Neutron Star Interior Composition Explorer X-Ray Timing of the Radio and γ-Ray Quiet Pulsars PSR J1412+7922 and PSR J1849-0001

Bogdanov, Slavko; Ho, Wynn C. G.; Enoto, T.; Guillot, Sebastien; Harding, A. K.; Jaisawal, Gaurava K.; Malacaria, C.; Manthripragada, Sridhar S.; Arzoumanian, Zaven; Gendreau, Keith C.

doi:10.3847/1538-4357/ab1b2e

Cited by 22 publications

(29 citation statements)

References 31 publications

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“…There are 12 pulsars for which there is no overlap between electromagnetic observations and the O2 run. These include two pulsars, J1412+7922 (known as Calvera) and J1849−0001, for which we only have X-ray timing observations from after O2 (Bogdanov et al 2019). 198 For these we have made the reasonable assumption that timing models are coherent for our analysis and that no timing irregularities, such as glitches, are present.…”

Section: Pulsarsmentioning

confidence: 99%

“…The O1 and O2 data sets are publicly available via the Gravitational Wave Open Science Center athttps://www.gw-openscience.org/O1 andhttps:// www.gw-openscience.org/O2, respectively (Vallisneri et al 2015).198 Subsequent to the search performed here,Bogdanov et al (2019) revised their initial timing model of J1849−0001 so that it now overlaps partially with O2. The revised model is consistent with the initial model used here, and thus the results presented here remain valid.…”

mentioning

confidence: 99%

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Searches for Gravitational Waves from Known Pulsars at Two Harmonics in 2015–2017 LIGO Data

Abbott¹,

Abbott²,

Abbott³

et al. 2019

ApJ

116

110

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We present a search for gravitational waves from 222pulsars with rotation frequencies 10 Hz. We use advanced LIGO data from its first and second observing runs spanning 2015-2017, which provides the highest-sensitivity gravitational-wavedata so far obtained. In this search we target emission from both the l=m=2 mass quadrupole mode, with a frequency at twice that of the pulsar's rotation, and the l=2, m=1 mode, with a frequency at the pulsar rotation frequency. The search finds no evidence for gravitational-wave emission from any pulsar at either frequency. For the l=m=2 mode search, we provide updated upper limits on the gravitationalwave amplitude, mass quadrupole moment, and fiducial ellipticity for 167pulsars, and the first such limits for a further 55. For 20young pulsars these results give limits that are below those inferred from the pulsars' spin-down. For the Crab and Vela pulsars our results constrain gravitational-wave emission to account for less than 0.017%and 0.18%of the spin-down luminosity, respectively. For the recycled millisecond pulsar J0711 −6830our limits are only a factor of 1.3above the spin-down limit, assuming the canonical value of 10 38 kg m 2 for the star's moment of inertia, and imply a gravitational-wave-derived upper limit on the star's ellipticity of 1.2×10 −8. We also place new limits on the emission amplitude at the rotation frequency of the pulsars.

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Section: Pulsarsmentioning

confidence: 99%

mentioning

confidence: 99%

Searches for Gravitational Waves from Known Pulsars at Two Harmonics in 2015–2017 LIGO Data

Abbott¹,

Abbott²,

Abbott³

et al. 2019

ApJ

116

110

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“…The resulting ObsId grouping is given in the last column of Table 4. We started the phase fitting with only the ν and ν terms, obtaining values consistent with those of Bogdanov et al (2019). However, when we added the data of the second half of 2019, the fit residuals indicated the need of the second and then of the third derivative of the frequency.…”

Section: Timing Analysismentioning

confidence: 99%

“…The observations of Calvera used here were obtained from 15/9/2017 to 26/2/2021 (see Table 4). Results of the data obtained before October 2018 have been published by Bogdanov et al (2019).…”

Section: Observations and Data Analysismentioning

confidence: 99%

NICER study of pulsed thermal X-rays from Calvera: a neutron star born in the Galactic halo?

Mereghetti,

Rigoselli,

Taverna

et al. 2021

Preprint

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Calvera (1RXS J141256.0+792204) is an isolated neutron star detected only through its thermal X-ray emission. Its location at high Galactic latitude (b = +37 • ) is unusual if Calvera is a relatively young pulsar, as suggested by its spin period (59 ms) and period derivative (3.2×10 −15 Hz s −1 ). Using the Neutron Star Interior Composition Explorer (NICER), we obtained a phase-connected timing solution spanning four years which allowed us to measure the second derivative of the frequency ν = −2.5 × 10 −23 Hz s −2 and to reveal timing noise consistent with that of normal radio pulsars. A magnetized hydrogen atmosphere model, covering the entire star surface, provides a good description of the phase-resolved spectra and energy-dependent pulsed fraction. However, we find that a temperature map more anisotropic than that produced by a dipole field is required, with a hotter zone concentrated towards the poles. By adding two small polar caps, we find that the surface effective temperature and that of the caps are ∼0.1 and ∼0.36 keV, respectively. The inferred distance is ∼3.3 kpc. We confirm the presence of an absorption line at 0.7 keV associated to the emission from the whole star surface, difficult to interpret as a cyclotron feature and more likely originating from atomic transitions. We searched for pulsed γ-ray emission by folding seven years of Fermi -LAT data using the X-ray ephemeris, but no evidence for pulsations was found. Our results favour the hypothesis that Calvera is a normal rotation-powered pulsar, with the only peculiarity of being born at a large height above the Galactic disk.

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“…NICER was designed to reach about 5% accuracy on the determination of the mass and the radius of the closely PSR J0437-4715 by directly fitting the phase-resolved shape of its X-ray pulses. In a recent paper, the authors use NICER observations to update the X-ray timing of radio-and γ-quiet pulsars PSR J1412+7922 and PSR J1849-0001 [273]. Moreover, five X-ray bursts on 4U 1820-30 were already detected with NICER.…”

Section: Summary and Future Prospectsmentioning

confidence: 99%

Phase transitions in neutron stars and their links to gravitational waves

Orsaria

Malfatti

Mariani

et al. 2019

J. Phys. G: Nucl. Part. Phys.

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The recent direct observation of gravitational wave event GW 170817 and its GRB170817A signal has opened up a new window to study neutron stars and heralds a new era of Astronomy referred to as the Multimessenger Astronomy. Both gravitational and electromagnetic waves from a single astrophysical source have been detected for the first time. This combined detection offers an unprecedented opportunity to place constraints on the neutron star matter equation of state. The existence of a possible hadron-quark phase transition in the central regions of neutron stars is associated with the appearance of g-modes, which are extremely important as they could signal the presence of a pure quark matter core in the centers of neutron stars. Observations of g-modes with frequencies between 1 kHz and 1.5 kHz could be interpreted as evidence of a sharp hadron-quark phase transition in the cores of neutron stars. In this article, we shall review the description of the dense matter composing neutron stars, the determination of the equation of state of such matter, and the constraints imposed by astrophysical observations of these fascinating compact objects. arXiv:1907.04654v1 [astro-ph.HE]

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Neutron Star Interior Composition Explorer X-Ray Timing of the Radio and γ-Ray Quiet Pulsars PSR J1412+7922 and PSR J1849-0001

Cited by 22 publications

References 31 publications

Searches for Gravitational Waves from Known Pulsars at Two Harmonics in 2015–2017 LIGO Data

Searches for Gravitational Waves from Known Pulsars at Two Harmonics in 2015–2017 LIGO Data

NICER study of pulsed thermal X-rays from Calvera: a neutron star born in the Galactic halo?

Phase transitions in neutron stars and their links to gravitational waves

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