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Congress has the authority to arrest and imprison those found in Contempt. The power extends throughout the United States and is an inherent power (does not depend upon legislated act)

If found in Contempt the person can be arrested under a warrant of the Speaker of the House of Representatives or President of the Senate, by the respective Sergeant at Arms.

Statutory criminal contempt is an alternative to inherent contempt.

Under the inherent contempt power Congress may imprison a person for a specific period of time or an indefinite period of time, except a person imprisoned by the House of Representatives may not be imprisoned beyond adjournment of a session of Congress.

Imprisonment may be coercive or punitive.

Some references

[1] Joseph Story’s Commentaries on the Constitution, Volume 2, § 842
http://press-pubs.uchicago.edu/founders/print_documents/a1_5s21.html

[2] Anderson v. Dunn - 19 U.S. 204 - “And, as to the distance to which the process might reach, it is very clear that there exists no reason for confining its operation to the limits of the District of Columbia; after passing those limits, we know no bounds that can be prescribed to its range but those of the United States.”
http://supreme.justia.com/cases/federal/us/19/204/case.html

[3] Jurney v. MacCracken, 294 U.S. 125
http://supreme.justia.com/cases/federal/us/294/125/case.html
73rd Cong., 78 Cong. Rec. 2410 (1934)
https://archive.org/details/congressionalrec78aunit

[4] McGrain v. Daugherty, 273 U.S. 135 - Under a warrant issued by the President of the Senate the Deputy to the Senate Sergeant at Arms arrested at Cincinnati, Ohio, Mally S. Daugherty, who had been twice subpoenaed by the Senate and twice failed to appear.
http://supreme.justia.com/cases/federal/us/273/135/case.html

[5] Rules of the House of Representatives, Rule IV Duties of the Sergeant at Arms - [] execute the commands of the House, and all processes issued by authority thereof, directed to him by the Speaker.
http://www.gpo.gov/fdsys/pkg/HMAN-105/pdf/HMAN-105-pg348.pdf

[6] An analysis of Congressional inquiry, subpoena, and enforcement
http://www.constitutionproject.org/documents/when-congress-comes-calling-a-primer-on-the-principles-practices-and-pragmatics-of-legislative-inquiry/