Warm, Dense Gas Near the Massive Protostar AFGL 2136 IRS 1 as Revealed by Absorption from the ν 1, ν 2, and ν 3 Bands of Water Nick Indriolo 1, David Neufeld 1, Andreas Seifahrt 2, & Matt Richter 3 1 – Johns Hopkins University 2 – University of Chicago 3 – University of California, Davis TI04

AFGL 2136 IRS 1 Murakawa et al A&A, 490, 673 de Wit et al A&A, 526, L5 0.5" (1000 AU) TI04

Observations CRIRES at VLT – high spectral resolution (3 km/s) – high signal-to-noise ratio (~500) Targeted v=1-0, R(0) line of HF – Indriolo et al. 2013, ApJ, 764, —2.52 μm (gaps between detectors) TI04

Observations TI04

Select Spectra TI04

35 absorption features 47 transitions probing 44 unique rotational levels FWHM=13.6±2.5 km/s v LSR =24.6±1.1 km/s

TI04 J=5 J=17

TI04 J=17 J=6

Rotation Diagram TI04

Model with Radiative Transfer TI04 N(H 2 O) = (1.02±0.02)×10 19 cm -2 n(H 2 ) > 5×10 9 cm -3 T = 506±25 K

Previous Water Observations ISO observations of ν 2 band – N(H 2 O) = 1.5×10 18 cm -2 – T = 500±200 K TI04 Boonman & van Dishoeck 2003, A&A, 403, 1003

Previous CO Observations TI04 Targeted v=1-0 bands of 12 CO and 13 CO near 4.7 μm using FTS on CFHT Also detected absorption lines from v=2-1 hot band of 12 CO Found both a warm and cold component – N( 12 CO) = (1.8±0.5)×10 19 cm -2 – n(H 2 ) > cm -3 – T = 580±60 K Mitchell et al. 1990, ApJ, 365, 554

Comparison of Results TI04 T (K) n(H 2 ) (cm -3 ) N(H 2 O) (cm -2 )OPRReference 506±25>5× × this work 500± × Boonman & van Dishoeck 2003 A&A, 403, 1003 N(CO) (cm -2 ) 580±60> ×10 19 N/A Mitchell et al ApJ, 363, 554 n > 5×10 9 cm -3 and T=500 K indicative of gas in inner envelope or disk Density can be a bit lower with radiative pumping Estimated path length of 1.3—13 AU Either way, gas is very close to protostar

Summary First study of water absorption in protostars in the NIR Results are consistent with warm, dense gas close to the central protostar Follow-up program has detected water absorption toward AFGL 4176 Important new probe of physical conditions in star-forming environments TI04

Future Work CRIRES observations of H 2 O & CO in AFGL 2136 are in queue and astrophysical lines will be more optimally shifted from atmospheric lines Proposed TEXES observations of pure rotational H 2 O transitions at μm EXES on SOFIA covers ν 2 band of H 2 O near 6 μm TI04