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We present a maximum-likelihood analysis of galaxy-galaxy lensing effects in galaxy clusters and in the field. The aim is to determine the accuracy and robustness of constraints that can be obtained on galaxy halo properties in both…

Astrophysics · Physics 2009-11-10 Marceau Limousin , Jean Paul Kneib , Priyamvada Natarajan

We present a novel method to retrieve the chemical structure of galaxies using integral field spectroscopy data through the stellar Metallicity Distribution Function (MDF). This is the probability distribution of observing stellar…

Astrophysics of Galaxies · Physics 2020-10-14 A. Mejía-Narváez , S. F. Sánchez , E. A. D. Lacerda , L. Carigi , L. Galbany , B. Husemann , R. García-Benito

The estimation and utilization of photometric redshift probability density functions (photo-$z$ PDFs) has become increasingly important over the last few years and currently there exist a wide variety of algorithms to compute photo-$z$'s,…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-05 M. Carrasco Kind , R. J. Brunner

Historical observations of severe weather and simulated severe weather environments (i.e., features) from the Global Ensemble Forecast System v12 (GEFSv12) Reforecast Dataset (GEFS/R) are used in conjunction to train and test random forest…

Atmospheric and Oceanic Physics · Physics 2022-12-19 Aaron J. Hill , Russ S. Schumacher , Israel Jirak

Measuring environment for large numbers of distant galaxies is still an open problem, for which we need galaxy positions and redshifts. Photometric redshifts are more easily available for large numbers of galaxies, but at the price of…

Astrophysics of Galaxies · Physics 2016-01-06 Nicola Malavasi , Lucia Pozzetti , Olga Cucciati , Sandro Bardelli , Andrea Cimatti

We provide classifications for all 143 million non-repeat photometric objects in the Third Data Release of the Sloan Digital Sky Survey (SDSS) using decision trees trained on 477,068 objects with SDSS spectroscopic data. We demonstrate that…

Astrophysics · Physics 2008-11-26 Nicholas M. Ball , Robert J. Brunner , Adam D. Myers , David Tcheng

The joint probability distribution function (PDF) of the density within multiple concentric spherical cells is considered. It is shown how its cumulant generating function can be obtained at tree order in perturbation theory as the Legendre…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-19 Francis Bernardeau , Christophe Pichon , Sandrine Codis

We present the dust mass function (DMF) of 15,750 galaxies with redshift $z< 0.1$, drawn from the overlapping area of the GAMA and {\it H-}ATLAS surveys. The DMF is derived using the density corrected $V_{\rm max}$ method, where we estimate…

We present a photometric redshift (photo-$z$) estimation technique for galaxies in the P\lowercase{an}-STARRS1 (PS1) $3\pi $ survey. Specifically, we train and test a regression and a classification Random-Forest (RF) models using…

Astrophysics of Galaxies · Physics 2021-05-28 A. Baldeschi , M. Stroh , R. Margutti , T. Laskar , A. Miller

The detection and characterization of filamentary structures in the cosmic web allows cosmologists to constrain parameters that dictates the evolution of the Universe. While many filament estimators have been proposed, they generally lack…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-07 Yen-Chi Chen , Shirley Ho , Peter E. Freeman , Christopher R. Genovese , Larry Wasserman

We present a novel approach to photometric redshifts, one that merges the advantages of both the template fitting and empirical fitting algorithms, without any of their disadvantages. This technique derives a set of templates, describing…

Astrophysics · Physics 2009-10-31 I. Csabai , A. J. Connolly , A. S. Szalay , T. Budavari

We present and compare in this paper new photometric redshift catalogs of the galaxies in three public fields: the NTT Deep Field, the HDF-N and the HDF-S. Photometric redshifts have been obtained for thewhole sample, by adopting a $\chi^2$…

Astrophysics · Physics 2009-10-31 A. Fontana , S. D'Odorico , F. Poli , E. Giallongo , S. Arnouts , S. Cristiani , A. Moorwood , P. Saracco

We present a catalogue of galaxy photometric redshifts for the Sloan Digital Sky Survey (SDSS) Data Release 12. We use various supervised learning algorithms to calculate redshifts using photometric attributes on a spectroscopic training…

Instrumentation and Methods for Astrophysics · Physics 2019-04-23 Kenny Chong , Abel Yang

The extensive catalog of $\gamma$-ray selected flat-spectrum radio quasars (FSRQs) produced by \emph{Fermi} during a four-year survey has generated considerable interest in determining their $\gamma$-ray luminosity function (GLF) and its…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-31 Houdun Zeng , Fulvio Melia , Li Zhang

Traditional photometric redshift methods use only color information about the objects in question to estimate their redshifts. This paper introduces a new method utilizing colors, luminosity, surface brightness, and radial light profile to…

Astrophysics · Physics 2008-11-26 James J. Wray , James E. Gunn

To understand the nature of the accelerated expansion of the Universe, we need to combine constraints on the expansion rate and growth of structure. The growth rate is usually extracted from three dimensional galaxy maps by exploiting the…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-12 Carolina Cuesta-Lazaro , Baojiu Li , Alexander Eggemeier , Pauline Zarrouk , Carlton M. Baugh , Takahiro Nishimichi , Masahiro Takada

The second mission of the NASA Kepler satellite, K2, has collected hundreds of thousands of lightcurves for stars close to the ecliptic plane. This new sample could increase the number of known pulsating stars and then improve our…

Solar and Stellar Astrophysics · Physics 2019-06-25 A. Le Saux , L. Bugnet , S. Mathur , S. N. Breton , R. A. Garcia

Studies of the distribution and evolution of galaxies are of fundamental importance to modern cosmology; these studies, however, are hampered by the complexity of the competing effects of spectral and density evolution. Constructing a…

Astrophysics · Physics 2009-10-31 R. J. Brunner , A. J. Connolly , A. S. Szalay