Black holes, neutron stars, white dwarfs and their local environment

    General
    Description

    Accreting black-holes and neutron stars in X-ray binaries provide an ideal laboratory for exploring the physics of compact objects, yielding not only confirmation of the existence of stellar mass black holes via dynamical mass measurements, but also the best opportunity for probing high-gravity environments and the physics of accretion; the most efficient form of energy production known. The latter is an essential physical process to understand the universe, playing a crucial role in galactic and extra-galactic astronomy.

    This project has the following scientific goals:

    - X-ray binaries offer the opportunity to study accretion as its best, since their relevant changes occur on convenient time-scales for human beings. This project focuses on the universal relation between black-hole accretion and ejection processes in the form of collimated jets and wide-angle winds. We will focus on the general properties and astrophysical impact of the cold optical accretion disc wind that our group has discovered. We want to understand how frequent these winds are, which is their impact in the black-hole accretion process, and what is their relation with jets and hot X-ray winds. Likewise, we carry out very detailed X-ray spectral studies on the different accretion states and geometries and their evolution with luminosity.

    - We want to define the mass distribution of black-holes and neutron stars. Thus, we continue our contribution to one of the fundamental experiments in modern astrophysics by measuring dynamical masses in X-ray binaries. We expect to significantly improve the observed mass distribution of compact objects. This will allow testing models of supernovae explosions and close binary evolution as well as setting constraints on the equation of state of nuclear matter. We will measure masses in newly discovered or known transient X-ray binaries. In addition, we will also search for the large number of dormant X-ray binaries expected in the Galaxy and suitable for dynamical studies.

    - To study the structure of accretion discs in different energy bands (optical-X rays). The high energy spectral distribution and time variability during outburst is important to constrain the eruption models and accretion disc properties (e.g. radius of advective disc) as well as to constrain the contribution of the jet to the optical and infrared emission of the system.

     

    see group web page:  https://research.iac.es/proyecto/compactos/pages/en/introduction.php

    Principal investigator
    1. Our team has led the multi-wavelength study of the two 2015 outbursts of the Black-hole transient V404 Cyg. In 2018, we published a global paper which include all the spectroscopy taken during the 1989 and 2015 campaigns.
    2. We have presented solid evidence for the presence of very similar wind to that found in V404 Cyg in another black hole transient, V4641 Sgr.
    3. We published the final paper as well as a pilot study on a novel method developed by the group. It aims at discovering and measuring masses of black hole transient in quiescence. This method has the potential of increasing the known population of these systems by a factor of three.
    4. We measured the mass of the neutron star in PSR J2215+5135 and found it is one of the heaviest known to date.
    5. We presented the first detailed study on the ultra-compact system SLX 1737-282.

    Related publications

    • Fast infrared winds during the radio-loud and X-ray obscured stages of the black hole transient GRS 1915+105

      The black hole transient GRS 1915+105 entered a new phase of activity in 2018, generally characterised by low X-ray and radio fluxes. This phase has only been interrupted by episodes of strong and variable radio emission, where high levels of X-ray absorption local to the source were measured. We present 18 epochs of near-infrared spectroscopy

      Sánchez-Sierras, J. et al.

      Advertised on:

      12
      2023
      Citations
      0
    • Hβ spectroscopy of the high-inclination black hole transient Swift J1357.2−0933 during quiescence

      Swift J1357.2−0933 is a transient low-mass X-ray binary hosting a stellar-mass black hole. The source exhibits optical dips and very broad emission lines during both outburst and quiescence, which are thought to be the result of a high orbital inclination. We present phase-resolved spectroscopy obtained with the 10.4 m Gran Telescopio Canarias (GTC

      Corral-Santana, J. M. et al.

      Advertised on:

      11
      2023
      Citations
      0
    • An infrared FWHM-K<SUB>2</SUB> correlation to uncover highly reddened quiescent black holes

      Among the sample of Galactic transient X-ray binaries (SXTs) discovered to date, about 70 have been proposed as likely candidates to host a black hole. Yet, only 19 have been dynamically confirmed. Such a reliable confirmation requires phase-resolved spectroscopy of their companion stars, which is generally feasible when the system is in a

      Cúneo, V. A. et al.

