An astrophysical constraint
نویسندگان
چکیده
منابع مشابه
Astrophysical axion bounds: An update
The observed properties of stars and especially the neutrino signal of the supernova 1987A provide an upper limit to the axion mass, while the age and expansion rate of the universe provide a lower limit. There remains a “window of opportunity” 10 eV ∼ < ma ∼ < 10 eV, with large uncertainties on either side, where axions could still exist and where they would provide a significant fraction or a...
متن کاملIS COSMOLOGY SOLVED? An Astrophysical Cosmologist’s Viewpoint
We have fossil evidence from the thermal background radiation that our universe expanded from a considerably hotter denser state. We have a well defined, testable, and so far quite successful theoretical description of the expansion: the relativistic FriedmannLemâıtre cosmological model. The observational successes of this model are impressive but I think hardly enough for a convincing scientif...
متن کاملNitrate Deposition following an Astrophysical Ionizing Radiation
It is known that a gamma ray burst (GRB) originating near the Earth could be devastating to life. The mechanism of ozone depletion and subsequent increased UVB exposure is the primary risk, but models also show increased nitrification culminating in nitric acid rainout. These effects are also expected after nearby supernovae and extreme solar proton events. In this work we considered specifical...
متن کاملOn Validating an Astrophysical Simulation Code
We present a case study of validating an astrophysical simulation code. Our study focuses on validating FLASH, a parallel, adaptive-mesh hydrodynamics code for studying the compressible, reactive flows found in many astrophysical environments. We describe the astrophysics problems of interest and the challenges associated with simulating these problems. We describe methodology and discuss solut...
متن کاملThe CATS Service: An Astrophysical Research Tool
We describe the current status of CATS (astrophysical CATalogs Support system), a publicly accessible tool maintained at Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS) (http://cats.sao.ru) allowing one to search hundreds of catalogs of astronomical objects discovered all along the electromagnetic spectrum. Our emphasis is mainly on catalogs of radio continuum sou...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Nature
سال: 2003
ISSN: 0028-0836,1476-4687
DOI: 10.1038/4241007a