J/A+A/677/A86 SHOTGLAS II. BHB stars in omega Cen and NGC 6752 (Latour+, 2023)
SHOTGLAS. II. MUSE spectroscopy of blue horizontal branch stars in the core
of ω Centauri and NGC 6752.
Latour M., Haemmerich S., Dorsch M., Heber U., Husser T.-O., Kamann S.,
Dreizler S., Brinchmann J.
<Astron. Astrophys. 677, A86 (2023)>
=2023A&A...677A..86L 2023A&A...677A..86L (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Stars, horizontal branch ; Spectroscopy ;
Photometry, ultraviolet ; Optical
Keywords: stars: fundamental parameters - stars: horizontal-branch -
globular clusters: individual: NGC 5139 -
globular clusters: individual: NGC 6752 -
Abstract:
In this work, we characterize the properties of HB stars in the GCs
ω Cen and NGC 6752. We use dedicated model atmospheres and
synthetic spectra grids computed using a hybrid LTE/NLTE modeling
approach to fit the MUSE spectra of HB stars hotter than 8000K in
both clusters. The spectral fits provide estimates of the effective
temperature (Teff), surface gravity (logg), and helium abundance of
the stars. The model grids are further used to fit the HST magnitudes,
meaning the spectral energy distributions (SED), of the stars. From
the SED fits, we derive the average reddening, radius, luminosity, and
mass of the stars in our sample. The atmospheric and stellar
properties that we derive for the stars in our sample are in good
agreement with the theoretical expectations. We use three different
diagnostics, namely the position of the G-jump and changes in
metallicity and helium abundances to place the onset of diffusion in
the stellar atmospheres at Teff between 11 and 11.5kK. Our sample
includes two stars known as photometric variables, we confirm one to
be a bona fide extreme HB object but the other is a blue straggler
star. Finally, unlike what has been reported in the literature, we do
not find significant differences between the properties of the stars
in both clusters.
Description:
We provide tabulated results from our spectral and photometric
analysis.
For each cluster we provide a table containing the results from the
spectral fit of the MUSE spectra, i.e., Teff, logg and the surface
helium abundance of the stars. For each cluster we provide two set of
results from the SED fits : with Teff fixed to the value obtained from
the spectral fit and with Teff left as a free parameter during the SED
fitting procedure. Additional information on the online tables can be
found in Appendix B of the article.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tableb1.dat 124 135 Atmospheric parameters for stars in NGC 6752
tableb2.dat 125 302 Atmospheric parameters for stars in ω Cen
tableb3.dat 296 135 SED fit results (Teff free) for NGC 6752
tableb4.dat 432 245 SED fit results (Teff free) for ω Cen
tableb5.dat 269 130 SED fit results (Teff fixed) for NGC 6752
tableb6.dat 410 232 SED fit results (Teff fixed) for ω Cen
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See also:
J/ApJ/710/1032 : Proper motions in ω Cen (Anderson+, 2010)
J/ApJ/842/6 : Astro-photometric catalog of NGC 5139 core (Bellini+, 2017)
J/A+A/618/A15 : Parameters of EHB stars in ω Cen (Latour+, 2018)
Byte-by-byte Description of file: tableb1.dat tableb2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
6- 12 I7 --- ID Star identification number
15- 24 F10.6 deg RAdeg Right ascension (J2000)
26- 35 F10.6 deg DEdeg Declination (J2000)
38- 42 I5 K Teff Effective temperature (Teff)
47- 51 I5 K b_Teff Minimum value of Teff (1)
56- 60 I5 K B_Teff Maximum value of Teff (1)
63- 66 F4.2 [cm/s2] logg Surface gravity in log (log g)
71- 74 F4.2 [cm/s2] b_logg Minimum value of log g (1)
79- 82 F4.2 [cm/s2] B_logg Maximum value of log g (1)
85- 89 F5.2 --- logN(He)/N(tot) Surface helium abundance ratio in log
92- 96 F5.2 --- b_logN(He)/N(tot) Minimum value of the He abundance
ratio (1)
99-103 F5.2 --- B_logN(He)/N(tot) Maximum value of the He abundance
ratio (1)
106-108 I3 --- SNR Signal-to-noise ratio of the spectrum
114-115 I2 --- NSpec Number or individual spectra combined
118-125 A8 --- Note Alternative star name and
identification of the blue
straggler stars (2)
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Note (1): Errors on the measurements are asymmetric and obtained by doing, e.g.
Teff minus b_Teff and B_Teff minus Teff.
Note (2): From Landsman et al., 1996ApJ...472L..93L 1996ApJ...472L..93L and
Kaluzny & Thompson, 2009AcA....59..273K 2009AcA....59..273K in tableb1 (NGC 6752).
