Search Publications
Progenitor mass constraints for the type Ib intermediate-luminosity SN 2015ap and the highly extinguished SN 2016bau
Filippenko, Alexei V.; Pandey, S. B.; Buckley, David A. H. +21 more
Photometric and spectroscopic analyses of the intermediate-luminosity Type Ib supernova (SN) 2015ap and of the heavily reddened Type Ib SN 2016bau are discussed. Photometric properties of the two SNe, such as colour evolution, bolometric luminosity, photospheric radius, temperature, and velocity evolution, are also constrained. The ejecta mass, sy…
Two Classes of Eruptive Events During Solar Minimum
Yeates, A. R.; Bhowmik, P.
During solar minimum, the Sun is relatively inactive with few sunspots observed on the solar surface. Consequently, we observe a smaller number of highly energetic events such as solar flares or coronal mass ejections (CMEs), which are often associated with active regions on the photosphere. Nonetheless, our magnetofrictional simulations during th…
Impact of magnetic activity on inferred stellar properties of main-sequence Sun-like stars
Chaplin, William J.; Basu, Sarbani; Miglio, Andrea +3 more
The oscillation frequencies observed in Sun-like stars are susceptible to being shifted by magnetic activity effects. The measured shifts depend on a complex relationship involving the mode type, the field strength, and spatial distribution of activity, as well as the inclination angle of the star. Evidence of these shifts is also present in frequ…
Astrometric radial velocities for nearby stars
Lindegren, Lennart; Dravins, Dainis
Context. Under certain conditions, stellar radial velocities can be determined from astrometry, without any use of spectroscopy. This enables us to identify phenomena, other than the Doppler effect, that are displacing spectral lines.
Aims: The change of stellar proper motions over time (perspective acceleration) is used to determine radial v…
Modelling heterogeneous dust particles: an application to cometary polarization
Halder, Prithish; Ganesh, Shashikiran
In this work, we introduce a comet dust model that incorporates multiple dust morphologies along with inhomogeneous mixture of silicate minerals and carbonaceous materials under power-law size distribution, to replicate the standard polarization-phase curve observed in several comets in the narrow-band continuum. Following the results from Rosetta…
Discovery of Double-ring Structure in the Supernova Remnant N103B: Evidence for Bipolar Winds from a Type Ia Supernova Progenitor
Acero, Fabio; Yamaguchi, Hiroya; Chu, You-Hua +1 more
The geometric structure of supernova remnants (SNR) provides a clue to unveiling the pre-explosion evolution of their progenitors. Here we present an X-ray study of N103B (0509-68.7), a Type Ia SNR in the Large Magellanic Cloud, that is known to be interacting with dense circumstellar matter (CSM). Applying our novel method for feature extraction …
Estimating the Contribution of Foreground Halos to the FRB 180924 Dispersion Measure
Simha, Sunil; Prochaska, J. Xavier; Ryder, Stuart D. +6 more
Fast radio burst (FRB) dispersion measures (DMs) record the presence of ionized baryons that are otherwise invisible to other techniques enabling resolution of the matter distribution in the cosmic web. In this work, we aim to estimate the contribution to FRB 180924 DM from foreground galactic halos. Localized by ASKAP to a massive galaxy, this si…
Deep Chandra observations of diffuse hot plasma in M83
Wang, Q. Daniel; Ji, Li; Bogdán, Ákos +1 more
It is widely believed that galaxy formation and evolution is regulated by stellar mechanical feedback in forms of fast stellar winds and supernova explosions. However, the coupling of this feedback with the interstellar medium remains poorly understood. We examine how the coupling may be traced by diffuse soft X-ray emission in M83 - a nearby face…
An Atacama Large Millimeter/submillimeter Array Survey of Chemistry in Disks around M4-M5 Stars
Pascucci, Ilaria; Wilner, David J.; Cleeves, L. Ilsedore +10 more
M-stars are the most common hosts of planetary systems in the Galaxy. Protoplanetary disks around M-stars thus offer a prime opportunity to study the chemistry of planet-forming environments. We present an Atacama Large Millimeter/submillimeter Array survey of molecular line emission toward a sample of five protoplanetary disks around M4-M5 stars …
Compact disks. An explanation to faint CO emission in Lupus disks
Williams, J. P.; Ansdell, M.; Facchini, S. +4 more
Context. ALMA disk surveys have shown that a large fraction of observed protoplanetary disks in nearby star-forming regions (SFRs) are fainter than expected in CO isotopolog emission. Disks not detected in 13CO line emission are also faint and often unresolved in the continuum emission at an angular resolution of around 0.2 arcsec.
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