Inside the double affine Hecke algebra Hn,q,Οβ of type
GLnβ, we define a subalgebra Hglnβ that may be
thought of as a q-deformation of the degree zero part of the corresponding
rational Cherednik algebra. We prove that the algebra
Hglnβ is a flat Ο-deformation of the semi-direct
product of the group algebra CSnβ of the symmetric group
with the image of the Drinfeld-Jimbo quantum group Uqβ(glnβ) under
the q-oscillator (Jordan-Schwinger) representation. We find all the defining
relations and an explicit PBW basis for the algebra
Hglnβ. We describe its centre and establish a double
centraliser property. Further, we develop the connection with integrable
systems introduced by van Diejen, which we also generalise.Comment: 46 page