Search Publications
Generating Stellar Spectra Using Neural Networks
Gebran, Marwan
A new generative technique is presented in this paper that uses Deep Learning to reconstruct stellar spectra based on a set of stellar parameters. Two different Neural Networks were trained allowing the generation of new spectra. First, an autoencoder is trained on a set of BAFGK synthetic data calculated using ATLAS9 model atmospheres and SYNSPEC…
Activity of main-belt comet 324P/La Sagra
Agarwal, J.; Kim, Y.; Mastropietro, M. +1 more
Aims. We study the activity evolution of the main-belt comet 324P/La Sagra over time and the properties of its emitted dust. Methods. We performed aperture photometry on images taken by a wide range of telescopes at optical and thermal infrared wavelengths between 2010 and 2021. We derived the combined scattering cross section of the nucleus and d…
Kinematic properties and ages of extended fast, neutral gas around η Carinae: tracing the pre-eruption bipolar wind
Smith, Nathan; Morse, Jon A.
We present proper-motion measurements and long-slit spectroscopy of the Mg II nebula around η Carinae obtained with the Wide Field Camera 3 and Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope. Detailed kinematics of the Mg II-emitting material constrain the geometry and history of mass-loss from η Car, and provide est…
Systematic Study of the Inner Structure of Molecular Tori in Nearby U/LIRGs Using Velocity Decomposition of CO Rovibrational Absorption Lines
Onishi, Shusuke; Nakagawa, Takao; Baba, Shunsuke +6 more
Determining the inner structure of the molecular torus around an active galactic nucleus is essential for understanding its formation mechanism. However, spatially resolving the torus is difficult because of its small size. To probe the clump conditions in the torus, we therefore perform the systematic velocity-decomposition analyses of the gaseou…
Criteria for Forecasting Proton Events by Real-Time Solar Observations
Struminsky, A. B.; Grigorieva, I. Yu.; Sadovskii, A. M.
The sequence for overcoming the threshold values of a number of physical characteristics for proton event forecasting in real time is discussed. Each characteristic adds a new physical meaning that refines the forecast. To take into account all the characteristics, the following continuous patrol observations are necessary: (1) the magnetic field …
The COS CGM Compendium. V. The Dichotomy of O VI Associated with Low- and High-metallicity Cool Gas at z < 1
Sameer; Fox, Andrew J.; Lehner, Nicolas +3 more
We analyze the O VI content and kinematics for 126 H I-selected absorbers at 0.14 ≲ z ≲ 0.73 for which the metallicities of their cool photoionized phase have been determined. We separate the absorbers into 100 strong Lyα forest systems (SLFSs with 15 ≲ log N(H I) < 16.2) and 26 partial Lyman Limit systems (pLLSs with 16.2 ≤ log N(H I) ≤ 17.2).…
Siril: An Advanced Tool for Astronomical Image Processing
Richard, Cyril; Hourdin, Vincent; Melis, Cécile +1 more
Siril is a powerful open-source software package designed for the preprocessing and post-processing of astronomical images. It is particularly well-suited for astrophotography enthusiasts and professional astronomers alike. Siril provides advanced tools for tasks such as image stacking, calibration, registration, and enhancement, enabling users to…
Surviving Tidal Tails Around the Milky Way Bulge Globular Cluster NGC 6355
Piatti, Andrés E.
We present results of the analysis of a set of images obtained in the field of the Milky Way bulge globular cluster NGC 6355 using the Dark Energy Camera, which is attached to the 4 m Blanco telescope of the Cerro-Tololo Interamerican Observatory. We dealt with a heavy differential absorption across the observed field, a crowded field star populat…
The impact of improved estimates of radio star astrometric models on the alignment of the Gaia bright reference frame to ICRF3
Lestrade, Jean-François; Xu, Ming H.; Anderson, James M. +12 more
Aims. We investigated the residual orientation offset and spin between the bright (G ≤ 13 mag) frame of the Gaia Early Data Release 3 (Gaia EDR3) and the third realization of the International Celestial Reference Frame (ICRF3). For this purpose, six rotation parameters (orientation offset and its time derivative, the spin), as well as corrections …
Bayesian characterization of the young open cluster NGC 6383 using HDBSCAN and Gaia DR3
Pulgar-Escobar, L. M.; Henríquez-Salgado, N. A.
This study focuses on determining the characteristics of the young open cluster NGC 6383. To achieve this, the HDBSCAN clustering algorithm is utilized to identify potential cluster members based on proper motions and parallaxes from Gaia Data Release 3. Various parameters of NGC 6383, such as tidal radius, core radius, distance through parallax a…