      Advertised on:

      11
      2023
      Citations
      0
    • Unveiling optical signatures of outflows in accreting white dwarfs

      Accreting white dwarfs are known to show signatures of wind-type outflows in the ultraviolet. However, at optical wavelengths, wind detections have only been reported for a few sources. We present GTC-10.4 m optical spectroscopy of four accreting white dwarfs (BZ Cam, V751 Cyg, MV Lyr, and V425 Cas) observed during luminous epochs, when their

      Cúneo, V. A. et al.

      Advertised on:

      11
      2023
      Citations
      0
    • The orbital period of the recurrent nova V2487 Oph revealed

      We present the first reliable determination of the orbital period of the recurrent nova V2487 Oph (Nova Oph 1998). We derived a value of 0.753 ± 0.016 d (18.1 ± 0.4 h) from the radial velocity curve of the intense He II λ4686 emission line as detected in time-series X-shooter spectra. The orbital period is significantly shorter than earlier claims

      Rodríguez-Gil, Pablo et al.

      Advertised on:

      12
      2023
      Citations
      0
    • The orbital period, black hole mass, and distance to the X-ray transient GRS 1716-249 ( =N Oph 93)

      We present evidence for a 0.278(8) d ( =6.7 h) orbital period in the X-ray transient GRS 1716-249 (=N Oph 93), based on a superhump modulation detected during the 1995 mini-outburst plus ellipsoidal variability in quiescence. With a quiescent magnitude of r = 23.19 ± 0.15 N Oph 93 is too faint to warrant a full dynamical study through dedicated

      Casares, J. et al.

      Advertised on:

      12
      2023
      Citations
      1
    • UltraCompCAT: A comprehensive catalogue of ultra-compact and short orbital period X-ray binaries

      Ultracompact X-ray binaries (UCXBs) are a distinctive but elusive family of low-mass X-ray binaries (LMXBs) characterised by their tight orbits and degenerate donor stars. Here we present UltraCompCAT, the first online and comprehensive catalogue of UCXBs. The initial version of UltraCompCAT comprises 49 sources, including 20 confirmed UCXBs (those

      Armas Padilla, M. et al.

      Advertised on:

      9
      2023
      Citations
      5
    • Matter ejections behind the highs and lows of the transitional millisecond pulsar PSR J1023+0038

      Transitional millisecond pulsars are an emerging class of sources that link low-mass X-ray binaries to millisecond radio pulsars in binary systems. These pulsars alternate between a radio pulsar state and an active low-luminosity X-ray disc state. During the active state, these sources exhibit two distinct emission modes (high and low) that

      Baglio, M. C. et al.

      Advertised on:

      9
      2023
      Citations
      1
    • Sub-second infrared variability from the archetypal accreting neutron star 4U 1728-34

      We report on the first simultaneous high-time resolution X-ray and infrared (IR) observations of a neutron star low mass X-ray binary in its hard state. We performed $\approx 2\,$ h of simultaneous observations of 4U 1728-34 using HAWK-I@VLT, XMM-Newton, and NuSTAR. The source displayed significant X-ray and IR variability down to sub-second time

      Vincentelli, F. M. et al.

      Advertised on:

      10
      2023
      Citations
      1
    • A 5.3-min-period pulsing white dwarf in a binary detected from radio to X-rays

      White dwarf stars are the most common stellar fossils. When in binaries, they make up the dominant form of compact object binary within the Galaxy and can offer insight into different aspects of binary formation and evolution. One of the most remarkable white dwarf binary systems identified to date is AR Scorpii (AR Sco). AR Sco is composed of an M

      Pelisoli, Ingrid et al.

      Advertised on:

      8
      2023
      Citations
      7
    • An eclipsing 47 min double white dwarf binary at 400 pc

      We present the discovery of the eclipsing double white dwarf (WD) binary WDJ 022558.21-692025.38 that has an orbital period of 47.19 min. Following identification with the Transiting Exoplanet Survey Satellite, we obtained time series ground based spectroscopy and high-speed multiband ULTRACAM photometry which indicate a primary DA WD of mass $0.40

      Munday, James et al.

      Advertised on:

      10
      2023
      Citations
      0
    • Dynamical mass of the white dwarf in XY Ari: a test for intermediate polar X-ray spectral models

      We present a dynamical study of the eclipsing intermediate polar XY Ari based on time-resolved near-infrared spectroscopy obtained with the EMIR spectrograph on the 10.4-m Gran Telescopio Canarias. Using main sequence template spectra taken with the same instrument setup as the target spectra, we measure a radial velocity amplitude of the late K-

      Álvarez-Hernández, A. et al.

