III/197 IRAS Low Resolution Spectra (IRAS team, 1987)
IRAS Low Resolution Spectra (LRS)
Joint IRAS Science Working Group
=1987yCat.3197....0J 1987yCat.3197....0J
ADC_Keywords: Spectra, infrared
Mission_Name: IRAS
Description:
The IRAS survey instrumentation included a low-resolution spectrometer
which covered the wavelength range between 8 and 22 um.
The spectrometer operated during the entire survey, providing spectra
of the brighter point sources. For details about the spectrometer, the
reader is referred to the published book, chapter IX.
The spectra included in file "lrs.dat" contain 200 points each,
100 points in the 8-13um range, and 100 points in the 11-22um range.
There is therefore an overlapping between the longer wavelengths
of the first sample and the shorter wavelengths of the second sample.
The data points are stored as scaled integer arrays in the file
"lrs.dat"; the corresponding values of the wavelengths are available
in the file "calib.dat" .
The file "lrs.dat" includes also data taken from the IRAS point
source catalog II/125.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
calib.dat 2400 1 Wavelength table
lrs.dat 960 5425 The IRAS Low Resolution Spectra
assoc.dat 58 10913 Associated sources
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See also:
II/125 : IRAS catalogue of Point Sources, Version 2.0 (IPAC 1986)
Byte-by-byte Description of file: calib.dat
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Bytes Format Units Label Explanations
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1-800 100F8.4 arcmin Angle Angle from center of slit
(one number per sample)
801-1600 100F8.4 um Lambda1 Wavelength in 8-13um
corresponding to each sample
1601-2400 100F8.4 um Lambda2 Wavelength in 11-22um
corresponding to each sample
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Byte-by-byte Description of file: lrs.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- IRAS IRAS source name
12- 13 I2 h RAh Hours RA, equinox 1950.0, epoch 1983.5
14- 15 I2 min RAm Minutes RA
16- 18 I3 0.1s RAds [0/600] Deci-seconds RA
19 A1 --- DE- Sign Dec, equinox 1950.0, epoch 1983.5
20- 21 I2 deg DEd Degrees Dec, equinox 1950.0, epoch 1983.5
22- 23 I2 arcmin DEm Minutes Dec
24- 25 I2 arcsec DEs [0/60] Seconds Dec
26- 34 E9.3 Jy F12 Average non-color corrected flux density, 12um
35- 43 E9.3 Jy F25 Average non-color corrected flux density, 25um
44- 52 E9.3 Jy F60 Average non-color corrected flux density, 60um
53- 61 E9.3 Jy F100 Average non-color corrected flux density 100um
62- 63 I2 --- NLRS Number of significant LRS spectra
64- 65 I2 --- Nsp1 Number of accepted spectra in 8-13um band
66- 67 I2 --- Nsp2 Number of accepted spectra in 11-22um band
68- 69 I2 --- LRSChar Characterization of averaged LRS spectrum (1)
70 I1 --- SpQual1 [1/3] Quality of spectrum in 8-13um band (2)
71 I1 --- SpQual2 [1/3] Quality of spectrum in 11-22um band (2)
72- 73 I2 --- Var Percent likelihood of variability
74- 75 I2 --- NID Number of associations in file "assoc.dat"
76 I1 --- IDType [0/4] Type of association (5)
81- 84 I4 --- Bline1s Average of samples 1-20 in 8-13um band (4)
85- 88 I4 --- Bline1l Average of samples 81-100 in 8-13um band (4)
89- 92 I4 --- Bline2s Average of samples 1-20 in 11-22um band (4)
93- 96 I4 --- Bline2l Average of samples 81-100 in 11-22um band (4)
97-100 I4 --- Noise1 rms noise of 8-13um band (4)
101-104 I4 --- Noise2 rms noise of 11-22um band (4)
105-114 E10.3 --- SNR1 Signal-to-noise ratio in 8-13um band
115-124 E10.3 --- SNR2 Signal-to-noise ratio in 11-22um band
125-134 E10.3 --- Asymm1 Asymmetry in 8-13um band (3)
135-144 E10.3 --- Asymm2 Asymmetry in 11-22um band (3)
145-149 F5.2 --- Sratio Ratio of integrated LRS to 12um flux
150-160 E11.5 W/m2/um SCALE Scale factor for all flux densities (4)
161-560 100I4 --- LRS1 Scaled fluxes in 8-13um band (4)
561-960 100I4 --- LRS2 Scaled fluxes in 11-22um band (4)
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Note (1): See Table IX.D.1 page IX-15 of publication which details
the spectral classification scheme. The leftmost digit indicates
the following typical objects (other are unknown):
1x = star, Sp≤M5 ;
2x = star with not too thick O-rich envelopes
3x = star with thick O-rich envelopes
4x = star with C-rich envelopes
6x = star with very thick O-rich envelopes
7x = star with extremely thick O-rich envelopes
8x = compact HII regions and PNe
Note (2): the quality indicator is
1 = good ; 2 = moderate ; 3 = barely acceptable
Note (3): the value indicates by what fraction of the average signal
the baselines on the short and long wavelength sides of the spectrum
halves differ. A large baseline asymmetry indicates that a confusing
source may have contaminated the spectrum. The baseline asymmetry is
usually large near the Galactic plane.
