Notes from Telecon 2

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Key Project Proposal Telecon 2, November 30th


Contents

1. Science Aims

-What theories to do we hope to test with HCN, HCO+, N2H+ at 0.15 km/s spectral resolution, 5 arcsec angular resolution/1200 AU spatial resolution, over a parsec size field?
-What will sound good in a proposal?
A. Kinematics
  • Trace kinematics from pc to 1000 AU scales
  • Compare with stellar content
B. Testing Global Models of Star Formation
  • Turbulence
    • Compare observed large scale density structure to simulations of converging sonic/supersonic turbulent flows
  • Magnetic Fields
    • We won't be able to say anything directly about the magnetic fields, but we can observe the kinematic structure and determine whether it is a better match to star formation models with or without magnetic fields and turbulence.
    • Collaborate with a project that is doing polarization measurements of individual cores in Perseus and Serpens? Dick is doing something with this.
C. Core Formation and Identification
  • Compare cores to broader scale continuum emission to understand how the cores form from the larger cloud environment.
  • Compare core locations to the large scale and local velocity structure of the cloud.
  • Do we have the velocity resolution to look for subsonic/supersonic boundaries near cores throughout the field?
  • High resolution, wide-field mapping in continuum and multiple tracers good way to test new core clumping algorithms.
D. ALMA Connection
  • What is it? Will be subtle part of proposal.


Major themes discussed during telecon:
1. How kinematics change in different regions of star formation
2. Look for pieces of clouds that show different levels of evolution
3. Test current theories that the size of stars are set by how much material is in a turbulent cell
4. Woojin mentions looking for changes in density distributions across the cores.
5. Magnetic fields:
  • Dick Plambeck happy to include our cores in his survey area
  • (Crutcher) Comparison of line widths of neutral and ionized species; differences in line widths tell you about the magnetic fields; 0.15 km/s should be good enough to resolve line to get good widths; another reason for using 8 MHz bands; if see expect similar distributions of ion and neutral from astrochemistry, then difference may be due to magnetic effects; we can at least test this assumption with high resolution mapping and say something about different species not being co-located
Follow-up Science discussed:
1. Targeted higher resolution observations of 1333 cores with CARMA. Something going in this deadline. Who is interested?
2. EVLA proposals to get complementary ammonia data for temperatures and another neutral tracer.
ARO discussion:
1. Apply in January for 12-m to:
A. Test if we will actually detect HCN, HCO+, N2H+ in the fainter regions
B. Map 3x larger area to understand larger context of star formation around CARMA higher resolution area
C. Map with more molecules? isotopes?


2. Cloud Selection

  • Expect sensitivity to be ~0.2 K in 5 arcsec beam at 0.15 km/s
  • In NGC 1333, We are detecting N2H+ at 8 K in strongest regions, and HCN/HCO+ up to 10-12 K
  • For now, expect to do 1 sq arcmin in 1 hour
  • Expect 300 hours for Perseus, and 300 for Serpens
  • Goal to capture how cores are forming, so no targeted mosiacs --- stick with rectagles
  • Cover range of star formation activity
  • Perseus (Andrea, Jens, John, Shaye)
1. B1s: We think that the southern part of B1 (indicated with the red and yellow rectangles) might be an interesting target. The goal would be to study the properties of the gas and dust along this "filament" which contains Class I and Class 0 sources in the northern part, prestellar cores in the central part, and is made of diffused gas in the southern part. The advantage of observing this region would be that we can start with a smaller box (e.g. the red one) and, depending of the achieved sensitivity and available time, extend the observations toward south-west in the region with less active star formation. A region that might be similar to B1 is L1448.
2. Go after region with fair gathering of emission but not much else known?
  • Can observe south of L1448 (L1441??) where there are cores, but the locations between Herschel and SCUBA disagree in this less studies field
  • Will we detect anything in these regions? Jens has info from Kirk 2007 N2H+. Also might have GBT NH3 map.
  • Risk mitigated with ARO observations before CARMA -- can propose to do fainter stuff in 2nd or 3rd semester -- also have backup brighter cloud
  • Serpens (Hector, Manuel, John)
1. Serpens Main:
  • Active star formation.
  • Good comparison to 1333 activity. Do all active regions look similar?
2. Sepens South:
  • Active in Center
  • Regions with less activity on ends
  • Star formation at connection of a number of filaments
  • Compare to B1s?
3. Serpens B:
  • Not studied outside of continuum -- 19 YSO candidates in there. Not sure if any starless.
4. Filament near Serpense South?
  • Bit to east --- similar length filament and lower star formation --- considered for another proposal



3. Contributions to CARMA

  • Big part of contributions to CARMA could be the optimization of single-dish observing mode and mosaicing in general
  • Continuous integration? Flag data when >20% antennas are still slewing
  • Data products:
  • Release cloud from previous semester to website within 6 months (required to release within year)
  • Get candidate lists for followup in the next semester



4. Proposal Job Distribution

  • Lead writers (1-2 people since time is so short): Lee and :(
  • Anyone who has written material that is close to point on our science goals to use in proposal:
  • Dick will get Lee paragraph about line widths and magnetic fields
  • Cloud Subgroups for Figures and Facts:
  • Serpens: Hector and team (Manuel, John, ...)
  • Perseus: Andrea and team (Jens, John, Shaye, ...)
(subgroups need to get lead writers: images of regions, brief descriptions of regions, why they were selected, tabular form of what is known and what data is available (supporting molecular line observations, continuum, single-dish, etc.), how we are going to convince the referee that we will not just be observing large blank fields (e.g. c18o was observed with similar strength in 1333 vs. new cloud, and we saw 1333 plenty bright in n2h+ so we can expect similar results))
  • Current NGC 1333 Figures: Shaye
  • CARMA operations contributions: Marc, Peter
  • Data products and timeline: Shaye, Lee



5. Thesis work?

  • UMD: Shaye
  • Illinois: Nick Hakobian can use line widths to test magnetic field ideas
Others?



6. Expanding group?

  • 1. Leonardo Tessti: bring Herschel daa
  • 2. Konstantinos Tassi: theory



7. Proposal Completion Timeline

  • Cloud details, figures, tables to Lee and lead writers by Friday afternoon
  • First draft circulated by Saturday afternoon
  • Comments back to lead writers/figure makers by Sunday afternoon
  • Second draft sent out Sunday evening
  • Comments and improvements throughout day on Monday
  • Submit by 6 pm EST
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