VII/73 IRAS Small Scale Structure Catalog, Ver 1.00 (Helou+ 1986)
IRAS Small Scale Structure Catalog
Helou G., Walker D.W.
<Jet Propulsion Laboratory (1986)>
=1988SSSC..C......0H 1988SSSC..C......0H
ADC_Keywords: Photometry, infrared ; Nonstellar objects ; Infrared sources
Mission_Name: IRAS
Description:
Sources resolved by the Infrared Astronomical Satellite in any band
(12, 25, 60, or 100 microns) but smaller than eight arcmin in angular
extent are to be found in the Small Scale Structure Catalog, also
known as the catalog of "small extended sources." The catalog gives
the infrared characteristics of 16740 objects including, e.g.,
galaxies, planetary nebulae and compact H II regions. The catalog
lists for each entry and in each band separately: a position accurate
to about one arcminute (rms); a flux density accurate to 50% (rms)
overall, and better at high signal to noise ratios; a rough indicative
size if a point source is present at the same location; and a variety
of warning and processing flags. If a detailed shape description, or a
more accurate position, flux, or size are needed, these must be
determined from the raw detector output. Incompleteness is a complex
function of wavelength band, brightness, and location, so the absence
of an entry in the SSS Catalog does not necessarily imply the lack of
detectable extended emission. Many entries, mostly at 60 and 100
microns, refer only to emission features that are details in larger
structures known as Galactic cirrus. Complete documentation, including
a description of the catalog format, is contained in the printed
version.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
adc.doc 80 706 The original ADC document
irassss.dat 180 16740 IRAS Small Scale Structure Catalog Sources
assoc.dat 58 5178 Information about positional associations
with sources in other catalogs
meaning.txt 80 235 Details of association catalogues
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See also:
II/125 : IRAS catalogue of Point Sources (IRAS/PSC), Version 2.0 (IPAC 1986)
II/126 : IRAS Serendipitous Survey Catalog (IPAC 1986)
II/156 : IRAS Faint Source Catalog, |b| > 10, Version 2.0 (Moshir+ 1989)
Byte-by-byte Description of file: irassss.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- IRAS (NAME) IRAS source name (XHHMM+DDdA)
11 A1 --- f_IRAS [1-4CDIJKL] (BMFLG) Number of bands in
source and band merging warning flag (3)
12- 13 I2 h RAh (RAHR) Hours RA, equinox 1950.0, epoch 1983.5
14- 15 I2 min RAm (RAMIN) Minutes RA
16- 19 F4.1 s RAs [0/60.0] (RASEC) Seconds RA
20 A1 --- DE- (DSIGN) Sign Dec, equinox 1950.0, epoch 1983.5
21- 22 I2 deg DEd (DECDEG) Degrees Dec
23- 24 I2 arcmin DEm (DECMIN) Minutes Dec
25- 26 I2 arcsec DEs [0/60] (DECSEC) Seconds Dec
27 A1 --- NH12 (NH) Number of hours-confirmed sightings, 12um
28 A1 --- NH25 (NH) Number of hours-confirmed sightings, 25um
29 A1 --- NH60 (NH) Number of hours-confirmed sightings, 60um
30 A1 --- NH100 (NH) Number of hours-confirmed sightings, 100um
31- 38 E8.2 Jy Fnu12 (FLUX) Average non-color corrected, spatially
integrated flux density, 12um
39- 46 E8.2 Jy Fnu25 (FLUX) Average non-color corrected, spatially
integrated flux density, 25um
47- 54 E8.2 Jy Fnu60 (FLUX) Average non-color corrected, spatially
integrated flux density, 60um
55- 62 E8.2 Jy Fnu100 (FLUX) Average non-color corrected, spatially
integrated flux density, 100um
63 A1 --- X12 [0X] (XTALK) Cross-talk flag, 12um (1)
64 A1 --- X25 [0-6X] (XTALK) Cross-talk flag, 25um (1)
65 A1 --- X60 [012X] (XTALK) Cross-talk flag, 60um (1)
66 A1 --- X100 [012X] (XTALK) Cross-talk flag, 100um (1)
67 A1 --- w12 [0-9A-J] (NEARPS) Number of nearby
weeks-confirmed point sources, 12um
68 A1 --- w25 [0-9A-J] (NEARPS) Number of nearby
weeks-confirmed point sources, 25um
69 A1 --- w60 [0-9A-J] (NEARPS) Number of nearby
weeks-confirmed point sources, 60um
