A5065492071- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Pulsars and Gravitational Waves Research
- Astronomical Observations and Instrumentation
- Mechanics and Biomechanics Studies
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Astronomy and Astrophysical Research
- High-pressure geophysics and materials
- Geophysics and Gravity Measurements
- Galaxies: Formation, Evolution, Phenomena
- Particle Detector Development and Performance
- SAS software applications and methods
- Astro and Planetary Science
- Earthquake Detection and Analysis
- Atmospheric and Environmental Gas Dynamics
- Adaptive optics and wavefront sensing
- Methane Hydrates and Related Phenomena
- Geophysics and Sensor Technology
- Geochemistry and Geologic Mapping
- Optical Systems and Laser Technology
- Nuclear Physics and Applications
- Astrophysics and Star Formation Studies
- Geological and Geophysical Studies
- Time Series Analysis and Forecasting
Instituto de Astrofísica de Canarias
2014-2024
Universidad de La Laguna
2014-2024
Armagh Observatory & Planetarium
2024
University of Leicester
2024
University of Manchester
2017-2023
Centro de Excelencia en Procesos y Productos de Córdoba
2019
SRON Netherlands Institute for Space Research
2018
Centre de Recerca Matemàtica
2013
Detections of fast X-ray transients (FXTs) have been accrued over the last few decades. However, their origin has remained mysterious. There is now rapid progress thanks to timely discoveries and localisations with Einstein Probe mission. Early results indicate that FXTs may frequently, but not always, be associated gamma-ray bursts (GRBs). Here, we report on multi-wavelength counterpart FXT EP240414a, which no reported counterpart. The transient located 25.7~kpc in projection from a massive...
ABSTRACT We present new medium resolution, optical long-slit spectra of a sample six ultraviolet (UV)/optical and 17 X-ray-selected tidal disruption event candidate host galaxies. measure emission line ratios from the spectra, finding that large majority hosts are quiescent galaxies, while those displaying lines generally consistent with star formation dominated environments; only three sources show clear evidence nuclear activity. bulge velocity dispersions using absorption infer black hole...
ABSTRACT We report the results of optical follow-up observations 29 gravitational-wave (GW) triggers during first half LIGO–Virgo Collaboration (LVC) O3 run with Gravitational-wave Optical Transient Observer (GOTO) in its prototype 4-telescope configuration (GOTO-4). While no viable electromagnetic (EM) counterpart candidate was identified, we estimate our 3D (volumetric) coverage using test light curves on- and off-axis gamma-ray bursts kilonovae. In cases where source region observable...
ABSTRACT The Gravitational-wave Optical Transient Observer (GOTO) is an array of wide-field optical telescopes, designed to exploit new discoveries from the next generation gravitational wave detectors (LIGO, Virgo, and KAGRA), study rapidly evolving transients, multimessenger opportunities arising neutrino very high energy gamma-ray triggers. In addition a rapid response mode, will also perform sensitive, all-sky transient survey with few day cadence. facility features novel, modular design...
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,...
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...
ABSTRACT We present the results of a large multiwavelength follow-up campaign tidal disruption event (TDE) AT 2019dsg, focusing on low to high resolution optical spectroscopy, X-ray, and radio observations. The galaxy hosts super massive black hole mass $\rm (5.4\pm 3.2)\times 10^6\, M_\odot$ careful analysis finds no evidence for presence an active galactic nucleus, instead TDE host shows narrow emission lines that likely arise from star formation activity. transient is luminous in X-rays,...
Abstract Reliable neutron star mass measurements are key to determining the equation of state cold nuclear matter, but such rare. Black widows and redbacks compact binaries consisting millisecond pulsars semi-degenerate companion stars. Spectroscopy optically bright companions can determine their radial velocities, providing inclination-dependent pulsar estimates. Although inclinations be inferred from subtle features in optical light curves, estimates may systematically biased due...
ABSTRACT Black widows are extreme millisecond pulsar binaries where the wind ablates their low-mass companion stars. In optical range, light curves vary periodically due to high irradiation and tidal distortion of companion, which allows us infer binary parameters. We present simultaneous multiband observations obtained with HIPERCAM instrument at 10.4-m GTC telescope for six these systems. The combination this five-band (us,gs, rs, is, zs) fast photometer world’s largest enables inspect...
Fully integrated monitoring systems have shown promise in improving confidence composite materials while reducing lifecycle costs. A distributed optical fibre sensor is embedded a reinforced laminate, to give three sensing regions at different levels through-the-thickness of the plate. This study follows resin infusion process during fabrication composite, development strain in-situ and real time, gain better understanding rheology curing. Piezoelectric wafer active sensors electrical gauges...
Swift J1357.2-0933 is one of the shortest orbital period black hole X-ray transients (BHTs). It exhibited deep optical dips together with an extremely broad H$α$ line during outburst. We present 10.4-m GTC time-resolved spectroscopy quiescence searching for donor star absorption features. The large contribution accretion flow to total luminosity prevents direct detection companion. Nevertheless, we constrain non-stellar be larger than $\sim 80\%$ light, which sets new lower limits distance...
