Search Publications
Hubble Space Telescope Observations of Accretion-Induced Star Formation in the Tadpole Galaxy Kiso 5639
Rafelski, Marc; Elmegreen, Bruce G.; Gallagher, John S. +6 more
The tadpole galaxy Kiso 5639 has a slowly rotating disk with a drop in metallicity at its star-forming head, suggesting that star formation was triggered by the accretion of metal-poor gas. We present multi-wavelength Hubble Space Telescope Wide Field Camera 3 images of UV through I band plus Hα to search for peripheral emission and determine the …
Variations in Titan's dune orientations as a result of orbital forcing
Tokano, Tetsuya; Lucas, Antoine; Newman, Claire E. +6 more
Wind-blown dunes are a record of the climatic history in Titan's equatorial region. Through modeling of the climatic conditions associated with Titan's historical orbital configurations (arising from apsidal precessions of Saturn's orbit), we present evidence that the orientations of the dunes are influenced by orbital forcing. Analysis of 3 Titan…
Radio-optical galaxy shape correlations in the COSMOS field
Brown, Michael L.; Harrison, Ian; Tunbridge, Ben
We investigate the correlations in galaxy shapes between optical and radio wavelengths using archival observations of the Cosmic Evolution Survey (COSMOS) field. Cross-correlation studies between different wavebands will become increasingly important for precision cosmology as future large surveys may be dominated by systematic rather than statist…
The massive dark halo of the compact early-type galaxy NGC 1281
Gebhardt, Karl; van de Ven, Glenn; Husemann, Bernd +7 more
We investigate the compact, early-type galaxy NGC 1281 with integral field unit observations to map the stellar line-of-sight velocity distribution (LOSVD) out to five effective radii and construct orbit-based dynamical models to constrain its dark and luminous matter content. Under the assumption of mass-follows-light, the H-band stellar mass-to-…
Polarimetry observations of comets: Status, questions, future pathways
Hines, Dean C.; Levasseur-Regourd, Anny-Chantal
Polarimetric observations of comets have provided crucial insight into the composition and evolution of cometary dust particles. Herein, we present a brief overview of the polarization properties observed in comets, and some possible interpretations. We also discuss recent imaging polarimetry observations of C/2012 S1 (ISON) and 67P/Churyumov-Gera…
Kelvin–Helmholtz instability in an active region jet observed with Hinode
Srivastava, A. K.; Zhelyazkov, I.; Chandra, R.
Over past ten years a variety of jet-like phenomena were detected in the solar atmosphere, including plasma ejections over a range of coronal temperatures being observed as extreme ultraviolet (EUV) and X-ray jets. We study the possibility for the development of Kelvin–Helmholtz (KH) instability of transverse magnetohydrodynamic (MHD) waves travel…
The Kelvin-Helmholtz instability under Parker-Spiral Interplanetary Magnetic Field conditions at the magnetospheric flanks
Adamson, E.; Otto, A.; Nykyri, K.
We have generated fully three-dimensional, high-resolution magnetohydrodynamic (MHD) simulations of the Kelvin-Helmholtz (KH) Instability during Parker-Spiral Interplanetary Magnetic Field (IMF) conditions at the dawnside magnetospheric flank magnetopause. Results of these simulations show that, although the draping of a strong tangential magnetic…
Velocity resolved [C II] spectroscopy of the center and the BCLMP 302 region of M 33 (HerM 33es)
Braine, J.; Ossenkopf, V.; van der Werf, P. +8 more
Context. The forbidden fine structure transition of C+ at 158 µm is one of the major cooling lines of the interstellar medium (ISM).
Aims: We aim to understand the contribution of the ionized, atomic, and molecular phases of the ISM to the [C II] emission from clouds near the dynamical center and the BCLMP302 H II region in t…
The Electron Density in Explosive Transition Region Events Observed by IRIS
Young, P. R.; Doschek, G. A.; Warren, H. P.
We discuss the intensity ratio of the O IV line at 1401.16 Å to the Si IV line at 1402.77 Å in Interface Region Imaging Spectrograph (IRIS) spectra. This intensity ratio is important if it can be used to measure high electron densities that cannot be measured using line intensity ratios of two different O IV lines from the multiplet within the IRI…
Mildly obscured active galaxies and the cosmic X-ray background
Walter, R.; Esposito, V.
Context. The diffuse cosmic X-ray background (CXB) is the sum of the emission of discrete sources, mostly massive black-holes accreting matter in active galactic nuclei (AGN). The CXB spectrum differs from the integration of the spectra of individual sources, calling for a large population, undetected so far, of strongly obscured Compton-thick AGN…