The B1 shock in the L1157 outflow as seen at high spatial

resolutionM. Benedettini, S. Viti, C. Codella, F. Gueth, A. Gomez-Ruiz, R. Bachiller, M. Beltran, G. Busquet, C. Ceccarelli, B. Lefloch

Accepted by MNRAS

Herscehl, CHESS meeting Roma, 11-13 September 2013

Benedettini et al. 2006

3 mm data

Plateau de Bure 2 mm data

Codella et al. 2009

Multi-velocity components along some clumps

Compact (3”-6”) high velocity clumps

B0e-HV2 v= -16 km/s

B1a-HVv= -12 km/s B1b-HV

v= -4 km/s

B0e-HV1 v= -6 km/s

Comparison between PdB spectrum (blue) and IRAM-30m spectrum (black)

CS (2-1) CS (3-2)

Flux filtering at all velocity No filtering for v<6 km/s

Largest sensible structure 14 ” HV clumps do not suffer flux filtering

LVG modeling of CS (2-1) and (3-2) of HV clumps

Constraint of the gas density!

5x103 ≤n(H2)≤ 5x105 cm3

T= 55 -132 K from Codella et al. 2009

Chemical modelChemical code (UCL_CHEM, Viti et al. 2004)

+

parametric C-type shock (Jimenez-Serra 2008)

Pre-shock density >104 cm3

30 % of CO depleted in grain during the core formation

Maximum shock temperature ~ 4000 K that implies shock velocity 40 km/s

Used by Viti et al 2011 for modelling H2O and NH3

5”

Possible direction of the jetB0e-

HV2B0e-HV2

B0e-HV1

B0e-HV1

CS (3-2) first moment

Outflow cavity

Outflow cavity

On the origin of the HV clumps

• external clumps pushed by the expanding outflow cavity?

• clumps produced by the shock?

• the jet? VLA proposal to detect the radio jet (Busquet et al)