We report the results of the first X-ray observation of the luminous and helium-rich O-type subdwarf BD +37° 442 carried out with the XMM-Newton satellite in 2011 August. X-ray emission is detected with a flux of about 3× 10−14 erg cm−2 s−1 (0.2–1 keV) and a very soft spectrum, well fit by the sum of a blackbody with temperature kTBB = 45+11− 9 eV, and a power law with a poorly constrained photon index. Significant pulsations with a period of 19.2 s are detected, indicating that the X-ray emission originates in a white dwarf or neutron star companion, most likely powered by accretion from the wind of BD +37° 442.

Subdwarf

Black-body radiation

10.1088/2041-8205/750/2/l34

Cite

Citations (17)

A magnetar giant flare in the nearby starburst galaxy M82

Nature (2024)

S. Mereghetti Michela Rigoselli R. Salvaterra Dominik Patryk Pacholski J. Rodi

Magnetar

Flare

Large Magellanic Cloud

10.1038/s41586-024-07285-4

Cite

Citations (12)

XMM-Newton Observations of CXOU J010043.1-721134: The First Deep Look at the Soft X-Ray Emission of a Magnetar

The Astrophysical Journal (2008)

A. Tiengo P. Esposito S. Mereghetti

We present the analysis of six XMM-Newton observations of the Anomalous X-ray Pulsar CXOU J010043.1-721134, the magnetar candidate characterized by the lowest interstellar absorption. In contrast with all the other magnetar candidates, its X-ray spectrum cannot be fit by an absorbed power-law plus blackbody model. The sum of two (absorbed) blackbody components with kT1=0.30 keV and kT2=0.7 keV gives an acceptable fit, and the radii of the corresponding blackbody emission regions are R1=12.1 km and R2=1.7 km. The former value is consistent with emission from a large fraction of a neutron star surface and, given the well known distance of CXOU J010043.1-721134, that is located in the Small Magellanic Cloud, it provides the most constraining lower limit to a magnetar radius ever obtained. A more physical model, where resonant cyclotron scattering in the magnetar magnetosphere is taken into account, has also been successfully applied to this source.

Magnetar

Black-body radiation

X-ray pulsar

10.1086/590078

Cite

Citations (37)

Quiet but still bright:XMM-Newtonobservations of the soft gamma-ray repeater SGR 0526-66

Monthly Notices of the Royal Astronomical Society Letters (2009)

A. Tiengo P. Esposito S. Mereghetti G. L. Israel L. Stella

SGR 0526-66 was the first soft gamma-ray repeater (SGR) from which a giant flare was detected in March 1979, suggesting the existence of magnetars, i.e. neutron stars powered by the decay of their extremely strong magnetic field. Since then, very little information has been obtained on this object, mainly because it has been burst-inactive since 1983 and the study of its persistent X-ray emission has been hampered by its large distance and its location in a X-ray bright supernova remnant in the Large Magellanic Cloud. Here we report on a comprehensive analysis of all the available XMM-Newton observations of SGR 0526-66. In particular, thanks to a deep observation taken in 2007, we measured its pulsation period (P = 8.0544 +/- 0.0002 s) 6 years after its latest detection by Chandra. This allowed us to detect for the first time a significant reduction of its spin-down rate. From a comparison with two shorter XMM-Newton observations performed in 2000 and 2001, we found no significant changes in the spectrum, which is well modelled by an absorbed power-law with nH = 4.6E+21 cm^-2 and photon index = 3.27. The high luminosity (about 4E+35 erg/s, in the 1-10 keV energy band) still observed about 25 years after the latest detection of bursting activity places SGR 0526-66 in the group of bright and persistent magnetar candidates.

Magnetar

Flare

Large Magellanic Cloud

10.1111/j.1745-3933.2009.00728.x

Cite

Citations (27)

The variable spin-down rate of the transient magnetar XTE J1810−197

Monthly Notices of the Royal Astronomical Society (2016)

Fabio Pintore F. Bernardini S. Mereghetti P. Esposito R. Turolla

We have analysed XMM–Newton and Chandra observations of the transient magnetar XTE J1810−197 spanning more than 11 yr, from the initial phases of the 2003 outburst to the current quiescent level. We investigated the evolution of the pulsar spin period and we found evidence for two distinct regimes: during the outburst decay, |$\dot{\nu }$| was highly variable in the range −(2−4.5) × 10−13 Hz s−1, while during quiescence the spin-down rate was more stable at an average value of −1 × 10−13 Hz s−1. Only during ∼3000 d (from MJD 54165 to MJD 56908) in the quiescent stage it was possible to find a phase-connected timing solution, with |$\dot{\nu }=-4.9\times 10^{-14}$| Hz s−1, and a positive second frequency derivative, |$\ddot{\nu }=1.8\times 10^{-22}$| Hz s−2. These results are in agreement with the behaviour expected if the outburst of XTE J1810−197 was due to a strong magnetospheric twist.

