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Several UV and near-infrared color selection methods have identified galaxies at z = 1-3. Since each method suffers from selection biases, we have applied three leading techniques (Lyman break, BX/BM, and BzK selection) simultaneously in…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-28 Chun Ly , Matthew A. Malkan , Masao Hayashi , Kentaro Motohara , Nobunari Kashikawa , Kazuhiro Shimasaku , Tohru Nagao , Celestine Grady

We investigate the evolution of the galaxy two point correlation function (CF) over a wide redshift range, 0.2 < z < 3. For the first time the systematic analysis covers the redshifts above 1 - 1.5. The catalogue of ~250000 galaxies with i+…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-09 A. M. Soltan , M. J. Chodorowski

We obtained GALEX FUV, NUV, and Spitzer/IRAC 3.6$\mu$m photometry for > 2000 galaxies, available for 90% of the S4G sample. We find a very tight "GALEX Blue Sequence (GBS)" in the (FUV-NUV) versus (NUV-[3.6]) color-color diagram which is…

We have analyzed the distributions in the color-magnitude diagram (CMD) of a large sample of face-on galaxies to minimize the effect of dust extinctions on galaxy color. About 300 thousand galaxies with $log(a/b) < $ 0.2 and redshift $z <…

Astrophysics of Galaxies · Physics 2014-05-07 Shuo-Wen Jin , Qiusheng Gu , Song Huang , Yong Shi , Long-Long Feng

We present a research of morphologies, spectra and environments of $\approx$ 2350 "green valley" galaxies at $0.2<z<1.0$ in the COSMOS field. The bimodality of dust-corrected \nuvr\ color is used to define "green valley" (thereafter, GV),…

Astrophysics of Galaxies · Physics 2015-06-17 Zhizheng Pan , Xu Kong , Lulu Fan

We present measurements of the higher-order clustering of red and blue galaxies as a function of scale and luminosity made from the two-degree field galaxy redshift survey (2dFGRS). We use a counts-in-cells analysis to estimate the volume…

Astrophysics · Physics 2008-11-26 Darren J. Croton , Peder Norberg , Enrique Gaztanaga , Carlton M. Baugh

Precision-era optical cluster cosmology calls for a precise definition of the red sequence (RS), consistent across redshift. To this end, we present the Red Dragon algorithm: an error-corrected multivariate Gaussian mixture model (GMM).…

Cosmology and Nongalactic Astrophysics · Physics 2022-08-03 William K. Black , August Evrard

Using the photometric population prediction method {\bf Red Dragon}, we characterize the Red Sequence (RS) and Blue Cloud (BC) of DES galaxies in the COSMOS field. Red Dragon (RD) uses a redshift-evolving, error-corrected Gaussian mixture…

Astrophysics of Galaxies · Physics 2024-04-05 William K. Black , August E. Evrard

The colour bimodality of galaxies provides an empirical basis for theories of galaxy evolution. However, the balance of processes that begets this bimodality has not yet been constrained. A more detailed view of the galaxy population is…

We describe a large sample of 598 galaxy clusters and rich groups discovered in the data of the Faint Sky Variability Survey. The clusters have been identified using a fully automated, semi-parametric technique based on a maximum likelihood…

Astrophysics · Physics 2009-11-11 Ilona K. Soechting , Mark E. Huber , Roger G. Clowes , Steve B. Howell

Using the 'k-means' cluster analysis algorithm, we carry out an unsupervised classification of all galaxy spectra in the seventh and final Sloan Digital Sky Survey data release (SDSS/DR7). Except for the shift to restframe wavelengths, and…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-16 J. Sanchez Almeida , J. A. L. Aguerri , C. Munoz-Tunon , A. de Vicente

In this work, decision tree learning algorithms and fuzzy inferencing systems are applied for galaxy morphology classification. In particular, the CART, the C4.5, the Random Forest and fuzzy logic algorithms are studied and reliable…

Astrophysics of Galaxies · Physics 2010-06-02 Adam Gauci , Kristian Zarb Adami , John Abela

We measure the two-point angular correlation function of a sample of 4,289,223 galaxies with r < 19.4 mag from the Sloan Digital Sky Survey as a function of photometric redshift, absolute magnitude and colour down to M_r - 5log h = -14 mag.…

Although the optical colour-magnitude diagram of galaxies allows one to select red sequence objects, neither can it be used for galaxy classification without additional observational data such as spectra or high-resolution images, nor to…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Igor Chilingarian , Ivan Zolotukhin

Few galaxies have been found between the redshift ranges z < ~1 probed by magnitude-limited surveys and z > ~3 probed by Lyman-break surveys. Comparison of galaxy samples at lower and higher redshift suggests that large numbers of stars…

We present a new method to classify the broad band optical-NIR spectral energy distributions (SEDs) of galaxies using three shape parameters (super-colours) based on a Principal Component Analysis of model SEDs. As well as providing a…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Vivienne Wild , Omar Almaini , Michele Cirasuolo , Jim Dunlop , Ross McLure , Rebecca Bowler , Joao Ferreira , Emma Bradshaw , Robert Chuter , Will Hartley

We measure the colour evolution and quenching time-scales of $z=1.0-1.8$ galaxies across the green valley. We derive rest-frame $NUVrK$ colours and select blue-cloud, green-valley and red-sequence galaxies from the spectral energy…

The distribution of galaxies has been studied to show the difference between the blue cloud and red sequence and to define the green valley region. However, there are still many open questions regarding the importance of the green valley…

Astrophysics of Galaxies · Physics 2021-07-14 Beatrice Nyiransengiyumva , Mirjana Povic , Pheneas Nkundabakura , Antoine Mahoro

We present a catalogue of 99 candidate clusters and groups of galaxies in the redshift range 0.1 < z_{phot} < 1.3 discovered in the Spitzer First Look Survey (FLS). The clusters are selected by their R - 3.6um galaxy color-magnitude…

Astrophysics · Physics 2009-11-13 Adam Muzzin , Gillian Wilson , Mark Lacy , H. K. C. Yee , S. A. Stanford