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| - | ====== Telecon Notes 20171011 | + | ====== Telecon Notes 20171018 |
| - | Attendance: | + | Attendance: |
| - | Notes by: Karl Young (UMN) | + | Notes by: Karl (UMN) |
| === Agenda === | === Agenda === | ||
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| Foregrounds Workshop | Foregrounds Workshop | ||
| - | The mission study is sponsoring a 3-day Foregrounds workshop in the University of California San Diego. The dates are Nov. 29 (Wednesday), | + | The mission study is sponsoring a 3-day Foregrounds workshop in the University of California San Diego. The dates are Nov. 29 (Wednesday), |
| Spectrometer and Imager | Spectrometer and Imager | ||
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| The EC has invited studies from other working groups (Fundamental Physics, Extragalactic Science, Galactic Science) to assess the science trade-offs from a mission consisting of only a 1.4 m aperture imager compared to a 0.5 m aperture imager and a spectrometer. The contributions from these WG are available from the respective coordinators and are mostly posted on the wiki page. | The EC has invited studies from other working groups (Fundamental Physics, Extragalactic Science, Galactic Science) to assess the science trade-offs from a mission consisting of only a 1.4 m aperture imager compared to a 0.5 m aperture imager and a spectrometer. The contributions from these WG are available from the respective coordinators and are mostly posted on the wiki page. | ||
| - | The EC expects a decision | + | The EC expects a decision by the end of October. You are invited to look at the available documents and provide your thoughts on this issue to any of the EC members. |
| TeamX Design and Costing | TeamX Design and Costing | ||
| - | The first detailed design and costing session will be held at JPL in mid-December. This will be an important milestone and will provide a check on our baseline designs. The design of a 1.4 m aperture imager is reasonably mature, as detailed on our wiki pages. There are however still opportunities to contribute through the weekly telecons of the imager group. | + | The first detailed design and costing session will be held at JPL in mid-December. This will be an important milestone and will provide a check on our baseline designs. The design of a 1.4 m aperture imager is reasonably mature, as detailed on our wiki pages. There are however still opportunities to contribute through the weekly telecons of the imager group. |
| Science Working Groups | Science Working Groups | ||
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| - Shaul discussed PICO and its complementarity with CMB-S4 during the August 2017 workshop at Harvard. | - Shaul discussed PICO and its complementarity with CMB-S4 during the August 2017 workshop at Harvard. | ||
| - PICO will be on display at the AAS meeting in January. There will be a 10 min talk during a 90 min special session dedicated to reviewing all 8 NASA Probe Mission Studies. | - PICO will be on display at the AAS meeting in January. There will be a 10 min talk during a 90 min special session dedicated to reviewing all 8 NASA Probe Mission Studies. | ||
| + | |||
| + | === Notes === | ||
| + | |||
| + | Decision on imager and spectrometer delayed to 2 wks from today. | ||
| + | |||
| + | periodic update comments | ||
| + | * paragraph 3 of Spectrometer and Imager: remove text in []' | ||
| + | |||
| + | Spectrometer/ | ||
| + | * Dave: Galactic trade-offs, 30K 140cm vs 4K 50cm | ||
| + | * more detail than needed here, WG document | ||
| + | * ultimate goal: resolve magnetic field from ISM to star formation scales and connect to high res telescopes, eg ALMA. | ||
| + | * Goal 1: resolve HI to HII transition in clouds (magnetic field connection between cloud and ISM) | ||
| + | * Both systems work. 4K slightly better. | ||
| + | * Goal 2: stellar cores in molecular clouds. | ||
| + | * resolution is key. resolve cores and filaments. | ||
| + | * Planck got to 5', so 3' with 50 cm is small improvement. | ||
| + | * want 0.1 pc resolved. | ||
| + | * need beams < 2 arcmin. | ||
| + | * loose all clouds for 50cm case. | ||
| + | * not frequency driven, just need resolution. | ||
| + | * BLASTPol is can do similar science. | ||
| + | * Goal #3. map mag field. | ||
| + | * again resolution limited, not sensitivity | ||
| + | * 1' --> 700 clouds. 3.4 kpc away. | ||
| + | * 3' --> 60 clouds. | ||
| + | * 4: Polarization spectrum. | ||
| + | * grain alignment and dust (John valincourt) | ||
| + | * 4K may do slightly better. | ||
| + | * 5: Mag field in other galaxies. | ||
| + | * resolution limited. need 10 beams across galaxy | ||
| + | * group excited about this, a real statiscal sample (100) at 1'. | ||
| + | * gets beyond local group if 1' | ||
| + | * 6: Diffuse ISM | ||
| + | * physics and properties of dust. Closest tie to CMB foregrounds | ||
| + | * target with lowest flux, ~10x lower than molecular cloud envelopes | ||
| + | * see turbulence power spectrum and field strength. | ||
| + | * need < 4' beams | ||
| + | * sensitivity is needed. 0.5 MJy/sr | ||
| + | * 4K sensitivity is big gain. get to 1% on 3' scales. | ||
| + | * 30K gets to ~ 7% polarized dust at 10' smoothed. | ||
| + | * assuming 2 component dust, different polarization fractions. both at 3' | ||
| + | * 30K error is 10's of %. | ||
| + | * 4K error is 1% | ||
| + | * Overall: | ||
| + | * Sensitivity limits diffuse ISM, only that. | ||
| + | * Resolution gains are molecular cloud science. | ||
| + | * Dave's overall guess: Resolution is of more interest to community. Not unanimous. | ||
| + | * Shaul: Will need to translate this to broad science case. To present to broad non-expert community. Do offline. | ||
| + | |||
| + | * Nick: Extragalactic science. | ||
| + | * Cluster cosmology (neutrino masses, w, wa): | ||
| + | * resolution of 50cm loses ~1/4 of clusters. From thermal SZ. | ||
| + | * if S4 exists, this has no real science impact. | ||
| + | * real PICO benefit is in tau measurement | ||
| + | * no S4, 15-20% hit in measurement | ||
| + | * CMB lensing S/N: | ||
| + | * PICO is good lensing experiment, comparable to S4, if 1.4m | ||
| + | * simplest assumptions: | ||
| + | * better simulations are now set up. | ||
| + | * CMB halo lensing (cluster masses). | ||
| + | * larger beam (50cm) incorporates 2-halo term, so likely even more uncertainty. | ||
| + | * y-map cleaned S/N. numbers need to be rechecked. | ||
| + | * Extragalatic point sources: largest loss at 50 cm. Still qualitative estimates. | ||
| + | * 140cm find 3000 sources where Planck found 10. | ||
| + | * 50cm, worse than Planck. | ||
| + | * Polarized point sources: can add confusion to r determination. 140cm mission informs on this. 50cm adds nothing new. | ||
| + | * Proto clusters: 140cm, image 1000's (dusty star forming galaxies). 50cm sees none. | ||
| + | * Reionization with S3 ground based. | ||
| + | * both (50 and 140 cm) give good tau, and midpoint of reionization. | ||
| + | |||
| + | * Charles: all this wants more resolutions. This is done well from ground. | ||
| + | * Nick: space gets higher frequencies. So helps dusty galaxies and CIB mitigation. | ||
| + | |||
| + | Jamie via Shaul: | ||
| + | * Charles: | ||
| + | * Jamie: -- thru Shaul -- do everything we can from space. | ||
| + | * Lloyd: Concerned that if we combine both, it is a case against Probe mission for either. | ||
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