J/A+AS/108/79 J/A+AS/108/79 Ultra-steep spectrum radiosources H J A Roettgering M Lacy G K Miley K C Chambers R Saunders Astron. Astrophys. Suppl. Ser. 108 79 1994 1994A&AS..108...79R Radio sources surveys galaxies: active radio continuum: galaxies Radio sources with ultra-steep spectra (USS; spectral index <~ -1.0) have been found to be excellent tracers of galaxies at redshifts z>~2. The samples are selected from the set of catalogues referenced below, in a range of frequencies from 38 to 408MHz; they are are fainter by a factor of three than the previously well-studied samples of USS sources from 4C. Snapshot observations of sources from these samples have been made with the VLA at 1.5arcsec resolution and are presented in the printed paper. The list of the sources (Appendix A of the paper) includes positions, flux densities and radio structures for a total number of 605 sources derived from these observations.

Samples Name of the samples to which the source belongs number=1 the 9 samples are defined in Table 4 of the paper; the names are related to the lowest frequency (MHz): 408A, 408B, 365A, 365B, 178, 151I, 38A, 38B, 38C --- Name Source name in IAU B1950.0 format --- m_Name Component designator number=2 the component indicator may be: - a number indicates that the component belongs to the main central radio source. A 'c' after a number indicates that this component is probably the core component. - a letter indicates that the object is bright (presumably) serendipitous source visible in the VLA map in a 4'x4' region surrounding the source. --- RAh Right ascension J2000 h RAm Right ascension J2000 min RAs Right ascension J2000 s DE- Declination sign --- DEd Declination J2000 deg DEm Declination J2000 arcmin DEs Declination J2000 arcsec RAh1950 Right ascension B1950 h RAm1950 Right ascension B1950 min RAs1950 Right ascension B1950 s DE-1950 Declination sign --- DEd1950 Declination B1950 deg DEm1950 Declination B1950 arcmin DEs1950 Declination B1950 arcsec Speak Peak brightness mJy Sint Integrated flux density mJy R Ratio of the integrated VLA flux density to the flux density obtained from the NRAO Green Bank 1400 MHz --- alpha(l) Low frequency spectral index --- e_alpha(l) Rms uncertainty on alpha(l) --- alpha(h) High frequency spectral index --- e_alpha(h) Rms uncertainty on alpha(h) --- Cat Radio catalogues that have been used in the spectral index calculations number=3 the catalogues are a: 8C(38 MHz) <1990MNRAS.244..233R> b: PKS(80 MHz) <VIII/15> c: 6C2(151 MHz) <VIII/21> d: PKS(178 MHz) <VIII/15> e: TXS(365 MHz) The Texas Survey (see Douglas et al, 1980, Univ. Texas Publ. in Astronomy 17, 1) f: TXS:BWE(365 MHz) g: PKS(408 MHz) <VIII/15> h: MRC(408 Mhz) <VIII/16> i: NRAO(1400 MHz) <VIII/6> j: WB(1400 MHz) <VIII/17> k: PKS(1410 MHz) <VIII/15> l: VLA(1465 MHz) m: PKS(2700 MHz) <VIII/15> n: NRAO(4850 MHz) <VIII/6> o: 87GB(4580 MHz) <VIII/14> p: BWE(4589 MHz) <VIII/13> q: WB(4580 MHz) <VIII/17> r: PKS(5000 MHz) <VIII/15> --- n_Cat Notes on catalogues number=4 Various flags indicating catalogue problems and/or confusion: Flags a to h have been directly copied from three catalogues at 1400 and 4850 MHz (WB, BWE and 87GB). Flags r to x indicate inconsistencies and how various upper limits have been treated. *: The spectral index/indices is/are unreliable, since there are warnings in one of the three 1400/4580 MHz catalogues (a to h) and/or there is a bright confusing source in the VLA field (z) a: In WB a 1400 MHz source is reported to match more than one 1400 MHz or 365 MHz source so that confusion is likely b: In WB a 1400 MHz source is reported to be extended at 1400 MHz c: In WB a 1400 MHz source is reported to be extended at 4850 MHz d: In BWE a 4850 MHz source is reported to be extended at 4850 MHz Note that the flags c and d are not always simultaneously present e: In the BWE the separation between the NRAO 4850 MHz and the Texas 365 MHz positions is reported to be greater than 100 arcsecs f: In 87GB a source is reported to be extended or a blend of two or more point sources (Flag E in the original catalogue) g: In 87GB a source has a warning that it is a weak source with a large zero offset, a narrow minor axis, or possibly confused; less reliable than most (Flag W in the original catalogue) h: In 87GB a source is reported to be confused (Flag C in the original catalogue) q: Difference of 4850 MHz flux densities of 87GB and our fitting routines are greater than 10 mJy r: Difference in the 365 MHz flux densities from the version of the Texas catalogue that we used and the version that WB used u: Since no Texas flux density is present in WB catalogue, we used the flux density from our version of the Texas Catalogue v: No 1400 MHz flux densities in WB w: Since no 4850 MHz flux densities is present in WB, we used the 87GB 4850 MHz flux density x: No WB and 87GB 4850 MHz flux densities. Our determination for the 4850 MHz NRAO flux densities is used if this flux density >15mJy z: A bright serendipitous source in the VLA field Notes on individual sources: 0141+356 A serendipitous double radio galaxy in the field is present about 1.5 minutes from components `1' and `2'. 0309-047 Component `A' is probably serendipitous. 0707+810 This is resolved into two separate sources. The northern source has an asymmetric FRII structure; the southern a bright central component and low surface brightness lobes just detectable on the low-resolution VLA map. CLFST observations show that both sources have similar fluxes at 151-MHz (~100 mJy for the northern source and ~150 mJy for the southern), but the southern source has a steeper spectral index; hence this object should dominate the flux at the selection frequency of 38-MHz. 0906+691 The VLA map shows three diffuse components; a CLFST map shows two distinct sources, the southern of which is resolved into two components and may therefore either be a single large source or two smaller ones. 1127+831 A Ryle Telescope map at 5GHz [calibrated and analysed as detailed in Lacy et al. (1993)] only detects component 1, but shows it to have a very steep radio spectrum (alpha^{1490}^_{5000}_=-1.1), suggesting that it is some form of hotspot. 1227+609 It is not clear whether the three components are related. 1323+080 It is not clear if component `2' is real. 1345-309 Diffuse radio source. Coordinates are derived from the moments of the source brightness. 1350+635 This 80 arcsec source has a faint central component and diffuse lobes which barely show up on the VLA map. CLFST observations confirm the presence of the lobes. 1436+157 The double radio galaxy with components 'A' and 'B' is probably not related to the double radio galaxy with components '1' and '2'. 1611+452 It is not clear whether the three components belong to one source. 1652+027 Two components separated by 233", so may not be a single source. 1659+440 Component A probably is probably a separate serendipitous source. 1718+630 Component '1' serendipitous or related to double radio source? 1942+631 Component A related to central radio source ? 2207+038 It is not clear whether the two components belong to one source. 2324+071 Diffuse double lobed radio source. Position of lobes measure from the tapered maps. 2335-125 It is not clear whether the two components belong to one source. --- Mul D = double, P = point source, T = triple DF = diffuse, M = complex --- l_Size Limit flag on Size --- Size Angular size measured from VLA maps arcsec PA Position angle measured from VLA maps deg source.texLaTeX version of source Patricia Bauer CDS 1994, rev. Francois Ochsenbein 19-Aug-1996Jul01 J_A+AS_108_79.xml