Galaxy number counts - III. Deep CCD observations to B=27.5 mag

Metcalfe, N.; Shanks, T.; Fong, R.; Roche, N.

doi:10.1093/mnras/273.2.257

Cited by 135 publications

(153 citation statements)

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“…There are large field-to-field variations in the random-field K s -band counts, and even though the counts in the quasar fields appear to lie above the literature averages at fainter K s magnitudes, they are still consistent with the counts from the surveys by, e.g., Soifer et al (1994), Moustakas et al (1997), and Maihara et al (2001). We also find that the R-band number counts are consistent with the counts in the general field (Metcalfe et al 1995;Hogg et al 1997). Overplotted in Figure 5 are also the number counts of EROs in our fields, demonstrating, as expected, that non-ERO galaxies clearly dominate at all magnitudes.…”

Section: K S -Band Countssupporting

confidence: 84%

Overdensities of Extremely Red Objects in the Fields of High-Redshift Radio-Loud Quasars

et al. 2003

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We have examined the occurrence of extremely red objects (EROs) in the fields of 13 luminous quasars (11 radio-loud and two radio-quiet) at 1.8 < z < 3.0. The average surface density of K s 19 mag EROs is 2-3 times higher than in large, random-field surveys, and the excess is significant at the %3 level even after taking into account that the ERO distribution is highly inhomogeneous. This is the first systematic investigation of the surface density of EROs in the fields of radio-loud quasars above z % 2 and shows that a large number of the fields contain clumps of EROs, similar to what is seen only in the densest areas in random-field surveys. The high surface densities and angular distribution of EROs suggest that the excess originates in high-redshift galaxy concentrations, possibly young clusters of galaxies. The fainter EROs at K s e 19 mag show some evidence of being more clustered in the immediate 20 00 region around the quasars, suggesting an association with the quasars. Comparing with predictions from spectral synthesis models, we find that if the K s % 19 mag ERO excess is associated with the quasars at z % 2, their magnitudes are typical of eL* passively evolving galaxies formed at z % 3.5 ( m = 0.3, Ã = 0.7, and H 0 = 70 km s À1 Mpc À1 ). Another interpretation of our results is that the excess originates in concentrations of galaxies at z % 1 lying along the line of sight to the quasars. If this is the case, the EROs may be tracing massive structures responsible for a magnification bias of the quasars.

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Section: K S -Band Countssupporting

confidence: 84%

Overdensities of Extremely Red Objects in the Fields of High-Redshift Radio-Loud Quasars

et al. 2003

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“…SpeciÐcally, we have multiplied GFÏs S0 counts by 73/57 and, in order to preserve the total counts, we have taken the di †erential counts from both the E and Sp populations according to the relative percentages given in°3 (75% and 25%, respectively). (iii) The Ðeld contamination was determined from the galaxy number counts given by Metcalfe et al (1995) and the breakdown into morphological classes (E : S0 : Sp \ 18 : 27 : 56) was computed for our limiting magnitudes at z D 0.2 from the Ðts to the di †erential number counts of the Medium Deep Survey (S97). The background assumed is listed for each cluster in Table 5, which is available the on-line edition of the Journal.…”