Note (4): the integers Blinexx, Noisex, and flux values LRSx must be
multiplied by SCALE to get values of flux densities expressed
in W.m-2.um-1. The wavelength array is given in "calib.dat" .
Note (5): the IDType states whether an association was found in:
1 = extragalactic catalog ;
2 = stellar catalog ;
3 = other catalogs ;
4 = multiple types of catalogs.
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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- 11 A11 --- IRAS IRAS source name
12- 17 I6 --- RecNo Record number of IRAS source in lrs.dat
19- 20 I2 --- CatNum Catalog number (1)
21- 35 A15 --- Source Source identification
36- 40 A5 --- Type Source type or spectral class (1)
41- 43 I3 arcsec Radius Radius vector from IRAS source to association
44- 46 I3 deg Pos Position angle (E of N), IRAS source to object
47- 50 I4 --- Field1 Object data field 1, catalog dependent (1)
51- 54 I4 --- Field2 Object data field 2, catalog dependent (1)
55- 58 I4 --- Field3 Object data field 3, catalog dependent (1)
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Note (1): Table X.B.4 in the "IRAS Catalogs and Atlases Explanatory:
Meaning of the Source Association Fields.
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CatNum Field and Meaning
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1 GCVS Type Blank
Field1 = Code gives meaning for Fields 2-3
if Field1 = 1 Field2 and Field3 are B mag [decimag] at
max,min
= 2 Field2 and Field3 are V mag [decimag] at
max,min
= 3 Field2 and Field3 are photographic mag
[decimag] at max,min
= 4 Field2 and Field3 are estimated V mag
[decimag] at max,min
= 5 Field2 is 999 and Field3 is 0
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2 Dearborn Type Blank
Obs. Field1 Code for Field2 (1,2)
Field2 if Field1 is 1, Field2 is red magnitude
[decimag]*
if Field1 is 2, Field2 is 999
Field3 0
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3 Revised Type Blank
AFGL Field1 Magnitude at 4.2 microns [decimag]
Field2 Magnitude at 11 microns [decimag]
Field3 Magnitude at 27 microns [decimag]
------------------------------------------------------------------------------
4 2-Micron Type Blank
Sky Survey Field1 K magnitude [decimag]
Field2 I magnitude [decimag]
Field3 0
------------------------------------------------------------------------------
5 Globules Type Blank
(Wesselius) Field1 999
Field2 Minimum diameter [arcsec]
Field3 Maximum diameter [arcsec]
------------------------------------------------------------------------------
6 RC2 Type Blank
Field1 Harvard V magnitude [decimag]
Field2 B(T) [decimag]
Field3 D(0) [arcsec]
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7 Stars with Type Blank
em. lines Field1 V magnitude [decimag]
Field2 999
Field3 0
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8 Equatorial Type Blank
IR Cat. Field1 Flux density [1.0E-16 W/cm**2/um]
at 2.7 microns
Field2 999
Field3 0
------------------------------------------------------------------------------
9 UGC Type Blank
Field1 Zwicky magnitude [decimag]
Field2 Minimum diameter [arcsec] in B
Field3 Maximum diameter [arcsec] in B
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10 MCG Type Blank
Field1 999
Field2 Minimum diameter [arcsec] in B
Field3 Maximum diameter [arcsec] in B
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11 Strasbourg Type Blank
Planetary Nebulae Field1 V magnitude of Nebula [decimag]
Field2 B magnitude of Center Star [decimag]
Field3 Minimum diameter of Nebula [arcsec]
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12 Zwicky Type Blank
Field1 Zwicky magnitude [decimag]
Field2 999
Field3 0
------------------------------------------------------------------------------
13 SAO Type Spectral Type
Field1 V magnitude [decimag]
Field2 p(g) magnitude [decimag]
Field3 0
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14 ESO/ Type First 3 characters of object type
Uppsala Field1 B magnitude [decimag]
Field2 Maximum diameter [arcsec]
Field3 Minimum diameter [arcsec]
------------------------------------------------------------------------------
