Journal ArticleDOI
Microlensing optical depth towards the Galactic bulge from MOA observations during 2000 with Difference Image Analysis
Takahiro Sumi,Fumio Abe,Ian A. Bond,R. J. Dodd,John B. Hearnshaw,Morihiro Honda,Mareki Honma,Yukitoshi Kan-ya,P. M. Kilmartin,Kimiaki Masuda,Y. Matsubara,Y. Muraki,T. Nakamura,Ryoichi Nishi,S. Noda,K. Ohnishi,O. K. L. Petterson,N. J. Rattenbury,M. Reid,To. Saito,Yoshihiko Saito,Hiroshi Sato,Masaki Sekiguchi,J. Skuljan,Denis J. Sullivan,M. Takeuti,P. J. Tristram,S. Wilkinson,Toshifumi Yanagisawa,P. C. M. Yock +29 more
TLDR
In this paper, the authors used Monte Carlo simulations to estimate the detection efficiency of microlensing event detection efficiency, where they constructed the I-band extinction map of their GB fields in order to find dereddened magnitudes.Abstract:
We analyze the data of the gravitational microlensing survey carried out by by the MOA group during 2000 towards the Galactic Bulge (GB). Our observations are designed to detect efficiently high magnification events with faint source stars and short timescale events, by increasing the the sampling rate up to 6 times per night and using Difference Image Analysis (DIA). We detect 28 microlensing candidates in 12 GB fields corresponding to 16 deg^2. We use Monte Carlo simulations to estimate our microlensing event detection efficiency, where we construct the I-band extinction map of our GB fields in order to find dereddened magnitudes. We find a systematic bias and large uncertainty in the measured value of the timescale $t_{\rm Eout}$ in our simulations. They are associated with blending and unresolved sources, and are allowed for in our measurements. We compute an optical depth tau = 2.59_{-0.64}^{+0.84} \times 10^{-6} towards the GB for events with timescales 0.3 10). These events are useful for studies of extra-solar planets.read more
Citations
More filters
Journal ArticleDOI
Unbound or distant planetary mass population detected by gravitational microlensing
Takahiro Sumi,Kisaku Kamiya,David P. Bennett,Ian A. Bond,Fumio Abe,C. S. Botzler,Akihiko Fukui,K. Furusawa,John B. Hearnshaw,Yoshitaka Itow,P. M. Kilmartin,A. V. Korpela,W. Lin,C. H. Ling,Kimiaki Masuda,Yutaka Matsubara,N. Miyake,M. Motomura,Yasushi Muraki,M. Nagaya,Shota Nakamura,Kouji Ohnishi,Teppei Okumura,Y. C. Perrott,Nicholas J. Rattenbury,To. Saito,T. K. Sako,Denis J. Sullivan,Winston L. Sweatman,P. J. Tristram,P. C. M. Yock,Andrzej Udalski,Michał K. Szymański,M. Kubiak,Grzegorz Pietrzyński,Radosław Poleski,Igor Soszyński,Łukasz Wyrzykowski,K. Ulaczyk +38 more
TL;DR: The discovery of a population of unbound or distant Jupiter-mass objects is reported, which are almost twice as common as main-sequence stars, based on two years of gravitational microlensing survey observations towards the Galactic Bulge.
Journal ArticleDOI
Quantifying quasar variability as part of a general approach to classifying continuously varying sources
Szymon Kozłowski,Christopher S. Kochanek,Andrzej Udalski,Łukasz Wyrzykowski,Łukasz Wyrzykowski,Igor Soszyński,Michał K. Szymański,M. Kubiak,Grzegorz Pietrzyński,Grzegorz Pietrzyński,O. Szewczyk,O. Szewczyk,Krzysztof Ulaczyk,Radosław Poleski +13 more
TL;DR: In this paper, a fast method for modeling and classifying non-periodic continuously varying sources (quasars, aperiodic stellar variability) is presented, where the location of common variability classes in the parameter space of the model is discussed.
Journal ArticleDOI
Improved Estimates of the Milky Way’s Stellar Mass and Star Formation Rate From Hierarchical Bayesian Meta-analysis
TL;DR: In this article, a hierarchical Bayesian (HB) statistical method was proposed to account for the possibility that any value may be incorrect or have underestimated errors, which is robust to a wide variety of assumptions about the nature of problems in individual measurements or errors.