Section: Evolution In Morphological Contentmentioning

confidence: 99%

The Evolution of the Galactic Morphological Types in Clusters

Fasano¹,

Poggianti²,

Couch³

et al. 2000

ApJ

301

322

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The morphological types of galaxies in nine clusters in the redshift range are derived 0.1 [ z [ 0.25 from very good seeing images taken at the NOT and the La SillaÈDanish telescopes, with all galaxies at and within the central D1 Mpc2 area being classiÐed. With the purpose of investigating the M V \ [20 evolution of the fraction of di †erent morphological types with redshift, we compare our results with the morphological content of nine distant clusters studied by the MORPHS group, Ðve clusters observed with HST /WFPC2 at redshift z \ 0.2È0.3, and DresslerÏs large sample of nearby clusters. After having checked the reliability of our morphological classiÐcation both in an absolute sense and relative to the MORPHS scheme, we analyze the relative occurrence of elliptical, S0, and spiral galaxies as a function of the cluster properties and redshift. We Ðnd a large intrinsic scatter in the S0/E ratio, mostly related to the cluster morphology. In particular, in our cluster sample, clusters with a high concentration of ellipticals display a low S0/E ratio and, vice versa, low concentration clusters have a high S0/E. At the same time, the trend of the morphological fractions (%EÏs, %S0Ïs, %SpÏs) and of the S0/E and S0/Sp ratios with redshift clearly points to a morphological evolution : as the redshift decreases, the S0 population tends to grow at the expense of the spiral population, whereas the frequency of EÏs remains almost constant. We also analyze the morphology-density (MD) relation in our clusters and Ðnd thatÈsimilarly to higher redshift clustersÈa good MD relation exists in the high-concentration clusters, while it is absent in the less concentrated clusters. Finally, the comparison of the MD relation in our clusters with that of the MORPHS sample suggests that the transformation of spirals into S0 galaxies becomes more efficient with decreasing local density.

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“…e-mail: swagner@lsw.uni-heidelberg.de incorporating luminosity evolution have been found to explain the number counts down to the faintest levels (Metcalfe et al 1995;Pozzetti et al 1996). As pointed out by Gardner (1998) however, the colour distribution contains more information about the state of evolution than the pure number counts, and the modeling of the colour distributions is a good test for the evolution models which explain number counts in individual filters.…”

Section: Modelsmentioning

confidence: 99%

“…3 and 4 we compare counts of galaxies at the NEP with published counts from other surveys in B j and R, respectively. The reference data are from Bertin & Dennefeld (1997), Jones et al (1991), Huang et al (2001) and Metcalfe et al (1991Metcalfe et al ( , 1995. All B j -counts except Huang et al (2001) were either performed in a B j -filter or transformed to B j using equations given by the authors.…”

Section: Number Densities Of Galaxiesmentioning

confidence: 99%

A wide field survey at the Northern Ecliptic Pole

Kümmel

Wagner²

2001

A&A

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Abstract. We present a medium deep survey carried out in the three filters Bj, R and K. The survey covers homogeneously the central square degree around the Northern Ecliptic Pole (NEP) down to a completeness limit (95%) of 24.25, 23.0 and 17.5 mag in Bj, R and K, respectively. While the near infrared data have been presented in the first paper of this series, here we concentrate on the optical data and the results based on the combined BjRK-data. The unique combination of area and depth in our survey allows to perform a variety of investigations based on homogeneous material covering more than ten magnitudes in apparent brightness. We analyze the number counts for point-like and extended sources in Bj and R to determine the slopes in d log N/dm and to test for possible breaks therein. While we can confirm the slopes found in previous works with a higher statistical significance, the largest uncertainty remaining for the amplitudes is galactic extinction. We determine the colour distributions of galaxies in Bj − R and R − K down to Bj = 24.0 and K = 18.0 mag, respectively. The distributions in both colours are modeled using galaxy spectral evolution synthesis. We demonstrate that the standard models of galaxy evolution are unable to reproduce the steady reddening trend in R − K despite flawless fits to the colour distributions in the optical (Bj −R). The BjRK data collected over a large area provides the opportunity to select rare objects like candidates for high-redshift galaxies and extremely red objects (EROs, R − K > 5.0) and to determine their surface density. Our EROs are selected at an intermediate magnitude range and contain contribution from both galactic as well as extragalactic sources. At K < 16.5 mag, where a morphological classification is possible, the stellar component dominates the sample.

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Galaxy number counts - III. Deep CCD observations to B=27.5 mag

Cited by 135 publications

References 0 publications

Overdensities of Extremely Red Objects in the Fields of High-Redshift Radio-Loud Quasars

Overdensities of Extremely Red Objects in the Fields of High-Redshift Radio-Loud Quasars

The Evolution of the Galactic Morphological Types in Clusters

A wide field survey at the Northern Ecliptic Pole

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