[Other -- Oral ] 
 Modeling the X-ray emission from jets observed with Chandra 
Rosaria Bonito, DSFA-UNIPA-INAF-Osservatorio Astronomico di Palermo 
R. Bonito (DSFA-UNIPA-INAF-OAPA), S. Orlando (INAF-OAPA), G. Peres ( DSFA-UNIPA-INAF-OAPA), F. Favata(European Space Agency, 8-10 rue Mario Nikis, 75015 Paris, France), M. Miceli (DSFA-UNIPA-INAF-OAPA), J. Eisloffel ( Thüringer Landessternwarte, Tautenburg) 
 In the last decade, X-rays from jets have been discovered 
thanks to the unprecedented resolving power of Chandra. The first 
convincing evidence of X-ray jets came from HH2 (2000), HH154 following 
shortly thereafter. Whilemore sources were detected later, HH154 remains a unique source being 
the nearest and the most luminous among the nearest jets: the details of 
the relevant X-ray morphology can be studied to a level impossible with 
more distant objects.Our group has investigated the mechanisms of X-ray emission from jets 
both analyzing multi-epochs Chandra data of HH154 and developing numerical 
models of jets where X-rays are generated by jets shocking onto the 
circumstellar medium. The analysis of Chandra data of HH 154 in different 
epochs allowed us to study for the first time the morphology and the 
evolution of the X-ray source on a time scale of 4years. We found that the source consists of an unresolved, point-like 
component with no detectable proper motion and an elongated component 
with a proper motion consistent with a shock moving away from the parent 
star.We present here the comparison between the Chandra observations of HH 
jets and our hydrodynamic model of a randomly ejected pulsed jet which 
reproduces the knotty morphology observed.