Moa-2010-BLG-311: A Planetary Candidate Below the Threshold of Reliable Detection

Yee, Jennifer C.; Hung, L. W.; Bond, I. A.; Allen, William H.; Monard, L. A. G.; Albrow, M. D.; Fouqué, P.; Dominik, M.; Tsapras, Y.; Udalski, A.; Gould, Andrew; Zellem, Robert T.; Bos, M.; Christie, Grant; DePoy, D. L.; Dong, Subo; Drummond, J.; Gaudi, B. Scott; Gorbikov, E.; Han, Cheongho; Kaspi, S.; Klein, Nir; Lee, Chung-Uk; Maoz, Dan; McCormick, J.; Moorhouse, D.; Natusch, T.; Nola, M.; Park, B.-G.; Pogge, Richard W.; Polishook, David; Shporer, Avi; Shvartzvald, Yossi; Skowron, J.; Thornley, G.; Abe, F.; Bennett, D. P.; Botzler, C. S.; Chote, P.; Freeman, Matthew; Fukui, A.; Furusawa, K.; Harris, P.; Itow, Y.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Miyake, N.; Ohnishi, Koji; Rattenbury, N. J.; Saito, To.; Sullivan, D. J.; Sumi, T.; Suzuki, D.; Sweatman, W. L.; Tristram, P. J.; Wada, K.; Yock, P. C. M.; Szymański, M. K.; Soszyński, I.; Kubiak, M.; Poleski, R.; Ulaczyk, K.; Pietrzyński, G.; Wyrzykowski, Ł.; Bachelet, E.; Batista, V.; Beatty, Thomas G.; Beaulieu, J. P.; Bennett, C. S.; Bowens-Rubin, R.; Brillant, S.; Caldwell, J. A. R.; Cassan, A.; Cole, A. A.; Corrales, E.; Coutures, C.; Dieters, S.; Prester, D. Dominis; Donatowicz, J.; Greenhill, J.; Henderson, Calen B.; Kubas, D.; Marquette, J. B.; Martín, Roland; Menzies, John; Shappee, B. J.; Williams, A.; Wouters, D.; Saders, Jennifer L. van; Zub, M.; Street, R. A.; Horne, K.; Bramich, D. M.; Steele, I. A.; Alsubai, K. A.; Bozza, V.; Browne, P.; Burgdorf, M.; Novati, S. Calchi; Dodds, P.; Finet, F.; Gerner, T.; Hardis, S.; Harpsøe, K.; Hessman, F. V.; Hinse, T. C.; Hundertmark, M.; Jørgensen, U. G.; Kains, N.; Kerins, E.; Liebig, C.; Mancini, L.; Mathiasen, M.; Penny, Matthew T.; Proft, S.; Rahvar, S.; Ricci, Davide; Sahu, K. C.; Scarpetta, G.; Schäfer, Sebastian; Schönebeck, F.; Snodgrass, C.; Southworth, J.; Surdej, Jean; Wambsganß, J.

doi:10.1088/0004-637x/769/1/77

Cited by 19 publications

(20 citation statements)

References 30 publications

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“…Our choice of ∆χ 2 threshold is the de facto standard among microlensing simulations (e.g., Bennett & Rhie 2002;Bennett et al 2003;Penny et al 2013;Henderson et al 2014a). Yee et al (2012) and Yee et al (2013) discussed the issue of the detection threshold in survey data for high magnification events, and concluded that for one particular event a clear planetary anomaly in the full data set might be marginally undetectable in a truncated survey data set at ∆χ 2 ≈ 170. For a uniform survey data set, and a search that included low-magnification events, Suzuki et al (2016) used a ∆χ 2 threshold of 100.…”

Section: Simulating the Wfirst Microlensing Surveymentioning

confidence: 99%

“…There is also significant work needed on microlensing simulations to better understand the information that WFIRST will be able to measure for each planet it finds. This is especially the case for host mass measurements, which will be possible though one or more of the techniques: detecting the host as it separates from the source and measuring image elongation, color-dependent centroid shifts or directly resolving the lens (e.g., Bennett et al 2007;Henderson 2015;Bhattacharya et al 2017), measuring the microlensing parallax with or without finite source measurements (e.g., Yee et al 2013;Yee 2015;Bachelet et al 2018), or even measuring astrometric microlensing (Gould & Yee 2014). The error budget of these measurements is likely to be dominated by systematic errors, and so more detailed end-to-end simulations of the stacking, photometry and astrometry pipelines are likely necessary in order to fully understand WFIRST's capabilities.…”

Section: Future Improvementsmentioning

confidence: 99%

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Predictions of the WFIRST Microlensing Survey. I. Bound Planet Detection Rates

