J/MNRAS/530/3391 Pristine Inner Galaxy Survey PIGS VIII (Ardern-Arentsen+, 2024)
The Pristine Inner Galaxy Survey (PIGS). VIII: Characterising the orbital
properties of the ancient, very metal-poor inner Milky Way.
Ardern-Arentsen A., Monari G., Queiroz A.B.A., Starkenburg E., Martin N.F.,
Chiappini C., Aguado D.S., Belokurov V., Carlberg R., Monty S., Myeong G.,
Schultheis M., Sestito F., Venn K.A., Vitali S., Yuan Z., Zhang H.,
Buder S., Lewis G.F., Oliver W.H., Wan Z., Zucker D.B.
<Mon. Not. R. Astron. Soc. 530, 3391-3411 (2024)>
=2024MNRAS.530.3391A 2024MNRAS.530.3391A (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way; Stars, metal-deficient; Abundances, [Fe/H]; Optical;
Effective temperatures; Stars, distances; Space velocities
Keywords: galaxy: formation - galaxy: kinematics and dynamics -
galaxy: stellar content - stars: Population II -
techniques: spectroscopic
Abstract:
The oldest stars in the Milky Way (born in the first few billion
years) are expected to have a high density in the inner few kpc,
spatially overlapping with the Galactic bulge. We use spectroscopic
data from the Pristine Inner Galaxy Survey (PIGS) to study the
dynamical properties of ancient, metal-poor inner Galaxy stars. We
compute distances using StarHorse, and orbital properties in a barred
Galactic potential. With this paper, we release the spectroscopic
AAT/PIGS catalogue (13235 stars). We find that most PIGS stars have
orbits typical for a pressure-supported population. The fraction of
stars confined to the inner Galaxy decreases with decreasing
metallicity, but many very metal-poor stars (VMP, [Fe/H]←2.0) stay
confined (∼ 60% stay within 5 kpc). The azimuthal velocity vphi also
decreases between [Fe/H]=-1.0 and -2.0, but is constant for VMP
stars (at ∼40km/s). The carbon-enhanced metal- poor (CEMP) stars in
PIGS appear to have similar orbital properties compared to normal VMP
stars. Our results suggest a possible transition between two
spheroidal components - a more metal-rich, more concentrated, faster
rotating component, and a more metal-poor, more extended and
slower/non-rotating component. We propose that the former may be
connected to pre-disc in-situ stars (or those born in large building
blocks), whereas the latter may be dominated by contributions from
smaller galaxies. This is an exciting era where large metal-poor
samples, such as in this work (as well as upcoming surveys, e.g.,
4MOST), shed light on the earliest evolution of our Galaxy.
Description:
These files constitute the PIGS/AAT spectroscopic data release. Table
D2 and D3 are part of the appendix of the paper.
The auxiliary table contains 50 draws for each of the dynamical
parameters, from which the percentiles in Table D3 are derived.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tabled2.dat 721 13235 PIGS stellar parameters
tabled3.dat 1136 10379 PIGS distances and orbital properties
tableaux.dat 382 518950 All 50 draws of PIGS distances and
orbital properties
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Byte-by-byte Description of file: tabled2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 27 A27 --- Star Unique Pristine target name,
Pristine_HHMMSS.ss+DDMMSS.s (starname)
29- 47 A19 --- Field AAT field name (see Table D1),
FieldDDD.d+DD.d (fieldname)
49- 67 I19 --- GaiaDR3 Gaia DR3 source ID (source_id)
69- 83 F15.11 deg RAdeg Right ascension (ICRS) at Ep=2016.0
from Gaia DR3 (ra)
85- 99 F15.11 deg DEdeg Declination from (ICRS) at Ep=2016.0
Gaia DR3 (dec)
101-124 F24.20 deg GLON [] Galactic longitude (l)
126-145 F20.16 deg GLAT Galactic latitude (b)
147-165 F19.16 --- E(B-V) ? Reddening E(B-V) from Green et al.
(2019ApJ...887...93G 2019ApJ...887...93G) (ebv_green19)
167-187 F21.16 --- SNR4000-4100 Signal-to-noise ratio between
3993-4093 (SNR40004100)
189-209 F21.16 --- SNR5000-5100 Signal-to-noise ratio between
4993-5093 (SNR50005100)
211-231 F21.16 --- SNRCaT Signal-to-noise ratio in the calcium
triplet (red arm) (SNR_CaT)
233-254 F22.16 km/s RV FXCOR radial velocity (rv)
256-275 F20.16 km/s e_RV FXCOR radial velocity uncertainty
(including 2km/s floor) (rv_err)
277-294 F18.13 K TeffF FERRE effective temperature (teff_ferre)
296-314 F19.14 K e_TeffFtot FERRE effective temperature uncertainty
(including 107K floor) (eteffferretot)
316-333 F18.16 [cm/s2] loggF FERRE surface gravity (logg_ferre)
335-352 F18.16 [cm/s2] e_loggFtot FERRE surface gravity uncertainty
(including 0.24 floor) (eloggferretot)
354-372 F19.16 --- [Fe/H]F FERRE metallicity (feh_ferre)
374-392 F19.16 --- e_[Fe/H]Ftot FERRE metallicity uncertainty
(including 0.13 floor) (efehferretot)
394-412 F19.16 --- [C/Fe]F FERRE carbon over iron abundance
(cfe_ferre)
414-433 F20.16 --- e_[C/Fe]Ftot FERRE carbon over iron abundance
uncertainty (including 0.20 floor)
(ecfeferretot)
435-456 F22.19 --- mccor100 ? median Placco et al.
