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5 results on '"J. J. Calitz"'

1. The Photometry Pipeline of the Watcher Robotic Telescope

Author

Riccardo Felletti, G. Melady, M. Hoffman, Martin Jelínek, J. French, Sheila McBreen, Pieter Meintjes, Alejandro Ferrero, B. McBreen, Lorraine Hanlon, J. J. Calitz, and Petr Kubánek

Subjects
Physics, Article Subject, lcsh:Astronomy, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, lcsh:QB1-991, Photometry (astronomy), Robotic telescope, Space and Planetary Science, Limiting magnitude, Variable star, Blazar, Remote sensing
Abstract

The Watcher robotic telescope was developed primarily to perform rapid optical follow-up observations of Gamma-Ray Bursts (GRBs). Secondary scientific goals include blazar monitoring and variable star studies. An automated photometry pipeline to rapidly analyse data from Watcher has been implemented. Details of the procedures to get image zero-point, source instrumental measurement, and limiting magnitude are presented. Sources of uncertainty are assessed and the performance of the pipeline is tested by comparison with a number of catalogue sources. Copyright © 2010 A. Ferrero et al.

Published
2010

2. OGLE-2005-BLG-153: Microlensing Discovery and Characterization of a Very Low Mass Binary

Author

Michael D. Albrow, Andrew Williams, J. P. Beaulieu, Kouji Ohnishi, D. J. Sullivan, Yoshitaka Itow, Nicholas J. Rattenbury, D. Dominis, L. Wyrzykowski, Misao Sasaki, Yasushi Muraki, D. M. Bramich, Kimiaki Masuda, Andrew Gould, D. Kubas, Keith Horne, P. J. Tristram, Iain A. Steele, Kasper Harpsøe, J. W. Menzies, B. S. Gaudi, Colin Snodgrass, P. Fouque, Arnaud Cassan, J. B. Marquette, Yoon-Hyun Ryu, M. Hoffman, Yutaka Matsubara, K.-H. Hwang, S. R. Kane, Kailash C. Sahu, Martin Burgdorf, Ian A. Bond, C. Okada, C. Vinter, To. Saito, Martin Dominik, John B. Hearnshaw, K. M. Hill, R. M. Martin, P. M. Kilmartin, J. N. Wood, C.-U. Lee, Darren L. DePoy, M. Desort, S. Dieters, J. Donatowicz, Byeong-Gon Park, D. P. Bennett, Fumio Abe, Philip Yock, M. Motomura, Igor Soszyński, J. J. Calitz, E. Corrales, K. R. Pollard, Joachim Wambsganss, J. G. Greenhill, Andrzej Udalski, Michał K. Szymański, O. Szewczyk, R. W. Pogge, K. Ulaczyk, U. G. Jørgensen, K. H. Cook, M. F. Bode, C. Han, Grzegorz Pietrzyński, Kisaku Kamiya, K. Woller, Takashi Sako, T. Yoshioka, J. A. R. Caldwell, P. J. Meintjes, C. Coutures, Stephane Brillant, C. S. Botzler, Takahiro Sumi, Shota Nakamura, and M. Kubiak

Subjects
binaries: general, gravitational lensing: micro, Population, Binary number, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, 01 natural sciences, Luminosity, Einstein radius, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, education, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Physics, education.field_of_study, 010308 nuclear & particles physics, Star formation, urogenital system, Astronomy and Astrophysics, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Low Mass
Abstract

The mass function and statistics of binaries provide important diagnostics of the star formation process. Despite this importance, the mass function at low masses remains poorly known due to observational difficulties caused by the faintness of the objects. Here we report the microlensing discovery and characterization of a binary lens composed of very low-mass stars just above the hydrogen-burning limit. From the combined measurements of the Einstein radius and microlens parallax, we measure the masses of the binary components of $0.10\pm 0.01\ M_\odot$ and $0.09\pm 0.01\ M_\odot$. This discovery demonstrates that microlensing will provide a method to measure the mass function of all Galactic populations of very low mass binaries that is independent of the biases caused by the luminosity of the population., Comment: 6 pages, 3 figures, 1 table

Published
2010

3. OGLE 2004-BLG-254: a K3 III Galactic Bulge Giant spatially resolved by a single microlens

Author

J. A. R. Caldwell, P. Fouque, D. Dominis, K. Zebrun, Keith Horne, Michael D. Albrow, Andrew Williams, D. Kubas, L. Wyrzykowski, R. M. Martin, H. C. Stempels, J. P. Beaulieu, J. Donatowicz, J. J. Calitz, K. H. Cook, C. Coutures, V. R. Miller, Stephane Brillant, K. R. Pollard, Martin Dominik, Arnaud Cassan, J. B. Marquette, Joachim Wambsganss, Andrzej Udalski, Michał K. Szymański, J. W. Menzies, M. Hoffman, U. G. Jørgensen, C. Vinter, Grzegorz Pietrzyński, K. Hill, M. Kubiak, P. J. Meintjes, Kailash C. Sahu, David P. Bennett, S. R. Kane, D. Heyrovsky, Igor Soszyński, J. G. Greenhill, O. Szewczyk, Institut d'Astrophysique de Paris (IAP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Astronomische Rechen-Institut [Heidelberg] (ARI), Zentrum für Astronomie der Universität Heidelberg (ZAH), Universität Heidelberg [Heidelberg] = Heidelberg University-Universität Heidelberg [Heidelberg] = Heidelberg University, Laboratoire d'Astrophysique de l'Observatoire Midi-Pyrénées (LATT), 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), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Universität Heidelberg [Heidelberg]-Universität Heidelberg [Heidelberg], Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)

