Search Publications
Discovery of X-ray emission from the protostellar jet L1551 IRS5 (HH 154)
Micela, G.; Favata, F.; Sciortino, S. +2 more
We have for the first time detected X-ray emission associated with a protostellar jet, on the jet emanating from the L1551 IRS5 protostar. The IRS5 protostar is hidden behind a very large absorbing column density, making the direct observation of the jet's emission possible. The observed X-ray emission is likely associated with the shock ``working…
GRB 011121: A Massive Star Progenitor
Wieringa, M. H.; Axelrod, T. S.; Frontera, F. +29 more
Of the cosmological gamma-ray bursts, GRB 011121 has the lowest redshift, z=0.36. More importantly, the multicolor excess in the afterglow detected in the Hubble Space Telescope (HST) light curves is compelling observational evidence of an underlying supernova. Here we present near-infrared and radio observations of the afterglow, and from our com…
Three LINERs under the Chandra X-Ray Microscope
Moran, Edward C.; Shields, Joseph C.; Eracleous, Michael +1 more
We use observations of three galaxies hosting low-ionization nuclear emission-line regions (LINERs; NGC 404, NGC 4736, and NGC 4579) with the Chandra X-Ray Observatory to study their power sources. We find very diverse properties within this small group: NGC 404 has an X-ray faint nucleus with a soft, thermal spectrum; NGC 4736 harbors a plethora …
Dust and the spectral energy distribution of the OH/IR star OH 127.8+0.0: Evidence for circumstellar metallic iron
Waters, L. B. F. M.; de Koter, A.; Tielens, A. G. G. M. +2 more
We present a fit to the spectral energy distribution of
Flare Activity and Magnetic Helicity Injection by Photospheric Horizontal Motions
Moon, Y. -J.; Wang, Haimin; Yurchyshyn, Vasyl +5 more
We present observational evidence that the occurrence of homologous flares in an active region is physically related to the injection of magnetic helicity by horizontal photospheric motions. We have analyzed a set of 1 minute cadence magnetograms of NOAA AR 8100 taken over a period of 6.5 hr by the Michelson Doppler Imager on board the Solar and H…
Saturn: Search for a missing water source
Johnson, R. E.; Jurac, S.; Richardson, J. D. +3 more
The origin of the large hydroxyl radical (OH) cloud near the inner moons of Saturn, indicative of a surprisingly large water-vapor source, has represented a puzzle since its discovery in 1992. A new set of Hubble Space Telescope measurements is used to constrain the OH spatial densities and to pinpoint the source region. Our model indicates that t…
Photospheric Motions and Coronal Mass Ejection Productivity
Zhang, H.; Nindos, A.
Shearing motions have been frequently used in MHD simulations of coronal mass ejection (CME) initiation but have hardly been reported from observations of CME-producing regions. In this Letter, we investigate whether the bulk of magnetic helicity carried away from the Sun by CMEs comes from helicity injected to the corona by such motions or by eme…
Nanodiamonds around HD 97048 and Elias 1
Tielens, A. G. G. M.; Waelkens, C.; Van Kerckhoven, C.
We present an analysis of ISO-SWS observations of the Herbig Ae/Be stars HD 97048 and Elias 1. Besides the well-known family of IR emission bands at 3.3, 6.2, ``7.7'', 8.6 and 11.2 mu m these objects show strong, peculiar emission features at 3.43 and 3.53 mu m. The latter two features show pronounced substructure which is very similar in the two …
Bow Shocks from Neutron Stars: Scaling Laws and Hubble Space Telescope Observations of the Guitar Nebula
Chatterjee, S.; Cordes, J. M.
The interaction of high-velocity neutron stars with the interstellar medium produces bow shock nebulae, in which the relativistic neutron star wind is confined by ram pressure. We present multiwavelength observations of the Guitar Nebula, including narrowband Hα imaging with Hubble Space Telescope (HST) WFPC2, which resolves the head of the bow sh…
Mid-Infrared Observation of Mass Loss in Elliptical Galaxies
Sauvage, Marc; Temi, Pasquale; Bregman, Jesse +2 more
Early-type galaxies exhibit thermal and molecular resonance emission from dust that is shed and heated through stellar mass loss as a subset of the population moves through the asymptotic giant branch (AGB) phase of evolution. Because this emission can give direct insight into stellar evolution in addition to galactic stellar mass loss and interst…