Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.naic.edu/~rminchin/press/VIRGOHI21_press_release.pdf Дата изменения: Sat Jan 7 04:07:54 2006 Дата индексирования: Sat Dec 22 04:32:07 2007 Кодировка:

New evidence for a Dark Galaxy FOR RELEASE: Thursday January 12, 2006 9:20 AM EST New evidence that VIRGOHI 21, a mysterious cloud of hydrogen light-years from the Ear th, is a D ark Galaxy was pres ented today Society meeting in Washington, D . C . by an international team National Science Foundation's Arecibo Observatory and from C Kingdom. in the Virgo Cluster 50 million at the American Astronomical led by as tronomers from the ardiff U niversity in the U nited

The new observations, made with the Westerbork Synthesis Radio Telescope in the Netherlands , show that the hydrogen gas in VIRGOH I 21 appears to be rotating, implying a dark galaxy with over ten billion times the mass of the Sun. Only one percent of this mass has been detected as neutral hydrogen ­ the rest appears to be dark matter. But this is not all that the new data reveal. The r esults may also solve a long-standing puzzle about another nearby galaxy. NGC 4254 is lopsided, with one spiral arm much larger than the rest. This is usually caused by the influence of a companion galaxy, but none could be found until now ­ the team thinks VIRGOHI 21 is the culprit. Dr. Rober t Minchin of Arecibo Observatory says; "The Dark Galaxy theory explains both the obser vations of VIRGOH I 21 and the mystery of NGC 4254." The team have looked at many other possible explanations , but have found that only the Dark Galaxy theory can explain all of the observations . As Professor Mike Disney of Cardiff University puts it, "The new observations make it even harder to escape the conclusion that VIRGOHI 21 is a Dark Galaxy ." The team hope that this will be the first of many such finds . "We're going to be searching for more Dark Galaxies with the new ALFA ins trument at Arecibo Observatory," explains Dr. Jon Davies of Cardiff University . " We hope to find many more over the next few years ­ this is a very exciting time!" NOTES FOR ED ITOR S: 1. The following images will available on the web in a var iety of s izes up to 6 inches at 300 dpi at http://w ww.naic.edu/~rminchin/press as soon as the embargo expires on Thursday January 12, 2006 9:20 AM EST CAPTION : Dark Galaxy VIR GOH I 21 has no s tarlight but radio waves from neutral hydrogen betray its existence. The contours superimposed on this optical image indicate how muc h gas was detected. This material was presented to the American Astronomical Society meeting in W ashington, D. C . on January 12, 2006. CRED IT: Ar ecibo Observatory / Cardiff U niversity / Isaac Newton Telescope / Wes terbork Synthesis Radio Teles cope. CAPTION : Neutral hydrogen gas streams between NGC 4254 (top left) and the Dark Galaxy VIR GOH 1 21 (center right) in this image made from radio telescope observations at a w avelength of 21 centimeters. This interac tion could explain the mystery of NGC 4254's peculiar lopsided shape. To the bottom left, a ring of gas can be seen around the galaxy NGC 4262. This material was presented to the Amer ican As tronomical Society meeting in Washington, D . C . on January 12, 2006.


CRED IT: Arecibo Observatory / Car diff U niversity / Westerbork Synthesis Radio Telescope. 2. Arecibo Observatory is part of the National Astronomy and Ionosphere Center , which is operated by Cornell University under a cooperative agreement with the National Science Foundation 3. The research was par tly funded by PPARC ­ the Par ticle Physics and As tronomy Research Council. PPARC is the UK's strategic science investment agency. It funds research, education and public understanding in four broad areas of science ­ par ticle physics, as tronomy, cosmology and space science. PPAR C is government funded and provides research grants and studentships to scientists in British universities, gives researchers access to world-class facilities and funds the UK membership of international bodies such as the European Organisation for N uclear Research, C ERN, the European Space Agency and the European Southern Observatory. It also contr ibutes money for the UK telescopes overseas on La Palma, Hawaii, Australia and in Chile, the UK Astronomy Technology Centr e at the Royal Observatory, Edinburgh and the MERLIN /VLBI National Facility . 4. The Wes terbork Synthesis Radio Telescope is operated by ASTRON (Netherlands Foundation for R esearch in Astronomy) w ith support fr om the Netherlands Foundation for Scientific R esearch (NW O). 5. The scientific paper "High resolution HI imaging of VIRGOH I 21 ­ a dark galaxy in the th th Virgo Clus ter" was presented on 12 January 2006 at the 207 meeting of the American Astronomical Society held in Washington, D. C. Authors are Robert Minchin ( Arecibo Observatory), Jon Davies , Mike Disney (Cardiff Univ ersity), Andy Marble, Chris Impey (Stew ard Observatory), Peter Boyce, Diego Garcia, Marco Grossi (Cardiff University), Chris Jordan (Jodrell Bank Observatory), Hugh Lang, Sarah Rober ts (Cardiff University) , Sabina Sabatini ( Osservatorio As tronomico di Roma), and Wim van Dr iel (Observatoire de Paris) 6. For an interview or fur ther technical comment please c ontact: Dr. Robert Minchin ­ Arec ibo Observatory Tel: ++1-787-878-2612 ext. 283 (contac t through AAS during the meeting) E-mail: r minchin@naic.edu Dr. Jon Davies ­ Cardiff University Tel: ++44-(0)29-20-875255 E-mail: jonathan.davies@ astro.cf.ac.uk