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Your search keyword '"De Almeida, L. Andrade"' showing total 4 results
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4 results on '"De Almeida, L. Andrade"'

1. Red noise versus planetary interpretations in the microlensing event OGLE-2013-BLG-446

Author

Bachelet, E., Bramich, D. M., Han, C., Greenhill, J., Street, R. A., Gould, A., Ago, G. D, AlSubai, K., Dominik, M., Jaimes, R. Figuera, Horne, K., Hundertmark, M., Kains, N., Snodgrass, C., Steele, I. A., Tsapras, Y., Albrow, M. D., Batista, V., Beaulieu, J. -P., Bennett, D. P., Brillant, S., Caldwell, J. A. R., Cassan, A., Cole, A., Coutures, C., Dieters, S., Prester, D. Dominis, Donatowicz, J., Fouque, P., Hill, K., Marquette, J. -B., Menzies, J., Pere, C., Ranc, C., Wambsganss, J., Warren, D., de Almeida, L. Andrade, Choi, J. -Y., DePoy, D. L., Dong, Subo, Hung, L. -W., Hwang, K. H., Jablonski, F., Jung, Y. K., Kaspi, S., Klein, N., Lee, C. -U., Maoz, D., Munoz, J. A., Nataf, D., Park, H., Pogge, R. W., Polishook, D., Shin, I. -G., Shporer, A., Abe, J. C. Yee F., Bhattacharya, A., Bond, I. A., Botzler, C. S., Freeman, M., Fukui, A., Itow, Y., Koshimoto, N., Ling, C. H., Masuda, K., Matsubara, Y., Muraki, Y., Ohnishi, K., Philpott, L. C., Rattenbury, N., Saito, To., Sullivan, D. J., Sumi, T., Suzuki, D., Tristram, J., Yonehara, A., Bozza, V., Novati, S. Calchi, Ciceri, S., Galianni, P., Gu, S. H., Harpsoe, K., Hinse, T. C., Jorgensen, U. G., Juncher, D., Korhonen, H., Mancini, L., Melchiorre, C., Popovas, A., Postiglione, A., Rabus, M., Rahvar, S., Schmidt, R. W., Scarpetta, G., Skottfelt, J., Southworth, John, Stabile, An., Surdej, J., Wang, X. -B., and Wertz, O.

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

For all exoplanet candidates, the reliability of a claimed detection needs to be assessed through a careful study of systematic errors in the data to minimize the false positives rate. We present a method to investigate such systematics in microlensing datasets using the microlensing event OGLE-2013-BLG-0446 as a case study. The event was observed from multiple sites around the world and its high magnification (A_{max} \sim 3000) allowed us to investigate the effects of terrestrial and annual parallax. Real-time modeling of the event while it was still ongoing suggested the presence of an extremely low-mass companion (\sim 3M_\oplus ) to the lensing star, leading to substantial follow-up coverage of the light curve. We test and compare different models for the light curve and conclude that the data do not favour the planetary interpretation when systematic errors are taken into account., Comment: accepted ApJ 2015

Published
2015
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2. Interpretation of a Short-Term Anomaly in the Gravitational Microlensing Event MOA-2012-BLG-486

Author

Hwang, K. -H., Choi, J. -Y., Bond, I. A., Sumi, T., Han, C., Gaudi, B. S., Gould, A., Bozza, V., Beaulieu, J. -P., Tsapras, Y., Abe, F., Bennett, D. P., Botzler, C. S., Chote, P., Freeman, M., Fukui, A., Fukunaga, D., Harris, P., Itow, Y., Koshimoto, N., Ling, C. H., Masuda, K., Matsubara, Y., Muraki, Y., Namba, S., Ohnishi, K., Rattenbury, N. J., Saito, To., Sullivan, D. J., Sweatman, W. L., Suzuki, D., Tristram, P. J., Wada, K., Yamai, N., Yock, P. C. M., Yonehara, A., de Almeida, L. Andrade, DePoy, D. L., Dong, Subo, Jablonski, F., Jung, Y. K., Kavka, A., Lee, C. -U., Park, H., Pogge, R. W., Shin, I. -G., Yee, J. C., Albrow, M. D., Bachelet, E., Batista, V., Brillant, S., Caldwell, J. A. R., Cassan, A., Cole, A., Corrales, E., Coutures, Ch., Dieters, S., Prester, D. Dominis, Donatowicz, J., Fouqué, P., Greenhill, J., Jørgensen, U. G., Kane, S. R., Kubas, D., Marquette, J. -B., Martin, R., Meintjes, P., Menzies, J., Pollard, K. R., Williams, A., Wouters, D., Bramich, D. M., Dominik, M., Horne, K., Browne, P., Hundertmark, M., Ipatov, S., Kains, N., Snodgrass, C., Steele, I. A., and Street, R. A.

