A Near-infrared Extinction and Reddening Map toward the Galactic Bulge Using UKIRT

Aiden S Zelakiewicz; Samson A Johnson; B. Scott Gaudi; Geoffrey Bryden; David M Nataf; Yossi Shvartzvald

doi:10.3847/1538-3881/ae0c0b

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A Near-infrared Extinction and Reddening Map toward the Galactic Bulge Using UKIRT

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A Near-infrared Extinction and Reddening Map toward the Galactic Bulge Using UKIRT

Aiden S Zelakiewicz, Samson A Johnson, B. Scott Gaudi, Geoffrey Bryden, David M Nataf and Yossi Shvartzvald

The Astronomical journal, Vol.170(6), 328

12/01/2025

DOI: 10.3847/1538-3881/ae0c0b

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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 AKS extinction and E(H − KS) 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′×2′ resolution maps in UKIRT fields between −2 .° 15 ≤ l ≤ 2 .° 71 and −2 .° 69 ≤ b ≤ 2 .° 03 of the AKS extinction and the E(H − KS) reddening. We find large variations in the KS-band extinction and E(H − KS) 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.

Crayons

Extinction

Galactic bulge

Microlenses

Space telescopes

Stellar magnitude

Stellar populations

Details

Title: Subtitle: A Near-infrared Extinction and Reddening Map toward the Galactic Bulge Using UKIRT
Creators: Aiden S Zelakiewicz
Samson A Johnson
B. Scott Gaudi
Geoffrey Bryden
David M Nataf
Yossi Shvartzvald
Resource Type: Journal article
Publication Details: The Astronomical journal, Vol.170(6), 328
DOI: 10.3847/1538-3881/ae0c0b
ISSN: 1538-3881
eISSN: 1538-3881
Publisher: IOP Publishing
Grant note: National Aeronautics and Space Administration (NASA): NNG16PJ32
We would like to thank the anonymous referee for suggestions that significantly improved the quality of the paper.
Language: English
Date published: 12/01/2025
Academic Unit: Physics and Astronomy
Record Identifier: 9985027360002771

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