Search Publications
Mid-Infrared Spectroscopy of Carbon Stars in the Small Magellanic Cloud
Price, S. D.; Wood, P. R.; Matsuura, M. +3 more
We have observed a sample of 36 objects in the Small Magellanic Cloud (SMC) with the Infrared Spectrometer on the Spitzer Space Telescope. Nineteen of these sources are carbon stars. An examination of the near- and mid-infrared photometry shows that the carbon-rich and oxygen-rich dust sources follow two easily separated sequences. A comparison of…
Determining Solar Abundances Using Helioseismology
Basu, Sarbani; Antia, H. M.
The recent downward revision of solar photospheric abundances of oxygen and other heavy elements has resulted in serious discrepancies between solar models and solar structure as determined through helioseismology. In this work we investigate the possibility of determining the solar heavy-element abundance without reference to spectroscopy by usin…
Fe K Emission and Absorption in the XMM-EPIC Spectrum of the Seyfert Galaxy IC 4329a
Reeves, J. N.; Braito, V.; Markowitz, A.
We present a detailed analysis of the XMM-Newton long-look of the Seyfert galaxy IC 4329a. The Fe K bandpass is dominated by two resolved peaks at 6.4 and 7.0 keV, consistent with neutral or near-neutral Fe Kα and Kβ emission. There is a prominent redward asymmetry in the 6.4 keV line, which could indicate emission from a Compton shoulder. Alterna…
Linking Stellar Mass and Star Formation in Spitzer MIPS 24 µm Galaxies
Le Floc'h, E.; Dole, H.; Lagache, G. +7 more
We present deep Ks<21.5 (Vega) identifications, redshifts, and stellar masses for most of the sources composing the bulk of the 24 µm background in the GOODS/CDFS. Our identified sample consists of 747 Spitzer MIPS 24 µm objects and includes ~94% of all the 24 µm sources in the GOODS-South field that have fluxes S
An HST Study of the Supernovae Accompanying GRB 040924 and GRB 041006
Cenko, S. B.; Peterson, B. A.; Price, P. A. +23 more
We present the results from a Hubble Space Telescope ACS study of the supernovae (SNe) associated with gamma-ray bursts (GRBs) 040924 (z=0.86) and 041006 (z=0.71). We find evidence that both GRBs were associated with an SN 1998bw-like supernova dimmed by ~1.5 and ~0.3 mag, respectively, making GRB 040924 the faintest GRB-associated SN ever detecte…
Meridional Circulation Variability from Large-Aperture Ring-Diagram Analysis of Global Oscillation Network Group and Michelson Doppler Imager Data
Howe, R.; Komm, R.; Hill, F. +3 more
Ring-diagram analysis, a local helioseismology technique, has proven to be very useful for studying solar subsurface velocity flows down to a depth of about 0.97 Rsolar. The depth range is determined by the modes used in this type of analysis, and thus depends on the size of the area analyzed. Extending the area allows us to detect lowe…
Neon and Oxygen Abundances in M33
Massey, Philip; Garnett, Donald R.; Jacoby, George +1 more
We present new spectroscopic observations of 13 H II regions in the Local Group spiral galaxy M33. The regions observed range from 1 to 7 kpc in distance from the nucleus. Of the 13 H II regions observed, the [O III] λ4363 line was detected in six regions. Electron temperatures were thus able to be determined directly from the spectra using the [O…
Outflows from Massive Young Stellar Objects as Seen with the Infrared Array Camera
Smith, Howard A.; Marengo, M.; Hora, J. L. +1 more
The bipolar outflow from the massive star-forming cluster in DR 21 is one of the most powerful known, and in IRAC images the outflow stands out by virtue of its brightness at 4.5 µm (band 2). Indeed, IRAC images of many Galactic and extragalactic star formation regions feature prominent band 2 morphologies. We have analyzed archival ISO SWS …
An Overdensity of Galaxies near the Most Distant Radio-loud Quasar
Ford, H. C.; Demarco, R.; Infante, L. +41 more
A 5 arcmin2 region around the luminous radio-loud quasar SDSS J0836+0054 (z=5.8) hosts a wealth of associated galaxies, characterized by very red (1.3<i775-z850<2.0) color. The surface density of these z~5.8 candidates is approximately 6 times higher than the number expected from deep ACS fields. This is one …
Magnetic Causes of Solar Coronal Mass Ejections: Dominance of the Free Magnetic Energy over the Magnetic Twist Alone
Falconer, D. A.; Moore, R. L.; Gary, G. A.
We examine the magnetic causes of coronal mass ejections (CMEs) by examining, along with the correlations of active-region magnetic measures with each other, the correlations of these measures with active-region CME productivity observed in time windows of a few days, either centered on or extending forward from the day of the magnetic measurement…