J/MNRAS/349/1278 BVI photometry of M22 (Monaco+, 2004)
Wide-field photometry of the Galactic globular cluster M22.
Monaco L., Pancino E., Ferraro F.R., Bellazzini M.
<Mon. Not. R. Astron. Soc., 349, 1278-1290 (2004)>
=2004MNRAS.349.1278M 2004MNRAS.349.1278M
ADC_Keywords: Clusters, globular ; Photometry, CCD
Keywords: globular clusters: individual: M 22 -
planetary nebulae: individual: IRAS 18333-2357
Abstract:
We present wide field photometry of the Galactic Globular Cluster M 22
in the B, V and I passbands for more than 186,000 stars. The study is
complemented by the photometry in two narrowband filters centered on
Hα and the adjacent continuum, and by infrared J, H and K
magnitudes derived from the 2 MASS survey for ∼2000 stars. Profiting
from this huge database, we completely characterized the evolved
stellar sequences of the cluster by determining a variety of
photometric parameters, including new photometric estimates of the
mean metallicity, reddening and distance to the cluster. In
particular, from our multi-wavelength analysis, we re-examined the
long-standing metallicity spread problem in M 22. According to our
dataset, we conclude that most of the observed width of the red giant
branch must be due to differential reddening, which amounts to a
maximum of ΔE(B-V)∼0.06, although the presence of a small
metallicity spread cannot be completely ruled out. More specifically,
the maximum metallicity spread allowed by our data is of the order of
Δ[Fe/H]∼0.1-0.2dex, i.e., not much more than what allowed by the
photometric errors. Finally, we identified most of the known variable
stars and peculiar objects in our field of view. In particular, we
find additional evidence supporting previous optical identifications
of the central star of the Planetary Nebula IRAS 18333-2357, which is
associated with M 22.
Description:
B, V, I band photometry and coordinates for stars in the galactic
globular cluster M22. Star positions are provided both in the pixel
coordinate system of each CCD and in the equatorial coordinate system.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
chip1.dat 101 22835 Photometry of stars in Chip #1
chip2.dat 101 33785 *Photometry of stars in Chip #2
chip3.dat 101 24336 Photometry of stars in Chip #3
chip6.dat 101 20562 Photometry of stars in Chip #6
chip7.dat 101 20673 Photometry of stars in Chip #7
chip8.dat 101 19786 Photometry of stars in Chip #8
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Note on chip2.dat: The cluster has been centered on chip #2. Therefore,
the file contains the photometry for most of the cluster population.
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See also:
J/ApJ/420/612 : Proper motions + radial velocities in M22 (Peterson+ 1994)
J/A+AS/109/487 : Color-magnitude study of M 22 (Samus+, 1995)
Byte-by-byte Description of file: chip?.dat
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Bytes Format Units Label Explanations
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2- 6 I5 --- MPF Star Sequencial Identifier,
Cl* NGC 6656 MPF NNNN in Simbad
10- 15 F6.3 mag Bmag B-band magnitude
19- 23 F5.3 mag e_Bmag Formal DAOPHOT errors associated to the B-band
magnitude
26- 31 F6.3 mag Vmag V-band magnitude
35- 39 F5.3 mag e_Vmag Formal DAOPHOT errors associated to the V-band
magnitude
42- 47 F6.3 mag Imag I-band magnitude
51- 55 F5.3 mag e_Imag Formal DAOPHOT errors associated to the I-band
magnitude
58- 65 F8.3 pix xpos x star coordinates in the pixel coordinate system
68- 75 F8.3 pix ypos y star coordinates in the pixel coordinate system
78- 88 F11.7 deg RAdeg Right Ascension J2000 (decimal degrees)
91-101 F11.7 deg DEdeg Declination J2000 (decimal degrees)
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Acknowledgements: L. Monaco
(End) Patricia Bauer [CDS] 29-Apr-2004