Subvenciones relacionadas:
General
Los agujeros negros y estrellas de neutrones en binarias de rayos-X son laboratorios únicos para explorar la física de estos objetos compactos. No solo permiten confirmar la existencia de agujeros negros de origen estelar a través de mediciones dinámicas de sus masas, sino que también permiten investigar el comportamiento de la materia y la radiación bajo la influencia de un campo gravitatorio extremo. De este modo, es posible estudiar la física del proceso de acreción, la forma más eficiente de producción de energía conocida. El conocimiento de este proceso es esencial para entender el Universo, jugando un papel crucial en la astronomía galáctica y extra-galáctica.
Los objetivos científicos que se persiguen son:
- Estudios de acreción y eyección. Esta línea explota una fenomenología que nuestro grupo ha descubierto recientemente y se enfoca en la relación universal existente entre el proceso de acreción en agujeros negros y los procesos de expulsión en forma de jets colimados y vientos. Se pondrá énfasis en las propiedades generales y el efecto que el viento frío que hemos descubierto en binarias de rayos-X tiene sobre todo el proceso de acreción. Investigaremos como de comunes son estos vientos, como afectan al proceso de acrecimiento en el agujero negro y cuál es su relación con los jets y los vientos observados en rayos-X. Asimismo se realizarán estudios espectrales detallados en rayos X, con el fin de caracterizar los diferentes estados y geometrías de acreción en función de la luminosidad.
- Tenemos como objetivo definir la distribución de masas de agujeros negros estelares y estrellas de neutrones. Para ello medimos masas en binarias de rayos-X, continuando así nuestra ya reconocida contribución a uno de los experimentos fundamentales en la astrofísica moderna. De este modo, esperamos mejorar significativamente las distribuciones conocidas de objetos compactos, lo cual permitirá verificar modelos de explosión de supernovas y evolución de binarias compactas; además de obtener límites a la ecuación de estado de la materia nuclear. Para ello, mediremos las masas en binarias de rayos-X conocidas o recientemente descubiertas, e intentaremos encontrar un gran número de nuevas binarias de rayos X en nuestra galaxia que puedan después ser estudiadas dinámicamente.
- Analizar la estructura y variabilidad de los discos de acreción alrededor de los objetos compactos en diferentes bandas espectrales (óptico-rayos X). La distribución espectral durante la erupción (especialmente a altas energías) y su variación temporal es esencial para restringir los modelos de erupción y la estructura física del disco (e.g. radio del disco advectivo) así como la contribución del jet a la emisión en el visible y el infrarrojo.
Miembros
Resultados
- Nuestro equipo ha liderado un ambicioso estudio multi-frecuencia que cubrió las dos erupciones de 2015 del agujero negro transitorio V404 Cyg. Este evento ha sido uno de los más interesantes jamás observados de este tipo. En 2018 publicamos el trabajo global que recoge todos los datos espectroscópicos tomados en 1989 y 2015.
- Presentamos la evidencia de viento similar al detectado en V404 Cyg en un segundo sistema con agujero negro, V4641 Sgr.
- Se publicó tanto el artículo final como un estudio piloto sobre el método desarrollado por el grupo para descubrir y medir masas en agujeros negros en quietud. Esta técnica, potencialmente, podría triplicar la población conocida de estos objetos.
- Se medió la masa de la estrella de neutrones en PSR J2215+5135, una de las más masivas que se conocen hasta la fecha.
- Se presentó el primer estudio detallado del sistema ultra-compacto SLX 1737-282.
Actividad científica
Publicaciones relacionadas
-
The OmegaWhite Survey for Short-period Variable Stars. V. Discovery of an Ultracompact Hot Subdwarf Binary with a Compact Companion in a 44-minute OrbitWe report the discovery of the ultracompact hot subdwarf (sdOB) binary OW J074106.0–294811.0 with an orbital period of {P}{orb}=44.66279+/- 1.16× {10}-4 minutes, making it the most compact hot subdwarf binary known. Spectroscopic observations using the VLT, Gemini and Keck telescopes revealed a He-sdOB primary with an intermediate helium abundanceKupfer, T. et al.
Fecha de publicación:
122017 -
An elevation of 0.1 light-seconds for the optical jet base in an accreting Galactic black hole systemRelativistic plasma jets are observed in many systems that host accreting black holes. According to theory, coiled magnetic fields close to the black hole accelerate and collimate the plasma, leading to a jet being launched1-3. Isolating emission from this acceleration and collimation zone is key to measuring its size and understanding jetGandhi, P. et al.