Journal ArticleDOI
A Low-Mass Planet with a Possible Sub-Stellar-Mass Host in Microlensing Event MOA-2007-BLG-192
David P. Bennett,Ian A. Bond,Andrzej Udalski,Takahiro Sumi,Fumio Abe,Akihiko Fukui,K. Furusawa,John B. Hearnshaw,S. Holderness,Yoshitaka Itow,Kisaku Kamiya,A. V. Korpela,P. M. Kilmartin,W. Lin,C. H. Ling,Kimiaki Masuda,Yutaka Matsubara,N. Miyake,Yasushi Muraki,M. Nagaya,Teppei Okumura,Kouji Ohnishi,Y. C. Perrott,Nicholas J. Rattenbury,Takashi Sako,To. Saito,Susumu Sato,L. Skuljan,Denis J. Sullivan,Winston L. Sweatman,P. J. Tristram,Philip Yock,M. Kubiak,Michał K. Szymański,Grzegorz Pietrzyński,Grzegorz Pietrzyński,Igor Soszyński,O. Szewczyk,O. Szewczyk,Łukasz Wyrzykowski,Łukasz Wyrzykowski,Krzysztof Ulaczyk,V. Batista,J. P. Beaulieu,S. Brillant,Arnaud Cassan,P. Fouque,Pierre Kervella,D. Kubas,J. B. Marquette +49 more
TL;DR: In this paper, the authors reported the detection of an extrasolar planet of mass ratio q~2×10-4 in microlensing event MOA-2007-BLG-192.
Journal ArticleDOI
A COLD NEPTUNE-MASS PLANET OGLE-2007-BLG-368Lb: COLD NEPTUNES ARE COMMON
Takahiro Sumi,D. P. Bennett,Ian A. Bond,Andrzej Udalski,V. Batista,Martin Dominik,Martin Dominik,P. Fouqué,D. Kubas,Andrew Gould,Bruce Macintosh,K. H. Cook,Subo Dong,L. Skuljan,Arnaud Cassan,Fumio Abe,C. S. Botzler,Akihiko Fukui,K. Furusawa,John B. Hearnshaw,Yoshitaka Itow,Kisaku Kamiya,P. M. Kilmartin,A. V. Korpela,W. Lin,C. H. Ling,Kimiaki Masuda,Yutaka Matsubara,N. Miyake,Yasushi Muraki,M. Nagaya,Takahiro Nagayama,Kouji Ohnishi,Teppei Okumura,Y. C. Perrott,Nicholas J. Rattenbury,To. Saito,Takashi Sako,D. J. Sullivan,Winston L. Sweatman,P. J. Tristram,Philip Yock,J. P. Beaulieu,Andrew A. Cole,Ch. Coutures,M. F. Duran,J. G. Greenhill,Francisco Jablonski,U. Marboeuf,Eder Martioli,Ettore Pedretti,Ondřej Pejcha,Patricio Rojo,Michael D. Albrow,S. Brillant,M. F. Bode,D. M. Bramich,Martin Burgdorf,Martin Burgdorf,J. A. R. Caldwell,H. Calitz,E. Corrales,S. Dieters,S. Dieters,D. Dominis Prester,J. Donatowicz,K. M. Hill,K. M. Hill,M. Hoffman,Keith Horne,U. G. Jørgensen,N. Kains,Stephen R. Kane,J. B. Marquette,R. M. Martin,P. J. Meintjes,J. W. Menzies,K. R. Pollard,Kailash C. Sahu,Colin Snodgrass,Iain A. Steele,Rachel Street,Yiannis Tsapras,Joachim Wambsganss,Andrew Williams,M. Zub,Michał K. Szymański,M. Kubiak,Grzegorz Pietrzyński,Grzegorz Pietrzyński,Igor Soszyński,O. Szewczyk,Łukasz Wyrzykowski,Krzysztof Ulaczyk,William H. Allen,G. W. Christie,Darren L. DePoy,B. S. Gaudi,C. Han,J. Janczak,C.-U. Lee,Jennie McCormick,F. Mallia,B. Monard,Tim Natusch,Byeong-Gon Park,Richard W. Pogge,R. Santallo +107 more
TL;DR: The OGLE-2007-BLG-368Lb with a planet-star mass ratio of q = [9.5 ± 2.1] × 10^(-5] via gravitational microlensing was discovered in real-time thanks to the high cadence of the Microlensing Observations in Astrophysics survey and intensive followup observations.
