Search Publications
Population of SOHO/STEREO Kreutz Sungrazers and the Arrival of Comet C/2011 W3 (Lovejoy)
Sekanina, Zdenek; Kracht, Rainer
We examine properties of the population of SOHO/STEREO (dwarf) Kreutz sungrazing comets from 2004 to 2013, including the arrival rates, peculiar gaps, and a potential relationship to the spectacular comet C/2011 W3 (Lovejoy). Selection effects, influencing the observed distribution, are largely absent among bright dwarf sungrazers, whose temporal …
Turbulence in the SuperModel: Mass Reconstruction with Nonthermal Pressure for A1835
Lapi, A.; Fusco-Femiano, R.
The total mass derived from X-ray emission is biased low in a large number of clusters when compared with the mass estimated via strong and weak lensing. Suzaku and Chandra observations out to the virial radius report in several relaxed clusters' steep temperature gradients that on assuming pure thermal hydrostatic equilibrium (HE) imply an unphys…
Probing of the Interactions between the Hot Plasmas and Galaxies in Clusters from z = 0.1 to 0.9
Shimasaku, Kazuhiro; Gandhi, Poshak; Makishima, Kazuo +7 more
Based on optical and X-ray data for a sample of 34 relaxed rich clusters of galaxies with redshifts of 0.1-0.9, we studied relative spatial distributions of the two major baryon contents, the cluster galaxies and the hot plasmas. Using multi-band photometric data taken with the UH88 telescope, we determined the integrated (two-dimensional) radial …
Nonlinear Color-Metallicity Relations of Globular Clusters. IV. Testing the Nonlinearity Scenario for Color Bimodality via HST/WFC3 u-band Photometry of M84 (NGC 4374)
Blakeslee, John P.; Sohn, Sangmo T.; Kim, Hak-Sub +4 more
Color distributions of globular clusters (GCs) in most massive galaxies are bimodal. Assuming linear color-to-metallicity conversions, bimodality is viewed as the presence of merely two GC subsystems with distinct metallicities, which serves as a critical backbone of various galaxy formation theories. Recent studies, however, revealed that the col…
A Good Mass Proxy for Galaxy Clusters with XMM-Newton
Zhao, Hai-Hui; Xie, Fei; Jia, Shu-Mei +3 more
We use a sample of 39 galaxy clusters at redshift z < 0.1 observed by XMM-Newton to investigate the relations between X-ray observables and total mass. Based on central cooling time and central temperature drop, the clusters in this sample are divided into two groups: 25 cool core clusters and 14 non-cool core clusters, respectively. We study t…
Comparison of Force-free Coronal Magnetic Field Modeling Using Vector Fields from Hinode and Solar Dynamics Observatory
Wiegelmann, T.; Thalmann, J. K.; Tiwari, S. K.
Photospheric magnetic vector maps from two different instruments are used to model the nonlinear force-free coronal magnetic field above an active region. We use vector maps inferred from polarization measurements of the Solar Dynamics Observatory/Helioseismic and Magnetic Imager (HMI) and the Solar Optical Telescope's Spectropolarimeter (SP) on b…
Collimation and Scattering of the Active Galactic Nucleus Emission in the Sombrero Galaxy
Ricci, T. V.; Steiner, J. E.; Menezes, R. B.
We present an analysis of a data cube of the central region of M104, the Sombrero galaxy, obtained with the GMOS-IFU of the Gemini-South telescope, and report the discovery of collimation and scattering of the active galactic nucleus (AGN) emission in the circumnuclear region of this galaxy. Analysis with PCA Tomography and spectral synthesis reve…
On the Hubble Space Telescope Trigonometric Parallax of the Dwarf Nova SS Cygni
Nelan, Edmund P.; Bond, Howard E.
SS Cygni is one of the brightest dwarf novae (DNe), and one of the best studied prototypes of the cataclysmic variables. Astrometric observations with the Fine Guidance Sensors (FGSs) on the Hubble Space Telescope (HST), published in 2004, gave an absolute trigonometric parallax of 6.06 ± 0.44 mas. However, recent very long baseline interferometry…
Interstellar Dust Properties of M51 from AKARI Mid-infrared Images
Onaka, Takashi; Arimatsu, Ko; Matsuhara, Hideo +3 more
Using mid-infrared (MIR) images of four photometric bands of the Infrared Camera on board the AKARI satellite, S7 (7 µm), S11 (11 µm), L15 (15 µm), and L24 (24 µm), we investigate the interstellar dust properties of the nearby pair of galaxies M51 with respect to their spiral arm structure. The arm and interarm regions are …
WMAP Observations of Planck ESZ Clusters
Hinshaw, Gary; Scott, Douglas; Ma, Yin-Zhe
We examine the Sunyaev-Zeldovich (SZ) effect in the seven year Wilkinson Microwave Anisotropy Probe (WMAP) data by cross-correlating it with the Planck Early-release Sunyaev-Zeldovich catalog. Our analysis proceeds in two parts. We first perform a stacking analysis in which the filtered WMAP data are averaged at the locations of the 175 Planck clu…