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Browsing by Author "Bramich, D. M"

Browsing by Author "Bramich, D. M"

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  • CCD Photometry of the globular cluster M2. RR Lyrae physical parameters and new variables 
    Lazaro, C; Arellano Ferro, A; Arevalo, M. J; Bramich, D. M; Giridhar, S; Poretti, E (Wiley-Blackwell, 2006-10)
    We report the results of CCD V and R photometry of the RR Lyrae stars in M2. The periodicities of most variables are revised and new ephemerides are calculated. Light curve decomposition of the RR Lyrae stars was carried ...
  • CCD photometry of the globular cluster NGC 5466. RR Lyrae light-curve decomposition and the distance scale 
    Arellano Ferro, A; Rojas López, V; Giridhar, S; Bramich, D. M (Blackwell Synergy, 2008-03)
    We report the results of CCD V and r photometry of the globular cluster NGC 5466. The difference image analysis technique adopted in this work has resulted in accurate time-series photometry even in crowded regions of the ...
  • CCD Photometry of the RR Lyrae Stars in NGC4147 
    Arellano Ferro, A; Arévalo, M. J; Lázaro, C; Rey, M; Bramich, D. M; Giridhar, S (Instituto de Astronomía, Universidad Nacional Autónoma de México, 2004-10)
    We report the results of CCD V and R photometry of the RRstars known in NGC4147. The periodicities of most variables are revised and new ephemerides are calculated. The Blazhko effect has been detected in V2 and V6. Three ...
  • CCD time-series photometry of the globular cluster NGC 5053: RR Lyrae, Blue Stragglers and SX Phoenicis stars revisited 
    Arellano Ferro, A; Giridhar, S; Bramich, D. M (Blackwell Publishing, 2010-02)
    We report the results of CCD V, r and I time-series photometry of the globular cluster NGC 5053. New times of maximum light are given for the eight known RR Lyrae stars in the field of our images, and their periods are ...
  • CCD time-series photometry of the globular cluster NGC 6981: variable star census and physical parameter estimates 
    Bramich, D. M; Figuera Jaimes, R; Giridhar, S; Arellano Ferro, A (Wiley-Blackwell, 2011-05)
    We present the results from 10 nights of observations of the globular cluster NGC 6981 (M72) in the V, R and I Johnson wavebands. We employed the technique of difference image analysis to perform precision differential ...
  • CCD time-series photometry of variable stars in globular clusters and the metallicity dependence of the horizontal branch luminosity 
    Arellano Ferro, A; Bramich, D. M; Giridhar, S (Institute de Astronomia, 2017-04)
    We describe and summarize the findings from our CCD time-seri es photom- etry of globular clusters (GCs) program and the use of differe nce image analysis (DIA) in the extraction of precise light curves down to V ≈ 19 ...
  • Constraining the parameters of globular cluster NGC 1904 from its variable star population 
    Kains, N; Bramich, D. M; Figuera Jaimes, R; Arellano Ferro, A; Giridhar, S; Kuppuswamy, K (EDP Sciences, 2012-12)
    Aims. We present the analysis of 11 nights of V and I time-series observations of the globular cluster NGC 1904 (M 79). Using this we searched for variable stars in this cluster and attempted to refine the periods of known ...
  • A detailed census of variable stars in the globular cluster NGC 6333 (M9) from CCD differential photometry 
    Arellano Ferro, A; Bramich, D. M; Jaimes, R. F; Giridhar, S; Kains, N; Kuppuswamy, K; Jorgensen, U. G; Alsubai, K. A; Andersen, J. M; Bozza, V; Browne, P; Novati, S. C; Damerdji, Y; Diehl, C; Dominik, M; Dreizler, S; Elyiv, A; Giannini, E; Harpsoe, K; Hessman, F. V; Hinse, T. C; Hundertmark, M; Juncher, D; Kerins, E; Korhonen, H; Liebig, C; Mancini, L; Mathiasen, M; Penny, M. T; Rabus, M; Rahvar, S; Ricci, D; Scarpetta, G; Skottfelt, J; Snodgrass, C; Southworth, J; Surdej, J; Tregloan-Reed, J; Vilela, C; Wertz, O (Oxford University Press on behalf of the Royal Astronomical Society, 2013-09-11)
    We report CCD V and I time series photometry of the globular cluster NGC 6333 (M9). The technique of difference image analysis has been used, which enables photometric precision better than 0.05 mag for stars brighter than ...
