Search Publications
H1821+643: The Most X-Ray and Infrared Luminous Active Galactic Nucleus (AGN) in the Swift/BAT Survey in the Process of Rapid Stellar and Supermassive Black Hole Mass Assembly
Hashimoto, Takuya; Ricci, Claudio; Izumi, Takuma +6 more
H1821+643 is the most X-ray luminous nonbeamed active galactic nucleus (AGN) of L 14-150 keV = 5.2 × 1045 erg s-1 in the Swift/Burst Alert Telescope (BAT) ultrahard X-ray survey, and it is also a hyperluminous infrared (IR) galaxy L IR = 1013.2 L ⊙ residing in the center of a massiv…
Recent Formation of a Spiral Disk Hosting Progenitor Globular Clusters at the Center of the Perseus Brightest Cluster Galaxy. II. Progenitor Globular Clusters
Ohyama, Youichi; Lim, Jeremy; Wong, Emily +1 more
We address the nature and origin of super star clusters (SSCs) discovered by Holtzman et al. within a radius of ~5 kpc from the center of NGC 1275, the giant elliptical galaxy at the center of the Perseus Cluster. We show that, in contrast with the much more numerous population of SSCs subsequently discovered up to ~30 kpc from the center of this …
Long-term Evolution of Postexplosion Helium-star Companions of Type Iax Supernovae
Han, Zhanwen; McCully, Curtis; Heger, Alexander +3 more
Supernovae of Type Iax (SNe Iax) are an accepted faint subclass of hydrogen-free supernovae. Their origin, the nature of the progenitor systems, however, is an open question. Recent studies suggest that the weak deflagration explosion of a near-Chandrasekhar-mass white dwarf in a binary system with a helium-star donor could be the origin of SNe Ia…
Multispacecraft Remote Sensing and In Situ Observations of the 2020 November 29 Coronal Mass Ejection and Associated Shock: From Solar Source to Heliospheric Impacts
Liu, Ying D.; Zhu, Bei; Chen, Chong
We investigate the source eruption, propagation and expansion characteristics, and heliospheric impacts of the 2020 November 29 coronal mass ejection (CME) and associated shock, using remote sensing and in situ observations from multiple spacecraft. A potential-field source-surface model is employed to examine the coronal magnetic fields surroundi…
Magnetic Imprints of Eruptive and Noneruptive Solar Flares as Observed by Solar Dynamics Observatory
Ravindra, B.; Doddamani, V. H.; Vemareddy, P. +1 more
The abrupt and permanent changes of the photospheric magnetic field in the localized regions of active regions during solar flares, called magnetic imprints (MIs), have been observed for nearly the past three decades. The well-known coronal implosion model is assumed to explain such flare-associated changes but the complete physical understanding …
Toward Understanding the B[e] Phenomenon. IX. Nature and Binarity of MWC645
Miroshnichenko, A. S.; Manset, N.; Zharikov, S. V. +14 more
We present the results of optical and near-IR spectroscopy and multicolor photometry of the emission-line star MWC 645, which exhibits the B[e] phenomenon. The presence of positionally variable absorption lines of a cool star detected for the first time indicates that the object is a binary system. Using a combination of the photometric and spectr…
Study of Complex Absorption and Reflection in a Unique Intermediate Polar Paloma
Dutta, Anirban; Rana, Vikram
We present the broadband (0.3-40.0 keV) X-ray analysis of a unique intermediate polar Paloma using simultaneous data from XMM-Newton and NuSTAR observatories. The X-ray power spectra show strong modulations over orbital period compared to spin period. The orbit-folded light curves show a single broad hump-like structure with strong dips for soft t…
Using Single-view Observations of Cometary Plasma Tails to Infer Solar Wind Speed
Wang, Yuming; Li, Xiaolei; Cheng, Long
A comet plasma tail is a product of the interaction between the solar wind and the comet's coma, and has long been studied as a natural probe of the solar wind condition. We previously developed a method to derive the solar wind speed from dual-view observations of comet plasma tails. Here we improve the method to use single-view observations by a…
Study of the Mass-loss Rate from the Sun
Gopalswamy, Nat; Yashiro, Seiji; Michalek, Grzegorz
We investigate the temporal evolution of the yearly total mass-loss rate (YTMLR) from the Sun through coronal mass ejections (CMEs) over solar cycles 23 and 24. The mass determination of CMEs can be subject to significant uncertainty. To minimize this problem, we have used extensive statistical analysis. For this purpose, we employed data included…
Ultraviolet Observations of Comet 96/P Machholz at Perihelion
Raymond, J. C.; Bemporad, A.; Giordano, S. +2 more
Ultraviolet spectra of Comet 96/P Machholz were obtained during its 2002 perihelion with the UltraViolet Coronagraph Spectrometer instrument on board the SOHO satellite. Emission from H I, C II, C III, and O I is detected near the nucleus. The outgassing rate is in line with the value extrapolated from rates at larger distances from the Sun, and a…