A total of 193 IAU Circulars were issued in 2005 --- remarkably similar to the number of 198 IAUCs published in 2004, considering that 243 CBETs were also issued in 2005 (compared to only 46 CBETs in 2004). As has been the case in recent years, the most common topics covered were supernovae, with 29 percent of the IAUC titles dealing with supernova discoveries and another 14 percent with follow-up information on already announced discoveries. Comets remain a prominent part of IAUC announcements, with 24 percent of the year's titles pertaining to discoveries or recoveries of comets, and another 12 percent dealing with follow-up information on comets. Around 11 percent of the year's IAUC titles dealt with Galactic novae and variable stars, including the ten new Galactic novae found in 2005. The brightest Galactic nova in 2005 was V5116 Sgr, reaching visual mag approximately 7.5 around July 5.
Numerous items during the year pertained to novae in other galaxies, including one in each of the Magellanic Clouds. As noted in last year's report, a new CBAT webpage was established to handle novae in M31, and the table therein was expanded considerably in 2005. Also during 2004, numerous separately titled IAUC items were published concerning other unusual transients observed at visible, radio, and high-energy wavelengths. A bright infrared outburst of the nucleus of Arp 299 was one such report. In addition to spectroscopic reports of new supernovae, other topics having reports published primarily in 2005 on CBETs and not on IAUCs include numerous reports of meteor activity and binary-nature detection for minor planets.
The Central Bureau issued 402 new designations for supernova discoveries announced during 2005, including 45 designations for belated 2004 discovery reports. The brightest supernova of the year, the type-II event in NGC 4945 that was designated 2005af, was found by amateur astronomers C. Jacques and E. Pimentel in Belo Horizonte, Brazil, and reached visual mag around 12.5 in mid-February. The type-Ia supernova 2005df in NGC 1559 was found visually by the well-known Australian supernova discoverer R. Evans at mag 13.8 in early August. Some 250 of the supernovae were spectroscopically typed as Ia (or suspected Ia) events, 38 were type-Ib or type-Ic supernovae (or so suspected), 84 were type-II (or suspected type-II) events, and 33 were not classified. SN 2005cs in M51 was around mag 14 in late June, and a 24th-magnitude supposed red supergiant was reported on the IAUCs as being the likely progenitor.
Many faint supernova discoveries were reported in individual reports during the year by high-redshift surveys, and these were announced on CBETs, with brief summaries following on the printed IAUCs. The Sloan Digital Sky Survey detected 182 new supernovae in 2005 (45 percent of all the supernovae designated during the year), but only 26 of them were brighter than mag 20 at discovery. Among supernovae brighter than 20th magnitude, the Lick Observatory Supernova Survey again dominated in 2005, with 80 discoveries. Fully 92 supernovae (nearly a quarter of the total found in 2005) were discovered or co-discovered by amateur astronomers during the year --- a third more than in 2004 --- led by Tim Puckett's search with 37 discoveries.
The ongoing discussion by the CBAT Director with the 'supernova community' (see the 2004 annual report) has continued, in which plans were drawn up for starting an e-mail list for rapid reporting of discoveries and follow-up information, intended to be posted also on a webpage --- the idea being that only registrants who are bona fide members of the international supernova community (including amateurs who discover supernovae) can post, but anybody can access the information. The CBAT Director and Assistant Director also participated in a Tucson conference in early December organized by the Virtual Observatory Event group to discuss ways of getting discoveries (especially of supernovae) properly reported and announced through the expanding VO network.
The continuing close collaboration of the CBAT with the Minor Planet Center resulted in near-simultaneous announcements on IAU Circulars and Minor Planet Electronic Circulars of most of the professional-survey comets, many of which are initially reported as asteroidal but found to show cometary appearance elsewhere by follow-up observers (many of whom again are amateurs) who monitor the MPC's 'Near-Earth-Object Confirmation' webpage. The annual Edgar Wilson Award for comet discovery by amateurs was also announced by the Central Bureau in late June, with only two recipients in 2005. Fifty-three ground-based comet discoveries were announced on IAUCs during the year (led by the sixteen found by Steve Larson's surveys at the University of Arizona), plus scores of near-sun comets only seen with the SOHO-spacecraft coronagraphs (beginning in April 2005, the IAUCs have published extended physical information for all the newly announced SOHO comets). Comet 9P/Tempel received much attention in CBAT publications during the year because of its encounter with the 'Deep Impact' spacecraft in early July.
