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Feedback and Brightest Cluster Galaxy Formation: ACS Observations of the Radio Galaxy TN J1338-1942 at z = 4.1
Ford, H. C.; Demarco, R.; Infante, L. +43 more
We present deep optical imaging of the z=4.1 radio galaxy TN J1338-1942, obtained using the Advanced Camera for Surveys (ACS) on board the Hubble Space Telescope, as well as ground-based near-infrared imaging data from the European Southern Observatory (ESO) Very Large Telescope (VLT). The radio galaxy is known to reside within a large galaxy over…
A Spectroscopic Analysis of Blue Stragglers, Horizontal Branch Stars, and Turnoff Stars in Four Globular Clusters
Saffer, Rex A.; De Marco, Orsola; Shara, Michael M. +4 more
We present a spectroscopic analysis of HST STIS and FOS low- and intermediate-resolution spectroscopy of 55 stars in four globular clusters (47 Tucanae, M3, NGC 6752, and NGC 6397). Stars hotter than Teff=5750 K and with a signal-to-noise ratio larger than 15 were analyzed with non-local thermodynamic equilibrium model atmospheres, and …
X-Ray Emission from Orion Nebula Cluster Stars with Circumstellar Disks and Jets
Bally, John; Feigelson, Eric D.; Kastner, Joel H. +5 more
We investigate the X-ray and near-infrared emission properties of a sample of pre-main-sequence (PMS) stellar systems in the Orion Nebula Cluster (ONC) that display evidence for circumstellar disks (``proplyds'') and optical jets in Hubble Space Telescope (HST) imaging. Our study uses X-ray data acquired during Chandra Orion Ultradeep Program (COU…
Initial results of high-latitude magnetopause and low-latitude flank flux transfer events from 3 years of Cluster observations
Russell, C. T.; Zhang, H.; Zong, Q. -G. +9 more
We present initial results from a statistical study of Cluster multispacecraft flux transfer event (FTE) observations at the high-latitude magnetopause and low-latitude flanks from February 2001 to June 2003. Cluster FTEs are observed at both the high-latitude magnetopause and low-latitude flanks for both southward and northward IMF. Among the 122…
A deep survey of brown dwarfs in Orion with Gemini
Tamura, M.; Lucas, P. W.; Roche, P. F.
We report the results of a deep near-infrared (JHK) survey of the outer parts of the Trapezium Cluster with Gemini South/Flamingos. 396 sources were detected in a 26 arcmin2 area, including 138 brown dwarf candidates, defined as M < 0.075 Msolar for an assumed age of 1 Myr. Only 33 of the brown dwarf candidates are planeta…
Self-regulated active galactic nuclei heating in elliptical galaxies
Kawata, D.; Gibson, B. K.
We study the effect of active galactic nuclei (AGN) heating on the chemodynamical evolution of elliptical galaxies and their X-ray and optical properties using high-resolution Λ-dominated cold dark matter cosmological simulations. Our model considers an AGN as being `active' when a convergent gas inflow condition exists within the nucleus of a gal…
Two Pulsar Wind Nebulae: Chandra/XMM-Newton Imaging of GeV J1417-6100
Ng, C. -Y.; Romani, Roger W.; Roberts, Mallory S. E.
We report on Chandra ACIS and XMM-Newton MOS/pn imaging observations of two pulsar wind nebulae (K3/PSR J1420-6048 and G313.3+0.1, the ``Rabbit'') associated with the Galactic unidentified γ-ray source GeV J1417-6100. With excellent ACIS imaging the very energetic pulsar PSR J1420-6048 is separated from its surrounding nebula. This nebula has surp…
Abundance of Elements beyond the Iron Group in Cool DO White Dwarfs
Kruk, J. W.; Chayer, P.; Dupuis, J. +1 more
We report the presence of elements beyond the iron group in the atmospheres of the cool DO white dwarfs HD 149499 B and HZ 21. Photospheric lines of germanium (Z=32), arsenic (33), selenium (34), tin (50), tellurium (52), iodine (53), and perhaps bromine (35) are observed in ultraviolet spectra of HD 149499 B obtained with the Far Ultraviolet Spec…
Signature of Saturn's auroral cusp: Simultaneous Hubble Space Telescope FUV observations and upstream solar wind monitoring
Cowley, Stanley W. H.; Bunce, Emma J.; Clarke, John T. +3 more
Model simulations by Bunce et al. (2005a) have shown that direct precipitation of electrons in Saturn's dayside cusp regions is not capable of producing significant FUV aurora. Instead, they suggested the possibility that the FUV bright emissions sometimes observed near noon are associated with reconnection occurring at the dayside magnetopause, p…
Where are the X-ray quasi-periodic oscillations in active galaxies?
Vaughan, S.; Uttley, P.
In this paper, we address the question of whether existing X-ray observations of Seyfert galaxies are sufficiently sensitive to detect quasi-periodic oscillations (QPOs) similar to those observed in the X-ray variations of Galactic black holes (GBHs). We use data from XMM-Newton and simulated data based on the best Rossi X-ray Timing Explorer (RXT…