2007A&A...462..163N


C.D.S. - SIMBAD4 rel 1.7 - 2020.01.21CET17:55:48

2007A&A...462..163N - Astronomy and Astrophysics, volume 462, 163-172 (2007/1-4)

Warm SiO gas in molecular bullets associated with protostellar outflows.

NISINI B., CODELLA C., GIANNINI T., SANTIAGO GARCIA J., RICHER J.S., BACHILLER R. and TAFALLA M.

Abstract (from CDS):

We present the first SiO multiline analysis (from J=2-1 to J=11-10) of the molecular bullets along the outflows of the Class 0 sources L1448-mm and L1157-mm, obtained through observations with IRAM and JCMT. We investigate the physical properties of different types of bullets, in order to explore their excitation conditions and constrain their formation and evolution. We have computed the main physical parameters (nH2, Tkin, NSiO) in each bullet and compared them with other tracers of warm and dense gas and with models for the SiO excitation in shocks. The bullets close to L1448-mm, associated with high velocity gas, have higher excitation conditions (nH2∼106cm–3, T>500K) than the L1157 bullets (nH2∼1-5x105cm–3, T∼100-300K). In both the sources, there is clear evidence of the presence of velocity components having different excitation conditions, with the denser and/or warmer gas associated with the gas at the higher speed. In L1448 the bulk of the emission is due to the high-excitation and high velocity gas, while in L1157 most of the emission comes from the low excitation gas at ambient velocity. The observed velocity-averaged line ratios are well reproduced by shocks with speeds vs larger than ∼30km/s and densities ∼105-106cm–3. Plane-parallel shock models, however, fail to predict all the observed line profiles and in particular the very similar profiles shown by both low and high excitation lines. The observations support the idea that the L1157 clumps are shock interaction events older than the L1448 bullets close to the driving source. In the latter objects, the velocity structure and the variations of physical parameters with the velocity very closely resemble those found in optical/IR jets near the protostar, suggesting that similar launching and excitation mechanisms are also at the origin of collimated jets seen at millimetre wavelengths.

Abstract Copyright:

Journal keyword(s): ISM: jets and outflows - ISM: molecules - shock waves - submillimeter - ISM: individual objects: L1448-L1157 - line: formation

Simbad objects: 21

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Number of rows : 21

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NAME W 3 OH HII 02 27 04.1 +61 52 22           ~ 933 2
2 LDN 1448 DNe 03 22.5 +30 35           ~ 462 0
3 [BCM90] B2 ? 03 25 36 +30 44.5           ~ 8 0
4 [BCM90] B1 ? 03 25 37 +30 45.5           ~ 8 0
5 [SDA2014] West4 Y*O 03 25 38.83 +30 44 06.2           ~ 241 1
6 NAME LDN 1448-mm Y*O 03 25 38.83 +30 44 06.2           ~ 295 0
7 [BCM90] R2 ? 03 25 40 +30 43.5           ~ 8 0
8 [BCM90] R4 ? 03 25 42 +30 41.9           ~ 12 0
9 IRAS 03407+3152 cor 03 43 56.52 +32 00 52.8           ~ 290 0
10 IRAS 04166+2706 Y*O 04 19 42.627 +27 13 38.43           M 108 1
11 NAME Mon OB1 G PoC 06 41 12 +09 55.6           ~ 107 0
12 BHR 71 MoC 12 01 36.810 -65 08 49.22           ~ 114 0
13 [TB95] R0 red 20 39 00 +68 03.3           ~ 13 0
14 [TB95] R1 red 20 39 00 +68 04.5           ~ 12 0
15 NAME LDN 1157-mm Y*O 20 39 06.2 +68 02 15           ~ 155 0
16 LDN 1157 DNe 20 39 06.4 +68 02 13           ~ 467 0
17 [DE95] LDN 1157 B2 out 20 39 09.3 +68 00 44           ~ 56 0
18 [DE95] LDN 1157 B1 out 20 39 11 +68 01.3           ~ 170 0
19 [TB95] B0 blu 20 39 11 +68 01.7           ~ 17 0
20 [WBN74] NGC 7538 IRS 1 Y*O 23 13 45.318 +61 28 11.69           ~ 361 3
21 [BCM90] R1 ? ~ ~           ~ 8 0

    Equat.    Gal    SGal    Ecl

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