The Origin and Optical Depth of Ionizing Radiation in the "Green Pea" Galaxies

Although Lyman continuum (LyC) radiation from star-forming galaxies likely drove the reionization of the Universe, observations of star-forming galaxies at low redshift generally indicate low LyC escape fractions. However, the extreme [O III]/[O II] ratios of the z=0.1-0.3 Green Pea galaxies may be due to high escape fractions of ionizing radiation. To analyze the LyC optical depths and ionizing sources of these rare, compact starbursts, we compare nebular photoionization and stellar population models with observed emission lines in the Peas' SDSS spectra. We focus on the six most extreme Green Peas, the galaxies with the highest [O III]/[O II] ratios and the best candidates for escaping ionizing radiation. The Balmer line equivalent widths and He I {\lambda}3819 emission in the extreme Peas support young ages of 3-5 Myr, and He II {\lambda}4686 emission in five extreme Peas signals the presence of hard ionizing sources. Ionization by active galactic nuclei or high-mass X-ray binaries is inconsistent with the Peas' line ratios and ages. Although stacked spectra reveal no Wolf-Rayet (WR) features, we tentatively detect WR features in the SDSS spectra of three extreme Peas. Based on the Peas' ages and line ratios, we find that WR stars, chemically homogeneous O stars, or shocks could produce the observed He II emission. If hot stars are responsible, the Peas' optical depths are ambiguous. However, accounting for emission from shocks lowers the inferred optical depth and suggests that the Peas may be optically thin. The Peas' ages likely optimize the escape of Lyman-continuum radiation; they are old enough for supernovae and stellar winds to reshape the interstellar medium, but young enough to possess large numbers of UV-luminous O or WR stars.Comment: 27 pages, 14 figures, Submitted to ApJ (revised version after referee report

Haro 11: Where is the Lyman continuum source?

Identifying the mechanism by which high energy Lyman continuum (LyC) photons escaped from early galaxies is one of the most pressing questions in cosmic evolution. Haro 11 is the best known local LyC leaking galaxy, providing an important opportunity to test our understanding of LyC escape. The observed LyC emission in this galaxy presumably originates from one of the three bright, photoionizing knots known as A, B, and C. It is known that Knot C has strong Ly$\alpha$ emission, and Knot B hosts an unusually bright ultraluminous X-ray source, which may be a low-luminosity AGN. To clarify the LyC source, we carry out ionization-parameter mapping (IPM) by obtaining narrow-band imaging from the Hubble Space Telescope WFC3 and ACS cameras to construct spatially resolved ratio maps of [OIII]/[OII] emission from the galaxy. IPM traces the ionization structure of the interstellar medium and allows us to identify optically thin regions. To optimize the continuum subtraction, we introduce a new method for determining the best continuum scale factor derived from the mode of the continuum-subtracted, image flux distribution. We find no conclusive evidence of LyC escape from Knots B or C, but instead, we identify a high-ionization region extending over at least 1 kpc from Knot A. Knot A shows evidence of an extremely young age ($\lesssim 1$ Myr), perhaps containing very massive stars ($>100$ M$_\odot$). It is weak in Ly$\alpha$, so if it is confirmed as the LyC source, our results imply that LyC emission may be independent of Ly$\alpha$ emission.Comment: 12 pages, 6 Figures, Submitted to Ap

An Approach to the (Non)Equivalence of Legal Terms in Bilingual Polish-Spanish and Spanish-Polish Dictionaries

The new European legal context prompted the creation of an original terminology within the existing Polish and Spanish legal language. As far as legal translation and the methods used in the specialized translation are concerned, it is crucial to remember that the law as science and a culture element of each nation has its own language. One of the most effective and essential tools in the work of each legal translator are bilingual dictionaries. Notwithstanding, lexicographical resources, which should support the translator, often lack adequate equivalent. That is why, conducting studies based on the Polish-Spanish and Spanish-Polish bilingual dictionaries in the context of linguistic analysis of lexical equivalents seems reasonable. The article approaches the phenomenon of equivalence or the lack of equivalence of selected lexical units in the legal field in order to demonstrate existing tools within general or specialized dictionaries available to – in our particular case – Polish translators whose working language is Spanish.The new European legal context prompted the creation of an original terminology within the existing Polish and Spanish legal language. As far as legal translation and the methods used in the specialized translation are concerned, it is crucial to remember that the law as science and a culture element of each nation has its own language. One of the most effective and essential tools in the work of each legal translator are bilingual dictionaries. Notwithstanding, lexicographical resources, which should support the translator, often lack adequate equivalent. That is why, conducting studies based on the Polish-Spanish and Spanish-Polish bilingual dictionaries in the context of linguistic analysis of lexical equivalents seems reasonable. The article approaches the phenomenon of equivalence or the lack of equivalence of selected lexical units in the legal field in order to demonstrate existing tools within general or specialized dictionaries available to – in our particular case – Polish translators whose working language is Spanish

Architecture, War and Genocide: Military Goals and the Development of SS Concentration Camp Architecture