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

A planetary microlensing signal is generally characterized by a short-term perturbation to the standard single lensing light curve. A subset of binary-source events can produce perturbations that mimic planetary signals, thereby introducing an ambiguity between the planetary and binary-source interpretations. In this paper, we present analysis of the microlensing event MOA-2012-BLG-486, for which the light curve exhibits a short-lived perturbation. Routine modeling not considering data taken in different passbands yields a best-fit planetary model that is slightly preferred over the best-fit binary-source model. However, when allowed for a change in the color during the perturbation, we find that the binary-source model yields a significantly better fit and thus the degeneracy is clearly resolved. This event not only signifies the importance of considering various interpretations of short-term anomalies, but also demonstrates the importance of multi-band data for checking the possibility of false-positive planetary signals., Comment: 5 pages, 4 figures and ApJ submitted

Published
2013
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3. MOA-2010-BLG-073L: An M-Dwarf with a Substellar Companion at the Planet/Brown Dwarf Boundary

Author

Street, R. A., Choi, J. -Y., Tsapras, Y., Han, C., Furusawa, K., Hundertmark, M., Gould, A., Sumi, T., Bond, I. A., Wouters, D., Zellem, R., Udalski, A., Snodgrass, C., Horne, K., Dominik, M., Browne, P., Kains, N., Bramich, D. M., Bajek, D., Steele, I. A., Ipatov, S., Abe, F., Bennett, D. P., Botzler, C. S., Chote, P., Freeman, M., Fukui, A., Harris, P., Itow, Y., Ling, C. H., Masuda, K., Matsubara, Y., Miyake, N., Muraki, Y., Nagayama, T., Nishimaya, S., Ohnishi, K., Rattenbury, N., Saito, To., Sullivan, D. J., Suzuki, D., Sweatman, W. L., Tristram, P. J., Wada, K., Yock, P. C. M., Szymanski, M. K., Kubiak, M., Pietrzynski, G., Soszynski, I., Poleski, R., Ulaczyk, K., Wyrzykowski, L., Yee, J., Dong, S., Shin, I. -G., Lee, C. -U., Skowron, J., De Almeida, L. Andrade, DePoy, D. L., Gaudi, B. S., Hung, L. -W., Jablonski, F., Kaspi, S., Klein, N., Hwang, K. -H., Koo, J. -R., Maoz, D., Munoz, J. A., Pogge, R. W., Polishhook, D., Shporer, A., McCormick, J., Christie, G., Natusch, T., Allen, B., Drummond, J., Moorhouse, D., Thornley, G., Knowler, M., Bos, M., Bolt, G., Beaulieu, J. -P., Albrow, M. D., Batista, V., Brillant, S., Caldwell, J. A. R., Cassan, A., Cole, A., Corrales, E., Coutures, Ch., Dieters, S., Prester, D. Dominis, Donatowicz, J., Fouque, P., Bachelet, E., Greenhill, J., Kane, S. R., Kubas, D., Marquette, J. -B., Martin, R., Menzies, J., Pollard, K. R., Sahu, K. C., Wambsganss, J., Williams, A., Zub, M., Alsubai, K. A., Bozza, V., Burgdorf, M. J., Novati, S. Calchi, Dodds, P., Dreizler, S., Finet, F., Gerner, T., Hardis, S., Harpsoe, K., Hessman, F., Hinse, T. C., Jorgensen, U. G., Kerins, E., Liebig, C., Mancini, L., Mathiasen, M., Penny, M. T., Proft, S., Rahvar, S., Ricci, D., Scarpetta, G., Schafer, S., Schonebeck, F., Southworth, J., and Surdej, J.

