A5017557147- Galaxies: Formation, Evolution, Phenomena
- Astrophysical Phenomena and Observations
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Radio Astronomy Observations and Technology
- Cosmology and Gravitation Theories
- Solar and Space Plasma Dynamics
- Dark Matter and Cosmic Phenomena
- Historical Studies in Science
- Pulsars and Gravitational Waves Research
- Adaptive optics and wavefront sensing
- Geophysics and Gravity Measurements
- Advanced Image Processing Techniques
- Relativity and Gravitational Theory
- Statistical and numerical algorithms
- Atomic and Molecular Physics
- Ionosphere and magnetosphere dynamics
- Particle accelerators and beam dynamics
- Advanced Vision and Imaging
- Plant Water Relations and Carbon Dynamics
- Black Holes and Theoretical Physics
Universidad Nacional Autónoma de México
2015-2025
University of Padua
2018
Universidad Autónoma Monterrey
2015
(Abridged) We have conducted a detailed investigation of the broad-band spectral properties \gamma-ray selected blazars Fermi LAT Bright AGN Sample (LBAS). By combining our accurately estimated gamma-ray spectra with Swift, radio, infra-red, optical and other hard X-ray/gamma-ray data, collected within three months LBAS data taking period, we were able to assemble high-quality quasi-simultaneous Spectral Energy Distributions (SED) for 48 blazars.The SED these sources is similar that...
[Abridged] We have been exploring a spectroscopic unification for all known types of broad line emitting AGN. The 4D Eigenvector 1 (4DE1) parameter space shows promise as capable organizing quasar diversity on sequence primarily governed by Eddington ratio. This paper considers the role CIV 1549 measures with special emphasis shift principal 4DE1 diagnostic. use HST archival spectra 130 sources S/N high enough to permit reliable component (BC) measures. find BC profile blueshift that is...
Abstract We present the results of prompt optical follow-up electromagnetic counterpart gravitational-wave event GW170817 by Transient Optical Robotic Observatory South Collaboration. detected highly significant dimming in light curves ( mag, mag) over course only 80 minutes observations obtained ∼35 hr after trigger with T80-South telescope. A second epoch observations, ∼59 EABA 1.5 m telescope, confirms fast fading nature transient. The observed colors suggest that this was a “blue...
The last 25 years saw a major step forward in the analysis of optical and UV spectroscopic data large quasar samples. Multivariate statistical approaches have led to definition systematic trends observational properties that are basis physical dynamical modeling structure. We discuss empirical correlates so-called “main sequence” associated with Eigenvector 1, its governing parameters several implications on our view structure, as well some luminosity effects virialized component line...
We explore the properties of Hβ emission line profile in a large, homogeneous and bright sample N∼ 470 low redshift quasars extracted from Sloan Digital Sky Survey (DR5).We approach investigation two complementary directions: composite/median spectra set diagnostic measures (asymmetry index, centroid shift kurtosis) individual quasars.The project is developed presented framework so called 4D Eigenvector 1 Parameter Space, with focus on its optical dimensions, FWHM(Hβ) relative strength FeII...
We compare broad emission line profiles and estimate ratios for all major lines between Lyα Hβ in a sample of six quasars.The sources were chosen with two criteria mind: the existence high quality optical UV spectra as well possibility to spectroscopic diversity 4D Eigenvector 1 context (4DE1).In latter sense each source occupies region (bin) FWHM(Hβ) vs. Fe ii opt strength plane that is significantly different from others.High S/N are used templates modeling other (Lyα, Civλ1549, Heiiλ1640,...
We report on 18 months of multiwavelength observations the blazar 3C 454.3 (Crazy Diamond) carried out in July 2007-January 2009. show results AGILE campaigns which took place May-June 2008, July-August and October 2008-January During May 2009 period, source average flux was highly variable, from an gamma-ray F(E>100MeV) > 200E-8 ph/cm2/s to F(E>100MeV)~80E-8 The spectrum between 100 MeV 1 GeV can be fit by a simple power law (Gamma_GRID ~ 2.0 2.2). Only 3-sigma upper limits derived 20-60...
Broad emission lines in quasars enable us to "resolve" structure and kinematics of the broad-line emitting region (BLR) thought involve an accretion disk feeding a supermassive black hole. Interpretation broad line measures within 4DE1 formalism simplifies apparent confusion among such data by contrasting unifying properties so-called high low accreting Population A B sources. Hβ serves as estimator hole mass, Eddington ratio source rest frame; latter being valuable input for Civλ1549...
The 4D (four-dimensional) eigenvector 1 (E1) sequence has proven to be a highly effective tool for organizing observational and physical properties of type-1 active galactic nuclei (AGNs). In this paper, we present multiple measurements metallicity the broad line region gas, from new previously-published data. We demonstrate consistent trend along optical plane E1 (also known as quasar main sequence), defined by width Balmer hydrogen Hβ profile parameter measuring prominence singly-ionized...
<i>Context. <i/>Since 2001, the radio quasar 3C 454.3 has undergone a period of high optical activity, culminating in brightest state ever observed, during 2004-2005 outburst. The Whole Earth Blazar Telescope (WEBT) consortium carried out several multifrequency campaigns to follow source behaviour.<i>Aims. <i/>The GLAST-AGILE Support Program (GASP) was born from WEBT provide long-term continuous optical-to-radio monitoring sample <i>γ<i/>-loud blazars, operation AGILE and GLAST (now known as...
