Search Publications
Spatial Relationship between CMEs and Prominence Eruptions during SC 24 and SC 25
Gopalswamy, Nat; Yashiro, Seiji; Michalek, Grzegorz +2 more
During their propagation, coronal mass ejections (CMEs) and prominences sometimes display a nonradial motion. During the years after the solar minimum, the CME central position angle tended to be offset closer to the equator compared to that of the associated prominence eruptions (PE). No such effect was observed during solar maximum. The purpose …
A Temperature or Far-ultraviolet Tracer? The HNC/HCN Ratio in M83 on the Scale of Giant Molecular Clouds
Saito, Toshiki; Watanabe, Yoshimasa; Nishimura, Yuri +2 more
The HNC/HCN ratio is observationally known as a thermometer in Galactic interstellar molecular clouds. A recent study has alternatively suggested that the HNC/HCN ratio is affected by the ultraviolet (UV) field, not by the temperature. We aim to study this ratio on the scale of giant molecular clouds in the barred spiral galaxy M83 towards the sou…
Unveiling a Hidden Bar-like Structure in NGC 1087: Kinematic and Photometric Evidence Using MUSE/VLT, ALMA, and JWST
Lin, Lihwai; López-Cobá, Carlos; Sánchez, Sebastián F.
We report a faint nonaxisymmetric structure in NGC 1087 through the use of James Webb Space Telescope Near Infrared Camera, with an associated kinematic counterpart observed as an oval distortion in the stellar velocity map, Hα, and CO J = 2 → 1 velocity fields. This structure is not evident in the MUSE optical continuum images but only revealed i…
Do All the Quasars and High-excitation Radio Galaxies (HERGs) in the 3CRR Catalog Contain a Magnetically Arrested Disk (MAD)?
Li, Shuang-Liang; Cao, Xinwu; Zuo, Wenwen
Based on the magnetization, an accretion disk with a large-scale magnetic field can be separated into either standard and normal evolution or magnetically arrested disk (MAD), which are difficult to identify from observations. It is still unclear whether all the radio-loud active galactic nuclei (RLAGNs) with a thin disk and strong radio emissions…
A Massive White Dwarf or Low-mass Neutron Star Discovered by LAMOST
Liu, Jifeng; Wang, Song; Zhao, Xinlin +3 more
We report the discovery of a close binary J0606+2132 (Gaia DR3 3423365496448406272) with P obs = 2.77 days containing a possible massive white dwarf (WD) or a neutron star (NS) using LAMOST spectroscopic data. By a joint fitting of the radial velocity from LAMOST and the light curve from TESS, we derived a circular Keplerian orbit with …
A Search for Collisions and Planet–Disk Interactions in the Beta Pictoris Disk with 26 Years of High-precision HST/STIS Imaging
Stark, Christopher C.; Wagner, Kevin; Apai, Dániel +2 more
β Pictoris's well-studied debris disk and two known giant planets, in combination with the stability of the Hubble Space Telescope's Space Telescope Imaging Spectrograph (HST/STIS) (and now also JWST), offers a unique opportunity to test planet–disk interaction models and to observe recent planetesimal collisions. We present HST/STIS coronagraphic…
Near-infrared Spectroscopy of the Sun and Solar Analog Star HD 76151: Compiling an Extensive Line List in the Y, J, H, and K Bands
Bilir, Selçuk; Şahin, Timur; Şentürk, Sena Aleyna +2 more
Determining the physical nature of a star requires precise knowledge of its stellar atmospheric parameters, including effective temperature, surface gravity, and metallicity. This study presents a new atomic line list covering a broad spectral range (1–2.5 µm; YJHK bands) for iron (Fe) and α-elements (Ca, Mg, Ti, Si) to improve stellar param…
Millinovae: A New Class of Transient Supersoft X-Ray Sources without a Classical Nova Eruption
Udalski, Andrzej; Mróz, Przemek; Szymański, Michał K. +18 more
Some accreting binary systems containing a white dwarf (such as classical novae or persistent supersoft sources) are seen to emit low-energy X-rays with temperatures of ∼ 106 K and luminosities exceeding 1035 erg s‑1. These X-rays are thought to originate from nuclear burning on the white dwarf surface, either caus…
An Intermediate-mass Black Hole Hidden behind Thick Obscuration
Ricci, Claudio; Stern, Daniel; Pfeifle, Ryan W. +12 more
Recent models suggest approximately half of all accreting supermassive black holes (SMBHs; M BH ≳ 105 M ⊙) are expected to undergo intense growth phases behind Compton-thick (N H > 1.5 × 1024 cm‑2) veils of obscuring gas. However, despite being a viable source for the seeding of …
A Hot Mess: The Rich and Complex Soft Emitting Regions Surrounding the Reflection Dominated Flaring Central Engine of Mrk 1239
Komossa, S.; Gallo, L. C.; Grupe, D. +5 more
Previous X-ray works on Mrk 1239 have revealed a complex narrow-line Seyfert 1 that exhibits substantial absorption and strong emission from both collisionally ionized and photoionized plasmas. Here, we report on deep-pointed observations with XMM-Newton and NuSTAR, along with Swift monitoring, to understand the 0.3–30 keV continuum emission and t…