Zobrazeno 1 - 10
of 201
pro vyhledávání: '"Chow-Choong Ngeow"'
Autor:
Vaidehi Varma, Chow-Choong Ngeow
Publikováno v:
The Astronomical Journal, Vol 168, Iss 1, p 43 (2024)
RRd stars are a subclass of RR Lyrae stars that pulsate simultaneously in the fundamental and the first-overtone radial modes. We report the analysis of 10 RRd stars discovered in the Sloan Digital Sky Survey (SDSS) Stripe 82 region of the Galactic h
Externí odkaz:
https://doaj.org/article/63842cf509b34969b2efcb6032ca0ebf
Autor:
Chow-Choong Ngeow, Anupam Bhardwaj
Publikováno v:
The Astronomical Journal, Vol 168, Iss 1, p 8 (2024)
Virgo III is a newly discovered ultra-faint-dwarf (UFD) candidate, and finding RR Lyrae associated with this galaxy is important to constrain its distance. In this work, we present a search of RR Lyrae in the vicinity of Virgo III based on the time-s
Externí odkaz:
https://doaj.org/article/8bd742f3065143818f0075281e478352
Autor:
Anupam Bhardwaj, Marina Rejkuba, Chow-Choong Ngeow, Marcella Marconi, Vincenzo Ripepi, Abhinna Sundar Samantaray, Harinder P. Singh
Publikováno v:
The Astronomical Journal, Vol 167, Iss 5, p 247 (2024)
The Draco Dwarf spheroidal (dSph) galaxy is one of the nearest and the most dark-matter-dominated satellites of the Milky Way. We obtained multiepoch near-infrared (NIR, JHK _s ) observations of the central region of Draco dSph covering a sky area of
Externí odkaz:
https://doaj.org/article/165b604f8526446495905cf142581d98
Autor:
Chow-Choong Ngeow, Anupam Bhardwaj
Publikováno v:
The Astronomical Journal, Vol 167, Iss 1, p 42 (2024)
Multiband light curves of two RR Lyrae variables in Segue II and Ursa Major II ultrafaint dwarf galaxies were collected from near simultaneous observations using the Lulin One-meter Telescope in Vgri bands. Together with Gaia G -band light curves, we
Externí odkaz:
https://doaj.org/article/67b7bbb2964a4f8abb8f84b495bd2395
Autor:
Anupam Bhardwaj, Adam G. Riess, Giovanni Catanzaro, Erasmo Trentin, Vincenzo Ripepi, Marina Rejkuba, Marcella Marconi, Chow-Choong Ngeow, Lucas M. Macri, Martino Romaniello, Roberto Molinaro, Harinder P. Singh, Shashi M. Kanbur
Publikováno v:
The Astrophysical Journal Letters, Vol 955, Iss 1, p L13 (2023)
Milky Way Cepheid variables with accurate Hubble Space Telescope photometry have been established as standards for primary calibration of the cosmic distance ladder to achieve a percent-level determination of the Hubble constant ( H _0 ). These 75 Ce
Externí odkaz:
https://doaj.org/article/3da763d2bc2a440096be96fbcaa622e6
Autor:
Anupam Bhardwaj, Marcella Marconi, Marina Rejkuba, Richard de Grijs, Harinder P. Singh, Vittorio F. Braga, Shashi Kanbur, Chow-Choong Ngeow, Vincenzo Ripepi, Giuseppe Bono, Giulia De Somma, Massimo Dall’Ora
Publikováno v:
The Astrophysical Journal Letters, Vol 944, Iss 2, p L51 (2023)
RR Lyrae variables are excellent Population II distance indicators thanks to their well-defined period–luminosity relations (PLRs) at infrared wavelengths. We present results of near-infrared (NIR) monitoring of Galactic globular clusters to empiri
Externí odkaz:
https://doaj.org/article/cbf576958b9f440ca45e3fe75f9babcb
Publikováno v:
The Astronomical Journal, Vol 167, Iss 1, p 14 (2023)
RR Lyrae stars (RRLs) are pulsating stars, many of which also show a long-term variation called the Blazhko effect which is a modulation of amplitude and phase of the lightcurve. In this work, we searched for the incidence rate of the Blazhko effect
Externí odkaz:
https://doaj.org/article/21bf7ef239cf4805a69318bfc16ff3d1
Autor:
Jia-Yu Ou, Chow-Choong Ngeow, Anupam Bhardwaj, Matthew J. Graham, Russ R. Laher, Frank J. Masci, Reed Riddle
Publikováno v:
The Astronomical Journal, Vol 165, Iss 4, p 137 (2023)
We present a systematic analysis to determine and improve the pulsation periods of 1637 known long-period Mira variables in M33 using gri -band light curves spanning ∼18 yr from several surveys, including the M33 variability survey, Panoramic Surve
Externí odkaz:
https://doaj.org/article/c082d59ea27f4270afb326c3288912a5
Autor:
Jeremy Dietrich, Dániel Apai, Martin Schlecker, Kevin K. Hardegree-Ullman, Benjamin V. Rackham, Nicolas Kurtovic, Karan Molaverdikhani, Paul Gabor, Thomas Henning, Wen-Ping Chen, Luigi Mancini, Alex Bixel, Aidan Gibbs, Richard P. Boyle, Samantha Brown-Sevilla, Remo Burn, Timmy N. Delage, Lizxandra Flores-Rivera, Riccardo Franceschi, Gabriele Pichierri, Sofia Savvidou, Jonas Syed, Ivan Bruni, Wing-Huen Ip, Chow-Choong Ngeow, An-Li Tsai, Chia-Lung Lin, Wei-Jie Hou, Hsiang-Yao Hsiao, Chi-Sheng Lin, Hung-Chin Lin, Ritvik Basant, Project EDEN
Publikováno v:
The Astronomical Journal, Vol 165, Iss 4, p 149 (2023)
Earth-sized exoplanets that transit nearby, late-spectral-type red dwarfs will be prime targets for atmospheric characterization in the coming decade. Such systems, however, are difficult to find via widefield transit surveys like Kepler or TESS. Con
Externí odkaz:
https://doaj.org/article/c5c7e471da4b4e448ec598b3407d09f5
Autor:
Chow-Choong Ngeow, Anupam Bhardwaj, Matthew J. Graham, Brian F. Healy, Russ R. Laher, Reed Riddle, Avery Wold
Publikováno v:
The Astronomical Journal, Vol 165, Iss 5, p 190 (2023)
SX Phoenicis (SXP) variables are short-period pulsating stars that exhibit a period–luminosity (PL) relation. We derived the gri -band PL and extinction-free period–Wesenheit (PW) relations, as well as the period-color and reddening-free period-Q
Externí odkaz:
https://doaj.org/article/7f050fc320684f30bd659d1e0a48406f