Search Publications
A Bar Fuels a Supermassive Black Hole?: Host Galaxies of Narrow-Line Seyfert 1 Galaxies
Ohta, Kouji; Kawaguchi, Toshihiro; Aoki, Kentaro +1 more
We present optical images of nearby 50 narrow-line Seyfert 1 galaxies (NLS1s) that cover all the NLS1s at z<0.0666 and δ>=-25deg known in 2001. Among the 50 NLS1s, 40 images are newly obtained by our observations and 10 images are taken from archive data. Motivated by the hypothesis that NLS1s are in an early phase of a supermassi…
The Cosmic Evolution Survey (COSMOS): A Large-Scale Structure at z=0.73 and the Relation of Galaxy Morphologies to Local Environment
Finoguenov, A.; Böhringer, H.; Kneib, J. -P. +29 more
We have identified a large-scale structure at z~=0.73 in the COSMOS field, coherently described by the distribution of galaxy photometric redshifts, an ACS weak-lensing convergence map, and the distribution of extended X-ray sources in a mosaic of XMM-Newton observations. The main peak seen in these maps corresponds to a rich cluster with TX<…
An X-Ray Census of Young Stars in the Massive Southern Star-forming Complex NGC 6357
Tsujimoto, Masahiro; Garmire, Gordon P.; Feigelson, Eric D. +4 more
We present the first high spatial resolution X-ray study of the massive star-forming region NGC 6357, obtained in a 38 ks Chandra/ACIS observation. Inside the brightest constituent of this large H II region complex is the massive open cluster Pismis 24. It contains two of the brightest and bluest stars known, yet remains poorly studied; only a han…
Simulating the Cosmos: The Fraction of Merging Galaxies at High Redshift
Taniguchi, Y.; Sargent, M. T.; Capak, P. +7 more
Simulations of nearby (0.015<z<0.025) SDSS galaxies have been used to reproduce as accurately as possible the appearance that they would have on COSMOS ACS images if they had been observed at z~0.7 and ~1.2. These simulations include surface brightness dimming, the effects of bandpass shifting, the changing spatial resolution, and the increa…
The XMM-Newton Wide-Field Survey in the COSMOS Field. V. Angular Clustering of the X-Ray Point Sources
Comastri, Andrea; Zamorani, Giovanni; Fiore, Fabrizio +9 more
We present the first results of the measurements of angular auto-correlation functions (ACFs) of X-ray point sources detected in the XMM-Newton observations of the ~2 deg2 COSMOS field (COSMOS XMM-Newton). Significant positive signals have been detected in the 0.5-2 (SFT) band, in the angle range of 0.5'-24', while the positive signals …
Astrometric Orbits for Hipparcos Stochastic Binaries
Makarov, V. V.; Goldin, A.
Taking advantage of an improved genetic optimization algorithm for fitting unconstrained Kepler orbits to the Hipparcos intermediate astrometric data, we obtain additional orbital solutions for 81 Hipparcos stars with previous stochastic (failed) solutions. The sample includes astrophysically interesting objects, including the old disk wide binary…
The Angular Correlations of Galaxies in the COSMOS Field
Finoguenov, A.; Aussel, H.; Sanders, D. B. +21 more
We present measurements of the two-point galaxy angular correlation function w(θ) in the COSMOS field. Independent determinations of w(θ) as a function of magnitude limit are presented for both the Hubble Space Telescope (HST) ACS catalog and also the ground-based data from Subaru and the Canada-France-Hawaii Telescope. Despite having significantl…
The Abundances of Light Neutron-Capture Elements in Planetary Nebulae. I. Photoionization Modeling and Ionization Corrections
Kallman, T. R.; Dinerstein, Harriet L.; Sterling, N. C.
We have conducted a large-scale survey of 120 planetary nebulae (PNe) to search for the near-infrared emission lines [Kr III] 2.199 µm and [Se IV] 2.287 µm. The neutron (n)-capture elements Se and Kr may be enriched in a PN if its progenitor star experienced s-process nucleosynthesis and third dredge-up. In order to determine Se and Kr…
Virial Masses of Black Holes from Single Epoch Spectra of Active Galactic Nuclei
Bechtold, Jill; Kelly, Brandon C.
We describe the general problem of estimating black hole masses of active galactic nuclei (AGNs) by calculating the conditional probability distribution of MBH given some set of observables. Special attention is given to the case where one uses the AGN continuum luminosity and emission line widths to estimate MBH, and we outl…
A Wide-Angle Tail Radio Galaxy in the COSMOS Field: Evidence for Cluster Formation
Finoguenov, A.; Kartaltepe, J. S.; Murayama, T. +19 more
We have identified a complex galaxy cluster system in the COSMOS field via a wide-angle tail (WAT) radio galaxy, consistent with the idea that WAT galaxies can be used as tracers of clusters. The WAT galaxy, CWAT-01, is coincident with an elliptical galaxy resolved in the HST ACS image. Using the COSMOS multiwavelength data set, we derive the radi…