scholarly journals Very young neutron stars and millisecond pulsars: the role of the accretion

2012 ◽  
Vol 8 (S290) ◽  
pp. 231-232
Author(s):  
Alexander F. Kholtygin ◽  
Andrei P. Igoshev
Keyword(s):  
Magnetic Fields ◽  
Neutron Stars ◽  
Binary Systems ◽  
Compact Objects ◽  
Millisecond Pulsars ◽  
Know How ◽  
Central Compact Objects ◽  
Low Magnetic Field ◽  
Age Determinations

AbstractWe consider the evolution of the very young neutron stars (NS) with moderate and low magnetic field values around 1E8 G to know how large is the share of the these objects among the those attributed as the millisecond pulsars (MSP). To exclude the contamination of accreted NS and young NS with moderate magnetic fields we study the observational evidences of the accretion on NS in the binary systems and different methods of age determinations. It was concluded that only central compact objects are appropriate candidates for NSs with small initial magnetic fields.

scholarly journals Central compact objects and their magnetic fields

2012 ◽  
Vol 8 (S291) ◽  
pp. 101-106 ◽  
Author(s):  
Wynn C. G. Ho
Keyword(s):  
Magnetic Fields ◽  
Neutron Stars ◽  
Supernova Remnants ◽  
Compact Objects ◽  
Spectral Measurements ◽  
X Ray ◽  
Surface Field ◽  
Weak Surface ◽  
Central Compact Objects ◽  
Weak Fields

AbstractCentral compact objects (CCOs) are neutron stars that are found near the center of supernova remnants, and their association with supernova remnants indicates these neutron stars are young (≲ 104 yr). Here we review the observational properties of CCOs and discuss implications, especially their inferred magnetic fields. X-ray timing and spectral measurements suggest CCOs have relatively weak surface magnetic fields (~ 1010 − 1011 G). We argue that, rather than being created with intrinsically weak fields, CCOs are born with strong fields and we are only seeing a weak surface field that is transitory and evolving. This could imply that CCOs are one manifestation in a unified picture of neutron stars.

scholarly journals Searching for X-ray Pulsations from Neutron Stars Using NICER

2017 ◽  
Vol 13 (S337) ◽  
pp. 187-190 ◽  
Author(s):  
Paul S. Ray ◽  
Zaven Arzoumanian ◽  
Keith C. Gendreau ◽  
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Compact Objects ◽  
Large Area ◽  
Pulse Profile ◽  
Millisecond Pulsars ◽  
X Ray ◽  
Event Time ◽  
Time Stamps ◽  
Central Compact Objects

AbstractThe Neutron Star Interior Composition Explorer (NICER) presents an exciting new capability for exploring the modulation properties of X-ray emitting neutron stars, including large area, low background, extremely precise absolute event time stamps, superb low-energy response and flexible scheduling. The Pulsation Searches and Multiwavelength Coordination working group has designed a 2.5 Ms observing program to search for emission and characterize the modulation properties of about 30 known or suspected neutron star sources across a number of source categories. A key early goal will be to search for pulsations from millisecond pulsars that might exhibit thermal pulsations from the surface suitable for pulse profile modeling to constrain the neutron star equation of state. In addition, we will search for pulsations from transitional millisecond pulsars, isolated neutron stars, low-mass X-ray binaries (LMXBs), accretion-powered millisecond pulsars, central compact objects and other sources. We present our science plan and initial results from the first months of the NICER mission, including the discovery of pulsations from the millisecond pulsar J1231–1411.

scholarly journals Central Compact Objects in Kes 79 and RCW 103 as ‘Hidden’ Magnetars with Crustal Activity

2015 ◽  
Vol 32 ◽  
Author(s):  
S. B. Popov ◽  
A. A. Kaurov ◽  
A. D. Kaminker
Keyword(s):  
Magnetic Fields ◽  
Neutron Stars ◽  
Time Scale ◽  
Compact Objects ◽  
High State ◽  
2D Modelling ◽  
Variable Activity ◽  
Error Bars ◽  
Central Compact Objects

