J/MNRAS/356/647 NGC 6404 and 6583 VI photometry (Carraro+, 2005)
NGC 6404 and 6583: two neglected intermediate-age open clusters located in the
Galactic Centre direction.
Carraro G., Mendez R.A., Costa E.
<Mon. Not. R. Astron. Soc., 356, 647-653 (2005)>
=2005MNRAS.356..647C 2005MNRAS.356..647C
ADC_Keywords: Clusters, open ; Photometry
Keywords: Hertzsprung-Russell (HR) diagram -
open clusters and associations: general -
open clusters and associations: individual: NGC 6404 -
open clusters and associations: individual: NGC 6583
Abstract:
We report on VI charge-coupled device photometry of two fields centred
in the region of the open clusters NGC 6404 and 6583 down to V=22.0.
So far these clusters have never been studied, and we provide for the
first time estimates of their fundamental parameters, namely, radial
extent, age, distance and reddening. We find that the radius of NGC
6404 is 2.0-arcmin, as previously proposed, while the radius of NGC
6583 is 1.0 arcmin, significantly lower than previous estimates. Both
clusters turn out to be of intermediate age (0.5-1.0Gyr old), and
located inside the solar ring, at a Galactocentric distance of about
6.5kpc. These results make these objects very interesting targets for
spectroscopic follow-up to measure their metallicity. In fact, they
might allow us to enlarge by more than 1 kpc the baseline of the
radial abundance gradient in the Galactic disc towards the Galactic
Centre direction. This baseline is currently rather narrow especially
for clusters of this age.
Description:
Charge-coupled device (CCD) VI observations were carried out with the
eight CCDs mosaic camera on the 1.3-m Warsaw Telescope at Las Campanas
Observatory (Chile), on the nights of 2004 July 2 to 4. The two
clusters were centred in chip 3. With a pixel size of 0.26 arcsec and
a CCD size of 4096x2048 pixels, this samples a 17.7x8.9 arcmin2
field in the sky. However, we trimmed the CCD and ultimately used in
this study an actual area of 13.7x8.9 arcmin2.
Objects:
-----------------------------------------------------
RA (2000) DE Designation(s)
-----------------------------------------------------
17 39 37 -33 14 48 NGC 6404 = Cl VDBH 240
18 15 49 -22 08 12 NGC 6583 = C 1812-221
-----------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
ngc6404.dat 65 24295 NGC6404 VI magnitudes
ngc6583.dat 65 26086 NGC6583 VI magnitudes
--------------------------------------------------------------------------------
See also:
B/ocl : Optically visible open clusters and Candidates (Dias+ 2002-13)
J/A+A/523/A11 : Open clusters towards the Galactic center (Magrini+, 2010)
Byte-by-byte Description of file: ngc6404.dat ngc6583.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I5 --- Seq Sequential number, within the cluster
8- 15 F8.3 pix Xpos X position (1)
18- 25 F8.3 pix Ypos Y position (1)
29- 35 F7.4 mag Vmag V magnitude
40- 45 F6.4 mag e_Vmag rms uncertainty on Vmag
49- 55 F7.4 mag Imag I magnitude
60- 65 F6.4 mag e_Imag rms uncertainty on Imag
--------------------------------------------------------------------------------
Note (1): North is up, east on the left, and the field is centred at the
cluster's nominal centre (scale 0.26arcsec/pix)
--------------------------------------------------------------------------------
History:
Copied at http://www.univie.ac.at/webda/archive_ngc.html
(End) Patricia Vannier [CDS] 25-Sep-2013