Abstract
Ground-based counts and colours of faint galaxies in the U and R bands in one field at high Galactic latitude are presented. Integrated over flux, a total of 1.2 × 10 5 source deg -2 are found to U = 25.5 mag and 6.3 × 10 5 source deg -2 to R = 21 mag, with d log N/dm ∼ 0.5 in the U band and d log N/dm ∼ 0.3 in the R band. Consistent with these number-magnitude curves, sources become bluer with increasing magnitude to median U - R = 0.6 mag at 24 < U < 25 mag and U - R = 1.2 mag at 25 < R < 26 mag. Because the Lyman break redshifts into the U band at z ≈ 3, at least 1.2 × 10 5 source deg -2 must be at redshifts z < 3. Measurable U-band fluxes of 73 per cent of the 6.3 × 10 5 source deg -2 suggest that the majority of these also lie at z < 3. These results require an enormous space density of objects in any cosmological model.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 404-410 |
| Number of pages | 7 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 288 |
| Issue number | 2 |
| State | Published - 1997 |
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Keywords
- Cosmology: observations
- Galaxies: fundamental parameters
- Galaxies: photometry
- Ultraviolet: galaxies
ASJC Scopus subject areas
- Space and Planetary Science
Cite this
Counts and colours of faint galaxies in the U and R bands. / Hogg, David W.; Pahre, Michael A.; McCarthy, James K.; Cohen, Judith G.; Blandford, Roger; Smail, Ian; Soifer, B. T.
In: Monthly Notices of the Royal Astronomical Society, Vol. 288, No. 2, 1997, p. 404-410.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Counts and colours of faint galaxies in the U and R bands
AU - Hogg, David W.
AU - Pahre, Michael A.
AU - McCarthy, James K.
AU - Cohen, Judith G.
AU - Blandford, Roger
AU - Smail, Ian
AU - Soifer, B. T.
PY - 1997
Y1 - 1997
N2 - Ground-based counts and colours of faint galaxies in the U and R bands in one field at high Galactic latitude are presented. Integrated over flux, a total of 1.2 × 10 5 source deg -2 are found to U = 25.5 mag and 6.3 × 10 5 source deg -2 to R = 21 mag, with d log N/dm ∼ 0.5 in the U band and d log N/dm ∼ 0.3 in the R band. Consistent with these number-magnitude curves, sources become bluer with increasing magnitude to median U - R = 0.6 mag at 24 < U < 25 mag and U - R = 1.2 mag at 25 < R < 26 mag. Because the Lyman break redshifts into the U band at z ≈ 3, at least 1.2 × 10 5 source deg -2 must be at redshifts z < 3. Measurable U-band fluxes of 73 per cent of the 6.3 × 10 5 source deg -2 suggest that the majority of these also lie at z < 3. These results require an enormous space density of objects in any cosmological model.
AB - Ground-based counts and colours of faint galaxies in the U and R bands in one field at high Galactic latitude are presented. Integrated over flux, a total of 1.2 × 10 5 source deg -2 are found to U = 25.5 mag and 6.3 × 10 5 source deg -2 to R = 21 mag, with d log N/dm ∼ 0.5 in the U band and d log N/dm ∼ 0.3 in the R band. Consistent with these number-magnitude curves, sources become bluer with increasing magnitude to median U - R = 0.6 mag at 24 < U < 25 mag and U - R = 1.2 mag at 25 < R < 26 mag. Because the Lyman break redshifts into the U band at z ≈ 3, at least 1.2 × 10 5 source deg -2 must be at redshifts z < 3. Measurable U-band fluxes of 73 per cent of the 6.3 × 10 5 source deg -2 suggest that the majority of these also lie at z < 3. These results require an enormous space density of objects in any cosmological model.
KW - Cosmology: observations
KW - Galaxies: fundamental parameters
KW - Galaxies: photometry
KW - Ultraviolet: galaxies
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UR - http://www.scopus.com/inward/citedby.url?scp=0001315616&partnerID=8YFLogxK
M3 - Article
VL - 288
SP - 404
EP - 410
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 2
ER -