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Start Over Author "D. J. Sullivan" Journal monthly notices of the royal astronomical society
6 results on '"D. J. Sullivan"'

1. OGLE-2017-BLG-1186: first application of asteroseismology and Gaussian processes to microlensing

Author

S-S Li, W Zang, A Udalski, Y Shvartzvald, D Huber, C-U Lee, T Sumi, A Gould, S Mao, P Fouqué, T Wang, S Dong, U G Jørgensen, A Cole, P Mróz, M K Szymański, J Skowron, R Poleski, I Soszyński, P Pietrukowicz, S Kozłowski, K Ulaczyk, K A Rybicki, P Iwanek, J C Yee, S Calchi Novati, C A Beichman, G Bryden, S Carey, B S Gaudi, C B Henderson, W Zhu, M D Albrow, S-J Chung, C Han, K-H Hwang, Y K Jung, Y-H Ryu, I-G Shin, S-M Cha, D-J Kim, H-W Kim, S-L Kim, D-J Lee, Y Lee, B-G Park, R W Pogge, I A Bond, F Abe, R Barry, D P Bennett, A Bhattacharya, M Donachie, A Fukui, Y Hirao, Y Itow, I Kondo, N Koshimoto, M C A Li, Y Matsubara, Y Muraki, S Miyazaki, M Nagakane, C Ranc, N J Rattenbury, H Suematsu, D J Sullivan, D Suzuki, P J Tristram, A Yonehara, G Christie, J Drummond, J Green, S Hennerley, T Natusch, I Porritt, E Bachelet, D Maoz, R A Street, Y Tsapras, V Bozza, M Dominik, M Hundertmark, N Peixinho, S Sajadian, M J Burgdorf, D F Evans, R Figuera Jaimes, Y I Fujii, L K Haikala, C Helling, T Henning, T C Hinse, L Mancini, P Longa-Peña, S Rahvar, M Rabus, J Skottfelt, C Snodgrass, J Southworth, E Unda-Sanzana, C von Essen, J-P Beaulieu, J Blackman, and K Hill

Published
2019
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2. An analysis of binary microlensing event OGLE-2015-BLG-0060

Author

Y Tsapras, A Cassan, C Ranc, E Bachelet, R Street, A Udalski, M Hundertmark, V Bozza, J P Beaulieu, J B Marquette, E Euteneuer, D M Bramich, M Dominik, R Figuera Jaimes, K Horne, S Mao, J Menzies, R Schmidt, C Snodgrass, I A Steele, J Wambsganss, P Mróz, M K Szymański, I Soszyński, J Skowron, P Pietrukowicz, S Kozłowski, R Poleski, K Ulaczyk, M Pawlak, U G Jørgensen, J Skottfelt, A Popovas, S Ciceri, H Korhonen, M Kuffmeier, D F Evans, N Peixinho, T C Hinse, M J Burgdorf, J Southworth, R Tronsgaard, E Kerins, M I Andersen, S Rahvar, Y Wang, O Wertz, M Rabus, S Calchi Novati, G D’Ago, G Scarpetta, L Mancini, F Abe, Y Asakura, D P Bennett, A Bhattacharya, M Donachie, P Evans, A Fukui, Y Hirao, Y Itow, K Kawasaki, N Koshimoto, M C A Li, C H Ling, K Masuda, Y Matsubara, Y Muraki, S Miyazaki, M Nagakane, K Ohnishi, N Rattenbury, To Saito, A Sharan, H Shibai, D J Sullivan, T Sumi, D Suzuki, P J Tristram, T Yamada, A Yonehara, G D'Ago, and T o Saito

Published
2019
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3. OGLE-2017-BLG-1186: First Application of Asteroseismology and Gaussian Processes to microlensing

