7,105 research outputs found
The Abell 85 BCG: a nucleated, core-less galaxy
New high-resolution r band imaging of the brightest cluster galaxy (BCG) in
Abell 85 (Holm 15A) was obtained using the Gemini Multi Object Spectrograph.
These data were taken with the aim of deriving an accurate surface brightness
profile of the BCG of Abell 85, in particular its central region. The new
Gemini data show clear evidence of a previously unreported nuclear emission
that is evident as a distinct light excess in the central kiloparsec of the
surface brightness profile. We find that the light profile is never flat nor
does it present a downward trend towards the center of the galaxy. That is, the
new Gemini data show a different physical reality from the featureless,
"evacuated core" recently claimed for the Abell 85 BCG. After trying different
models, we find that the surface brightness profile of the BCG of Abell 85 is
best fit by a double Sersic model.Comment: Gemini web feature: Supermassive black hole that wasn't -
http://gemini.edu/node/1247
Periodic Modulation Induced Increase of Reaction Rates in Autocatalytic Systems
We propose a new mechanism to increase the reactions ratesin multistable
autocatalytic systems. The mechanism is based upon the possibility for the
enhancement of the response of the system due to the cooperative behavior
between the noise and an external periodic modulation. In order to illustrate
this feature we compute the reaction velocities for the particular case of the
Sel'Kov model, showing that they increase significantly when the periodic
modulation is introduced. This behavior originates from the existence of a
minimum in the mean first passage time, one of the signatures of stochastic
resonance.Comment: Submitted to J. Chem. Phy
Reply to ``Comment on `On the inconsistency of the Bohm-Gadella theory with quantum mechanics'''
In this reply, we show that when we apply standard distribution theory to the
Lippmann-Schwinger equation, the resulting spaces of test functions would
comply with the Hardy axiom only if classic results of Paley and Wiener, of
Gelfand and Shilov, and of the theory of ultradistributions were wrong. As
well, we point out several differences between the ``standard method'' of
constructing rigged Hilbert spaces in quantum mechanics and the method used in
Time Asymmetric Quantum Theory.Comment: 13 page
Nonequilibrium Stefan-Boltzmann law
We study thermal radiation outside equilibrium. The situation considered
consists of two bodies emitting photons at two different temperatures. We show
that the system evolves to a stationary state characterized by an energy
current which satisfies a Stefan-Boltzmann-like law expressing it as the
difference of the temperatures to the fourth power of the emitters . The
results obtained show how the classical laws governing the thermal radiation at
equlibrium can be generalized away from equilibrium situations.Comment: 9 pages, 1 figure. To be published in J. Noneq. Ther
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