Fecha de publicación:
122017 -
The white dwarf binary pathways survey - II. Radial velocities of 1453 FGK stars with white dwarf companions from LAMOST DR 4We present the second paper of a series of publications aiming at obtaining a better understanding regarding the nature of type Ia supernovae (SN Ia) progenitors by studying a large sample of detached F, G and K main-sequence stars in close orbits with white dwarf companions (i.e. WD+FGK binaries). We employ the Large Sky Area Multi-Object FibreRebassa-Mansergas, A. et al.
Fecha de publicación:
122017 -
Properties of the redback millisecond pulsar binary 3FGL J0212.1+5320Linares et al. obtained quasi-simultaneous g΄-, r΄- and i΄-band light curves and an absorption-line radial velocity curve of the secondary star in the redback system 3FGL J0212.1+5320. The light curves showed two maxima and minima primarily due to the secondary star's ellipsoidal modulation, but with unequal maxima and minima. We fit these lightShahbaz, T. et al.
Fecha de publicación:
122017 -
The Mass Function of GX 339–4 from Spectroscopic Observations of Its Donor StarWe obtained 16 VLT/X-shooter observations of GX 339‑4 in quiescence during the period 2016 May–September and detected absorption lines from the donor star in its NIR spectrum. This allows us to measure the radial velocity curve and projected rotational velocity of the donor for the first time. We confirm the 1.76 day orbital period and we find thatHeida, M. et al.
Fecha de publicación:
92017 -
Testing the white dwarf mass-radius relationship with eclipsing binariesWe present high-precision, model-independent, mass and radius measurements for 16 white dwarfs in detached eclipsing binaries and combine these with previously published data to test the theoretical white dwarf mass-radius relationship. We reach a mean precision of 2.4 per cent in mass and 2.7 per cent in radius, with our best measurements reachingParsons, S. G. et al.
Fecha de publicación:
102017 -
Spectroscopic classification of X-ray sources in the Galactic Bulge SurveyWe present the classification of 26 optical counterparts to X-ray sources discovered in the Galactic Bulge Survey. We use (time-resolved) photometric and spectroscopic observations to classify the X-ray sources based on their multiwavelength properties. We find a variety of source classes, spanning different phases of stellar/binary evolution. WeWevers, T. et al.
Fecha de publicación:
102017 -
Two white dwarfs in ultrashort binaries with detached, eclipsing, likely sub-stellar companions detected by K2Using data from the extended Kepler mission in K2 Campaign 10, we identify two eclipsing binaries containing white dwarfs with cool companions that have extremely short orbital periods of only 71.2 min (SDSS J1205-0242, a.k.a. EPIC 201283111) and 72.5 min (SDSS J1231+0041, a.k.a. EPIC 248368963). Despite their short periods, both systems areParsons, S. G. et al.
Fecha de publicación:
102017 -
Multiband study of RX J0838-2827 and XMM J083850.4-282759: a new asynchronous magnetic cataclysmic variable and a candidate transitional millisecond pulsarIn a search for the counterpart to the Fermi-LAT source 3FGL J0838.8-2829, we performed a multiwavelength campaign: in the X-ray band with Swift and XMM-Newton; in the infrared and optical with OAGH, ESO-NTT and IAC80; and in the radio with ATCA observations. We also used archival hard X-ray data obtained by INTEGRAL. We report on three X-rayCasares, J. et al.
Fecha de publicación:
112017 -
PTF1 J085713+331843, a new post-common-envelope binary in the orbital period gap of cataclysmic variablesWe report the discovery and analysis of PTF1 J085713+331843, a new eclipsing post-common-envelope detached white-dwarf-red-dwarf binary with a 2.5 h orbital period discovered by the Palomar Transient Factory. ULTRACAM multicolour photometry over multiple orbital periods reveals a light curve with a deep flat-bottomed primary eclipse and a strongLaher, R. et al.
Fecha de publicación:
72017 -
Once in a blue moon: detection of `bluing' during debris transits in the white dwarf WD 1145+017The first transiting planetesimal orbiting a white dwarf was recently detected in K2 data of WD 1145+017 and has been followed up intensively. The multiple, long and variable transits suggest the transiting objects are dust clouds, probably produced by a disintegrating asteroid. In addition, the system contains circumstellar gas, evident by broadHallakoun, N. et al.
