Search Publications
The Relative Intensity Calibration of Hinode/EIS and SOHO/SUMER
Young, P. R.; Landi, E.
In this work, we have used simultaneous observations of the quiet Sun above the solar west limb obtained with the Hinode/Extreme ultraviolet Imaging Spectrograph and SOHO/SUMER instruments to determine their relative intensity calibration. We used two different methods: intensity ratios of lines emitted by the same upper level and observed in the …
Probing the Transition Between the Synchrotron and Inverse-compton Spectral Components of 1ES 1959+650
Greiner, J.; Ajello, M.; Schady, P. +5 more
1ES 1959+650 is one of the most remarkable high-peaked BL Lacertae objects (HBL). In 2002, it exhibited a TeV γ-ray flare without a similar brightening of the synchrotron component at lower energies. This orphan TeV flare remained a mystery. We present the results of a multifrequency campaign, triggered by the INTEGRAL IBIS detection of 1ES 1959+6…
An Optical-infrared Study of the Young Multipolar Planetary Nebula NGC 6644
Zhang, Yong; Volk, Kevin; Kwok, Sun +2 more
High-resolution Hubble Space Telescope imaging of the compact planetary nebula NGC 6644 has revealed two pairs of bipolar lobes and a central ring lying close to the plane of the sky. From mid-infrared imaging obtained with the Gemini Telescope, we have found a dust torus which is oriented nearly perpendicular to one pair of the lobes. We suggest …
Tiny Pores Observed by Hinode/Solar Optical Telescope
Chae, Jongchul; Cho, Kyung-Suk; Kim, Yeon-Han +2 more
The study of pores, small penumbraless sunspots, can give us a chance to understand how strong magnetic fields interact with convective motions in the photosphere. For a better understanding of this interaction, we investigate the temporal variation of several tiny pores smaller than 2''. These pores were observed by the Solar Optical Telescope on…
The Hard X-ray View of Reflection, Absorption, and the Disk-Jet Connection in the Radio-loud AGN 3C 33
Hardcastle, M. J.; Reeves, J. N.; Lee, J. C. +3 more
We present results from Suzaku and Swift observations of the nearby radio galaxy 3C 33, and investigate the nature of absorption, reflection, and jet production in this source. We model the 0.5-100 keV nuclear continuum with a power law that is transmitted either through one or more layers of pc-scale neutral material, or through a modestly ionize…
Unveiling Far-infrared Counterparts of Bright Submillimeter Galaxies Using PACS Imaging
Berta, S.; Magnelli, B.; Nordon, R. +35 more
We present a search for Herschel-PACS counterparts of dust-obscured, high-redshift objects previously selected at submillimeter and millimeter wavelengths in the Great Observatories Origins Deep Survey North field. We detect 22 of 56 submillimeter galaxies (SMGs, 39%) with a signal-to-noise ratio of >=3 at 100 µm down to 3.0 mJy, and/or a…
The Young Interstellar Bubble Within the Rosette Nebula
Gull, T. R.; Freire Ferrero, R.; Bruhweiler, F. C. +1 more
We use high-resolution International Ultraviolet Explorer (IUE) data and the interstellar (IS) features of highly ionized Si IV and C IV seen toward the young, bright OB stars of NGC 2244 in the core of the Rosette Nebula to study the physics of young IS bubbles. Two discrete velocity components in Si IV and C IV are seen toward stars in the 6.2 p…
On the Flare Induced High-Frequency Global Waves in the Sun
García, R. A.; Venkatakrishnan, P.; Kumar, Brajesh +1 more
Recently, Karoff & Kjeldsen presented evidence of strong correlation between the energy in the high-frequency part (5.3 < ν < 8.3 mHz) of the acoustic spectrum of the Sun and the solar X-ray flux. They have used disk-integrated intensity observations of the Sun obtained from the Variability of solar IRradiance and Gravity Oscillations in…
Evidence of a Warm Absorber That Varies with Quasi-periodic Oscillation Phase in the Active Galactic Nucleus RE J1034+396
Miller, Jon M.; Maitra, Dipankar
A recent observation of the nearby (z = 0.042) narrow-line Seyfert 1 galaxy RE J1034+396 on 2007 May 31 showed strong quasi-periodic oscillations (QPOs) in the 0.3-10 keV X-ray flux. We present phase-resolved spectroscopy of this observation, using data obtained by the EPIC PN detector on board XMM-Newton. The "low" phase spectrum, associated with…
Population I Wolf-Rayet Runaway Stars: The Case of WR124 and its Expanding Nebula M1-67
Crowther, P. A.; Moffat, A. F. J.; Marchenko, S. V.
In 1997 and 2008 we used the WFPC2 camera on board the Hubble Space Telescope to obtain two sets of narrow-band Hα images of the runaway Wolf-Rayet (WR) star WR 124 surrounded by its nebula M1-67. This two-epoch imaging provides an expansion parallax and thus a practically assumption-free geometric distance to the nebula, d = 3.35 ± 0.67 kpc. Comb…