J/A+A/319/850 V, I , and Gunn z imaging of Terzan 4 (Ortolani+ 1997)
High quality seeing V, I, and Gunn z imaging of Terzan 4: a blue horizontal
branch bulge globular cluster
Ortolani S., Barbuy B., Bica E.
<Astron. Astrophys. 319, 850 (1997)>
=1997A&A...319..850O 1997A&A...319..850O (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Photometry
Keywords: globular clusters: individual: Terzan 4, M 30; general - HR diagram -
Galaxy: center
Abstract:
We study the globular cluster Terzan 4 projected close to the Galactic
center, by means of V, I and Gunn z Colour-Magnitude Diagrams. The
images were obtained under exceptional seeing conditions (0.35"-0.55")
at the ESO New Technology Telescope equipped with SUSI. We derive a
reddening of E(B-V)=2.35 and a distance from the Sun d☉=8.3kpc
for Terzan 4. From the similarity of the VI Colour-Magnitude Diagrams
of Terzan 4 and M30, in particular the presence of a blue horizontal
branch, it could be as metal-poor as [Fe/H]≃-2.0. It is therefore
another blue horizontal branch globular cluster located close to the
Galactic center.
Objects:
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RA (2000) DE Designation(s)
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17 30 38 -31 35.8 Terzan 4 = C 1727-315
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
ter4iz 36 10280 I, Gunn z photometry of Terzan 4
ter4vi 36 2078 V, I photometry of Terzan 4
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Byte-by-byte Description of file: ter4vi
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Bytes Format Units Label Explanations
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1- 5 I5 --- Seq Sequence number
7- 13 F7.2 pix Xpos x pixel coordinate in Fig. 1
15- 21 F7.2 pix Ypos y pixel coordinate in Fig. 1
23- 28 F6.3 mag Vmag ? V magnitude
30- 36 F7.3 mag V-I ? V-I color index
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Byte-by-byte Description of file: ter4iz
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Bytes Format Units Label Explanations
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1- 5 I5 --- Seq Sequence number
7- 13 F7.2 pix Xpos x pixel coordinate in Fig. 1
15- 21 F7.2 pix Ypos y pixel coordinate in Fig. 1
23- 28 F6.3 mag Imag ? I magnitude
30- 36 F7.3 mag I-z ? I-z color index
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Acknowledgements: Beatriz Barbuy
(End) Patricia Bauer [CDS] 25-Sep-1996