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Abstract We present new CO(2–1) observations (resolution ∼1″ = 460 pc) of the Coma cluster jellyfish galaxy NGC 4858 obtained from the ALMA-JELLY large program. Analyzing this data alongside complimentary Subaru Hαand Hubble Space Telescope (F600LP / F350LP) observations, we find numerous structural and kinematic features indicative of the effects from strong, inclined ram pressure, including an asymmetric inner gas tail. We estimate a highly inclined disk-wind angle of ${\varphi }_{\text{DW}}=75_{-27}^{+10}$. By subtracting a simple circular velocity model, we find (1): gas clumps that are being accelerated by ram pressure, and (2): signatures of gas clumps that had been previously pushed out of the disk but are now falling inward. We also discuss head-tail morphologies in star complexes within the stellar disk that appear to be ram pressure stripping (RPS)-influenced. Lastly, we compare this galaxy to state-of-the-art galaxy “wind tunnel” simulations. We find that this galaxy is one of the best nearby examples of strong and inclined ram pressure gas stripping, and of gas that is perturbed by ram pressure but not fully stripped and falls back. We emphasize the importance of torques due to ram pressure in highly inclined interactions, which help drive gas inward on the side rotating against the wind, contributing to the formation of asymmetric inner RPS tails. 

Abstract The cluster environment has been shown to affect the molecular gas content of cluster members, yet a complete understanding of this often subtle effect has been hindered due to a lack of detections over the full parameter space of galaxy star formation rates (SFRs) and stellar masses. Here, we stack CO(2–1) spectra ofz ∼ 1.6 cluster galaxies to explore the average molecular gas fractions of galaxies both at lower mass (log(M_*/M_⊙) ∼ 9.6) and further below the star-forming main sequence (SFMS; ΔMS ∼ −0.9) than other literature studies; this translates to a 3σgas mass limit of  ∼7 × 10⁹M_⊙for stacked galaxies below the SFMS. We divide our sample of 54z ∼ 1.6 cluster galaxies, derived from the Spitzer Adaptation of the Red-Sequence Cluster Survey, into nine groupings, for which we recover detections in 8. The average gas content of the full cluster galaxy population is similar to coeval field galaxies matched in stellar mass and SFR. However, when further split by CO-undetected and CO-detected, we find that galaxies below the SFMS have statistically different gas fractions from the field scaling relations, spanning deficiencies to enhancements from 2σbelow to 3σabove the expected field gas fractions, respectively. These differences betweenz= 1.6 cluster and field galaxies below the SFMS are likely due to environmental processes, though further investigation of spatially resolved properties and more robust field scaling relation calibration in this parameter space are required. 

Abstract. It is well known that the polar cap, delineated by the open–closed field line boundary (OCB),responds to changes in the interplanetary magnetic field (IMF).In general, the boundary moves equatorward when the IMF turns southward and contractspoleward when the IMF turns northward. However,observations of the OCB are spotty and limited in local time,making more detailed studies of its IMF dependence difficult.Here, we simulate five solar storm periods with the coupled model consisting of the OpenGeospace General Circulation Model (OpenGGCM) coupled with the Coupled Thermosphere IonosphereModel (CTIM) and the Rice Convection Model (RCM),i.e., the OpenGGCM-CTIM-RCM, to estimate the location and dynamics of the OCB.For these events, polar cap boundary location observations are also obtained from Defense MeteorologicalSatellite Program (DMSP) precipitation spectrograms and compared with the model output.There is a large scatter in the DMSP observations and in the model output.Although the model does not predict the OCB with high fidelity for every observation,it does reproduce the general trend as a function of IMF clock angle.On average, the model overestimates the latitude of the open–closed field line boundaryby 1.61∘. Additional analysis of the simulated polar cap boundary dynamics acrossall local times shows that the MLT of the largest polar cap expansion closely correlateswith the IMF clock angle, that the strongest correlation occurs when the IMF is southward, thatduring strong southward IMF the polar cap shifts sunward, and that the polar cap rapidlycontracts at all local times when the IMF turns northward.