J/A+A/448/171 BV photometry of 3 globular clusters (Hilker+, 2006)
Probable member stars of the gravitational theory-testing globular clusters
AM 1, Pal 3 and Pal 14.
Hilker M.
<Astron. Astrophys., 448, 171-180 (2006)>
=2006A&A...448..171H 2006A&A...448..171H
ADC_Keywords: Clusters, globular ; Photometry, UBV
Keywords: Galaxy: globular clusters: individual: AM 1, Pal 3, Pal 14 -
astrometry - Galaxy: kinematics and dynamics
Abstract:
Some of the Galactic outer halo globular clusters are excellent tools
to probe gravitational theories in the regime of weak accelerations.
The measurement of the line-of-sight velocity dispersion among stars
in these clusters will differentiate between the validity of Newtonian
dynamics (low velocity dispersion) and the possibility of modified
Newtonian dynamics (MOND) or dark matter dominated globular clusters
(high velocity dispersion). In this paper, the properties of probable
member stars of the three best-case gravitational theory-testing
clusters AM 1, Pal 3 and Pal 14 are presented. The member selection is
based on VLT photometry in Johnson BV. The positions of the stars were
determined with an accuracy of the order of ≤0.2", allowing their
direct use for follow-up spectroscopy. The distance, reddening, age
and metallicities of the clusters were estimated from isochrone
fitting. Furthermore, improved structural parameters, like central
coordinates, ellipticity, half-light radius, King model core and tidal
radius, are presented.
Description:
The observations were performed in February 2005 with the VLT/UT1 at
Paranal (ESO), Chile. The instrument in use was the FORS2 camera with
a 4x4 k MIT CCD array attached. The data were read out with a 2x2
binning, resulting in a spatial scale of 0.25"/pixel and a field of
view of 6.8'x6.8'.
Objects:
----------------------------------------------------------
RA (2000) DE Designation(s) (file)
----------------------------------------------------------
03 55 02.7 -49 36 52 Cl AM 1 = ESO 201- 10 (tablea1)
10 05 31.0 +00 04 15 Cl Pal 3 = UGC 5439 (tablea2)
16 10 59.0 +14 57 42 Cl Pal 14 = GCl 38 (tablea3)
----------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 57 110 List of probable member stars of AM 1, ordered
by increasing V magnitude.
tablea2.dat 58 153 List of probable member stars of Pal 3, ordered
by increasing V magnitude.
tablea3.dat 58 143 List of probable member stars of Pal 14, ordered
by increasing V magnitude
--------------------------------------------------------------------------------
See also:
J/AJ/117/247 : Ages for globular clusters in the halo (Stetson+, 1999)
Byte-by-byte Description of file: tablea?.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq Sequential number (1)
5- 6 I2 h RAh Right ascension (J2000)
8- 9 I2 min RAm Right ascension (J2000)
11- 15 F5.2 s RAs Right ascension (J2000)
17 A1 --- DE- Declination sign (J2000)
18- 19 I2 deg DEd Declination (J2000)
21- 22 I2 arcmin DEm Declination (J2000)
24- 27 F4.1 arcsec DEs Declination (J2000)
29- 33 F5.2 mag Vmag V magnitude from PSF fit
35- 38 F4.2 mag B-V B-V colour index
40- 43 F4.2 mag e_Vmag rms uncertainty on Vmag
45- 48 F4.2 mag e_Bmag rms uncertainty on Bmag
50- 53 F4.2 arcmin Rad Projected distance to cluster center
55- 58 A4 --- Type Part of the CMD the star probably belongs (2)
--------------------------------------------------------------------------------
Note (1): Stars are identified as Cl* AM 1 H NNN, Cl* Palomar 3 H NNN and
Cl* Palomar 4 H NNN in Simbad, respectively.
Note (2): region of the colour-magnitude diagram abbreviated as:
RGB = red giant branch,
HB = horizontal branch,
AGB = asymptotic giant branch
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 17-Nov-2006