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Start Over Author "Novati SC" Topic astrophysics::galaxy astrophysics
8 results on '"Novati SC"'

1. Precision measurement of a brown dwarf mass in a binary system in the microlensing event OGLE-2019-BLG-0033/MOA-2019-BLG-035

Author

Herald, A, Udalski, A, Bozza, V, Rota, P, Bond, IA, Yee, JC, Sajadian, S, Mroz, P, Poleski, R, Skowron, J, Szymanski, MK, Soszynski, I, Pietrukowicz, P, Kozlowski, S, Ulaczyk, K, Rybicki, KA, Iwanek, P, Wrona, M, Gromadzki, M, Abe, F, Barry, R, Bennett, DP, Bhattacharya, A, Fukui, A, Fujii, H, Hirao, Y, Itow, Y, Kirikawa, R, Kondo, I, Koshimoto, N, Matsubara, Y, Matsumoto, S, Miyazaki, S, Muraki, Y, Olmschenk, G, Ranc, C, Okamura, A, Rattenbury, NJ, Satoh, Y, Sumi, T, Suzuki, D, Silva, SI, Toda, T, Tristram, PJ, Vandorou, A, Yama, H, Beichman, CA, Bryden, G, Novati, SC, Carey, S, Gaudi, BS, Gould, A, Henderson, CB, Johnson, S, Shvartzvald, Y, Zhu, W, Dominik, M, Hundertmark, M, Jorgensen, UG, Longa-Pena, P, Skottfelt, J, Tregloan-Reed, J, Bach-Moller, N, Burgdorf, M, D'Ago, G, Haikala, L, Hitchcock, J, Khalouei, E, Peixinho, N, Rahvar, S, Snodgrass, C, Southworth, J, Spyratos, P, Zang, W, Yang, H, Mao, S, Bachelet, E, Maoz, D, Street, RA, Tsapras, Y, Christie, GW, Cooper, T, de Almeida, L, Jr, DNJ-D, Green, J, Han, C, Hennerley, S, Marmont, A, McCormick, J, Monard, LAG, Natusch, T, Pogge, R, Collaboration, OGLE, Collaboration, MOA, Team, S, Consortium, M, Collaboration, LCOFUN, European Commission, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science

Subjects
GRAVITATIONAL LENS, FOS: Physical sciences, CHEMICAL EVOLUTION, Astrophysics::Cosmology and Extragalactic Astrophysics, GALACTIC BULGE, Q1, general [binaries], QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, PHOTOMETRY, low-mass [stars], QC, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), QB, Earth and Planetary Astrophysics (astro-ph.EP), OPTICAL DEPTH, Astronomy and Astrophysics, 3rd-DAS, PLANET CANDIDATE, Astrophysics - Astrophysics of Galaxies, DIFFERENCE IMAGE-ANALYSIS, SPITZER, low mass [Stars], QC Physics, Astrophysics - Solar and Stellar Astrophysics, GIANT PLANETS, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), DISCOVERY, micro [gravitational lensing], Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics, brown dwarfs
Abstract

Context. Brown dwarfs are poorly understood transition objects between stars and planets, with several competing mechanisms having been proposed for their formation. Mass measurements are generally difficult for isolated objects but also for brown dwarfs orbiting low-mass stars, which are often too faint for spectroscopic follow-up. Aims. Microlensing provides an alternative tool for the discovery and investigation of such faint systems. Here we present the analysis of the microlensing event OGLE-2019-BLG-0033/MOA-2019-BLG-035, which is due to a binary system composed of a brown dwarf orbiting a red dwarf. Methods. Thanks to extensive ground observations and the availability of space observations from Spitzer, it has been possible to obtain accurate estimates of all microlensing parameters, including parallax, source radius and orbital motion of the binary lens. Results. After accurate modeling, we find that the lens is composed of a red dwarf with mass $M_1 = 0.149 \pm 0.010M_\odot$ and a brown dwarf with mass $M_2 = 0.0463 \pm 0.0031M_\odot$, at a projected separation of $a_\perp = 0.585$ au. The system has a peculiar velocity that is typical of old metal-poor populations in the thick disk. Percent precision in the mass measurement of brown dwarfs has been achieved only in a few microlensing events up to now, but will likely become common with the Roman space telescope., Comment: 13 pages, 6 figures

