The Near-Infrared Tip of the Red Giant Branch. II. An Absolute Calibration in the Large Magellanic Cloud

TL;DR

This paper provides a new empirical calibration of the near-infrared tip of the red giant branch (TRGB) in the Large Magellanic Cloud using extensive survey data, improving distance measurement accuracy.

Contribution

It introduces an absolute calibration of the near-infrared TRGB in the LMC based on a large dataset and a geometric distance, enhancing previous calibrations.

Findings

Calibrated JHK zero-points for the TRGB in the LMC.

Revealed the 3D structure and tilt of the LMC.

Validated calibration with 2MASS survey data.

Abstract

We present a new empirical \(JHK\) absolute calibration of the tip of the red giant branch (TRGB) in the Large Magellanic Cloud (LMC). We use published data from the extensive \emph{Near-Infrared Synoptic Survey} containing 3.5 million stars, of which 65,000 are red giants that fall within one magnitude of the TRGB. Adopting the TRGB slopes from a companion study of the isolated dwarf galaxy IC\,1613 as well as an LMC distance modulus of \(\mu_0 = \)~18.49~mag from (geometric) detached eclipsing binaries, we derive absolute \(JHK\) zero-points for the near-infrared TRGB. For comparison with measurements in the bar alone, we apply the calibrated \(JHK\) TRGB to a 500 deg\textsuperscript{2} area of the 2MASS survey. The TRGB reveals the 3-dimensional structure of the LMC with a tilt in the direction perpendicular to the major axis of the bar, in agreement with previous studies.