About the Coma Cluster (Progress Report)

Coma Cluster

Transvaluationism about Vagueness: a Progress Report

The philosophical account of vagueness I call “transvaluationism” makes three fundamental claims. First, vagueness is logically incoherent in a certain way: it essentially involves mutually unsatisfiable requirements that govern vague language, vague thought-content, and putative vague objects and properties. Second, vagueness in language and thought (i.e., semantic vagueness) is a genuine phen...

Qualitative Reasoning about Function: A progress report

One important kind of reasoning in engineering problem solving is reasoning about function. This paper outlines research underway in our group to develop an account of reasoning about function, based on ideas from qualitative physics and motivated by teaching and design tasks. Our approach is based on three ideas: that the semantics of function representations should be based on behaviors, that...

The magnetic field in the Coma cluster

The polarization data of the radio galaxy NGC4869, belonging to the Coma cluster and located in its central region, allow us to obtain information on the structure of magnetic field associated with the cluster itself. A magnetic field of ∼ 8.5 µG, tangled on scales of the order of less than 1 kpc, is required to explain the observed fluctuations of the rotation measure. This magnetic field is m...

Beppo-SAX OBSERVATION OF THE COMA CLUSTER

We present first results of the BeppoSAX observation of the Coma Cluster. Thanks to the unprecedented sensitivity of the PDS instrument, the source has been detected up to ∼80 keV. There is clear evidence for emission in excess to the thermal one above ∼25 keV, very likely of non-thermal origin. We have therefore, for the first time, detected the long sought Inverse Compton emission on CMB phot...