J/AJ/127/2210 u'g'r'i'z' photometry in NGC 2548 (M48) (Rider+, 2004)
A survey of open clusters in the u'g'r'i'z' filter system.
I. Results for NGC 2548 (M48).
Rider C.J., Tucker D.L., Smith J.A., Stoughton C., Allam S.S.,
Neilsen E.H.JR
<Astron. J., 127, 2210-2227 (2004)>
=2004AJ....127.2210R 2004AJ....127.2210R
ADC_Keywords: Clusters, open ; Photometry, SDSS
Keywords: Hertzsprung-Russell diagram -
open clusters and associations: individual (NGC 2548) -
stars: abundances
Abstract:
We present initial results of a photometric survey of open star
clusters, primarily in the southern hemisphere, taken in the
u'g'r'i'z' filter system. While our entire observed sample covers more
than 100 clusters, here we present data for NGC 2548 (M48), which is a
cluster characterized in the UBV and DDO photometric systems. We
compare our results to the published values from other observers and
to the Padova theoretical isochrones and metallicity curves. These
observations demonstrate that the u'g'r'i'z' filters can play an
important role in determining the metallicity of stars and clusters.
We begin this series of papers with a study of NGC 2548 because we
have obtained data on this cluster not only with our main program
telescope, the CTIO Curtis Schmidt, but also with the US Naval
Observatory (USNO) 1.0m telescope (the telescope used to define the
u'g'r'i'z' system), and with the Sloan Digital Sky Survey (SDSS) 0.5m
Photometric Telescope (the photometric monitoring telescope used to
calibrate the SDSS 2.5m telescope imaging data). We have used the data
from this study to validate our ability to transform measurements
obtained on other telescopes to the standard USNO 1.0m u'g'r'i'z'
system. This validation is particularly important for very red stars,
for which the original u'g'r'i'z' standard star network is poorly
constrained.
Description:
The five filters of the u'g'r'i'z' system have effective wavelengths
of 3540, 4750, 6222, 7632, and 9049Å, respectively, at 1.2 air
masses. Observations on USNO 1.0m Telescope were made on 2002 Nov 5-6,
observations on SDSS Photometric Telescope were made on 2001 Dec 02
and observations on CTIO Curtis Schmidt Telescope were made on 2000
Mar 06.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table4.dat 133 381 Data from the USNO 1.0m Telescope
table5.dat 133 1353 Data from the Photometric Telescope
table6.dat 133 2520 Data from the CTIO Curtis Schmidt Telescope
--------------------------------------------------------------------------------
See also:
J/A+A/381/464 : Proper motions and membership in NGC 2548 (Wu+, 2002)
Byte-by-byte Description of file: table4.dat table5.dat table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- RTS Internal identification number,
Cl* NGC 2548 RTS NNNN in Simbad
6- 9 I4 --- WEBDA ?=-1 WEBDA database identification number
11- 12 I2 h RAh Hour of right ascension (J2000)
14- 15 I2 min RAm Minute of right ascension (J2000)
17- 20 F4.1 s RAs Second of right ascension (J2000)
22 A1 --- DE- Sign of the declination (J2000)
23- 24 I2 deg DEd Degree of declination (J2000)
26- 27 I2 arcmin DEm Arcminute of declination (J2000)
29- 30 I2 arcsec DEs Arcsecond of declination (J2000)
32- 39 F8.3 mag u'mag ?=-100.000 The u' band AB magnitude (1)
41- 48 F8.3 mag g'mag ?=-100.000 The g' band AB magnitude (1)
50- 57 F8.3 mag r'mag ?=-100.000 The r' band AB magnitude (1)
59- 66 F8.3 mag i'mag ?=-100.000 The i' band AB magnitude (1)
68- 75 F8.3 mag z'mag ?=-100.000 The z' band AB magnitude (1)
77- 84 F8.3 mag e_u'mag ?=-100.000 Photon noise error in u'mag (1)
86- 93 F8.3 mag e_g'mag ?=-100.000 Photon noise error in g'mag (1)
95-102 F8.3 mag e_r'mag ?=-100.000 Photon noise error in r'mag (1)
104-111 F8.3 mag e_i'mag ?=-100.000 Photon noise error in i'mag (1)
113-120 F8.3 mag e_z'mag ?=-100.000 Photon noise error in z'mag (1)
122 I1 --- f_u'mag [0/1] Saturation flag on u'mag (2)
124 I1 --- f_g'mag [0/1] Saturation flag on g'mag (2)
126 I1 --- f_r'mag [0/1] Saturation flag on r'mag (2)
128 I1 --- f_i'mag [0/1] Saturation flag on i'mag (2)
130 I1 --- f_z'mag [0/1] Saturation flag on z'mag (2)
132-133 I2 % Prob ?=-1 Proper-motion membership probability (3)
--------------------------------------------------------------------------------
Note (1): Photon noise error:
-100 = Either saturation or no detection.
Note (2): Saturation flag as follows:
1 = Either no detection or saturation.
Note (3): From Dias, Lepine, and Alessi, 2001, Cat. J/A+A/376/441.
-1 = No membership information for that star.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) James Marcout, Patricia Vannier [CDS] 06-Jul-2004