Magnetar

Transient (computer programming)

10.1093/mnras/stw351

Cite

Citations (26)

Ten years of XMM-Newton observations of RX J1856.5-3754

N. Sartore S. Mereghetti A. Tiengo A. De Luca R. Turolla

We report on the spectral analysis of all the imaging observations of the isolated neutron star RX J1856.5–3754 performed with the XMM-Newton satellite over the last decade. Adopting a single blackbody model, we found variations of the fit parameters of ∼ 1% between different observations, which correlate with the position of the source on the detector and thus are indicative of an instrumental origin. Focusing on a sub-sample of observations, with the source in the same position on the detector, the temperature is compatible with a constant during the period from March 2005 to the present date. A high quality spectrum obtained from this sub-sample is best-fitted with a sum of two blackbodies, with temperatures of kT∞ h = 62.4 +0.6 −0.4 eV and kT ∞ s = 38.9 +4.9 −2.9 eV, with no indication of spectral features. The contribution of the soft blackbody can also account for the flux seen in the optical band.

Black-body radiation

Position (finance)

Sample (material)

Cite

Citations (0)

The Large Observatory for X-ray Timing (LOFT)

Experimental Astronomy (2011)

M. Feroci L. Stella M. van der Klis T. J. L. Courvoisier M. Hernanz

Spectral resolution

10.1007/s10686-011-9237-2

Cite

Citations (195)

Spectral analysis of IGR J01572−7259 during its 2016 outburst

Monthly Notices of the Royal Astronomical Society (2017)

N. La Palombara P. Esposito S. Mereghetti Fabio Pintore L. Sidoli

We report on the results of the $XMM-Newton$ observation of IGR J01572-7259 during its most recent outburst in 2016 May, the first since 2008. The source reached a flux $f \sim 10^{-10}$ erg cm$^{-2}$ s$^{-1}$, which allowed us to perform a detailed analysis of its timing and spectral properties. We obtained a pulse period $P_{\rm spin}$ = 11.58208(2) s. The pulse profile is double peaked and strongly energy dependent, as the second peak is prominent only at low energies and the pulsed fraction increases with energy. The main spectral component is a power-law model, but at low energies we also detected a soft thermal component, which can be described with either a blackbody or a hot plasma model. Both the EPIC and RGS spectra show several emission lines, which can be identified with the transition lines of ionized N, O, Ne, and Fe and cannot be described with a thermal emission model. The phase-resolved spectral analysis showed that the flux of both the soft excess and the emission lines vary with the pulse phase: the soft excess disappears in the first pulse and becomes significant only in the second, where also the Fe line is stronger. This variability is difficult to explain with emission from a hot plasma, while the reprocessing of the primary X-ray emission at the inner edge of the accretion disk provides a realiable scenario. On the other hand, the narrow emission lines can be due to the presence of photoionized matter around the accreting source.

Spectral Analysis

10.1093/mnras/stx3283

Cite

Citations (3)

Screening and validation of EXTraS data products

S. Carpano F. Haberl A. De Luca A. Tiengo G. Rodriguez

Source

Cite

Citations (0)

1E 161348−5055 in the Supernova Remnant RCW 103: A Magnetar in a Young Low‐Mass Binary System?

The Astrophysical Journal (2008)

Fabio Pizzolato Monica Colpi A. De Luca S. Mereghetti A. Tiengo

We suggest that the unique X-ray source 1E 161348–5055 at the center of the supernova remnant RCW 103 consists of a neutron star in close orbit with a low-mass main-sequence star. The time signature of 6.67 hr is interpreted as the neutron star's spin period. This requires the neutron star to be endowed with a high surface magnetic field of ~1015 G. Magnetic or/and material (propeller) torques are able to rapidly spin the young neutron star down to an asymptotic, equilibrium spin period in close synchronism with the orbital period, similar to what happens in the Polar cataclysmic variables. 1E 161348–5055 could be the first case of a magnetar born in a young low-mass binary system.

Magnetar

Orbital period

X-ray binary

X-ray burster

10.1086/588084

Cite

Citations (31)