High-quality Extragalactic Legacy-field Monitoring (HELM) with DECam: Project Overview and First Data Release
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 deg 2 . 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.
Authors
- Paul Martini (ORCID: https://orcid.org/0000-0002-4279-4182)
- Scott F. Anderson (ORCID: https://orcid.org/0000-0002-6404-9562)
- U Malik (ORCID: https://orcid.org/0000-0002-0036-1696)
- M. Adamów (ORCID: https://orcid.org/0000-0002-6904-359X)
- W. N. Brandt (ORCID: https://orcid.org/0000-0002-0167-2453)
- Patrick Hartigan (ORCID: https://orcid.org/0000-0002-5380-549X)
- C. J. Grier (ORCID: https://orcid.org/0000-0001-9920-6057)
- Cláudio Ricci (ORCID: https://orcid.org/0000-0001-5231-2645)
- Patrick B. Hall (ORCID: https://orcid.org/0000-0002-1763-5825)
- Nathan Golovich (ORCID: https://orcid.org/0000-0003-2632-572X)
- F. E. Bauer (ORCID: https://orcid.org/0000-0002-8686-8737)
- Roberto J. Assef (ORCID: https://orcid.org/0000-0002-9508-3667)
- Zachary Stone (ORCID: https://orcid.org/0000-0002-8501-3518)
- Yu-Ching Chen (ORCID: https://orcid.org/0000-0002-9932-1298)
- Yongquan Xue (ORCID: https://orcid.org/0000-0002-1935-8104)
- Qian Yang (ORCID: https://orcid.org/0000-0002-6893-3742)
- Brad E. Tucker (ORCID: https://orcid.org/0000-0002-4283-5159)
- M. Salvato (ORCID: https://orcid.org/0000-0001-7116-9303)
- Alice Eltvedt
- Anton M. Koekemoer (ORCID: https://orcid.org/0000-0002-6610-2048)
- Xin Liu (ORCID: https://orcid.org/0000-0003-0049-5210)
- Zhefu Yu (ORCID: https://orcid.org/0000-0003-0644-9282)
- David E. Trilling (ORCID: https://orcid.org/0000-0003-4580-3790)
- T. M. C. Abbott (ORCID: https://orcid.org/0000-0003-1587-3931)
- K. Horne (ORCID: https://orcid.org/0000-0003-1728-0304)
- Junyao Li (ORCID: https://orcid.org/0000-0002-1605-915X)
- T. Dwelly (ORCID: https://orcid.org/0000-0002-4459-9233)
- Gloria Fonseca Alvarez (ORCID: https://orcid.org/0000-0003-0042-6936)
- A. C. Mangian (ORCID: https://orcid.org/0000-0003-2385-6904)
- M. Krumpe
- Yue Shen (ORCID: https://orcid.org/0000-0003-1659-7035)
- R. A. Gruendl (ORCID: https://orcid.org/0000-0002-4588-6517)
- J. Fu (ORCID: https://orcid.org/0000-0002-3767-299X)
- R. Sharp (ORCID: https://orcid.org/0000-0003-4877-7866)
- Jorge Casares (ORCID: https://orcid.org/0000-0001-5031-0128)
- A. Merloni (ORCID: https://orcid.org/0000-0002-0761-0130)
- A. Drlica-Wagner (ORCID: https://orcid.org/0000-0001-8251-933X)
- M. L. Graham (ORCID: https://orcid.org/0000-0002-9154-3136)
- Colin J. Burke (ORCID: https://orcid.org/0000-0001-9947-6911)
- Jennifer I-Hsiu Li (ORCID: https://orcid.org/0000-0002-0311-2812)
- Catherine Zucker (ORCID: https://orcid.org/0000-0002-2250-730X)
- César Fuentes (ORCID: https://orcid.org/0000-0002-5211-0020)
- R. M. Bielby (ORCID: https://orcid.org/0000-0001-9070-9969)
- Christopher E. Lidman (ORCID: https://orcid.org/0000-0003-1731-0497)
- Gisella De Rosa (ORCID: https://orcid.org/0000-0003-3242-7052)
- D. N. Friedel (ORCID: https://orcid.org/0000-0002-3632-7668)
- Ming-Yang Zhuang (ORCID: https://orcid.org/0000-0001-5105-2837)
- Zachary Wideman (ORCID: https://orcid.org/0000-0001-8171-5507)
- Di Wen (ORCID: https://orcid.org/0000-0003-2812-8607)
Publication Details
- Journal
- The Astrophysical Journal Supplement Series
- Published
- 2024-10-01
- DOI
- https://doi.org/10.3847/1538-4365/ad7d01
- Citations
- 2
- Primary Topic
- Gamma-ray bursts and supernovae
- Type
- article
- Field-Weighted Citation Impact
- 0.66
Funders
- National Science Foundation
- U.S. Department of Energy
- University of Pennsylvania
- Ohio State University
- University of Chicago
- University of Portsmouth
- University College London
- University of Sussex
- Deutsche Forschungsgemeinschaft
- National Natural Science Foundation of China
- Chinese Academy of Sciences
- Financiadora de Estudos e Projetos
- Agencia Nacional de Investigación y Desarrollo
- University of Illinois at Urbana-Champaign
- Science and Technology Facilities Council
- Integrated Electronics Engineering Center, Binghamton University
- Argonne National Laboratory
- Fermilab
- Lawrence Berkeley National Laboratory
- SLAC National Accelerator Laboratory