From Whitney et al., 1994AJ....108.1350W 1994AJ....108.1350W, Cat. J/AJ/108/1350 and
Brown et al., 2017ApJ...851..118B 2017ApJ...851..118B in tableb2 (ω Cen).
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Byte-by-byte Description of file: tableb3.dat
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Bytes Format Units Label Explanations
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8- 12 I5 --- ID Star identification number
15- 24 F10.6 deg RAdeg Right ascension (J2000)
26- 35 F10.6 deg DEdeg Declination (J2000)
40- 44 I5 K SEDTeff Effective temperature from the SED fits
53- 57 I5 K b_SEDTeff Minimum value of Teff (1)
66- 70 I5 K B_SEDTeff Maximum value of Teff (1)
77- 83 F7.3 --- SEDlogtheta Solid angle θ (2*R/D) in log
94-100 F7.3 --- b_SEDlogtheta Minimum value of log θ (1)
111-117 F7.3 --- B_SEDlogtheta Maximum value of log θ (1)
120-123 F4.2 Rsun SEDR Radius
130-133 F4.2 Rsun b_SEDR Minimum value of the radius (1)
140-143 F4.2 Rsun B_SEDR Maximum value of the radius (1)
146-149 F4.2 Msun SEDM Mass
156-159 F4.2 Msun b_SEDM Minimum value of the mass (1)
166-169 F4.2 Msun B_SEDM Maximum value of the mass (1)
172-177 F6.2 Lsun SEDL Luminosity
182-187 F6.2 Lsun b_SEDL Minimum value of the luminosity (1)
192-197 F6.2 Lsun B_SEDL Maximum value of the luminosity (1)
200-205 F6.3 mag F275W ? Magnitude WFC3/UVIS F275W (2)
211-215 F5.3 mag e_F275W ? Error on the F275W magnitude (2)
218-223 F6.3 mag F336W ? Magnitude WFC3/UVIS F336W (2)
229-233 F5.3 mag e_F336W ? Error on the F336W magnitude (2)
236-241 F6.3 mag F435W Magnitude ACS/WFC F435W (2)
247-251 F5.3 mag e_F435W Error on the F435W magnitude (2)
254-259 F6.3 mag F606W Magnitude ACS/WFC F606W (2)
265-269 F5.3 mag e_F606W Error on the F606W magnitude (2)
272-277 F6.3 mag F814W Magnitude ACS/WFC F814W (2)
283-287 F5.3 mag e_F814W Error on the F814W magnitude (2)
290-296 A7 --- Note Alternative star name and identification of
the blue straggler stars (3)
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Note (1): Errors on the measurements are asymmetric and obtained by doing, e.g.
SEDTeff minus b_SEDTeff and B_SEDTeff minus SEDTeff.
Note (2): Magnitudes from Nardiello et al. (2018MNRAS.481.3382N 2018MNRAS.481.3382N)
https://archive.stsci.edu/prepds/hugs/
Note (3): From Landsman et al., 1996ApJ...472L..93L 1996ApJ...472L..93L and
Kaluzny & Thompson, 2009AcA....59..273K 2009AcA....59..273K.
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Byte-by-byte Description of file: tableb4.dat
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Bytes Format Units Label Explanations
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7- 12 I6 --- ID Star identification number
15- 24 F10.6 deg RAdeg Right ascension (J2000)
26- 35 F10.6 deg DEdeg Declination (J2000)
39- 44 I6 K SEDTeff Effective temperature from the SED fits
52- 57 I6 K b_SEDTeff Minimum value of Teff (1)
65- 70 I6 K B_SEDTeff Maximum value of Teff (1)
77- 83 F7.3 --- SEDlogtheta Solid angle θ (2*R/D) in log
94-100 F7.3 --- b_SEDlogtheta Minimum value of log θ (1)
111-117 F7.3 --- B_SEDlogtheta Maximum value of log θ (1)
120-123 F4.2 Rsun SEDR Radius
130-133 F4.2 Rsun b_SEDR Minimum value of the radius (1)
140-143 F4.2 Rsun B_SEDR Maximum value of the radius (1)
146-149 F4.2 Msun SEDM Mass
156-159 F4.2 Msun b_SEDM Minimum value of the mass (1)
166-169 F4.2 Msun B_SEDM Maximum value of the mass (1)
172-177 F6.2 Lsun SEDL Luminosity
182-187 F6.2 Lsun b_SEDL Minimum value of the luminosity (1)
192-197 F6.2 Lsun B_SEDL Maximum value of the luminosity (1)
200-205 F6.3 mag F225W ? Magnitude WFC3/UVIS F225W (2)
