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J/A+AS/108/79 Ultra-steep spectrum radio sources (Roettgering+, 1994)
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Samples of ultra-steep spectrum radio sources
Roettgering H.J.A., Lacy M., Miley G.K., Chambers K.C., Saunders R.
<Astron. Astrophys. Suppl. Ser. 108, 79 (1994)>
=1994A&AS..108...79R (SIMBAD/NED Reference)
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ADC_Keywords: Radio sources
Keywords: astronomical data bases: surveys - galaxies: active -
radio continuum: galaxies
Description:
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.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
source 146 1168 Source list
source.tex 180 1531 LaTeX version of source
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Byte-by-byte Description of file: source
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Bytes Format Units Label Explanations
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1- 10 A10 --- Samples Name of the samples to which the source
belongs (1)
12- 19 A8 --- Name Source name in IAU B1950.0 format
21- 22 A2 --- m_Name [1-5ABc ] Component designator (2)
24- 25 I2 h RAh []? Right ascension J2000
27- 28 I2 min RAm []? Right ascension J2000
30- 34 F5.2 s RAs []? Right ascension J2000
36 A1 --- DE- Declination sign
37- 38 I2 deg DEd []? Declination J2000
40- 41 I2 arcmin DEm []? Declination J2000
43- 46 F4.1 arcsec DEs []? Declination J2000
51- 52 I2 h RAh1950 []? Right ascension B1950
54- 55 I2 min RAm1950 []? Right ascension B1950
57- 61 F5.2 s RAs1950 []? Right ascension B1950
63 A1 --- DE-1950 Declination sign
64- 65 I2 deg DEd1950 []? Declination B1950
67- 68 I2 arcmin DEm1950 []? Declination B1950
70- 73 F4.1 arcsec DEs1950 []? Declination B1950
75- 78 I4 mJy Speak Peak brightness
80- 83 I4 mJy Sint []? Integrated flux density
85- 88 F4.2 --- R []? Ratio of the integrated VLA flux density
to the flux density obtained from the
NRAO Green Bank 1400 MHz
90- 94 F5.2 --- alpha(l) []? Low frequency spectral index
96- 99 F4.2 --- e_alpha(l) []? Rms uncertainty on alpha(l)
101-105 F5.2 --- alpha(h) []? High frequency spectral index
107-110 F4.2 --- e_alpha(h) []? Rms uncertainty on alpha(h)
112-125 A14 --- Cat [a-r ] Radio catalogues that have been used in
the spectral index calculations (3)
127-132 A6 --- n_Cat Notes on catalogues (4)
134-135 A2 --- Mul [DPMTF ] D = double, P = point source,
T = triple DF = diffuse, M = complex
137 A1 --- l_Size Limit flag on Size
138-142 F5.1 arcsec Size []? Angular size measured from VLA maps
144-146 I3 deg PA []? Position angle measured from VLA maps
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Note (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
Note (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.
Note (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>
Note (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
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Remarks:
(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.
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References:
(BWE) Becker R.H., White R.L., Edwards A.L.
=1991ApJS...75....1B, Cat. <VIII/13>
(NRAO) Condon J.J., Broderick J.J.
=1985AJ.....90.2540C, in Cat. <VIII/6>
=1986AJ.....91.1051C, in Cat. <VIII/6>
Condon J.J., Broderick J.J., Seielstad G.A.
=1989AJ.....97.1064C
(87GB) Gregory P.C., Condon J.J
=1991ApJS...75.1011G, Cat. <VIII/14>
(6C2) Hales S.E.G., Baldwin J.E., Warner P.J.
=1988MNRAS.234..919H, Cat. <VIII/21>
(MRC) Large M.I., Cram L.E., Burgess A.M.
=1981MNRAS.194..693L, Cat. VIII/16
(8C) Rees N.
=1990MNRAS.244..233R
(WB) White R.L., Becker R.H.
=1992ApJS...79..331W, Cat. <VIII/17>
(PKS) Wright A., Otrupcek R., the PKSCAT90 Catalogue
=1992BICDS..41...47W, Cat. <VIII/15>
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(End) Patricia Bauer [CDS] 01-Jul-1994, rev. Francois Ochsenbein 19-Aug-1996