6,722 research outputs found

    Global velocity field and bubbles in the BCD Mrk86

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    We have studied the velocity field of the Blue Compact Dwarf galaxy Mrk86 (NGC2537) using data provided by 14 long-slit optical spectra. This kinematical information is complemented with narrow-band ([OIII]5007A and Halpha) and broad-band (B, V, Gunn-r and K) imaging. The analysis of the galaxy global velocity field suggests that the ionized gas could be distributed in a rotating inclined disk, with projected central angular velocity of Omega=34 km/s/kpc. The comparison between the stellar, HI and modeled dark matter density profile, indicates that the total mass within its optical radius is dominated by the stellar component. Peculiarities observed in its velocity field can be explained by irregularities in the ionized gas distribution or local motions induced by star formation. Kinematical evidences for two expanding bubbles, Mrk86-B and Mrk86-C, are given. They show expanding velocities of 34 km/s and 17 km/s, Halpha luminosities of 3x10^38 erg/s and 1.7x10^39 erg/s, and physical radii of 374 and 120 pc, respectively. The change in the [SII]/Halpha, [NII]/Halpha, [OII]/[OIII] and [OIII]/Hbeta line ratios with the distance to the bubble precursor suggests a diminution in the ionization parameter and, in the case of Mrk86-B, an enhancement of the shock-excited gas emission. The optical-near-infrared colours of the bubble precursors are characteristic of low metallicity star forming regions (0.2 Zsun) with burst strengths of about 1 per cent in mass.Comment: 14 pages, 12 PostScript figures, accepted for publication in MNRAS, also available at ftp://cutrex.fis.ucm.es/pub/OUT/gil/PAPERS

    Measuring work and heat in ultracold quantum gases

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    We propose a feasible experimental scheme to direct measure heat and work in cold atomic setups. The method is based on a recent proposal which shows that work is a positive operator valued measure (POVM). In the present contribution, we demonstrate that the interaction between the atoms and the light polarisation of a probe laser allows us to implement such POVM. In this way the work done on or extracted from the atoms after a given process is encoded in the light quadrature that can be measured with a standard homodyne detection. The protocol allows one to verify fluctuation theorems and study properties of the non-unitary dynamics of a given thermodynamic process.Comment: Published version in the Focus Issue on "Quantum Thermodynamics

    Mapping the star formation history of Mrk86: I. Data and models

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    We have obtained optical (BVR, [OIII]5007 and Halpha), near infrared (JHK) imaging and long-slit optical spectroscopy for the Blue Compact Dwarf galaxy Mrk86 (NGC2537). In this paper, the first of two, we present optical-near- infrared colors and emission-line fluxes for the currently star-forming regions, intemediate aged starburst and underlying stellar population. We also describe the evolutionary synthesis models used in Paper II. The R and Halpha luminosity distributions of the galaxy star-forming regions show maxima at M_R=-9.5 and L_Halpha=10^37.3 erg s^-1. The underlying stellar population shows an exponential surface brigthness profile with central value, mu_E,0=21.5 mag arcsec^-2, and scale, alpha=0.88 kpc, both measured in the R-band image. In the galaxy outer regions, dominated by this component, no significant color gradients are observed. Finally, a set of evolutionary synthesis models have been developed, covering a wide range in metallicity and burst strength.Comment: 21 pages, 14 figures, 2 landscape tables, accepted for publication in Astronomy & Astrophysics Supplement Series, for higher resolution images see ftp://cutrex.fis.ucm.es/pub/OUT/gil/PAPERS/aa00_I.ps.g

    Optical photometry of the UCM Lists I and II

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    We present Johnson B CCD photometry for the whole sample of galaxies of the Universidad Complutense de Madrid (UCM) Survey Lists I and II. They constitute a well-defined and complete sample of galaxies in the Local Universe with active star formation. The data refer to 191 S0 to Irr galaxies at an averaged redshift of 0.027, and complement the already published Gunn r, J and K photometries. In this paper the observational and reduction features are discussed in detail, and the new colour information is combined to search for clues on the properties of the galaxies, mainly by comparing our sample with other surveys.Comment: 14 pages, 7 PostScript figures, accepted for publication in A&AS, also available vi ftp at ftp://cutrex.fis.ucm.es/pub/OUT/pag/PAPERS

    Exotic looped trajectories via quantum marking

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    We provide an analytical and theoretical study of exotic looped trajectories (ELTs) in a double-slit interferometer with quantum marking. We use an excited Rydberg-like atom and which-way detectors such as superconducting cavities, just as in the Scully-Englert-Walther interferometer. We indicate appropriate conditions on the atomic beam or superconducting cavities so that we determine an interference pattern and fringe visibility exclusive from the ELTs. We quantitatively describe our results for Rubidium atoms and propose this framework as an alternative scheme to the double-slit experiment modified to interfere only these exotic trajectories.Comment: 10 pages, 5 figure
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