Criteria for Sample Selection to Maximize Planet Sensitivity and Yield From Space-Based Microlens Parallax Surveys

Yee, Jennifer C.; Gould, Andrew; Beichman, Charles; Novati, S. Calchi; Carey, Sean; Gaudi, B. Scott; Henderson, Calen B.; Nataf, David M.; Penny, Matthew T.; Shvartzvald, Yossi; Zhu, Wei

doi:10.1088/0004-637x/810/2/155

Cited by 120 publications

(173 citation statements)

References 41 publications

Supporting

Mentioning

171

Contrasting

Order By: Relevance

“…(see Section 4.1 below) was redder than the default assumption for dwarfs of 0.8 by Yee et al (2015), coincidentally, the final brightness was similar.…”

Section: Spitzer Observationsmentioning

confidence: 68%

“…The team realized the high-magnification nature of OGLE-2015-BLG-1319, and thus its potential high planet sensitivity, from preliminary OGLE and MOA data, when the event was only 1.4 mag brighter than the baseline (ultimately getting 4.4 mag brighter than base-see Figure 2). Yee et al (2015) describe the Spitzer selection criteria and observing strategy for such events. The set of objective criteria is needed to both minimize selection biases, in particular regarding the presence or absence of a companion to the primary lens, and to maximize the sensitivity for detecting possible companions as well as measuring the microlens parallax.…”

Section: Spitzer Observationsmentioning

confidence: 99%

“…However, since the event was in a low-cadence OGLE field and was not observed at all by KMTNet, it failed to meet criterion B2, and thus could not be selected objectively. In addition, the estimated flux in Spitzerʼs L band on the first date of possible observations (six days later on HJD′ = 7205) and beyond, assuming the ground-based light curve, was too faint, L eff >15.9 (see definition in Yee et al 2015). Nevertheless, the team selected the event subjectively, due to its predicted high magnification, immediately announced it as a Spitzer target, and urged the follow-up teams to monitor the event in order to have high planet sensitivity.…”

Section: Spitzer Observationsmentioning

confidence: 99%

See 2 more Smart Citations

The First Simultaneous Microlensing Observations by Two Space Telescopes: Spitzer and Swift Reveal a Brown Dwarf in Event Ogle-2015-BLG-1319

Shvartzvald¹,

Li²,

Udalski³

et al. 2016

ApJ

Self Cite

View full text Add to dashboard Cite

Simultaneous observations of microlensing events from multiple locations allow for the breaking of degeneracies between the physical properties of the lensing system, specifically by exploring different regions of the lens plane and by directly measuring the "microlens parallax." We report the discovery of a 30-65M J brown dwarf orbiting a K dwarf in the microlensing event OGLE-2015-BLG-1319. The system is located at a distance of ∼5 kpc toward the Galactic Bulge. The event was observed by several ground-based groups as well as by Spitzer and Swift, allowing a measurement of the physical properties. However, the event is still subject to an eight-fold degeneracy, in particular the well-known close-wide degeneracy, and thus the projected separation between the two lens components is either ∼0.25 au or ∼45 au. This is the first microlensing event observed by Swift, with the UVOT camera. We study the region of microlensing parameter space to which Swift is sensitive, finding that though Swift could not measure the microlens parallax with respect to ground-based observations for this event, it can be important for other events. Specifically, it is important for detecting nearby brown dwarfs and free-floating planets in high magnification events.

show abstract

“…(see Section 4.1 below) was redder than the default assumption for dwarfs of 0.8 by Yee et al (2015), coincidentally, the final brightness was similar.…”

Section: Spitzer Observationsmentioning

confidence: 68%

Section: Spitzer Observationsmentioning

confidence: 99%

Section: Spitzer Observationsmentioning

confidence: 99%

See 1 more Smart Citation

The First Simultaneous Microlensing Observations by Two Space Telescopes: Spitzer and Swift Reveal a Brown Dwarf in Event Ogle-2015-BLG-1319

Shvartzvald¹,

Li²,

Udalski³

et al. 2016

ApJ

Self Cite

View full text Add to dashboard Cite

show abstract

“…Third, it is the first planet to enter the Spitzer "blind" sample whose existence was recognized prior to its choice as a Spitzer target. This seeming contradiction was clearly anticipated by Yee et al (2015a) when they established their protocols for the Galactic distribution experiment. The discovery therefore tests the well-defined, but intricate, procedures devised by Yee et al (2015a) to deal with this possibility.…”

Section: Introductionmentioning

confidence: 98%

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

Ryu¹,

Yee²,

Udalski³

et al. 2017

Self Cite

View full text Add to dashboard Cite

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.

show abstract

“…OGLE-2017-BLG-1130 was originally selected as a Spitzer target within the framework of the protocols of Yee et al (2015a). These protocols are designed to obtain an "objective sample" to measure the Galactic distribution of planets despite the fact that humans must make observing decisions based on real-time data.…”

Section: Spitzer Follow-upmentioning

confidence: 99%

OGLE-2017-BLG-1130: The First Binary Gravitational Microlens Detected from Spitzer Only

Novati

Udalski

Gould

et al. 2018

ApJ

Self Cite

View full text Add to dashboard Cite

We analyze the binary gravitational microlensing event OGLE-2017-BLG-1130 (mass ratio q∼0.45), the first published case in which the binary anomaly was detected only by the Spitzer Space Telescope. This event provides strong evidence that some binary signals can be missed by observations from the ground alone but detected by Spitzer. We therefore invert the normal procedure, first finding the lens parameters by fitting the space-based data and then measuring the microlensing parallax using ground-based observations. We also show that the normal four-fold space-based degeneracy in the single-lens case can become a weak eight-fold degeneracy in binary-lens events. Although this degeneracy is resolved in event OGLE-2017-BLG-1130, it might persist in other events.

show abstract

Criteria for Sample Selection to Maximize Planet Sensitivity and Yield From Space-Based Microlens Parallax Surveys

Cited by 120 publications

References 41 publications

The First Simultaneous Microlensing Observations by Two Space Telescopes: Spitzer and Swift Reveal a Brown Dwarf in Event Ogle-2015-BLG-1319

The First Simultaneous Microlensing Observations by Two Space Telescopes: Spitzer and Swift Reveal a Brown Dwarf in Event Ogle-2015-BLG-1319

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

OGLE-2017-BLG-1130: The First Binary Gravitational Microlens Detected from Spitzer Only

Contact Info

Product

Resources

About