Letter to the Editor

A Herschel study of the properties of starless cores in the Polaris Flare dark cloud region using PACS and SPIRE^*

¹ School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff, CF243AA, UK
² Laboratoire AIM, CEA/DSM-CNRS-Université Paris Diderot, IRFU/ Service d'Astrophysique, C.E. Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette, France
³ INAF-IFSI, Fosso del Cavaliere 100, 00133 Roma, Italy
⁴ IAS, Université Paris-Sud, Bât. 121, 91405 Orsay, France
⁵ LAM/OAMP, Université de Provence, 13388 Marseille, France
⁶ CESR, 9 Avenue du Colonel Roche, BP 4346, 31029 Toulouse, France
⁷ CDS, Observatoire de Strasbourg, 11 rue de l'Université, 67000 Strasbourg, France
⁸ IRAM, 300 rue de la Piscine, Domaine Universitaire, 38406 Saint Martin d'Héres, France
⁹ Herzberg Institute of Astrophysics, Department of Physics and Astronomy, University of Victoria, Victoria, Canada
¹⁰ NAOC, Chinese Academy of Sciences, A20 Datun Road, Chaoyang District, Beijing 100012, PR China
¹¹ CITA, University of Toronto, 60 St George Street, Toronto, Ontario, M5S 3H8, Canada
¹² Department of Astronomy, Stockholm University, AlbaNova University Center, 10691 Stockholm, Sweden
¹³ UKATC, Royal Observatory, Blackford Hill, Edinburgh, EH93HJ, UK
¹⁴ INAF, Largo Enrico Fermi 5, 50125 Firenze, Italy
¹⁵ RAL, Chilton, Didcot, OX110NL, UK
¹⁶ Dept. of Physics & Astronomy, Open University, Milton Keynes MK7 6AA, UK
¹⁷ Dept. of Physics & Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1, Canada

Received: 31 March 2010
Accepted: 10 May 2010

Abstract

The Polaris Flare cloud region contains a great deal of extended emission. It is at high declination and high Galactic latitude. It was previously seen strongly in IRAS Cirrus emission at 100 microns. We have detected it with both PACS and SPIRE on Herschel. We see filamentary and low-level structure. We identify the five densest cores within this structure. We present the results of a temperature, mass and density analysis of these cores. We compare their observed masses to their virial masses, and see that in all cases the observed masses lie close to the lower end of the range of estimated virial masses. Therefore, we cannot say whether they are gravitationally bound prestellar cores. Nevertheless, these are the best candidates to be potential prestellar cores in the Polaris cloud region.