Search Publications
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…
Dust-scattering Halo and Giant Hard X-Ray Flare from the Supergiant Fast X-Ray Transient IGR J16479-4514 Investigated with XMM-Newton and INTEGRAL
Tiengo, A.; Sidoli, L.; Bird, A. J. +1 more
We report results from the analysis of XMM-Newton and INTEGRAL data of IGR J16479-4514. The unpublished XMM-Newton observation, performed in 2012, occurred during the source eclipse. No pointlike X-ray emission was detected from the source; conversely, extended X-ray emission was clearly detected up to a size distance compatible with a dust-scatte…
Excitation Sources of Oscillations in Solar Coronal Loops: A Multi-wavelength Analysis
Conde C., Sandra M.; Jain, Rekha; Jatenco-Pereira, Vera
An investigation into the excitation sources of oscillations detected in a coronal loop structure is carried out using the images obtained with Interface Region Imaging Spectrometer (IRIS) and the Atmospheric Imaging Assembly (AIA) instrument on board the Solar Dynamics Observatory (SDO). A loop structure in the active region AR 11967 on 2014 Janu…
Unveiling the Hierarchical Structure of Open Star Clusters: The Perseus Double Cluster
Diaferio, Antonaldo; Li, Lu; Shao, Zhengyi +1 more
We introduce a new kinematic method to investigate the structure of open star clusters. We adopt a hierarchical clustering algorithm that uses the celestial coordinates and the proper motions of the stars in the field of view of the cluster to estimate a proxy of the pairwise binding energy of the stars and arrange them in a binary tree. The clust…