Carbon Stars as Standard Candles: An Empirical Test for the Reddening, Metallicity, and Age Sensitivity of the J-region Asymptotic Giant Branch (JAGB) Method
The J-region Asymptotic Giant Branch (JAGB) method is a standard candle based on the intrinsic luminosities of carbon stars in the near infrared. We directly constrain the impact of metallicity, age, and reddening on the JAGB method. We assess how the mode, skew, and spread of the JAGB star luminosity function change throughout diverse stellar environments in M31's NE disk from 13<d<18 kpc using data from the Panchromatic Hubble Andromeda Treasury (PHAT). As expected, the mode is found to be fainter in higher-reddening regions. To cross-check this result, we also measure a fiducial J-band ground-based JAGB distance using data from the UKIRT/WFCam in M31's outermost disk (18<d<40 kpc) where internal reddening is minimal. We find that this J-band distance modulus agrees well with the F110W distance moduli measured in the lowest reddening regions of the PHAT data, demonstrating the JAGB method is most accurate if measured in the low-reddening outer disks of galaxies. On the other hand, the mode of the JAGB star luminosity function appears empirically to show no dependence on age or metallicity within the range -0.18<[M/H]<-0.26 dex. In conclusion, the JAGB method proves to be a robust standard candle capable of calibrating the luminosities of type Ia supernovae and therefore providing a high-accuracy, high-precision measurement of the Hubble constant.
The recently-developed J-region Asymptotic Giant Branch (JAGB) method has extraordinary potential as an extragalactic standard candle, capable of calibrating the absolute magnitudes of locally-accessible Type Ia supernovae, thereby leading to an independent determination of the Hubble constant. Using Gaia Early Data Release 3 (EDR3) parallaxes, we calibrate the zeropoint of the JAGB method, based on the mean luminosity of a color-selected subset of carbon-rich AGB stars. We identify Galactic carbon stars from the literature and use their near-infrared photometry and Gaia EDR3 parallaxes to mea…
The J-region asymptotic giant branch (JAGB) method is a new standard candle that is based on the stable intrinsic J-band magnitude of color-selected carbon stars, and has a precision comparable to other primary distance indicators such as Cepheids and the TRGB. We further test the accuracy of the JAGB method in the Local Group Galaxy M33. M33's moderate inclination, low metallicity, and nearby proximity make it an ideal laboratory for tests of systematics in local distance indicators. Using high-precision optical BVI and near-infrared JHK photometry, we explore the application of three indepen…
We present a new calibration of the J-band absolute magnitude of the JAGB method based on thermally pulsing AGB stars that are members of Milky Way open clusters, having distances and reddenings, independently compiled and published by Marigo et al (2022). 17 of these photometrically-selected J-Branch AGB stars give M_J = -6.40 mag with a scatter of +/-0.40 mag, and a sigma on the mean of +/-0.10 mag. Combining the Milky Way field carbon star calibration of Lee et al. (2021) with this determination gives a weighted average of M_J(MW) = -6.19 +/- 0.04 mag (error on the mean). This value is stat…
CHASE Spectral Survey I: Measuring Contamination in the Color-selected J-region Asymptotic Giant Branch Distance Indicator
University of California, Berkeley（加州大学伯克利分校）；The University of Tokyo（东京大学）；National Astronomical Observatory of Japan（日本国立天文台）；Space Telescope Science Institute（太空望远镜科学研究所）；Johns Hopkins University（约翰斯·霍普金斯大学）；Georg-August-Universität Göttingen（哥廷根大学）；Center for Astrophysics — Harvard & Smithsonian（哈佛-史密森尼天体物理中心）
