Performance and calibration of the NIKA camera at the IRAM 30 m telescope

A. Catalano (1) , M. Calvo (2) , N. Ponthieu (3) , R. Adam (1) , A. Adane (4) , P. Ade , P. Andre , A. Beelen (5) , B. Belier (6) , A. Benoît (7) , A. Bideaud , N. Billot , N. Boudou (7) , O. Bourrion (1) , G. Coiffard (4) , B. Comis (1) , A. d'Addabbo (7) , F. -X. Desert (3) , S. Doyle , J. Goupy (7) , C. Kramer , S. Leclercq (4) , J.F. Macias-Perez (1) , J. Martino (5) , P. Mauskopf , F. Mayet (1) , A. Monfardini (7) , F. Pajot (5) , E. Pascale , L. Perotto (1) , V. Reveret , L. Rodriguez , G. Savini , K. Schuster (4) , A. Sievers , C. Tucker , R. Zylka (4)

1 LPSC - Laboratoire de Physique Subatomique et de Cosmologie
2 NEEL - Cryo - Cryogénie
3 IPAG - Institut de Planétologie et d'Astrophysique de Grenoble
4 IRAM - Institut de RadioAstronomie Millimétrique
5 IAS - Institut d'astrophysique spatiale
6 IEF - Institut d'électronique fondamentale
7 NEEL - HELFA - Hélium : du fondamental aux applications

The New IRAM KID Array (NIKA) instrument is a dual-band imaging camera operating with Kinetic Inductance Detectors (KID) cooled at 100 mK. NIKA is designed to observe the sky at wavelengths of 1.25 and 2.14 mm from the IRAM 30m telescope at Pico Veleta with an estimated resolution of 13 arcsec and 18 arcsec respectively. This work presents the performance of the NIKA camera prior to its opening to the astrophysical community as an IRAM common user facility in early 2014. NIKA is a test-bench for the final NIKA2 instrument to be installed at the end of 2015. The last NIKA observation campaigns on November 2012 and June 2013 have been used to evaluate this performance and to improve the control of systematic effects. We discuss here the dynamical tuning of the readout electronics to optimize the KID working point with respect to background changes and the new technique of atmospheric absorption correction. These modifications improve significantly the overall linearity, sensitivity and absolute calibration performance of NIKA. This is proved on observations of point-like sources for which we obtain a best sensitivity (averaged over all valid detectors) of 40 and 14 mJy.s^1/2 for optimal weather conditions for the 1.25 and 2.14 mm arrays, respectively. NIKA observations of well known extended sources (DR21 complex and the Horsehead nebula) are presented. This performance makes the NIKA camera a competitive astrophysical instrument.

Domaines: Instrumentation et méthodes pour l'astrophysique [astro-ph.IM]; Instrumentation et méthodes pour l'astrophysique [astro-ph.IM]

A. Catalano, M. Calvo, N. Ponthieu, R. Adam, A. Adane, et al.. Performance and calibration of the NIKA camera at the IRAM 30 m telescope. Astronomy and Astrophysics - A&A, 2014, 569, pp.A9. ⟨10.1051/0004-6361/201423557⟩. ⟨in2p3-00943125⟩