相关论文: Diagnosing shock temperature with NH$_3$ and H$_2$…
We investigate the origin and nature of the profiles of water and ammonia observ ed toward the L1157-B1 clump as part of the HIFI CHESS survey (Ceccarelli et al. 2010) using a new code coupling a gas-grain chemical model with a parametric…
In the framework of the Herschel-WISH key program, several ortho-H2O and para-H2O emission lines, in the frequency range from 500 to 1700 GHz, were observed with the HIFI instrument in two bow-shock regions (B2 and R) of the L1157 cloud.…
L1157, a molecular dark cloud with an embedded Class 0 protostar possessing a bipolar outflow, is an excellent source for studying shock chemistry, including grain-surface chemistry prior to shocks, and post-shock, gas-phase processing. The…
Apart from being an important coolant, H2O is known to be a tracer of high-velocity molecular gas. Recent models predict relatively high abundances behind interstellar shockwaves. The dynamical and physical conditions of the H2O emitting…
We have measured the ortho-to-para ratio of ammonia in the blueshifted gas of the L1157 outflow by observing the six metastable inversion lines from (J, K) = (1, 1) to (6, 6). The highly excited (5, 5) and (6, 6) lines were first detected…
Molecular outflows powered by young protostars strongly affect the kinematics and chemistry of the natal molecular cloud through strong shocks resulting in substantial modifications of the abundance of several species. As part of the…
In the framework of the Water in Star-forming regions with Herschel (WISH) key program, maps in water lines of several outflows from young stars are being obtained, to study the water production in shocks and its role in the outflow…
(Abridged) We present a survey of the water emission in a sample of more than 20 outflows from low mass young stellar objects with the goal of characterizing the physical and chemical conditions of the emitting gas. We have used the HIFI…
We investigate on the spatial and velocity distribution of H2O along the L1448 outflow, its relationship with other tracers, and its abundance variations, using maps of the o-H2O 1_{10}-1_{01} and 2_{12}-1_{01} transitions taken with the…
We present SWAS detections of the ground-state 1(10)-1(01) transition of o-H2O at 557 GHz in 18 molecular outflows. These results are combined with ground-based observations of the J=1-0 transitions of 12CO and 13CO obtained at the FCRAO…
We present the first results of the unbiased survey of the L1157-B1 bow shock, obtained with HIFI in the framework of the key program Chemical Herschel surveys of star forming regions (CHESS). The L1157 outflow is driven by a low-mass Class…
During the formation of a star, material is ejected along powerful jets that impact the ambient material. This outflow phenomenon plays an important role in the regulation of star formation. Understanding the associated shocks and their…
As part of the WISH (Water In Star-forming regions with Herschel) key project, we report on the observations of several ortho- and para-H2O lines performed with the HIFI instrument towards two bright shock spots (R4 and B2) along the…
We present a multiline CS survey towards the brightest bow-shock B1 in the prototypical chemically active protostellar outflow L1157. We made use of (sub-)mm data obtained in the framework of the Chemical HErschel Surveys of Star forming…
We have investigated the water abundance in shock-heated molecular gas, making use of $Herschel$ measurements of far-infrared CO and H$_2$O line emissions in combination with $Spitzer$ measurements of mid-IR H$_2$ rotational emissions. We…
We present high angular resolution observations of the NH$_3$(1,1), (2,2) and (3,3) inversion transitions from the Egg Nebula, the archetypical proto-planetary nebula. The spatial distribution and kinematics of the emission in all three…
Our present understanding of high-mass star formation still remains very schematic. In particular, it is not yet clear how much of the difference between low-mass and high-mass star formation occurs during the earliest star formation…
The outflow driven by the low-mass class 0 protostar L1157 is the prototype of the so-called chemically active outflows. The bright bowshock B1 in the southern outflow lobe is a privileged testbed of magneto-hydrodynamical (MHD) shock…
In the BHR71 region, two low-mass protostars drive two distinguishable outflows. They constitute an ideal laboratory to investigate the effects of shock chemistry and the mechanisms that led to their formation. We aim to define the…
Outflows generated by protostars heavily affect the kinematics and chemistry of the hosting molecular cloud through strong shocks that enhance the abundance of some molecules. L1157 is the prototype of chemically active outflows, and a…