211-215 F5.3 mag e_F225W ? Error on the F225W magnitude (2)
218-224 F7.4 mag F275W ? Magnitude WFC3/UVIS F275W (2)
230-234 F5.3 mag e_F275W ? Error on the F275W magnitude (2)
237-242 F6.3 mag F336W ? Magnitude WFC3/UVIS F336W (2)
248-252 F5.3 mag e_F336W ? Error on the F336 magnitude (2)
255-260 F6.3 mag F390W ? Magnitude WFC3/UVIS F390W (2)
266-270 F5.3 mag e_F390W ? Error on the F390W magnitude (2)
273-278 F6.3 mag F438W ? Magnitude WFC3/UVIS F438W (2)
284-288 F5.3 mag e_F438W ? Error on the F438W magnitude (2)
291-296 F6.3 mag F555W Magnitude WFC3/UVIS F555W (2)
302-306 F5.3 mag e_F555W ? Error on the F555W magnitude (2)
309-314 F6.3 mag F606W Magnitude WFC3/UVIS F606W (2)
320-324 F5.3 mag e_F606W ? Error on the F606W magnitude (2)
327-332 F6.3 mag F775W ? Magnitude WFC3/UVIS F775W (2)
338-342 F5.3 mag e_F775W ? Error on the F775W magnitude (2)
345-350 F6.3 mag F814W Magnitude WFC3/UVIS F814W (2)
356-360 F5.3 mag e_F814W ? Error on the F814W magnitude (2)
366-371 F6.3 mag And10F435W ? Magnitude ACS/WFC F435W (3)
382-386 F5.3 mag e_And10F435W ? Error on the F435W magnitude (3)
392-397 F6.3 mag And10F625W ? Magnitude ACS/WFC F625W (3)
408-412 F5.3 mag e_And10F625W ? Error on the F625W magnitude (3)
417-422 I6 --- BelliniID ID from Bellini et al. 2017ApJ...842....6B 2017ApJ...842....6B,
Cat J/ApJ/842/6
425-432 A8 --- Note Alternative star name (4)
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Note (1): Errors on the measurements are asymmetric and obtained by doing, e.g.
SEDTeff minus b_SEDTeff and B_SEDTeff minus SEDTeff.
Note (2): Magnitudes from Bellini et al. 2017ApJ...842....6B 2017ApJ...842....6B, Cat J/ApJ/842/6.
Note (3): Magnitudes from Anderson et al., 2010ApJ...710.1032A 2010ApJ...710.1032A,
Cat J/ApJ/710/1032.
Note (4): From Whitney et al., 1994AJ....108.1350W 1994AJ....108.1350W, Cat. J/AJ/108/1350 and
Brown et al., 2017ApJ...851..118B 2017ApJ...851..118B.
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Byte-by-byte Description of file: tableb5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
3- 7 I5 --- ID Star identification number
10- 19 F10.6 deg RAdeg Right ascension (J2000)
21- 30 F10.6 deg DEdeg Declination (J2000)
39- 43 I5 K Teffspectro Effective temperature from the
spectroscopic fit
50- 56 F7.3 --- SEDlogtheta Solid angle θ (2*R/D) in log
67- 73 F7.3 --- b_SEDlogtheta Minimum value of log θ (1)
84- 90 F7.3 --- B_SEDlogtheta Maximum value of log θ (1)
93- 96 F4.2 Rsun SEDR Radius
103-106 F4.2 Rsun b_SEDR Minimum value of the radius (1)
113-116 F4.2 Rsun B_SEDR Maximum value of the radius (1)
119-122 F4.2 Msun SEDM Mass
129-132 F4.2 Msun b_SEDM Minimum value of the mass (1)
139-142 F4.2 Msun B_SEDM Maximum value of the mass (1)
145-150 F6.2 Lsun SEDL Luminosity
155-160 F6.2 Lsun b_SEDL Minimum value of the luminosity (1)
165-170 F6.2 Lsun B_SEDL Maximum value of the luminosity (1)
173-178 F6.3 mag F275W ? Magnitude WFC3/UVIS F275W (2)
184-188 F5.3 mag e_F275W ? Error on the F275W magnitude (2)
191-196 F6.3 mag F336W ? Magnitude WFC3/UVIS F336W (2)
202-206 F5.3 mag e_F336W ? Error on the F336W magnitude (2)
209-214 F6.3 mag F435W Magnitude ACS/WFC F435W (2)
220-224 F5.3 mag e_F435W Error on the F435W magnitude (2)
227-232 F6.3 mag F606W Magnitude ACS/WFC F606W (2)
238-242 F5.3 mag e_F606W Error on the F606W magnitude (2)
245-250 F6.3 mag F814W Magnitude ACS/WFC F814W (2)
256-260 F5.3 mag e_F814W Error on the F814W magnitude (2)
263-269 A7 --- Note Alternative star name and identification
of the blue straggler stars (3)
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Note (1): Errors on the measurements are asymmetric and obtained by doing, e.g.
