Search Publications
The W40 Region in the Gould Belt: An Embedded Cluster and H II Region at the Junction of Filaments
Bachiller, Rafael; Samal, M. R.; Ojha, D. K. +3 more
We present a multiwavelength study of the W40 star-forming region using infrared (IR) observations in the UKIRT JHK bands, Spitzer Infrared Array Camera bands, and Herschel PACS bands, 2.12 µm H2 narrowband imaging, and radio continuum observations from GMRT (610 and 1280 MHz), in a field of view (FoV) of ~34' × 40'. Archival Spit…
Time-dependent Modeling of Pulsar Wind Nebulae
Tibolla, O.; Ferreira, S. E. S.; Kaufmann, S. +1 more
A spatially independent model that calculates the time evolution of the electron spectrum in a spherically expanding pulsar wind nebula (PWN) is presented, allowing one to make broadband predictions for the PWN's non-thermal radiation. The source spectrum of electrons injected at the termination shock of the PWN is chosen to be a broken power law.…
An X-Ray Survey of the Young Stellar Population of the Lynds 1641 and Iota Orionis Regions
Walter, F.; Micela, G.; Megeath, S. T. +12 more
We present an XMM-Newton survey of the part of the Orion A cloud south of the Orion Nebula. This survey includes the Lynds 1641 (L1641) dark cloud, a region of the Orion A cloud with very few massive stars and hence a relatively low ambient UV flux, and the region around the O9 III star ι Orionis. In addition to proprietary data, we used archival …
X-Ray Outflows and Super-Eddington Accretion in the Ultraluminous X-Ray Source Holmberg IX X-1
Harrison, F. A.; Fabian, A. C.; Miller, J. M. +4 more
Studies of X-ray continuum emission and flux variability have not conclusively revealed the nature of ultraluminous X-ray sources (ULXs) at the high-luminosity end of the distribution (those with L X >= 1040 erg s-1). These are of particular interest because the luminosity requires either super-Eddington accreti…
Chandra, Keck, and VLA Observations of the Crab Nebula during the 2011-April Gamma-Ray Flare
Weisskopf, Martin C.; Tennant, Allyn F.; Fu, Hai +22 more
We present results from our analysis of Chandra X-Ray Observatory, W. M. Keck Observatory, and Karl G. Jansky Very Large Array (VLA) images of the Crab Nebula that were contemporaneous with the γ-ray flare of 2011 April. Despite hints in the X-ray data, we find no evidence for statistically significant variations that pinpoint the specific locatio…
A Survey of H2O, CO2, and CO Ice Features toward Background Stars and low-mass Young Stellar Objects Using AKARI
Pontoppidan, K. M.; Sakon, I.; Noble, J. A. +2 more
We present near-infrared spectroscopic observations of 19 molecular clouds made using the AKARI satellite, and the data reduction pipeline written to analyze those observations. The 2.5-5 µm spectra of 30 objects—22 field stars behind quiescent molecular clouds and 8 low-mass young stellar objects in cores—were successfully extracted using t…
Study on the Triggering Process of Solar Flares Based on Hinode/SOT Observations
Kusano, K.; Yamamoto, T. T.; Okamoto, T. J. +1 more
We investigated four major solar flare events that occurred in active regions NOAA 10930 (2006 December 13 and 14) and NOAA 11158 (2011 February 13 and 15) by using data observed by the Solar Optical Telescope on board the Hinode satellite. To reveal the trigger mechanism of solar flares, we analyzed the spatio-temporal correlation between the det…
Deuterated Molecules in Orion KL from Herschel/HIFI
Bergin, Edwin A.; Neill, Justin L.; Crockett, Nathan R. +2 more
We present a comprehensive study of the deuterated molecules detected in the fullband HIFI survey of the Orion Kleinmann-Low nebula (Orion KL) region. Ammonia, formaldehyde, and methanol and their singly deuterated isotopologues are each detected through numerous transitions in this survey with a wide range in optical depths and excitation conditi…
The Far-infrared, UV, and Molecular Gas Relation in Galaxies up to z = 2.5
Berta, S.; Magnelli, B.; Nordon, R. +10 more
We use the infrared excess (IRX) FIR/UV luminosity ratio to study the relation between the effective UV attenuation (A IRX) and the UV spectral slope (β) in a sample of 450 1 < z < 2.5 galaxies. The FIR data are from very deep Herschel observations in the GOODS fields that allow us to detect galaxies with star formation rates (SFR…
Parallaxes and Proper Motions of Ultracool Brown Dwarfs of Spectral Types Y and Late T
Cushing, Michael C.; Kirkpatrick, J. Davy; Gelino, Christopher R. +5 more
We present astrometric measurements of 11 nearby ultracool brown dwarfs of spectral types Y and late-T, based on imaging observations from a variety of space-based and ground-based telescopes. These measurements have been used to estimate relative parallaxes and proper motions via maximum likelihood fitting of geometric model curves. To compensate…