Quick Search:

uzh logo
Browse by:

Zurich Open Repository and Archive

Maintenance: Tuesday, 5.7.2016, 07:00-08:00

Maintenance work on ZORA and JDB on Tuesday, 5th July, 07h00-08h00. During this time there will be a brief unavailability for about 1 hour. Please be patient.

Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-55360

de Paolis, F; Gurzadyan, V G; Ingrosso, G; Jetzer, P; Nucita, A A; Qadir, A; Vetrugno, D; Kashin, A L; Khachatryan, H G; Mirzoyan, S (2011). Possible detection of the M 31 rotation in WMAP data. Astronomy & Astrophysics, 534:L8.

Accepted Version
View at publisher


Data on the cosmic microwave background (CMB) radiation by the Wilkinson Microwave Anisotropy Probe (WMAP) had a profound impact on the understanding of a variety of physical processes in the early phases of the Universe and on the estimation of the cosmological parameters. Here, the 7-year WMAP data are used to trace the disk and the halo of the nearby giant spiral galaxy M 31. We analyzed the temperature excess in three WMAP bands (W, V, and Q) by dividing the region of the sky around M 31 into several concentric circular areas. An asymmetry in the mean microwave temperature in the M 31 disk along the direction of the M 31 rotation is observed with a temperature contrast up to ≃ 130 μK/pixel. We also find a temperature asymmetry in the M 31 halo, which is much weaker than for the disk, up to a galactocentric distance of about 10° (≃ 120 kpc) with a peak temperature contrast of about 40 μK/pixel. We studied the robustness of these possible detections by considering 500 random control fields in the real WMAP maps and simulating 500 sky maps from the best-fitted cosmological parameters. By comparing the obtained temperature contrast profiles with the real ones towards the M 31 galaxy, we find that the temperature asymmetry in the M 31 disk is fairly robust, while the effect in the halo is weaker. Although the confidence level of the signal is not high, if estimated purely statistically, which could be expected due to the weakness of the effect, the geometrical structure of the temperature asymmetry points towards a definite effect modulated by the rotation of the M 31 halo. This result might open a new way to probe these relatively less studied galactic objects using high-accuracy CMB measurements, such as those with the Planck satellite or planned balloon-based experiments, which could prove or disprove our conclusions.




40 downloads since deposited on 19 Feb 2012
11 downloads since 12 months

Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Institute for Computational Science
Dewey Decimal Classification:530 Physics
Date:October 2011
Deposited On:19 Feb 2012 16:11
Last Modified:05 Apr 2016 15:23
Publisher:EDP Sciences
ISSN:0004-6361 (P) 1432-0746 (E)
Publisher DOI:10.1051/0004-6361/201117846
Related URLs:http://arxiv.org/abs/1109.6290

Users (please log in): suggest update or correction for this item

Repository Staff Only: item control page