EDP Sciences
Free access
Volume 410, Number 2, November I 2003
Page(s) L21 - L24
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:20031443

A&A 410, L21-L24 (2003)
DOI: 10.1051/0004-6361:20031443


The first detection of Far-Infrared emission associated with an extended HI disk. The case of NGC 891

C. C. Popescu1, 2 and R. J. Tuffs1

1  Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
    e-mail: Cristina.Popescu@mpi-hd.mpg.de;
    e-mail: Richard.Tuffs@mpi-hd.mpg.de
2  Research Associate, The Astronomical Institute of the Romanian Academy, Bucharest, Romania

(Received 15 August 2003 / Accepted 16 September 2003 )

Spiral galaxies in the local universe are commonly observed to be embedded in extended disks of neutral hydrogen - the so called "extended HI disks". Based on observations made using the ISOPHOT instrument on board the Infrared Space Observatory, we report the first detection of cold dust in the extended HI disk of a spiral galaxy. The detection was achieved through a dedicated deep Far-Infrared observation of a large field encompassing the entire HI disk of the edge-on spiral galaxy NGC 891. Our discovery indicates that the extended HI disk of NGC 891 is not primordial in origin.

Key words: galaxies: spiral -- galaxies: structure -- galaxies: evolution -- ISM: dust -- infrared: continuum

Offprint request: C. C. Popescu, Cristina.Popescu@mpi-hd.mpg.de

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