Handbook of Frequency Allocations and Spectrum Protection for Scientific Uses: Second Edition (2015)

Chapter: Appendix D: International Astronomical Union Spectral Lines of Most Importance Between 300 and 1000 GHz

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Suggested Citation: "Appendix D: International Astronomical Union Spectral Lines of Most Importance Between 300 and 1000 GHz." National Academies of Sciences, Engineering, and Medicine. 2015. Handbook of Frequency Allocations and Spectrum Protection for Scientific Uses: Second Edition. Washington, DC: The National Academies Press. doi: 10.17226/21774.
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D

International Astronomical Union Spectral Lines of Most Importance Between 300 and 1000 GHz

At each triennial meeting of the General Assembly, the International Astronomical Union (IAU) carefully reviews the list of astrophysically most important spectral lines that it maintains. The IAU expresses the need to protect these frequency bands from in-band, band-edge, and harmonic emissions, especially from spaceborne transmitters.

In preparation for World Radiocommunication Conference 2000, which revised the allocations above 71 GHz, a millimeter-wavelength working group of the Scientific Committee on Frequency Allocations for Radio Astronomy and Space Science (IUCAF) examined all then-known transitions in the millimeter and submillimeter wavebands. The working group selected a limited number of the astrophysically most important spectral lines to supplement the earlier lists, such as those produced by the IAU, to be used in allocating frequency bands to the Radio Astronomy Service. Spectral lines between 300-1000 GHz are listed in Table D.1. Unless otherwise noted, the band limits are Doppler-shifted frequencies corresponding to radial velocities of ±300 km/s, consistent with line radiation occurring in our Milky Way galaxy. Although no formal frequency allocations are established above 275 GHz, the International Telecommunication Union (ITU) Radio Regulation 5.565 urges administrations to take all practicable steps to protect passive services from harmful interference in the frequency range of 275-1000 GHz. Of particular note are the following frequency bands, which are identified for passive use by the Radio Astronomy Service: 275-323 GHz, 327-371 GHz, 388-424 GHz, 426-442 GHz, 453510 GHz, 623-711 GHz, 795-909 GHz, and 926-945 GHz. These frequency bands correspond to atmospheric “windows” (see Figure 2.6) that permit ground-based observations of cosmic sources from high, dry sites.

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Suggested Citation: "Appendix D: International Astronomical Union Spectral Lines of Most Importance Between 300 and 1000 GHz." National Academies of Sciences, Engineering, and Medicine. 2015. Handbook of Frequency Allocations and Spectrum Protection for Scientific Uses: Second Edition. Washington, DC: The National Academies Press. doi: 10.17226/21774.
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TABLE D.1 The Most Important Spectral Lines Between 300 and 1000 GHz