Published
2022
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2. An isolated stellar-mass black hole detected through astrometric microlensing

Author

Sahu, KC, Anderson, J, Casertano, S, Bond, HE, Udalski, A, Dominik, M, Calamida, A, Bellini, A, Brown, TM, Rejkuba, M, Bajaj, V, Kains, N, Ferguson, HC, Fryer, CL, Yock, P, Mroz, P, Kozlowski, S, Pietrukowicz, P, Poleski, R, Skowron, J, Soszynski, I, Szymanski, MK, Ulaczyk, K, Wyrzykowski, L, Barry, R, Bennett, DP, Bond, IA, Hirao, Y, Silva, SI, Kondo, I, Koshimoto, N, Ranc, C, Rattenbury, NJ, Sumi, T, Suzuki, D, Tristram, PJ, Vandorou, A, Beaulieu, J-P, Marquette, J-B, Cole, A, Fouque, P, Hill, K, Dieters, S, Coutures, C, Dominis-Prester, D, Bennett, C, Bachelet, E, Menzies, J, Albrow, M, Pollard, K, Gould, A, Yee, J, Allen, W, Almeida, LA de, Christie, G, Drummond, J, Gal-Yam, A, Gorbikov, E, Jablonski, F, Lee, C-U, Maoz, D, Manulis, I, McCormick, J, Natusch, T, Pogge, RW, Shvartzvald, Y, Jorgensen, UG, Alsubai, KA, Andersen, MI, Bozza, V, Novati, SC, Hinse, TC, Hundertmark, M, Husser, T-O, Kerins, E, Longa-Pena, P, Mancini, L, Penny, M, Rahvar, S, Ricci, D, Sajadian, S, Skottfelt, J, Snodgrass, C, Southworth, J, Tregloan-Reed, J, Wambsganss, J, Wertz, O, Tsapras, Y, Street, RA, Bramich, DM, Horne, K, Steele, IA, STScI, PSU, Warsaw, Univ, Andrews, Univ St, ESO, Columbia, Univ, Lab, Los Alamos Nat, Auckland, Univ, Warwick, Univ, Centre, NASA Goddard Space Flight, Maryland, Univ, Univ, Massey, Univ, Osaka, America, Catholic Univ of, Heidelberg, Univ, Obs, Mt John, Zealand, New, Tasmania, Univ, Paris, IAP, Bordeaux, Univ, Toulouse, Univ, Japan, Nat Astron Obs, MIT, Obs, Las Cumbres, SAAO, Africa, South, Canterbury, Univ, Astronomy, Max-Planck-Inst for, Heidelberg, Univ, Ohio State, CfA, Cambridge, Obs, Vintage Lane, Norte, Univ Federal do Rio Grande do, Natal, Brazil, Mossoró, Obs, Auckland, Obs, Possum, Queensland, Univ Southern, Australia, Sci, Weizmann Inst of, Univ, Tel-Aviv, Israel, Espacias, Inst Nacional de Pesquisas, Astron, Korea, Inst, Space Sci, Sci, Weizmann Inst, Obs, Farm Cove, IRASR, Copenhagen, Univ, QEERI, Doha, Qatar, Denmark, Salerno, Univ, Italy, Napoli, INFN, IPAC, Pasadena, Toruń, Nicolaus Copernicus Univ, Univ, Chungnam Nat, Korea, South, Göttingen, Univ, Germany, Astroph, Jodrell Bank Centre, Manchester, Antofagasta, Univ, Rome, Univ, Turin, INAF, Univ, Louisiana State, Tech, Sharif Univ of, Tehran, Padova, INAF, Tech, Isfahan Univ, Univ, Open, Keynes, Milton, Edinburgh, Univ, Univ, Keele, Atacama, Univ, Chile, Liège, Univ, Dhabi, NY Univ Abu, Univ, Liverpool John Moores, Collaboration, OGLE, Collaboration, MOA, Collaboration, PLANET, Collaboration, microFUN, Consortium, MiNDSTEp, Collaboration, RoboNet, ITA, USA, GBR, European Commission, University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and ANR-18-CE31-0002,COLD-WORLDS,Statistiques des planètes proches de leur lieu de formation et leur distribution dans le disque et la barre de notre Galaxie(2018)

