Question: Who currently publishes the American science fiction magazine in which Impossible Dreams by Tim Pratt was first published?
Context: A fantasy fiction magazine or fantasy magazine is a magazine which publishes primarily fantasy fiction.  Not generally included in the category are magazines for children with stories about such characters as Santa Claus.  Also not included are adult magazines about sexual fantasy.  Many fantasy magazines, in addition to fiction, have other features such as art, cartoons, reviews, or letters from readers.  Some fantasy magazines also publish science fiction and horror fiction, so that here is not always a clear distinction between a fantasy magazine and a science fiction magazine.  For example, "Fantastic" magazine published almost exclusively science fiction for much of its run. Fantasy Magazine was an American online fantasy and science fiction magazine.  It was launched as a print edition at the 2005 World Fantasy Convention in Madison, Wisconsin.  It continued in this format for six more issues, but in mid-October 2007, it moved online, with daily content, and spun off an original anthology, titled "Fantasy".  The magazine has published, in the past, stories by Peter S. Beagle, Jeffrey Ford, Theodora Goss, Caitlin Kiernan, Joe R. Lansdale, Nick Mamatas, Tim Pratt, Cat Rambo, Ekaterina Sedia, Catherynne M. Valente, Jeff VanderMeer, and more. Vargo Statten Science Fiction Magazine (later Vargo Statten British Science Fiction Magazine, The British Science Fiction Magazine and The British Space Fiction Magazine) was a British science fiction magazine which published nineteen issues between 1954 and 1956.  It was initially published by Scion Press, with control passing to a successor company, Scion Distributors, after Scion went bankrupt in early 1954.  At the end of 1954, as part payment for a debt, Scion Distributors handed control of the magazine to Dragon Press, who continued it for another twelve issues.  E.C. Tubb and John Russell Fearn were regular contributors, and Kenneth Bulmer also published several stories in the magazine.  Barrington Bayley's first published story, "Combat's End", appeared in May 1954.  The editor was initially Alistair Paterson, but after seven issues Fearn took the helm: "Vargo Statten" was one of Fearn's aliases, and the magazine's title had been chosen because of his popularity.  Neither Paterson nor Fearn had enough of a budget to attract good quality submissions, and a printing strike in 1956 brought an end to the magazine's life. Authentic Science Fiction was a British science fiction magazine published in the 1950s that ran for 85 issues under three editors: Gordon Landsborough, H.J. Campbell, and E.C. Tubb.  The magazine was published by Hamilton and Co., and began in 1951 as a series of novels appearing every two weeks; by the summer it became a monthly magazine, with readers' letters and an editorial page, though fiction content was still restricted to a single novel.  In 1952 short fiction began to appear alongside the novels, and within two more years it completed the transformation into a science fiction magazine. Science Fiction Quarterly was an American pulp science fiction magazine that was published from 1940 to 1943 and again from 1951 to 1958.  Charles Hornig served as editor for the first two issues; Robert A. W. Lowndes edited the remainder.  "Science Fiction Quarterly" was launched by publisher Louis Silberkleit during a boom in science fiction magazines at the end of the 1930s.  Silberkleit launched two other science fiction titles ("Science Fiction" and "Future Fiction) "at about the same time: all three ceased publication before the end of World War II, falling prey to slow sales and paper shortages.  In 1950 and 1951, as the market improved, Silberkleit relaunched "Future Fiction" and "Science Fiction Quarterly".  By the time "Science Fiction Quarterly" ceased publication in 1958, it was the last surviving science fiction pulp. Impossible Dreams is a science fiction short story written in 2006 by Tim Pratt.  It was first published in "Asimov's Science Fiction" in 2006, and subsequently republished in Pratt's 2007 collection "Hart & Boot & Other Stories", and in the 2012 anthology "Other Worlds Than These". Asimov's Science Fiction (ISSN 1065-2698) is an American science fiction magazine which publishes science fiction and fantasy named after science fiction author Isaac Asimov.  It is currently published by Penny Publications.  From January 2017, the publication frequency is bimonthly (six issues per year). Lightspeed is an American online fantasy and science fiction magazine edited and published by John Joseph Adams.  The first issue was published in June 2010 and it has maintained a regular monthly schedule since.  The magazine currently publishes four original stories and four reprints in every issue, in addition to interviews with the authors and other nonfiction.  All of the content published in each issue is available for purchase as an ebook and for free on the magazine's website.  "Lightspeed" also makes selected stories available as a free podcast, produced by Audie Award-winning editor Stefan Rudnicki. Wonder Stories was an early American science fiction magazine which was published under several titles from 1929 to 1955.  It was founded by Hugo Gernsback in 1929 after he had lost control of his first science fiction magazine, "Amazing Stories", when his media company Experimenter Publishing went bankrupt.  Within a few months of the bankruptcy, Gernsback launched three new magazines: "Air Wonder Stories", "Science Wonder Stories" and "Science Wonder Quarterly". The Magazine of Fantasy & Science Fiction (usually referred to as F&SF) is a U.S. fantasy and science fiction magazine first published in 1949 by Fantasy House, a subsidiary of Lawrence Spivak's Mercury Press.  Editors Anthony Boucher and J. Francis McComas had approached Spivak in the mid-1940s about creating a fantasy companion to Spivak's existing mystery title, "Ellery Queen's Mystery Magazine".  The first issue was titled "The Magazine of Fantasy", but the decision was quickly made to include science fiction as well as fantasy, and the title was changed correspondingly with the second issue.  "F&SF" was quite different in presentation from the existing science fiction magazines of the day, most of which were in pulp format: it had no interior illustrations, no letter column, and text in a single column format, which in the opinion of science fiction historian Mike Ashley "set "F&SF" apart, giving it the air and authority of a superior magazine".
Answer: Penny Publications