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J/PASP/111/812  V(RI)C Phot of Cepheids in the Magellanic Clouds (Barnes+ 1999)

V(RI)C Photometry of Cepheids in the Magellanic Clouds Barnes T. G. III, Ivans I. I., Martin J. R., Froning C. S., Moffett T. J. <Publ. Astron. Soc. Pac., 111, 812 (1999)> =1999PASP..111..812B
ADC_Keywords: Stars, variable; Magellanic Clouds; Photometry, Cousins Keywords: Cepheids, Magellanic Clouds, stars: fundamental parameters Abstract: We present V(RI)C data for 13 Cepheids in the Large Magellanic Cloud and eight in the Small Magellanic Cloud. The total number of new measures is 55 in each wavelength band. The median uncertainty in the photometry is 0.03 mag. These results supplement a larger photometric program presented in the second paper in this series which contained 1000 measures (0.01 mag) in each wavelength band on 22 variables with periods in the range 8133 days. Description: This is the fourth paper in a program to determine distances to the Large and Small Magellanic Clouds using the visual surface brightness technique. This technique provides Cepheid distances which are essentially independent of reddening and are independent of the period-luminosity-color relation and its calibration. The visual surface brightness technique requires radial velocities and photometric values of high quality. Fortunately, there are velocity curves for 14 LMC and eight SMC Cepheids from the work of the CORAVEL group (Imbert et al. 1985A&AS...61..259I, 1989A&AS...81..339) and from Caldwell et al. (1986MNRAS.220..671C). On the other hand, existing BV(RI)C photometry of these stars (Caldwell et al. 1986MNRAS.220..671C; Caldwell & Coulson 1986) samples the light curves too sparsely for our analysis, hence our present program to improve the available photometry. In Paper I (Barnes, Moffett, & Gieren 1993ApJ...405L..51B) we demonstrated the surface brightness technique for distance determination on HV 829 in the SMC using preliminary photometric data. For HV 829 we obtained a distance modulus of 18.9±0.2 mag. Because HV 829 may not lie at the centroid of the SMC, this may not be the mean distance to the SMC. In Paper II (Moffett, Gieren, & Barnes 1998ApJS..117..135M) we presented new Cousins BV(RI)C photometry of 14 Magellanic Cloud Cepheids and eight Small Magellanic Cloud Cepheids which yielded light curves of high quality, consistent with the quality of the radial velocity curves and sufficient for surface brightness analysis. In Paper III (Gieren, Moffett, & Barnes 1999ApJ...512..553G) we used the new photometry and existing radial velocities to determine radii for 16 Magellanic Cloud Cepheids and to compare those radii with results for Galactic Cepheids. In this paper we present additional Cousins V(RI)C photometric data for all but one of the stars in Paper II. The present data were actually the first to be obtained in our CCD observing program, but because the observing program shifted to another telescope for all subsequent runs, the present data became "orphaned" and have only now been reduced for publication. A follow-up paper will use the full set of photometry to determine individual Cepheid distances from the visual surface brightness technique. These data are also useful for other distance techniques, e.g., the infrared flux method. Table1.dat gives our photometric results. Separate Julian Dates are given for each passband because of the long integration times in some of the exposures. The magnitude uncertainty given for each Cepheid is the standard deviation in the comparison star values on the appropriate image. Because comparison star magnitudes (on the Cousins system) were adopted from Paper II, the scatter in their individual measures about the adopted means is a reasonable representation of the uncertainty in a single stellar magnitude measurement on that image, incorporating the errors in magnitude determination, atmospheric extinction, and transformation to the standard system. The Cepheid was almost always the brightest star on the image, making the quoted uncertainties conservative estimates. The median standard deviation in the comparison star measures is 0.043 mag in V, 0.033 mag in RC, and 0.034 mag in IC. A check on how well the present photometry fits the photometric system of Paper II was made by comparing the values in Table1.dat to the light curves in Paper II. We formed a difference (Table1.dat minus Paper II) for all measures in Table1.dat which fell within 0.02 in phase to a value in Paper II. Based on 35 differences, we found V = 0.006 0.050 mag, R = 0.009 0.034 mag, and I = 0.005±0.034 mag. The current photometry clearly matches the V(RI)C photometric system of Paper II. This is also illustrated in Figure 1 of the original source reference. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 99 55 Photometry of Magellanic Cloud Cepheids
See also: http://www.physics.mcmaster.ca/Cepheid/ : McMaster Cepheid Photometry and Radial Velocity Data Archive Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 3 A3 --- Galaxy SMC or LMC 5- 12 A8 --- Name Cepheid 14- 24 F11.3 d HJD_V V heliocentric Julian date 26- 31 F6.3 mag Vmag V magnitude 33- 37 F5.3 mag e_Vmag Uncertainty in V 39- 49 F11.3 d HJD_R(c) Rc heliocentric Julian date 51- 56 F6.3 mag R(c) R-c_ magnitude 58- 62 F5.3 mag e_R(c) Uncertainty in R_c 64- 74 F11.3 d HJD_I(c) Ic heliocentric Julian date 76- 81 F6.3 mag I(c) Ic magnitude 83- 87 F5.3 mag e_I(c) Uncertainty in Ic 89- 93 F5.3 mag V-R V-R color 95- 99 F5.3 mag V-I V-I color
References: Barnes, T. G., & Moffett, T. J. 1979, PASP, 91, 289 =1979PASP...91..289B Barnes, T. G., Moffett, T. J., & Gieren, W. P. 1993, ApJ, 405, L51 (Paper I) =1993ApJ...405L..51B Caldwell, J. A. R., & Coulson, I. M. 1986, South African Astron. Obs. Circ., 8, 1 Caldwell, J. A. R., Coulson, I. M., Spencer Jones, J. H., Black, C. A., & Feast, M. W. 1986, MNRAS, 220, 671 =1986MNRAS.220..671C Gieren, W. P., Moffett, T. J., & Barnes, T. G. 1999, ApJ, 512, 553 (Paper III) =1999ApJ...512..553G Imbert, M., et al. 1985, A&AS, 61, 259 =1985A&AS...61..259I Imbert, M. 1989, A&AS, 81, 339 =1989A&AS...81..339 Landolt, A. U. 1992, AJ, 104, 340 =1992AJ....104..340L Moffett, T. J., Gieren, W. P., & Barnes, T. G. 1998, ApJS, 117, 135 (Paper II) =1998ApJS..117..135M Stetson, P. B. 1987, PASP, 99, 191 =1987PASP...99..191S Tody, D. 1993, in ASP Conf. Ser. 52, Astronomical Data Analysis Software and Systems II, ed. R. J. Hanisch, R. J. V. Brissenden, & J. Barnes (San Francisco: ASP), 173
(End) Gail L. Schneider [SSDOO/ADC] 15-May-2000
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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