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 X-ray Emission Characteristics of Pulsars

2000 ◽  
Vol 195 ◽  
pp. 49-60
Author(s):  
W. Becker
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Emission Characteristics ◽  
Millisecond Pulsars ◽  
X Ray ◽  
Emission Properties ◽  
Important Progress

Recent X-ray observatories such as ROSAT, ASCA, RXTE, BeppoSAX, and Chandra have achieved important progress in neutron star and pulsar astronomy. The identification of Geminga as a rotation-powered pulsar, the discovery of X-ray emission from millisecond pulsars, and the identification of cooling neutron stars are only a few of the fascinating results. In the following, I will give a brief review on the X-ray emission properties of rotation-powered pulsars and their wind nebulae.

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 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 Searches for Young Pulsars

2004 ◽  
Vol 218 ◽  
pp. 97-104 ◽  
Author(s):  
Fernando Camilo
Keyword(s):  
Neutron Stars ◽  
Compact Objects ◽  
Pulsar Wind Nebulae ◽  
X Ray ◽  
Γ Ray ◽  
Pulsar Wind ◽  
Central Compact Objects

I review the results of radio and X-ray searches for pulsations from young neutron stars, emphasizing work accomplished in the last five years. I cover undirected searches, as well as directed searches of pulsar wind nebulae, EGRET γ-ray sources, and also the search for pulsations from “isolated neutron stars” and “central compact objects”.

X-ray emission characteristics of pulsars and their nebulae

2000 ◽  
Vol 177 ◽  
pp. 321-326
Author(s):  
Werner Becker
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Emission Characteristics ◽  
Millisecond Pulsars ◽  
X Ray ◽  
Emission Properties ◽  
Important Progress

AbstractRecent X-ray observatories like ROSAT, ASCA, RXTE, BeppoSAX and Chandra have achieved important progress in neutron star and pulsar astronomy. The identification of Geminga as a rotation-powered pulsar, the discovery of X-ray emission from millisecond pulsars and the identification of cooling neutron stars are only few of the fascinating results. In the following I will give a brief review on the X-ray emission properties of rotation-powered pulsars and their wind nebulae.

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.

scholarly journals Strengthening the bounds on the r-mode amplitude with X-ray observations of millisecond pulsars

2020 ◽  
Vol 498 (2) ◽  
pp. 2734-2749
Author(s):  
Tuğba Boztepe ◽  
Ersin Göğüş ◽  
Tolga Güver ◽  
Kai Schwenzer
Keyword(s):  
Neutron Star ◽  
Surface Temperature ◽  
Neutron Stars ◽  
Low Temperatures ◽  
Instability Region ◽  
Millisecond Pulsars ◽  
X Ray ◽  
Mode Amplitude ◽  
Rotation Rates ◽  
Significant Potential

ABSTRACT R-mode oscillations have been shown to have a significant potential to constrain the composition of fast spinning neutron stars. Due to their high rotation rates, millisecond pulsars (MSPs) provide a unique platform to constrain the properties of such oscillations, if their surface temperatures can be inferred. We present the results of our investigations of archival X-ray data of a number of MSPs, as well as recent XMM–Newton observations of PSR J1810+1744 and PSR J2241−5236. Using the neutron star atmosphere model and taking into account various uncertainties, we present new bounds on the surface temperature of these sources. Thereby, we significantly strengthen previous bounds on the amplitude of the r-mode oscillations in MSPs and find rigorous values as low as α ≲ 3 × 10−9. This is by now about three orders of magnitude below what standard saturation mechanisms in neutron stars could provide, which requires very strong dissipation in the interior, strongly pointing towards a structurally complex or exotic composition of these sources. At such low temperatures, sources could even be outside of the instability region, and taking into account the various uncertainties, we obtain for an observed surface temperature a simple frequency bound below which r-modes are excluded in slower spinning pulsars.

scholarly journals Imprints of Neutron Stars in the Interstellar Medium

2004 ◽  
Vol 218 ◽  
pp. 277-278 ◽  
Author(s):  
Estela M. Reynoso ◽  
Simon Johnston ◽  
Anne J. Green ◽  
W. M. Goss ◽  
Gloria M. Dubner ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Neutron Stars ◽  
Supernova Remnants ◽  
Compact Objects ◽  
X Ray ◽  
Central Compact Objects

We have carried out an H I survey towards X-ray central compact objects (CCOs) inside supernova remnants (SNRs), which shows that many of them are placed within local H I minimA. The nature of these minima is not clear, but the most likely explanation is that the CCOs have evacuated the neighboring gas. This survey also allowed us to detect a weak, diffuse radio nebula inside the SNR G266.2−1.2, probably created by the winds of its associated CCO.

scholarly journals The Neutron Star Zoo

2017 ◽  
Vol 13 (S337) ◽  
pp. 3-8
Author(s):  
Victoria M. Kaspi
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Physical Theory ◽  
Compact Objects ◽  
Grand Unification ◽  
X Rays ◽  
Radio Pulsars ◽  
Γ Rays ◽  
Central Compact Objects

AbstractSince their discovery 50 years ago, neutron stars have continually astonished. From the first-discovered radio pulsars to the powerful “magnetars” that emit sudden bursts of X-rays and γ-rays, from the so-called Isolated Neutron Stars to Central Compact Objects, observational manifestations of neutron stars are surprisingly varied, with most properties totally unpredicted. The challenge is to cement an overarching physical theory of neutron stars and their birth properties that can explain this great diversity. Here I briefly survey the disparate neutron star classes, describe their properties, highlight recent results, and describe efforts at “grand unification” of this wealth of observational phenomena.

scholarly journals Relativistic rotating vector model for X-ray millisecond pulsars

2020 ◽  
Vol 641 ◽  
pp. A166
Author(s):  
Juri Poutanen
Keyword(s):  
Neutron Star ◽  
Rotation Angle ◽  
Vector Model ◽  
Emission Region ◽  
Pulse Profile ◽  
Phase Dependence ◽  
Millisecond Pulsars ◽  
X Ray ◽  
Neutron Star Mass ◽  
Neutron Star Radius

The X-ray radiation produced on the surface of accreting magnetised neutron stars is expected to be strongly polarised. A swing of the polarisation vector with the pulsar phase gives a direct measure of the source inclination and magnetic obliquity. In the case of rapidly rotating millisecond pulsars, the relativistic motion of the emission region causes additional rotation of the polarisation plane. Here, we develop a relativistic rotating vector model, where we derive analytical expression for the polarisation angle as a function of the pulsar phase accounting for relativistic aberration and gravitational light bending in the Schwarzschild metric. We show that in the case of fast pulsars the rotation of the polarisation plane can reach tens of degrees, strongly influencing the observed shape of the polarisation angle’s phase dependence. The rotation angle grows nearly linearly with the spin rate but it is less sensitive to the neutron star radius. Overall, this angle is large even for large spots. Our results have implications with regard to the modelling of X-ray polarisation from accreting millisecond pulsars that are to be observed with the upcoming Imaging X-ray Polarimeter Explorer and the enhanced X-ray Timing and Polarimetry mission. The X-ray polarisation may improve constraints on the neutron star mass and radius coming from the pulse profile modelling.

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