A5068456751- Astrophysical Phenomena and Observations
- Galaxies: Formation, Evolution, Phenomena
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Advancements in Semiconductor Devices and Circuit Design
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Electrical Fault Detection and Protection
- Astronomical Observations and Instrumentation
- Astrophysics and Star Formation Studies
- Advanced Optical Sensing Technologies
- Non-Destructive Testing Techniques
- Radio Astronomy Observations and Technology
- Particle Accelerators and Free-Electron Lasers
- Pulsars and Gravitational Waves Research
- Particle Detector Development and Performance
- Superconducting Materials and Applications
- Anomaly Detection Techniques and Applications
- Computational Physics and Python Applications
- Medical Imaging Techniques and Applications
- Mechanics and Biomechanics Studies
- Statistics Education and Methodologies
- MRI in cancer diagnosis
- X-ray Spectroscopy and Fluorescence Analysis
- Radiation Detection and Scintillator Technologies
University of Valparaíso
2018-2024
Millennium Institute of Astrophysics
2021-2024
Valparaiso University
2023
Institute for Space Astrophysics and Planetology
2017-2018
Instituto de Astrofísica de Andalucía
2011-2017
Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna
2017
Durango Institute of Technology
2016
Secretaria de Salud
2016
Consejo Superior de Investigaciones Científicas
2015
Universidad Nacional Autónoma de México
2011
The eighteenth data release of the Sloan Digital Sky Surveys (SDSS) is first one for SDSS-V, fifth generation survey. SDSS-V comprises three primary scientific programs, or "Mappers": Milky Way Mapper (MWM), Black Hole (BHM), and Local Volume (LVM). This contains extensive targeting information two multi-object spectroscopy programs (MWM BHM), including input catalogs selection functions their numerous objectives. We describe production databases calibration- scientifically-focused...
Abstract “Changing-look” active galactic nuclei (CL-AGNs) challenge our basic ideas about the physics of accretion flows and circumnuclear gas around supermassive black holes. Using first-year Sloan Digital Sky Survey V (SDSS-V) repeated spectroscopy nearly 29,000 previously known (AGNs), combined with dedicated follow-up spectroscopy, publicly available optical light curves, we have identified 116 CL-AGNs where (at least) one broad emission line has essentially (dis-)appeared, as well 88...
ABSTRACT Determining the frequency and duration of changing-look (CL) active galactic nuclei (AGNs) phenomena, where optical broad emission lines appear or disappear, is crucial to understand evolution accretion flow around supermassive black holes. We present a strategy select new CL candidates starting from spectroscopic type 2 AGN sample searching for current 1 photometric variability. use publicly available Zwicky Transient Facility alert stream Automatic Learning Rapid Classification...
One of the most important features in active galactic nuclei (AGN) is variability their emission. Variability has been discovered at X-ray, UV, and radio frequencies on time scales from hours to years. Among AGN family according theoretical studies, Low-Ionization Nuclear Emission Line Region (LINER) would be variable objects long scales. Our purpose investigate spectral X-ray LINERs understand nature these kinds objects, as well accretion mechanism. Chandra XMM-Newton public archives were...
Most of the optically classified low ionisation narrow emission-line regions (LINERs) nuclei host an active galactic (AGN). However, how they fit into unified model (UM) AGN is still open question. The aims this work are to study at mid-infrared (mid-IR) (1) Compton-thick nature LINERs; and (2) disappearance dusty torus in LINERs predicted from theoretical arguments. We have compiled all available spectral resolution mid-IR spectra IRS/Spitzer (40 LINERs). complemented sample with...
The classic classification scheme for Active Galactic Nuclei (AGNs) was recently challenged by the discovery of so-called changing-state (changing-look) AGNs (CSAGNs). physical mechanism behind this phenomenon is still a matter open debate and samples are too small serendipitous nature to provide robust answers. In order tackle problem, we need design methods that able detect AGN right in act changing-state. Here present an anomaly detection (AD) technique designed identify light curves with...
Abstract We report the discovery of a new “changing-look” active galactic nucleus (CLAGN) event, in quasar SDSS J162829.17+432948.5 at z = 0.2603, identified through repeat spectroscopy from fifth Sloan Digital Sky Survey (SDSS-V). Optical photometry taken during 2020–2021 shows dramatic dimming Δ g ≈ 1 mag, followed by rapid recovery on timescale several months, with ≲2 month period rebrightening captured SDSS-V and Las Cumbres Observatory spectroscopy. This is one fastest CLAGN transitions...
ABSTRACT We present second epoch optical spectra for 30 changing-look (CL) candidates found by searching Type-1 variability in a sample of active galactic nuclei (AGNs) spectroscopically classified as Type 2. use random-forest-based light-curve classifier and spectroscopic follow-up, confirming 50 per cent turning-on CLs. In order to improve this selection method better understand the nature not-confirmed CL candidates, we perform multiwavelength analysis including optical, mid-infrared...
ABSTRACT Quasars emission is highly variable, and this variability gives us clues to understand the accretion process onto supermassive black holes. We can expect properties correlate with main physical of accreting hole, i.e. its mass rate. It has been established that relative amplitude anticorrelates The dependence variance on hole remained elusive, contradicting results, including positive, negative, or no correlation, have reported. In work, we show key these contradictions lies in...
