Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.arcetri.astro.it/~lt/projects/ovro/wams/WamsTalk.pdf Дата изменения: Tue Sep 11 16:57:10 2007 Дата индексирования: Sat Dec 22 10:04:09 2007 Кодировка: Поисковые слова: arp 220

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Interferometria Millimetrica: Applicazioni alla Formazione Stellare
Leonardo Testi -- Caltech/Arcetri


Star Formation at Owens Valley
Standard "small-scale" projects (~50% of allocated SF time) Search for massive protostars (Standard "Quick & Easy" project) Sub-mm selected intermediate mass protostars Multiple systems Outflows from low-mass protostars Envelope kinematics ...

Key "large-scale" projects (~50% of allocated SF time) Compact mm-continuum objects in dense cores (Mosaicing: wide field surveys) Chemistry in prestellar and protostellar envelopes Outflows from high-mass protostars (Mosaicing: structures > PB) Keplerian disks around pre-main sequence stars (high resolution) Chemistry in circumstellar disks

California Institute of Technology

Leonardo Testi

Osservatorio Astrofisico di Arcetri


Search for massive protostars
From protostar to UCHII From UCHII to HII Palla et al. 1991, 1993 Molinari et al. 1996, 1998ab

California Institute of Technology

Leonardo Testi

Osservatorio Astrofisico di Arcetri


Massive Class 0 Objects (protostars?)

Molinari et al. 1998
California Institute of Technology Leonardo Testi Osservatorio Astrofisico di Arcetri


3mm Survey of the Serpens Core
Plot file version 1 created 05-MAY-1998 22:15:09 V vs U for SM23 C1.DBCON.1 Source:SERPMAP Ants * -* Stokes I IF# 1 Chn# 1 60 40

(u,v) Coverage

20 Kilo Wavlngth

0

-20

-40

-60 -60 -40 -20 0 20 Kilo Wavlngth 40 60

PLot file version 1 created 05-MAY-1998 22:22:41 SERPMAP BEAM 98226.459 MHZ RAWTA.IBEAM.1

40

CS(2-1), 12m McMullin et al. 94
ARC SEC

20

0

-20

-40

1.1mm, JCMT Casali et al. 93
California Institute of Technology Leonardo Testi

Dirty Beam
40 20 0 ARC SEC Center at RA 18 27 21.998 DEC 01 12 30.00 Peak flux = 1.0000E+00 JY/BEAM Levs = 1.0000E-02 * ( -10.0, 10.00, 25.00, 50.00, 75.00, 90.00) -20 -40

Osservatorio Astrofisico di Arcetri


3mm Survey of the Serpens Core
- Hybrid Mosaic (MEM+CLEAN) - Beam 5.7"x4.3" - rms 0.9 mJy/beam - 32 discrete sources >4.5; 26 without NIR/MIR counterpart - The mass spectrum consistent with IMF

Testi & Sargent 1998
California Institute of Technology Leonardo Testi Osservatorio Astrofisico di Arcetri


3mm Survey of the Serpens Core
CS(2-1) - C34S(2-1); CH3OH(2-1) N2H+(1-0) - CS(5-4); CH3OH(5-4)

Testi & Sargent
California Institute of Technology Leonardo Testi Osservatorio Astrofisico di Arcetri


The G192 Massive Outflow

Shepherd et al. 1998; Shepherd & Kurtz 1998
California Institute of Technology Leonardo Testi Osservatorio Astrofisico di Arcetri


Circumstellar disks around TTauri stars
Spatially and kinematically resolved gaseous disks around young low mass pre main sequence (TTauri) stars

Koerner & Sargent

California Institute of Technology

Leonardo Testi

Osservatorio Astrofisico di Arcetri


Millimeter Wave Interferometry
Interferometers act as spatial filters: * Each pair of antennas samples a spatial frequency corresponding to the baseline vector as seen from the source 1111111111111 0000000000000 1111111111111 0000000000000 * Minimum Baseline sets largest structure 1111111111111 0000000000000 1111111111111 0000000000000 1111111111111 0000000000000 1111111111111 0000000000000 * Maximum Baseline sets resolution 1111111111111 0000000000000 1111111111111 0000000000000
Path (nominal) Difference

At mm atmospheric water vapour causes absorption and delay degrading the ``seeing''
Optical

1111111111111 0000000000000 1111111111111 0000000000000 1111111111111 0000000000000Water 1111111111111 0000000000000 1111111111111 0000000000000 1111111111111 0000000000000Cloud 1111111111111 0000000000000 1111111111111 0000000000000

(Absorption and Delay)

1 0 11 00 1 0

111111 000000 111111 000000 111111 000000 111111 000000 111111 000000 111111 000000 111111 000000 111111 000000 111111 000000

Delay
California Institute of Technology Leonardo Testi

1 0 11 00 1 0

Baseline

111111 000000 111111 000000 111111 000000 111111 000000 111111 000000 111111 000000 111111 000000 111111 000000 111111 000000

Correlator
Osservatorio Astrofisico di Arcetri


Atmospheric fluctuations and ``seeing''
The atmospheric phase rms is measured at Owens Valley on a 100m baseline at 11GHz Phase correction should be applied on timescales as short as 10s The Water Line Monitor is used to track and correct the ``fast'' atmospheric variations Standard QSOs observations are used to calibrate the ``slow'' variations (atm+inst)

Lay 1997
California Institute of Technology Leonardo Testi Osservatorio Astrofisico di Arcetri


The Water Line Monitor System

Woody, Carpenter & Marvel
California Institute of Technology Leonardo Testi Osservatorio Astrofisico di Arcetri