The donor star of the X-ray pulsar X1908+075

High-mass X-ray binaries consist of a massive donor star and a compact object. While several of those systems have been well studied in X-rays, little is known for most of the donor stars as they are often heavily obscured in the optical and ultraviolet regime. There is an opportunity to observe them at infrared wavelengths, however. The goal of this study is to obtain the stellar and wind parameters of the donor star in the X1908+075 high-mass X-ray binary system with a stellar atmosphere model to check whether previous studies from X-ray observations and spectral morphology lead to a sufficient description of the donor star. We obtained H- and K-band spectra of X1908+075 and analysed them with the Potsdam Wolf-Rayet (PoWR) model atmosphere code. For the first time, we calculated a stellar atmosphere model for the donor star, whose main parameters are: Mspec = 15 ± 6 M⊙, T∗ = 23-3+6 kK, log geff = 3.0 ± 0.2 and log L/L⊙ = 4.81 ± 0.25. The obtained parameters point towards an early B-type (B0–B3) star, probably in a supergiant phase. Moreover we determined a more accurate distance to the system of 4.85 ± 0.50 kpc than the previously reported value.

The Goodness of Simultaneous Fits in ISIS

In a previous work, we introduced a tool for analyzing multiple datasets simultaneously, which has been implemented into ISIS. This tool was used to fit many spectra of X-ray binaries. However, the large number of degrees of freedom and individual datasets raise an issue about a good measure for a simultaneous fit quality. We present three ways to check the goodness of these fits: we investigate the goodness of each fit in all datasets, we define a combined goodness exploiting the logical structure of a simultaneous fit, and we stack the fit residuals of all datasets to detect weak features. These tools are applied to all RXTE-spectra from GRO 1008−57, revealing calibration features that are not detected significantly in any single spectrum. Stacking the residuals from the best-fit model for the Vela X-1 and XTE J1859+083 data evidences fluorescent emission lines that would have gone undetected otherwise.

Berlin, Germany, 1920 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Kiessling's grosser plan von Berlin : mit Voroten und Völlständiger Stadt - u. Ringbahn. It was published by Alexius Kiessling in 1920. Scale 1:20,000. Covers a portion of Berlin, Germany. Map in German. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Deutsches Hauptdreiecksnetz (DHDN) 3-degree Gauss-Kruger Zone 4 coordinate system. 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, index maps, legends, or other information associated with the principal map. This map shows features such as roads, railroads and stations, drainage, selected buildings, parks, ground cover, city districts, and more. Relief shown by spot heights.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Göttingen, Germany, ca. 1740 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Goettinga, urbs munitissima et splendida electoratus Brunsvico-Luneburgici Academia Georgia Augusta inclyta, accurate aere repraesentata à Matth. Seuttero, Geogr. Caesar, Aug. Vind. It was published by M. Seutter, ca. 1740. Scale [ca. 1:3,500]. Covers Göttingen, Germany. Map in German and Latin.The image inside the map neatline is georeferenced to the surface of the earth and fit to the Deutsches Hauptdreiecksnetz (DHDN) 3-degree Gauss-Kruger Zone 3 coordinate system. 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, index maps, legends, or other information associated with the principal map. This map shows features such as roads, drainage, built-up areas and selected buildings, fortifications, ground cover, and more. Includes indexes, illustrations, and view.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Hannover, Germany, ca. 1740 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Accurata et novissima repraesentatio ichnographica Hannoverae, sedis urbis et electoralis Brunsuico-Luneburgensis = Hannover, die Churfürst. Braunschweig-Lüneburg. Haupt- und Residentz-Stadt an der Leine gelegen, Aeri incidit et excudit Matthaeus Seutter, S. C. M. Geograph. It was published by M. Seutter ca. 1740. Scale [ca. 1:3,780]. Covers Hannover, Germany. Map in Latin and German.The image inside the map neatline is georeferenced to the surface of the earth and fit to the Deutsches Hauptdreiecksnetz (DHDN) 3-degree Gauss-Kruger Zone 3 coordinate system. 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, index maps, legends, or other information associated with the principal map. This map shows features such as roads, drainage, built-up areas and selected buildings, fortifications, ground cover, and more. Includes indexes, illustrations, and text.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Kiel, Germany, ca. 1736 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Die Herzogl. Holstein-Gottorp. Residenz- See- und Handelstadt Kiel sambt dessen Hafen in einem accuraten Plan u. Prospect entworfen = Sereniss. Ducis Holsato-Gottorpiensis Sedes et celebre Emporium Kilonium una cum ejus Portu ichno- et scenographice accurate delineatum, delineante G. C. Holmer. It was published by Officina Homanniana ca. 1736. Scale [ca. 1:4,000]. Covers Kiel, Germany. Map in German and Latin.Note: Two maps appear on this sheet. The larger scale map of Kiel is the portion of the image that has been georeferenced.The image inside the map neatline is georeferenced to the surface of the earth and fit to the Deutsches Hauptdreiecksnetz (DHDN) 3-degree Gauss-Kruger Zone 3 coordinate system. 