References
More filters
Journal ArticleDOI
Gravitational microlensing by the galactic halo
TL;DR: A simple model of microlensing by massive objects that might be present in the halo of the Galaxy is presented in this article, where it is shown that in any nearby galaxy one star out of a million is strongly microlensed by a "dark" object located in the Galactic halo, if the hale is made up of objects more massive than about 10 to the -8th solar mass.
Journal ArticleDOI
A Method for Optimal Image Subtraction
TL;DR: In this paper, a new method was proposed for image subtraction using a simple least-squares analysis using all the pixels of both images, and also showed that it is possible to fit the differential background variation at the same time.
Journal ArticleDOI
Image subtraction using a space-varying kernel
TL;DR: In this paper, the authors generalize the theory to the case of space-varying kernels and show that the CPU cost required for this new extension of the method is almost the same as for fitting a constant kernel solution.
Journal ArticleDOI
DOPHOT, a CCD photometry program: Description and tests
TL;DR: In this article, a point-spread function (PSF) fitting photometry program, DOPHOT, is described and the quality of the resulting photometry is assessed via reductions of an 'artificial' globular cluster generated from a list of stars with known magnitudes and colors.
Journal ArticleDOI
Morphology, near infrared luminosity, and mass of the galactic bulge from Cobe dirbe observations
E. Dwek,R. G. Arendt,M. G. Hauser,T. Kelsall,Carey M. Lisse,S. H. Moseley,Robert F. Silverberg,T. J. Sodroski,Janet Weiland +8 more
TL;DR: In this paper, the authors used triaxial analytical functions to represent the volume emissivity of the source and confirmed the bar-like nature of the bulge and showed that triaxially Gaussian-type functions provide a better fit to the data than other classes of functions, including an axisymmetric spheroid.
Related Papers (5)
Real-time difference imaging analysis of moa galactic bulge observations during 2000
Ian A. Bond,Ian A. Bond,Fumio Abe,R. J. Dodd,R. J. Dodd,R. J. Dodd,John B. Hearnshaw,Morihiro Honda,Jun Jugaku,P. M. Kilmartin,P. M. Kilmartin,A. Marles,Kimiaki Masuda,Yutaka Matsubara,Yasushi Muraki,Takashi Nakamura,G. Nankivell,S. Noda,C. Noguchi,Kouji Ohnishi,Nicholas J. Rattenbury,M. Reid,To. Saito,Hiroshi Sato,Maki Sekiguchi,J. Skuljan,D. J. Sullivan,Takahiro Sumi,Mine Takeuti,Yoshiyuki Watase,S. Wilkinson,R. Yamada,T. Yanagisawa,Philip Yock +33 more
Reddening and extinction toward the galactic bulge from ogle-iii: the inner milky way's rv ∼ 2.5 extinction curve*
David M. Nataf,David M. Nataf,Andrew Gould,Pascal Fouqué,Pascal Fouqué,Oscar A. Gonzalez,Jennifer A. Johnson,Jan Skowron,Andrzej Udalski,Michał K. Szymański,M. Kubiak,Grzegorz Pietrzyński,Grzegorz Pietrzyński,Igor Soszyński,Krzysztof Ulaczyk,Łukasz Wyrzykowski,Łukasz Wyrzykowski,Radosław Poleski +17 more
Unbound or distant planetary mass population detected by gravitational microlensing
Takahiro Sumi,Kisaku Kamiya,David P. Bennett,Ian A. Bond,Fumio Abe,C. S. Botzler,Akihiko Fukui,K. Furusawa,John B. Hearnshaw,Yoshitaka Itow,P. M. Kilmartin,A. V. Korpela,W. Lin,C. H. Ling,Kimiaki Masuda,Yutaka Matsubara,N. Miyake,M. Motomura,Yasushi Muraki,M. Nagaya,Shota Nakamura,Kouji Ohnishi,Teppei Okumura,Y. C. Perrott,Nicholas J. Rattenbury,To. Saito,T. K. Sako,Denis J. Sullivan,Winston L. Sweatman,P. J. Tristram,P. C. M. Yock,Andrzej Udalski,Michał K. Szymański,M. Kubiak,Grzegorz Pietrzyński,Radosław Poleski,Igor Soszyński,Łukasz Wyrzykowski,K. Ulaczyk +38 more