(2014ApJ...797...21P 2014ApJ...797...21P) evolutionary
carbon correction (mccor100)
458-479 F22.19 --- s_nccor100 ? standard deviation of Placco et al.
(2014ApJ...797...21P 2014ApJ...797...21P) evolutionary
carbon correction (sccor100)
481-499 F19.16 --- chi2F FERRE log chi square (chi2_ferre)
501-519 F19.13 K TeffU ? ULySS effective temperature
(teff_ulyss)
521-539 F19.14 K e_TeffUtot ? ULySS effective temperature uncertainty
(including 107 K floor)
(eteffulysstot)
541-559 F19.16 [cm/s2] loggU ? ULySS surface gravity (logg_ulyss)
561-579 F19.16 [cm/s2] e_loggUtot ? ULySS surface gravity uncertainty
(including 0.24 floor) (eloggulysstot)
581-599 F19.16 --- [Fe/H]U ? ULySS metallicity (feh_ulyss)
601-619 F19.16 --- e_[Fe/H]Utot ? ULySS metallicity uncertainty
(including 0.13 floor) (efehulysstot)
621-641 F21.16 --- srrU ? ULySS signal-to-residual ratio
(srr_ulyss)
643-663 F21.15 --- sigU ? ULySS broadening width (sig_ulyss)
665-683 F19.16 --- fbpC2aU ? ULySS fraction of rejected pixels in
the fit between 4600-4800Å
(fbadpixC2a_ulyss)
685-703 F19.16 --- fbpC2bU ? ULySS fraction of rejected pixels in
the fit between 5000-5200Å
(fbadpixC2b_ulyss)
705-709 A5 --- double [false/true ] if True, the CaT spectrum
is clearly double-lined (most likely
chance-alignment) (double)
711-715 A5 --- goodF [false/true ] if True, star passes all
Arentsen et al. (2020MNRAS.496.4964A 2020MNRAS.496.4964A)
quality flags (FERRE case) (good_ferre)
717-721 A5 --- goodU [false/true ] if True, star passes all
Arentsen et al. (2020MNRAS.496.4964A 2020MNRAS.496.4964A)
quality flags (ULySS case) (good_ulyss)
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Byte-by-byte Description of file: tabled3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 27 A27 --- Star Unique Pristine target name,
Pristine_HHMMSS.ss+DDMMSS.s (starname)
29- 49 F21.18 --- [Fe/H] FERRE metallicity (repeated from Table D2
for convenience) (feh)
51- 69 F19.16 kpc dist16 16th percentile StarHorse distance
(dist16)
71- 89 F19.16 kpc dist50 Median StarHorse distance (dist50)
91- 109 F19.16 kpc dist84 84th percentile StarHorse distance
(dist84)
111- 134 F24.20 kpc x16 16th percentile Galactic x position (x16)
136- 159 E24.17 kpc x50 Median Galactic x position (x50)
161- 184 F24.20 kpc x84 84th percentile Galactic x position (x84)
186- 209 E24.17 kpc y16 16th percentile percentile Galactic
y position (y16)
211- 234 E24.17 kpc y50 Median Galactic y position (y50)
236- 259 E24.17 kpc y84 84th percentile Galactic y position (y84)
261- 280 F20.17 kpc z16 16th percentile Galactic z position (z16)
282- 301 F20.17 kpc z50 Median Galactic z position (z50)
303- 322 F20.17 kpc z84 84th percentile Galactic z position (z84)
324- 346 F23.18 km/s vR16 16th percentile Galactocentric
radial velocity (vR16)
348- 372 F25.19 km/s vR50 Median Galactocentric radial velocity
(vR50)
374- 397 F24.18 km/s vR84 84th percentile Galactocentric
radial velocity (vR84)
399- 422 F24.18 km/s vphi16 16th percentile Galactocentric
azimuthal velocity (vphi16)
424- 447 F24.18 km/s vphi50 Median Galactocentric azimuthal
velocity (vphi50)
449- 472 F24.18 km/s vphi84 84th percentile Galactocentric
azimuthal velocity (vphi84)
474- 497 F24.18 km/s vz16 16th percentile Galactocentric
vertical velocity (vz16)
499- 521 F23.18 km/s vz50 Median Galactocentric vertical velocity
(vz50)
523- 546 F24.19 km/s vz84 84th percentile Galactocentric
vertical velocity (vz84)
548- 568 F21.16 kpc apo16 ? 16th percentile Galactic apocentre
