J/ApJS/267/18 Abundance measurements in M15 RGB stars (Sandford+, 2023)
Validating stellar abundance measurements from multiresolution spectroscopy.
Sandford N.R., Weisz D.R., Ting Y.-S.
<Astrophys. J. Suppl. Ser., 267, 18 (2023)>
=2023ApJS..267...18S 2023ApJS..267...18S
ADC_Keywords: Abundances; Stars, giant; Spectroscopy; Optical;
Clusters, globular; Colors
Keywords: Fundamental parameters of stars ; Globular star clusters ;
Spectroscopy ; Stellar abundances ; Astronomy data analysis
Abstract:
Large-scale surveys will provide spectroscopy for ∼50 million resolved
stars in the Milky Way and Local Group. However, these data will have
a high degree of heterogeneity and most will be low-resolution
(R<10000), posing challenges to measuring consistent and reliable
stellar labels. Here, we introduce a framework for identifying and
remedying these issues. By simultaneously fitting the full spectrum
and Gaia photometry with the Payne, we measure ∼30 abundances for
eight metal-poor red giants in M15. From degraded quality Keck/HIRES
spectra, we evaluate trends with resolution and signal-to-noise ratio
(S/N) and find that (i) ∼20 abundances are recovered consistently
within ≲0.1dex agreement and with ≲0.05-0.15 dex systematic
uncertainties from 10000≲R≲80000; (ii) for nine elements (C, Mg, Ca,
Sc, Ti, Fe, Ni, Y, and Nd), this systematic precision and accuracy
extends down to R∼2500; and (iii) while most elements do not exhibit
strong S/N-dependent systematics, there are nonnegligible biases for
four elements (C, Mg, Ca, and Dy) below S/N∼10/pixel. We compare
statistical uncertainties from Markov Chain Monte Carlo sampling to
the easier-to-compute Cramer-Rao bounds and find that they agree for
∼85% of elements, indicating the latter to be a reliable and faster
way to estimate uncertainties. Our analysis illustrates the great
promise of low-resolution spectroscopy for stellar chemical abundance
work in the low-metallicity regime, and ongoing improvements to
stellar models (e.g., 3D-NLTE physics) will only further extend its
viability to more stars, more elements, and higher precision and
accuracy.
Description:
We use publicly available archival spectra from the Keck Observatory
Archive taken with the HIRES instrument on the Keck I Telescope. In
total, we analyze 40 individual spectra of eight RGB stars in the M15
globular cluster. Observations span the wavelength range 3160-8370Å
and provide nominal resolving powers (R=λ/δλ) from
37500-86600. In addition to archival Keck/HIRES spectroscopy, we also
employ Gaia DR3 photometry. Table 1 provides a list of the stars
analyzed in this work, and Table 2 provides a summary of the
spectroscopic observations. All of the stars considered in this study
reside on the upper portion of the red giant branch (RGB).
As a check on our fitting procedure, we compare our default
high-resolution high-S/N stellar label measurements to those measured
from previous stellar spectral analyses of the same stars. Our
high-resolution measurements and those included in the literature
comparison are presented in Table 9.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
21 29 58.32 +12 10 01.1 M15 = NGC 7078
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File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 53 8 M15 stars analyzed in this work
table2.dat 62 10 *HIRES observations of M15 stars
table9.dat 543 84 Literature stellar parameters (Appendix C)
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Note on table2.dat: Summary of archival observations analyzed in this work.
All raw data are available on the Keck Observatory Archive. Several
archival HIRES observations of M15 stars are omitted from this study
because they lack suitable flat-field exposures for PypeIt reductions
or lack Gaia photometry.
