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

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Studies of high-redshift gamma-ray bursts (GRBs) provide important information about the early Universe such as the rates of stellar collapsars and mergers, the metallicity content, constraints on the re-ionization period, and probes of the…

High Energy Astrophysical Phenomena · Physics 2016-03-23 T. N. Ukwatta , P. R. Wozniak , N. Gehrels

We present a composite machine learning framework to estimate posterior probability distributions of bulge-to-total light ratio, half-light radius, and flux for Active Galactic Nucleus (AGN) host galaxies within $z<1.4$ and $m<23$ in the…

Redshift estimation and the classification of gamma-ray AGNs represent crucial challenges in the field of gamma-ray astronomy. Recent efforts have been made to tackle these problems using traditional machine learning methods. However, the…

High Energy Astrophysical Phenomena · Physics 2024-08-27 Sarvesh Gharat , Abhimanyu Borthakur , Gopal Bhatta

The second Fermi-LAT source catalog (2FGL) is the deepest all-sky survey available in the gamma-ray band. It contains 1873 sources, of which 576 remain unassociated. Machine-learning algorithms can be trained on the gamma-ray properties of…

High Energy Astrophysical Phenomena · Physics 2014-01-29 M. Doert , M. Errando

In this paper, we discuss an artificial intelligence based approach to constrain the redshift of blazars using combined $\gamma$--ray observations from the \emph{Fermi} Large Area Telescope (LAT) and ground based atmospheric Cherenkov…

High Energy Astrophysical Phenomena · Physics 2019-11-26 K K Singh , V K Dhar , P J Meintjes

Correlating BASS DR3 catalogue with ALLWISE database, the data from optical and infrared information are obtained. The quasars from SDSS are taken as training and test samples while those from LAMOST are considered as external test sample.…

Instrumentation and Methods for Astrophysics · Physics 2021-11-17 Changhua Li , Yanxia Zhang , Chenzhou Cui , Dongwei Fan , Yongheng Zhao , Xue-Bing Wu , Jing-Yi Zhang , Jun Han , Yunfei Xu , Yihan Tao , Shanshan Li , Boliang He

The lack of bright host galaxies in several recently examined gamma-ray burst (GRB) error boxes suggests that the redshifts of cosmological GRBs may be significantly higher than previously believed. On the other hand, the non-detection of…

Astrophysics · Physics 2009-10-30 Daniel E. Holz , M. Coleman Miller , Jean M. Quashnock

Active Galactic Nuclei (AGN) are relevant sources of radiation that might have helped reionising the Universe during its early epochs. The super-massive black holes (SMBHs) they host helped accreting material and emitting large amounts of…

Astrophysics of Galaxies · Physics 2021-11-02 Rodrigo Carvajal , Israel Matute , José Afonso , Stergios Amarantidis , Davi Barbosa , Pedro Cunha , Andrew Humphrey

Classification of sources is one of the most important tasks in astronomy. Sources detected in one wavelength band, for example using gamma rays, may have several possible associations in other wavebands, or there may be no plausible…

High Energy Astrophysical Phenomena · Physics 2022-04-19 Aakash Bhat , Dmitry Malyshev

Observations of distant gamma-ray sources are hindered by the presence of the extragalactic background light (EBL). In order to understand the physical processes that result in the observed spectrum of sources, it is imperative that a good…

High Energy Astrophysical Phenomena · Physics 2017-06-01 Thomas Armstrong , Anthony M. Brown , Paula M. Chadwick

Large fraction of studies of active galactic nuclei objects is based on performing follow-up observations using high-sensitivity instruments of high flux states observed by monitoring instruments (the so-called Target of Opportunity, ToO).…

Instrumentation and Methods for Astrophysics · Physics 2021-10-27 Tomasz Fidor , Julian Sitarek

Long duration Gamma-Ray Bursts (LGRBs) may serve as standard candles to constrain cosmological parameters by probing the Hubble diagram well beyond the range of redshift currently accessible using type-Ia supernovae. The standardization of…

High Energy Astrophysical Phenomena · Physics 2019-12-30 F. Fana Dirirsa , S. Razzaque , F. Piron , M. Arimoto , M. Axelsson , D. Kocevski , F. Longo , M. Ohno , S. Zhu

We present AGNBoost, a machine learning framework utilizing XGBoostLSS to identify AGN and estimate redshifts from JWST NIRCam and MIRI photometry. AGNBoost constructs 66 input features from 7 NIRCam and 4 MIRI bands to predict the fraction…

The classifications of Fermi-LAT unassociated sources are studied using multiple machine learning (ML) methods. The update data from 4FGL-DR3 are divided into high Galactic latitude (HGL, Galactic latitude $|b|>10^\circ$) and low Galactic…

High Energy Astrophysical Phenomena · Physics 2023-11-08 K. R. Zhu , J. M. Chen , Y. G. Zheng , L. Zhang

While the available set of Gamma-ray Burst (GRB) data with known redshift is currently limited, a much larger set of GRB data without redshift is available from different instruments. This data includes well-measured prompt gamma-ray flux…

High Energy Astrophysical Phenomena · Physics 2024-03-25 Tamador Aldowma , Soebur Razzaque

Gamma rays from extragalactic sources are attenuated by pair-production interactions with diffuse photons of the extragalactic background light (EBL). Gamma-ray bursts (GRBs) are a source of high-redshift photons above 10 GeV, and could be…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Rudy C. Gilmore , Francisco Prada , Joel R. Primack

We reconstruct the extra-galactic gamma-ray source-count distribution, or $dN/dS$, of resolved and unresolved sources by adopting machine learning techniques. Specifically, we train a convolutional neural network on synthetic 2-dimensional…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-16 Aurelio Amerio , Alessandro Cuoco , Nicolao Fornengo

Gamma-ray bursts (GRBs) can be probes of the early universe, but currently, only 26% of GRBs observed by the Neil Gehrels Swift Observatory GRBs have known redshifts ($z$) due to observational limitations. To address this, we estimated the…

We considered the fourth catalog of gamma-ray point sources produced by the Fermi Large Area Telescope (LAT) and selected only jetted active galactic nuclei (AGN) or sources with no specific classification, but with a low-frequency…

We have obtained high dynamic range, good natural seeing i' images of BL Lacertae objects (BL Lacs) to search for the AGN host and thus constrain the source redshift. These objects are drawn from a sample of bright flat-spectrum radio…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Aaron M. Meisner , Roger W. Romani