Search Publications
A partial eclipse of the heart: the absorbed X-ray low state in Mrk 1048
Schartel, N.; Santos-Lleó, M.; Fabian, A. C. +4 more
We present two new XMM-Newton observations of an unprecedented low-flux state in the Seyfert 1 Mrk 1048 (NGC 985), taken in 2013. The X-ray flux below 1 keV drops by a factor of 4-5, whereas the spectrum above 5 keV is essentially unchanged. This points towards an absorption origin for the low state, and we confirm this with spectral fitting, find…
The Herschel Fornax Cluster Survey II: FIR properties of optically selected Fornax cluster galaxies
Bianchi, S.; De Looze, I.; Auld, R. +13 more
The Herschel Fornax Cluster Survey is a deep, far-infrared (FIR) survey of the Fornax cluster. The survey is in five Herschel bands (100-500 µm) and covers an area of 16 deg2 centred on NGC 1399. This paper presents photometry, detection rates, dust masses, and temperatures using an optically selected sample from the Fornax Cluste…
Photospheric downward plasma motions in the quiet Sun
Ruiz Cobo, B.; Quintero Noda, C.; Orozco Suárez, D.
Context. We analyze spectropolarimetric data taken with the Hinode spacecraft in quiet solar regions at the disk center. Distorted redshifted Stokes V profiles are found that show a characteristic evolution that always follows the same sequence of phases.
Aims: We aim to characterize the statistical properties of these events and recover the …
Short-term Variability of X-Rays from Accreting Neutron Star Vela X-1. II. Monte Carlo Modeling
Makishima, Kazuo; Takahashi, Tadayuki; Odaka, Hirokazu +3 more
We develop a Monte Carlo Comptonization model for the X-ray spectrum of accretion-powered pulsars. Simple, spherical, thermal Comptonization models give harder spectra for higher optical depth, while the observational data from Vela X-1 show that the spectra are harder at higher luminosity. This suggests a physical interpretation where the optical…
Observed decline in Titan's thermospheric methane due to solar cycle drivers
Waite, J. H.; Perryman, R.; Bell, J. M. +1 more
We present Cassini Ion and Neutral Mass Spectrometer observations of Titan's N2 and CH4 from Cassini flybys of Titan spanning the time period from 2004 to 2013 representing 9 years of in situ neutral density observations. This data reveal an upward trend in CH4 mixing ratios during the extended solar minimum encoun…
PdBI Cold Dust Imaging of Two Extremely Red H - [4.5] > 4 Galaxies Discovered with SEDS and CANDELS
Dunlop, J. S.; Castellano, M.; Krips, M. +11 more
We report Plateau de Bure Interferometer (PdBI) 1.1 mm continuum imaging toward two extremely red H - [4.5] > 4 (AB) galaxies at z > 3, which we have previously discovered making use of Spitzer SEDS and Hubble Space Telescope CANDELS ultra-deep images of the Ultra Deep Survey field. One of our objects is detected on the PdBI map with a 4.3σ …
K-shell Photoabsorption of Magnesium Ions
García, J.; Kallman, T. R.; Gatuzz, E. +4 more
X-ray photoabsorption cross sections have been computed for all magnesium ions with three or more electrons using the R-matrix method. A comparison with other available data for Mg II-Mg X shows good qualitative agreement in the resultant resonance shapes. However, for the lower ionization stages, and for singly ionized Mg II in particular, the pr…
Investigating CXOU J163802.6-471358: A New Pulsar Wind Nebula in the Norma Region?
Kaspi, Victoria M.; Tomsick, John A.; Gotthelf, Eric V. +2 more
We present the first analysis of the extended source CXOU J163802.6-471358, which was discovered serendipitously during the Chandra X-ray survey of the Norma region of the Galactic spiral arms. The X-ray source exhibits a cometary appearance with a point source and an extended tail region. The complete source spectrum is fitted well with an absorb…
Kinematics of powerful jets from intermediate-mass protostars in the Carina nebula
Smith, Nathan; Reiter, Megan
We present measurements of proper motions and radial velocities of four powerful Herbig-Haro (HH) jets in the Carina nebula: HH 666, HH 901, HH 902, and HH 1066. Two epochs of Hubble Space Telescope imaging separated by a time baseline of ∼4.4 yr provide proper motions that allow us to measure the transverse velocities of the jets, while ground-ba…
The current system associated with the boundary of plasma bubbles
Parks, George K.; Zong, Qiu-Gang; Zhao, Duo +7 more
The current system associated with the boundary of plasma bubbles in the Earth's magnetotail has been studied by employing Cluster multipoint observations. We have investigated the currents in both the dipolarization front (DF, leading edge of the plasma bubble) and the trailing edge of the plasma bubble. The distribution of currents at the edge i…