Preprint
A Near-Infrared Extinction and Reddening Map Towards the Galactic Bulge Using UKIRT
ArXiv.org
Cornell University
09/29/2025
DOI: 10.48550/arxiv.2509.25440
Abstract
The Galactic bulge is one of the most information-dense regions to study resolved stellar populations, variables, and transients, such as microlensing events. Studies toward the Galactic bulge are complicated by the large and variable extinction along the line of sight. We measure the near-infrared A_{K_S} extinction and E(H-K_S) reddening in this region using H- and K-band photometry obtained with the 2017 UKIRT microlensing survey. We fit the apparent magnitude and color distribution of bright giants in the bulge to recover the apparent magnitude and color of Red Clump stars, which are known to be standard candles and crayons. We present 2^\prime \times 2^\prime resolution maps in UKIRT fields between -2.15^{\circ} \le l \le 2.71^{\circ} and -2.69^{\circ} \le b \le 2.03^{\circ} of the A_{K_S} extinction and the E(H-K_S) reddening. We find large variations in the K_S-band extinction and E(H-K_S) reddening on all the scales we probe. We find that a constant, standard extinction law is a poor representation of the relationship between the extinction and reddening we measure in fields of different latitudes. These maps will be useful for understanding the near-infrared extinction law for sight lines close to the Galactic plane, as well as for final field selection for the Nancy Grace Roman Space Telescope Galactic Bulge Time Domain Survey.
Details
- Title: Subtitle
- A Near-Infrared Extinction and Reddening Map Towards the Galactic Bulge Using UKIRT
- Creators
- Aiden S ZelakiewiczSamson A JohnsonB. Scott GaudiGeoffrey BrydenDavid M NatafYossi Shvartzvald
- Resource Type
- Preprint
- Publication Details
- ArXiv.org
- DOI
- 10.48550/arxiv.2509.25440
- ISSN
- 2331-8422
- Publisher
- Cornell University; Ithaca, New York
- Language
- English
- Date posted
- 09/29/2025
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984966697502771
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