Search Publications
Missions
Journals
Publication Years
Modeling the plasma composition of 67P/C-G at different heliocentric distances
Ahmed, Sana; Soni, Vikas
The Rosetta spacecraft accompanied the comet 67P/C-G for nearly 2 years, collecting valuable data on the neutral and ion composition of the coma. The Rosetta Plasma Consortium (RPC) provided continuous measurements of the in situ plasma density while ROSINA-COPS monitored the neutral composition. In this work, we aim to estimate the composition of…
Rapid Dimming Followed by a State Transition: A Study of the Highly Variable Nuclear Transient AT 2019avd over 1000+ Days
Gandhi, Poshak; Miller, Jon M.; Ji, Long +16 more
The tidal disruption of a star around a supermassive black hole (SMBH) offers a unique opportunity to study accretion onto an SMBH on a human timescale. We present results from our 1000+ days monitoring campaign of AT 2019avd, a nuclear transient with tidal-disruption-event-like properties, with NICER, Swift, and Chandra. Our primary finding is th…
No evidence for gamma-ray emission from the Sagittarius dwarf spheroidal galaxy
Calore, Francesca; Eckner, Christopher; Manconi, Silvia
More than a decade ago, the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope unveiled the existence of two gigantic gamma-ray lobes known as the Fermi bubbles. While their origin is still unknown, various studies identified intricate spectral and morphological structures within the bubbles. One peculiar region, the cocoon, has recen…
Comprehensive Analysis of a Filament-embedding Solar Active Region at Different Stages of Evolution
Li, Hui; Su, Yang; Li, Chuan +9 more
Active regions are the brightest structures seen in the solar corona, so their physical properties hold important clues to the physical mechanisms underlying coronal heating. In this work, we present a comprehensive study for a filament-embedding active region as determined from observations from multiple facilities including the Chinese Hα Solar …
The debiased morphological transformations of galaxies since z = 3 in CANDELS
Demarco, R.; Cerulo, P.; Salvador, D. +3 more
Context. Morphological quantitative measurements and visual-like classifications are susceptible to biases arising from the expansion of the Universe. One of these biases is the effect of cosmological surface brightness dimming (CSBD): the measured surface brightness of a galaxy decays with redshift as (1 + z)−4. This effect might lead …
The Components of Cepheid Systems: The FN Vel System
Mérand, Antoine; Evans, Nancy Remage; Anderson, Richard I. +8 more
Cepheid masses continue to be important tests of evolutionary tracks for intermediate-mass stars as well as important predictors of their future fate. For systems where the secondary is a B star, Hubble Space Telescope ultraviolet spectra have been obtained. From these spectra a temperature can be derived, and from this a mass of the companion M <…
Cosmological constraints from type-I radio-loud quasars
Chang, N.; Huang, L.; Tu, Z. Y. +3 more
We obtain a sample of 1192 type-I quasars with the UV-optical, radio, and x-ray waveband coverage, which combined with the data from Huang and Chang [Mon. Not. R. Astron. Soc. 515, 1358 (2022), 10.1093/mnras/stac1451] and other matching objects of SDSS-DR16 with FIRST, XMM-Newton, and Chandra Source Catalog, and a sample of 407 flat-spectrum radio…
Center-to-limb Variations in Solar Plage Using IRIS Observations
Young, Peter R.; Kayshap, Pradeep
The center-to-limb variations (CLV) of transition region line Gaussian fit parameters in solar plage are reported for the first time. The Si IV 1402.77 Å line observed by the Interface Region Imaging Spectrograph is used. The spectral intensity increases linearly from the disk center to the solar limb. Similarly, the nonthermal velocity also incre…
A Centiparsec-scale Compact Radio Core in the Nearby Galaxy M60
Yang, Jun; Liao, Mai; Dou, Liming +7 more
M60, an elliptical galaxy located 16.5 Mpc away, has an active nucleus with a very low luminosity and an extremely low accretion rate. Its central supermassive black hole (SMBH) has a mass of M BH ~ 4.5 × 109 M ⊙ and a Schwarzschild radius corresponding to R S ~ 5.4 µas. To investigate the nature o…
H2CO, O3, NH3, HCN, N2O, NO2, NO, and HO2 upper limits of detection in the Venus lower-mesosphere using SOIR on board Venus Express
Aoki, S.; Vandaele, A. C.; Trompet, L. +6 more
We report on mean upper limit number densities and volume concentrations of H2CO, O3, NH3, HCN, N2O, NO2, NO, and HO2 at the Venus terminator above the cloud layer, computed from the SOIR/Venus Express transmittances measured during hundreds of solar occultations. An unsuccessful at…