Dominating solar-system news during the year, for which several items were published on IAUCs, were the discoveries of three unexpectedly bright (mag 17-18) transneptunian objects, two of which (2003 UB313 and 2003 EL61) appear to have sizes that exceed the diameter of Pluto, with both also possessing satellites. Thirteen new satellites of Saturn, two new satellites of Pluto, and two new rings of Uranus were announced on IAUCs in 2005, along with the assignment of new designations and names for Saturn XXXI-XXXIV, Jupiter XXXIX-XLVIII, and Uranus XXII-XXVII. Several CBAT items were published during the year regarding the minor planet (99942) Apophis = 2004 MN4, which will make an approach to within about 6 earth radii on 2029 Apr. 13.9 UT and just possibly an even closer approach in 2036.
The CBAT has continued its a notable presence on the World Wide Web, with those Circulars and CBETs older than about one year being posted freely. The number of paid subscribers to the printed edition of the IAU Circulars continued to fall, from 158 at the end of 2004 to 146 at the end of 2005. However, the subscriptions to the printed IAUCs do pay for the cost of printing and mailing, and there clearly is a continued interest in printing the IAUCs --- both from the subscribers and from contributors who perceive a certain prestige for a publication with a very long history in print, despite the simultaneous online presence. In addition, there were 15 free (complimentary or exchange) subscriptions to the printed IAUCs at the end of 2005. The printed IAUCs go to 60 addresses within North America and 101 outside of North America. The number of subscribers to the Computer Service (shared by the CBAT with the MPC, and which includes web access to all CBAT publications plus eligibility for e-mail delivery) remained very stable, at around 470.
Unfortunately, the subscription and line-charge income is no longer sufficient to sustain fully the salary of the current CBAT Director, as it has done since 1980, together with secretarial help. While there are likely sufficient funds through subscriptions and line charges to pay the Director's and secretary's salaries into 2007, a worrisome situation has developed regarding the financial relationship of the Minor Planet Center with the CBAT; while the two bureaus have co-existed financially since 1978, problems with MPC funding may necessitate separation of the two financially to prevent a collapse of the CBAT. Therefore, the Director has been actively seeking alternate sources of income to maintain the presence of the CBAT at the Harvard-Smithsonian Center for Astrophysics, including the submission of a proposal in November 2005 to the U.S. National Science Foundation for a 5-year grant to cover the Director's salary. By the time of the Prague meeting in August 2006, it is hoped that funding will have been obtained to keep the CBAT operating at the CfA.
Assistant Director G. V. Williams has continued to serve as joint MPC/CBAT webmaster (and has been responsible for the Web CS dissemination of the IAUCs). All of the year's Circulars were prepared by the undersigned, with very helpful editorial backup by Director Emeritus B. G. Marsden, who prepared some CBETs during the Director's absence from Cambridge during the year (and helped to proofread and referee many IAUCs prior to issuance and to discuss many CBAT matters from his decades of experience as CBAT Director).
Numerous referees worldwide, especially some who are Commission 6 members, are also to be thanked for their great help with many items published on Circulars in 2005, continuing the long practice of the IAUCs being a refereed publication. Correspondence with scientists, the general public, and the news media occupies much of the Director's time, with thousands of e-mails and many phone calls relating to CBAT science arriving each year. At SAO, Muazzez Lohmiller has continued to handle the accounts, addressing of envelopes, and other administrative matters. Dan Wooldridge continues, as he has for years, with the fine printing of the IAUC cards.
Daniel W. E. Green
Director of the Bureau