Optical integral field spectroscopy of the extended line emission around six radio-loud quasars

We present integral field spectroscopy of a small sample of radio-loud quasars at intermediate redshift (0.26<z<0.60), most of which are associated with large radio sources. All have oxygen line emission extended over tens of kiloparcsecs, and these nebulae display a diverse range in both morphology and kinematic behaviour. Two quasars show 'plumes' of extended line emission, two show a clumpy structure and a further one shows a smooth distribution. There is no clear pattern with regard to the distribution of the ionized gas in relation to the radio source axis; the extended emission-line regions are found both parallel and perpendicular - and also totally unrelated to - the radio axis. The velocity structure of the ionized gas ranges from essentially static to apparent smooth rotation, and in two cases, show a clear association with the radio source. Given the disparity in properties, the nebulae all show a surprisingly similar ionization state, as measured by the extended lines of [OII] and [OIII]. Assuming the gas is ionized by at least the nearby quasar nucleus, we use the emission line ratios to infer a pressure in the ionized gas; in all cases we find it to be at high pressure, suggesting confinement by an external (probably intracluster) medium.Comment: 14 pages, 18 figures, 10 of which are presented separately; accepted for publication in MNRA

United States budgetary costs of Post-9/11 wars through FY2018

Originally published on the Watson Institute's Costs of War Project website: http://watson.brown.edu/costsofwar/papers/2017/USBudgetaryCostsFY2018The costs to the United States of post-9/11 wars will total more than $5.6 trillion by the end of fiscal year 2018, a new Costs of War report finds, and the average American taxpayer has spent$23,386 on these wars since 2001. “The U.S. wars in Iraq, Syria, Afghanistan and Pakistan, and the increased spending on homeland security and the departments of defense, state and veterans affairs since the 9/11 attacks have cost more than $4.3 trillion in current dollars through fiscal year 2017,” said Neta Crawford, Costs of War co-director and a professor of political science at Boston University. “Adding likely costs for fiscal year 2018 and estimated future obligations for veterans’ care, the costs of war total more than$5.6 trillion.

Noise requirements from a military point of view

External and internal aircraft noise requirements are discussed in terms of application to military helicopters. The impact of the application of noise reduction technology to comply with FAA standards on cost and performance is emphasized

VLT near-infrared spectra of hard serendipitous Chandra sources

We present near-infrared long-slit spectra of eight optically-dim X-ray sources obtained with ISAAC on the Very Large Telescope. Six of the sources have hard X-ray emission with a significant fraction of the counts emerging above 2 keV. All were discovered serendipitously in the fields of three nearby galaxy clusters observed with Chandra, and identified through near-infrared imaging. The X-ray fluxes lie close to the break in the source counts. Two of the sources show narrow emission lines, and a third has a broad line. One of the narrow line-emitting sources has a clear redshift identification at z=2.18, while the other has a tentative determination based on the highest redshift detection of He I 10830 at z=1.26. The remainder have featureless spectra to deep limiting equivalent widths of 20--60 angstroms and line flux approx= 5 x 10^{-17} erg/s/cm^2 in the K-band. High-quality J, H and Ks--band images of the sources were combined with archival optical detections or limits to estimate a photometric redshift for six. Two sources show complex double morphology. The hard sources have spectral count ratios consistent with heavily obscured AGN, while the host galaxy emits much of the optical and near-infrared flux. The most likely explanation for the featureless continua is that the line photons are being scattered or destroyed by optically-thick gas and associated dust with large covering fractions.Comment: Replaced in response to problems with the PDF version of Fig 4 at arxiv.org, but not at the mirror sites (lanl.gov, soton.ac.uk). No content change