1,847 research outputs found
Infrared studies of supernova remnants with the IRAS
A comparative study of the infrared and X-ray fluxes and morphologies of supernova remnants (SNR) can yield valuable information on their evolution and on their interaction with the smbient interstellar medium (ISM)
Krasnoselskii's theorem in generalized Banach spaces and application
The purpose of this paper is to extend Krasnoselskii's fixed point theorem to the case of generalized Banach spaces for singlevalued and multivalued operators. As applications, we will give some existence results for abstract system of Fredholm-Volterra type differential equations and inclusions
CP nonconservation in the leptonic sector
In this paper we use an exact method to impose unitarity on moduli of
neutrino PMNS matrix recently determined, and show how one could obtain
information on CP nonconservation from a limited experimental information. One
suggests a novel type of global fit by expressing all theoretical quantities in
terms of convention independent parameters: the Jarlskog invariant and the
moduli , able to resolve the positivity problem of .
In this way the fit will directly provide a value for , and if it is
different from zero it will prove the existence of CP violation in the
available experimental data. If the best fit result, , from M.
Maltoni {\em et al}, [New J.Phys. {\bf 6} (2004) 122] is confirmed, it will
imply a new physics in the leptonic sector
Chandra X-ray Observation of a Mature Cloud-Shock Interaction in the Bright Eastern Knot Region of Puppis A
We present Chandra X-ray images and spectra of the most prominent cloud-shock
interaction region in the Puppis A supernova remnant. The Bright Eastern Knot
(BEK) has two main morphological components: (1) a bright compact knot that
lies directly behind the apex of an indentation in the eastern X-ray boundary
and (2) lying 1' westward behind the shock, a curved vertical structure (bar)
that is separated from a smaller bright cloud (cap) by faint diffuse emission.
Based on hardness images and spectra, we identify the bar and cap as a single
shocked interstellar cloud. Its morphology strongly resembles the ``voided
sphere'' structures seen at late times in Klein et al.'s experimental
simulations of cloud-shock interactions, when the crushing of the cloud by
shear instabilities is well underway. We infer an interaction time of roughly 3
cloud-crushing timescales, which translates to 2000-4000 years, based on the
X-ray temperature, physical size, and estimated expansion of the shocked cloud.
This is the first X-ray identified example of a cloud-shock interaction in this
advanced phase. Closer to the shock front, the X-ray emission of the compact
knot in the eastern part of the BEK region implies a recent interaction with
relatively denser gas, some of which lies in front of the remnant. The complex
spatial relationship of the X-ray emission of the compact knot to optical [O
III] emission suggests that there are multiple cloud interactions occurring
along the line of sight.Comment: 22 pages LaTeX with multiple figures, to appear in Ap
Deep optical observations of the central X-ray source in the Puppis A supernova remnant
X-ray observations reveiled a group of radio-silent isolated neutron stars
(INSs) at the centre of young supernova remnants (SNRs), dubbed central compact
objects or CCOs, with properties different from those of classical
rotation-powered pulsars. In at least three cases, evidence points towards CCOs
being low-magnetized INSs, born with slow rotation periods, and possibly
accreting from a debris disc of material formed out of the supernova event.
Understanding the origin of the diversity of the CCOs can shed light on
supernova explosion and neutron star formation models. Optical/infrared (IR)
observations are crucial to test different CCO interpretations. The aim of our
work is to perform a deep optical investigation of the CCO RX J0822.0-4300 in
the Puppis A SNR, one of the most poorly understood in the CCO family. By using
as a reference the Chandra X-ray coordinates of RX J0822.0-4300, we performed
deep optical observations in the B, V and I bands with the Very Large Telescope
(VLT). We found no candidate optical counterpart within 3 sigma of the computed
Chandra X-ray position down to 5 sigma limits of B~27.2, V~26.9, and I~25.6,
the deepest obtained in the optical band for this source. These limits confirm
the non-detection of a companion brighter than an M5 dwarf. At the same time,
they do not constrain optical emission from the neutron star surface, while
emission from the magnetosphere would require a spectral break in the
optical/IR.Comment: 4 pages, 2 figures, Astronomy and Astrophysics, accepte
New Services to Enhance a Health Care Network\u27s Reputation: Digital Commons at LVHN, A Health Network Experience
Live for a little over two years, Lehigh Valley Health Network’s repository, LVHN Scholarly Works, has enhanced the Network’s reputation and research credibility by increasing the visibility of its scholarship. In addition to enhancing the Network’s reputation, LVHN Scholarly Works has been instrumental in saving time and easing workflows for several of its residency programs as well as for ACGME accreditation, and has even contributed to filling in missing pieces of institutional history. As the initiative moves forward, the library continues to look for ways to further increase the visibility of LVHN’s scholarship and help to solve other challenges.
Over the course of this webinar, Kris Petre, Senior Medical Librarian at LVHN, provides an overview of their repository initiative and its importance to LVHN, and then dives into some of the specific projects that they have undertaken, including the results of those projects to date
Asymptotic Stability for a Class of Metriplectic Systems
Using the framework of metriplectic systems on we will describe a
constructive geometric method to add a dissipation term to a Hamilton-Poisson
system such that any solution starting in a neighborhood of a nonlinear stable
equilibrium converges towards a certain invariant set. The dissipation term
depends only on the Hamiltonian function and the Casimir functions
Medicine in the Americas
Medicine in the Americas is a freely available, searchable collection of historical medical Americana. The collection is part of the Digital Collections repository at the National Library of Medicine’s online digital archives. This review discusses the contents, searching functions, and additional features available in the collection
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