15 Bright Type Spectral Type
Stars Field1 V magnitude [decimag]
Field2 B-V [centimag]
Field3 U-B [centimag]
------------------------------------------------------------------------------
16 Suspected Type Spectral Information
Var. Field1 V magnitude at maximum [decimag]
Field2 999
Field3 0
------------------------------------------------------------------------------
17 Carbon Type Spectral Type (May be truncated)
Stars Field1 p(g) magnitude [decimag]
Field2 V magnitude [decimag]
Field3 I magnitude [decimag]
------------------------------------------------------------------------------
18 Gliese Type Spectral Type (May be truncated)
Field1 V magnitude [decimag]
Field2 B-V magnitude [millimag]
Field3 U-B magnitude [millimag]
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19 S Stars Type Blank
Field1 p(g) magnitude [millimag]
Field2 V magnitude [decimag]
Field3 I magnitude [decimag]
------------------------------------------------------------------------------
20 Parkes HII Type Blank
Survey Field1 999
Field2 Minimum diameter [arcsec]
Field3 Maximum diameter [arcsec]
------------------------------------------------------------------------------
21 Bonn HII Type Blank
Survey Field1 Flux density at 4.875 GHz (Jy)
Field2 Diameter [arcsec]
Field3 0
------------------------------------------------------------------------------
22 Blitz Type Blank
Field1 Diameter [arcsec]
Field2 V(CO) [Km/s]
Field3 Peak T(A) [degrees K]
------------------------------------------------------------------------------
23 OSU Type Blank
Field1 999
Field2 999
Field3 Diameter [arcsec]
------------------------------------------------------------------------------
24 IRC Type C if 2.2 micron sources are possibly
confused, w/good pos. blank otherwise
Field1 Right ascension difference (IRC-IRAS)
[deciseconds of time]
Field2 Declination difference (IRC-IRAS)
[seconds of arc]
Field3 0
------------------------------------------------------------------------------
25 DDO Type Blank
Field1 999
Field2 999
Field3 0
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26 Arp Type Blank
Field1 999
Field2 999
Field 0
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27 Markarian Type Blank
Field1 999
Field2 999
Field3 0
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28 Strong Type Object type (GAL or QSO)
5 GHz Field1 V magnitude [decimag]
Field2 5 GHz flux density [deciJy]
Field3 0
------------------------------------------------------------------------------
29 Veron- Type Object classification
Veron Field1 V magnitude [decimag]
Field2 Redshift x 1000
Field3 0
------------------------------------------------------------------------------
30 Zwicky Type Blank
8 Lists Field1 999
Field2 999
Field3 0
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31 VV Type Blank
Field1 Special flag, (see below) 999 otherwise
Field2 999
Field3 0
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VV Catalog Special Flags (Catalog 31)
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Field1 Explanation
10 VV 10 has the same coordinates as VV 29 in the VV Atlas. The
UGC was used to confirm that the coordinate is correct for VV
29 and erroneous for VV 10. The UGC position for VV 10 = UGC
10814 was adopted.
11 The VV position is substantially different (>400") from
positions for the object in other catalogs. The VV position
has been assumed to be in error because two or more other
catalogs agree on a different position. The UGC position has
been adopted.
12 Same as for 11, but the OSU position has been adopted.
13 The position in the VV Atlas, and the position listed for the
VV object in the OSU are in disagreement. The true position
has been established to be close to that of the OSU by the use
of overlay transparencies on the POSS. The OSU position has
been adopted.
14 Same as for 13, but the OSU position is not very good either,
so a new position has been measured (accurate to about 1').
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(End) Francois Ochsenbein [CDS] 02-Apr-1997