The most highly accreting quasars (xA) are of special interest in studies the physics AGNs and host galaxy evolution. Quasars at high rates (L/LEdd $\sim$ 1) hold promise for use as 'standard candles': distance indicators detectable very redshift. However, their observational properties largely unknown. A large sample xA can clarify main radiating near L/LEdd 1 Hb spectral range redshift $\lt$ 0.8. We selection criteria derived from 4DE1 to identify analyze spectra a 334 candidate sources...
This review provides an observational perspective on the fundamental properties of super-Eddington accretion onto supermassive black holes in quasars. It begins by outlining selection criteria, particularly focusing optical and UV broad-line intensity ratios, used to identify a population unobscured candidates. Several defining features place these candidates at extreme end Population A main sequence quasars: among them are highest observed singly-ionized iron emission, outflow velocities...
<i>Context. <i/>BL Lacertae is the prototype of blazar subclass named after it. Yet, it has occasionally shown a peculiar behaviour that questioned simple interpretation its broad-band emission in terms synchrotron plus self-Compton (SSC) radiation.<i>Aims. <i/>In 2007–2008 observing season we carried out new multiwavelength campaign Whole Earth Blazar Telescope (WEBT) on BL Lacertae, involving three pointings by XMM-Newton satellite July and December 2007, January 2008, to study properties,...
We present the results of a long-term (1999--2010) spectral optical monitoring campaign active galactic nucleus (AGN) Ark 564, which shows strong Fe II line emission in optical. This AGN is narrow Seyfert 1 (NLS1) galaxies, group AGNs with specific characteristics. analyze light curves permitted Ha, Hb, fluxes, and continuum flux order to search for time lag between them. Additionally, estimate contribution iron lines from different multiplets, we fit Hb sum Gaussian components. found that...
We describe a method for determination of physical conditions in the broad line regions significant subsample Seyfert-1 nuclei and quasars. Several diagnostic ratios based on intermediate (AlIII 1860, SiIII 1892) high (CIV 1549, SiIV 1397) ionization lines UV spectra quasars are used to constrain density, metallicity emitting gas. apply two extreme Population A - prototypical NLSy1 I Zw 1 high-z\ NLSy1-like object, SDSS J120144.36+011611.6. find well-defined conditions: low (ionization...
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...
Abstract This is the second in a series of papers devoted to exploring set six dusty models active galactic nuclei (AGN) with available spectral energy distributions. These are smooth torus by Fritz et al., clumpy Nenkova Hönig & Kishimoto, two-phase Siebenmorgen Stalevski and wind model Kishimoto. The first paper explores discrimination among parameter restriction using synthetic spectra. Here we perform fitting sample 110 AGN drawn from Swift /BAT survey Spitzer /IRS spectroscopic...
In the last decades, several multiwavelength studies have been dedicated to exploring properties of obscuring material in active galactic nuclei (AGN). Various models developed describe structure and distribution this constrain its physical geometrical parameters through spectral fitting techniques. However, questions, including how torus mid-infrared (mid-IR) X-ray emission are related remain unanswered. work, we study whether dust continuum at mid-IR gas reflection X-rays same a sample...
Aims. Results of long-term spectral monitoring the active galactic nucleus NGC 4151 are presented (11 years, from 1996 to 2006).
The connection between multifrequency quasar observational and physical parameters related to accretion processes is still open debate. In the last 20 year, Eigenvector 1-based approaches developed since early papers by Boroson Green (1992) Sulentic et al. (2000b) have been proven be a remarkably powerful tool investigate this issue, led definition of "main sequence". paper we perform cladistic analysis on two samples 215 85 low-z quasars (z 0.7) which were studied in several previous works...
[Abridged] Context: The advent of 8-10m class telescopes makes possible for the first time detailed comparison quasars with similar luminosity and very different redshifts. Aims: A search z-dependent gradients in line emission diagnostics derived physical properties by comparing, a narrow bolometric range (log L ~ 46.1 +/- 0.4 [\ergss]), some most luminous local (z < 0.6) lowest sources yet found at redshift z = 2.1 2.5. Method: Spectra 22 high were obtained 10.4m Gran Telescopio Canarias...
We present an unprecedented spectroscopic survey of the CaII triplet + OI for a sample 14 luminous ($-$26 $\gtrsim$ M$_V$ $-$29), intermediate redshift (0.85 $\lesssim$ $z$ 1.65) quasars. The ISAAC spectrometer at ESO VLT allowed us to cover NIR spectral region redshifted into H and K windows. describe in detail our data analysis which enabled detect emission all sources (with possible exception HE0048-2804) retrieve accurate line widths fluxes $\lambda$8446. new measurements show trends...
The inter-line comparison between high- and low-ionization emission lines has yielded a wealth of information on the quasar broad line region (BLR) structure dynamics, including perhaps earliest unambiguous evidence in favor disk + wind radio-quiet quasars. We carried out an analysis CIV 1549 Hbeta profiles 28 Hamburg-ESO high luminosity quasars 48 low-z, low sources order to test whether high-ionization width could be correlated with used as virial broadening estimator. analyze...