Fecha de publicación:
82017 -
A polarized fast radio burst at low Galactic latitudeWe report on the discovery of a new fast radio burst (FRB), FRB 150215, with the Parkes radio telescope on 2015 February 15. The burst was detected in real time with a dispersion measure (DM) of 1105.6 ± 0.8 pc cm-3, a pulse duration of 2.8^{+1.2}_{-0.5} ms, and a measured peak flux density assuming that the burst was at beam centre of 0.7^{+0.2}_{Romoli, C. et al.
Fecha de publicación:
82017 -
Flares, wind and nebulae: the 2015 December mini-outburst of V404 CygniAfter more than 26 years in quiescence, the black hole transient V404 Cyg went into a luminous outburst in 2015 June, and additional activity was detected in late December of the same year. Here, we present an optical spectroscopic follow-up of the December mini-outburst, together with X-ray, optical and radio monitoring that spanned more than aCasares, J. et al.
Fecha de publicación:
22017 -
The puzzling case of the accreting millisecond X-ray pulsar IGR J00291+5934: flaring optical emission during quiescenceWe present an optical (gri) study during quiescence of the accreting millisecond X-ray pulsar IGR J00291+5934 performed with the 10.4 m Gran Telescopio Canarias (GTC) in August 2014. Although the source was in quiescence at the time of our observations, it showed a strong optical flaring activity, more pronounced in bluer filters (i.e. the g-band)Baglio, M. C. et al.
Fecha de publicación:
42017 -
Suzaku spectroscopy of the neutron star transient 4U 1608-52 during its outburst decay.We test the proposed three-component spectral model for neutron star low-mass X-ray binaries using broad-band X-ray data. We have analysed four X-ray spectra (0.8-30 keV) obtained with Suzaku during the 2010 outburst of 4U 1608-52, which have allowed us to perform a comprehensive spectral study covering all the classical spectral states. We use aArmas Padilla, M. et al.
Fecha de publicación:
52017 -
SDSS J105754.25+275947.5: a period-bounce eclipsing cataclysmic variable with the lowest-mass donor yet measuredWe present high-speed, multicolour photometry of the faint, eclipsing cataclysmic variable (CV) SDSS J105754.25+275947.5. The light from this system is dominated by the white dwarf. Nonetheless, averaging many eclipses reveals additional features from the eclipse of the bright spot. This enables the fitting of a parametrized eclipse model to theseMcAllister, M. J. et al.
Fecha de publicación:
52017 -
Swift and SALT observations of the multiple outbursts of MAXI J1957+032The new recurrent X-ray transient MAXI J1957+032 has had four X-ray outbursts within 16 months, all very briefly detected (lastingMata-Sanchez, D. et al.
Fecha de publicación:
62017 -
Links between quasi-periodic oscillations and accretion states in neutron star low-mass X-ray binariesWe analysed the Rossi X-ray Timing Explorer data from a sample of bright accreting neutron star (NS) low-mass X-ray binaries (LMXBs). With the aim of studying the quasi-periodic variability as a function of the accretion regime, we carried out a systematic search of the quasi-periodic oscillations (QPOs) in the X-ray time series of these systemsMotta, S. E. et al.
Fecha de publicación:
62017 -
Potential cooling of an accretion-heated neutron star crust in the low-mass X-ray binary 1RXS J180408.9-342058We have monitored the transient neutron star low-mass X-ray binary 1RXS J180408.9-342058 in quiescence after its ∼4.5 month outburst in 2015. The source has been observed using Swift and XMM-Newton. Its X-ray spectra were dominated by a thermal component. The thermal evolution showed a gradual X-ray luminosity decay from ∼18 × 1032 to ∼4 × 1032 (DParikh, A. S. et al.
Fecha de publicación:
42017 -
A VLT-ULTRACAM study of the fast optical quasi-periodic oscillations in the polar V834 CentauriQuasi-periodic oscillations (QPOs) of a few seconds have been detected in some polars, the synchronised subclass of cataclysmic systems containing a strongly magnetised white dwarf which accretes matter from a red dwarf companion. The QPOs are thought to be related to instabilities of a shock formed in the accretion column, close to the white dwarfMouchet, M. et al.
Fecha de publicación:
32017