author = "Alonso-Garcia, Javier and Smith, Leigh C. and Catelan, M{\'a}rcio 
                         and Minniti, Dante and Navarrete, Camila and Borissova, Jura and 
                         Carballo-Bello, Julio A. and Ramos, Rodrigo Contreras and 
                         Fern{\'a}ndez-Trincado, Jos{\'e} G. and Lopes, Carlos Eduardo 
                         Ferreira and Gran, Felipe and Garro, Elisa R. and Geisleir, Doug 
                         and Guo, Zhen and Hempel, Maren and Kerins, Eamonn and Lucas, 
                         Philip W. and Palma, Tali and Peņa Ram{\'{\i}}rez, Karla and 
                         Ram{\'{\i}}rez Alegr{\'{\i}}a, Sebasti{\'a}n and Saito, 
                         Roberto K.",
          affiliation = "{Universidad de Antofagasta} and {University of Cambridge} and 
                         {Millennium Institute of Astrophysics} and {Universidad 
                         Andr{\'e}s Bello} and {Millennium Institute of Astrophysics} and 
                         {Millennium Institute of Astrophysics} and {Universidad de 
                         Tarapac{\'a}} and {Millennium Institute of Astrophysics} and 
                         {Universidad de Atacama} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)} and {Millennium Institute of Astrophysics} and 
                         {Universidad Andr{\'e}s Bello} and {Universidad de 
                         Concepci{\'o}n} and {University of Hertfordshire} and 
                         {Universidad Andr{\'e}s Bello} and {University of Manchester} and 
                         {University of Hertfordshire} and {Universidad Nacional de 
                         C{\'o}rdoba} and {Universidad de Antofagasta} and {Universidad de 
                         Antofagasta} and {Universidade Federal de Santa Catarina (UFSC)}",
                title = "Variable stars in the VVV globular clusters: II. NGC 6441, NGC 
                         6569, NGC 6626 (M 28), NGC 6656 (M 22), 2MASS-GC 02, and Terzan 
              journal = "Astronomy \& Astrophysics",
                 year = "2021",
               volume = "651",
                pages = "A47",
                month = "July",
             keywords = "Globular clusters: general, Stars: variables: general, Stars: 
                         variables: RR Lyrae.",
             abstract = "Context. The Galactic globular clusters (GGCs) located in the 
                         inner regions of the Milky Way suffer from high extinction that 
                         makes their observation challenging. High densities of field stars 
                         in their surroundings complicate their study even more. The VISTA 
                         Variables in the Via Lactea (VVV) survey provides a way to explore 
                         these GGCs in the near-infrared where extinction effects are 
                         highly diminished. Aims. We conduct a search for variable stars in 
                         several inner GGCs, taking advantage of the unique multi-epoch, 
                         wide-field, near-infrared photometry provided by the VVV survey. 
                         We are especially interested in detecting classical pulsators that 
                         will help us constrain the physical parameters of these GGCs. In 
                         this paper, the second of a series, we focus on NGC 6656 (M 22), 
                         NGC 6626 (M 28), NGC 6569, and NGC 6441; these four massive GGCs 
                         have known variable sources, but quite different metallicities. We 
                         also revisit 2MASS-GC 02 and Terzan 10, the two GGCs studied in 
                         the first paper of this series. Methods. We present an improved 
                         method and a new parameter that efficiently identify variable 
                         candidates in the GGCs. We also use the proper motions of those 
                         detected variable candidates and their positions in the sky and in 
                         the color-magnitude diagrams to assign membership to the GGCs. 
                         Results. We identify and parametrize in the near-infrared numerous 
                         variable sources in the studied GGCs, cataloging tens of 
                         previously undetected variable stars. We recover many known 
                         classical pulsators in these clusters, including the vast majority 
                         of their fundamental mode RR Lyrae. We use these pulsators to 
                         obtain distances and extinctions toward these objects. 
                         Recalibrated period-luminosity-metallicity relations for the RR 
                         Lyrae bring the distances to these GGCs to a closer agreement with 
                         those reported by Gaia, except for NGC 6441, which is an uncommon 
                         Oosterhoff III GGC. Recovered proper motions for these GGCs also 
                         agree with those reported by Gaia, except for 2MASS-GC 02, the 
                         most reddened GGC in our sample, where the VVV near-infrared 
                         measurements provide a more accurate determination of its proper 
                  doi = "10.1051/0004-6361/202140546",
                  url = "",
                 issn = "0004-6361 and 1432-0746",
             language = "en",
           targetfile = "alonso_variable.pdf",
        urlaccessdate = "2022, Jan. 26"