Search Publications
Multiband Optical Observation of the P/2010 A2 Dust Tail
Hasegawa, Sunao; Usui, Fumihiko; Yoshida, Michitoshi +6 more
An inner main-belt asteroid, P/2010 A2, was discovered on 2010 January 6. Based on its orbital elements, it is considered that the asteroid belongs to the Flora collisional family, where S-type asteroids are common, while showing a comet-like dust tail. Although analysis of images taken by the Hubble Space Telescope and Rosetta spacecraft suggeste…
Discovery of the Host Cluster for the Fundamental Cepheid Calibrator Zeta Geminorum
Gieren, W.; Balam, D.; Lane, D. +2 more
New and existing CORAVEL, UBVJHKs , HST, HIP/Tycho, ARO, KPNO, and DAO observations imply that the fundamental Cepheid calibrator ζ Gem is a cluster member. The following parameters were inferred for ζ Gem from cluster membership and are tied to new spectral classifications (DAO) established for 26 nearby stars (e.g., HD53588/B7.5IV, HD…
An In-depth Study of the Abundance Pattern in the Hot Interstellar Medium in NGC 4649
Loewenstein, Michael; Davis, David S.
We present our X-ray imaging spectroscopic analysis of data from deep Suzaku and XMM-Newton Observatory exposures of the Virgo Cluster elliptical galaxy NGC 4649 (M60), focusing on the abundance pattern in the hot interstellar medium (ISM). All measured elements show a radial decline in abundance, with the possible exception of O. We construct ste…
The Size Difference between Red and Blue Globular Clusters is not due to Projection Effects
Sills, Alison; Harris, William E.; Webb, Jeremy J.
Metal-rich (red) globular clusters in massive galaxies are, on average, smaller than metal-poor (blue) globular clusters. One of the possible explanations for this phenomenon is that the two populations of clusters have different spatial distributions. We test this idea by comparing clusters observed in unusually deep, high signal-to-noise images …
Spectroscopic evidence of charge exchange X-ray emission from galaxies
Wang, Q. D.; Liu, J.
What are the origins of the soft X-ray line emission from non-AGN galaxies? XMM-Newton RGS spectra of nearby non-AGN galaxies (including starforming ones: M82, NGC 253, M51, M83, M61, NGC 4631, M94, NGC 2903, and the Antennae galaxies, as well as the inner bulge of M31) have been analyzed. In particular, the K\alpha triplet of O VII shows that the…
Identifying Type IIn supernova progenitors in our Galaxy: the circumstellar environment of the Galactic luminous blue variable candidate Gal 026.47+0.02
Paladini, R.; Umana, G.; Agliozzo, C. +7 more
New data from the Herschel Infrared Galactic Plane Survey (Hi-GAL) and the Expanded Very Large Array, together with ancillary multifrequency data from different archives, have provided a comprehensive picture of the circumstellar envelope (CSE) surrounding the Galactic luminous blue variable (LBV) candidate Gal 026.47+0.02. The high angular resolu…
Old Massive Globular Clusters and the Stellar Halo of the Dwarf Starburst Galaxy NGC 4449
Caldwell, Nelson; Strader, Jay; Seth, Anil C.
We use Hubble Space Telescope imaging to show that the nearby dwarf starburst galaxy NGC 4449 has an unusual abundance of luminous red star clusters. Joint constraints from integrated photometry, low-resolution spectroscopy, dynamical mass-to-light ratios, and resolved color-magnitude diagrams provide evidence that some of these clusters are old g…
Lambert albedo retrieval and analyses over Aram Chaos from OMEGA hyperspectral imaging data
Liu, Yang; Arvidson, Raymond E.; Wolff, Michael J. +4 more
The DISORT radiative transfer model was used to retrieve Lambert albedos from 0.4 to 4.0 µm over hydrated sulfate deposits in Aram Chaos for the Mars Express OMEGA instrument. Albedos were also retrieved for a relatively anhydrous area to the north to use as a control for comparison to the hydrated sulfate spectra. Atmospheric gases and aero…
A Nearby Analog of z ~ 2 Compact Quiescent Galaxies with a Rotating Disk
Franx, Marijn; van Dokkum, Pieter; Bezanson, Rachel +1 more
Recent studies have identified a population of compact quiescent galaxies at z ~ 2. These galaxies are very rare today and establishing the existence of a nearby analog could allow us to study its structure in greater detail than is possible at high redshift. Here we present such a local analog, NGC 5845, which has a dynamical mass of M dyn
On the problem of Plasma Sheet Boundary Layer identification from plasma moments in Earth's magnetotail
Sauvaud, J. -A.; Grigorenko, E. E.; Koleva, R.
The problem of identification of the interface region between the lobe and the Plasma Sheet (PS) - the Plasma Sheet Boundary Layer (PSBL) - using ion moments and magnetic field data often arises in works devoted to statistical studies of various PSBL phenomena. Our experience in the identification of this region based on the analysis of ion veloci…