THE SEARCH OF GIANT RADIO GALAXIES AT DECLINATIONS FROM
3 TO 12 DEGREES
Pushchino Radio Astronomy Observatory of Astro Space
CenterTyul’bashev S.A., Gliantsev A.V.,
Butenko A.V.
What is giant radio galaxy?
• The sizes are essentially more than sizes of parent galaxy
• The emission in radio range is comparable with emission of typical quasars
DRAGNs – Double Radio Sourse Associated with Galactic Nuclei
• DRAGNs as a rule have jets, hot spots, nuclei, radio clouds
• Giant radio galaxies is some part of DRAGNs
• DRAGNs are laboratory for investigation of extra galactic medium
3C 236: 4 Mpc – largest object in Universe
3C 35: 1 Mpc
3C 219: 0.7 Mpc
All pictures are from atlas Leahy http://www.jb.man.ac.uk/atlas/alpha.html
Investigations of giant radio galaxies in Pushchino
• 3C 236, DA 240, 3C 31, 3C 219, NGC 315 and other
3C 236, DA 240: Artyukh et al.,
PAZh, 1988, 14,706(Both source are extended for LPA)
3C 31: Burch, MNRAS, 1977, 181, 599 (Cambridge One- Mile and 5 km telescopes)
3C 31: Artyukh et al., PAZh, 1994, 20, 2583C 31 have angular sizes approximately two times more than at high frequencies. It means the size of 3C 31 is 1.5-2Mpc (one from largest for giant radio galaxies). The result was
confirmed by Rudnick et al., AJ, 2009, 137, 145.
Intermediate conclusions:
• the less frequency the large sources;• largest sources are extended for the Large
Phased Array (beam 0.5*1 degrees);• interferometric systems are lost some part
of extended emission;• the observations at interferometric system is
worse than for antennas with full apertura (for search of giant radio galaxies);
Project: “Cosmic Weather”
• Observations each day during a few years
• From changing of scintillations of sources from day to day we estimate the station of Solar plasma (the report will be today)
Additional projects from observations
• the search of compact (scintillating) radio sources (catalogue of sources - AGNs);
• the search of large scale inhomogeneities of AGNs (voides in Universe);
• the search of giant radio galaxies;
Selection:
• Flux density more than 10 Jy;
• Identification with 4C sources or TEXAS sources;
• Spectra all these sources;
• Test of spectral index (more than 2);
beams: 45’,45’,20-10’,1’,5’,3’
beams: 45’,45’,20-10’,1’,5’,3’
beams: 45’, 1’, 5’,6’, 3’
Possible explanations:
• other large structure (Turte et al. MNRAS, 1962, 124, 459 – no structures at 178 MHz)
• ultra steep spectrum (spectra is standard at high frequencies) ;
• giant radio galaxies (best explanation);
TEXAS 0105+041 is largest source from investigated
• The size of 4C+07.36 is 0.5-1Mpc
How much giant radio galaxies we can find at north sky?
• If flux densities more than 3 Jy;
• If logN/logS ~ 3/2;
• If density of giant radio galaxies is constant;
• We believe ~ 100-200 sources
Conslusion
• The search of candidates to giant radio galaxies on the LPA at 111 MHz at declinations from 3o25’ to 12o40’ were made.
• 4 giant radio galaxies were found
Thank you