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The stellar initial mass function describes the mass distribution of stars at the time of their formation. This study reports observations of the Na I doublet and the Wing-Ford molecular FeH band in the spectra of elliptical galaxies. These lines are strong in stars with masses <0.3 solar masses and weak or absent in all other types of stars. The direct detection of the light of low-mass stars implies that they are very abundant in elliptical galaxies, making up >80% of the total number of stars and contributing >60% of the total stellar mass.

Galaxies normally have far more dark matter than normal matter, but the dynamics of objects within the ultra-diffuse galaxy NGC1052–DF2 suggest that it has a very little dark matter component.

Some of the strangest galaxies in the Universe just got stranger. It seems that many galaxies in the early Universe not only packed a huge number of stars into a very small volume, but were also rotating rapidly.

The dark-matter-free dwarf galaxies DF2 and DF4 in the NGC 1052 group probably formed together in the aftermath of a single bullet-dwarf collision around eight billion years ago.

The oldest and most luminous galaxies in the early Universe are surprisingly compact, having stellar masses similar to present-day elliptical galaxies but much smaller sizes. This suggests that massive galaxies have grown in size by a factor of about five over the past ten billion years, leading to the expectation that the stars in these galaxies have much higher velocities than those in present-day galaxies of the same mass. Here, the stellar velocity dispersion for a compact massive galaxy at redshift z = 2.186 is indeed found to be very high.

Hubble Space Telescope, Keck telescope and Spitzer satellite data reveal the formation of the dense stellar core of a massive galaxy occurring three billion years after the Big Bang.

The ratio of magnesium to iron abundance is measured for a massive quiescent galaxy at a redshift of 2.1, corresponding to when the Universe was three billion years old.

The number of long-period variable stars in a stellar population is directly related to their lifetime, which is difficult to predict from first principles; here a time-dependent stellar population model is constructed that includes the effects of long-period variable stars, and is applied to the galaxy M87.

A study of ¹²CO outflow emission from the protostellar source CARMA-7 in the cluster Serpens South suggests that episodic ejections of mass by the protostar begin in the earliest phase of protostellar evolution, probably providing a mechanism for driving the turbulence that is necessary for star formation in clusters.

A study of 36 massive galaxies at redshifts between 5 and 9 from the JWST FRESCO survey finds that galaxy formation of the most massive galaxies is 2–3 times higher than the most efficient galaxies at later epochs.

A rare perfect alignment between two galaxies in the young Universe has been captured by the James Webb Space Telescope. The further (z ≈ 3) galaxy is curved into an Einstein ring due to the bending of space around the nearer (z ≈ 2) galaxy, which is massive and compact—representative of the pristine core of a present-day galaxy.

Long-exposure spectra taken with the James Webb Space Telescope (JWST) reveal the most distant galaxies ever observed — back to a time when the Universe was only 2% of its present age.

JWST/NIRSpec observations of Abell2744-QSO1 show a high black-hole-to-host mass ratio in the early Universe, which indicates that we are seeing the black hole in a phase of rapid growth, accreting at 30% of the Eddington limit.

An analysis of eight ultra-faint galaxies during the epoch of reionization with absolute magnitudes between −17 mag and −15  mag shows that most of the photons that reionized the Universe come from dwarf galaxies.

James Webb Space Telescope early release observations used to search for intrinsically red galaxies from the first 750 million years of cosmic history find six candidate massive galaxies, possibly including one of roughly 10¹¹ solar masses.

The authors report 1.3 mm observations of dust emission from strongly lensed galaxies where star formation is quenched, demonstrating that gas depletion is responsible for the cessation of star formation in some high-redshift galaxies.