Relativistic corrections are estimated for classical Cepheids and the Tip of the Red Giant Branch (TRGB stars), to enable future unbiased 1% measurements of Hubble's constant, $H_0$. We considered four effects: $K-$corrections, time-dilation, the apparent change of host dust extinction due to non-comoving reference frames, and the change of observed color due to redshift. Extinction-dependent $K-$corrections were computed using stellar atmosphere models applicable to giant stars for $0.005 < z < 0.03$ in HST, JWST, and 2MASS filters. The optical-NIR Wesenheit function advantageously combines f…
Reconnaissance with JWST of the J-region Asymptotic Giant Branch in Distance Ladder Galaxies: From Irregular Luminosity Functions to Approximation of the Hubble Constant
"SNe Ia twins" in the Hubble flow, and the determination of H0
Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas（基础物理研究所，西班牙高等科学研究委员会）；Institut de Ciències del Cosmos (UB–IEEC)（宇宙科学研究所（巴塞罗那大学-IEEC））；Instituto de Astrofísica de Canarias（加那利群岛天体物理研究所）；Universidad de La Laguna（拉古纳大学）；INAF - Osservatorio Astronomico di Padova（意大利国家天体物理研究所-帕多瓦天文台）
研究通过分析Ia型超新星双胞胎在哈勃流中的距离确定H₀，发现部分样本存在色度误差影响H₀计算，最终得到H₀的平均值为72.38±1.54(stat)±1.33(sys) km s⁻¹ Mpc⁻¹。
Variables in S-PLUS: I. Multiband period-luminosity relations and reddening maps of the Magellanic Clouds using classical Cepheids
NSF NOIRLab（美国国家光学红外天文研究实验室）；Pontificia Universidad Católica de Chile（智利天主教 Pontificia 大学）；Universidad de Atacama（阿塔卡马大学）；Universidade de São Paulo（圣保罗大学）；Instituto Nacional de Pesquisas Espaciais（巴西国家空间研究所）；University of New South Wales（新南威尔士大学）；University of Chicago（芝加哥大学）；CONICET（阿根廷国家科学研究委员会）；UNLP（拉普拉塔国立大学）；Observatório Nacional（巴西国家天文台）
We have obtained single-phase near-infrared (NIR) magnitudes in the J- and K-bands for 77 RR Lyrae (RRL) stars in the Fornax Dwarf Spheroidal Galaxy. We have used different theoretical and empirical NIR period-luminosity-metallicity calibrations for RRL stars to derive their absolute magnitudes, and found a true, reddening-corrected distance modulus of 20.818 +/- 0.015 (statistical) +/- 0.116 (systematic) mag. This value is in excellent agreement with the results obtained within the Araucaria Project from the NIR photometry of red clump stars (20.858 +/- 0.013 mag), the tip of the red giant br…
We obtained single-phase near-infrared (NIR) magnitudes in the $J$- and $K$-band for a sample of 33 RR Lyrae stars in the Carina dSph galaxy. Applying different theoretical and empirical calibrations of the NIR period-luminosity-metallicity relation for RR Lyrae stars, we find consistent results and obtain a true, reddening-corrected distance modulus of 20.118 $\pm$ 0.017 (statistical) $\pm$ 0.11 (systematic) mag. This value is in excellent agreement with the results obtained in the context of the Araucaria Project from NIR photometry of Red Clump stars (20.165 $\pm$ 0.015) and Tip of Red Gian…
Improving reddening estimates for RR Lyrae stars in the Gaia bands: a machine learning approach to the PAC(Z) relation
INAF - Osservatorio di Astrofisica e Scienza dello Spazio di Bologna（意大利国家天体物理研究所博洛尼亚天文与空间科学观测站）；Dipartimento di Fisica e Astronomia, Università di Bologna（博洛尼亚大学物理与天文系）
Context. RR Lyrae stars are useful standard candles allowing one to derive accurate distances for old star clusters. Based on the recent catalogues from OGLE-IV and Gaia Early Data Release 3 (EDR3), the distances can be improved for a few bulge globular clusters. Aims. The aim of this work is to derive an accurate distance for the following six moderately metal-poor, relatively high-reddening bulge globular clusters: NGC 6266, NGC 6441, NGC 6626, NGC 6638, NGC 6642, and NGC 6717. Methods. We combined newly available OGLE-IV catalogues of variable stars containing mean I magnitudes, with Clemen…
