Letter | Published:

Emission at 3.3 µm and evidence for dust in 3C273

Abstract

The presence of dust grains in a variety of astronomical environments has been established from many IR observations1. Of particular interest is whether dust exists in the highly energetic quasars, and in the less energetic (but apparently similar) Seyfert 1 galaxies. Whilst both quasars and Seyfert 1 galaxies exhibit enhanced radiation over just the wavebands expected of thermal dust emission, the interpretation of this enhancement is a matter of controversy2. The origin of the non-thermal radiation that quasars emit at other wavebands is not understood; hence a non-thermal origin of their enhanced IR continua cannot be excluded. The existence of dust also has relevance to current discussions on the hydrogen emission-line ratios, for the weakness of the broad Lyα emission can possibly be explained by absorption on dust grains3,4. I present here circumstantial evidence that dust exists in the quasar 3C273, by demonstrating the existence of the 3.3 µm line in emission.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1

    Allen, D. A. Infrared, the New Astronomy (Keith Reid, Shaldon, Devon, 1975).

  2. 2

    Rieke, G. H. & Lebofsky, M. J. A. Rev. Astr. Astrophys. 17, 477–511 (1979).

  3. 3

    Baldwin, J. A. Mon. Not. R. astr. Soc. 178, 67P–74P (1978).

  4. 4

    Hyland, A. R., Becklin, E. E. & Neugebauer, G. Astrophys. J. Lett. 220, L73–L75 (1978).

  5. 5

    Russell, R. W., Soifer, B. T. & Merrill, K. M. Astrophys. J. 213, 66–70 (1977).

  6. 6

    Merrill, K. M. IAU Colloq. 42, 446–491 (1977).

  7. 7

    Allamandola, L. J., Greenberg, J. M. & Norman, C. A. Astr. Astrophys. 77, 66–74 (1979).

  8. 8

    Neugebauer, G., Oke, J. B., Becklin, E. E. & Matthews, K. Astrophys. J. 230, 79–94 (1979).

  9. 9

    Ferland, G. J. & Netzer, H. Astrophys. J. 229, 274–290 (1979).

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.