E.P.J. van den Heuvel

Formation and evolution of binary and millisecond radio pulsars

Abstract We review the various ways in which binary pulsars, millisecond pulsars and pulsars in globular clusters may have formed. To this end the formation processes of neutron stars in interacting binaries, and the subsequent evolution of such systems are discussed. In section 2 the observed properties of radio pulsars, single as well as in binaries, are briefly reviewed. The peculiar combination of rapid spin and relatively weak magnetic fields of the binary and millisecond pulsars and the high incidence of binaries among millisecond pulsars strongly suggest that many of them (if not all) are old neutron stars that have been “recycled” by the accretion of mass and angular momentum from a companion star in a mass-transfer binary. Recycled pulsars are expected to represent a later evolutionary phase of various observed types of binary X-ray sources. In section 3 the observed properties of the various types of binary X-ray sources are summarized, and the evolutionary history of close binary systems leading to the formation of X-ray binaries is reviewed. In view of the relevance for the later evolution of X-ray binaries into binary and millisecond pulsars, we discuss in this section also the effect of various types of accretion (from a stellar wind, and by Roche-lobe overflow) on the spin evolution of accreting magnetized neutron stars. Subsequently the later evolution and final evolutionary products of X-ray binaries are discussed. Massive X-ray binaries may in the end either leave (i) a very close binary pulsar consisting of two neutron stars (with an eccentric orbit) or a neutron star and a massive white dwarf with a circular orbit, or (ii) two runaway pulsars, one newborn and one recycled, or (iii) a single low-velocity recycled pulsar. Low-mass X-ray binaries may either leave relatively wide binaries with circular orbits consisting of a low-mass (0.2–0.4M⊙) white dwarf and a recycled neutron star, or a single recycled neutron star which has “evaporated” its companion star, or possibly has merged with it. We also discuss in this section the possible origin of the velocity-magnetic field correlation observed in single radio pulsars. The correlation can be obtained by a combination of close binary evolution and the occurrence of asymmetries in supernova mass ejection or, alternatively, by a combination of close binary evolution and the evaporation of low-mass companions to young pulsars. Section 4 is devoted to the special formation and evolution processes of close neutron star binaries that operate in globular star clusters. The high incidence of pulsars (mostly binary and/or millisecond pulsars) in globular clusters and the origin of the relatively large fraction (≳ 50%) of single pulsars among them is discussed. From the discussions in section 4 and section 5 it is concluded that so far no clear evidence - nor the need - for the formation of neutron stars (millisecond pulsars) by the accretion-induced collapse of white dwarfs in globular clusters has been presented, although this formation mechanism cannot be excluded. For the formation of low-mass X-ray binaries in the galactic disk this mechanism, however, may make a significant contribution. In section 5 the statistical properties of the binary and millisecond pulsars in globular clusters and in the general field are discussed in relation to the evolution of neutron star magnetic fields. The following conclusions are drawn: 1. (i) There is no longer clear evidence that the magnetic fields of isolated neutron stars (radio pulsars) do decay. 2. (ii) Neutron stars that have been recycled by accretion in close binaries do show clear evidence for magnetic field decay. This field decay may be due to either (a) the accretion process itself or (b) the spin evolution of the neutron stars in binaries which has affected the magnetic field carried by the liquid interior of the neutron star. 3. (iii) A sizeable fraction of all observed single radio pulsars (of order several tens of per cent) may have been recycled in (mostly massive) close binaries. The presence of this group in the general pulsar population may have created the impression that the magnetic fields of single neutron stars do decay. In section 6 the findings of earlier sections are summarized and some open problems are listed.

Common envelope evolution: where we stand and how we can move forward

This work aims to present our current best physical understanding of common-envelope evolution (CEE). We highlight areas of consensus and disagreement, and stress ideas which should point the way forward for progress in this important but long-standing and largely unconquered problem. Unusually for CEE-related work, we mostly try to avoid relying on results from population synthesis or observations, in order to avoid potentially being misled by previous misunderstandings. As far as possible we debate all the relevant issues starting from physics alone, all the way from the evolution of the binary system immediately before CEE begins to the processes which might occur just after the ejection of the envelope. In particular, we include extensive discussion about the energy sources and sinks operating in CEE, and hence examine the foundations of the standard energy formalism. Special attention is also given to comparing the results of hydrodynamic simulations from different groups and to discussing the potential effect of initial conditions on the differences in the outcomes. We compare current numerical techniques for the problem of CEE and also whether more appropriate tools could and should be produced (including new formulations of computational hydrodynamics, and attempts to include 3D processes within 1D codes). Finally we explore new ways to link CEE with observations. We compare previous simulations of CEE to the recent outburst from V1309 Sco, and discuss to what extent post-common-envelope binaries and nebulae can provide information, e.g. from binary eccentricities, which is not currently being fully exploited.