Subjects
GRAVITATIONAL LENS, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, PARALLAX, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, EVENTS, Black holes, 162, 672, Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Astrophysics of Galaxies, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics::Solar and Stellar Astrophysics, PHOTOMETRY, QB Astronomy, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, QC, QB, High Energy Astrophysical Phenomena (astro-ph.HE), MCC, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], STAR, Settore FIS/05, Astronomy and Astrophysics, BINARY, 3rd-DAS, EVOLUTION, QC Physics, DEFLECTION, RESOLUTION, [SDU]Sciences of the Universe [physics], Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, Block holes, PLANETS
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 six years, 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 the 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 Msun 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, 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., 37 pages, Published in ApJ

Published
2022
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3. OGLE-2017-BLG-0406: Spitzer Microlens Parallax Reveals Saturn-mass Planet Orbiting M-dwarf Host in the Inner Galactic Disk

Author

Hirao, Y, Bennett, DP, Ryu, Y-H, Koshimoto, N, Udalski, A, Yee, JC, Sumi, T, Bond, IA, Shvartzvald, Y, Abe, F, Barry, RK, Bhattacharya, A, Donachie, M, Fukui, A, Itow, Y, Kondo, I, Li, MCA, Matsubara, Y, Matsuo, T, Miyazaki, S, Muraki, Y, Nagakane, M, Ranc, C, Rattenbury, NJ, Suematsu, H, Shibai, H, Suzuki, D, Tristram, PJ, Yonehara, A, Skowron, J, Poleski, R, Mroz, P, Szymanski, MK, Soszynski, I, Kozlowski, S, Pietrukowicz, P, Ulaczyk, K, Rybicki, K, Iwanek, P, Albrow, MD, Chung, S-J, Gould, A, Han, C, Hwang, K-H, Jung, YK, Shin, I-G, Zang, W, Cha, S-M, Kim, D-J, Kim, H-W, Kim, S-L, Lee, C-U, Lee, D-J, Lee, Y, Park, B-G, Pogge, RW, Beichman, CA, Bryden, G, Novati, SC, Carey, S, Gaudi, BS, Henderson, CB, Zhu, W, Bachelet, E, Bolt, G, Christie, G, Hundertmark, M, Natusch, T, Maoz, D, McCormick, J, Street, RA, Tan, T-G, Tsapras, Y, Jorgensen, UG, Dominik, M, Bozza, V, Skottfelt, J, Snodgrass, C, Ciceri, S, Jaimes, RF, Evans, DF, Peixinho, N, Hinse, TC, Burgdorf, MJ, Southworth, J, Rahvar, S, Sajadian, S, Rabus, M, von Essen, C, Fujii, YI, Campbell-White, J, Lowry, S, Helling, C, Mancini, L, Haikala, L, Kandori, R, Collaboration, MOA, Collaboration, OGLE, Collaboration, K, Team, S, Teams, LCOFF-U, Collaboration, M, Team, IRSF, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science

