Search Publications
Dynamics of irregularly shaped cometary particles subjected to outflowing gas and solar radiative forces and torques
Bertini, Ivano; Fulle, Marco; Moreno, Fernando +6 more
The dynamics of irregularly shaped particles subjected to the combined effect of gas drag and radiative forces and torques in a cometary environment is investigated. The equations of motion are integrated over distances from the nucleus surface up to distances where the gas drag is negligible. The aerodynamic forces and torques are computed assumi…
The Extremely Buried Nucleus of IRAS 17208-0014 Observed at Submillimeter and Near-infrared Wavelengths
Onishi, Shusuke; Nakagawa, Takao; Baba, Shunsuke +6 more
The ultraluminous infrared galaxy IRAS 17208-0014 is a late-stage merger that hosts a buried active galactic nucleus (AGN). To investigate its nuclear structure, we performed high-spatial-resolution ( ~ 0.″04 ~ 32 pc) Atacama Large Millimeter/submillimeter Array (ALMA) observations in Band 9 (~450 µm or ~660 GHz), along with near-infrared AK…
Precise Evolutionary Asteroseismology of High-Amplitude δ Scuti Star AE Ursae Majoris
Fu, Jian-Ning; Xue, Hui-Fang; Niu, Jia-Shu
Stellar structure and evolution theory is one of the bases in modern astronomy. Stellar inner structures and their evolutionary states can be precisely tested by asteroseismology, since the inner information is brought to the stellar surface by the global oscillating waves and becomes observable. For stellar evolutionary speed (i.e., how long time…
Deblending Galaxies with Generative Adversarial Networks
Mobasher, Bahram; Rhodes, Jason; Hemmati, Shoubaneh +6 more
Deep generative models including generative adversarial networks (GANs) are powerful unsupervised tools in learning the distributions of data sets. Building a simple GAN architecture in PyTorch and training on the CANDELS data set, we generate galaxy images with the Hubble Space Telescope (HST) resolution starting from a noise vector. We proceed b…
Stellar masses of clumps in gas-rich, turbulent disc galaxies
Glazebrook, Karl; Lenkić, Laura; Fisher, Deanne B. +6 more
In this paper, we use Hubble Space Telescope/WFC3 observations of six galaxies from the DYnamics of Newly Assembled Massive Object (DYNAMO) survey, combined with stellar population modelling of the SED, to determine the stellar masses of DYNAMO clumps. The DYNAMO sample has been shown to have properties similar to z ≈ 1.5 turbulent, clumpy discs. …
Black hole spin measurements based on a thin disc model with finite thickness - I. An example study of MCG-06-30-15
Reynolds, Christopher S.; Abdikamalov, Askar B.; Bambi, Cosimo +1 more
We present a re-analysis of the XMM-Newton and NuSTAR observing campaigns for the well-studied, X-ray-bright AGN MCG-06-30-15. In particular, we consider a disc model with finite thickness. By fitting the disc reflection spectra in the data, we obtain a black hole spin of 0.87-0.99 (90 per cent confidence range) after taking the thickness of the d…
Multi-wavelength constraints on the outflow properties of the extremely bright millisecond radio bursts from the galactic magnetar SGR 1935 + 2154
Murase, Kohta; Kashiyama, Kazumi; Yamasaki, Shotaro
Extremely bright coherent radio bursts with millisecond duration, reminiscent of cosmological fast radio bursts, were codetected with anomalously-hard X-ray bursts from a Galactic magnetar SGR 1935 + 2154. We investigate the possibility that the event was triggered by the magnetic energy injection inside the magnetosphere, thereby producing magnet…
Shocks in the Outflow of the RS Oph 2021 Eruption Observed with X-Ray Gratings
Luna, G. J. M.; Della Valle, M.; Behar, E. +9 more
The 2021 outburst of the symbiotic recurrent nova RS Oph was observed with the Chandra High Energy Transmission Gratings (HETG) on day 18 after optical maximum and with XMM-Newton and its Reflection Grating Spectrographs (RGS) on day 21, before the supersoft X-ray source emerged and when the emission was due to shocked ejecta. The absorbed flux in…
What Determines Active Region Coronal Plasma Composition?
Long, David M.; Brooks, David H.; Baker, Deborah +4 more
The chemical composition of the solar corona is different from that of the solar photosphere, with the strongest variation being observed in active regions (ARs). Using data from the Extreme Ultraviolet (EUV) Imaging Spectrometer (EIS) on Hinode, we present a survey of coronal elemental composition as expressed in the first ionization potential (F…
Study of chemically peculiar stars - I. High-resolution spectroscopy and K2 photometry of Am stars in the region of M44
Bhatt, B. C.; García, R. A.; Lund, M. N. +30 more
We present a study based on the high-resolution spectroscopy and K2 space photometry of five chemically peculiar stars in the region of the open cluster M44. The analysis of the high-precision photometric K2 data reveals that the light variations in HD 73045 and HD 76310 are rotational in nature and caused by spots or cloud-like co-rotating struct…