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JWST NIRCam GTO meeting 8-10 June 2014, Zurich NIRISS GTO Planemos in star-forming regions David Lafrenière and the NIRISS team October 20, 2015
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NIRISS team meeting 20-21October 2015, Montreal Substellar IMF in SFRs Shape of IMF at lowest masses can inform BD/planet formation Turbulent fragmentation, dynamical ejection from multiple systems, disk fragmentation and ejection, all of the above IMF well characterised down to ~10 Jupiter masses in several regions dN/dM ~consistent with a single power law from 0.5 Msun to ~12-15 Mjup Possible turnover below this mass regime Star-to-BD ratio is typically in the range 2-5 2 Scholz et al. 2012a,b
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NIRISS team meeting 20-21October 2015, Montreal Going below ~5-10 Mjup In the field, microlensing surveys indicate there could be ~2 PMOs per star (Sumi et al. 2011), but result is highly debated Stark contrast to scarcity seen at 5-12 Mjup in SFRs If true, a large population of 1-5 Mjup PMOs must exist in SFRs ~100 such objects in each nearby SFRs Different origin than the more massive BD, formed as planets? In SFRs, little/no robust statistics <10 Mjup Need to establish firmly whether there is a turnover at ~10 Mjup Fragmentation limit, bottom of star formation Need to quantify the population of PMOs, especially <5 Mjup. Rogue planets, regime of planet formation We propose to do a survey using NIRISS WFSS to find isolated planetary mass objects (PMOs) down to 2 Mjup in nearby SFRs 3
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NIRISS team meeting 20-21October 2015, Montreal A NIRISS search for rogue planets in SFRs A survey ~75 sq. arcmin sensitive down to 2 Mjup in each of 3 nearby (relatively dispersed, low A V ) SFRs: Oph, ~1 Myr, ~140 pc Cha I, ~2 Myr, ~160 pc NGC 1333, 1-3 Myr, ~230 pc 15 fields (2.2’x2.2’) per region Using Wide-Field Slit-less Spectroscopy (WFSS) mode: Spectroscopy of every source in the 2.2’x2.2’ FOV at resolving power of ~150, in F150W and F200W Complemented by imaging in F115W (and F150W/F200W) A. Scholz, R. Jayawardhana et al. 4
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NIRISS team meeting 20-21October 2015, Montreal WFSS sensitivities, F150W 5 ~5~3~2~1.5 Corresponding Mjup at 3 Myr & 200 pc: ~1
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NIRISS team meeting 20-21October 2015, Montreal A NIRISS search for rogue planets in SFRs Goal of 2 Mjup at a minimum S/N of 10 per resolution element for all regions observed (1-3 Myr, Av<5-10) At ~150 pc, corresponds to AB mag of ~22.2 in H and K (~150 s and ~240 s per field, resp.) ~6 hr for Cha I & r Oph At ~250 pc, corresponds to AB mag of ~23.3 in H and K (~400 s and ~600 s per field, resp.) ~8 hr for NGC 1333. Including overheads, amounts to grand total of ~20 hr. We have deep ground-based imaging (H~21-22) of all regions to be targeted (from SONYC) and we can select fields to avoid avoid bright stars, high extinction regions and reflection nebulas 6
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NIRISS team meeting 20-21October 2015, Montreal A NIRISS search for rogue planets in SFRs 7 Scholz et al. 2012 The R150 H & K spectroscopy resolution is sufficient to unambiguously identify planetary mass objects and provide a first estimate of temperature and thus mass. Imaging is further useful (and low cost) to estimate luminosities, and verify extinction. Estimates of luminosity, temperature and mass can be used to check consistency of models.
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NIRISS team meeting 20-21October 2015, Montreal Outcomes Most optimistic scenario (Sumi et al. field microlensing result is true) ~2-5 detections per NIRISS field observed (0.5-1 per sq.arcmin) About 100 objects in total (of ~2-5 Mjup) Perhaps half of this is more reasonable Most pessimistic scenario (microlensing result is false) Based solely on extrapolation of known IMF: 5-6 in total for program (0.1-0.3 per field). But this is uncharted territory! Could be more? In all cases, every object found is brighter than H Vega ~21 and easily doable with high resolution spectroscopy NIRSpec R~2700 at S/N~20: 60 min at H and ~10 min at K E.g. measure C/O ratio to trace formation mechanism 8
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NIRISS team meeting 20-21October 2015, Montreal Possible follow-up/collaborations NIRSpec spectroscopy need broad spectral coverage from 1-5 um to improve Teff/mass estimates need higher resolution to constrain shape of the H-band better to see atomic features to measure abundances to test for accretion Coverage & resolution for testing atmosphere models models are not great in this Teff regime (1000-2000 K), testing models and improving fundamental parameters (and building the mass function) will go hand in hand. MIRI photometry would be interesting to test for disks 9
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NIRISS team meeting 20-21October 2015, Montreal NIRCAM PMOs in SFRs program Similar but based on a different strategy Target denser SFRs whose core is well-matched to NIRCam FOV One pointing per SFRs (in the core) & multi-color imaging: F070W, F115W, F277W, F444 W +4 intermediate band filters, F140, F182, F300, F335 ~8 hours total per field (8 filters), reach 20 Gives initial selection, about 1/3 are expected to be contaminants Follow-up of every candidate with NIRSPec R=100 spectroscopy for confirmation/characterization I don’t know how long this will take… M. Meyer et al. 10
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NIRISS team meeting 20-21October 2015, Montreal NIRCAM Outcome: ~50-100 PMOs per field, based on extrapolation of known IMF and some reasonable assumptions. Fainter objects than NIRISS >10-20 additional mag of A V vs the NIRISS program, so >2-4 mag fainter Detailed characterization at high resolution, wider spectral coverage more difficult. 11
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NIRISS team meeting 20-21October 2015, Montreal NIRISS and NIRCam programs Are the NIRISS/NIRCam programs competing? Is one better? Are they complementary? My view is that both programs are complementary and should both be done (and well coordinated) Shared by Aleks Scholz and others. NIRISS: bright objects for follow-ups, access to dispersed regions/outer parts of cluster/regions with low A V NIRCam: more but fainter objects, better for statistics, access to dense regions/core IMF measurement is difficult, going at it with multiple approaches is best. Could do one region in common with both instruments. 12
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