SEARCHING FOR COMPACT OBJECTS IN SUPERNOVA REMNANTS: INITIAL RESULTS

Compact Stars ◽  
2004 ◽  
Author(s):  
D. L. KAPLAN ◽  
S. R. KULKARNI ◽  
D. A. FRAIL ◽  
B. M. GAENSLER ◽  
P. O. SLANE ◽  
...  
Keyword(s):  
Supernova Remnants ◽  
Compact Objects ◽  
Initial Results

scholarly journals Searching for Compact Objects in Supernova Remnants: Initial Results

2004 ◽  
Vol 218 ◽  
pp. 123-126
Author(s):  
D. L. Kaplan ◽  
S. R. Kulkarni ◽  
D. A. Frail ◽  
B. M. Gaensler ◽  
P. O. Slane ◽  
...  
Keyword(s):  
Black Holes ◽  
Neutron Stars ◽  
Supernova Remnants ◽  
Compact Objects ◽  
Cooling Curves ◽  
Limited Sample ◽  
Central Source ◽  
Systematic Effort ◽  
Cas A ◽  
Initial Results

Most astronomers now accept that stars more massive than about 9 M⊙ explode as supernovae and leave stellar remnants, either neutron stars or black holes. However, less than half of the SNRs within 5 kpc have identified central sources. Here, we discuss a systematic effort to search for compact central sources in the remaining 23 SNRs of this distance-limited sample. As the first part of this survey, we are able to state with some confidence that there are no associated central sources down to a level of one tenth of that of the Cas A central source, LX ≲ 1031 ergs s−1, in four SNRs (G093.3+6.9, G315.4−2.3, G084.2+0.8, and G127.1+0.5). We compare our limits with cooling curves for neutron stars and find that any putative neutron stars in these SNRs must be cooling faster than expected for traditional 1.35 M⊙ neutron stars.

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 Progenitors and explosion properties of supernova remnants hosting central compact objects: I. RCW 103 associated with the peculiar source 1E 161348−5055

2019 ◽  
Vol 489 (3) ◽  
pp. 4444-4463 ◽  
Author(s):  
C Braun ◽  
S Safi-Harb ◽  
C L Fryer
Keyword(s):  
Supernova Remnants ◽  
Model Fitting ◽  
Plasma Temperature ◽  
Compact Object ◽  
Compact Objects ◽  
Explosion Energy ◽  
Uniform Medium ◽  
Order Of Magnitude ◽  
Central Compact Objects ◽  
Collisional Ionization

ABSTRACT We present a Chandra and XMM–Newton imaging and spectroscopic study of the supernova remnant (SNR) RCW 103 (G332.4−00.4) containing the central compact object 1E 161348−5055. The high-resolution Chandra X-ray images reveal enhanced emission in the south-eastern and north-western regions. Equivalent width line images of Fe L, Mg, Si, and S using XMM–Newton data were used to map the distribution of ejecta. The SNR was sectioned into 56 regions best characterized by two-component thermal models. The harder component (kT ∼ 0.6 keV) is adequately fitted by the VPSHOCK non-equilibrium ionization model with an ionization time-scale net ∼ 1011–1012 cm−3 s, and slightly enhanced abundances over solar values. The soft component (kT ∼ 0.2 keV), fitted by the APEC model, is well described by plasma in collisional ionization equilibrium with abundances consistent with solar values. Assuming a distance of 3.1 kpc and a Sedov phase of expansion into a uniform medium, we estimate an SNR age of 4.4 kyr, a swept-up mass Msw = 16$f_\mathrm{ s}^{-1/2}$ D$_{3.1}^{5/2}$ M⊙, and a low explosion energy E* = 3.7 × 1049 $f_\mathrm{ s}^{-1/2}$ D$_{3.1}^{5/2}$ erg. This energy could be an order of magnitude higher if we relax the Sedov assumption, the plasma has a low filling factor, the plasma temperature is underestimated, or if the SNR is expanding into the progenitor’s wind-blown bubble. Standard explosion models did not match the ejecta yields. By comparing the fitted abundances to the most recent core-collapse nucleosynthesis models, our best estimate yields a low-mass progenitor of around 12–13 M⊙, lower than previously reported. We discuss degeneracies in the model fitting, particularly the effect of altering the explosion energy on the progenitor mass estimate.

scholarly journals Powering central compact objects with a tangled crustal magnetic field

2020 ◽  
Vol 495 (2) ◽  
pp. 1692-1699 ◽  
Author(s):  
Konstantinos N Gourgouliatos ◽  
Rainer Hollerbach ◽  
Andrei P Igoshev
Keyword(s):  
Magnetic Field ◽  
Supernova Remnants ◽  
Initial Conditions ◽  
Supernova Explosion ◽  
Compact Objects ◽  
Dipole Field ◽  
Ohmic Dissipation ◽  
X Ray ◽  
Axisymmetric Structure ◽  
Central Compact Objects

