Title
Limits to Cosmic Background Radiation Fluctuations at 8.44 GHz Between Angular Scales 10″ and 200″
Document Type
Article
Publication Date
2-10-1993
Publication Title
Astrophysical Journal
Abstract
We have used the VLA at 8.44 GHz to measure fluctuations in the cosmic background radiation (CBR) from two deep images, each 7′ x 7′ in size. No fluctuations between the angular scales 10″ and 200″ were detected. The most accurate limit (95% confidence) is ΔT/TCBR < 1.9 x 10-5 for 80″ resolution. For random Gaussian fluctuations with coherence angle θc, the limits are ΔT/TCBR < 30 x 10-5 for 22″ < θc < 60″. Outside this range the limits increase to ΔT/TCBR < 5 x 10-5 at θc = 12″ or 100″ and ΔT/TCBR < 10 x 10-5 at θc = 5″ or 120″. Similar limits have been obtained for the circularly and linearly polarized components of the CBR fluctuations. These limits were derived from the residual fluctuations in the images after (1) removing brighter foreground sources (> 14.5 μJy) which covered about 10% of each image; (2) estimating fluctuations of weaker sources by extrapolating the count of dN/dS = 4.6S-2.3 Jy-1 sr-1 to 4 μJy; and (3) determining fluctuations from receiver noise and instrumental errors by comparing the image variances from two independent halves of the data set. All analysis was made on dirty images, in which the statistical properties of instrumental and sky fluctuations are well-defined.
Keywords
Cosmic microwave background, Polarization
Volume
404
Issue
1
First Page
8
Last Page
20
DOI
10.1086/172254
ISSN
0004637X
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Rights
© The Authors
Recommended Citation
Fomalont, Edward B.; Partridge, R. Bruce; Lowenthal, James D.; and Windhorst, Rogier A., "Limits to Cosmic Background Radiation Fluctuations at 8.44 GHz Between Angular Scales 10″ and 200″" (1993). Astronomy: Faculty Publications, Smith College, Northampton, MA.
https://scholarworks.smith.edu/ast_facpubs/72
Comments
Archived as published.