Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.naic.edu/alfa/ealfa/meeting2/handouts/proposals_summary_v1.ps Дата изменения: Sat May 13 00:11:10 2006 Дата индексирования: Sun Dec 23 05:23:05 2007 Кодировка: Поисковые слова: http astrokuban.info astrokuban

E­ALFA, Day 1
Consortium Rules & Guidelines:
All contentious issues deferred until tomorrow, to give a chance to talk and think
about the issues
Steering Committee Options:
(1) Steering committee as described in document
(2) Coordinating committee made of at least of the PI of each survey. Their
mandate is (1) to organize e­alfa surveys with all other consortia, and (b)
to provide strong leadership for the E­alfa consortium
Consortium Rules Options:
(1) E­ALFA adopts rules for itself and all subcommittees
(2) E­ALFA recommends rules to individual subcommittees
(3) E­ALFA adopts rules, but only recommends them to subcommittees -- the
result is the consortium is open to all, but subcommittees can have their
own rules
(4) Martha & Ricardo will write a version to give to me by ?lunch?

E­ALFA, Day 1
ALFA Overview
. T rcvr = 6­8K, from 1.25 -- 1.55 MHz
. Backends:
o WAPP only right now
o Extragal backend delivery by Jan 2006
f Direct FFT from xilinx cards
f At least 25 kHz resolution
o Pulsar backend by Jan 2005 (although date has slipped)
f Direct FFT from xilinx cards
o G­ALFA delivery by Jan 2005
. Comissioning Plans:
o See GANT chart
. Comissioning Results:
o Efficiency ~ 0.8 for all receivers
o Dynamic range of 28 dB
o Gain of central pixel: from 10.5 at zenith through around 10
from za=5­15, then falls to 9 by ZA=19
o Tys at zenith of 30, goes to 36 at ZA=19
o SEFD of 2.9 -- 3.2 for za up to 15, then rises to 4.1
o HPBW = 3.3' in azimuith, and 3.8 in zenith
o Outer Beams:
f Gain~8,8.5,8.5,11,9,8.5,8.5
Sensitivity vs L­wide:
o Central pixel is ~slightly less than L­wide, outer pixels 10­20%
down from that
o Rough average sensitivity, then is ~85­88% of the current L­wide
o Pointing and sidelobes of central beam look much better than
Lwide


E­ALFA, Day 1


Proposals:
ALFALFA, Discussion:
. Above numbers are only for brightest galaxy catalog. True numbers for
HIPASS is going to be less than 10 mJy.
. Argument was made that while large area will more low mass galaxies,
you have a problem with peculiar velocities. Instead, you are better off
having a deeper survey where pec. velocities don't matter as much.
. Argument made that a single pass survey will suffer severely from
following up too much RFI. Counter argument made that by moving the
telescope quickly this will be alleviated.
. Concerns/Questions:
o Better than HIPASS?
o Area vs. Depth?
o Scans ­ how many
o RFI Rejection
o What early science will be achieved with this survey?

ULTRADEEP Survey, Discussion:

. Concerns/Questions:
o Interference
o Does rms go down as sqrt(t)?
o Baseline issues
o Efficiency
. Question was raised as to how many galaxies are expected to be detected
that aren't seen optically. This is being raised in context of where the best
area to search. Response is that currently the plan is to have an HI mass
selected sky region.
. Its pointed out that there are clean bands below 1225 MHz that are clean
which may want to be exploited. In this case, we may want a wider
bandpass.


MEDIUM DEEP Survey, Discussion:
. Concerns/Questions
o What can we do in a given time?
o What regions should be studied?
o What area should be covered for a given region?
o Explain the table -- there are apparently some errors


ZOA Survey, Discussion:
. Concerns/Questions:
o Commensual Observing or survey?
o Better than HIPASS? (Yup -- different part of sky, better spatial
and velocity resolution, higher sensitivity)


High |b| Drift Survey:
. What will the survey do/not do?
. Young people involved
. Coordinate with other surveys
. What can we learn from this?





To be continued after lunch.....