ABSTRACT Central Compact Objects (CCOs) are X-ray sources with luminosity ranging between 1032 and 1034 erg s−1, located at the centres of supernova remnants. Some of them have been confirmed to be neutron stars. Timing observations have allowed the estimation of their dipole magnetic field, placing them in the range ∼1010–1011 G. The decay of their weak dipole fields, mediated by the Hall effect and Ohmic dissipation, cannot provide sufficient thermal energy to power their X-ray luminosity, as opposed to magnetars whose X-ray luminosities are comparable. Motivated by the question of producing high X-ray power through magnetic field decay while maintaining a weak dipole field, we explore the evolution of a crustal magnetic field that does not consist of an ordered axisymmetric structure, but rather comprises a tangled configuration. This can be the outcome of a non-self-excited dynamo, buried inside the crust by fallback material following the supernova explosion. We find that such initial conditions lead to the emergence of the magnetic field from the surface of the star and the formation of a dipolar magnetic field component. An internal tangled magnetic field of the order of 1014 G can provide sufficient Ohmic heating to the crust and power CCOs, while the dipole field it forms is approximately 1010 G, as observed in CCOs.

scholarly journals What causes the absence of pulsations in Central Compact Objects in supernova remnants?

2021 ◽  
Vol 21 (11) ◽  
pp. 294
Author(s):  
Qi Wu ◽  
Adriana M. Pires ◽  
Axel Schwope ◽  
Guang-Cheng Xiao ◽  
Shu-Ping Yan ◽  
...  
Keyword(s):  
Neutron Stars ◽  
Supernova Remnants ◽  
Compact Objects ◽  
Evolutionary Path ◽  
Spectral Components ◽  
Periodic Signals ◽  
The Common ◽  
Central Compact Objects ◽  
Star Surface ◽  
Homogeneous Temperature

Abstract Most young neutron stars belonging to the class of Central Compact Objects (CCOs) in supernova remnants do not have known periodicities. We investigated seven such CCOs to understand the common reasons for the absence of detected pulsations. Making use of XMM-Newton, Chandra, and NICER observations, we perform a systematic timing and spectral analysis to derive updated sensitivity limits for both periodic signals and multi-temperature spectral components that could be associated with radiation from hotspots on the neutron star surface. Based on these limits, we then investigated for each target the allowed viewing geometry that could explain the lack of pulsations. We find that it is unlikely (< 10−6) to attribute that we do not see pulsations to an unfavorable viewing geometry for five considered sources. Alternatively, the carbon atmosphere model, which assumes homogeneous temperature distribution on the surface, describes the spectra equally well and provides a reasonable interpretation for the absence of detected periodicities within current limits. The unusual properties of CCOs with respect to other young neutron stars could suggest a different evolutionary path, as that proposed for sources experiencing episodes of significant fallback accretion after the supernova event.

scholarly journals Resolving dichotomy in compact objects through continuous gravitational waves observation

2021 ◽  
Vol 508 (1) ◽  
pp. 842-851
Author(s):  
Surajit Kalita ◽  
Tushar Mondal ◽  
Christopher A Tout ◽  
Tomasz Bulik ◽  
Banibrata Mukhopadhyay
Keyword(s):  
Magnetic Field ◽  
Gravitational Wave ◽  
Supernova Remnants ◽  
Laser Interferometer ◽  
Gamma Ray ◽  
Signal To Noise Ratio ◽  
Big Bang ◽  
Compact Objects ◽  
One Year ◽  
The Masses

ABSTRACT More than two dozen soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) have been detected so far. These are isolated compact objects. Many of them are either found to be associated with supernova remnants or their surface magnetic fields are directly measured, confirming that they are neutron stars (NSs). However, it has been argued that some SGRs and AXPs are highly magnetized white dwarfs (WDs). Meanwhile, the existence of super-Chandrasekhar WDs has remained to be a puzzle. However, not even a single such massive WD has been observed directly. Moreover, some WD pulsars are detected in electromagnetic surveys and some of their masses are still not confirmed. Here, we calculate the signal-to-noise ratio for all these objects, considering different magnetic field configurations and thereby estimate the required time for their detection by various gravitational wave (GW) detectors. For SGRs and AXPs, we show that, if these are NSs, they can hardly be detected by any of the GW detectors, while if they are WDs, big bang Observer (BBO), DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) and Advanced Laser Interferometer Antenna (ALIA) would be able to detect them within a few days to a year of integration, depending on the magnetic field strength and its configuration. Similarly, if a super-Chandrasekhar WD has a dominant toroidal field, we show that even Laser Interferometer Space Antenna (LISA) and TianQin would be able to detect it within one year of integration. We also discuss how GWs can confirm the masses of the WD pulsars.

scholarly journals Central Compact Objects in Supernova Remnants

2004 ◽  
Vol 218 ◽  
pp. 239-246 ◽  
Author(s):  
George G. Pavlov ◽  
Divas Sanwal ◽  
Marcus A. Teter
Keyword(s):  
Neutron Stars ◽  
Supernova Remnants ◽  
Compact Objects ◽  
X Ray ◽  
Central Regions ◽  
Supernova Explosions ◽  
Central Compact Objects

There are point-like sources in central regions of several supernova remnants which have not been detected outside the X-ray range. The X-ray spectra of these Central Compact Objects (CCOs) have thermal components with blackbody temperatures of 0.2–0.5 keV and characteristic sizes of 0.3-3 km. Most likely, the CCOs are neutron stars born in supernova explosions. We overview their observational properties, emphasizing the Chandra data, and compare them with magnetars.

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