High%20Resolution%20Observations%20in%20B1-IRS:

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High Resolution Observations in B1-IRS
ammonia , CCS and water masers
Itziar de Gregorio-Monsalvo LAEFF-INTA
(Spain)
Claire Chandler, NRAO José F. Gómez,
LAEFF-INTA Thomas B. Kuiper, JPL José M.
Torrelles, CSIC-IEEC Guillem Anglada, CSIC-IAA
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Why study molecular lines?

• Molecular lines provide information
  about T, density and kinematics.
• Quiescent medium C3H2, N2H, H13CO, DCO,
  CCS, NH3
• Shocked regions SiO, CH3OH, H2CO, HCN, CN,
  SO, SO2,H2O
• Spatial distribution of some molecules
  in star forming regions depends on
  
• - Physical
  conditions
• -
  Chemistry (time-dependent)
• They can be use as a clock to date the age
  of a dense core.
• Transparency of dust surrounding YSOs
  at centimeter wavelengths.
• Specially interesting (NH3, H2O and
  CCS)
• - NH3 (1,1) High
  density gas tracer
• - H2O
  masers High density (107-109cm-3) and warm gas
  (TK100K)
• - CCS
  Not very opaque, intense and abundant in
  protostellar cores
• Has no splitting in
  hyperfine structure

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Anticorrelation between CCS and ammonia
(Suzuki et al, 1992). Single dish
observations, starless cores.
Evolution effect CCS intense in cold and
quiescent cores Star formation
desorption of ammonia . CCS /
NH3 indicator of cloud evolution

Suzuki et al. 1992
de Gregorio-Monsalvo, 2004
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Previous studies
TMC-1
- 45m Nobeyama. - Southern part less evolved. -
IRAS object supports it.
Hirahara et al. 1992
L1521E

• CCS not depleted
• NH3 emission
• very faint.
• - Very early stage.

• - 45 m Nobeyama
• Quiescent starless core
• No outflows or submm
• emission or infalling.

Hirota et al. 2002
de Gregorio-Monsalvo, 2004
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B68

• - 70 m Goldstone
• CCS depleted on the interior
• NH3 slightly depleted too.
• More evolved stage

Lai et al. 2003
B335

• - 70m Goldstone VLA D
• Depletion at the center .
• - Contains a protostar.

Lai et al. 2003
Velusamy et al. 1995
de Gregorio-Monsalvo, 2004
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B1-IRS (IRAS 033013057)
B1 molecular cloud in Perseus (350 pc
Bachiller et al. 1990). Class 0 source
(Hurt et al. 1996). SiO emission (Yamamoto et
al. 1992) and CO (1-0) outflow (Hirano et al.
1997). Water maser emission (Furuya et al.
2001). CCS observations at 33.8 GHz with BIMA
(Lai et al. 2000).
Lai et al. 2000
Hirano et al. 1997
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VLA Observations
Goals - Study dynamics and
evolution at high resolution. - Test
CCS vs NH3 in star forming regions at high
resolution. Observations (VLA-D
configuration) - Simultaneous
observations of CCS (22.35 GHz) and H2O (22.24
GHz). - 4 IF spectral line mode.
Archive data (VLA-D configuration) -
Ammonia (23.69 GHz) from 1988.
de Gregorio-Monsalvo, 2004
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H2O masers and 2MASS image
Hirano et al, 1997

• 2MASS point source at the tip of the CO
  outflow.
• - H2O masers located at 1 in an elongated
  structure.
• - Unbound motions, probably tracing a jet
  (Torrelles et al. 1997).
• Lack of velocity gradient ( Outflow lies nearer
  the plane of the sky ? ).

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H2O masers and 2MASS image

• 2MASS point source at the tip of the CO
  outflow.
• - H2O masers located at 1 in an elongated
  structure.
• - Unbound motions, probably tracing a jet
  (Torrelles et al. 1997).
• Lack of velocity gradient ( Outflow lies nearer
  the plane of the sky ? ).

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H2O masers and 2MASS image
Multiepoch water masers
?? ()
?? ()
April 2003
October 1998
February 1999
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H2O masers and 2MASS image
Outflow configuration compatible with our
observations
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CCS resulting map

• CCS emission is clumpy.
• Redshifted clumps.
• Velocity gradient blue-shifted
  
• towards the central source
• Bound motions.
• Strong interaction between CCS
• clumps and the outflow.
• Compatible with infalling models

10000 AU at 350 pc
de Gregorio-Monsalvo, 2004
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CCS resulting map
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CCS resulting map
Plane of the sky
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Ammonia map

• - Extended emission.
• Peaks near the center of
• the source and in the S-E.
• Dynamics compatible with
• CCS velocity field.

de Gregorio-Monsalvo, 2004
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Ammonia versus CCS
Anticorrelation!!!
de Gregorio-Monsalvo, 2004
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Conclusions
CCS NH3 water maser
Dynamics, evolution stage of B1-IRS
Reflection nebula elongated in the same direction
of the outflow CO Outflow near the plane of
the sky (2MASS position). Water masers trace a
jet. CCS emission is clumpy and redshifted.
Gradient in velocity suggest a strong interaction
between the CCS and the outflow. Dynamics
compatible with infalling models. CCS / NH3
anticorrelation at small scales and in star
forming regions.
de Gregorio-Monsalvo, 2004
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Future work
Combination with single dish data to avoid the
missing short spacings in the VLA data -
CCS and NH3 maps with DSN 70 m (Madrid). NH3
VLA observation in D-configuration - More
integration time. - New receivers. H2O masers
VLA observation in A-configuration or
VLBA - Better precision in position. -
Dynamical Structure of the jet. VLA
observation in D-configuration - New regions
with CCS H2O maser emission detected
with DSN 70 m.
de Gregorio-Monsalvo, 2004