Results are presented for [CII] 158 µm line fluxes observed with the Herschel PACS instrument in 112 sources with both starburst and AGN classifications, of which 102 sources have confident detections. Results are compared with midinfrared spectra from the Spitzer Infrared Spectrometer and with L ir from IRAS fluxes; AGN/starburst classifications are determined from equivalent width of the 6.2 µm PAH feature. It is found that the [CII] line flux correlates closely with the flux of the 11.3 µm PAH feature independent of AGN/starburst classification, log [f([CII] 158 µm)/f(11.3 µm PAH)] = -0.22 ± 0.25. It is concluded that [CII] line flux measures the photodissociation region associated with starbursts in the same fashion as the PAH feature. A calibration of star formation rate for the starburst component in any source having [CII] is derived comparing [CII] luminosity L([CII]) to L ir with the result that log SFR = log L([CII)]) -7.08 ± 0.3, for SFR in M ⊙ yr −1 and L([CII]) in L ⊙ . The decreasing ratio of L([CII]) to L ir in more luminous sources (the "[CII] deficit") is shown to be a consequence of the dominant contribution to L ir arising from a luminous AGN component because the sources with largest L ir and smallest L([CII])/L ir are AGN.

A summary is presented for 130 galaxies observed with the Herschel PACS instrument to measure fluxes for the [CII] 158 µm emission line. Sources cover a wide range of active galactic nucleus to starburst classifications, as derived from polycyclic aromatic hydrocarbon (PAH) strength measured with the Spitzer Infrared Spectrograph. Redshifts from [CII] and line to continuum strengths (equivalent width of [CII]) are given for the full sample, which includes 18 new [CII] flux measures. Calibration of L([CII)]) as a star formation rate (SFR) indicator is determined by comparing [CII] luminosities with mid-infrared [NeII] and [NeIII] emission line luminosities; this gives the same result as determining SFR using bolometric luminosities of reradiating dust from starbursts: log SFR = log L([CII)]) -7.0, for SFR in M ⊙ yr −1 and L([CII]) in L ⊙ . We conclude that L([CII]) can be used to measure SFR in any source to a precision of ∼ 50%, even if total source luminosities are dominated by an AGN component. The line to continuum ratio at 158 µm, EW([CII]), is not significantly greater for starbursts (median EW([CII]) = 1.0 µm) compared to composites and AGN (median EW([CII]) = 0.7 µm), showing that the far infrared continuum at 158 µm scales with [CII] regardless of classification. This indicates that the continuum at 158 µm also arises primarily from the starburst component within any source, giving log SFR = log νL ν (158 µm) -42.8 for SFR in M ⊙ yr −1 and νL ν (158 µm) in erg s −1 .

The sample of 379 extragalactic sources is presented that have mid-infrared, high resolution spectroscopy with the Spitzer Infrared Spectrograph (IRS) and also spectroscopy of the [C II] 158 µm line with the Herschel Photodetector Array Camera and Spectrometer (PACS). The emission line profiles of [Ne II] 12.81 µm, [Ne III] 15.55 µm, and [C II] 158 µm are presented, and intrinsic line widths are determined (full width half maximum of Gaussian profiles after instrumental correction). All line profiles together with overlays comparing positions of PACS and IRS observations are made available in the Cornell Atlas of Spitzer IRS Sources (CASSIS). Sources are classified from AGN to starburst based on equivalent widths of the 6.2 µm polycyclic aromatic hydrocarbon feature. It is found that intrinsic line widths do not change among classification for [C II], with median widths of 207 km s −1 for AGN, 248 km s −1 for composites, and 233 km s −1 for starbursts. The [Ne II] line widths also do not change with classification, but [Ne III] lines are progressively broader from starburst to AGN. A small number of objects with unusually broad lines or unusual redshift differences in any feature are identified.

This is an analysis of the dependence of the flare activity of the well known flare star UV Ceti on the linear distance between the components of this binary system. It is shown that its flaring activity clearly depends on the mutual distance of the components, while this kind of variability is not seen in isolated flare stars.

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