Search Publications
Continuum Enhancements, Line Profiles, and Magnetic Field Evolution during Consecutive Flares
Mathioudakis, Mihalis; Murabito, Mariarita; Guglielmino, Salvo L. +5 more
During solar flares, magnetic energy can be converted into electromagnetic radiation from radio waves to γ-rays. Enhancements in the continuum at visible wavelengths, as well as continuum enhancements in the FUV and NUV passbands, give rise to white-light flares. In addition, the strong energy release in these events can lead to the rearrangement …
XMM-Newton and NICER Measurement of the Rms Spectrum of the Millihertz Quasiperiodic Oscillations in the Neutron-star Low-mass X-Ray Binary 4U 1636-53
Altamirano, D.; Méndez, Mariano; Zhang, Guobao +4 more
We used two XMM-Newton and six Neutron Star Interior Composition Explorer observations to investigate the fractional rms amplitude of the millihertz quasiperiodic oscillations (mHz QPOs) in the neutron-star low-mass X-ray binary 4U 1636-53. We studied, for the first time, the fractional rms amplitude of the mHz QPOs versus energy in 4U 1636-53 dow…
Searching for Balmer-dominated Type Ia Supernova Remnants in M33
Chu, You-Hua; Li, Chuan-Jui; Lin, Chris Ding-Jyun +1 more
We searched for Balmer-dominated Type Ia supernova remnants (SNRs) in M33 by selecting thermal X-ray sources with ${L}_{{\rm{X}}}\geqslant 5\times {10}^{35}$ erg s-1, identifying associated Hα emission features, and checking their [S II] and [O III] emission properties. Our search did not find any Balmer-dominated Type Ia SNRs in M33. T…
The H I Structure of the Local Volume Dwarf Galaxy Pisces A
Peek, J. E. G.; Putman, Mary E.; Tollerud, Erik J. +2 more
Dedicated H I surveys have recently led to a growing category of low-mass galaxies found in the Local Volume. We present synthesis imaging of one such galaxy, Pisces A, a low-mass dwarf originally confirmed via optical imaging and spectroscopy of neutral hydrogen (H I) sources in the Galactic Arecibo L-band Feed Array H I survey. Using H I observa…
Testing the Cosmic Distance Duality Relation with the Latest Strong Gravitational Lensing and Type Ia Supernovae
Xia, Jun-Qing; Lyu, Meng-Zhen; Li, Zheng-Xiang
We perform a model-independent and comprehensive test on the cosmic distance duality relation (CDDR) by combining the latest observations of strong gravitational lensing (SGL) including a total of 161 well-measured systems from several surveys and observations of Type Ia supernovae (SNe Ia), I.e., the joint light-curve analysis of SNe Ia and the P…
Testing Comptonization as the Origin of the Continuum in Nonmagnetic Cataclysmic Variables: The Photon Index of X-Ray Emission
Maiolino, T.; Titarchuk, L.; Wang, W. +4 more
The X-ray spectra of nonmagnetic cataclysmic variables (nmCVs) in the ∼0.3-15 keV energy band have been described by either one or several optically thin thermal plasma components or by cooling flow models. We tested whether the spectral continuum in nmCVs could be successfully described by Comptonization of soft photons off hot electrons presente…
Identifying the 3FHL Catalog. IV. Swift Observations of Unassociated Fermi-LAT 3FHL Sources
Ajello, M.; Marchesi, S.; Kaur, A. +3 more
The Fermi Large Area Telescope (Fermi-LAT) 3FHL catalog is the latest catalog of >10 GeV sources and will remain an important resource for the high-energy community for the foreseeable future. Therefore, it is crucial that this catalog is made complete by providing associations for most sources. In this paper, we present the results of the X-ra…
Hubble Space Telescope Astrometry of the Metal-poor Visual Binary µ Cassiopeiae: Dynamical Masses, Helium Content, and Age
Schaefer, Gail H.; Bond, Howard E.; Gilliland, Ronald L. +1 more
µ Cassiopeiae is a nearby, high-velocity, metal-poor ([Fe/H] = -0.81) visual binary. We have used high-resolution imaging with the Hubble Space Telescope (HST), obtained over nearly two decades, to determine the period (21.568 yr) and precise orbital elements. Combining these with published ground- and space-based astrometry, we determined d…
Accretion and Intercycle Variations in the PMS Interacting Binary AK Sco
France, Kevin; Gómez de Castro, Ana I.; Vallejo, Juan Carlos +2 more
There are only a handful of known short-period pre-main-sequence spectroscopic binaries with significant accretion rates (Class II sources). AK Sco stands out in this list because the system is composed of two equal mass F5 stars in a highly eccentric orbit thus both stars get as close as 11 stellar radii at periastron passage. This configuration …
Penumbral Brightening Events Observed in AR NOAA 12546
Stangalini, Marco; Ermolli, Ilaria; Giorgi, Fabrizio +2 more
Penumbral transient brightening events have been attributed to magnetic reconnection episodes occurring in the low corona. We investigated the trigger mechanism of these events in active region NOAA 12546 by using multiwavelength observations obtained with the Interferometric Bidimensional Spectrometer, by the Solar Dynamics Observatory, the Inter…