Search Publications
Dynamic Photometric Variability in Three Young Brown Dwarfs in Taurus: Detection of Optical Flares with TESS Data
Joshi, Santosh; Dutta, Somnath; Mondal, Soumen +4 more
We present I-band time-series photometric variability studies of three known nearby (∼140 pc) and young (∼1 Myr) brown dwarfs (BD) in the Taurus star-forming region in the Perseus molecular cloud. From 10 nights of observations over a time span of 10 yr, with a typical run of 3–6 hr each night, we estimated that the BDs show unstable short-scale p…
Statistics of the Interplanetary Magnetic Field from 0.1 to 30 au. I. Distribution Character
Zong, Qiugang; He, Jiansen; Yang, Liu +7 more
This study investigates the directional and intensity distributions of the interplanetary magnetic field (IMF) across a heliocentric distance range of approximately 0.1–30 au. Measurements from multiple spacecraft reveal that these distributions align closely with the Parker spiral configuration in general. Nevertheless, the deviation from the mod…
First Detection of Radio Emission from the Intermediate-mass Black Hole in POX 52: Deep Multiband Observations with ATCA and VLA
Guo, Hengxiao; Zhang, Ming; Wang, Yijun +14 more
We present the first multiband centimeter detection of POX 52, a nearby dwarf galaxy believed to harbor a robust intermediate-mass black hole. We conducted the deep observations using the Australia Telescope Compact Array (ATCA), spanning frequencies from 4.5 to 10 GHz, as well as the sensitive observations from the Karl G. Jansky Very Large Array…
Chandra Follow-up Observations of Swift-BAT-selected AGNs III
Marchesi, Stefano; Zhao, Xiurui; Ajello, Marco +5 more
The cosmic X-ray background (CXB) is dominated by the obscured and unobscured coronal light of active galactic nuclei (AGN). At energies below 10 keV, the CXB can be well explained by models taking into account the known AGN and the observed distribution of their obscuring, line-of-sight column densities, NH,l.o.s. However, at energies …
Geometrical Distances of Extragalactic Binaries through Spectroastrometry
Zhang, Zhi-Xiang; Wang, Jian-Min; Cai, Rong-Gen +4 more
The growing "Hubble tension" has prompted the need for precise measurements of cosmological distances. This paper demonstrates a purely geometric approach for determining the distances to extragalactic binaries through a joint analysis of spectroastrometry (SA), radial velocity (RV), and light-curve (LC) observations. A parameterized model for the…
A Systematic Search for Redback and Black Widow Candidates Based on the 4FGL-DR3 Unassociated Sources and the Zwicky Transient Facility Data
Lin, Jiamao; Ren, Liangliang; Lu, Chunyan +3 more
Spider pulsars represent a unique subclass of radio millisecond pulsars in binaries, and are further categorized into black widows and redbacks according to the mass of the low-mass companion. These pulsars, observable across multiple wavelengths, exhibit periodic variability in optical. The discovery and study of additional spider-type pulsars ar…
Can Active Galactic Nuclei Activity Be Enhanced by Ram Pressure Stripping?—X-Ray Perspective
Fossati, Matteo; Tiwari, Juhi; Sun, Ming +3 more
Ram pressure stripping (RPS) is an important process that plays a significant role in shaping the evolution of cluster galaxies and their surrounding environment. Despite its recognized significance, the potential connection between RPS and active galactic nuclei (AGN) activity in cluster galaxies remains poorly understood. Recent claims, based on…
Detectability of Solar Rotation Period across Various Wavelengths
Solanki, Sami K.; Vasilyev, Valeriy; Reinhold, Timo +3 more
The light curves of old G dwarfs obtained in the visible and near-infrared wavelength ranges are highly irregular. This significantly complicates the detectability of the rotation periods of stars similar to the Sun in large photometric surveys, such as Kepler and TESS. In this study, we show that light curves collected in the ultraviolet (UV) wav…
Improving the Temporal Resolution of SOHO/MDI Magnetograms of Solar Active Regions Using a Deep Generative Model
Xu, Yan; Wang, Haimin; Yurchyshyn, Vasyl +6 more
We present a novel deep generative model, named GenMDI, to improve the temporal resolution of line-of-sight (LOS) magnetograms of solar active regions (ARs) collected by the Michelson Doppler Imager (MDI) on board the Solar and Heliospheric Observatory. Unlike previous studies that focus primarily on spatial super-resolution of MDI magnetograms, o…
New Perspective on the Multiple-population Phenomenon in Galactic Globular Clusters from a Wide-field Photometric Survey
Milone, A. P.; Cordoni, G.; Marino, A. F. +10 more
Wide-field photometry of Galactic globular clusters (GCs) has been investigated to overcome limitations from the small field of view of the Hubble Space Telescope in the study of multiple populations. In particular, "chromosome maps" (ChMs) built with ground-based photometry were constructed to identify the first- and second-generation (1G and 2G)…