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, index maps, legends, or other information associated with the principal map. This map shows features such as roads, drainage, built-up areas and selected buildings, fortifications, ground cover, and more. Includes also indexes and 2 views of Kiel.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Lübeck, Germany, ca. 1730 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Grund-Riss der Keyserlichen und des Heil. Röm. Reichs freyen stadt Lübeck, herausgegeben von Matth. Seutter, kayserl. Geogr. It was published by M. Seutter between 1730 and 1739. Covers Lübeck, Germany. Scale [ca. 1:5,600]. Map in German. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Deutsches Hauptdreiecksnetz (DHDN) 3-degree Gauss-Kruger Zone 4 coordinate system. 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, index maps, legends, or other information associated with the principal map. This map shows features such as roads, drainage, built-up areas and selected buildings, fortifications, ground cover, and more. Includes indexes, illustrations, and a view.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Berlin, Germany, 1748 (Image 1 of 4) (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Plan de la ville de Berlin : levé et dessiné par ordre et privilege privatif du Roy sous la direction du Marchall Comte de Schmettau, par Hildner approuvé par l'Academie Royale de Science â Berlin ; gravé sous la direction de G.F. Schmidt Graveur du Roy. It was published by l'Academie Royale de Science â Berlin in 1748. Scale [ca. 1:6,500]. Covers Berlin, Germany. This layer is image 1 of 4 total images of the four sheet source map, representing the northeast portion of the map. Map in French and German.The image inside the map neatline is georeferenced to the surface of the earth and fit to the Deutsches Hauptdreiecksnetz (DHDN) 3-degree Gauss-Kruger Zone 4 coordinate system. 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, index maps, legends, or other information associated with the principal map. This map shows features such as roads, drainage, built-up areas and selected buildings, fortification, parks, cemeteries, ground cover, and more. Relief shown by hachures. Includes also view and inset engravings: Prospect du Stadt Berlin von Süden gegen Norden -- 1. Prospect des grossen Platzes von Opera Hausse 2. der Cathol. Kirche St. Hedwig 3. und einer Seite des Marggraff Henrich. Pallais -- Prospect der Neuen Schloss u Dohm Kirche -- Prospect des Neuen Königl. Printz Heinrich. Pallais den Opern Hausse gegen über.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Berlin, Germany, 1748 (Image 2 of 4) (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Plan de la ville de Berlin : levé et dessiné par ordre et privilege privatif du Roy sous la direction du Marchall Comte de Schmettau, par Hildner approuvé par l'Academie Royale de Science â Berlin ; gravé sous la direction de G.F. Schmidt Graveur du Roy. It was published by l'Academie Royale de Science â Berlin in 1748. Scale [ca. 1:6,500]. Covers Berlin, Germany. This layer is image 2 of 4 total images of the four sheet source map, representing the southeast portion of the map. Map in French and German.The image inside the map neatline is georeferenced to the surface of the earth and fit to the Deutsches Hauptdreiecksnetz (DHDN) 3-degree Gauss-Kruger Zone 4 coordinate system. 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, index maps, legends, or other information associated with the principal map. This map shows features such as roads, drainage, built-up areas and selected buildings, fortification, parks, cemeteries, ground cover, and more. Relief shown by hachures. Includes also view and inset engravings: Prospect du Stadt Berlin von Süden gegen Norden -- 1. Prospect des grossen Platzes von Opera Hausse 2. der Cathol. Kirche St. Hedwig 3. und einer Seite des Marggraff Henrich. Pallais -- Prospect der Neuen Schloss u Dohm Kirche -- Prospect des Neuen Königl. Printz Heinrich. Pallais den Opern Hausse gegen über.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Berlin, Germany, 1748 (Image 3 of 4) (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Plan de la ville de Berlin : levé et dessiné par ordre et privilege privatif du Roy sous la direction du Marchall Comte de Schmettau, par Hildner approuvé par l'Academie Royale de Science â Berlin ; gravé sous la direction de G.F. Schmidt Graveur du Roy. It was published by l'Academie Royale de Science â Berlin in 1748. Scale [ca. 1:6,500]. Covers Berlin, Germany. This layer is image 3 of 4 total images of the four sheet source map, representing the northwest portion of the map. Map in French and German.The image inside the map neatline is georeferenced to the surface of the earth and fit to the Deutsches Hauptdreiecksnetz (DHDN) 3-degree Gauss-Kruger Zone 4 coordinate system. 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, index maps, legends, or other information associated with the principal map. This map shows features such as roads, drainage, built-up areas and selected buildings, fortification, parks, cemeteries, ground cover, and more. Relief shown by hachures. Includes also view and inset engravings: Prospect du Stadt Berlin von Süden gegen Norden -- 1. Prospect des grossen Platzes von Opera Hausse 2. der Cathol. Kirche St. Hedwig 3. und einer Seite des Marggraff Henrich. Pallais -- Prospect der Neuen Schloss u Dohm Kirche -- Prospect des Neuen Königl. Printz Heinrich. Pallais den Opern Hausse gegen über.