Effects of magnetic field topology in black hole-neutron star mergers: Long-term simulations

ABSTRACT IGR J17091–3624 is a low-mass X-ray binary (LMXB), which received wide attention from the community thanks to its similarities with the bright black hole system GRS 1915+105. Both systems exhibit a wide range of highly structured X-ray variability during outburst, with time-scales from few seconds to tens of minutes, which make them unique in the study of mass accretion in LMXBs. In this work, we present a general overview into the long-term evolution of IGR J17091–3624, using Swift/XRT observations from the onset of the 2011–2013 outburst in 2011 February till the end of the last bright outburst in 2016 November. We found four re-flares during the decay of the 2011 outburst, but no similar re-flares appear to be present in the latter one. We studied, in detail, the period with the lowest flux observed in the last 10 yr, just at the tail end of the 2011–2013 outburst, using Chandra and XMM-Newton observations. We observed changes in flux as high as a factor of 10 during this period of relative quiescence, without strong evidence of softening in the spectra. This result suggests that the source has not been observed at its true quiescence so far. By comparing the spectral properties at low luminosities of IGR J17091–3624 and those observed for a well-studied population of LMXBs, we concluded that IGR J17091–3624 is most likely to host a black hole as a compact companion rather than a neutron star.

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CLOSE BINARY PROGENITORS OF HYPERNOVAE

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194512004618 ◽

2012 ◽

Vol 08 ◽

pp. 209-219 ◽

Cited By ~ 2

Author(s):

MAXIM V. BARKOV

Keyword(s):

Magnetic Field ◽

Black Hole ◽

Neutron Star ◽

Binary Systems ◽

Close Binary ◽

Transient Event ◽

Common Envelope ◽

Starting Point ◽

The Common ◽

Rayet Star

In this paper we propose a new plausible mechanism of supernova explosions specific to close binary systems. The starting point is the common envelope phase in the evolution of a binary consisting of a red super giant and a neutron star. As the neutron star spirals towards the center of its companion it spins up via disk accretion. Depending on the specific angular momentum of gas captured by the neutron star via the Bondi-Hoyle mechanism, it may reach millisecond periods either when it is still inside the common envelope or after it has merged with the companion core. The high accretion rate may result in strong differential rotation of the neutron star and generation of a magnetar-strength magnetic field. The magnetar wind can blow away the common envelope if its magnetic field is as strong as 1015 G, and can destroy the entire companion if it is as strong as 1016 G. The total explosion energy can be comparable to the rotational energy of a millisecond pulsar and reach 1052 erg. The result is an unusual type-II supernova with very high luminosity during the plateau phase, followed by a sharp drop in brightness and a steep light-curve tail. The remnant is either a solitary magnetar or a close binary involving a Wolf-Rayet star and a magnetar. When this Wolf-Rayet star explodes this will be a third supernovae explosion in the same binary. A particularly interesting version of the binary progenitor involves merger of a red super giant star with an ultra-compact companion, neutron star or black hole. In the case if a strong magnetic field is not generated on the surface of a neutron star then it will collapse to a black hole. After that we expect the formation of a very long-lived accretion disk around the black hole. The Blandford-Znajek driven jet from this black hole may drive not only hypernovae explosion but produce a bright X-ray transient event on a time scale of 104 s.

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Close encounters with the Death Star: Interactions between collapsed bodies and the Solar System

Astronomy and Astrophysics ◽

10.1051/0004-6361/202140454 ◽

2021 ◽

Vol 648 ◽

pp. L2 ◽

Cited By ~ 1

Author(s):

Václav Pavlík ◽

Steven N. Shore

Keyword(s):

Black Hole ◽

Neutron Star ◽

Solar System ◽

Planetary System ◽

Planetary Systems ◽

Symplectic Integrator ◽

Orbital Parameters ◽

Long Term Stability ◽

Complete Disruption

Aims. We aim to investigate the consequences of a fast massive stellar remnant – a black hole (BH) or a neutron star (NS) – encountering a planetary system. Methods. We modelled a close encounter between the actual Solar System (SS) and a 2 M⊙ NS and a 10 M⊙ BH, using a few-body symplectic integrator. We used a range of impact parameters, orbital phases at the start of the simulation derived from the current SS orbital parameters, encounter velocities, and incidence angles relative to the plane of the SS. Results. We give the distribution of possible outcomes, such as when the SS remains bound, when it suffers a partial or complete disruption, and in which cases the intruder is able to capture one or more planets, yielding planetary systems around a BH or a NS. We also show examples of the long-term stability of the captured planetary systems.

