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Here we combine observations of open clusters (OCs) with single- and binary population synthesis models and a Galactic potential to reconstruct the SN activity of these OCs during the past 35 Myr. We find that several OCs potentially…

太阳与恒星天体物理 · 物理学 2017-08-29 Mads Sørensen , Henrik Svensmark , Uffe Gråe Jørgensen

Live $^{60}$Fe has recently been reported in a deep-ocean ferromanganese crust. Analysis of the isotopic ratios in the sample suggests that the measured $^{60}$Fe abundance exceeds the levels generated by terrestrial and cosmogenic sources,…

天体物理学 · 物理学 2009-09-11 Brian D. Fields , John Ellis

The probability of occurrence of extreme solar particle events (SPEs) with the fluence of (>30 MeV) protons F30>10^{10} cm^{-2} is evaluated based on data of cosmogenic isotopes 14C and 10Be in terrestrial archives centennial-millennial…

太阳与恒星天体物理 · 物理学 2013-05-23 I. G. Usoskin , G. A. Kovaltsov

The Sun is located in a low-density region of the interstellar medium partially filled with hot gas that is the likely result of several nearby supernova explosions within the last 10 Myr. Here we use astrometric data to show that part of…

天体物理学 · 物理学 2016-08-16 Jesús Maíz-Apellániz

Supernova explosions are one of the most energetic--and potentially lethal--phenomena in the Universe. Scientists have speculated for decades about the possible consequences for life on Earth of a nearby supernova, but plausible candidates…

天体物理学 · 物理学 2009-11-07 Narciso Benitez , Jesus Maiz-Apellaniz , Matilde Canelles

Superdense massive galaxies (r_e~1 kpc; M~10^{11} Msun) were common in the early universe (z>1.5). Within some hierarchical merging scenarios, a non-negligible fraction (1-10%) of these galaxies is expected to survive since that epoch…

Observations of open star clusters in the solar neighborhood are used to calculate local supernova (SN) rates for the past 510 million years (Myr). Peaks in the SN rates match passages of the Sun through periods of locally increased cluster…

太阳与恒星天体物理 · 物理学 2012-10-11 Henrik Svensmark

Based on early solar system abundances of short-lived radionuclides (SRs), such as $^{26}$Al (T$_{1/2} = 0.74$ Myr) and $^{60}$Fe (T$_{1/2} = 1.5$ Myr), it is often asserted that the Sun was born in a large stellar cluster, where a massive…

天体物理学 · 物理学 2017-04-26 Gounelle Meibom

We report the results of spectroscopic observations, obtained with the Gemini North Multi-Object Spectrograph, of 9 planetary nebulae (PNe) and 15 \hii\ regions located in the 5.5\arcmin $\times$5.5\arcmin inner region of the nearby…

宇宙学与河外天体物理 · 物理学 2015-05-13 Laura Magrini , Denise R. Goncalves

We present a study of the abundance of Be stars in open clusters as a function of the cluster age, using whenever possible ages determined through Stromgren uvby photometry. For the first time in studies of this kind we have considered…

天体物理学 · 物理学 2007-05-23 Juan Fabregat , J. Miguel Torrejon

We present analysis of HST U,V,I, and Halpha images of the peculiar Local Group irregular galaxy IC 10. The images are used to determine the nature of the stellar products in a portion of the recent starburst in this galaxy. We identified…

天体物理学 · 物理学 2009-11-06 Deidre A. Hunter

We summarize evidence that multiple supernovae exploded within 100 pc of Earth in the past few Myr. These events had dramatic effects on the heliosphere, compressing it to within ~20 au. We advocate for cross-disciplinary research of nearby…

We revisited assessments of the occurrence probability distribution of large events in solar energetic particles (SEP), based on measurements of cosmogenic radionuclides in lunar rocks. We present a combined cumulative occurrence…

太阳与恒星天体物理 · 物理学 2014-01-17 Gennady A. Kovaltsov , Ilya G. Usoskin

We investigate the distribution of bright main sequence stars near the northern edge of the M33 disk. Clustering on sub-kpc scales is seen among stars with ages near 10 Myr, and two large star-forming complexes are identified. Similar…

星系天体物理 · 物理学 2015-05-20 T. J. Davidge , T. H. Puzia , A. W. McConnachie

We study arrival directions of 1.4x10^6 extensive air showers (EAS) registered with the EAS--1000 Prototype Array in the energy range 0.1--10 PeV. By applying an iterative algorithm that provides uniform distribution of the data with…

天体物理学 · 物理学 2007-05-23 G. V. Kulikov , M. Yu. Zotov

Recent works suggest there are periods when the Sun encountered massive interstellar cold clouds which compressed the heliosphere to within Earth's orbit. This would expose Earth to increased galactic cosmic rays (GCRs) and energetic…

地球与行星天体物理 · 物理学 2026-03-25 Anna Nica , Merav Opher , Jesse A. Miller , Jennifer L. Middleton

(Abridged) We present high-resolution HST imaging in the optical (WFPC2) and near-infrared (NICMOS) of a disk region 1 kpc NE of the starburst core in the nearby galaxy M82. This region, M82 ``B,'' has been suspected to be a fossil…

天体物理学 · 物理学 2019-08-17 Richard de Grijs , Robert W. O'Connell , John S. Gallagher , III

Open clusters are distributed all across the disk and are convenient tracers of its properties. In particular, outer disk clusters bear a key role for the investigation of the chemical evolution of the Galactic disk. The goal of this study…

星系天体物理 · 物理学 2016-03-30 T. Cantat-Gaudin , P. Donati , A. Vallenari , R. Sordo , A. Bragaglia , L. Magrini

We present a numerical code designed to conduct a likelihood analysis for clusters of nucleons above 10**19 eV originating from discrete astrophysical sources such as powerful radio galaxies, gamma-ray bursts or topological defects. The…

天体物理学 · 物理学 2009-12-30 Guenter Sigl , Martin Lemoine , Angela V. Olinto

Sensitive high angular resolution ($\sim$ 2$"$) CO(2-1) line observations made with the Submillimeter Array (SMA) of the flow emanating from the high-mass star forming region DR21 located in the Cygnus X molecular cloud are presented. These…

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