J/MNRAS/433/1966 Segue 3 VI photometry (Ortolani+, 2013)
Segue 3: the youngest globular cluster in the outer halo.
Ortolani S., Bica E., Barbuy B.
<Mon. Not. R. Astron. Soc., 433, 1966-1969 (2013)>
=2013MNRAS.433.1966O 2013MNRAS.433.1966O
ADC_Keywords: Clusters, globular ; Photometry, VRI
Keywords: Hertzsprung-Russell and colour-magnitude diagrams -
globular clusters: individual: Segue 3 - Galaxy: halo
Abstract:
Deep Galileo (Telescopio Nazionale Galileo) B, V and I images of
Segue 3, reaching V∼25, reveal that it is the youngest globular
cluster known so far in the Galaxy. A young age of 3.2Gyr is found,
differently from a previous estimate of 12Gyr. It also appears to be
moderately metal rich with [Fe/H]~-0.8, rather than [Fe/H]~-1.7, as
previously suggested by Fadely et al. (2011AJ....142...88F 2011AJ....142...88F, Cat.
J/AJ/142/88). A main difference in the age derivation relative to
Fadely et al. comes from the consideration of subgiant branch stars in
the isochrone fitting. A deduced distance of d☉=29.1kpc is
compatible with the outer halo location of other low luminosity
globular clusters.
Description:
Johnson-Cousins V and I images were obtained at the Telescopio
Nazionale Galileo (TNG), equipped with the spectrograph/focal reducer
DOLORES, with a 2000x2000-pixels of 8.5x8.5-arcmin2 CCD giving
0.25arcsec/pix, during the night of 2011 June 26-27. Additional B, V
and I photometry was obtained, with the same equipment, in the night
of 2012 June 17-18.
Objects:
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RA (2000) DE Designation(s)
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21 21 31.0 +19 07 02 Name Segue 3 = NAME Segue 3
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
seg3viac.dat 53 1103 Segue 3 V and I photometry (long exposure)
seg3vibc.dat 43 243 Segue 3 V and I photometry (short exposure)
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See also:
J/AJ/142/88 : Segue 3 photometric and kinematic data (Fadely+, 2011)
Byte-by-byte Description of file: seg3viac.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Seq [1/1248] Sequential number within the table
6- 16 E11.6 --- Xpos [0/2009] X position (LAB002_A)
18- 28 E11.6 --- Ypos [0/2009] Y position (LAB003_A)
30- 41 E12.6 mag V-I Johnson-Cousins V-I colour index
43- 53 E11.6 mag Vmag [20.1/25.9] Johnson V magnitude
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Byte-by-byte Description of file: seg3vibc.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [4/431] Sequential number within the table
5- 11 F7.2 pix Xpos [0/2009] X position
13- 19 F7.2 pix Ypos [0/2009] Y position
21- 31 E11.6 mag V-I Johnson-Cousins V-I colour index
33- 43 E11.6 mag Vmag [14.4/20.1] Johnson V magnitude
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 09-Jan-2015