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Related papers: Galaxy groups and haloes in the SDSS-DR7

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We study the occupation statistics of galaxies in dark matter haloes using galaxy groups identified from the 2-degree Field Galaxy Redshift Survey with the halo-based group finder of Yang et al. The occupation distribution is considered…

Astrophysics · Physics 2009-11-10 Xiaohu Yang , H. J. Mo , Y. P. Jing , Frank C. van den Bosch

In this work we explore the possibility of applying machine learning methods designed for one-dimensional problems to the task of galaxy image classification. The algorithms used for image classification typically rely on multiple costly…

Astrophysics of Galaxies · Physics 2022-02-23 F. Tarsitano , C. Bruderer , K. Schawinski , W. G. Hartley

We present an analysis of the neutral hydrogen (HI) content and distribution of galaxies in groups as a function of their parent dark matter halo mass. The Arecibo Legacy Fast ALFA survey alpha.40 data release allows us, for the first time,…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Kelley M. Hess , Eric M. Wilcots

Imaging data from the Sloan Digital Sky Survey is used to measure the empirical size-richness relation for a large sample of galaxy clusters. Using population subtraction methods, we determine the radius at which the cluster galaxy number…

We develop a new method StarGO (Stars' Galactic Origin) to identify the galactic origins of halo stars using their kinematics. Our method is based on self-organizing map (SOM), which is one of the most popular unsupervised learning…

Astrophysics of Galaxies · Physics 2018-10-12 Zhen Yuan , Jiang Chang , Projjwal Banerjee , Jiaxin Han , Xi Kang , M. C. Smith

We applied a membership test based on the color similarity of group members to detect the discordant galaxies in small groups (quintets) that had been determined by the Friends-of-Friends (FoF) algorithm. Our method depends on the…

Astrophysics of Galaxies · Physics 2018-12-31 Ahmed M. Fouad , Z. Awad , A. A. Shaker , Z. M. Hayman

We investigate the performance of group finding algorithms that reconstruct galaxy groups from the positional information of tracer galaxies that are observed in redshift surveys carried out with multiplexed spectrographs. We use mock…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-28 Tobias J. Looser , Simon J. Lilly , Larry P. T. Sin , Bruno M. B. Henriques , Roberto Maiolino , Michele Cirasuolo

We use an empirical approach to model the stellar mass of galaxies according to their host dark-matter haloes and subhaloes ('HASH'), where each galaxy resides in a subhalo taken from a large N-body cosmological simulation. This approach…

Cosmology and Nongalactic Astrophysics · Physics 2012-09-05 Eyal Neistein , Sadegh Khochfar

Understanding the mechanisms that lead dense environments to host galaxies with redder colors, more spheroidal morphologies, and lower star formation rates than field populations remains an important problem. As most candidate processes…

Galaxies which fall into clusters as part of the same infall halo can retain correlations due to their shared origin. N-body simulations are used to study properties of such galaxy subgroups within clusters, including their richnesses and…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 J. D. Cohn

A new class of models of stellar discs is introduced and used to build a self-consistent model of our Galaxy. The model is defined by the parameters that specify the action-based distribution functions (DFs) f(J) of four stellar discs…

Astrophysics of Galaxies · Physics 2023-01-25 James Binney , Eugene Vasiliev

We investigate possible signatures of halo assembly bias for spectroscopically selected galaxy groups from the GAMA survey using weak lensing measurements from the spatially overlapping regions of the deeper, high-imaging-quality…

Using a nearest neighbor analysis, we construct a sample of void galaxies from the Sloan Digital Sky Survey (SDSS) and compare the photometric properties of these galaxies to the population of non-void (wall) galaxies. We trace the density…

Astrophysics · Physics 2009-11-10 Randall R. Rojas , Michael S. Vogeley , Fiona Hoyle , Jon Brinkmann

We use the first 25% of the DEEP2 Galaxy Redshift Survey spectroscopic data to identify groups and clusters of galaxies in redshift space. The data set contains 8370 galaxies with confirmed redshifts in the range 0.7 <= z <= 1.4, over one…

A full ring is a form of galaxy morphology that is not associated with a specific stage on the Hubble sequence. Digital sky surveys can collect many millions of galaxy images, and therefore even rare forms of galaxies are expected to be…

Astrophysics of Galaxies · Physics 2019-11-27 Lior Shamir

By comparing semi-analytic galaxy catalogues with data from the Sloan Digital Sky Survey (SDSS), we show that current galaxy formation models reproduce qualitatively the dependence of galaxy clustering and pairwise peculiar velocities on…

Astrophysics · Physics 2008-11-26 Cheng Li , Y. P. Jing , Guinevere Kauffmann , Gerhard Boerner , Xi Kang , Lan Wang

We study the relation between halo concentration and mass (c-M relation) using the Seventh and Eighth Data Release of the Sloan Digital Sky Survey (SDSS DR7 and DR8) galaxy catalogue. Assuming that the satellite galaxies follow the…

Astrophysics of Galaxies · Physics 2022-12-21 Qing Gu , Qi Guo , Tianchi Zhang , Wenting Wang , Quan Guo , Liang Gao

We utilize the galaxy shape catalogue from the first-year data release of the Subaru Hyper Suprime-cam Survey (HSC) to study the dark matter content of galaxy groups in the Universe using weak lensing. We use galaxy groups from the Galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-19 Divya Rana , Surhud More , Hironao Miyatake , Takahiro Nishimichi , Masahiro Takada , Aaron S. G. Robotham , Andrew M. Hopkins , Benne W. Holwerda

We present a deep-learning-based approach for identifying dark matter haloes in cosmological N-body simulations. Our framework consists of a volumetric Convolutional Neural Network to classify individual simulation particles as either halo…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-26 Soumadeep Maiti , Carlos M. Correa , Andrea Fiorilli , Andrés N. Ruiz , Dante J. Paz , Alejandro Pérez Fernández , Ariel G. Sánchez

We present a statistical analysis of halo emission for a sample of 1047 edge-on disk galaxies imaged in five bands by the Sloan Digital Sky Survey (SDSS). Stacking the homogeneously rescaled images of the galaxies, we can measure surface…

Astrophysics · Physics 2009-09-25 Stefano Zibetti , Simon D. M. White , Jon Brinkmann