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We present our study on the reconstruction of photoelectron tracks in gas pixel detectors used for astrophysical X-ray polarimetry. Our work aims to maximize the performance of convolutional neural networks (CNNs) to predict the impact…

Reliable, versatile galaxy activity diagnostics are essential for understanding galaxy evolution. Traditional methods frequently necessitate extensive preprocessing, such as starlight subtraction and emission line deblending (e.g.,…

Astrophysics of Galaxies · Physics 2026-02-25 C. Daoutis , A. Zezas , E. Kyritsis , K. Kouroumpatzakis , P. Bonfini

We propose R3GS, a robust reconstruction and relocalization framework tailored for unconstrained datasets. Our method uses a hybrid representation during training. Each anchor combines a global feature from a convolutional neural network…

Computer Vision and Pattern Recognition · Computer Science 2025-05-22 Xu yan , Zhaohui Wang , Rong Wei , Jingbo Yu , Dong Li , Xiangde Liu

Unification Models of Active Galactic Nuclei postulate that all the observed differences between Type 1 and Type 2 objects are due to orientation effects with respect to the line-of-sight to the observer. The key ingredient of these models…

Astrophysics of Galaxies · Physics 2015-06-03 Stefano Bianchi , Roberto Maiolino , Guido Risaliti

In the recent years, there has been a significant improvement in the quality of samples produced by (deep) generative models such as variational auto-encoders and generative adversarial networks. However, the representation capabilities of…

Image and Video Processing · Electrical Eng. & Systems 2026-03-31 Shady Abu Hussein , Tom Tirer , Raja Giryes

Image inpainting aims at restoring missing region of corrupted images, which has many applications such as image restoration and object removal. However, current GAN-based inpainting models fail to explicitly consider the semantic…

Computer Vision and Pattern Recognition · Computer Science 2019-12-17 Ang Li , Jianzhong Qi , Rui Zhang , Ramamohanarao Kotagiri

A handful of well-studied Weak-Line Radio Galaxies (WLRGs) have been traditionally classified as Low Ionization Nuclear Emission-line Regions (LINERs), suggesting that these two groups of AGNs might be related. In this paper, we present new…

Astrophysics · Physics 2009-11-07 Karen T. Lewis , Michael Eracleous , Rita M. Sambruna

This is the first paper in a series dealing with optical Nitrogen spectroscopy of O-type stars, aiming at the analysis of Nitrogen abundances. We implemented a new Nitrogen model atom into the NLTE atmosphere/spectrum synthesis code…

Solar and Stellar Astrophysics · Physics 2015-05-30 Jorge G. Rivero Gonzalez , Joachim Puls , Francisco Najarro

Reionisation-era galaxies often display intense nebular emission lines, both in rest-frame optical ([OIII]+H$\beta$) and ultraviolet (UV; CIII], CIV). How such strong nebular emission is powered remains unclear, with both active galactic…

Astrophysics of Galaxies · Physics 2021-11-24 Mengtao Tang , Daniel P. Stark , Richard S. Ellis , Stéphane Charlot , Anna Feltre , Alice E. Shapley , Ryan Endsley

Weak gravitational lensing on a cosmological scales can provide strong constraints both on the nature of dark matter and the dark energy equation of state. Most current weak lensing studies are restricted to (two-dimensional) projections,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Dipak Munshi , Alan Heavens , Peter Coles

The fractionation of nitrogen (N) in star-forming regions is a poorly understood process. To put more stringent observational constraints on the N-fractionation, we have observed with the IRAM-30m telescope a large sample of 66 cores in…

Solar and Stellar Astrophysics · Physics 2018-05-02 L. Colzi , F. Fontani , V. M. Rivilla , A. Sánchez-Monge , L. Testi , M. T. Beltrán , P. Caselli

Label-free tomographic microscopy offers a compelling means to visualize three-dimensional (3D) refractive index (RI) distributions from two-dimensional (2D) intensity measurements. However, limited forward-model accuracy and the ill-posed…

Optics · Physics 2025-02-27 Delong Yang , Shaohui Zhang , Jiasong Sun , Chao Zuo , Qun Hao

We describe a pseudo-3D photoionization code, NEBU_3D and its associated visualization tool, VIS_NEB3D, which are able to easily and rapidly treat a wide variety of nebular geometries, by combining models obtained with a 1D photoionization…

Astrophysics · Physics 2007-05-23 C. Morisset , G. Stasinska , M. Pena

Photometric surveys have provided incredible amounts of astronomical information in the form of images. However, astronomical images often contain artifacts that can critically hinder scientific analysis by misrepresenting intensities or…

Instrumentation and Methods for Astrophysics · Physics 2020-06-03 Suchetha Cooray , Tsutomu T. Takeuchi , Moe Yoda , Kazuo Sorai

Using the 3XMM catalogue of serendipitous X-ray sources, and the SDSS-DR9 spectroscopic catalogue, we have obtained a new sample of X-ray selected narrow emission line galaxies. The standard optical diagnostic diagram and selection by hard…

High Energy Astrophysical Phenomena · Physics 2014-09-05 Estelle Pons , Mike G. Watson

A review of the spectroscopic tools needed to characterize AGNs is presented. This review focusses on ultraviolet, optical and infrared emission-line diagnostics specifically designed to help differentiate AGNs from starburst-dominated…

Astrophysics · Physics 2007-05-23 Sylvain Veilleux

The fraction of ionizing photons escaping from high-redshift star-forming galaxies remains a key obstacle in evaluating whether galaxies were the primary agents of cosmic reionization. We previously proposed using the covering fraction of…

Astrophysics of Galaxies · Physics 2016-11-15 Nicha Leethochawalit , Tucker A. Jones , Richard S. Ellis , Daniel P. Stark , Adi Zitrin

Once thought to be devoid of warm and cold interstellar matter, elliptical galaxies are now commonly observed to host extended regions of neutral and ionized gas. Outside of the innermost nuclear regions of these galaxies, the favoured…

Solar and Stellar Astrophysics · Physics 2014-03-05 T. E. Woods , M. Gilfanov

Star-forming dwarf galaxies in the local Universe, especially extremely metal-poor ones, can be considered analogous to early galaxies of the Epoch of Reionization (z >= 6). Currently available telescopes cannot adequately detect and…

Modelling reionization often requires significant assumptions about the properties of ionizing sources. Here, we infer the total output of hydrogen-ionizing photons (the ionizing emissivity, $\dot{N}_\textrm{ion}$) at $z=4-14$ from current…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-12 Charlotte A. Mason , Rohan P. Naidu , Sandro Tacchella , Joel Leja