The Voigt and complex error function: Huml\'i\v{c}ek's rational approximation generalized

Accurate yet efficient computation of the Voigt and complex error function is a challenge since decades in astrophysics and other areas of physics. Rational approximations have attracted considerable attention and are used in many codes, often in combination with other techniques. The 12-term code "cpf12" of Huml\'i\v{c}ek (1979) achieves an accuracy of five to six significant digits throughout the entire complex plane. Here we generalize this algorithm to a larger (even) number of terms. The $n=16$ approximation has a relative accuracy better than $10^{-5}$ for almost the entire complex plane except for very small imaginary values of the argument even without the correction term required for the cpf12 algorithm. With 20 terms the accuracy is better than $10^{-6}$. In addition to the accuracy assessment we discuss methods for optimization and propose a combination of the 16-term approximation with the asymptotic approximation of Huml\'i\v{c}ek (1982) for high efficiency.Comment: 9 pages, 5 figure

Hello, Readers!

My name is Alexa Schreier and I am serving as the Barbara Holley Intern for the next year (through Academic Year 2015/2016)! As the Holley Intern I will be moving around between the four main departments at Musselman Library, which includes Special Collections & Archives, Tech Services, User Services, and Research and Instruction. [excerpt

The Art of Processing a Collection

One of the most astounding things about Special Collections and Archives is that there is no necessarily right or wrong way to process a collection. If you have the same questions as I did when I first started, you may be wondering what exactly processing a collection means. Coming from a background of working in libraries, there has always been a right and wrong order, and most often than not the right way includes being alphabetical and chronological. However, that’s not always the case in Special Collections. What I’ve learned so far is that effectively processing a collection means to organize any array of papers, letters, artifacts, etc., in a manner that will make it easiest for researchers to either know if the collection could be useful to them, or quickly identify which parts of a collection they’re interested in. [excerpt

MS – 185: Dance Cards of Ruth Sachs ‘26

The collection consists primarily of Dance Cards from Gettysburg College from 1922-1927. The dance cards included largely feature events hosted by either the Beta Lambda (Delta Gamma) Sorority or Delta Kappa Sigma Fraternity. However other events include the Sophomore Banquet, Junior Prom, Leap Year Dance, Co-Ed Dance, and Albright College’s Junior Prom. In addition to the 27 dance cards, the collection includes an event program and table place cards with Ruth’s name. Special Collections and College Archives Finding Aids are discovery tools used to describe and provide access to our holdings. Finding aids include historical and biographical information about each collection in addition to inventories of their content. More information about our collections can be found on our website https://www.gettysburg.edu/special-collections/collections/.https://cupola.gettysburg.edu/findingaidsall/1206/thumbnail.jp

White paper on science operations

Major changes are taking place in the way astronomy gets done. There are continuing advances in observational capabilities across the frequency spectrum, involving both ground-based and space-based facilities. There is also very rapid evolution of relevant computing and data management technologies. However, although the new technologies are filtering in to the astronomy community, and astronomers are looking at their computing needs in new ways, there is little coordination or coherent policy. Furthermore, although there is great awareness of the evolving technologies in the arena of operations, much of the existing operations infrastructure is ill-suited to take advantage of them. Astronomy, especially space astronomy, has often been at the cutting edge of computer use in data reduction and image analysis, but has been somewhat removed from advanced applications in operations, which have tended to be implemented by industry rather than by the end-user scientists. The purpose of this paper is threefold. First, we briefly review the background and general status of astronomy-related computing. Second, we make recommendations in three areas: data analysis; operations (directed primarily to NASA-related activities); and issues of management and policy, believing that these must be addressed to enable technological progress and to proceed through the next decade. Finally, we recommend specific NASA-related work as part of the Astrotech-21 plans, to enable better science operations in the operations of the Great Observatories and in the lunar outpost era

Einstein observations of active galaxies and quasars

The radio galaxies Centaurus A and Signus B are discussed. In both these sources, a comparison of the radio and imaged X-ray flux is allowed for the measurement of the magnetic fields. Einstein observations of quasars are discussed. The number of known X-ray emitting QSO's was increased from 3 to 22 and the distances where these QSO's were seen to correspond to an age of 15 billion years. It was shown that these quasars contributed significantly to the X-ray background