Gravitational microlensing by the galactic halo

Paczyński, B.

doi:10.1086/164140

Cited by 1,469 publications

(1,301 citation statements)

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“…The first three are the standard point-lens parameters (Paczyński 1986), i.e., the time of lens-source closest approach, the impact parameter normalized to the angular Einstein radius θ E , and the Einstein crossing time,…”

Section: Ground-based Modelmentioning

confidence: 99%

OGLE-2016-BLG-1190Lb: The First Spitzer Bulge Planet Lies Near the Planet/Brown-dwarf Boundary

Ryu¹,

Yee²,

Udalski³

et al. 2017

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We report the discovery of OGLE-2016-BLG-1190Lb, which is likely to be the first Spitzer microlensing planet in the Galactic bulge/bar, an assignation that can be confirmed by two epochs of high-resolution imaging of the combined source-lens baseline object. The planet's mass, M p =13.4±0.9 M J , places it right at the deuteriumburning limit, i.e., the conventional boundary between "planets" and "brown dwarfs." Its existence raises the question of whether such objects are really "planets" (formed within the disks of their hosts) or "failed stars" (lowmass objects formed by gas fragmentation). This question may ultimately be addressed by comparing disk and bulge/bar planets, which is a goal of the Spitzer microlens program. The host is a G dwarf, M host =0.89±0.07 M e , and the planet has a semimajor axis a∼2.0 au. We use Kepler K2 Campaign 9 microlensing data to break the lens-mass degeneracy that generically impacts parallax solutions from Earth-Spitzer observations alone, which is the first successful application of this approach. The microlensing data, derived primarily from near-continuous, ultradense survey observations from OGLE, MOA, and three KMTNet telescopes, contain more orbital information than for any previous microlensing planet, but not quite enough to accurately specify the full orbit. However, these data do permit the first rigorous test of microlensing orbital-motion measurements, which are typically derived from data taken over <1% of an orbital period.

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Section: Ground-based Modelmentioning

confidence: 99%

OGLE-2016-BLG-1190Lb: The First Spitzer Bulge Planet Lies Near the Planet/Brown-dwarf Boundary

Ryu¹,

Yee²,

Udalski³

et al. 2017

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“…We begin our modeling of the OGLE-2014-BLG-1760 light curve with a single-lens microlensing model (Paczyński et al 1986). There are three nonlinear model parameters for a singlelens event: t 0 , the time of peak magnification; u 0 , the minimum separation between source and lens in Einstein radius units; and Notes.…”

Section: Best-fit Modelmentioning

confidence: 99%

Discovery of a Gas Giant Planet in Microlensing Event Ogle-2014-BLG-1760

Bhattacharya

Bennett

Bond

et al. 2016

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We present the analysis of the planetary microlensing event OGLE-2014-BLG-1760, which shows a strong lightcurve signal due to the presence of a Jupiter mass ratio planet. One unusual feature of this event is that the source star is quite blue, with -=  V I 1.48 0.08. This is marginally consistent with a source star in the Galactic bulge, but it could possibly indicate a young source star on the far side of the disk. Assuming a bulge source, we perform a Bayesian analysis assuming a standard Galactic model, and this indicates that the planetary system resides in or near the Galactic bulge at =  D 6.9 1.1 kpc , and a projected star-planet separation of = -+ a 1.75 0.33 0.34 au. The lens-source relative proper motion is m =  6.5 1.1 rel mas yr −1 . The lens (and stellar host star) is estimated to be very faint compared to the source star, so it is most likely that it can be detected only when the lens and source stars start to separate. Due to the relatively high relative proper motion, the lens and source will be resolved to about ∼46 mas in 6-8 yr after the peak magnification. So, by 2020-2022, we can hope to detect the lens star with deep, high-resolution images.

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“…(3), the average time duration of the NS gravitational wave amplification is ∆T 2 10 2 yr, which is much longer than the typical integration time for gravitational wave detection given in Table 2 for the VIRGO detector. Such an extended event duration, in addition to giving a substantially enhanced signal, should in principle allow us to construct a Paczyński-like curve (Paczyński 1986) for microlensing of gravitational waves. From Eq.…”

Section: Nss In the Galactic Bulgementioning

confidence: 99%

Astrophysical implications of gravitational microlensing of gravitational waves

Paolis

Ingrosso

Nucita

2001

A&A

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Abstract. Astrophysical implications of gravitational microlensing of gravitational waves emitted by rotating neutron stars (NSs) are investigated. In particular, attention is focused on the following situations: i) NSs in the galactic bulge lensed by a central black hole of 2.6 10 6 M or by stars and MACHOs distributed in the galactic bulge, disk and halo between Earth and the sources; ii) NSs in globular clusters lensed by a central black hole of ∼10 3 M or by stars and MACHOs distributed throughout the Galaxy. The detection of such kind of microlensing events will give a unique opportunity for the unambiguous mapping of the central region of the Galaxy and of globular clusters. In addition, the detection of such events will provide a new test of the General Theory of Relativity. Gravitational microlensing will, moreover, increase the challenge of detecting gravitational waves from NSs.

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Gravitational microlensing by the galactic halo

Cited by 1,469 publications

References 0 publications

OGLE-2016-BLG-1190Lb: The First Spitzer Bulge Planet Lies Near the Planet/Brown-dwarf Boundary

OGLE-2016-BLG-1190Lb: The First Spitzer Bulge Planet Lies Near the Planet/Brown-dwarf Boundary

Discovery of a Gas Giant Planet in Microlensing Event Ogle-2014-BLG-1760

Astrophysical implications of gravitational microlensing of gravitational waves

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