High-quality Extragalactic Legacy-field Monitoring (HELM) with DECam: Project Overview and First Data Release

Zhuang 庄, Ming-Yang 明阳; Yang, Qian; Shen, Yue; Adamów, Monika; Friedel, Douglas N.; Gruendl, R. A.; Stone, Zachary; Li, Junyao; Liu, Xin; Martini, Paul; Abbott, Timothy M. C.; Anderson, Scott F.; Assef, Roberto J.; Bauer, Franz E.; Bielby, Richard; Brandt, W. N.; Burke, Colin J.; Casares, Jorge; Chen, Yu-Ching; De Rosa, Gisella; Drlica-Wagner, Alex; Dwelly, Tom; Eltvedt, Alice; Fonseca Alvarez, Gloria; Fu 傅, Jianyang 健洋; Fuentes, Cesar; Graham, Melissa L.; Grier, Catherine J.; Golovich, Nathan; Hall, Patrick B.; Hartigan, Patrick; Horne, Keith; Koekemoer, Anton M.; Krumpe, Mirko; Li, Jennifer I.; Lidman, Chris; Malik, Umang; Mangian, Amelia; Merloni, Andrea; Ricci, Claudio; Salvato, Mara; Sharp, Rob; Trilling, David E.; Tucker, Brad E.; Wen, Di; Wideman, Zachary; Xue, Yongquan; Yu, Zhefu; Zucker, Catherine

Abstract

High-quality Extragalactic Legacy-field Monitoring (HELM) is a long-term observing program that photometrically monitors several well-studied extragalactic legacy fields with the Dark Energy Camera (DECam) imager on the CTIO 4 m Blanco telescope. Since 2019 February, HELM has been monitoring regions within COSMOS, XMM-LSS, CDF-S, S-CVZ, ELAIS-S1, and SDSS Stripe 82 with few-day cadences in the (u)gri(z) bands, over a collective sky area of ∼38 deg2. The main science goal of HELM is to provide high-quality optical light curves for a large sample of active galactic nuclei (AGNs), and to build decades-long time baselines when combining past and future optical light curves in these legacy fields. These optical images and light curves will facilitate the measurements of AGN reverberation mapping lags, as well as studies of AGN variability and its dependencies on accretion properties. In addition, the time-resolved and coadded DECam photometry will enable a broad range of science applications from galaxy evolution to time-domain science. We describe the design and implementation of the program and present the first data release that includes source catalogs and the first ∼3.5 yr of light curves during 2019A–2022A.

Citation

Zhuang 庄, M.-Y. 明., Yang, Q., Shen, Y., Adamów, M., Friedel, D. N., Gruendl, R. A., Stone, Z., Li, J., Liu, X., Martini, P., Abbott, T. M. C., Anderson, S. F., Assef, R. J., Bauer, F. E., Bielby, R., Brandt, W. N., Burke, C. J., Casares, J., Chen, Y.-C., De Rosa, G., …Zucker, C. (2024). High-quality Extragalactic Legacy-field Monitoring (HELM) with DECam: Project Overview and First Data Release. Astrophysical Journal Supplement, 274(2), Article 42. https://doi.org/10.3847/1538-4365/ad7d01

• Journal Article Type: Article
• Acceptance Date: Sep 17, 2024
• Online Publication Date: Oct 11, 2024
• Publication Date: 2024-10
• Deposit Date: Jan 22, 2025
• Publicly Available Date: Jan 22, 2025
• Journal: The Astrophysical Journal Supplement Series
• Print ISSN: 0067-0049
• Electronic ISSN: 1538-4365
• Publisher: American Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 274
• Issue: 2
• Article Number: 42
• DOI: https://doi.org/10.3847/1538-4365/ad7d01
• Public URL: https://durham-repository.worktribe.com/output/3347227