Author

S.-S. Li, A. Udalski, Y. Shvartzvald, D. Huber, C.-U. Lee, T. Sumi, A. Gould, S. Mao, P. Fouqu´e, S. Dong, U. G. Jørgensen, A. Cole, P. Mr´oz, M. K. Szyma´nski, J. Skowron, R. Poleski, I. Soszy´nski, P. Pietrukowicz, S. Kozłowski, K. Ulaczyk, K. A. Rybicki, P. Iwanek, J. C. Yee, S. Calchi Novati, C. A. Beichman, G. Bryden, S. Carey, B. S. Gaudi, C. B. Henderson, W. Zhu, M. D. Albrow, S.-J. Chung, C. Han, K.-H. Hwang, Y. K. Jung, Y.-H. Ryu, I.-G. Shin, S.-M. Cha, D.-J. Kim, H.-W. Kim, S.-L. Kim, D.-J. Lee, Y. Lee, B.-G. Park, R. W. Pogge, I. A. Bond, F. Abe, R Barry, D P Bennett, A Bhattacharya, M. Donachie, A. Fukui, Y. Hirao, Y. Itow, I. Kondo, N. Koshimoto, M. C. A. Li, Y. Matsubara, Y. Muraki, S. Miyazaki, M. Nagakane, C Ranc, N. J. Rattenbury, H. Suematsu, D. J. Sullivan, D. Suzuki, P. J. Tristram, A. Yonehara3, G. Christie, J. Drummond, J. Green, S. Hennerley, T. Natusch, I. Porritt, E. Bachelet, D. Maoz, R. A. Street, Y. Tsapras, V. Bozza, M. Dominik, M. Hundertmark, N. Peixinho, S. Sajadian, M. J. Burgdorf, D. F. Evans, R. Figuera Jaimes, Y. I. Fujii, L. K. Haikala, C. Helling, T. Henning, T. C. Hinse, L. Mancini, P. Longa-Pe˜na, S. Rahvar, M. Rabus, J. Skottfelt, C. Snodgrass, J. Southworth, E. Unda-Sanzana, C. von Essen, J.-P. Beaulieu, J. Blackman, and K. Hill

Subjects
Astrophysics
Abstract

We present the analysis of the event OGLE-2017-BLG-1186 from the 2017 Spitzer microlensing campaign. 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 timescale of ∼9 d. The asteroseismic analysis also provides us source properties including the source angular size (∼27 μas) 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 χ(exp 2) 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 Mʘ brown dwarf at distance ∼9.0 kpc, or a ∼0.073 Mʘ ultracool dwarf at distance ∼9.8 kpc. Combining the estimated lens properties with a Bayesian analysis using a Galactic model, we find a ∼ 35 per cent probability for the lens to be a bulge object and ∼ 65 per cent to be a background disc object.

Published
2019
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4. An analysis of binary microlensing event OGLE-2015-BLG-0060

Author

Y. Tsapras, A. Cassan, Clement Ranc, E. Bachelet, R. Street, A. Udalski, M. Hundertmark, V. Bozza, J. P. Beaulieu, J. B Marquette, E. Euteneuer, D. M. Bramich, M. Dominik, R. Figuera Jaimes, K. Horne, S. Mao, J. Menzies, R. Schmidt, C. Snodgrass, I. A. Steele, J. Wambsganss, P. Mr´oz, M. K. Szyma´nski, I. Soszy´nski, J. Skowron, P. Pietrukowicz, S. Kozlowski, R. Poleski, K. Ulaczyk, M. Pawlak, U. G. Jorgensen, J. Skottfelt, A. Popovas, S. Ciceri, H. Korhonen, M. Kuffmeier, D.F. Evans, N. Peixinho, T. C. Hinse, M. J. Burgdorf, J. Southworth, R. Tronsgaard, E. Kerins, M. I. Andersen, S. Rahvar, Y. Wang, O. Wertz, M. Rabus, S. Calchi Novati, G. D’Ago, G. Scarpetta, L. Mancini, F. Abe, Y. Asakura, D P Bennett, A Bhattacharya, M. Donachie, P. Evans, A. Fukui, Y. Hirao, Y. Itow, K. Kawasaki, N. Koshimoto, M. C. A. Li, C. H. Ling, K. Masuda, Y. Matsubara, Y. Muraki, S. Miyazaki, M. Nagakane, K. Ohnishi, N. Rattenbury, To. Saito, A. Sharan, H. Shibai, D. J. Sullivan, T. Sumi, D Suzuki, P. J. Tristram, T. Yamada, and A. Yonehara

Subjects
Astronomy
Abstract

We present the analysis of stellar binary microlensing event OGLE-2015-BLG-0060 based on observations obtained from 13 different telescopes. Intensive coverage of the anomalous parts of the light curve was achieved by automated follow-up observations from the robotic telescopes of the Las Cumbres Observatory. We show that, for the first time, all main features of an anomalous microlensing event are well covered by follow-up data, allowing us to estimate the physical parameters of the lens. The strong detection of second-order effects in the event light curve necessitates the inclusion of longer-baseline survey data in order to constrain the parallax vector. We find that the event was most likely caused by a stellar binary-lens with masses M ͙(1) = 0.87 ± 0.12M(☉) and M ͙(2)= 0.77 ± 0.11M(☉). The distance to the lensing system is 6.41 ± 0.14 kpc and the projected separation between the two components is 13.85 ± 0.16 au. Alternative interpretations are also considered.