Catalogue of high-mass X-ray binaries in the Galaxy (4th edition)

We present a new edition of the catalogue of high-mass X-ray binaries in the Galaxy. The catalogue contains source name(s), coordinates, finding chart, X-ray luminosity, system parameters, and stellar parameters of the components and other characteristic properties of 114 high-mass X-ray binaries, together with a comprehensive selection of the relevant literature. The aim of this catalogue is to provide the reader with some basic information on the X-ray sources and their counterparts in other wavelength ranges (gamma-rays, UV, optical, IR, radio). About 60% of the high-mass X-ray binary candidates are known or suspected Be/X-ray binaries, while 32% are supergiant/X-ray binaries. Some sources, however, are only tentatively identified as high-mass X-ray binaries on the basis of their X-ray properties similar to the known high-mass X-ray binaries. Further identification in other wavelength bands is needed to finally determine the nature of these sources. In cases where there is some doubt about the high-mass nature of the X-ray binary this is mentioned. Literature published before 1 October 2005 has, as far as possible, been taken into account.

A catalogue of low-mass X-ray binaries in the Galaxy, LMC, and SMC (Fourth edition)

We present a new edition of the catalogue of the low-mass X-ray binaries in the Galaxy and the Magellanic Clouds. The catalogue contains source name(s), coordinates, finding chart, X-ray luminosity, system parameters, and stellar parameters of the components and other characteristic properties of 187 low-mass X-ray binaries, together with a comprehensive selection of the relevant literature. The aim of this catalogue is to provide the reader with some basic information on the X-ray sources and their counterparts in other wavelength ranges (gamma-rays, UV, optical, IR, and radio). Some sources, however, are only tentatively identified as low-mass X-ray binaries on the basis of their X-ray properties similar to the known low-mass X-ray binaries. Further identification in other wavelength bands is needed to finally determine the nature of these sources. In cases where there is some doubt about the low-mass nature of the X-ray binary this is mentioned. Literature published before 1 October 2006 has, as far as possible, been taken into account.

The host of GRB 030323 at z=3.372: A very high column density DLA system with a low metallicity

We present photometry and spectroscopy of the afterglow of GRB 030323. VLT spectra of the afterglow show damped Lyα (DLA) absorption and low- and high-ionization lines at a redshift z = 3.3718 ± 0.0005. The inferred neutral hy- drogen column density, log N(Hi) = 21.90 ± 0.07, is larger than any (GRB- or QSO-) DLA H  column density inferred directly from Lyα in absorption. From the afterglow photometry, we derive a conservative upper limit to the host-galaxy extinction: AV < 0.5 mag. The iron abundance is (Fe/H) = −1.47 ± 0.11, while the metallicity of the gas as measured from sulphur is (S/H) = −1.26 ± 0.20. We derive an upper limit on the H2 molecular fraction of 2N(H2)/(2N(H2) + N(Hi)) < 10 −6 .I n the Lyα trough, a Lyα emission line is detected, which corresponds to a star-formation rate (not corrected for dust extinction) of roughly 1 Myr −1 . All these results are consistent with the host galaxy of GRB 030323 consisting of a low metallicity gas with a low dust content. We detect fine-structure lines of silicon, Si *, which have never been clearly detected in QSO-DLAs; this suggests that these lines are produced in the vicinity of the GRB explosion site. Under the assumption that these fine-structure levels are populated by particle collisions, we estimate the H  volume density to be nHi = 10 2 −10 4 cm −3 .H ST/ACS imaging 4 months after the burst shows an extended AB(F606W) = 28.0 ± 0.3 mag object at a distance of 0.

Is SAX J1808.4-3658 a strange star?

The possibility of strange stars is one of the most important issues in the study of compact objects. Here we use the observations of the newly discovered millisecond x-ray pulsar SAX J1808.4-3658 to constrain the radius of the compact star. Comparing the mass-radius relation of SAX J1808.4-3658 with theoretical models for both neutron stars and strange stars, we argue that a strange star model could be more consistent with SAX J1808.4-3658, and suggest that it is a likely strange star candidate. Our results are useful in constraining microscopic chiral symmetry restoration parameters in the quantum chromodynamics (QCD) modeling of strange matter.

Formation and evolution of compact stellar X-ray sources

In this chapter we review the formation and evolution of compact binaries with neutron star and/or black hole components (i.e. LMXBs, HMXBs, binary pulsars). After an introduction we discuss stellar evolution in binaries and the processes involved in the mass-transfer phases of close binaries (RLO, CE, ang.mom.loss) with radiative/convective hydrogen or helium donor stars. We also describe the effects of accretion, asymmetric SN and systems merging as a result of gravitational wave radiation.

