Search Publications
Subkiloparsec Scaling Relations between Hot Gas, Dense Gas, and Star Formation Rate in Five Nearby Star-forming Galaxies
Gao, Yu; Tan, Qing-Hua; Wang, Junfeng +3 more
Based on the newly acquired dense gas observations from the JCMT MALATANG survey and X-ray data from Chandra, we explore the correlation between hot gas and HCN J = 4 → 3 and HCO+ J = 4 → 3 emission for the first time at subkiloparsec scale of five nearby star-forming galaxies, namely M82, M83, IC 342, NGC 253, and NGC 6946. We find tha…
Detecting the Effect of Nonthermal Sources on the Warm-hot Galactic Halo
Das, Sanskriti
We report the first detection of nonthermal broadening of O VII lines in the warm-hot ≈106 K circumgalactic medium of the Milky Way. We use z = 0 absorption of O VII Kα, O VII Kβ, and O VIII Kα lines in archival grating data of b > 15° quasar sightlines from Chandra and XMM-Newton. Nonthermal line broadening is evident in two-thirds …
Mapping Multiphase Metals in Star-forming Galaxies: A Spatially Resolved UV+Optical Study of NGC 5253
Kumari, Nimisha; Hernandez, Svea; Aloisi, Alessandra +4 more
We present a pioneering, spatially resolved, multiphase gas abundance study on the blue compact dwarf galaxy NGC 5253, targeting 10 star-forming (SF) clusters inside six far-UV (FUV) Hubble Space Telescope/Cosmic Origins Spectrograph (COS) pointings with cospatial optical Very Large Telescope/MUSE observations throughout the galaxy. The SF regions…
Revisiting the Activity–Rotation Relation for Evolved Stars
Liu, Jifeng; Wang, Song; Li, Xue +2 more
The magnetic dynamo mechanism of giant stars remains an open question, which can be explored by investigating their activity–rotation relations with multiple proxies. By using the data from the LAMOST and Galaxy Evolution Explorer surveys, we carried out a comprehensive study of activity–rotation relations of evolved stars based on Ca II H and K l…
Detailed Study of Stars and Gas in a z = 8.3 Massive Merger with Extreme Dust Conditions
Harshan, Anishya; Tripodi, Roberta; Martis, Nicholas S. +15 more
We present galaxy MACS0416-Y1 at zspec = 8.312 as observed by the CAnadian NIRISS Unbiased Cluster Survey. MACS0416-Y1 has been shown to have extreme dust properties; thus, we study the physical properties and star formation histories of its resolved components. Overall, we find that MACS0416-Y1 is undergoing a star formation burst in t…
The Magellan M2FS Spectroscopic Survey of High-redshift Galaxies: The Brightest Lyman-break Galaxies at z ∼ 6
Jiang, Linhua; Ning, Yuanhang; Pan, Zhiwei +2 more
We present a study of a sample of 45 spectroscopically confirmed, UV luminous galaxies at z ∼ 6. They were selected as bright Lyman-break galaxies (LBGs) using deep multiband optical images in more than 2 deg2 of the sky, and subsequently identified via their strong Lyα emission. The majority of these LBGs span an absolute UV magnitude …
Comparison of the Chemical Compositions between the Bright and Faint Red Clumps for the Metal-poor and Metal-rich Populations in the Milky Way Bulge
Lee, Young-Wook; Hong, Seungsoo; Lim, Dongwook
We examined the double red clump (RC) observed in the Galactic bulge, interpreted as a difference in distance ("X-shaped bulge scenario") or in chemical composition ("multiple population scenario"). To verify chemical differences between the RC groups, we performed low-resolution spectroscopy for RC and red giant branch (RGB) stars using Gemini-So…
Data-driven Stellar Intrinsic Colors and Dust Reddenings for Spectrophotometric Data: From the Blue-edge Method to a Machine Learning Approach
Ren, Yi; Wang, Shu; Jiang, Biwei +4 more
Intrinsic colors (ICs) of stars are essential for studies on both stellar physics and dust reddening. In this work, we developed an XGBoost model to predict ICs with the atmospheric parameters T eff,
Identifying Plasma Fractionation Processes in the Chromosphere Using IRIS
Stangalini, Marco; Long, David M.; Testa, Paola +7 more
The composition of the solar corona differs from that of the photosphere, with the plasma thought to fractionate in the solar chromosphere according to the first ionization potential (FIP) of the different elements. This produces a FIP bias, wherein elements with a low FIP are preferentially enhanced in the corona compared to their photospheric ab…
The Star Formation History of Nearby Galaxies: A Machine Learning Approach
Tian, Hao; Yang, Ming; Liu, Chao +2 more
Reproducing color–magnitude diagrams (CMDs) of star-resolved galaxies is one of the most precise methods for measuring the star formation history (SFH) of nearby galaxies back to the earliest time. The upcoming big data era poses challenges to the traditional numerical technique in its capacity to deal with vast amounts of data, which motivates us…