Subjects
010504 meteorology & atmospheric sciences, GRAVITATIONAL LENSING EXPERIMENT, Astrophysics, 01 natural sciences, JUPITER/SATURN ANALOG, Bulge, Planet, Saturn, QB Astronomy, 010303 astronomy & astrophysics, QC, QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, education.field_of_study, Settore FIS/05, LUMINOSITY-RELATION, INTERSTELLAR EXTINCTION LAW, Astrophysics - Solar and Stellar Astrophysics, MILKY-WAY, Astrophysics::Earth and Planetary Astrophysics, Proper motion, astro-ph.SR, astro-ph.GA, Population, NDAS, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, Gravitational microlensing exoplanet detection, EVENTS, SYSTEMS, 0103 physical sciences, PHOTOMETRY, DETERMINISTIC MODEL, education, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Astronomy and Astrophysics, Mass ratio, Light curve, Astrophysics - Astrophysics of Galaxies, QC Physics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), astro-ph.EP, STARS, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report the discovery and analysis of the planetary microlensing event OGLE-2017-BLG-0406, which was observed both from the ground and by the ${\it Spitzer}$ satellite in a solar orbit. At high magnification, the anomaly in the light curve was densely observed by ground-based-survey and follow-up groups, and it was found to be explained by a planetary lens with a planet/host mass ratio of $q=7.0 \times 10^{-4}$ from the light-curve modeling. The ground-only and ${\it Spitzer}$-"only" data each provide very strong one-dimensional (1-D) constraints on the 2-D microlens parallax vector $\bf{\pi_{\rm E}}$. When combined, these yield a precise measurement of $\bf{\pi_{\rm E}}$, and so of the masses of the host $M_{\rm host}=0.56\pm0.07\,M_\odot$ and planet $M_{\rm planet} = 0.41 \pm 0.05\,M_{\rm Jup}$. The system lies at a distance $D_{\rm L}=5.2 \pm 0.5 \ {\rm kpc}$ from the Sun toward the Galactic bulge, and the host is more likely to be a disk population star according to the kinematics of the lens. The projected separation of the planet from the host is $a_{\perp} = 3.5 \pm 0.3 \ {\rm au}$, i.e., just over twice the snow line. The Galactic-disk kinematics are established in part from a precise measurement of the source proper motion based on OGLE-IV data. By contrast, the ${\it Gaia}$ proper-motion measurement of the source suffers from a catastrophic $10\,\sigma$ error., Comment: 40 pages, 12 figures, 10 tables, accepted for publication in The Astronomical Journal

Published
2020
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4. SPITZER PARALLAX of OGLE-2015-BLG-0966: A COLD NEPTUNE in the GALACTIC DISK

Author

Street, RA, Udalski, A, Novati, SC, Hundertmark, MPG, Zhu, W, Gould, A, Yee, J, Tsapras, Y, Bennett, DP, Jorgensen, UG, Dominik, M, Andersen, MI, Bachelet, E, Bozza, V, Bramich, DM, Burgdorf, MJ, Cassan, A, Ciceri, S, D'Ago, G, Dong, S, Evans, DF, Gu, S-H, Harkonnen, H, Hinse, TC, Horne, K, Jaimes, RF, Kains, N, Kerins, E, Korhonen, H, Kuffmeier, M, Mancini, L, Menzies, J, Mao, S, Peixinho, N, Popovas, A, Rabus, M, Rahvar, S, Ranc, C, Rasmussen, RT, Scarpetta, G, Schmidt, R, Skottfelt, J, Snodgrass, C, Southworth, J, Steele, IA, Surdej, J, Unda-Sanzana, E, Verma, P, Von Essen, C, Wambsganss, J, Wang, Y-B, Wertz, O, Poleski, R, Pawlak, M, Szymanski, MK, Skowron, J, Mroz, P, Kozlowski, S, Wyrzykowski, L, Pietrukowicz, P, Pietrzynski, G, Soszynski, I, Ulaczyk, K, Beichman, C, Bryden, G, Carey, S, Gaudi, BS, Henderson, CB, Pogge, RW, Shvartzvald, Y, Abe, F, Asakura, Y, Bhattacharya, A, Bond, IA, Donachie, M, Freeman, M, Fukui, A, Hirao, Y, Inayama, K, Itow, Y, Koshimoto, N, Li, MCA, Ling, CH, Masuda, K, Matsubara, Y, Muraki, Y, Nagakane, M, Nishioka, T, Ohnishi, K, Oyokawa, H, Rattenbury, N, Saito, T, Sharan, A, Sullivan, DJ, Sumi, T, Suzuki, D, Tristram, J, Wakiyama, Y, Yonehara, A, Han, C, Choi, J-Y, Park, H, Jung, YK, Shin, I-G, Project, R, Consortium, M, Project, OGLE, Team, S, Collaboration, MOA, Team, KM, and University of St Andrews. School of Physics and Astronomy

