1,072 research outputs found

    Internationalization and Financial Federalism: The United States and Germany at the Crossroads?

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    In this article, the authors examine some effects of economic internationalization on state structures, especially in regard to the distribution of power and authority within federalist systems. Using an institutional rational choice model, they analyze changes in financial regulation and market structures in Germany and the United States. The focus is on the financial realm because of its high degree of internationalization and because, in both countries, financial markets and regulation have historically exhibited federalist traits. The findings indicate that internationalization has led to significant convergence in financial market structures and regulation across the two countries and that in each case this convergence has been accompanied by centralization of financial regulatory authority. Although both the German type of cooperative federalism and the U.S. model of competitive federalism proved to be vulnerable to the growing international pressures, the two countries took different paths of change that reflected differences in domestic institutions. Thus, the authors conclude that convergence is, and will likely remain, of a limited nature

    CoRoT 101186644: A transiting low-mass dense M-dwarf on an eccentric 20.7-day period orbit around a late F-star

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    We present the study of the CoRoT transiting planet candidate 101186644, also named LRc01_E1_4780. Analysis of the CoRoT lightcurve and the HARPS spectroscopic follow-up observations of this faint (m_V = 16) candidate revealed an eclipsing binary composed of a late F-type primary (T_eff = 6090 +/- 200 K) and a low-mass, dense late M-dwarf secondary on an eccentric (e = 0.4) orbit with a period of ~20.7 days. The M-dwarf has a mass of 0.096 +/- 0.011 M_Sun, and a radius of 0.104 +0.026/-0.006 R_Sun, which possibly makes it the smallest and densest late M-dwarf reported so far. Unlike the claim that theoretical models predict radii that are 5%-15% smaller than measured for low-mass stars, this one seems to have a radius that is consistent and might even be below the radius predicted by theoretical models.Comment: Accepted for publication in Astronomy & Astrophysics, 8 pages, 10 figure

    Ground-based photometry of space-based transit detections: Photometric follow-up of the CoRoT mission

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    The motivation, techniques and performance of the ground-based photometric follow-up of transit detections by the CoRoT space mission are presented. Its principal raison d'\^{e}tre arises from the much higher spatial resolution of common ground-based telescopes in comparison to CoRoT's cameras. This allows the identification of many transit candidates as arising from eclipsing binaries that are contaminating CoRoT's lightcurves, even in low-amplitude transit events that cannot be detected with ground-based obervations. For the ground observations, 'on'-'off' photometry is now largely employed, in which only a short timeseries during a transit and a section outside a transit is observed and compared photometrically. CoRoT planet candidates' transits are being observed by a dedicated team with access to telescopes with sizes ranging from 0.2 to 2 m. As an example, the process that led to the rejection of contaminating eclipsing binaries near the host star of the Super-Earth planet CoRoT-7b is shown. Experiences and techniques from this work may also be useful for other transit-detection experiments, when the discovery instrument obtains data with a relatively low angular resolution.Comment: Accepted for the A&A special issue on CoRo

    Radio Continuum and Star Formation in CO-rich Early Type Galaxies

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    In this paper we present new high resolution VLA 1.4 GHz radio continuum observations of five FIR bright CO-rich early-type galaxies and two dwarf early-type galaxies. The position on the radio-FIR correlation combined with striking agreements in morphology between high resolution CO and radio maps show that the radio continuum is associated with star formation in at least four of the eight galaxies. The average star formation rate for the sample galaxies detected in radio is approximately 2 solar masses per year. There is no evidence of a luminous AGN in any of our sample galaxies. We estimate Toomre Q values and find that the gas disks may well be gravitationally unstable, consistent with the above evidence for star formation activity. The radio continuum emission thus corroborates other recent suggestions that star formation in early type galaxies may not be uncommon.Comment: 21 pages, 7 figures, to be published in the Astronomical Journa

