M. Santos‐Lleó
A5059691604- Astrophysical Phenomena and Observations
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Astronomical Observations and Instrumentation
- Pulsars and Gravitational Waves Research
- Astrophysics and Star Formation Studies
- Adaptive optics and wavefront sensing
- SAS software applications and methods
- Scientific Measurement and Uncertainty Evaluation
- Advanced Measurement and Metrology Techniques
- History and Developments in Astronomy
- Solar and Space Plasma Dynamics
- Scientific Research and Discoveries
- Geophysics and Gravity Measurements
- Mechanics and Biomechanics Studies
- Photocathodes and Microchannel Plates
- Radio Astronomy Observations and Technology
- Spectroscopy and Laser Applications
- Astro and Planetary Science
- Statistical and numerical algorithms
- Particle Accelerators and Free-Electron Lasers
- Atmospheric Ozone and Climate
European Space Astronomy Centre
2014-2024
European Space Agency
2022
Centro Universitário Newton Paiva
2006-2015
Morehead State University
2015
Max Planck Institute for Radio Astronomy
2015
Sapienza University of Rome
2015
Engineering Science Analysis (United States)
2007
European Space Research and Technology Centre
2002
Instituto de Tecnologías Físicas y de la Información “Leonardo Torres Quevedo”
1997-1998
Instituto de Física Fundamental
1996-1997
We present results of a systematic analysis the XMM-Newton spectra 40 quasars (QSOs) () from Palomar-Green (PG) Bright Quasar Survey sample (23). The includes 35 radio-quiet (RQQs) and 5 radio-loud (RLQs). above 2 keV reveals that hard X-ray continuum emission can be modeled with power law component for RQQs RLQs, respectively. Below keV, strong, broad excess is in most QSO spectra. This feature has been fitted four different models assuming several physical scenarios. All tested (blackbody,...
view Abstract Citations (502) References (43) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Steps toward Determination of the Size and Structure Broad-Line Region in Active Galactic Nuclei. I. an 8 Month Campaign Monitoring NGC 5548 with IUE Clavel, J. ; Reichert, G. A. Alloin, D. Crenshaw, M. Kriss, Krolik, H. Malkan, Netzer, Peterson, B. Wamsteker, W. Altamore, Baribaud, T. Barr, P. Beck, S. Binette, L. Bromage, E. Brosch, N. Diaz, Filippenko, V. Fricke,...
Sky surveys produce enormous quantities of data on extensive regions the sky. The easiest way to access this information is through catalogues standardised products. {\em XMM-Newton} has been surveying sky in X-ray, ultra-violet, and optical bands for 20 years. Survey Science Centre producing products facilitate serendipitous X-ray Using improved calibration enhanced software, we re-reduced all 14041 observations, which 11204 observations contained with at least one detection these created a...
view Abstract Citations (284) References (32) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Steps toward Determination of the Size and Structure Broad-Line Region in Active Galactic Nuclei. VIII. an Intensive HST, IUE, Ground-based Study NGC 5548 Korista, K. T. ; Alloin, D. Barr, P. Clavel, J. Cohen, R. Crenshaw, M. Evans, I. N. Horne, Koratkar, A. Kriss, G. Krolik, H. Malkan, Morris, S. L. Netzer, O'Brien, Peterson, B. Reichert, Rodriguez-Pascual,...
The narrow-line Seyfert 1 Galaxy 1H 0707−495 went into a low state from 2010 December to 2011 February, discovered by monitoring campaign using the X-Ray Telescope on Swift satellite. We triggered 100 ks XMM–Newton observation of source in January, revealing have dropped factor 10 soft band, below keV, and 2 at 5 compared with long 2008. sharp spectral drop usually seen around 7 keV now extends lower energies, 6 our frame. spectrum is well fitted relativistically blurred reflection similar...
An 8 month monitoring campaign on the Seyfert 1 galaxy Fairall 9 has been conducted with International Ultraviolet Explorer in an attempt to obtain reliable estimates of continuum-continuum and continuum-emission-line delays for a high-luminosity active galactic nucleus (AGN). While results this are more ambiguous than those previous campaigns lower luminosity sources, we find general agreement earlier results: (1) there is no measurable lag between ultraviolet continuum bands, (2) measured...
The luminous infrared-loud quasar IRAS 13349+2438 was observed with the XMM-Newton Observatory as part of Performance Verification program. spectrum obtained by Reflection Grating Spectrometer (RGS) exhibits broad ( FWHM) absorption lines from highly ionized elements including hydrogen- and helium-like carbon, nitrogen, oxygen, neon, several iron L-shell ions (Fexvii-xx). Also shown in is first astrophysical detection a feature around Åidentified an unresolved transition array (UTA) 2p-3d...
view Abstract Citations (180) References (64) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Multiwavelength Observations of Short-Timescale Variability in NGC 4151. IV. Analysis Continuum Edelson, R. A. ; Alexander, T. Crenshaw, D. M. Kaspi, S. Malkan, Peterson, B. Warwick, Clavel, J. Filippenko, V. Horne, K. Korista, Kriss, G. Krolik, H. Maoz, Nandra, O'Brien, P. Penton, Yaqoob, Albrecht, Alloin, Ayres, Balonek, Barr, Barth, Bertram, Bromage, E. Carini,...
From 1996 June 10 to July 29, the International Ultraviolet Explorer monitored Seyfert 1 galaxy NGC 7469 continuously in an attempt measure time delays between continuum and emission-line fluxes. delays, one can estimate size of region dominating production UV emission lines this source. We find strong respond variations with about 23-31 for Lyα, 27 C IV λ1549, 19-24 N V λ1240, 17-18 Si λ1400, 07-10 He II λ1640. The most remarkable result, however, is detection apparent different bands. With...