Subjects
Astrophysics::High Energy Astrophysical Phenomena, NDAS, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, gravitational lensing: micro, 01 natural sciences, micro [Gravitational lensing], Settore FIS/05 - Astronomia e Astrofisica, Neptune, Bulge, Planet, Space and Planetary Science, Astronomy and Astrophysics, 0103 physical sciences, QB Astronomy, Disc, 010303 astronomy & astrophysics, R2C, QC, Astrophysics::Galaxy Astrophysics, QB, Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010308 nuclear & particles physics, ~DC~, Galactic Center, Astronomy, QC Physics, Astrophysics::Earth and Planetary Astrophysics, Sample integrity, BDC, Parallax, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report the detection of a Cold Neptune m_planet=21+/-2MEarth orbiting a 0.38MSol M dwarf lying 2.5-3.3 kpc toward the Galactic center as part of a campaign combining ground-based and Spitzer observations to measure the Galactic distribution of planets. This is the first time that the complex real-time protocols described by Yee et al. (2015), which aim to maximize planet sensitivity while maintaining sample integrity, have been carried out in practice. Multiple survey and follow-up teams successfully combined their efforts within the framework of these protocols to detect this planet. This is the second planet in the Spitzer Galactic distribution sample. Both are in the near-to-mid disk and clearly not in the Galactic bulge., 28 pages, 3 figures, 2 tables, submitted to ApJ

Published
2016
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5. Many new variable stars discovered in the core of the globular cluster NGC 6715 (M 54) with EMCCD observations

Author

Jaimes, RF, Bramich, DM, Kains, N, Skottfelt, J, Jorgensen, UG, Horne, K, Dominik, M, Alsubai, KA, Bozza, V, Burgdorf, MJ, Novati, SC, Ciceri, S, D'Ago, G, Evans, DF, Galianni, P, Gu, S-H, Harpsoe, KBW, Haugbolle, T, Hinse, TC, Hundertmark, M, Juncher, D, Kerins, E, Korhonen, H, Kuffmeier, M, Mancini, L, Peixinho, N, Popovas, A, Rabus, M, Rahvar, S, Scarpetta, G, Schmidt, RW, Snodgrass, C, Southworth, J, Starkey, D, Street, RA, Surdej, J, Tronsgaar, R, Unda-Sanzana, E, von Essen, C, Wang, X-B, Wertz, O, Consortium, M, Science & Technology Facilities Council, and University of St Andrews. School of Physics and Astronomy

Subjects
SAGITTARIUS DWARF GALAXY, Stars: variables: general, observational [methods], Crowded fields, Astrophysics, RR Lyrae variable, GALACTIC BULGE, 01 natural sciences, law.invention, Methods: observational, law, Globular clusters, Astrophysics::Solar and Stellar Astrophysics, QB Astronomy, 010303 astronomy & astrophysics, QC, QB, Physics, education.field_of_study, Astrophysics::Instrumentation and Methods for Astrophysics, Atmospheric effects, Globular clusters: individual: NGC 6715 (M 54), Instrumentation: high angular resolution, Stars: variables: RR Lyrae, Astronomy and Astrophysics, Space and Planetary Science, DIFFERENCE IMAGE-ANALYSIS, RR-LYRAE VARIABLES, Astrophysics - Solar and Stellar Astrophysics, OOSTERHOFF DICHOTOMY, Astrophysics::Earth and Planetary Astrophysics, individual: NGC 6715 (M54) [globular clusters], atmospheric effects, Population, NDAS, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, variables: RR Lyrae [stars], Telescope, Photometry (optics), Settore FIS/05 - Astronomia e Astrofisica, 0103 physical sciences, CROWDED CENTRAL REGION, education, Solar and Stellar Astrophysics (astro-ph.SR), individual: NGC 6715 (M 54) [Globular clusters], Astrophysics::Galaxy Astrophysics, 010308 nuclear & particles physics, NGC 6715, variable stars, Light curve, Stars, QC Physics, SPHEROIDAL GALAXY, variables: general [stars], Globular cluster, BLACK-HOLE, Variable star, ACS SURVEY, DYNAMICAL MODELS, high angular resolution [instrumentation]
Abstract

