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We identify a source (J1507+3013) with an extended diffuse radio emission around an elliptical galaxy from the Very Large Array (VLA) Faint Images of Radio Sky at Twenty-cm (FIRST) survey. J1507+3013 possesses a morphology similar to the recently identified circular, low-surface-brightness, edge-brightened radio sources commonly known as odd radio circles (ORCs). Such diffuse emissions, as reported in this paper, are also found in mini-haloes and fossil radio galaxies, but the results presented here do not match the properties of mini-haloes or of fossil radio galaxies. The extended emission observed in J1507+3013 around an elliptical galaxy is a very rare class of diffuse emission that is unlike any previously known class of diffuse emission. The extended diffuse emission of J1507+3013 is also detected in the Low Frequency Array (LOFAR) at 144 MHz. J1507+3013 is hosted by an optical galaxy near the geometrical centre of the structure with a photometric redshift of z = 0.079. The physical extent of J1507+3013 is approximately 68 kpc, with a peak-to-peak angular size of 44 arcsec. It shows significantly higher flux densities compared with previously discovered ORCs. The spectral index of J1507+3013 varies between −0.90 and −1.4 in different regions of the diffuse structure, which is comparable to the case for previously discovered ORCs but less steep than for mini-haloes and fossil radio galaxies. If we consider J1507+3013 as a candidate ORC, then this would be the closest and most luminous ORC discovered so far. This paper describes the radio, spectral, and optical/IR properties of J1507+3013 in order to study the nature of this source. [ABSTRACT FROM AUTHOR]

The effect of angular momentum on galaxy formation and evolution has been studied for several decades. Our recent two papers using IllustrisTNG-100 simulation have revealed the acquisition path of the angular momentum from large-scale environment (satellites within hundreds of kpc) through the circumgalactic medium (CGM) to the stellar discs, putting forward the co-rotation scenario across the three distance scales. In real observations, although the rotation signature for the CGM and environmental three-dimensional angular momentum are difficult to obtain, line-of-sight kinematics of group member galaxies and stellar disc kinematics of central galaxies are available utilizing existing group catalogue data and integral field unit (IFU) data. In this paper, we use (1) the group catalogue of SDSS DR7 and MaNGA IFU stellar kinematic maps and (2) the group catalogue of GAMA DR4 data and SAMI IFU stellar kinematic maps, to test if the prediction above can be seen in real data. We found the co-rotation pattern between stellar discs and satellites can be concluded with 99.7 per cent confidence level (∼3σ) when combining the two data sets. And the random tests show that the signal can be scarcely drawn from random distribution. [ABSTRACT FROM AUTHOR]

Basilisk is a novel Bayesian hierarchical method for inferring the galaxy–halo connection, including its scatter, using the kinematics of satellite galaxies extracted from a redshift survey. In this paper, we introduce crucial improvements, such as updated central and satellite selection, advanced modelling of impurities and interlopers, extending the kinematic modelling to fourth order by including the kurtosis of the line-of-sight velocity distribution, and utilizing satellite abundance as additional constraint. This drastically enhances Basilisk 's performance, resulting in an unbiased recovery of the full conditional luminosity function (central and satellite) and with unprecedented precision. After validating Basilisk 's performance using realistic mock data, we apply it to the SDSS-DR7 data. The resulting inferences on the galaxy–halo connection are consistent with, but significantly tighter than, previous constraints from galaxy group catalogues, galaxy clustering, and galaxy–galaxy lensing. Using full projected phase-space information, Basilisk breaks the mass-anisotropy degeneracy, thus providing precise global constraint on the average orbital velocity anisotropy of satellite galaxies across a wide range of halo masses. Satellite orbits are found to be mildly radially anisotropic, in good agreement with the mean anisotropy for subhaloes in dark matter-only simulations. Thus, we establish Basilisk as a powerful tool that is not only more constraining than other methods on similar volumes of data, but crucially, is also insensitive to halo assembly bias which plagues the commonly used techniques like galaxy clustering and galaxy–galaxy lensing. [ABSTRACT FROM AUTHOR]

It is well known that stars are subject to radial migration, i.e. over time, they move away from their birth location. This dynamical process tends to mix different stellar populations and hence hinders the determination of the true chemical evolution of a galaxy (e.g. metallicity gradients). One way to account for radial migration is to infer stellar birth radii for individual stars. Many attempts to do so have been performed over the last few years, but are limited to the Milky Way, as computing the birth position of stars requires precise measurements of stellar metallicity and age for individual stars that cover large Galactic radii. Fortunately, recent and future surveys will provide numerous opportunities for inferring birth radii for external galaxies such as the LMC. In this paper, we investigate the possibility of doing so using the NIHAO cosmological zoom-in simulations. We find that it is theoretically possible to infer birth radii with a ∼25 per cent median uncertainty for individual stars in galaxies with i) orderliness of the orbits, |$\langle v_\phi \rangle /\sigma _{v} > 2 $|⁠ , ii) a dark matter halo mass greater or equal to approximately the LMC mass (∼2 × 1011  |${\rm M}_\odot$|⁠), and iii) after the average azimuthal velocity of the stellar disc reaches ∼70 per cent of its maximum. From our analysis, we conclude that it is possible and useful to infer birth radii for the LMC and other external galaxies that satisfy the above criteria. [ABSTRACT FROM AUTHOR]

