Search Publications
A Search for Cloud Cores Affected by Shocked Carbon Chain Chemistry in L1251
Kim, Kee-Tae; Xu, Y.; Li, D. +26 more
We searched for shocked carbon chain chemistry (SCCC) sources with C3S abundances surpassing those of HC5N toward the dark cloud L1251, using the Effelsberg telescope at the K band (18-26 GHz). L1251-1 and L1251-3 are identified as the most promising SCCC sources. The two sources harbor young stellar objects. We conducted map…
Photometric Classifications of Evolved Massive Stars: Preparing for the Era of Webb and Roman with Machine Learning
Davenport, James R. A.; Dorn-Wallenstein, Trevor Z.; Levesque, Emily M. +1 more
In the coming years, next-generation space-based infrared observatories will significantly increase our samples of rare massive stars, representing a tremendous opportunity to leverage modern statistical tools and methods to test massive stellar evolution in entirely new environments. Such work is only possible if the observed objects can be relia…
Globular Cluster Systems of Massive Compact Elliptical Galaxies in the Local Universe: Evidence for Relic Red Nuggets?
Lee, Myung Gyoon; Kang, Jisu
Nearby massive compact elliptical galaxies (MCEGs) are strong candidates for relic galaxies (i.e., local analogs of red nuggets at high redshifts). It is expected that the globular cluster (GC) systems of relic galaxies are dominated by red (metal-rich) GCs. NGC 1277 is known as a unique example of such a galaxy in the previous study. In this stud…
Observational Evidence Points at AGB Stars as Possible Progenitors of CEMP-s and CEMP-r/s Stars
Goswami, Aruna; Purandardas, Meenakshi
The origin of enhanced abundance of heavy elements observed in the surface chemical composition of carbon-enhanced metal-poor (CEMP) stars still remains poorly understood. Here, we present detailed abundance analysis of seven CEMP stars based on high-resolution (R ~ 50,000) spectra that reveal enough evidence of asymptotic giant branch (AGB) stars…
Lessons from the First Multiply Imaged Supernova: Revised Strong-lensing Models for the Galaxy Cluster MACS J1149.5+2223
Zitrin, Adi
We present two grid-based lens models for the galaxy cluster MACS J1149.5+2223, concentrating on the properties of the first multiply imaged supernova Refsdal, which first appeared in this cluster as an Einstein cross (images S1-S4) around a cluster galaxy in late 2014, and about a year later as an additional image (SX) in a different image of the…
Local Environments of Low-redshift Supernovae
Sandstrom, Karin M.; Leroy, Adam K.; Koch, Eric W. +7 more
We characterize the local (2 kpc sized) environments of Type Ia, II, and Ib/c supernovae (SNe) that have recently occurred in nearby (d ≲ 50 Mpc) galaxies. Using ultraviolet (UV; from Galaxy Evolution Explorer) and infrared (IR; from Wide-field Infrared Survey Explorer) maps of 359 galaxies and a sample of 472 SNe, we measure the star formation ra…
Unexpected Short-period Variability in Dwarf Carbon Stars from the Zwicky Transient Facility
Roulston, Benjamin R.; Green, Paul J.; Hermes, J. J. +1 more
Dwarf carbon (dC) stars, main-sequence stars showing carbon molecular bands, are enriched by mass transfer from a previous asymptotic-giant-branch (AGB) companion, which has since evolved to a white dwarf. While previous studies have found radial-velocity variations for large samples of dCs, there are still relatively few dC orbital periods in the…
The Formation and Lifetime of Outflows in a Solar Active Region
Polito, Vanessa; Warren, Harry P.; Barczynski, Krzysztof +4 more
Active regions are thought to be one contributor to the slow solar wind. Upflows in EUV coronal spectral lines are routinely observed at their boundaries, and provide the most direct way for upflowing material to escape into the heliosphere. The mechanisms that form and drive these upflows, however, remain to be fully characterized. It is unclear …
The Dragonfly Wide Field Survey. II. Accurate Total Luminosities and Colors of Nearby Massive Galaxies and Implications for the Galaxy Stellar-mass Function
van Dokkum, Pieter; Conroy, Charlie; Abraham, Roberto +8 more
Stellar-mass estimates of massive galaxies are susceptible to systematic errors in their photometry, due to their extended light profiles. In this study, we use data from the Dragonfly Wide Field Survey to accurately measure the total luminosities and colors of nearby massive galaxies. The low surface brightness limits of the survey (µg…
Statistical Survey of Reservoir Phenomenon in Energetic Proton Events Observed by Multiple Spacecraft
Wang, Yang; Lyu, Dan; Xiao, Boxi +3 more
In this work, reservoir phenomenon in the decay phase of gradual solar energetic particle (SEP) events are investigated with two Helios and the IMP 8 spacecraft from 1976 January to 1980 March and two STEREO and the SOHO spacecraft from 2010 January to 2014 September. Using these data, 62 reservoir events of solar energetic protons were identified…