Search Publications
On the Variations of Fundamental Constants and Active Galactic Nucleus Feedback in the Quasi-stellar Object Host Galaxy RXJ0911.4+0551 at z = 2.79
Menten, K. M.; Walter, F.; Henkel, C. +4 more
We report on sensitive observations of the CO(J = 7→6) and C I(3 P 2 → 3 P 1) transitions in the z = 2.79 QSO host galaxy RXJ0911.4+0551 using the IRAM Plateau de Bure interferometer. Our extremely high signal-to-noise spectra combined with the narrow CO line width of this source (FWHM = 120 km s-1<…
On the Relationship between the Coronal Magnetic Decay Index and Coronal Mass Ejection Speed
Xu, Yan; Liu, Chang; Jing, Ju +1 more
Numerical simulations suggest that kink and torus instabilities are two potential contributors to the initiation and prorogation of eruptive events. A magnetic parameter called the decay index (i.e., the coronal magnetic gradient of the overlying fields above the eruptive flux ropes) could play an important role in controlling the kinematics of er…
Interferometric CO(3-2) Observations toward the Central Region of NGC 1068
Matsushita, Satoki; Hwang, Chorng-Yuan; Espada, Daniel +2 more
We present CO(3-2) interferometric observations of the central region of the Seyfert 2 galaxy NGC 1068 using the Submillimeter Array, together with CO(1-0) data taken with the Owens Valley Radio Observatory Millimeter Array. Both the CO(3-2) and CO(1-0) emission lines are mainly distributed within ~5 arcsec of the nucleus and along the spiral arms…
NGC 5548: Lack of a Broad Fe Kα Line and Constraints on the Location of the Hard X-Ray Source
Liu, Y.; Elvis, M.; Krongold, Y. +2 more
We present an analysis of the co-added and individual 0.7-40 keV spectra from seven Suzaku observations of the Sy 1.5 galaxy NGC 5548 taken over a period of eight weeks. We conclude that the source has a moderately ionized, three-zone warm absorber, a power-law continuum, and exhibits contributions from cold, distant reflection. Relativistic refle…
Discovery of Variability of the Progenitor of SN 2011dh in M 51 Using the Large Binocular Telescope
Kochanek, C. S.; Stanek, K. Z.; Gerke, J. R. +1 more
We show that the candidate progenitor of the core-collapse SN 2011dh in M 51 (8 Mpc away) was fading by 0.039 ± 0.006 mag yr-1 during the 3 years prior to the supernova, and that this level of variability is moderately unusual for other similar stars in M 51. While there are uncertainties about whether the true progenitor was a blue com…
Large-scale Magnetic Helicity Fluxes Estimated from MDI Magnetic Synoptic Charts over the Solar Cycle 23
Zhang, Hongqi; Yang, Shangbin
To investigate the characteristics of large-scale and long-term evolution of magnetic helicity with solar cycles, we use the method of Local Correlation Tracking to estimate the magnetic helicity evolution over solar cycle 23 from 1996 to 2009 using 795 MDI magnetic synoptic charts. The main results are as follows: the hemispheric helicity rule st…
Hard X-Ray and Ultraviolet Observations of the 2005 January 15 Two-ribbon Flare
Qiu, J.; Cheng, J. X.; Kerr, G.
It is well known that two-ribbon flares observed in Hα and ultraviolet (UV) wavelengths mostly exhibit compact and localized hard X-ray (HXR) sources. In this paper, we present comprehensive analysis of a two-ribbon flare observed in UV 1600 Å by Transition Region and Coronal Explorer and in HXRs by Reuven Ramaty High Energy Solar Spectroscopic Im…
Suzaku Observations of the Non-thermal Supernova Remnant HESS J1731-347
Acero, Fabio; Klochkov, Dmitry; Bamba, Aya +7 more
A detailed analysis of the non-thermal X-ray emission from the northwestern and southern parts of the supernova remnant (SNR) HESS J1731-347 with Suzaku is presented. The shell portions covered by the observations emit hard and lineless X-rays. The spectrum can be reproduced by a simple absorbed power-law model with a photon index Γ of 1.8-2.7 and…
Spin-down Measurement of PSR J1813-1749: The Energetic Pulsar Powering HESS J1813-178
Camilo, F.; Gotthelf, E. V.; Halpern, J. P.
Two new X-ray timing observations of the 44.7 ms pulsar in G12.82-0.02/HESS J1813-178 were obtained with Chandra and XMM-Newton to determine its precise spin-down rate. With a period derivative of \dot{P} = 1.265\times 10^{-13}, PSR J1813-1749 is the third most energetic pulsar in the Galaxy, having spin-down luminosity \dot{E} = 5.6\times 10^{37}…
Herschel PACS Observations and Modeling of Debris Disks in the Tucana-Horologium Association
Ménard, F.; Dent, W. R. F.; Krivov, A. V. +9 more
We present Herschel PACS photometry of 17 B- to M-type stars in the 30 Myr old Tucana-Horologium Association. This work is part of the Herschel Open Time Key Programme "Gas in Protoplanetary Systems". 6 of the 17 targets were found to have infrared excesses significantly greater than the expected stellar IR fluxes, including a previously unknown d…