Subjects
gravitational lensing, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Bulge, Planet, individual: OGLE 2004-BLG-254, 0103 physical sciences, stars: atmospheres, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Spectrograph, Astrophysics::Galaxy Astrophysics, Physics, 010308 nuclear & particles physics, Astrophysics (astro-ph), stars, Astrophysics::Instrumentation and Methods for Astrophysics, techniques: high angular resolution, Astronomy and Astrophysics, Light curve, Stars, Space and Planetary Science, Limb darkening, Astrophysics::Earth and Planetary Astrophysics, Event (particle physics)
Abstract

We present an analysis of OGLE 2004-BLG-254, a high-magnification and relatively short duration microlensing event in which the source star, a Bulge K3-giant, has been spatially resolved by a point-like lens. We have obtained dense photometric coverage of the event light curve with OGLE and PLANET telescopes, as well as a high signal-to-noise ratio spectrum taken while the source was still magnified by 20, using the UVES/VLT spectrograph. Our dense coverage of this event allows us to measure limb darkening of the source star in the I and R bands. We also compare previous measurements of linear limb-darkening coefficients involving GK-giant stars with predictions from ATLAS atmosphere models. We discuss the case of K-giants and find a disagreement between limb-darkening measurements and model predictions, which may be caused by the inadequacy of the linear limb-darkening law., Comment: 14 pages, 8 figures, accepted for publication in A&A (04/09/2006)

Published
2006
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4. The unusual optical afterglow of the gamma-ray burst GRB 021004: Color changes and short-time-scale variability

Author

D. Bersier, K. Z. Stanek, J. N. Winn, T. Grav, M. J. Holman, T. Matheson, B. Mochejska, D. Steeghs, A. R. Walker, P. M. Garnavich, J. Quinn, S. Jha, K. H. Cook, W. W. Craig, P. J. Meintjes, and J. J. Calitz

Subjects
Physics, 010308 nuclear & particles physics, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Scale (descriptive set theory), Context (language use), Astrophysics, 01 natural sciences, Power law, Afterglow, Space and Planetary Science, Color changes, 0103 physical sciences, Gamma-ray burst, 010303 astronomy & astrophysics
Abstract

We report UBVRI observations of the optical afterglow of the gamma-ray burst GRB 021004. We observed significant (10-20%) deviations from a power law decay on several time scales, ranging from a few hours down to 20-30 minutes. We also observed a significant color change starting ~1.5 days after the burst, confirming the spectroscopic results already reported by Matheson et al. (2002). We discuss these results in the context of several models that have recently been proposed to account for the anomalous photometric behavior of this event., Comment: Submitted to ApJL, 14 pages, 4 figures. Data available on anonymous ftp at ftp://cfa-ftp.harvard.edu/pub/kstanek/GRB021004

Published
2002
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5. Gravitational Microlensing Events Due to Stellar Mass Black Holes

Author

J. J. Calitz, Sun Hong Rhie, Douglas L. Welch, Charles Alcock, M. R. Pratt, Dante Minniti, S. L. Marshall, Christopher W. Stubbs, William J. Sutherland, Kem H Cook, R. A. Allsman, Bruce A. Peterson, Tim Axelrod, David R. Alves, P. C. Fragile, Andrew J. Drake, David P. Bennett, P. Popowski, C. Laws, Kenneth C. Freeman, Peter J. Quinn, Kim Griest, Stefan Keller, Andrew C. Becker, Bradley R. Johnson, J. Quinn, T. Vandehei, Matthew J. Lehner, C. A. Nelson, Austin B. Tomaney, and Marla Geha

Subjects
Physics, Stellar mass, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Compact star, Gravitational microlensing, law.invention, Lens (optics), Black hole, Stars, Space and Planetary Science, Bulge, law, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Main sequence, Astrophysics::Galaxy Astrophysics
Abstract

We present an analysis of the longest timescale microlensing events discovered by the MACHO Collaboration during a 7 year survey of the Galactic bulge. We find 6 events that exhibit very strong microlensing parallax signals due, in part, to accurate photometric data from the GMAN and MPS collaborations. The microlensing parallax fit parameters are used in a likelihood analysis, which is able to estimate the distance and masses of the lens objects based upon a standard model of the Galactic velocity distribution. This analysis indicates that the most likely masses of 5 of the 6 lenses are > 1 Msun, which suggests that a substantial fraction of the Galactic lenses may be massive stellar remnants. This could explain the observed excess of long timescale microlensing events. The lenses for events MACHO-96-BLG-5 and MACHO-98-BLG-6 are the most massive, with mass estimates of M/Msun = 6 +10/-3 and M/Msun = 6 +7/-3, respectively. The observed upper limits on the absolute brightness of main sequence stars for these lenses are < 1 Lsun, so both lenses are black hole candidates. The black hole interpretation is also favored by a likelihood analysis with a Bayesian prior using a conventional model for the lens mass function. We consider the possibility that the source stars for some of these 6 events may lie in the foreground or background of the Galactic bulge, but we find that this is unlikely. Future HST observations of these events can either confirm the black hole lens hypothesis or detect the lens stars and provide a direct measurement of their masses. Future observations of similar events by SIM or the Keck or VLTI interferometers will allow direct measurements of the lens masses for stellar remnant lenses as well., 47 pages, with 26 included postscript figures. Includes a new likelihood analysis with a mass function prior

Published
2001
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