22 research outputs found
Europe's confused transmutation: the realignment of moral cartography in Juan de la Cosa's Mappa Mundi (1500)
Following the voyages of Christopher Columbus, John Cabot, Alonso de Ojeda and Amerigo Vespucci in the last decade of the fifteenth century, the New World of the Americas entered the cartographic and moral consciousness of Europe. In the 1500 mappa mundi of Juan de la Cosa, navigator and map-maker, we see Europe as a hybrid moral entity, a transitional blend of the medieval and the modern at the crossroads between two mappings of Europe. This paper argues that the Juan De la Cosa map represents a blurred transition between map-making traditions and a mixed moral rhetoric of European identity. The De la Cosa map operates across two sets of imagined axes: held horizontally, the map is set to a Ptolemaic grid with Europe straddling the Prime Meridian, and yet when held vertically it presents a medieval moral continuum in which the Americas occupy an ascendant position, a verdant new Jerusalem in contrast to the Babylon of the Old World. Europe is both drawn to the centre of a new world order, and also pushed to the moral margins in an echo of the medieval mappa mundi still imperfectly resolved
PDRs4All II: JWST's NIR and MIR imaging view of the Orion Nebula
The JWST has captured the most detailed and sharpest infrared images ever
taken of the inner region of the Orion Nebula, the nearest massive star
formation region, and a prototypical highly irradiated dense photo-dissociation
region (PDR). We investigate the fundamental interaction of far-ultraviolet
photons with molecular clouds. The transitions across the ionization front
(IF), dissociation front (DF), and the molecular cloud are studied at
high-angular resolution. These transitions are relevant to understanding the
effects of radiative feedback from massive stars and the dominant physical and
chemical processes that lead to the IR emission that JWST will detect in many
Galactic and extragalactic environments. Due to the proximity of the Orion
Nebula and the unprecedented angular resolution of JWST, these data reveal that
the molecular cloud borders are hyper structured at small angular scales of
0.1-1" (0.0002-0.002 pc or 40-400 au at 414 pc). A diverse set of features are
observed such as ridges, waves, globules and photoevaporated protoplanetary
disks. At the PDR atomic to molecular transition, several bright features are
detected that are associated with the highly irradiated surroundings of the
dense molecular condensations and embedded young star. Toward the Orion Bar
PDR, a highly sculpted interface is detected with sharp edges and density
increases near the IF and DF. This was predicted by previous modeling studies,
but the fronts were unresolved in most tracers. A complex, structured, and
folded DF surface was traced by the H2 lines. This dataset was used to revisit
the commonly adopted 2D PDR structure of the Orion Bar. JWST provides us with a
complete view of the PDR, all the way from the PDR edge to the substructured
dense region, and this allowed us to determine, in detail, where the emission
of the atomic and molecular lines, aromatic bands, and dust originate
PDRs4All III: JWST's NIR spectroscopic view of the Orion Bar
(Abridged) We investigate the impact of radiative feedback from massive stars
on their natal cloud and focus on the transition from the HII region to the
atomic PDR (crossing the ionisation front (IF)), and the subsequent transition
to the molecular PDR (crossing the dissociation front (DF)). We use
high-resolution near-IR integral field spectroscopic data from NIRSpec on JWST
to observe the Orion Bar PDR as part of the PDRs4All JWST Early Release Science
Program. The NIRSpec data reveal a forest of lines including, but not limited
to, HeI, HI, and CI recombination lines, ionic lines, OI and NI fluorescence
lines, Aromatic Infrared Bands (AIBs including aromatic CH, aliphatic CH, and
their CD counterparts), CO2 ice, pure rotational and ro-vibrational lines from
H2, and ro-vibrational lines HD, CO, and CH+, most of them detected for the
first time towards a PDR. Their spatial distribution resolves the H and He
ionisation structure in the Huygens region, gives insight into the geometry of
the Bar, and confirms the large-scale stratification of PDRs. We observe
numerous smaller scale structures whose typical size decreases with distance
from Ori C and IR lines from CI, if solely arising from radiative recombination
and cascade, reveal very high gas temperatures consistent with the hot
irradiated surface of small-scale dense clumps deep inside the PDR. The H2
lines reveal multiple, prominent filaments which exhibit different
characteristics. This leaves the impression of a "terraced" transition from the
predominantly atomic surface region to the CO-rich molecular zone deeper in.
This study showcases the discovery space created by JWST to further our
understanding of the impact radiation from young stars has on their natal
molecular cloud and proto-planetary disk, which touches on star- and planet
formation as well as galaxy evolution.Comment: 52 pages, 30 figures, submitted to A&
Cartografía militar española de Indias
Origen y naturaleza de la cartografía militar. Sus comienzos en las indias occidentales. desarrollo posterior en el siglo cviii. el cuerpo de ingenieros militares. Ordenanzas cartográficas de 1718, 1768 y 1803. Métodos de levantamiento e instrumentos empleados. El cuerpo de estado mayor del ejercito: sus misiones cartográficas y actuación en cuba, puerto rico y filipinas. épocas distintas en la formación de la cartografía militar en América y sus características. Necesidad de un detenido estudio de aquella cartografía para determinar su evolución, identificar autores anónimos y datar documentos sin fecha. Breve relación de autores mas significativos. (a