2007A&A...470..875P


Query : 2007A&A...470..875P

2007A&A...470..875P - Astronomy and Astrophysics, volume 470, 875-888 (2007/8-2)

In search of dying radio sources in the local universe.

PARMA P., MURGIA M., DE RUITER H.R., FANTI R., MACK K.-H. and GOVONI F.

Abstract (from CDS):

Up till now very few dying sources were known, presumably because the dying phase is short at centimeter wavelengths. We therefore have tried to improve the statistics on sources that have ceased to be active, or are intermittently active. The latter sources would partly consist of a fossil radio plasma left over from an earlier phase of activity, plus a recently restarted core and radio jets. Improving the statistics of dying sources will give us a better handle on the evolution of radio sources, in particular the frequency and time scales of radio activity. We have used the WENSS and NVSS surveys, in order to find sources with steep spectral indices, associated with nearby elliptical galaxies. In the cross correlation we presently used only unresolved sources, with flux densities at 1.4GHz larger than 10mJy. The eleven candidates thus obtained were observed with the VLA in various configurations, in order to confirm the steepness of the spectra, and to check whether active structures like flat-spectrum cores and jets are present, perhaps at low levels. We estimated the duration of the active and relic phases by modelling the integrated radio spectra using the standard models of spectral evolution. We have found six dying sources and three restarted sources, while the remaining two candidates remain unresolved also with the new VLA data and may be Compact Steep Spectrum sources, with an unusually steep spectrum. The typical age of the active phase, as derived by spectral fits, is in the range 107-108 years. For our sample of dying sources, the age of the relic phase is on average shorter by an order of magnitude than the active phase.

Abstract Copyright:

Journal keyword(s): radio continuum: galaxies - galaxies: active

CDS comments: Paragraph 5.6 cluster Zw 1328.9+6518 not identified.

Simbad objects: 20

goto Full paper

goto View the references in ADS

Number of rows : 20
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 ACO 580 ClG 07 25 57.08 +41 23 05.1           ~ 23 0
2 2MASX J07255712+4123069 BiC 07 25 57.1387605696 +41 23 06.612668628           ~ 16 1
3 2MASX J08400233+2949027 Sy2 08 40 02.336 +29 49 02.73   20.00 19.62     ~ 176 1
4 6C 095153+603742 BiC 09 55 29.882 +60 23 17.33           ~ 12 1
5 7C 1023+2959 BiC 10 26 11.8873799472 +29 43 45.409277172           ~ 6 0
6 7C 112733.70+492748.00 BiC 11 30 18.3213900000 +49 11 15.948343068           ~ 13 1
7 7C 115000.59+374925.00 BiC 11 52 36.456 +37 32 43.76           ~ 9 2
8 NSC J115245+373321 ClG 11 52 45.27 +37 33 21.1           ~ 2 0
9 NSC J125947+312215 ClG 12 59 47.05 +31 22 14.8           ~ 2 0
10 FIRST J125951.9+312105 rG 12 59 51.9907825752 +31 21 06.217515216           ~ 18 1
11 2MASX J13300274+6504591 BiC 13 30 02.775 +65 04 59.07           ~ 9 0
12 NSC J141045+461634 ClG 14 10 45.82 +46 16 33.9           ~ 2 0
13 6C 140851+462954 BiC 14 10 48.1951368096 +46 15 57.675281652           ~ 11 1
14 6C 143801+372019 BLL 14 40 03.4477832064 +37 07 27.399073800     18.01     ~ 22 1
15 LEDA 140448 BiC 14 59 43.238 +49 47 15.71           ~ 10 1
16 ACO 2011 ClG 14 59 50 +49 45.1           ~ 9 0
17 UGC 9799 Sy2 15 16 44.4893939136 +07 01 17.825410740   15.19 14.17     ~ 437 3
18 3C 338.0 QSO 16 28 38.24470063 +39 33 04.2335319   12.78 11.78     ~ 742 5
19 NGC 7618 GiG 23 19 47.2346536992 +42 51 09.228387528   14.3       ~ 59 2
20 NVSS J231947+425110 Rad 23 19 47.90 +42 51 10.8           ~ 4 1

To bookmark this query, right click on this link: simbad:objects in 2007A&A...470..875P and select 'bookmark this link' or equivalent in the popup menu


2023.03.27-06:20:48

© Université de Strasbourg/CNRS

    • Contact