A. F. Rojas
A5069002409- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Astrophysics and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Pulsars and Gravitational Waves Research
- Astrophysics and Star Formation Studies
- Adaptive optics and wavefront sensing
- Atomic and Subatomic Physics Research
- Advanced Semiconductor Detectors and Materials
- Magnetism in coordination complexes
- Earthquake Detection and Analysis
- Organometallic Complex Synthesis and Catalysis
- Metal complexes synthesis and properties
- Photocathodes and Microchannel Plates
- Superconducting Materials and Applications
- Scientific Measurement and Uncertainty Evaluation
- Statistics Education and Methodologies
- Spectroscopy and Laser Applications
- Advanced X-ray Imaging Techniques
- Calibration and Measurement Techniques
- History and Developments in Astronomy
- Atmospheric Ozone and Climate
University of Antofagasta
2020-2023
Diego Portales University
2022-2023
Universidad Andrés Bello
2017-2019
European Southern Observatory
2019
Pontificia Universidad Católica de Chile
1985-2013
Context. The ESO public survey VISTA variables in the Vía Láctea (VVV) started 2010. VVV targets 562 sq. deg Galactic bulge and an adjacent plane region is expected to run for about five years.
Abstract We present the active galactic nucleus (AGN) catalog and optical spectroscopy for second data release of Swift BAT AGN Spectroscopic Survey (BASS DR2). With this DR2 we provide 1449 spectra, which 1182 are released first time, 858 hard-X-ray-selected AGNs in 70-month sample. The majority spectra (801/1449, 55%) newly obtained from Very Large Telescope (VLT)/X-shooter or Palomar/Doublespec. Many have both higher resolution ( R > 2500, N ∼ 450) and/or very wide wavelength coverage...
Abstract We present measurements of broad emission lines and virial estimates supermassive black hole masses ( M BH ) for a large sample ultrahard X-ray-selected active galactic nuclei (AGNs) as part the second data release BAT AGN Spectroscopic Survey (BASS/DR2). Our catalog includes total 689 AGNs, determined from H α , β Mg ii λ 2798, and/or C iv 1549 lines. The core 512 AGNs drawn 70 month Swift/BAT all-sky catalog. also provide 177 additional that are deeper survey data. study links...
Abstract We present new central stellar velocity dispersions for 484 Sy 1.9 and 2 from the second data release of Swift/BAT AGN Spectroscopic Survey (BASS DR2). This constitutes largest study dispersion measurements in X-ray-selected obscured active galactic nuclei (AGN) with 956 independent Ca ii H K λ 3969, 3934 Mg I 5175 region (3880–5550 Å) calcium triplet (8350–8730 642 spectra mainly VLT/X-Shooter or Palomar/DoubleSpec. Our sample spans 40–360 km s 1 , corresponding to 4–5 orders...
Abstract To understand the origin of nuclear (≲100 pc) millimeter-wave (mm-wave) continuum emission in active galactic nuclei (AGNs), we systematically analyzed subarcsecond resolution Band-6 (211–275 GHz) Atacama Large Millimeter/submillimeter Array data 98 nearby AGNs ( z < 0.05) from 70 month Swift/BAT catalog. The sample, almost unbiased for obscured systems, provides largest number to date with high mm-wave spatial sampling (∼1–200 pc), and spans broad ranges 14–150 keV luminosity {...
Abstract We present the second catalog and data release of optical spectral line measurements active galactic nucleus (AGN) demographics BAT AGN Spectroscopic Survey, which focuses on Swift-BAT hard X-ray detected AGNs. use spectra from dedicated campaigns publicly available archives to investigate properties most AGNs listed in 70 month all-sky catalog; specifically, 743 746 unbeamed unlensed (99.6%). find a good correspondence between emission widths hydrogen column density distributions...
ABSTRACT Ionized gas kinematics provide crucial evidence of the impact that active galactic nuclei (AGNs) have in regulating star formation their host galaxies. Although presence outflows AGN galaxies has been firmly established, calculation outflow properties such as mass rates and kinetic energy remains challenging. We present [O iii]λ5007 ionized 22 z&lt;0.1 X-ray AGN, derived from BAT Spectroscopic Survey using MUSE/VLT. With an average spatial resolution 1 arcsec (0.1–1.2 kpc),...
Abstract Virial black hole (BH) mass ( M BH ) determination directly involves knowing the broad-line region (BLR) clouds’ velocity distribution, their distance from central supermassive R BLR ), and virial factor f ). Understanding whether biases arise in estimation with increasing obscuration is possible only by studying a large N > 100) statistical sample of obscuration-unbiased (hard) X-ray-selected active galactic nuclei (AGNs) rest-frame near-infrared (0.8–2.5 μ m) since it...
ABSTRACT Changing-look (CL) AGN are unique probes of accretion onto supermassive black holes (SMBHs), especially when simultaneous observations in complementary wavebands allow investigations into the properties their flows. We present results a search for CL behaviour 412 Swift-BAT detected with multiple epochs optical spectroscopy from BAT Spectroscopic Survey (BASS). 125 these also have 14–195 keV ultra-hard X-ray light curves which contemporaneous spectroscopy. Eight events presented...
Within the framework of our program (running since 2004) identification hard X-ray INTEGRAL sources through optical spectroscopy, we present results concerning nature 33 high-energy objects. The data were acquired with use six telescopes different sizes and from one on-line archive. indicate that majority these objects (23 out 33) are active galactic nuclei (AGNs), whereas 10 in local Universe eight which Galaxy two Small Magellanic Cloud (SMC). Among identified AGNs, 13 Type 1 (i.e., broad...