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Observations of GRO J1744–28 in quiescence with XMM-Newton

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038093 ◽

2020 ◽

Vol 643 ◽

pp. A62

Author(s):

V. Doroshenko ◽

V. Suleimanov ◽

S. Tsygankov ◽

J. Mönkkönen ◽

L. Ji ◽

...

Keyword(s):

Magnetic Field ◽

Neutron Star ◽

Binary System ◽

Galactic Center ◽

Optical Counterpart ◽

X Ray ◽

Upper Limit ◽

Dipole Term ◽

The Magnetic Field

We report on the deep observations of the “bursting pulsar” GRO J1744–28, which were performed with XMM-Newton and aimed to clarify the origin of its X-ray emission in quiescence. We detect the source at a luminosity level of ∼1034 erg s−1 with an X-ray spectrum that is consistent with the power law, blackbody, or accretion-heated neutron star atmosphere models. The improved X-ray localization of the source allowed us to confirm the previously identified candidate optical counterpart as a relatively massive G/K III star at 8 kpc close to the Galactic center, implying an almost face-on view of the binary system. Although we could only find a nonrestricting upper limit on the pulsed fraction of ∼20%, the observed hard X-ray spectrum and strong long-term variability of the X-ray flux suggest that the source is also still accreting when not in outburst. The luminosity corresponding to the onset of centrifugal inhibition of accretion is thus estimated to be at least two orders of magnitude lower than previously reported. We discuss this finding in the context of previous studies and argue that the results indicate a multipole structure in the magnetic field with the first dipole term of ∼1010 G, which is much lower than previously assumed.

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ROSAT Observations of Soft X-ray Transients in Quiescence

Symposium - International Astronomical Union ◽

10.1017/s0074180900055790 ◽

1996 ◽

Vol 165 ◽

pp. 333-339

Author(s):

Frank Verbunt

Keyword(s):

Magnetic Field ◽

Black Hole ◽

Neutron Star ◽

Neutron Stars ◽

Weak Magnetic Field ◽

Small Surface ◽

X Ray ◽

Surface Areas ◽

Actual Spectrum ◽

Small Surface Area

Four soft X-ray transients, two with a neutron star and two with a black hole, have been detected at quiescence with ROSAT. Blackbody fits to their spectra give temperatures of 160–300 eV, and surface areas of <1 km2. The small surface area suggests that the actual spectrum may be optically thin. The companion star does not contribute significantly to the X-ray luminosity, except perhaps in the case of A 0620-00. From the observation that accretion continues at luminosity levels of ∼1033 erg s−1 it is concluded that the neutron stars in Aql X-1 and Cen X-4 have a weak magnetic field and rotate rather slowly.

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Population of Short γ-ray Bursters — Result of Gravitational lensing of “Quiet” γ-ray Sources in Remote Galaxies

International Astronomical Union Colloquium ◽

10.1017/s0252921100035363 ◽

1995 ◽

Vol 151 ◽

pp. 363-366

Author(s):

G.M. Beskin

Keyword(s):

Magnetic Field ◽

Black Hole ◽

Neutron Star ◽

Gravitational Lensing ◽

Spectral Properties ◽

Brightness Distribution ◽

Source Plane ◽

Critical Curves ◽

Flux Variability ◽

Γ Ray

We consider the hypothesis of the existence of a class of short (10−2-10−3s) and weak (10−6-10−7erg/s· cm2) γ-bursts of cosmological origin. These events arise from gravitational microlensing of bright, quiet γ-ray sources (with luminosity about 3·1038erg/s) located in distant (z ≥ 1) galaxies by stars inside foreground galaxies. If the size of the γ-ray sources is 104-106cm, motion with respect to the observer or the intermediate galaxy may bring them close to the neigborhood of cusps along critical curves generated by individual stars (corresponding to caustics in the observer’s plane). In these cases the observed fluxes increase by a factor 1011-1013, the temporal variation of intensity being due to the brightness distribution in the source and to the distance from the cusp (in the source plane). Using standard assumptions for the number and sizes of “quiet” γ-ray sources, the number and characteristics of galaxies, we estimate the observed burst rate to be between 1 and 10 bursts per year (see below). Their temporal and spectral properties are determined by the nature of sources (ejecting pulsar, accreting neutron star with a weak or strong magnetic field, black hole) and by their velocity relative to the cusp. Similar effects have been discussed in the context of flux variability and structure studies of quasars (e.g. Schneider & Weiss 1986, Grieger et al. 1988, Refsdal & Surdej 1994). However, in these cases the source sizes were larger than 1014cm3 and amplification did not exceed 102.

