M. A. P. Torres
A5070078630- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Pulsars and Gravitational Waves Research
- Astrophysics and Cosmic Phenomena
- Astronomical Observations and Instrumentation
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Galaxies: Formation, Evolution, Phenomena
- Mechanics and Biomechanics Studies
- Radio Astronomy Observations and Technology
- Astrophysics and Star Formation Studies
- High-pressure geophysics and materials
- Adaptive optics and wavefront sensing
- Geophysics and Gravity Measurements
- Dark Matter and Cosmic Phenomena
- Particle Detector Development and Performance
- Solar and Space Plasma Dynamics
- Relativity and Gravitational Theory
- Astro and Planetary Science
- Particle Accelerators and Free-Electron Lasers
- Neutrino Physics Research
- Particle physics theoretical and experimental studies
- Ionosphere and magnetosphere dynamics
- Geophysics and Sensor Technology
- Cosmology and Gravitation Theories
Universidad de La Laguna
2002-2024
Instituto de Astrofísica de Canarias
2000-2024
Hospital Clínic de Barcelona
2022-2024
Instituto de Astrofísica de Andalucía
2011-2023
Universidad Nacional Autónoma de México
2013-2023
SRON Netherlands Institute for Space Research
2011-2020
Universidad Nacional de Entre Ríos
2020
Radboud University Nijmegen
2014-2019
Consejo Superior de Investigaciones Científicas
2008-2019
Universidad de Zaragoza
2014-2019
The extragalactic background light (EBL) is of fundamental importance both for understanding the entire process galaxy evolution and γ-ray astronomy, but overall spectrum EBL between 0.1 1000 μm has never been determined directly from spectral energy distribution (SED) observations over a wide redshift range. evolving, derived here utilizing novel method based on only. This achieved observed rest-frame K-band luminosity function up to 4, combined with determination galaxy-SED-type fractions....
We present multiband photometry of 185 type-Ia supernovae (SNe Ia), with over 11,500 observations. These were acquired between 2001 and 2008 at the F. L. Whipple Observatory Harvard-Smithsonian Center for Astrophysics (CfA). This sample contains largest number homogeneously observed reduced nearby SNe Ia (z ≲ 0.08) published to date. It more than doubles sample, bringing SN cosmology point where systematic uncertainties dominate. Our natural system has a precision ≲0.02 mag in BVRIr'i' ≲0.04...
The atmospheric Cherenkov gamma-ray telescope MAGIC, designed for a low-energy threshold, has detected very-high-energy gamma rays from giant flare of the distant Quasi-Stellar Radio Source (in short: radio quasar) 3C 279, at distance more than 5 billion light-years (a redshift 0.536). No quasar been observed previously in radiation, and this is also most object emitting above 50 gigaelectron volts. Because high-energy may be stopped by interacting with diffuse background light universe,...
Very high energy (VHE) γ-ray emission from the flat spectrum radio quasar (FSRQ) PKS 1222+21 (4C 21.35, z = 0.432) was detected with MAGIC Cherenkov telescopes during a short observation (∼0.5 hr) performed on 2010 June 17. The detection coincides high-energy MeV/GeV activity measured by Large Area Telescope (LAT) board Fermi satellite. VHE extends about 70 GeV up to at least 400 and can be well described power-law dN/dE ∝ E−Γ photon index Γ 3.75 ± 0.27stat 0.2syst. averaged integral flux...
The binary neutron star merger event GW170817 was detected through both electromagnetic radiation and gravitational waves. Its afterglow emission may have been produced by either a narrow relativistic jet or an isotropic outflow. High-spatial-resolution measurements of the source size displacement can discriminate between these scenarios. We present very-long-baseline interferometry observations, performed 207.4 days after using global network 32 radio telescopes. apparent is constrained to...
We analyze the timing of photons observed by MAGIC telescope during a flare active galactic nucleus Mkn 501 for possible correlation with energy, as suggested some models quantum gravity (QG), which predict vacuum refractive index ≃1+(E/MQGn)n, n=1,2. Parametrizing delay between γ-rays different energies Δt=±τlE or Δt=±τqE2, we find τl=(0.030±0.012) s/GeV at 2.5-σ level, and τq=(3.71±2.57)×10−6 s/GeV2, respectively. use these results to establish lower limits MQG1>0.21×1018 GeV...
One fundamental question about pulsars concerns the mechanism of their pulsed electromagnetic emission. Measuring high-end region a pulsar's spectrum would shed light on this question. By developing new electronic trigger, we lowered threshold Major Atmospheric gamma-ray Imaging Cherenkov (MAGIC) telescope to 25 GeV. In configuration, detected gamma-rays from Crab pulsar that were greater than GeV, revealing relatively high cutoff energy in phase-averaged spectrum. This indicates emission...
