An Active, Asynchronous Companion to a Redback Millisecond Pulsar

Staden, André D. van; Antoniadis, John

doi:10.3847/2041-8213/833/1/l12

Cited by 43 publications

(12 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For instance, the worst fit to the best ELC model occurs for the data taken between 2009 November and 2010 June (χ 2 /dof = 82.3/36), while the data from 2005 October to 2006 May clearly matches the model much better (χ 2 /dof = 23.2/71). This strange phenomenology as a function of epoch is similar to that observed by van Staden & Antoniadis (2016) for the optical light curves of the redback PSR J1723-2837, which they explain with distinct groups of starspots that vary in number and lifespan over time.…”

Section: Long-term Optical Brightnesssupporting

confidence: 81%

2FGL J0846.0+2820: A New Neutron Star Binary with a Giant Secondary and Variable γ-Ray Emission

Swihart

Strader

Johnson

et al. 2017

ApJ

View full text Add to dashboard Cite

We present optical photometric and spectroscopic observations of the likely stellar counterpart to the unassociated Fermi -Large Area Telescope (LAT) γ-ray source 2FGL J0846.0+2820, selected for study based on positional coincidences of optical variables with unassociated LAT sources. Using optical spectroscopy from the SOAR telescope, we have identified a late-G giant in an eccentric (e = 0.06) 8.133 day orbit with an invisible primary. Modeling the spectroscopy and photometry together lead us to infer a heavy neutron star primary of ∼ 2M and a partially stripped giant secondary of ∼ 0.8M . Hα emission is observed in some of the spectra, perhaps consistent with the presence of a faint accretion disk. We find the γ-ray flux of 2FGL J0846.0+2820 dropped substantially in mid-2009, accompanied by an increased variation in the optical brightness, and since then it has not been detected by Fermi. The long period and giant secondary are reminiscent of the γ-ray bright binary 1FGL J1417.7-4407, which hosts a millisecond pulsar apparently in the final stages of the pulsar recycling process. The discovery of 2FGL J0846.0+2820 suggests the identification of a new subclass of millisecond pulsar binaries that are the likely progenitors of typical field millisecond pulsars.

show abstract

Section: Long-term Optical Brightnesssupporting

confidence: 81%

2FGL J0846.0+2820: A New Neutron Star Binary with a Giant Secondary and Variable γ-Ray Emission

Swihart

Strader

Johnson

et al. 2017

ApJ

View full text Add to dashboard Cite

show abstract

“…PSR J1723-2837 displays by far the largest quadrupole amplitude, J v 3 · 10 −7 , while also having the fastest period of variation, T 2 3yr. Coincidentally, it is the only spider companion which shows evidence of asynchronous rotation from optical observations (van Staden & Antoniadis 2016). This property might invalidate our primary assumption of phase-locking if the structure involved with asynchronous rotation extends beyond a thin shell of negligible mass.…”

Section: Effects Of Quadrupole Variationsmentioning

confidence: 98%

A spider timing model: accounting for quadrupole deformations and relativity in close pulsar binaries

Voisin

Breton

Summers

2019

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Spider millisecond pulsars are, along with some eclipsing post-common envelope systems and cataclysmic variables, part of an expanding category of compact binaries with low-mass companions for which puzzling timing anomalies have been observed. The most prominent type of irregularities seen in them are orbital period variations, a phenomenon which has been proposed to originate from changes in the gravitational quadrupole moment of the companion star. A physically sound modelling of the timing of these systems is key to understanding their structure and evolution. In this paper we argue that a complete timing model must account for relativistic corrections as well as rotationally and tidally induced quadrupole distortions. We solve for the resulting orbital dynamics using perturbation theory and derive the corresponding timing model in the low eccentricity limit. We find that the expected strong quadrupole deformation of the companion star results in an effective minimum orbital eccentricity. It is accompanied by a fast periastron precession which, if not taken into account, averages out any measurement of the said eccentricity. We show that, with our model, detection of both eccentricity and precession is likely to be made in many if not all spider pulsar systems. Combined with optical light curves, this will allow us to measure the apsidal motion constant, connecting the quadrupole deformation to the internal structure, and thus opening a new window into probing the nature of their exotic stellar interiors. Moreover, more accurate timing may eventually lead spider pulsars to be used for high-precision timing experiments such as pulsar timing arrays.

show abstract

“…However, higher S/N orbital X-ray lightcurves of eclipsing pulsars have revealed modulation of the X-rays throughout the orbit, and sharp peaks, often on either side of the inferior conjunction of the NS (e.g. Bogdanov et al 2011;Romani & Shaw 2011;Huang et al 2012;Bogdanov et al 2014;Hui et al 2014;de Martino et al 2015;Hui et al 2015). This has inspired interpretation of the X-rays as due to particle acceleration at the interface between the companion and pulsar winds, beamed in the direction of the particle flow (e.g.…”

Section: Eclipsing Millisecond Pulsarsmentioning

confidence: 99%

The MAVERIC survey: a hidden pulsar and a black hole candidate in ATCA radio imaging of the globular cluster NGC 6397

Zhao

Heinke

Tudor

et al. 2020

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Using a 16.2 hr radio observation by the Australia Telescope Compact Array (ATCA) and archival Chandra data, we found > 5σ radio counterparts to 4 known and 3 new X-ray sources within the half-light radius (r h ) of the Galactic globular cluster NGC 6397. The previously suggested millisecond pulsar (MSP) candidate, U18, is a steep-spectrum (S ν ∝ ν α ; α = −2.0 +0.4 −0.5 ) radio source with a 5.5 GHz flux density of 54.7 ± 4.3 µJy. We argue that U18 is most likely a "hidden" MSP that is continuously hidden by plasma shocked at the collision betwen the winds from the pulsar and companion star. The nondetection of radio pulsations so far is probably the result of enhanced scattering in this shocked wind. On the other hand, we observed the 5.5 GHz flux of the known MSP PSR J1740-5340 (U12) to decrease by a factor of >2.8 during epochs of 1.4 GHz eclipse, indicating that the radio flux is absorbed in its shocked wind. If U18 is indeed a pulsar whose pulsations are scattered, we note the contrast with U12's flux decrease in eclipse, which argues for two different eclipse mechanisms at the same radio frequency. In addition to U12 and U18, we also found radio associations for 5 other Chandra X-ray sources, four of which are likely background galaxies. The last, U97, which shows strong Hα variability, is mysterious; it may be either a quiescent black hole low-mass X-ray binary, or something more unusual.

show abstract

An Active, Asynchronous Companion to a Redback Millisecond Pulsar

Cited by 43 publications

References 39 publications

2FGL J0846.0+2820: A New Neutron Star Binary with a Giant Secondary and Variable γ-Ray Emission

2FGL J0846.0+2820: A New Neutron Star Binary with a Giant Secondary and Variable γ-Ray Emission

A spider timing model: accounting for quadrupole deformations and relativity in close pulsar binaries

The MAVERIC survey: a hidden pulsar and a black hole candidate in ATCA radio imaging of the globular cluster NGC 6397

Contact Info

Product

Resources

About