arXiv subjects

Dae-Hee Lee

Publications and source records attributed to Dae-Hee Lee.

10 recordsLinked to original sources

arXiv2025

The Cosmic Infrared Background Experiment-2: An Intensity Mapping Optimized Sounding-rocket Payload to Understand the Near-IR Extragalactic Background Light

The background light produced by emission from all sources over cosmic history is a powerful diagnostic of structure formation and evolution. At near-infrared wavelengths, this extragalactic background light (EBL) is comprised of emission from galaxies stretching all the way back to the first-light objects present during the Epoch of Reionization. The Cosmic Infrared Background Experiment 2 (CIBER-2) is a sounding-rocket experiment designed to measure both the absolute photometric brightness of the EBL over 0.5 - 2.0 microns and perform an intensity mapping measurement of EBL spatial fluctuations in six broad bands over the same wavelength range. CIBER-2 comprises a 28.5 cm, 80K telescope that images several square degrees to three separate cameras. Each camera is equipped with an HAWAII-2RG detector covered by an assembly that combines two broadband filters and a linear-variable filter, which perform the intensity mapping and absolute photometric measurements, respectively. CIBER-2 has flown three times: an engineering flight in 2021; a terminated launch in 2023; and a successful science flight in 2024. In this paper, we review the science case for the experiment; describe the factors motivating the instrument design; review the optical, mechanical, and electronic implementation of the instrument; present preflight laboratory characterization measurements; and finally assess the instrument's performance in flight.

astro-ph.IM↗

arXiv2020

Space Missions for Astronomy and Astrophysics in Korea: Past, Present, and Future

We review the history of space mission in Korea focusing on the field of astronomy and astrophysics. For each mission, scientific motivation and achievement are reviewed together with some technical details of the program including mission schedule. This review includes the ongoing and currently approved missions as well as some planned ones. Within the admitted limitations of authors' perspectives, some comments on the future direction of space program for astronomy and astrophysics in Korea are made at the end of this review.

astro-ph.IM↗

arXiv2018

MIRIS Paα Galactic Plane Survey. I. Comparison with IPHAS Hα in l = 96°-116°

The Multipurpose InfraRed Imaging System (MIRIS) performed the MIRIS Paα Galactic Plane Survey (MIPAPS), which covers the entire Galactic plane within the latitude range of -3° < b < +3° at Paα (1.87 um). We present the first result of the MIPAPS data extracted from the longitude range of l = 96.5°-116.3°, and demonstrate the data quality and scientific potential of the data by comparing them with Hα maps obtained from the INT Photometric Hα Survey (IPHAS) data. We newly identify 90 H II region candidates in the WISE H II region catalog as definite H II regions by detecting the Paα and/or Hα recombination lines, out of which 53 H II regions are detected at Paα. We also report the detection of additional 29 extended and 18 point-like sources at Paα. We estimate the E(B-V) color excesses and the total Lyman continuum luminosities for H II regions by combining the MIPAPS Paα and IPHAS Hα fluxes. The E(B-V) values are found to be systematically lower than those estimated from point stars associated with H II regions. Utilizing the MIPAPS Paα and IPHAS Hα images, we obtain an E(B-V) map for the entire region of the H II region Sh2-131 with an angular size of ~2.5°. The E(B-V) map shows not only numerous high-extinction filamentary features but also negative E(B-V) regions, indicating Hα excess. The Hα excess and the systematic underestimation of E(B-V) are attributed to light scattered by dust.

astro-ph.GA↗

arXiv2015

Cosmology with the SPHEREX All-Sky Spectral Survey

SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer) ( http://spherex.caltech.edu ) is a proposed all-sky spectroscopic survey satellite designed to address all three science goals in NASA's Astrophysics Division: probe the origin and destiny of our Universe; explore whether planets around other stars could harbor life; and explore the origin and evolution of galaxies. SPHEREx will scan a series of Linear Variable Filters systematically across the entire sky. The SPHEREx data set will contain R=40 spectra fir 0.75$<λ<$4.1$μ$m and R=150 spectra for 4.1$<λ<$4.8$μ$m for every 6.2 arc second pixel over the entire-sky. In this paper, we detail the extra-galactic and cosmological studies SPHEREx will enable and present detailed systematic effect evaluations. We also outline the Ice and Galaxy Evolution Investigations.

astro-ph.CO↗

arXiv2014

Global Far-Ultraviolet Properties of the Cygnus Loop

We present the C III λ977, O VI λλ1032, 1038 and N IV] λ1486 emission line maps of the Cygnus Loop, obtained with the newly processed data of Spectroscopy of Plasma Evolution from Astrophysical Radiation (SPEAR; also known as FIMS) mission. In addition, the Si IV+O IV] line complexes around 1400 Å are resolved into two separate emission lines, whose intensity demonstrates a relatively high Si IV region predicted in the previous study. The morphological similarity between the O VI and X-ray images, as well as a comparison of the O VI intensity with the value expected from the X-ray results, indicates that large portions of the observed O VI emissions could be produced from X-ray emitting gas. Comparisons of the far-ultraviolet (FUV) images with the optical and H I 21 cm images, reveal spatial variations of shock-velocity populations and high FUV extinction in the direction of a previously identified H I cloud. By calculating the FUV line ratios for several subregions of the Cygnus Loop, we investigate the spatial variation of the population of radiative shock velocities; and the effects of resonance scattering, X-ray emitting gas, and non-radiative shocks. The FUV and X-ray luminosity comparisons between the Cygnus Loop and the Vela supernova remnant suggest that the fraction of shocks in the early evolutionary stages is much larger in the Cygnus Loop.