We present an improved method for determining the mass of neutron stars in eclipsing X-ray pulsar binaries and apply to six systems, namely Vela X-1, 4U 1538-52, SMC LMC X-4, Cen X-3, Her X-1. In previous studies determine star mass, eclipse duration has been approximated analytically by assuming companion is spherical with effective Roche lobe radius. use a numerical code based on geometry various optimizers analyze published data these which we supplement new spectroscopic photometric...
We present multi-band optical photometry of 94 spectroscopically confirmed Type Ia supernovae (SNe Ia) in the redshift range 0.0055–0.073, obtained between 2006 and 2011. There are a total 5522 light-curve points. show that our natural-system SN has precision ≲ 0.03 mag BVr'i', 0.06 u', 0.07 U for points brighter than 17.5 estimate it systematic uncertainty 0.014, 0.010, 0.012, 0.046, 0.073 BVr'i'u'U, respectively. Comparisons standard-system with published light curves comparison stars...
We measure the spin of XTE J1550−564 using two leading methods: (i) modelling thermal continuum spectrum accretion disc; and (ii) broad red wing reflection fluorescence Fe Kα line. find that these independent measurements are in agreement. For continuum-fitting analysis, we use a data sample consisting several dozen Rossi X-ray Timing Explorer spectra, for pair ASCA spectra from single epoch. Our estimate black hole primary method is −0.11 < a* 0.71 (90 per cent confidence), with most likely...
We present an improved dynamical model of the X-ray binary and microquasar XTE J1550−564 based on new moderate-resolution optical spectroscopy near-infrared photometry obtained with 6.5 m Magellan Telescopes at Las Campanas Observatory. Twelve spectra source were using Echellette Spectrograph between 2008 May 6 August 4. In addition, several hundred images field 2006 2009 July in J KS filters PANIC camera. The agreement 2006/2007 light curves is not perfect, differences can plausibly be...
We present a dynamical model of the high mass X-ray binary LMC X-1 based on high-resolution optical spectroscopy and extensive near-infrared photometry. From our new data we find an orbital period P = 3.90917 ± 0.00005 days. refined analysis All Sky Monitor from RXTE 3.9094 0.0008 days, which is consistent with period. A simple Thomson scattering in stellar wind can account for modulation seen light curves. The V − K color star (1.17 0.05) implies AV 2.28 0.06, much larger than previously...
Aims. We investigate the molecular gas properties of a sample 23 galaxies in order to find and test chemical signatures galaxy evolution compare them IR evolutionary tracers.
We obtained 16 VLT/X-shooter observations of GX 339-4 in quiescence the period May - September 2016 and detected absorption lines from donor star its NIR spectrum. This allows us to measure radial velocity curve projected rotational for first time. confirm 1.76 day orbital we find that $K_2$ = $219 \pm 3$ km s$^{-1}$, $\gamma 26 2$ s$^{-1}$ $v \sin i 64 8$ s$^{-1}$. From these values compute a mass function $f(M) =1.91 0.08~M_{\odot}$, factor $\sim lower than previously reported, ratio $q...
We use Very Long Baseline Interferometry to measure the proper motions of three black hole X-ray binaries (BHXBs). Using these results together with data from literature and Gaia-DR2 collate best available constraints on motion, parallax, distance systemic radial velocity 16 BHXBs, we determined their dimensional Galactocentric orbits. extended this analysis estimate probability distribution for potential kick (PKV) a BHXB system could have received formation. Constraining kicks imparted...
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...
The second data release of the LOFAR Two-Metre Sky Survey (LoTSS) covers 27% northern sky, with a total area ~5700 deg 1 . high angular resolution Dutch baselines (6 arcsec) allows us to carry out optical identifications large fraction detected radio sources without further followup; however, process is made more challenging by many extended found in images as result its excellent sensitivity structure. In this paper we present source associations and for based on near-infrared data, using...
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 report the results of observation nearby satellite galaxy Segue 1 performed by MAGIC-I ground-based gamma-ray telescope between November 2008 and March 2009 for a total 43.2 hours. No significant emission was found above background. Differential upper limits on flux are derived assuming various power-law slopes possible spectrum. Integral also calculated several spectra different energy thresholds. The values order 10^{-11} ph cm^{-2}$ s^{-1} 100 GeV 10^{-12} cm^{-2} 200 GeV. is currently...
The bright X-ray transient H1743−322 was observed daily by the Rossi Timing Explorer during most of its eight-month outburst in 2003. We present a detailed spectral analysis and supporting timing all these data, we discuss behavior evolution source terms three principal states defined Remillard McClintock. These results are complemented Very Large Array data obtained at six frequencies that provide quite complete coverage entire cycle 4.860 GHz 8.460 GHz. also photometric finding charts for...