A5021026321- Gamma-ray bursts and supernovae
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Cosmic Phenomena
- Pulsars and Gravitational Waves Research
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Radio Astronomy Observations and Technology
- Stellar, planetary, and galactic studies
- Neutrino Physics Research
- CCD and CMOS Imaging Sensors
- Adaptive optics and wavefront sensing
Seoul National University
2019-2024
Abstract One of the keys to success multimessenger astronomy is rapid identification electromagnetic wave counterpart, kilonova (KN), gravitational-wave (GW) event. Despite its importance, it hard find a KN associated with GW event, due poorly constrained localization map and numerous signals that could be confused as KN. Here, we present Gravitational-wave Electromagnetic Counterpart Korean Observatory (GECKO) project, GECKO observation GW190425, prospects in fourth observing run (O4)...
Faint $z\sim5$ quasars with $M_{1450}\sim-23$ mag are known to be the potentially important contributors ultraviolet ionizing background in post-reionization era. However, their number density has not been well determined, making it difficult assess role early ionization of intergalactic medium (IGM). In this work, we present updated results our quasar survey using Infrared Medium-deep Survey (IMS), a near-infrared imaging covering an area 85 deg$^{2}$. From spectroscopic observations Gemini...
Abstract We present bolometric luminosity ( L bol ) and black hole (BH) mass M BH estimators based on mid-infrared (MIR) continuum (hereafter, MIR that are measured from infrared (IR) photometric data. The -based relatively immune dust extinction effects, hence they can be used for dust-obscured quasars. To derive the estimators, we use unobscured quasars selected Sloan Digital Sky Survey (SDSS) quasar catalog, which have wide ranges of (10 44.62 –10 46.16 erg s −1 7.14 9.69 ⊙ ). find...
Abstract The faint quasars with M 1450 > −24 mag are known to hold the key determination of ultraviolet emissivity for cosmic reionization. But only a few have been identified so far because limitations on survey data. Here we present first results z ∼ 5 quasar Infrared Medium-deep Survey (IMS), which covers ∼100 deg 2 areas in J band depths AB 23 mag. To improve selection methods, medium-band follow-up imaging has carried out using SED camera QUasars Early uNiverse (SQUEAN) Otto Struve...
Abstract The intergalactic medium (IGM) at z ∼ 5 to 6 is largely ionized, and yet the main source for IGM ionization in early universe uncertain. Of possible contributors are faint quasars with <?CDATA $-26\lesssim {M}_{1450}\lesssim -23$?> , but their number density poorly constrained 5. In this paper, we present our survey of European Large-Area Infrared Space Observatory Survey-North 1 (ELAIS-N1) field over a area 6.51 deg 2 examine if such can be dominant ionization. We use deep...
We present the result of Infrared Medium-deep Survey (IMS) $z\sim6$ quasar survey, using combination IMS near-infrared images and Canada-France-Hawaii Telescope Legacy (CFHTLS) optical images. The traditional color-selection method results in 25 candidates over $86$ deg$^{2}$. introduce corrected Akaike Information Criterion (AICc) with high-redshift late-type star models to prioritize efficiently. Among color-selected candidates, seven plausible finally passed AICc selection which three are...
TXS 0506+056 is a blazar that has been recently identified as the counterpart of neutrino event IceCube-170922A. Understanding type important to constrain emission mechanism, but nature still uncertain. As an attempt understand 0506+056, we report medium-band observation results covering wavelength range 0.575 1.025 $\mu$m. The use filters allow us examine if there were any significant changes in its spectral shapes over course one month and give better constraint on peak frequency...
Understanding the faint end of quasar luminosity function at a high redshift is important since number density quasars critical element in constraining ultraviolet (UV) photon budgets for ionizing intergalactic medium (IGM) early universe. Here, we present LF reaching $M_{1450} \sim -22.0$ AB mag $z\sim5$, about one magnitude deeper than previous UV LFs. We select $z\sim5$ with deep learning technique from data taken by Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP), covering 15.5...
One of the keys to success multimessenger astronomy is rapid identification electromagnetic wave counterpart, kilonova (KN), gravitational-wave (GW) event. Despite its importance, it hard find a KN associated with GW event, due poorly constrained localization map and numerous signals that could be confused as KN. Here, we present Gravitational-wave Electromagnetic Counterpart Korean Observatory (GECKO) project, GECKO observation GW190425, prospects in fourth observing run (O4) detectors. We...
Intensive Monitoring Survey of Nearby Galaxies (IMSNG) is a high cadence observation program monitoring nearby galaxies with probabilities hosting supernovae (SNe). IMSNG aims to constrain the SN explosion mechanism by inferring sizes progenitor systems through detection shock-heated emission that lasts less than few days after explosion. To catch signal, utilizes network 0.5-m 1-m class telescopes around world and monitors images 60 at distances D < 50 Mpc as short hours. The target are...