ORCID Profile
0000-0002-3202-0343
Current Organisation
University of St Andrews
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Publisher: American Astronomical Society
Date: 20-05-2000
DOI: 10.1086/308842
Publisher: American Astronomical Society
Date: 20-03-2000
DOI: 10.1086/308561
Publisher: EDP Sciences
Date: 05-2013
Publisher: American Astronomical Society
Date: 26-03-2010
Publisher: American Astronomical Society
Date: 16-08-2011
Publisher: American Astronomical Society
Date: 10-03-2016
Publisher: American Astronomical Society
Date: 19-10-2009
Publisher: American Astronomical Society
Date: 02-02-2010
Publisher: American Astronomical Society
Date: 07-10-2010
Publisher: American Astronomical Society
Date: 16-10-2015
Publisher: American Astronomical Society
Date: 11-2013
Publisher: American Astronomical Society
Date: 09-06-2017
Publisher: American Astronomical Society
Date: 10-05-2000
DOI: 10.1086/308798
Publisher: American Astronomical Society
Date: 07-11-2016
Publisher: American Astronomical Society
Date: 06-07-2012
Publisher: EDP Sciences
Date: 07-2010
Publisher: EDP Sciences
Date: 12-04-2011
Publisher: American Astronomical Society
Date: 29-08-2016
Publisher: Oxford University Press (OUP)
Date: 02-07-2012
Publisher: EDP Sciences
Date: 25-06-2013
Publisher: EDP Sciences
Date: 23-04-2004
Publisher: American Astronomical Society
Date: 27-01-2014
Publisher: EDP Sciences
Date: 08-10-2009
Publisher: EDP Sciences
Date: 26-11-2010
Publisher: Ubiquity Press, Ltd.
Date: 2022
DOI: 10.5334/DSJ-2022-001
Publisher: American Astronomical Society
Date: 10-09-1999
DOI: 10.1086/307699
Publisher: American Astronomical Society
Date: 18-08-2023
Abstract: We present an analysis of microlensing event OGLE-2019-BLG-0825. This event was identified as a planetary candidate by preliminary modeling. We find that significant residuals from the best-fit static binary-lens model exist and a xallarap effect can fit the residuals very well and significantly improves χ 2 values. On the other hand, by including the xallarap effect in our models, we find that binary-lens parameters such as mass ratio, q , and separation, s , cannot be constrained well. However, we also find that the parameters for the source system such as the orbital period and semimajor axis are consistent between all the models we analyzed. We therefore constrain the properties of the source system better than the properties of the lens system. The source system comprises a G-type main-sequence star orbited by a brown dwarf with a period of P ∼ 5 days. This analysis is the first to demonstrate that the xallarap effect does affect binary-lens parameters in planetary events. It would not be common for the presence or absence of the xallarap effect to affect lens parameters in events with long orbital periods of the source system or events with transits to caustics, but in other cases, such as this event, the xallarap effect can affect binary-lens parameters.
Publisher: Oxford University Press (OUP)
Date: 10-07-2019
Abstract: We present the analysis of the event OGLE-2017-BLG-1186 from the 2017 Spitzer microlensing c aign. This is a remarkable microlensing event because its source is photometrically bright and variable, which makes it possible to perform an asteroseismic analysis using ground-based data. We find that the source star is an oscillating red giant with average time-scale of ∼9 d. The asteroseismic analysis also provides us source properties including the source angular size (∼27 $\\mu$as) and distance (∼11.5 kpc), which are essential for inferring the properties of the lens. When fitting the light curve, we test the feasibility of Gaussian processes (GPs) in handling the correlated noise caused by the variable source. We find that the parameters from the GP model are generally more loosely constrained than those from the traditional χ2 minimization method. We note that this event is the first microlensing system for which asteroseismology and GPs have been used to account for the variable source. With both finite-source effect and microlens parallax measured, we find that the lens is likely a ∼0.045 M⊙ brown dwarf at distance ∼9.0 kpc, or a ∼0.073 M⊙ ultracool dwarf at distance ∼9.8 kpc. Combining the estimated lens properties with a Bayesian analysis using a Galactic model, we find a $\\sim 35{{\\ \\rm per\\ cent}}$ probability for the lens to be a bulge object and $\\sim 65{{\\ \\rm per\\ cent}}$ to be a background disc object.
