J/ApJ/950/83 Milky Way field red giant branch stars from Gaia DR3 (Li+, 2023)
A Gaia Data Release 3 view on the Tip of the Red Giant Branch luminosity.
Li S., Casertano S., Riess A.G.
<Astrophys. J., 950, 83 (2023)>
=2023ApJ...950...83L 2023ApJ...950...83L
ADC_Keywords: Stars, giant; Milky Way; Photometry; Optical; Surveys;
Parallaxes, trigonometric
Keywords: Milky Way Galaxy ; Calibration ; Red giant tip ; Distance indicators ;
Hubble constant ; Parallax ; Maximum likelihood estimation ;
Absolute magnitude ; Field stars
Abstract:
The tip of the red giant branch (TRGB) is a standard candle that can
be used to help refine the determination of the Hubble constant. Gaia
Data Release 3 (DR3) provides synthetic photometry constructed from
low-resolution BP/RP spectra for Milky Way field stars that can be
used to directly calibrate the luminosity of the TRGB in the
Johnson-Cousins I band, where the TRGB is least sensitive to
metallicity. We calibrate the TRGB luminosity using a two-dimensional
maximum likelihood algorithm with field stars and Gaia synthetic
photometry and parallaxes. For a high-contrast and low-contrast break
(characterized by the values of the contrast parameter R or the
magnitude of the break β), we find MTRGBI=-4.02 and -3.92mag
respectively, or a midpoint of
-3.970-0.024+0.042(sys)±0.062(stat)mag. This measurement
improves upon the TRGB measurement from Li+ (2022, J/ApJ/939/96), as
the higher precision photometry based on Gaia DR3 allows us to
constrain two additional free parameters of the luminosity function.
We also investigate the possibility of using Gaia DR3 synthetic
photometry to calibrate the TRGB luminosity with ω Centauri, but
find evidence of blending within the inner region for cluster member
photometry that precludes accurate calibration with Gaia DR3
photometry. We instead provide an updated TRGB measurement of
mTRGBI=9.82±0.04mag in ω Centauri using ground-based
photometry from the most recent version of the database described in
Stetson+ (2019, J/MNRAS/485/3042), which gives
MTRGBI=-3.97±0.04(stat)±0.10(sys)mag when tied to the Gaia
EDR3 parallax distance from the consensus of
Vasiliev & Baumgardt (2021, J/MNRAS/505/5978),
Soltis+ (2021, J/ApJ/908/L5), and Maiz Apellaniz J. (2022A&A...657A.130M 2022A&A...657A.130M).
Description:
The synthetic photometry based on Gaia DR3 has been calibrated using a
variety of methods, as described in Gaia Coll.+ (2023A&A...674A..33G 2023A&A...674A..33G).
However, our sample covers a limited range of stellar properties, in
particular magnitude; therefore it is worthwhile to verify the
validity and uncertainty of this calibration specifically for stars
with similar properties and for the Johnson-Kron-Cousins (JKC) system.
We tie the Gaia DR3 JKC synthetic photometry for our sample to Landolt
standards by a direct comparison between Gaia and reference photometry
for a subset of Landolt standards in the range of magnitude applicable
to our analysis, and apply the offset to the Gaia photometry for our
sample. See Section 2.2.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 79 1613 Milky Way field giants used for the tip of the red
giant branch (TRGB) measurement
--------------------------------------------------------------------------------
See also:
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
J/ApJ/829/108 : Kinematic data of Galactic globular clusters (Eadie+, 2016)
J/ApJ/874/150 : The first 3yrs of DES-SN (DES-SN3YR) (Brout+, 2019)
J/MNRAS/485/3042 : UBVRI photometry in 48 globular clusters (Stetson+, 2019)
J/A+A/654/A20 : Plx zero-point offset from Gaia EDR3 (Groenewegen, 2021)
J/A+A/649/A3 : Gaia EDR3 photometric passbands (Riello+, 2021)
J/ApJ/908/L5 : Color-magnitude diagram for ω Centauri (Soltis+, 2021)
J/MNRAS/505/5978 : Gaia EDR3 view on Gal. globular clusters (Vasiliev+, 2021)
J/ApJ/939/96 : Milky Way field giants from Gaia & APASS I-band (Li+, 2022)
J/A+A/674/A33 : Gaia synthetic phot. cat. of white dwarfs (Gaia Coll., 2023)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 I19 --- Gaia Gaia DR3 identifier
21- 27 F7.3 deg RAdeg Right Ascension (ICRS) at Ep=2016.0
29- 35 F7.3 deg DEdeg Declination (ICRS) at Ep=2016.0
37- 42 F6.3 mag Imag [8/11.7] Gaia Synthetic Photometry Catalog (GSPC)
I band synthetic Vega magnitude
44- 48 F5.3 mag e_Imag [0.01/0.05] Uncertainty in Imag
50- 55 F6.3 mag Vmag [9.2/13.5] Synthetic GSPC V band Vega magnitude
57- 61 F5.3 mag e_Vmag [0.01/0.08] Uncertainty in Vmag
63- 67 F5.3 mas plx [0.05/0.7] Gaia EDR3 parallax
69- 73 F5.3 mas e_plx [0.009/0.04] Uncertainty in plx
75- 79 F5.3 --- sinb [0.58/1] Sin of the absolute Galactic latitude,
sin(|b|)
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 30-Jul-2025