Penny

Gaudi

Kerins

et al. 2019

ApJS

213

266

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The Wide Field InfraRed Survey Telescope (WFIRST) is the next NASA astrophysics flagship mission, to follow the James Webb Space Telescope (JWST). The WFIRST mission was chosen as the top-priority large space mission of the 2010 astronomy and astrophysics decadal survey in order to achieve three primary goals: to study dark energy via a wide-field imaging survey, to study exoplanets via a microlensing survey, and to enable a guest observer program. Here we assess the ability of the several WFIRST designs to achieve the goal of the microlensing survey to discover a large sample of cold, low-mass exoplanets with semimajor axes beyond roughly one AU, which are largely impossible to detect with any other technique. We present the results of a suite of simulations that span the full range of the proposed WFIRST architectures, from the original design envisioned by the decadal survey, to the current design, which utilizes a 2.4-m telescope donated to NASA. By studying such a broad range of architectures, we are able to determine the impact of design trades on the expected yields of detected exoplanets. In estimating the yields we take particular care to ensure that our assumed Galactic model predicts microlensing event rates that match observations, consider the impact that inaccuracies in the Galactic model might have on the yields, and ensure that numerical errors in lightcurve computations do not bias the yields for the smallest mass exoplanets. For the nominal baseline WFIRST design and a fiducial planet mass function, we predict that a total of ∼1400 bound exoplanets with mass greater than ∼0.1 M ⊕ should be detected, including ∼200 with mass 3 M ⊕ . WFIRST should have sensitivity to planets with mass down to ∼0.02 M ⊕ , or roughly the mass of Ganymede.

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Section: Simulating the Wfirst Microlensing Surveymentioning

confidence: 99%

Section: Future Improvementsmentioning

confidence: 99%

Predictions of the WFIRST Microlensing Survey. I. Bound Planet Detection Rates

Penny

Gaudi

Kerins

et al. 2019

ApJS

213

266

View full text Add to dashboard Cite

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“…where k is a linear scaling factor and e min a minimum error added in quadrature. In A1999 the traditional metric of forcing χ 2 /dof = 1 for each dataset (Yee et al 2013) was used to arrive at a k ∼ 1.8, with the e min remaining unused. However as in Bachelet et al (2018) we avoid using this determination as it is is only relevant for linear models (Andrae et al 2010).…”

Section: Error-bar Rescalingmentioning

confidence: 99%

Confirmation of the Stellar Binary Microlensing Event, Macho 97-BLG-28

Blackman

Beaulieu

Cole

et al. 2020

ApJ

Self Cite

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The high-magnification microlensing event MACHO-97-BLG-28 was previously determined to be a binary system composed either of two M dwarfs, or an M dwarf and a brown dwarf. We present a revised light-curve model using additional data from the Mt. Stromlo 74" telescope and more recent models of stellar limb darkening. We find a lensing system with a larger mass ratio, q = 0.28±0.01, and smaller projected separation, s = 0.61±0.01, than that presented in the original study. We revise the estimate of the lens-source relative proper motion to µ rel = 2.8 ± 0.5 mas yr −1 , which indicates that 16.07 years after the event maximum the lens and source should have separated by 46±8 mas. We revise the source star radius using more recent reddening maps and angular diameter-color relations to R * = (10.3 ± 1.9)R . K and J-band adaptive optics images of the field taken at this epoch using the NIRC2 imager on the Keck telescope show that the source and lens are still blended, consistent with our light-curve model. With no statistically significant excess flux detection we constrain the mass, M L = 0.24 +0.28 −0.12 M , and distance, D L = 7.0 ± 1.0 kpc, of the lensing system. This supports the interpretation of this event being a stellar binary in the galactic bulge. This lens mass gives a companion mass of M = 0.07 +0.08 −0.04 M , close to the boundary between being a star and a brown dwarf.

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“…For both models, we use χ 2 criterion to test the detectability of a planetary signal. This criterion is based on the difference between χ 2 of two models; We accept the hypothesis of an exoplanet detection whenever ∆χ 2 150 which is a reasonable threshold for space-based telescopes (Bennett & Rhie 2002; Penny et al 2019;Bennett et al 2003;Penny et al 2013;Henderson et al 2014;Yee et al 2012Yee et al , 2013.…”

Section: Detectability Of the Simulated Eventsmentioning

confidence: 99%

Detection of exoplanet as a binary source of microlensing events in WFIRST survey

Bagheri

Sajadian

Rahvar

2019

Monthly Notices of the Royal Astronomical Society

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We investigate the possibility of exoplanet detection orbiting source stars in microlensing events through WFIRST observations. We perform a Monto Carlo simulation on the detection rate of exoplanets via microlensing, assuming that each source star has at least one exoplanet. The exoplanet can reflect part of the light from the parent star or emit internal thermal radiation. In this new detection channel, we use microlensing as an amplifier to magnify the reflection light from the planet. In the literature, this mode of detecting exoplanets has been investigated much less than the usual mode in which the exoplanets are considered as one companion in binary lens events. Assuming 72 days of observation per season with the cadence of 15 minutes, we find the probability of rocky planet detection with this method to be virtually zero. However, there is non-zero probability, for the detection of Jovian planets. We estimate the detection rates of the exoplanets by this method, using WFIRST observation to be 0.012% in single lens events and 0.9% in the binary lens events.

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Moa-2010-BLG-311: A Planetary Candidate Below the Threshold of Reliable Detection

Cited by 19 publications

References 30 publications

Predictions of the WFIRST Microlensing Survey. I. Bound Planet Detection Rates

Predictions of the WFIRST Microlensing Survey. I. Bound Planet Detection Rates

Confirmation of the Stellar Binary Microlensing Event, Macho 97-BLG-28

Detection of exoplanet as a binary source of microlensing events in WFIRST survey

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