SEDTeff minus b_SEDTeff and B_SEDTeff minus SEDTeff.
Note (2): Magnitudes from Nardiello et al. (2018MNRAS.481.3382N 2018MNRAS.481.3382N),
https://archive.stsci.edu/prepds/hugs/
Note (3): From Landsman et al., 1996ApJ...472L..93L 1996ApJ...472L..93L and
Kaluzny & Thompson, 2009AcA....59..273K 2009AcA....59..273K
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Byte-by-byte Description of file: tableb6.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
7- 12 I6 --- ID Star identification number
15- 24 F10.6 deg RAdeg Right ascension (J2000)
26- 35 F10.6 deg DEdeg Declination (J2000)
44- 48 I5 K Teffspectro Effective temperature from the
spectroscopic fit
55- 61 F7.3 --- SEDlogtheta Solid angle θ (2*R/D) in log
72- 78 F7.3 --- b_SEDlogtheta Minimum value of log θ (1)
89- 95 F7.3 --- B_SEDlogtheta Maximum value of log θ (1)
98-101 F4.2 Rsun SEDR Radius
108-111 F4.2 Rsun b_SEDR Minimum value of the radius (1)
118-121 F4.2 Rsun B_SEDR Maximum value of the radius (1)
124-127 F4.2 Msun SEDM Mass
134-137 F4.2 Msun b_SEDM Minimum value of the mass (1)
144-147 F4.2 Msun B_SEDM Maximum value of the mass (1)
150-155 F6.2 Lsun SEDL Luminosity
161-165 F5.2 Lsun b_SEDL Minimum value of the luminosity (1)
170-175 F6.2 Lsun B_SEDL Maximum value of the luminosity (1)
178-183 F6.3 mag F225W ? Magnitude WFC3/UVIS F225W (2)
189-193 F5.3 mag e_F225W ? Error on the F225W magnitude (2)
196-202 F7.4 mag F275W ? Magnitude WFC3/UVIS F275W (2)
208-212 F5.3 mag e_F275W ? Error on the F275W magnitude (2)
215-220 F6.3 mag F336W ? Magnitude WFC3/UVIS F336W (2)
226-230 F5.3 mag e_F336W ? Error on the F336 magnitude (2)
233-238 F6.3 mag F390W ? Magnitude WFC3/UVIS F390W (2)
244-248 F5.3 mag e_F390W ? Error on the F390W magnitude (2)
251-256 F6.3 mag F438W ? Magnitude WFC3/UVIS F438W (2)
262-266 F5.3 mag e_F438W ? Error on the F438W magnitude (2)
269-274 F6.3 mag F555W Magnitude WFC3/UVIS F555W (2)
280-284 F5.3 mag e_F555W ? Error on the F555W magnitude (2)
287-292 F6.3 mag F606W Magnitude WFC3/UVIS F606W (2)
298-302 F5.3 mag e_F606W ? Error on the F606W magnitude (2)
305-310 F6.3 mag F775W ? Magnitude WFC3/UVIS F775W (2)
316-320 F5.3 mag e_F775W ? Error on the F775W magnitude (2)
323-328 F6.3 mag F814W Magnitude WFC3/UVIS F814W (2)
334-338 F5.3 mag e_F814W ? Error on the F814W magnitude (2)
344-349 F6.3 mag And10F435W ? Magnitude ACS/WFC F435W (3)
360-364 F5.3 mag e_And10F435W ? Error on the F435W magnitude (3)
370-375 F6.3 mag And10F625W ? Magnitude ACS/WFC F625W (3)
386-390 F5.3 mag e_And10F625W ? Error on the F625W magnitude (3)
395-400 I6 --- BelliniID ID from Bellini+, 2017
403-410 A8 --- Note Alternative star name (4)
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Note (1): Errors on the measurements are asymmetric and obtained by doing, e.g.
SEDTeff minus b_SEDTeff and B_SEDTeff minus SEDTeff.
Note (2): Magnitudes from Bellini et al. 2017ApJ...842....6B 2017ApJ...842....6B, Cat J/ApJ/842/6.
Note (3): Magnitudes from Anderson et al., 2010ApJ...710.1032A 2010ApJ...710.1032A,
Cat J/ApJ/710/1032.
Note (4): From Whitney et al., 1994AJ....108.1350W 1994AJ....108.1350W, Cat. J/AJ/108/1350 and
Brown et al., 2017ApJ...851..118B 2017ApJ...851..118B.
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Acknowledgements:
Marilyn Latour, marilyn.latour(at)uni-goettingen.de
References:
Latour et al., Paper I 2018A&A...618A..15L 2018A&A...618A..15L, Cat. J/A+A/618/A15
(End) Patricia Vannier [CDS] 15-Jul-2023