ﻻ يوجد ملخص باللغة العربية
We present SOFIA/FIFI-LS observations of the [CII] 158${mu}$m cooling line across the nearby spiral galaxy NGC 6946. We combine these with UV, IR, CO, and H I data to compare [CII] emission to dust properties, star formation rate (SFR), H$_2$, and HI at 560pc scales via stacking by environment (spiral arms, interarm, and center), radial profiles, and individual, beam-sized measurements. We attribute $73%$ of the [CII] luminosity to arms, and $19%$ and $8%$ to the center and interarm region, respectively. [CII]/TIR, [CII]/CO, and [CII]/PAH radial profiles are largely constant, but rise at large radii ($gtrsim$8kpc) and drop in the center ([CII] deficit). This increase at large radii and the observed decline with the 70${mu}$m/100${mu}$m dust color are likely driven by radiation field hardness. We find a near proportional [CII]-SFR scaling relation for beam-sized regions, though the exact scaling depends on methodology. [CII] also becomes increasingly luminous relative to CO at low SFR (interarm or large radii), likely indicating more efficient photodissociation of CO and emphasizing the importance of [CII] as an H$_2$ and SFR tracer in such regimes. Finally, based on the observed [CII] and CO radial profiles and different models, we find ${alpha}_{CO}$ to increase with radius, in line with the observed metallicity gradient. The low ${alpha}_{CO}$ (galaxy average $lesssim2,M_{sun},pc^{-2},(K,km,s^{-1})^{-1}$) and low [CII]/CO ratios ($sim$400 on average) imply little CO-dark gas across NGC 6946, in contrast to estimates in the Milky Way.
We present the first complete, velocity-resolved [CII] 158um image of the M51 grand-design spiral galaxy, observed with the upGREAT instrument on SOFIA. [CII] is an important tracer of various phases of the interstellar medium (ISM), including ionize
While the CO(1-0) transition is often used to deduce the total molecular hydrogen in galaxies, it is challenging to detect in low metallicity galaxies, in spite of the star formation taking place. In contrast, the [CII] 158 micron line is relatively
The current paradigm of Galactic Center (GC) gas motions and star formation envisions sequential star formation in streams of gas as they pass near the supermassive black hole, Sgr A*. This is based on the relative positions of dense molecular clouds
New deep VLA D array HI observations of the highly inclined nearby spiral galaxy NGC 2683 are presented. Archival C array data were processed and added to the new observations. To investigate the 3D structure of the atomic gas disk, we made different
Star formation induced by a spiral shock wave, which in turn is generated by a spiral density wave, produces an azimuthal age gradient across the spiral arm, which has opposite signs on either side of the corotational resonance. An analysis of the sp