Search Publications
Probing the GC-LMXB Connection in NGC 1399: A Wide-field Study with the Hubble Space Telescope and Chandra
Kundu, Arunav; Zepf, Stephen E.; Maccarone, Thomas J. +5 more
We present a wide-field study of the globular cluster (GC)/low-mass X-ray binary (LMXB) connection in the giant elliptical NGC 1399. The large field of view of the Advanced Camera for Surveys/WFC, combined with Hubble Space Telescope and Chandra high resolution, allow us to constrain the LMXB formation scenarios in elliptical galaxies. We confirm …
Nonlinear Color-Metallicity Relations of Globular Clusters. III. On the Discrepancy in Metallicity between Globular Cluster Systems and Their Parent Elliptical Galaxies
Peng, Eric W.; Blakeslee, John P.; Sohn, Sangmo T. +7 more
One of the conundrums in extragalactic astronomy is the discrepancy in observed metallicity distribution functions (MDFs) between the two prime stellar components of early-type galaxies—globular clusters (GCs) and halo field stars. This is generally taken as evidence of highly decoupled evolutionary histories between GC systems and their parent ga…
The Photometric and Spectral Evolution of the 2008 Luminous Optical Transient in NGC 300
Walter, Frederick M.; Bond, Howard E.; Humphreys, Roberta M. +5 more
The 2008 optical transient in NGC 300 is one of a growing class of intermediate-luminosity transients that brighten several orders of magnitude from a previously optically obscured state. The origin of their eruptions is not understood. Our multi-wavelength photometry and spectroscopy from maximum light to more than a year later provide a record o…
Four IRAC Sources with an Extremely Red H - [3.6] Color: Passive or Dusty Galaxies at z > 4.5?
Wang, T.; Rigopoulou, D.; Fazio, G. G. +3 more
We report the detection of four IRAC sources in the GOODS-South field with an extremely red color of H - [3.6] > 4.5. The four sources are not detected in the deep Hubble Space Telescope WFC3 H-band image with H limit = 28.3 mag. We find that only three types of SED templates can produce such a red H - [3.6] color: a very dusty SED w…
A Powerful AGN Outburst in RBS 797
McNamara, B. R.; Nulsen, P. E. J.; Gitti, M. +4 more
Utilizing ~50 ks of Chandra X-Ray Observatory imaging, we present an analysis of the intracluster medium (ICM) and cavity system in the galaxy cluster RBS 797. In addition to the two previously known cavities in the cluster core, the new and deeper X-ray image has revealed additional structure associated with the active galactic nucleus (AGN). The…
X-ray Emission from the Sombrero Galaxy: A Galactic-scale Outflow
Spitler, Lee R.; Jones, Christine; Gilfanov, Marat +8 more
Based on new and archival Chandra observations of the Sombrero galaxy (M 104 = NGC 4594), we study the X-ray emission from its nucleus and the extended X-ray emission in and around its massive stellar bulge. We find that the 0.3-8 keV luminosity of the nucleus appears constant at ~2.4 × 1040 erg s-1, or ~10-7 of it…
X-Ray Characteristics of NGC 3516: A View through the Complex Absorber
Turner, T. J.; Kraemer, S. B.; Reeves, J. N. +1 more
We consider new Suzaku data for NGC 3516 taken during 2009 along with other recent X-ray observations of the source. The cumulative characteristics of NGC 3516 cannot be explained without invoking changes in the line-of-sight absorption. Contrary to many other well-studied Seyfert galaxies, NGC 3516 does not show a positive lag of hard X-ray photo…
Temporal Variability of Active Region Outflows
Warren, Harry P.; Ugarte-Urra, Ignacio
Recent observations from the Extreme-ultraviolet Imaging Spectrometer (EIS) on board Hinode have shown that low-density areas on the periphery of active regions are characterized by strong blueshifts in the emission of spectral lines formed at 1 MK. These Doppler shifts have been associated with outward propagating disturbances observed with extre…
The Formation of Kiloparsec-scale H I Holes in Dwarf Galaxies
Van Dyk, Schuyler D.; Cannon, John M.; Dolphin, Andrew E. +10 more
The origin of kpc-scale holes in the atomic hydrogen (H I) distributions of some nearby dwarf irregular galaxies presents an intriguing problem. Star formation histories (SFHs) derived from resolved stars give us the unique opportunity to study past star-forming events that may have helped shape the currently visible H I distribution. Our sample o…
A Microlensing Measurement of Dark Matter Fractions in Three Lensing Galaxies
Wyithe, J. S. B.; Bate, N. F.; Floyd, D. J. E. +1 more
Direct measurements of dark matter distributions in galaxies are currently only possible through the use of gravitational lensing observations. Combinations of lens modeling and stellar velocity dispersion measurements provide the best constraints on dark matter distributions in individual galaxies, however they can be quite complex. In this paper…