The peculiar isolated neutron star in the Carina Nebula

Pires, Adriana Mancini; Motch, C.; Turolla, R.; Schwope, A. D.; Pilia, M.; Treves, A.; Попов, С. Б.; Janot-Pacheco, E.

doi:10.1051/0004-6361/201219161

Cited by 12 publications

(18 citation statements)

References 104 publications

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“…Similar features are also reported in the spectra of other thermally emitting INSs (Sanwal et al 2002;Haberl et al 2003;Zane et al 2004Zane et al , 2011Mori et al 2005;Haberl 2007;Schwope et al 2007;McLaughlin et al 2007;Pires et al 2012). Evidence for the presence of a narrow absorption spectral feature at energy ∼0.57 keV, possibly related to either interstellar or circumstellar highlyionised oxygen, was found in the co-added RGS spectra of the source (van Kerkwijk et al 2004;Hohle et al 2012a).…”

Section: Spectral Analysissupporting

confidence: 80%

XMM-Newtonreveals a candidate period for the spin of the “Magnificent Seven” neutron star RX J1605.3+3249

Pires¹,

Haberl²,

Zavlin³

et al. 2014

A&A

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Context. The group of seven thermally emitting isolated neutron stars (INSs) discovered by ROSAT and known as the "Magnificent Seven" (M7) is unique among the various neutron star populations. Crustal heating by means of magnetic field decay and an evolutionary link with magnetars may explain why these objects rotate more slowly and have higher thermal luminosities and magnetic field intensities than standard rotation-powered pulsars of similar age. Aims. The third brightest INS, RX J1605.3+3249, is the only object amidst the seven still lacking a detected periodicity. The source spectrum, while purely thermal with no significant magnetospheric emission, is complex and displays both narrow and broad absorption features that can potentially be used to constrain the surface component of the magnetic field, as well as the mass-to-radius ratio of the neutron star. Methods. We observed the source with the XMM-Newton Observatory for 60 ks aiming at unveiling the neutron star rotation rate and investigating its spectrum in detail. We confront our results with previous observations of the source and discuss its properties in the context of the M7 as a group and of the known population of Galactic INSs. Results. A periodic signal at P = 3.387864(16) s, most likely the neutron star spin period, is detected at the 4σ confidence level. The amplitude of the modulation was found to be energy dependent and is more significantly detected when the timing search is restricted to photons with energy higher than ∼0.5 keV. The coherent combination of the new data with a past XMM-Newton EPIC-pn observation of the source constrains the pulsar spin-down rate at the 2σ confidence level,ν ∼ −1.39 × 10 −13 Hz s −1 , implying a dipolar magnetic field of B dip ∼ 7.4 × 10 13 G. If confirmed, RX J1605.3+3249 would be the neutron star with the highest dipolar field amongst the M7. The spectrum of the source shows evidence of a cool blackbody component, as well as for the presence of two broad absorption features. Furthermore, high-resolution spectroscopy with the RGS cameras confirms the presence of a narrow absorption feature at energy ∼0.57 keV in the co-added spectrum of the source, also seen in other thermally emitting isolated neutron stars. Conclusions. Phase-resolved spectroscopy, as well as a dedicated observing campaign aimed at determining a timing solution, will give invaluable constraints on the neutron star geometry and will allow one to confirm the high value of spin down, which would place the source closer to a magnetar than any other M7 INS.

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Section: Spectral Analysissupporting

confidence: 80%

XMM-Newtonreveals a candidate period for the spin of the “Magnificent Seven” neutron star RX J1605.3+3249

Pires¹,

Haberl²,

Zavlin³

et al. 2014

A&A

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“…2XMM J104608.7−594306 (Pires et al 2012), and six potential neutron stars candidates (Townsley et al 2011) showing past supernova activity. The complicated J1048−5832 environment is thus likely linked to the northern edge of the Carina complex.…”

Section: Figmentioning

confidence: 99%

Deep optical imaging of theγ-ray pulsar J1048–5832 with the VLT

Danilenko¹,

Kirichenko

Sollerman

et al. 2013

A&A

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Context. PSR J1048-5832 is a young radio-pulsar that has recently been detected in γ-rays with Fermi, and also in X-rays with Chandra and XMM-Newton. It powers a compact pulsar wind nebula visible in X-rays and is in many ways similar to the Vela pulsar. Aims. We present deep optical observations made with the ESO Very Large Telescope to search for optical counterparts of the pulsar and its nebula and to explore their multi-wavelength emission properties. Methods. The data were obtained in the V and R bands and were compared with archival data in other spectral domains. Results. We do not detect the pulsar in the optical and derive informative upper limits of R 28. m 1 and V 28. m 4 for its brightness. Using a red-clump star method, we estimate an interstellar extinction towards the pulsar of A V ≈ 2 mag, which is consistent with the absorbing column density derived from X-rays. The respective distance agrees with the dispersion measure distance. We reanalysed the Chandra X-ray data and compared the dereddened upper limits with the unabsorbed X-ray spectrum of the pulsar. We find that regarding its optical-X-ray spectral properties this γ-ray pulsar is not distinct from other pulsars detected in both ranges. However, like the Vela pulsar, it is very inefficient in the optical and X-rays. Among a dozen optical sources overlapping with the pulsar X-ray nebula we find one with V ≈ 26. m 9 and R ≈ 26. m 3, whose colour is slightly bluer than that of the field stars and is consistent with the peculiar colours typical for pulsar nebula features. It positionally coincides with a relatively bright feature of the pulsar X-ray nebula, resembling the Crab wisp and is located in ∼2 from the pulsar. We suggest this source as a counterpart candidate to the feature. Conclusions. Based on the substantial interstellar extinction towards the pulsar and its optical inefficiency, additional optical studies should be carried out at longer wavelengths.

