1 Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA; den- nis.zaritsky@gmail.com 2 Astronomy Division, Department of Physics, P.O. Box 3000, FI-90014 University of Oulu, Finland 3 Finnish Centre of Astronomy with ESO (FINCA), Univer- sity of Turku, V ̈ais ̈al ̈antie 20, FI-21500, Piikkio ̈, Finland 4 Vassar College, Dept. of Physics and Astronomy, Pough- keepsie, NY 12604, USA 5 Aix Marseille Universit ́e, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, 13388, Marseille, France 6 Instituto de Astrof ́ısica de Canarias, V ́ıa L ́acteas 38205 La Laguna, Spain 7 Departamento de Astrof ́ısica, Universidad de La Laguna, 38206, La Laguna, Spain 8 IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY 10598, USA 9 European Southern Observatory, Casilla 19001, Santaigo 19, Chile 10 Departamento de Astrof ́ısica, Universidad Complutense de Madrid, Madrid, Spain 11 MMT Observatory, P.O. Box 210065, Tucson, AZ 85721, USA 12 The Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101, USA 13 ESA Fellow, European Space Agency (ESTEC), Keplerlaan 1, 2200 AG Noordwijk, The Netherlands 14 National Radio Astronomy Observatory/ NAASC, 520 Edgemont Road, Charlottesville, VA 22903, USA 15 Spitzer Science Center, 1200 East California Boulevard, Pasadena, CA 91125, USA 16 Max-Planck-Institut fu ̈r Astronomie, K ̈onigstu ̈hl 17 D- 69117, Heidelberg, Germany 17 Observatorio do Valongo, Universidade Federal de Rio de Janeiro, Ladeira Pedro Antnio, 43, Sau ́de CEP 20080-090, Rio de Janeiro-RJ-Brazil 18 California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA 19 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA

1 National Radio Astronomy Observatory / NAASC, 520 Edgemont Road, Charlottesville, VA 22903 2 DepartamentodeAstrof ́ısica,UniversidadComplutensede Madrid, Madrid 28040, Spain 3 Max-Planck-Institut fu ̈r Astronomie, K ̈onigstuhl 17, 69117 Heidelberg, Germany 4 Aix Marseille Universite, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, 13388, Marseille, France 5 Department of Physical Sciences/Astronomy Division, Univer- sity of Oulu, FIN-90014, Finland 6 Vassar College, Dept. of Physics and Astronomy, Poughkeep- sie, NY 12604 7 IBM Research Division, T.J. Watson Research Center, York- town Hts., NY 10598 8 Instituto de Astrof ́ısica de Canarias, 38205 La Laguna, Spain 9 DepartamentodeAstrof ́ısica,UniversidaddeLaLaguna, 38206 La Laguna, Spain 10 European Southern Observatory, Casilla 19001, Santiago 19, Chile 11 University of Arizona, 933 N. Cherry Ave, Tucson, AZ 85721 12 The Observatories, Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 13 European Space Agency, ESTEC, Keplerlaan 1, 2200 AG, Noordwijk, the Netherlands 14 Astrophysics, Cosmology and Gravity Centre, Department of Astronomy, University of Cape Town, Private Bag X3, Ronde- bosch 7701, South Africa 15 Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul 151-742, Korea 16 Finnish Centre for Astronomy with ESO (FINCA), University of Turku 17 Observatorio do Valongo, Universidade Federal de Rio de Janeiro, Ladeira Pedro Antonio, 43, Saude CEP 20080-090, Rio de Janeiro - RJ - Brasil 18 Florida Institute of Technology, Melbourne, FL 32901 19 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218

(1) IA-UNAM, Mexico, (2) IAC, Spain, (3) ULL, Spain, (4) Kapteyn Instituut, Nederlands

(1) IAC, (2) University of La Laguna, (3) INAF--Osservatorio Astronomico di Teramo, (4) ESO Chile.

1 Actinium Chemical Research srl, Via Casilina 1626A, 00133 Rome, Italy E - Mail : franco.cataldo@fastwebnet.it 2 Osservatorio Astrofisico di Catania, Via S. Sofia 78, 95123 Catania, Italy ; 3 National Center for Astronomy, KACST, P.O. Box 6086, Riyad 11442 Saudi Arabia 4 Istituto di Metodologie Chimiche, CNR, Via Salaria Km 29,300, Monterotondo Stazione 00016, Rome, Italy 5 Instituto de Astrofisica de C anarias, Via Lactea s/n, 38200 La Laguna, Tenerife, Spain Universidad de La Laguna, Spain