|Tidal Tales of Dark Gas: Searching for [CII] in CO-Deficient Star Forming Tidal Tails
|How is star formation in tidal debris affected by gas properties? To probe the molecular gas properties of 3 tidal tail regions, we propose to use the PACS spectrometer on Herschel to observe the [CII] 158 micron line. Two particular tidal tail regions of interest are Clump II in the M81 group and the western tail of NGC 2782. These two regions are HI-rich and have young blue stars or star clusters detected in optical broadband and narrowband H-alpha imaging; however, observations of CO 1-0 show non-detections down to low limits. In contrast to these two regions, the base of the eastern tail of NGC 2782 is rich in HI and CO and has young star clusters. Although the non-detection of CO suggests that there is no molecular gas in Clump II and NGC 2782W, we expect the molecular gas to have a higher fraction of dark gas or mostly unobservable molecular hydrogen and C+. One way to observe this dark gas is to use the far infrared fine structure line of [CII] at 158 microns. Using these [CII] observations and previous data in optical, near-infrared, submillimeter, and radio, we will compare the measurements of gas and young stars in Clump II and NGC 2782W to those in NGC 2782E to examine the dependence of star formation in tidal tail regions on gas properties.
|Tidal Tails of Minor Mergers. II. Comparing Star Formation in the Tidal Tails of NGC 2782 . Knierman Karen A. et al. . The Astrophysical Journal, Volume 774, Issue 2, article id. 125, 20 pp. (2013). . 774 . 10.1088/0004-637X/774/2/125 . 2013ApJ...774..125K ,
|Herschel was launched on 14 May 2009! It is the fourth 'cornerstone' mission in the ESA science programme. With a 3.5 m Cassegrain telescope it is the largest space telescope ever launched. It is performing photometry and spectroscopy in approximately the 55-671 µm range, bridging the gap between earlier infrared space missions and groundbased facilities.
|Publisher And Registrant
|European Space Agency
|European Space Agency, 2012, OT1_kknierma_1, SPG v14.2.0. https://doi.org/10.5270/esa-qp3n6fc