Search Publications
Is the M81 Fast Radio Burst Host Globular Cluster Special?
Vesperini, Enrico; Kundu, Arunav; Strader, Jay +5 more
We use multiband archival Hubble Space Telescope (HST) observations to measure the photometric and structural parameters of the M81 globular cluster (GC) that hosts the fast radio burst FRB 20200120E. Our best-fitting King model has an effective radius r h = 3.06 pc with a moderate King model concentration of c = 53, and an inferred c…
ALMA ACA Detection of Submillimeter Emission Associated with the Western Hot Spot of the Radio Galaxy Pictor A
Nakagawa, Takao; Baba, Shunsuke; Isobe, Naoki +4 more
In order to investigate the far-infrared excess detected from the western hot spot of the radio galaxy Pictor A with the Herschel observatory, submillimeter photometry is performed with the Atacama Compact Array (ACA) of the Atacama Large Millimeter/submillimeter Array at Band 8 with the reference frequency of 405 GHz. A submillimeter source is di…
A Multiwavelength Classification and Study of Red Supergiant Candidates in NGC 6946
Williams, Benjamin F.; Dolphin, Andrew; Girardi, Léo +3 more
We have combined resolved stellar photometry from Hubble Space Telescope (HST), Spitzer, and Gaia to identify red supergiant (RSG) candidates in NGC 6946, based on their colors, proper motions, visual morphologies, and spectral energy distributions. We start with a large sample of 17,865 RSG candidates based solely on HST near-infrared photometry.…
FAST Search for Circumstellar Atomic Hydrogen. II. Is BD+30°3639 an Interacting Planetary Nebula?
Zhang, Yong; Zhang, Chuan-Peng; Parker, Quentin A. +3 more
The young, compact, very high surface brightness but low excitation planetary nebula (PN) BD+30°3639 is one of the very few PNe that have been reported to exhibit the 21 cm H I emission line. As part of a long-term program to search for circumstellar atomic hydrogen, we observed the 21 cm feature toward BD+30°3639 with the Five-hundred-meter Apert…
Multipoint Observations of the Dynamics at an ICME Sheath-Ejecta Boundary
Pulkkinen, Tuija I.; Kilpua, Emilia K. J.; Good, Simon W. +3 more
The radial evolution of interplanetary coronal mass ejections (ICMEs) is dependent on their interaction with the ambient medium, which causes ICME erosion and affects their geoefficiency. Here, an ICME front boundary, which separates the confined ejecta from the mixed, interacted sheath-ejecta plasma upstream, is analyzed in a multipoint study exa…
Magnetohydrodynamic Shocks Revisited: Magnetically Constraining the Upstream Solar Wind Condition
Narita, Yasuhito; Schmid, Daniel
Magnetohydrodynamic (MHD) shocks are commonly found in various space and astrophysical systems. One often encounters the problem that only the magnetic field data are available when studying interplanetary shocks and planetary bow shocks in the solar system, and not the plasma data due to instrumental and/or telemetry limitations. We aim to reveal…
Derivation of Instrument Requirements for Polarimetry Using Mg, Fe, and Mn Lines between 250 and 290 nm
Judge, P. G.; Sainz Dalda, A.; de Wijn, A. G. +1 more
Judge et al. recently argued that a region of the solar spectrum in the near-UV between about 250 and 290 nm is optimal for studying magnetism in the solar chromosphere, due to an abundance of Mg II, Fe II, and Fe I lines that sample various heights in the solar atmosphere. In this paper, we derive requirements for spectropolarimetric instruments …
CAHA/PPAK Integral-field Spectroscopic Observations of M81. II. Testing Photoionization Models in a Spatially Resolved LINER
Li, Zhiyuan; García-Benito, Rubén; Li, Zongnan +1 more
The origin of the low-ionization nuclear emission-line region (LINER) prevalent in local galaxies and its relationship with supermassive black holes have been debated for decades. We perform a comprehensive evaluation of traditional photoionization models against the circumnuclear ionized gas in M81, for which recent CAHA/PPAK integral-field spect…
Temporal Behaviors of Magnetic Helicity Injections by Self and Mutual Sunspot Rotations
Shimizu, Toshifumi; Hasegawa, Takahiro
Magnetic helicity is a physical parameter used to quantify the complexity of magnetic fields, providing an indication of the energy state in the coronal magnetic structure. We investigate the temporal evolution of magnetic helicity and its relationship to the occurrence of a variety of flares in the solar active region NOAA 12297, which was well o…
Sparse Logistic Regression for RR Lyrae versus Binaries Classification
Bono, Giuseppe; Pasquato, Mario; Braga, Vittorio F. +4 more
RR Lyrae (RRL) stars are old, low-mass, radially pulsating variable stars in their core helium burning phase. They are popular stellar tracers and primary distance indicators since they obey well-defined period-luminosity relations in the near-infrared regime. Their photometric identification is not trivial; indeed, RRL star samples can be contami…