Publisher: American Astronomical Society
Date: 11-2019
Publisher: American Astronomical Society
Date: 12-10-2011
Publisher: American Astronomical Society
Date: 02-03-2016
Publisher: American Astronomical Society
Date: 10-02-2002
DOI: 10.1086/337987
Publisher: American Astronomical Society
Date: 04-2001
DOI: 10.1086/319635
Publisher: American Astronomical Society
Date: 23-04-2013
Publisher: American Astronomical Society
Date: 11-2004
DOI: 10.1086/423665
Publisher: American Astronomical Society
Date: 28-06-2016
Publisher: American Astronomical Society
Date: 04-06-2009
Publisher: EDP Sciences
Date: 08-2015
Publisher: American Astronomical Society
Date: 28-01-2011
Publisher: American Astronomical Society
Date: 26-10-2016
Publisher: American Astronomical Society
Date: 10-09-1999
DOI: 10.1086/307681
Publisher: EDP Sciences
Date: 13-05-2005
Publisher: American Astronomical Society
Date: 09-2000
DOI: 10.1086/309340
Publisher: American Astronomical Society
Date: 10-06-2002
DOI: 10.1086/340191
Publisher: American Astronomical Society
Date: 07-09-2030
Publisher: American Astronomical Society
Date: 23-07-2020
Publisher: American Astronomical Society
Date: 14-10-2010
Publisher: Oxford University Press (OUP)
Date: 09-12-2016
Publisher: American Astronomical Society
Date: 23-11-2015
Publisher: Oxford University Press (OUP)
Date: 10-2013
Publisher: American Astronomical Society
Date: 17-08-2010
Publisher: American Astronomical Society
Date: 07-04-2014
Publisher: American Astronomical Society
Date: 13-08-2012
Publisher: American Astronomical Society
Date: 02-2012
Publisher: American Astronomical Society
Date: 02-08-2022
Abstract: We report on the observations, analysis and interpretation of the microlensing event MOA-2019-BLG-008. The observed anomaly in the photometric light curve is best described through a binary lens model. In this model, the source did not cross caustics and no finite-source effects were observed. Therefore, the angular Einstein ring radius θ E cannot be measured from the light curve alone. However, the large event duration, t E ∼ 80 days, allows a precise measurement of the microlensing parallax π E . In addition to the constraints on the angular radius θ * and the apparent brightness I s of the source, we employ the Besançon and GalMod galactic models to estimate the physical properties of the lens. We find excellent agreement between the predictions of the two galactic models: the companion is likely a resident of the brown dwarf desert with a mass M p ∼ 30 M Jup , and the host is a main-sequence dwarf star. The lens lies along the line of sight to the Galactic bulge, at a distance of ≤4 kpc. We estimate that in about 10 yr the lens and source will be separated by ∼55 mas, and it will be possible to confirm the exact nature of the lensing system by using high-resolution imaging from ground- or space-based observatories.
Publisher: Oxford University Press (OUP)
Date: 29-01-2019
DOI: 10.1093/MNRAS/STZ306
Publisher: American Astronomical Society
Date: 30-05-2012
Publisher: American Astronomical Society
Date: 11-02-2019
Publisher: American Astronomical Society
Date: 23-05-2016
Publisher: American Astronomical Society
Date: 12-11-2013
Publisher: EDP Sciences
Date: 04-03-2008
Publisher: American Astronomical Society
Date: 20-10-2016
Publisher: American Astronomical Society
Date: 20-12-2004
DOI: 10.1086/425678
Publisher: American Astronomical Society
Date: 20-06-2011
Publisher: American Astronomical Society
Date: 28-04-2015
Publisher: Wiley
Date: 30-07-2019
DOI: 10.1002/FEE.2084
Publisher: American Astronomical Society
Date: 27-04-2015
Publisher: American Astronomical Society
Date: 31-07-2012
Publisher: American Astronomical Society
Date: 18-02-2010
Publisher: American Astronomical Society
Date: 20-10-2003
DOI: 10.1086/378196
Publisher: IOP Publishing
Date: 25-10-2016
Publisher: American Astronomical Society
Date: 28-12-2017
Publisher: Springer Science and Business Media LLC
Date: 2006
DOI: 10.1038/NATURE04441
Abstract: In the favoured core-accretion model of formation of planetary systems, solid planetesimals accumulate to build up planetary cores, which then accrete nebular gas if they are sufficiently massive. Around M-dwarf stars (the most common stars in our Galaxy), this model favours the formation of Earth-mass (M(o)) to Neptune-mass planets with orbital radii of 1 to 10 astronomical units (au), which is consistent with the small number of gas giant planets known to orbit M-dwarf host stars. More than 170 extrasolar planets have been discovered with a wide range of masses and orbital periods, but planets of Neptune's mass or less have not hitherto been detected at separations of more than 0.15 au from normal stars. Here we report the discovery of a 5.5(+5.5)(-2.7) M(o) planetary companion at a separation of 2.6+1.5-0.6 au from a 0.22+0.21-0.11 M(o) M-dwarf star, where M(o) refers to a solar mass. (We propose to name it OGLE-2005-BLG-390Lb, indicating a planetary mass companion to the lens star of the microlensing event.) The mass is lower than that of GJ876d (ref. 5), although the error bars overlap. Our detection suggests that such cool, sub-Neptune-mass planets may be more common than gas giant planets, as predicted by the core accretion theory.
