A5086310735- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- Mechanics and Biomechanics Studies
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- High-pressure geophysics and materials
- Astrophysics and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Adaptive optics and wavefront sensing
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Solar and Space Plasma Dynamics
- Galaxies: Formation, Evolution, Phenomena
- SAS software applications and methods
- Geophysics and Gravity Measurements
- Radio Astronomy Observations and Technology
- Heat Transfer Mechanisms
- Relativity and Gravitational Theory
- Atomic and Molecular Physics
- Particle Detector Development and Performance
- Calibration and Measurement Techniques
- Rare-earth and actinide compounds
- CCD and CMOS Imaging Sensors
- Particle Accelerators and Free-Electron Lasers
Instituto de Astrofísica de Canarias
2015-2024
Universidad de La Laguna
2015-2024
University of Oxford
2014-2018
University of Southampton
2012-2018
University of Amsterdam
2016
Centrum Badań Kosmicznych
2016
Max Planck Institute for Extraterrestrial Physics
2016
Institute for Space Astrophysics and Planetology
2014
Brera Astronomical Observatory
2009-2013
National Institute for Astrophysics
2010-2011
During the last ~50 years, population of black hole candidates in X-ray binaries has increased considerably with 59 Galactic objects detected transient low-mass binaries, plus a few persistent systems (including ~5 extragalactic binaries). We collect near-infrared, optical and information spread over hundreds references order to study holes transients as whole. present most updated catalogue transients, which contains X-ray, near-infrared observations together their astrometric dynamical...
We present a systematic analysis of the fast time variability properties transient black hole binary GRO J1655-40, based on complete set RossiXTE observations. demonstrate that frequencies quasi-periodic oscillations and broad band noise components their variations match accurately strong field general relativistic particle motion in close vicinity innermost stable circular orbit, as predicted by precession model. obtain high precision measurements mass (M = (5.31 +/- 0.07) M solar masses,...
Abstract Black hole X-ray binaries exhibit different spectral and timing properties in accretion states. The outburst of a recently discovered extraordinarily bright source, Swift J1727.8–1613, has enabled the first investigation how polarization source evolve with state. 2–8 keV degree was previously measured by Imaging Polarimetry Explorer (IXPE) to be ≈4% hard intermediate Here we present new IXPE results taken soft state, flux dominated thermal disk emission. We find that dropped...
We analyzed RXTE/PCA and HEXTE data of the transient black hole binary GX 339-4, col- lected over a time span eight years. studied properties behavior low frequency quasi periodic oscillations (QPOs) as function integrated broad-band variability spectral parameters during four outbursts (2002, 2004, 2007, 2010). Most QPOs could be classified following ABC classification that has been proposed before. Our results show can extended to include dependencies three QPO types have indeed...
We present a systematic study of the orbital inclination effects on black-hole transients fast time-variability properties. have considered all binaries that been densely monitored by Rossi XTE satellite. find amplitude low-frequency quasi periodic oscillations (QPOs) depends inclination. Type-C QPOs are stronger for nearly edge-on systems (high inclination), while type-B when accretion disk is closer to face-on (low inclination). Our results also suggest noise associated with type-C...
We have systematically studied a large sample of the neutron star low mass X-ray binaries (LMXBs) monitored by Rossi Timing Explorer (50 sources; 10000+ observations). find that hysteresis patterns between Compton dominated and thermal states, typically observed in black hole LMXBs, are also common systems. These patterns, which intermediate found when looking at evolution both colour fast variability ten systems accreting below ~ 30 % Eddington Luminosity. show does not require changes...
The nature of accretion onto stellar mass black holes in the low/hard state remains unresolved, with some evidence suggesting that inner disc is truncated and replaced by a hot flow. However, detection relativistic broadened Fe emission lines, even at relatively low luminosities, seems to require an extending fully its innermost stable circular orbit. Modelling such features however highly susceptible degeneracies, which could easily bias any interpretation. We present first systematic study...
We present intermediate resolution spectroscopy of the optical counterpart to black hole X-ray transient MAXI J1820+070 (=ASASSN-18ey) obtained with OSIRIS spectrograph on 10.4-m Gran Telescopio Canarias. The observations were performed source close quiescent state and before onset renewed activity in August 2019. make use these data K-type dwarf templates taken same instrumental configuration measure projected rotational velocity donor star. find $v_{rot} \sin i = 84 \pm 5$ km s$^{-1}$...
We present time-resolved 10.4-m GTC and 4.2-m WHT intermediate resolution spectroscopy of the X-ray transient MAXI J1820+070 (=ASASSN-18ey) obtained during its decline to quiescent state. Cross-correlation 21 individual spectra against late-type templates reveals a sinusoidal velocity modulation with period 0.68549 +/- 0.00001 d semi-amplitude 417.7 3.9 km/s. derive mass function f(M) = 5.18 0.15 Msun, dynamically confirming black hole nature compact object. Our analysis stellar absorption...