    High angular resolution imaging and infrared spectroscopy of CoRoT candidates

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    Studies of transiting extrasolar planets are of key importance for understanding the nature of planets outside our solar system because their masses, diameters, and bulk densities can be measured. An important part of transit-search programmes is the removal of false-positives. The critical question is how many of the candidates that passed all previous tests are false positives. For our study we selected 25 CoRoT candidates that have already been screened against false-positives using detailed analysis of the light curves and seeing-limited imaging, which has transits that are between 0.7 and 0.05% deep. We observed 20 candidates with the adaptive optics imager NaCo and 18 with the high-resolution infrared spectrograph CRIRES. We found previously unknown stars within 2 arcsec of the targets in seven of the candidates. All of these are too faint and too close to the targets to have been previously detected with seeing-limited telescopes in the optical. Our study thus leads to the surprising results that if we remove all candidates excluded by the sophisticated analysis of the light-curve, as well as carrying out deep imaging with seeing-limited telescopes, still 28-35% of the remaining candidates are found to possess companions that are bright enough to be false-positives. Given that the companion-candidates cluster around the targets and that the J-K colours are consistent with physical companions, we conclude that the companion-candidates are more likely to be physical companions rather than unrelated field stars.Comment: 12 pages, 12 figures, A&A in pres

    The HARPS search for southern extra-solar planets XXXII. Only 4 planets in the Gl~581 system

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    The Gl 581 planetary system has generated wide interest, because its 4 planets include both the lowest mass planet known around a main sequence star other than the Sun and the first super-Earth planet in the habitable zone of its star. A recent paper announced the possible discovery of two additional super-Earth planets in that system, one of which would be in the middle of the habitable zone of Gl 581. The statistical significance of those two discoveries has, however, been questioned. We have obtained 121 new radial velocity measurements of Gl 581 with the HARPS spectrograph on the ESO 3.6 m telescope, and analyse those together with our previous 119 measurements of that star to examine these potential additional planets. We find that neither is likely to exist with their proposed parameters. We also obtained photometric observations with the 2.5 m Isaac Newton Telescope during a potential transit of the inner planet, Gl 581e, which had a 5% geometric transit probability. Those observations exclude transits for planet densities under 4 times the Earth density within -0.2 sigma to +2.7 sigma of the predicted transit center.Comment: Submitted to Astronomy & Astrophysic

    Revisiting the transits of CoRoT-7b at a lower activity level

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    CoRoT-7b, the first super-Earth with measured radius discovered, has opened the new field of rocky exoplanets characterisation. To better understand this interesting system, new observations were taken with the CoRoT satellite. During this run 90 new transits were obtained in the imagette mode. These were analysed together with the previous 151 transits obtained in the discovery run and HARPS radial velocity observations to derive accurate system parameters. A difference is found in the posterior probability distribution of the transit parameters between the previous CoRoT run (LRa01) and the new run (LRa06). We propose this is due to an extra noise component in the previous CoRoT run suspected to be transit spot occultation events. These lead to the mean transit shape becoming V-shaped. We show that the extra noise component is dominant at low stellar flux levels and reject these transits in the final analysis. We obtained a planetary radius, Rp=1.585±0.064RR_p= 1.585\pm0.064\,R_{\oplus}, in agreement with previous estimates. Combining the planetary radius with the new mass estimates results in a planetary density of 1.19±0.27ρ 1.19 \pm 0.27\, \rho_{\oplus} which is consistent with a rocky composition. The CoRoT-7 system remains an excellent test bed for the effects of activity in the derivation of planetary parameters in the shallow transit regime.Comment: 13 pages, 13 figures, accepted to A&

