Unofficial notes from special session on "Transients" at AAS meeting in San Diego, June 7, 1998 Introduction: Akerlof - there are many small telescopes, <= 1m in size, robotic some look for GRBs but get LOTS of other data, too - other, traditional small telescopes getting shut down astronomers moving to big, 8m­class telescopes - are there interesting problems which may be addressed with small telescopes? Yes! + gamma-ray bursts (GRBs) + active galactic nuclei (AGN) + supernovae + variable stars + comets and asteroids - who might be interested in working together? 1. groups with existing robotic telescopes: need manpower for analysis of their data 2. groups seeking to build their own robotic telescopes: need information on what to do, not to do 3. individuals or groups seeking data on specific objects 4. amateurs and students seeking up-to-date images of the sky - what could the community do? A. expand role of Gamma-ray burst Coordinates Network (GCN) B. hold special workshops to discuss science with tiny scopes C. informal collaborations to share data D. build additional instruments to expand coverage, frequency range, depth Barthelmy: GCN -> Transient Astronomy Network (TAN) http://lheawww.gsfc.nasa.gov/docs/gamcosray/legr/bacodine/gcn_main.html - there are lots of robotic telescopes - some need extra targets for "idle" time - GCN is well established users send requests to GCN GCN distributes them to client instruments many robotic telescopes already signed up can do sophisticated filtering to ignore some requests, pay attention to others - idea is to extend GCN to go beyond gamma-ray bursts but where real-time or near-real-time followup is critical - existing member instruments: ROTSE LOTIS APT etc. about 10 total - transient sources besides GRBs hard X-ray transients (RXTE, BeppoSAX satellites) extreme UV (Alexis) variable stars -- cataclysmic variables, novae, supernovae AGN flares gravitational lens events (MACHO, OGLE, EROS collaborations) - other organizations which could help in the effort to observe transient sources -- already have communication in place + AAVSO + CBAT + ITW + VSNet + ISN + DSN + BASVVS + plus some individuals - GCN methods Internet socket, or via E-mail is possible very flexible filtering can act on type of source, brightness, position, etc. could add ability to act on error box size, etc. - GCN is open to suggestions looking for new sources of transient events looking for client instruments Rutledge: The Astronomer's Telegram: http://fire.berkeley.edu:8080/ - how to get information promptly to observers? - set up a WWW site to deal with distribution and notification - no human intervention, automatically and immediately forwards notices to interested parties - also saves notices in archive for future reference - has filters to allow users to select bits of information - has several authentication mechanisms - OGLE group is using Astronomer's Telegram to announce microlensing events - can include URLs and cross references - users can choose to receive, on any topic(s) of their choice, A. immediate E-mail B. daily digest C. nothing - see recent PASP article for more details Kippen: BATSE Rapid Burst Response (RBR) - idea is to derive a precise location for GRBs observed by BATSE, at the cost of a longer delay in notification - groups can choose GCN or RBR or both - RBR has humans in the loop, so slower also uses more data then GCN algorithm - yields position within 15-30 minutes of burst - error box is about 3 degrees in size considerably smaller than GCN error box - hope that new optical telescopes with approx 1-degree field of view will use RBR system in the near future - not many people appear to be using RBR right now McCullough: example of by-product of large optical surveys - using small telescopes in optical to look for low surface brightness objects - shows picture of optical R-band image with IRAS overlay the two show many matching features - "everywhere over the sky, we see IRAS emission in the optical" Vanderspek: HETE II - a followup to the doomed HETE mission - will be launched in Oct 1999 - will have 3 instruments on board 1 GRB detector, 2 X-ray cameras - always looks in anti-solar position - has dedicated ground stations all over the world, so that any transient detection can be sent to MIT and then out over GCN within seconds of event - all bursts will be within 40 degrees of the antisolar point - all bursts will therefore be at night - all bursts will be within 40 degrees of the ecliptic - easy to predict where HETE is pointing at any time - each event will be analyzed 3 times 2-sec, 20-sec, 200-sec timescales if position improves, can send out new notice each time - HETE II can provide arc-min sized error box within seconds can finally learn about EARLY optical evolution of GRBs Open discussion: - Richmond warns that one must consider carefully the consequences of opening one's telescope to requests from outside users - need careful screening process for potential users - many existing instruments produce huge amounts of data could simply go back later to look for events, if information is kept available - McCullough: just use a cheap, big, disk compress data, accept lossy compression if necessary calculates that the entire sky can be monitored freqently and kept on-line for about $1,000 per year of disk space - Henden: how to organize the transfer of data? - why should GCN "take over" astronomical communities outside the GRB community? answer: "one feed, one format" -- GCN makes life easy for robotic instruments, because it has a single format for all events - what _are_ the working optical robotic telescopes? ROTSE: working, but data not available to the world (yet) Stardial: working, data available to all UT SN Search: working, data not available to all TASS: working, data available to all, not friendly interface (other systems exist, this is not exhaustive) - how often will HETE produce alerts? 20-66 times per year - Howell: often, people have small amounts of data on interesting object -- not enough to justify publication would be nice to organize "data swap meets" - McCullough: would be nice to have a mechanism which stores the date and time and position of all observations made by all robotic telescopes could ask "was anyone looking in this direction at this time?" - McKay: we need to discuss database solutions for large surveys - Akerlof: remember, software always costs more than hardware - Marc: robotic telescopes will image new objects each night -- how to recognize the new objects promptly? how to distribute information quickly? Akerlof: microlensing projects prove the job can be done