We show the benefits of using Electron-Multiplying CCDs and the shift-and-add technique as a tool to minimise the effects of the atmospheric turbulence such as blending between stars in crowded fields and to avoid saturated stars in the fields observed. We intend to complete, or improve, the census of the variable star population in globular cluster NGC~6715. Our aim is to obtain high-precision time-series photometry of the very crowded central region of this stellar system via the collection of better angular resolution images than has been previously achieved with conventional CCDs on ground-based telescopes. Observations were carried out using the Danish 1.54-m Telescope at the ESO La Silla observatory in Chile. The telescope is equipped with an Electron-Multiplying CCD that allowed to obtain short-exposure-time images (ten images per second) that were stacked using the shift-and-add technique to produce the normal-exposure-time images (minutes). The high precision photometry was performed via difference image analysis employing the DanDIA pipeline. We attempted automatic detection of variable stars in the field. We statistically analysed the light curves of 1405 stars in the crowded central region of NGC~6715 to automatically identify the variable stars present in this cluster. We found light curves for 17 previously known variable stars near the edges of our reference image (16 RR Lyrae and 1 semi-regular) and we discovered 67 new variables (30 RR Lyrae, 21 long-period irregular, 3 semi-regular, 1 W Virginis, 1 eclipsing binary, and 11 unclassified). Photometric measurements for these stars are available in electronic form through the Strasbourg Astronomical Data Centre., Accepted for publication in Astronomy & Astrophysics, 18 pages, 7 figures, 4 tables

Published
2016
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6. Spitzer Microlensing Program as a Probe for Globular Cluster Planets. Analysis of OGLE-2015-BLG-0448

Author

Poleski, R, Zhu, W, Christie, GW, Udalski, A, Gould, A, Bachelet, E, Skottfelt, J, Novati, SC, Szymanski, MK, Soszynski, I, Pietrzynski, G, Wyrzykowski, L, Ulaczyk, K, Pietrukowicz, P, Kozlowski, S, Skowron, J, Mroz, P, Pawlak, M, Beichman, C, Bryden, G, Carey, S, Fausnaugh, M, Gaudi, BS, Henderson, CB, Pogge, RW, Shvartzvald, Y, Wibking, B, Yee, JC, Beatty, TG, Eastman, JD, Drummond, J, Friedmann, M, Henderson, M, Johnson, JA, Kaspi, S, Maoz, D, McCormick, J, McCrady, N, Natusch, T, Ngan, H, Porritt, I, Relles, HM, Sliski, DH, Tan, T-G, Wittenmyer, RA, Wright, JT, Street, RA, Tsapras, Y, Bramich, DM, Horne, K, Snodgrass, C, Steele, IA, Menzies, J, Jaimes, RF, Wambsganss, J, Schmidt, R, Cassan, A, Ranc, C, Mao, S, Bozza, V, Dominik, M, Hundertmark, MPG, Jorgensen, UG, Andersen, MI, Burgdorf, MJ, Ciceri, S, D'Ago, G, Evans, DF, Gu, S-H, Hinse, TC, Kains, N, Kerins, E, Korhonen, H, Kuffmeier, M, Mancini, L, Popovas, A, Rabus, M, Rahvar, S, Rasmussen, RT, Scarpetta, G, Southworth, J, Surdej, J, Unda-Sanzana, E, Verma, P, von Essen, C, Wang, Y-B, Wertz, O, Grp, OGLE, Team, S, Grp, FUN, Project, R, Grp, M, and University of St Andrews. School of Physics and Astronomy

Subjects
planets and satellites: detection, Proper motion, detection [planets and satellites], NDAS, GRAVITATIONAL LENSING EXPERIMENT, FOS: Physical sciences, Astrophysics, gravitational lensing: micro, Astrophysics::Cosmology and Extragalactic Astrophysics, 010501 environmental sciences, GALACTIC BULGE, Gravitational microlensing, 01 natural sciences, Settore FIS/05 - Astronomia e Astrofisica, proper motions, Planet, SYSTEMS, 0103 physical sciences, Cluster (physics), QB Astronomy, PHOTOMETRY, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, QC, 0105 earth and related environmental sciences, QB, Physics, globular clusters: individual (NGC6558), RR LYRAE STARS, MILKY-WAY BULGE, Astronomy and Astrophysics, Radius, Light curve, OGLE-III, DIFFERENCE IMAGE-ANALYSIS, CATALOG, Space and Planetary Science, Photometry (astronomy), RED CLUMP, QC Physics, Astrophysics - Solar and Stellar Astrophysics, Globular cluster, individual (NGC6558) [globular clusters], micro [gravitational lensing], individual: NGC6558 [Globular clusters], Astrophysics::Earth and Planetary Astrophysics
Abstract

