Search Publications
Observations of Plasma Upflow in a Warm Loop with Hinode/EIS
Del Zanna, Giulio; Tripathi, Durgesh; Mason, Helen E. +1 more
A complete understanding of Doppler shift in active region loops can help probe the basic physical mechanism involved into the heating of those loops. Here, we present observations of upflows in coronal loops detected in a range of temperatures (log T = 5.8-6.2). The loop was not discernible above these temperatures. The speed of upflow was strong…
Interstellar Silicate Dust in the z = 0.89 Absorber toward PKS 1830-211: Crystalline Silicates at High Redshift?
York, Donald G.; Kulkarni, Varsha P.; Welty, Daniel E. +3 more
We present evidence of a >10σ detection of the 10 µm silicate dust absorption feature in the spectrum of the gravitationally lensed quasar PKS 1830-211, produced by a foreground absorption system at redshift 0.886. We have examined more than 100 optical depth templates, derived from both observations of Galactic and extragalactic sources …
GALEX-selected Lyman Break Galaxies at z ~ 2: Comparison with Other Populations
Nesvadba, N.; Haberzettl, L.; Lehnert, M. D. +2 more
We present results of a search for bright Lyman break galaxies (LBGs) at 1.5 <= z <= 2.5 in the GOODS-S field using an NUV-dropout technique in combination with color selection. We derived a sample of 73 LBG candidates. We compare our selection efficiencies to BM/BX and BzK methods (techniques solely based on ground-based data sets), and fin…
CO and H2 Absorption in the AA Tauri Circumstellar Disk
Herczeg, Gregory J.; Brown, Alexander; France, Kevin +7 more
The direct study of molecular gas in inner protoplanetary disks is complicated by uncertainties in the spatial distribution of the gas, the time variability of the source, and the comparison of observations across a wide range of wavelengths. Some of these challenges can be mitigated with far-ultraviolet spectroscopy. Using new observations obtain…
X-Ray Binaries and Star Clusters in the Antennae: Optical Cluster Counterparts
Whitmore, Bradley C.; Chandar, Rupali; Rangelov, Blagoy +1 more
We compare the locations of 82 X-ray binaries (XRBs) detected in the merging Antennae galaxies by Zezas et al., based on observations taken with the Chandra X-Ray Observatory, with a catalog of optically selected star clusters presented by Whitmore et al., based on observations taken with the Hubble Space Telescope. Within the 2σ positional uncert…
The Panchromatic Hubble Andromeda Treasury. III. Measuring Ages and Masses of Partially Resolved Stellar Clusters
Bell, Eric F.; Gouliermis, Dimitrios A.; Dolphin, Andrew E. +14 more
The apparent age and mass of a stellar cluster can be strongly affected by stochastic sampling of the stellar initial mass function (IMF), when inferred from the integrated color of low-mass clusters (lsim104 M ⊙). We use simulated star clusters to show that these effects are minimized when the brightest, rapidly evolving sta…
The Chandra Local Volume Survey: The X-Ray Point-source Catalog of NGC 300
Dalcanton, J. J.; Skillman, E. D.; Kong, A. K. H. +7 more
We present the source catalog of a new Chandra ACIS-I observation of NGC 300 obtained as part of the Chandra Local Volume Survey. Our 63 ks exposure covers ~88% of the D 25 isophote (R ≈ 6.3 kpc) and yields a catalog of 95 X-ray point sources detected at high significance to a limiting unabsorbed 0.35-8 keV luminosity of ~1036
[Fe III] Emission Lines in the Planetary Nebula NGC 2392
Zhang, Y.; Liu, X. -W.; Koning, N. +4 more
NGC 2392 is a young double-shell planetary nebula (PN). Its intrinsic structure and shaping mechanism are still not fully understood. In this paper we present new spectroscopic observations of NGC 2392. The slits were placed at two different locations to obtain the spectra of the inner and outer regions. Several [Fe III] lines are clearly detected…
A Variable Ultraluminous X-Ray Source in a Globular Cluster in NGC 4649
Zezas, A.; Luo, B.; Gallagher, J. S. +9 more
We report the discovery of a new ultraluminous X-ray source associated with a globular cluster in the elliptical galaxy NGC 4649. The X-ray source was initially detected with a luminosity below 5 × 1038 erg s-1, but in subsequent observations 7 and 11 years later it had brightened substantially to 2-3 × 1039 erg s<…
Solar Radio Type-I Noise Storm Modulated by Coronal Mass Ejections
Misawa, H.; Shiota, D.; Inoue, S. +6 more
The first coordinated observations of an active region using ground-based radio telescopes and the Solar Terrestrial Relations Observatory (STEREO) satellites from different heliocentric longitudes were performed to study solar radio type-I noise storms. A type-I noise storm was observed between 100 and 300 MHz during a period from 2010 February 6…