Do extragalactic cosmic rays induce cycles in fossil diversity? / Medvedev Mikhail V.,Melott Adrian L. // ASTROPHYSICAL JOURNAL. - 2007. - V. 664, l. 2, 1. - P. 879-889.

ISSN/EISSN:

0004-637X / нет данных

Type:

Article

Abstract:

Recent work has revealed a 62 +/- 3 Myr cycle in fossil diversity in the past 542 Myr; however, no plausible mechanism has been found. We propose that the cycle may be caused by modulation of cosmic-ray (CR) flux by the solar system vertical oscillation (64 Myr period) in the Galaxy, the Galactic north-south anisotropy of CR production in the Galactic halo/wind/termination shock (due to the Galactic motion toward the Virgo Cluster), and the shielding by Galactic magnetic fields. We revisit the mechanism of CR propagation and show that CR flux can vary by a factor of about 4.6 and reach a maximum at northernmost displacement of the Sun. The very high statistical significance of (1) the phase agreement between solar northward excursions and the diversity minima and (2) the correlation of the magnitude of diversity drops with CR amplitudes through all cycles provide solid support for our model. Various observational predictions which can be used to confirm or falsify our hypothesis are presented.

Author keywords:

acceleration of particles; astrobiology; diffusion; galaxy : general; magnetic fields; shock waves THERMAL CONDUCTION; GALACTIC WIND; LOCAL BUBBLE; HIPPARCOS; ORIGIN; UNIVERSE; DENSITY; GALAXY; GAS; EXTINCTION

DOI:

10.1086/518757

Web of Science ID:

ISI:000248675000022

Соавторы в МНС:

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Другие поля

Поле	Значение
Month	AUG 1
Publisher	UNIV CHICAGO PRESS
Address	1427 E 60TH ST, CHICAGO, IL 60637-2954 USA
Language	English
Keywords-Plus	THERMAL CONDUCTION; GALACTIC WIND; LOCAL BUBBLE; HIPPARCOS; ORIGIN; UNIVERSE; DENSITY; GALAXY; GAS; EXTINCTION
Research-Areas	Astronomy \& Astrophysics
Web-of-Science-Categories	Astronomy \& Astrophysics
Number-of-Cited-References	70
Usage-Count-Since-2013	9
Journal-ISO	Astrophys. J.
Doc-Delivery-Number	199CY