J/AJ/117/247 Ages for globular clusters in the halo (Stetson+, 1999)
Ages for globular clusters in the outer galactic halo: the second-parameter
clusters Palomar 3, Palomar 4, and Eridanus
Stetson P.B., Bolte M., Harris W.E., Hesser J.E., Van den Bergh S.,
Vandenberg D.A., Bell R.A., Johnson J.A., Bond H.E., Fullton L.K.,
Fahlamn G.G., Richer H.B.
<Astron. J. 117, 247 (1999)>
=1999AJ....117..247S 1999AJ....117..247S
ADC_Keywords: Clusters, globular ; HR diagrams ; Photometry
Mission_Name: HST
Keywords: Galaxy: formation - globular clusters: individual (Palomar 3,
Palomar 4, Eridanus)
Abstract:
We have used the Wide Field Planetary Camera 2 on the Hubble Space
Telescope to obtain photometry of the outer halo globular clusters
Palomar 3, Palomar 4, and Eridanus. These three are classic examples
of the "second-parameter" anomaly because of their red
horizontal-branch morphologies in combination with their
low-to-intermediate metallicities. Our color-magnitude diagrams (CMDs)
in V, V - I reach Vlim ≃ 27.0, clearly delineating the subgiant
and turnoff regions and about 3 mag of the unevolved main sequences.
Description:
Palomar 3 and Palomar 4 were imaged with the Wide Field Planetary
Camera 2 (WFPC2) camera during HST Cycle 4, with Palomar 4 being
visited twice. Eridanus was observed during Cycle 5. The nearby halo
clusters M3 and M5 were observed from ground-based telescopes. Data
for M3 were obtained during seven observing runs on four different
telescopes between 1983 and 1994 (although the I-band data came from
only two of those runs), while M5 was observed during twelve runs on
six different telescopes during the same time span (again the I-band
data were from two of those runs).
Objects:
---------------------------------------------------
RA (2000) DE Designation(s)
---------------------------------------------------
10 05 31.3 +00 04 17 Palomar 3 = C 1003+003
11 29 16.8 +28 58 25 Palomar 4 = C 1126+292
04 24 44.5 -21 11 13 Eridanus = C 0422-213
13 42 11.2 +28 22 32 M3 = NGC 5272 = C 1339+286
15 18 33.7 +02 04 58 M5 = NGC 5904 = C 1516+022
---------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 64 216 Normal points for program clusters
--------------------------------------------------------------------------------
See also:
II/37 : UBV HR Diagrams of Globular Clusters (Philip+ 1976)
II/117 : Catalog of UBVRI Photometry of Globular Clusters (Peterson 1986)
VII/103 : Catalogue of galactic globular clusters
J/A+A/320/757 : M3 stars CCD photometry (Ferraro+ 1997)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Name Globular cluster name
13- 18 F6.3 mag Vmag Mean V band magnitude of stars found in
each bin
22- 26 F5.3 mag e_Vmag Uncertainty in Vmag
30- 34 F5.3 mag V-I Mean V-I color of stars found in each bin
38- 42 F5.3 mag e_V-I Uncertainty in V-I
46- 48 I3 --- Iter1 Number of stars per bin retained in the
1st iteration of σ-clipping
54- 56 I3 --- Iter2 Number of stars per bin retained in the
2nd iteration of σ-clipping
62- 64 I3 --- Iter3 Number of stars per bin retained in the
3rd iteration of σ-clipping
--------------------------------------------------------------------------------
History:
From AJ electronic edition
(End) Greg Schwarz [AAS] 06-Apr-2000