SpeciesFormulaFrequency (GHz)Suggested Minimum Band (GHz)Notes1
HydroniumH3O+307.192306.88-307.50 
Deuterated waterHDO313.750313.44-314.06 
Carbon monoxideC18O329.330329.00-329.66 
Carbon monoxide13CO330.587329.49-330.92 
Carbon monosulphideCS342.883341.74-343.23 
Carbon MonoxideCO345.796345.45-346.14 
Hydrogen cyanideHCN354.484353.30-354.84 
FormyliumHCO+356.734355.54-357.09 
OxygenO2368.498368.13-368.87 
DiazenyliumN2H+372.672372.30-373.042
Water vaporH2O380.197379.82-380.582
HydroniumH3O+388.459388.07-388.85 
Carbon monosulphideCS391.847390.54-392.24 
OxygenO2424.763424.34-425.19 
Carbon monoxideC18O439.088438.65-439.53 
Carbon monoxide13CO440.765439.30-441.21 
Carbon monoxideCO461.041459.50-461.50 
Deuterated waterHDO464.925464.46-465.39 
CarbonCI492.162490.52-492.65 
Deuterated waterHDO509.292508.78-509.80 
Hydrogen cyanideHCN531.716529.94-532.252
Carbon monosulphideCS538.689536.89-539.232
Water vaporH218O547.676547.13-548.222
Carbon monoxide13CO550.926549.09-551.482
Water vaporH2O556.936556.38-557.492
Ammonia15NH3572.113571.54-572.692
AmmoniaNH3572.498571.93-573.072
Carbon monoxideCO576.268574.35-576.842
Carbon monosulphideCS587.616587.03-588.202
Deuterated waterHDO599.927599.33-600.532
Water vaporH2O620.700620.08-621.322
Hydrogen chlorideHCl625.040624.41-625.67 
Hydrogen chlorideHCl625.980625.35-626.61 
Carbon monosulphideCS636.532634.41-637.17 
Carbon monoxide13CO661.067658.86-661.73 
Carbon monoxideCO691.473689.17-692.16 
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Suggested Citation: "Appendix D: International Astronomical Union Spectral Lines of Most Importance Between 300 and 1000 GHz." National Academies of Sciences, Engineering, and Medicine. 2015. Handbook of Frequency Allocations and Spectrum Protection for Scientific Uses: Second Edition. Washington, DC: The National Academies Press. doi: 10.17226/21774.
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SpeciesFormulaFrequency (GHz)Suggested Minimum Band (GHz)Notes1
OxygenO2715.393714.68-716.112
Carbon monosulphideCS734.324733.59-735.062
Water vaporH2O752.033751.28-752.792
OxygenO2773.840773.07-774.612
Hydrogen cyanideHCN797.433794.77-798.23 
FormyliumHCO+802.653799.98-803.46 
Carbon monoxideCO806.652803.96-807.46 
CarbonC I809.350806.65-810.16 
Carbon monosulphideCS832.057829.28-832.89 
OxygenO2834.146833.31-834.98 
Carbon monosulphideCS880.899877.96-881.78 
Water vaporH2O916.172915.26-917.092
Carbon monoxideCO921.800918.72-922.722
Carbon monosulphideCS929.723926.62-930.65 
Water vaporH2O970.315969.34-971.292
Carbon monosulphideCS978.529977.55-979.512
Water vaporH2O987.927986.94-988.922

NOTES:

1. The band limits are the Doppler-shifted frequencies corresponding to radial velocities of ±300 km/s (consistent with line radiation occurring in our Milky Way galaxy).

2. These lines are observable only outside the atmosphere.

SOURCE: Data and further information can be found in International Telecommunication Union, RA 314 Series: Preferred Frequency Bands for Radio Astronomical Measurements, June 2003, http://www.itu.int/dms_pubrec/itu-r/rec/ra/R-REC-RA.314-10-200306-I!!PDF-E.pdf.

Page 241 Cite Bookmark
Suggested Citation: "Appendix D: International Astronomical Union Spectral Lines of Most Importance Between 300 and 1000 GHz." National Academies of Sciences, Engineering, and Medicine. 2015. Handbook of Frequency Allocations and Spectrum Protection for Scientific Uses: Second Edition. Washington, DC: The National Academies Press. doi: 10.17226/21774.
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Page 242 Cite Bookmark
Suggested Citation: "Appendix D: International Astronomical Union Spectral Lines of Most Importance Between 300 and 1000 GHz." National Academies of Sciences, Engineering, and Medicine. 2015. Handbook of Frequency Allocations and Spectrum Protection for Scientific Uses: Second Edition. Washington, DC: The National Academies Press. doi: 10.17226/21774.
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Page 243 Cite Bookmark
Suggested Citation: "Appendix D: International Astronomical Union Spectral Lines of Most Importance Between 300 and 1000 GHz." National Academies of Sciences, Engineering, and Medicine. 2015. Handbook of Frequency Allocations and Spectrum Protection for Scientific Uses: Second Edition. Washington, DC: The National Academies Press. doi: 10.17226/21774.
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Next Chapter: Appendix E: International Astronomical Union Spectral Lines of Most Importance Above 1 THz
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