https://ir.lib.ncu.edu.tw/handle/987654321/48 Search the Channel s https://ir.lib.ncu.edu.tw/simple-search https://ir.lib.ncu.edu.tw/handle/987654321/109930 title: Injection to Near-Earth Asteroids from Maria asteroid family nearby 3:1 resonance;Injection to Near-Earth Asteroids from Maria asteroid family nearby 3:1 resonance abstract: 近地小行星主要源自主帶小行星，其演化過程是透過亞爾科夫斯基效應與平均運動共振的共同作用所驅動。熱漂移將小行星推入共振區域，隨後引力攝動會放大其軌道離心率，進而產生穿越火星軌道的路徑並注入近地小行星區域。本次研究探討瑪利亞星小行星家族成員的長期軌道演化，該星族為部位於強烈的 3:1 木星平均運動共振附近的主帶星族。我們透過對所選瑪利亞星族成員的克卜勒軌道要素進行數值積分，並追蹤其從主帶進入內太陽系軌道的動力學路徑。我們的模擬證實，與 3:1 平均運動共振的相互作用會大幅增加離心率（$e$），從而高效地驅動天體穿越火星軌道並進入近地小行星空間。至關重要的是，數值積分結果揭示了部分逃逸成員經歷了極端的軌道傾角（$i$）激發，超過 $90^\circ$ 並從順行運動轉變為逆行運動。我們分析了這些劇烈的傾角倒轉究竟是與高偏心率階段解耦，抑或是由高偏心率階段所驅動（例如在共振內部透過古薩-利多夫機制所致）。此外，我們也將這些由動力學產生的逆行天體與本質上即擁有逆行軌道的小行星進行了比較。這些結果表明，瑪利亞星族不僅是典型順行近地小行星的來源，同時也是不尋常的高傾角或逆行近地天體的源頭。透過繪製 3:1 平均運動共振附近偏心率激增與傾角驟升之間的耦合關係，也在本次研究為共振輸送機制以及內太陽系極端傾角天體的起源提供了關鍵見解。;Near-Earth Asteroids (NEAs) predominantly originate from Main-Belt Asteroids (MBAs) through the combined action of the Yarkovsky effect and mean-motion resonances (MMRs). Thermal drift pushes asteroids into resonant regions， where gravitational perturbations amplify eccentricities， leading to Mars-crossing trajectories and NEA injection. This study investigates the long-term orbital evolution of members of the Maria family， a main-belt family situated near the strong 3:1 Jupiter MMR. By numerically integrating the Keplerian elements of selected Maria members， we trace their dynamical pathways from the main belt into inner Solar System orbits. Our simulations confirm that interaction with the 3:1 MMR dramatically increases eccentricity ($e$)， efficiently driving objects across the Martian orbit and into NEA space. Crucially， the integrations reveal that a subset of escaping members undergoes extreme inclination ($i$) excitation， exceeding $90^\circ$ and transitioning from prograde to retrograde motion. We analyze whether these dramatic inclination inversions are decoupled from or driven by high-eccentricity phases， such as through Kozai-Lidov dynamics within the resonance. Furthermore， we compare these dynamically generated retrograde bodies with asteroids that possess intrinsically retrograde orbits. These results demonstrate that the Maria family serves as a source for both typical prograde NEAs and unusual， high-inclination or retrograde Near-Earth Objects. By mapping the coupling between eccentricity pump-up and inclination spikes near the 3:1 MMR， this work offers key insights into resonant transport mechanisms and the origin of extreme-inclination bodies in the inner Solar System. <br> https://ir.lib.ncu.edu.tw/handle/987654321/109926 title: Pictor I 矮星系中 RR Lyrae 變星之搜尋與驗證;Pictor I 矮星系中 RR Lyrae 變星之搜尋與驗證 abstract: Ultra-faint dwarf 為早期宇宙的遺跡，由於其整體光度極低，導致確認其真實距離與物理本質十分不易，RR Lyrae 作為經典的標準燭光，是提供獨立距離估計的關鍵物理探針，本研究利用 DECam 的多波段（g， r， i， z）時間序列成像數據，對 UFD 候選星系 Pictor I 進行了變星搜尋，與過 往類似的 UFD 變星搜尋研究相比，本研究所使用的資料集提供了更密 集的時間採樣，在 i 波段中最多包含高達 51 個曆元。 在候選天體的篩選流程中，本研究將 CMD 條件與 χ2 × MAD 變異 指標相結合，最終篩選出兩顆具變異性的天體，其中一顆分類為 contact binary ，另一顆則為未分類變星，根據推斷出的距離與自行運動數據，這兩顆天體均不支持其為 Pictor I 的成員星，應歸類為銀河系的前景場星。由此觀測結果，本研究推論 Pictor I 缺乏 RR Lyrae，Pictor I 的絕對 V 波段星等更接近 M_V ≈ −2.05 mag。;Ultra-faint dwarf (UFD) galaxies are relics of the early Universe， and their low luminosities make it difficult to confirm their distances and nature. RR Lyrae stars， as standard candles， provide a powerful means of obtaining independent distance estimates. In this work， we conducted a variability search for the UFD candidate Pictor I using archival multiband (g， r， i， z) time-series imaging taken data from the DECam. Compared with similar studies of UFD candidates， this dataset offers denser temporal coverage， with up to 51 epochs in the i-band. Candidate selection was performed by combining color–magnitude diagram (CMD) and filtering with a variability index. Two variable sources were identified: one classified as a contact binary and the other as an unclassified variable. Based on their inferred distance moduli and Gaia proper motions， neither object is consistent with membership in Pictor I， and both are likely foreground stars.We conclude PictorI is lack of RR Lyrae which help in constraing its absolute V-band magnitude as M_V =−2.05mag. <br> https://ir.lib.ncu.edu.tw/handle/987654321/109922 title: Comparison Analysis of gri-Band Period-Luminosity-Metallicity Relations and Sample Populations of RR Lyrae;Comparison Analysis of gri-Band Period-Luminosity-Metallicity Relations and Sample Populations of RR Lyrae abstract: 本研究針對數個天琴RR型變星的經驗週光-金屬豐度關係進行比較，藉以檢驗其在估算距離的可靠度與準確性。