The Fermi Large Area Telescope gamma-ray source 3FGL J2039.6$-$5618 contains a periodic optical and X-ray that was predicted to be "redback" millisecond pulsar (MSP) binary system. However, the conclusive identification required detection of pulsations from putative MSP. To better constrain orbital parameters for directed search pulsations, we obtained new light curves in 2017 2018, which revealed long-term variability companion star. resulting parameter constraints were used perform...
Binaries harbouring millisecond pulsars enable a unique path to determine neutron star masses: radio pulsations reveal the motion of star, while that companion can be characterised through studies in optical range. PSR J1012+5307 is pulsar 14.5-h orbit with helium-core white dwarf companion. In this work we present analysis an spectroscopic campaign, where absorption features one lightest known dwarfs. We radial velocity semi-amplitude K_2 = 218.9 +- 2.2 km/s, which combined derived from...
We present twelve epochs of optical spectroscopy taken across the discovery outburst black hole candidate MAXI J1803-298 with GTC and VLT telescopes. The source followed a standard evolution hard soft states. system displays triangular shape in hardness intensity diagram, consistent that seen high inclination transients previously reported detection X-ray dips. two observed during initial state exhibited asymmetric emission line profiles, including P-Cygni profile simultaneously detected...
ABSTRACT Accurate measurements of the masses neutron stars are necessary to test binary evolution models, and constrain star equation state. In pulsar binaries with no measurable post-Keplerian parameters, this requires an accurate estimate system’s inclination radial velocity companion by other means than timing. paper, we present results a new method for measuring using synthesis code Icarus. This relies on constructing model spectrum tidally distorted, irradiated as viewed given...
The X-ray transient Swift J1727.8$-$1613 ended its 10-month discovery outburst in June of 2024, when it reached an optical brightness comparable to pre-discovery magnitudes. With the aim performing a dynamical study, we launched spectroscopy campaign with GTC telescope. We detected companion star and constructed radial velocity curve, yielding binary orbital period $P_ orb h $ semi-amplitude $K_ km\ $. This results mass function $f(M_ odot Combined constraints on inclination, sets lower...
After more than 26 years in quiescence, the black hole transient V404 Cyg went into a luminous outburst June 2015, and additional activity was detected late December of same year. Here, we present an optical spectroscopic follow-up mini-outburst, together with X-ray, radio monitoring that spanned month. Strong flares gradually increasing intensity are three spectral ranges during ~10 days following Swift trigger. Our spectra reveal presence fast outflowing wind, as implied by detection P-Cyg...
ABSTRACT Large-scale sky surveys have played a transformative role in our understanding of astrophysical transients, only made possible by increasingly powerful machine learning-based filtering to accurately sift through the vast quantities incoming data generated. In this paper, we present new real-bogus classifier based on Bayesian convolutional neural network that provides nuanced, uncertainty-aware classification transient candidates difference imaging, and demonstrate its application...
Abstract The low-mass X-ray binary Aquila X-1 is one of the most active neutron star transients. Despite its relatively bright quiescent optical counterpart, detection companion has been hampered by presence a nearby interloper star. Using Spectrograph for INtegral Field Observations in Near Infrared (SINFONI) on Very Large Telescope-8.2m telescope, we unambiguously single out from interloper. Phase-resolved near-infrared spectroscopy reveals absorption features K4 ± 2 moving at projected...
Abstract We present the discovery of an optical accretion disk wind in X-ray transient Swift J1858.6-0814. Our 90-spectrum data set, taken with 10.4 m Gran Telescopio Canarias telescope over eight different epochs and across five months, reveals presence conspicuous P-Cyg profiles He i at 5876 Å H α . These features are detected throughout entire campaign, albeit their intensity main observational properties observed to vary on timescales as short 5 minutes. In particular, we observe...
MAXI J1348–630 is a low mass X-ray binary discovered in 2019 during bright outburst. During this event, the system experienced both hard and soft states following standard evolution. We present multi-epoch optical near-infrared spectroscopy obtained with X-shooter at Very Large Telescope. Our dataset includes spectra taken brightest phases of outburst as well decay towards quiescence. study evolution main emission lines, paying special attention to presence features commonly associated...
GX 339–4 is one of the prototypical black hole X-ray transients, exhibiting recurrent outbursts that allow detailed studies accretion and ejection phenomena. In this work we present four epochs optical near-infrared spectroscopy obtained with X-shooter at Very Large Telescope. The dataset includes two hard state spectra, collected during 2013 2015 outbursts, soft spectra observed 2021 outburst. Strong Balmer, Paschen, He I II emission lines are consistently in all while Brackett transitions...
GX 339$-$4 is one of the prototypical black hole X-ray transients, exhibiting recurrent outbursts that allow detailed studies accretion and ejection phenomena. In this work we present four epochs optical near-infrared spectroscopy obtained with X-shooter at Very Large Telescope. The dataset includes two hard state spectra, collected during 2013 2015 outbursts, soft spectra observed 2021 outburst. Strong Balmer, Paschen, He I II emission lines are consistently in all while Brackett...