70 A1 --- w100 [0-9A-J] (NEARPS) Number of nearby
weeks-confirmed point sources, 100um
71 A1 --- n12 (SES1) Number of nearby FISES entries, 12um
72 A1 --- n25 (SES1) Number of nearby FISES entries, 25um
73 A1 --- n60 (SES1) Number of nearby FISES entries, 60um
74 A1 --- n100 (SES1) Number of nearby FISES entries, 100um
75- 76 I2 --- Cir (CIR) Number of hours-confirmed, 100um-only
point sources
77 A1 --- HD [0-9A-F] (HD) High source density flag,
encoded, one bit per band
78 A1 --- dbl [0-9A-F] (DBLPS) Possibility this is a double
point source (1 bit per band)
79 A1 --- f_PSC [*] Conflict flag with point source
80- 90 A11 --- PSC (PTSRC) Name of IRAS Point Source counterpart
(Cat. II/125) and conflict flag
91- 93 I3 0.1arcmin Psiz12 ? (PSIZ) Size estimate from comparison of FLUX
with PTSRC (II/125) flux, 12um
94- 96 I3 0.1arcmin Psiz25 ? (PSIZ) Size estimate from comparison of FLUX
with PTSRC (II/125) flux, 25um
97- 99 I3 0.1arcmin Psiz60 ? (PSIZ) Size estimate from comparison of FLUX
with PTSRC (II/125) flux, 60um
100-102 I3 0.1arcmin Psiz100 ? (PSIZ) Size estimate from comparison of FLUX
with PTSRC (II/125) flux, 100um
103-104 I2 --- NID (NID) Number of positional associations
105-108 I4 --- IDType (IDTYPE) Type of objects associated
109 A1 --- q_Fnu12 ? (FQLT) 12um flux quality class (2)
110 A1 --- sf12 ? (FCAT) 12um final selection flags (2)
111-116 F6.1 s dRA12 ? (DRA) Right ascension offset from mean
position to 12um (2)
117-120 I4 arcsec dDE12 ? (DDEC) Declination offset from mean
position to 12um (2)
121-123 I3 0.1arcmin Unc12 ? (UNC) 95% confidence diameter for position
at 12um (2)
124-126 I3 --- NS12 ? (NS) Number of individual detections
at 12um (2)
127 A1 --- q_Fnu25 ? (FQLT) 25um flux quality class (2)
128 A1 --- sf25 ? (FCAT) 25um final selection flags (2)
129-134 F6.1 s dRA25 ? (DRA) Right ascension offset from mean
position to 25um (2)
135-138 I4 arcsec dDE25 ? (DDEC) Declination offset from mean
position to 25um (2)
139-141 I3 0.1arcmin Unc25 ? (UNC) 95% confidence diameter for position
at 25um (2)
142-144 I3 --- NS25 ? (NS) Number of individual detections
at 25um (2)
145 A1 --- q_Fnu60 ? (FQLT) 60um flux quality class (2)
146 A1 --- sf60 ? (FCAT) 60um final selection flags (2)
147-152 F6.1 s dRA60 ? (DRA) Right ascension offset from mean
position to 60um (2)
153-156 I4 arcsec dDE60 ? (DDEC) Declination offset from mean
position to 60um (2)
157-159 I3 0.1arcmin Unc60 ? (UNC) 95% confidence diameter for position
at 60um (2)
160-162 I3 --- NS60 ? (NS) Number of individual detections
at 60um (2)
163 A1 --- q_Fnu100 ? (FQLT) 100um flux quality class (2)
164 A1 --- sf100 ? (FCAT) 100um final selection flags (2)
165-170 F6.1 s dRA100 ? (DRA) Right ascension offset from mean
position to 100um (2)
171-174 I4 arcsec dDE100 ? (DDEC) Declination offset from mean
position to 100um (2)
175-177 I3 0.1arcmin Unc100 ? (UNC) 95% confidence diameter for position
at 100um (2)
178-180 I3 --- NS100 ? (NS) Number of individual detections
at 100um (2)
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Note (1): This quantity indicates the extent and kind of cross-talk for
which each component in the source was flagged. As discussed in
IV.B.2a of the Explanatory Supplement, the processor accumulated the
number NXT of detections that might have been caused simply by optical
cross-talk, along with the number NS of detections. If NXT=0 then
XTALK=0 for that band. If NXT > 0, and either (i) (NS-NXT) > 2, or
(ii) (NXT/NS) < 2/3 then XTALK=1 for moderate cross-talk. If NXT > 0,
and neither (i) or (ii) is true then XTALK=2 for severe cross-talk. If
in addition a band component was flagged for cross-talk at the level
of "final source selection", then XTALK is increased by 4. Note that
the component is given a low quality rating if X
Note (2): These fields are blank if the source was not detected in the
corresponding IRAS band.
