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E-ALFA Meeting Summary
15-17 March, 2003

Karen O'Neil TOC chair


Participants
·30/63 registered consortium members present ·22 Institutions represented ·9 Countries represented


Proposed Surveys
1. All Sky Survey 2. Galaxy Environment Survey 3. ZOA Survey 4. Deep Strip Survey 5. Very Deep Survey


Proposed Surveys
1. All Sky Survey 2. Galaxy Environment Survey 3. ZOA Survey 4. Deep Strip Survey 5. Very Deep Survey


All (Arecibo) Sky Survey
·Examine HIMF at the 10
6-6.5

level

Rosenberg & Schneider `02

Zwaan, etal `97


All (Arecibo) Sky Survey
·Examine HIMF at the 10
6-6.5

level

Zwaan, etal '03 [HIPASS]


All (Arecibo) Sky Survey
·Reaching <=6 mJy/beam


All (Arecibo) Sky Survey
·Requires ~6-12 s/beam ·Drive at 2-3 times drift mode ·Drive in R.A., step in Dec ·Need repeated scans across each beam ·Need to further test stability for driven scans and to test for daytime observing ·Full Arecibo sky would take 1000-??? hours


Proposed Surveys
1. All Sky Survey 2. Galaxy Environment Survey 3. ZOA Survey 4. Deep Strip Survey 5. Very Deep Survey


Galaxies and Environment
·Examine the properties of galaxies w/i a variety of environments ·Includes groups, clusters, and isolated galaxies ·HIMF to <=5x106 Mo within groups ·Detect HVCs with v=25 km/s


Galaxies and Environment
Regions to be studied: ·Virgo Cluster ·Canes Venatici ·Around large, local galaxies ·Around dwarf groups


Galaxies and Environment
·Virgo Cluster ·200-300 sq. degrees ·4-5x106 Mo limit at 15Mpc ·120-150 s/beam ·Total = 300-600 hours


Galaxies and Environment
·Virgo Cluster ·Canes Venatici ·Two groups ­ 3 and 10 Mpc distance ·RA~12.5h, ~30-40o ·HI rich environment ·100 sq. degrees available ·3-5x106 Mo limit ·~300 s/beam ·Total = 200-300 hours


·Virgo Cluster ·Canes Venatici ·Large, local (<10Mpc) galaxies ·Examine outer HI edges ·Look for HVCs ·Approximately 100 candidate galaxies ·1 sq deg./galaxy, 100 sq. deg. total ·4-5x106 Mo limit (or less) ·300 s/beam ·Total = 200-30 hours

Galaxies and Environment


·Virgo Cluster ·Canes Venatici ·Large, local (<10Mpc) galaxies ·Dwarf Groups

Galaxies and Environment

·Exploration of different environments ·Approximately 100 sq. deg. total ·5x106 Mo limit ·300 s/beam ·Total = 200-300 hours


Galaxies and Environment
·Virgo Cluster ·Canes Venatici ·Large, local (<10Mpc) galaxies ·Dwarf Groups ·500 sq. degrees surveyed in all ·Approx. 1000-1500 hours ·Survey could be driven or drift


Proposed Surveys
1. All Sky Survey 2. Galaxy Environment Survey 3. ZOA Survey 4. Deep Strip Survey 5. Very Deep Survey


ZOA
·Local, large-scale structure ·Want to reach at least M* at 100 pc ·Possibly also including more distant survey ·Positional accuracy is critical ·Double drift scan with nyquist sampling ·700 hours observation for entire Milky Way !~5 mJy with 5 km/s resolution ·Must be compared with results from upcoming Parkes ZOA survey


Proposed Surveys
1. All Sky Survey 2. Galaxy Environment Survey 3. ZOA Survey 4. Deep Strip Survey 5. Very Deep Survey


Deep Strip Survey
Trace the HIMF to at least 1 magnitude less than previous surveys
(10 = 107Mo at 10Mpc)

Trace the HIMF across a variety of environments


Deep Strip Survey
·50-100 MHz (depending on RFI) ·4096-8192 channels/ 2 Polarizations ·Cross-correlation preferred but 9-level sampling is enough Total of 600-700 hours


Deep Strip Survey
·1o x 300o strip, 80s/beam ·Drift Scan mode, stepping by 1 beam to provide uniform sensitivity ·Nighttime observations may be desired ·No declination chosen yet Total of 600-700 hours


Very Deep Survey
How Does the Density of Cool Gas evolve with time?
· Models, based on multi- observations, (Madau plots etc), predict gas(1+z)3.2 at low-z (Pei & Fall 1999). · Damped Ly- absorption lines suggest dNDLA/dz = 0.05(1+z)1.1, implying NO intrinsic evolution of >2x1020 cm-2 absorbers - i.e. constant co-moving gas density (StorrieLombardi & Wolfe 2000).


Proposed Surveys
1. All Sky Survey 2. Galaxy Environment Survey 3. ZOA Survey 4. Deep Strip Survey 5. Very Deep Survey


Very Deep Survey
· To differentiate between evolving and nonevolving HI density, need to be able to discern a 50% change in density at z=0.15. · Need ~40 galaxies with M~109.5 M" for detection at 99% CL.


Very Deep Survey
Required observing parameters
· · · · · · · · 200 MHz, 2 pol, 7 beams (need high-z) Multi-bit (9-levels or more) Radar blanking, or v.fast dumping (1ms) 8192 channels (need 5 km/s resolution) Nighttime observations (willing to test days) Need calibration and beam parameters for all ZA Decl. near 17.5 deg or 19.5 deg, |b|>30 deg Could be near/within existing deep field


Very Deep Survey
· Possible survey parameters:
­ rms~0.05 mJy/beam (260x deeper than HIPASS) ­ 0.36 deg2 in 1000 hrs, or 70 hrs/beam ­ Volume = 8000 Mpc3 ­ 160 galaxies in range 109-10 M".
110' 12 '


Survey Needs


Hardware
· 50 ­ 200 MHz coverage · Minimum 9-level sampling · Fast dump preferred or radar blanking · (Notch filters) · 2 Polarizations · 25 kHz resolution at 200MHz · Good positional accuracy


Software
· Fits data cubes desired · Online data display · Mapping algorithms · Good positional accuracy


Other Needs
· Characterized beam pattern at all angles, positions for deconvolution · Need baselines stability studies (day vs. night, drive rates, etc.) · Good simulations (with beam patterns) for feasibility of projects