      Advertised on:

      9
      2023
      Citations
      2
    • Panning for gold, but finding helium: Discovery of the ultra-stripped supernova SN 2019wxt from gravitational-wave follow-up observations

      We present the results from multi-wavelength observations of a transient discovered during an intensive follow-up campaign of S191213g, a gravitational wave (GW) event reported by the LIGO-Virgo Collaboration as a possible binary neutron star merger in a low latency search. This search yielded SN 2019wxt, a young transient in a galaxy whose sky

      Agudo, I. et al.

      Advertised on:

      7
      2023
      Citations
      4
    • Ask the machine: systematic detection of wind-type outflows in low-mass X-ray binaries

      The systematic discovery of outflows in the optical spectra of low-mass X-ray binaries opened a new avenue for the study of the outburst evolution in these extreme systems. However, the efficient detection of such features in a continuously growing data base requires the development of new analysis techniques with a particular focus on scalability

      Mata Sánchez, D. et al.

      Advertised on:

      9
      2023
      Citations
      2
    • GRB 201015A and the nature of low-luminosity soft gamma-ray bursts

      GRB 201015A is a peculiarly low luminosity, spectrally soft gamma-ray burst (GRB), with T90 = 9.8 ± 3.5 s (time interval of detection of 90 per cent of photons from the GRB), and an associated supernova (likely to be type Ic or Ic-BL). GRB 201015A has an isotropic energy $E_{\gamma , \rm iso}$$= 1.75 ^{+0.60} _{-0.53} \times 10^{50}$ erg, and

      Patel, M. et al.

      Advertised on:

      8
      2023
      Citations
      1
    • The evolution of the UV/optical lag spectrum of NGC 7469 seen by the Liverpool Telescope

      We present the results regarding the analysis of an intensive monitoring of the Active Galactic Nucleus (AGN) NGC 7469. We observed the source for 4 months with almost daily cadence in the ugriz bands, using the IO:O on the Liverpool Telescope. We measured the lags with respect to the u band and found a clear change in the lag spectrum between the

      Vincentelli, F. M. et al.

      Advertised on:

      5
      2023
      Citations
      0
    • Optical and near-infrared spectroscopy of the black hole transient 4U 1543-47 during its 2021 ultra-luminous state

      We present simultaneous optical and near-infrared spectra obtained during the 2021 outburst of the black hole transient 4U 1543-47. The X-ray hardness-intensity diagram and the comparison with similar systems reveal a luminous outburst, probably reaching the Eddington luminosity, as well as a long-lasting excursion to the so-called ultra-luminous

      Sánchez-Sierras, J. et al.

      Advertised on:

      5
      2023
      Citations
      4
    • The Fast X-Ray Transient XRT 210423 and Its Host Galaxy

      Fast X-ray Transients (FXTs) are X-ray flares with durations ranging from a few hundred seconds to a few hours. Possible origins include the tidal disruption of a white dwarf by an intermediate-mass black hole, a supernova shock breakout, or a binary neutron star merger. We present the X-ray light curve and spectrum as well as deep optical imaging

      Eappachen, D. et al.

      Advertised on:

      5
      2023
      Citations
      3
    • Multiwavelength observations of the extraordinary accretion event AT2021lwx

      We present observations from X-ray to mid-infrared wavelengths of the most energetic non-quasar transient ever observed, AT2021lwx. Our data show a single optical brightening by a factor >100 to a luminosity of 7 × 1045 erg s-1 and a total radiated energy of 1.5 × 1053 erg, both greater than any known optical transient. The decline is smooth and

      Wiseman, P. et al.

      Advertised on:

      7
      2023
      Citations
      4
    • Neutron star mass estimates from gamma-ray eclipses in spider millisecond pulsar binaries

      Reliable neutron star mass measurements are key to determining the equation of state of cold nuclear matter, but such measurements are rare. Black widows and redbacks are compact binaries consisting of millisecond pulsars and semi-degenerate companion stars. Spectroscopy of the optically bright companions can determine their radial velocities

      Clark, C. J. et al.

      Advertised on:

      4
      2023
      Citations
      8

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