scholarly journals ALEXIS Observations of the Diffuse Cosmic Background in the Extreme Ultraviolet

1996 ◽  
Vol 152 ◽  
pp. 283-287
Author(s):  
Barham W. Smith ◽  
T.E. Pfafman ◽  
J.J. Bloch ◽  
B.C. Edwards
Keyword(s):  
Extreme Ultraviolet ◽  
Narrow Band ◽  
Satellite Observations ◽  
Background Signal ◽  
Preliminary Results ◽  
Upper Limit ◽  
Cosmic Background ◽  
Clear Signal ◽  
Diffuse Background ◽  
Sky Monitor

Abstract.We present preliminary results of ALEXIS satellite observations of the extreme ultraviolet diffuse sky. ALEXIS was designed to be a half-sky monitor in three narrow wavelength bands between 13.0 and 19.0 nm. In our band centered at 172 Å we find a clear signal from the diffuse sky that is about 20 counts per second above the signal when looking at the dark earth from the same part of an orbit. This difference corresponds to an upper limit on the true cosmic diffuse background signal in this narrow band. When estimates of the geocoronal contributions, both in and out of band, are removed, our upper limit is reduced.

scholarly journals Measurement of the 3 K Cosmic Background Noise in the Far Infrared

1983 ◽  
Vol 104 ◽  
pp. 135-138 ◽  
Author(s):  
G. Dall'oglio ◽  
P. de Bernardis ◽  
S. Masi ◽  
F. Melchiorri
Keyword(s):  
Background Noise ◽  
Quantum Fluctuations ◽  
Far Infrared ◽  
Preliminary Results ◽  
Upper Limit ◽  
Cosmic Background

Quantum fluctuations of the cosmic background have been measured in the 900 to 2000 micron range (H.P.B.W.) by means of a balloon-borne correlator operating between 5 and 150 Hz. Preliminary results indicate an upper limit √<dP2> ≤ 2.1 × 10−17 watt/(cm2 srad Hz)1/2, corresponding to the noise of a blackbody at a temperature T ≤ 3.1 K at 1σ.

scholarly journals 1.3.5 On the Visibility of the Libration Clouds

1976 ◽  
Vol 31 ◽  
pp. 124-129
Author(s):  
S. Röser
Keyword(s):  
Light Intensity ◽  
Satellite Observations ◽  
Libration Points ◽  
Angular Diameter ◽  
Schmidt Telescope ◽  
Zodiacal Light ◽  
Average Brightness ◽  
Upper Limit ◽  
The Earth

In recent years satellite observations of the region of the Earth-Moon libration points L4 and L5 became available, which showed different results. Roach (1975) has measured perturbations of the Zodiacal Light intensity near the libration points L4 and L5 with a photometer on board the OSO-6 satellite. He interpreted the results as counterglow of a cloud of particles, having an angular diameter of 6 degrees and an average brightness of 20 S10v, whereas observations by Burnett et al. (1974) set an upper limit of 10 S10 blue. Earth bound observations made by Bruman (1969) with the 48-inch Palomar Schmidt telescope gave no indication for discrete objects nor for clouds.

Dimensions of Psychopathology in Middle Childhood

1967 ◽  
Vol 21 (3) ◽  
pp. 897-903 ◽  
Author(s):  
Lovick C. Miller
Keyword(s):  
Middle Childhood ◽  
Narrow Band ◽  
Principal Component ◽  
Second Order ◽  
First Order ◽  
Upper Limit ◽  
Number Of Factors

Factorial studies of psychopathology of childhood have revealed from 2 to 14 factors. To be useful, some consensus as to the appropriate number of factors or a means of relating factors must be found. A method is proposed which relates major and minor factors in a meaningful and logical way. 8 principal component factors were extracted and converted to scales from checklist protocols of 263 disturbed male children between 5 and 12 yr. of age. The 8 scales were re-factored to reveal 3 second-order factors. The first-order factors were shown to be psychologically and statistically related to the second-order factors. Second-order factoring appears to provide a method for: relating broad and narrow band factors, permitting the addition of new factors, and setting an upper limit to the number of factors which can be obtained. Implications of the findings for the development of a nosology are considered.

scholarly journals An Instrument to Study the Diffuse EUV Astronomical Background

1996 ◽  
Vol 152 ◽  
pp. 611-616 ◽  
Author(s):  
S. Bowyer ◽  
J. Edelstein ◽  
M. Lampton ◽  
L. Morales ◽  
J. Perez Mercader ◽  
...  
Keyword(s):  
Dark Matter ◽  
Interstellar Medium ◽  
Extreme Ultraviolet ◽  
Unique Line ◽  
Upper Limits ◽  
Diffuse Background ◽  
Source Mechanisms ◽  
New Type

The extreme ultraviolet (EUV) diffuse background is the most poorly known of any of the diffuse astronomical backgrounds. Only upper limits to this flux exist, obtained with spectrometers with very crude (from ≈ 15 to 30 Å) resolution; these limits are generally one to two orders of magnitude larger than the expected sources of cosmic flux. A variety of source mechanisms have been postulated to radiate in this bandpass; the most discussed is the hot phase of the interstellar medium. A speculative possibility is that hot dark matter in the form of massive, radiatively unstable neutrinos in our Galaxy will produce a unique line in this bandpass. We describe an instrument employing a new type of spectrometer which will provide ~5 Å resolution and unprecedented sensitivity for diffuse EUV radiation. The instrument will be carried aboard the newly developed Spanish Minisat satellite.

scholarly journals Searching for emission line and OB stars in Cl 1806-20 using a NIR narrow-band technique

2010 ◽  
Vol 6 (S272) ◽  
pp. 606-607 ◽  
Author(s):  
Michelle L. Edwards ◽  
Reba M. Bandyopadhyay ◽  
Stephen S. Eikenberry ◽  
Valerie J. Mikles ◽  
Dae-Sik Moon
Keyword(s):  
Emission Line ◽  
Massive Star ◽  
Near Infrared ◽  
Narrow Band ◽  
Massive Stars ◽  
Narrow Band Imaging ◽  
Ob Stars ◽  
Luminous Blue Variables ◽  
Upper Limit

AbstractWe survey the environment of Cl 1806-20 using near-infrared narrow-band imaging to search for Brγ features indicative of evolved massive stars. Using this technique, we successfully detect previously identified massive stars in the cluster. We detect no new emission line stars, establishing a firm upper limit on the number of Wolf Rayets and Luminous Blue Variables; however, we do find several candidate OB supergiants, which likely represent the bulk of the heretofore undiscovered massive star population.

Preliminary results of gamma-ray observations from OSO-3

1968 ◽  
Vol 46 (10) ◽  
pp. S414-S418 ◽  
Author(s):  
W. L. Kraushaar ◽  
G. W. Clark ◽  
G. Garmire
Keyword(s):  
Gamma Ray ◽  
Preliminary Results ◽  
Upper Limit ◽  
The Earth ◽  
Gamma Ray Detector

A gamma-ray detector sensitive to energies greater than about 50 MeV has been placed in orbit on board the OSO-3 spacecraft. An analysis of about 28 hours of data yields an upper limit to the solar gamma-ray flux of about 10−4 photons/cm2 s and an upper limit of about 10−4 photons/cm2 s sr to the flux from the sky. The flux from the earth averaged over 4π sr is 0.1 ± 0.03 photons/cm2 s.

Sign in / Sign up

Export Citation Format

Share Document