User:Mike Peel/Radio Recombination Lines

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Radio Recombination Lines (RRLs) are spectral lines emitted during recombination (Plasma recombination?). They are observed at radio frequencies.

Lines

  • Due to the formation of atoms through the recombination of electrons and ions[1]
  • Lines come from transitions between highly excited atomic levels.[1]
  • At radio frequencies, referred to as 'Radio Recombination Lines'.[1]
  • Emitted by hydrogen atoms[2]
  • In the interstellar medium, can have quantum levels up to n=1000, and with radiuses of the order of a tenth of a millimetre.[1]
  • Maser effects[2]
  • Low frequencies contaminated by synchrotron emission.[2]

Implications

  • Probe of the gas in star-forming regions.[1]
  • Depends on gas densities and temperatures.[1]
  • Can estimate electron temperatures.[3][2]
  • Can estimate star formation rates.[2]
  • Dust attenuation[2]

Observations

Solar system

  • Detected in the Sun.[1]

Galactic regions

  • Galactic HII regions[3]
  • Galactic plane[4]

Nearby galaxies

The first extragalactic detection of RRLs beyond the Magellanic clouds was the H166α line in Messier 82 in 1977.[5]

Galaxy First detection Lines observed Telescopes
Circinus Galaxy 2008[6] H92α[6]
Messier 33 2004[7] H110α[7]
Messier 82 1977[5]

H26α,[8] H27α,[8] H29α,[8] H30α,[9] H41α,[8] H53α,[10] H85α,[11] H92α,[3][10] H102α,[12][11] H166α[5]

36.6m telescope at Haystack Observatory,[3] Algonquin Radio Observatory[12], Westerbork Synthesis Radio Telescope[5]
NGC 253 1977[13]

H40α,[2] H102α,[13] H112α[14]

Algonquin Radio Observatory[12], ALMA[2]
NGC 1808 2008[6] H92α[6]

References

  1. ^ a b c d e f g Gordon, M. A.; Sorochenko, R.L. (2008). Radio recombination lines: their physics and astronomical applications. New York: Springer. ISBN 978-0-387-09604-9.
  2. ^ a b c d e f g h Bendo, G. J.; Beswick, R. J.; D'Cruze, M. J.; Dickinson, C.; Fuller, G. A.; Muxlow, T. W. B. (1 May 2015). "ALMA observations of 99 GHz free-free and H40  line emission from star formation in the centre of NGC 253". Monthly Notices of the Royal Astronomical Society: Letters. 450 (1): L80–L84. doi:10.1093/mnrasl/slv053. {{cite journal}}: no-break space character in |title= at position 46 (help)
  3. ^ a b c d Chaisson, E. J.; Rodriguez, L. F. (June 1977). "Detection of extragalactic radio recombination line emission from M82". The Astrophysical Journal. 214: L111. doi:10.1086/182453.
  4. ^ Alves, Marta I. R.; Davies, Rodney D.; Dickinson, Clive; Davis, Richard J.; Auld, Robbie R.; Calabretta, Mark; Staveley-Smith, Lister (April 2010). "Diffuse radio recombination line emission on the Galactic plane between l=36° and 44°". Monthly Notices of the Royal Astronomical Society. doi:10.1111/j.1365-2966.2010.16595.x.
  5. ^ a b c d Shaver, P. A.; Churchwell, E.; Rots, A. H. (March 1977). "Stimulated Recombination Line Emission from M 82". The Astronomy & Astrophysics. 55: 435.
  6. ^ a b c d Roy, A. L.; Goss, W. M.; Anantharamaiah, K. R. (May 2008). "Detection of the H92α recombination line from the starbursts in the Circinus galaxy and NGC 1808". Astronomy and Astrophysics. 483 (1): 79–88. doi:10.1051/0004-6361:20077405. {{cite journal}}: no-break space character in |title= at position 65 (help)
  7. ^ a b Araya, Esteban; Baan, Willem A.; Hofner, Peter (October 2004). "Studies of Extragalactic Formaldehyde and Radio Recombination Lines". The Astrophysical Journal Supplement Series. 154 (2): 541–552. doi:10.1086/423246.
  8. ^ a b c d Seaquist, E. R.; Carlstrom, J. E.; Bryant, P. M.; Bell, M. B. (July 1996). "Millimeter Recombination Line Emission in the Starburst Galaxy M82". The Astrophysical Journal. 465: 691. doi:10.1086/177454.
  9. ^ Seaquist, E. R.; Kerton, C. R.; Bell, M. B. (July 1994). "Millimeter recombination lines and the state of ionized gas in M82". The Astrophysical Journal. 429: 612. doi:10.1086/174348.
  10. ^ a b Rodriguez‐Rico, C. A.; Viallefond, F.; Zhao, J.‐H.; Goss, W. M.; Anantharamaiah, K. R. (December 2004). "Very Large Array H92α and H53α Radio Recombination Line Observations of M82". The Astrophysical Journal. 616 (2): 783–803. doi:10.1086/425109.
  11. ^ a b Bell, M. B.; Seaquist, E. R. (July 1978). "Radio Recombination Line Studies of M82 and Other Galaxies". The Astrophysical Journal. 223: 378. doi:10.1086/156272.
  12. ^ a b c Bell, M. B.; Seaquist, E. R. (April 1977). "Detection of the H 102a Recombination Line in M 82". The Astronomy & Astrophysics. 56: 461.
  13. ^ a b Seaquist, E. R.; Bell, M. B. (1977). "Detection of the H102α Recombination Line in NGC253". The Astronomy & Astrophysics. 60: L1.
  14. ^ Mebold, U.; Shaver, P. A.; Bell, M. B.; Seaquist, E. R. (Feb 1980). "Radio recombination lines from NGC 253". Astronomy & Astrophysics. 82: 272. {{cite journal}}: Cite has empty unknown parameter: |1= (help)

Further reading

  • Gordon, M. A.; Sorochenko, R.L. (2008). Radio recombination lines: their physics and astronomical applications. New York: Springer. ISBN 978-0-387-09604-9.
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