Search Publications
The Evolution of Stellar X-Ray Activity and Angular Momentum as Seen by eROSITA, TESS, and Gaia
Stassun, Keivan G.; Kounkel, Marina
We have assembled a sample of ∼8200 stars with spectral types F5V–M5V, all having directly measured X-ray luminosities from eROSITA and rotation periods from TESS and having empirically estimated ages via their membership in stellar clusters and groups identified in Gaia astrometry (ages 3–500 Myr). This is the largest such study sample yet assemb…
Thermal Evolution of an Active Region Through Quiet and Flaring Phases as Observed by NuSTAR, XRT, and AIA
Reeves, Katharine K.; Grefenstette, Brian W.; Shih, Albert Y. +6 more
Solar active regions (ARs) contain a broad range of temperatures, with the thermal plasma distribution often observed to peak in the few millions of kelvin. Differential emission measure (DEM) analysis can allow instruments with diverse temperature responses to be used in concert to estimate this distribution. Nuclear Spectroscopic Telescope ARray…
Constraining the Progenitor of the Nearby Type II-P SN 2024ggi with Environmental Analysis
Niu, Zexi; Sun, Ning-Chen; Liu, Jifeng +3 more
The progenitors of Type II-P supernovae (SN) have been confirmed to be red supergiants. However, the upper mass limit of the directly probed progenitors is much lower than that predicted by current theories, and the accurate determination of the progenitor masses is key to understand the final fate of massive stars. Located at a distance of only 6…
Active Galactic Nuclei in the Green Valley at z ∼ 0.7
Ji, Zhiyuan; Rieke, Marcia; Williams, Christina C. +5 more
We present near-infrared (NIR) spectroscopy using the MMT and Magellan infrared spectrograph for a sample of 29 massive galaxies (
Ongoing and Fossil Large-scale Outflows Detected in a High-redshift Radio Galaxy: [C II] Observations of TN J0924-2201 at z = 5.174
Imanishi, Masatoshi; Kohno, Kotaro; Schramm, Malte +13 more
We present Atacama Large Millimeter/submillimeter Array observations of the [C II] 158 µm line and the underlying continuum emission of TN J0924‑2201, which is one of the most distant known radio galaxies at z > 5. The [C II] line and 1 mm continuum emission are detected at the host galaxy. The systemic redshift derived from the [C II] li…
A Hot Core in the Group-dominant Elliptical Galaxy NGC 777
Babul, Arif; David, Laurence P.; O'Sullivan, Ewan +8 more
NGC 777 provides an example of a phenomenon observed in some group-central ellipticals, in which the temperature profile shows a central peak, despite the short central cooling time of the intragroup medium. We use deep Chandra X-ray observations of the galaxy, supported by uGMRT 400 MHz radio imaging, to investigate the origin of this hot core. W…
Toward a Live Homogeneous Database of Solar Active Regions Based on SOHO/MDI and SDO/HMI Synoptic Magnetograms. II. Parameters for Solar Cycle Variability
Wang, Ruihui; Jiang, Jie; Luo, Yukun
Solar active regions (ARs) determine solar polar fields and cause solar cycle variability within the framework of the Babcock–Leighton dynamo. The contribution of an AR to the polar field is measured by its dipole field, which results from flux emergence and subsequent flux transport over the solar surface. The dipole fields contributed by an AR b…
Giant Biconical Dust Filaments in the Starburst Galaxy NGC 1808
Veilleux, Sylvain; Kane, Rohan
We present the results from an analysis of multiwavelength archival data on the multiphase outflow in the starburst galaxy NGC 1808. We report the detection at 70 and 100 µm of dust filaments that extend up to ∼13 kpc from the galactic midplane and trace an edge-brightened biconical structure along the minor axis of the galaxy. The inner fil…
Pressure Balance and Energy Budget of the Nuclear Superbubble of NGC 3079
Sun, Wei; Ji, Li; Li, Jiang-Tao +1 more
Superbubbles in the nuclear region of galaxies could be produced by active galactic nuclei (AGN) or nuclear starburst via different driving forces. We report analysis of the multiwavelength data of the kiloparsec-scale nuclear superbubble in NGC 3079 in order to probe the mechanisms driving the expansion of the superbubble. Based on the Chandra X-…
Solar Type J Radio Bursts and the Associated Coronal Loop
Feng, S. W.; Misawa, H.; Xie, H. X.
The solar type J radio burst is a variant of type III bursts, which are a probe for understanding solar energetic electrons and local electron density. This study investigates a type J burst event on 2017 September 9. We have combined the data from the extreme-ultraviolet (EUV) imaging and the EUV Imaging Spectrometer (EIS) to analyze the event. W…