This Scandinavian quintet stars some of the most exciting and flexible players in the revitalized Swedish and Norwegian jazz scenes–they can jump from free improv to postbop or electronics-augmented settings without breaking a sweat. But in the context of Atomic, the group’s three composers–reedist Fredrik Ljungkvist, pianist Havard Wiik, and trumpeter Magnus Broo–take inspiration mostly from the early days of American free jazz, like Ornette Coleman’s deceptively simple Atlantic recordings or the inside-out brilliance of mid-60s Blue Note works by the likes of Andrew Hill, Jackie McLean, and Grachan Moncur III, on which brooding harmonics collided with indelible, complex melodies. The matter-of-fact versatility and vivacity of their playing gets panoramic exposure on last year’s The Bikini Tapes (Jazzland), a three-CD document drawn from seven live dates in Norway in 2004. Some tunes, like Ljungkvist’s episodic “Kerosene,” appear twice on the set–and not only do the solos change from performance to performance, but the arrangements have enough leeway built in to let the group bring something new each time. The killer rhythm section–bassist Ingebrigt Haaker Flaten, who’s currently living in Chicago, and drummer Paal Nilssen-Love–gives the music contemporary muscle, so that despite its debt to a stack of 40-year-old LPs Atomic sounds as vital as anything in jazz these days.

Atomic is in town through the weekend and its members are scheduled to play in a bunch of collaborative contexts, starting with a Hideout gig featuring Atomic members along with reedist Ken Vandermark, bassist Kent Kessler, trombonist Jeb Bishop, and the great Swedish vibist Kjell Nordeson; see Wednesday for more info on that show. On Friday, April 21, and Saturday, April 22, Atomic will play with Vandermark’s group School Days (which includes Nordeson) at the Green Mill, 4802 N. Broadway, and the shows will be recorded for an album on Okka Disk; call 773-878-5522 for more info. And on Sunday, April 23, the Hungry Brain (2319 W. Belmont) will host a show starting with a sextet including Broo, Flaten, reedist Dave Rempis, cellist Fred Lonberg-Holm, keyboardist Jim Baker, and drummer Tim Daisy, followed by a quintet including Ljungkvist, Wiik, Kessler, reedist Jason Stein, and drummer Michael Reed; call 773-935-2118 for more info. Thu 4/20, 9 PM, Elastic, 2830 N. Milwaukee, 773-862-3616, donation requested.