  • Difference image analysis: extension to a spatially varying photometric scale factor and other considerations 
    Bramich, D. M; Horne, Keith; Albrow, M. D; Tsapras, Y; Snodgrass, C; Street, R. A; Hundertmark, M; Kains, N; Arellano Ferro, A; Figuera Jaimes, R; Giridhar, S (Oxford University Press on behalf of the Royal Astronomical Society, 2013-01-21)
    We present a general framework for matching the point-spread function (PSF), photometric scaling and sky background between two images, a subject which is commonly referred to as difference image analysis (DIA). We introduce ...
  • Estimating the parameters of globular cluster M 30 (NGC 7099) from time-series photometry 
    Kains, N; Bramich, D. M; Ferro, A. A; Jaimes, R. F; Jorgensen, U. G; Giridhar, S; Penny, M. T; Alsubai, K. A; Andersen, J. M; Bozza, V; Browne, P; Burgdorf, M; Novati, S. C; Damerdji, Y; Diehl, C; Dodds, P; Dominik, M; Elyiv, A; Fang, X.-S; Giannini, E; Gu, S.-H; Hardis, S; Harpsoe, K; Hinse, T. C; Hornstrup, A; Hundertmark, M; Jessen-Hansen, J; Juncher, D; Kerins, E; Kjeldsen, H; Korhonen, H; Liebig, C; Lund, M. N; Lundkvist, M; Mancini, L; Martin, R; Mathiasen, M; Rabus, M; Rahvar, S; Ricci, D; Sahu, D. K; Scarpetta, G; Skottfelt, J; Snodgrass, C; Southworth, J; Surdej, J; Tregloan-Reed, J; Vilela, C; Wertz, O; Williams, A (EDP Sciences, 2013-07)
    Aims. We present the analysis of 26 nights of V and I time-series observations from 2011 and 2012 of the globular cluster M 30 (NGC 7099). We used our data to search for variable stars in this cluster and refine the periods ...
  • Exploring the variable stars in the globular cluster NGC 5024 (M53): new RR Lyrae and SX Phoenicis stars 
    Arellano Ferro, A; Figuera Jaimes, R; Giridhar, S; Bramich, D. M; Hernández Santisteban, J. V; Kuppuswamy, K (Wiley-Blackwell, 2011-09)
    We report CCD V and I time series photometry of the globular cluster NGC 5024 (M53). The technique of difference image analysis has been used which enables photometric precisions better than 10 mmag for stars brighter than ...
  • Full orbital solution for the binary system in the northern Galactic disc microlensing event Gaia16aye 
    Wyrzykowski, L; Mroz, P; Rybicki, K. A; Gromadzki, M; Kolaczkowski, Z; Zielinski, M; Zielinski, P; Britavskiy, N; Gomboc, A; Sokolovsky, K; Hodgkin, S. T; Abe, L; Aldi, G. F; AlMannaei, A; Altavilla, G; Al Qasim, A; Anupama, G. C; Awiphan, S; Bachelet, E; Bakış, V; Baker, S; Bartlett, S; Bendjoya, P; Benson, K; Bikmaev, I. F; Birenbaum, G; Blagorodnova, N; Blanco-Cuaresma, S; Boeva, S; Bonanos, A. Z; Bozza, V; Bramich, D. M; Brun, I; Burenin, R. A; Burgaz, U; Butterley, T; Caines, H. E; Caton, D. B; Calchi Novati, S; Carrasco, J. M; Cassan, A; Cepas, V; Cropper, M; Chruslinska, M; Clementini, G; Clerici, A; Conti, D; Conti, M; Cross, S; Cusano, F; and 134 co-authors (EDP Sciences, 2020-01)
    Gaia16aye was a binary microlensing event discovered in the direction towards the northern Galactic disc and was one of the first microlensing events detected and alerted to by the Gaia space mission. Its light curve ...
