A Catalog of OB Associations in the spiral galaxy NGC 300^*

¹ Universidad de Concepción, Departamento de Fisica, Casilla 160-C, Concepción, Chile e-mail: wgieren@coma.cfm.udec.cl
² Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa, Poland
³ Observatoire de Paris-Meudon DESPA, 92195 Meudon Cedex, France
⁴ European Southern Observatory, Casilla 19001, Santiago 19, Chile e-mail: pfouque@eso.org
⁵ Universidad de Chile, Departamento de Astronomia, Casilla 36D, Santiago, Chile e-mail: FredericPont@obs.unige.ch

Corresponding author: G. Pietrzyński, pietrzyn@hubble.cfm.udec.cl

Received: 2 January 2001
Accepted: 13 March 2001

Abstract

We present results of a search for OB associations in NGC 300. Using an automatic and objective method (PLC technique) 117 objects were found. Statistical tests indicate that our sample is contaminated by less than 10 detections due to random concentrations of blue stars. Spatial distributions of detected associations and H II regions are strongly correlated. The size distribution reveals a significant peak at about 60 μrad which corresponds to 125 parsecs if a distance modulus of 26.66 mag is assumed. Besides the objects with sizes corresponding to typical associations we also found several much larger objects. A second level application of our detection method revealed that most of these are composed of smaller subgroups, with sizes of about 100 pc.