A Transient Astronomy Free for All at The Astronomers Telegram Derek B. Fox, Caltech Robert E. Rutledge, McGill VO Events Meeting Pasadena – 13 April 2005

A Transient Astronomy Free-for-All ATEL in Context –What need does it serve? –How does it work? ATEL in Action –How has it been used? –What have we learned? From ATEL to VO Events –Minimal standards for VOE –ATEL-like components –New/Novel components

The Astronomers Telegram in Context

The Astronomers Telegram Online December 17, 1997 Founder: Bob Rutledge Application of the Web to transient astronomy All Perl CGI Daily s + Instant Notices On the same day: GCNs #9 to #13 on GRB IAUC 6791, also on GRB971214

ATEL Approach Philosophy: Universal access Vet authors on registration Trust them thereafter... (can revoke if necessary) Complete automation Instant distribution –On web in seconds – in minutes (instants) –A must for transient astronomy Free for all

Universal Access Collaboration Observers expect others to be aware of ATEL Watch ATEL for transient events Respond by initiating observations Post results to ATEL Extremely rich phenomena are intensively observed, without prior agreement, between major observers at the largest facilities

ATEL Usage In the 7 1/2 years since: ATEL #457 – all freely available via ADS query GCN 3255 IAUC 8509 (+1718) – approx notices CBET 137 – New since Jan 25, 2005 Multiple project-specific mailing lists

ATEL Users Authors self-describe telegrams by bandpass and subject matter Multiple selections are allowed & encouraged 107 Requests for Observations 18 Comments 323X-ray 162Optical 109Radio 103Gamma-ray 80Infrared 10Far-Infrared 10> GeV 7Ultraviolet 7Millimeter 6Submillimeter

ATEL Subjects 327Transients 263Binaries 170Black Holes 146Neutron Stars 104Pulsars 33Variables 24SGRs 22Supernovae* 20GRBs 15Stars 12AGN 9Novae* 6CVs 6SN Remnants 5Globr Clusters 5Microlensing 3Quasars 1Comets 1Meteors

The Astronomers Telegram in Action

ATEL Lessons Personal registration of users HTTP User + Password sufficient to verify (cookie) Cryptographic signatures still rare Content verification via the website Authors have pushed the envelope for instant notices Theory telegrams didnt work Observers encouraged to interpret results

Registration of Users Necessity of vetting users Verify identity by personal contact Professional astronomers and graduate students Considerations: Several requests per year from non-astronomers Amateur astronomers would like to post Usually users attempt to post prior to registration

Instant Notices Exception to daily s intended for: Discovery with new coordinates New outburst of known transient Typing of supernova Request for observations

From Astronomers Telegram to Virtual Observatory (Events)

Elements of VO Events XML Schema –Event Coordinates –Event Properties –Descriptive elements Distribution channels –Vetted in advance –Providing event verification –Cafeteria style selection (not all or nothing) Registration service –Identity –Qualifications

Elements of VO Events ATEL: Schema –Author names + affiliations –First author address –Telegram Title (string) –Wavebands + Object types –Text description Distribution channels –Website, , RSS –Event verification by visiting the website Registration service –Personal contact by Editors

The Information Registry VO Events may enable machine-intiated observations on subsecond timescales. To work in this fashion they must have registry metadata enabling identity and content verification If these are not included in the VO event schema then events will be distributed only between previously known & trusted sources, and the utility of a universal schema will be lost.

From ATEL to VO Events VO-Events: XML Schema –Ongoing process Distribution channels –Website, , RSS, SOAP –Identity verification –Content verification Registration service –?

The VO Event Free-for-All ATEL has been up for 7.5 years Instant access enabling progress in transient astronomy Registration of users has allowed us to trust them Increasing usage + diversity of subject matter VO Events as a free-for all: Flexibility of subscriptions Flexibility of subject matter Freedom of access Verification of author and content provided