In recent years, indirect evidence has emerged suggesting that many nearby nonactive galaxies harbor quiescent supermassive black holes. Knowledge of the frequency occurrence holes, their masses and spins, is broad relevance for studying hole growth galaxy active galactic nuclei formation evolution. It been suggested an unavoidable consequence existence best diagnostic presence in galaxies, would be occasional tidal disruption stars captured by These events manifest themselves form luminous...
We present a XMM–Newton observation of Markarian 304, Seyfert 1 galaxy at z= 0.066. The EPIC data show that MKN 304 is affected by heavy (NH≈ 1023 cm−2) obscuration arising from ionized gas. A two-phase warm absorber provides an adequate parametrization this ionization parameter the two components ξ≈ 6 erg cm−2 s−1 and 90 s−1, respectively. observed continuum photon index (Γ≈ 1.9) typical for galaxies. Two significant emission lines are detected 0.57 keV 6.4 keV, former mostly likely due to...
Accretion models predict that fluorescence lines broadened by relativistic effects should arise from reflection of X-ray emission onto the inner region accretion disc surrounding central black hole active galactic nuclei (AGN). The theory behind origin is well established, and observational evidence a moderate number sources seems to support existence these lines. aim this work establish fraction AGN with Fe Kalpha lines, study possible correlations source physical properties. An XMM-Newton...
We present the results of a 500 ks long XMM–Newton observation and 120 quasi-simultaneous Chandra Narrow-Line Seyfert 1 galaxy 1H 0707−495 performed in 2010 September. Consistent with earlier by Fabian et al. Zoghbi al., spectrum is found to be dominated relativistically broadened reflection features from an ionized accretion disc around maximally rotating black hole. Even though spectra changed between this observations, physical parameters hole (i.e. spin inclination) are consistent both...
We study the X-ray emission of a representative sample 27 local luminous infrared galaxies (LIRGs). The median IR luminosity our is log L_IR/L_sun = 11.2, thus low-luminosity end LIRG class well represented. used new XMM-Newton data as Chandra and archive data. soft (0.5-2 keV) most (>80%), including LIRGs hosting Seyfert 2 nucleus, dominated by star-formation related processes. These follow rate (SFR) versus correlation observed in starbursts. find that ~15% non-Seyfert (3 out 20) have...
Winds outflowing from active galactic nuclei (AGNs) may carry significant amounts of mass and energy out to their host galaxies. In this paper we report the detection a sub-relativistic outflow observed in narrow line Seyfert 1 galaxy IRAS 17020+4544 as series absorption lines corresponding at least five components with an unprecedented wide range associated column densities ionization levels velocities 23,000–33,000 km s−1, detected X-ray high spectral resolution (E/ΔE ∼ 1000) ESA's...
view Abstract Citations (164) References (53) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Steps toward Determination of the Size and Structure Broad-Line Region in Active Galactic Nuclei. V. Variability Ultraviolet Continuum Emission Lines NGC 3783 Reichert, G. A. ; Rodriguez-Pascual, P. M. Alloin, D. Clavel, J. Crenshaw, Kriss, Krolik, H. Malkan, Netzer, Peterson, B. Wamsteker, W. Altamore, Altieri, Anderson, K. S. Blackwell, H., Jr. Boisson, C. Brosch,...
Abstract We present simultaneous XMM–Newton and NuSTAR observations of the repeat changing-look AGN NGC 1566, which dramatically increased in brightness IR to X-ray bands 2018. The broad-band spectrum was taken at peak outburst is typical Seyfert 1 AGN. shows a soft excess, Compton hump, warm absorption reflection, ruling out tidal disruption as cause demonstrating that ‘standard’ accretion disk can develop very rapidly. high-resolution grating reveals has launched ∼500 km s−1 outflow,...
We report the detection of high-amplitude X-ray flaring AGN HE 1136-2304, which is accompanied by a strong increase in flux broad Balmer lines, changing its Seyfert type from almost 2 1993 down to 1.5 2014. 1136-2304 was detected XMM–Newton slew survey at >10 times it had ROSAT all-sky survey, and confirmed with Swift follow-up after increasing factor ∼30. Optical spectroscopy SALT shows that has changed 1.95 galaxy, greatly increased line emission an blue continuum >4. The spectra NuSTAR...
We present a qualitative search for ultra-fast outflows (UFOs) in excess variance spectra of radio-quiet active galactic nuclei (AGN). analyse 42 sources from the Tombesi et al. (2010) spectroscopic UFO detection sample, and an additional 22 different Kara (2016) variability sample. A total 58 have sufficient observational data XMM-Newton EPIC-pn spectrum to be calculated. examine these peaks corresponding variable blue-shifted H- He-like ion absorption lines UFOs. find good evidence such...
Context. NGC 1566 is a local face-on Seyfert galaxy and known for exhibiting recurrent outbursts that are accompanied by changes in spectral type. The most recent transient event occurred from 2017 to 2019 was reported be change classification 1.8 1.2. Aims. We aim study the detail analyzing variations optical broad-line profiles. In particular, we intend determine structure kinematics of region. Methods. analyzed data an spectroscopic variability campaign taken with 9.2 m Southern African...
As part of an extensive multiwavelength monitoring campaign, the International Ultraviolet Explorer satellite was used to observe broad-line radio galaxy 3C 390.3 during period 1994 December 31-1996 March 5. Spectra were obtained every 6-10 days. The UV continuum varied by a factor 7 through while broad emission lines factors 2-5. Unlike previously monitored Seyfert 1 galaxies, in which X-ray generally varies with larger amplitude than UV, light curve is similar both and shape observed...