A determination of the spectral index of galactic synchrotron emission in the 1-10 GHz range

被引：116

作者：

Platania, P

Bensadoun, M

Bersanelli, M

De Amici, G

Kogut, A

Levin, S

Maino, D

Smoot, GF

机构：

[1] CNR, Ist Fis Cosm, I-20133 Milan, Italy

[2] Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA

[3] Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA

[4] TRW Co Inc, Space & Technol Div, Redondo Beach, CA 90278 USA

[5] NASA, Goddard Space Flight Ctr, Hughes STX, Greenbelt, MD 20771 USA

[6] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA

[7] SISSA, Sch Adv Int Studies, I-34014 Trieste, Italy

来源：

ASTROPHYSICAL JOURNAL | 1998年 / 505卷 / 02期

关键词：

diffuse radiation; radiation mechanisms : nonthermal;

D O I：

10.1086/306175

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We present an analysis of simultaneous multifrequency measurements of the Galactic emission in the 1-10 GHz range with 18 degrees angular resolution taken from a high-altitude site. Our data yield a determination of the synchrotron spectral index between 1.4 and 7.5 GHz of beta(syn) = 2.81 +/- 0.16. Combining our data with maps made by Haslam et al. and Reich & Reich, we find beta(syn) = 2.76 +/- 0.11 in the 0.4-7.5 GHz range. These results are in agreement with the few previously published measurements. The variation of beta(syn) with frequency based on our results and compared with other data found in the literature suggests a steepening of the synchrotron spectrum toward high frequencies, as expected from theory because of the steepening of the parent cosmic-ray electron energy spectrum. Comparison between the Haslam data and the 19 GHz map of Cottingham also indicates a spatial variation of the spectral index on large angular scales. Additional high-quality data are necessary to provide a serious study of these effects.

引用

页码：473 / 483

页数：11

共 27 条

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