SEPARATION OF FOREGROUND RADIATION FROM COSMIC MICROWAVE BACKGROUND ANISOTROPY USING MULTIFREQUENCY MEASUREMENTS

被引:84
作者
BRANDT, WN [1 ]
LAWRENCE, CR [1 ]
READHEAD, ACS [1 ]
PAKIANATHAN, JN [1 ]
FIOLA, TM [1 ]
机构
[1] CALTECH,OWENS VALLEY RADIO OBSERV 105-24,PASADENA,CA 91125
关键词
COSMIC MICROWAVE BACKGROUND; RADIO CONTINUUM; GENERAL;
D O I
10.1086/173867
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Future measurements of the isotropy of the cosmic microwave background radiation (CBR) will be limited by confusing foreground radiation. We examine the extent to which galactic foregrounds-synchrotron, bremsstrahlung, and dust radiation-can be identified and removed using multifrequency data. We discuss the capabilities and limitations of this approach and investigate its effectiveness for various choices of observing frequencies using simulations over 10-degrees x 10-degrees patches of sky with 1-degree resolution. At this resolution galactic fluctuations are at a minimum just below 100 GHz. In our simulations, observations covering two or three octaves in frequency well below or well above this minimum region perform much better than those in the minimum region and allow accurate subtraction of foregrounds if the measurement noise is sufficiently low. We are thus optimistic that Galactic foreground fluctuations can be distinguished from CBR fluctuations in multifrequency data on 1-degree scales. The required noise level depends in a highly nonlinear way on the frequencies observed, the model used to fit the various signal components, and on (unknown) details of the foreground emissions and CBR anisotropy. Even in favorable cases, however, the required noise level is much below any achieved to date. Separation of the CBR from foregrounds required at least three free parameters in the simulations, thus observations at a minimum of four frequencies are required for our method. We also discuss the usefulness of measurements of foreground components made at frequencies where those foregrounds are strong, and we show that even if the functional form of the spectrum of the foregrounds is perfectly known, the absolute error that can be tolerated in measurements at other frequencies is comparable to the error that can be tolerated where the CBR is measured. Thus there is no easy way to subtract confusing foregrounds directly.
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页码:1 / 21
页数:21
相关论文
共 44 条
  • [1] A SEARCH FOR ANISOTROPY IN THE COSMIC MICROWAVE BACKGROUND ON INTERMEDIATE ANGULAR SCALES
    ALSOP, DC
    CHENG, ES
    CLAPP, AC
    COTTINGHAM, DA
    FISCHER, ML
    GUNDERSEN, JO
    KREYSA, E
    LANGE, AE
    LUBIN, PM
    MEINHOLD, PR
    RICHARDS, PL
    SMOOT, GF
    [J]. ASTROPHYSICAL JOURNAL, 1992, 395 (02) : 317 - 325
  • [2] GALACTIC DUST EMISSION AND THE COSMIC MICROWAVE BACKGROUND
    BANDAY, AJ
    WOLFENDALE, AW
    [J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1991, 252 (03) : 462 - 472
  • [3] FLUCTUATIONS IN THE GALACTIC SYNCHROTRON RADIATION .1. IMPLICATIONS FOR SEARCHES FOR FLUCTUATIONS OF COSMOLOGICAL ORIGIN
    BANDAY, AJ
    WOLFENDALE, AW
    [J]. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1991, 248 (04) : 705 - 714
  • [4] COSMIC-RAYS AND COSMOLOGICAL MICROWAVE BACKGROUND FLUCTUATIONS
    BANDAY, AJ
    GILER, M
    SZABELSKA, B
    SZABELSKI, J
    WOLFENDALE, AW
    [J]. ASTROPHYSICAL JOURNAL, 1991, 375 (02) : 432 - 438
  • [5] BANDAY AJ, 1990, MON NOT R ASTRON SOC, V245, P182
  • [6] Beichman C.A., 1988, IRAS CATALOGS ATLASE
  • [7] PRELIMINARY SEPARATION OF GALACTIC AND COSMIC MICROWAVE EMISSION FOR THE COBE DIFFERENTIAL MICROWAVE RADIOMETER
    BENNETT, CL
    SMOOT, GF
    HINSHAW, G
    WRIGHT, EL
    KOGUT, A
    DEAMICI, G
    MEYER, SS
    WEISS, R
    WILKINSON, DT
    GULKIS, S
    JANSSEN, M
    BOGGESS, NW
    CHENG, ES
    HAUSER, MG
    KELSALL, T
    MATHER, JC
    MOSELEY, SH
    MURDOCK, TL
    SILVERBERG, RF
    [J]. ASTROPHYSICAL JOURNAL, 1992, 396 (01) : L7 - &
  • [8] BERKHUIJSEN EM, 1972, A AS, V15, P252
  • [9] BOND JR, TRENDS ASTROPARTICLE
  • [10] LIMITS ON GAUSSIAN FLUCTUATIONS IN THE COSMIC MICROWAVE BACKGROUND AT 19.2-GHZ
    BOUGHN, SP
    CHENG, ES
    COTTINGHAM, DA
    FIXSEN, DJ
    [J]. ASTROPHYSICAL JOURNAL, 1992, 391 (02) : L49 - L52