The UKIRT M33 Monitoring Project - VII. A 15-year K-band photometric catalogue of long-period variable stars in the central kiloparsec of M33
Abstract
We present a homogenised K-band photometric catalogue for the central ≈12 arcmin2 (≈0.9 kpc2) of the Triangulum spiral galaxy M33, combining four independent PSF-based near-infrared datasets obtained with UKIRT between 2003 and 2018. These comprise the 2003-2007 UIST multi-epoch monitoring survey, the 2005 UFTI K-band mosaic (for which we present new PSF photometry), new WFCAM PSF reductions for the four central tiles, and a single K-band epoch from the 2018 UKIRT Hemisphere Survey (UHS DR3). Cross-matching all four catalogues and retaining stars detected in at least two of them yields 847 unique stars comprising 21,085 valid K-band measurements spanning a baseline of 15.11 yr. Photometric homogenisation onto the 2MASS/Vega system via 82 low-scatter calibration stars removes systematic inter-dataset offsets of up to 0.22 mag. Of the 847 monitored stars, 771 (91 per cent) are classified as variable (σrms > 0.10 mag), including 385 high-amplitude variables (AK ≥ 1.0 mag): prime Mira-type long-period variable candidates for period determination. Cross-matching with archival Spitzer IRAC photometry yields 156 matched stars, of which 120 satisfy ⟨ K⟩ − [3.6] > 0.5 mag, identifying dust-enshrouded AGB candidates inaccessible to all-sky optical surveys. This catalogue constitutes the most extensive near-infrared photometric baseline assembled for AGB stars in any spiral galaxy beyond the Milky Way, providing the photometric foundation for the period-luminosity analysis and star-formation-history reconstruction in the companion Paper VIII. The full catalogue is available at the Centre de Données astronomiques de Strasbourg (CDS).
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BibTeX
@misc{alizadeh2026ukirt,
title = {{The UKIRT M33 Monitoring Project - VII. A 15-year K-band photometric catalogue of long-period variable stars in the central kiloparsec of M33}},
author = {Mina Alizadeh and Atefeh Javadi and Yousefali Abedini and Fatemeh Nikzat and Hedieh Abdollahi and Jacco Th. van Loon},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.37591},
eprint = {2610.37591},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.37591},
}
RIS
TY - UNPB
TI - The UKIRT M33 Monitoring Project - VII. A 15-year K-band photometric catalogue of long-period variable stars in the central kiloparsec of M33
AU - Mina Alizadeh
AU - Atefeh Javadi
AU - Yousefali Abedini
AU - Fatemeh Nikzat
AU - Hedieh Abdollahi
AU - Jacco Th. van Loon
PY - 2026
DA - 2026/10/27
PB - arXiv
DO - 10.48550/arxiv.2610.37591
UR - https://arxiv.org/abs/2610.37591
AB - We present a homogenised K-band photometric catalogue for the central ≈12 arcmin^2 (≈0.9 kpc^2) of the Triangulum spiral galaxy M33, combining four independent PSF-based near-infrared datasets obtained with UKIRT between 2003 and 2018. These comprise the 2003-2007 UIST multi-epoch monitoring survey, the 2005 UFTI K-band mosaic (for which we present new PSF photometry), new WFCAM PSF reductions for the four central tiles, and a single K-band epoch from the 2018 UKIRT Hemisphere Survey (UHS DR3). Cross-matching all four catalogues and retaining stars detected in at least two of them yields 847 unique stars comprising 21,085 valid K-band measurements spanning a baseline of 15.11 yr. Photometric homogenisation onto the 2MASS/Vega system via 82 low-scatter calibration stars removes systematic inter-dataset offsets of up to 0.22 mag. Of the 847 monitored stars, 771 (91 per cent) are classified as variable (σ_rms > 0.10 mag), including 385 high-amplitude variables (A_K ≥ 1.0 mag): prime Mira-type long-period variable candidates for period determination. Cross-matching with archival Spitzer IRAC photometry yields 156 matched stars, of which 120 satisfy ⟨ K⟩ − [3.6] > 0.5 mag, identifying dust-enshrouded AGB candidates inaccessible to all-sky optical surveys. This catalogue constitutes the most extensive near-infrared photometric baseline assembled for AGB stars in any spiral galaxy beyond the Milky Way, providing the photometric foundation for the period-luminosity analysis and star-formation-history reconstruction in the companion Paper VIII. The full catalogue is available at the Centre de Données astronomiques de Strasbourg (CDS).
ER -