Parallax and Orbital Effects in Astrometric Microlensing With Binary Sources

Nucita, A. A.; Paolis, F. De; Ingrosso, G.; Giordano, M.; Manni, L.

doi:10.3847/0004-637x/823/2/120

Cited by 10 publications

(13 citation statements)

References 49 publications

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“…As discussed by Di Stefano et al (2013) and Nucita et al (2016), and more specifically in the case of Proxima by Sahu et al (2014), secondary gravitational lensing could occur due to the presence of a massive planet in the α Cen system. Such events are routinely observed in gravitational microlensing surveys (see e.g.…”

Section: Secondary Gravitational Lensing By a Massive Planetmentioning

confidence: 96%

Close stellar conjunctions ofαCentauri A and B until 2050

Kervella

Mignard

Mérand

et al. 2016

A&A

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The rapid proper motion of the α Cen pair (≈3.7 arcsec yr −1 ) and its location close to the galactic plane on a rich stellar background combine constructively to make them excellent candidates for close stellar conjunctions with more distant stars. Adding new differential astrometry to archival data, we have refined the orbital parameters, barycentric proper motion and parallax of α Cen and compute its apparent trajectory on sky over the coming decades. Based on NTT/SUSI2, NTT/SOFI, and VLT/NACO maps of the field stars around the trajectories of α Cen A and B, we present a catalog of the expected close conjunctions until 2050. An exceptional event will take place in early May 2028, when α Cen A will come within ρ min = 0.015 ± 0.135 arcsec of the m K = 7.8 star 2MASS 14392160-6049528 (hereafter S5). In terms of impact parameter and contrast, this is the most favorable stellar conjunction of α Cen within at least the next three decades. With an angular diameter of θ LD = 0.47 ± 0.05 mas, it is likely that S5 is a red giant or supergiant located at several kiloparsecs. The approached stars will act as moving light probes in transmission through the environment of α Cen. The observation of these close conjunctions holds great promises to search for planets and other low mass objects in the α Cen system using photometry and astrometry. The relativistic displacement of the approached star images will be observable, with significant deflection angles in the milliarcsecond range. The small impact parameter of the conjunction with S5 means that this star has a probability of 45% of entering the Einstein ring of α Cen A. The gravitational amplification of the flux of S5 could reach a factor five for the combination of the two lensed images. The proper motion, orbital parameters and parallax of α Cen will be measurable with an extreme accuracy from differential astrometry with the S stars. This will be valuable, for example to prepare the recently announced Breakthrough Starshot initiative to send interstellar nanocrafts to α Centauri.

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Section: Secondary Gravitational Lensing By a Massive Planetmentioning

confidence: 96%

Close stellar conjunctions ofαCentauri A and B until 2050

Kervella

Mignard

Mérand

et al. 2016

A&A

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“…Additionally there is the issue of binary source stars. Similar to binary lens events, binary source events can produce lightcurves that appear quite similar to PSPL events (Dominik 1998;Han & Jeong 1998), although these degeneracies can be broken by the addition of astrometric information (Nucita et al 2016).…”

Section: Binarity and Mergersmentioning

confidence: 99%

PopSyCLE: A New Population Synthesis Code for Compact Object Microlensing Events

Lam

Hosek

et al. 2020

ApJ

116

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We present a new Milky Way microlensing simulation code, dubbed PopSyCLE (Population Synthesis for Compact object Lensing Events). PopSyCLE is the first resolved microlensing simulation to include a compact object distribution derived from numerical supernovae explosion models and both astrometric and photometric microlensing effects. We demonstrate the capabilities of PopSyCLE by investigating the optimal way to find black holes (BHs) with microlensing. Candidate BHs have typically been selected from wide-field photometric microlensing surveys, such as OGLE, by selecting events with long Einstein crossing times (t E > 120 days). These events can be selected at closest approach and monitored astrometrically in order to constrain the mass of each lens; PopSyCLE predicts a BH detection rate of ∼40% for such a program. We find that the detection rate can be enhanced to ∼ 85% by selecting events with both t E > 120 days and a microlensing parallax of π E < 0.08. Unfortunately, such a selection criterion cannot be applied during the event as π E requires both pre-and post-peak photometry. However, historical microlensing events from photometric surveys can be revisited using this new selection criteria in order to statistically constrain the abundance of BHs in the Milky Way. The future WFIRST microlensing survey provides both precise photometry and astrometry and will yield individual masses of O(100 − 1000) black holes, which is at least an order of magnitude more than is possible with individual candidate follow-up with current facilities. The resulting sample of BH masses from WFIRST will begin to constrain the shape of the black hole present-day mass function, BH multiplicity, and BH kick velocity distributions.

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“…In this respect, as recently showed by Ref. 46, astrometric microlensing offers a new way to discover these kind of signatures. The total centroid shift at time t can be obtained via a weighted average on the individual source component amplifications and using as reference position the centre of light between the unlensed source components, i.e.…”

Section: Binary Sourcesmentioning

confidence: 75%

“…Hence, as in Ref. 46 one can determine the astrometric shift components by requiring that the two sources move around the common center of mass.…”

Section: Binary Sourcesmentioning

confidence: 99%

Astrometric microlensing

Nucita

Paolis

Ingrosso

et al. 2017

Int. J. Mod. Phys. D

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Astrometric microlensing will offer in the next future a new channel for investigating the nature of both lenses and sources involved in a gravitational microlensing event. The effect, corresponding to the shift of the position of the multiple image centroid with respect to the source star location, is expected to occurr on scales from micro-arcoseconds to milli-arcoseconds depending on the characteristics of the lens-source system. Here, we consider different classes of events (single/binary lens acting on a single/binary source) also accounting for additional effects including the finite source size, the blending and orbital motion. This is particularly important in the era of Gaia observations which is making possible astrometric measurements with unprecedent quality.Comment: On IJMP D, 15 pages, 6 Figure

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Parallax and Orbital Effects in Astrometric Microlensing With Binary Sources

Cited by 10 publications

References 49 publications

Close stellar conjunctions ofαCentauri A and B until 2050

Close stellar conjunctions ofαCentauri A and B until 2050

PopSyCLE: A New Population Synthesis Code for Compact Object Microlensing Events

Astrometric microlensing

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