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