Kmtnet: A Network of 1.6 M Wide-Field Optical Telescopes Installed at Three Southern Observatories

Abstract

The Korea Microlensing Telescope Network (KMTNet) is a wide-field photometric system installed by the Korea Astronomy and Space Science Institute (KASI). Here, we present the overall technical specifications of the KMTNet observation system, test observation results, data transfer and image processing procedure, and finally, the KMTNet science programs. The system consists of three 1.6 m wide-field optical telescopes equipped with mosaic CCD cameras of 18k by 18k pixels. Each telescope provides a 2.0 by 2.0 square degree field of view. We have finished installing all three telescopes and cameras sequentially at the Cerro-Tololo Inter-American Observatory (CTIO) in Chile, the South African Astronomical Observatory (SAAO) in South Africa, and the Siding Spring Observatory (SSO) in Australia. This network of telescopes, which is spread over three different continents at a similar latitude of about −30 degrees, enables 24-hour continuous monitoring of targets observable in the Southern Hemisphere. The test observations showed good image quality that meets the seeing requirement of less than 1.0 arcsec in I-band. All of the observation data are transferred to the KMTNet data center at KASI via the international network communication and are processed with the KMTNet data pipeline. The primary scientific goal of the KMTNet is to discover numerous extrasolar planets toward the Galactic bulge by using the gravitational microlensing technique, especially earth-mass planets in the habitable zone. During the non-bulge season, the system is used for wide-field photometric survey science on supernovae, asteroids, and external galaxies.

Kmtnet Supernova Program Variable Objects I. NGC 2784 Field

“…Additionally, only a handful of low surface brightness dwarf galaxies have been identified from this group (Karachentsev et al 2014), while the deep multi-color stacked images obtainable in KSP are ideally suited to finding more such objects. In fact, Park et al (2016) recently identified more than 30 new dwarf galaxies in this group from the KSP data. We obtained a total of 1379 images almost equally distributed among three different bands of BV I.…”

“…of optical transients. The exact coordinates of the fields are available in Park et al (2016). The NGC 2784 galaxy group was chosen because of its large sky coverage at the declination of ∼ -24.2…”

“…KSP is a high-cadence (i.e., several exposures during a 24-h cycle), multi-color (BV I) search program of rapidly-evolving transients at early phases, focusing on discovery and monitoring of infant (i.e., less than a few hours from the explosion) supernovae using ∼ 17% of the entire observing time of the Korea Microlensing Telescope Network (KMTNet; Kim et al 2016Kim et al ) in 2015Kim et al -2019. The high-cadence, multi-color data from KSP using the network of three telescopes of 1.6-m size and 2…”

Photometric Study of Npa Rotator (5247) Krylov

“…We conducted photometric observations of (5247) Krylov at the three sites of KMTNet (Kim et al 2016): the Cerro-Tololo Inter-American Observatory (CTIO) in Chile, the South African Astronomical Observatory (SAAO) in South Africa, and the Siding Spring Observatory (SSO) in Australia. KMTNet consists of 1.6-m wide-field optical telescopes and 18K × 18K mosaicked CCDs with four 9K × 9K e2v chips.…”

“…Preprocessing of raw observed images was completed using the KMTNet pre-processing software (Kim et al 2016), hence crosstalk, overscan, bias and flat fielding corrections and trimming were applied. The world coordinate system (WCS) solution of the observed images is calculated using the USNO B1.0 catalog and matched with SCAMP (Bertin 2005) with an average astrometric error of 1.5…”