Search Publications
Evaluating the Performance of Solar Flare Forecasting Methods
Leka, K. D.; Barnes, G.
The number of published approaches to solar flare forecasting using photospheric magnetic field observations has proliferated recently, with widely varying claims about how well each works. As different analysis techniques and data sets were used, it is essentially impossible to directly compare the results. A systematic comparison is presented he…
PAH Emission from Herbig Ae/Be Stars
Watson, D. M.; Chen, C. H.; Sargent, B. +10 more
We present spectra of a sample of Herbig Ae and Be (HAeBe) stars obtained with the Infrared Spectrograph on Spitzer. All but one of the Herbig stars show emission from PAHs, and seven of the spectra show PAH emission, but no silicate emission at 10 µm. The central wavelengths of the 6.2, 7.7-8.2, and 11.3 µm emission features decrease …
Discovery of the Radio and X-Ray Counterpart of TeV γ-Ray Source HESS J1731-347
Leahy, D. A.; Jiang, B.; Haverkorn, M. +1 more
We discover a faint shell-type radio and X-ray source, G353.6-0.7, associated with HESS J1731-347. G353.6-0.7 is likely an old supernova remnant (SNR), based on radio (0.8, 1.4, and 5 GHz), infrared (8 µm from the GLIMPSE Legacy Project and 21 µm from the Midcourse Space Experiment), and X-ray (0.1-2.4 keV from the ROSAT survey and 5-2…
Mid-Infrared Spectroscopy of Lensed Galaxies at 1 < z < 3: The Nature of Sources Near the MIPS Confusion Limit
Kneib, J. -P.; Rigby, J. R.; Papovich, C. +10 more
We present Spitzer IRS mid-infrared spectra for 15 gravitationally lensed, 24 µm-selected galaxies, and combine the results with four additional very faint galaxies with IRS spectra in the literature. The median intrinsic 24 µm flux density of the sample is 130 µJy, enabling a systematic survey of the spectral properties of the v…
Another Nonsegregated Blue Straggler Population in a Globular Cluster: the Case of NGC 2419
Dalessandro, E.; Bellazzini, M.; Ferraro, F. R. +3 more
We have used a combination of ACS HST high-resolution and wide-field Subaru data in order to study the blue straggler star (BSS) population over the entire extension of the remote Galactic globular cluster NGC 2419. The BSS population presented here is among the largest ever observed in any stellar system, with more than 230 BSSs in the brightest …
Spitzer Mid-Infrared Spectroscopy of Infrared Luminous Galaxies at z ~ 2. III. Far-IR to Radio Properties and Optical Spectral Diagnostics
Choi, Philip; Helou, George; Lutz, Dieter +7 more
We present the FIR, millimeter, and radio photometry and optical and NIR spectroscopy of a sample of 48 z ~ 1-3 Spitzer-selected ULIRGs with IRS MIR spectra. Our goals are to compute their bolometric emission and to determine both the presence and relative strength of their AGN and starburst components. We find that strong-PAH sources tend to have…
Dark Matter and Baryons in the X-Ray Luminous Merging Galaxy Cluster RX J1347.5-1145
Treu, Tommaso; Bradač, Maruša; Schrabback, Tim +12 more
The galaxy cluster RX J1347.5-1145 is one of the most X-ray luminous and most massive clusters known. This makes it a prime target for studying issues addressing cluster formation and cosmology. Despite the naive expectation that mass estimation for this cluster should be straightforward (high mass and favorable redshift make it an efficient lens;…
A Comprehensive View of the 2006 December 13 CME: From the Sun to Interplanetary Space
Liu, Y.; Sauvaud, J. -A.; Luhmann, J. G. +7 more
The biggest halo coronal mass ejection (CME) since the Halloween storm in 2003, which occurred on 2006 December 13, is studied in terms of its solar source and heliospheric consequences. The CME was accompanied by an X3.4 flare, EUV dimmings, and coronal waves. It generated significant space weather effects such as an interplanetary shock, radio b…
A Giant Flare from a Soft Gamma Repeater in the Andromeda Galaxy (M31)
Hurley, K.; von Kienlin, A.; Frederiks, D. D. +6 more
The light curve, energy spectra, energetics, and IPN localization of an exceedingly intense, short-duration, hard-spectrum burst, GRB 070201, obtained from Konus-Wind, INTEGRAL (SPI-ACS), and MESSENGER data are presented. The total fluence of the burst and the peak flux are S = 2.00+ 0.10-0.26 × 10-5 erg cm-2<…
The Horizontal Internetwork Magnetic Field: Numerical Simulations in Comparison to Observations with Hinode
Rezaei, R.; Wedemeyer-Böhm, S.; Steiner, O. +1 more
Observations with the Hinode space observatory led to the discovery of predominantly horizontal magnetic fields in the photosphere of the quiet internetwork region. Here we investigate realistic numerical simulations of the surface layers of the Sun with respect to horizontal magnetic fields and compute the corresponding polarimetric response in t…