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Spectroscopic Observations of a Coronal Loop: Basic Physical Plasma Parameters Along the Full Loop Length
Gupta, G. R.; Tripathi, Durgesh; Mason, Helen E.
Coronal loops are the basic structures of the solar transition region and corona. Understanding of the physical mechanisms behind the loop heating, plasma flows, and filling are still considered a major challenge in solar physics. The mechanism(s) should be able to supply mass to the corona from the chromosphere and to heat the plasma over 1 MK wi…
Quadrupole-octopole alignment of CMB related to the primordial power spectrum with dipolar modulation in anisotropic spacetime
Wang, Sai; Chang, Zhe; Li, Xin
The WMAP and Planck observations show that the quadrupole and octopole orientations of the CMB might align with each other. We reveal that the quadrupole-octopole alignment is a natural implication of the primordial power spectrum in an anisotropic spacetime. The primordial power spectrum is presented with a dipolar modulation. We obtain the privi…
A Theoretical Study on the Vibrational Spectra of Polycyclic Aromatic Hydrocarbon Molecules with Aliphatic Sidegroups
Zhang, Yong; Kwok, Sun; Sadjadi, SeyedAbdolreza
The role of aliphatic side groups in the formation of astronomical unidentified infrared emission (UIE) features is investigated by applying the density functional theory to a series of molecules with mixed aliphatic-aromatic structures. The effects of introducing various aliphatic groups to a fixed polycyclic aromatic hydrocarbon (PAH) core (oval…
The Recent Rejuvenation of the Sun's Large-scale Magnetic Field: A Clue for Understanding Past and Future Sunspot Cycles
Sheeley, N. R., Jr.; Wang, Y. -M.
The quiet nature of sunspot cycle 24 was disrupted during the second half of 2014 when the Sun’s large-scale field underwent a sudden rejuvenation: the solar mean field reached its highest value since 1991, the interplanetary field strength doubled, and galactic cosmic rays showed their strongest 27-day modulation since neutron-monitor observation…
First Detection of Thermal Radiojets in a Sample of Proto-brown Dwarf Candidates
Bouy, Hervé; Palau, Aina; Morata, Oscar +10 more
We observed with the Jansky Very Large Array at 3.6 and 1.3 cm a sample of 11 proto-brown dwarf (BD) candidates in Taurus in a search for thermal radio jets driven by the most embedded BDs. We detected for the first time four thermal radio jets in proto-BD candidates. We compiled data from UKIDSS, 2MASS, Spitzer, WISE, and Herschel to build the sp…
Characteristics of the dust trail of 67P/Churyumov-Gerasimenko: an application of the IMEX model
Srama, R.; Sommer, M.; Agarwal, J. +8 more
Context. Here we describe a new model of the dust streams of comet 67P/Churyumov-Gerasimenko that has been developed using the Interplanetary Meteoroid Environment for Exploration (IMEX). This is a new universal model for recently created cometary meteoroid streams in the inner solar system.
Aims: The model can be used to investigate characte…
Variations in High Degree Acoustic Mode Frequencies of the Sun during Solar Cycles 23 and 24
Hill, F.; Jain, K.; Tripathy, S. C.
We examine continuous measurements of the high-degree acoustic mode frequencies of the Sun covering the period from 2001 July to 2014 June. These are obtained through the ring-diagram technique applied to the full-disk Doppler observations made by the Global Oscillation Network Group. The frequency shifts in the degree range of 180 ≤slant {\ell } …
A non-LTE analysis of the hot subdwarf O star BD+28°4211. II. The optical spectrum
Latour, M.; Green, E. M.; Fontaine, G. +1 more
We present the second part of our detailed analysis of the hot subdwarf O (sdO) and spectroscopic standard star BD+28°4211, in which we focus on the optical spectrum. This target was selected to revisit the more general question of how reliably the atmospheric parameters of a very hot star can be inferred from optical spectroscopy alone. Given its…
The GALEX Ultraviolet Virgo Cluster Survey (GUViCS). V. Ultraviolet diffuse emission and cirrus properties in the Virgo cluster direction
Bianchi, S.; Duc, P. -A.; Boselli, A. +9 more
Context. The Virgo direction has been observed at many wavelengths in recent years, in particular in the ultraviolet with GALEX. The far ultraviolet (FUV) diffuse light detected by GALEX offers interesting information on the large scale distribution of Galactic dust, owing to the GALEX FUV band sensitivity and resolution.
Aims: We aim to char…
The 11.2 µm emission of PAHs in astrophysical objects
Sarre, P. J.; Candian, A.
The 11.2-µm emission band belongs to the family of the `unidentified' infrared emission bands seen in many astronomical environments. In this work, we present a theoretical interpretation of the band characteristics and profile variation for a number of astrophysical sources in which the carriers are subject to a range of physical conditions…