Search Publications
The Not So Simple Globular Cluster ω Cen. I. Spatial Distribution of the Multiple Stellar Populations
Rest, A.; Zenteno, A.; Saha, A. +8 more
We present a multi-band photometric catalog of ≈1.7 million cluster members for a field of view of ≈2° × 2° across ω Cen. Photometry is based on images collected with the Dark Energy Camera on the 4 m Blanco telescope and the Advanced Camera for Surveys on the Hubble Space Telescope. The unprecedented photometric accuracy and field coverage allowe…
Ion hole formation and nonlinear generation of electromagnetic ion cyclotron waves: THEMIS observations
Miyoshi, Yoshizumi; Kasahara, Satoshi; Asamura, Kazushi +6 more
Electromagnetic plasma waves are thought to be responsible for energy exchange between charged particles in space plasmas. Such an energy exchange process is evidenced by phase space holes identified in the ion distribution function and measurements of the dot product of the plasma wave electric field and the ion velocity. We develop a method to i…
Structured star formation in the Magellanic inter-Cloud region
Da Costa, G. S.; Belokurov, V.; Koposov, S. E. +5 more
We use a new contiguous imaging survey conducted using the Dark Energy Camera to investigate the distribution and properties of young stellar populations in the Magellanic inter-Cloud region. These young stars are strongly spatially clustered, forming a narrow chain of low-mass associations that trace the densest H I gas in the Magellanic Bridge a…
A low upper mass limit for the central black hole in the late-type galaxy NGC 4414
Krajnović, D.; Emsellem, E.; McDermid, R. M. +7 more
We present our mass estimate of the central black hole in the isolated spiral galaxy NGC 4414. Using natural guide star adaptive optics assisted observations with the Gemini Near-Infrared Integral Field Spectrometer (NIFS) and the natural seeing Gemini Multi-Object Spectrographs-North (GMOS), we derived two-dimensional stellar kinematic maps of NG…
Evidence for Relativistic Disk Reflection in the Seyfert 1h Galaxy/ULIRG IRAS 05189-2524 Observed by NuSTAR and XMM-Newton
Walton, Dominic J.; García, Javier A.; Harrison, Fiona A. +3 more
We present a spectral analysis of the NuSTAR and XMM-Newton observations of the Seyfert 1h galaxy/ULIRG IRAS 05189-2524 taken in 2013. We find evidence for relativistic disk reflection in the broadband X-ray spectrum: a highly asymmetric broad Fe Kα emission line extending down to 3 keV and a Compton scattering component above 10 keV. Physical mod…
Simultaneous Observations of p-mode Light Walls and Magnetic Reconnection Ejections above Sunspot Light Bridges
Hou, Yijun; Li, Ting; Yang, Shuhong +2 more
Recent high-resolution observations from the Interface Region Imaging Spectrograph reveal bright wall-shaped structures in active regions (ARs), especially above sunspot light bridges. Their most prominent feature is the bright oscillating front in the 1400/1330 Å channel. These structures are named light walls and are often interpreted to be driv…
The Three-part Structure of a Filament-unrelated Solar Coronal Mass Ejection
Chen, Y.; Li, B.; Song, H. Q. +6 more
Coronal mass ejections (CMEs) often exhibit the typical three-part structure in the corona when observed with white-light coronagraphs, I.e., the bright leading front, dark cavity, and bright core, corresponding to a high-low-high density sequence. As CMEs result from eruptions of magnetic flux ropes (MFRs), which can possess either lower (e.g., c…
A multiwavelength investigation of candidate millisecond pulsars in unassociated γ-ray sources
Greiner, J.; Belfiore, A.; Marelli, M. +7 more
About one-third of the 3033 γ-ray sources in the Third Fermi-LAT Gamma-ray Source Catalogue (3FGL) are unidentified and do not have even a tentative association with a known object; hence, they are defined as unassociated. Among Galactic γ-ray sources, pulsars represent the largest class, with over 200 identifications to date. About one-third of t…
NGC 741—Mergers and AGN Feedback on a Galaxy-group Scale
Giacintucci, S.; O'Sullivan, E.; David, L. +5 more
Low-mass galaxy cluster systems and groups will play an essential role in upcoming cosmological studies, such as those to be carried out with eROSITA. Though the effects of active galactic nuclei (AGNs) and merging processes are of special importance to quantify biases like selection effects or deviations from hydrostatic equilibrium, they are poo…
A Nonthermal Radio Filament Connected to the Galactic Black Hole?
Morris, Mark R.; Goss, W. M.; Zhao, Jun-Hui
Using the Very Large Array, we have investigated a nonthermal radio filament (NTF) recently found very near the Galactic black hole and its radio counterpart, Sgr A*. While this NTF—the Sgr A West Filament (SgrAWF)—shares many characteristics with the population of NTFs occupying the central few hundred parsecs of the Galaxy, the SgrAWF has the di…