Search Publications
Astrophysical Distance Scale. IV. Preliminary Zero-point Calibration of the JAGB Method in the HST/WFC3-IR Broad J-band (F110W) Filter
Madore, Barry F.; Freedman, Wendy L.; Lee, Abigail J.
We present an absolute calibration of the J-region Asymptotic Giant Branch (JAGB) method using published photometry of resolved stars in 20 nearby galaxies observed with the Hubble Space Telescope using the WFC3-IR camera and the F110W (broad J-band) filter. True distance moduli for each of the galaxies are based on the Tip of the Red Giant Branch…
Low-mass members of nearby young stellar moving groups from Gaia EDR3
Murphy, Simon J.; Song, Inseok; Lee, Jinhee
Gaia EDR3 offers greatly improved kinematics for nearby objects, including members of nearby young stellar moving groups (NYMGs). In this study, we aim to identify low-mass NYMG members (spectral types of M0 to mid-L) in Gaia EDR3. We calculated spatio-kinematic membership probabilities by utilizing a Bayesian membership probability calculation sc…
X-ray view of a merging supermassive black hole binary candidate SDSS J1430+2303: Results from the first ∼200 days of observations
Zheng, Zhen-Ya; Shu, Xinwen; Pan, Zhen +7 more
Context. Recently we discovered an unprecedented supermassive black hole binary (SMBHB) candidate in the nearby Seyfert galaxy SDSS J1430+2303, which is predicted to merge within three years. X-ray spectroscopy may bring unique kinematic evidence for the last inspiraling stage, when the binary is too close to allow each of them to hold an individu…
Polymeric jets throw light on the origin and nature of the forest of solar spicules
Korsós, Marianna B.; Liu, Jiajia; Erdélyi, Robertus +4 more
Spicules are plasma jets that are observed in the dynamic interface region between the visible solar surface and the hot corona. At any given time, it is estimated that about 3 million spicules are present on the Sun. We find an intriguing parallel between the simulated spicular forest in a solar-like atmosphere and the numerous jets of polymeric …
Changes in the Near-surface Shear Layer of the Sun
Basu, Sarbani; Antia, H. M.
We use helioseismic data obtained over two solar cycles to determine whether there are changes in the near-surface shear layer (NSSL). We examine this by determining the radial gradient of the solar rotation rate. The radial gradient itself shows a solar-cycle dependence, and the changes are more pronounced in the active latitudes than at adjoinin…
Sampling molecular gas in the Helix planetary nebula: Variation in HNC/HCN with UV flux
Kastner, J. H.; Alcolea, J.; Santander-García, M. +4 more
Context. Observations of molecular clouds, prestellar cores, and protoplanetary disks have established that the HNC/HCN ratio may be a potent diagnostic of molecular gas physical conditions. The processes that govern the relative abundances of these molecules nevertheless remain poorly understood.
Aims: We seek to exploit the wide range of UV…
Evidence for Corotation Origin of Super-metal-rich Stars in LAMOST-Gaia: Multiple Ridges with a Similar Slope in the ϕ versus L z Plane
Zhao, Gang; Chen, Yuqin; Zhang, Haopeng
Super-metal-rich (SMR) stars in the solar neighborhood are thought to be born in the inner disk and come to their present location by radial migration, which is most intense at the corotation resonance (CR) of the Galactic bar. In this work, we show evidence for the CR origin of SMR stars in the Large Sky Area Multi-Object Fiber Spectroscopic Tele…
Gaia EDR3 comparative study of protoplanetary disk fractions in young stellar clusters
Mendigutía, I.; Huélamo, N.; Solano, E. +4 more
Context. The lifetime of protoplanetary disks around young stars limits the timescale of planet formation. A disk dissipation timescale ≤10 Myr was inferred from surveys that count the relative number of stars with disks - the disk fraction - in young stellar clusters with different ages. However, most previous surveys focused on the compact regio…
Implications of Kappa Suprathermal Halo of the Solar Wind Electrons
Pierrard, Viviane; Lazar, Marian; Stverak, Stepan
The electron velocity distributions measured in-situ in space plasmas reveal two central populations, a low-energy and highly dense (quasi-)thermal core, and a more diffuse but hotter suprathermal halo. Even if the core contributes much more to the total number density than the suprathermal particles, the energetic electrons play an important role…
The Pulsating Helium-atmosphere White Dwarfs. I. New DBVs from the Sloan Digital Sky Survey
Kepler, S. O.; Hermes, J. J.; Bell, Keaton J. +4 more
We present a dedicated search for new pulsating helium-atmosphere (DBV) white dwarfs from the Sloan Digital Sky Survey using the McDonald 2.1 m Otto Struve Telescope. In total we observed 55 DB and DBA white dwarfs with spectroscopic temperatures between 19,000 and 35,000 K. We find 19 new DBVs and place upper limits on variability for the remaini…