We present a two-dimensional study of the gas distribution, excitation, and kinematics of the OH absorber galaxy IRAS 19154+2704 using Gemini Multi-Object Spectrograph integral field unit observations. Its continuum image shows a disturbed morphology indicative of a past or ongoing interaction. The ionized gas emission presents two kinematic components: a narrow (σ ≲ 300 km s−1) component that may be tracing the gas orbiting in the galaxy potential and a broad (σ ≳ 500 km s−1) component, which is produced by an active galactic nucleus (AGN)-driven outflow, with velocities reaching −500 km s−1, which may exceed the escape velocity of the galaxy. The emission-line ratios and Baldwin–Phillips–Terlevich diagrams confirm that the gas excitation in the inner ∼2 kpc is mainly due to the AGN, while in regions farther away, a contribution from star formation is observed. We estimate a mass-outflow rate of |$\dot{M}_{\rm out}=4.0\pm 2.6$|  M⊙ yr−1 at a distance of 850 pc from the nucleus. The corresponding outflow kinetic power, |$\dot{E}_{\rm out} = (2.5\pm 1.6)\times 10^{42}$|  erg s−1, is only 3 × 10−4 Lbol (the AGN luminosity), but the large mass-outflow rate, if kept for an ∼10 Myr AGN life cycle, will expel ≈108 M⊙ in ionized gas alone. This is the sixth of a series of papers in which we have investigated the kinematics of ultra-luminous infrared galaxies, most of which are interacting galaxies showing OH megamasers. IRAS 19154 shows the strongest signatures of an active AGN, supporting an evolutionary scenario: interactions trigger AGN that fully appears in the most advanced stages of the interaction. [ABSTRACT FROM AUTHOR]

This paper presents the third data release of the INvestigating Stellar Population In RElics (INSPIRE) project, comprising 52 ultra-compact massive galaxies (UCMGs) observed with the X-Shooter spectrograph. We measure integrated stellar velocity dispersion, [Mg/Fe] abundances, ages, and metallicities for all the INSPIRE objects. We thus infer star formation histories and confirm the existence of a degree of relicness (DoR), defined in terms of the fraction of stellar mass formed by z  = 2, the time at which a galaxy has assembled 75 per cent of its mass, and the final assembly time. Objects with a high DoR assembled their stellar mass at early epochs, while low-DoR objects show a non-negligible fraction of later formed populations and hence a spread in ages and metallicities. A higher DoR correlates with larger [Mg/Fe], supersolar metallicity, and larger velocity dispersion values. The 52 UMCGs span a large range of DoR from 0.83 to 0.06, with 38 of them having formed more than 75  per cent of their mass by z  = 2. Of these, nine are extreme relics (DoR>0.7), since they formed the totality (⁠|$\gt 99~{{\ \rm per\ cent}}$|⁠) of their stellar mass by redshift z  = 2. The remaining 14 UCMGs cannot be considered relics, as they are characterized by more extended star formation histories. With INSPIRE  we built the first sizeable sample of relics outside the local Universe, up to z ∼ 0.4, increasing the number of confirmed relics by a factor of >10, and opening up an important window to explain the mass assembly of massive galaxies in the high- z Universe. [ABSTRACT FROM AUTHOR]

Measurements of the dependence of stellar specific angular momentum (j *) on stellar mass (M *) are presented for large samples of galaxies from the Arecibo Legacy Fast ALFA (ALFALFA) survey, spanning the stellar mass range ∼108–1011 M⊙. Accurate estimates of j * are generated using measurements of I -band effective radius and velocity width of the H  i line profile. While the full sample (N = 3607) of galaxies yields a j *– M * relation with power-law index α = 0.404 ± 0.03, it is shown that various subsamples have indices that are very similar to the best literature results, yet with comparatively lower intrinsic scatters. A galaxy's mean I -band surface brightness within its effective radius (<μeff>) is shown to significantly correlate with j *– M * scatter. A 3D plane fit to all N = 3607 galaxies in log10 j *–log10 M *–<μeff> space yields j * ∝ M 0.589 ± 0.002 <μeff>0.193 ± 0.002 with scatter σ = 0.089 dex. <μeff>-selected subsamples of size up to N = 1450 yield power-law j *– M * relations mostly consistent with α = 0.55 ± 0.02 from the literature and with intrinsic scatter ranging from 0.083 to 0.129 dex. Thus, this paper presents new, highly accurate measurements of the j *– M * relation that can be used to better understand the important roles played by angular momentum in the formation and evolution of galaxies. [ABSTRACT FROM AUTHOR]