A Transient AstronomyA Transient Astronomy“Free for All” at “Free for All” at

The Astronomer’s TelegramThe Astronomer’s Telegram

Derek B. Fox, CaltechDerek B. Fox, Caltech

Robert E. Rutledge, McGillRobert E. Rutledge, McGill

VO Events MeetingVO Events Meeting

Pasadena – 13 April 2005Pasadena – 13 April 2005

A Transient Astronomy Free-A Transient Astronomy Free-for-Allfor-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 Astronomer’s TelegramThe Astronomer’s Telegramin Contextin Context

The Astronomer’s TelegramThe Astronomer’s Telegram

• Online December 17, 1997

• Founder: Bob Rutledge• Application of the Web to

transient astronomy• All Perl CGI• Daily emails + Instant

Notices

On the same day:

• GCNs #9 to #13 on GRB971214

• IAUC 6791, also on GRB971214

ATEL ApproachATEL Approach

Philosophy:

• Universal access• Vet authors on registration• Trust them thereafter . . .

(can revoke if necessary)• Complete automation• Instant distribution

– On web in seconds– Email in minutes

(instants)– A must for transient

astronomy• Free for all

Universal Access Universal Access Collaboration 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 UsageATEL Usage

In the 7 1/2 years since:

• ATEL #457 – all freely available via ADS query

• GCN 3255• IAUC 8509 (+1718) –

approx. 5000 notices• CBET 137 – New since

Jan 25, 2005• Multiple project-

specific mailing lists

ATEL UsersATEL Users

• Authors self-describe telegrams by bandpass and subject matter

• Multiple selections are allowed & encouraged

• 107 “Requests for Observations”

• 18 “Comments”

323 X-ray

162 Optical

109 Radio

103 Gamma-ray

80 Infrared

10 Far-Infrared

10 > GeV

7 Ultraviolet

7 Millimeter

6 Submillimeter

ATEL SubjectsATEL Subjects327 Transients

263 Binaries

170 Black Holes

146 Neutron Stars

104 Pulsars

33 Variables

24 SGRs

22 Supernovae*

20 GRBs

15 Stars

12 AGN

9 Novae*

6 CVs

6 SN Remnants

5 Glob’r Clusters

5 Microlensing

3 Quasars

1 Comets

1 Meteors

The Astronomer’s TelegramThe Astronomer’s Telegramin Actionin Action

ATEL LessonsATEL 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 didn’t work

• Observers encouraged to interpret results

Registration of UsersRegistration 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 Email NoticesInstant Email Notices

Exception to daily emails intended for:

• Discovery with new coordinates

• New outburst of known transient

• Typing of supernova• Request for observations

From Astronomer’s TelegramFrom Astronomer’s Telegramto Virtual Observatoryto Virtual Observatory

(Events)(Events)

Elements of VO EventsElements 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 EventsElements of VO Events

ATEL:

• Schema– Author names + affiliations– First author email address– Telegram Title (string)– Wavebands + Object types– Text description

• Distribution channels– Website, Email, RSS– Event verification by

visiting the website• Registration service

– Personal contact by Editors

The Information RegistryThe 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 EventsFrom ATEL to VO Events

VO-Events:

• XML Schema– Ongoing process

• Distribution channels– Website, Email, RSS,

SOAP– Identity verification– Content verification

• Registration service– ?

The VO Event Free-for-AllThe 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