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J/ApJ/591/L111      Period of Cepheids in M 83               (Bonanos+, 2003)

Reanalysis of Very Large Telescope data for M83 with image subtraction-Ninefold increase in number of Cepheids. Bonanos A.Z., Stanek K.Z. <Astrophys. J. 591, L111 (2003)> =2003ApJ...591L.111B
ADC_Keywords: Stars, variable Keywords: Cepheids - distance scale - galaxies: individual (M83) Abstract: We apply the image-subtraction method in order to reanalyze the ESO Very Large Telescope data on M83 (NGC 5236), obtained and analyzed by Thim et al. (2003ApJ...590..256T). Whereas Thim et al. (2003ApJ...590..256T) found 12 Cepheids with periods between 12 and 55 days, we find 112 Cepheids with periods ranging from 7 to 91 days as well as 60 other variables. These include two candidate eclipsing binaries, which, if confirmed, would be the first optically discovered outside the Local Group. We thus demonstrate that the image-subtraction method is much more powerful for detecting variability, especially in crowded fields. However, Hubble Space Telescope observations are necessary to obtain a Cepheid period-luminosity distance not dominated by blending and crowding. We propose a "hybrid" approach, in which numerous Cepheids are discovered and characterized using large ground-based telescopes and then followed up with the Hubble Space Telescope to obtain precise distances. Description: We have retrieved the M83 data obtained by the FOcal Reducer/low dispersion Spectrograph 1 (FORS1) on the ESO VLT, from the ESO/Space Telescope-European Coordinating Facility (ST-ECF) Science Archive. The field of view is 6.8'x6.8', with a pixel scale of 0.2"/pix. The 2048x2048 Tektronix CCD has 24µm pixels. There are 34 epochs in the V band spanning a period of 1.5yr, from 2000 January to 2001 July. Each epoch consists of three to four subexposures of 400 or 500s. More details are given by Thim et al. (2003ApJ...590..256T). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 62 112 Cepheids in M83
Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 2 I2 h RAh Hour of Right Ascension (J2000) 4- 5 I2 min RAm Minute of Right Ascension (J2000) 7- 10 F4.1 s RAs Second of Right Ascension (J2000) 12 A1 --- DE- Sign of the Declination (J2000) 13- 14 I2 deg DEd Degree of Declination (J2000) 16- 17 I2 arcmin DEm Arcminute of Declination (J2000) 19- 22 F4.1 arcsec DEs Arcsecond of Declination (J2000) 24- 29 F6.3 d Per Period 31- 37 F7.2 pix Xpix The X pixel coordinate on the reference image 39- 45 F7.2 pix Ypix The Y pixel coordinate on the reference image 47- 61 A15 --- Comm Additional comments (1)
Note (1): Names and periods of Cepheids found by Thim et al., 2003ApJ...590..256T.
Nomenclature Notes: Objects are identified as [BS2003] JHHMMSS.s+DDMMSS.s in Simbad History: From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 26-Sep-2003
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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