taylor, Maureen

    2001-01-01

    Discusses broadening public relations to an international level by incorporating the topics of culture, international practices, and culturally sensitive theory development. Discusses rationale, design, and execution of an undergraduate course in international public relations. Suggests ways to incorporate assignments addressing international…

  17. New technologies in public relations

    Directory of Open Access Journals (Sweden)

    Dariusz Tworzydło

    2013-12-01

    Full Text Available The article includes an analysis and presentation of selected examples of communication tools, which are used in companies to create and maintain relationships with internal and external environment. The problems related with definition of public relations were also discussed. The article presents the advantage and negative consequences of the use of modern tools of PR, as well.

  18. Training Guidelines for Employee Relations.

    Science.gov (United States)

    Hotel and Catering Training Board, Wembley (England).

    This set of guidelines is intended for use by employers desiring to establish the training needs of those involved in employee relations. The 16 guidelines cover the following principal activities normally associated with employee relations: staff management policy and aims, staff recruitment and selection, terms and conditions of employment,…

  19. Teaching Special Relativity without Calculus

    Science.gov (United States)

    Ruby, Lawrence

    2009-01-01

    In 2007 many AAPT members received a booklet that is the first chapter of a physics textbook available on a CD. This book espouses the new educational philosophy of teaching special relativity as the first item in the topic of mechanics. Traditionally, special relativity is part of one or more modern physics chapters at the end of the text, and…

  20. Fluctuation Relation for Heat Engines

    OpenAIRE

    Sinitsyn, N. A.

    2011-01-01

    We derive the exact equality, referred to as the fluctuation relation for heat engines (FRHE), that relates statistics of heat extracted from one of the two heat baths and the work per one cycle of a heat engine operation. Carnot's inequality of classical thermodynamics follows as a direct consequence of the FRHE.