The eighteenth data release of the Sloan Digital Sky Surveys (SDSS) is first one for SDSS-V, fifth generation survey. SDSS-V comprises three primary scientific programs, or "Mappers": Milky Way Mapper (MWM), Black Hole (BHM), and Local Volume (LVM). This contains extensive targeting information two multi-object spectroscopy programs (MWM BHM), including input catalogs selection functions their numerous objectives. We describe production databases calibration- scientifically-focused...
Context. The optical variability of quasars is one the few windows through which we can explore behaviour accretion discs around supermassive black holes. Aims. We aim to establish dependence properties, such as characteristic timescales and amplitude, on basic quasar parameters hole mass rate, controlling for rest-frame wavelength emission. Methods. Using large catalogues quasars, selected g -band light curves 4770 objects from Zwicky Transient Facility archive. All fall into a narrow...
Abstract Thanks to the rapidly increasing time-domain facilities, we are entering a golden era of research on gamma-ray bursts (GRBs). In this Letter, report our observations GRB 240529A with Burst Optical Observer and Transient Exploring System, 1.5 m telescope at Observatorio de Sierra Nevada, 2.5 Wide Field Survey Telescope China, Large Binocular Telescope, Telescopio Nazionale Galileo. The prompt emission shows two comparable energetic episodes separated by quiescence time roughly 400 s....
Context. Variability is a general property of active galactic nuclei (AGN). The way in which these changes occur at X-rays not yet clearly understood. In the particular case low-ionization nuclear emission line region (LINER) nuclei, variations on timescales from months to years have been found for some objects, but main driver still debated.
Context. The giant radio galaxy PBC J2333.9-2343 shows different characteristics at wavebands that are difficult to explain within the actual generic schemes of unification active galactic nuclei (AGN). It is therefore a good candidate host for phases nuclear activity.
We present our analysis of the X-ray variability two ultraluminous sources (ULXs) based on multiple XMM–Newton observations. show that linear rms–flux relation is in eight observations NGC 5408 X-1 and also three 6946 X-1, but data from other ULXs are generally not sufficient to constrain any relation. The presence this was previously reported only X-1; results a persistent property extends at least one variable ULX. speculate ubiquitous ULX variability, as it for luminous accreting sources....
The Balmer emission originated in the broad line region (BLR) of active galactic nuclei (AGNs) could be either weak and difficult to detect, or even absent, for low luminosity AGNs, as LINERs. Our goals this paper are threefold. First, we want explore AGN-nature nearby type-1 Second, aim at deriving a reliable interpretation different components lines by studying their kinematics ionization mechanism. Third, intend probe neutral gas these We study 22 local (z<0.025) LINERs from Palomar...
Giant Radio Galaxies (GRG) are the largest single entities in Universe, having a projected linear size exceeding 0.7 Mpc, which implies that they also quite old objects. They not common, representing fraction of only about 6% samples bright radio galaxies. While census 300 these objects has been built past years, still no light shed on conditions necessary to allow such an exceptional growth, whether environmental nature or linked inner accretion properties. Recent studies found galaxies...
About 6% of Radio Galaxies (RG) can reach linear sizes larger than 0.7 Mpc, and are then classified as Giant (GRG). The conditions that make possible the formation such big structures is still not clear - either core accretion properties or environmental factors. Recent studies have shown GRG be up to four times more abundant in hard X-ray selected (i.e. from INTEGRAL/IBIS Swift/BAT at >20 keV) RG samples. Moreover, a high fraction young radio sources found their cores suggests recently...
Abstract Several authors have claimed that less luminous active galactic nuclei (AGNs) are not capable of sustaining a dusty torus structure. Thus, gradual resizing the is expected when AGN luminosity decreases. Our aim to examine mid-infrared observations local AGNs different luminosities for and disappearance torus. We applied decomposition method described by Hernán-Caballero et al. sample ∼100 Spitzer /IRS spectra low-luminosity powerful Seyferts in order decontaminate component from...
Variability across the electromagnetic spectrum is a property of AGN that can help constraining physical properties these galaxies. This third serie papers with aim studying X-ray variability different families AGN. The main purpose this work to investigate pattern in sample optically selected type 2 Seyfert We use 26 Seyferts Veron-Cetty and Veron catalogue data available from Chandra and/or XMM-Newton public archives at epochs, timescales ranging few hours years. All spectra same source...
X-ray variability is very common in active galactic nuclei (AGN), but these variations may not occur similarly different families of AGN. We aim to disentangle the structure low ionization nuclear emission line regions (LINERs) compared Seyfert 2s by study their spectral properties and variations. assembled parameters patterns, which were obtained from simultaneous fittings. Major differences are observed luminosities, Eddington ratios, higher 2s. Short-term detected, while long-term changes...
Context. Multi-phase outflows play a central role in galaxy evolution shaping the properties of galaxies. Understanding and their effects low luminosity active galactic nuclei (AGNs), such as ionisation nuclear emission line regions (LINERs), is essential. LINERs bridge gap between normal galaxies, being most numerous AGN population local Universe. Aims. Our goal to analyse kinematics mechanisms multi-phase gas NGC 1052, prototypical LINER, order detect map ionised neutral phases putative...