J/A+A/624/A25 HST WFC3 photometry of NGC 2419 (Larsen+, 2019)
Hubble Space Telescope photometry of multiple stellar populations in the
inner parts of NGC 2419.
Larsen S.S., Baumgardt H., Bastian N, Hernandez S., Brodie J.P.
<Astron. Astrophys. 624, A25 (2019)>
=2019A&A...624A..25L 2019A&A...624A..25L (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Photometry, HST ; Photometry, UBVRI ;
Abundances, [Fe/H]
Keywords: globular clusters: individual (NGC 2419) - stars: abundances -
Hertzsprung-Russell and C-M diagrams
Abstract:
We present new deep imaging of the central regions of the remote
globular cluster NGC 2419, obtained with the F343N and F336W filters
of the Wide Field Camera 3 on board the Hubble Space Telescope. The
new data are combined with archival imaging to constrain nitrogen and
helium abundance variations within the cluster. We find a clearly
bimodal distribution of the nitrogen-sensitive F336W-F343N colours
of red giants, from which we estimate that about 55% of the giants
belong to a population with about normal (field-like) nitrogen
abundances (P1), while the remaining 45% belong to a nitrogen-rich
population (P2). On average, the P2 stars are more He-rich than the P1
stars, with an estimated mean difference of ΔY~=0.05, but the P2
stars exhibit a significant spread in He content and some may reach
ΔY~=0.13. A smaller He spread may also be present for the P1
stars. Additionally, stars with spectroscopically determined low Mg
abundances ([Mg/Fe]<0) are generally associated with P2. We find the
P2 stars to be slightly more centrally concentrated in NGC 2419 with a
projected half-number radius of about 10% less than for the P1 stars,
but the difference is not highly significant (p~=0.05). Using
published radial velocities, we find evidence of rotation for the P1
stars, whereas the results are inconclusive for the P2 stars, which
are consistent with no rotation as well as the same average rotation
found for the P1 stars. Because of the long relaxation time scale of
NGC 2419, the radial trends and kinematic properties of the
populations are expected to be relatively unaffected by dynamical
evolution. Hence, they provide constraints on formation scenarios for
multiple populations, which must account not only for the presence of
He spreads within sub-populations identified via CNO variations, but
also for the relatively modest differences in the spatial
distributions and kinematics of the populations.
Description:
tablea1.dat contains HST WFC3 PSF-fitting astrometry and photometry
for stars in NGC 2419.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 173 79078 Photometry for NGC 2419
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See also:
J/AJ/136/2259 : HST photometry of stars in NGC 2419 (Sandquist+, 2008)
J/A+A/581/A72 : ubvy photometry of NGC2419 (Frank+, 2015)
J/MNRAS/431/1995 : Deep uVI photometry of NGC2419 (Beccari+, 2013)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- Seq [1/79078] Running ID
7- 14 F8.3 pix Xpos CCD X coordinate
16- 23 F8.3 pix Ypos CCD Y coordinate
25- 37 F13.9 deg RAdeg Right Ascension (J2000.0)
39- 50 F12.9 deg DEdeg Declination (J2000.0)
52- 57 F6.3 mag mF336W F336W STMAG magnitude
59- 64 F6.3 mag e_mF336W Error on F336W magnitude
66- 71 F6.3 mag s_mF336W R.M.S on F336W magnitude measurements
73- 78 F6.3 mag mF343N F343N STMAG magnitude
80- 85 F6.3 mag e_mF343N Error on F343N magnitude
87- 92 F6.3 mag s_mF343N R.M.S on F343N magnitude measurements
94- 99 F6.3 mag mF438W F438W STMAG magnitude
101-106 F6.3 mag e_mF438W Error on F438W magnitude
108-113 F6.3 mag mF555W F555W STMAG magnitude
115-120 F6.3 mag e_mF555W Error on F555W magnitude
122-127 F6.3 mag mF606W F606W STMAG magnitude
129-134 F6.3 mag e_mF606W Error on F606W magnitude
136-141 F6.3 mag mF814W F814W STMAG magnitude
143-148 F6.3 mag e_mF814W Error on F814W magnitude
150-155 F6.3 mag mF850LP F850LP STMAG magnitude
157-162 F6.3 mag e_mF850LP Error on F850LP magnitude
164 I1 --- CCD15078 [1/2] CCD for GO-15078 data
166 I1 --- CCD11903 [1/2] CCD for GO-11903 data
168-173 F6.3 --- chi438 ALLFRAME chi-square for F438W fit
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Acknowledgements:
Soeren Larsen, s.larsen(at)astro.ru.nl
(End) Soeren Larsen [Radboud University], Patricia Vannier [CDS] 06-Feb-2019