Are pulsars born with a hidden magnetic field?

The observation of several neutron stars in the centre of supernova remnants and with significantly lower values of the dipolar magnetic field than the average radio-pulsar population has motivated a lively debate about their formation and origin, with controversial interpretations. A possible explanation requires the slow rotation of the protoneutron star at birth, which is unable to amplify its magnetic field to typical pulsar levels. An alternative possibility, the hidden magnetic field scenario, considers the accretion of the fallback of the supernova debris on to the neutron star as responsible for the submergence (or screening) of the field and its apparently low value. In this paper, we study under which conditions the magnetic field of a neutron star can be buried into the crust due to an accreting, conducting fluid. For this purpose, we consider a spherically symmetric calculation in general relativity to estimate the balance between the incoming accretion flow and the magnetosphere. Our study analyses several models with different specific entropy, composition, and neutron star masses. The main conclusion of our work is that typical magnetic fields of a few times 1012 G can be buried by accreting only 10−3–10−2 M⊙, a relatively modest amount of mass. In view of this result, the central compact object scenario should not be considered unusual, and we predict that anomalously weak magnetic fields should be common in very young (< few kyr) neutron stars.

World Bathymetric Chart of the Oceans, 1899 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Bathymetrical chart of the oceans, showing the "deeps" according to Sir John Murray. It was published by the Royal Geographical Society in 1899. Scale [ca. 1:100,000,000]. The image inside the map neatline is georeferenced to the surface of the earth and fit to the 'World Gall Stereographic' projection with the central meridian at 20.00000 degrees west. 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 drainage, shoreline features, and more. Relief shown by hypsometric tints. Depths shown by gradient tints. This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection and the Harvard University Library as part of the Open Collections Program at Harvard University project: Organizing Our World: Sponsored Exploration and Scientific Discovery in the Modern Age. Maps selected for the project correspond to various expeditions and represent a range of regions, originators, ground condition dates, scales, and purposes.

Inca Empire, South America, 1873 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Ttahuantin-Suyu, or, the empire of the Yncas (except Quito and Chile) : in its four great divisions of Chincha-Suyu, Cunti-Suyu, Anti-Suyu, Colla-Suyu : with their tribes and ayllus or lineages, also the routes of the Ynca conquerors by Clements R. Markham ; Trel. Saunders Geogr. It was published for the Journal of the Royal Geographical Society in 1873. Scale [ca. 1:3,000,000]. Covers the territory of the former Inca Empire, South America.The image inside the map neatline is georeferenced to the surface of the earth and fit to the 'World Mercator' projection. 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 drainage, cities and other human settlements, Inca territories, routes of conquerors, shoreline features, and more. Relief shown by shading and hachures. Inset: An enlarged map of the cradle of the Ynca race.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection and the Harvard University Library as part of the Open Collections Program at Harvard University project: Organizing Our World: Sponsored Exploration and Scientific Discovery in the Modern Age. Maps selected for the project correspond to various expeditions and represent a range of regions, originators, ground condition dates, scales, and purposes.

Southeastern Australia, 1834 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Map of the discoveries in Australia : copied from the latest M.S. surveys in the Colonial Office, by permission dedicated to the Right Hon.ble Viscount Goderich, H.M. principal Secretary of State for the Colonies, and President of the Royal Geographical Society, by his Lordships obliged servant J. Arrowsmith. It was published by Pubd. by J. Arrowsmith, 35 Essex St., Strand in Feb. 15 1834. Scale [ca. 1:3,041,280]. Covers southeastern Australia with additions to the east of the Gulf of St. Vincent and Granite Island inserted in Encounter Bay.The image inside the map neatline is georeferenced to the surface of the earth and fit to the Asia South Lambert Conformal Conic 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 drainage, cities and other human settlements, territorial boundaries, shoreline features, and more. Relief shown by hachures and spot heights. Major explorations shown. Includes also notes and insets: The Colony of Western Australia ... -- [Map of Australia in Asia].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.

The Entomologist.

Title from cover.

The Wilbur and Orville Wright memorial lecture /

Caption title: The Wilbur and Orville Wright Memorial Lecture, Royal Aeronautical Society, London, England, December 13, 1984.

Joannes Matthaeus and his tract "De rerum inventoribus".

Pt. I, read before the Society Dec. 4, 1901; Pt. II, read Dec. 18, 1916.

The Geographical magazine.

Edited by Clements R. Markham.

Collectanea anglo-premonstratensia; documents drawn from the original register of the order, now in the Bodleian library, Oxford, and the transcript of another register in the British museum.

Mode of access: Internet.

The Geographical journal.

Includes the Proceedings of the Royal Geographical Society, formerly published separately.

Bibliotheca Indica.

Each number also has a distinctive title.

Transactions.

Proceedings of the society were published with the Transactions up to and including 1925 (except in 1st ser., v.4 3d ser., v.3-4; The Journal of proceedings from Jan. 1840 to Dec. 1846, though listed in content of 1st ser., v.4, was published separately) since 1926 the Proceedings have been published in a separate series, A detailed tabulated statement of the collation and dates of issue of the Proceedings published 1834 to 1895 may be found in an article in the Transactions for 1911, p. 750-767, entitled: On the dates of the publications of the Entomological society of London, by the Rev. G. Wheeler.

Prakritarupavatara; a Prakrit grammar based on the Valmikisutra by Simharaja, son of Samudrabandhayajvan,

Mode of access: Internet.