The microlensing event OGLE-2015-BLG-0448 was observed by Spitzer and lay within the tidal radius of the globular cluster NGC 6558. The event had moderate magnification and was intensively observed, hence it had the potential to probe the distribution of planets in globular clusters. We measure the proper motion of NGC 6558 ($\mu_{\rm cl}$(N,E) = (+0.36+-0.10, +1.42+-0.10) mas/yr) as well as the source and show that the lens is not a cluster member. Even though this particular event does not probe the distribution of planets in globular clusters, other potential cluster lens events can be verified using our methodology. Additionally, we find that microlens parallax measured using OGLE photometry is consistent with the value found based on the light curve displacement between Earth and Spitzer., Comment: ApJ submitted, 12 pages, 8 figures, 2 tabels

Published
2015
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7. 21 Pathway To The Galactic Distribution Of Planets: Combined Spitzer And Ground-Based Microlens Parallax Measurements Of Single-Lens Events

Author

Novati, SC, Gould, A, Udalski, A, Menzies, JW, Bond, IA, Shvartzvald, Y, Street, RA, Hundertmark, M, Beichman, CA, Yee, JC, Carey, S, Poleski, R, Skowron, J, Kozlowski, S, Mroz, P, Pietrukowicz, P, Pietrzynski, G, Szymanski, MK, Soszynski, I, Ulaczyk, K, Wyrzykowski, L, Albrow, M, Beaulieu, JP, Caldwell, JAR, Cassan, A, Coutures, C, Danielski, C, Prester, DD, Donatowicz, J, Loncaric, K, McDougall, A, Morales, JC, Ranc, C, Zhu, W, Abe, F, Barry, RK, Bennett, DP, Bhattacharya, A, Fukunaga, D, Inayama, K, Koshimoto, N, Namba, S, Sumi, T, Suzuki, D, Tristram, PJ, Wakiyama, Y, Yonehara, A, Maoz, D, Kaspi, S, Friedmann, M, Bachelet, E, Jaimes, RF, Bramich, DM, Tsapras, Y, Horne, K, Snodgrass, C, Wambsganss, J, Steele, IA, Kains, N, Bozza, V, Dominik, M, Jorgensen, UG, Alsubai, KA, Ciceri, S, D'Ago, G, Haugbolle, T, Hessman, FV, Hinse, TC, Juncher, D, Korhonen, H, Mancini, L, Popovas, A, Rabus, M, Rahvar, S, Scarpetta, G, Schmidt, RW, Skottfelt, J, Southworth, J, Starkey, D, Surdej, J, Wertz, O, Zarucki, M, Gaudi, BS, Pogge, RW, De Poy, DL, Collaboration, TOGLE, Collaboration, TPLANET, Collaboration, TMOA, Grp, TW, Collaboration, TR, Consortium, TM, Collaboration, TFUN, The Royal Society, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, Department of Astronomy (Ohio State University), Ohio State University [Columbus] (OSU), Astronomical Observatory [Warsaw], Faculty of Physics [Warsaw] (FUW), University of Warsaw (UW)-University of Warsaw (UW), Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), NASA Goddard Space Flight Center (GSFC), Department of Physics and Astronomy [Baltimore], Johns Hopkins University (JHU), Osaka University [Osaka], Department of Earth and Space Science [Toyonaka-shi], Osaka University, Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Max-Planck-Institut für Sonnensystemforschung (MPS), Kuopio Unit [FMI], Finnish Meteorological Institute (FMI), Elettra Sincrotrone Trieste, Instituto de Astrofisica de Canarias (IAC), Department of Physics [Tehran], Sharif University of Technology [Tehran] (SUT), Space Science Department of ESA, European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), DeKalb Observatory, Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, Argelander Institute for Astronomy (AlfA), Rheinische Friedrich-Wilhelms-Universität Bonn, Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), and Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA)