Publisher: Wiley
Date: 2009
Publisher: American Astronomical Society
Date: 08-2001
DOI: 10.1086/323141
Publisher: Springer Science and Business Media LLC
Date: 11-2003
DOI: 10.1038/NATURE10684
Abstract: Most known extrasolar planets (exoplanets) have been discovered using the radial velocity or transit methods. Both are biased towards planets that are relatively close to their parent stars, and studies find that around 17-30% (refs 4, 5) of solar-like stars host a planet. Gravitational microlensing, on the other hand, probes planets that are further away from their stars. Recently, a population of planets that are unbound or very far from their stars was discovered by microlensing. These planets are at least as numerous as the stars in the Milky Way. Here we report a statistical analysis of microlensing data (gathered in 2002-07) that reveals the fraction of bound planets 0.5-10 AU (Sun-Earth distance) from their stars. We find that 17(+6)(-9)% of stars host Jupiter-mass planets (0.3-10 M(J), where M(J) = 318 M(⊕) and M(⊕) is Earth's mass). Cool Neptunes (10-30 M(⊕)) and super-Earths (5-10 M(⊕)) are even more common: their respective abundances per star are 52(+22)(-29)% and 62(+35)(-37)%. We conclude that stars are orbited by planets as a rule, rather than the exception.
Publisher: American Astronomical Society
Date: 11-08-2015
Publisher: EDP Sciences
Date: 25-10-2012
Publisher: EDP Sciences
Date: 12-09-2006
Publisher: American Astronomical Society
Date: 27-12-2020
Publisher: American Astronomical Society
Date: 10-03-2001
DOI: 10.1086/319437
Publisher: American Astronomical Society
Date: 22-03-2016
Publisher: American Astronomical Society
Date: 14-11-2012
Publisher: PeerJ
Date: 13-03-2018
DOI: 10.7287/PEERJ.PREPRINTS.26672V2
Abstract: Public support for research depends, in part, on the eventual societal benefits from research. Maintaining that support likely requires sustained engagement between the research community and the broader public. Yet, there is little organized effort to evaluate and reward such engagement in addition to research and teaching activities. Using data from an international survey of 1092 researchers (634 established researchers and 458 students) in 55 countries and 315 research institutions, we find that institutional recognition of engagement activities is perceived as being undervalued relative to its societal benefit. Many researchers report that their institutions would not reward engagement activities despite mission statements promoting engagement. Further, those institutions that actually measure engagement activities are perceived to do so in a limited capacity (respondents perceived that on average, 2 of the 7 dimensions of engagement we considered were reflected in evaluations). Most researchers are strongly motivated to engage for selfless reasons, which suggests that strong self-oriented incentives may have unintended effects. Perhaps by recognizing the important engagement activities of researchers, institutions can better achieve their institutional missions and bolster the crucial contributions of researchers to society.
Publisher: American Astronomical Society
Date: 20-06-2002
DOI: 10.1086/340310
Publisher: EDP Sciences
Date: 27-03-2013
Publisher: American Astronomical Society
Date: 27-11-2013
Publisher: American Astronomical Society
Date: 24-09-2014
Publisher: American Astronomical Society
Date: 17-01-2013
Publisher: American Astronomical Society
Date: 06-05-2013
Publisher: Research Square Platform LLC
Date: 09-06-2023
DOI: 10.21203/RS.3.RS-3011208/V1
Abstract: The assessment of research performance is widely seen as a vital tool in upholding the highest standards of quality, with selection and competition believed to drive progress. Specifically, academic institutions need to take critical decisions on hiring and promotion, while facing external pressure by also being subject to research assessment [1–4]. Here, we present the first truly global outlook to research assessment for career progression, based on 159 institutional and 37 national policies from a total of 55 countries, 60% of them being outside of Western Europe and North America. We not only investigated how frequently various promotion criteria are mentioned, but also carried out a statistical analysis to infer structural commonalities and differences across policies. We find that quantitative assessment metrics remain popular, in agreement with other more geographically-restricted studies [5–9], but they are not omnipresent. We find notable differences between the Global North and the Global South as well as between institutional and national policies, but less so between research disciplines. In particular, the preference for bibliometric indicators is more marked in low- and middle-income countries. While we see some variation, many promotion policies assume that specific career paths that become normative rather than fully embracing ersity. In turn, this restricts opportunities for researchers. Our results challenge current practice and have strategic implications for researchers, research managers, and national governments.
