Related papers: Young rotation-powered pulsars as ultra-luminous X…
We have completed part of a program to study the X-ray emission properties of old rotation-powered pulsars with XMM-Newton in order to probe and identify the origin of their X-radiation. The X-ray emission from these old pulsars is largely…
The accreting compact objects in most of ultraluminous X-ray sources (ULXs) are likely to be neutron stars rather than black holes as suggested by the recent detection of periodic pulsations from some of these sources located in neighboring…
With the discovery of pulsations in some of the ultra-luminous X-ray sources (ULXs), it is quite clear that most of the ULXs harbor either a neutron star or a stellar mass black hole as a compact object accreting at super-Eddington rates.…
The appearance of subsonic propellers situated in a strong wind is discussed. We show that it is similar to the appearance of anomalous X-ray pulsars (AXPs) provided the mass and the magnetic moment of neutron stars are 1.4 solar masses,…
We explore the effect of pulsars, in particular those born with millisecond periods, on their surrounding supernova ejectas. While they spin down, fast-spinning pulsars release their tremendous rotational energy in the form of a…
We compare the rotation rate of neutron stars in low-mass X-ray binaries (LMXBs) with the orbital period of the binaries. We find that, while short orbital period LMXBs span a range of neutron star rotation rates, all the long period LMXBs…
Ultra-luminous X-ray sources (ULXs) are a class of extra-galactic, point-like, off-nuclear X-ray sources with X-ray luminosity from $\sim 10^{39}$~erg s$^{-1}$ to $10^{41}$~erg s$^{-1}$. We investigated the temporal and broadband X-ray…
We have used XMM-Newton's Optical Monitor (OM) images to study the local environment of a sample of 27 Ultraluminous X-ray Sources (ULXs) in nearby galaxies. UVW1 fluxes were extracted from 100 pc regions centered on the ULX positions. We…
Discovery of pulsations from a number of ULXs proved that accretion onto neutron stars can produce luminosities exceeding the Eddington limit by several orders of magnitude. The conditions necessary to achieve such high luminosities as well…
We consider the three currently known pulsing ultraluminous X--ray sources (PULXs). We show that in one of them the observed spinup rate requires super--Eddington accretion rates at the magnetospheric radius, even if magnetar--strength…
Luminosities and uxes of the expected population of galactic gamma-ray pulsars become foreseeable if physical distributions at birth and evolutive history are assigned. In this work we estimate the contribution of pulsar uxes to the…
Rotation-powered millisecond radio pulsars have been spun up to their present spin period by a $10^8$ - $10^9$ yr long X-ray-bright phase of accretion of matter and angular momentum in a low-to-intermediate mass binary system. Recently, the…
We analyze all X-ray timing data on 1E 1207.4-5209 in supernova remnant PKS 1209-51/52 gathered in 2000-2005, and find a highly stable rotation with P=424.130451(4) ms and period derivative of (9.6 +/- 9.4)E-17 s/s. This refutes previous…
NGC 300 ULX1 is the fourth to be discovered in the class of the ultra-luminous X-ray pulsars. Pulsations from NGC 300 ULX1 were discovered during simultaneous XMM-Newton / NuSTAR observations in Dec. 2016. The period decreased from 31.71 s…
A scenario of the formation of isolated X-ray pulsars is discussed with an application to one of the best studied objects of this class 1E 161348-5055. This moderately luminous, 10^33 - 10^35 erg/s, pulsar with a relatively soft spectrum,…
The Anomalous X-ray Pulsars (AXPs) are a small class of pulsars with spin periods in the 6-12 s range, very soft X-ray spectra, secular spin down on time scales of ~10^3-10^5 years, and lack of bright optical counterparts. Two, possibly…
Assuming a naive star formation history, we construct the synthetic X-ray source populations for comparison with the X-ray luminosity function (XLF) of the interacting galaxies NGC 4038/4039 using a population synthesis code. We have…
We report on NuSTAR observations of transient pulsations in the neutron star X-ray binary SMC X-1. The transition from non-pulsing to pulsing states was not accompanied by a large change in flux. Instead, both pulsing and non-pulsing states…
Ultraluminous X-ray sources (ULX) are extragalactic objects with X-ray luminosities above the Eddington limit for a 10 Msun black hole (BH). ULXs may host super-Eddington accreting neutron stars or stellar mass BH, although the exact…
The pulsations of X-ray pulsars carry information about the accretion and magnetic field geometry. Here we present a study and classification of energy resolved pulse profiles of a sample of X-ray pulsars, focusing on high-mass X-ray…