An XMM-Newton view of FeKα in high-mass X-ray binaries

We present a comprehensive analysis of the whole sample of available XMM-Newton observations of high-mass X-ray binaries (HMXBs) until August 2013, focusing on the FeKα emission line. This line is key to better understanding the physical properties of the material surrounding the X-ray source within a few stellar radii (the circumstellar medium). We collected observations from 46 HMXBs and detected FeKα in 21 of them. We used the standard classification of HMXBs to divide the sample into different groups. We find that (1) different classes of HMXBs display different qualitative behaviours in the FeKα spectral region. This is visible especially in SGXBs (showing ubiquitous Fe fluorescence but not recombination Fe lines) and in γ Cass analogues (showing both fluorescent and recombination Fe lines). (2) FeKα is centred at a mean value of 6.42 keV. Considering the instrumental and fits uncertainties, this value is compatible with ionization states that are lower than Fe xviii. (3) The flux of the continuum is well correlated with the flux of the line, as expected. Eclipse observations show that the Fe fluorescence emission comes from an extended region surrounding the X-ray source. (4) We observe an inverse correlation between the X-ray luminosity and the equivalent width of FeKα (EW). This phenomenon is known as the X-ray Baldwin effect. (5) FeKα is narrow (σline< 0.15 keV), reflecting that the reprocessing material does not move at high speeds. We attempt to explain the broadness of the line in terms of three possible broadening phenomena: line blending, Compton scattering, and Doppler shifts (with velocities of the reprocessing material V ~ 1000 km s-1). (6) The equivalent hydrogen column (NH) directly correlates to the EW of FeKα, displaying clear similarities to numerical simulations. It highlights the strong link between the absorbing and the fluorescent matter. (7) The observed NH in supergiant X-ray binaries (SGXBs) is in general higher than in supergiant fast X-ray transients (SFXTs). We suggest two possible explanations: different orbital configurations or a different interaction compact object – wind. (8) Finally, we analysed the sources IGR J16320-4751 and 4U 1700-37 in more detail, covering several orbital phases. The observed variation in NH between phases is compatible with the absorption produced by the wind of their optical companions. The results clearly point to a very important contribution of the donor’s wind in the FeKα emission and the absorption when the donor is a supergiant massive star.

Engravings of a plan and an exterior view of Harvard Hall drawn by Pierre Eugène du Simitière, (photographic prints, photostats, and negative photostats), [ca. 1764]

The floor plan details all three floors of Harvard Hall, including its cellars, kitchen, chapel, and library. The items in this folder were reproduced from "The Burning of Harvard Hall, 1764, and its consequences," presented by F. Apthorp Foster at the April 1911 meeting of the Colonial Society of Massachusetts, and published in the Publications of the Colonial Society of Massachusetts, Volume XIV. The floor plan and exterior views were created by Pierre Eugène du Simitière in circa 1764. The original drawings are held in the Pierre Eugène du Simitière collection in the Ridgeway Branch of the Library Company of Philadelphia.

Hollis Hall…S.E. [Southeast] view, ca. 1807

Pencil drawing of Hollis Hall, southeast view .

Hollis Hall…N.W. [Northwest] view, ca. 1808

Pencil drawing of Hollis Hall, northwest view.

Holworthy Hall…S.W. [Southwest] View, 1829

Pen and ink drawing of Holworthy Hall, watermarked 1829.

A s.w. [south west] view of Mass. [Massachusetts] Hall, [1828]

Pencil drawing of South West view of Massachusetts Hall.

Stoughton Hall..N.W. [Northwest] View, 1827

Pen and ink drawing of a northwest view of Stoughton Hall, watermarked 1827

Stoughton Hall..S.E. [Southeast] View, 1827

Pen and ink drawing of a southeast view of Stoughton Hall, watermarked 1827

Birds eye view of trolley routes in New England, 1904 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Trolley wayfinder, birds eye view of trolley routes in New England, published by the New England Street Railway Club, 1904. This is a perspective map not drawn to scale. Covers eastern portion of New England from Lewiston, Maine, to Newport, Rhode Island. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Massachusetts State Plane Coordinate System, Mainland Zone (in Feet) (Fipszone 2001). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, or other information associated with the principal map. This map shows features such as steam railroads, electric railroads, parks, buildings, drainage, and more. Relief and some features are shown pictorially. Includes 7 insets. This layer is part of a selection of digitally scanned and georeferenced historic maps of Massachusetts from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of regions, originators, ground condition dates (1755-1922), scales, and purposes. The digitized selection includes maps of: the state, Massachusetts counties, town surveys, coastal features, real property, parks, cemeteries, railroads, roads, public works projects, etc.

Still the “pivot”: Russia’s self-conception and view of the euro crisis as perceived in public opinion and the Rossiiskaya Gazeta, 2011-12. EU Centre in Singapore Working Paper No. 8, August 2012

In his influential and disputed 1904 lecture, “The Geographical Pivot of History,” Halford Mackinder argued that the Russian heartland was the fulcrum of many historical and geostrategic currents across Eurasian space. While the thesis has been thought surpassed by recent technological advances in transportation, it serves as a useful heuristic device to open certain thematic lines of analysis apparent in the presentation of the ongoing “EUrocrisis” by the country’s newspaper of record, the Rossiiskaya Gazeta.

The Mercosur-EU preferential trade agreement. A view from Europe. CEPS Working Document No. 377, February 2013

This paper first aims at assessing the economic and political importance of Mercosur for the EU’s interests in the short and medium run – say for the one or two coming decades or so. As Mercosur’s size is largely determined by Brazil’s size, this paper focuses on Brazil – although the paper assumes that, from Brazil’s perspective, a Brazil–EU preferential trade agreement (PTA) is a non-starter. It then aims at positioning the Mercosur–EU (MEU) PTA in the context of the EU’s current trade policy. In particular, it tries to assess, once one takes into account all the crucial goals to be met by the EU, whether the EU is likely to find the time and the resources necessary for dealing properly with a MEU PTA; this effort is notably complicated by the very divergent views on the role of trade between Brazil on the one hand, and Argentina and Venezuela, on the other hand. Finally, the paper examines the PTA options that can be seen as reasonably feasible. It suggests that, unless there are dramatic changes in Mercosur’s present trajectory, the goal of negotiating a fully-fledged MEU PTA should be set aside for some time – at least a decade or so. This does not mean leaving the negotiating table, but rather focusing on negotiating topics that remain attractive to both sides in the current context, and manageable and flexible enough to overcome the broad general problems confronted by Mercosur and the EU.