World War II is a defining war for understanding modern history not only because of its place in 20th-century geopolitics but particularly because of the scale of warfare and new level of brutality. As is well known, central to the Nazi military campaign in the East were the ideological goals of state leaders to expand the land available for 'German' settlement and, concomitantly, to rid that land of those designated undesirable, above all the European Jews. The architectural remnants of the SS concentration camps have become emblematic for the experience of victims in this campaign as well as the extremes of Nazi policy. And yet in spite of their status as some of the most infamous construction in the modern period, relatively few architectural historians take up the concentration camps in their analysis of German architecture. Further, the minority of architectural historians who have analyzed the camps tend to focus on one site rather than the system as a whole and naturally concern themselves with the experience of the victims rather than the perpetrator's interests and view of architecture. Deborah Dwork and Robert Jan van Pelt's important work on Auschwitz is an exception to many of these trends. Still, in terms of the military campaigns going on in the East, even they tend to see Auschwitz as an ideological site that developed over time parallel to the military campaigns rather than as integral to them. In this account, the concentration camps and the waging of war produce simultaneous if related goals. This paper argues against the isolation of the concentration camps from the war by taking a broader view of the construction of SS concentration camps, analyzing their typological development and use of specific architectural and spatial traditions. In particular, it argues that the imperial goals of the war as emphasized in the political economic goals of the state are integral for helping to explain the scale and architectural choices made at Auschwitz and other concentration camps in the SS universe. In so doing, I look not only at the important parts of the camps that were sites of massive oppression but also at those sites built for the SS themselves, analyzing administrative and visual evidence concerning their own goals and their own construction. With this focus, the intersection of racist ideological goals and the military political economy of empire are manifest. Refocusing on the architecture of the concentration camps helps us to explain the implementation of warfare, its radicalization and its role in an imperial drive of unifying diverse ideological and political agendas.Conference co-organized by the Institute of Fine Arts; Canadian Centre for Architecture, Montreal; and Princeton University's School of Architecture

MICROLAN file transfer program for microprocessors

The age of automation has established its foothold in today's society. Computerization now affects almost everyone's job, and sharing of information is vital to successful job performance. Manual transfer of information is inefficient and prone to error, so another means is needed. One option is computer networking. Both Local Area Networks and long-haul networks presently exist, but they are either very expensive or hardware dependent. It would normally require a long lead time and high costs for the military to acquire an information transfer system. To provide a readily available, low-cost file transfer system, the authors developed an assembly language program named MICROLAN, which is written to work with three of the main microcomputer operating systems (CP/M-80, CP/M-86, and IIS. DOS) and to take advantage of RS232 technology. MICROLAN was tested successfully for file transfer at up to 4800 baud, and suggestions have been included as to possible uses for MICROLAN in the military environment. Additionally, possible methods for upgrading MICROLAN are also included.Lieutenant, United States NavyCaptain, United States Air ForceApproved for public release; distribution is unlimited

Neutral Gas Properties and Lyα\alpha Escape in Extreme Green Pea Galaxies

Mechanisms regulating the escape of Ly$\alpha$ photons and ionizing radiation remain poorly understood. To study these processes we analyze VLA 21cm observations of one Green Pea (GP), J160810+352809 (hereafter J1608), and HST COS spectra of 17 GP galaxies at $z<0.2$. All are highly ionized: J1608 has the highest [O III] $\lambda5007$/[O II] $\lambda3727$ for star-forming galaxies in SDSS, and the 17 GPs have [O III]/[O II] $\geq6.6$. We set an upper limit on J1608's HI mass of $\log M_{HI}/M_\odot=8.4$, near or below average compared to similar mass dwarf galaxies. In the COS sample, eight GPs show Ly$\alpha$ absorption components, six of which also have Ly$\alpha$ emission. The HI column densities derived from Ly$\alpha$ absorption are high, $\log N_{HI}/$cm$^{-2}=19-21$, well above the LyC optically thick limit. Using low-ionization absorption lines, we measure covering fractions (f_{\mbox{cov}}) of $0.1-1$, and find that f_{\mbox{cov}} strongly anti-correlates with Ly$\alpha$ escape fraction. Low covering fractions may facilitate Ly$\alpha$ and LyC escape through dense neutral regions. GPs with f_{\mbox{cov}}\sim1 all have low neutral gas velocities, while GPs with lower f_{\mbox{cov}}=0.2-0.6 have a larger range of velocities. Conventional mechanical feedback may help establish low f_{\mbox{cov}} in some cases, whereas other processes may be important for GPs with low velocities. Finally, we compare f_{\mbox{cov}} with proposed indicators of LyC escape. Ionizing photon escape likely depends on a combination of neutral gas geometry and kinematics, complicating the use of emission-line diagnostics for identifying LyC emitters.Comment: 21 pages, 11 figures, accepted for publication in Ap

Green Pea Galaxies Reveal Secrets of Lyα\alpha Escape

We analyze archival Ly$\alpha$ spectra of 12 "Green Pea" galaxies observed with the Hubble Space Telescope, model their Ly$\alpha$ profiles with radiative transfer models, and explore the dependence of Ly$\alpha$ escape fraction on various properties. Green Pea galaxies are nearby compact starburst galaxies with [OIII]$\lambda$5007 equivalent widths of hundreds of \AA. All 12 Green Pea galaxies in our sample show Ly$\alpha$ lines in emission, with a Ly$\alpha$ equivalent width distribution similar to high redshift Ly$\alpha$ emitters. Combining the optical and UV spectra of Green Pea galaxies, we estimate their Ly$\alpha$ escape fractions and find correlations between Ly$\alpha$ escape fraction and kinematic features of Ly$\alpha$ profiles. The escape fraction of Ly$\alpha$ in these galaxies ranges from 1.4% to 67%. We also find that the Ly$\alpha$ escape fraction depends strongly on metallicity and moderately on dust extinction. We compare their high-quality Ly$\alpha$ profiles with single HI shell radiative transfer models and find that the Ly$\alpha$ escape fraction anti-correlates with the derived HI column densities. Single shell models fit most Ly$\alpha$ profiles well, but not the ones with highest escape fractions of Ly$\alpha$. Our results suggest that low HI column density and low metallicity are essential for Ly$\alpha$ escape, and make a galaxy a Ly$\alpha$ emitter.Comment: 9 figures, ApJ accepte