Presentation on theme: "An Experience of Aladin Usage for the RC Catalog Radio Source Investigation Zhelenkova Olga, SAO RAS."— Presentation transcript:
An Experience of Aladin Usage for the RC Catalog Radio Source Investigation Zhelenkova Olga, SAO RAS
A survey area is about 100sq.deg.; The RC catalog contains more then 1145 (884) sources in flux range mJy (λ=7.6sm); Radio spectra are defined for 490 radio sources. The deep survey of sky area centered on SS 433 declination was carried out with the RATAN-600 radio telescope in The RC catalog of radio sources is one of results of this observations.
Ultra Steep Spectrum (USS) Sample The following parameters of radio sources were used: (1)a slope of radio source spectrum. Steep spectrum sources were selected (spectral index is in range 0.9 – 1.3); (2)flux density level. morphological type. The objects of FRII morphological type are selected; (3)angular size. Large angular size radio galaxies were not registered for considerable redshifts. Their usual angular sizes are in range 1 arcsec to 1 arcmin; (4)proximity of radio and optical luminosities.
RC catalog objects on the average have fluxes about 100 mJy. Flux densities mean level of the RC catalog fall within inflection area of normalized curve logN-LogS (source number – flux density). Apparently this area may include large number of distant objects. The results of USS sample optical identification are shown in RC catalog objects on the average have fluxes about 100 mJy. Flux densities mean level of the RC catalog fall within inflection area of normalized curve logN-LogS (source number – flux density). Apparently this area may include large number of distant objects. The results of USS sample optical identification are shown in
For optical candidate refinement we use multi band BVRI photometry. Galaxy redshifts and age estimations were done on the 6-m photometric observations with using PEGASE and GISSEL98 model spectral energy distribution packages.
RC J (z=4.51) Objectz mopt mK S1400, α LAS Morph. mJy TN J0924– >24 R D RC J R AD+C VLA J I C+E 6C I D 8C I D+C TN J1338– R AD+C TN J1123– >24.5 R S 7C R D Radio galaxies with z>4
The process of investigation of radio galaxies with steep spectra consists of the following steps: 1.select radio sources with spectral index in a given range [i1,i2]; select radio sources containing flux data for at least 2 frequencies; calculate spectral index i for selected radio sources; get a list of radio sources with spectral index in the range [i1,i2]; 2.select radio sources with the angular size less than a given value d1 and flux value for a given frequency f1 in the range [s1,s2]; 3.find optical sources matching by coordinates with selected radio sources; 4.get a list of radio sources for which the matching optical sources were found; 5.on a user request, for a given pair – radio source and matching optical source: show optical image of the source with over plotted intensity contours of radio image; show radio image of the source with over plotted intensity contours of optical image; 6.request user confirmation of matching of the selected radio and optical sources; 7.calculate stellar magnitudes of the selected candidates at least in U, B, R filters; 8.calculate (U-B) and (B-R) values for each candidates; 9.plot colour - colour diagram to define more exactly the source list; 10.get a searching list of sources– candidates for distant galaxies. The first iteration workflow (for good precision radio coordinates ~1”)
RATAN-600 beam pattern
Radio surveys and catalogs NVSSTXSFIRST Optical surveys DSSSDSS Optical catalogs USNO-B1SDSS2MASS Astronomical resources for the RC catalog identification
Next step in radio source investigation workflow Cross-matching tools with possibility matching in individual source error box Spectral index calculation, fitting radio spectra and using this information for refinement of matching candidates (SpecFind ?) Good quality contour plot tools for radio images (VO service) Program filter for split of Aladin plane backup with multiple catalogs information