Published
2019
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5. Whole Earth Telescope observations of the subdwarf B star KPD 1930+2752: a rich, short-period pulsator in a close binary

Author

Chris Cameron, Ömür Çakırlı, R. Avila, G. Stachowski, C. Akan, Y. M. Lipkin, S. L. Harms, Z. Csubry, Jaymie M. Matthews, M. Vuckovic, D. W. Winget, S. McDaniel, D. Zsuffa, Róbert Szabó, J. Bodnarik, R. Janulis, J. L. Provencal, M. Paparó, X.-J. Jian, M. Chevreton, Roy Ostensen, R. Pretorius, Michael D. Reed, J.-P. Gou, Fergal Mullally, Hong Wu, Reed Riddle, W. Ogloza, B. Berkey, H.-C. Lin, Wen Ping Chen, Philippe M. Binder, Pawel Moskalik, A. F. M. Costa, J.-E. Solheim, G. Vauclair, Roberto Silvotti, Ivan Bruni, R. Crowe, Kazuhiro Sekiguchi, S. G. Stewart, D. Terry, E. M. Leibowitz, C.-W. Chen, A. C. Quint, Zong-Li Liu, M. A. Morris, S. L. Kim, D. J. Sullivan, J. R. Eggen, S. Marinoni, S. Poindexter, Andrzej S. Baran, H. Pablo, D. W. Kurtz, Stanisław Zoła, N. Dolez, Steven D. Kawaler, Souza Oliveira Kepler, A.-Y. Zhou, and D. Bolton

Subjects
Physics, Subdwarf B star, 010308 nuclear & particles physics, Phase (waves), White dwarf, Binary number, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Subdwarf, law.invention, Telescope, Amplitude, 13. Climate action, Space and Planetary Science, law, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Multiplet
Abstract

KPD 1930+2752 is a short-period pulsating subdwarf B (sdB) star. It is also an ellipsoidal variable with a known binary period just over two hours. The companion is most likely a white dwarf and the total mass of the system is close to the Chandresakhar limit. In this paper we report the results of Whole Earth Telescope (WET) photometric observations during 2003 and a smaller multisite campaign from 2002. From 355 hours of WET data, we detect 68 pulsation frequencies and suggest an additional 13 frequencies within a crowded and complex temporal spectrum between 3065 and 6343 $\mu$Hz (periods between 326 and 157 s). We examine pulsation properties including phase and amplitude stability in an attempt to understand the nature of the pulsation mechanism. We examine a stochastic mechanism by comparing amplitude variations with simulated stochastic data. We also use the binary nature of KPD 1930+2752 for identifying pulsation modes via multiplet structure and a tidally-induced pulsation geometry. Our results indicate a complicated pulsation structure that includes short-period ($\approx 16$ h) amplitude variability, rotationally split modes, tidally-induced modes, and some pulsations which are geometrically limited on the sdB star.

Published
2011
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6. The discovery of a persistent quasi-periodic oscillation in the intermediate polar TX Col

Author

Brian Warner, Jennie McCormick, F. Velhuis, Robert Rea, David A. H. Buckley, Patrick A. Woudt, Greg Bolt, V. S. Dhillon, N. Mhlahlo, D. J. Sullivan, and Stephen Potter

Subjects
Physics, Quasi-periodic oscillation, Accretion (meteorology), Astrophysics::High Energy Astrophysical Phenomena, Magnetosphere, Boundary (topology), Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Photometry (astronomy), Intermediate polar, Space and Planetary Science, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Variation (astronomy), Astrophysics::Galaxy Astrophysics, Spin-½
Abstract

We report on the detection of an ~5900 s quasi-periodic variation in the extensive photometry of TX Col spanning 12 years. We discuss five different models to explain this period. We favour a mechanism where the quasi-periodic variation results from the beating of the Keplerian frequency of the `blobs' orbiting in the outer accretion disc with the spin frequency, and from modulated accretion of these `blobs' taking place in a shocked region near the disc/magnetosphere boundary.

Published
2007
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