J/ApJ/475/445 VIK photometry of faint field galaxies (Moustakas+ 1997)
Colors and K-band counts of extremely faint field galaxies. Moustakas L.A., Davis M., Graham J.R., Silk J., Peterson B.A., Yoshii Y. <Astrophys. J. 475, 445 (1997)> =1997ApJ...475..445M (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, photometry ; Photometry, infrared Keywords: cosmology: observations - galaxies: evolution - galaxies: photometry - galaxies: statistics - infrared: galaxies Abstract: We combine deep K-band (W. M. Keck Telescope) with V- and I-band (New Technology Telescope) observations of two "blank" high Galactic latitude fields, surveying a total of ∼2arcmin2. The K-band number-magnitude counts continue to rise above K∼22mag, reaching surface densities of few x105deg-2. The slope for the galaxy counts is approximately [dlog(N)/dmag].deg-2=0.23±0.02 over the range 18-23mag. While this slope is consistent with other recent deep K-band surveys, there is a definite scatter in the normalisations by about a factor of 2. In particular, our normalisation is ∼2x greater than the galaxy counts reported by Djorgovski et al. in 1995 (1995ApJ...438L..13D). Optical near-infrared color-magnitude and color-color diagrams for all objects detected in the V+I+K image are plotted and discussed in the context of grids of Bruzual-Charlot isochrone synthesis galaxy evolutionary models. The colors of most of the observed galaxies are consistent with a population drawn from a broad redshift distribution. A few galaxies at K∼19-20 are red in both colors (V-I>3; I-K>2, consistent with being early-type galaxies having undergone a burst of star formation at z>5 and viewed at z∼1. At K>20, we find several (approximately eight) "red outlier" galaxies with I-K>4 and V-I<2.5, whose colors are difficult to mimic by a single evolving or nonevolving stellar population at any redshift unless they either have quite low metallicity or are highly reddened. We compare the data against the evolutionary tracks of second-burst ellipticals and against a grid of models that does not constrain galaxy ages to a particular formation redshift. The red outliers' surface density is several per square arcminute, which is so high that they are probably common objects of low luminosity L<L*. Whether these are low-metallicity, dusty dwarf galaxies, or old galaxies at high redshift, they are curious and merit spectroscopic follow-up. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table4 57 116 Object catalog for field I table5 57 111 Object catalog for field II
Byte-by-byte Description of file: table4 table5
Bytes Format Units Label Explanations
1- 2 I2 h RAh Right ascension (1950) 4- 5 I2 min RAm Right ascension (1950) 7- 11 F5.2 s RAs Right ascension (1950) 14 A1 --- DE- Declination sign 15- 16 I2 deg DEd Declination (1950) 18- 19 I2 arcmin DEm Declination (1950) 21- 25 F5.2 arcsec DEs Declination (1950) 28- 32 F5.1 arcsec xpos X position (1) 35- 39 F5.1 arcsec ypos Y position (1) 42- 45 F4.1 mag Vmag V magnitude (2) 48- 51 F4.1 mag Imag I magnitude (2) 54- 57 F4.1 mag Kmag K magnitude
Note (1): North is up, East is left. Note (2): When the magnitude is '0.0', no reliable value.
History: Prepared via OCR at CDS.
(End) James Marcout, Patricia Bauer [CDS] 24-Oct-1997
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