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

    • Probing for the host galaxies of the fast X-ray transients XRT 000519 and XRT 110103
      Over the past few years, ~30 extragalactic fast X-ray transients (FXRTs) have been discovered, mainly in Chandra and XMM-Newton data. Their nature remains unclear, with proposed origins, including a double neutron star merger, a tidal disruption event involving an intermediate-mass black hole and a white dwarf, or a supernova shock breakout. A
      Eappachen, D. et al.

      Advertised on:

      7
      2022
      Citations
      9
    • Characterizing eclipsing white dwarf M dwarf binaries from multiband eclipse photometry
      With the prevalence of wide-field, time-domain photometric sky surveys, the number of eclipsing white dwarf (WD) systems being discovered is increasing dramatically. An efficient method to follow these up will be key to determining any population trends and finding any particularly interesting examples. We demonstrate that multiband eclipse
      Brown, Alex J. et al.

      Advertised on:

      6
      2022
      Citations
      7
    • A Tentative 114 minute Orbital Period Challenges the Ultracompact Nature of the X-Ray Binary 4U 1812-12
      We present a detailed time-resolved photometric study of the ultracompact X-ray binary candidate 4U 1812-12. The multicolor light curves obtained with HiPERCAM on the 10.4 m Gran Telescopio Canarias show a ≃114 minute modulation similar to a superhump. Under this interpretation, this period should lie very close to the orbital period of the system
      Armas Padilla, Montserrat et al.

      Advertised on:

      5
      2022
      Citations
      1
    • A Misfired Outburst in the Neutron Star X-Ray Binary Centaurus X-4
      We report on a long-term optical monitoring of the neutron star X-ray binary Centaurus X-4 performed during the last 13.5 yr. This source has been in quiescence since its outburst in 1979. Our monitoring reveals the overall evolution of the accretion disk; we detect short-duration flares, likely originating also in the disk, superimposed with a
      Baglio, M. C. et al.

      Advertised on:

      5
      2022
      Citations
      7
    • The Donor of the Black Hole X-Ray Binary MAXI J1820+070
      We estimate the parameters of the donor of the accreting black hole binary MAXI J1820+070. The measured values of the binary period, rotational and radial velocities, and constraints on the orbital inclination imply the donor is a subgiant with the mass of ${M}_{2}\approx {0.49}_{-0.10}^{+0.10}{M}_{\odot }$ and the radius of ${R}_{2}\approx {1.19}_
      Mikołajewska, Joanna et al.

      Advertised on:

      5
      2022
      Citations
      11
    • A 62-minute orbital period black widow binary in a wide hierarchical triple
      Over a dozen millisecond pulsars are ablating low-mass companions in close binary systems. In the original `black widow', the eight-hour orbital period eclipsing pulsar PSR J1959+2048 (PSR B1957+20) 1, high-energy emission originating from the pulsar 2 is irradiating and may eventually destroy 3 a low-mass companion. These systems are not only
      Burdge, Kevin B. et al.

      Advertised on:

      5
      2022
      Citations
      14
    • SOAR/Goodman Spectroscopic Assessment of Candidate Counterparts of the LIGO/Virgo Event GW190814
      On 2019 August 14 at 21:10:39 UTC, the LIGO/Virgo Collaboration (LVC) detected a possible neutron star-black hole merger (NSBH), the first ever identified. An extensive search for an optical counterpart of this event, designated GW190814, was undertaken using the Dark Energy Camera on the 4 m Victor M. Blanco Telescope at the Cerro Tololo Inter
      Tucker, D. L. et al.

      Advertised on:

      4
      2022
      Citations
      12
    • The SN Ia runaway LP 398-9: detection of circumstellar material and surface rotation
      A promising progenitor scenario for Type Ia supernovae (SNeIa) is the thermonuclear detonation of a white dwarf in a close binary system with another white dwarf. After the primary star explodes, the surviving donor can be spontaneously released as a hypervelocity runaway. One such runaway donor candidate is LP 398-9, whose orbital trajectory
      Chandra, Vedant et al.

      Advertised on:

      6
      2022
      Citations
      12
    • The peculiar chemical abundance of the transitional millisecond pulsar PSR J1023+0038 - Li enhancement
      Using high-resolution optical spectroscopy we determine the chemical abundance of the secondary star in the binary millisecond pulsar PSR J1023+0038. We measure a metallicity of [Fe/H] = 0.48 ± 0.04 which is higher than the Solar value and in general find that the element abundances are different compared to the secondary stars in X-ray binaries
      Shahbaz, T. et al.

      Advertised on:

      6
      2022
      Citations
      10
    • Discovery and characterization of five new eclipsing AM CVn systems
      AM CVn systems are ultra-compact, hydrogen-depleted, and helium-rich, accreting binaries with degenerate or semidegenerate donors. We report the discovery of five new eclipsing AM CVn systems with orbital periods of 61.5, 55.5, 53.3, 37.4, and 35.4 min. These systems were discovered by searching for deep eclipses in the Zwicky Transient Facility
      van Roestel, J. et al.

