Volume 395, Number 2, November IV 2002
|Page(s)||663 - 667|
|Published online||14 November 2002|
Extending the limits of globule detection *
ISOPHOT Serendipity Survey observations of interstellar clouds II
Helsinki University Observatory, PO Box 14, 00014 University of Helsinki, Finland
2 Department of Astronomy, Loránd Eötvös University, Pázmány Péter sétány 1/a, 1117 Budapest, Hungary
3 Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
4 Konkoly Observatory, Budapest, PO Box 67, 1525, Hungary
5 IRAM, Avenida Divina Pastora 7, N.C., 18012 Granada, Spain
Corresponding author: L. V. Tóth, firstname.lastname@example.org
Accepted: 2 September 2002
Small isolated clouds were discovered by the ISOPHOT 170 μm Serendipity Survey (ISOSS) as faint MJy sr-1 FIR sources. One of them is ISOSS J20246+6540, a cold ( K) pointlike ISOSS source without an IRAS pointsource counterpart. In the Digitized Sky Survey B band it is seen as a 3´size bipolar nebulosity with an average excess DSS blue band surface brightness of 8% of the background's photographical density. The CO column density distribution determined by multi-isotopic, multi-level CO measurements with the IRAM-30 m telescope agrees well with the optical appearance. An average hydrogen column density of ≈ 1021 cm-2 was derived from both the FIR and CO data. Using a kinematic distance estimate of 400 pc the NLTE modelling of the CO, HCO+, and CS measurements gives a peak density of ≈ 104 cm-3. The multiwavelength data characterise ISOSS 20246+6540 as a representative of a class of globules which has not been discovered so far due to their small angular size and low 100 μm brightness. A significant overabundance of 13CO is found COC18O. This is likely due to isotope selective chemical processes.
Key words: ISM: clouds / dust, extinction / ISM: molecules / Infrared: ISM: / Surveys
© ESO, 2002
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.