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We present the multi-wavelength and environmental properties of 37 variability-selected active galactic nuclei (AGNs), including 30 low luminosity AGNs (LLAGNs), using a high cadence time-domain survey (ASAS-SN) from a spectroscopic sample…

Astrophysics of Galaxies · Physics 2025-01-30 Heechan Yuk , Xinyu Dai , Marko Mićić

The Fermi-Large Area Telescope (LAT) First Source Catalog (1FGL) was released in February 2010 and the Fermi-LAT 2-Year Source Catalog (2FGL) appeared in April 2012, based on data from 24 months of operation. Since their releases, many…

Using artificial neural network (ANN) predictions of total infra-red luminosities (LIR), we compare the host galaxy star formation rates (SFRs) of ~21,000 optically selected active galactic nuclei (AGN), 466 low excitation radio galaxies…

Astrophysics of Galaxies · Physics 2016-03-09 Sara L. Ellison , Hossen Teimoorinia , David J. Rosario , J. Trevor Mendel

We have developed an efficient Active Galactic Nucleus (AGN) selection method using 18-band Spectral Energy Distribution (SED) fitting in mid-infrared (mid-IR). AGNs are often obscured by gas and dust, and those obscured AGNs tend to be…

Astrophysics of Galaxies · Physics 2017-08-29 Ting-Chi Huang , Tomotsugu Goto , Tetsuya Hashimoto , Nagisa Oi , Hideo Matsuhara

We present QSFit, a new software package to automatically perform the analysis of Active Galactic Nuclei (AGN) optical spectra. The software provides luminosity estimates for the AGN continuum, the Balmer continuum, both optical and UV iron…

High Energy Astrophysical Phenomena · Physics 2017-09-12 G. Calderone , L. Nicastro , G. Ghisellini , M. Dotti , T. Sbarrato , F. Shankar , M. Colpi

We present a large sample of infrared-luminous candidate active galactic nuclei (AGNs) that lack X-ray detections in Chandra, XMM-Newton, and NuSTAR fields. We selected all optically detected SDSS sources with redshift measurements,…

Selection of active galactic nuclei (AGN) in the infrared allows the discovery of AGN whose optical emission is extinguished by dust. In this paper, we use the Spitzer Space Telescope First Look Survey (FLS) to assess what fraction of AGN…

Since a large fraction of active galactic nuclei (AGN) is missed in common UV-excess surveys and is even hard to find in radio, near-IR and X-ray surveys, we have used a new AGN selection technique which is expected to be not affected by…

Aims. We use a sample of 83 core-dominated active galactic nuclei (AGN) selected from the MOJAVE (Monitoring of Jets in AGN with VLBA Experiments) radio-flux-limited sample and detected with the Fermi Large Area Telescope (LAT) to study the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 T. G. Arshakian , J. León-Tavares , M. Boettcher , J. Torrealba , V. H. Chavushyan , M. L. Lister , E. Ros , J. A. Zensus

Due to the over-fitting problem caused by imbalance samples, there is still room to improve the performance of data-driven automatic modulation classification (AMC) in noisy scenarios. By fully considering the signal characteristics, an AMC…

Signal Processing · Electrical Eng. & Systems 2022-03-08 Hao Shi , Qi Peng , Yiqi Zhuang

In recent years, applying deep learning (DL) to assess structural damages has gained growing popularity in vision-based structural health monitoring (SHM). However, both data deficiency and class-imbalance hinder the wide adoption of DL in…

Machine Learning · Computer Science 2022-11-30 Yuqing Gao , Pengyuan Zhai , Khalid M. Mosalam

In order to determine the incidence of black hole accretion-driven nuclear activity in nearby galaxies, as manifested by their radio emission, we have carried out a high-resolution Multi-Element Radio-Linked Interferometer Network (MERLIN)…

Astrophysics · Physics 2009-11-11 M. E. Filho , P. D. Barthel , L. C. Ho

The Fermi-LAT satellite has recently discovered a small group of radio galaxies and steep spectrum radio sources: the misaligned AGNs (MAGNs) sample. We present the X-ray analysis of all the sources of this sample (7 FRIs and 3 FRIIs) with…

High Energy Astrophysical Phenomena · Physics 2012-05-09 Eleonora Torresi

Active galactic nuclei (AGNs) in the high-redshift Universe are thought to reside in overdense environments. However, recent works provide controversial results partly due to the use of different techniques and possible suppression of…

Astrophysics of Galaxies · Physics 2017-06-21 Satoshi Kikuta , Masatoshi Imanishi , Yoshiki Matsuoka , Yuichi Matsuda , Kazuhiro Shimasaku , Fumiaki Nakata

In order to answer some of the major open questions in the fields of supermassive black hole (SMBH) and galaxy evolution, a complete census of SMBH growth, i.e., active galactic nuclei (AGN), is required. Thanks to deep all-sky surveys,…

We cross correlate the Fermi 11 months survey catalogue (1FGL) with the 20 GHz Australia Telescope Compact Array radio survey catalogue (AT20G) composed by 5890 sources at declination <0 deg. Among the 738 Fermi sources distributed in the…

High Energy Astrophysical Phenomena · Physics 2015-05-18 G. Ghirlanda , G. Ghisellini , F. Tavecchio , L. Foschini

Multiple imputation (MI) has been widely applied to missing value problems in biomedical, social and econometric research, in order to avoid improper inference in the downstream data analysis. In the presence of high-dimensional data,…

Methodology · Statistics 2023-05-04 Zhiqi Bu , Zongyu Dai , Yiliang Zhang , Qi Long

Mid-infrared observations are powerful in identifying heavily obscured Active Galactic Nuclei (AGN) which have weak emission in other wavelengths. Data from the Mid-Infrared Instrument (MIRI) onboard JWST provides an excellent opportunity…

In order to understand the interaction between the central black hole and the whole galaxy or their co-evolution history along with cosmic time, a complete census of active galactic nuclei (AGN) is crucial. However, AGNs are often missed in…

We present the 4MOST-HR resolution Non-Local Thermal Equilibrium (NLTE) Payne artificial neural network (ANN), trained on $404\,793$ new FGK spectra with 16 elements computed in NLTE. This network will be part of the Stellar Abundances and…

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