Search Publications
Evidence for a Close-in Tertiary Orbiting around the Algol-type System HZ Dra with Tidal Splitting and Spots Activities
Matekov, Azizbek; Li, Lin-Jia; Qian, Sheng-Bang +7 more
We report a cyclic variation of the O ‑ C diagram with a semiamplitude of 0.0033 days and a period of 1.05 yr for the pulsating eclipsing binary HZ Dra. The cyclic variation can be explained by the light travel-time effect via the presence of a close-in third body orbiting around HZ Dra in an elliptical orbit with a maximum semimajor axis of 0.89 …
High-latitude Observations of Dissipation-range Turbulence by the Ulysses Spacecraft during the Solar Minimum of 1993–96: The Spectral Break and Anisotropy
Isenberg, Philip A.; Schwadron, Nathan A.; Murphy, Neil +6 more
We examine Ulysses magnetic field observations from 1993 to 1996 as the spacecraft made its first fast-latitude scan from the southern to the northern hemisphere. Most of the observations we use are representative of high-latitude solar minimum conditions. We examine magnetic field power spectra characteristics of interplanetary turbulence at high…
Multispacecraft Observations of Protons and Helium Nuclei in Some Solar Energetic Particle Events toward the Maximum of Cycle 25
Ubertini, P.; Battiston, R.; Burger, W. J. +41 more
The intricate behavior of particle acceleration and transport mechanisms complicates the overall efforts in formulating a comprehensive understanding of solar energetic particle (SEP) events; these efforts include observations of low-energy particles (from tens of keV to hundreds of MeV) by space-borne instruments and measurements by the ground-ba…
Uncovering an Excess of X-Ray Point Sources in the Halos of Virgo Late-type Galaxies
Li, Zhiyuan; Hou, Meicun; Hu, Zhensong
We present a systematic search for extraplanar X-ray point sources around 19 late-type, highly inclined disk galaxies residing in the Virgo cluster, based on archival Chandra observations reaching a source detection sensitivity of L(0.5–8 keV) ∼ 1038 erg s‑1. Based on the cumulative source surface density distribution as a fu…
The Accelerating Decline of the Mass Transfer Rate in the Recurrent Nova T Pyxidis
Williams, Robert E.; Sion, Edward M.; Godon, Patrick +3 more
The recurrent nova T Pyxidis (T Pyx) has erupted six times since 1890, with its last outburst in 2011, and the relatively short recurrence time between classical nova explosions indicates that T Pyx must have a massive white dwarf (WD) accreting at a high rate. It is believed that, since its outburst in 1890, the mass transfer rate in T Pyx was ve…
Predicting the Energetic Proton Flux with a Machine Learning Regression Algorithm
Marcucci, Maria Federica; Laurenza, Monica; Benella, Simone +1 more
The need for real-time monitoring and alerting systems for space weather hazards has grown significantly in the last two decades. One of the most important challenges for space mission operations and planning is the prediction of solar proton events (SPEs). In this context, artificial intelligence and machine learning techniques have opened a new …
Serendipitous Catch of a Giant Jellyfish: An Ionized Nebula around 3C 275.1 with 170 kpc Long Tails
Li, Zhenzhen; Wang, Junfeng; Zhao, Qinyuan
3C 275.1 is a blue quasar at z = 0.55522, hosting powerful outflows and residing in a complex environment. We present a serendipitously detected giant nebula surrounding 3C 275.1, which shows morphological features resembling those of objects known as "jellyfish galaxies," with extremely long tails of ionized gas extending to 170 kpc in projection…
UOCS. XIII. Study of the Far-ultraviolet Bright Stars in the Open Cluster NGC 2420 Using AstroSat
Bisht, D.; Rangwal, Geeta; Dattatrey, Arvind K. +3 more
We present the study of four far-ultraviolet (FUV) bright stars in the field of the open cluster NGC 2420 using the Ultra Violet Imaging Telescope mounted on AstroSat. The three stars 525, 527, and 560 are members, while star 646 is a nonmember of the cluster. To characterize and determine the parameters of these stars, multiwavelength spectral en…
Astrometric Binary Classification via Artificial Neural Networks
Smith, Joe
With nearly two billion stars observed and their corresponding astrometric parameters evaluated in the recent Gaia mission, the number of astrometric binary candidates has risen significantly. Due to the surplus of astrometric data, the current computational methods employed to inspect these astrometric binary candidates are both computationally e…
Dust and Cold Gas Properties of Starburst HyLIRG Quasars at z ∼ 2.5
Neri, Roberto; Liu, Daizhong; Huang, Jia-Sheng +7 more
Some high-z active galactic nuclei (AGNs) are found to reside in extreme star-forming galaxies, such as hyperluminous infrared galaxies (HyLIRGs), with AGN-removed L IR of >1013 L ⊙. In this paper, we report NOEMA observations of six apparent starburst HyLIRGs associated with optical quasars at z ∼ 2–3 in the St…