Deep galaxy counts in the K band with the Keck telescope
Deep galaxy counts in the K band with the Keck telescope
复制标题
使用凯克望远镜计算 K 波段的深部星系
DOI：
10.1086/187703
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
J. Nelson
中科院分区：
文献类型：
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作者：
S. Djorgovski;B. Soifer;M. Pahre;J. Larkin;J. Smith;G. Neugebauer;I. Smail;K. Matthews;D. Hogg;R. Blandford;J. Cohen;W. Harrison;J. Nelson
我们目前的深星系计数在K（12.2微米）波段，在W。M.凯克10米望远镜。这些数据达到了极限星等K，大约24等，比迄今为止最深的K波段图像深5倍。计数在三个小的（约1分钟），广泛分离的高纬度领域进行。广泛的蒙特卡罗测试被用来获得完整性校正和最大限度地减少光度偏差。计数继续上升，没有周转的迹象，下降到我们数据的极限，在K = 20和24马格之间的对数斜率为d log N/dm = 0.315 +/- 0.02。这意味着累积的表面密度约为5 x 10^5个星系/平方度，或整个天空约为2 x 10^10，我们的计算结果与考伊及其合作者的夏威夷深度测量结果一致，尽管略低于后者;差异可能是由于孔径校正的微小差异。我们将我们的计数与一些可用的理论预测进行比较。这些数据不需要具有高Omega_0值的模型，但可以很好地拟合没有（或很少）演化的模型和具有低Omega_0值的宇宙学。考虑到模型中的不确定性，仅从计数对Omega_0的值施加有用的约束可能为时过早。光学到红外线的颜色计算，使用CCD数据获得先前在帕洛玛。我们发现了一些（r-K）大约大于5等或（i-K）大约大于5等的红星系;这些可能是z约为1的椭圆星系。虽然在我们的计数星系的红移分布仍然是未知的，达到的通量极限将使我们能够检测到未遮蔽的L_* 星系的大量红移（z大于3？）
We present deep galaxy counts in the K (⋋ 2.2 micrometer) band, obtained at the W. M. Keck 10 m telescope. The data reach limiting magnitudes K approximately 24 mag, about 5 times deeper than the deepest published K-band images to date. The counts are performed in three small (approximately 1 min), widely separated high-latitude fields. Extensive Monte Carlo tests were used to derive the completeness corrections and minimize photometric biases. The counts continue to rise, with no sign of a turnover, down to the limits of our data, with the logarithmic slope of d log N/dm = 0.315 +/- 0.02 between K = 20 and 24 mag. This implies a cumulative surface density of approximately 5 x 10^5 galaxies/sq deg, or approximately 2 x 10^10 over the entire sky, down to K = 24 mag. Our counts are in good agreement with, although slightly lower than, those from the Hawaii Deep Survey by Cowie and collaborators; the discrepancies may be due to the small differences in the aperture corrections. We compare our counts with some of the available theoretical predictions. The data do not require models with a high value of Omega_0, but can be well fitted by models with no (or little) evolution, and cosmologies with a low value of Omega_0. Given the uncertainties in the models, it may be premature to put useful constrains on the value of Omega_0 from the counts alone. Optical-to-IR colors are computed, using CCD data obtaind previously at Palomar. We find a few red galaxies with (r-K) approximately greater than 5 mag, or (i-K) approximately greater than 5 mag; these may be ellipticals at z approximately 1. While the redshift distribution of galaxies in our counts is still unknown, the flux limits reached would allow us to detect unobscured L_* galaxies out to substantial redshifts (z greater than 3?)