English
Related papers

Related papers: Redshift prediction of Fermi-LAT gamma-ray sources…

200 papers

We predict the redshift distribution of long Gamma-Ray Bursts (GRBs) with Monte Carlo simulations. Our improved analysis constrains free parameters with three kinds of observation: (i) the log(N)-log(P) diagram of BATSE bursts; (ii) the…

Astrophysics · Physics 2008-11-26 F. Daigne , E. M. Rossi , R. Mochkovitch

We present an analysis of importance feature selection applied to photometric redshift estimation using the machine learning architecture Decision Trees with the ensemble learning routine Adaboost (hereafter RDF). We select a list of 85…

Instrumentation and Methods for Astrophysics · Physics 2015-06-23 Ben Hoyle , Markus Michael Rau , Roman Zitlau , Stella Seitz , Jochen Weller

Classifying Active Galactic Nuclei (AGN) is a challenge, especially for BL Lac Objects (BLLs), which are identified by their weak emission line spectra. To address the problem of classification, we use data from the 4th Fermi Catalog, Data…

High Energy Astrophysical Phenomena · Physics 2023-09-12 Nathaniel Cooper , Maria Giovanna Dainotti , Aditya Narendra , Ioannis Liodakis , Malgorzata Bogdan

Next-generation radio surveys are expected to detect tens of millions of active galactic nuclei (AGN) with a median redshift of z > 1. Beyond targeted surveys, the vast majority of these objects will not have spectroscopic redshifts, whilst…

Astrophysics of Galaxies · Physics 2020-11-03 Ross J. Turner , Guillaume Drouart , Nick Seymour , Stanislav S. Shabala

We explore the potential of an artificial neural network (ANN) based method intelligence to probe the propagation of cosmic $\gamma$-ray photons in the extragalactic Universe. The journey of $\gamma$-rays emitted from a distant source like…

High Energy Astrophysical Phenomena · Physics 2021-09-29 K K Singh , V K Dhar , P J Meintjes

Aims. We explore machine learning techniques to forecast star formation rate, stellar mass, and metallicity across galaxies with redshifts ranging from 0.01 to 0.3. Methods. Leveraging CatBoost and deep learning architectures, we utilize…

Astrophysics of Galaxies · Physics 2024-05-27 F. Z. Zeraatgari , F. Hafezianzadeh , Y. -X. Zhang , A. Mosallanezhad , J. -Y. Zhang

As the number of observed Gamma-Ray Bursts (GRBs) continues to grow, follow-up resources need to be used more efficiently in order to maximize science output from limited telescope time. As such, it is becoming increasingly important to…

Instrumentation and Methods for Astrophysics · Physics 2015-06-03 Adam N. Morgan , James Long , Joseph W. Richards , Tamara Broderick , Nathaniel R. Butler , Joshua S. Bloom

Theory suggests that about 10% of Swift-detected gamma-ray bursts (GRBs) will originate at redshifts greater than 5 yet a number of high redshift candidates may be left unconfirmed due to the lack of measured redshifts. Here we introduce…

We re-examine the technique of determining the redshifts of galaxies from the ratio of the submillimeter-to-radio continuum flux densities based on a recently published catalog of 850~$\mu$m sources. We derived the expected variation of…

Astrophysics · Physics 2015-06-24 T. N. Rengarajan , Tsutomu T. Takeuchi

The deepest all-sky survey available in the $\gamma$-ray band - the last release of the Fermi-LAT catalogue (4FGL-DR3) based on the data accumulated in 12 years, contains more than 6600 sources. The largest population among the sources is…

High Energy Astrophysical Phenomena · Physics 2022-12-28 N. Sahakyan , V. Vardanyan , M. Khachatryan

Gamma-ray Bursts (GRBs) are valuable probes of cosmic star formation reaching back into the epoch of reionization, and a large dataset with known redshifts ($z$) is an important ingredient for these studies. Usually, $z$ is measured using…

High Energy Astrophysical Phenomena · Physics 2026-05-13 Dhruv S. Bal , Aditya Narendra , Maria Giovanna Dainotti , Nikita S. Khatiya , Aleksander L. Lenart , Dieter H. Hartmann

We present a catalogue of photometric redshifts for galaxies from DESI Legacy Imaging Surveys, which includes $\sim0.18$ billion sources covering 14,000 ${\rm deg}^2$. The photometric redshifts, along with their uncertainties, are estimated…

Astrophysics of Galaxies · Physics 2025-02-25 Xingchen Zhou , Nan Li , Hu Zou , Yan Gong , Furen Deng , Xuelei Chen , Qian Yu , Zizhao He , Boyi Ding

In this paper, we calibrate the luminosity relation of gamma-ray bursts (GRBs) by Artificial Neural Networks (ANN) which is employed to analyze the Pantheon+ sample of type Ia supernovae (SNe Ia) in a manner independent of cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-25 Zhen Huang , Xin Luo , Bin Zhang , Jianchao Feng , Puxun Wu , Yu Liu , Nan Liang

The source-count distribution as a function of their flux, dN/dS, is one of the main quantities characterizing gamma-ray source populations. We employ statistical properties of the Fermi Large Area Telescope (LAT) photon counts map to…

High Energy Astrophysical Phenomena · Physics 2016-07-28 Hannes-S. Zechlin , Alessandro Cuoco , Fiorenza Donato , Nicolao Fornengo , Andrea Vittino

[Abbreviated] Upcoming large area sky surveys like EUCLID and eROSITA crucially depend on accurate photometric redshifts (photo-z). The identification of variable sources, such as AGNs, and the achievable redshift accuracy for varying…

Although not designed primarily as a polarimeter, the \textit{Fermi}-Large Area Telescope (LAT) has the potential to detect high degrees of linear polarization from some of the brightest gamma-ray sources. To achieve the needed accuracy in…

Instrumentation and Methods for Astrophysics · Physics 2019-08-14 Matteo Giomi , Rolf Bühler , Carmelo Sgrò , Francesco Longo , William Atwood

The first three months of sky-survey operation with the Fermi Gamma Ray Space Telescope (Fermi) Large Area Telescope (LAT) reveals 132 bright sources at |b|>10 deg with test statistic greater than 100 (corresponding to about 10 sigma). Two…

High Energy Astrophysical Phenomena · Physics 2009-09-30 A. A. Abdo

A new method to constrain the distance of blazars with unknown redshift using combined observations in the GeV and TeV regimes will be presented. The underlying assumption is that the Very High Energy (VHE) spectrum corrected for the…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-02 Elisa Prandini , Giacomo Bonnoli , Laura Maraschi , Mose' Mariotti , Fabrizio Tavecchio
‹ Prev 1 3 4 5 6 7 10 Next ›