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A case of a 44-year-old man presenting with a family history of LMNA mutation and cardiac symptoms (dizziness, weakness, palpitations, and shortness of breath) congruent with dilated cardiomyopathy. Genetic testing revealed a novel likely pathogenic mutation of the LMNA gene (c.513G>A, exon 2) not previously associated with dilated cardiomyopathy, and the patient underwent guideline direct treatment for dilated cardiomyopathy. In patients with LMNA mutations, VTA risk should be calculated to determine the need for prophylactic ICD placement.

Despite the Milky Way's proximity to us, our knowledge of its dark matter halo is fairly limited, and there is still considerable uncertainty in its halo mass. Many past techniques have been limited by assumptions such as the Galaxy being in dynamical equilibrium as well as nearby galaxies being true satellites of the Galaxy, and/or the need to find large samples of Milky Way analogs in simulations.Here, we propose a new technique based on neural networks that obtains high precision (

The merger timescales of isolated low-mass pairs (10 ^8 < M _* < 5 × 10 ^9 M _⊙ ) on cosmologically motivated orbits have not yet been studied in detail, though isolated high-mass pairs (5 × 10 ^9 < M _* < 10 ^11 M _⊙ ) have been studied extensively. It is common to apply the same separation criteria and expected merger timescales of high-mass pairs to low-mass systems, however, it is unclear if their merger timescales are similar, or if they evolve similarly with redshift. We use the Illustris TNG100 simulation to quantify the merger timescales of isolated low-mass and high-mass major pairs as a function of cosmic time, and explore how different selection criteria impact the mass and redshift dependence of merger timescales. In particular, we present a physically motivated framework for selecting pairs via a scaled separation criterion, wherein pair separations are scaled by the virial radius of the primary’s Friends-of-Friends (FoF) group halo ( r _sep < 1 R _vir ). Applying these scaled separation criteria yields equivalent merger timescales for both mass scales at all redshifts. Alternatively, static physical separation selections applied equivalently to all galaxy pairs at all redshifts lead to a difference in merger rate of up to ∼1 Gyr between low- and high-mass pairs, particularly for r _sep < 150 kpc. As a result, applying the same merger timescales to physical-separation-selected pairs will lead to a bias that systematically overpredicts low-mass galaxy merger rates.

Understanding the physical mechanism behind the formation of a corotating thin plane of satellite galaxies, like the one observed around the Milky Way (MW), has been challenging. The perturbations induced by a massive satellite galaxy, like the Large Magellanic Cloud (LMC), provide valuable insight into this problem. The LMC induces an apparent corotating motion in the outer halo by displacing the inner regions of the halo with respect to the outer halo. Using the Latte suite of Feedback In Realistic Environments cosmological simulations of MW-mass galaxies, we confirm that the apparent motion of the outer halo induced by the infall of a massive satellite changes the observed distribution of orbital poles of outer-halo tracers, including satellites. We quantify the changes in the distribution of orbital poles using the two-point angular correlation function and find that all satellites induce changes. However, the most massive satellites with pericentric passages between ≈30 and 100 kpc induce the largest changes. The best LMC-like satellite analog shows the largest change in orbital pole distribution. The dispersion of orbital poles decreases by 20° during the first two pericentric passages. Even when excluding the satellites brought in with the LMC-like satellite, there is clustering of orbital poles. These results suggest that in the MW, the recent pericentric passage of the LMC should have changed the observed distribution of orbital poles of all other satellites. Therefore, studies of kinematically coherent planes of satellites that seek to place the MW in a cosmological context should account for the existence of a massive satellite like the LMC.

We have determined the proper motions (PMs) of 12 dwarf galaxies in the Local Group (LG), ranging from the outer Milky Way (MW) halo to the edge of the LG. We used the Hubble Space Telescope (HST) as the first and Gaia as the second epoch using the GaiaHub software. For Leo A and Sag DIG, we also used multi-epoch HST measurements relative to background galaxies. Orbital histories derived using these PMs show that two-thirds of the galaxies in our sample are on first infall with >90% certainty. The observed star formation histories of these first-infall dwarfs are generally consistent with infalling dwarfs in simulations. The remaining four galaxies have crossed the virial radius of either the MW or M31. When we compare their star formation (SF) and orbital histories we find tentative agreement between the inferred pattern of SF with the timing of dynamical events in the orbital histories. For Leo I, SF activity rises as the dwarf crosses the MW’s virial radius, culminating in a burst of SF shortly before pericenter (≈1.7 Gyr ago). The SF then declines after pericenter, but with some smaller bursts before its recent quenching (≈0.3 Gyr ago). This shows that even small dwarfs like Leo I can hold onto gas reservoirs and avoid quenching for several gigayears after falling into their host, which is longer than generally found in simulations. Leo II, NGC 6822, and IC 10 are also qualitatively consistent with this SF pattern in relation to their orbit, but more tentatively due to larger uncertainties.

We present deep Hubble Space Telescope photometry of 10 targets from Treasury Program GO-14734, including six confirmed ultrafaint dwarf (UFD) galaxies, three UFD candidates, and one likely globular cluster. Six of these targets are satellites of, or have interacted with, the Large Magellanic Cloud (LMC). We determine their structural parameters using a maximum-likelihood technique. Using our newly derived half-light radius ( r _h ) and V -band magnitude ( M _V ) values in addition to literature values for other UFDs, we find that UFDs associated with the LMC do not show any systematic differences from Milky Way UFDs in the magnitude–size plane. Additionally, we convert simulated UFD properties from the literature into the M _V – r _h observational space to examine the abilities of current dark matter (DM) and baryonic simulations to reproduce observed UFDs. Some of these simulations adopt alternative DM models, thus allowing us to also explore whether the M _V – r _h plane could be used to constrain the nature of DM. We find no differences in the magnitude–size plane between UFDs simulated with cold, warm, and self-interacting DM, but note that the sample of UFDs simulated with alternative DM models is quite limited at present. As more deep, wide-field survey data become available, we will have further opportunities to discover and characterize these ultrafaint stellar systems and the greater low surface-brightness universe.

Low-mass galaxy pair fractions are understudied, and it is unclear whether low-mass pair fractions evolve in the same way as more massive systems over cosmic time. In the era of JWST, Roman, and Rubin, selecting galaxy pairs in a self-consistent way will be critical to connect observed pair fractions to cosmological merger rates across all mass scales and redshifts. Utilizing the Illustris TNG100 simulation, we create a sample of physically associated low-mass (10 ^8 < M _* < 5 × 10 ^9 M _⊙ ) and high-mass (5 × 10 ^9 < M _* < 10 ^11 M _⊙ ) pairs between z = 0 and 4.2. The low-mass pair fraction increases from z = 0 to 2.5, while the high-mass pair fraction peaks at z = 0 and is constant or slightly decreasing at z > 1. At z = 0 the low-mass major (1:4 mass ratio) pair fraction is 4× lower than high-mass pairs, consistent with findings for cosmological merger rates. We show that separation limits that vary with the mass and redshift of the system, such as scaling by the virial radius of the host halo ( r _sep < 1 R _vir ), are critical for recovering pair fraction differences between low-mass and high-mass systems. Alternatively, static physical separation limits applied equivalently to all galaxy pairs do not recover the differences between low- and high-mass pair fractions, even up to separations of 300 kpc. Finally, we place isolated mass analogs of Local Group galaxy pairs, i.e., Milky Way (MW)–M31, MW–LMC, LMC–SMC, in a cosmological context, showing that isolated analogs of LMC–SMC-mass pairs and low-separation (