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
III/284 : APOGEE-2 data from DR16 (Johnsson+, 2020)
J/AJ/119/2274 : JK Photometry of globular clusters M15 & M56 (Ivanov+, 2000)
J/AJ/124/3255 : UBV photometry in M15 (van der Marel+, 2002)
J/A+A/416/1117 : Abundances in the early Galaxy (Cayrel+, 2004)
J/AJ/130/1177 : C and N abundances for M15 stars (Cohen+, 2005)
J/AJ/131/2949 : Mn abundances in cluster and field stars (Sobeck+, 2006)
J/AJ/135/1117 : Spectroscopic study of red giants in M15 (Meszaros+, 2008)
J/A+A/505/117 : Abundances of red giants in 15 GCls (Carretta+, 2009)
J/A+A/505/139 : Abundances of red giants in 17 GCls (Carretta+, 2009)
J/ApJ/705/328 : Abundance measurements in Sculptor dSph (Kirby+, 2009)
J/ApJS/191/352 : Abundances in stars of MW dwarf satellites (Kirby+, 2010)
J/ApJ/732/39 : Rotational velocities of K giant stars (Carlberg+, 2011)
J/AJ/141/175 : Abundances in M15 RGB/RHB stars (Sobeck+, 2011)
J/ApJ/771/67 : Abundances for 97 metal-poor stars. II. (Ishigaki+, 2013)
J/ApJ/795/23 : Line list for stellar chemical abundances (Bedell+, 2014)
J/A+A/561/A93 : On the metallicity of open clusters. II. (Heiter+, 2014)
J/AJ/149/153 : Abundances of red giants in 10 GCls (Meszaros+, 2015)
J/A+A/616/A10 : 46 open clusters GaiaDR2 HR diag. (Gaia Collaboration, 2018)
J/ApJS/237/18 : Cr, Co & Ni abund. for metal-poor red giants (Kirby+, 2018)
J/ApJ/857/2 : Abundances in 6 metal-poor stars (Roederer+, 2018)
J/ApJ/858/L7 : Red clump stars selected from LAMOST & APOGEE (Ting+, 2018)
J/ApJ/883/128 : Abundances in the giant stellar stream (Gilbert+, 2019)
J/A+A/628/A54 : Fe, Mg, Ti in Galactic clusters (Kovalev+, 2019)
J/A+A/622/A191 : 885 globular cluster giants abundances (Masseron+, 2019)
J/ApJS/245/34 : Abundances for 6 million stars from LAMOSTDR5 (Xiang+, 2019)
J/MNRAS/505/5978 : Gaia EDR3 view on Galactic GCls (Vasiliev+, 2021)
J/A+A/660/A88 : Abundances of Local Group globular clusters (Larsen+, 2022)
J/A+A/662/A66 : Hot stars from LAMOST DR6 (Xiang+, 2022)
http://koa.ipac.caltech.edu/ : Keck Observatory Archive home page
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- --- [K]
2- 4 I3 --- ID [341/969] Kustner identifier
(1921VeBon..15....1K 1921VeBon..15....1K ;
in Simbad)
6- 22 A17 --- 2MASS 2MASS name (JHHMMSSss+DDMMSSs)
24- 42 A19 --- OName Other name (s) (1)
44- 48 F5.2 mag Gmag0 [12.32/14.17] Gaia DR3 G-band magnitude;
corrected for extinction
50- 53 F4.2 mag Gbp-Grb0 [1.26/1.62] Gaia DR3 BP-RP color index
--------------------------------------------------------------------------------
Note (1): Alternative identifiers are: ARP = Arp (1955AJ.....60..317A 1955AJ.....60..317A),
CBG = Carretta+ (2009, J/A+A/505/139), and S = Sandage (1970ApJ...162..841S 1970ApJ...162..841S).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- --- [K]
2- 4 I3 --- ID [341/969] Kustner identifier
(1921VeBon..15....1K 1921VeBon..15....1K ;
in Simbad)
6- 9 I4 0.1nm lam1 [3650/3840] Lower range of wavelength in Å
10 A1 --- --- [-]
11- 14 I4 0.1nm lam2 [5200/8370] Upper range of wavelength in Å
