HIPark – a parked Parkes survey Goals: ultra sensitive to low column densities How sensitive ? …...
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HIPark – a parked Parkes survey Goals: ultra sensitive to low column densities How sensitive ? … optically thin at the Lyman limit exercise in observational techniques … rfi, passband calibration, … good match to long maintenance periods diffuse clouds diffuse clouds in LG in LG & Milky Way & Milky Way halo halo
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Transcript of HIPark – a parked Parkes survey Goals: ultra sensitive to low column densities How sensitive ? …...
HIPark – a parked Parkes survey
Goals: ultra sensitive to low column densities
How sensitive ?… optically thin at the Lyman limit
exercise in observational techniques … rfi, passband calibration, …
good match to long maintenance periods
diffuse clouds in diffuse clouds in LG LG
& Milky Way halo& Milky Way halo
HI Park proposers…
• Briggs• Barnes• de Blok• Freeman
• Gibson• Korbalski• Reynolds• Staveley-Smith• Zwaan
HI Park progress ?
Pilot sessions: June 2001, Dec 01/Jan 02
RIGHT NOW !!!
• maintenance period to overhaul Alt-drive• using 16 MHz filters 3380 km/s @ v= 3km/s res
QuasarAbsorption lines
Lyman forest
DLA
Metal lines
Wavelength (Angstroms)
QuasarAbsorption lines
Lyman forest
DLA
Metal lines
LL
QuasarAbsorption lines
thoroughly developed statistics !!! for metal lines…
CIVMgII/ Lyman limit(CII, FeII, SiII, …)
Relative interception cross sections …
Z=3Ly break galaxy
DLADLA
12 14 18 20 22
HI Column density distribution function Petijean etal 1993
Log f(NHI)
-10
-15
-20
Log NHI
Number of interceptions in range: N to N+dN
f(N) dN /unit Z
NHI = NH (nHI / nH)
Ionization fraction ~10-3 ?
Lyforest
IGM DLACIV
LL > 1
This Week at Parkes
Sensitivity:
to achieve 6 < 3 x 1017 cm-2
need ~ 6 hours of integration per beam
Drift scan: 15’ beam transits in ~ 1 minute
~360 transits
Barnes et al
Multibeam !!!
1x
4x
3x
Feed orientation for drift scans
Path of Survey Strip:
GalacticCoords
Limits ontiny massesin Sculptor…
3x104 dMpc2
solar masses
Dcloud >1 kpc at 250 kpc
… to fill beam
MagellanicStream
(Putman et al)
Sculptor
(Putman et al)
Path of Survey Strip:
GalacticCoords
Right Ascension
Velo
city
0
-500
2800One Day – One Beam
RA
Velo
city
-500
0
1100 km/s
Galactic Plane crossing: L ~ 250o
RA
Velo
city
-500
0
1100
RA
Velo
city
-500
0
1100
RA
Velo
city
-500
0
1100
RA
Velo
city
-500
0
1100Sun up !
Tobs(f) = [g1(f)Tantenna(f) + Trec(f) ] g2(f)
Receiver(Preamps etc)
Spectrometer(Filters etc)
Tantenna(f)
Treceiver(f)
(dominant noise)
Tobs(f)
Tant(f) = [Tobs(f)/ g2(f) - Trec(f) ]/ g1(f)
g1 (f)
g2(f)g3
SunGALACTIC PLANE, g4
Ground g5
TIME (steps)
Pilot run June 01: total power versus time
Note erratic tot-pwr in Rx-5
passband calibrated continuum subtracted
Dynamic Spectra: one receiver
Frequency Frequency
(64 MHz bandwidth)Time (vertical)
1x
4x
3x
Pilot Dec01/Jan02
8 MHz Bandwidth
DEEPCentaurusSurvey
(Disney et al)
