310 research outputs found
Optical frequency waveguide and transmission system Patent
Optical communication system with gas filled waveguide for laser beam transmissio
Laser machining apparatus Patent
Laser machining device with dielectric functioning as beam waveguide for mechanical and medical application
Optical frequency waveguide Patent
Self-generating optical frequency waveguid
Gaia Stellar Kinematics in the Head of the Orion A Cloud: Runaway Stellar Groups and Gravitational Infall
This work extends previous kinematic studies of young stars in the Head of
the Orion A cloud (OMC-1/2/3/4/5). It is based on large samples of infrared,
optical, and X-ray selected pre-main sequence stars with reliable radial
velocities and Gaia-derived parallaxes and proper motions. Stellar kinematic
groups are identified assuming they mimic the motion of their parental gas.
Several groups are found to have peculiar kinematics: the NGC 1977 cluster and
two stellar groups in the Extended Orion Nebula (EON) cavity are caught in the
act of departing their birthplaces. The abnormal motion of NGC 1977 may have
been caused by a global hierarchical cloud collapse, feedback by massive Ori
OB1ab stars, supersonic turbulence, cloud-cloud collision, and/or slingshot
effect; the former two models are favored by us. EON groups might have
inherited anomalous motions of their parental cloudlets due to small-scale
`rocket effects' from nearby OB stars. We also identify sparse stellar groups
to the east and west of Orion A that are drifting from the central region,
possibly a slowly expanding halo of the Orion Nebula Cluster. We confirm
previously reported findings of varying line-of-sight distances to different
parts of the cloud's Head with associated differences in gas velocity.
Three-dimensional movies of star kinematics show contraction of the groups of
stars in OMC-1 and global contraction of OMC-123 stars. Overall, the Head of
Orion A region exhibits complex motions consistent with theoretical models
involving hierarchical gravitational collapse in (possibly turbulent) clouds
with OB stellar feedback.Comment: Accepted for publication in MNRAS. 26 pages, 13 figures. The two 3-D
stellar kinematic movies, aimed as Supplementary Materials, can be found on
YouTube at: https://youtu.be/B4GHCVvCYfo (`restricted' sample) and
https://youtu.be/6fUu8sP0QFI (`full' sample
Detection of x-rays from galaxy groups associated with the gravitationally lensed systems PG 1115+080 and B1422+231
Gravitational lenses that produce multiple images of background quasars can
be an invaluable cosmological tool. Deriving cosmological parameters, however,
requires modeling the potential of the lens itself. It has been estimated that
up to a quarter of lensing galaxies are associated with a group or cluster
which perturbs the gravitational potential. Detection of X-ray emission from
the group or cluster can be used to better model the lens. We report on the
first detection in X-rays of the group associated with the lensing system PG
1115+080 and the first X-ray image of the group associated with the system
B1422+231. We find a temperature and rest-frame luminosity of 0.8 +/- 0.1 keV
and 7 +/- 2 x 10^{42} ergs/s for PG 1115+080 and 1.0 +infty/-0.3 keV and 8 +/-
3 x 10^{42} ergs/s for B1422+231. We compare the spatial and spectral
characteristics of the X-ray emission to the properties of the group galaxies,
to lens models, and to the general properties of groups at lower redshift.Comment: Accepted for publication in ApJ. 17 pages, 5 figures. Minor changes
to tex
A new class of trapped light filaments
New class light filament identified in Raman radiation of intense ruby laser bea
Chandra Observations of "The Antennae" Galaxies (NGC 4038/39)
We report the results of a deep Chandra ACIS pointing at the merging system
NGC 4038/39. We detect an extraordinarily luminous population of X-ray sources,
with luminosity well above that of XRBs in M31 and the Milky Way. If these
sources are unbeamed XRBs, our observations may point to them being 10-100Mo
black hole counterparts. We detect an X-ray bright hot ISM, with features
including bright superbubbles associated with the actively star-forming knots,
regions where hot and warm (H) ISM intermingle, and a large-scale
outflow.Comment: 7 pages, 10 figures, Accepted for publication in Ap
The cosmic X-ray experiment aboard HEAO-1
The HEAO-1 A-2 experiment, designed to study the large scale structure of the galaxy and the universe at X-ray energies is described. The instrument consists of six gas proportional counters of three types nominally covering the energy ranges of 0.15-3 keV, 1.2-20 keV, and 2.5-60 keV. The two low energy detectors have about 400 sq cm open area each while the four others have about 800 sq cm each. Dual field of view collimators allow the unambiguous determination of instrument internal background and diffuse X-ray brightness. Instrument characteristics and early performance are discussed
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