Search Publications
A Comprehensive Study of Open Cluster Chemical Homogeneity Using APOGEE and Milky Way Mapper Abundances
Cunha, Katia; Souto, Diogo; Tayar, Jamie +4 more
Stars in an open cluster are assumed to have formed from a broadly homogeneous distribution of gas, implying that they should be chemically homogeneous. Quantifying the level to which open clusters are chemically homogeneous can therefore tell us about interstellar medium pollution and gas mixing in progenitor molecular clouds. Using Sloan Digital…
Spatial Variations of Dust Opacity and Grain Growth in Dark Clouds: L1689, L1709, and L1712
Chen, Xi; Jiang, Biwei; Zhao, He +2 more
The far-infrared (FIR) opacity of dust in dark clouds within the Ophiuchus molecular cloud is investigated through multiwavelength infrared observations from UKIDSS, Spitzer, and Herschel. Employing the infrared color excess technique with both near-infrared and mid-infrared photometric data, a high-resolution extinction map in the K band (A …
ALMA-LEGUS. II. The Influence of Subgalactic Environments on Molecular Cloud Properties
Grebel, Eva K.; Smith, Linda J.; Aloisi, Alessandra +24 more
We compare the molecular cloud properties in subgalactic regions of two galaxies, barred spiral NGC 1313, which is forming many massive clusters, and flocculent spiral NGC 7793, which is forming significantly fewer massive clusters despite having a similar star formation rate to NGC 1313. We find that there are larger variations in cloud propertie…
Braving the Storm: Quantifying Disk-wide Ionized Outflows in the Large Magellanic Cloud with ULLYSES
Choi, Yumi; Olsen, Knut; Roman-Duval, Julia +11 more
The Large Magellanic Cloud (LMC) is home to many H II regions, which may lead to significant outflows. We examine the LMC's multiphase gas (T∼104-5 K) in H I, S II, Si IV, and C IV using 110 stellar sight lines from the Hubble Space Telescope's Ultraviolet Legacy Library of Young Stars as Essential Standards program. We develop a contin…
JWST View of Four Infant Galaxies at z = 8.31–8.49 in the MACS J0416.1‑2403 Field and Implications for Reionization
Grogin, Norman A.; Hathi, Nimish P.; Koekemoer, Anton M. +35 more
New JWST/NIRCam wide-field slitless spectroscopy provides redshifts for four z > 8 galaxies located behind the lensing cluster MACS J0416.1‑2403. Two of them, "Y1" and "JD," have previously reported spectroscopic redshifts based on Atacama Large Millimeter/submillimeter Array measurements of [O III] 88 µm and/or [C II] 157.7 µm line…
The Molecular Clouds of M31
Forbrich, Jan; Lada, Charles J.; Petitpas, Glen +1 more
Deep interferometric observations of CO and dust continuum emission are obtained with the Submillimeter Array at 230 GHz to investigate the physical nature of the giant molecular cloud (GMC) population in the Andromeda galaxy (M31). We use J = 2 ‑ 1 12CO and 13CO emission to derive the masses, sizes, and velocity dispersions …
Magnetar as the Central Engine of AT2018cow: Optical, Soft X-Ray, and Hard X-Ray Emission
Dai, Zi-Gao; Li, Long; Zhong, Shu-Qing +3 more
AT2018cow is the most extensively observed and widely studied fast blue optical transient to date; its unique observational properties challenge all existing standard models. In this paper, we model the luminosity evolution of the optical, soft X-ray, and hard X-ray emission, as well as the X-ray spectrum of AT2018cow with a magnetar-centered engi…
The Magnetic Field in the Colliding Filaments G202.3+2.5
Liu, Tie; Liu, Junhao; Lu, Xing +19 more
We observe the magnetic field morphology toward a nearby star-forming filamentary cloud, G202.3+2.5, using James Clerk Maxwell Telescope/POL-2 850 µm thermal dust polarization observations with an angular resolution of 14.″4 (∼0.053 pc). The average magnetic field orientation is found to be perpendicular to the filaments, while showing diffe…
Discovery of a Dusty Yellow Supergiant Progenitor for the Type IIb SN 2017gkk
Niu, Zexi; Sun, Ning-Chen; Liu, Jifeng
Type IIb supernovae are an important subclass of stripped-envelope supernovae (SNe), which show H lines only at early times. Their progenitors are believed to contain a low-mass H envelope before explosion. This work reports the discovery of a progenitor candidate in preexplosion Hubble Space Telescope images for the Type IIb SN 2017gkk. With deta…
The Kraft Break Sharply Divides Low-mass and Intermediate-mass Stars
White, Russel J.; Beyer, Alexa C.
Main-sequence stars transition at mid-F spectral types from slowly rotating (cooler stars) to rapidly rotating (hotter stars), a transition known as the Kraft Break and attributed to the disappearance of the outer convective envelope, causing magnetic braking to become ineffective. To define this Break more precisely, we assembled spectroscopic me…