IAU Central Bureau for Astronomical Telegrams

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What Kinds of Discovered Objects to Report for Publication on IAUCs

The IAU Circulars (IAUCs), published by the Central Bureau for Astronomical Telegrams (CBAT), officially announce new discoveries of supernovae, novae, comets, satellites of major/minor planets, and other interesting transient astronomical objects (particularly those that are unusual, such as cataclysmic variables that have outbursts less frequently than once every year or two, or very unusual variable stars or non-stellar objects discovered at optical or non-optical wavelengths, often assessed in consultation with referees who may or may not be members of Commission 6). The IAUCs are also the official source giving new IAU designations and names of such objects as comets, supernovae, satellites of solar-system planets, and some unusual variable stars such as novae. Meteors and fireballs, which are technically part of the earth's atmosphere (and thus not astronomical), are generally not covered on IAUCs, though some of the more interesting meteor showers (or storms) are covered if public and scientific interest is high.

Novae in nearby galaxies outside the Milky Way are a particular problem, because (for example) novae in M31 are relatively common with respect to those in the Magellanic Clouds or the Milky Way, which have only a few observed novae each year. There are roughly a couple dozen novae to be discovered (brighter than about mag 20) in M31 each year [cf., e.g., Capaccioli et al. 1989, A.J. 97, 1622; Hatano et al. 1997, Ap.J. 487, L45; Aguirre 2000, Sky Tel. 99(6), 80]. Historical precedent has been therefore to publish announcements of all novae discoveries in the Milky Way and in the Magellanic Clouds on IAUCs, but not all discoveries of novae in M31. Occasionally, as space permits, the IAUCS will publish some information on newly discovered novae in M31, particularly if they include detailed information that include precise astrometry and spectroscopic data; brighter novae in M31 (i.e., those of mag 15 or brighter; cf. Sharov 1989, Sov. Astron. Lett. 15, 5) will naturally receive stronger attention. But traditionally, for many decades, M31 novae discoveries have been announced in the main astronomical literature in groups, representing novae discovered over spans of a year or often many years (e.g., Sharov and Alksnis 1997, Astronomy Letters 23, 540), and the IBVS are another proper location for publishing novae discoveries in other galaxies more promptly. There is also a new CBAT webpage for apparent M31 novae.

Faint supernovae suspects (especially those fainter than visual or red mag 19) can also be problematical. Because of the large numbers of these objects and the relatively few observers/telescopes able to observe them, discoverers of such faint objects should be sure that such objects close to galactic nuclei are in fact not parts of active galactic nuclei instead of being supernovae (this is a fairly common problem); in particular, observers of any objects fainter than mag 17 or 18 that are within a couple of magnitudes of their limiting magnitude for reference frames are encouraged to consult the catalogue by the Vérons. Foreground variable stars are also relatively commonplace objects in front of (or near) distant galaxies, and the best way to rule out such foreground variables is to provide spectroscopic confirmation or else deep images showing nothing several magnitudes fainter than the supernova suspect. Supernovae that are confirmed spectroscopically, or that satisfy the guidelines set down on IAUCs 6737 and 6739, are given permanent designations and announced on CBETs and/or IAUCs (and tabulated here at the CBAT supernova catalogue webpage). Strong candidates that generally are fainter than mag 20 and lack spectroscopic confirmation are now being provisionally designated and listed at the PSN webpage.

The IAUCs also publish scientific contributions of a follow-up nature regarding astronomical objects of a transient nature. With the exception of initial announcements and confirming astrometric and/or spectroscopic information regarding novae and supernovae, published items are subject to line charges (cf. IAUC 6529). Details on the current line charges are available.

When sending reports to the CBAT for possible publication, please try to follow the IAUC conventions regarding textual items (e.g., affiliations, units, references, defining acronymns, etc.). Specifically:
  • Remove any and all html-encoding from your e-mail, as we do not use web browsers to read e-mail; the inclusion of html encoding in your e-mail may cause messages to be delayed or even deleted by accident.
  • To avoid delays, please use IAU-approved designations (see information on IAU designations and IAU recommendations for designations; an example is SDSS designations);
  • To avoid delays, please use standard IAUC procedures for listing authors (first and middle initials, last full name; maximum of three authors, if possible*) and affiliations (providing FULL institutional names, not abbreviated names or acronyms unless defined first, with diacritical marks in TeX form; amateurs should not give their private observatory name but rather city/town and state/country).
  • *Ideally, the "author(s)" whose name(s) appear(s) at the beginning of the published item should be only the person communicating the item to the CBAT (and that is almost always only one person) and/or the person(s) who actually wrote the text to be published. Affiliations need only be given to these one (or two, or three) people, to save space. Other people who made observations, reduced data, or contributed in an important way to discussions involving the published item can be mentioned by name in the text where appropriate (without affiliations). Please note that we generally require that the person contributing the item for publication be listed either as the first name for the item or as one of the co-authors. It is not appropriate to publish an item contributed by a person whose name does not appear prominently near the beginning of the item, and the IAUC editors will add on the name of the contributor to the very beginning if deemed necessary.
  • Include references as much as possible, to explain any concept that is not obvious to general astronomy readers; reference to previous items regarding the same object on IAUCs is particularly encouraged.
  • References should be given as follows: last name of author, year of publication, journal name volume number, page number. (In the case of two authors, both last names should be given; in the case of more than two authors, give only the first author's last name, followed by et al.; example: Clinton et al. 1925, Ap.J. 252, 16.)
  • To avoid delays, please use IAU-approved units (s for seconds, optical wavelengths in nm, instrument apertures in meters, etc.);
  • Use TeX notation for exponents, subscripts, and special math characters); positions (give to proper number of digits -- R.A. usually given to one more significant digit than Decl., e.g.), and times (give to decimals of a day in Universal Time; never use MJD), etc.
  • Those reporting discoveries of new objects need to give full information regarding proper sources (atlases, catalogues, etc.) that have been checked, in order to bolster their evidence.

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