Search Publications
Prevalence of non-stationarity in quasi-periodic pulsations (QPPs) associated with M- and X-class solar flares
Hayes, L. A.; Broomhall, A. -M.; Mehta, T.
Quasi-periodic pulsations (QPPs) are frequently observed in solar and stellar flare emission, with recent studies suggesting that an increasing instantaneous period is a common characteristic of QPPs. Determining the prevalence of non-stationarity in QPPs contributes to a better understanding of which mechanism(s) is (are) responsible in QPP gener…
The Baryonic Content of Galaxies Mapped by MaNGA and the Gas Around Them
Bershady, Matthew A.; Wake, David A.; Lundgren, Britt +4 more
We analyze the cool gas in and around 14 nearby galaxies (at z < 0.1) mapped with the Sloan Digital Sky Survey IV MaNGA survey by measuring absorption lines produced by gas in spectra of background quasars/active galactic nuclei at impact parameters of 0-25 effective radii from the galactic centers. Using Hubble Space Telescope/Cosmic Origins S…
Constraining the Binarity of Black Hole Candidates: A Proof-of-concept Study of Gaia BH1 and Gaia BH2
Trani, Alessandro A.; Suto, Yasushi; Hayashi, Toshinori
Nearly a hundred binary black holes (BBHs) have been discovered with gravitational-wave signals emitted at their merging events. Thus, it is quite natural to expect that significantly more abundant BBHs with wider separations remain undetected in the Universe or even in our Galaxy. We consider a possibility that star-BH binary candidates may indee…
Energetic Neutral Atom (ENA) Emission Characteristics at the Moon and Mercury From 3D Regolith Simulations of Solar Wind Reflection
Wurz, P.; Fatemi, S.; Vorburger, A. +3 more
The reflection of solar wind protons as energetic neutral atoms (ENAs) from the lunar surface has regularly been used to study the plasma-surface interaction at the Moon. However, there still exists a fundamental lack of knowledge of the scattering process. ENA emission from the surface is expected to similarly occur at Mercury and will be studied…
3D Kinematics of Classical Cepheids According to Gaia EDR3 Catalog
Bobylev, V. V.; Bajkova, A. T.
The kinematics of about 2000 classical Cepheids of the Milky Way with data from Gaia EDR3 catalog has been studied. For some of these stars, there are line-of-sight velocities. On the basis of the nonlinear rotation model, the parameters of the rotation curve of the Galaxy were determined. The circular linear rotation velocity of the near-solar ne…
Rapid Variability of the Accretion Disk Wind in the Narrow-line Seyfert 1, PG 1448+273
Porquet, D.; Reeves, J. N.; Braito, V. +3 more
PG 1448+273 is a luminous, nearby (z = 0.0645), narrow-line Seyfert 1 galaxy, which likely accretes close to the Eddington limit. XMM-Newton observations of PG 1448+273 in 2017 revealed the presence of an ultrafast outflow, as seen through its blueshifted iron K absorption profile, with an outflow velocity of about 0.1 c. Here, the first NuSTAR ob…
Impact of M-dwarf stellar wind and photoevaporation on the atmospheric evolution of small planets
Estrela, Raissa; Valio, Adriana; Modi, Ashini
The evolution of a planet's atmosphere depends strongly on its host star's properties. When their host stars are younger, planets can experience stronger winds and extreme ultraviolet radiation (EUV) emissions. This is particularly true for planets orbiting M dwarfs due to their close proximity to the host star. To determine if these planets retai…
A precise blue-optical transmission spectrum from the ground: evidence for haze in the atmosphere of WASP-74b
Madhusudhan, Nikku; Constantinou, Savvas; Mancini, Luigi +5 more
We report transmission spectroscopy of the bloated hot Jupiter WASP-74b in the wavelength range from 4000 to 6200 Å. We observe two transit events with the Very Large Telescope (VLT) Focal Reducer and Spectrograph and present a new method to measure the exoplanet transit depth as a function of wavelength. The new method removes the need for a refe…
Neural Networks for Operational SYM-H Forecasting Using Attention and SWICS Plasma Features
Muñoz, Pablo; Cid, Consuelo; Collado-Villaverde, Armando
In this work, we present an Artificial Neural Network for operational forecasting of the SYM-H geomagnetic index up to 2 hr ahead using the Interplanetary Magnetic Field, the solar wind plasma features and previous SYM-H values. Former works that forecast the SYM-H index use data measured by ACE, in particular from the MAG and SWEPAM instruments. …
On the anticorrelation between pericentric distance and inner dark matter density of Milky Way's dwarf spheroidal galaxies
Battaglia, Giuseppina; Nipoti, Carlo; Di Cintio, Arianna +1 more
An anticorrelation between the central density of the dark matter (DM) halo (ρ150, DM) and the pericentric distances (rp) of the Milky Way's (MW's) dwarf spheroidal galaxies (dSphs) has been reported in the literature. The existence and origin of such anticorrelation are, however, controversial, one possibility being that onl…