The Neutron Star-Black Hole Connection

Preface. List of Participants. 1: Radio Pulsars and Neutron Stars. Radio Pulsars - an Observers Perspective D.R. Lorimer. Neutron Star Birth Rates D.R. Lorimer. Kinematics of Radio Pulsars R. Ramachandran. Superfluid Dynamics and Energy Dissipation in Neutron Stars M.A. Alpar. Magnetic Fields of Neutron Stars S. Konar, D. Bhattacharya. 2: The Neutron Star - Black Hole Connection. Neutron Star and Black Hole Formation C.L. Fryer. Coalescence Rates of Compact Objects V. Kalogera. The Final Fate of Coalescing Compact Binaries: From Black Hole to Planet Formation F.A. Rasio. 3: Accretion Discs. Accretion Discs H.C. Spruit. Radiatively Inefficient Accretion Discs H.C. Spruit. Inner Region of Accretion Flows onto Black Holes M. Kafatos, P. Subramanian. 4: Neutron stars and Black Holes in Binaries. Neutron Stars and Black Holes in Binaries E.P.J. van den Heuvel. Formation and Evolution of Neutron Stars and Black Holes in Binary Systems E.P.J. van den Heuvel. Transient Low-Mass X-Ray Binaries in Quiescence L. Bildsten, R.E. Rutledge. A Comparison of Radio Emission from Neutron Star and Black Hole X-ray Binaries R.P. Fender. Black Hole and Neutron Star Jet Sources I.F. Mirabel. Bulk-Flow Comptonization and Time Lags due to Comptonization N.D. Kylafis, P. Reig. GRS 1915+105 as a Black Hole Accretion Disk Laboratory T. Belloni. Weighing Black Holes with the Largest Optical Telescopes E.T. Harlaftis, A.V. Filippenko. Physics of Plasma Outflows S.V. Bogovalov, K. Tsinganos. Timing the Kilohertz Quasi-periodic Oscillations in Low-Mass Binaries M. Mendez. Modeling the Time Variability of Black Hole Candidates D.Kazanas. Relativistic Models of kHz QPOs W. Kluzniak. Phenomenology of the 35-day Cycle of Hercules X-1 N.I. Shakura, et al. Spin-Orbit Couplings in X-ray Binaries T.M. Tauris, G.J. Savonije. High Mass Black Holes in Soft X-ray Transients G.E. Brown, et al. 5: Magnetars. The Anomalous X-ray Pulsars S. Mereghetti. Astrophysics of the Soft Gamma Repeaters and the Anomalous X-ray Pulsars C. Thompson. Neutron Star Envelopes and Thermal Radiation from the Magnetic Surface J. Ventura, and A.Y. Potekhin. 6: Gamma-ray Bursts. Gamma-ray Bursts: History and Observations G.J. Fishman. The Afterglow of Gamma-ray Bursts: Light on the Mystery L. Piro. Gamma-ray Bursts and Afterglows: The Fireball Shock Model P. Meszaros. Gamma-ray Bursts from Neutron Stars Spun up in X-ray Binaries H.C. Spruit. 7: New Experiments. The Candra X-ray Observatory (CXO) M.C. Weisskopf.

Very high column density and small reddening toward GRB 020124 at z = 3.20

We present optical and near-infrared observations of the dim afterglow of GRB 020124, obtained between 2 and 68 hr after the gamma-ray burst. The burst occurred in a very faint (R 29.5) damped Lyα absorber (DLA) at a redshift of z = 3.198 ± 0.004. The derived column density of neutral hydrogen is log(N) = 21.7 ± 0.2, and the rest-frame reddening is constrained to be E(B-V) < 0.065, i.e., AV < 0.20 for standard extinction laws with RV ≈ 3. The resulting dust-to-gas ratio is less than 11% of that found in the Milky Way but consistent with the SMC and high-redshift QSO DLAs, indicating a low metallicity and/or a low dust-to-metal ratio in the burst environment. A gray extinction law (large RV), produced through preferential destruction of small dust grains by the gamma-ray burst, could increase the derived AV and dust-to-gas ratio. The dimness of the afterglow is, however, fully accounted for by the high redshift: if GRB 020124 had been at z = 1, it would have been approximately 1.8 mag brighter—in the range of typical bright afterglows.

On the evolution and fate of super-massive stars

Context. We study the evolution and fate of solar composition super-massive stars in the mass range 60–1000 M� . Our study is relevant for very massive objects observed in young stellar complexes as well as for super-massive stars that could potentially form through runaway stellar collisions. Aims. We predict the outcomes of stellar evolution by employing a mass-loss prescription that is consistent with the observed Hertzsprung-Russell Diagram location of the most massive stars. Methods. We compute a series of stellar models with an appropriately modified version of the Eggleton evolutionary code. ,