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