Publisher: Oxford University Press (OUP)
Date: 11-05-2009
Publisher: American Astronomical Society
Date: 18-08-2017
Publisher: American Astronomical Society
Date: 07-2022
Abstract: We report the first unambiguous detection and mass measurement of an isolated stellar-mass black hole (BH). We used the Hubble Space Telescope (HST) to carry out precise astrometry of the source star of the long-duration ( t E ≃ 270 days), high-magnification microlensing event MOA-2011-BLG-191/OGLE-2011-BLG-0462 (hereafter designated as MOA-11-191/OGLE-11-462), in the direction of the Galactic bulge. HST imaging, conducted at eight epochs over an interval of 6 yr, reveals a clear relativistic astrometric deflection of the background star’s apparent position. Ground-based photometry of MOA-11-191/OGLE-11-462 shows a parallactic signature of the effect of Earth’s motion on the microlensing light curve. Combining the HST astrometry with the ground-based light curve and the derived parallax, we obtain a lens mass of 7.1 ± 1.3 M ⊙ and a distance of 1.58 ± 0.18 kpc. We show that the lens emits no detectable light, which, along with having a mass higher than is possible for a white dwarf or neutron star, confirms its BH nature. Our analysis also provides an absolute proper motion for the BH. The proper motion is offset from the mean motion of Galactic disk stars at similar distances by an amount corresponding to a transverse space velocity of ∼45 km s −1 , suggesting that the BH received a “natal kick” from its supernova explosion. Previous mass determinations for stellar-mass BHs have come from radial velocity measurements of Galactic X-ray binaries and from gravitational radiation emitted by merging BHs in binary systems in external galaxies. Our mass measurement is the first for an isolated stellar-mass BH using any technique.
Publisher: EDP Sciences
Date: 2005
DOI: 10.1051/EAS:2005047
Publisher: American Astronomical Society
Date: 02-05-2012
Publisher: American Association for the Advancement of Science (AAAS)
Date: 15-02-2008
Abstract: Searches for extrasolar planets have uncovered an astonishing ersity of planetary systems, yet the frequency of solar system analogs remains unknown. The gravitational microlensing planet search method is potentially sensitive to multiple-planet systems containing analogs of all the solar system planets except Mercury. We report the detection of a multiple-planet system with microlensing. We identify two planets with masses of ∼0.71 and ∼0.27 times the mass of Jupiter and orbital separations of ∼2.3 and ∼4.6 astronomical units orbiting a primary star of mass ∼0.50 solar mass at a distance of ∼1.5 kiloparsecs. This system resembles a scaled version of our solar system in that the mass ratio, separation ratio, and equilibrium temperatures of the planets are similar to those of Jupiter and Saturn. These planets could not have been detected with other techniques their discovery from only six confirmed microlensing planet detections suggests that solar system analogs may be common.
Publisher: Elsevier BV
Date: 03-2002
Publisher: American Astronomical Society
Date: 08-01-2013
Publisher: American Astronomical Society
Date: 24-03-2023
Abstract: We analyze the MOA-2020-BLG-208 gravitational microlensing event and present the discovery and characterization of a new planet, MOA-2020-BLG-208Lb, with an estimated sub-Saturn mass. With a mass ratio q = 3.17 − 0.26 + 0.28 × 10 − 4 , the planet lies near the peak of the mass-ratio function derived by the MOA collaboration and near the edge of expected s le sensitivity. For these estimates we provide results using two mass-law priors: one assuming that all stars have an equal planet-hosting probability, and the other assuming that planets are more likely to orbit around more massive stars. In the first scenario, we estimate that the lens system is likely to be a planet of mass m planet = 46 − 24 + 42 M ⊕ and a host star of mass M host = 0.43 − 0.23 + 0.39 M ⊙ , located at a distance D L = 7.49 − 1.13 + 0.99 kpc . For the second scenario, we estimate m planet = 69 − 34 + 37 M ⊕ , M host = 0.66 − 0.32 + 0.35 M ⊙ , and D L = 7.81 − 0.93 + 0.93 kpc . The planet has a projected separation as a fraction of the Einstein ring radius s = 1.3807 − 0.0018 + 0.0018 . As a cool sub-Saturn-mass planet, this planet adds to a growing collection of evidence for revised planetary formation models.
Publisher: American Astronomical Society
Date: 20-02-1999
DOI: 10.1086/306820
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Martin Dominik.