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Global Twist of Sunspot Magnetic Fields Obtained from High-Resolution Vector Magnetograms
Tiwari, Sanjiv Kumar; Venkatakrishnan, P.; Sankarasubramanian, K.
The presence of fine structures in sunspot vector magnetic fields has been confirmed from Hinode as well as other earlier observations. We studied 43 sunspots based on the data sets taken from ASP/DLSP, Hinode (SOT/SP), and SVM (USO). In this Letter, (1) we introduce the concept of signed shear angle (SSA) for sunspots and establish its importance…
Imaging the Circumnuclear Region of NGC 1365 with Chandra
Elvis, M.; Fabbiano, G.; Howell, J. H. +4 more
We present the first Chandra/ACIS imaging study of the circumnuclear region of the nearby Seyfert galaxy NGC 1365. The X-ray emission is resolved into pointlike sources and complex, extended emission. The X-ray morphology of the extended emission shows a biconical soft X-ray-emission region extending ~5 kpc in projection from the nucleus, coincide…
The Mid-Infrared Continua of Seyfert Galaxies
Kraemer, S. B.; Crenshaw, D. M.; Richards, Gordon T. +1 more
An analysis of archival mid-infrared (mid-IR) spectra of Seyfert galaxies from the Spitzer Space Telescope observations is presented. We characterize the nature of the mid-IR active nuclear continuum by subtracting a template starburst spectrum from the Seyfert spectra. The long wavelength part of the spectrum contains a strong contribution from t…
X-Ray Insights into the Nature of Weak Emission-Line Quasars at High Redshift
Brandt, W. N.; Strauss, Michael A.; Anderson, Scott F. +5 more
We present Chandra observations of nine high-redshift quasars (z = 2.7-5.9) discovered by the Sloan Digital Sky Survey with weak or undetectable high-ionization emission lines in their UV spectra (WLQs). Adding archival X-ray observations of six additional sources of this class has enabled us to place the strongest constraints yet on the X-ray pro…
Rotation Measures Across Parsec-Scale Jets of Fanaroff-Riley Type I Radio Galaxies
O'Dea, C. P.; Baum, S. A.; Kharb, P. +2 more
We present the results of a parsec-scale polarization study of three FRI radio galaxies—3C66B, 3C78, and 3C264—obtained with Very Long Baseline Interferometry at 5, 8, and 15 GHz. Parsec-scale polarization has been detected in a large number of beamed radio-loud active galactic nuclei, but in only a handful of the relatively unbeamed radio galaxie…
Three-Dimensional Structure and Energy Balance of a Coronal Mass Ejection
Raymond, J. C.; Ko, Y. -K.; Lee, J. -Y. +1 more
The Ultraviolet Coronagraph Spectrometer (UVCS) observed Doppler-shifted material of a partial halo coronal mass ejection (CME) on 2001 December 13. The observed ratio of [O V]/O V] is a reliable density diagnostic important for assessing the state of the plasma. Earlier UVCS observations of CMEs found evidence that the ejected plasma is heated lo…
Simultaneous Multiwavelength Observation of Mkn 501 in a Low State in 2006
Maraschi, L.; Covino, S.; Antonelli, L. A. +147 more
We present results of the multiwavelength campaign on the TeV blazar Mkn 501 performed in 2006 July, including MAGIC for the very-high-energy (VHE) γ-ray band and Suzaku for the X-ray band. A VHE γ-ray signal was clearly detected with an average flux above 200 GeV of ~20% of the Crab Nebula flux, which indicates a low state of source activity in t…
X-ray Monitoring of Ultraluminous X-ray Sources
Feng, Hua; Kaaret, Philip
X-ray monitoring observations were performed with the Swift observatory of the ultraluminous X-ray sources Holmberg IX X-1, NGC 5408 X-1, and NGC 4395 X-2 and also of the nuclear X-ray source in NGC 4395. Holmberg IX X-1 remains in the hard X-ray spectral state as its flux varies by a factor of 7 up to a (isotropic) luminosity of 2.8 × 1040
Laboratory Experiments, Numerical Simulations, and Astronomical Observations of Deflected Supersonic Jets: Application to HH 110
Williams, R. J. R.; Hartigan, P.; Frank, A. +7 more
Collimated supersonic flows in laboratory experiments behave in a similar manner to astrophysical jets provided that radiation, viscosity, and thermal conductivity are unimportant in the laboratory jets and that the experimental and astrophysical jets share similar dimensionless parameters such as the Mach number and the ratio of the density betwe…
A Spectroscopically Confirmed Excess of 24 µm Sources in a Super Galaxy Group at z = 0.37: Enhanced Dusty Star Formation Relative to the Cluster and Field Environment
Saintonge, Amélie; Tran, Kim-Vy H.; Moustakas, John +5 more
To trace how dust-obscured star formation varies with environment, we compare the fraction of 24 µm sources in a super galaxy group to the field and a rich galaxy cluster at z ~ 0.35. We draw on multi-wavelength observations9Based on observations made with (1) The ESO telescopes at Paranal Observatories under program IDs 072.A-036…