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Related papers: ORCA: The Overdense Red-sequence Cluster Algorithm

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We directly compare X-ray and optical techniques of cluster detection by combining SDSS photometric data with a wide-field ($\sim 1.8$ deg$^{2}$) XMM-{\em Newton} survey in the North Galactic Pole region. The optical cluster detection…

Mapping galaxies at low Galactic latitudes and determining their clustering status are fundamental steps in defining the large-scale structure in the nearby Universe. The VVV Near-IR Galaxy Catalogue (VVV NIRGC) allows us to explore this…

Galaxy clusters can be detected as surface brightness enhancements in smoothed optical surveys. This method does not require individual galaxies to be identifiable, and enables clusters to be detected out to surprisingly high redshifts, as…

Astrophysics · Physics 2009-11-07 Matthias Bartelmann , Simon D. M. White

Clustering of high-dimensional data sets is a growing need in artificial intelligence, machine learning and pattern recognition. In this paper, we propose a new clustering method based on a combinatorial-topological approach applied to…

Machine Learning · Computer Science 2025-03-12 Mauricio Toledo-Acosta , Luis Ángel Ramos-García , Jorge Hermosillo-Valadez

We develop the Blooming Tree Algorithm, a new technique that uses spectroscopic redshift data alone to identify the substructures and the surrounding groups of galaxy clusters, along with their member galaxies. Based on the estimated…

Astrophysics of Galaxies · Physics 2018-06-21 Heng Yu , Antonaldo Diaferio , Ana Laura Serra , Marco Baldi

As a step towards our understanding of galaxy evolution and for testing predictions of cosmological models we started a survey for galaxy clusters intending to identify candidates out to redshifts of ~1.5: HIROCS (= Heidelberg…

Astrophysics · Physics 2009-11-10 S. Falter , H. -J. Roeser , H. Hippelein , E. Bell , C. Wolf

We present multi-wavelength studies of optically-defined merging clusters, based on the Hyper Suprime-Cam Subaru Strategic Program. Luminous red galaxies, tracing cluster mass distributions, enable to identify cluster subhalos at various…

RedGOLD searches for red-sequence galaxy overdensities while minimizing contamination from dusty star-forming galaxies. It imposes an NFW profile and calculates cluster detection significance and richness. We optimize these latter two…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-15 Rossella Licitra , Simona Mei , Anand Raichoor , Thomas Erben , Hendrik Hildebrandt

We identify a sample of 324 red and 273 blue face-on spiral galaxies selected from 115 low-redshift (0.014 < z < 0.18) galaxy clusters imaged with CFHT+MegaCam in u- and r-band, KPNO 0.9-meter 2TKA and MOSAIC 8K camera in B and Rc, and…

Recent large-scale galaxy spectroscopic surveys, such as the Sloan Digital Sky Survey (SDSS), enable us to execute a systematic, relatively-unbiased search for galaxy clusters. Such surveys make it possible to measure the 3-d distribution…

Astrophysics · Physics 2009-11-13 Joo H. Yoon , Kevin Schawinski , Yun-Kyeong Sheen , Chang H. Ree , Sukyoung K. Yi

We have developed a new method, K2, optimized for the detection of galaxy clusters in multicolor images. Based on the Red Sequence approach, K2 detects clusters using simultaneous enhancements in both colors and position. The detection…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Karun Thanjavur , Jon Willis , David Crampton

We present an innovative and widely applicable approach for the detection and classification of stellar clusters, developed for the PHANGS-HST Treasury Program, an $NUV$-to-$I$ band imaging campaign of 38 spiral galaxies. Our pipeline first…

The census of massive clusters of galaxies in the local Universe is almost complete, thanks to their prominent observational signatures at X-ray, optical, and sub-mm wavelengths. Nevertheless, a number of such systems are likely to be…

We present CluSTAR-ND, a fast hierarchical galaxy/(sub)halo finder that produces {\bf Clu}stering {\bf S}tructure via {\bf T}ransformative {\bf A}ggregation and {\bf R}ejection in {\bf N}-{\bf D}imensions. It is designed to improve upon…

Astrophysics of Galaxies · Physics 2022-06-29 William H. Oliver , Pascal J. Elahi , Geraint F. Lewis

We have identified 335 galaxy cluster and group candidates spanning 0<z<2, using a 4.5um selected sample of galaxies in a 7.25 deg^2 region in the Spitzer/IRAC Shallow Survey. Using full redshift probability distributions for all galaxies,…

In the past decade, HCI surveys provided new insights about the frequency and properties of substellar companions at separation larger than 5 au. In this context, our study aims to detect and characterise potential exoplanets and brown…

Earth and Planetary Astrophysics · Physics 2022-10-05 C. -H. Dahlqvist , J. Milli , O. Absil , F. Cantalloube , L. Matra , E. Choquet , C. del Burgo , J. P. Marshall , M. Wyatt , S. Ertel

Star clusters are often hard to find, as they may lie in a dense field of background objects or, because in the case of embedded clusters, they are surrounded by a more dispersed population of young stars. This paper discusses four…

Astrophysics of Galaxies · Physics 2011-02-16 S. Schmeja

We present the first results of a serendipitous search for clusters of galaxies in deep ROSAT-PSPC pointed observations at high galactic latitude. The survey is being carried out using a Wavelet based Detection Algorithm which is not biased…

Astrophysics · Physics 2016-08-30 P. Rosati , R. Della Ceca , R. Burg , C. Norman , R. Giacconi

We analyse the nature of a sample of stellar overdensities that we found projected on the Carina complex. This study is based on 2MASS photometry and involves the photometry decontamination of field stars, elaboration of intrinsic…

Astrophysics of Galaxies · Physics 2018-02-07 R. A. P. Oliveira , E. Bica , C. Bonatto

We build upon Ordering Points To Identify Clustering Structure (OPTICS), a hierarchical clustering algorithm well-known to be a robust data-miner, in order to produce Halo-OPTICS, an algorithm designed for the automatic detection and…

Astrophysics of Galaxies · Physics 2021-01-06 William H. Oliver , Pascal J. Elahi , Geraint F. Lewis , Chris Power
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