Search Publications
White Dwarf Photospheric Abundances in Cataclysmic Variables. I. SS Aurigae and TU Mensae
Sion, Edward M.; Godon, Patrick
Chemical abundance studies of cataclysmic variables have revealed high nitrogen to carbon ratios in a number of cataclysmic variable white dwarfs (based on ultraviolet emission and absorption lines), as well as possible carbon deficiency in many secondaries (based on the absence of infrared CO absorption lines). These indicate that the accreted ma…
A Multi-instrument Study of the 2018 Hard-state-only Outburst of H1743-322
Stiele, H.; Kong, A. K. H.
Distinct changes of the spectral and variability properties observed in black hole transients during a bright outburst deliver insight into the evolution of the accretion flow and accretion geometry. We investigated NICER and Swift monitoring observations of H 1743-322 during its 2018 outburst as well as NuSTAR and XMM-Newton data. The observed ha…
The Encounter of the Parker Solar Probe and a Comet-like Object Near the Sun: Model Predictions and Measurements
Zong, Qiugang; He, Jiansen; Ip, Wing-Huen +15 more
The Parker Solar Probe (PSP) aims to explore the nascent solar wind close to the Sun. Meanwhile, PSP is also expected to encounter small objects like comets and asteroids. In this work, we survey the ephemerides to find the chance of a recent encounter and then model the interaction between released dusty plasmas and solar wind plasmas. On 2019 Se…
ALMA Observation of the Protoplanetary Disk around WW Cha: Faint Double-peaked Ring and Asymmetric Structure
Dong, Ruobing; Kataoka, Akimasa; Takami, Michihiro +13 more
We present Atacama Large Millimeter/submillimeter Array (ALMA) Band 6 observations of dust continuum emission of the disk around WW Cha. The dust continuum image shows a smooth disk structure with a faint (low-contrast) dust ring, extending from ∼40 au to ∼70 au, not accompanied by any gap. We constructed the simple model to fit the visibility of …
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…