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“…Following the intriguing detection of a short periodic signal in the neutron star 2XMM J104608.7-594306 (Pires et al 2012), we targeted the source again with XMM-Newton, aiming at better characterising its spectral energy distribution and timing properties. The new XMM-Newton dataset unfortunately proved inconclusive in confirming the fast spin of the neutron star.…”

Section: Discussionmentioning

confidence: 99%

“…Extensive searches showed no other significant signal (above the 1σ confidence level, or with Z 2 1 > 34) across the frequency range of the analysis, and safety checks did not suggest an unknown instrumental or background origin for the periodic signal at ν * (see Pires et al 2012, for details). We also verified that the periodic signal is always present at the same frequency, independently of the details on the processing of the raw event file (e.g.…”

Section: Timing Analysismentioning

confidence: 97%

“…The likely presence of J1046 in the Carina open cluster excludes a neutron star much older than ∼10 6 yr (see discussion in Pires et al 2012). In millisecond pulsars (MSPs), as well as in middle-aged and old RPPs, a considerable fraction of the X-ray emission arises from polar caps, which are heated by back-flowing charges accelerated in the pulsar magnetosphere.…”

Section: Comparison With Other Pulsarsmentioning

confidence: 99%

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NewXMM-Newtonobservation of the thermally emitting isolated neutron star 2XMM J104608.7-594306

Pires

Motch

Turolla

et al. 2015

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Context. The isolated neutron star (INS) 2XMM J104608.7-594306 is one of the only two to be discovered through their thermal emission since the ROSAT era. Possibly a remnant of a former generation of massive stars in the Carina nebula, the exact nature of the source is unclear, and it might be unique amongst the several classes of Galactic INSs. Aims. In a first dedicated XMM-Newton observation of the source, we found intriguing evidence of a very fast spin period of P ∼ 18.6 ms at the 4σ confidence level. Moreover, spectral features in absorption have also been identified. We re-observed 2XMM J104608.7-594306 with XMM-Newton to better characterise the spectral energy distribution of the source, confirm the candidate spin period, and possibly constrain the pulsar spin-down. Methods. We used the two XMM-Newton observations of 2XMM J104608.7-594306 to perform detailed timing and spectral X-ray analysis. Both the spin-down rate and the energy of the spectral features provide estimates on the neutron star magnetic field, which are crucial for investigating the evolutionary state of the neutron star. Results. Statistically acceptable spectral fits and meaningful physical parameters for the source are only obtained when the residuals at energies 0.55 keV and 1.35 keV are taken into account by the spectral modelling. While the former can result from the inhomogeneous temperature distribution on the surface of the neutron star or can be related to a local overabundance of oxygen in the Carina nebula, the one at 1.35 keV is only satisfactorily accounted for by invoking a line in absorption. In this case, the best-fit neutron star atmosphere models constrain the hydrogen column density, the effective temperature, and the luminosity of the source within N H = (2.5−3.3) × 10 21 cm −2 , T eff = (6−10) × 10 5 K, and L X = (1.1−7.4) × 10 32 erg s −1 . The implied distance is consistent with a location in (or in front of) the Carina nebula, and radiation radii are compatible with emission originating on most of the surface. Non-thermal X-ray emission is ruled out at levels above 0.5% (3σ) of the source luminosity. Unfortunately, the second XMM-Newton observation proved inconclusive in terms of confirming (discarding) the fast candidate spin, providing an upper limit on the pulsed fraction of the source that is very close to the limiting sensitivity for detecting the modulation found previously. Conclusions. In the absence of an unambiguous period determination and an estimate of the magnetic field, the nature of the source remains open to interpretation. Its likely association with the Carina cluster and its overall spectral properties (only shared by a handful of other peculiar INSs) disfavour a standard evolutionary path or one in which the source was previously recycled by accretion in a binary system. The star 2XMM J104608.7-594306 may be similar to Calvera (1RXS J141256.0+792204), a neutron star for which the scenario of an evolved anti-magnetar has been discussed. A better age estimate and deeper radio and γ-ray l...

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The peculiar isolated neutron star in the Carina Nebula

Cited by 12 publications

References 104 publications

XMM-Newtonreveals a candidate period for the spin of the “Magnificent Seven” neutron star RX J1605.3+3249

XMM-Newtonreveals a candidate period for the spin of the “Magnificent Seven” neutron star RX J1605.3+3249

Deep optical imaging of theγ-ray pulsar J1048–5832 with the VLT

NewXMM-Newtonobservation of the thermally emitting isolated neutron star 2XMM J104608.7-594306

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