Magnetar

About: Magnetar is a research topic. Over the lifetime, 2905 publications have been published within this topic receiving 106806 citations.

The Proper Motion of PSR J1550-5418 Measured with VLBI: A Second Magnetar Velocity Measurement

Abstract: The formation mechanism of neutron stars with extremely large magnetic field strengths (magnetars) remains unclear. Some formation scenarios predict that magnetars should be born with extremely high space velocities, >1000 km s–1. Using the Long Baseline Array in Australia, we have measured the proper motion of the intermittently radio-bright magnetar PSR J1550-5418 (1E 1547.0-5408): μ = 9.2 ± 0.6 mas yr–1. For a likely distance of 6 ± 2 kpc, the implied transverse velocity is 280+130 – 120 km s–1 after correcting for Galactic rotation. Along with the ≈200 km s–1 transverse velocity measured for the magnetar XTE J1810-197, this result suggests that formation pathways producing large magnetic fields do not require very large birth kicks.

Constraining the Type of Central Engine of GRBs with Swift Data

Abstract: The central engine of gamma-ray bursts (GRBs) is poorly constrained. There exist two main candidates: a fast-rotating black hole and a rapidly spinning magnetar. Furthermore, the X-ray plateaus are widely accepted by the energy injection into the external shock. In this paper, we systematically analyze the \emph{Swift}/XRT light curves of 101 GRBs having plateau phases and known redshifts (before May 2017). Since a maximum energy budget ($\sim2\times10^{52}$ erg) exists for magnetars but not for a black hole, this provides a good clue to identify the type of GRB central engine. We calculate the isotropic kinetic energy $E_{\rm K,iso}$ and the isotropic X-ray energy release $E_{\rm X,iso}$ for individual GRB. We identify three categories based on how likely a black hole harbor at central engine: 'Gold' (9 out of 101, both $E_{\rm X,iso}$ and $E_{\rm K,iso}$ exceed the energy budget), 'Silver' (69 out of 101, $E_{\rm X,iso}$ less than the limit but $E_{\rm K,iso}$ is greater than the limit), and 'Bronze' (23 out of 101, the energies are not above the limit). We then derive and test the black hole parameters with the Blandford Znajek mechanism, and find that the observations of the black hole candidate ('Gold'+'Silver') samples are consistent with the expectations of the black hole model. Furthermore, we also test the magnetar candidate ('Bronze') sample with the magnetar model, and find that the magnetar surface magnetic led ($B_{p}$) and initial spin period ($P_{0}$) are consistent with the expectations of the magnetar model. Our analysis indicates that, if the magnetar wind is isotropic, a magnetar central engine is possible for 20\% of the analyzed GRBs. For most GRBs a black hole is most likely operating.

The nature of unidentified galactic high-energy gamma-ray sources

Abstract: Preface. Participants to the Workshop. Part I: Unidentified Gamma-Ray Sources. 1. Unidentified Gamma-Ray Sources: an Introduction D.J. Thompson. 2. Gamma-Ray Properties of Unidentified EGRET Sources O. Reimer. 3. Multiwavelength Searches and Spectral Aspects of 3EG Sources R. Mukherjee, J. Halpern. Part II: Correlations. 4. Gamma-Ray Sources off the Galactic Plane I.A. Grenier. 5. Low-Latitude Gamma-Ray Sources G.E. Romero. 6. Population Studies of Unidentified gamma-Ray Sources N. Gehrels, et al. 7. Population Studies of the EGRET Sources S. Mereghetti, et al.Gap' Perspective R.W. Romani. 12. Polar Cap Pulsar Models M.G. Baring. Part IV: Supernova Remnants and Massive Stars. 13. Massive Stars and Gamma-Ray Sources P. Kaaret. 14. Diffuse Sources of High-Energy Gamma Rays in the Milky Way S.W. Digel. 15. Shock Acceleration and Photon Production in Supernova Remnants D.C. Ellison. 16. X-Ray Studies of Supernova Remnants P. Slane. Part V: Galactic Microquasars, Binaries and Black Holes. 17. Micrcoquasars in the Galaxy L.F. Rodriquez, I.F. Mirabel. 18. VLT Observations of Galactic Microquasars J. Marti, et al. 19. The Case of LS 5039 J.M. Paredes, et al. 20. Non-Pulsating Black Holes as High Energy Gamma-Ray Sources B. Punsly. Part VI: Identification and Perspectives. 21. TeV Observations of Supernova Remnants and Unidentified Sources S. Fegan.22. A First EGRET-UNID-Related Agenda for Cherenkov Telescopes D. Petry. 23. g-Ray Astronomy in the Era of GLAST N. Gehrels. 24. The AGILE Gamma-Ray Astronomy Satellite S. Mereghetti, et al. 25. Multiwavelength Round-Table Presentations D. Petry, et al. Part VII: Summary. 26. Unidentified Gamma-Ray Sources: Summary and Conclusion D.J. Thompson. Topic Index. Author Index.

Crystalline chiral condensates as a component of compact stars

Abstract: We investigate the influence of spatially inhomogeneous chiral symmetry-breaking condensates in a magnetic field background on the equation of state for compact stellar objects. After building a hybrid star composed of nuclear and quark matter using the Maxwell construction, we find, by solving the Tolman-Oppenheimer-Volkoff equations for stellar equilibrium, that our equation of state supports stars with masses around $2{M}_{\ensuremath{\bigodot}}$ for values of the magnetic field that are in accordance with those inferred from magnetar data. The inclusion of a weak vector interaction term in the quark part allows one to reach two solar masses for relatively small central magnetic fields, making this composition a viable possibility for describing the internal degrees of freedom of this class of astrophysical objects.

An Energetic Magnetar in HESS J1713-381/CTB 37B

Abstract: We obtained a second Chandra timing measurement of the 3.82 s pulsar CXOU J171405.7-381031 in the supernova remnant (SNR) CTB 37B, which shows that it is spinning down rapidly. The average period derivative of (5.88+/-0.08)E-11 over the 1 year time span corresponds to a dipole magnetic field strength B = 4.8E14 G, well into the magnetar range. The spin-down power E-dot = 4.2E34 erg/s is among the largest for magnetars, and the corresponding characteristic age Tau = P/2P-dot = 1030 years is comparable to estimates of the age of the SNR. The period derivative enables us to recover probable pulsations in an ASCA observation taken in 1996, which yields a mean characteristic age of 860 years over the longer 13 year time span. The source is well detected up to 10 keV, and its composite spectrum is typical of a magnetar. CTB 37B hosts HESS J1713-381, the first TeV source that is coincident with a magnetar. While the TeV emission has been attributed to the SNR shell, it is possibly centrally peaked, and we hypothesize that this particularly young, energetic magnetar may contribute to the HESS source. We also searched for pulsations from another source in a HESS SNR, XMMU J173203.3-344518 in HESS J1731-347/G353.6-0.7 but could not confirm pulsations or long-term flux variability, making it more likely that this source is a weakly magnetized central compact object.