E-resources
-
Macario, G.; Venturi, T.; Intema, H. T.; Dallacasa, D.; Brunetti, G.; Cassano, R.; Giacintucci, S.; Ferrari, C.; Ishwara-Chandra, C. H.; Athreya, R.
Astronomy and astrophysics (Berlin), 03/2013, Volume: 551Journal Article
Aims. We present new high-sensitivity 153 MHz Giant Meterwave Radio Telescope follow-up observations of the diffuse steep-spectrum cluster radio sources in the galaxy clusters Abell 521, Abell 697, and Abell 1682. Abell 521 hosts a relic, and together with Abell 697 it also hosts a giant very steep-spectrum radio halo. Abell 1682 is a more complex system with candidate steep spectrum diffuse emission. Methods. We imaged the diffuse radio emission in these clusters at 153 MHz, and provided flux density measurements of all sources at this frequency. Our new flux density measurements, coupled with the existing data at higher frequencies, allowed us to study the total spectrum of the halos and relic over at least one order of magnitude in frequency. Results. Our images confirm the very steep “diffuse component” in Abell 1682. We found that the spectrum of the relic in Abell 521 can be fitted by a single power-law with α = 1.45 ± 0.02 from 153 MHz to 5 GHz. Moreover, we confirm that the halos in Abell 521 and Abell 697 have a very steep spectrum , with α = 1.8 − 1.9 and α = 1.52 ± 0.05, respectively. Even including of the 153 MHz flux density information, it is impossible to distinguish between power-law and curved spectra, as derived from homogeneous turbulent re-acceleration. The latter are favoured on the basis of simple energetic arguments, and we expect that LOFAR will finally unveil the spectral shape of radio halos below 100 MHz, thus providing clues on their origin.
Author
Shelf entry
Permalink
- URL:
Impact factor
Access to the JCR database is permitted only to users from Slovenia. Your current IP address is not on the list of IP addresses with access permission, and authentication with the relevant AAI accout is required.
Year | Impact factor | Edition | Category | Classification | ||||
---|---|---|---|---|---|---|---|---|
JCR | SNIP | JCR | SNIP | JCR | SNIP | JCR | SNIP |
Select the library membership card:
If the library membership card is not in the list,
add a new one.
DRS, in which the journal is indexed
Database name | Field | Year |
---|
Links to authors' personal bibliographies | Links to information on researchers in the SICRIS system |
---|
Source: Personal bibliographies
and: SICRIS
The material is available in full text. If you wish to order the material anyway, click the Continue button.