Observations of the Hubble Deep Field with the Infrared Space Observatory - III. Source counts and P(D) analysis

S. J. Oliver, P. Goldschmidt, A. Franceschini, S. B.G. Serjeant, A. Efstathiou, A. Verma, C. Gruppioni, N. Eaton, R. G. Mann, B. Mobasher, C. P. Pearson, M. Rowan-Robinson, T. J. Sumner, L. Danese, D. Elbaz, E. Egami, M. Kontizas, A. Lawrence, R. McMahon, H. U. Norgaard-NielsenI. Perez-Fournon, J. I. Gonzalez-Serrano

Research output: Contribution to journalArticlepeer-review

68 Scopus citations


We present source counts at 6.7 and 15 μm from our maps of the Hubble Deep Field (HDF) region, reaching 38.6 μJy at 6.7 μm and 255 μJy at 15 μm. These are the first ever extragalactic number counts to be presented at 6.7 μm, and are three decades fainter than IRAS at 12 μm. Both source counts and a P(D) analysis suggest that we have reached the Infrared Space Obsen'atory (ISO) confusion limit at 15 μm: this will have important implications for future space missions. These data provide an excellent reference point for other ongoing ISO surveys. A no-evolution model at 15 μm is ruled out at > 3σ, while two models which fit the steep IRAS 60-μm counts are acceptable. This provides important confirmation of the strong evolution seen in IRAS surveys. One of these models can then be ruled out from the 6.7-μm data.

Original languageEnglish (US)
Pages (from-to)471-481
Number of pages11
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
StatePublished - 1997
Externally publishedYes


  • Galaxies: Evolution
  • Galaxies: Formation
  • Galaxies: Seyfert galaxies: Starburst
  • Infrared: Galaxies
  • Surveys

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'Observations of the Hubble Deep Field with the Infrared Space Observatory - III. Source counts and P(D) analysis'. Together they form a unique fingerprint.

Cite this