J/MNRAS/514/1122 Globular Cluster UVIT Legacy Survey (GlobULeS) (Sahu+, 2022)
Globular Cluster UVIT Legacy Survey (GlobULeS).
I. FUV-optical colour-magnitude diagrams for eight globular clusters.
Sahu, S., Subramaniam A., Singh G., Yadav R., Valcarce A.R., Choudhury S.,
Rani S., Prabhu D.S., Chung C., Cote P., Leigh N., Geller A.M.,
Chatterjee S., Rao N.K., Bandyopadhyay A., Shara M., Dalessandro E.,
Pandey G., Postma J.E., Hutchings J., Simunovic M., Stetson P. B.,
Thirupathi S., Puzia T., Sohn Y.-J.
<Mon. Not. R. Astron. Soc. 514, 1122 (2022)>
=2022MNRAS.514.1122S 2022MNRAS.514.1122S (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Populations, stellar ; Stars, white dwarf ;
Photometry ; Ultraviolet
Keywords: techniques: photometric - catalogues - blue stragglers -
Hertzsprung-Russell and colour-magnitude diagrams -
stars: horizontal branch - white dwarfs - globular clusters: general -
ultraviolet: general
Abstract:
We present the first results of eight globular clusters (GCs) from the
AstroSat/UVIT Legacy Survey programme GlobULeS based on the
observations carried out in two far-ultraviolet (FUV) filters (F148W
and F169M). The FUV-optical and FUV-FUV colour-magnitude
diagrams (CMDs) of GCs with the proper motion membership were
constructed by combining the Ultra-Violet Imaging Telescope (UVIT)
data with Hubble Space Telescope (HST) UV Globular Cluster Survey data
for inner regions and Gaia Early Data Release for regions outside the
HST's field. We detect sources as faint as F148W∼23.5mag, which
are classified based on their locations in CMDs by overlaying stellar
evolutionary models. The CMDs of eight GCs are combined with the
previous UVIT studies of three GCs to create stacked FUV-optical
CMDs to highlight the features/peculiarities found in the different
evolutionary sequences. The FUV (F148W) detected stellar populations
of 11 GCs comprise 2816 horizontal branch (HB) stars [190 extreme HB
(EHB) candidates], 46 post-HB (pHB), 221 blue straggler stars (BSSs),
and 107 white dwarf (WD) candidates. We note that the blue HB colour
extension obtained from F148W-G colour and the number of FUV
detected EHB candidates are strongly correlated with the maximum
internal helium (He) variation within each GC, suggesting that the
FUV-optical plane is the most sensitive to He abundance variations
in the HB. We discuss the potential science cases that will be
addressed using these catalogues including HB morphologies, BSSs, pHB,
and WD stars.
Description:
The GlobULeS catalogue (table4.dat) contains the photometric
measurements of hot stellar populations identified in eleven globular
clusters observed with the AstroSat/UVIT Far-Ultraviolet (FUV) channel
in the F148W and F169M filters.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 136 3183 UVIT photometric catalogue of Globular Clusters
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See also:
V/150 : Updated catalog of variable stars in globular clusters (Clement+ 2017)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Cluster Cluster Name
9- 18 A10 --- UVIT UVIT ID
20- 29 F10.6 deg RAdeg Right ascension (J2000)
31- 40 F10.6 deg DEdeg Declination (J2000)
42- 47 F6.3 mag F148W ?=- F148W magnitude [AB]
49- 53 F5.3 mag e_F148W ?=- rms uncertainty on F148W
55- 60 F6.3 mag F169M ?=- F169M magnitude [AB]
62- 66 F5.3 mag e_F169M ?=- rms uncertainty on F169M
68- 73 F6.3 mag Gmag ?=- G magnitude [AB] (1)
75- 79 F5.1 --- MemProb ?=-1 Membership probability (2)
81- 99 A19 --- uniqueID Unique ID (3)
101-104 A4 --- CMData Cross matched data
106-109 A4 --- Class Classification
111-113 A3 --- HBtype HB type
115-119 I5 K Teff ?=- Effective temperature (4)
121-136 A16 --- VarType Variable type (5)
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Note (1): The G magnitude is given in the AB system. For UVIT-Gaia sources,
it is taken from Gaia EDR3 (Gaia Collaboration et al., 2021A&A...649A...1G 2021A&A...649A...1G,
Cat. I/350), whereas for UVIT-HST sources it is derived by transforming HST
photometry to the Gaia G band (see Eq. 8 of the associated paper).
Note (2): The MemProb are adopted from the HUGS survey (Nardiello et al.,
18MNRAS.481.3382N) for UVIT-HST sources, while for UVIT-Gaia sources it
is derived in this work (see Sect. 3.2 of the associated paper).
Note (3): The uniqueID corresponds to the ID_number column of the HUGS
catalogue (Nardiello et al.. 2018MNRAS.481.3382N 2018MNRAS.481.3382N) for UVIT-HST sources
(except NGC 1904, for which the IDs are taken from Lanzoni et al.
(2007ApJ...663.1040L 2007ApJ...663.1040L), and to the source_id from Gaia EDR3 for UVIT-Gaia
sources.
Note (4): The effective temperatures of horizontal branch stars (Teff) are
estimated from the (F148W-G) versus Teff relation derived from stellar
evolutionary models.
Note (5): The Variable_type is adopted from the catalogue of Clement et al.
(2001AJ....122.2587C 2001AJ....122.2587C, Cat. V/150, updated online catalogue).
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Acknowledgements:
Snehalata Sahu, snehalatash30(at)gmail.com
License: CC-BY-4.0
(End) Patricia Vannier [CDS] 15-Jul-2026