A total of 220 IAU Circulars were issued in 2003, down slightly from the 259 published in 2002 and the 229 published in 2001. Fifty-four preliminary 'Central Bureau Electronic Telegrams' (CBETs) were also issued in 2003, the first full year of implementation of this new feature that permits easier dissemination of urgent information than the TeXed Circulars (see last year's annual report). The use of CBETs especially helps when the Director is travelling; indeed, no IAUCs were issued during the Director's presence at the IAU General Assembly in Sydney in July, all information in that 2-week span being issued via CBETs (with full details published later on the formal IAUCs.

The most common topics covered again were supernovae (for which 316 designations for 2003 discoveries, 40 designations for 2002 discoveries, and 20 designations for earlier discoveries were announced on the year's Circulars, though three 2003 designations were found later to refer to normal foreground variable stars). Separately titled follow-up text on supernovae amounted to an additional 124 items during 2003. The brightest supernova of the year, SN 2003hv in NGC 1201 (found in early September at unfiltered CCD mag 12.5 by the Lick Observatory Supernova Search project), was surprisingly little-observed. Two visual discoveries by Robert Evans of Australia (SN 2003gd in M74 in June, and SN 2003gs in NGC 936 in July) reached mag 13-13.5. At the opposite end of the brightness range, a third of the supernovae receiving designations in 2003 were fainter than mag 20 at discovery. Though not the same subset, a full third of the objects given supernova designations in 2003 had no spectroscopic confirmation. Of the objects assigned some spectroscopic classification (some tentatively) during the year, 86 were categorized as type II, 153 as type Ia, and 27 as type Ib or Ic.

After much discussion by the CBAT Director with the 'supernova community' about what to do regarding the increasingly numerous spectroscopically unconfirmed faint supernovae (which many in the supernova community do not want given the formal supernova designations that bright or confirmed objects receive), a plan enthusiastically adopted by the new IAU Supernova Working Group (SNWG) in Sydney in July to establish a new CBAT/SNWG webpage for the posting of such problem objects apparently is still in the construction phase (hopefully to be implemented sometime in 2004); unconfirmed objects will then receive preliminary designations based on date of discovery, to be followed later by the standard, final supernova designation on IAUCs if and when confirmed.

Five galactic novae were reported on IAUCs during 2003, none evidently getting brighter than mag 7.7 (reached by DE Cir in October). Also, nineteen separately titled follow-up items to these novae appeared during the year. Twenty items were reported on IAUCs regarding novae in other galaxies, 32 items appeared concerning other unusual Galactic variables, and 41 items were published on the Circulars concerning non-optical transient astronomical objects. Late in the year, an unusual 3-magnitude outburst was reported of a quasar (IAUC 8258). GRB 030329 received considerable attention on the Circulars in 2003, its optical signature eventually given the supernova designation 2003dh (IAUC 8114).

Comets continued in 2003 to have a standard presence in the CBAT publications, with non-spacecraft discoveries and rediscoveries appearing under 49 titles, and follow-up information appearing under 55 additional titles. Comet C/2003 A2 (Gleason) set a new record for perihelion distance by a known comet, with q = 11.4 AU. SOHO near-sun discoveries appeared under eleven separate titles during the year (due to personnel changes in SOHO staff, there was a significant lull in reporting of such finds in the latter part of 2003). Three long-lost comets were rediscovered and numbered during the year (comets 156P/Russell-LINEAR, 157P/Tritton, and 158P/Kowal-LINEAR, on IAUCs 8118, 8128, 8215, and 8247); further, a link of comet 104P/Kowal was made with a previously unconfirmed comet reported by amateur Leo Boethin to the CBAT in early 1973 (IAUC 8255). The Lincoln Near-Earth Asteroid Research (LINEAR) CCD-search project again netted by far the most ground-based comet discoveries in 2003, with thirty credited finds on Circulars published during the year. The Jet Propulsion Laboratory's Near-Earth-Asteroid Tracking (NEAT) program was second with ten. The annual Edgar Wilson Award for comet discovery by amateurs was also announced by the Central Bureau, with five recipients in 2003.

Comet P/2003 A1 has not yet been named, because it may not be possible to determine whether or not it is identical with comet D/1783 W1 (Pigott) until it is recovered after aphelion (orbital period 7.1 years). The CBAT Director worked with the IAU Committee on Small Bodies Nomenclature during the previous IAU triennium to produce an extensive set of comet-naming guidelines that was adopted in 2003, covering the many complications that have arisen in the last two triennia due to the rise of the CCD surveys and web-based posting of data. The Director also provided the chairman's report in Sydney for the subcommittee on comet magnitudes, and there Commission 20 approved his recommendations to introduce a new scheme in this current triennium to: (a) add codes for aperture sizes and bandpasses (replacing the old 'total' and 'nuclear' magnitudes), and (b) use default exponent values of n = 3 for the heliocentric term in the standard power-law equation for ephemerides of newly discovered comets having intermediate or long orbital periods (and to state clearly the magnitude parameters used in ephemerides).

Numerous IAUCs during 2003 covered the discoveries of numerous satellites of both major and minor planets, plus some purported binary nature reports of other minor planets. Twenty-one new satellites of Jupiter, one of Saturn, five of Neptune, and three of Uranus were announced during the year (along with a rediscovery of a lost Uranian satellite first discovered in 1986 and some small objects near Jupiter V found in Galileo spacecraft data). Also, new names of satellites approved at the IAU General Assembly were announced in August on IAUC 8177.

The CBAT has a notable presence on the World Wide Web, with its Circulars posted freely for some years now after a short delay (now several weeks) following publication, which paying subscribers demand. A useful 'Headlines' webpage ( lists standard objects for which the CBAT is charged with the announcement and assignment of designations (comets, satellites, novae, supernovae). Much of the CBAT website is interlinked with the MPC website.

The number of paid subscribers to the printed edition of the IAU Circulars continued to fall, from 216 at the end of 2001, and 193 at the end of 2002, to 179 at the end of 2003. In addition, there were 37 free (complimentary or exchange) subscriptions to the printed IAUCs at the end of 2003. The printed IAUCs go to 62 addresses within North America and 117 outside of North America. The number of subscribers to the Computer Service (shared by the CBAT with the MPC) remained very stable, at around 470, as did that to Extended Computer Service, at around 70. Line charges for non-amateur contributions published on the IAUCs that do not pertain to discoveries and confirmations of comets, novae, supernovae, and satellites have been important to the funding of the Central Bureau for several decades, and will continue to be important.

As noted in the report of the Commission 6 meeting in Sydney (IAU Transactions), Minor Planet Center (MPC) Associate Director G. V. Williams, who has continued to serve as CBAT webmaster (and has been responsible for the Web CS dissemination of the IAUCs), was appointed as Assistant Director of the CBAT. As in recent years, most of the Circulars in 2002 were prepared by the undersigned, with very helpful editorial backup by Director Emeritus B. G. Marsden (who prepared the occasional Circular during the year and helped to proofread and critique most of the rest prior to issuance). New MPC staff member Kyle Smalley helped monitor CBAT activity occassionally in the Director's absence from Massachusetts. 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 2003 (causing, unfortunately, quite a number of contributions to be rejected), contining the long practice of the IAUCs being a refereed publication. 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

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