582 research outputs found
High angular resolution cosmic X-ray astronomy observations in the energy range 0.15-2 keV and XUV observations of nearby stars from an attitude controlled rocket
The construction of a two dimensional focusing Wolter Type I mirror system for X-ray and XUV astronomical observations from an Astrobee F sounding rocket is described. The mirror design goal will have a one degree field, a 20-arc seconds resolution, an effective area of about 50 sq cm at 1 keV and 10 sq cm at 0.25 keV on axis. A star camera provides aspect data to about 15-arc seconds. Two detectors are placed at the focus with an interchange mechanism to allow a detector change during flight. The following specific developments are reported: (1) position sensitive proportional counter development; (2) channel plate multiplier development; (3) telescope mirror development and payload structure; (4) Australian rocket flight results; (5) Comet Kohoutek He I observation; and (6) Vela, Puppis A, and Gem-Mon bright patch observations
Support of selected X-ray studies to be performed using data from the Uhuru (SAS-A) satellite
A new measurement of the diffuse X-ray emission sets more stringent upper limits on the fluctuations of the background and on the number counts of X-ray sources with absolute value of b 20 deg than previous measurements. A random sample of background data from the Uhuru satellite gives a relative fluctuation in excess of statistics of 2.0% between 2.4 and 6.9 keV. The hypothesis that the relative fluctuation exceeds 2.9% can be rejected at the 90% confidence level. No discernable energy dependence is evident in the fluctuations in the pulse height data, when separated into three energy channels of nearly equal width from 1.8 to 10.0 keV. The probability distribution of fluctuations was convolved with the photon noise and cosmic ray background deviation (obtained from the earth-viewing data) to yield the differential source count distribution for high latitude sources. Results imply that a maximum of 160 sources could be between 1.7 and 5.1 x 10 to the -11 power ergs/sq cm/sec (1-3 Uhuru counts)
Surface brightness measurements of supernova remanants in the energy band 0.15 - 4 keV and an XUV survey from an altitude controlled rocket
Reports are presented concerning the flight of Aerobee 170, 13.063 UG. The papers presented include: soft X-rays for Cygnus X-1 and Cygnus X-2; X-ray spectrum of the entire Cygnus loop; X-ray surface brightness of the Cygnus loop; and observations of He II 304 A and He I 584 a nightglow
Solar X-rays scattered by Venus, Mars and the Moon
Scattering process of solar X rays with photoionization fluorescence by planetary atmosphere
Observation of mode locking and ultrashort optical pulses induced by antisotropic molecular liquids
Mode locking and ultrashort pulses have been produced in a giant-pulse ruby laser with heated nitrobenzene (T > 110°C) or -chloronaphthalene (T > 62°C) inside the optical resonator. 10^(–11)-sec pulses were observed with the two-photon fluorescence technique
Parsec-scale X-ray Flows in High-mass Star-forming Regions
The Chandra X-ray Observatory is providing remarkable new views of massive
star-forming regions, revealing all stages in the life cycle of high-mass stars
and their effects on their surroundings. We present a Chandra tour of several
high-mass star-forming regions, highlighting physical processes that
characterize the life of a cluster of high-mass stars, from deeply-embedded
cores too young to have established an HII region to superbubbles so large that
they shape our views of galaxies. Along the way we see that X-ray observations
reveal hundreds of stellar sources powering great HII region complexes,
suffused by both hard and soft diffuse X-ray structures caused by fast O-star
winds thermalized in wind-wind collisions or by termination shocks against the
surrounding media. Finally, we examine the effects of the deaths of high-mass
stars that remained close to their birthplaces, exploding as supernovae within
the superbubbles that these clusters created. We present new X-ray results on
W51 IRS2E and 30 Doradus and we introduce new data on Trumpler 14 in Carina and
the W3 HII region complexes W3 Main and W3(OH).Comment: 6 pages, 3 figures, to appear in the proceedings of IAU Symposium
227,"Massive Star Birth - A Crossroads of Astrophysics," eds. R. Cesaroni, E.
Churchwell, M. Felli, and C.M. Walmsle
- …