J/ApJ/654/915 Deep FORS1 BR photometry of omega Cen (Sollima+, 2007)
Deep FORS1 observations of the double Main Sequence of omega Centauri.
Sollima A., Ferraro F.R., Bellazzini M., Origlia M., Straniero O.,
Pancino E.
<Astrophys. J. 654, 915-922 (2007)>
=2007ApJ...654..915S 2007ApJ...654..915S
ADC_Keywords: Clusters, globular ; Photometry, UBVRI ; Stars, population II
Keywords: globular clusters: individual (omega Centauri) - stars: evolution -
stars: Population II - techniques: photometric
Abstract:
We present the results of a deep photometric survey performed with the
VLT FORS1 aimed at investigating the complex main-sequence structure
of the stellar system Centauri. We confirm the presence of a double
main sequence and identify its blue component (bMS) over a large field
of view up to 26' from the cluster center. We found that bMS stars are
significantly more concentrated toward the cluster center than the
other "normal" MS stars. The bMS morphology and its position in the
CMD have been used to constrain the helium overabundance required to
explain the observed MS morphology.
Description:
This catalog is based on a deep photometric survey performed in the
field of the stellar system omega Centauri with FORS1@VLT, during 6
nights on 2005 March and April. It consists in a mosaic of eight
partially overlapping filed covering a wide area from 6' to 26' from
the cluster center. The magnitudes of more than 70,000 stars have been
measured in the B and R photometric bands. The limiting magnitude is
R<24 and the positional accuracy is better than 0.2" for ∼99% of the
stars.
Objects:
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RA (2000) DE Designation(s)
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13 26 45.9 -47 28 37 * ome Cen = NGC 5139
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fors1.dat 71 66618 ω Cen BR catalog
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See also:
J/MNRAS/250/314 : CCD photometry of omega Cen (Noble+ 1991)
J/AJ/108/1350 : Omega Cen FUV photometry (Whitney+, 1994)
J/PASP/106/828 : BVRI photometry of Omega Cen (Walker 1994)
J/A+AS/115/297 : BVRI photometry of Central Field of Omega Cen (Lynga+, 1996)
J/AJ/127/958 : CCD BV photometry on Omega Cen (Rey+, 2004)
Byte-by-byte Description of file: fors1.dat
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Bytes Format Units Label Explanations
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3- 7 I5 --- Seq [1/66618] Sequential number
10- 16 F7.4 mag Bmag ?=0.0000 Bessel B magnitude
20- 25 F6.4 mag e_Bmag ?=0.000 Mean error on B magnitude
28- 34 F7.4 mag Rmag ?=0.0000 Bessel R magnitude
38- 43 F6.4 mag e_Rmag ?=0.000 Mean error on R magnitude
46- 57 F12.8 deg RAdeg Right Ascension J2000 (degrees)
60- 71 F12.8 deg DEdeg Declination J2000 (degrees)
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Acknowledgements:
Antonio Sollima, antonio.sollima(at)bo.astro.it
(End) Patricia Vannier [CDS] 12-Jan-2007