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The Nature and Evolutionary Status of GRO J1744–28

International Astronomical Union Colloquium ◽

10.1017/s0252921100042767 ◽

1997 ◽

Vol 163 ◽

pp. 289-299

Author(s):

P. C. Joss ◽

S. Rappaport

Keyword(s):

Magnetic Field ◽

Mass Transfer ◽

Neutron Star ◽

Neutron Stars ◽

Evolutionary Status ◽

Type I ◽

Core Mass ◽

X Ray ◽

The Magnetic Field

AbstractGRO J1744–28 is the first known X-ray source to display both bursts and periodic pulsations. This source may thus provide crucial clues that will lead to an understanding of the differences in the nature of the X-ray variability among accreting neutron stars. We deduce that the magnetic field of the neutron star is relatively weak (~ 8 × 1010G) but, nevertheless, sufficiently strong to funnel the accretion flow onto the magnetic polar caps and suppress the thermonuclear flashes that would otherwise give rise to type I X-ray bursts. We also present a series of interrelated arguments which demonstrate that the observed bursts are of type II and probably result from an instability associated with the interaction of the neutron-star magnetic field with the inner edge of the accretion disk. From these results, we infer that X-ray pulsars, GRO J1744–28, the Rapid Burster, and the type I X-ray bursters may form a sequence of possible behaviors among accreting neutron stars, with the strength of the magnetic field serving as the crucial parameter that determines the mode of X-ray variability. The companion star in the GRO J1744–28 binary system is probably a very low-mass (~ 0.2M⊙) giant that is in the final stages of losing its hydrogen-rich envelope. We have carried out binary evolution calculations which show that (1) if the mass of the giant was ~ 1M⊙when mass transfer onto the neutron star commenced, then the orbital period and the core mass of the giant have increased from ~ 1 to ~ 11.8 days and from ~ 0.15 to ~ 0.21M⊙, respectively, during the mass-transfer epoch, which has lasted for ~ 8 × 108yr, (2) the present long-term average X-ray luminosity is ~ 4 × 1036ergs s−1, which is at least two orders of magnitude lower than the luminosity at the peak of the transient outburst, and (3) the predicted long-term equilibrium rotation rate of the neutron star is remarkably close to the observed pulse rate. The transient nature of GRO J1744–28 may well be related to the final stages of dissipation of the envelope of the giant companion.

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Jet launching from binary black hole-neutron star mergers: Dependence on black hole spin, binary mass ratio, and magnetic field orientation

Physical Review D ◽

10.1103/physrevd.98.123017 ◽

2018 ◽

Vol 98 (12) ◽

Cited By ~ 11

Author(s):

Milton Ruiz ◽

Stuart L. Shapiro ◽

Antonios Tsokaros

Keyword(s):

Magnetic Field ◽

Black Hole ◽

Neutron Star ◽

Mass Ratio ◽

Field Orientation ◽

Magnetic Field Orientation ◽

Black Hole Spin ◽

Binary Black Hole

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Gamma Ray Bursts as Death of Magnetized Neutron Stars

International Astronomical Union Colloquium ◽

10.1017/s0252921100041907 ◽

1996 ◽

Vol 160 ◽

pp. 361-362

Author(s):

Hitoshi Hanami

Keyword(s):

Magnetic Field ◽

Black Hole ◽

Neutron Star ◽

Neutron Stars ◽

Strong Magnetic Field ◽

Gamma Ray ◽

Gamma Ray Bursts ◽

Final Phase ◽

Poynting Flux ◽

Free Process

AbstractWe propose magnetic cannon ball mechanism in which the collapse of a magnetosphere onto a black hole can generate strong outward Poynting flux which can drive a baryon-free fireball. This process can occur at the final collapsing phase of a neutron star with strong magnetic field. The magnetic cannon ball can drive a relativistic outflow without the rotation of the central object. This baryon-free process can explain gamma-ray bursts as the final phase of dead pulsars.

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Evolution of Large-Scale Coronal Structures

International Astronomical Union Colloquium ◽

10.1017/s0252921100024945 ◽

1994 ◽

Vol 144 ◽

pp. 29-33

Author(s):

P. Ambrož

Keyword(s):

Magnetic Field ◽

Field Line ◽

Large Scale ◽

Coronal Magnetic Field ◽

Source Surface ◽

Solar Cycles ◽

Characteristic Relationship ◽

The Magnetic Field ◽

Coronal Structures

AbstractThe large-scale coronal structures observed during the sporadically visible solar eclipses were compared with the numerically extrapolated field-line structures of coronal magnetic field. A characteristic relationship between the observed structures of coronal plasma and the magnetic field line configurations was determined. The long-term evolution of large scale coronal structures inferred from photospheric magnetic observations in the course of 11- and 22-year solar cycles is described.Some known parameters, such as the source surface radius, or coronal rotation rate are discussed and actually interpreted. A relation between the large-scale photospheric magnetic field evolution and the coronal structure rearrangement is demonstrated.

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