(apo16)
570- 590 F21.16 kpc apo50 ? Median Galactic apocentre (apo50)
592- 613 F22.16 kpc apo75 ? 75th percentile Galactic apocentre
(apo75)
615- 637 F23.16 kpc apo84 ? 84th percentile Galactic apocentre
(apo84)
639- 660 F22.18 kpc peri16 ? 16th percentile Galactic pericentre
(peri16)
662- 682 F21.17 kpc peri50 ? Median Galactic pericentre (peri50)
684- 704 F21.17 kpc peri84 ? 84th percentile Galactic pericentre
(peri84)
706- 727 F22.17 kpc zmax16 ? 16th percentile Maximum vertical
distance to the Galactic plane (zmax16)
729- 750 F22.17 kpc zmax50 ? Median Maximum vertical distance
to the Galactic plane (zmax50)
752- 774 F23.17 kpc zmax84 ? 84th percentile Maximum vertical
distance to the Galactic plane (zmax84)
776- 796 F21.18 --- ecc16 ? 16th percentile Orbital eccentricity
(ecc16)
798- 818 F21.18 --- ecc50 ? Median Orbital eccentricity (ecc50)
820- 840 F21.18 --- ecc84 ? 84th percentile Orbital eccentricity
(ecc84)
842- 866 F25.18 kpc.km/s JR16 ? 16th percentile Radial action (JR16)
868- 891 F24.17 kpc.km/s JR50 ? Median Radial action (JR50)
893- 916 F24.17 kpc.km/s JR84 ? 84th percentile Radial action (JR84)
918- 940 F23.17 kpc.km/s Jz16 ? 16th percentile Vertical action (Jz16)
942- 963 F22.16 kpc.km/s Jz50 ? Median Vertical action (Jz50)
965- 986 F22.16 kpc.km/s Jz84 ? 84th percentile Vertical action (Jz84)
988-1011 F24.17 kpc.km/s Jphi16 16th percentile Angular momentum (Jphi16)
1013-1037 F25.18 kpc.km/s Jphi50 Median Angular momentum (Jphi50)
1039-1064 F26.19 kpc.km/s Jphi84 84th percentile Angular momentum (Jphi84)
1066-1087 F22.13 kpc.km2/s2 Energy16 16th percentile Energy (Energy16)
1089-1111 F23.14 kpc.km2/s2 Energy50 Median Energy (Energy50)
1113-1136 F24.15 kpc.km2/s2 Energy84 84th percentile Energy (Energy84)
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Byte-by-byte Description of file: tableaux.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 27 A27 --- Star Unique Pristine target name (starname),
Pristine_HHMMSS.ss+DDMMSS.s (ID_pigs)
29- 30 I2 --- Sample [0/49] Sample number for this star
(Sample_ID)
32- 55 E24.17 kpc x Galactic x position (x)
57- 80 E24.17 kpc y Galactic y position (y)
82-104 F23.19 kpc z Galactic z position (z)
106-131 F26.20 km/s vR Galactocentric radial velocity (vR)
133-157 F25.19 km/s vphi Galactocentric azimuthal velocity (vphi)
159-180 E22.16 km/s vz Galactocentric vertical velocity (vz)
182-207 F26.16 km/s apo ? Galactic apocentre (apo)
209-230 F22.18 kpc peri ? Galactic pericentre (peri)
232-258 F27.18 kpc zmax ? Maximum vertical distance to the
Galactic plane (zmax)
260-280 F21.18 --- ecc ? Orbital eccentricity (ecc)
282-303 E22.16 kpc.km/s JR ? Radial action (JR)
305-331 F27.19 kpc.km/s Jphi Angular momentum (Jphi)
333-355 F23.17 kpc.km/s Jz ? Vertical action (Jz)
357-382 F26.17 kpc.km2/s2 Energy Energy (Energy)
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Acknowledgements:
Anke Ardern-Arentsen, anke.arentsen(at)ast.cam.ac.uk
References:
Arentsen et al., Paper II 2020MNRAS.496.4964A 2020MNRAS.496.4964A
Arentsen et al., Paper I 2020MNRAS.491L..11A 2020MNRAS.491L..11A
Arentsen et al., Paper III 2021MNRAS.505.1239A 2021MNRAS.505.1239A
Vitali et al., Paper IV 2022MNRAS.517.6121V 2022MNRAS.517.6121V
Sestito et al., Paper V 2023MNRAS.518.4557S 2023MNRAS.518.4557S
Zhao et al., Paper VI 2023MNRAS.519..754Z 2023MNRAS.519..754Z
Mashonkina et al., Paper VII 2023MNRAS.523.2111M 2023MNRAS.523.2111M
(End) Patricia Vannier [CDS] 19-Apr-2024