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

    • Expanding the Ultracompacts: Gravitational-wave-driven Mass Transfer in the Shortest-period Binaries with Accretion Disks
      We report the discovery of three ultracompact binary white dwarf systems hosting accretion disks, with orbital periods of 7.95, 8.68, and 13.15 minutes. This significantly augments the population of mass-transferring binaries at the shortest periods, and provides the first evidence that accretors in ultracompacts can be dense enough to host
      Chakraborty, Joheen et al.

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      12
      2024
      Citations
      2
    • Fragments of harmony amid apparent chaos: A closer look at the X-ray quasi-periodic eruptions of the galaxy RX J1301.9+2747
      Quasi-periodic eruptions (QPEs) are an extreme X-ray variability phenomenon associated with low-mass (M BH < 10 7 M ⊙) supermassive black holes (SMBHs). First discovered in the nucleus of the galaxy GSN 069, they have been so far securely detected in five other galaxies, including RX J1301.9+2747. When detected, the out-of-QPE emission (quiescence)
      Giustini, Margherita et al.

      Advertised on:

      12
      2024
      Citations
      5
    • COBIPULSE: A Systematic Search for Compact Binary Millisecond Pulsars
      We report here the results obtained from a systematic optical photometric survey aimed at finding new compact binary millisecond pulsars (also known as "spiders"): the COmpact BInary PULsar SEarch. We acquired multiband optical images over 1 yr around 33 unidentified Fermi Large Area Telescope sources, selected as pulsar candidates based on their
      Turchetta, Marco et al.

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      12
      2024
      Citations
      0
    • X-ray Observations of the Very-Faint X-ray Transient XMMSL1 J171900.4-353217: A New Candidate Neutron Star Low-Mass X-ray Binary
      XMMSL1 J171900.4–353217 is a very-faint X-ray transient that was discovered in 2010 March when it exhibited an outburst. We report on 7 observations, obtained with the X-Ray Telescope (XRT) aboard the Neil Gehrels Swift Observatory between 2010 May and October. By fitting a single absorbed power-law model to the XRT spectra, we infer power-law
      Ahmed, O. et al.

      Advertised on:

      10
      2024
      Citations
      0
    • X-ray and optical observations of the millisecond pulsar binary PSR J1431–4715
      We present the first X-ray observation of the energetic millisecond pulsar binary PSR J1431‑4715, performed with XMM-Newton and complemented with fast optical multi-band photometry acquired with the ULTRACAM instrument at ESO-NTT. It is found as a faint X-ray source without a significant orbital modulation. This contrasts with the majority of
      de Martino, D. et al.

      Advertised on:

      11
      2024
      Citations
      3
    • High-quality Extragalactic Legacy-field Monitoring (HELM) with DECam: Project Overview and First Data Release
      High-quality Extragalactic Legacy-field Monitoring (HELM) is a long-term observing program that photometrically monitors several well-studied extragalactic legacy fields with the Dark Energy Camera (DECam) imager on the CTIO 4 m Blanco telescope. Since 2019 February, HELM has been monitoring regions within COSMOS, XMM-LSS, CDF-S, S-CVZ, ELAIS-S1
      Zucker, Catherine et al.

      Advertised on:

      10
      2024
      Citations
      1
    • Fast X-ray/IR observations of the black hole transient Swift J1753.5–0127: From an IR lead to a very long jet lag
      We report two epochs of simultaneous near-infrared (IR) and X-ray observations of the low-mass X-ray binary black hole candidate Swift J1753.5–0127 with a subsecond time resolution during its long 2005–2016 outburst. Data were collected strictly simultaneously with VLT/ISAAC (K S band, 2.2 μm) and RXTE (2–15 keV) or XMM-Newton (0.7–10 keV). A clear
      Malzac, J. et al.

      Advertised on:

      10
      2024
      Citations
      0
    • Short-term variability of the transitional pulsar candidate CXOU J110926.4‑650224 from X-rays to infrared
      CXOU J110926.4‑650224 is a candidate transitional millisecond pulsar (tMSP) with X-ray and radio emission properties reminiscent of those observed in confirmed tMSPs in their X-ray 'subluminous' disc state. We present the results of observing campaigns that, for the first time, characterise the optical and near-infrared variability of this source
      Coti Zelati, F. et al.

      Advertised on:

      10
      2024
      Citations
      0
    • The mass of the white dwarf in YY Dra (=DO Dra): Dynamical measurement and comparative study with X-ray estimates
      We present a dynamical study of the intermediate polar cataclysmic variable YY Dra based on time-series observations in the K band, where the donor star is known to be the major flux contributor. We covered the 3.97-h orbital cycle with 44 spectra taken between 2020 and 2022 and two epochs of photometry observed in 2021 March and May. One of the
      Álvarez-Hernández, A. et al.

      Advertised on:

      10
      2024
      Citations
      0
    • The Orbit and Companion of PSR J1622-0315: Variable Asymmetry and a Massive Neutron Star
      The companion to PSR J1622-0315, one of the most compact known redback millisecond pulsars, shows extremely low irradiation despite its short orbital period. We model this system to determine the binary parameters, combining optical observations from the New Technology Telescope in 2017 and the Nordic Optical Telescope in 2022 with the binary
      Sen, Bidisha et al.

