Search Publications
Rotating Filament in Orion B: Do Cores Inherit Their Angular Momentum from Their Parent Filament?
Mardones, Diego; Hsieh, Cheng-Han; Arce, Héctor G. +2 more
Angular momentum is one of the most important physical quantities that governs star formation. The initial angular momentum of a core may be responsible for its fragmentation, and can have an influence on the size of the protoplanetary disk. To understand how cores obtain their initial angular momentum, it is important to study the angular momentu…
Solar Origins of August 26, 2018 Geomagnetic Storm: Responses of the Interplanetary Medium and Equatorial/Low-Latitude Ionosphere to the Storm
Akala, A. O.; Oyedokun, O. J.; Amaechi, P. O. +3 more
This study investigates the solar origins of August 26, 2018 geomagnetic storm and the responses of the interplanetary medium and equatorial/low-latitude ionosphere to it. We used a multiinstrument approach, with observations right from the solar surface to the Earth. Our results showed that the G3 geomagnetic storm of August 26, 2018 was initiate…
The effects of surface fossil magnetic fields on massive star evolution - III. The case of τ Sco
Martins, F.; Meynet, G.; de Koter, A. +2 more
τ Sco, a well-studied magnetic B-type star in the Upper Sco association, has a number of surprising characteristics. It rotates very slowly and shows nitrogen excess. Its surface magnetic field is much more complex than a purely dipolar configuration which is unusual for a magnetic massive star. We employ the CMFGEN radiative transfer code to dete…
Swift/UVOT follow-up of gravitational wave alerts in the O3 era
Troja, E.; Cenko, S. B.; Sakamoto, T. +41 more
In this paper, we report on the observational performance of the Swift Ultra-violet/Optical Telescope (UVOT) in response to the gravitational wave (GW) alerts announced by the Advanced Laser Interferometer Gravitational Wave Observatory and the Advanced Virgo detector during the O3 period. We provide the observational strategy for follow-up of GW …
Linking the Sun to the Heliosphere Using Composition Data and Modelling
Del Zanna, Giulio; Wimmer-Schweingruber, Robert F.; Lynch, Benjamin J. +13 more
Our understanding of the formation and evolution of the corona and the heliosphere is linked to our capability of properly interpret the data from remote sensing and in-situ observations. In this respect, being able to correctly connect in-situ observations with their source regions on the Sun is the key for solving this problem. In this work we a…
First Comet Observations with NIRSPEC-2 at Keck: Outgassing Sources of Parent Volatiles and Abundances Based on Alternative Taxonomic Compositional Baselines in 46P/Wirtanen
Villanueva, Geronimo L.; Cochran, Anita L.; Bodewits, Dennis +18 more
A major upgrade to the NIRSPEC instrument at the Keck II telescope was successfully completed in time for near-infrared spectroscopic observations of comet 46P/Wirtanen during its exceptionally close flyby of Earth in 2018 December. These studies determined the abundances of several volatiles, including C2H2, C2H
Effective temperatures of red supergiants estimated from line-depth ratios of iron lines in the YJ bands, 0.97-1.32µm
Kobayashi, Naoto; Matsunaga, Noriyuki; Kawakita, Hideyo +10 more
Determining the effective temperatures (Teff) of red supergiants (RSGs) observationally is important in many fields of stellar physics and galactic astronomy, yet some significant difficulties remain as a result of the model uncertainty, which originates mainly in the extended atmospheres of RSGs. Here we propose a line-depth ratio (LDR…
High Mass-Ratio Binary Population in Open Clusters: Segregation of Early Type Binaries and an Increasing Binary Fraction with Mass
Jadhav, Vikrant V.; Subramaniam, Annapurni; Roy, Kaustubh +1 more
Binary stars play a vital role in astrophysical research, as a good fraction of stars are in binaries. Binary fraction (BF) is known to change with stellar mass in the Galactic field, but such studies in clusters require binary identification and membership information. Here, we estimate the total and spectral-type high-mass-ratio (HMR) BF (f
Solo dwarfs II: the stellar structure of isolated Local Group dwarf galaxies
Côté, P.; Battaglia, G.; Lewis, G. F. +5 more
The Solo (Solitary Local) Dwarf Galaxy survey is a volume-limited, wide-field g- and i-band survey of all known nearby (<3 Mpc) and isolated (>300 kpc from the Milky Way or M31) dwarf galaxies. This set of 44 dwarfs is homogeneously analysed for quantitative comparisons to the satellite dwarf populations of the Milky Way and M31. In this pap…
A Chandra and HST View of WISE-selected AGN Candidates in Dwarf Galaxies
Greene, Jenny E.; Hainline, Kevin N.; Stern, Daniel +2 more
Reliably identifying active galactic nuclei (AGNs) in dwarf galaxies is key to understanding black hole (BH) demographics at low masses and constraining models for BH seed formation. Here we present Chandra X-ray Observatory observations of 11 dwarf galaxies that were chosen as AGN candidates using Wide-field Infrared Survey Explorer (WISE) mid-in…