We present a detailed study of ionized outflows in large sample ~650 hard X-ray detected AGN. Using optical spectroscopy from the BAT AGN Spectroscopic Survey (BASS) we are able to reveal faint wings [OIII] emission lines associated with covering, for first time, an unexplored range low bolometric luminosity at redshift (z~0.05). test if and how incidence velocity outflow is related physical parameters: black hole mass, gas column density, Eddington Ratio, [OIII], X-ray, luminosities. find...
Abstract We present a catalog of the millimeter-wave (mm-wave) continuum properties 98 nearby ( z < 0.05) active galactic nuclei (AGNs) selected from 70 month Swift/BAT hard-X-ray that have precisely determined X-ray spectral and subarcsecond-resolution Atacama Large Millimeter/submillimeter Array Band 6 (211–275 GHz) observations as 2021 April. Due to (>10 keV) selection, sample is nearly unbiased for obscured systems at least up Compton-thick-level obscuration, provides largest...
Through an optical campaign performed at four telescopes located in the northern and southern hemispheres, we have obtained spectroscopy for 75 counterparts of unclassified or poorly studied hard X-ray emitting objects detected with Swift/BAT listed 54-month Palermo BAT catalogue. All these also observations taken Swift/XRT, ROSAT, Chandra satellites, which allowed us to reduce high-energy error box pinpoint most likely counterpart(s). We found that 69 sources our sample are active galactic...
Abstract Accreting supermassive black holes (SMBHs) located at the centers of galaxies are typically surrounded by large quantities gas and dust. The structure evolution this circumnuclear material can be studied different wavelengths, from submillimeter to X-ray. Recent X-ray studies have shown that covering factor obscuring tends decrease with increasing Eddington ratio, likely due radiative feedback on dusty gas. Here we study a sample 549 nearby ( z ≲ 0.1) hard (14–195 keV) selected...
ABSTRACT We investigate the X-ray variability properties of Seyfert 1 Galaxies belonging to BAT AGN Spectroscopic Survey (BASS). The sample includes 151 unobscured (NH &lt; 1022 cm−2) AGNs observed with XMM–Newton for a total exposure time ∼27 ms, representing deepest study done so far high signal-to-noise observations, almost doubling number observations analysed in previous works. constrain relation between normalized excess variance and 2–10 keV luminosities, black hole masses,...
The Vista Variables in the V\'ia L\'actea (VVV) ESO Public Survey is an ongoing time-series, near-infrared (IR) survey of Galactic bulge and adjacent portion inner disk, covering 562 square degrees sky, using ESO's VISTA telescope. has provided superb multi-color photometry 5 broadband filters ($Z$, $Y$, $J$, $H$, $K_s$), leading to best map Milky Way ever obtained, particularly near-IR. main variability part survey, which focused on $K_s$-band observations, currently underway, with fields...
We present one of the largest multiwavelength studies simultaneous optical-to-X-ray spectral energy distributions (SEDs) unobscured ( N H < 10 22 cm −2 ) active galactic nuclei (AGN) in local Universe. Using a representative sample hard-X-ray-selected AGN from 70-month Swift /BAT catalog, with optical/UV photometric data /UVOT and X-ray /XRT, we constructed broadband SEDs 236 nearby (0.001 z 0.3). employed GALFIT to estimate host galaxy contamination determine intrinsic fluxes. used an...
Abstract We analyze Spitzer spectra of 140 active galactic nuclei (AGN) detected in the hard X-rays (14–195 keV) by Burst Alert Telescope on board Swift. This sample allows us to probe several orders magnitude black hole masses (10 6 –10 9 M ⊙ ), Eddington ratios −3 –1), X-ray luminosities 42 45 erg s −1 and column densities 20 24 cm −2 ). The AGN emission is expected be dominant source ionizing photons with energies ≳50 eV, therefore, high-ionization mid-infrared (MIR) lines such as [Ne v ]...
We present the nature of 50 hard X-ray emitting objects unveiled through an optical spectroscopy campaign performed at seven telescopes in northern and southern hemispheres. These were detected with Swift-BAT listed as unidentified 54-month Palermo BAT catalogue. In detail, 45 sources our sample are identified active galactic nuclei which, 27 classified type 1 (with broad narrow emission lines) 18 2 only lines). Among broad-line objects, one is a high-redshift quasi-stellar object, among...
Abstract We present the discovery of PSO J083.8371+11.8482, a weak emission line quasar with extreme star formation rate at z = 6.3401. This was selected from Pan-STARRS1, UHS, and unWISE photometric data. Gemini/GNIRS spectroscopy follow-up indicates Mg ii -based black hole mass <?CDATA ${M}_{\mathrm{BH}}=\left({2.0}_{-0.4}^{+0.7}\right)\times {10}^{9}$?> M ⊙ an Eddington ratio ${L}_{\mathrm{bol}}/{L}_{\mathrm{Edd}}={0.5}_{-0.2}^{+0.1}$?> , in actively accreting supermassive (SMBH) ≳ 6....
The VISTA Variables in the Vía Láctea (VVV) survey is one of six public ESO surveys, and now its 4th year observing. Although far from being complete, VVV has already delivered many results, some directly connected to intended science goals (detection variables stars, microlensing events, new star clusters), others concerning more exotic objects, e.g. novae. Now, at end fourth observing period, comprising roughly 50% proposed observations, actual status survey, as well results based on data,...
We present one of the largest multiwavelength studies simultaneous optical-to-X-ray spectral energy distributions (SEDs) unobscured active galactic nuclei (AGN) in local Universe. Using a representative sample hard-X-ray-selected AGN from 70-month Swift/BAT catalog, with optical/UV photometric data Swift/UVOT and X-ray Swift/XRT, we constructed broadband SEDs 236 nearby (0.001<z<0.3). employed GALFIT to estimate host galaxy contamination determine intrinsic fluxes. used an absorbed power law...