915 research outputs found
Low-excitation blobs in the Magellanic Clouds
Aims : We study an unknown, or very poorly known, interstellar HII component
in the Magellanic Clouds. This is the first study ever devoted to this class of
objects, which we call Low-excitation blobs (LEBs).
Methods : We used low-dispersion spectroscopy carried out at ESO to obtain
emission line intensities of Ha, Hb, and [OIII] (4959+5007) for 15 objects in
the Large Magellanic Cloud and 14 objects in the Small Magellanic Cloud.
Results are displayed in excitation ([oiii]/Hb ratio) versus Hb luminosity
diagrams.
Results : We show the presence of an LEB component in the Magellanic Clouds
and study its relationship with the already known class of high-excitation
blobs (HEBs). The newly found LEBs are lower excitation counterparts of HEBs
and are powered by less massive exciting stars. Further study of LEBs is
expected to provide new pieces of information for a better understanding the
low mass end of the upper initial mass function in the Magellanic Clouds.Comment: Accepted in A&
STIS spectroscopy of newborn massive stars in SMC N81
Using Hubble Space Telescope observations with STIS, we study the main
exciting stars of N81, a high excitation compact Hii region in the Small
Magellanic Cloud (SMC). These far UV observations are the first spectroscopic
measurements of stars in such a region and reveal features characteristic of an
O6-O8 stellar type. The astonishing weakness of their wind profiles and their
sub-luminosity (up to ~ 2 mag fainter in Mv than the corresponding dwarfs) make
these stars a unique stellar population in the Magellanic Clouds. Our analysis
suggests that they are probably in the Hertzsprung-Russell diagram locus of a
particularly young class of massive stars, the so-called Vz luminosity class,
as they are arriving on the zero age main sequence.Comment: 9 pages, 3 figure
Reservoir Sedimentation Management Using SSIIM-3D Model and GIS
Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv
Statistical Confirmation of a Stellar Upper Mass Limit
We derive the expectation value for the maximum stellar mass (m_max) in an
ensemble of N stars, as a function of the IMF upper-mass cutoff (m_up) and N.
We statistically demonstrate that the upper IMF of the local massive star
census observed thus far in the Milky Way and Magellanic Clouds clearly
exhibits a universal upper mass cutoff around 120 - 200 M_sun for a Salpeter
IMF, although the result is more ambiguous for a steeper IMF.Comment: PDF, 5 pages, 4 figures. Accepted to the Astrophysical Journal
Letter
Entanglement measure for general pure multipartite quantum states
We propose an explicit formula for an entanglement measure of pure
multipartite quantum states, then study a general pure tripartite state in
detail, and at end we give some simple but illustrative examples on four-qubits
and m-qubits states.Comment: 5 page
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