VISION − Vienna survey in Orion

I. VISTA Orion A Survey^⋆,⋆⋆

¹ Department of Astrophysics, University of Vienna, Türkenschanzstrasse 17, 1180 Wien, Austria
e-mail: stefan.meingast@univie.ac.at
² Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile
³ University of Milan, Department of Physics, via Celoria 16, 20133 Milan, Italy
⁴ CENTRA, Instituto Superior Tecnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal
⁵ Universidade do Porto, Departamento de Engenharia Física da Faculdade de Engenharia, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal
⁶ Centro de Astrobiología, INTA-CSIC, Depto Astrofísica, PO Box 78, 28691 Villanueva de la Cañada, Madrid, Spain
⁷ Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
⁸ Max-Planck-Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
⁹ Astronomy Department, University of Florida, Gainesville, FL 32611, USA
¹⁰ SIM/CENTRA, Faculdade de Ciencias de Universidade de Lisboa, Ed. C8, Campo Grande, 1749-016 Lisboa, Portugal
¹¹ European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
¹² Instituto de Astronomía, UNAM, Ensenada, CP 22860, Baja California, Mexico

Received: 10 August 2015
Accepted: 1 December 2015

Abstract

Context. Orion A hosts the nearest massive star factory, thus offering a unique opportunity to resolve the processes connected with the formation of both low- and high-mass stars. Here we present the most detailed and sensitive near-infrared (NIR) observations of the entire molecular cloud to date.

Aims. With the unique combination of high image quality, survey coverage, and sensitivity, our NIR survey of Orion A aims at establishing a solid empirical foundation for further studies of this important cloud. In this first paper we present the observations, data reduction, and source catalog generation. To demonstrate the data quality, we present a first application of our catalog to estimate the number of stars currently forming inside Orion A and to verify the existence of a more evolved young foreground population.

Methods. We used the European Southern Observatory’s (ESO) Visible and Infrared Survey Telescope for Astronomy (VISTA) to survey the entire Orion A molecular cloud in the NIR J,H, and K_S bands, covering a total of ~18.3 deg². We implemented all data reduction recipes independently of the ESO pipeline. Estimates of the young populations toward Orion A are derived via the K_S-band luminosity function.

Results. Our catalog (799 995 sources) increases the source counts compared to the Two Micron All Sky Survey by about an order of magnitude. The 90% completeness limits are 20.4, 19.9, and 19.0 mag in J,H, and K_S, respectively. The reduced images have 20% better resolution on average compared to pipeline products. We find between 2300 and 3000 embedded objects in Orion A and confirm that there is an extended foreground population above the Galactic field, in agreement with previous work.

Conclusions. The Orion A VISTA catalog represents the most detailed NIR view of the nearest massive star-forming region and provides a fundamental basis for future studies of star formation processes toward Orion.