Subjects
FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, law.invention, micro [Gravitational lensing], Settore FIS/05 - Astronomia e Astrofisica, gravitational lensing: micro — planets, Bulge, Planet, law, QB Astronomy, Projection (set theory), ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, QC, QB, Earth and Planetary Astrophysics (astro-ph.EP), Microlens, Physics, [PHYS]Physics [physics], Cumulative distribution function, Astronomy, Astronomy and Astrophysics, 3rd-DAS, dynamical evolution and stability [Planets and satellites], Galaxy, Lens (optics), Planetary systems, QC Physics, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Parallax, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract

We present microlens parallax measurements for 21 (apparently) isolated lenses observed toward the Galactic bulge that were imaged simultaneously from Earth and Spitzer, which was ~1 AU West of Earth in projection. We combine these measurements with a kinematic model of the Galaxy to derive distance estimates for each lens, with error bars that are small compared to the Sun's Galactocentric distance. The ensemble therefore yields a well-defined cumulative distribution of lens distances. In principle it is possible to compare this distribution against a set of planets detected in the same experiment in order to measure the Galactic distribution of planets. Since these Spitzer observations yielded only one planet, this is not yet possible in practice. However, it will become possible as larger samples are accumulated., accepted for publication in ApJ

Published
2015
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8. A census of variability in globular cluster M 68 (NGC 4590)

Author

Kains, N, Arellano Ferro, A, Jaimes, RF, Bramich, DM, Skottfelt, J, Jorgensen, UG, Tsapras, Y, Street, RA, Browne, P, Dominik, M, Horne, K, Hundertmark, M, Ipatov, S, Snodgrass, C, Steele, IA, Alsubai, KA, Bozza, V, Novati, SC, Ciceri, S, D'Ago, G, Galianni, P, Gu, S-H, Harpsoe, K, Hinse, TC, Juncher, D, Korhonen, H, Mancini, L, Popovas, A, Rabus, M, Rahvar, S, Southworth, J, Surdej, J, Vilela, C, Wang, X-B, Wertz, O, Consortium, LCOGTR, Consortium, M, The Royal Society, Science & Technology Facilities Council, and University of St Andrews. School of Physics and Astronomy

Subjects
Metallicity, Globular clusters: individual: M 68, Stars: variables: general, NDAS, FOS: Physical sciences, Astrophysics, variables: RR Lyrae [Stars], RR Lyrae variable, variables: general [Stars], Stars: variables: RR Lyrae, Astronomy and Astrophysics, Space and Planetary Science, Photometry (optics), Settore FIS/05 - Astronomia e Astrofisica, QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), QC, Astrophysics::Galaxy Astrophysics, QB, Physics, Light curve, individual: M 68 [Globular clusters], Distance modulus, Stars, QC Physics, Astrophysics - Solar and Stellar Astrophysics, Globular cluster, Variable star
Abstract

We analyse 20 nights of CCD observations in the V and I bands of the globular cluster M68 (NGC 4590), using these to detect variable objects. We also obtained electron-multiplying CCD (EMCCD) observations for this cluster in order to explore its core with unprecedented spatial resolution from the ground. We reduced our data using difference image analysis, in order to achieve the best possible photometry in the crowded field of the cluster. In doing so, we showed that when dealing with identical networked telescopes, a reference image from any telescope may be used to reduce data from any other telescope, which facilitates the analysis significantly. We then used our light curves to estimate the properties of the RR Lyrae (RRL) stars in M68 through Fourier decomposition and empirical relations. The variable star properties then allowed us to derive the cluster's metallicity and distance. We determine new periods for the variable stars, and search for new variables, especially in the core of the cluster where our method performs particularly well. We detect an additional 4 SX Phe stars, and confirm the variability of another star, bringing the total number of confirmed variable stars in this cluster to 50. We also used archival data stretching back to 1951 in order to derive period changes for some of the single-mode RRL stars, and analyse the significant number of double-mode RRL stars in M68. Furthermore, we find evidence for double-mode pulsation in one of the SX Phe stars in this cluster. Using the different types of variables, we derived an estimate of the metallicity, [Fe/H]=$-2.07 \pm 0.06$ on the ZW scale, and 4 independent estimates of the distance modulus ($\mu_0 \sim$ 15.00 mag) for this cluster. Thanks to the first use of difference image analysis on time-series observations of M68, we are now confident that we have a complete census of the RRL stars in this cluster., Comment: 25 pages, 18 figures, A&A in press

Published
2015

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