  • Investigation of variable star candidates in the globular cluster NGC 5024 (M53) 
    Bramich, D. M; Arellano Ferro, A; Figuera Jaimes, R; Giridhar, S (Wiley-Blackwell, 2012-08)
    We have performed a careful investigation of the 74 candidate variable stars presented by Safonova & Stalin. For this purpose we used our data base of imaging and light curves from Arellano Ferro et al. We find that two ...
  • A new search for variable stars in the globular cluster NGC 6366 
    Ferro, A. A; Giridhar, S; Lopez, V. R; Figuera, R; Bramich, D. M; Rosenzweig, P (Instituto de Astronomía, 2008-10)
    New CCD photometry of NGC 6366 has lead to the discovery of some variable stars. Two possible Anomalous Cepheids (or Pop II Cepheids), three long period variables, one SX Phe and one eclipsing binary have been found. Also, ...
  • New variables in M5 (NGC 5904) and some identification corrections 
    Arellano Ferro, A; Bramich, D. M; Giridhar, S; Luna, A; Muneer, S (Konkoly Observatory, 2015-04)
    We report twelve variables not previously detected in the globular cluster M5 (NGC 5904); one SX Phe and eleven semi-regular variables (SR). Their identifications, equatorial coordinates, ephemerides, and light curves are ...
  • Physical parameters of RR Lyrae stars in the globular cluster NGC 5466: The Oosterhoff dichotomy 
    Rojas Lopez, V; Arellano Ferro, A; Giridhar, S; Bramich, D. M (Instituto de Astronomía, 2006-06)
    The highlights of CCD photometry of RR Lyrae stars in NGC 5466 are presented. The image subtraction method (Bramich et al. 2005) was used. The Fourier light curve decomposition, lead to an average [Fe/H]=-1.88+/-0.3 and a ...
  • Revisiting the variable star population in NGC 6229 and the structure of the horizontal branch 
    Arellano Ferro, A; Mancera Pina, P. E; Bramich, D. M; Giridhar, S; Ahumada, J. A; Kains, N; Kuppuswamy, K (Oxford University Press on behalf of the Royal Astronomical Society, 2015-09-01)
    We report an analysis of new V and I CCD time series photometry of the distant globular cluster NGC 6229. The principal aims were to explore the field of the cluster in search of new variables, and to Fourier decompose the ...
  • RR Lyrae stars and the horizontal branch of NGC 5904 (M5) 
    Ferro, A. A; Luna, A; Bramich, D. M; Giridhar, S; Ahumada, J. A; Muneer, S (Springer, 2016-05)
    We report the distance and [Fe/H] value for the globular cluster NGC 5904 (M5) derived from the Fourier decomposition of the light curves of selected RRab and RRc stars. The aim in doing this was to bring these ...
  • The unusually large population of Blazhko variables in the globular cluster NGC 5024 (M53) 
    Arellano Ferro, A; Bramich, D. M; Figuera Jaimes, R; Giridhar, S; Kuppuswamy, K (Wiley-Blackwell, 2012-02)
    We report the discovery of amplitude and phase modulations typical of the Blazhko effect in 22 RRc and nine RRab type RR Lyrae stars in NGC 5024 (M53). This brings the confirmed Blazhko variables in this cluster to 23 RRc ...
  • Variable stars in the globular cluster NGC 7492. New discoveries and physical parameter determination 
    Figuera Jaimes, R; Arellano Ferro, A; Bramich, D. M; Giridhar, S; Kuppuswamy, K (EDP Sciences, 2013-08)
    Aims. We have performed a photometric V,R,I CCD time-series analysis with a baseline of about eight years of the outer-halo globular cluster NGC 7492 with the aim of searching for new variables and using these (and the ...

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