16- 20 I5 --- Res [37500/86600] Resolution
(λ/δλ)
22- 31 A10 "D/M/Y" Date Date of observation (UT)
33- 38 A6 --- PID Observation program identifier
40- 47 A8 --- PI Program PI
49- 62 A14 s Exp Exposure(s) time
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table9.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 1 A1 --- --- [K]
2- 4 I3 --- ID [341/969] Kustner identifier
(1921VeBon..15....1K 1921VeBon..15....1K ;
in Simbad)
6- 22 A17 --- Ref Reference (1)
24- 30 F7.2 K Teff [4200/5154]? Effective temperature
32- 37 F6.2 K e_Teff [0.01/139]? Uncertainty in Teff
39- 39 A1 --- ll-Teff [TF] Lower limit flag in Teff
41- 41 A1 --- ul-Teff [TF] Upper limit flag in Teff
43- 46 F4.2 [cm/s2] logg [0.15/2.2]? log surface gravity
48- 51 F4.2 [cm/s2] e_logg [0/0.11]? Uncertainty in logg
53- 53 A1 --- ll-logg [TF] Lower limit flag in logg
55- 55 A1 --- ul-logg [TF] Upper limit flag in logg
57- 61 F5.2 [Sun] C [-0.71/1.4]? log C/Fe number abundance ratio
63- 66 F4.2 [Sun] e_C [0/0.2]? Uncertainty in C
68- 68 A1 --- ll-C [TF] Lower limit flag in C
70- 70 A1 --- ul-C [TF] Upper limit flag in C
72- 76 F5.2 [Sun] N [-0.06/1]? log N/Fe number abundance ratio
78- 81 F4.2 [Sun] e_N [0/0.12]? Uncertainty in N
83- 83 A1 --- ll-N [TF] Lower limit flag in N
85- 85 A1 --- ul-N [TF] Upper limit flag in N
87- 90 F4.2 [Sun] O [0.24/1.8]? log O/Fe number abundance ratio
92- 95 F4.2 [Sun] e_O [0/0.8]? Uncertainty in O
97- 97 A1 --- ll-O [TF] Lower limit flag in O
99- 99 A1 --- ul-O [TF] Upper limit flag in O
101-105 F5.2 [Sun] Na [-0.5/0.7]? log Na/Fe number abundance ratio
107-110 F4.2 [Sun] e_Na [0.01/0.2]? Uncertainty in Na
112-112 A1 --- ll-Na [TF] Lower limit flag in Na
114-114 A1 --- ul-Na [TF] Upper limit flag in Na
116-120 F5.2 [Sun] [Mg/Fe] [-0.21/0.7]? log of [Mg/Fe] abundance ratio
122-125 F4.2 [Sun] e_[Mg/Fe] [0.01/0.3]? Uncertainty in [Mg/Fe]
127-127 A1 --- ll-[Mg/Fe] [TF] Lower limit flag in Mg
129-129 A1 --- ul-[Mg/Fe] [TF] Upper limit flag in Mg
131-135 F5.2 [Sun] Al [-0.3/1.13]? log Al/Fe number abundance ratio
137-140 F4.2 [Sun] e_Al [0.01/0.9]? Uncertainty in Al
142-142 A1 --- ll-Al [TF] Lower limit flag in Al
144-144 A1 --- ul-Al [TF] Upper limit flag in Al
146-150 F5.2 [Sun] Si [-0.09/0.9]? log Si/Fe number abundance ratio
152-155 F4.2 [Sun] e_Si [0/0.2]? Uncertainty in Si
157-157 A1 --- ll-Si [TF] Lower limit flag in Si
159-159 A1 --- ul-Si [TF] Upper limit flag in Si
161-165 F5.2 [Sun] K [-0.22/1.6]? log K/Fe number abundance ratio
167-170 F4.2 [Sun] e_K [0.01/0.2]? Uncertainty in K
172-172 A1 --- ll-K [TF] Lower limit flag in K
174-174 A1 --- ul-K [TF] Upper limit flag in K
176-180 F5.2 [Sun] [Ca/Fe] [-0.01/0.7]? log of [Ca/Fe] abundance ratio
182-185 F4.2 [Sun] e_[Ca/Fe] [0/0.23]? Uncertainty in [Ca/Fe]
187-187 A1 --- ll-[Ca/Fe] [TF] Lower limit flag in [Ca/Fe]
189-189 A1 --- ul-[Ca/Fe] [TF] Upper limit flag in [Ca/Fe]
191-195 F5.2 [Sun] Sc [-0.4/0.2]? log Sc/Fe number abundance ratio
197-200 F4.2 [Sun] e_Sc [0/0.12]? Uncertainty in Sc
202-202 A1 --- ll-Sc [TF] Lower limit flag in Sc
204-204 A1 --- ul-Sc [TF] Upper limit flag in Sc
