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A close look at the Centaurus A group of galaxies. IV. Recent star formation histories of late-type dwarfs around CenA
Crnojević, D.; Grebel, E. K.; Cole, A. A.
Aims: We study a sample of five dwarf irregular galaxies in the CenA/M 83 group, which are companions to the giant elliptical CenA. We aim at deriving their physical properties over their lifetime and compare them to those of dwarfs located in different environments.
Methods: We use archival HST/ACS data and apply synthetic color-magnitu…
Analytical shear and flexion of Einasto dark matter haloes
Baes, M.; Frutos-Alfaro, F.; Retana-Montenegro, E.
N-body simulations predict that dark matter haloes are described by specific density profiles on both galactic- and cluster-sized scales. Weak gravitational lensing through the measurements of their first and second order properties, shear and flexion, is a powerful observational tool for investigating the true shape of these profiles. One of the …
Regolith grain sizes of Saturn’s rings inferred from Cassini-CIRS far-infrared spectra
Spilker, Linda; Morishima, Ryuji; Edgington, Scott G.
We analyze far-infrared (10-650 cm-1) emissivity spectra of Saturn’s main rings obtained by the Cassini Composite Infrared Spectrometer (CIRS). In modeling of the spectra, the single scattering albedos of regolith grains are calculated using the Mie theory, diffraction is removed with the delta-Eddington approximation, and the hemispher…
A planetary companion around the K giant ɛ Corona Borealis
Lee, B. -C.; Park, M. -G.; Han, I. +2 more
Aims: Our aim is to search for and study the origin of the low-amplitude and long-periodic radial velocity (RV) variations in K giants.
Methods: We present high-resolution RV measurements of K2 giant ɛ CrB from February 2005 to January 2012 using the fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) at the Bohyunsan Optical Ast…
The Merger History, Active Galactic Nucleus, and Dwarf Galaxies of Hickson Compact Group 59
Hornschemeier, A. E.; Brandt, W. N.; Konstantopoulos, I. S. +16 more
Compact group galaxies often appear unaffected by their unusually dense environment. Closer examination can, however, reveal the subtle, cumulative effects of multiple galaxy interactions. Hickson Compact Group (HCG) 59 is an excellent example of this situation. We present a photometric study of this group in the optical (Hubble Space Telescope), …
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…