      Advertised on:

      10
      2024
      Citations
      3
    • Kilonova Seekers: the GOTO project for real-time citizen science in time-domain astrophysics
      Time-domain astrophysics continues to grow rapidly, with the inception of new surveys drastically increasing data volumes. Democratized, distributed approaches to training sets for machine learning classifiers are crucial to make the most of this torrent of discovery - with citizen science approaches proving effective at meeting these requirements
      Killestein, T. L. et al.

      Advertised on:

      9
      2024
      Citations
      0
    • First light simultaneous triple-channel optical observations of the OPTICAM system at the OAN-SPM
      OPTICAM is a triple-band optical system developed for the 2.1 m telescope of the National Astronomical Observatory in the Sierra de San Pedro Mártir (OAN-SPM). Partial engineering tests were conducted in 2019, with the complete system experiencing its first light in March 2022. The system incorporates two beam splitters, enabling simultaneous
      Castro, Angel et al.

      Advertised on:

      11
      2024
      Citations
      0
    • Recovery of the X-ray polarisation of Swift J1727.8−1613 after the soft-to-hard spectral transition
      We report on the detection of X-ray polarisation in the black-hole X-ray binary Swift J1727.8−1613 during its dim hard spectral state by the Imaging X-ray Polarimetry Explorer (IXPE). This is the first detection of X-ray polarisation at the transition from the soft to the hard state in an X-ray binary. We find an averaged 2-8 keV polarisation
      Podgorný, J. et al.

      Advertised on:

      6
      2024
      Citations
      7
    • Optical properties of Y dwarfs observed with the Gran Telescopio Canarias
      Aims: Our science goals are to characterise the optical properties of Y dwarfs and to study their consistency with theoretical models. Methods: A sample of five Y dwarfs was observed with three optical and near-infrared instruments at the 10.4m Gran Telescopio Canarias. Deep near-infrared (J- or H-band) and multicolour optical images (z-, i-, r-, G
      Martín, E. L. et al.

      Advertised on:

      6
      2024
      Citations
      1
    • An arcsecond view at 1-2 GHz into the Galactic Bulge
      We present the results of a high angular resolution (1.1 arcsec) and sensitivity (maximum of ~0.1 mJy) radio survey at 1-2 GHz in the Galactic Bulge. This complements the X-ray Chandra Galactic Bulge Survey, and investigates the full radio source population in this dense Galactic region. Radio counterparts to sources at other wavelengths can aid in
      Pattie, E. C. et al.

      Advertised on:

      6
      2024
      Citations
      0
    • Dramatic Drop in the X-Ray Polarization of Swift J1727.8–1613 in the Soft Spectral State
      Black hole X-ray binaries exhibit different spectral and timing properties in different accretion states. The X-ray outburst of a recently discovered and extraordinarily bright source, Swift J1727.8–1613, has enabled the first investigation of how the X-ray polarization properties of a source evolve with spectral state. The 2–8 keV polarization
      Svoboda, Jiří et al.

      Advertised on:

      5
      2024
      Citations
      16
    • The double low-mass white dwarf eclipsing binary system J2102-4145 and its possible evolution
      In recent years, about 150 low-mass white dwarfs (WDs), typically with masses below 0.4 M ⊙, have been discovered. The majority of these low-mass WDs are observed in binary systems as they cannot be formed through single-star evolution within Hubble time. In this work, we present a comprehensive analysis of the double low-mass WD eclipsing binary
      Antunes Amaral, L. et al.

      Advertised on:

      5
      2024
      Citations
      1
    • Soft-state optical spectroscopy of the black hole MAXI J1305-704
      The X-ray dipper MAXI J1305-704 is a dynamically confirmed black hole (BH) X-ray binary discovered a decade ago. While its only outburst has been studied in detail in X-rays, follow-up at other wavelengths has been scarce. We report here the results from an optical spectroscopy campaign across the outburst of MAXI J1305-704. We analysed two epochs
      Miceli, C. et al.

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      4
      2024
      Citations
      1
    • PSR J0210+5845: Ultra-wide binary pulsar with a B6 V main sequence star companion
      We report on radio timing observations of PSR J0210+5845 that reveal large deviations from typical pulsar spin-down behaviour. We interpret these deviations as being due to the binary motion around the V = 13.5 star 2MASS J02105640+5845176, which is coincident in terms of its celestial position and distance with the pulsar. Archival observations
      van der Wateren, E. et al.

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      2
      2024
      Citations
      5
    • Mass estimates from optical modelling of the new TRAPUM redback PSR J1910-5320
      Spider pulsars continue to provide promising candidates for neutron star mass measurements. Here we present the discovery of PSR J1910-5320, a new millisecond pulsar discovered in a MeerKAT observation of an unidentified Fermi-LAT gamma-ray source. This pulsar is coincident with a recently identified candidate redback binary, independently
      Dodge, O. G. et al.

      Advertised on:

      3
      2024
      Citations
      6

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