نتایج جستجو برای: supernovae
تعداد نتایج: 8280 فیلتر نتایج به سال:
While the modern stellar IMF shows a rapid decline with increasing mass, theoretical investigations suggest that very massive stars (& 100M⊙) may have been abundant in the early universe. Other calculations also indicate that, lacking metals, these same stars reach their late evolutionary stages without appreciable mass loss. After central helium burning, they encounter the electron-positron pa...
The variation of the fine structure constant: testing the dipole model with thermonuclear supernovae
The large-number hypothesis conjectures that fundamental constants may vary. Accordingly, the spacetime variation of fundamental constants has been an active subject of research for decades. Recently, using data obtained with large telescopes a phenomenological model in which the fine structure constant might vary spatially has been proposed. We test whether this hypothetical spatial variation ...
The unexpected faintness of high-redshift Type Ia supernovae (SNe Ia), as measured by two teams, has been interpreted as evidence that the expansion of the Universe is accelerating. We review the current challenges to this interpretation and seek to answer whether the cosmological implications are compelling. We discuss future observations of SNe Ia which could offer extraordinary evidence to t...
Recent nucleosynthesis calculations of Type II supernovae using advanced neutrino transport determine that the early neutrino winds are proton-rich. However, a fraction of the ejecta emitted at the same time is composed of neutron-rich pockets. In this paper we calculate the nucleosynthesis contribution from the neutron-rich pockets in the hot convective bubbles of a core-collapse supernova and...
We have developed a technique to systematically discover and study high-redshift supernovae that can be used to measure the cosmological parameters. We report here results based on the initial seven of >28 supernovae discovered to date in the high-redshift supernova search of the Supernova Cosmology Project. We nd an observational dispersion in peak magnitudes of M B = 0:27; this dispersion nar...
We examine the origin and evolution of the mass-metallicity relationship (M∗-Z) for galaxies using high resolution cosmological SPH + N-Body simulations that include a physically motivated description of the effects of supernovae feedback and subsequent metal enrichment. Our simulations allow us to distinguish between two possible sources that contribute to both the origin of the mass-metallici...
The recent detection of Hα emission in the supernova Type Ia SN 2002ic could be taken to mean that the elusive progenitor systems of Type Ia supernovae have finally been identified. At first glance, the observation appears to support a single-degenerate scenario, in which the white dwarf accretes from a normal companion. In this Letter we show that the opposite may be true, and the observations...
The thermalized energy from the radioactive decays of Ni and Ni and their daughter nuclides power the light curves of supernovae near maximum light. The bolometric light curve gives us a fundamental understanding of the energy evolution of a supernova explosion and the amount of radioactive nuclides produced. In this review, I will discuss the bolometric evolution of the Type IIp supernovae SN1...
We cross-correlate the sample of Type Ia supernovae from Riess et al. (2004) with the SDSS DR2 photometric galaxy catalogue. In contrast to recent work, we find no detectable correlation between supernova magnitude and galaxy overdensity on scales ranging between 1 − 10. Our results are in accord with theoretical expectations for gravitational lensing of supernovae by large-scale structure. Fut...
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