Brightness Temperature Maps Research Articles

The Galactic Continuum Spurs and Neutral Hydrogen

So far no association has been found between the features of the galactic continuum radiation known as the spurs and the distribution of neutral hydrogen. McGee, Murray and Milton1 give contour maps of the peak brightness temperature of profiles of low velocity neutral hydrogen, and if the position of the steep outer gradient of the continuum radiation from the North Polar Spur, obtained from the best data at present available2–4, is plotted on these maps (Fig. 1), a correlation is immediately apparent. The line of outer gradient coincides with a spur feature in the neutral hydrogen distribution. Also plotted on Fig. 1 is the outer gradient of the continuum ridge at +10° declination, taken from ref. 4. The ridges P and U from ref. 5 are included up to the limit of that survey at R.A. = 16 h. All these ridges are in close coincidence with similar hydrogen features. A section through the neutral hydrogen and continuum distributions for the North Polar Spur edge at bII = +45° is shown in Fig. 2.

Structure of the Jovian Disk in the ν_{2}-BAND of Ammonia at 100000 Å

view Abstract Citations (11) References (54) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Structure of the Jovian Disk in the ν2-BAND of Ammonia at 100000 Å Wildey, Robert L. Abstract New brightness-temperature maps have been obtained for the thermal radiation of Jupiter admitted through the 8-l4-Jh window of the Earth's atmosphere. Maps obtained throughout an apparition ex- hibit real structure other than simple limb darkening and show a variable degree of correlation with the structure of the visible image. Most notable features of the maps are the following: On March 14/15, 1965, there is a very high-albedo south-preceding sector of the disk, not banded entirely across the disk but wide in latitude, which is minimally 5° colder than other regions of comparable limb proximity; the Great Red Spot is 2° colder; a large, dark northern cap is 1°-2° colder. On March 4/5 a dark north- ern cap appears anomalously cool only near sunrise and sunset. The visible- and photographic-infrared cloud layer lies at great optical depth in the ~2 rotational band of NH3 for all wavelengths of photometer response. If, as seems very likely, the emergent specific in- tensity is largely determined by upper atmospheric layers, where the ammonia frost point closely follows the local temperature, then the sharp dependence of the vapor pressure of solid ammonia on temperature confines the emitting molecules to a fairly narrow range in temperature. This militates against the presence of significant contrast, even very noticeable limb darkening, and suggests vertical activity of such a magnitude that quasi-static plane-parallel model atmospheres may be inadequate for providing theoretical consistency among all the observations Publication: The Astrophysical Journal Pub Date: November 1968 DOI: 10.1086/149795 Bibcode: 1968ApJ...154..761W full text sources ADS | Related Materials (1) Erratum: 1971ApJ...164..395W

On the interpretation of thermal emission maps of Jupiter

In a paper in this issue of the Journal, Wildey et al. [1965] have presented the results of recent efforts to contour the isophotes over the disk of Jupiter for the thermal emission in the heterochromatic-magnitude band extending from 8 to 14 microns. Such brightness temperature maps represent an important constraint on Jovian model atmospheres in which over-all processes of energy transport and balance are considered. Because of the limitations on the accuracy of the present mapping procedures, important discrimination must be made between structural features of maps which are obviously noise and those which are good candidates for the extraction of theoretical implications. The peculiar nature of the noise warrants an elaboration of this discriminatory procedure.

Solar Observations at 3.2 MM.

view Abstract Citations (27) References (7) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Solar Observations at 3.2 MM. Simon, Michal Abstract We discuss the extensive observations of the Sun at 3.2-mm wavelength carried out during the summer of 1964 with a radio telescope of 3' beam width. An average brightness temperature of 6402 + 215 K was measured at the center of the solar disk. No consistent limb brightening was observed. Brightnesstemperature maps were made and are correlated with Ha photographs and magnetograms. Regions of enhanced 3 2-mm emission are shown to correlate well with Ha-active regions and regions of strong magnetic fields. Particularly high enhancements were observed in regions that later flared. One flare was observed but not from its beginning. No bursts were detected. Publication: The Astrophysical Journal Pub Date: May 1965 DOI: 10.1086/148239 Bibcode: 1965ApJ...141.1513S full text sources ADS |

The influence of natural noise upon antenna system performance

The effects of natural radio noise upon the performance of ground antenna systems are examined. After the spatial and spectral properties of some major sources of radio noise are described, the results of a comprehensive program of machine computation of antenna temperature are analyzed. These results and those of a recently completed noise measurement program are used to evaluate the carrier-to-noise ratio (c/n) at ground receiving antennas tracking a space probe and a medium-altitude satellite. From published maps of galactic brightness temperature, from flux-density spectra developed with data on thermal and nonthermal radiation from the planets, and from recent models of the solar atmosphere, antenna temperatures have been computed for apertures ranging from 30 to 1,000 feet at frequencies between 60 and 30,000 mc (megacycles).