We present 20 epochs of optical spectroscopy obtained with the GTC-10.4m telescope across bright discovery outburst black hole candidate Swift J1727.8−162. The spectra cover main accretion states and are characterised by presence hydrogen helium emission lines, commonly observed in these objects. They show complex profiles, including double peaks, but also blue-shifted absorptions (with blue-edge velocities 1150 km s −1 ), broad wings, flat-top which usual signatures disc winds. Moreover,...
We present the rms-intensity diagram for black hole transients. Using observations taken with Rossi X-ray timing explorer we study relation between root mean square (rms) amplitude of variability and net count-rate during 2002, 2004 2007 outbursts binary GX 339-4. find that rms-flux previously observed hard state in binaries does not hold other states, when different relations apply. These can be used as a good tracer accretion regimes. identify hard, soft intermediate states diagram....
We studied the low-frequency quasi-periodic oscillations (LFQPOs) in black hole GRO J1655−40 during 2005 outburst, using data from Rossi X-ray Timing Explorer. All LFQPOs could be identified as either type B or C previously proposed classification schemes. In soft state of outburst type-C reached frequencies that are among highest ever seen for holes. At peak ultraluminous state, power spectrum showed two simultaneous, non-harmonically related peaks which we a type-B and QPO. The...
We report on the first 180 days of Rossi X-Ray Timing Explorer observations outburst black hole candidate IGR J17091–3624. This source exhibits a broad variety complex light curve patterns including periods strong flares alternating with quiet intervals. Similar in X-ray curves have been seen (up to now) unique system GRS 1915+105. In context variability classes defined by Belloni et al. for 1915+105, we find that J17091–3624 shows ν, ρ, α, λ, β, and μ as well which resemble χ class, all...
We present a systematic analysis of the complete set observations black hole (BH) binary XTE J1550-564 obtained by Rossi X-ray Timing Explorer. study fast time variability properties source and determine spin through relativistic precession model. Similarly to what is observed in BH GRO J1655-40, frequencies QPOs broad band noise components match general particle motion close compact object predicted The combination two simultaneously quasi-periodic oscillation (QPO) together with dynamical...
Stellar-mass black holes (BHs) are mostly found in X-ray transients, a subclass of binaries that exhibit violent outbursts. None the 50 Galactic BHs known show eclipses, which is surprising for random distribution inclinations. Swift J1357.2-0933 very faint transient detected 2011. On basis spectroscopic evidence, we it contains BH 2.8 h orbital period. Further, high-time resolution optical light curves display profound dips without counterparts. The observed properties best explained by...
MAXI J1659-152 is a bright X-ray transient black-hole candidate binary system discovered in September 2010. We report here on MAXI, RXTE, Swift, and XMM-Newton observations during its 2010/2011 outburst. find that the first one half week of outburst light curves display drops intensity at regular intervals, which we interpret as absorption dips. About three weeks into outbursts, again are seen. These dips have, however, spectral behaviour opposite to dips, related fast state changes (hence...
We report results obtained from a systematic analysis of X-ray lags in sample black hole binaries, with the aim assessing presence reverberation and studying their evolution during outburst. used XMM-Newton simultaneous Rossi Timing Explorer (RXTE) observations to obtain broadband energy coverage both disk hard Comptonization components. In most cases detection is hampered by low levels variability-power signal-to-noise ratio (typically when source soft state) and/or short exposure times....
We present a study of the X-ray flaring activity Sgr A⋆ during all 150 XMM–Newton and Chandra observations pointed at Milky Way centre over last 15 years. This includes latest campaigns devoted to monitoring closest approach very red Brγ emitting object called G2. The entire data set analysed extends from 1999 September through 2014 November. employed Bayesian block analysis investigate any possible variations in characteristics (frequency, energetics, peak intensity, duration) events that...
Understanding the dynamics behind black hole state transitions and changes they reflect in outbursts has become long-standing problem. The X-ray reflection spectrum describes interaction between hard source (the power-law continuum) cool accretion disc it illuminates, thus permits an indirect view of how two evolve. We present a systematic analysis throughout three (500+ observations) binary GX 339−4, representing largest study applying self-consistent treatment to date. Particular attention...
Abstract We report on a detailed optical spectroscopic follow-up of the black hole (BH) transient MAXI J1820+070 (ASASSN-18ey). The observations cover main part X-ray binary outburst, when source alternated between hard and soft states following classical pattern widely seen in other systems. focus analysis He i emission lines at 5876 6678 Å, as well H α . detect clear accretion disk wind features (P-Cyg profiles broad line wings) state, both during outburst rise decay. These are not...
We present observations of rapid (sub-second) optical flux variability in V404 Cyg during its 2015 June outburst. Simultaneous three-band with the ULTRACAM fast imager on four nights show steep power spectra dominated by slow variations ∼100–1000 s time-scales. Near peak outburst 26, a dramatic change occurs and additional, persistent sub-second flaring appears close time to giant radio X-ray flaring. The flares reach luminosities ∼ few × 1036 erg s−1. Some are unresolved down resolution 24...