AbstractWe propose that observations of ‘hidden’ magnetars in central compact objects can be used to probe crustal activity of neutron stars with large internal magnetic fields. Estimates based on calculations by Perna & Pons, Pons & Rea and Kaminker et al. suggest that central compact objects, which are proposed to be ‘hidden’ magnetars, must demonstrate flux variations on the time scale of months–years. However, the most prominent candidate for the ‘hidden’ magnetars — CXO J1852.6+0040 in Kes 79 — shows constant (within error bars) flux. This can be interpreted by lower variable crustal activity than in typical magnetars. Alternatively, CXO J1852.6+0040 can be in a high state of variable activity during the whole period of observations. Then we consider the source 1E161348 − 5055 in RCW103 as another candidate. Employing a simple 2D-modelling we argue that properties of the source can be explained by the crustal activity of the magnetar type. Thus, this object may be supplemented for the three known candidates for the ‘hidden’ magnetars among central compact objects discussed in literature.

scholarly journals Deriving fundamental parameters of millisecond pulsars via AIC in white dwarfs

2012 ◽  
Vol 8 (S290) ◽  
pp. 177-178
Author(s):  
A. Taani ◽  
C. M. Zhang ◽  
Y. H. Zhao ◽  
A. Moraghan
Keyword(s):  
Magnetic Fields ◽  
Neutron Stars ◽  
White Dwarfs ◽  
Binary Systems ◽  
Millisecond Pulsars ◽  
Fundamental Parameters ◽  
Evolutionary Connection ◽  
Binary Evolution

AbstractWe present a study of the observational properties of Millisecond Pulsars (MSPs) by way of their magnetic fields, spin periods and masses. These measurements are derived through the scenario of Accretion Induced Collapse (AIC) of white dwarfs (WDs) in stellar binary systems, in order to provide a greater understanding of the characteristics of MSP populations. In addition, we demonstrate a strong evolutionary connection between neutron stars and WDs with binary companions from a stellar binary evolution perspective via the AIC process.

scholarly journals Evolution of Neutron Star Magnetic Fields

Universe ◽  
2021 ◽  
Vol 7 (9) ◽  
pp. 351
Author(s):  
Andrei P. Igoshev ◽  
Sergei B. Popov ◽  
Rainer Hollerbach
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Magnetic Fields ◽  
Neutron Stars ◽  
Binary Systems ◽  
Theoretical Models ◽  
Compact Objects ◽  
Open Problems ◽  
Origin And Evolution ◽  
Field Decay

Neutron stars are natural physical laboratories allowing us to study a plethora of phenomena in extreme conditions. In particular, these compact objects can have very strong magnetic fields with non-trivial origin and evolution. In many respects, its magnetic field determines the appearance of a neutron star. Thus, understanding the field properties is important for the interpretation of observational data. Complementing this, observations of diverse kinds of neutron stars enable us to probe parameters of electro-dynamical processes at scales unavailable in terrestrial laboratories. In this review, we first briefly describe theoretical models of the formation and evolution of the magnetic field of neutron stars, paying special attention to field decay processes. Then, we present important observational results related to the field properties of different types of compact objects: magnetars, cooling neutron stars, radio pulsars, and sources in binary systems. After that, we discuss which observations can shed light on the obscure characteristics of neutron star magnetic fields and their behaviour. We end the review with a subjective list of open problems.

scholarly journals Spin Evolution of the Progenitors of Binary and Millisecond Pulsars

1996 ◽  
Vol 165 ◽  
pp. 57-64
Author(s):  
Pranab Ghosh
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Binary System ◽  
Neutron Stars ◽  
High Magnetic Field ◽  
Evolutionary History ◽  
Millisecond Pulsars ◽  
History Of ◽  
Low Magnetic Field ◽  
Fast Rotating

In this symposium, I have been given the task of summarizing our current understanding of the evolutionary history of spin periods of the neutron stars that we now see as binary and millisecond pulsars, i.e., recycled pulsars. We believe that a newborn, fast-spinning neutron star (with a rather high magnetic field ∼1011–1013 G) in a binary system first operates as a spin-powered pulsar, subsequently as an accretion-powered pulsar when accretion begins after the pulsar has been spun down adequately, and finally as a spin-powered pulsar for the second time after having been recycled to become a very fast-rotating neutron star (with a rather low magnetic field ∼108–1011 G) (see Ghosh 1994a, b, hereafter G94a, b).

scholarly journals Accretion onto Relativistic Objects

1974 ◽  
Vol 64 ◽  
pp. 194-212
Author(s):  
M. J. Rees
Keyword(s):  
Black Holes ◽  
Interstellar Medium ◽  
Neutron Stars ◽  
Binary Systems ◽  
Compact Object ◽  
Stellar Mass ◽  
Supermassive Black Holes ◽  
Compact Objects ◽  
X Ray ◽  
Intergalactic Space