Subjects
Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract

We present an analysis of the anomalous microlensing event, MOA-2010-BLG-073, announced by the Microlensing Observations in Astrophysics survey on 2010-03-18. This event was remarkable because the source was previously known to be photometrically variable. Analyzing the pre-event source lightcurve, we demonstrate that it is an irregular variable over time scales >200d. Its dereddened color, $(V-I)_{S,0}$, is 1.221$\pm$0.051mag and from our lens model we derive a source radius of 14.7$\pm$1.3 $R_{\odot}$, suggesting that it is a red giant star. We initially explored a number of purely microlensing models for the event but found a residual gradient in the data taken prior to and after the event. This is likely to be due to the variability of the source rather than part of the lensing event, so we incorporated a slope parameter in our model in order to derive the true parameters of the lensing system. We find that the lensing system has a mass ratio of q=0.0654$\pm$0.0006. The Einstein crossing time of the event, $T_{\rm{E}}=44.3$\pm$0.1d, was sufficiently long that the lightcurve exhibited parallax effects. In addition, the source trajectory relative to the large caustic structure allowed the orbital motion of the lens system to be detected. Combining the parallax with the Einstein radius, we were able to derive the distance to the lens, $D_L$=2.8$\pm$0.4kpc, and the masses of the lensing objects. The primary of the lens is an M-dwarf with $M_{L,p}$=0.16$\pm0.03M_{\odot}$ while the companion has $M_{L,s}$=11.0$\pm2.0M_{\rm{J}}$ putting it in the boundary zone between planets and brown dwarfs., Comment: 24 pages, 8 figures, best viewed in colour, accepted by ApJ

Published
2012
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4. MOA-2010-BLG-477Lb: constraining the mass of a microlensing planet from microlensing parallax, orbital motion and detection of blended light

Author

Bachelet, E., Shin, I. -G., Han, C., Fouqué, P., Gould, A., Menzies, J. W., Beaulieu, J. -P., Bennett, D. P., Bond, I. A., Dong, Subo, Heyrovský, D., Marquette, J. B., Marshall, J., Skowron, J., Street, R. A., Sumi, T., Udalski, A., Abe, L., Agabi, K., Albrow, M. D., Allen, W., Bertin, E., Bos, M., Bramich, D. M., Chavez, J., Christie, G. W., Cole, A. A., Crouzet, N., Dieters, S., Dominik, M., Drummond, J., Greenhill, J., Guillot, T., Henderson, C. B., Hessman, F. V., Horne, K., Hundertmark, M., Johnson, J. A., Jørgensen, U. G., Kandori, R., Liebig, C., Mékarnia, D., McCormick, J., Moorhouse, D., Nagayama, T., Nataf, D., Natusch, T., Nishiyama, S., Rivet, J. -P., Sahu, K. C., Shvartzvald, Y., Thornley, G., Tomczak, A. R., Tsapras, Y., Yee, J. C., Batista, V., Bennett, C. S., Brillant, S., Caldwell, J. A. R., Cassan, A., Corrales, E., Coutures, C., Prester, D. Dominis, Donatowicz, J., Kubas, D., Martin, R., Williams, A., Zub, M., de Almeida, L. Andrade, DePoy, D. L., Gaudi, B. S., Hung, L. -W., Jablonski, F., Kaspi, S., Klein, N., Lee, C. -U., Lee, Y., Koo, J. -R., Maoz, D., Muñoz, J. A., Pogge, R. W., Polishook, D., Shporer, A., Abe, F., Botzler, C. S., Chote, P., Freeman, M., Fukui, A., Furusawa, K., Harris, P., Itow, Y., Kobara, S., Ling, C. H., Masuda, K., Matsubara, Y., Miyake, N., Ohmori, K., Ohnishi, K., Rattenbury, N. J., Saito, To., Sullivan, D. J., 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., Kains, N., Snodgrass, C., Steele, I. A., Alsubai, K. A., Bozza, V., Browne, P., Burgdorf, M. J., Novati, S. Calchi, Dodds, P., Dreizler, S., Finet, F., Gerner, T., Hardis, S., Harpsøe, K., Hinse, T. C., Kerins, E., Mancini, L., Mathiasen, M., Penny, M. T., Proft, S., Rahvar, S., Ricci, D., Scarpetta, G., Schäfer, S., Schönebeck, F., Southworth, J., Surdej, J., and Wambsganss, J.

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

Microlensing detections of cool planets are important for the construction of an unbiased sample to estimate the frequency of planets beyond the snow line, which is where giant planets are thought to form according to the core accretion theory of planet formation. In this paper, we report the discovery of a giant planet detected from the analysis of the light curve of a high-magnification microlensing event MOA-2010-BLG-477. The measured planet-star mass ratio is $q=(2.181\pm0.004)\times 10^{-3}$ and the projected separation is $s=1.1228\pm0.0006$ in units of the Einstein radius. The angular Einstein radius is unusually large $\theta_{\rm E}=1.38\pm 0.11$ mas. Combining this measurement with constraints on the "microlens parallax" and the lens flux, we can only limit the host mass to the range $0.13

Published
2012
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