206-210 F5.2 [Sun] Ti [-0.1/0.67]? log Ti/Fe number abundance ratio
212-215 F4.2 [Sun] e_Ti [0/0.15]? Uncertainty in Ti
217-217 A1 --- ll-Ti [TF] Lower limit flag in Ti
219-219 A1 --- ul-Ti [TF] Upper limit flag in Ti
221-225 F5.2 [Sun] V [-0.1/0.91]? log V/Fe number abundance ratio
227-230 F4.2 [Sun] e_V [0/0.21]? Uncertainty in V
232-232 A1 --- ll-V [TF] Lower limit flag in V
234-234 A1 --- ul-V [TF] Upper limit flag in V
236-240 F5.2 [Sun] Cr [-0.4/0.15]? log Cr/Fe number abundance ratio
242-245 F4.2 [Sun] e_Cr [0/0.2]? Uncertainty in Cr
247-247 A1 --- ll-Cr [TF] Lower limit flag in Cr
249-249 A1 --- ul-Cr [TF] Upper limit flag in Cr
251-255 F5.2 [Sun] Mn [-0.63/0.7]? log Mn/Fe number abundance ratio
257-260 F4.2 [Sun] e_Mn [0.01/0.15]? Uncertainty in Mn
262-262 A1 --- ll-Mn [TF] Lower limit flag in Mn
264-264 A1 --- ul-Mn [TF] Upper limit flag in Mn
266-270 F5.2 [Sun] [Fe/H] [-2.7/-1.97]? log of [Fe/H] abundance ratio
272-275 F4.2 [Sun] e_[Fe/H] [0/0.23]? Uncertainty in [Fe/H]
277-277 A1 --- ll-[Fe/H] [TF] Lower limit flag in [Fe/H]
279-279 A1 --- ul-[Fe/H] [TF] Upper limit flag in [Fe/H]
281-284 F4.2 [Sun] Co [0.02/0.22]? log Co/Fe number abundance ratio
286-289 F4.2 [Sun] e_Co [0/0.21]? Uncertainty in Co
291-291 A1 --- ll-Co [TF] Lower limit flag in Co
293-293 A1 --- ul-Co [TF] Upper limit flag in Co
295-299 F5.2 [Sun] Ni [-0.22/0.6]? log Ni/Fe number abundance ratio
301-304 F4.2 [Sun] e_Ni [0/0.16]? Uncertainty in Ni
306-306 A1 --- ll-Ni [TF] Lower limit flag in Ni
308-308 A1 --- ul-Ni [TF] Upper limit flag in Ni
310-314 F5.2 [Sun] Cu [-0.5/0.44]? log Cu/Fe number abundance ratio
316-319 F4.2 [Sun] e_Cu [0.03/0.2]? Uncertainty in Cu
321-321 A1 --- ll-Cu [TF] Lower limit flag in Cu
323-323 A1 --- ul-Cu [TF] Upper limit flag in Cu
325-329 F5.2 [Sun] Zn [-0.3/0.21]? log Zn/Fe number abundance ratio
331-334 F4.2 [Sun] e_Zn [0.02/0.07]? Uncertainty in Zn
336-336 A1 --- ll-Zn [TF] Lower limit flag in Zn
338-338 A1 --- ul-Zn [TF] Upper limit flag in Zn
340-344 F5.2 [Sun] Sr [-0.32/0.4]? log Sr/Fe number abundance ratio
346-349 F4.2 [Sun] e_Sr [0.01/0.11]? Uncertainty in Sr
351-351 A1 --- ll-Sr [TF] Lower limit flag in Sr
353-353 A1 --- ul-Sr [TF] Upper limit flag in Sr
355-359 F5.2 [Sun] Y [-0.5/-0.07]? log Y/Fe number abundance ratio
361-364 F4.2 [Sun] e_Y [0/0.04]? Uncertainty in Y
366-366 A1 --- ll-Y [TF] Lower limit flag in Y
368-368 A1 --- ul-Y [TF] Upper limit flag in Y
370-374 F5.2 [Sun] Zr [-0.02/0.4]? log Zr/Fe number abundance ratio
376-379 F4.2 [Sun] e_Zr [0.01/0.2]? Uncertainty in Zr
381-381 A1 --- ll-Zr [TF] Lower limit flag in Zr
383-383 A1 --- ul-Zr [TF] Upper limit flag in Zr
385-389 F5.2 [Sun] Ba [-0.43/0.8]? log Ba/Fe number abundance ratio
391-394 F4.2 [Sun] e_Ba [0.01/0.1]? Uncertainty in Ba
396-396 A1 --- ll-Ba [TF] Lower limit flag in Ba
398-398 A1 --- ul-Ba [TF] Upper limit flag in Ba
400-404 F5.2 [Sun] La [-0.2/0.68]? log La/Fe number abundance ratio
406-409 F4.2 [Sun] e_La [0/0.1]? Uncertainty in La
411-411 A1 --- ll-La [TF] Lower limit flag in La
413-413 A1 --- ul-La [TF] Upper limit flag in La
