67,781 research outputs found
Options for organization and operation of space applications transfer centers
The benefits of developing regional facilities for transfer of NASA developed technology are discussed. These centers are designed to inform, persuade, and serve users. Included will be equipment for applications and demonstrations of the processes, a library, training facilities, and meeting rooms. The staff will include experts in the various techniques, as well as personnel involved in finding and persuading potential users
Kinematics of the Broad Line Region in M81
A new model is presented which explains the origin of the broad emission
lines observed in the LINER/Seyfert nucleus of M81 in terms of a steady state
spherically symmetric inflow, amounting to 1 x 10^-5 Msun/yr, which is
sufficient to explain the luminosity of the AGN. The emitting volume has an
outer radius of ~1 pc, making it the largest broad line region yet to be
measured, and it contains a total mass of ~ 5 x 10^-2 Msun of dense, ~ 10^8
cm^-3, ionized gas, leading to a very low filling factor of ~ 5 x 10^-9. The
fact that the BLR in M81 is so large may explain why the AGN is unable to
sustain the ionization seen there. Thus, the AGN in M81 is not simply a scaled
down quasar.Comment: Accepted for Publication in ApJ 7/21/0
Long-range triplet proximity effect in multiply connected ferromagnet-superconductor hybrids
Applying the linearized Usadel equations, we consider the nucleation of
superconductivity in multiply connected mesoscopic superconductor/ferromagnet
(S/F) hybrids such as a thin superconducting ring on a ferromagnet with a
uniform in-plane magnetization M and a spin-active S/F interface. We
demonstrate that the exchange field in F provokes a switching between
superconducting states with different vorticities which may increase the
critical temperature ( Tc ) of the superconductor in a magnetic field. We study
the interplay between oscillations in Tc due to the Little--Parks effect and
oscillations in Tc induced by the exchange field. Furthermore, we analyse the
influence of long-range spin-triplet correlations on the switching between
different vorticities.Comment: 11 pages, 7 figure
Spectroastrometry of rotating gas disks for the detection of supermassive black holes in galactic nuclei. III. CRIRES observations of the Circinus galaxy
We present new CRIRES spectroscopic observations of BrGamma in the nuclear
region of the Circinus galaxy, obtained with the aim of measuring the black
hole (BH) mass with the spectroastrometric technique. The Circinus galaxy is an
ideal benchmark for the spectroastrometric technique given its proximity and
secure BH measurement obtained with the observation of its nuclear H2O maser
disk. The kinematical data have been analyzed both with the classical method
based on the analysis of the rotation curves and with the new method developed
by us and based on spectroastrometry. The classical method indicates that the
gas disk rotates in the gravitational potential of an extended stellar mass
distribution and a spatially unresolved mass of (1.7 +- 0.2) 10^7 Msun,
concentrated within r < 7 pc. The new method is capable of probing gas rotation
at scales which are a factor ~3.5 smaller than those probed by the rotation
curve analysis. The dynamical mass spatially unresolved with the
spectroastrometric method is a factor ~2 smaller, 7.9 (+1.4 -1.1) 10^6 Msun
indicating that spectroastrometry has been able to spatially resolve the
nuclear mass distribution down to 2 pc scales. This unresolved mass is still a
factor ~4.5 larger than the BH mass measurement obtained with the H2O maser
emission indicating that it has not been possible to resolve the sphere of
influence of the BH. Based on literature data, this spatially unresolved
dynamical mass distribution is likely dominated by molecular gas and it has
been tentatively identified with the circum-nuclear torus which prevents a
direct view of the central BH in Circinus. This mass distribution, with a size
of ~2pc, is similar in shape to that of the star cluster of the Milky Way
suggesting that a molecular torus, forming stars at a high rate, might be the
earlier evolutionary stage of the nuclear star clusters which are common in
late type spirals.Comment: A&A in press. We wish to honor the memory of our great friend and
colleague David Axon. He will be greatly missed by all of us. arXiv admin
note: text overlap with arXiv:1110.093
Children's suggestibility in relation to their understanding about sources of knowledge
In the experiments reported here, children chose either to maintain their initial belief about an object's identity or to accept the experimenter's contradicting suggestion. Both 3– to 4–year–olds and 4– to 5–year–olds were good at accepting the suggestion only when the experimenter was better informed than they were (implicit source monitoring). They were less accurate at recalling both their own and the experimenter's information access (explicit recall of experience), though they performed well above chance. Children were least accurate at reporting whether their final belief was based on what they were told or on what they experienced directly (explicit source monitoring). Contrasting results emerged when children decided between contradictory suggestions from two differentially informed adults: Three– to 4–year–olds were more accurate at reporting the knowledge source of the adult they believed than at deciding which suggestion was reliable. Decision making in this observation task may require reflective understanding akin to that required for explicit source judgments when the child participates in the task
Mars Mariner 4 - Identification of some Martian surface features
Martian surface features identified from photographs by Mariner 4 space prob
Full major-shell calculation for states that were degenerate in a single-j-shell calculation
A full fp calculation is performed for states which were degenerate in a
single-j-shell calculation in which isospin-zero two-body matrix elements were
set to zero energy. Most of the splitting in a complete shell calculation (but
not all) comes from the T=0 part of the interaction.Comment: 5 pages, RevTeX4. Submitted to Physical Review
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