Predicting gravitational lensing by stellar remnants

Harding, Alexander J.; Stefano, Rosanne Di; Lépine, Sébastien; Urama, J. O.; Pham, Dang T.; Baker, Claire

doi:10.1093/mnras/stx2985

Cited by 15 publications

(12 citation statements)

References 44 publications

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“…High proper motion stars are generally nearby and therefore have welldetermined distances, which allows the lens mass to be found with high accuracy. The advent of data from the Gaia satellite, which is providing parallaxes and proper motions for over a billion stars in the Galaxy, makes it timely to look at Paczynski's suggestion anew (e.g., Belokurov & Evans 2002;Harding et al 2018).…”

Section: Introductionmentioning

confidence: 99%

A predicted astrometric microlensing event by a nearby white dwarf

McGill

Smith

Evans

et al. 2018

Monthly Notices of the Royal Astronomical Society: Letters

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We used the Tycho-Gaia Astrometric Solution catalogue, part of Gaia Data Release 1, to search for candidate astrometric microlensing events expected to occur within the remaining lifetime of the Gaia satellite. Our search yielded one promising candidate. We predict that the nearby DQ type white dwarf LAWD 37 (WD 1142-645) will lens a background star and will reach closest approach on November 11th 2019 (± 4 days) with impact parameter 380 ± 10 mas. This will produce an apparent maximum deviation of the source position of 2.8 ± 0.1 mas. In the most propitious circumstance, Gaia will be able to determine the mass of LAWD 37 to ∼ 3%. This mass determination will provide an independent check on atmospheric models of white dwarfs with helium rich atmospheres, as well as tests of white dwarf mass radius relationships and evolutionary theory.

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Section: Introductionmentioning

confidence: 99%

A predicted astrometric microlensing event by a nearby white dwarf

McGill

Smith

Evans

et al. 2018

Monthly Notices of the Royal Astronomical Society: Letters

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“…Sahu et al (1998) and Salim & Gould (2000) made some predictions for future astrometric microlensing events. Harding et al (2018) estimated the astrometric microlensing rate for known stellar remnants, and McGill et al (2018) used the GAIA-TGAS catalog (Lindegren et al 2016) to make predictions for astrometric microlensing events. Furthermore, Bramich et al (2018) and Mustill et al (2018) made some predictions for microlensing events in the next ten and twenty years, respectively, based on the GAIA-DR2 catalog.…”

Section: Introductionmentioning

confidence: 99%

Toward the Measurement of the Mass of Isolated Neutron Stars: Prediction of Future Astrometric Microlensing Events by Pulsars

Ofek

2018

ApJ

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The mass of single neutron stars (NSs) can be measured using astrometric microlensing events. In such events, the center-of-light motion of a star lensed by a NS will deviate from the expected non-lensed motion and this deviation can be used to measure the mass of the NS. I search for future conjunctions between pulsars, with measured proper motion, and stars in the GAIA-DR2 catalog. I identified one candidate event of a star that will possibly be lensed by a pulsar during the next ten years in which the expected light deflection of the background star will deviate from the non-lensed motion by more than 50 µas. Given the position and proper motion of PSR J0846 − 3533, it will possibly pass ∼ 0.2 ′′ from a 19.0 G magnitude background star in 2022.9. Further assuming a 1.4 M ⊙ NS, the expected maximum deviation of the background star images from the uniform-rate plus parallax motion will be 91 µas. This pulsar position has a relatively large uncertainty and therefore additional observations are required in order to verify this event. I briefly discuss the opposite case, in which a pulsar is being lensed by a star. Such events can be used to measure the stellar mass via pulsar timing measurements. I do not find good candidates for such events with predicted variations in the pulsar period derivative (Ṗ ), divided by 1 s, exceeding 10 −20 s −1 . Since only about 10% of the known pulsars have measured proper motions, there is potential for an increase in the number of predicted pulsar lensing events.

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“…With about 3800 white dwarfs in our sample of good HPMS, we would expect about 20 microlensing events between 2030 and 2065.5 (where our sample shows a constant behaviour). However, for the same time range, we found 146 events caused by a white dwarfs, with an expected shift larger than 0.3 mas (the detection limit in Harding et al (2018)). This would lead to an event rate of 1.1 • 10 −2 .…”

Section: Events Caused By White Dwarfsmentioning

confidence: 60%

“…This increases the importance of direct mass measurements for white dwarfs. Harding et al (2018) estimates the event rate of astrometric microlensing events caused by stellar remnants. For Gaia DR2 sources and white dwarfs as lenses, they estimates 1.52 • 10 −3 events per white dwarf per decade.…”

Section: Events Caused By White Dwarfsmentioning

confidence: 99%

“…In 2000, Salim & Gould (2000) systematically searched for astrometric-microlensing events for the first time, followed by several studies based on non Gaia proper motions (Proft et al 2011;Lépine & DiStefano 2012;Harding et al 2018). Nowadays the most precise predictions make use of astrometric data from the Gaia satellite (Gaia Collaboration et al 2016).…”

Section: Introductionmentioning

confidence: 99%

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Prediction of astrometric microlensing events from Gaia DR2 proper motions

Klüter

Bastian

Demleitner

et al. 2018

A&A

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Context. Astrometric gravitational microlensing is an excellent tool to determine the mass of stellar objects. Using precise astrometric measurements of the lensed position of a background source in combination with accurate predictions of the positions of the lens and the unlensed source it is possible to determine the mass of the lens with an accuracy of a few percent. Aims. Making use of the recently published Gaia Data Release 2 (DR2) catalogue, we want to predict astrometric microlensing events caused by foreground stars with high proper motion passing a background source in the coming decades. Methods. We selected roughly 148 000 high-proper-motion stars from Gaia DR2 with µ tot > 150 mas/yr as potential lenses. We then searched for background sources close to their paths. Using the astrometric parameters of Gaia DR2, we calculated the future positions of source and lens. With a nested-intervals algorithm we determined the date and separation of the closest approach. Using Gaia DR2 photometry we determined an approximate mass of the lens, which we used to calculate the expected microlensing effects. Results. We predict 3914 microlensing events caused by 2875 different lenses between 2010 and 2065, with expected shifts larger than 0.1 mas between the lensed and unlensed positions of the source. Of those, 513 events are expected to happen between 2014.5 -2026.5 and might be measured by Gaia. For 127 events we also expect a magnification between 1 mmag and 3 mag.Conclusions.

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Predicting gravitational lensing by stellar remnants

Cited by 15 publications

References 44 publications

A predicted astrometric microlensing event by a nearby white dwarf

A predicted astrometric microlensing event by a nearby white dwarf

Toward the Measurement of the Mass of Isolated Neutron Stars: Prediction of Future Astrometric Microlensing Events by Pulsars

Prediction of astrometric microlensing events from Gaia DR2 proper motions

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