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Saturday Morning Breakfast Cereal - Get Me a Scientist

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For the rest of her life, when asked about the asteroid's devastation, she would make a joke about Impact Factor.

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Come to my dang show, Houstonoids!

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FuriousClam
241 days ago
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Data *are*
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drchuck
246 days ago
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Deep Impact: how it should have ended?
Long Island, NY

The Hubble diagram in a Bianchi I univers [CEA]

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http://arxiv.org/abs/1601.04965
SchuckerEtAl-1601.04965_f2.jpg SchuckerEtAl-1601.04965_f1.jpg
The Bianchi I metric describes a homogeneous, but anisotropic universe and is commonly used to fit cosmological data. A fit to the angular distribution of 740 supernovae of type Ia with measured redshift and apparent luminosity is presented. It contains an intriguing, yet non-significant signal of a preferred direction in the sky. The Large Synoptic Survey Telescope being built in Chile should measure some 500 000 supernovae within the next 20 years and verify or falsify this signal.

Read this paper on arXiv…

T. Schucker
Wed, 20 Jan 16
36/58

Comments: 6 pages, 2 figures


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FuriousClam
999 days ago
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Spherical Cows!
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Neutrinos from collapsars. (arXiv:1309.6043v1 [astro-ph.HE])

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Long gamma-ray bursts (GRBs) are associated with the gravitational collapse of very massive stars. The central engine of a GRB can collimate relativistic jets that propagate inside the stellar envelope. The shock waves produced when the jet disrupts the stellar surface are capable of accelerating particles up to very high energies. If the jet has hadronic content, neutrinos will be produced via charged pion decays. The main goal of this work is to estimate the neutrino emission produced in the region close to the surface of the star, taking pion and muon cooling into account, along with subtle effects arising from neutrino production in a highly magnetized medium. We estimate the maximum energies of the different kinds of particles and solve the coupled transport equations for each species. Once the particle distributions are known, we calculate the intensity of neutrinos. We study the different effects on the neutrinos that can change the relative weight of different flavors. In particular, we consider the effects of neutrino oscillations, and of neutrino spin precession caused by strong magnetic fields. The expected neutrino signals from the shocks in the uncorking regions of Population III events is very weak, but the neutrino signal produced by Wolf-Rayet GRBs with $z<0.5$ is not far from the level of the atmospheric background. The IceCube experiment does not have the sensitivity to detect neutrinos from the implosion of the earliest stars, but a number of high-energy neutrinos may be detected from nearby long GRBs. The cumulative signal should be detectable over several years ($\sim 10$ yr) of integration with the full 86-string configuration.

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FuriousClam
1847 days ago
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A ~10year integration with the full ICECUBE experiment will give a statistical detection of neutrinos from GRBs. Such a small signal would explain why I have not see neutrinos discussed in the GRB prompt emission literature.
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