The physics of spherically symmetrical accretion onto a compact object is briefly reviewed. Neither neutron stars nor stellar-mass black holes are likely to be readily detectable if they are isolated and accreting from the interstellar medium. Supermassive black holes in intergalactic space may however be detectable. The effects of accretion onto compact objects in binary systems are then discussed, with reference to the phenomena observed in variable X-ray sources.

scholarly journals Late Stages of the Evolution of Close Binaries

1984 ◽  
Vol 80 ◽  
pp. 335-354
Author(s):  
C. De Loore ◽  
W. Sutantyo
Keyword(s):  
Mass Transfer ◽  
Neutron Stars ◽  
Binary Systems ◽  
Exceptional Case ◽  
Compact Objects ◽  
Close Binaries ◽  
Millisecond Pulsar ◽  
X Ray ◽  
Compact Component ◽  
X Ray Binaries

AbstractClose binaries can evolve through various ways of interaction into compact objects (white dwarfs, neutron stars, black holes). Massive binary systems (mass of the primary M1 larger than 14 to 15 M0) are expected to leave, after the first stage of mass transfer a compact component orbiting a massive star. These systems evolve during subsequent stages into massive X-ray binaries. Systems with initial large periode evolve into Be X-ray binaries.Low mass X-ray sources are probably descendants of lower mass stars, and various channels for their production are indicated. The evolution of massive close binaries is examined in detail and different X-ray stages are discussed. It is argued that a first X-ray stage is followed by a reverse extensive mass transfer, leading to systems like SS433, CirXl. During further evolution these systems would become Wolf-Rayet runaways. Due to spiral in these system would then further evolve into ultra short X-ray binaries like CygX-3.Finally the explosion of the secondary will in most cases disrupt the system. In an exceptional case the system remains bound, leading to binary pulsars like PSR 1913 +16. In such systems the orbit will shrink due to gravitational radiation and finally the two neutron stars will coalesce. It is argued that the millisecond pulsar PSR 1937 + 214 could be formed in this way.A complete scheme starting from two massive ZAMS stars, ending with a millisecond pulsar is presented.

scholarly journals Off-equatorial circular orbits in magnetic fields of compact objects

2008 ◽  
Vol 4 (S259) ◽  
pp. 125-126 ◽  
Author(s):  
Zdeněk Stuchlík ◽  
Jiří Kovář ◽  
Vladimír Karas
Keyword(s):  
Black Holes ◽  
Magnetic Fields ◽  
Neutron Stars ◽  
Compact Objects ◽  
Circular Orbits ◽  
Naked Singularities ◽  
Plasma Ring

AbstractWe present results of investigation of the off-equatorial circular orbits existence in the vicinity of neutron stars, Schwarzschild black holes with plasma ring, and near Kerr-Newman black holes and naked singularities.

scholarly journals Radiation from rapidly rotating oblate neutron stars

2018 ◽  
Vol 615 ◽  
pp. A50 ◽  
Author(s):  
J. Nättilä ◽  
P. Pihajoki
Keyword(s):  
Neutron Stars ◽  
Spectral Energy Distribution ◽  
Numerical Algorithms ◽  
Second Order ◽  
Compact Objects ◽  
Spectral Energy ◽  
Full Width ◽  
Millisecond Pulsars ◽  
Frame Dragging ◽  
Jacobi Formalism

A theoretical framework for emission originating from rapidly rotating oblate compact objects is described in detail. Using a Hamilton-Jacobi formalism, we show that special relativistic rotational effects such as aberration of angles, Doppler boosting, and time dilatation naturally emerge from the general relativistic treatment of rotating compact objects. We use the Butterworth–Ipser metric expanded up to the second order in rotation and hence include effects of light bending, frame-dragging, and quadrupole deviations on our geodesic calculations. We also give detailed descriptions of the numerical algorithms used and provide an open-source implementation of the numerical framework called BENDER. As an application, we study spectral line profiles (i.e., smearing kernels) from rapidly rotating oblate neutron stars. We find that in this metric description, the second-order quadrupole effects are not strong enough to produce narrow observable features in the spectral energy distribution for almost any physically realistic parameter combination, and hence, actually detecting them is unlikely. The full width at tenth-maximum and full width at half-maximum of the rotation smearing kernels are also reported for all viewing angles. These can then be used to quantitatively estimate the effects of rotational smearing on the observed spectra. We also calculate accurate pulse profiles and observer skymaps of emission from hot spots on rapidly rotating accreting millisecond pulsars. These allow us to quantify the strength of the pulse fractions one expects to observe from typical fast-spinning millisecond pulsars.

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