Since the late 90s there’s been a deluge of thrilling jazz, improvisational, and experimental music pouring out of Scandinavia, and much of it runs hot, in marked contrast to the icily contemplative stuff exported from that region by ECM during the 70s. Chicagoans have had numerous opportunities to hear the new sounds thanks to Ken Vandermark, who’s drafted top Norwegian and Swedish talent for groups like School Days, the Territory Band, and the Peter Brotzmann Chicago Tentet. Three members of this cohort–drummer Paal Nilssen-Love, reedist Fredrik Ljungkvist, and bassist Ingebrigt Haker-Flaten–also belong to Atomic, a superb jazz-oriented quintet with two albums on Norway’s Jazzland label, Feet Music and Boom Boom, and a brand-new collaboration with School Days on Okka Disk, Nuclear Assembly Hall. Atomic’s improvisations are propelled by collectively composed tunes steeped in the inside-out sound and dark, postbop melodies of late-60s Blue Note sides by the likes of Sam Rivers, Jackie McLean, and Grachan Moncur III. But the group is no throwback: Nilssen-Love drives the group with a thoroughly contemporary ferocity, maintaining an insistent pulse while carving out marvelous polyrhythms and explosive accents all over his kit. Pianist Havard Wiik frequently counterbalances the tart angularity of the lines played by Ljungkvist and trumpeter Magnus Broo with a brooding melancholy reminiscent of Bill Evans. While rooted in jazz, Atomic is casual about genre boundaries, offering a stately take on Paul Hindemith’s “Praeludium” and a gorgeous reading of Radiohead’s “Pyramid Song.” For this show Atomic (making its Chicago debut) and the Vandermark 5 will play a set apiece, then join forces for a third. $12. Friday, June 11, 9 PM, and Saturday, June 12, 8 PM, Green Mill, 4802 N. Broadway; 773-878-5552.