Search Publications
A Chemo-dynamical Link between the Gjöll Stream and NGC 3201
Marshall, J. L.; Sneden, C.; Hansen, T. T. +4 more
Recent analysis of the second data release of Gaia has revealed a number of new stellar streams surrounding the Milky Way. It has been suggested that one of these streams, Gjöll, is associated with the globular cluster NGC 3201, but thus far the association has only been based on kinematics of the stream stars. In this work we identify five likely…
Low-level Carbon Monoxide Line Polarization in Two Protoplanetary Disks: HD 142527 and IM Lup
Li, Zhi-Yun; Teague, Richard; Looney, Leslie W. +2 more
Magnetic fields are expected to play an important role in accretion processes for circumstellar disks. However, measuring the magnetic field morphology is difficult, especially when given that polarimetric (sub)millimeter continuum observations may not trace the fields in most disks. The Goldreich-Kylafis effect suggests that line polarization is …
GeV γ-Ray Emission from M33 and Arp 299
Liu, Ruo-Yu; Zhang, Hai-Ming; Wang, Xiang-Yu +1 more
Star-forming galaxies are huge reservoirs of cosmic rays (CRs) and these CRs convert a significant fraction of their energy into γ-rays by colliding with the interstellar medium (ISM). Several nearby star-forming galaxies have been detected in GeV-TeV γ-rays. It is also found that the γ-ray luminosities in 0.1-100 GeV correlate well with indicator…
Angular Expansion of Nova Shells
Guerrero, M. A.; Toalá, J. A.; Santamaría, E. +4 more
Nova shells can provide important information on their distance, their interactions with circumstellar and interstellar media, and the evolution in morphology of the ejecta. We have obtained narrowband images of a sample of five nova shells, namely DQ Her, FH Ser, T Aur, V476 Cyg, and V533 Her, with ages ranging from 50 to 130 yr. These images hav…
The First Extensive Spectroscopic Study of Young Stars in the North America and Pelican Nebulae
Fang, Min; Herczeg, Gregory J.; Wang, Hongchi +5 more
We present a spectroscopic survey of over 3400 potential members in the North America and Pelican Nebulae (NAP) using several low-resolution (R ≈ 1300-2000) spectrographs: Palomar/Norris, WIYN/Hydra, Keck/DEep Imaging Multi-Object Spectrograph (DEIMOS), and the Multiple Mirror Telescope (MMT)/Hectospec. We identify 580 young stars as likely member…
A New Likely Redback Millisecond Pulsar Binary with a Massive Neutron Star: 4FGL J2333.1-5527
Strader, Jay; Dage, Kristen C.; Chomiuk, Laura +7 more
We present the discovery of a likely new redback millisecond pulsar (MSP) binary associated with the Fermi γ-ray source 4FGL J2333.1-5527. Using optical photometric and spectroscopic observations from the Southern Astrophysical Research telescope, we identify a low-mass, main-sequence-like companion in a 6.9 hr, highly inclined orbit around a susp…
The Importance of Star Formation Intensity in Lyα Escape from Green Pea Galaxies and Lyman Break Galaxy Analogs
Malhotra, Sangeeta; Butler, Nathaniel R.; Yang, Huan +2 more
We have studied ultraviolet images of 40 Green Pea galaxies and 15 local Lyman Break Galaxy Analogs to understand the relation between Lyα photon escape and central UV photometric properties. We measured star-formation intensity (SFI; star formation rate per unit area) from the central 250 pc region ( ${S}_{250\mathrm{pc}}$ ) using Cosmic Origins …
Photometric Redshift Estimation with Galaxy Morphology Using Self-organizing Maps
Cooray, Asantha; Häußler, Boris; Nayyeri, Hooshang +1 more
We use multiband optical and near-infrared photometric observations of galaxies in the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey to predict photometric redshifts using artificial neural networks. The multiband observations span from 0.39 to 8.0 µm for a sample of ∼1000 galaxies in the GOODS-S field for which robust size …
Stellar X-Ray Activity Across the Hertzsprung-Russell Diagram. I. Catalogs
Liu, Jifeng; Bai, Yu; Wang, Song +1 more
Stellar magnetic activity provides substantial information on the magnetic dynamo and the coronal heating process. We present a catalog of X-ray activity for about 6000 stars, based on the Chandra and Gaia DR2 data. We also classified more than 3000 stars as young stellar objects, dwarf stars, or giant stars. By using the stars with valid stellar …
Milky Way Subsystems from Globular Cluster Kinematics Using Gaia DR2 and HST Data
Bobylev, V. V.; Bajkova, A. T.; Carraro, G. +2 more
We employ Gaia DR2 proper motions for 151 Milky Way globular clusters (GCs) from Vasiliev in tandem with distances and line-of-sight velocities to derive their kinematical properties. To assign clusters to the Milky Way thick disk, bulge, and halo, we follow the approach of Posti et al., who distinguished among different Galactic stellar component…