Search Publications
Limits on X-Ray Polarization at the Core of Centaurus A as Observed with the Imaging X-Ray Polarimetry Explorer
Wu, Kinwah; Enoto, Teruaki; Turolla, Roberto +96 more
We present measurements of the polarization of X-rays in the 2-8 keV band from the nucleus of the radio galaxy Centaurus A (Cen A), using a 100 ks observation from the Imaging X-ray Polarimetry Explorer (IXPE). Nearly simultaneous observations of Cen A were also taken with the Swift, NuSTAR, and INTEGRAL observatories. No statistically significant…
The Astrophysical Distance Scale. V. A 2% Distance to the Local Group Spiral M33 via the JAGB Method, Tip of the Red Giant Branch, and Leavitt Law
Rousseau-Nepton, Laurie; Madore, Barry F.; Freedman, Wendy L. +6 more
The J-region asymptotic giant branch (JAGB) method is a new standard candle that is based on the stable intrinsic J-band magnitude of color-selected carbon stars, and has a precision comparable to other primary distance indicators such as Cepheids and the TRGB. We further test the accuracy of the JAGB method in the Local Group galaxy M33. M33's mo…
First Detection of Transverse Vertical Oscillation during the Expansion of Coronal Loops
Li, Dong; Zhang, Qingmin; Li, Chuan +3 more
In this Letter, we perform a detailed analysis of the M5.5 class eruptive flare occurring in active region 12,929 on 2022 January 20. The eruption of a hot channel generates a fast coronal mass ejection (CME) and a dome-shaped extreme-ultraviolet (EUV) wave at speeds of 740-860 km s-1. The CME is associated with a type II radio burst, i…
The JCMT BISTRO Survey: A Spiral Magnetic Field in a Hub-filament Structure, Monoceros R2
Zhang, Yapeng; Pattle, Kate; Karoly, Janik +157 more
We present and analyze observations of polarized dust emission at 850 µm toward the central 1 × 1 pc hub-filament structure of Monoceros R2 (Mon R2). The data are obtained with SCUBA-2/POL-2 on the James Clerk Maxwell Telescope (JCMT) as part of the B-fields in Star-forming Region Observations survey. The orientations of the magnetic field f…
Application of a Steady-state Accretion Disk Model to Spectrophotometry and High-resolution Spectra of Two Recent FU Ori Outbursts
Rodriguez, Antonio C.; Hillenbrand, Lynne A.
We apply a conventional accretion disk model to the FU Ori-type objects HBC 722 and Gaia 17bpi. Our base model is a steady-state, thin Keplerian disk featuring a modified Shakura-Sunyaev temperature profile, with each annulus radiating as an area-weighted spectrum given by a NextGen atmosphere at the appropriate temperature. We explore departures …
The Galactic Nova Rate: Estimates from the ASAS-SN and Gaia Surveys
Mukai, K.; Kochanek, C. S.; Hodgkin, S. T. +13 more
We present the first estimate of the Galactic nova rate based on optical transient surveys covering the entire sky. Using data from the All-Sky Automated Survey for Supernovae (ASAS-SN) and Gaia-the only two all-sky surveys to report classical nova candidates-we find 39 confirmed Galactic novae and 7 additional unconfirmed candidates discovered fr…
Total Solar Irradiance during the Last Five Centuries
Berrilli, Francesco; Bertello, Luca; Criscuoli, Serena +3 more
The total solar irradiance (TSI) varies on timescales of minutes to centuries. On short timescales it varies due to the superposition of intensity fluctuations produced by turbulent convection and acoustic oscillations. On longer timescales, it changes due to photospheric magnetic activity, mainly because of the facular brightenings and dimmings c…
Variation in Cosmic-Ray Intensity Lags Sunspot Number: Implications of Late Opening of Solar Magnetic Field
Li, Gang; Wang, Yuming; Guo, Jingnan +2 more
Galactic cosmic rays (GCRs), the highly energetic particles that may raise critical health issues for astronauts in space, are modulated by solar activity, with their intensity lagging behind the variation in sunspot number (SSN) by about one year. Previously, this lag has been attributed to the combined effect of outward convecting solar wind and…
Toward a Unified Explanation for the Three-part Structure of Solar Coronal Mass Ejections
Chen, Yao; Li, Leping; Song, Hongqiang
Coronal mass ejections (CMEs) are associated with the eruption of magnetic flux ropes (MFRs), which usually appear as hot channels in active regions and coronal cavities in quiet-Sun regions. CMEs often exhibit a classical three-part structure in the lower corona when imaged with white-light coronagraphs, including a bright front, dark cavity, and…
Mass Matters: No Evidence for Ubiquitous Lithium Production in Low-mass Clump Giants
Aguilera-Gómez, Claudia; Pinsonneault, Marc H.; Zinn, Joel C. +1 more
Known sources of lithium (Li) in the universe include the Big Bang, novae, asymptotic giant branch stars, and cosmic-ray spallation. During their longer-lived evolutionary phases, stars are not expected to add to the Li budget of the Galaxy, but to largely deplete it. In this context, recent analyses of Li data from GALAH and LAMOST for field red …