Search Publications
The Distribution of Two Flapping Types of Magnetotail Current Sheet: Implication for the Flapping Mechanism
Petrukovich, A. A.; Wei, Y.; Dunlop, M. W. +6 more
Flapping motion of the current sheets of planetary magnetotails is a common dynamic phenomenon. Previous studies of the Earth's magnetotail suggest that its flapping motion has two forms, that is, kink-like flapping that can propagate as waves toward both flanks and steady flapping that moves up and down but does not propagate. Although some model…
Simultaneous broadband observations and high-resolution X-ray spectroscopy of the transitional millisecond pulsar PSR J1023+0038
D'Avanzo, P.; Campana, S.; Rea, N. +4 more
We report on the first simultaneous XMM-Newton, NuSTAR, and Swift observations of the transitional millisecond pulsar PSR J1023+0038 in the X-ray active state. Our multi-wavelength campaign allowed us to investigate with unprecedented detail possible spectral variability over a broad energy range in the X-rays, as well as correlations and lags amo…
Where Is the Flux Going? The Long-term Photometric Variability of Boyajian’s Star
Kochanek, C. S.; van Saders, Jennifer; Shappee, Benjamin J. +5 more
We present ∼800 days of photometric monitoring of Boyajian’s Star (KIC 8462852) from the All-Sky Automated Survey for Supernovae (ASAS-SN) and ∼4000 days of monitoring from the All Sky Automated Survey (ASAS). We show that from 2015 to the present the brightness of Boyajian’s Star has steadily decreased at a rate of 6.3 ± 1.4 mmag yr-1,…
High-Speed Solar Wind Streams and Geomagnetic Storms During Solar Cycle 24
Mavromichalaki, H.; Gerontidou, M.; Daglis, T.
An updated catalog is created of 303 well-defined high-speed solar wind streams that occurred in the time period 2009 - 2016. These streams are identified from solar and interplanetary measurements obtained from the OMNIWeb database as well as from the Solar and Heliospheric Observatory (SOHO) database. This time interval covers the deep minimum o…
SWIFT J1756.9-2508: spectral and timing properties of its 2018 outburst
Sanna, A.; Ferrigno, C.; Papitto, A. +8 more
We discuss the spectral and timing properties of the accreting millisecond X-ray pulsar SWIFT J1756.9-2508 observed by XMM-Newton, NICER, and NuSTAR during the X-ray outburst occurred in April 2018. The spectral properties of the source are consistent with a hard state dominated at high energies by a non-thermal power-law component with a cut-off …
The High-velocity Stars in the Local Stellar Halo from Gaia and LAMOST
Du, Cuihua; Li, Hefan; Liu, Shuai +2 more
Based on the first Gaia data release and spectroscopy from the LAMOST Data Release 4, we study the kinematics and chemistry of the local halo stars. The halo stars are identified kinematically with a relative speed of at least 220 km s-1 with respect to the local standard of rest. In total, 436 halo stars are identified. From this halo …
Calibration of colour gradient bias in shear measurement using HST/CANDELS data
Schrabback, T.; Hoekstra, H.; Maoli, R. +6 more
Accurate shape measurements are essential to infer cosmological parameters from large area weak gravitational lensing studies. The compact diffraction-limited point spread function (PSF) in space-based observations is greatly beneficial, but its chromaticity for a broad-band observation can lead to new subtle effects that could hitherto be ignored…
A Long Hard-X-Ray Look at the Dual Active Galactic Nuclei of M51 with NuSTAR
Harrison, F. A.; Hornschemeier, A. E.; Ptak, A. +14 more
We present a broadband X-ray spectral analysis of the M51 system, including the dual active galactic nuclei (AGNs) and several off-nuclear point sources. Using a deep observation by NuSTAR, new high-resolution coverage of M51b by Chandra, and the latest X-ray torus models, we measure the intrinsic X-ray luminosities of the AGNs in these galaxies. …
Identification of the central compact object in the young supernova remnant 1E 0102.2-7219
Ruiter, Ashley J.; Dopita, Michael A.; Ghavamian, Parviz +4 more
Oxygen-rich young supernova remnants1 are valuable objects for probing the outcome of nucleosynthetic processes in massive stars, as well as the physics of supernova explosions. Observed within a few thousand years after the supernova explosion2, these systems contain fast-moving oxygen-rich and hydrogen-poor filaments visibl…
Radio/X-ray monitoring of the broad-line radio galaxy 3C 382. High-energy view with XMM-Newton and NuSTAR
Bianchi, S.; Cappi, M.; Ponti, G. +14 more
We present the analysis of five joint XMM-Newton/NuSTAR observations, 20 ks each and separated by 12 days, of the broad-line radio galaxy 3C 382. The data were obtained as part of a campaign performed in September-October 2016 simultaneously with Very Long Baseline Array. The radio data and their relation with the X-ray ones will be discussed in a…