Quality class assigned to the band component by the scheme described
in Chapter IV and Table IV.A.1 of the Explanatory Supplement. High,
intermediate and low qualities are denoted, respectively, by A, B, and
F. Starting with this flag, data for each band appear separately in
the corresponding quarter of the third data record for the source.
The "final selection" flag ranges from 0 to V according to the table
below. When FCAT is written out in binary notation, the least
significant bit indicates the result of the flux test (IV.B.2.d), and
is set if failed; the next bit refers to the detection count test
(IV.B.2.c), and is set if failed. The next two bits refer to the
repeatability test (IV.B.2.b), and signal one of four possible
outcomes: 00 for intermediate values of N/M except N/M = 2/2; 01 for
low N/M; 10 for high N/M; and 11 for N/M = 2/2 (Table IV.B.3 of the
Explanatory Supplement). The most significant bit in FCAT is set if
the detection is flagged for cross-talk of any kind (IV.B.2.a). Table
3 shows all possible values of FCAT, their representation in the file,
and their meaning.
------------------------------------------------------------------------------
Optical N/M Detection Flux Digital Printed Binary
Cross- Test Count Threshold Version FCAT Notation
Talk [1]
FQLT FCAT XEI FCAT
------------------------------------------------------------------------------
NO MED* PASS PASS B 0 00 00000
NO MED* PASS FAIL F 1 01 00001
NO MED* FAIL PASS F 2 02 00010
NO MED* FAIL FAIL F 3 03 00011
NO LOW PASS PASS F 4 10 00100
NO LOW PASS FAIL F 5 11 00101
NO LOW FAIL PASS F 6 12 00110
NO LOW FAIL FAIL F 7 13 00111
NO HIGH PASS PASS A 8 20 01000
NO HIGH PASS FAIL B 9 21 01001
NO HIGH FAIL PASS B A 22 01010
NO HIGH FAIL FAIL B B 23 01011
NO 2/2 PASS PASS B C 30 01100
NO 2/2 PASS FAIL F D 31 01101
NO 2/2 FAIL PASS F E 32 01110
NO 2/2 FAIL FAIL F F 33 01111
YES MED* PASS PASS F G X00 10000
YES MED* PASS FAIL F H X01 10001
YES MED* FAIL PASS F I X02 10010
YES MED* FAIL FAIL F J X03 10011
YES LOW PASS PASS F K X10 10100
YES LOW PASS FAIL F L X11 10101
YES LOW FAIL PASS F M X12 10110
YES LOW FAIL FAIL F N X13 10111
YES HIGH PASS PASS F O X20 11000
YES HIGH PASS FAIL F P X21 11001
YES HIGH FAIL PASS F Q X22 11010
YES HIGH FAIL FAIL F R X23 11011
YES 2/2 PASS PASS F S X30 11100
YES 2/2 PASS FAIL F T X31 11101
YES 2/2 FAIL PASS F U X32 11110
YES 2/2 FAIL FAIL F V X33 11111
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Note (3): The "band merging" flag gives the number of bands in which
the source has an entry in the last part (q_Fnuxx, Fcatxx, dRAxx,
dDExx, Uncxx, NSxx parameters in bytes 109-180), together with
indications on the "band merging" processing history for that source.
* BMFLG=C or D indicates 3 or 4 mutually confirming (Suppl.V.E.6)
components in the source.
* BMFLG=I, J, K or L indicates 1, 2, 3 or 4 components in a source
having experienced "band merging" complications and having survived
the modified "final selection" discussed in IV.B.3.a.
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Byte-by-byte Description of file: assoc.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- IRAS (NAME) IRAS source name (XHHMM+DDd)
11- 17 I7 --- Seq (RECNO) Main data table record number
for SSS source
18- 20 I3 --- Cat (CATNO) Catalog number (1)
21- 35 A15 --- Source (SOURCE) Source identification
36- 40 A5 --- Type (TYPE) Source type or spectral class
41- 43 I3 arcsec r (RADIUS) Radius vector from IRAS source
to association
44- 46 I3 deg PA (POS) Position angle (E of N), IRAS source
to object
47- 50 I4 --- Field1 (FIELD1) data Field1, catalog dependent (1)
51- 54 I4 --- Field2 (FIELD2) data Field2, catalog dependent (1)
55- 58 I4 --- Field3 (FIELD3) data Field3, catalog dependent (1)
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Note (1): See Table X.B.4 in the "IRAS Catalogs and Atlases Explanatory
Supplement" also included in the file "meaning.txt" in this directory.
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References:
IRAS Catalogs: The Small Scale Structure Catalog, 1988, eds. Helou, G.,
and Walker, D.W. (Washington, DC: GPO), NASA RP-1190, vol 7
(End) Gail L. Schneider [SSDOO/ADC] 25-Sep-1995