    Kepler423b: a half-Jupiter mass planet transiting a very old solar-like star

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    We report the spectroscopic confirmation of the Kepler object of interest KOI-183.01 (Kepler-423b), a half-Jupiter mass planet transiting an old solar-like star every 2.7 days. Our analysis is the first to combine the full Kepler photometry (quarters 1-17) with high-precision radial velocity measurements taken with the FIES spectrograph at the Nordic Optical Telescope. We simultaneously modelled the photometric and spectroscopic data-sets using Bayesian approach coupled with Markov chain Monte Carlo sampling. We found that the Kepler pre-search data conditioned (PDC) light curve of KOI-183 exhibits quarter-to-quarter systematic variations of the transit depth, with a peak-to-peak amplitude of about 4.3 % and seasonal trends reoccurring every four quarters. We attributed these systematics to an incorrect assessment of the quarterly variation of the crowding metric. The host star KOI-183 is a G4 dwarf with M=0.85±0.04M_\star=0.85\pm0.04 M_\rm{Sun}, R=0.95±0.04R_\star=0.95\pm0.04 R_\rm{Sun}, Teff=5560±80T_\mathrm{eff}=5560\pm80 K, [M/H]=0.10±0.05[M/H]=-0.10\pm0.05 dex, and with an age of 11±211\pm2 Gyr. The planet KOI-183b has a mass of Mp=0.595±0.081M_\mathrm{p}=0.595\pm0.081 MJup_\mathrm{Jup} and a radius of Rp=1.192±0.052R_\mathrm{p}=1.192\pm0.052 RJup_\mathrm{Jup}, yielding a planetary bulk density of ρp=0.459±0.083\rho_\mathrm{p}=0.459\pm0.083 g/cm3^{3}. The radius of KOI-183b is consistent with both theoretical models for irradiated coreless giant planets and expectations based on empirical laws. The inclination of the stellar spin axis suggests that the system is aligned along the line of sight. We detected a tentative secondary eclipse of the planet at a 2-σ\sigma confidence level (ΔFec=14.2±6.6\Delta F_{\mathrm{ec}}=14.2\pm6.6 ppm) and found that the orbit might have a small non-zero eccentricity of e=0.0190.014+0.028e=0.019^{+0.028}_{-0.014}. With a Bond albedo of AB=0.037±0.019A_\mathrm{B}=0.037\pm0.019, KOI-183b is one of the gas-giant planets with the lowest albedo known so far.Comment: 13 pages, 13 figures, 5 tables. Accepted for publication in A&A. Planet designation changed from KOI-183b to Kepler-423

    Detection of Neptune-size planetary candidates with CoRoT data. Comparison with the planet occurrence rate derived from Kepler

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    [Abridged] Context. The CoRoT space mission has been searching for transiting planets since the end of December 2006. Aims. We aim to investigate the capability of CoRoT to detect small-size transiting planets in short-period orbits, and to compare the number of CoRoT planets with 2 \leq R_p \leq 4 Rearth with the occurrence rate of small-size planets provided by the distribution of Kepler planetary candidates (Howard et al. 2012). Methods. We performed a test that simulates transits of super-Earths and Neptunes in real CoRoT light curves and searches for them blindly by using the LAM transit detection pipeline. Results. The CoRoT detection rate of planets with radius between 2 and 4 Rearth and orbital period P \leq 20 days is 59% (31%) around stars brighter than r'=14.0 (15.5). By properly taking the CoRoT detection rate for Neptune-size planets and the transit probability into account, we found that according to the Kepler planet occurrence rate, CoRoT should have discovered 12 \pm 2 Neptunes orbiting G and K dwarfs with P \leq 17 days in six observational runs. This estimate must be compared with the validated Neptune CoRoT-24b and five CoRoT planetary candidates in the considered range of planetary radii. We thus found a disagreement with expectations from Kepler at 3 \sigma or 5 \sigma, assuming a blend fraction of 0% (six Neptunes) and 100% (one Neptune) for these candidates. Conclusions. This underabundance of CoRoT Neptunes with respect to Kepler may be due to several reasons. Regardless of the origin of the disagreement, which needs to be investigated in more detail, the noticeable deficiency of CoRoT Neptunes at short orbital periods seems to indirectly support the general trend found in Kepler data, i.e. that the frequency of small-size planets increases with increasing orbital periods and decreasing planet radii.Comment: 10 pages, 7 figures. Accepted for publication in A&
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