Application of IVOA software tools for radio sources investigation Zhelenkova O., Kopylov A., Chernenkov V. The interrelationship between the objects of astronomical catalogs in the different ranges of electromagnetic spectrum and their association into the real astrophysical source has obvious scientific interest. Astronomical community actively uses the Internet for the access to the scientific information, but the heterogeneity of data and their constantly growing volume is the certain difficulty. The gathering of information even about one celestial object is time-taking work because of a large quantity of resources, data access, formats of the obtained results and formats of input data of the program applications, used for further analysis. The community activity on the creation of the architecture of information interaction, standards, format specifications, data models and services, which increase the efficiency of work with the data, coordinates International Virtual Observatory Alliance (IVOA). Within the framework of this activity is created system Astrogrid (http://www.astrogrid.org) and software tools Aladin (.http://aladin.u-strasbg.fr) and TOPCAT (http://www.star.bris.ac.uk/~.mbt/topcat/), which make it possible to realize the distributed computing and data access. AstroGrid developers selected ten typical tasks, connected with physics of stars, galaxies, interstellar medium and the Sun, whose solution is impossible without the distributed computing and requests to the different information sources, analysis and visualization of the large volumes of data. In the sense of information technologies, we can represent the tasks are as a form of scenarios. This is the certain type assignment of the actions, produced for extraction and data analysis from www-resources. AstroGrid developers decomposed scenarios on the component tasks, on the base that created the functionality of the system. We decided to analyze the usage of existing software tools for investigation the radio sources list. The radio sources identification can be considered as the sequence of the interconnected tasks, beginning from the extraction of data, their analysis and visualizations of results. Optical identification is not simple task for the automation because the radio sources are extensive, has complex structure and, therefore, one source can be fetch in the catalog as a few objects. As the radio sources list we used the RC sample, namely the objects, which fell into the region of surveys FIRST and SDSS (8h11m-16h25m on the right ascension and with the width on the declination, which includes all sources RC, with the total area of ~120sq.deg.). The RC catalog has insufficient coordinate accuracy for the optical identification; therefore is necessary the refinement of coordinates by cross matching with the more precise radio catalog. We used NVSS as the reference coordinate catalog. For the program cross-identification of the RC sample, we tested the different algorithms in the IVOA program applications, namely, the search of the nearest neighbors with different radii of the separation between the adjacent sources and the algorithm from the SPECFIND package, which considers different angular resolution of compared radio catalogs. The algorithms gave the low percentage of coincidences, and it is required the their modification, i.e., the addition of constrains and conditions, which can be used for the binding rows of different catalogs into one physical object not only coordinate coincident, but also other conditions, caused by the radio source properties. We are carrying out the detailed identification of the RC sample to study of the properties of radio sources at the frequency of 3.9GHz and find possible empirical constrains for changing the cross matching algorithm For the work we use the catalogs and surveys in the optical and the radio-frequency band - VLSS, TXS, NVSS, GB6, FIRST, SDSS, 2MASS, USNO-B1. We evaluated the fraction of single-component and multicomponent radio sources in survey FIRST, on basis of which (after the identification of the RC catalog objects with it) carried out optical identification. Spectral data in the radio-frequency band from 74MHz to 4.85GHz are acquired for the sample. For 60% of radio sources identified with the objects of the radio catalogs we discovered optical candidates in SDSS survey.