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Berlin, Germany, 1748 (Image 4 of 4) (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Plan de la ville de Berlin : levé et dessiné par ordre et privilege privatif du Roy sous la direction du Marchall Comte de Schmettau, par Hildner approuvé par l'Academie Royale de Science â Berlin ; gravé sous la direction de G.F. Schmidt Graveur du Roy. It was published by l'Academie Royale de Science â Berlin in 1748. Scale [ca. 1:6,500]. Covers Berlin, Germany. This layer is image 4 of 4 total images of the four sheet source map, representing the southwest portion of the map. Map in French and German.The image inside the map neatline is georeferenced to the surface of the earth and fit to the Deutsches Hauptdreiecksnetz (DHDN) 3-degree Gauss-Kruger Zone 4 coordinate system. 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, index maps, legends, or other information associated with the principal map. This map shows features such as roads, drainage, built-up areas and selected buildings, fortification, parks, cemeteries, ground cover, and more. Relief shown by hachures. Includes also view and inset engravings: Prospect du Stadt Berlin von Süden gegen Norden -- 1. Prospect des grossen Platzes von Opera Hausse 2. der Cathol. Kirche St. Hedwig 3. und einer Seite des Marggraff Henrich. Pallais -- Prospect der Neuen Schloss u Dohm Kirche -- Prospect des Neuen Königl. Printz Heinrich. Pallais den Opern Hausse gegen über.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Berlin, Germany, 1895 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Plan von Berlin : mit sämtlichen Vororten und vollständiger Stadt- und Ringbahn, bearbeitet und herausgegeben von Julius Straube ; Geographisches Institut und Landkarten. It was published by Geographisches Institut und Landkarten-Verlag Jul. Straube in 1895. Scale 1:17,777. Covers Berlin, Germany. Map in German.The image inside the map neatline is georeferenced to the surface of the earth and fit to the Deutsches Hauptdreiecksnetz (DHDN) 3-degree Gauss-Kruger Zone 4 coordinate system. 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, index maps, legends, or other information associated with the principal map. This map shows features such as roads, railroads and stations, street railways, drainage, built-up areas and selected buildings, city districts, parks, and more.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Augsburg, Germany, 1740-1760 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Accurata recens delineata ichnographia celeberrimae liberae imperii civitatis ac Sueviae metropolis Augustae Vindelicorum = Neu verfertigt accurater Grund Riss der hochberühmten dess Heil. Röm. Reichs freyen u. dess schwäbischen Creisses Haupt Statt Augspurg, Ioh. Thomas Kraus, architectus et perspectivicus delineavit ; im Kupfer gestochen un verlegt von M. Seutter, I.R.K.M. geogr. It was published by Matthäus Seutter, between 1740 and 1760. Scale [ca. 1:4,500]. Covers Augsburg, Germany. Map in Latin and German. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Deutsches Hauptdreiecksnetz (DHDN) 3-degree Gauss-Kruger Zone 4 coordinate system. 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, index maps, legends, or other information associated with the principal map. This map shows features such as roads, drainage, built-up areas and selected buildings, fortifications, ground cover, and more. Relief shown pictorially. Includes indexes.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Erfurt, Germany, 1745 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Erfordiae primariae Thuringiae urbis novissima ichnographia, cura & studio prodiit C.A. Molitoris = Erfurth, der Haupt Stadt in Thüringen neuester mit Fleiss verfertigter Grundriss, ans Licht gestellt von Homaennischen Erben. It was published by Homannianis Heredibus in 1745. Scale [ca. 1:6,500]. Covers Erfurt, Germany. Map in Latin and German.The image inside the map neatline is georeferenced to the surface of the earth and fit to the Deutsches Hauptdreiecksnetz (DHDN) 3-degree Gauss-Kruger Zone 4 coordinate system. 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, index maps, legends, or other information associated with the principal map. This map shows features such as roads, drainage, built-up areas and selected buildings, fortifications, ground cover, and more. Includes indexes and panorama of the city, below the map.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Erlangen, Germany, 1721 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Accurater Grundris und Gegend des Hoch-Fürstl. Brandenb. Bayreuth. neu-erbauten Stadt Christian-Erlang : samt denen Prospecten des Hoch-Fürstl. Residenz-Schloss und anderer ansehnlichen Gebäuen, wie auch der nach ihrem fatalen Brand wieder gantz aufgebauten neuen Alt-Stadt Erlang, Joh. Christoph Homann Geometrice delineavit A. 1721 ; edirt von Ioh. Bapt. Homann keiserl. Geogr. It was published by Johann Baptist Homann in 1721. Scale [ca. 1:8,200]. Covers Erlangen, Germany. Map in German.The image inside the map neatline is georeferenced to the surface of the earth and fit to the Deutsches Hauptdreiecksnetz (DHDN) 3-degree Gauss-Kruger Zone 4 coordinate system. 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, index maps, legends, or other information associated with the principal map. This map shows features such as roads, drainage, built-up areas and selected buildings, fortifications, ground cover, and more. Relief shown with hachures. Includes also index and 7 views of the city.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.