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III/197             IRAS Low Resolution Spectra    (IRAS team, 1987)

IRAS Low Resolution Spectra (LRS) Joint IRAS Science Working Group <NASA RP-1190 (1987)>
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:
FileName Lrecl Records Explanations
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
See also: II/125 : IRAS catalogue of Point Sources, Version 2.0 (IPAC 1986) Byte-by-byte Description of file: calib.dat
Bytes Format Units Label Explanations
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
Byte-by-byte Description of file: lrs.dat
Bytes Format Units Label Explanations
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)
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.
Byte-by-byte Description of file: assoc.dat
Bytes Format Units Label Explanations
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)
Note (1): Table X.B.4 in the "IRAS Catalogs and Atlases Explanatory: Meaning of the Source Association Fields. ------------------------------------------------------------------------------ CatNum Field and Meaning ------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------ 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] ------------------------------------------------------------------------------ 7 Stars with Type Blank em. lines Field1 V magnitude [decimag] Field2 999 Field3 0 ------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------ 10 MCG Type Blank Field1 999 Field2 Minimum diameter [arcsec] in B Field3 Maximum diameter [arcsec] in B ------------------------------------------------------------------------------ 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] ------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------ 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] ------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------ 26 Arp Type Blank Field1 999 Field2 999 Field 0 ------------------------------------------------------------------------------ 27 Markarian Type Blank Field1 999 Field2 999 Field3 0 ------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------ 31 VV Type Blank Field1 Special flag, (see below) 999 otherwise Field2 999 Field3 0 ------------------------------------------------------------------------------ VV Catalog Special Flags (Catalog 31) ------------------------------------------------------------------------------ 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'). ------------------------------------------------------------------------------

(End) Francois Ochsenbein [CDS] 02-Apr-1997
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