[Abbreviated] We present the results of a near-infrared (NIR) spectroscopic follow-up survey of 182 M4-L7 low-mass stars and brown dwarfs (BDs) from the BANYAN All-Sky Survey (BASS) for candidate members of nearby, young moving groups (YMGs). We confirm signs of low-gravity for 42 new BD discoveries with estimated masses between 8-75 $M_{Jup}$ and identify previously unrecognized signs of low gravity for 24 known BDs. This allows us to refine the fraction of low-gravity dwarfs in the high-probability BASS sample to $\sim$82%. We use this unique sample of 66 young BDs, supplemented with 22 young BDs from the literature, to construct new empirical NIR absolute magnitude and color sequences for low-gravity BDs. We obtain a spectroscopic confirmation of low-gravity for 2MASS J14252798-3650229, which is a new $\sim$27 $M_{Jup}$, L4 $\gamma$ bona fide member of AB Doradus. We identify a total of 19 new low-gravity candidate members of YMGs with estimated masses below 13 $M_{Jup}$, seven of which have kinematically estimated distances within 40 pc. These objects will be valuable benchmarks for a detailed atmospheric characterization of planetary-mass objects with the next generation of instruments. We find 16 strong candidate members of the Tucana-Horologium association with estimated masses between 12.5-14 $M_{Jup}$, a regime where our study was particularly sensitive. This would indicate that for this association there is at least one isolated object in this mass range for every $17.5_{-5.0}^{+6.6}$ main-sequence stellar member, a number significantly higher than expected based on standard log-normal initial mass function, however in the absence of radial velocity and parallax measurements for all of them, it is likely that this over-density is caused by a number of young interlopers from other moving groups. We identify 12 new L0-L5 field BDs, seven of which display peculiar properties.

https://iopscience.iop.org/article/10.1088/0067-0049/219/2/33/pdf

BANYAN. VII. A New Population of Young Substellar Candidate Members of Nearby Moving Groups from the BASS Survey

Mid-infrared observations of the central source of NGC 1068 have been obtained with a spatial resolution in the deconvolved image of 0.”1 (~7 pc). The central source is extended by ~1'' in the north-south direction but appears unresolved in the east-west direction over most of its length. About 2/3 of its flux can be ascribed to a core structure that is itself elongated north-south and does not show a distinct unresolved compact source. The source is strongly asymmetric, extending significantly farther to the north than to the south. The morphology of the mid-infrared emission appears similar to that of the radio jet and has features which correlate with the images in [O III]. Its 12.5–24.5 μm color temperature ranges from 215 to 260 K and does not decrease smoothly with distance from the core. Silicate absorption is strongest in the core and to the south and is small in the north. The core, apparently containing 2/3 of the bolometric luminosity of the inner 4'' diameter area, may be explained by a thick, dusty torus near the central active galactic nucleus (AGN) viewed at an angle of ~65° to its plane. There are, however, detailed difficulties with existing models, especially the narrow east-west width of the thin extended mid-infrared "tongue" to the north of the core. We interpret the tongue as reprocessed visual and ultraviolet radiation that is strongly beamed and that originates in the AGN.

/pdf/high-spatial-resolution-imaging-of-ngc-1068-in-the-mid-1lz0dmb7f1.pdf

High Spatial Resolution Imaging of NGC 1068 in the Mid-Infrared

Low-frequency radio surveys are ideal for selecting orientation-independent samples of extragalactic sources because the sample members are selected by virtue of their isotropic steep-spectrum extended emission. We use the new 7C Redshift Survey along with the brighter 3CRR and 6C samples to investigate the fraction of objects with observed broad emission lines - the 'quasar fraction' - as a function of redshift and of radio and narrow emission line luminosity. We find that the quasar fraction is more strongly dependent upon luminosity (both narrow line and radio) than it is on redshift. Above a narrow [OII] emission line luminosity of log(base 10) (L(sub [OII])/W) approximately > 35 [or radio luminosity log(base 10) (L(sub 151)/ W/Hz.sr) approximately > 26.5], the quasar fraction is virtually independent of redshift and luminosity; this is consistent with a simple unified scheme with an obscuring torus with a half-opening angle theta(sub trans) approximately equal 53 deg. For objects with less luminous narrow lines, the quasar fraction is lower. We show that this is not due to the difficulty of detecting lower-luminosity broad emission lines in a less luminous, but otherwise similar, quasar population. We discuss evidence which supports at least two probable physical causes for the drop in quasar fraction at low luminosity: (i) a gradual decrease in theta(sub trans) and/or a gradual increase in the fraction of lightly-reddened (0 approximately < A(sub V) approximately < 5) lines-of-sight with decreasing quasar luminosity; and (ii) the emergence of a distinct second population of low luminosity radio sources which, like M8T, lack a well-fed quasar nucleus and may well lack a thick obscuring torus.

/pdf/the-quasar-fraction-in-low-frequency-selected-complete-1jg8jh4hed.pdf

The Quasar Fraction in Low-Frequency Selected Complete Samples and Implications for Unified Schemes

We report novel, high angular resolution interferometric measurements that imply that the near-infrared nuclear emission in NGC 4151 is unexpectedly compact. We have observed the nucleus of NGC 4151 at 2.2 μm using the two 10 m Keck telescopes as an interferometer and find a marginally resolved source ≤0.1 pc in diameter. Our measurements rule out models in which a majority of the K-band nuclear emission is produced on scales larger than this size. The interpretation of our measurement most consistent with other observations is that the emission mainly originates directly in the central accretion disk. This implies that active galactic nucleus unification models invoking hot, optically thick dust may not be applicable to NGC 4151.

Interferometer Observations of Subparsec-Scale Infrared Emission in the Nucleus of NGC 4151

/pdf/broadband-optical-and-infrared-observations-of-seyfert-1w0z1dirch.pdf

Broadband Optical and Infrared Observations of Seyfert Galaxies

A new complex of infrared sources about one minute across has been discovered in Orion. Associated with this cluster is an extended molecular cloud producing intense CO emission. Its measured infrared luminosity is less than 500 times the luminosity of the sun. The complex is hypothesized to be composed of pre-main-sequence sources. Several arguments suggest that these stars heat dust in the larger molecular cloud and thus cause the strong CO emission. The complex is not associated with a known visible or radio continuum feature, and searches over a 0.7 x 0.7-deg field show no other comparable unknown 2.2-micron sources.

/pdf/a-new-infrared-complex-and-molecular-cloud-in-orion-1e938t4dsy.pdf

A new infrared complex and molecular cloud in Orion

/pdf/observations-of-ngc-4151-during-1970-in-the-optical-and-42sjqhqxyb.pdf

Observations of NGC 4151 During 1970 in the Optical and Infra-red

Observations of NGC 4151 During 1970 in the Optical and Infrared.

Oke1 and Sandage2 have shown that the N-galaxy 3C371 is variable. This communication reports the discovery that the similar system 3C390.3 has been varying by up to about 1.5m during the past 70 years. This is interpreted as showing that at least some quasars are cosmological.

M. V. Penston

Papers

Broadband Optical and Infrared Observations of Seyfert Galaxies

A new infrared complex and molecular cloud in Orion

Observations of NGC 4151 During 1970 in the Optical and Infra-red

Observations of NGC 4151 During 1970 in the Optical and Infrared.

3C390.3, a Second Variable N-Galaxy