透過數組源於不同宿主系統──大麥哲倫星雲、天龍座矮星系、半人馬座$\omega$──之樣本，實際使用經驗週光-金屬豐度關係量測至宿主系統的距離模數，並與文獻提供之參考距離模數比較，評估各個週光-金屬豐度關係量測距離的表現。為深入了解不同經驗週光-金屬豐度關係的不一致與估算距離時的表現差異，並討論其本質原因，以統計學檢驗──二維度科摩哥洛夫-史密諾夫檢定、能量距離檢驗──比較各樣本的天琴RR型變星性質。此對於天琴RR變星週光關係的的綜合性測試，將提供對於在不同系統中該變星性質的了解，以避免未來校正新的週光-金屬豐度關係，或利用週光關係量測距離時產生系統性偏差。;We compared empirical period-luminosity-metallicity (PLZ) and period-Wesenheit index-metallicity (PWZ) relations of RR Lyrae stars to evaluate their validity and precision in distance estimation. Our analysis employs RR Lyrae samples from various host systems， including the Large Magellanic Cloud， Draco dwarf galaxy， and globular cluster $\omega$ Centauri. By comparing the inferred distances from different empirical relations with the independently established distance moduli of these systems， we evaluate the performance and consistency of empirical relations. To discuss the intrinsic factors that may contribute to discrepancies among the empirical relations and various behaviors in estimating distance， we compared the sampled population of RR Lyrae of each dataset using statistical tests， two dimensional Kolmogorov-Smirnov test and energy distance test. This comprehensive examination of RR Lyrae PLZ and PWZ relations provides insights that can help reduce systematic biases in future distance measurements obtained from surveys utilizing Sloan-like photometric filters. <br> https://ir.lib.ncu.edu.tw/handle/987654321/109918 title: DETECT：用於發現極端瞬變源的即時自動化系統;DETECT: A Real-Time Pipeline for the Discovery of Extreme Transients abstract: 大視野巡天計畫，例如：Pan-STARRS、ATLAS、ZTF等等，目前每日皆會回報大量的全新瞬變天體，然而其中僅有極小部分能獲得光譜後續觀測。本研究開發了 DETECT（DESI 與瞬變天體事件交叉比對工具，DESI and Transient Event Cross-matching Tool），這是一套自動化自動化程式系統，透過將新通報的瞬變天體與暗能量光譜儀（DESI）光譜資料庫中的宿主星系進行交叉比對，以提供快速的特徵以及宿主星系描述。DETECT 每日運行，自瞬變天體命名伺服器（Transient Name Server， TNS）接收通報，並辨識鄰近的 DESI 星系對應天體，藉此估計宿主紅移以及瞬變天體的絕對星等。 我們利用 2020 年至 2024 年的歷史數據評估此自動化流程系統，並成功為約 $15\%$ 的 TNS 樣本找回宿主星系的光譜紅移。基於此數據集，我們建構了一個包含 5，634 個瞬變天體的黃金樣本，其具備高品質的光變曲線並已透過 \texttt{Haffet} 套件完成處理。研究結果顯示，結合 WISE （廣域紅外線巡天探測衛星）中紅外線資訊與光學光度估值，能有效進行純光度法的高對比篩選，識別出本質極明亮（絕對星等 $M < -21$ mag）且亮度顯著超越其宿主星系的瞬變天體，進而篩選出極亮超新星（SLSN）並凸顯異常明亮的系統，包括候選的重力透鏡超新星（如 SN~2025wny）。 此外，透過將快速演化的瞬變天體候選者與千級新星（kilonova）模型及 AT~2017gfo 觀測基準進行比對，我們亦成功尋獲千級新星候選者 AT~2020bgp。DETECT 充分展現了在如薇拉·魯賓天文台時空遺產巡天（LSST）等新一代大規模巡天，歷史光譜資源將如何有力地支援瞬變天體快速分類、稀有事件識別以及族群統計研究。;Wide-field time-domain surveys now report large numbers of new transients each day， while spectroscopic follow-up remains available for only a small fraction of them. We present DETECT (DESI and Transient Event Cross-matching Tool)， an automated pipeline that provides rapid contextual characterization of newly reported transients by cross-matching them with host galaxies in the Dark Energy Spectroscopic Instrument (DESI) spectroscopic archive. DETECT operates daily， ingests reports from the Transient Name Server (TNS)， and identifies nearby DESI galaxy counterparts to estimate host redshifts and transient absolute magnitudes. We assess the pipeline using archival data from 2020 to 2024 and recover host spectroscopic redshifts for $\sim15\%$ of the TNS sample. From this data set， we construct a ``Gold Sample′′ of 5，634 transients with high-quality light curves processed using \texttt{Haffet}. We show that combining WISE mid-infrared information with optical luminosity estimates enables an efficient photometric high-contrast selection of intrinsically luminous transients ($M < -21$ mag) that substantially outshine their hosts， thereby isolating superluminous supernovae (SNe) and highlighting unusually bright systems， including candidate lensed SNe， such as SN~2025wny. By comparing fast transient candidates against kilonova models and the AT~2017gfo baseline， we also recover the kilonova candidate AT~2020bgp. DETECT demonstrates how archival spectroscopic resources can support transient classification， rare-event identification， and population studies in the era of large imaging surveys such as the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST). <br>