Search Publications
Freely Expanding Knots of X-Ray-emitting Ejecta in Kepler’s Supernova Remnant
Sato, Toshiki; Hughes, John P.
We report measurements of proper motion, radial velocity, and elemental composition for 14 compact X-ray-bright knots in Kepler’s supernova remnant (SNR) using archival Chandra data. The knots with the highest speed show both large proper motions (µ ∼ 0.″11-0.″14 yr-1) and high radial velocities (v ∼ 8700-10,020 km s-1)…
The Betelgeuse Project: constraints from rotation
Zhou, L.; Wheeler, J. Craig; Nance, S. +6 more
In order to constrain the evolutionary state of the red supergiant Betelgeuse (α Orionis), we have produced a suite of models with zero-age main sequence masses from 15 to 25 M⊙ in intervals of 1 M⊙ including the effects of rotation. The models were computed with the stellar evolutionary code MESA. For non-rotating models, we…
A Statistical Analysis of the Solar Phenomena Associated with Global EUV Waves
Long, D. M.; Carley, E. P.; Pérez-Suárez, D. +2 more
Solar eruptions are the most spectacular events in our solar system and are associated with many different signatures of energy release including solar flares, coronal mass ejections, global waves, radio emission and accelerated particles. Here, we apply the Coronal Pulse Identification and Tracking Algorithm (CorPITA) to the high-cadence synoptic…
Non-minimal derivative coupling scalar field and bulk viscous dark energy
Mostaghel, Behrang; Moshafi, Hossein; Movahed, S. M. S.
Inspired by thermodynamical dissipative phenomena, we consider bulk viscosity for dark fluid in a spatially flat two-component Universe. Our viscous dark energy model represents phantom-crossing which avoids big-rip singularity. We propose a non-minimal derivative coupling scalar field with zero potential leading to accelerated expansion of the Un…
The molecular gas mass of M 33
Boquien, M.; Braine, J.; Calzetti, D. +15 more
Do some environments favor efficient conversion of molecular gas into stars? To answer this, we need to be able to estimate the H2 mass. Traditionally, this is done using CO observations and a few assumptions but the Herschel observations which cover the far-IR dust spectrum make it possible to estimate the molecular gas mass independen…
On the Statistical Properties of the Lower Main Sequence
Basu, Sarbani; Hekker, Saskia; Bellinger, Earl P. +1 more
Astronomy is in an era where all-sky surveys are mapping the Galaxy. The plethora of photometric, spectroscopic, asteroseismic, and astrometric data allows us to characterize the comprising stars in detail. Here we quantify to what extent precise stellar observations reveal information about the properties of a star, including properties that are …
Water isotopologues in the circumstellar envelopes of M-type AGB stars
Olofsson, H.; Decin, L.; Lombaert, R. +3 more
Aims: In this study we intend to examine rotational emission lines of two isotopologues of water: H217O and H218O. By determining the abundances of these molecules, we aim to use the derived isotopologue - and hence oxygen isotope - ratios to put constraints on the masses of a sample of M-type AGB s…
Weak lensing and spectroscopic analysis of the nearby dissociative merging galaxy cluster Abell 3376
Durret, F.; Cypriano, E. S.; Laganá, T. F. +5 more
The galaxy cluster Abell 3376 is a nearby (\bar{z}=0.046) dissociative merging cluster surrounded by two prominent radio relics and showing an X-ray comet-like morphology. The merger system is comprised of the subclusters A3376W and A3376E. Based on new deep multiwavelength large-field images and published redshifts, we bring new insights about th…
High-energy Gamma-Ray Activity from V404 Cygni Detected by AGILE during the 2015 June Outburst
Verrecchia, F.; Tavani, M.; Piano, G. +2 more
The AGILE satellite detected transient high-energy γ-ray emission from the X-ray binary V404 Cygni, during the 2015 June outburst observed in radio, optical, X-ray, and soft γ-ray frequencies. The activity was observed by AGILE in the 50-400 MeV energy band, between 2015 June 24 UT 06:00:00 and 2015 June 26 UT 06:00:00 (MJD 57197.25-57199.25), wit…
A Relationship Between the Solar Rotation and Activity Analysed by Tracing Sunspot Groups
Ruždjak, Domagoj; Brajša, Roman; Skokić, Ivica +2 more
The sunspot position published in the data bases of the Greenwich Photoheliographic Results (GPR), the US Air Force Solar Optical Observing Network and National Oceanic and Atmospheric Administration (USAF/NOAA), and of the Debrecen Photoheliographic Data (DPD) in the period 1874 to 2016 were used to calculate yearly values of the solar differenti…