astro-ph.GA↗

arXiv2011

Measuring Light from the Epoch of Reionization with CIBER, the Cosmic Infrared Background Experiment

Ultraviolet emission from the first generation of stars in the Universe ionized the intergalactic medium in a process which was completed by z~6; the wavelength of these photons has been redshifted by (1+z) into the near infrared today and can be measured using instruments situated above the Earth's atmosphere. First flying in February 2009, the Cosmic Infrared Background Experiment (CIBER) comprises four instruments housed in a single reusable sounding rocket borne payload. CIBER will measure spatial anisotropies in the extragalactic IR background caused by cosmological structure from the epoch of reionization using two broadband imaging instruments, make a detailed characterization of the spectral shape of the IR background using a low resolution spectrometer, and measure the absolute brightness of the Zodical light foreground with a high resolution spectrometer in each of our six science fields. This paper presents the scientific motivation for CIBER and details of its first two flights, including a review of the published scientific results from the first flight and an outlook for future reionization science with CIBER data.

astro-ph.CO↗

arXiv2009

Cosmic Infrared Background ExpeRiment (CIBER): A Probe of Extragalactic Background Light from Reionization

The Cosmic Infrared Background ExpeRiment (CIBER) is a rocket-borne absolute photometry imaging and spectroscopy experiment optimized to detect signatures of first-light galaxies present during reionization in the unresolved IR background. CIBER-I consists of a wide-field two-color camera for fluctuation measurements, a low-resolution absolute spectrometer for absolute EBL measurements, and a narrow-band imaging spectrometer to measure and correct scattered emission from the foreground zodiacal cloud. CIBER-I was successfully flown on February 25th, 2009 and has one more planned flight in early 2010. We propose, after several additional flights of CIBER-I, an improved CIBER-II camera consisting of a wide-field 30 cm imager operating in 4 bands between 0.5 and 2.1 microns. It is designed for a high significance detection of unresolved IR background fluctuations at the minimum level necessary for reionization. With a FOV 50 to 2000 times largerthan existing IR instruments on satellites, CIBER-II will carry out the definitive study to establish the surface density of sources responsible for reionization.

astro-ph.CO↗

arXiv2006

Diffuse Far-ultraviolet Observation of the Lupus Loop Region

Diffuse far-ultraviolet (FUV) emissions from the Lupus Loop region (SNR 330.0+15.0) have been observed with Spectroscopy of Plasma Evolution from Astrophysical Radiation (SPEAR), also known as Far-ultraviolet IMaging Spectrograph (FIMS). We have detected several important ionic lines, including Si II*, C IV, and N IV], which characterize the warm, hot ionized gas in this region. The spatial variations in the line intensities of Si II* and C IV have also been studied in comparison with X-ray and dust observations. The result shows that they originate from the interface between the hot gas seen in the X-ray and the cooler H I shell with which dust is associated. The interface is rather diffuse, and the gases with different temperatures seem to co-exist in this region. A shock may exist upfront in the interface, but its velocity should be very small as no shock-related distinguished feature is seen in Ha.

astro-ph↗

arXiv2006

Far-ultraviolet Observations of the North Ecliptic Pole with SPEAR

We present SPEAR/FIMS far-ultraviolet observations near the North Ecliptic Pole. This area, at b~30 degrees and with intermediate HI column, seems to be a fairly typical line of sight that is representative of general processes in the diffuse ISM. We detect a surprising number of emission lines of many elements at various ionization states representing gas phases from the warm neutral medium (WNM) to the hot ionized medium (HIM). We also detect fluorescence bands of H2, which may be due to the ubiquitous diffuse H2 previously observed in absorption.

astro-ph↗

arXiv2006

The SPEAR Instrument and On-Orbit Performance

The SPEAR (or 'FIMS') instrumentation has been used to conduct the first large-scale spectral mapping of diffuse cosmic far ultraviolet (FUV, 900-1750 AA) emission, including important diagnostics of interstellar hot (10^4 K - 10^6 K) and photoionized plasmas, H_2, and dust scattered starlight. The instrumentation's performance has allowed for the unprecedented detection of astrophysical diffuse far UV emission lines. A spectral resolution of 550 and an imaging resolution of 5' is achieved on-orbit in the Short (900 - 1175 AA) and Long (1335 - 1750 AA) bandpass channels within their respective 7.4 deg x 4.3' and 4.0 deg x 4.6' fields of view. We describe the SPEAR imaging spectrographs, their performance, and the nature and handling of their data.

astro-ph↗