The diffuse radio emission from the Coma cluster at 2.675 GHz and 4.85 GHz

Details The diffuse radio emission from the Coma cluster at 2.675 GHz and 4.85 GHz The diffuse radio emission from the Coma cluster at 2.675 GHz and 4.85 GHz

2002-10-07

arxiv.org/abs/astro-ph/0210147v3

Astron.Astrophys.397:53-62,2003

Astronomy and Astrophysics

Astrophysics

10 pages with 9 PostScript figures. Accepted for publication in A&A, latest revision includes minor changes at page proof corr

Scientific paper

10.1051/0004-6361:20021474

We present new measurements of the diffuse radio halo emission from the Coma cluster of galaxies at 2.675 GHz and 4.85 GHz using the Effelsberg 100--m telescope. After correction for the contribution from point sources we derive the integrated flux densities for the halo source (Coma C), $S_{2.675 GHz}=(107\pm 28)mJy$ and $S_{4.85 GHz}=(26\pm 12)mJy$. These values verify the strong steepening of the radio spectrum of Coma C at high frequencies. Its extent strongly depends on frequency, at 4.85 GHz it is only marginally visible. The measurement at 4.85 GHz is the first flux density determination for Coma C at this high frequency. In order to quantify the spectral steepening we compare the expectations for the spectrum of Coma C with the observations, resorting to basic models for radio halo formation. The in--situ acceleration model provides the best fit to the data. From equipartition assumptions we estimate a magnetic field strength $B_{eq}=0.57 (1+k)^{0.26}\mu G$ in the intracluster medium of Coma, where k is the energy ratio of the positively and negatively charged particles. As a by--product of the 2.675 GHz observation we present a new flux density for the diffuse emission of the extended source 1253+275 ($S_{2.675GHz}=112\pm 10$). This measurement provides a smaller error range for the power--law fit to the spectrum ($\alpha=1.18\pm 0.02$) compared to previous investigations and yields an equipartition magnetic field strength of $B_{eq}=0.56 (1+k)^{0.24}\mu G$.

Affiliated with

Also associated with

No associations

Rating

The diffuse radio emission from the Coma cluster at 2.675 GHz and 4.85 GHz does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The diffuse radio emission from the Coma cluster at 2.675 GHz and 4.85 GHz, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The diffuse radio emission from the Coma cluster at 2.675 GHz and 4.85 GHz will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-439449