Subject: Minutes of SN Meeting At Neutrino '98 (fwd)
From: Kate Scholberg (schol@budoe.bu.edu)
Date: Wed Jul 01 1998 - 11:00:52 EDT
For those of you not present at Neutrino '98, here are Mark's minutes
of the supernova meeting.
Kate.
---------- Forwarded message ----------
Hello, All,
Here are the minutes of the international supernova network
meeting held during Neutrino '98 in Takayama, Japan.
In attendance: John Bahcall, Barry Barish, Mark Chen, Peter Doe,
Steve Elliot, Giorgio Giacomelli, Alec Habig, Jaret Heise, Guy Jonkmans,
Albrecht Karle, Art McDonald, Piero Monacelli, Hamish Robertson,
Oscar Saavedra, Kate Scholberg, Yoichiro Suzuki, Yoji Totsuka,
Mark Vagins, Chris Waltham, and Dave Wark
Art McDonald called the meeting to order at 18:40 (JST) on Friday,
June 5th. The participants (listed above) introduced themselves.
Kate Scholberg summarized the current status of the network -
MACRO has been online (feeding supernova signals to KABOOM, the current SN
network computer) since March 1998, and Super-Kamiokande has been online
since May 1998. The two experiments are therefore now running in
coincidence, though at this stage coincident SN alerts are not being
broadcast yet. This should change sometime during the summer after the
initial shakedown period is over.
A general (brief) discussion on the dynamics of neutrino
generation in supernovae ensued. Are we sure how are the pulses observed
by the current and future participating detectors going to look? Good,
theoretically-backed detector performance studies are needed using the
most up-to-date gravitational collapse models available.
John Bahcall characterized the response time of the Hubble Space
Telescope in the case of a target of opportunity -
A response in 7 days or less is almost certain, but a minimum of 2 days is
needed to slew on target. This is unfortunately too slow to catch the
earliest light which we are hoping to intercept.
However, apart from the HST, John B. assured us that Schmidt
telescopes with 6-degree-wide fields of view could be used on a much
shorter time scale to search a portion of the sky indicated by an early
alert, with the hope of pinpointing the event.
A general discussion followed on how our alert would go out to the
community. The IAU telegram and the existing Gamma-Ray Burst Network were
brought up. Most likely an early alarm issued by the supernova network
would be used to alert/target a second level search with wide-field scopes
and/or orbiting all-sky devices. This second layer (which would then
presumably be out of our hands) would issue its own refined targeting
information once the earliest light was observed, allowing narrow-field
instruments to be used productively.
This lead to talk about how to get the astronomical community on
board with us. John B. offered to use his considerable contacts towards
this end.
There was then a discussion about coordinating downtime on the
participating SN network experiments. Although minor, unscheduled
experiment drop-outs are inevitable from time to time, perhaps major
detector renovations and calibration periods could be synchronized so as
to minimize overlap with sufficient communication between experimental
groups.
Barry Barish then raised the topic of a gravity wave fast alarm
network which he is currently involved in setting up. The participating
experiments will exchange complete waveforms of their relevant signals,
and the experiments will be polled every half-hour to see who is online.
Barry proposed using this as a model of cooperation between the
experiments in the fledgling SN network, advocating that we should figure
out just what we are *technically* capable of in the absence of political
constraints and go from there.
At this point Art brought up the idea of a workshop to discuss
these and other matters at length, proposing Sudbury as a prospective
location for such a meeting.
It was accepted that such a meeting was a good idea, since we
obviously were not going to be able to address all of the important issues
during the current gathering. Kate S. and Alec Habig offered to host a
workshop at Boston, sometime in August or September (based on what the SN
folks decided via e-mail was the best time). Mark Vagins offered to play
host at Irvine for the next such meeting, which would likely be held
sometime during the coming winter months.
It was generally agreed upon that holding an international
supernova network workshop at Boston in the summer and one at Irvine in
the winter was the path to follow. Ideally each meeting would be attended
by less than thirty active participants (including theorists and
astronomers). Each experiment in the network would be represented by a
local expert who would have the responsibility of coordinating their
experiment's signal with the network.
(At this point Peter Doe volunteered and was approved as SNO's
official network representative.)
Topics suggested for the workshop(s) included SN modeling, both
theoretical and in terms of detector response; ways to get astronomers
involved; potential for increasing the power of triangulation timing by
ganging nearby detector signals together; and so on.
Mark V. then talked about his triangulation studies and computer
simulations based on the comparison of burst arrival times at different
detectors -
Using a straightforward model of neutrino arrival times and detector
responses, for a supernova 8 kpc distant, Super-K, SNO, and MACRO in
coincidence tend to define a swath in the sky. If the galactic plane is
used to constrain the allowed region of the sky then a target box
approximately 20 degrees by 10 degrees results, which is approximately
0.3% of the entire sky. Adding a fourth detector (in this case an
upgraded AMANDA) into the mix yields a point-like target box about 10
degrees by 5 degrees at 8 kpc. This is approximately 0.1% of the sky. At
4 kpc with four detectors the box shrinks to 4 degrees by 2.5 degrees.
Surely this last represents an optimistic case!
Albrecht Karle told us a little about AMANDA's status and plans
for the future. There was then some discussion as to whether we might be
able to influence the community's choice of where to build the next big
neutrino detector (we seem to have plenty of them between 36 and 47
degrees north latitude), after which it was time to adjourn the meeting.
Respectfully submitted,
-Mark Vagins
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