Search Publications
Dry Merger Rate and Post-merger Fraction in the Coma Cluster Core
De Propris, Roberto; Jogee, Shardha; Weinzirl, Tim +3 more
We evaluate the dry merger activity in the Coma cluster, using a spectroscopically complete sample of 70 red-sequence (RS) galaxies, most of which (∼75%) are located within 0.2R200 (∼0.5 Mpc) from the cluster center, with data from the Coma Treasury Survey obtained with the Hubble Space Telescope. The fraction of close galaxy pairs in t…
Spectral Variations of the Sky: Constraints on Alternate Universes
Chary, R.
The fine tuning of parameters required to reproduce our present day universe suggests that our universe may simply be a region within an eternally inflating super-region. Many other regions beyond our observable universe would exist with each such region governed by a different set of physical parameters. Collision between these regions, if they o…
Searching for the HR 8799 Debris Disk with HST/STIS
Venn, K.; Matthews, B.; Lawler, S. +3 more
We present a new algorithm for space telescope high contrast imaging of close-to-face-on planetary disks called Optimized Spatially Filtered (OSFi) normalization. This algorithm is used on HR 8799 Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) coronagraphic archival data, showing an over-luminosity after reference star po…
Transport of Solar Wind H+ and He++ Ions across Earth’s Bow Shock
Liu, Y.; Dandouras, I.; Rème, H. +10 more
We have investigated the dependence of mass, energy, and charge of solar wind (SW) transport across Earth’s bow shock. An examination of 111 crossings during quiet SW in both quasi-perpendicular and quasi-parallel shock regions shows that 64 crossings had various degrees of heating and thermalization of SW. We found 22 crossings where the SW speed…
Ocular Shock Front in the Colliding Galaxy IC 2163
Brinks, Elias; Struck, Curtis; Elmegreen, Bruce G. +5 more
ALMA observations in the 12CO J=1\to 0 line of the interacting galaxy pair IC 2163 and NGC 2207 at 2″ × 1.″5 resolution reveal how the encounter drives gas to pile up in narrow, ∼1 kpc wide, “eyelids” in IC 2163. IC 2163 and NGC 2207 are involved in a grazing encounter, which has led to the development in IC 2163 of an eye-shaped (ocula…
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…