Search Publications
New Clues to the Evolution of Dwarf Carbon Stars From Their Variability and X-Ray Emission
Roulston, Benjamin R.; Green, Paul J.; Anderson, Scott F. +6 more
As main-sequence stars with C > O, dwarf carbon (dC) stars are never born alone but inherit carbon-enriched material from a former asymptotic giant branch (AGB) companion. In contrast to M dwarfs in post-mass-transfer binaries, C2 and/or CN molecular bands allow dCs to be identified with modest-resolution optical spectroscopy, even a…
Near-infrared spectroscopy of extreme BAL QSOs from the QUBRICS bright quasar survey
Grazian, Andrea; Selvelli, Pierluigi; Boutsia, Konstantina +8 more
We report on the spectral confirmation of 18 quasi-stellar object (QSO) candidates from the QUasars as BRIght beacons for Cosmology in the Southern hemisphere (QUBRICS) survey, previously observed in the optical band, for which we acquired new spectroscopic data in the near-infrared band with the Folded-port InfraRed Echellette (FIRE) spectrograph…
Presupernova ultralight axionlike particles
Kotake, Kei; Takiwaki, Tomoya; Mori, Kanji
We calculate the production of ultralight axionlike particles (ALPs) in a nearby supernova progenitor. Once produced, ALPs escape from the star and a part of them is converted into photons during propagation in the Galactic magnetic field. It is found that the MeV photon flux that reaches Earth may be detectable by γ -ray telescopes for ALPs light…
Measuring the F-corona intensity through time correlation of total and polarized visible light images
Romoli, M.; Naletto, G.; Burtovoi, A. +4 more
We present a new correlation method for deriving the F-corona intensity distribution, which is based on the analysis of the evolution of the total and polarized visible light (VL) images. We studied the one-month variation profiles of the total and polarized brightness acquired with Large Angle Spectrometric COronagraph and found that in some regi…
Spectroscopic study of solar transition region oscillations in the quiet-Sun observed by IRIS using the Si IV spectral line
Srivastava, A. K.; Wang, T. J.; Kayshap, P. +3 more
In this paper, we use the Si IV 1393.755 Å spectral line observed by the Interface Region Imaging Spectrograph (IRIS) in the quiet-Sun (QS) to determine the physical nature of the solar transition region (TR) oscillations. We analyse the properties of these oscillations using wavelet tools (e.g. power, cross-power, coherence, and phase difference)…
A New Cold Stream near the Southern Galactic Pole
Zhao, Gang; Zhao, Jing-Kun; Yang, Yong +2 more
We report the discovery of a cold stream near the southern Galactic pole (dubbed as SGP-S) detected in Gaia Early Data Release 3. The stream is at a heliocentric distance of ~9.5 kpc and spans nearly 58° by 0.°6 on sky. The color-magnitude diagram of SGP-S indicates an old and metal-poor (age ~12 Gyr, [M/H] ~ -2.0 dex) stellar population. The stre…
Distribution and Morphology of Lava Tube Systems on the Western Flank of Alba Mons, Mars
Crown, David A.; Berman, Daniel C.; Scheidt, Stephen P.
Integrated analyses of Thermal Emission Imaging System (THEMIS) IR, Context Camera (CTX), and Mars Orbiter Laser Altimeter (MOLA) data sets have been used to characterize the western flank of the Martian volcano Alba Mons, which hosts a prominent population of lava tube systems. Identification and mapping of lava tube systems is based on both morp…
Observations of the Solar F-Corona from Space
Llebaria, A.; Lamy, P. L.; Gilardy, H.
We present a review of the observations of the solar F-corona from space with a special emphasis of the 25 years of continuous monitoring achieved by the LASCO-C2 and C3 coronagraphs. Our work includes images obtained by the navigation cameras of the Clementine spacecraft, the SECCHI/HI-1A heliospheric imager onboard STEREO-A, and the Wide Field I…
Effect of an Interplanetary Coronal Mass Ejection on Saturn's Radio Emission
Jackman, C. M.; Cecconi, B.; Sánchez-Cano, B. +2 more
The Saturn Kilometric Radiation (SKR) was observed for the first time during the flyby of Saturn by the Voyager spacecraft in 1980. These radio emissions, in the range of a few kHz to 1 MHz, are emitted by electrons travelling around auroral magnetic field lines. Their study is useful to understand the variability of a magnetosphere and its coupli…
Two-point Separation Functions for Modeling Wide Binary Systems in Nearby Dwarf Galaxies
Peñarrubia, Jorge; Koposov, Sergey E.; Walker, Matthew G. +1 more
We use a geometric method to derive (two-dimensional) separation functions among pairs of objects within populations of specified position function ${dN}/d{\boldsymbol{R}}$ . We present analytic solutions for separation functions corresponding to a uniform surface density within a circular field, a Plummer sphere (viewed in projection), and the mi…