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Astron. Astrophys. 357, 219-224 (2000)

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ISOCAM observations of the Chamaeleon I dark cloud * ** ***

P. Persi 1, A.R. Marenzi 1, G. Olofsson 2, A.A. Kaas 2,12, L. Nordh 2, M. Huldtgren 2, A. Abergel 3, P. André 4, S. Bontemps 2,5, F. Boulanger 3, M. Burggdorf 6, M.M. Casali 7, C.J. Cesarsky 4, E. Copet 8, J. Davies 9, E. Falgarone 10, T. Montmerle 4, M. Perault 10, T. Prusti 6, J.L. Puget 3 and F. Sibille 11

1 Istituto Astrofisica Spaziale, CNR, Area di Ricerca Tor Vergata, Via del Fosso del Cavaliere, 00133 Roma, Italy (persi@saturn.ias.)
2 Stockholm Observatory, 133 36 Saltsjöbaden, Sweden
3 IAS, Université Paris XI, Orsay, France
4 Service d'Astrophysique, CEA Saclay, Gif-sur-Yvette, France
5 Observatoire de Bordeaux, Floirac, France
6 ISO Data Centre, ESA Astrophysics Division, Villafranca del Castillo, Spain
7 Royal Observatory, Blackford Hill, Edinburgh, UK
8 DESPA, Observatoire Paris-Meudon, France
9 Joint Astronomy Centre, Hawaii, USA
10 ENS Radioastronomie, Paris, France
11 Observatoire de Lyon, France
12 Astrophysics Division of ESA, ESTEC, 2201 AZ Noordwijk, The Netherlands

Received 3 December 1999 / Accepted 29 February 2000


We present the results of an ISOCAM survey of the Chamaeleon I dark cloud conducted in two broad-band filters at 6.7 and 14.3 [FORMULA]. In an area of 0.59 sq.deg. we have detected a total of 282 mid-IR sources with 103 sources observed in both filters. Combining the ISOCAM observations with the I, J, and Ks data obtained with DENIS, we have found 108 pre-main-sequence (PMS) stars in the region, of which 34 were previously unidentified. Several of these newly discovered young stellar objects are relatively faint suggesting a population in Cha I of very low mass objects that probably includes brown dwarfs in their early contraction phases. Finally, most of the PMS stars show the spectral index computed between 2.2 and 14.3 [FORMULA] typical of Class II sources. The luminosity function (LF) derived for our detected PMS stars is discussed.

Key words: stars: formation – stars: low-mass, brown dwarfs – stars: luminosity function, mass function – stars: pre-main sequence – infrared: stars

* ISO is an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) and with the participation of ISAS and NASA.
** Tables 1 and 2 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr ( or via http://cdsweb.u-strasbg.fr/Abstract.html
*** Tables 3 and 4 are only available with the on-line publication at http://link.springer.de/link/service/journals/00230/

Send offprint requests to: P. Persi

Correspondence to: Istituto Astrofisica Spaziale, CNR, Area di Ricerca Tor Vergata, Via del Fosso del Cavaliere, 00133, Roma, Italy

© European Southern Observatory (ESO) 2000

Online publication: May 3, 2000