Search Publications
Jet Rotation Investigated in the Near-ultraviolet with the Hubble Space Telescope Imaging Spectrograph
Bacciotti, Francesca; Coffey, Deirdre; Eislöffel, Jochen +2 more
We present results of the second phase of our near-ultraviolet investigation into protostellar jet rotation using the Hubble Space Telescope Imaging Spectrograph. We obtain long-slit spectra at the base of five T Tauri jets to determine if there is a difference in radial velocity between the jet borders which may be interpreted as a rotation signa…
Prior Flaring as a Complement to Free Magnetic Energy for Forecasting Solar Eruptions
Moore, Ronald L.; Falconer, David A.; Barghouty, Abdulnasser F. +1 more
From a large database of (1) 40,000 SOHO/MDI line-of-sight magnetograms covering the passage of 1300 sunspot active regions across the 30° radius central disk of the Sun, (2) a proxy of each active region's free magnetic energy measured from each of the active region's central-disk-passage magnetograms, and (3) each active region's full-disk-passa…
Rebirth of X-Ray Emission from the Born-again Planetary Nebula A30
Steffen, M.; Gruendl, R. A.; Hamann, W. -R. +8 more
The planetary nebula A30 is believed to have undergone a very late thermal pulse resulting in the ejection of knots of hydrogen-poor material. Using multi-epoch Hubble Space Telescope images, we have detected the angular expansion of these knots and derived an age of 850+280 - 150 yr. To investigate the spectral and spatial p…
The Cold Shoulder: Emission Measure Distributions of Active Region Cores
Schmelz, J. T.; Pathak, S.
The coronal heating mechanism for active region core loops is difficult to determine because these loops are often not resolved and cannot be studied individually. Rather, we concentrate on the "inter-moss" areas between loop footpoints. We use observations from the Hinode EUV Imaging Spectrometer and the X-Ray Telescope to calculate the emission …
Superorbital Modulation of X-Ray Emission from Gamma-Ray Binary LSI +61 303
Lutovinov, A.; Molkov, S.; Chernyakova, M. +3 more
We report the discovery of a systematic constant time lag between the X-ray and radio flares of the gamma-ray binary LSI +61 303, persistent over a long, multi-year timescale. Using the data from the monitoring of the system by RXTE we show that the orbital phase of X-ray flares from the source varies from phi X ~= 0.35 to phi X <…
A Population of Dust-rich Quasars at z ~ 1.5
Elvis, Martin; Willmer, Christopher N. A.; Magdis, Georgios E. +19 more
We report Herschel SPIRE (250, 350, and 500 µm) detections of 32 quasars with redshifts 0.5 <=z < 3.6 from the Herschel Multi-tiered Extragalactic Survey (HerMES). These sources are from a MIPS 24 µm flux-limited sample of 326 quasars in the Lockman Hole Field. The extensive multi-wavelength data available in the field permit con…
Star Formation History in Two Fields of the Small Magellanic Cloud Bar
Anderson, J.; Cignoni, M.; Tosi, M. +5 more
The Bar is the most productive region of the Small Magellanic Cloud in terms of star formation but also the least studied one. In this paper, we investigate the star formation history of two fields located in the SW and in the NE portion of the Bar using two independent and well-tested procedures applied to the color-magnitude diagrams of their st…
The Limit of Magnetic-shear Energy in Solar Active Regions
Moore, Ronald L.; Sterling, Alphonse C.; Falconer, David A.
It has been found previously, by measuring from active-region magnetograms a proxy of the free energy in the active region's magnetic field, (1) that there is a sharp upper limit to the free energy the field can hold that increases with the amount of magnetic field in the active region, the active region's magnetic flux content, and (2) that most …
The Remarkable High Pressure of the Local Leo Cold Cloud
Peek, J. E. G.; Heiles, Carl; Meyer, David M. +1 more
Using the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope, we have obtained high-resolution ultraviolet spectra of the C I absorption toward two stars behind the Local Leo Cold Cloud (LLCC). At a distance (≈20 pc) that places it well inside the Local Bubble, the LLCC is the nearest example of the coldest known (T ≈ …
Deep X-Ray Observations of the Young High-magnetic-field Radio Pulsar J1119-6127 and Supernova Remnant G292.2-0.5
Ng, C. -Y.; Shannon, R.; Weltevrede, P. +4 more
High-magnetic-field radio pulsars are important transition objects for understanding the connection between magnetars and conventional radio pulsars. We present a detailed study of the young radio pulsar J1119-6127, which has a characteristic age of 1900 yr and a spin-down-inferred magnetic field of 4.1 × 1013 G, and its associated supe…