Search Publications
Empirical Brightness Control and Equalization of Mars Context Camera Images
Robbins, Stuart J.; Kirchoff, Michelle R.; Hoover, Rachael H.
The Mars Reconnaissance Orbiter (MRO) spacecraft has been in orbit around Mars since March 2006. The Context Camera (CTX) on MRO has returned over 115,000 images of the planet at approximately 5-6 m per pixel, providing nearly global coverage. During that time, Mars has gone through nearly seven of its own years, changing solar distance from 1.38 …
Geometric Support for Dark Matter by an Unaligned Einstein Ring in A3827
Broadhurst, Tom; Oguri, Masamune; Chen, Mandy C. +4 more
The nondetection of dark matter (DM) particles in increasingly stringent laboratory searches has encouraged alternative gravity theories where gravity is sourced only from visible matter. Here, we consider whether such theories can pass a two-dimensional test posed by gravitational lensing—to reproduce a particularly detailed Einstein ring in the …
Stellar Variability in a Forming Massive Star Cluster
Andersen, Morten; Cheng, Yu; Tan, Jonathan
We present a near-infrared (NIR) variability analysis for a 6' × 6' region, which encompasses the massive protocluster G286.21+0.17. The total sample comprises more than 5000 objects, of which 562 show signs of a circumstellar disk based on their infrared colors. The data includes Hubble Space Telescope observations taken in two epochs separated b…
Co-evolution of nuclear rings, bars and the central intensity ratio of their host galaxies
Ravikumar, C. D.; Aswathy, S.
Using a sample of 13 early-type spiral galaxies hosting nuclear rings, we report remarkable correlations between the properties of the nuclear rings and the central intensity ratio (CIR) of their host galaxies. The CIR, a function of intensity of light within the central 1.5 and 3 arcsec region, is found to be a vital parameter in galaxy evolution…
The Energetics of Launching the Most Powerful Jets in Quasars: A Study of 3C 82
Berton, Marco; Zeimann, Greg; Hill, Gary J. +5 more
3C 82 at a redshift of 2.87 is the most distant 3C (Third Cambridge Catalogue) quasar. Thus, it is a strong candidate to have the most-luminous radio lobes in the universe. 3C 82 belongs to the class of compact steep-spectrum radio sources. We use single-dish and interferometric radio observations in order to model the plasma state of these powerf…
Spin clusters inside four young asteroid groups
Spoto, F.; Carruba, V.; Ramos, L. G. M.
Asteroid groups may either form because of collisions or because of spin induced fission. Recently it has been shown that young spin clusters tend to form more frequently in young collisional families than in older groups. Here, we study the occurrence of spin clusters inside four very recently identified asteroid groups: the (525) Adelaide, (2258…
Optical Studies of Eight AM Herculis-type Cataclysmic Variable Stars
Thorstensen, John R.; Buckley, David A. H.; Woudt, Patrick A. +2 more
We report detailed follow-up observations of eight cataclysmic variable stars (CVs) that are apparently AM Her stars, also called polars. For all, we either determine orbital periods for the first time or improve on existing determinations. The seven for which we have spectra show the high-amplitude radial-velocity curves and prominent He II λ4686…
Spectral energy distribution modeling of broadband emission in the pulsar wind nebula 3C 58
An, Hongjun; Kim, Seungjong
We investigate the broadband emission properties of the pulsar wind nebula (PWN) 3C 58 using a spectral energy distribution (SED) model. We attempt to match simultaneously the broadband SED and spatial variations of X‑ray emission in the PWN. We further use the model to explain a possible far‑IR feature of which a hint was recently suggested in 3C…
Multipoint Observations of Magnetosheath Response to Foreshock Transients
Wei, Xinhua; Cai, Chunlin
Multispacecraft observations of the magnetosheath responses to various foreshock transients in a single event on 17 March 2004 are reported in this paper. The Cluster spacecraft recorded long-standing large amplitude ULF waves with both compressive and transverse components in the magnetosheath. Additionally, two transient structures with depressi…
An Observational Test of Solar Plasma Heating by Magnetic Flux Cancellation
Park, Sung-Hong
Recent observations suggest that magnetic flux cancellation may play a crucial role in heating the Sun's upper atmosphere (chromosphere, transition region, corona). Here, we intended to validate an analytic model for magnetic reconnection and consequent coronal heating, driven by a pair of converging and canceling magnetic flux sources of opposite…