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Evolution of the luminosity function and obscuration of active galactic nuclei: comparison between X-ray and infrared
Han, Zhanwen; Zhang, Fenghui; Wang, Bo +2 more
We present a detailed comparison between the 2-10 keV hard X-ray and infrared (IR) luminosity functions (LFs) of active galactic nuclei (AGNs). The composite X-ray to IR spectral energy distributions (SEDs) of AGNs, which are used to compare the hard X-ray LF (HXLF) and the IRLF, are modelled with a simple, but well-tested torus model, based on th…
Suzaku study of the centrally brightened supernova remnant G272.2-3.2
Sezer, A.; Gök, F.
In this paper, we present the results from a Suzaku observation of the Galactic supernova remnant G272.2-3.2. The spectra of G272.2-3.2 are well fitted by a single-temperature variable abundance non-equilibrium ionization (VNEI) model with an electron temperature kTe∼ 0.77 keV, an ionization time-scale τ∼ 6.5 × 1010 cm-3…
Automated measurement of redshifts from mid-infrared low-resolution spectroscopy
Hernán Caballero, Antonio
Obtaining accurate redshifts from mid-infrared (MIR) low-resolution (R ∼ 100) spectroscopy is challenging because the wavelength resolution is too low to detect narrow lines in most cases. Yet, the number of degrees of freedom and diversity of spectral features are too high for regular spectral energy distribution (SED) fitting techniques to be co…
Suppression of X-rays during an optical outburst of the helium dwarf nova KL Dra
Barclay, Thomas; Ramsay, Gavin; Wheatley, Peter J. +2 more
KL Dra is a helium-accreting AM CVn binary system with an orbital period close to 25 min. Approximately every 60 d there is a 4-mag optical outburst lasting ∼10 d. We present the most sensitive X-ray observations made of an AM CVn system during an outburst cycle. A series of eight observations were made using XMM-Newton which started shortly after…
Radio detection of nebulae around four luminous blue variable stars in the Large Magellanic Cloud
Umana, G.; Agliozzo, C.; Noriega-Crespo, A. +5 more
The nebulae associated with four luminous blue variables (LBVs) in the Large Magellanic Cloud (LMC) have been observed at 5.5 and 9 GHz using the Australia Telescope Compact Array, and radio emission has been detected for first time in sources R127, R143, S61 and S119. The radio maps of the nebulae have an angular resolution of ∼1.5 arcsec and a s…
Spitzer Observations of Shock-excited Hydrogen Deuteride in IC 443C, HH 7, and HH 54: Probing the Gas-phase Deuterium Abundance in the Dense Interstellar Medium
Watson, Dan M.; Yuan, Yuan; Neufeld, David A. +2 more
We present and analyze observations—carried out using the Infrared Spectrograph (IRS) on the Spitzer Space Telescope—of the R(3) and R(4) pure rotational lines of hydrogen deuteride (HD) detected from shock-heated material associated with the supernova remnant IC 443C and with the Herbig-Haro objects HH 7 and HH 54. Assuming a continuous temperatu…
An extended XMM-Newton observation of the Seyfert galaxy NGC 4051 - III. Fe K emission and absorption
Vaughan, S.; Pounds, K. A.
An extended XMM-Newton observation of the Seyfert 1 galaxy NGC 4051 in 2009 detected a photoionized outflow with a complex absorption-line velocity structure and a broad correlation of velocity with ionization parameter, shown by Pounds & Vaughan to be consistent with a highly ionized, high-velocity wind running into the interstellar medium or…
Electromagnetic models and inversion techniques for Titan’s Ontario Lacus depth estimation from Cassini RADAR data
Hayes, Alexander G.; Notarnicola, Claudia; Wye, Lauren +3 more
Since 2004, Cassini RADAR, operating at 13.8 GHz as a radiometer, scatterometer, altimeter and synthetic aperture radar (SAR), provides a vast amount of data, suggesting new scenarios for Titan’s morphology and evolution. An important result was the detection of lakes constituted by liquid hydrocarbons, thus supporting the hypothesis of a methane …
The Huygens surface science package (SSP): Flight performance review and lessons learned
Lorenz, R. D.; Leese, M. R.; Hathi, B. +1 more
The Surface Science Package (SSP) was one of six instruments flown onboard the Huygens probe to Titan, the largest moon of Saturn, in the framework of the NASA/ESA/ASI Cassini-Huygens mission (Matson et al., 2002). The SSP operated throughout the probe's descent and after landing on Titan on 14th January 2005. This paper reviews scientific results…
The Evolution of Sunspot Magnetic Fields Associated with a Solar Flare
Gallagher, Peter T.; Murray, Sophie A.; Bloomfield, D. Shaun
Solar flares occur due to the sudden release of energy stored in active-region magnetic fields. To date, the precursors to flaring are still not fully understood, although there is evidence that flaring is related to changes in the topology or complexity of an active-region's magnetic field. Here, the evolution of the magnetic field in active regi…