paper

Far-Infrared Line Imaging of the Starburst Ring in NGC 1097 with the Herschel/PACS Spectrometer

arXiv:1005.1611 · doi:10.1051/0004-6361/201014592

Abstract

NGC 1097 is a nearby SBb galaxy with a Seyfert nucleus and a bright starburst ring. We study the physical properties of the interstellar medium (ISM) in the ring using spatially resolved far-infrared spectral maps of the circumnuclear starburst ring of NGC 1097, obtained with the PACS spectrometer on board the Herschel Space Telescope. In particular, we map the important ISM cooling and diagnostic emission lines of [OI] 63 $I^¼$ m, [OIII] 88 $I^¼$ m, [NII] 122 $I^¼$ m, [CII] 158 $I^¼$ m and [NII] 205 $I^¼$ m. We observe that in the [OI] 63 $I^¼$ m, [OIII] 88 $I^¼$ m, and [NII] 122 $I^¼$ m line maps, the emission is enhanced in clumps along the NE part of the ring. We observe evidence of rapid rotation in the circumnuclear ring, with a rotation velocity of ~220 $k m s$ ^{-1} $(in c l ina t i o n u n cor r ec t e d) m e a s u r e d ina l l l in es . T h e [O I] 63$ Î¼ $m / [C I I] 158$ Î¼ $m r a t i o v a r i ess m oo t h l y t h r o ug h o u tt h ece n t r a l r e g i o n, an d i se nhan ce d o n t h e n or t h e a s t er n p a r t o f t h er in g, w hi c hma y in d i c a t e a s t r o n g er r a d ia t i o n f i e l d . T hi se nhan ce m e n t co in c i d es w i t h p e ak s in t h e [O I] 63$ Î¼ $man d [O I I I] 88$ Î¼ $mma p s . V a r ia t i o n so f t h e [N I I] 122$ Î¼ $m / [N I I] 205$ Î¼ $m r a t i ocor r es p o n d t o a r an g e in t h e i o ni z e d g a s d e n s i t y b e tw ee n 150 an d 400 c m$ ^{-3}$.

Accepted for publication on the A&A Herschel Special Issue