      Advertised on:

      6
      2022
      Citations
      32
    • Measuring the mass of the black widow PSR J1555-2908
      Accurate measurements of the masses of neutron stars are necessary to test binary evolution models, and to constrain the neutron star equation of state. In pulsar binaries with no measurable post-Keplerian parameters, this requires an accurate estimate of the binary system's inclination and the radial velocity of the companion star by other means
      Kennedy, M. R. et al.

      Advertised on:

      5
      2022
      Citations
      18
    • A persistent ultraviolet outflow from an accreting neutron star binary transient
      All disc-accreting astrophysical objects produce powerful disc winds. In compact binaries containing neutron stars or black holes, accretion often takes place during violent outbursts. The main disc wind signatures during these eruptions are blue-shifted X-ray absorption lines, which are preferentially seen in disc-dominated `soft states' 1,2. By
      Castro Segura, N. et al.

      Advertised on:

      3
      2022
      Citations
      32
    • The Gravitational-wave Optical Transient Observer (GOTO): prototype performance and prospects for transient science
      The Gravitational-wave Optical Transient Observer (GOTO) is an array of wide-field optical telescopes, designed to exploit new discoveries from the next generation of gravitational wave detectors (LIGO, Virgo, and KAGRA), study rapidly evolving transients, and exploit multimessenger opportunities arising from neutrino and very high energy gamma-ray
      Steeghs, D. et al.

      Advertised on:

      4
      2022
      Citations
      37
    • Hard-state Optical Wind during the Discovery Outburst of the Black Hole X-Ray Dipper MAXI J1803-298
      We present 12 epochs of optical spectroscopy taken across the discovery outburst of the black hole (BH) candidate MAXI J1803-298 with the Gran Telescopio Canarias and Very Large Telescope. The source followed a standard outburst evolution with hard and soft states. The system displays a triangular shape in the hardness intensity diagram, consistent
      Mata Sánchez, D. et al.

      Advertised on:

      2
      2022
      Citations
      22
    • Relentless and complex transits from a planetesimal debris disc
      This article reports quasi-continuous transiting events towards WD 1054-226 at d = 36.2 pc and V = 16.0 mag, based on simultaneous, high-cadence, multiwavelength imaging photometry using ULTRACAM over 18 nights from 2019 to 2020 March. The predominant period is 25.02 h and corresponds to a circular orbit with blackbody T eq = 323 K, where a
      Farihi, J. et al.

      Advertised on:

      4
      2022
      Citations
      22
    • MUSE spectroscopy of planetary nebulae with high abundance discrepancies
      We present MUSE deep integral-field unit spectroscopy of three planetary nebulae (PNe) with high-abundance discrepancy factors (ADF > 20): NGC 6778, M 1-42, and Hf 2-2. We have constructed flux maps for more than 40 emission lines, and use them to build extinction, electron temperature (T e), electron density (n e), and ionic abundances maps of a
      García-Rojas, J. et al.

      Advertised on:

      3
      2022
      Citations
      29
    • Searching for nova shells around cataclysmic variables - II. A second campaign
      We report on our second campaign to search for old nova shells around cataclysmic variables (CVs). Our aim was to test the theory that nova eruptions cause cycles in the mass transfer rates of CVs. These mass transfer cycles change the behaviour of CVs during their intereruption periods. We examined Hα images of 47 objects and found no new shells
      Sahman, D. I. et al.

      Advertised on:

      3
      2022
      Citations
      4
    • The return of the spin period in DW Cnc and evidence of new high state outbursts
      DW Cnc is an intermediate polar which has previously been observed in both high and low states. Observations of the high state of DW Cnc have previously revealed a spin period at ~38.6 min, however, observations from the 2018 to 2019 low state showed no evidence of the spin period. We present results from our analysis of 12 s cadence photometric
      Duffy, C. et al.

      Advertised on:

      2
      2022
      Citations
      5
    • System parameters of three short-period cataclysmic variable stars
      Using photometric ULTRACAM observations of three new short-period cataclysmic variables (CVs), we model the primary eclipse light curves to extract the orbital separation, masses, and radii of their component stars. We find donor masses of $0.060\pm 0.008\, {\rm M_\odot }$, $0.042\pm 0.001\, {\rm M_\odot }$, and $0.042\pm 0.004\, {\rm M_\odot }$
      Wild, J. F. et al.

      Advertised on:

      2
      2022
      Citations
      5
    • The Observed Mass Distribution of Galactic Black Hole LMXBs Is Biased against Massive Black Holes
      The discovery of gravitational-wave radiation from merging black holes (BHs) also uncovered BHs with masses in the range of ≍20-160 M ⊙. In contrast, the most massive Galactic stellar-mass BH currently known has a mass of ≍21 M ⊙. While low-mass X-ray binaries (LMXBs) will never independently evolve into a binary BH system, and binary evolution
      Jonker, Peter G. et al.

      Advertised on:

      11
      2021
      Citations
      34

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