Search Publications
Understanding the mineralogy of a compositional anomaly north of the Korolev basin using Moon mineralogy mapper
Chaudhuri, N.; Kusuma, K. N.; Aravind Bharathvaj, S.
The work attempts to understand the mineralogy of the reported geochemical anomaly located in the north - northeast region of the Korolev basin using Moon Mineralogy Mapper (M3) onboard Chandrayaan -1 and other lunar datasets. To understand the mineralogy, colour composite images using integrated band depth parameters and mineral indice…
Far infrared properties of OH megamaser host galaxies
Wang, Jin; Lv, Bu-Hui; Lin, Ru-Qiu +8 more
The hosts of OH megamaser (OHM) are luminous infrared galaxies (LIRGs), in fact 1/3 of them are ultra-luminous infrared galaxies (ULIRGs), which imply that OHM phenomena should be related to the infrared radiation field. In this paper, we investigate the far infrared (FIR) properties of OHM host galaxies, through detailed infrared data covering br…
The X-ray activity of F stars with hot Jupiters: KELT-24 versus WASP-18
Micela, G.; Pillitteri, I.; Wolk, S. J. +1 more
X-rays emitted by the coronae of solar-type stars are a feature present in up to late-A types during the main sequence phase. F stars, either with or without hot Jupiters, are usually X-ray emitters. The very low level of X-ray emission of the F5 star WASP-18 despite its relatively young age and spectral type is thus quite peculiar. In this paper …
Origin and trends in NH4+ observed in the coma of 67P
Altwegg, K.; Goetz, C.; Rubin, M. +6 more
The European Space Agency/Rosetta mission escorted comet 67P/Churyumov-Gerasimenko and witnessed the evolution of its coma from low activity (~2.5-3.8 au) to rich ion-neutral chemistry (~1.2-2.0 au). We present an analysis of the ion composition in the coma, focusing on the presence of protonated high proton affinity (HPA) species, in particular $…
Decomposing the Spectrum of Ultraluminous X-Ray Pulsar NGC 300 ULX-1
Enoto, Teruaki; Noda, Hirofumi; Kobayashi, Shogo B. +3 more
A phase-resolved analysis on the X-ray spectrum of ultraluminous X-ray pulsar (ULXP) NGC 300 ULX-1 is performed with data taken with XMM-Newton and NuSTAR on 2016 December 16. In addition to the classical phase-restricting analysis, a method developed in active galactic nuclei studies is newly employed for ULXP. It has revealed that the pulsation …
Updated Radiative Transfer Model for Titan in the Near-infrared Wavelength Range: Validation against Huygens Atmospheric and Surface Measurements and Application to the Cassini/VIMS Observations of the Dragonfly Landing Area
Le Mouélic, S.; Cornet, T.; Rodriguez, S. +13 more
We present an analysis of Titan data acquired by the Cassini Visual and Infrared Mapping Spectrometer (VIMS) at the landing site of the Dragonfly mission, using a new version of our radiative transfer model for Titan, with significant updates for the spectroscopic parameters of atmospheric gases and photochemical aerosols. Our updated radiative tr…
The Association of Cusp-Aligned Arcs With Plasma in the Magnetotail Implies a Closed Magnetosphere
Dandouras, I.; Anderson, B. J.; Fazakerley, A. N. +7 more
We investigate a 15-day period in October 2011. Auroral observations by the Special Sensor Ultraviolet Spectrographic Imager instrument onboard the Defense Meteorological Satellite Program F16, F17, and F18 spacecraft indicate that the polar regions were covered by weak cusp-aligned arc (CAA) emissions whenever the interplanetary magnetic field (I…
Constraint on the Accretion of NGC 6946 X-1 Using Broadband X-Ray Data
Rana, Vikram; Ghosh, Tanuman
We analyze broadband X-ray data of NGC 6946 X-1 and probe plausible accretion scenarios in this ULX. NGC 6946 X-1 is a persistent soft source with broadband continuum spectra described by two thermal disk components. The cool accretion disk temperature T cool ~ 0.2 keV and the presence of a ~0.9 keV emission/absorption broad feature sug…
Sodium Abundances in Very Metal-poor Stars
Shi, Jianrong; Zhao, Gang; Li, Haining +9 more
Chemical composition of very metal-poor (VMP) stars can provide observational constraints on current models of nucleosynthesis and the chemical evolution of the Galaxy. It has been found that the scatter of [Na/Fe] versus [Fe/H] in VMP stars is very large in contrast with most other elements. Moreover, a negative slope in [Na/Fe] versus [Fe/H] was…
Integral Field Spectroscopy of the cometary starburst galaxy NGC 4861
Roche, Nathan; Sánchez, Sebastian F.; Vílchez, José M. +4 more
Using the PMAS Integral Field Unit on the Calar Alto 3.5 m telescope, we observed the southern component (Markarian 59) of the 'cometary' starburst galaxy NGC 4861. Mrk 59 is centred on a giant nebula and concentration of stars 1 kpc in diameter. Strong $\rm H\,\alpha$ emission points to a star-formation rate (SFR) at least 0.47 $\rm M_{\odot }\, …