415-419 F5.2 [Sun] Ce [-0.2/2]? log Ce/Fe number abundance ratio
421-424 F4.2 [Sun] e_Ce [0/0.2]? Uncertainty in Ce
426-426 A1 --- ll-Ce [TF] Lower limit flag in Ce
428-428 A1 --- ul-Ce [TF] Upper limit flag in Ce
430-433 F4.2 [Sun] Pr [0.1/0.64]? log Pr/Fe number abundance ratio
435-438 F4.2 [Sun] e_Pr [0/0.12]? Uncertainty in Pr
440-440 A1 --- ll-Pr [TF] Lower limit flag in Pr
442-442 A1 --- ul-Pr [TF] Upper limit flag in Pr
444-448 F5.2 [Sun] Nd [-0.06/0.6]? log Nd/Fe number abundance ratio
450-453 F4.2 [Sun] e_Nd [0/0.14]? Uncertainty in Nd
455-455 A1 --- ll-Nd [TF] Lower limit flag in Nd
457-457 A1 --- ul-Nd [TF] Upper limit flag in Nd
459-462 F4.2 [Sun] Sm [0.58/1]? log Sm/Fe number abundance ratio
464-467 F4.2 [Sun] e_Sm [0/0.1]? Uncertainty in Sm
469-469 A1 --- ll-Sm [TF] Lower limit flag in Sm
471-471 A1 --- ul-Sm [TF] Upper limit flag in Sm
473-476 F4.2 [Sun] Eu [0.13/1.12]? log Eu/Fe number abundance ratio
478-481 F4.2 [Sun] e_Eu [0.02/0.3]? Uncertainty in Eu
483-483 A1 --- ll-Eu [TF] Lower limit flag in Eu
485-485 A1 --- ul-Eu [TF] Upper limit flag in Eu
487-490 F4.2 [Sun] Gd [0.24/0.76]? log Gd/Fe number abundance ratio
492-495 F4.2 [Sun] e_Gd [0.01/0.08]? Uncertainty in Gd
497-497 A1 --- ll-Gd [TF] Lower limit flag in Gd
499-499 A1 --- ul-Gd [TF] Upper limit flag in Gd
501-504 F4.2 [Sun] Dy [0.23/0.9]? log Dy/Fe number abundance ratio
506-509 F4.2 [Sun] e_Dy [0.01/0.15]? Uncertainty in Dy
511-511 A1 --- ll-Dy [TF] Lower limit flag in Dy
513-513 A1 --- ul-Dy [TF] Upper limit flag in Dy
515-519 F5.2 [Sun] Er [-0.2/0.85]? log Er/Fe number abundance ratio
521-524 F4.2 [Sun] e_Er [0.01/0.15]? Uncertainty in Er
526-526 A1 --- ll-Er [TF] Lower limit flag in Er
528-528 A1 --- ul-Er [TF] Upper limit flag in Er
530-534 F5.2 [Sun] Th [-0.24/1]? log Th/Fe number abundance ratio
536-539 F4.2 [Sun] e_Th [0.01/0.4]? Uncertainty in Th
541-541 A1 --- ll-Th [TF] Lower limit flag in Th
543-543 A1 --- ul-Th [TF] Upper limit flag in Th
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Note (1): Reference as follows:
Carretta+ (2009a) = 2009A&A...505..117C 2009A&A...505..117C (Cat. J/A+A/505/117)
Carretta+ (2009b) = 2009A&A...505..139C 2009A&A...505..139C (Cat. J/A+A/505/139)
Jonsson+ (2020) = 2020AJ....160..120J 2020AJ....160..120J (APOGEE; Cat. III/284)
Kirby+ (2018) = 2018ApJS..237...18K 2018ApJS..237...18K (Cat. J/ApJS/237/18)
Letarte+ (2006) = 2006A&A...453..547L 2006A&A...453..547L
Masseron+ (2019) = 2019A&A...622A.191M 2019A&A...622A.191M (Cat. J/A+A/622/A191)
Otsuki+ (2006) = 2006ApJ...641L.117O 2006ApJ...641L.117O
Roederer+ (2009) = 2009ApJ...698.1963R 2009ApJ...698.1963R
Sneden+ (1997) = 1997AJ....114.1964S 1997AJ....114.1964S
Sneden+ (2000b) = 2006AJ....120.1351S 2006AJ....120.1351S
Sobeck+ (2006) = 2006AJ....131.2949S 2006AJ....131.2949S (Cat. J/AJ/131/2949)
Sobeck+ (2011) = 2011AJ....141..175S 2011AJ....141..175S (Cat. J/AJ/141/175)
Worley+ (2013) = 2013A&A...553A..47W 2013A&A...553A..47W
This Work = 2023ApJS..267...18S 2023ApJS..267...18S (This catalog)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 23-Aug-2023