Search Publications
A Model for the Dust Envelope of the Silicate Carbon Star IRAS 09425-6040
Suh, Kyung-Won
IRAS 09425-6040 (I09425) is a silicate carbon star with conspicuous crystalline silicate and water-ice features and emission excesses in the far-infrared and millimeter (mm) wavelength ranges. To understand properties of the dust envelope of I09425, we propose a physical model based on the observations and known properties of asymptotic giant bran…
Water Masers in the Andromeda Galaxy. II. Where Do Masers Arise?
Darling, Jeremy; Amiri, Nikta
We present a comparative multiwavelength analysis of water-maser-emitting regions and non-maser-emitting luminous 24 µm star-forming regions in the Andromeda Galaxy (M31) to identify the sites most likely to produce luminous water masers useful for astrometry and proper motion studies. Included in the analysis are Spitzer 24 µm photome…
Interstellar Pickup Ion Production in the Global Heliosphere and Heliosheath
Wu, Y.; Guo, X.; Florinski, V.
Interstellar pickup ions (PUIs) play a significant part in mediating the solar wind (SW) interaction with the interstellar medium. In this paper, we examine the details of spatial variation of the PUI velocity distribution function (VDF) in the SW by solving the PUI transport equation. We assume the PUI distribution is isotropic resulting from str…
Trapping of Noble Gases by Radiative Association with H3 + in the Protosolar Nebula
Mousis, O.; Pauzat, F.; Bacchus-Montabonel, M. -C. +1 more
The heavy noble gas deficiencies observed in Titan’s atmosphere and in comets have been proposed to be related to a sequestration process by {{{H}}}3+ in the gas phase at the early protosolar nebula. Chemical thermodynamics and astrophysics modeling are favorable to this hypothesis, as presented in preceding papers. However, …
On the Chemistry of Hydrides of N Atoms and O+ Ions
Viti, Serena; Williams, David A.; Awad, Zainab
Previous work by various authors has suggested that the detection by Herschel/HIFI of nitrogen hydrides along the low-density lines of sight toward G10.6-0.4 (W31C) cannot be accounted for by gas-phase chemical models. In this paper we investigate the role of surface reactions on dust grains in diffuse regions, and we find that formation of the hy…
Measurements of the Soft Gamma-Ray Emission from SN2014J with Suzaku
Fukazawa, Y.; Takahashi, T.; Diehl, R. +9 more
The hard X-ray detector (HXD) on board Suzaku measured soft γ-rays from the SN Ia SN2014J at 77 ± 2 days after the explosion. Although the confidence level of the signal is about 90% (I.e., 2σ), the 3σ upper limit has been derived at <2.2 × 10-4 ph s-1 cm-2 in the 170-250 keV band as the first independent measur…
X-Ray Spectral and Temporal Analysis of Narrow Line Seyfert 1 Galaxy Was 61
Yuan, Weimin; Zhou, Hongyan; Wang, Ting-Gui +3 more
We present an analysis of spectrum and variability of the bright reddened narrow line Seyfert 1 galaxy Was 61 using 90 ks archival XMM-Newton data. The X-ray spectrum in 0.2-10 keV can be characterized by an absorbed power-law plus soft excess and an Fe Kα emission line. The power-law spectral index remains constant during the flux variation. The …
Transient X-Ray Source Population in the Magellanic-type Galaxy NGC 55
Jithesh, V.; Wang, Zhongxiang
We present the spectral and temporal properties of 15 candidate transient X-ray sources detected in archival XMM-Newton and Chandra observations of the nearby Magellanic-type, SB(s)m galaxy NGC 55. Based on an X-ray color classification scheme, the majority of the sources may be identified as X-ray binaries (XRBs), and six sources are soft, includ…
Photoionization Modeling of the Low-luminosity Seyfert 1 Nucleus in NGC 3516
Devereux, Nick
Spectroscopic observations of the low-luminosity Seyfert 1 nucleus in NGC 3516 obtained with the Hubble Space Telescope show that the visible spectrum is dominated by Balmer emission lines of hydrogen (H) and a continuum luminosity that rises into the UV. The anomalous {{H}}α /Hβ emission line ratio, the Balmer emission line luminosity, and the di…
Resolving Gas Flows in the Ultraluminous Starburst IRAS 23365+3604 with Keck LGSAO/OSIRIS
Martin, Crystal L.; Soto, Kurt T.
Keck OSIRIS/LGSAO observations of the ultraluminous galaxy IRAS 23365+3604 resolve a circumnuclear bar (or irregular disk) of semimajor axis 0.″42 (520 pc) in Paα emission. The line-of-sight velocity of the ionized gas increases from the northeast toward the southwest; this gradient is perpendicular to the photometric major axis of the infrared em…